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linux_dsm_epyc7002/include/linux/skbuff.h
Daniel Borkmann 5293efe62d bpf: add bpf_skb_change_tail helper 
This work adds a bpf_skb_change_tail() helper for tc BPF programs. The
basic idea is to expand or shrink the skb in a controlled manner. The
eBPF program can then rewrite the rest via helpers like bpf_skb_store_bytes(),
bpf_lX_csum_replace() and others rather than passing a raw buffer for
writing here.

bpf_skb_change_tail() is really a slow path helper and intended for
replies with f.e. ICMP control messages. Concept is similar to other
helpers like bpf_skb_change_proto() helper to keep the helper without
protocol specifics and let the BPF program mangle the remaining parts.
A flags field has been added and is reserved for now should we extend
the helper in future.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-18 23:38:16 -07:00

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/*
* Definitions for the 'struct sk_buff' memory handlers.
*
* Authors:
* Alan Cox, <gw4pts@gw4pts.ampr.org>
* Florian La Roche, <rzsfl@rz.uni-sb.de>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _LINUX_SKBUFF_H
#define _LINUX_SKBUFF_H
#include <linux/kernel.h>
#include <linux/kmemcheck.h>
#include <linux/compiler.h>
#include <linux/time.h>
#include <linux/bug.h>
#include <linux/cache.h>
#include <linux/rbtree.h>
#include <linux/socket.h>
#include <linux/atomic.h>
#include <asm/types.h>
#include <linux/spinlock.h>
#include <linux/net.h>
#include <linux/textsearch.h>
#include <net/checksum.h>
#include <linux/rcupdate.h>
#include <linux/hrtimer.h>
#include <linux/dma-mapping.h>
#include <linux/netdev_features.h>
#include <linux/sched.h>
#include <net/flow_dissector.h>
#include <linux/splice.h>
#include <linux/in6.h>
#include <linux/if_packet.h>
#include <net/flow.h>
/* The interface for checksum offload between the stack and networking drivers
* is as follows...
*
* A. IP checksum related features
*
* Drivers advertise checksum offload capabilities in the features of a device.
* From the stack's point of view these are capabilities offered by the driver,
* a driver typically only advertises features that it is capable of offloading
* to its device.
*
* The checksum related features are:
*
* NETIF_F_HW_CSUM - The driver (or its device) is able to compute one
* IP (one's complement) checksum for any combination
* of protocols or protocol layering. The checksum is
* computed and set in a packet per the CHECKSUM_PARTIAL
* interface (see below).
*
* NETIF_F_IP_CSUM - Driver (device) is only able to checksum plain
* TCP or UDP packets over IPv4. These are specifically
* unencapsulated packets of the form IPv4|TCP or
* IPv4|UDP where the Protocol field in the IPv4 header
* is TCP or UDP. The IPv4 header may contain IP options
* This feature cannot be set in features for a device
* with NETIF_F_HW_CSUM also set. This feature is being
* DEPRECATED (see below).
*
* NETIF_F_IPV6_CSUM - Driver (device) is only able to checksum plain
* TCP or UDP packets over IPv6. These are specifically
* unencapsulated packets of the form IPv6|TCP or
* IPv4|UDP where the Next Header field in the IPv6
* header is either TCP or UDP. IPv6 extension headers
* are not supported with this feature. This feature
* cannot be set in features for a device with
* NETIF_F_HW_CSUM also set. This feature is being
* DEPRECATED (see below).
*
* NETIF_F_RXCSUM - Driver (device) performs receive checksum offload.
* This flag is used only used to disable the RX checksum
* feature for a device. The stack will accept receive
* checksum indication in packets received on a device
* regardless of whether NETIF_F_RXCSUM is set.
*
* B. Checksumming of received packets by device. Indication of checksum
* verification is in set skb->ip_summed. Possible values are:
*
* CHECKSUM_NONE:
*
* Device did not checksum this packet e.g. due to lack of capabilities.
* The packet contains full (though not verified) checksum in packet but
* not in skb->csum. Thus, skb->csum is undefined in this case.
*
* CHECKSUM_UNNECESSARY:
*
* The hardware you're dealing with doesn't calculate the full checksum
* (as in CHECKSUM_COMPLETE), but it does parse headers and verify checksums
* for specific protocols. For such packets it will set CHECKSUM_UNNECESSARY
* if their checksums are okay. skb->csum is still undefined in this case
* though. A driver or device must never modify the checksum field in the
* packet even if checksum is verified.
*
* CHECKSUM_UNNECESSARY is applicable to following protocols:
* TCP: IPv6 and IPv4.
* UDP: IPv4 and IPv6. A device may apply CHECKSUM_UNNECESSARY to a
* zero UDP checksum for either IPv4 or IPv6, the networking stack
* may perform further validation in this case.
* GRE: only if the checksum is present in the header.
* SCTP: indicates the CRC in SCTP header has been validated.
*
* skb->csum_level indicates the number of consecutive checksums found in
* the packet minus one that have been verified as CHECKSUM_UNNECESSARY.
* For instance if a device receives an IPv6->UDP->GRE->IPv4->TCP packet
* and a device is able to verify the checksums for UDP (possibly zero),
* GRE (checksum flag is set), and TCP-- skb->csum_level would be set to
* two. If the device were only able to verify the UDP checksum and not
* GRE, either because it doesn't support GRE checksum of because GRE
* checksum is bad, skb->csum_level would be set to zero (TCP checksum is
* not considered in this case).
*
* CHECKSUM_COMPLETE:
*
* This is the most generic way. The device supplied checksum of the _whole_
* packet as seen by netif_rx() and fills out in skb->csum. Meaning, the
* hardware doesn't need to parse L3/L4 headers to implement this.
*
* Note: Even if device supports only some protocols, but is able to produce
* skb->csum, it MUST use CHECKSUM_COMPLETE, not CHECKSUM_UNNECESSARY.
*
* CHECKSUM_PARTIAL:
*
* A checksum is set up to be offloaded to a device as described in the
* output description for CHECKSUM_PARTIAL. This may occur on a packet
* received directly from another Linux OS, e.g., a virtualized Linux kernel
* on the same host, or it may be set in the input path in GRO or remote
* checksum offload. For the purposes of checksum verification, the checksum
* referred to by skb->csum_start + skb->csum_offset and any preceding
* checksums in the packet are considered verified. Any checksums in the
* packet that are after the checksum being offloaded are not considered to
* be verified.
*
* C. Checksumming on transmit for non-GSO. The stack requests checksum offload
* in the skb->ip_summed for a packet. Values are:
*
* CHECKSUM_PARTIAL:
*
* The driver is required to checksum the packet as seen by hard_start_xmit()
* from skb->csum_start up to the end, and to record/write the checksum at
* offset skb->csum_start + skb->csum_offset. A driver may verify that the
* csum_start and csum_offset values are valid values given the length and
* offset of the packet, however they should not attempt to validate that the
* checksum refers to a legitimate transport layer checksum-- it is the
* purview of the stack to validate that csum_start and csum_offset are set
* correctly.
*
* When the stack requests checksum offload for a packet, the driver MUST
* ensure that the checksum is set correctly. A driver can either offload the
* checksum calculation to the device, or call skb_checksum_help (in the case
* that the device does not support offload for a particular checksum).
*
* NETIF_F_IP_CSUM and NETIF_F_IPV6_CSUM are being deprecated in favor of
* NETIF_F_HW_CSUM. New devices should use NETIF_F_HW_CSUM to indicate
* checksum offload capability. If a device has limited checksum capabilities
* (for instance can only perform NETIF_F_IP_CSUM or NETIF_F_IPV6_CSUM as
* described above) a helper function can be called to resolve
* CHECKSUM_PARTIAL. The helper functions are skb_csum_off_chk*. The helper
* function takes a spec argument that describes the protocol layer that is
* supported for checksum offload and can be called for each packet. If a
* packet does not match the specification for offload, skb_checksum_help
* is called to resolve the checksum.
*
* CHECKSUM_NONE:
*
* The skb was already checksummed by the protocol, or a checksum is not
* required.
*
* CHECKSUM_UNNECESSARY:
*
* This has the same meaning on as CHECKSUM_NONE for checksum offload on
* output.
*
* CHECKSUM_COMPLETE:
* Not used in checksum output. If a driver observes a packet with this value
* set in skbuff, if should treat as CHECKSUM_NONE being set.
*
* D. Non-IP checksum (CRC) offloads
*
* NETIF_F_SCTP_CRC - This feature indicates that a device is capable of
* offloading the SCTP CRC in a packet. To perform this offload the stack
* will set ip_summed to CHECKSUM_PARTIAL and set csum_start and csum_offset
* accordingly. Note the there is no indication in the skbuff that the
* CHECKSUM_PARTIAL refers to an SCTP checksum, a driver that supports
* both IP checksum offload and SCTP CRC offload must verify which offload
* is configured for a packet presumably by inspecting packet headers.
*
* NETIF_F_FCOE_CRC - This feature indicates that a device is capable of
* offloading the FCOE CRC in a packet. To perform this offload the stack
* will set ip_summed to CHECKSUM_PARTIAL and set csum_start and csum_offset
* accordingly. Note the there is no indication in the skbuff that the
* CHECKSUM_PARTIAL refers to an FCOE checksum, a driver that supports
* both IP checksum offload and FCOE CRC offload must verify which offload
* is configured for a packet presumably by inspecting packet headers.
*
* E. Checksumming on output with GSO.
*
* In the case of a GSO packet (skb_is_gso(skb) is true), checksum offload
* is implied by the SKB_GSO_* flags in gso_type. Most obviously, if the
* gso_type is SKB_GSO_TCPV4 or SKB_GSO_TCPV6, TCP checksum offload as
* part of the GSO operation is implied. If a checksum is being offloaded
* with GSO then ip_summed is CHECKSUM_PARTIAL, csum_start and csum_offset
* are set to refer to the outermost checksum being offload (two offloaded
* checksums are possible with UDP encapsulation).
*/
/* Don't change this without changing skb_csum_unnecessary! */
#define CHECKSUM_NONE 0
#define CHECKSUM_UNNECESSARY 1
#define CHECKSUM_COMPLETE 2
#define CHECKSUM_PARTIAL 3
/* Maximum value in skb->csum_level */
#define SKB_MAX_CSUM_LEVEL 3
#define SKB_DATA_ALIGN(X) ALIGN(X, SMP_CACHE_BYTES)
#define SKB_WITH_OVERHEAD(X) \
((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
#define SKB_MAX_ORDER(X, ORDER) \
SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
#define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
#define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))
/* return minimum truesize of one skb containing X bytes of data */
#define SKB_TRUESIZE(X) ((X) + \
SKB_DATA_ALIGN(sizeof(struct sk_buff)) + \
SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
struct net_device;
struct scatterlist;
struct pipe_inode_info;
struct iov_iter;
struct napi_struct;
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
struct nf_conntrack {
atomic_t use;
};
#endif
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
struct nf_bridge_info {
atomic_t use;
enum {
BRNF_PROTO_UNCHANGED,
BRNF_PROTO_8021Q,
BRNF_PROTO_PPPOE
} orig_proto:8;
u8 pkt_otherhost:1;
u8 in_prerouting:1;
u8 bridged_dnat:1;
__u16 frag_max_size;
struct net_device *physindev;
/* always valid & non-NULL from FORWARD on, for physdev match */
struct net_device *physoutdev;
union {
/* prerouting: detect dnat in orig/reply direction */
__be32 ipv4_daddr;
struct in6_addr ipv6_daddr;
/* after prerouting + nat detected: store original source
* mac since neigh resolution overwrites it, only used while
* skb is out in neigh layer.
*/
char neigh_header[8];
};
};
#endif
struct sk_buff_head {
/* These two members must be first. */
struct sk_buff *next;
struct sk_buff *prev;
__u32 qlen;
spinlock_t lock;
};
struct sk_buff;
/* To allow 64K frame to be packed as single skb without frag_list we
* require 64K/PAGE_SIZE pages plus 1 additional page to allow for
* buffers which do not start on a page boundary.
*
* Since GRO uses frags we allocate at least 16 regardless of page
* size.
*/
#if (65536/PAGE_SIZE + 1) < 16
#define MAX_SKB_FRAGS 16UL
#else
#define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1)
#endif
extern int sysctl_max_skb_frags;
/* Set skb_shinfo(skb)->gso_size to this in case you want skb_segment to
* segment using its current segmentation instead.
*/
#define GSO_BY_FRAGS 0xFFFF
typedef struct skb_frag_struct skb_frag_t;
struct skb_frag_struct {
struct {
struct page *p;
} page;
#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
__u32 page_offset;
__u32 size;
#else
__u16 page_offset;
__u16 size;
#endif
};
static inline unsigned int skb_frag_size(const skb_frag_t *frag)
{
return frag->size;
}
static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
{
frag->size = size;
}
static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
{
frag->size += delta;
}
static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
{
frag->size -= delta;
}
#define HAVE_HW_TIME_STAMP
/**
* struct skb_shared_hwtstamps - hardware time stamps
* @hwtstamp: hardware time stamp transformed into duration
* since arbitrary point in time
*
* Software time stamps generated by ktime_get_real() are stored in
* skb->tstamp.
*
* hwtstamps can only be compared against other hwtstamps from
* the same device.
*
* This structure is attached to packets as part of the
* &skb_shared_info. Use skb_hwtstamps() to get a pointer.
