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52e01b84a2
linux_dsm_epyc7002/net/openvswitch/conntrack.c
David S. Miller 52e01b84a2 Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next 
Pablo Neira Ayuso says:

====================
Netfilter updates for net-next

The following patchset contains Netfilter updates for your net-next
tree, they are:

1) Stash ctinfo 3-bit field into pointer to nf_conntrack object from
   sk_buff so we only access one single cacheline in the conntrack
   hotpath. Patchset from Florian Westphal.

2) Don't leak pointer to internal structures when exporting x_tables
   ruleset back to userspace, from Willem DeBruijn. This includes new
   helper functions to copy data to userspace such as xt_data_to_user()
   as well as conversions of our ip_tables, ip6_tables and arp_tables
   clients to use it. Not surprinsingly, ebtables requires an ad-hoc
   update. There is also a new field in x_tables extensions to indicate
   the amount of bytes that we copy to userspace.

3) Add nf_log_all_netns sysctl: This new knob allows you to enable
   logging via nf_log infrastructure for all existing netnamespaces.
   Given the effort to provide pernet syslog has been discontinued,
   let's provide a way to restore logging using netfilter kernel logging
   facilities in trusted environments. Patch from Michal Kubecek.

4) Validate SCTP checksum from conntrack helper, from Davide Caratti.

5) Merge UDPlite conntrack and NAT helpers into UDP, this was mostly
   a copy&paste from the original helper, from Florian Westphal.

6) Reset netfilter state when duplicating packets, also from Florian.

7) Remove unnecessary check for broadcast in IPv6 in pkttype match and
   nft_meta, from Liping Zhang.

8) Add missing code to deal with loopback packets from nft_meta when
   used by the netdev family, also from Liping.

9) Several cleanups on nf_tables, one to remove unnecessary check from
   the netlink control plane path to add table, set and stateful objects
   and code consolidation when unregister chain hooks, from Gao Feng.

10) Fix harmless reference counter underflow in IPVS that, however,
    results in problems with the introduction of the new refcount_t
    type, from David Windsor.

11) Enable LIBCRC32C from nf_ct_sctp instead of nf_nat_sctp,
    from Davide Caratti.

12) Missing documentation on nf_tables uapi header, from Liping Zhang.

13) Use rb_entry() helper in xt_connlimit, from Geliang Tang.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-03 16:58:20 -05:00

