linux/net/sctp/output.c

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/* SCTP kernel implementation
* (C) Copyright IBM Corp. 2001, 2004
* Copyright (c) 1999-2000 Cisco, Inc.
* Copyright (c) 1999-2001 Motorola, Inc.
*
* This file is part of the SCTP kernel implementation
*
* These functions handle output processing.
*
* This SCTP implementation 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, or (at your option)
* any later version.
*
* This SCTP implementation 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.
*
* You should have received a copy of the GNU General Public License
* along with GNU CC; see the file COPYING. If not, write to
* the Free Software Foundation, 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Please send any bug reports or fixes you make to the
* email address(es):
* lksctp developers <lksctp-developers@lists.sourceforge.net>
*
* Or submit a bug report through the following website:
* http://www.sf.net/projects/lksctp
*
* Written or modified by:
* La Monte H.P. Yarroll <piggy@acm.org>
* Karl Knutson <karl@athena.chicago.il.us>
* Jon Grimm <jgrimm@austin.ibm.com>
* Sridhar Samudrala <sri@us.ibm.com>
*
* Any bugs reported given to us we will try to fix... any fixes shared will
* be incorporated into the next SCTP release.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/wait.h>
#include <linux/time.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/init.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#include <net/inet_ecn.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/net_namespace.h>
#include <linux/socket.h> /* for sa_family_t */
#include <net/sock.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
#include <net/sctp/checksum.h>
/* Forward declarations for private helpers. */
static sctp_xmit_t __sctp_packet_append_chunk(struct sctp_packet *packet,
struct sctp_chunk *chunk);
static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet,
struct sctp_chunk *chunk);
static void sctp_packet_append_data(struct sctp_packet *packet,
struct sctp_chunk *chunk);
static sctp_xmit_t sctp_packet_will_fit(struct sctp_packet *packet,
struct sctp_chunk *chunk,
u16 chunk_len);
static void sctp_packet_reset(struct sctp_packet *packet)
{
packet->size = packet->overhead;
packet->has_cookie_echo = 0;
packet->has_sack = 0;
packet->has_data = 0;
packet->has_auth = 0;
packet->ipfragok = 0;
packet->auth = NULL;
}
/* Config a packet.
* This appears to be a followup set of initializations.
*/
struct sctp_packet *sctp_packet_config(struct sctp_packet *packet,
__u32 vtag, int ecn_capable)
{
struct sctp_chunk *chunk = NULL;
SCTP_DEBUG_PRINTK("%s: packet:%p vtag:0x%x\n", __func__,
packet, vtag);
packet->vtag = vtag;
if (ecn_capable && sctp_packet_empty(packet)) {
chunk = sctp_get_ecne_prepend(packet->transport->asoc);
/* If there a is a prepend chunk stick it on the list before
* any other chunks get appended.
*/
if (chunk)
sctp_packet_append_chunk(packet, chunk);
}
return packet;
}
/* Initialize the packet structure. */
struct sctp_packet *sctp_packet_init(struct sctp_packet *packet,
struct sctp_transport *transport,
__u16 sport, __u16 dport)
{
struct sctp_association *asoc = transport->asoc;
size_t overhead;
SCTP_DEBUG_PRINTK("%s: packet:%p transport:%p\n", __func__,
packet, transport);
packet->transport = transport;
packet->source_port = sport;
packet->destination_port = dport;
INIT_LIST_HEAD(&packet->chunk_list);
if (asoc) {
struct sctp_sock *sp = sctp_sk(asoc->base.sk);
overhead = sp->pf->af->net_header_len;
} else {
overhead = sizeof(struct ipv6hdr);
}
overhead += sizeof(struct sctphdr);
packet->overhead = overhead;
sctp_packet_reset(packet);
packet->vtag = 0;
packet->malloced = 0;
return packet;
}
/* Free a packet. */
void sctp_packet_free(struct sctp_packet *packet)
{
struct sctp_chunk *chunk, *tmp;
SCTP_DEBUG_PRINTK("%s: packet:%p\n", __func__, packet);
list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) {
list_del_init(&chunk->list);
sctp_chunk_free(chunk);
}
if (packet->malloced)
kfree(packet);
}
/* This routine tries to append the chunk to the offered packet. If adding
* the chunk causes the packet to exceed the path MTU and COOKIE_ECHO chunk
* is not present in the packet, it transmits the input packet.