*/
struct skb_shared_hwtstamps {
ktime_t hwtstamp;
};
/* Definitions for tx_flags in struct skb_shared_info */
enum {
/* generate hardware time stamp */
SKBTX_HW_TSTAMP = 1 << 0,
/* generate software time stamp when queueing packet to NIC */
SKBTX_SW_TSTAMP = 1 << 1,
/* device driver is going to provide hardware time stamp */
SKBTX_IN_PROGRESS = 1 << 2,
/* device driver supports TX zero-copy buffers */
SKBTX_DEV_ZEROCOPY = 1 << 3,
/* generate wifi status information (where possible) */
SKBTX_WIFI_STATUS = 1 << 4,
/* This indicates at least one fragment might be overwritten
* (as in vmsplice(), sendfile() ...)
* If we need to compute a TX checksum, we'll need to copy
* all frags to avoid possible bad checksum
*/
SKBTX_SHARED_FRAG = 1 << 5,
/* generate software time stamp when entering packet scheduling */
SKBTX_SCHED_TSTAMP = 1 << 6,
};
#define SKBTX_ANY_SW_TSTAMP (SKBTX_SW_TSTAMP | \
SKBTX_SCHED_TSTAMP)
#define SKBTX_ANY_TSTAMP (SKBTX_HW_TSTAMP | SKBTX_ANY_SW_TSTAMP)
/*
* The callback notifies userspace to release buffers when skb DMA is done in
* lower device, the skb last reference should be 0 when calling this.
* The zerocopy_success argument is true if zero copy transmit occurred,
* false on data copy or out of memory error caused by data copy attempt.
* The ctx field is used to track device context.
* The desc field is used to track userspace buffer index.
*/
struct ubuf_info {
void (*callback)(struct ubuf_info *, bool zerocopy_success);
void *ctx;
unsigned long desc;
};
/* This data is invariant across clones and lives at
* the end of the header data, ie. at skb->end.
*/
struct skb_shared_info {
unsigned char nr_frags;
__u8 tx_flags;
unsigned short gso_size;
/* Warning: this field is not always filled in (UFO)! */
unsigned short gso_segs;
unsigned short gso_type;
struct sk_buff *frag_list;
struct skb_shared_hwtstamps hwtstamps;
u32 tskey;
__be32 ip6_frag_id;
/*
* Warning : all fields before dataref are cleared in __alloc_skb()
*/
atomic_t dataref;
/* Intermediate layers must ensure that destructor_arg
* remains valid until skb destructor */
void * destructor_arg;
/* must be last field, see pskb_expand_head() */
skb_frag_t frags[MAX_SKB_FRAGS];
};
/* We divide dataref into two halves. The higher 16 bits hold references
* to the payload part of skb->data. The lower 16 bits hold references to
* the entire skb->data. A clone of a headerless skb holds the length of
* the header in skb->hdr_len.
*
* All users must obey the rule that the skb->data reference count must be
* greater than or equal to the payload reference count.
*
* Holding a reference to the payload part means that the user does not
* care about modifications to the header part of skb->data.
*/
#define SKB_DATAREF_SHIFT 16
#define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
enum {
SKB_FCLONE_UNAVAILABLE, /* skb has no fclone (from head_cache) */
SKB_FCLONE_ORIG, /* orig skb (from fclone_cache) */
SKB_FCLONE_CLONE, /* companion fclone skb (from fclone_cache) */
};
enum {
SKB_GSO_TCPV4 = 1 << 0,
SKB_GSO_UDP = 1 << 1,
/* This indicates the skb is from an untrusted source. */
SKB_GSO_DODGY = 1 << 2,
/* This indicates the tcp segment has CWR set. */
SKB_GSO_TCP_ECN = 1 << 3,
SKB_GSO_TCP_FIXEDID = 1 << 4,
SKB_GSO_TCPV6 = 1 << 5,
SKB_GSO_FCOE = 1 << 6,
SKB_GSO_GRE = 1 << 7,
SKB_GSO_GRE_CSUM = 1 << 8,
SKB_GSO_IPXIP4 = 1 << 9,
SKB_GSO_IPXIP6 = 1 << 10,
SKB_GSO_UDP_TUNNEL = 1 << 11,
SKB_GSO_UDP_TUNNEL_CSUM = 1 << 12,
SKB_GSO_PARTIAL = 1 << 13,
SKB_GSO_TUNNEL_REMCSUM = 1 << 14,
SKB_GSO_SCTP = 1 << 15,
};
#if BITS_PER_LONG > 32
#define NET_SKBUFF_DATA_USES_OFFSET 1
#endif
#ifdef NET_SKBUFF_DATA_USES_OFFSET
typedef unsigned int sk_buff_data_t;
#else
typedef unsigned char *sk_buff_data_t;
#endif
/**
* struct skb_mstamp - multi resolution time stamps
* @stamp_us: timestamp in us resolution
* @stamp_jiffies: timestamp in jiffies
*/
struct skb_mstamp {
union {
u64 v64;
struct {
u32 stamp_us;
u32 stamp_jiffies;
};
};
};
/**
* skb_mstamp_get - get current timestamp
* @cl: place to store timestamps
*/
static inline void skb_mstamp_get(struct skb_mstamp *cl)
{
u64 val = local_clock();
do_div(val, NSEC_PER_USEC);
cl->stamp_us = (u32)val;
cl->stamp_jiffies = (u32)jiffies;
}
/**
* skb_mstamp_delta - compute the difference in usec between two skb_mstamp
* @t1: pointer to newest sample
* @t0: pointer to oldest sample
*/
static inline u32 skb_mstamp_us_delta(const struct skb_mstamp *t1,
const struct skb_mstamp *t0)
{
s32 delta_us = t1->stamp_us - t0->stamp_us;
u32 delta_jiffies = t1->stamp_jiffies - t0->stamp_jiffies;
/* If delta_us is negative, this might be because interval is too big,
* or local_clock() drift is too big : fallback using jiffies.
*/
if (delta_us <= 0 ||
delta_jiffies >= (INT_MAX / (USEC_PER_SEC / HZ)))
delta_us = jiffies_to_usecs(delta_jiffies);
return delta_us;
}
static inline bool skb_mstamp_after(const struct skb_mstamp *t1,
const struct skb_mstamp *t0)
{
s32 diff = t1->stamp_jiffies - t0->stamp_jiffies;
if (!diff)
diff = t1->stamp_us - t0->stamp_us;
return diff > 0;
}
/**
* struct sk_buff - socket buffer
* @next: Next buffer in list
* @prev: Previous buffer in list
* @tstamp: Time we arrived/left
* @rbnode: RB tree node, alternative to next/prev for netem/tcp
* @sk: Socket we are owned by
* @dev: Device we arrived on/are leaving by
* @cb: Control buffer. Free for use by every layer. Put private vars here
* @_skb_refdst: destination entry (with norefcount bit)
* @sp: the security path, used for xfrm
* @len: Length of actual data
* @data_len: Data length
* @mac_len: Length of link layer header
* @hdr_len: writable header length of cloned skb
* @csum: Checksum (must include start/offset pair)
* @csum_start: Offset from skb->head where checksumming should start
* @csum_offset: Offset from csum_start where checksum should be stored
* @priority: Packet queueing priority
* @ignore_df: allow local fragmentation
* @cloned: Head may be cloned (check refcnt to be sure)
* @ip_summed: Driver fed us an IP checksum
* @nohdr: Payload reference only, must not modify header
* @nfctinfo: Relationship of this skb to the connection
* @pkt_type: Packet class
* @fclone: skbuff clone status
* @ipvs_property: skbuff is owned by ipvs
* @peeked: this packet has been seen already, so stats have been
* done for it, don't do them again
* @nf_trace: netfilter packet trace flag
* @protocol: Packet protocol from driver
* @destructor: Destruct function
* @nfct: Associated connection, if any
* @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
* @skb_iif: ifindex of device we arrived on
* @tc_index: Traffic control index
* @tc_verd: traffic control verdict
* @hash: the packet hash
* @queue_mapping: Queue mapping for multiqueue devices
* @xmit_more: More SKBs are pending for this queue
* @ndisc_nodetype: router type (from link layer)
* @ooo_okay: allow the mapping of a socket to a queue to be changed
* @l4_hash: indicate hash is a canonical 4-tuple hash over transport
* ports.
* @sw_hash: indicates hash was computed in software stack
* @wifi_acked_valid: wifi_acked was set
* @wifi_acked: whether frame was acked on wifi or not
* @no_fcs: Request NIC to treat last 4 bytes as Ethernet FCS
* @napi_id: id of the NAPI struct this skb came from
* @secmark: security marking
* @offload_fwd_mark: fwding offload mark
* @mark: Generic packet mark
* @vlan_proto: vlan encapsulation protocol
* @vlan_tci: vlan tag control information
* @inner_protocol: Protocol (encapsulation)
* @inner_transport_header: Inner transport layer header (encapsulation)
* @inner_network_header: Network layer header (encapsulation)
* @inner_mac_header: Link layer header (encapsulation)
* @transport_header: Transport layer header
* @network_header: Network layer header
* @mac_header: Link layer header
* @tail: Tail pointer
* @end: End pointer
* @head: Head of buffer
* @data: Data head pointer
* @truesize: Buffer size
* @users: User count - see {datagram,tcp}.c
*/
struct sk_buff {
union {
struct {
/* These two members must be first. */
struct sk_buff *next;
struct sk_buff *prev;
union {
ktime_t tstamp;
struct skb_mstamp skb_mstamp;
};
};
struct rb_node rbnode; /* used in netem & tcp stack */
};
struct sock *sk;
struct net_device *dev;
/*
* This is the control buffer. It is free to use for every
* layer. Please put your private variables there. If you
* want to keep them across layers you have to do a skb_clone()
* first. This is owned by whoever has the skb queued ATM.
*/
char cb[48] __aligned(8);
unsigned long _skb_refdst;
void (*destructor)(struct sk_buff *skb);
#ifdef CONFIG_XFRM
struct sec_path *sp;
#endif
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
struct nf_conntrack *nfct;
#endif
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
struct nf_bridge_info *nf_bridge;
#endif
unsigned int len,
data_len;
__u16 mac_len,
hdr_len;
/* Following fields are _not_ copied in __copy_skb_header()
* Note that queue_mapping is here mostly to fill a hole.
*/
kmemcheck_bitfield_begin(flags1);
__u16 queue_mapping;
__u8 cloned:1,
nohdr:1,
fclone:2,
peeked:1,
head_frag:1,
xmit_more:1;
/* one bit hole */
kmemcheck_bitfield_end(flags1);
/* fields enclosed in headers_start/headers_end are copied
* using a single memcpy() in __copy_skb_header()
*/
/* private: */
__u32 headers_start[0];
/* public: */
/* if you move pkt_type around you also must adapt those constants */
#ifdef __BIG_ENDIAN_BITFIELD
#define PKT_TYPE_MAX (7 << 5)
#else
#define PKT_TYPE_MAX 7
#endif
#define PKT_TYPE_OFFSET() offsetof(struct sk_buff, __pkt_type_offset)
__u8 __pkt_type_offset[0];
__u8 pkt_type:3;
__u8 pfmemalloc:1;
__u8 ignore_df:1;
__u8 nfctinfo:3;
__u8 nf_trace:1;
__u8 ip_summed:2;
__u8 ooo_okay:1;
__u8 l4_hash:1;
__u8 sw_hash:1;
__u8 wifi_acked_valid:1;
__u8 wifi_acked:1;
__u8 no_fcs:1;
/* Indicates the inner headers are valid in the skbuff. */
__u8 encapsulation:1;
__u8 encap_hdr_csum:1;
__u8 csum_valid:1;
__u8 csum_complete_sw:1;
__u8 csum_level:2;
__u8 csum_bad:1;
#ifdef CONFIG_IPV6_NDISC_NODETYPE
__u8 ndisc_nodetype:2;
#endif
__u8 ipvs_property:1;
__u8 inner_protocol_type:1;
__u8 remcsum_offload:1;
/* 3 or 5 bit hole */
#ifdef CONFIG_NET_SCHED
__u16 tc_index; /* traffic control index */
#ifdef CONFIG_NET_CLS_ACT
__u16 tc_verd; /* traffic control verdict */
#endif
#endif
union {
__wsum csum;
struct {
__u16 csum_start;
__u16 csum_offset;
};
};
__u32 priority;
int skb_iif;
__u32 hash;
__be16 vlan_proto;
__u16 vlan_tci;
#if defined(CONFIG_NET_RX_BUSY_POLL) || defined(CONFIG_XPS)
union {
unsigned int napi_id;
unsigned int sender_cpu;
};
#endif
union {
#ifdef CONFIG_NETWORK_SECMARK
__u32 secmark;
#endif
#ifdef CONFIG_NET_SWITCHDEV
__u32 offload_fwd_mark;
#endif
};
union {
__u32 mark;
__u32 reserved_tailroom;
};
union {
__be16 inner_protocol;
__u8 inner_ipproto;
};
__u16 inner_transport_header;
__u16 inner_network_header;
__u16 inner_mac_header;
__be16 protocol;
__u16 transport_header;
__u16 network_header;
__u16 mac_header;
/* private: */
__u32 headers_end[0];
/* public: */
/* These elements must be at the end, see alloc_skb() for details. */
sk_buff_data_t tail;
sk_buff_data_t end;
unsigned char *head,
*data;
unsigned int truesize;
atomic_t users;
};
#ifdef __KERNEL__
/*
* Handling routines are only of interest to the kernel
*/
#include <linux/slab.h>
#define SKB_ALLOC_FCLONE 0x01
#define SKB_ALLOC_RX 0x02
#define SKB_ALLOC_NAPI 0x04
/* Returns true if the skb was allocated from PFMEMALLOC reserves */
static inline bool skb_pfmemalloc(const struct sk_buff *skb)
{
return unlikely(skb->pfmemalloc);
}
/*
* skb might have a dst pointer attached, refcounted or not.