1392 lines
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/*
* Copyright (c) 2015 Nicira, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <linux/module.h>
#include <linux/openvswitch.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/sctp.h>
#include <net/ip.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_labels.h>
#include <net/netfilter/nf_conntrack_seqadj.h>
#include <net/netfilter/nf_conntrack_zones.h>
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
#ifdef CONFIG_NF_NAT_NEEDED
#include <linux/netfilter/nf_nat.h>
#include <net/netfilter/nf_nat_core.h>
#include <net/netfilter/nf_nat_l3proto.h>
#endif
#include "datapath.h"
#include "conntrack.h"
#include "flow.h"
#include "flow_netlink.h"
struct ovs_ct_len_tbl {
int maxlen;
int minlen;
};
/* Metadata mark for masked write to conntrack mark */
struct md_mark {
u32 value;
u32 mask;
};
/* Metadata label for masked write to conntrack label. */
struct md_labels {
struct ovs_key_ct_labels value;
struct ovs_key_ct_labels mask;
};
enum ovs_ct_nat {
OVS_CT_NAT = 1 << 0, /* NAT for committed connections only. */
OVS_CT_SRC_NAT = 1 << 1, /* Source NAT for NEW connections. */
OVS_CT_DST_NAT = 1 << 2, /* Destination NAT for NEW connections. */
};
/* Conntrack action context for execution. */
struct ovs_conntrack_info {
struct nf_conntrack_helper *helper;
struct nf_conntrack_zone zone;
struct nf_conn *ct;
u8 commit : 1;
u8 nat : 3; /* enum ovs_ct_nat */
u16 family;
struct md_mark mark;
struct md_labels labels;
#ifdef CONFIG_NF_NAT_NEEDED
struct nf_nat_range range; /* Only present for SRC NAT and DST NAT. */
#endif
};
static void __ovs_ct_free_action(struct ovs_conntrack_info *ct_info);
static u16 key_to_nfproto(const struct sw_flow_key *key)
{
switch (ntohs(key->eth.type)) {
case ETH_P_IP:
return NFPROTO_IPV4;
case ETH_P_IPV6:
return NFPROTO_IPV6;
default:
return NFPROTO_UNSPEC;
}
}
/* Map SKB connection state into the values used by flow definition. */
static u8 ovs_ct_get_state(enum ip_conntrack_info ctinfo)
{
u8 ct_state = OVS_CS_F_TRACKED;
switch (ctinfo) {
case IP_CT_ESTABLISHED_REPLY:
case IP_CT_RELATED_REPLY:
ct_state |= OVS_CS_F_REPLY_DIR;
break;
default:
break;
}
switch (ctinfo) {
case IP_CT_ESTABLISHED:
case IP_CT_ESTABLISHED_REPLY:
ct_state |= OVS_CS_F_ESTABLISHED;
break;
case IP_CT_RELATED:
case IP_CT_RELATED_REPLY:
ct_state |= OVS_CS_F_RELATED;
break;
case IP_CT_NEW:
ct_state |= OVS_CS_F_NEW;
break;
default:
break;
}
return ct_state;
}
static u32 ovs_ct_get_mark(const struct nf_conn *ct)
{
#if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)
return ct ? ct->mark : 0;
#else
return 0;
#endif
}
static void ovs_ct_get_labels(const struct nf_conn *ct,
struct ovs_key_ct_labels *labels)
{
struct nf_conn_labels *cl = ct ? nf_ct_labels_find(ct) : NULL;
if (cl) {
size_t len = sizeof(cl->bits);
if (len > OVS_CT_LABELS_LEN)
len = OVS_CT_LABELS_LEN;
else if (len < OVS_CT_LABELS_LEN)
memset(labels, 0, OVS_CT_LABELS_LEN);
memcpy(labels, cl->bits, len);
} else {
memset(labels, 0, OVS_CT_LABELS_LEN);
}
}
static void __ovs_ct_update_key(struct sw_flow_key *key, u8 state,
const struct nf_conntrack_zone *zone,
const struct nf_conn *ct)
{
key->ct.state = state;
key->ct.zone = zone->id;
key->ct.mark = ovs_ct_get_mark(ct);
ovs_ct_get_labels(ct, &key->ct.labels);
}
/* Update 'key' based on skb->nfct. If 'post_ct' is true, then OVS has
* previously sent the packet to conntrack via the ct action. If
* 'keep_nat_flags' is true, the existing NAT flags retained, else they are
* initialized from the connection status.
*/
static void ovs_ct_update_key(const struct sk_buff *skb,
const struct ovs_conntrack_info *info,
struct sw_flow_key *key, bool post_ct,
bool keep_nat_flags)
{
const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt;
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
u8 state = 0;
ct = nf_ct_get(skb, &ctinfo);
if (ct) {
state = ovs_ct_get_state(ctinfo);
/* All unconfirmed entries are NEW connections. */
if (!nf_ct_is_confirmed(ct))
state |= OVS_CS_F_NEW;
/* OVS persists the related flag for the duration of the
* connection.
*/
if (ct->master)
state |= OVS_CS_F_RELATED;
if (keep_nat_flags) {
state |= key->ct.state & OVS_CS_F_NAT_MASK;
} else {
if (ct->status & IPS_SRC_NAT)
state |= OVS_CS_F_SRC_NAT;
if (ct->status & IPS_DST_NAT)
state |= OVS_CS_F_DST_NAT;
}
zone = nf_ct_zone(ct);
} else if (post_ct) {
state = OVS_CS_F_TRACKED | OVS_CS_F_INVALID;
if (info)
zone = &info->zone;
}
__ovs_ct_update_key(key, state, zone, ct);
}
/* This is called to initialize CT key fields possibly coming in from the local
* stack.
*/
void ovs_ct_fill_key(const struct sk_buff *skb, struct sw_flow_key *key)
{
ovs_ct_update_key(skb, NULL, key, false, false);
}
int ovs_ct_put_key(const struct sw_flow_key *key, struct sk_buff *skb)
{
if (nla_put_u32(skb, OVS_KEY_ATTR_CT_STATE, key->ct.state))
return -EMSGSIZE;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
