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linux_dsm_epyc7002/net/rxrpc/input.c
David Howells 248f219cb8 rxrpc: Rewrite the data and ack handling code 
Rewrite the data and ack handling code such that:

 (1) Parsing of received ACK and ABORT packets and the distribution and the
     filing of DATA packets happens entirely within the data_ready context
     called from the UDP socket.  This allows us to process and discard ACK
     and ABORT packets much more quickly (they're no longer stashed on a
     queue for a background thread to process).

 (2) We avoid calling skb_clone(), pskb_pull() and pskb_trim().  We instead
     keep track of the offset and length of the content of each packet in
     the sk_buff metadata.  This means we don't do any allocation in the
     receive path.

 (3) Jumbo DATA packet parsing is now done in data_ready context.  Rather
     than cloning the packet once for each subpacket and pulling/trimming
     it, we file the packet multiple times with an annotation for each
     indicating which subpacket is there.  From that we can directly
     calculate the offset and length.

 (4) A call's receive queue can be accessed without taking locks (memory
     barriers do have to be used, though).

 (5) Incoming calls are set up from preallocated resources and immediately
     made live.  They can than have packets queued upon them and ACKs
     generated.  If insufficient resources exist, DATA packet #1 is given a
     BUSY reply and other DATA packets are discarded).

 (6) sk_buffs no longer take a ref on their parent call.

To make this work, the following changes are made:

 (1) Each call's receive buffer is now a circular buffer of sk_buff
     pointers (rxtx_buffer) rather than a number of sk_buff_heads spread
     between the call and the socket.  This permits each sk_buff to be in
     the buffer multiple times.  The receive buffer is reused for the
     transmit buffer.

 (2) A circular buffer of annotations (rxtx_annotations) is kept parallel
     to the data buffer.  Transmission phase annotations indicate whether a
     buffered packet has been ACK'd or not and whether it needs
     retransmission.

     Receive phase annotations indicate whether a slot holds a whole packet
     or a jumbo subpacket and, if the latter, which subpacket.  They also
     note whether the packet has been decrypted in place.

 (3) DATA packet window tracking is much simplified.  Each phase has just
     two numbers representing the window (rx_hard_ack/rx_top and
     tx_hard_ack/tx_top).

     The hard_ack number is the sequence number before base of the window,
     representing the last packet the other side says it has consumed.
     hard_ack starts from 0 and the first packet is sequence number 1.

     The top number is the sequence number of the highest-numbered packet
     residing in the buffer.  Packets between hard_ack+1 and top are
     soft-ACK'd to indicate they've been received, but not yet consumed.

     Four macros, before(), before_eq(), after() and after_eq() are added
     to compare sequence numbers within the window.  This allows for the
     top of the window to wrap when the hard-ack sequence number gets close
     to the limit.

     Two flags, RXRPC_CALL_RX_LAST and RXRPC_CALL_TX_LAST, are added also
     to indicate when rx_top and tx_top point at the packets with the
     LAST_PACKET bit set, indicating the end of the phase.

 (4) Calls are queued on the socket 'receive queue' rather than packets.
     This means that we don't need have to invent dummy packets to queue to
     indicate abnormal/terminal states and we don't have to keep metadata
     packets (such as ABORTs) around

 (5) The offset and length of a (sub)packet's content are now passed to
     the verify_packet security op.  This is currently expected to decrypt
     the packet in place and validate it.

     However, there's now nowhere to store the revised offset and length of
     the actual data within the decrypted blob (there may be a header and
     padding to skip) because an sk_buff may represent multiple packets, so
     a locate_data security op is added to retrieve these details from the
     sk_buff content when needed.

 (6) recvmsg() now has to handle jumbo subpackets, where each subpacket is
     individually secured and needs to be individually decrypted.  The code
     to do this is broken out into rxrpc_recvmsg_data() and shared with the
     kernel API.  It now iterates over the call's receive buffer rather
     than walking the socket receive queue.