* _skb_refdst low order bit is set if refcount was _not_ taken
*/
#define SKB_DST_NOREF 1UL
#define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
/**
* skb_dst - returns skb dst_entry
* @skb: buffer
*
* Returns skb dst_entry, regardless of reference taken or not.
*/
static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
{
/* If refdst was not refcounted, check we still are in a
* rcu_read_lock section
*/
WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
!rcu_read_lock_held() &&
!rcu_read_lock_bh_held());
return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
}
/**
* skb_dst_set - sets skb dst
* @skb: buffer
* @dst: dst entry
*
* Sets skb dst, assuming a reference was taken on dst and should
* be released by skb_dst_drop()
*/
static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
{
skb->_skb_refdst = (unsigned long)dst;
}
/**
* skb_dst_set_noref - sets skb dst, hopefully, without taking reference
* @skb: buffer
* @dst: dst entry
*
* Sets skb dst, assuming a reference was not taken on dst.
* If dst entry is cached, we do not take reference and dst_release
* will be avoided by refdst_drop. If dst entry is not cached, we take
* reference, so that last dst_release can destroy the dst immediately.
*/
static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
{
WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
}
/**
* skb_dst_is_noref - Test if skb dst isn't refcounted
* @skb: buffer
*/
static inline bool skb_dst_is_noref(const struct sk_buff *skb)
{
return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
}
static inline struct rtable *skb_rtable(const struct sk_buff *skb)
{
return (struct rtable *)skb_dst(skb);
}
/* For mangling skb->pkt_type from user space side from applications
* such as nft, tc, etc, we only allow a conservative subset of
* possible pkt_types to be set.
*/
static inline bool skb_pkt_type_ok(u32 ptype)
{
return ptype <= PACKET_OTHERHOST;
}
void kfree_skb(struct sk_buff *skb);
void kfree_skb_list(struct sk_buff *segs);
void skb_tx_error(struct sk_buff *skb);
void consume_skb(struct sk_buff *skb);
void __kfree_skb(struct sk_buff *skb);
extern struct kmem_cache *skbuff_head_cache;
void kfree_skb_partial(struct sk_buff *skb, bool head_stolen);
bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
bool *fragstolen, int *delta_truesize);
struct sk_buff *__alloc_skb(unsigned int size, gfp_t priority, int flags,
int node);
struct sk_buff *__build_skb(void *data, unsigned int frag_size);
struct sk_buff *build_skb(void *data, unsigned int frag_size);
static inline struct sk_buff *alloc_skb(unsigned int size,
gfp_t priority)
{
return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
}
struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
unsigned long data_len,
int max_page_order,
int *errcode,
gfp_t gfp_mask);
/* Layout of fast clones : [skb1][skb2][fclone_ref] */
struct sk_buff_fclones {
struct sk_buff skb1;
struct sk_buff skb2;
atomic_t fclone_ref;
};
/**
* skb_fclone_busy - check if fclone is busy
* @skb: buffer
*
* Returns true if skb is a fast clone, and its clone is not freed.
* Some drivers call skb_orphan() in their ndo_start_xmit(),
* so we also check that this didnt happen.
*/
static inline bool skb_fclone_busy(const struct sock *sk,
const struct sk_buff *skb)
{
const struct sk_buff_fclones *fclones;
fclones = container_of(skb, struct sk_buff_fclones, skb1);
return skb->fclone == SKB_FCLONE_ORIG &&
atomic_read(&fclones->fclone_ref) > 1 &&
fclones->skb2.sk == sk;
}
static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
gfp_t priority)
{
return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, NUMA_NO_NODE);
}
struct sk_buff *__alloc_skb_head(gfp_t priority, int node);
static inline struct sk_buff *alloc_skb_head(gfp_t priority)
{
return __alloc_skb_head(priority, -1);
}
struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t priority);
struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t priority);
struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
gfp_t gfp_mask, bool fclone);
static inline struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom,
gfp_t gfp_mask)
{
return __pskb_copy_fclone(skb, headroom, gfp_mask, false);
}
int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, gfp_t gfp_mask);
struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
unsigned int headroom);
struct sk_buff *skb_copy_expand(const struct sk_buff *skb, int newheadroom,
int newtailroom, gfp_t priority);
int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
int offset, int len);
int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset,
int len);
int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);
int skb_pad(struct sk_buff *skb, int pad);
#define dev_kfree_skb(a) consume_skb(a)
int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
int getfrag(void *from, char *to, int offset,
int len, int odd, struct sk_buff *skb),
void *from, int length);
int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
int offset, size_t size);
struct skb_seq_state {
__u32 lower_offset;
__u32 upper_offset;
__u32 frag_idx;
__u32 stepped_offset;
struct sk_buff *root_skb;
struct sk_buff *cur_skb;
__u8 *frag_data;
};
void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
unsigned int to, struct skb_seq_state *st);
unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
struct skb_seq_state *st);
void skb_abort_seq_read(struct skb_seq_state *st);
unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
unsigned int to, struct ts_config *config);
/*
* Packet hash types specify the type of hash in skb_set_hash.
*
* Hash types refer to the protocol layer addresses which are used to
* construct a packet's hash. The hashes are used to differentiate or identify
* flows of the protocol layer for the hash type. Hash types are either
* layer-2 (L2), layer-3 (L3), or layer-4 (L4).
*
* Properties of hashes:
*
* 1) Two packets in different flows have different hash values
* 2) Two packets in the same flow should have the same hash value
*
* A hash at a higher layer is considered to be more specific. A driver should
* set the most specific hash possible.
*
* A driver cannot indicate a more specific hash than the layer at which a hash
* was computed. For instance an L3 hash cannot be set as an L4 hash.
*
* A driver may indicate a hash level which is less specific than the
* actual layer the hash was computed on. For instance, a hash computed
* at L4 may be considered an L3 hash. This should only be done if the
* driver can't unambiguously determine that the HW computed the hash at
* the higher layer. Note that the "should" in the second property above
* permits this.
*/
enum pkt_hash_types {
PKT_HASH_TYPE_NONE, /* Undefined type */
PKT_HASH_TYPE_L2, /* Input: src_MAC, dest_MAC */
PKT_HASH_TYPE_L3, /* Input: src_IP, dst_IP */
PKT_HASH_TYPE_L4, /* Input: src_IP, dst_IP, src_port, dst_port */
};
static inline void skb_clear_hash(struct sk_buff *skb)
{
skb->hash = 0;
skb->sw_hash = 0;
skb->l4_hash = 0;
}
static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
{
if (!skb->l4_hash)
skb_clear_hash(skb);
}
static inline void
__skb_set_hash(struct sk_buff *skb, __u32 hash, bool is_sw, bool is_l4)
{
skb->l4_hash = is_l4;
skb->sw_hash = is_sw;
skb->hash = hash;
}
static inline void
skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
{
/* Used by drivers to set hash from HW */
__skb_set_hash(skb, hash, false, type == PKT_HASH_TYPE_L4);
}
static inline void
__skb_set_sw_hash(struct sk_buff *skb, __u32 hash, bool is_l4)
{
__skb_set_hash(skb, hash, true, is_l4);
}
void __skb_get_hash(struct sk_buff *skb);
u32 __skb_get_hash_symmetric(struct sk_buff *skb);
u32 skb_get_poff(const struct sk_buff *skb);
u32 __skb_get_poff(const struct sk_buff *skb, void *data,
const struct flow_keys *keys, int hlen);
__be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
void *data, int hlen_proto);
static inline __be32 skb_flow_get_ports(const struct sk_buff *skb,
int thoff, u8 ip_proto)
{
return __skb_flow_get_ports(skb, thoff, ip_proto, NULL, 0);
}
void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
const struct flow_dissector_key *key,
unsigned int key_count);
bool __skb_flow_dissect(const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
void *target_container,
void *data, __be16 proto, int nhoff, int hlen,
unsigned int flags);
static inline bool skb_flow_dissect(const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
void *target_container, unsigned int flags)
{
return __skb_flow_dissect(skb, flow_dissector, target_container,
NULL, 0, 0, 0, flags);
}
static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb,
struct flow_keys *flow,
unsigned int flags)
{
memset(flow, 0, sizeof(*flow));
return __skb_flow_dissect(skb, &flow_keys_dissector, flow,
NULL, 0, 0, 0, flags);
}
static inline bool skb_flow_dissect_flow_keys_buf(struct flow_keys *flow,
void *data, __be16 proto,
int nhoff, int hlen,
unsigned int flags)
{
memset(flow, 0, sizeof(*flow));
return __skb_flow_dissect(NULL, &flow_keys_buf_dissector, flow,
data, proto, nhoff, hlen, flags);
}
static inline __u32 skb_get_hash(struct sk_buff *skb)
{
if (!skb->l4_hash && !skb->sw_hash)
__skb_get_hash(skb);
return skb->hash;
}
__u32 __skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6);
static inline __u32 skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6)
{
if (!skb->l4_hash && !skb->sw_hash) {
struct flow_keys keys;
__u32 hash = __get_hash_from_flowi6(fl6, &keys);
__skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
}
return skb->hash;
}
__u32 __skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl);
static inline __u32 skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl4)
{
if (!skb->l4_hash && !skb->sw_hash) {
struct flow_keys keys;
__u32 hash = __get_hash_from_flowi4(fl4, &keys);
__skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
}
return skb->hash;
}
__u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb);
static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)
{
return skb->hash;
}
static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
{
to->hash = from->hash;
to->sw_hash = from->sw_hash;
to->l4_hash = from->l4_hash;
};
#ifdef NET_SKBUFF_DATA_USES_OFFSET
static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
{
return skb->head + skb->end;
}
static inline unsigned int skb_end_offset(const struct sk_buff *skb)
{
return skb->end;
}
#else
static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
{
return skb->end;
}
static inline unsigned int skb_end_offset(const struct sk_buff *skb)
{
return skb->end - skb->head;
}
#endif
/* Internal */
#define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
{
return &skb_shinfo(skb)->hwtstamps;
}
/**
* skb_queue_empty - check if a queue is empty
* @list: queue head
*
* Returns true if the queue is empty, false otherwise.
*/
static inline int skb_queue_empty(const struct sk_buff_head *list)
{
return list->next == (const struct sk_buff *) list;
}
/**
* skb_queue_is_last - check if skb is the last entry in the queue
* @list: queue head
* @skb: buffer
*
* Returns true if @skb is the last buffer on the list.
*/
static inline bool skb_queue_is_last(const struct sk_buff_head *list,
const struct sk_buff *skb)
{
return skb->next == (const struct sk_buff *) list;
}
/**
* skb_queue_is_first - check if skb is the first entry in the queue
* @list: queue head
* @skb: buffer
*
* Returns true if @skb is the first buffer on the list.
*/
static inline bool skb_queue_is_first(const struct sk_buff_head *list,
const struct sk_buff *skb)
{
return skb->prev == (const struct sk_buff *) list;
}
/**
* skb_queue_next - return the next packet in the queue
* @list: queue head
* @skb: current buffer
*
* Return the next packet in @list after @skb. It is only valid to
* call this if skb_queue_is_last() evaluates to false.
*/
static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
const struct sk_buff *skb)
{
/* This BUG_ON may seem severe, but if we just return then we
* are going to dereference garbage.
*/
BUG_ON(skb_queue_is_last(list, skb));
return skb->next;
}
/**
* skb_queue_prev - return the prev packet in the queue
* @list: queue head
* @skb: current buffer
*
* Return the prev packet in @list before @skb. It is only valid to
* call this if skb_queue_is_first() evaluates to false.
*/
static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
const struct sk_buff *skb)
{
/* This BUG_ON may seem severe, but if we just return then we
* are going to dereference garbage.
*/
BUG_ON(skb_queue_is_first(list, skb));
return skb->prev;
}
/**
* skb_get - reference buffer
* @skb: buffer to reference
*
* Makes another reference to a socket buffer and returns a pointer
* to the buffer.
*/
static inline struct sk_buff *skb_get(struct sk_buff *skb)
{
atomic_inc(&skb->users);
return skb;
}
/*
* If users == 1, we are the only owner and are can avoid redundant
* atomic change.
*/
/**
* skb_cloned - is the buffer a clone
* @skb: buffer to check
*
* Returns true if the buffer was generated with skb_clone() and is
* one of multiple shared copies of the buffer. Cloned buffers are
* shared data so must not be written to under normal circumstances.
*/
static inline int skb_cloned(const struct sk_buff *skb)
{
return skb->cloned &&
(atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
}
static inline int skb_unclone(struct sk_buff *skb, gfp_t pri)
{
might_sleep_if(gfpflags_allow_blocking(pri));
if (skb_cloned(skb))
return pskb_expand_head(skb, 0, 0, pri);
return 0;
}
/**
* skb_header_cloned - is the header a clone
* @skb: buffer to check
*
* Returns true if modifying the header part of the buffer requires
* the data to be copied.