nla_put_u16(skb, OVS_KEY_ATTR_CT_ZONE, key->ct.zone))
return -EMSGSIZE;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) &&
nla_put_u32(skb, OVS_KEY_ATTR_CT_MARK, key->ct.mark))
return -EMSGSIZE;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
nla_put(skb, OVS_KEY_ATTR_CT_LABELS, sizeof(key->ct.labels),
&key->ct.labels))
return -EMSGSIZE;
return 0;
}
static int ovs_ct_set_mark(struct sk_buff *skb, struct sw_flow_key *key,
u32 ct_mark, u32 mask)
{
#if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
u32 new_mark;
/* The connection could be invalid, in which case set_mark is no-op. */
ct = nf_ct_get(skb, &ctinfo);
if (!ct)
return 0;
new_mark = ct_mark | (ct->mark & ~(mask));
if (ct->mark != new_mark) {
ct->mark = new_mark;
nf_conntrack_event_cache(IPCT_MARK, ct);
key->ct.mark = new_mark;
}
return 0;
#else
return -ENOTSUPP;
#endif
}
static int ovs_ct_set_labels(struct sk_buff *skb, struct sw_flow_key *key,
const struct ovs_key_ct_labels *labels,
const struct ovs_key_ct_labels *mask)
{
enum ip_conntrack_info ctinfo;
struct nf_conn_labels *cl;
struct nf_conn *ct;
int err;
/* The connection could be invalid, in which case set_label is no-op.*/
ct = nf_ct_get(skb, &ctinfo);
if (!ct)
return 0;
cl = nf_ct_labels_find(ct);
if (!cl) {
nf_ct_labels_ext_add(ct);
cl = nf_ct_labels_find(ct);
}
if (!cl || sizeof(cl->bits) < OVS_CT_LABELS_LEN)
return -ENOSPC;
err = nf_connlabels_replace(ct, (u32 *)labels, (u32 *)mask,
OVS_CT_LABELS_LEN / sizeof(u32));
if (err)
return err;
ovs_ct_get_labels(ct, &key->ct.labels);
return 0;
}
/* 'skb' should already be pulled to nh_ofs. */
static int ovs_ct_helper(struct sk_buff *skb, u16 proto)
{
const struct nf_conntrack_helper *helper;
const struct nf_conn_help *help;
enum ip_conntrack_info ctinfo;
unsigned int protoff;
struct nf_conn *ct;
int err;
ct = nf_ct_get(skb, &ctinfo);
if (!ct || ctinfo == IP_CT_RELATED_REPLY)
return NF_ACCEPT;
help = nfct_help(ct);
if (!help)
return NF_ACCEPT;
helper = rcu_dereference(help->helper);
if (!helper)
return NF_ACCEPT;
switch (proto) {
case NFPROTO_IPV4:
protoff = ip_hdrlen(skb);
break;
case NFPROTO_IPV6: {
u8 nexthdr = ipv6_hdr(skb)->nexthdr;
__be16 frag_off;
int ofs;
ofs = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr,
&frag_off);
if (ofs < 0 || (frag_off & htons(~0x7)) != 0) {
pr_debug("proto header not found\n");
return NF_ACCEPT;
}
protoff = ofs;
break;
}
default:
WARN_ONCE(1, "helper invoked on non-IP family!");
return NF_DROP;
}
err = helper->help(skb, protoff, ct, ctinfo);
if (err != NF_ACCEPT)
return err;
/* Adjust seqs after helper. This is needed due to some helpers (e.g.,
* FTP with NAT) adusting the TCP payload size when mangling IP
* addresses and/or port numbers in the text-based control connection.
*/
if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
!nf_ct_seq_adjust(skb, ct, ctinfo, protoff))
return NF_DROP;
return NF_ACCEPT;
}
/* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero
* value if 'skb' is freed.
*/
static int handle_fragments(struct net *net, struct sw_flow_key *key,
u16 zone, struct sk_buff *skb)
{
struct ovs_skb_cb ovs_cb = *OVS_CB(skb);
int err;
if (key->eth.type == htons(ETH_P_IP)) {
enum ip_defrag_users user = IP_DEFRAG_CONNTRACK_IN + zone;
memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
err = ip_defrag(net, skb, user);
if (err)
return err;
ovs_cb.mru = IPCB(skb)->frag_max_size;
#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
} else if (key->eth.type == htons(ETH_P_IPV6)) {
enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone;
skb_orphan(skb);
memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
err = nf_ct_frag6_gather(net, skb, user);
if (err) {
if (err != -EINPROGRESS)
kfree_skb(skb);
return err;
}
key->ip.proto = ipv6_hdr(skb)->nexthdr;
ovs_cb.mru = IP6CB(skb)->frag_max_size;
#endif
} else {
kfree_skb(skb);
return -EPFNOSUPPORT;
}
key->ip.frag = OVS_FRAG_TYPE_NONE;
skb_clear_hash(skb);
skb->ignore_df = 1;
*OVS_CB(skb) = ovs_cb;
return 0;
}
static struct nf_conntrack_expect *
ovs_ct_expect_find(struct net *net, const struct nf_conntrack_zone *zone,
u16 proto, const struct sk_buff *skb)
{
struct nf_conntrack_tuple tuple;
if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), proto, net, &tuple))
return NULL;
return __nf_ct_expect_find(net, zone, &tuple);
}
/* This replicates logic from nf_conntrack_core.c that is not exported. */
static enum ip_conntrack_info
ovs_ct_get_info(const struct nf_conntrack_tuple_hash *h)
{
const struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
return IP_CT_ESTABLISHED_REPLY;
/* Once we've had two way comms, always ESTABLISHED. */
if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status))
return IP_CT_ESTABLISHED;
if (test_bit(IPS_EXPECTED_BIT, &ct->status))
return IP_CT_RELATED;
return IP_CT_NEW;
}
/* Find an existing connection which this packet belongs to without
* re-attributing statistics or modifying the connection state. This allows an