Additional changes:

 (1) The timers are condensed to a single timer that is set for the soonest
     of three timeouts (delayed ACK generation, DATA retransmission and
     call lifespan).

 (2) Transmission of ACK and ABORT packets is effected immediately from
     process-context socket ops/kernel API calls that cause them instead of
     them being punted off to a background work item.  The data_ready
     handler still has to defer to the background, though.

 (3) A shutdown op is added to the AF_RXRPC socket so that the AFS
     filesystem can shut down the socket and flush its own work items
     before closing the socket to deal with any in-progress service calls.

Future additional changes that will need to be considered:

 (1) Make sure that a call doesn't hog the front of the queue by receiving
     data from the network as fast as userspace is consuming it to the
     exclusion of other calls.

 (2) Transmit delayed ACKs from within recvmsg() when we've consumed
     sufficiently more packets to avoid the background work item needing to
     run.

Signed-off-by: David Howells <dhowells@redhat.com>
2016-09-08 11:10:12 +01:00

830 lines
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C
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/* RxRPC packet reception
*
* Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/errqueue.h>
#include <linux/udp.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/icmp.h>
#include <linux/gfp.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <net/ip.h>
#include <net/udp.h>
#include <net/net_namespace.h>
#include "ar-internal.h"
static void rxrpc_proto_abort(const char *why,
struct rxrpc_call *call, rxrpc_seq_t seq)
{
if (rxrpc_abort_call(why, call, seq, RX_PROTOCOL_ERROR, EBADMSG)) {
set_bit(RXRPC_CALL_EV_ABORT, &call->events);
rxrpc_queue_call(call);
}
}
/*
* Apply a hard ACK by advancing the Tx window.
*/
static void rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to)
{
struct sk_buff *skb, *list = NULL;
int ix;
spin_lock(&call->lock);
while (before(call->tx_hard_ack, to)) {
call->tx_hard_ack++;
ix = call->tx_hard_ack & RXRPC_RXTX_BUFF_MASK;
skb = call->rxtx_buffer[ix];
rxrpc_see_skb(skb);
call->rxtx_buffer[ix] = NULL;
call->rxtx_annotations[ix] = 0;
skb->next = list;
list = skb;
}
spin_unlock(&call->lock);
while (list) {
skb = list;
list = skb->next;
skb->next = NULL;
rxrpc_free_skb(skb);
}
}
/*
* End the transmission phase of a call.
*
* This occurs when we get an ACKALL packet, the first DATA packet of a reply,
* or a final ACK packet.
*/
static bool rxrpc_end_tx_phase(struct rxrpc_call *call, const char *abort_why)
{
_enter("");
switch (call->state) {
case RXRPC_CALL_CLIENT_RECV_REPLY:
return true;
case RXRPC_CALL_CLIENT_AWAIT_REPLY:
case RXRPC_CALL_SERVER_AWAIT_ACK:
break;
default:
rxrpc_proto_abort(abort_why, call, call->tx_top);
return false;
}
rxrpc_rotate_tx_window(call, call->tx_top);
write_lock(&call->state_lock);
switch (call->state) {
default:
break;
case RXRPC_CALL_CLIENT_AWAIT_REPLY:
call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
break;
case RXRPC_CALL_SERVER_AWAIT_ACK:
__rxrpc_call_completed(call);
rxrpc_notify_socket(call);
break;
}
write_unlock(&call->state_lock);
_leave(" = ok");
return true;
}
/*
* Scan a jumbo packet to validate its structure and to work out how many
* subpackets it contains.
*
* A jumbo packet is a collection of consecutive packets glued together with