*/
static inline int skb_header_cloned(const struct sk_buff *skb)
{
int dataref;
if (!skb->cloned)
return 0;
dataref = atomic_read(&skb_shinfo(skb)->dataref);
dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
return dataref != 1;
}
static inline int skb_header_unclone(struct sk_buff *skb, gfp_t pri)
{
might_sleep_if(gfpflags_allow_blocking(pri));
if (skb_header_cloned(skb))
return pskb_expand_head(skb, 0, 0, pri);
return 0;
}
/**
* skb_header_release - release reference to header
* @skb: buffer to operate on
*
* Drop a reference to the header part of the buffer. This is done
* by acquiring a payload reference. You must not read from the header
* part of skb->data after this.
* Note : Check if you can use __skb_header_release() instead.
*/
static inline void skb_header_release(struct sk_buff *skb)
{
BUG_ON(skb->nohdr);
skb->nohdr = 1;
atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
}
/**
* __skb_header_release - release reference to header
* @skb: buffer to operate on
*
* Variant of skb_header_release() assuming skb is private to caller.
* We can avoid one atomic operation.
*/
static inline void __skb_header_release(struct sk_buff *skb)
{
skb->nohdr = 1;
atomic_set(&skb_shinfo(skb)->dataref, 1 + (1 << SKB_DATAREF_SHIFT));
}
/**
* skb_shared - is the buffer shared
* @skb: buffer to check
*
* Returns true if more than one person has a reference to this
* buffer.
*/
static inline int skb_shared(const struct sk_buff *skb)
{
return atomic_read(&skb->users) != 1;
}
/**
* skb_share_check - check if buffer is shared and if so clone it
* @skb: buffer to check
* @pri: priority for memory allocation
*
* If the buffer is shared the buffer is cloned and the old copy
* drops a reference. A new clone with a single reference is returned.
* If the buffer is not shared the original buffer is returned. When
* being called from interrupt status or with spinlocks held pri must
* be GFP_ATOMIC.
*
* NULL is returned on a memory allocation failure.
*/
static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
{
might_sleep_if(gfpflags_allow_blocking(pri));
if (skb_shared(skb)) {
struct sk_buff *nskb = skb_clone(skb, pri);
if (likely(nskb))
consume_skb(skb);
else
kfree_skb(skb);
skb = nskb;
}
return skb;
}
/*
* Copy shared buffers into a new sk_buff. We effectively do COW on
* packets to handle cases where we have a local reader and forward
* and a couple of other messy ones. The normal one is tcpdumping
* a packet thats being forwarded.
*/
/**
* skb_unshare - make a copy of a shared buffer
* @skb: buffer to check
* @pri: priority for memory allocation
*
* If the socket buffer is a clone then this function creates a new
* copy of the data, drops a reference count on the old copy and returns
* the new copy with the reference count at 1. If the buffer is not a clone
* the original buffer is returned. When called with a spinlock held or
* from interrupt state @pri must be %GFP_ATOMIC
*
* %NULL is returned on a memory allocation failure.
*/
static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
gfp_t pri)
{
might_sleep_if(gfpflags_allow_blocking(pri));
if (skb_cloned(skb)) {
struct sk_buff *nskb = skb_copy(skb, pri);
/* Free our shared copy */
if (likely(nskb))
consume_skb(skb);
else
kfree_skb(skb);
skb = nskb;
}
return skb;
}
/**
* skb_peek - peek at the head of an &sk_buff_head
* @list_: list to peek at
*
* Peek an &sk_buff. Unlike most other operations you _MUST_
* be careful with this one. A peek leaves the buffer on the
* list and someone else may run off with it. You must hold
* the appropriate locks or have a private queue to do this.
*
* Returns %NULL for an empty list or a pointer to the head element.
* The reference count is not incremented and the reference is therefore
* volatile. Use with caution.
*/
static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
{
struct sk_buff *skb = list_->next;
if (skb == (struct sk_buff *)list_)
skb = NULL;
return skb;
}
/**
* skb_peek_next - peek skb following the given one from a queue
* @skb: skb to start from
* @list_: list to peek at
*
* Returns %NULL when the end of the list is met or a pointer to the
* next element. The reference count is not incremented and the
* reference is therefore volatile. Use with caution.
*/
static inline struct sk_buff *skb_peek_next(struct sk_buff *skb,
const struct sk_buff_head *list_)
{
struct sk_buff *next = skb->next;
if (next == (struct sk_buff *)list_)
next = NULL;
return next;
}
/**
* skb_peek_tail - peek at the tail of an &sk_buff_head
* @list_: list to peek at
*
* Peek an &sk_buff. Unlike most other operations you _MUST_
* be careful with this one. A peek leaves the buffer on the
* list and someone else may run off with it. You must hold
* the appropriate locks or have a private queue to do this.
*
* Returns %NULL for an empty list or a pointer to the tail element.
* The reference count is not incremented and the reference is therefore
* volatile. Use with caution.
*/
static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
{
struct sk_buff *skb = list_->prev;
if (skb == (struct sk_buff *)list_)
skb = NULL;
return skb;
}
/**
* skb_queue_len - get queue length
* @list_: list to measure
*
* Return the length of an &sk_buff queue.
*/
static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
{
return list_->qlen;
}
/**
* __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
* @list: queue to initialize
*
* This initializes only the list and queue length aspects of
* an sk_buff_head object. This allows to initialize the list
* aspects of an sk_buff_head without reinitializing things like
* the spinlock. It can also be used for on-stack sk_buff_head
* objects where the spinlock is known to not be used.
*/
static inline void __skb_queue_head_init(struct sk_buff_head *list)
{
list->prev = list->next = (struct sk_buff *)list;
list->qlen = 0;
}
/*
* This function creates a split out lock class for each invocation;
* this is needed for now since a whole lot of users of the skb-queue
* infrastructure in drivers have different locking usage (in hardirq)
* than the networking core (in softirq only). In the long run either the
* network layer or drivers should need annotation to consolidate the
* main types of usage into 3 classes.
*/
static inline void skb_queue_head_init(struct sk_buff_head *list)
{
spin_lock_init(&list->lock);
__skb_queue_head_init(list);
}
static inline void skb_queue_head_init_class(struct sk_buff_head *list,
struct lock_class_key *class)
{
skb_queue_head_init(list);
lockdep_set_class(&list->lock, class);
}
/*
* Insert an sk_buff on a list.
*
* The "__skb_xxxx()" functions are the non-atomic ones that
* can only be called with interrupts disabled.
*/
void skb_insert(struct sk_buff *old, struct sk_buff *newsk,
struct sk_buff_head *list);
static inline void __skb_insert(struct sk_buff *newsk,
struct sk_buff *prev, struct sk_buff *next,
struct sk_buff_head *list)
{
newsk->next = next;
newsk->prev = prev;
next->prev = prev->next = newsk;
list->qlen++;
}
static inline void __skb_queue_splice(const struct sk_buff_head *list,
struct sk_buff *prev,
struct sk_buff *next)
{
struct sk_buff *first = list->next;
struct sk_buff *last = list->prev;
first->prev = prev;
prev->next = first;
last->next = next;
next->prev = last;
}
/**
* skb_queue_splice - join two skb lists, this is designed for stacks
* @list: the new list to add
* @head: the place to add it in the first list
*/
static inline void skb_queue_splice(const struct sk_buff_head *list,
struct sk_buff_head *head)
{
if (!skb_queue_empty(list)) {
__skb_queue_splice(list, (struct sk_buff *) head, head->next);
head->qlen += list->qlen;
}
}
/**
* skb_queue_splice_init - join two skb lists and reinitialise the emptied list
* @list: the new list to add
* @head: the place to add it in the first list
*
* The list at @list is reinitialised
*/
static inline void skb_queue_splice_init(struct sk_buff_head *list,
struct sk_buff_head *head)
{
if (!skb_queue_empty(list)) {
__skb_queue_splice(list, (struct sk_buff *) head, head->next);
head->qlen += list->qlen;
__skb_queue_head_init(list);
}
}
/**
* skb_queue_splice_tail - join two skb lists, each list being a queue
* @list: the new list to add
* @head: the place to add it in the first list
*/
static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
struct sk_buff_head *head)
{
if (!skb_queue_empty(list)) {
__skb_queue_splice(list, head->prev, (struct sk_buff *) head);
head->qlen += list->qlen;
}
}
/**
* skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list
* @list: the new list to add
* @head: the place to add it in the first list
*
* Each of the lists is a queue.
* The list at @list is reinitialised
*/
static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
struct sk_buff_head *head)
{
if (!skb_queue_empty(list)) {
__skb_queue_splice(list, head->prev, (struct sk_buff *) head);
head->qlen += list->qlen;
__skb_queue_head_init(list);
}
}
/**
* __skb_queue_after - queue a buffer at the list head
* @list: list to use
* @prev: place after this buffer
* @newsk: buffer to queue
*
* Queue a buffer int the middle of a list. This function takes no locks
* and you must therefore hold required locks before calling it.
*
* A buffer cannot be placed on two lists at the same time.
*/
static inline void __skb_queue_after(struct sk_buff_head *list,
struct sk_buff *prev,
struct sk_buff *newsk)
{
__skb_insert(newsk, prev, prev->next, list);
}
void skb_append(struct sk_buff *old, struct sk_buff *newsk,
struct sk_buff_head *list);
static inline void __skb_queue_before(struct sk_buff_head *list,
struct sk_buff *next,
struct sk_buff *newsk)
{
__skb_insert(newsk, next->prev, next, list);
}
/**
* __skb_queue_head - queue a buffer at the list head
* @list: list to use
* @newsk: buffer to queue
*
* Queue a buffer at the start of a list. This function takes no locks
* and you must therefore hold required locks before calling it.
*
* A buffer cannot be placed on two lists at the same time.
*/
void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
static inline void __skb_queue_head(struct sk_buff_head *list,
struct sk_buff *newsk)
{
__skb_queue_after(list, (struct sk_buff *)list, newsk);
}
/**
* __skb_queue_tail - queue a buffer at the list tail
* @list: list to use
* @newsk: buffer to queue
*
* Queue a buffer at the end of a list. This function takes no locks
* and you must therefore hold required locks before calling it.
*
* A buffer cannot be placed on two lists at the same time.
*/
void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
static inline void __skb_queue_tail(struct sk_buff_head *list,
struct sk_buff *newsk)
{
__skb_queue_before(list, (struct sk_buff *)list, newsk);
}
/*
* remove sk_buff from list. _Must_ be called atomically, and with
* the list known..
*/
void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
{
struct sk_buff *next, *prev;
list->qlen--;
next = skb->next;
prev = skb->prev;
skb->next = skb->prev = NULL;
next->prev = prev;
prev->next = next;
}
/**
* __skb_dequeue - remove from the head of the queue
* @list: list to dequeue from
*
* Remove the head of the list. This function does not take any locks
* so must be used with appropriate locks held only. The head item is
* returned or %NULL if the list is empty.
*/
struct sk_buff *skb_dequeue(struct sk_buff_head *list);
static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
{
struct sk_buff *skb = skb_peek(list);
if (skb)
__skb_unlink(skb, list);
return skb;
}
/**
* __skb_dequeue_tail - remove from the tail of the queue
* @list: list to dequeue from
*
* Remove the tail of the list. This function does not take any locks
* so must be used with appropriate locks held only. The tail item is
* returned or %NULL if the list is empty.
*/
struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
{
struct sk_buff *skb = skb_peek_tail(list);
if (skb)
__skb_unlink(skb, list);
return skb;
}
static inline bool skb_is_nonlinear(const struct sk_buff *skb)
{
return skb->data_len;
}
static inline unsigned int skb_headlen(const struct sk_buff *skb)
{
return skb->len - skb->data_len;
}
static inline int skb_pagelen(const struct sk_buff *skb)
{
int i, len = 0;
for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
return len + skb_headlen(skb);
}
/**
* __skb_fill_page_desc - initialise a paged fragment in an skb
* @skb: buffer containing fragment to be initialised
* @i: paged fragment index to initialise
* @page: the page to use for this fragment
* @off: the offset to the data with @page
* @size: the length of the data
*
* Initialises the @i'th fragment of @skb to point to &size bytes at
* offset @off within @page.
*
* Does not take any additional reference on the fragment.
*/
static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
struct page *page, int off, int size)
{
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
/*
* Propagate page pfmemalloc to the skb if we can. The problem is
* that not all callers have unique ownership of the page but rely
* on page_is_pfmemalloc doing the right thing(tm).
*/
frag->page.p = page;
frag->page_offset = off;
skb_frag_size_set(frag, size);
page = compound_head(page);
if (page_is_pfmemalloc(page))
skb->pfmemalloc = true;
}
/**
* skb_fill_page_desc - initialise a paged fragment in an skb
* @skb: buffer containing fragment to be initialised
* @i: paged fragment index to initialise
* @page: the page to use for this fragment
* @off: the offset to the data with @page
* @size: the length of the data
*
* As per __skb_fill_page_desc() -- initialises the @i'th fragment of
* @skb to point to @size bytes at offset @off within @page. In
* addition updates @skb such that @i is the last fragment.
*
* Does not take any additional reference on the fragment.