* skb->nfct lost due to an upcall to be recovered during actions execution.
*
* Must be called with rcu_read_lock.
*
* On success, populates skb->nfct and skb->nfctinfo, and returns the
* connection. Returns NULL if there is no existing entry.
*/
static struct nf_conn *
ovs_ct_find_existing(struct net *net, const struct nf_conntrack_zone *zone,
u8 l3num, struct sk_buff *skb)
{
struct nf_conntrack_l3proto *l3proto;
struct nf_conntrack_l4proto *l4proto;
struct nf_conntrack_tuple tuple;
struct nf_conntrack_tuple_hash *h;
struct nf_conn *ct;
unsigned int dataoff;
u8 protonum;
l3proto = __nf_ct_l3proto_find(l3num);
if (l3proto->get_l4proto(skb, skb_network_offset(skb), &dataoff,
&protonum) <= 0) {
pr_debug("ovs_ct_find_existing: Can't get protonum\n");
return NULL;
}
l4proto = __nf_ct_l4proto_find(l3num, protonum);
if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num,
protonum, net, &tuple, l3proto, l4proto)) {
pr_debug("ovs_ct_find_existing: Can't get tuple\n");
return NULL;
}
/* look for tuple match */
h = nf_conntrack_find_get(net, zone, &tuple);
if (!h)
return NULL; /* Not found. */
ct = nf_ct_tuplehash_to_ctrack(h);
nf_ct_set(skb, ct, ovs_ct_get_info(h));
return ct;
}
/* Determine whether skb->nfct is equal to the result of conntrack lookup. */
static bool skb_nfct_cached(struct net *net,
const struct sw_flow_key *key,
const struct ovs_conntrack_info *info,
struct sk_buff *skb)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
ct = nf_ct_get(skb, &ctinfo);
/* If no ct, check if we have evidence that an existing conntrack entry
* might be found for this skb. This happens when we lose a skb->nfct
* due to an upcall. If the connection was not confirmed, it is not
* cached and needs to be run through conntrack again.
*/
if (!ct && key->ct.state & OVS_CS_F_TRACKED &&
!(key->ct.state & OVS_CS_F_INVALID) &&
key->ct.zone == info->zone.id)
ct = ovs_ct_find_existing(net, &info->zone, info->family, skb);
if (!ct)
return false;
if (!net_eq(net, read_pnet(&ct->ct_net)))
return false;
if (!nf_ct_zone_equal_any(info->ct, nf_ct_zone(ct)))
return false;
if (info->helper) {
struct nf_conn_help *help;
help = nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
if (help && rcu_access_pointer(help->helper) != info->helper)
return false;
}
return true;
}
#ifdef CONFIG_NF_NAT_NEEDED
/* Modelled after nf_nat_ipv[46]_fn().
* range is only used for new, uninitialized NAT state.
* Returns either NF_ACCEPT or NF_DROP.
*/
static int ovs_ct_nat_execute(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
const struct nf_nat_range *range,
enum nf_nat_manip_type maniptype)
{
int hooknum, nh_off, err = NF_ACCEPT;
nh_off = skb_network_offset(skb);
skb_pull_rcsum(skb, nh_off);
/* See HOOK2MANIP(). */
if (maniptype == NF_NAT_MANIP_SRC)
hooknum = NF_INET_LOCAL_IN; /* Source NAT */
else
hooknum = NF_INET_LOCAL_OUT; /* Destination NAT */
switch (ctinfo) {
case IP_CT_RELATED:
case IP_CT_RELATED_REPLY:
if (IS_ENABLED(CONFIG_NF_NAT_IPV4) &&
skb->protocol == htons(ETH_P_IP) &&
ip_hdr(skb)->protocol == IPPROTO_ICMP) {
if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo,
hooknum))
err = NF_DROP;
goto push;
} else if (IS_ENABLED(CONFIG_NF_NAT_IPV6) &&
skb->protocol == htons(ETH_P_IPV6)) {
__be16 frag_off;
u8 nexthdr = ipv6_hdr(skb)->nexthdr;
int hdrlen = ipv6_skip_exthdr(skb,
sizeof(struct ipv6hdr),
&nexthdr, &frag_off);
if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) {
if (!nf_nat_icmpv6_reply_translation(skb, ct,
ctinfo,
hooknum,
hdrlen))
err = NF_DROP;
goto push;
}
}
/* Non-ICMP, fall thru to initialize if needed. */
case IP_CT_NEW:
/* Seen it before? This can happen for loopback, retrans,
* or local packets.
*/
if (!nf_nat_initialized(ct, maniptype)) {
/* Initialize according to the NAT action. */
err = (range && range->flags & NF_NAT_RANGE_MAP_IPS)
/* Action is set up to establish a new
* mapping.
*/
? nf_nat_setup_info(ct, range, maniptype)
: nf_nat_alloc_null_binding(ct, hooknum);
if (err != NF_ACCEPT)
goto push;
}
break;
case IP_CT_ESTABLISHED:
case IP_CT_ESTABLISHED_REPLY:
break;
default:
err = NF_DROP;
goto push;
}
err = nf_nat_packet(ct, ctinfo, hooknum, skb);
push:
skb_push(skb, nh_off);
skb_postpush_rcsum(skb, skb->data, nh_off);
return err;
}
static void ovs_nat_update_key(struct sw_flow_key *key,
const struct sk_buff *skb,
enum nf_nat_manip_type maniptype)
{
if (maniptype == NF_NAT_MANIP_SRC) {
__be16 src;
key->ct.state |= OVS_CS_F_SRC_NAT;
if (key->eth.type == htons(ETH_P_IP))
key->ipv4.addr.src = ip_hdr(skb)->saddr;
else if (key->eth.type == htons(ETH_P_IPV6))
memcpy(&key->ipv6.addr.src, &ipv6_hdr(skb)->saddr,
sizeof(key->ipv6.addr.src));
else
return;
if (key->ip.proto == IPPROTO_UDP)
src = udp_hdr(skb)->source;
else if (key->ip.proto == IPPROTO_TCP)
src = tcp_hdr(skb)->source;
else if (key->ip.proto == IPPROTO_SCTP)
src = sctp_hdr(skb)->source;
else
return;
key->tp.src = src;
} else {