* little headers between that indicate how to change the initial header for
* each subpacket.
*
* RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
* the last are RXRPC_JUMBO_DATALEN in size. The last subpacket may be of any
* size.
*/
static bool rxrpc_validate_jumbo(struct sk_buff *skb)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
unsigned int offset = sp->offset;
unsigned int len = skb->data_len;
int nr_jumbo = 1;
u8 flags = sp->hdr.flags;
do {
nr_jumbo++;
if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
goto protocol_error;
if (flags & RXRPC_LAST_PACKET)
goto protocol_error;
offset += RXRPC_JUMBO_DATALEN;
if (skb_copy_bits(skb, offset, &flags, 1) < 0)
goto protocol_error;
offset += sizeof(struct rxrpc_jumbo_header);
} while (flags & RXRPC_JUMBO_PACKET);
sp->nr_jumbo = nr_jumbo;
return true;
protocol_error:
return false;
}
/*
* Handle reception of a duplicate packet.
*
* We have to take care to avoid an attack here whereby we're given a series of
* jumbograms, each with a sequence number one before the preceding one and
* filled up to maximum UDP size. If they never send us the first packet in
* the sequence, they can cause us to have to hold on to around 2MiB of kernel
* space until the call times out.
*
* We limit the space usage by only accepting three duplicate jumbo packets per
* call. After that, we tell the other side we're no longer accepting jumbos
* (that information is encoded in the ACK packet).
*/
static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
u8 annotation, bool *_jumbo_dup)
{
/* Discard normal packets that are duplicates. */
if (annotation == 0)
return;
/* Skip jumbo subpackets that are duplicates. When we've had three or
* more partially duplicate jumbo packets, we refuse to take any more
* jumbos for this call.
*/
if (!*_jumbo_dup) {
call->nr_jumbo_dup++;
*_jumbo_dup = true;
}
}
/*
* Process a DATA packet, adding the packet to the Rx ring.
*/
static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb,
u16 skew)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
unsigned int offset = sp->offset;
unsigned int ix;
rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0;
rxrpc_seq_t seq = sp->hdr.seq, hard_ack;
bool immediate_ack = false, jumbo_dup = false, queued;
u16 len;
u8 ack = 0, flags, annotation = 0;
_enter("{%u,%u},{%u,%u}",
call->rx_hard_ack, call->rx_top, skb->data_len, seq);
_proto("Rx DATA %%%u { #%u f=%02x }",
sp->hdr.serial, seq, sp->hdr.flags);
if (call->state >= RXRPC_CALL_COMPLETE)
return;
/* Received data implicitly ACKs all of the request packets we sent
* when we're acting as a client.
*/
if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY &&
!rxrpc_end_tx_phase(call, "ETD"))
return;
call->ackr_prev_seq = seq;
hard_ack = READ_ONCE(call->rx_hard_ack);
if (after(seq, hard_ack + call->rx_winsize)) {
ack = RXRPC_ACK_EXCEEDS_WINDOW;
ack_serial = serial;
goto ack;
}
flags = sp->hdr.flags;
if (flags & RXRPC_JUMBO_PACKET) {
if (call->nr_jumbo_dup > 3) {
ack = RXRPC_ACK_NOSPACE;
ack_serial = serial;
goto ack;
}
annotation = 1;
}
next_subpacket:
queued = false;
ix = seq & RXRPC_RXTX_BUFF_MASK;
len = skb->data_len;
if (flags & RXRPC_JUMBO_PACKET)
len = RXRPC_JUMBO_DATALEN;
if (flags & RXRPC_LAST_PACKET) {
if (test_and_set_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
seq != call->rx_top)
return rxrpc_proto_abort("LSN", call, seq);
} else {
if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
after_eq(seq, call->rx_top))
return rxrpc_proto_abort("LSA", call, seq);