*/
static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
struct page *page, int off, int size)
{
__skb_fill_page_desc(skb, i, page, off, size);
skb_shinfo(skb)->nr_frags = i + 1;
}
void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
int size, unsigned int truesize);
void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
unsigned int truesize);
#define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
#define SKB_FRAG_ASSERT(skb) BUG_ON(skb_has_frag_list(skb))
#define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
#ifdef NET_SKBUFF_DATA_USES_OFFSET
static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
{
return skb->head + skb->tail;
}
static inline void skb_reset_tail_pointer(struct sk_buff *skb)
{
skb->tail = skb->data - skb->head;
}
static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
{
skb_reset_tail_pointer(skb);
skb->tail += offset;
}
#else /* NET_SKBUFF_DATA_USES_OFFSET */
static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
{
return skb->tail;
}
static inline void skb_reset_tail_pointer(struct sk_buff *skb)
{
skb->tail = skb->data;
}
static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
{
skb->tail = skb->data + offset;
}
#endif /* NET_SKBUFF_DATA_USES_OFFSET */
/*
* Add data to an sk_buff
*/
unsigned char *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);
unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
{
unsigned char *tmp = skb_tail_pointer(skb);
SKB_LINEAR_ASSERT(skb);
skb->tail += len;
skb->len += len;
return tmp;
}
unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
{
skb->data -= len;
skb->len += len;
return skb->data;
}
unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
{
skb->len -= len;
BUG_ON(skb->len < skb->data_len);
return skb->data += len;
}
static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
{
return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
}
unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
{
if (len > skb_headlen(skb) &&
!__pskb_pull_tail(skb, len - skb_headlen(skb)))
return NULL;
skb->len -= len;
return skb->data += len;
}
static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
{
return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
}
static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
{
if (likely(len <= skb_headlen(skb)))
return 1;
if (unlikely(len > skb->len))
return 0;
return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
}
/**
* skb_headroom - bytes at buffer head
* @skb: buffer to check
*
* Return the number of bytes of free space at the head of an &sk_buff.
*/
static inline unsigned int skb_headroom(const struct sk_buff *skb)
{
return skb->data - skb->head;
}
/**
* skb_tailroom - bytes at buffer end
* @skb: buffer to check
*
* Return the number of bytes of free space at the tail of an sk_buff
*/
static inline int skb_tailroom(const struct sk_buff *skb)
{
return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
}
/**
* skb_availroom - bytes at buffer end
* @skb: buffer to check
*
* Return the number of bytes of free space at the tail of an sk_buff
* allocated by sk_stream_alloc()
*/
static inline int skb_availroom(const struct sk_buff *skb)
{
if (skb_is_nonlinear(skb))
return 0;
return skb->end - skb->tail - skb->reserved_tailroom;
}
/**
* skb_reserve - adjust headroom
* @skb: buffer to alter
* @len: bytes to move
*
* Increase the headroom of an empty &sk_buff by reducing the tail
* room. This is only allowed for an empty buffer.
*/
static inline void skb_reserve(struct sk_buff *skb, int len)
{
skb->data += len;
skb->tail += len;
}
/**
* skb_tailroom_reserve - adjust reserved_tailroom
* @skb: buffer to alter
* @mtu: maximum amount of headlen permitted
* @needed_tailroom: minimum amount of reserved_tailroom
*
* Set reserved_tailroom so that headlen can be as large as possible but
* not larger than mtu and tailroom cannot be smaller than
* needed_tailroom.
* The required headroom should already have been reserved before using
* this function.
*/
static inline void skb_tailroom_reserve(struct sk_buff *skb, unsigned int mtu,
unsigned int needed_tailroom)
{
SKB_LINEAR_ASSERT(skb);
if (mtu < skb_tailroom(skb) - needed_tailroom)
/* use at most mtu */
skb->reserved_tailroom = skb_tailroom(skb) - mtu;
else
/* use up to all available space */
skb->reserved_tailroom = needed_tailroom;
}
#define ENCAP_TYPE_ETHER 0
#define ENCAP_TYPE_IPPROTO 1
static inline void skb_set_inner_protocol(struct sk_buff *skb,
__be16 protocol)
{
skb->inner_protocol = protocol;
skb->inner_protocol_type = ENCAP_TYPE_ETHER;
}
static inline void skb_set_inner_ipproto(struct sk_buff *skb,
__u8 ipproto)
{
skb->inner_ipproto = ipproto;
skb->inner_protocol_type = ENCAP_TYPE_IPPROTO;
}
static inline void skb_reset_inner_headers(struct sk_buff *skb)
{
skb->inner_mac_header = skb->mac_header;
skb->inner_network_header = skb->network_header;
skb->inner_transport_header = skb->transport_header;
}
static inline void skb_reset_mac_len(struct sk_buff *skb)
{
skb->mac_len = skb->network_header - skb->mac_header;
}
static inline unsigned char *skb_inner_transport_header(const struct sk_buff
*skb)
{
return skb->head + skb->inner_transport_header;
}
static inline int skb_inner_transport_offset(const struct sk_buff *skb)
{
return skb_inner_transport_header(skb) - skb->data;
}
static inline void skb_reset_inner_transport_header(struct sk_buff *skb)
{
skb->inner_transport_header = skb->data - skb->head;
}
static inline void skb_set_inner_transport_header(struct sk_buff *skb,
const int offset)
{
skb_reset_inner_transport_header(skb);
skb->inner_transport_header += offset;
}
static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb)
{
return skb->head + skb->inner_network_header;
}
static inline void skb_reset_inner_network_header(struct sk_buff *skb)
{
skb->inner_network_header = skb->data - skb->head;
}
static inline void skb_set_inner_network_header(struct sk_buff *skb,
const int offset)
{
skb_reset_inner_network_header(skb);
skb->inner_network_header += offset;
}
static inline unsigned char *skb_inner_mac_header(const struct sk_buff *skb)
{
return skb->head + skb->inner_mac_header;
}
static inline void skb_reset_inner_mac_header(struct sk_buff *skb)
{
skb->inner_mac_header = skb->data - skb->head;
}
static inline void skb_set_inner_mac_header(struct sk_buff *skb,
const int offset)
{
skb_reset_inner_mac_header(skb);
skb->inner_mac_header += offset;
}
static inline bool skb_transport_header_was_set(const struct sk_buff *skb)
{
return skb->transport_header != (typeof(skb->transport_header))~0U;
}
static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
{
return skb->head + skb->transport_header;
}
static inline void skb_reset_transport_header(struct sk_buff *skb)
{
skb->transport_header = skb->data - skb->head;
}
static inline void skb_set_transport_header(struct sk_buff *skb,
const int offset)
{
skb_reset_transport_header(skb);
skb->transport_header += offset;
}
static inline unsigned char *skb_network_header(const struct sk_buff *skb)
{
return skb->head + skb->network_header;
}
static inline void skb_reset_network_header(struct sk_buff *skb)
{
skb->network_header = skb->data - skb->head;
}
static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
{
skb_reset_network_header(skb);
skb->network_header += offset;
}
static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
{
return skb->head + skb->mac_header;
}
static inline int skb_mac_header_was_set(const struct sk_buff *skb)
{
return skb->mac_header != (typeof(skb->mac_header))~0U;
}
static inline void skb_reset_mac_header(struct sk_buff *skb)
{
skb->mac_header = skb->data - skb->head;
}
static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
{
skb_reset_mac_header(skb);
skb->mac_header += offset;
}
static inline void skb_pop_mac_header(struct sk_buff *skb)
{
skb->mac_header = skb->network_header;
}
static inline void skb_probe_transport_header(struct sk_buff *skb,
const int offset_hint)
{
struct flow_keys keys;
if (skb_transport_header_was_set(skb))
return;
else if (skb_flow_dissect_flow_keys(skb, &keys, 0))
skb_set_transport_header(skb, keys.control.thoff);
else
skb_set_transport_header(skb, offset_hint);
}
static inline void skb_mac_header_rebuild(struct sk_buff *skb)
{
if (skb_mac_header_was_set(skb)) {
const unsigned char *old_mac = skb_mac_header(skb);
skb_set_mac_header(skb, -skb->mac_len);
memmove(skb_mac_header(skb), old_mac, skb->mac_len);
}
}
static inline int skb_checksum_start_offset(const struct sk_buff *skb)
{
return skb->csum_start - skb_headroom(skb);
}
static inline unsigned char *skb_checksum_start(const struct sk_buff *skb)
{
return skb->head + skb->csum_start;
}
static inline int skb_transport_offset(const struct sk_buff *skb)
{
return skb_transport_header(skb) - skb->data;
}
static inline u32 skb_network_header_len(const struct sk_buff *skb)
{
return skb->transport_header - skb->network_header;
}
static inline u32 skb_inner_network_header_len(const struct sk_buff *skb)
{
return skb->inner_transport_header - skb->inner_network_header;
}
static inline int skb_network_offset(const struct sk_buff *skb)
{
return skb_network_header(skb) - skb->data;
}
static inline int skb_inner_network_offset(const struct sk_buff *skb)
{
return skb_inner_network_header(skb) - skb->data;
}
static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
{
return pskb_may_pull(skb, skb_network_offset(skb) + len);
}
/*
* CPUs often take a performance hit when accessing unaligned memory
* locations. The actual performance hit varies, it can be small if the
* hardware handles it or large if we have to take an exception and fix it
* in software.
*
* Since an ethernet header is 14 bytes network drivers often end up with
* the IP header at an unaligned offset. The IP header can be aligned by
* shifting the start of the packet by 2 bytes. Drivers should do this
* with:
*
* skb_reserve(skb, NET_IP_ALIGN);
*
* The downside to this alignment of the IP header is that the DMA is now
* unaligned. On some architectures the cost of an unaligned DMA is high
* and this cost outweighs the gains made by aligning the IP header.
*
* Since this trade off varies between architectures, we allow NET_IP_ALIGN
* to be overridden.
*/
#ifndef NET_IP_ALIGN
#define NET_IP_ALIGN 2
#endif
/*
* The networking layer reserves some headroom in skb data (via
* dev_alloc_skb). This is used to avoid having to reallocate skb data when
* the header has to grow. In the default case, if the header has to grow
* 32 bytes or less we avoid the reallocation.
*
* Unfortunately this headroom changes the DMA alignment of the resulting
* network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
* on some architectures. An architecture can override this value,
* perhaps setting it to a cacheline in size (since that will maintain
* cacheline alignment of the DMA). It must be a power of 2.
*
* Various parts of the networking layer expect at least 32 bytes of
* headroom, you should not reduce this.
*
* Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
* to reduce average number of cache lines per packet.
* get_rps_cpus() for example only access one 64 bytes aligned block :
* NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
*/
#ifndef NET_SKB_PAD
#define NET_SKB_PAD max(32, L1_CACHE_BYTES)
#endif
int ___pskb_trim(struct sk_buff *skb, unsigned int len);
static inline void __skb_set_length(struct sk_buff *skb, unsigned int len)
{
if (unlikely(skb_is_nonlinear(skb))) {
WARN_ON(1);
return;
}
skb->len = len;
skb_set_tail_pointer(skb, len);
}
static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
{
__skb_set_length(skb, len);
}
void skb_trim(struct sk_buff *skb, unsigned int len);
static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
{
if (skb->data_len)
return ___pskb_trim(skb, len);
__skb_trim(skb, len);
return 0;
}
static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
{
return (len < skb->len) ? __pskb_trim(skb, len) : 0;
}
/**
* pskb_trim_unique - remove end from a paged unique (not cloned) buffer
* @skb: buffer to alter
* @len: new length
*
* This is identical to pskb_trim except that the caller knows that
* the skb is not cloned so we should never get an error due to out-
* of-memory.
*/
static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
{
int err = pskb_trim(skb, len);
BUG_ON(err);
}
static inline int __skb_grow(struct sk_buff *skb, unsigned int len)
{
unsigned int diff = len - skb->len;
if (skb_tailroom(skb) < diff) {
int ret = pskb_expand_head(skb, 0, diff - skb_tailroom(skb),
GFP_ATOMIC);
if (ret)
return ret;
}
__skb_set_length(skb, len);
return 0;
}
/**
* skb_orphan - orphan a buffer
* @skb: buffer to orphan
*
* If a buffer currently has an owner then we call the owner's
* destructor function and make the @skb unowned. The buffer continues
* to exist but is no longer charged to its former owner.
*/
static inline void skb_orphan(struct sk_buff *skb)
{
if (skb->destructor) {
skb->destructor(skb);
skb->destructor = NULL;
skb->sk = NULL;
} else {
BUG_ON(skb->sk);
}
}
/**
* skb_orphan_frags - orphan the frags contained in a buffer
* @skb: buffer to orphan frags from
* @gfp_mask: allocation mask for replacement pages
*
* For each frag in the SKB which needs a destructor (i.e. has an
* owner) create a copy of that frag and release the original
* page by calling the destructor.
*/
static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
{
if (likely(!(skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)))
return 0;
return skb_copy_ubufs(skb, gfp_mask);
}
/**
* __skb_queue_purge - empty a list
* @list: list to empty
*
* Delete all buffers on an &sk_buff list. Each buffer is removed from
* the list and one reference dropped. This function does not take the
* list lock and the caller must hold the relevant locks to use it.