__be16 dst;
key->ct.state |= OVS_CS_F_DST_NAT;
if (key->eth.type == htons(ETH_P_IP))
key->ipv4.addr.dst = ip_hdr(skb)->daddr;
else if (key->eth.type == htons(ETH_P_IPV6))
memcpy(&key->ipv6.addr.dst, &ipv6_hdr(skb)->daddr,
sizeof(key->ipv6.addr.dst));
else
return;
if (key->ip.proto == IPPROTO_UDP)
dst = udp_hdr(skb)->dest;
else if (key->ip.proto == IPPROTO_TCP)
dst = tcp_hdr(skb)->dest;
else if (key->ip.proto == IPPROTO_SCTP)
dst = sctp_hdr(skb)->dest;
else
return;
key->tp.dst = dst;
}
}
/* Returns NF_DROP if the packet should be dropped, NF_ACCEPT otherwise. */
static int ovs_ct_nat(struct net *net, struct sw_flow_key *key,
const struct ovs_conntrack_info *info,
struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo)
{
enum nf_nat_manip_type maniptype;
int err;
if (nf_ct_is_untracked(ct)) {
/* A NAT action may only be performed on tracked packets. */
return NF_ACCEPT;
}
/* Add NAT extension if not confirmed yet. */
if (!nf_ct_is_confirmed(ct) && !nf_ct_nat_ext_add(ct))
return NF_ACCEPT; /* Can't NAT. */
/* Determine NAT type.
* Check if the NAT type can be deduced from the tracked connection.
* Make sure new expected connections (IP_CT_RELATED) are NATted only
* when committing.
*/
if (info->nat & OVS_CT_NAT && ctinfo != IP_CT_NEW &&
ct->status & IPS_NAT_MASK &&
(ctinfo != IP_CT_RELATED || info->commit)) {
/* NAT an established or related connection like before. */
if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY)
/* This is the REPLY direction for a connection
* for which NAT was applied in the forward
* direction. Do the reverse NAT.
*/
maniptype = ct->status & IPS_SRC_NAT
? NF_NAT_MANIP_DST : NF_NAT_MANIP_SRC;
else
maniptype = ct->status & IPS_SRC_NAT
? NF_NAT_MANIP_SRC : NF_NAT_MANIP_DST;
} else if (info->nat & OVS_CT_SRC_NAT) {
maniptype = NF_NAT_MANIP_SRC;
} else if (info->nat & OVS_CT_DST_NAT) {
maniptype = NF_NAT_MANIP_DST;
} else {
return NF_ACCEPT; /* Connection is not NATed. */
}
err = ovs_ct_nat_execute(skb, ct, ctinfo, &info->range, maniptype);
/* Mark NAT done if successful and update the flow key. */
if (err == NF_ACCEPT)
ovs_nat_update_key(key, skb, maniptype);
return err;
}
#else /* !CONFIG_NF_NAT_NEEDED */
static int ovs_ct_nat(struct net *net, struct sw_flow_key *key,
const struct ovs_conntrack_info *info,
struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo)
{
return NF_ACCEPT;
}
#endif
/* Pass 'skb' through conntrack in 'net', using zone configured in 'info', if
* not done already. Update key with new CT state after passing the packet
* through conntrack.
* Note that if the packet is deemed invalid by conntrack, skb->nfct will be
* set to NULL and 0 will be returned.
*/
static int __ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
const struct ovs_conntrack_info *info,
struct sk_buff *skb)
{
/* If we are recirculating packets to match on conntrack fields and
* committing with a separate conntrack action, then we don't need to
* actually run the packet through conntrack twice unless it's for a
* different zone.
*/
bool cached = skb_nfct_cached(net, key, info, skb);
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
if (!cached) {
struct nf_conn *tmpl = info->ct;
int err;
/* Associate skb with specified zone. */
if (tmpl) {
if (skb_nfct(skb))
nf_conntrack_put(skb_nfct(skb));
nf_conntrack_get(&tmpl->ct_general);
nf_ct_set(skb, tmpl, IP_CT_NEW);
}
err = nf_conntrack_in(net, info->family,
NF_INET_PRE_ROUTING, skb);
if (err != NF_ACCEPT)
return -ENOENT;
/* Clear CT state NAT flags to mark that we have not yet done
* NAT after the nf_conntrack_in() call. We can actually clear
* the whole state, as it will be re-initialized below.
*/
key->ct.state = 0;
/* Update the key, but keep the NAT flags. */
ovs_ct_update_key(skb, info, key, true, true);
}
ct = nf_ct_get(skb, &ctinfo);
if (ct) {
/* Packets starting a new connection must be NATted before the
* helper, so that the helper knows about the NAT. We enforce
* this by delaying both NAT and helper calls for unconfirmed
* connections until the committing CT action. For later
* packets NAT and Helper may be called in either order.
*
* NAT will be done only if the CT action has NAT, and only
* once per packet (per zone), as guarded by the NAT bits in
* the key->ct.state.
*/
if (info->nat && !(key->ct.state & OVS_CS_F_NAT_MASK) &&
(nf_ct_is_confirmed(ct) || info->commit) &&
ovs_ct_nat(net, key, info, skb, ct, ctinfo) != NF_ACCEPT) {
return -EINVAL;
}
/* Userspace may decide to perform a ct lookup without a helper
* specified followed by a (recirculate and) commit with one.
* Therefore, for unconfirmed connections which we will commit,
* we need to attach the helper here.
*/
if (!nf_ct_is_confirmed(ct) && info->commit &&
info->helper && !nfct_help(ct)) {
int err = __nf_ct_try_assign_helper(ct, info->ct,
GFP_ATOMIC);
if (err)
return err;
}
/* Call the helper only if:
* - nf_conntrack_in() was executed above ("!cached") for a
* confirmed connection, or