}
if (before_eq(seq, hard_ack)) {
ack = RXRPC_ACK_DUPLICATE;
ack_serial = serial;
goto skip;
}
if (flags & RXRPC_REQUEST_ACK && !ack) {
ack = RXRPC_ACK_REQUESTED;
ack_serial = serial;
}
if (call->rxtx_buffer[ix]) {
rxrpc_input_dup_data(call, seq, annotation, &jumbo_dup);
if (ack != RXRPC_ACK_DUPLICATE) {
ack = RXRPC_ACK_DUPLICATE;
ack_serial = serial;
}
immediate_ack = true;
goto skip;
}
/* Queue the packet. We use a couple of memory barriers here as need
* to make sure that rx_top is perceived to be set after the buffer
* pointer and that the buffer pointer is set after the annotation and
* the skb data.
*
* Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
* and also rxrpc_fill_out_ack().
*/
rxrpc_get_skb(skb);
call->rxtx_annotations[ix] = annotation;
smp_wmb();
call->rxtx_buffer[ix] = skb;
if (after(seq, call->rx_top))
smp_store_release(&call->rx_top, seq);
queued = true;
if (after_eq(seq, call->rx_expect_next)) {
if (after(seq, call->rx_expect_next)) {
_net("OOS %u > %u", seq, call->rx_expect_next);
ack = RXRPC_ACK_OUT_OF_SEQUENCE;
ack_serial = serial;
}
call->rx_expect_next = seq + 1;
}
skip:
offset += len;
if (flags & RXRPC_JUMBO_PACKET) {
if (skb_copy_bits(skb, offset, &flags, 1) < 0)
return rxrpc_proto_abort("XJF", call, seq);
offset += sizeof(struct rxrpc_jumbo_header);
seq++;
serial++;
annotation++;
if (flags & RXRPC_JUMBO_PACKET)
annotation |= RXRPC_RX_ANNO_JLAST;
_proto("Rx DATA Jumbo %%%u", serial);
goto next_subpacket;
}
if (queued && flags & RXRPC_LAST_PACKET && !ack) {
ack = RXRPC_ACK_DELAY;
ack_serial = serial;
}
ack:
if (ack)
rxrpc_propose_ACK(call, ack, skew, ack_serial,
immediate_ack, true);
if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1)
rxrpc_notify_socket(call);
_leave(" [queued]");
}
/*
* Process the extra information that may be appended to an ACK packet
*/
static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
struct rxrpc_ackinfo *ackinfo)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
struct rxrpc_peer *peer;
unsigned int mtu;
_proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
sp->hdr.serial,
ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
ntohl(ackinfo->rwind), ntohl(ackinfo->jumbo_max));
if (call->tx_winsize > ntohl(ackinfo->rwind))
call->tx_winsize = ntohl(ackinfo->rwind);
mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
peer = call->peer;
if (mtu < peer->maxdata) {
spin_lock_bh(&peer->lock);
peer->maxdata = mtu;
peer->mtu = mtu + peer->hdrsize;
spin_unlock_bh(&peer->lock);
_net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
}
}
/*
* Process individual soft ACKs.
*
* Each ACK in the array corresponds to one packet and can be either an ACK or
* a NAK. If we get find an explicitly NAK'd packet we resend immediately;
* packets that lie beyond the end of the ACK list are scheduled for resend by
* the timer on the basis that the peer might just not have processed them at
* the time the ACK was sent.
*/
static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
rxrpc_seq_t seq, int nr_acks)
{
bool resend = false;
int ix;
for (; nr_acks > 0; nr_acks--, seq++) {
ix = seq & RXRPC_RXTX_BUFF_MASK;
switch (*acks) {
case RXRPC_ACK_TYPE_ACK:
call->rxtx_annotations[ix] = RXRPC_TX_ANNO_ACK;
break;
case RXRPC_ACK_TYPE_NACK:
if (call->rxtx_annotations[ix] == RXRPC_TX_ANNO_NAK)
continue;
call->rxtx_annotations[ix] = RXRPC_TX_ANNO_NAK;
resend = true;
break;
default:
return rxrpc_proto_abort("SFT", call, 0);
}
}
if (resend &&