*/
void skb_queue_purge(struct sk_buff_head *list);
static inline void __skb_queue_purge(struct sk_buff_head *list)
{
struct sk_buff *skb;
while ((skb = __skb_dequeue(list)) != NULL)
kfree_skb(skb);
}
void *netdev_alloc_frag(unsigned int fragsz);
struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int length,
gfp_t gfp_mask);
/**
* netdev_alloc_skb - allocate an skbuff for rx on a specific device
* @dev: network device to receive on
* @length: length to allocate
*
* Allocate a new &sk_buff and assign it a usage count of one. The
* buffer has unspecified headroom built in. Users should allocate
* the headroom they think they need without accounting for the
* built in space. The built in space is used for optimisations.
*
* %NULL is returned if there is no free memory. Although this function
* allocates memory it can be called from an interrupt.
*/
static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
unsigned int length)
{
return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
}
/* legacy helper around __netdev_alloc_skb() */
static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
gfp_t gfp_mask)
{
return __netdev_alloc_skb(NULL, length, gfp_mask);
}
/* legacy helper around netdev_alloc_skb() */
static inline struct sk_buff *dev_alloc_skb(unsigned int length)
{
return netdev_alloc_skb(NULL, length);
}
static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
unsigned int length, gfp_t gfp)
{
struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
if (NET_IP_ALIGN && skb)
skb_reserve(skb, NET_IP_ALIGN);
return skb;
}
static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
unsigned int length)
{
return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
}
static inline void skb_free_frag(void *addr)
{
__free_page_frag(addr);
}
void *napi_alloc_frag(unsigned int fragsz);
struct sk_buff *__napi_alloc_skb(struct napi_struct *napi,
unsigned int length, gfp_t gfp_mask);
static inline struct sk_buff *napi_alloc_skb(struct napi_struct *napi,
unsigned int length)
{
return __napi_alloc_skb(napi, length, GFP_ATOMIC);
}
void napi_consume_skb(struct sk_buff *skb, int budget);
void __kfree_skb_flush(void);
void __kfree_skb_defer(struct sk_buff *skb);
/**
* __dev_alloc_pages - allocate page for network Rx
* @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
* @order: size of the allocation
*
* Allocate a new page.
*
* %NULL is returned if there is no free memory.
*/
static inline struct page *__dev_alloc_pages(gfp_t gfp_mask,
unsigned int order)
{
/* This piece of code contains several assumptions.
* 1. This is for device Rx, therefor a cold page is preferred.
* 2. The expectation is the user wants a compound page.
* 3. If requesting a order 0 page it will not be compound
* due to the check to see if order has a value in prep_new_page
* 4. __GFP_MEMALLOC is ignored if __GFP_NOMEMALLOC is set due to
* code in gfp_to_alloc_flags that should be enforcing this.
*/
gfp_mask |= __GFP_COLD | __GFP_COMP | __GFP_MEMALLOC;
return alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
}
static inline struct page *dev_alloc_pages(unsigned int order)
{
return __dev_alloc_pages(GFP_ATOMIC | __GFP_NOWARN, order);
}
/**
* __dev_alloc_page - allocate a page for network Rx
* @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
*
* Allocate a new page.
*
* %NULL is returned if there is no free memory.
*/
static inline struct page *__dev_alloc_page(gfp_t gfp_mask)
{
return __dev_alloc_pages(gfp_mask, 0);
}
static inline struct page *dev_alloc_page(void)
{
return dev_alloc_pages(0);
}
/**
* skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
* @page: The page that was allocated from skb_alloc_page
* @skb: The skb that may need pfmemalloc set
*/
static inline void skb_propagate_pfmemalloc(struct page *page,
struct sk_buff *skb)
{
if (page_is_pfmemalloc(page))
skb->pfmemalloc = true;
}
/**
* skb_frag_page - retrieve the page referred to by a paged fragment
* @frag: the paged fragment
*
* Returns the &struct page associated with @frag.
*/
static inline struct page *skb_frag_page(const skb_frag_t *frag)
{
return frag->page.p;
}
/**
* __skb_frag_ref - take an addition reference on a paged fragment.
* @frag: the paged fragment
*
* Takes an additional reference on the paged fragment @frag.
*/
static inline void __skb_frag_ref(skb_frag_t *frag)
{
get_page(skb_frag_page(frag));
}
/**
* skb_frag_ref - take an addition reference on a paged fragment of an skb.
* @skb: the buffer
* @f: the fragment offset.
*
* Takes an additional reference on the @f'th paged fragment of @skb.
*/
static inline void skb_frag_ref(struct sk_buff *skb, int f)
{
__skb_frag_ref(&skb_shinfo(skb)->frags[f]);
}
/**
* __skb_frag_unref - release a reference on a paged fragment.
* @frag: the paged fragment
*
* Releases a reference on the paged fragment @frag.
*/
static inline void __skb_frag_unref(skb_frag_t *frag)
{
put_page(skb_frag_page(frag));
}
/**
* skb_frag_unref - release a reference on a paged fragment of an skb.
* @skb: the buffer
* @f: the fragment offset
*
* Releases a reference on the @f'th paged fragment of @skb.
*/
static inline void skb_frag_unref(struct sk_buff *skb, int f)
{
__skb_frag_unref(&skb_shinfo(skb)->frags[f]);
}
/**
* skb_frag_address - gets the address of the data contained in a paged fragment
* @frag: the paged fragment buffer
*
* Returns the address of the data within @frag. The page must already
* be mapped.
*/
static inline void *skb_frag_address(const skb_frag_t *frag)
{
return page_address(skb_frag_page(frag)) + frag->page_offset;
}
/**
* skb_frag_address_safe - gets the address of the data contained in a paged fragment
* @frag: the paged fragment buffer
*
* Returns the address of the data within @frag. Checks that the page
* is mapped and returns %NULL otherwise.
*/
static inline void *skb_frag_address_safe(const skb_frag_t *frag)
{
void *ptr = page_address(skb_frag_page(frag));
if (unlikely(!ptr))
return NULL;
return ptr + frag->page_offset;
}
/**
* __skb_frag_set_page - sets the page contained in a paged fragment
* @frag: the paged fragment
* @page: the page to set
*
* Sets the fragment @frag to contain @page.
*/
static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
{
frag->page.p = page;
}
/**
* skb_frag_set_page - sets the page contained in a paged fragment of an skb
* @skb: the buffer
* @f: the fragment offset
* @page: the page to set
*
* Sets the @f'th fragment of @skb to contain @page.
*/
static inline void skb_frag_set_page(struct sk_buff *skb, int f,
struct page *page)
{
__skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
}
bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t prio);
/**
* skb_frag_dma_map - maps a paged fragment via the DMA API
* @dev: the device to map the fragment to
* @frag: the paged fragment to map
* @offset: the offset within the fragment (starting at the
* fragment's own offset)
* @size: the number of bytes to map
* @dir: the direction of the mapping (%PCI_DMA_*)
*
* Maps the page associated with @frag to @device.
*/
static inline dma_addr_t skb_frag_dma_map(struct device *dev,
const skb_frag_t *frag,
size_t offset, size_t size,
enum dma_data_direction dir)
{
return dma_map_page(dev, skb_frag_page(frag),
frag->page_offset + offset, size, dir);
}
static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
gfp_t gfp_mask)
{
return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
}
static inline struct sk_buff *pskb_copy_for_clone(struct sk_buff *skb,
gfp_t gfp_mask)
{
return __pskb_copy_fclone(skb, skb_headroom(skb), gfp_mask, true);
}
/**
* skb_clone_writable - is the header of a clone writable
* @skb: buffer to check
* @len: length up to which to write
*
* Returns true if modifying the header part of the cloned buffer
* does not requires the data to be copied.
*/
static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
{
return !skb_header_cloned(skb) &&
skb_headroom(skb) + len <= skb->hdr_len;
}
static inline int skb_try_make_writable(struct sk_buff *skb,
unsigned int write_len)
{
return skb_cloned(skb) && !skb_clone_writable(skb, write_len) &&
pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
}
static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
int cloned)
{
int delta = 0;
if (headroom > skb_headroom(skb))
delta = headroom - skb_headroom(skb);
if (delta || cloned)
return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
GFP_ATOMIC);
return 0;
}
/**
* skb_cow - copy header of skb when it is required
* @skb: buffer to cow
* @headroom: needed headroom
*
* If the skb passed lacks sufficient headroom or its data part
* is shared, data is reallocated. If reallocation fails, an error
* is returned and original skb is not changed.
*
* The result is skb with writable area skb->head...skb->tail
* and at least @headroom of space at head.
*/
static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
{
return __skb_cow(skb, headroom, skb_cloned(skb));
}
/**
* skb_cow_head - skb_cow but only making the head writable
* @skb: buffer to cow
* @headroom: needed headroom
*
* This function is identical to skb_cow except that we replace the
* skb_cloned check by skb_header_cloned. It should be used when
* you only need to push on some header and do not need to modify
* the data.
*/
static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
{
return __skb_cow(skb, headroom, skb_header_cloned(skb));
}
/**
* skb_padto - pad an skbuff up to a minimal size
* @skb: buffer to pad
* @len: minimal length
*
* Pads up a buffer to ensure the trailing bytes exist and are
* blanked. If the buffer already contains sufficient data it
* is untouched. Otherwise it is extended. Returns zero on
* success. The skb is freed on error.
*/
static inline int skb_padto(struct sk_buff *skb, unsigned int len)
{
unsigned int size = skb->len;
if (likely(size >= len))
return 0;
return skb_pad(skb, len - size);
}
/**
* skb_put_padto - increase size and pad an skbuff up to a minimal size
* @skb: buffer to pad
* @len: minimal length
*
* Pads up a buffer to ensure the trailing bytes exist and are
* blanked. If the buffer already contains sufficient data it
* is untouched. Otherwise it is extended. Returns zero on
* success. The skb is freed on error.
*/
static inline int skb_put_padto(struct sk_buff *skb, unsigned int len)
{
unsigned int size = skb->len;
if (unlikely(size < len)) {
len -= size;
if (skb_pad(skb, len))
return -ENOMEM;
__skb_put(skb, len);
}
return 0;
}
static inline int skb_add_data(struct sk_buff *skb,
struct iov_iter *from, int copy)
{
const int off = skb->len;
if (skb->ip_summed == CHECKSUM_NONE) {
__wsum csum = 0;
if (csum_and_copy_from_iter(skb_put(skb, copy), copy,
&csum, from) == copy) {
skb->csum = csum_block_add(skb->csum, csum, off);
return 0;
}
} else if (copy_from_iter(skb_put(skb, copy), copy, from) == copy)
return 0;
__skb_trim(skb, off);
return -EFAULT;
}
static inline bool skb_can_coalesce(struct sk_buff *skb, int i,
const struct page *page, int off)
{
if (i) {
const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
return page == skb_frag_page(frag) &&
off == frag->page_offset + skb_frag_size(frag);
}
return false;
}
static inline int __skb_linearize(struct sk_buff *skb)
{
return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
}
/**
* skb_linearize - convert paged skb to linear one
* @skb: buffer to linarize
*
* If there is no free memory -ENOMEM is returned, otherwise zero
* is returned and the old skb data released.
*/
static inline int skb_linearize(struct sk_buff *skb)
{
return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
}
/**
* skb_has_shared_frag - can any frag be overwritten
* @skb: buffer to test
*
* Return true if the skb has at least one frag that might be modified
* by an external entity (as in vmsplice()/sendfile())
*/
static inline bool skb_has_shared_frag(const struct sk_buff *skb)
{
return skb_is_nonlinear(skb) &&
skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
}
/**
* skb_linearize_cow - make sure skb is linear and writable
* @skb: buffer to process
*
* If there is no free memory -ENOMEM is returned, otherwise zero
* is returned and the old skb data released.
*/
static inline int skb_linearize_cow(struct sk_buff *skb)
{
return skb_is_nonlinear(skb) || skb_cloned(skb) ?
__skb_linearize(skb) : 0;
}
static __always_inline void
__skb_postpull_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
unsigned int off)
{
if (skb->ip_summed == CHECKSUM_COMPLETE)
skb->csum = csum_block_sub(skb->csum,
csum_partial(start, len, 0), off);
else if (skb->ip_summed == CHECKSUM_PARTIAL &&
skb_checksum_start_offset(skb) < 0)
skb->ip_summed = CHECKSUM_NONE;
}
/**
* skb_postpull_rcsum - update checksum for received skb after pull
* @skb: buffer to update
* @start: start of data before pull
* @len: length of data pulled
*
* After doing a pull on a received packet, you need to call this to
* update the CHECKSUM_COMPLETE checksum, or set ip_summed to
* CHECKSUM_NONE so that it can be recomputed from scratch.
*/
static inline void skb_postpull_rcsum(struct sk_buff *skb,
const void *start, unsigned int len)
{
__skb_postpull_rcsum(skb, start, len, 0);
}
static __always_inline void
__skb_postpush_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
unsigned int off)
{
if (skb->ip_summed == CHECKSUM_COMPLETE)
skb->csum = csum_block_add(skb->csum,
csum_partial(start, len, 0), off);
}
/**
* skb_postpush_rcsum - update checksum for received skb after push
* @skb: buffer to update
* @start: start of data after push
* @len: length of data pushed
*
* After doing a push on a received packet, you need to call this to
* update the CHECKSUM_COMPLETE checksum.