* - When committing an unconfirmed connection.
*/
if ((nf_ct_is_confirmed(ct) ? !cached : info->commit) &&
ovs_ct_helper(skb, info->family) != NF_ACCEPT) {
return -EINVAL;
}
}
return 0;
}
/* Lookup connection and read fields into key. */
static int ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
const struct ovs_conntrack_info *info,
struct sk_buff *skb)
{
struct nf_conntrack_expect *exp;
/* If we pass an expected packet through nf_conntrack_in() the
* expectation is typically removed, but the packet could still be
* lost in upcall processing. To prevent this from happening we
* perform an explicit expectation lookup. Expected connections are
* always new, and will be passed through conntrack only when they are
* committed, as it is OK to remove the expectation at that time.
*/
exp = ovs_ct_expect_find(net, &info->zone, info->family, skb);
if (exp) {
u8 state;
/* NOTE: New connections are NATted and Helped only when
* committed, so we are not calling into NAT here.
*/
state = OVS_CS_F_TRACKED | OVS_CS_F_NEW | OVS_CS_F_RELATED;
__ovs_ct_update_key(key, state, &info->zone, exp->master);
} else {
struct nf_conn *ct;
int err;
err = __ovs_ct_lookup(net, key, info, skb);
if (err)
return err;
ct = (struct nf_conn *)skb_nfct(skb);
if (ct)
nf_ct_deliver_cached_events(ct);
}
return 0;
}
static bool labels_nonzero(const struct ovs_key_ct_labels *labels)
{
size_t i;
for (i = 0; i < sizeof(*labels); i++)
if (labels->ct_labels[i])
return true;
return false;
}
/* Lookup connection and confirm if unconfirmed. */
static int ovs_ct_commit(struct net *net, struct sw_flow_key *key,
const struct ovs_conntrack_info *info,
struct sk_buff *skb)
{
int err;
err = __ovs_ct_lookup(net, key, info, skb);
if (err)
return err;
/* Apply changes before confirming the connection so that the initial
* conntrack NEW netlink event carries the values given in the CT
* action.
*/
if (info->mark.mask) {
err = ovs_ct_set_mark(skb, key, info->mark.value,
info->mark.mask);
if (err)
return err;
}
if (labels_nonzero(&info->labels.mask)) {
err = ovs_ct_set_labels(skb, key, &info->labels.value,
&info->labels.mask);
if (err)
return err;
}
/* This will take care of sending queued events even if the connection
* is already confirmed.
*/
if (nf_conntrack_confirm(skb) != NF_ACCEPT)
return -EINVAL;
return 0;
}
/* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero
* value if 'skb' is freed.
*/
int ovs_ct_execute(struct net *net, struct sk_buff *skb,
struct sw_flow_key *key,
const struct ovs_conntrack_info *info)
{
int nh_ofs;
int err;
/* The conntrack module expects to be working at L3. */
nh_ofs = skb_network_offset(skb);
skb_pull_rcsum(skb, nh_ofs);
if (key->ip.frag != OVS_FRAG_TYPE_NONE) {
err = handle_fragments(net, key, info->zone.id, skb);
if (err)
return err;
}
if (info->commit)
err = ovs_ct_commit(net, key, info, skb);
else
err = ovs_ct_lookup(net, key, info, skb);
skb_push(skb, nh_ofs);
skb_postpush_rcsum(skb, skb->data, nh_ofs);
if (err)
kfree_skb(skb);
return err;
}
static int ovs_ct_add_helper(struct ovs_conntrack_info *info, const char *name,
const struct sw_flow_key *key, bool log)
{
struct nf_conntrack_helper *helper;
struct nf_conn_help *help;
helper = nf_conntrack_helper_try_module_get(name, info->family,
key->ip.proto);
if (!helper) {
OVS_NLERR(log, "Unknown helper \"%s\"", name);
return -EINVAL;
}
help = nf_ct_helper_ext_add(info->ct, helper, GFP_KERNEL);
if (!help) {
module_put(helper->me);
return -ENOMEM;
}
rcu_assign_pointer(help->helper, helper);
info->helper = helper;
return 0;
}
#ifdef CONFIG_NF_NAT_NEEDED
static int parse_nat(const struct nlattr *attr,
struct ovs_conntrack_info *info, bool log)
{
struct nlattr *a;
int rem;
bool have_ip_max = false;
bool have_proto_max = false;
bool ip_vers = (info->family == NFPROTO_IPV6);
nla_for_each_nested(a, attr, rem) {
static const int ovs_nat_attr_lens[OVS_NAT_ATTR_MAX + 1][2] = {
[OVS_NAT_ATTR_SRC] = {0, 0},
[OVS_NAT_ATTR_DST] = {0, 0},
[OVS_NAT_ATTR_IP_MIN] = {sizeof(struct in_addr),
sizeof(struct in6_addr)},
[OVS_NAT_ATTR_IP_MAX] = {sizeof(struct in_addr),
sizeof(struct in6_addr)},
[OVS_NAT_ATTR_PROTO_MIN] = {sizeof(u16), sizeof(u16)},
[OVS_NAT_ATTR_PROTO_MAX] = {sizeof(u16), sizeof(u16)},
[OVS_NAT_ATTR_PERSISTENT] = {0, 0},
[OVS_NAT_ATTR_PROTO_HASH] = {0, 0},
[OVS_NAT_ATTR_PROTO_RANDOM] = {0, 0},
};
int type = nla_type(a);
if (type > OVS_NAT_ATTR_MAX) {
OVS_NLERR(log,
"Unknown NAT attribute (type=%d, max=%d).\n",
type, OVS_NAT_ATTR_MAX);
return -EINVAL;
}
if (nla_len(a) != ovs_nat_attr_lens[type][ip_vers]) {
OVS_NLERR(log,
"NAT attribute type %d has unexpected length (%d != %d).\n",
type, nla_len(a),
ovs_nat_attr_lens[type][ip_vers]);
return -EINVAL;
}
switch (type) {
case OVS_NAT_ATTR_SRC:
case OVS_NAT_ATTR_DST:
if (info->nat) {
OVS_NLERR(log,
"Only one type of NAT may be specified.\n"
);
return -ERANGE;
}
info->nat |= OVS_CT_NAT;
info->nat |= ((type == OVS_NAT_ATTR_SRC)