!test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
rxrpc_queue_call(call);
}
/*
* Process an ACK packet.
*
* ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
* in the ACK array. Anything before that is hard-ACK'd and may be discarded.
*
* A hard-ACK means that a packet has been processed and may be discarded; a
* soft-ACK means that the packet may be discarded and retransmission
* requested. A phase is complete when all packets are hard-ACK'd.
*/
static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
u16 skew)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
union {
struct rxrpc_ackpacket ack;
struct rxrpc_ackinfo info;
u8 acks[RXRPC_MAXACKS];
} buf;
rxrpc_seq_t first_soft_ack, hard_ack;
int nr_acks, offset;
_enter("");
if (skb_copy_bits(skb, sp->offset, &buf.ack, sizeof(buf.ack)) < 0) {
_debug("extraction failure");
return rxrpc_proto_abort("XAK", call, 0);
}
sp->offset += sizeof(buf.ack);
first_soft_ack = ntohl(buf.ack.firstPacket);
hard_ack = first_soft_ack - 1;
nr_acks = buf.ack.nAcks;
_proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
sp->hdr.serial,
ntohs(buf.ack.maxSkew),
first_soft_ack,
ntohl(buf.ack.previousPacket),
ntohl(buf.ack.serial),
rxrpc_acks(buf.ack.reason),
buf.ack.nAcks);
if (buf.ack.reason == RXRPC_ACK_PING) {
_proto("Rx ACK %%%u PING Request", sp->hdr.serial);
rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
skew, sp->hdr.serial, true, true);
} else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
skew, sp->hdr.serial, true, true);
}
offset = sp->offset + nr_acks + 3;
if (skb->data_len >= offset + sizeof(buf.info)) {
if (skb_copy_bits(skb, offset, &buf.info, sizeof(buf.info)) < 0)
return rxrpc_proto_abort("XAI", call, 0);
rxrpc_input_ackinfo(call, skb, &buf.info);
}
if (first_soft_ack == 0)
return rxrpc_proto_abort("AK0", call, 0);
/* Ignore ACKs unless we are or have just been transmitting. */
switch (call->state) {
case RXRPC_CALL_CLIENT_SEND_REQUEST:
case RXRPC_CALL_CLIENT_AWAIT_REPLY:
case RXRPC_CALL_SERVER_SEND_REPLY:
case RXRPC_CALL_SERVER_AWAIT_ACK:
break;
default:
return;
}
/* Discard any out-of-order or duplicate ACKs. */
if ((int)sp->hdr.serial - (int)call->acks_latest <= 0) {
_debug("discard ACK %d <= %d",
sp->hdr.serial, call->acks_latest);
return;
}
call->acks_latest = sp->hdr.serial;
if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) &&
hard_ack == call->tx_top) {
rxrpc_end_tx_phase(call, "ETA");
return;
}
if (before(hard_ack, call->tx_hard_ack) ||
after(hard_ack, call->tx_top))
return rxrpc_proto_abort("AKW", call, 0);
if (after(hard_ack, call->tx_hard_ack))
rxrpc_rotate_tx_window(call, hard_ack);
if (after(first_soft_ack, call->tx_top))
return;
if (nr_acks > call->tx_top - first_soft_ack + 1)
nr_acks = first_soft_ack - call->tx_top + 1;
if (skb_copy_bits(skb, sp->offset, buf.acks, nr_acks) < 0)
return rxrpc_proto_abort("XSA", call, 0);
rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks);
}
/*
* Process an ACKALL packet.
*/
static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
_proto("Rx ACKALL %%%u", sp->hdr.serial);
rxrpc_end_tx_phase(call, "ETL");
}
/*
* Process an ABORT packet.
*/
static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
__be32 wtmp;
u32 abort_code = RX_CALL_DEAD;
_enter("");
if (skb->len >= 4 &&
skb_copy_bits(skb, sp->offset, &wtmp, sizeof(wtmp)) >= 0)
abort_code = ntohl(wtmp);
_proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
abort_code, ECONNABORTED))
rxrpc_notify_socket(call);