*/
static inline void skb_postpush_rcsum(struct sk_buff *skb,
const void *start, unsigned int len)
{
__skb_postpush_rcsum(skb, start, len, 0);
}
unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
/**
* skb_push_rcsum - push skb and update receive checksum
* @skb: buffer to update
* @len: length of data pulled
*
* This function performs an skb_push on the packet and updates
* the CHECKSUM_COMPLETE checksum. It should be used on
* receive path processing instead of skb_push unless you know
* that the checksum difference is zero (e.g., a valid IP header)
* or you are setting ip_summed to CHECKSUM_NONE.
*/
static inline unsigned char *skb_push_rcsum(struct sk_buff *skb,
unsigned int len)
{
skb_push(skb, len);
skb_postpush_rcsum(skb, skb->data, len);
return skb->data;
}
/**
* pskb_trim_rcsum - trim received skb and update checksum
* @skb: buffer to trim
* @len: new length
*
* This is exactly the same as pskb_trim except that it ensures the
* checksum of received packets are still valid after the operation.
*/
static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
{
if (likely(len >= skb->len))
return 0;
if (skb->ip_summed == CHECKSUM_COMPLETE)
skb->ip_summed = CHECKSUM_NONE;
return __pskb_trim(skb, len);
}
static inline int __skb_trim_rcsum(struct sk_buff *skb, unsigned int len)
{
if (skb->ip_summed == CHECKSUM_COMPLETE)
skb->ip_summed = CHECKSUM_NONE;
__skb_trim(skb, len);
return 0;
}
static inline int __skb_grow_rcsum(struct sk_buff *skb, unsigned int len)
{
if (skb->ip_summed == CHECKSUM_COMPLETE)
skb->ip_summed = CHECKSUM_NONE;
return __skb_grow(skb, len);
}
#define skb_queue_walk(queue, skb) \
for (skb = (queue)->next; \
skb != (struct sk_buff *)(queue); \
skb = skb->next)
#define skb_queue_walk_safe(queue, skb, tmp) \
for (skb = (queue)->next, tmp = skb->next; \
skb != (struct sk_buff *)(queue); \
skb = tmp, tmp = skb->next)
#define skb_queue_walk_from(queue, skb) \
for (; skb != (struct sk_buff *)(queue); \
skb = skb->next)
#define skb_queue_walk_from_safe(queue, skb, tmp) \
for (tmp = skb->next; \
skb != (struct sk_buff *)(queue); \
skb = tmp, tmp = skb->next)
#define skb_queue_reverse_walk(queue, skb) \
for (skb = (queue)->prev; \
skb != (struct sk_buff *)(queue); \
skb = skb->prev)
#define skb_queue_reverse_walk_safe(queue, skb, tmp) \
for (skb = (queue)->prev, tmp = skb->prev; \
skb != (struct sk_buff *)(queue); \
skb = tmp, tmp = skb->prev)
#define skb_queue_reverse_walk_from_safe(queue, skb, tmp) \
for (tmp = skb->prev; \
skb != (struct sk_buff *)(queue); \
skb = tmp, tmp = skb->prev)
static inline bool skb_has_frag_list(const struct sk_buff *skb)
{
return skb_shinfo(skb)->frag_list != NULL;
}
static inline void skb_frag_list_init(struct sk_buff *skb)
{
skb_shinfo(skb)->frag_list = NULL;
}
#define skb_walk_frags(skb, iter) \
for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
int __skb_wait_for_more_packets(struct sock *sk, int *err, long *timeo_p,
const struct sk_buff *skb);
struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned flags,
int *peeked, int *off, int *err,
struct sk_buff **last);
struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
int *peeked, int *off, int *err);
struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags, int noblock,
int *err);
unsigned int datagram_poll(struct file *file, struct socket *sock,
struct poll_table_struct *wait);
int skb_copy_datagram_iter(const struct sk_buff *from, int offset,
struct iov_iter *to, int size);
static inline int skb_copy_datagram_msg(const struct sk_buff *from, int offset,
struct msghdr *msg, int size)
{
return skb_copy_datagram_iter(from, offset, &msg->msg_iter, size);
}
int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen,
struct msghdr *msg);
int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
struct iov_iter *from, int len);
int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *frm);
void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
void __skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb, int len);
static inline void skb_free_datagram_locked(struct sock *sk,
struct sk_buff *skb)
{
__skb_free_datagram_locked(sk, skb, 0);
}
int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);
int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
int len, __wsum csum);
ssize_t skb_socket_splice(struct sock *sk,
struct pipe_inode_info *pipe,
struct splice_pipe_desc *spd);
int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
struct pipe_inode_info *pipe, unsigned int len,
unsigned int flags,
ssize_t (*splice_cb)(struct sock *,
struct pipe_inode_info *,
struct splice_pipe_desc *));
void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
int skb_zerocopy(struct sk_buff *to, struct sk_buff *from,
int len, int hlen);
void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len);
int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen);
void skb_scrub_packet(struct sk_buff *skb, bool xnet);
unsigned int skb_gso_transport_seglen(const struct sk_buff *skb);
bool skb_gso_validate_mtu(const struct sk_buff *skb, unsigned int mtu);
struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
struct sk_buff *skb_vlan_untag(struct sk_buff *skb);
int skb_ensure_writable(struct sk_buff *skb, int write_len);
int skb_vlan_pop(struct sk_buff *skb);
int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);
struct sk_buff *pskb_extract(struct sk_buff *skb, int off, int to_copy,
gfp_t gfp);
static inline int memcpy_from_msg(void *data, struct msghdr *msg, int len)
{
return copy_from_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
}
static inline int memcpy_to_msg(struct msghdr *msg, void *data, int len)
{
return copy_to_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
}
struct skb_checksum_ops {
__wsum (*update)(const void *mem, int len, __wsum wsum);
__wsum (*combine)(__wsum csum, __wsum csum2, int offset, int len);
};
__wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
__wsum csum, const struct skb_checksum_ops *ops);
__wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
__wsum csum);
static inline void * __must_check
__skb_header_pointer(const struct sk_buff *skb, int offset,
int len, void *data, int hlen, void *buffer)
{
if (hlen - offset >= len)
return data + offset;
if (!skb ||
skb_copy_bits(skb, offset, buffer, len) < 0)
return NULL;
return buffer;
}
static inline void * __must_check
skb_header_pointer(const struct sk_buff *skb, int offset, int len, void *buffer)
{
return __skb_header_pointer(skb, offset, len, skb->data,
skb_headlen(skb), buffer);
}
/**
* skb_needs_linearize - check if we need to linearize a given skb
* depending on the given device features.
* @skb: socket buffer to check
* @features: net device features
*
* Returns true if either:
* 1. skb has frag_list and the device doesn't support FRAGLIST, or
* 2. skb is fragmented and the device does not support SG.
*/
static inline bool skb_needs_linearize(struct sk_buff *skb,
netdev_features_t features)
{
return skb_is_nonlinear(skb) &&
((skb_has_frag_list(skb) && !(features & NETIF_F_FRAGLIST)) ||
(skb_shinfo(skb)->nr_frags && !(features & NETIF_F_SG)));
}
static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
void *to,
const unsigned int len)
{
memcpy(to, skb->data, len);
}
static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
const int offset, void *to,
const unsigned int len)
{
memcpy(to, skb->data + offset, len);
}
static inline void skb_copy_to_linear_data(struct sk_buff *skb,
const void *from,
const unsigned int len)
{
memcpy(skb->data, from, len);
}
static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
const int offset,
const void *from,
const unsigned int len)
{
memcpy(skb->data + offset, from, len);
}
void skb_init(void);
static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
{
return skb->tstamp;
}
/**
* skb_get_timestamp - get timestamp from a skb
* @skb: skb to get stamp from
* @stamp: pointer to struct timeval to store stamp in
*
* Timestamps are stored in the skb as offsets to a base timestamp.
* This function converts the offset back to a struct timeval and stores
* it in stamp.
*/
static inline void skb_get_timestamp(const struct sk_buff *skb,
struct timeval *stamp)
{
*stamp = ktime_to_timeval(skb->tstamp);
}
static inline void skb_get_timestampns(const struct sk_buff *skb,
struct timespec *stamp)
{
*stamp = ktime_to_timespec(skb->tstamp);
}
static inline void __net_timestamp(struct sk_buff *skb)
{
skb->tstamp = ktime_get_real();
}
static inline ktime_t net_timedelta(ktime_t t)
{
return ktime_sub(ktime_get_real(), t);
}
static inline ktime_t net_invalid_timestamp(void)
{
return ktime_set(0, 0);
}
struct sk_buff *skb_clone_sk(struct sk_buff *skb);
#ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
void skb_clone_tx_timestamp(struct sk_buff *skb);
bool skb_defer_rx_timestamp(struct sk_buff *skb);
#else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
{
}
static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
{
return false;
}
#endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
/**
* skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
*
* PHY drivers may accept clones of transmitted packets for
* timestamping via their phy_driver.txtstamp method. These drivers
* must call this function to return the skb back to the stack with a
* timestamp.
*
* @skb: clone of the the original outgoing packet
* @hwtstamps: hardware time stamps
*
*/
void skb_complete_tx_timestamp(struct sk_buff *skb,
struct skb_shared_hwtstamps *hwtstamps);
void __skb_tstamp_tx(struct sk_buff *orig_skb,
struct skb_shared_hwtstamps *hwtstamps,
struct sock *sk, int tstype);
/**
* skb_tstamp_tx - queue clone of skb with send time stamps
* @orig_skb: the original outgoing packet
* @hwtstamps: hardware time stamps, may be NULL if not available
*
* If the skb has a socket associated, then this function clones the
* skb (thus sharing the actual data and optional structures), stores
* the optional hardware time stamping information (if non NULL) or
* generates a software time stamp (otherwise), then queues the clone
* to the error queue of the socket. Errors are silently ignored.
*/
void skb_tstamp_tx(struct sk_buff *orig_skb,
struct skb_shared_hwtstamps *hwtstamps);
static inline void sw_tx_timestamp(struct sk_buff *skb)
{
if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
!(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
skb_tstamp_tx(skb, NULL);
}
/**
* skb_tx_timestamp() - Driver hook for transmit timestamping
*
* Ethernet MAC Drivers should call this function in their hard_xmit()
* function immediately before giving the sk_buff to the MAC hardware.
*
* Specifically, one should make absolutely sure that this function is
* called before TX completion of this packet can trigger. Otherwise
* the packet could potentially already be freed.
*
* @skb: A socket buffer.
*/
static inline void skb_tx_timestamp(struct sk_buff *skb)
{
skb_clone_tx_timestamp(skb);
sw_tx_timestamp(skb);
}
/**
* skb_complete_wifi_ack - deliver skb with wifi status
*
* @skb: the original outgoing packet
* @acked: ack status
*
*/
void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
__sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
__sum16 __skb_checksum_complete(struct sk_buff *skb);
static inline int skb_csum_unnecessary(const struct sk_buff *skb)
{
return ((skb->ip_summed == CHECKSUM_UNNECESSARY) ||
skb->csum_valid ||
(skb->ip_summed == CHECKSUM_PARTIAL &&
skb_checksum_start_offset(skb) >= 0));
}
/**
* skb_checksum_complete - Calculate checksum of an entire packet
* @skb: packet to process
*
* This function calculates the checksum over the entire packet plus
* the value of skb->csum. The latter can be used to supply the
* checksum of a pseudo header as used by TCP/UDP. It returns the
* checksum.
*
* For protocols that contain complete checksums such as ICMP/TCP/UDP,
* this function can be used to verify that checksum on received
* packets. In that case the function should return zero if the
* checksum is correct. In particular, this function will return zero
* if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
* hardware has already verified the correctness of the checksum.
*/
static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
{
return skb_csum_unnecessary(skb) ?
0 : __skb_checksum_complete(skb);
}
static inline void __skb_decr_checksum_unnecessary(struct sk_buff *skb)
{
if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
if (skb->csum_level == 0)
skb->ip_summed = CHECKSUM_NONE;
else
skb->csum_level--;
}
}
static inline void __skb_incr_checksum_unnecessary(struct sk_buff *skb)
{
if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
skb->csum_level++;
} else if (skb->ip_summed == CHECKSUM_NONE) {
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb->csum_level = 0;
}
}
static inline void __skb_mark_checksum_bad(struct sk_buff *skb)
{
/* Mark current checksum as bad (typically called from GRO
* path). In the case that ip_summed is CHECKSUM_NONE
* this must be the first checksum encountered in the packet.
* When ip_summed is CHECKSUM_UNNECESSARY, this is the first
* checksum after the last one validated. For UDP, a zero
* checksum can not be marked as bad.
*/
if (skb->ip_summed == CHECKSUM_NONE ||
skb->ip_summed == CHECKSUM_UNNECESSARY)
skb->csum_bad = 1;
}
/* Check if we need to perform checksum complete validation.
*
* Returns true if checksum complete is needed, false otherwise
* (either checksum is unnecessary or zero checksum is allowed).
*/
static inline bool __skb_checksum_validate_needed(struct sk_buff *skb,
bool zero_okay,
__sum16 check)
{
if (skb_csum_unnecessary(skb) || (zero_okay && !check)) {
skb->csum_valid = 1;
__skb_decr_checksum_unnecessary(skb);
return false;
}
return true;
}
/* For small packets <= CHECKSUM_BREAK peform checksum complete directly
* in checksum_init.
*/
#define CHECKSUM_BREAK 76
/* Unset checksum-complete
*
* Unset checksum complete can be done when packet is being modified
* (uncompressed for instance) and checksum-complete value is
* invalidated.