? OVS_CT_SRC_NAT : OVS_CT_DST_NAT);
break;
case OVS_NAT_ATTR_IP_MIN:
nla_memcpy(&info->range.min_addr, a,
sizeof(info->range.min_addr));
info->range.flags |= NF_NAT_RANGE_MAP_IPS;
break;
case OVS_NAT_ATTR_IP_MAX:
have_ip_max = true;
nla_memcpy(&info->range.max_addr, a,
sizeof(info->range.max_addr));
info->range.flags |= NF_NAT_RANGE_MAP_IPS;
break;
case OVS_NAT_ATTR_PROTO_MIN:
info->range.min_proto.all = htons(nla_get_u16(a));
info->range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
break;
case OVS_NAT_ATTR_PROTO_MAX:
have_proto_max = true;
info->range.max_proto.all = htons(nla_get_u16(a));
info->range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
break;
case OVS_NAT_ATTR_PERSISTENT:
info->range.flags |= NF_NAT_RANGE_PERSISTENT;
break;
case OVS_NAT_ATTR_PROTO_HASH:
info->range.flags |= NF_NAT_RANGE_PROTO_RANDOM;
break;
case OVS_NAT_ATTR_PROTO_RANDOM:
info->range.flags |= NF_NAT_RANGE_PROTO_RANDOM_FULLY;
break;
default:
OVS_NLERR(log, "Unknown nat attribute (%d).\n", type);
return -EINVAL;
}
}
if (rem > 0) {
OVS_NLERR(log, "NAT attribute has %d unknown bytes.\n", rem);
return -EINVAL;
}
if (!info->nat) {
/* Do not allow flags if no type is given. */
if (info->range.flags) {
OVS_NLERR(log,
"NAT flags may be given only when NAT range (SRC or DST) is also specified.\n"
);
return -EINVAL;
}
info->nat = OVS_CT_NAT; /* NAT existing connections. */
} else if (!info->commit) {
OVS_NLERR(log,
"NAT attributes may be specified only when CT COMMIT flag is also specified.\n"
);
return -EINVAL;
}
/* Allow missing IP_MAX. */
if (info->range.flags & NF_NAT_RANGE_MAP_IPS && !have_ip_max) {
memcpy(&info->range.max_addr, &info->range.min_addr,
sizeof(info->range.max_addr));
}
/* Allow missing PROTO_MAX. */
if (info->range.flags & NF_NAT_RANGE_PROTO_SPECIFIED &&
!have_proto_max) {
info->range.max_proto.all = info->range.min_proto.all;
}
return 0;
}
#endif
static const struct ovs_ct_len_tbl ovs_ct_attr_lens[OVS_CT_ATTR_MAX + 1] = {
[OVS_CT_ATTR_COMMIT] = { .minlen = 0, .maxlen = 0 },
[OVS_CT_ATTR_ZONE] = { .minlen = sizeof(u16),
.maxlen = sizeof(u16) },
[OVS_CT_ATTR_MARK] = { .minlen = sizeof(struct md_mark),
.maxlen = sizeof(struct md_mark) },
[OVS_CT_ATTR_LABELS] = { .minlen = sizeof(struct md_labels),
.maxlen = sizeof(struct md_labels) },
[OVS_CT_ATTR_HELPER] = { .minlen = 1,
.maxlen = NF_CT_HELPER_NAME_LEN },
#ifdef CONFIG_NF_NAT_NEEDED
/* NAT length is checked when parsing the nested attributes. */
[OVS_CT_ATTR_NAT] = { .minlen = 0, .maxlen = INT_MAX },
#endif
};
static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info,
const char **helper, bool log)
{
struct nlattr *a;
int rem;
nla_for_each_nested(a, attr, rem) {
int type = nla_type(a);
int maxlen = ovs_ct_attr_lens[type].maxlen;
int minlen = ovs_ct_attr_lens[type].minlen;
if (type > OVS_CT_ATTR_MAX) {
OVS_NLERR(log,
"Unknown conntrack attr (type=%d, max=%d)",
type, OVS_CT_ATTR_MAX);
return -EINVAL;
}
if (nla_len(a) < minlen || nla_len(a) > maxlen) {
OVS_NLERR(log,
"Conntrack attr type has unexpected length (type=%d, length=%d, expected=%d)",
type, nla_len(a), maxlen);
return -EINVAL;
}
switch (type) {
case OVS_CT_ATTR_COMMIT:
info->commit = true;
break;
#ifdef CONFIG_NF_CONNTRACK_ZONES
case OVS_CT_ATTR_ZONE:
info->zone.id = nla_get_u16(a);
break;
#endif
#ifdef CONFIG_NF_CONNTRACK_MARK
case OVS_CT_ATTR_MARK: {
struct md_mark *mark = nla_data(a);
if (!mark->mask) {
OVS_NLERR(log, "ct_mark mask cannot be 0");
return -EINVAL;
}
info->mark = *mark;
break;
}
#endif
#ifdef CONFIG_NF_CONNTRACK_LABELS
case OVS_CT_ATTR_LABELS: {
struct md_labels *labels = nla_data(a);
if (!labels_nonzero(&labels->mask)) {
OVS_NLERR(log, "ct_labels mask cannot be 0");
return -EINVAL;
}
info->labels = *labels;
break;
}
#endif
case OVS_CT_ATTR_HELPER:
*helper = nla_data(a);
if (!memchr(*helper, '\0', nla_len(a))) {
OVS_NLERR(log, "Invalid conntrack helper");
return -EINVAL;
}
break;
#ifdef CONFIG_NF_NAT_NEEDED
case OVS_CT_ATTR_NAT: {
int err = parse_nat(a, info, log);
if (err)
return err;
break;
}
#endif
default:
OVS_NLERR(log, "Unknown conntrack attr (%d)",
type);
return -EINVAL;
}
}
#ifdef CONFIG_NF_CONNTRACK_MARK
if (!info->commit && info->mark.mask) {
OVS_NLERR(log,
"Setting conntrack mark requires 'commit' flag.");
return -EINVAL;
}
#endif
#ifdef CONFIG_NF_CONNTRACK_LABELS
if (!info->commit && labels_nonzero(&info->labels.mask)) {
OVS_NLERR(log,
"Setting conntrack labels requires 'commit' flag.");
return -EINVAL;
}
#endif
if (rem > 0) {
OVS_NLERR(log, "Conntrack attr has %d unknown bytes", rem);
return -EINVAL;
}
return 0;
}
bool ovs_ct_verify(struct net *net, enum ovs_key_attr attr)
{
if (attr == OVS_KEY_ATTR_CT_STATE)
return true;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
attr == OVS_KEY_ATTR_CT_ZONE)
return true;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) &&
attr == OVS_KEY_ATTR_CT_MARK)
return true;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
attr == OVS_KEY_ATTR_CT_LABELS) {
struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
return ovs_net->xt_label;
}
return false;
}
int ovs_ct_copy_action(struct net *net, const struct nlattr *attr,
const struct sw_flow_key *key,
struct sw_flow_actions **sfa, bool log)
{
struct ovs_conntrack_info ct_info;
const char *helper = NULL;
u16 family;
int err;
family = key_to_nfproto(key);
if (family == NFPROTO_UNSPEC) {
OVS_NLERR(log, "ct family unspecified");
return -EINVAL;
}
memset(&ct_info, 0, sizeof(ct_info));
ct_info.family = family;
nf_ct_zone_init(&ct_info.zone, NF_CT_DEFAULT_ZONE_ID,
NF_CT_DEFAULT_ZONE_DIR, 0);
err = parse_ct(attr, &ct_info, &helper, log);
if (err)
return err;
/* Set up template for tracking connections in specific zones. */
ct_info.ct = nf_ct_tmpl_alloc(net, &ct_info.zone, GFP_KERNEL);
if (!ct_info.ct) {
OVS_NLERR(log, "Failed to allocate conntrack template");
return -ENOMEM;
}
__set_bit(IPS_CONFIRMED_BIT, &ct_info.ct->status);
nf_conntrack_get(&ct_info.ct->ct_general);
if (helper) {
err = ovs_ct_add_helper(&ct_info, helper, key, log);
if (err)
goto err_free_ct;
}
err = ovs_nla_add_action(sfa, OVS_ACTION_ATTR_CT, &ct_info,
sizeof(ct_info), log);
if (err)
goto err_free_ct;
return 0;
err_free_ct:
__ovs_ct_free_action(&ct_info);
return err;
}
#ifdef CONFIG_NF_NAT_NEEDED
static bool ovs_ct_nat_to_attr(const struct ovs_conntrack_info *info,
struct sk_buff *skb)
{
struct nlattr *start;
start = nla_nest_start(skb, OVS_CT_ATTR_NAT);
if (!start)
return false;
if (info->nat & OVS_CT_SRC_NAT) {
if (nla_put_flag(skb, OVS_NAT_ATTR_SRC))
return false;
} else if (info->nat & OVS_CT_DST_NAT) {
if (nla_put_flag(skb, OVS_NAT_ATTR_DST))
return false;
} else {
goto out;
}
if (info->range.flags & NF_NAT_RANGE_MAP_IPS) {
if (IS_ENABLED(CONFIG_NF_NAT_IPV4) &&
info->family == NFPROTO_IPV4) {
if (nla_put_in_addr(skb, OVS_NAT_ATTR_IP_MIN,
info->range.min_addr.ip) ||
(info->range.max_addr.ip
!= info->range.min_addr.ip &&
(nla_put_in_addr(skb, OVS_NAT_ATTR_IP_MAX,
info->range.max_addr.ip))))
return false;
} else if (IS_ENABLED(CONFIG_NF_NAT_IPV6) &&
info->family == NFPROTO_IPV6) {
if (nla_put_in6_addr(skb, OVS_NAT_ATTR_IP_MIN,
&info->range.min_addr.in6) ||
(memcmp(&info->range.max_addr.in6,
&info->range.min_addr.in6,
sizeof(info->range.max_addr.in6)) &&
(nla_put_in6_addr(skb, OVS_NAT_ATTR_IP_MAX,
&info->range.max_addr.in6))))
return false;
} else {
return false;
}
}
if (info->range.flags & NF_NAT_RANGE_PROTO_SPECIFIED &&
(nla_put_u16(skb, OVS_NAT_ATTR_PROTO_MIN,
ntohs(info->range.min_proto.all)) ||
(info->range.max_proto.all != info->range.min_proto.all &&
nla_put_u16(skb, OVS_NAT_ATTR_PROTO_MAX,
ntohs(info->range.max_proto.all)))))
return false;
if (info->range.flags & NF_NAT_RANGE_PERSISTENT &&
nla_put_flag(skb, OVS_NAT_ATTR_PERSISTENT))
return false;
if (info->range.flags & NF_NAT_RANGE_PROTO_RANDOM &&
nla_put_flag(skb, OVS_NAT_ATTR_PROTO_HASH))
return false;
if (info->range.flags & NF_NAT_RANGE_PROTO_RANDOM_FULLY &&
nla_put_flag(skb, OVS_NAT_ATTR_PROTO_RANDOM))
return false;
out:
nla_nest_end(skb, start);
return true;
}
#endif
int ovs_ct_action_to_attr(const struct ovs_conntrack_info *ct_info,
struct sk_buff *skb)
{
struct nlattr *start;
start = nla_nest_start(skb, OVS_ACTION_ATTR_CT);
if (!start)
return -EMSGSIZE;
if (ct_info->commit && nla_put_flag(skb, OVS_CT_ATTR_COMMIT))
return -EMSGSIZE;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
nla_put_u16(skb, OVS_CT_ATTR_ZONE, ct_info->zone.id))
return -EMSGSIZE;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) && ct_info->mark.mask &&
nla_put(skb, OVS_CT_ATTR_MARK, sizeof(ct_info->mark),
&ct_info->mark))
return -EMSGSIZE;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
labels_nonzero(&ct_info->labels.mask) &&
nla_put(skb, OVS_CT_ATTR_LABELS, sizeof(ct_info->labels),
&ct_info->labels))
return -EMSGSIZE;
if (ct_info->helper) {
if (nla_put_string(skb, OVS_CT_ATTR_HELPER,
ct_info->helper->name))
return -EMSGSIZE;
}
#ifdef CONFIG_NF_NAT_NEEDED
if (ct_info->nat && !ovs_ct_nat_to_attr(ct_info, skb))
return -EMSGSIZE;
#endif
nla_nest_end(skb, start);
return 0;
}
void ovs_ct_free_action(const struct nlattr *a)
{
struct ovs_conntrack_info *ct_info = nla_data(a);
__ovs_ct_free_action(ct_info);
}
static void __ovs_ct_free_action(struct ovs_conntrack_info *ct_info)
{
if (ct_info->helper)
module_put(ct_info->helper->me);
if (ct_info->ct)
nf_ct_tmpl_free(ct_info->ct);
}
void ovs_ct_init(struct net *net)
{
unsigned int n_bits = sizeof(struct ovs_key_ct_labels) * BITS_PER_BYTE;
struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
if (nf_connlabels_get(net, n_bits - 1)) {
ovs_net->xt_label = false;
OVS_NLERR(true, "Failed to set connlabel length");
} else {
ovs_net->xt_label = true;
}
}
void ovs_ct_exit(struct net *net)
{
struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
if (ovs_net->xt_label)
nf_connlabels_put(net);
}
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