}
/*
* Process an incoming call packet.
*/
static void rxrpc_input_call_packet(struct rxrpc_call *call,
struct sk_buff *skb, u16 skew)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
_enter("%p,%p", call, skb);
switch (sp->hdr.type) {
case RXRPC_PACKET_TYPE_DATA:
rxrpc_input_data(call, skb, skew);
break;
case RXRPC_PACKET_TYPE_ACK:
rxrpc_input_ack(call, skb, skew);
break;
case RXRPC_PACKET_TYPE_BUSY:
_proto("Rx BUSY %%%u", sp->hdr.serial);
/* Just ignore BUSY packets from the server; the retry and
* lifespan timers will take care of business. BUSY packets
* from the client don't make sense.
*/
break;
case RXRPC_PACKET_TYPE_ABORT:
rxrpc_input_abort(call, skb);
break;
case RXRPC_PACKET_TYPE_ACKALL:
rxrpc_input_ackall(call, skb);
break;
default:
_proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial);
break;
}
_leave("");
}
/*
* post connection-level events to the connection
* - this includes challenges, responses, some aborts and call terminal packet
* retransmission.
*/
static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
struct sk_buff *skb)
{
_enter("%p,%p", conn, skb);
skb_queue_tail(&conn->rx_queue, skb);
rxrpc_queue_conn(conn);
}
/*
* post endpoint-level events to the local endpoint
* - this includes debug and version messages
*/
static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
struct sk_buff *skb)
{
_enter("%p,%p", local, skb);
skb_queue_tail(&local->event_queue, skb);
rxrpc_queue_local(local);
}
/*
* put a packet up for transport-level abort
*/
static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
{
CHECK_SLAB_OKAY(&local->usage);
skb_queue_tail(&local->reject_queue, skb);
rxrpc_queue_local(local);
}
/*
* Extract the wire header from a packet and translate the byte order.
*/
static noinline
int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
{
struct rxrpc_wire_header whdr;
/* dig out the RxRPC connection details */
if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
return -EBADMSG;
memset(sp, 0, sizeof(*sp));
sp->hdr.epoch = ntohl(whdr.epoch);
sp->hdr.cid = ntohl(whdr.cid);
sp->hdr.callNumber = ntohl(whdr.callNumber);
sp->hdr.seq = ntohl(whdr.seq);
sp->hdr.serial = ntohl(whdr.serial);
sp->hdr.flags = whdr.flags;
sp->hdr.type = whdr.type;
sp->hdr.userStatus = whdr.userStatus;
sp->hdr.securityIndex = whdr.securityIndex;
sp->hdr._rsvd = ntohs(whdr._rsvd);
sp->hdr.serviceId = ntohs(whdr.serviceId);
sp->offset = sizeof(whdr);
return 0;
}
/*
* handle data received on the local endpoint
* - may be called in interrupt context
*
* The socket is locked by the caller and this prevents the socket from being
* shut down and the local endpoint from going away, thus sk_user_data will not
* be cleared until this function returns.
*/
void rxrpc_data_ready(struct sock *udp_sk)
{
struct rxrpc_connection *conn;
struct rxrpc_channel *chan;
struct rxrpc_call *call;
struct rxrpc_skb_priv *sp;
struct rxrpc_local *local = udp_sk->sk_user_data;
struct sk_buff *skb;
unsigned int channel;
int ret, skew;
_enter("%p", udp_sk);
ASSERT(!irqs_disabled());
skb = skb_recv_datagram(udp_sk, 0, 1, &ret);
if (!skb) {
if (ret == -EAGAIN)
return;
_debug("UDP socket error %d", ret);
return;
}
rxrpc_new_skb(skb);
_net("recv skb %p", skb);
/* we'll probably need to checksum it (didn't call sock_recvmsg) */
if (skb_checksum_complete(skb)) {
rxrpc_free_skb(skb);
__UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
_leave(" [CSUM failed]");
return;
}
__UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
/* The socket buffer we have is owned by UDP, with UDP's data all over
* it, but we really want our own data there.
*/
skb_orphan(skb);
sp = rxrpc_skb(skb);
_net("Rx UDP packet from %08x:%04hu",
ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));
/* dig out the RxRPC connection details */
if (rxrpc_extract_header(sp, skb) < 0)
goto bad_message;
trace_rxrpc_rx_packet(sp);
_net("Rx RxRPC %s ep=%x call=%x:%x",
sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
!((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
_proto("Rx Bad Packet Type %u", sp->hdr.type);
goto bad_message;
}
switch (sp->hdr.type) {
case RXRPC_PACKET_TYPE_VERSION:
rxrpc_post_packet_to_local(local, skb);
goto out;
case RXRPC_PACKET_TYPE_BUSY:
if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
goto discard;
case RXRPC_PACKET_TYPE_DATA:
if (sp->hdr.callNumber == 0)
goto bad_message;
if (sp->hdr.flags & RXRPC_JUMBO_PACKET &&
!rxrpc_validate_jumbo(skb))
goto bad_message;
break;
}
rcu_read_lock();
conn = rxrpc_find_connection_rcu(local, skb);
if (conn) {
if (sp->hdr.securityIndex != conn->security_ix)
goto wrong_security;
if (sp->hdr.callNumber == 0) {
/* Connection-level packet */
_debug("CONN %p {%d}", conn, conn->debug_id);
rxrpc_post_packet_to_conn(conn, skb);
goto out_unlock;
}
/* Note the serial number skew here */
skew = (int)sp->hdr.serial - (int)conn->hi_serial;
if (skew >= 0) {
if (skew > 0)
conn->hi_serial = sp->hdr.serial;
} else {
skew = -skew;
skew = min(skew, 65535);
}
/* Call-bound packets are routed by connection channel. */
channel = sp->hdr.cid & RXRPC_CHANNELMASK;
chan = &conn->channels[channel];
/* Ignore really old calls */
if (sp->hdr.callNumber < chan->last_call)
goto discard_unlock;
if (sp->hdr.callNumber == chan->last_call) {
/* For the previous service call, if completed successfully, we
* discard all further packets.
*/
if (rxrpc_conn_is_service(conn) &&
(chan->last_type == RXRPC_PACKET_TYPE_ACK ||
sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
goto discard_unlock;
/* But otherwise we need to retransmit the final packet from
* data cached in the connection record.
*/
rxrpc_post_packet_to_conn(conn, skb);
goto out_unlock;
}
call = rcu_dereference(chan->call);
} else {
skew = 0;
call = NULL;
}
if (!call || atomic_read(&call->usage) == 0) {
if (!(sp->hdr.type & RXRPC_CLIENT_INITIATED) ||
sp->hdr.callNumber == 0 ||
sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
goto bad_message_unlock;
if (sp->hdr.seq != 1)
goto discard_unlock;
call = rxrpc_new_incoming_call(local, conn, skb);
if (!call) {
rcu_read_unlock();
goto reject_packet;
}
}
rxrpc_input_call_packet(call, skb, skew);
goto discard_unlock;
discard_unlock:
rcu_read_unlock();
discard:
rxrpc_free_skb(skb);
out:
trace_rxrpc_rx_done(0, 0);
return;
out_unlock:
rcu_read_unlock();
goto out;
wrong_security:
rcu_read_unlock();
trace_rxrpc_abort("SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
RXKADINCONSISTENCY, EBADMSG);
skb->priority = RXKADINCONSISTENCY;
goto post_abort;
bad_message_unlock:
rcu_read_unlock();
bad_message:
trace_rxrpc_abort("BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
RX_PROTOCOL_ERROR, EBADMSG);
skb->priority = RX_PROTOCOL_ERROR;
post_abort:
skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
reject_packet:
trace_rxrpc_rx_done(skb->mark, skb->priority);
rxrpc_reject_packet(local, skb);
_leave(" [badmsg]");
}
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