*/
static inline void skb_checksum_complete_unset(struct sk_buff *skb)
{
if (skb->ip_summed == CHECKSUM_COMPLETE)
skb->ip_summed = CHECKSUM_NONE;
}
/* Validate (init) checksum based on checksum complete.
*
* Return values:
* 0: checksum is validated or try to in skb_checksum_complete. In the latter
* case the ip_summed will not be CHECKSUM_UNNECESSARY and the pseudo
* checksum is stored in skb->csum for use in __skb_checksum_complete
* non-zero: value of invalid checksum
*
*/
static inline __sum16 __skb_checksum_validate_complete(struct sk_buff *skb,
bool complete,
__wsum psum)
{
if (skb->ip_summed == CHECKSUM_COMPLETE) {
if (!csum_fold(csum_add(psum, skb->csum))) {
skb->csum_valid = 1;
return 0;
}
} else if (skb->csum_bad) {
/* ip_summed == CHECKSUM_NONE in this case */
return (__force __sum16)1;
}
skb->csum = psum;
if (complete || skb->len <= CHECKSUM_BREAK) {
__sum16 csum;
csum = __skb_checksum_complete(skb);
skb->csum_valid = !csum;
return csum;
}
return 0;
}
static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto)
{
return 0;
}
/* Perform checksum validate (init). Note that this is a macro since we only
* want to calculate the pseudo header which is an input function if necessary.
* First we try to validate without any computation (checksum unnecessary) and
* then calculate based on checksum complete calling the function to compute
* pseudo header.
*
* Return values:
* 0: checksum is validated or try to in skb_checksum_complete
* non-zero: value of invalid checksum
*/
#define __skb_checksum_validate(skb, proto, complete, \
zero_okay, check, compute_pseudo) \
({ \
__sum16 __ret = 0; \
skb->csum_valid = 0; \
if (__skb_checksum_validate_needed(skb, zero_okay, check)) \
__ret = __skb_checksum_validate_complete(skb, \
complete, compute_pseudo(skb, proto)); \
__ret; \
})
#define skb_checksum_init(skb, proto, compute_pseudo) \
__skb_checksum_validate(skb, proto, false, false, 0, compute_pseudo)
#define skb_checksum_init_zero_check(skb, proto, check, compute_pseudo) \
__skb_checksum_validate(skb, proto, false, true, check, compute_pseudo)
#define skb_checksum_validate(skb, proto, compute_pseudo) \
__skb_checksum_validate(skb, proto, true, false, 0, compute_pseudo)
#define skb_checksum_validate_zero_check(skb, proto, check, \
compute_pseudo) \
__skb_checksum_validate(skb, proto, true, true, check, compute_pseudo)
#define skb_checksum_simple_validate(skb) \
__skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo)
static inline bool __skb_checksum_convert_check(struct sk_buff *skb)
{
return (skb->ip_summed == CHECKSUM_NONE &&
skb->csum_valid && !skb->csum_bad);
}
static inline void __skb_checksum_convert(struct sk_buff *skb,
__sum16 check, __wsum pseudo)
{
skb->csum = ~pseudo;
skb->ip_summed = CHECKSUM_COMPLETE;
}
#define skb_checksum_try_convert(skb, proto, check, compute_pseudo) \
do { \
if (__skb_checksum_convert_check(skb)) \
__skb_checksum_convert(skb, check, \
compute_pseudo(skb, proto)); \
} while (0)
static inline void skb_remcsum_adjust_partial(struct sk_buff *skb, void *ptr,
u16 start, u16 offset)
{
skb->ip_summed = CHECKSUM_PARTIAL;
skb->csum_start = ((unsigned char *)ptr + start) - skb->head;
skb->csum_offset = offset - start;
}
/* Update skbuf and packet to reflect the remote checksum offload operation.
* When called, ptr indicates the starting point for skb->csum when
* ip_summed is CHECKSUM_COMPLETE. If we need create checksum complete
* here, skb_postpull_rcsum is done so skb->csum start is ptr.
*/
static inline void skb_remcsum_process(struct sk_buff *skb, void *ptr,
int start, int offset, bool nopartial)
{
__wsum delta;
if (!nopartial) {
skb_remcsum_adjust_partial(skb, ptr, start, offset);
return;
}
if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE)) {
__skb_checksum_complete(skb);
skb_postpull_rcsum(skb, skb->data, ptr - (void *)skb->data);
}
delta = remcsum_adjust(ptr, skb->csum, start, offset);
/* Adjust skb->csum since we changed the packet */
skb->csum = csum_add(skb->csum, delta);
}
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
void nf_conntrack_destroy(struct nf_conntrack *nfct);
static inline void nf_conntrack_put(struct nf_conntrack *nfct)
{
if (nfct && atomic_dec_and_test(&nfct->use))
nf_conntrack_destroy(nfct);
}
static inline void nf_conntrack_get(struct nf_conntrack *nfct)
{
if (nfct)
atomic_inc(&nfct->use);
}
#endif
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
{
if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
kfree(nf_bridge);
}
static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
{
if (nf_bridge)
atomic_inc(&nf_bridge->use);
}
#endif /* CONFIG_BRIDGE_NETFILTER */
static inline void nf_reset(struct sk_buff *skb)
{
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
nf_conntrack_put(skb->nfct);
skb->nfct = NULL;
#endif
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
nf_bridge_put(skb->nf_bridge);
skb->nf_bridge = NULL;
#endif
}
static inline void nf_reset_trace(struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
skb->nf_trace = 0;
#endif
}
/* Note: This doesn't put any conntrack and bridge info in dst. */
static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src,
bool copy)
{
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
dst->nfct = src->nfct;
nf_conntrack_get(src->nfct);
if (copy)
dst->nfctinfo = src->nfctinfo;
#endif
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
dst->nf_bridge = src->nf_bridge;
nf_bridge_get(src->nf_bridge);
#endif
#if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
if (copy)
dst->nf_trace = src->nf_trace;
#endif
}
static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
{
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
nf_conntrack_put(dst->nfct);
#endif
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
nf_bridge_put(dst->nf_bridge);
#endif
__nf_copy(dst, src, true);
}
#ifdef CONFIG_NETWORK_SECMARK
static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
{
to->secmark = from->secmark;
}
static inline void skb_init_secmark(struct sk_buff *skb)
{
skb->secmark = 0;
}
#else
static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
{ }
static inline void skb_init_secmark(struct sk_buff *skb)
{ }
#endif
static inline bool skb_irq_freeable(const struct sk_buff *skb)
{
return !skb->destructor &&
#if IS_ENABLED(CONFIG_XFRM)
!skb->sp &&
#endif
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
!skb->nfct &&
#endif
!skb->_skb_refdst &&
!skb_has_frag_list(skb);
}
static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
{
skb->queue_mapping = queue_mapping;
}
static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
{
return skb->queue_mapping;
}
static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
{
to->queue_mapping = from->queue_mapping;
}
static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
{
skb->queue_mapping = rx_queue + 1;
}
static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
{
return skb->queue_mapping - 1;
}
static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
{
return skb->queue_mapping != 0;
}
static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
{
#ifdef CONFIG_XFRM
return skb->sp;
#else
return NULL;
#endif
}
/* Keeps track of mac header offset relative to skb->head.
* It is useful for TSO of Tunneling protocol. e.g. GRE.
* For non-tunnel skb it points to skb_mac_header() and for
* tunnel skb it points to outer mac header.
* Keeps track of level of encapsulation of network headers.
*/
struct skb_gso_cb {
union {
int mac_offset;
int data_offset;
};
int encap_level;
__wsum csum;
__u16 csum_start;
};
#define SKB_SGO_CB_OFFSET 32
#define SKB_GSO_CB(skb) ((struct skb_gso_cb *)((skb)->cb + SKB_SGO_CB_OFFSET))
static inline int skb_tnl_header_len(const struct sk_buff *inner_skb)
{
return (skb_mac_header(inner_skb) - inner_skb->head) -
SKB_GSO_CB(inner_skb)->mac_offset;
}
static inline int gso_pskb_expand_head(struct sk_buff *skb, int extra)
{
int new_headroom, headroom;
int ret;
headroom = skb_headroom(skb);
ret = pskb_expand_head(skb, extra, 0, GFP_ATOMIC);
if (ret)
return ret;
new_headroom = skb_headroom(skb);
SKB_GSO_CB(skb)->mac_offset += (new_headroom - headroom);
return 0;
}
static inline void gso_reset_checksum(struct sk_buff *skb, __wsum res)
{
/* Do not update partial checksums if remote checksum is enabled. */
if (skb->remcsum_offload)
return;
SKB_GSO_CB(skb)->csum = res;
SKB_GSO_CB(skb)->csum_start = skb_checksum_start(skb) - skb->head;
}
/* Compute the checksum for a gso segment. First compute the checksum value
* from the start of transport header to SKB_GSO_CB(skb)->csum_start, and
* then add in skb->csum (checksum from csum_start to end of packet).
* skb->csum and csum_start are then updated to reflect the checksum of the
* resultant packet starting from the transport header-- the resultant checksum
* is in the res argument (i.e. normally zero or ~ of checksum of a pseudo
* header.
*/
static inline __sum16 gso_make_checksum(struct sk_buff *skb, __wsum res)
{
unsigned char *csum_start = skb_transport_header(skb);
int plen = (skb->head + SKB_GSO_CB(skb)->csum_start) - csum_start;
__wsum partial = SKB_GSO_CB(skb)->csum;
SKB_GSO_CB(skb)->csum = res;
SKB_GSO_CB(skb)->csum_start = csum_start - skb->head;
return csum_fold(csum_partial(csum_start, plen, partial));
}
static inline bool skb_is_gso(const struct sk_buff *skb)
{
return skb_shinfo(skb)->gso_size;
}
/* Note: Should be called only if skb_is_gso(skb) is true */
static inline bool skb_is_gso_v6(const struct sk_buff *skb)
{
return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
}
static inline void skb_gso_reset(struct sk_buff *skb)
{
skb_shinfo(skb)->gso_size = 0;
skb_shinfo(skb)->gso_segs = 0;
skb_shinfo(skb)->gso_type = 0;
}
void __skb_warn_lro_forwarding(const struct sk_buff *skb);
static inline bool skb_warn_if_lro(const struct sk_buff *skb)
{
/* LRO sets gso_size but not gso_type, whereas if GSO is really
* wanted then gso_type will be set. */
const struct skb_shared_info *shinfo = skb_shinfo(skb);
if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
unlikely(shinfo->gso_type == 0)) {
__skb_warn_lro_forwarding(skb);
return true;
}
return false;
}
static inline void skb_forward_csum(struct sk_buff *skb)
{
/* Unfortunately we don't support this one. Any brave souls? */
if (skb->ip_summed == CHECKSUM_COMPLETE)
skb->ip_summed = CHECKSUM_NONE;
}
/**
* skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
* @skb: skb to check
*
* fresh skbs have their ip_summed set to CHECKSUM_NONE.
* Instead of forcing ip_summed to CHECKSUM_NONE, we can
* use this helper, to document places where we make this assertion.
*/
static inline void skb_checksum_none_assert(const struct sk_buff *skb)
{
#ifdef DEBUG
BUG_ON(skb->ip_summed != CHECKSUM_NONE);
#endif
}
bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
int skb_checksum_setup(struct sk_buff *skb, bool recalculate);
struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
unsigned int transport_len,
__sum16(*skb_chkf)(struct sk_buff *skb));
/**
* skb_head_is_locked - Determine if the skb->head is locked down
* @skb: skb to check
*
* The head on skbs build around a head frag can be removed if they are
* not cloned. This function returns true if the skb head is locked down
* due to either being allocated via kmalloc, or by being a clone with
* multiple references to the head.
*/
static inline bool skb_head_is_locked(const struct sk_buff *skb)
{
return !skb->head_frag || skb_cloned(skb);
}
/**
* skb_gso_network_seglen - Return length of individual segments of a gso packet
*
* @skb: GSO skb
*
* skb_gso_network_seglen is used to determine the real size of the
* individual segments, including Layer3 (IP, IPv6) and L4 headers (TCP/UDP).
*
* The MAC/L2 header is not accounted for.
*/
static inline unsigned int skb_gso_network_seglen(const struct sk_buff *skb)
{
unsigned int hdr_len = skb_transport_header(skb) -
skb_network_header(skb);
return hdr_len + skb_gso_transport_seglen(skb);
}
/* Local Checksum Offload.
* Compute outer checksum based on the assumption that the
* inner checksum will be offloaded later.
* See Documentation/networking/checksum-offloads.txt for
* explanation of how this works.
* Fill in outer checksum adjustment (e.g. with sum of outer
* pseudo-header) before calling.
* Also ensure that inner checksum is in linear data area.
*/
static inline __wsum lco_csum(struct sk_buff *skb)
{
unsigned char *csum_start = skb_checksum_start(skb);
unsigned char *l4_hdr = skb_transport_header(skb);
__wsum partial;
/* Start with complement of inner checksum adjustment */
partial = ~csum_unfold(*(__force __sum16 *)(csum_start +
skb->csum_offset));
/* Add in checksum of our headers (incl. outer checksum
* adjustment filled in by caller) and return result.
*/
return csum_partial(l4_hdr, csum_start - l4_hdr, partial);
}
#endif /* __KERNEL__ */
#endif /* _LINUX_SKBUFF_H */
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