* Data can be bundled with a packet containing a COOKIE_ECHO chunk as long
* as it can fit in the packet, but any more data that does not fit in this
* packet can be sent only after receiving the COOKIE_ACK.
*/
sctp_xmit_t sctp_packet_transmit_chunk(struct sctp_packet *packet,
struct sctp_chunk *chunk,
int one_packet)
{
sctp_xmit_t retval;
int error = 0;
SCTP_DEBUG_PRINTK("%s: packet:%p chunk:%p\n", __func__,
packet, chunk);
switch ((retval = (sctp_packet_append_chunk(packet, chunk)))) {
case SCTP_XMIT_PMTU_FULL:
if (!packet->has_cookie_echo) {
error = sctp_packet_transmit(packet);
if (error < 0)
chunk->skb->sk->sk_err = -error;
/* If we have an empty packet, then we can NOT ever
* return PMTU_FULL.
*/
if (!one_packet)
retval = sctp_packet_append_chunk(packet,
chunk);
}
break;
case SCTP_XMIT_RWND_FULL:
case SCTP_XMIT_OK:
case SCTP_XMIT_NAGLE_DELAY:
break;
}
return retval;
}
/* Try to bundle an auth chunk into the packet. */
static sctp_xmit_t sctp_packet_bundle_auth(struct sctp_packet *pkt,
struct sctp_chunk *chunk)
{
struct sctp_association *asoc = pkt->transport->asoc;
struct sctp_chunk *auth;
sctp_xmit_t retval = SCTP_XMIT_OK;
/* if we don't have an association, we can't do authentication */
if (!asoc)
return retval;
/* See if this is an auth chunk we are bundling or if
* auth is already bundled.
*/
if (chunk->chunk_hdr->type == SCTP_CID_AUTH || pkt->has_auth)
return retval;
/* if the peer did not request this chunk to be authenticated,
* don't do it
*/
if (!chunk->auth)
return retval;
auth = sctp_make_auth(asoc);
if (!auth)
return retval;
retval = __sctp_packet_append_chunk(pkt, auth);
if (retval != SCTP_XMIT_OK)
sctp_chunk_free(auth);
return retval;
}
/* Try to bundle a SACK with the packet. */
static sctp_xmit_t sctp_packet_bundle_sack(struct sctp_packet *pkt,
struct sctp_chunk *chunk)
{
sctp_xmit_t retval = SCTP_XMIT_OK;
/* If sending DATA and haven't aleady bundled a SACK, try to
* bundle one in to the packet.
*/
if (sctp_chunk_is_data(chunk) && !pkt->has_sack &&
!pkt->has_cookie_echo) {
struct sctp_association *asoc;
2009-07-29 16:05:57 +00:00
struct timer_list *timer;
asoc = pkt->transport->asoc;
2009-07-29 16:05:57 +00:00
timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
2009-07-29 16:05:57 +00:00
/* If the SACK timer is running, we have a pending SACK */
if (timer_pending(timer)) {
struct sctp_chunk *sack;
sctp: be more restrictive in transport selection on bundled sacks It was noticed recently that when we send data on a transport, its possible that we might bundle a sack that arrived on a different transport. While this isn't a major problem, it does go against the SHOULD requirement in section 6.4 of RFC 2960: An endpoint SHOULD transmit reply chunks (e.g., SACK, HEARTBEAT ACK, etc.) to the same destination transport address from which it received the DATA or control chunk to which it is replying. This rule should also be followed if the endpoint is bundling DATA chunks together with the reply chunk. This patch seeks to correct that. It restricts the bundling of sack operations to only those transports which have moved the ctsn of the association forward since the last sack. By doing this we guarantee that we only bundle outbound saks on a transport that has received a chunk since the last sack. This brings us into stricter compliance with the RFC. Vlad had initially suggested that we strictly allow only sack bundling on the transport that last moved the ctsn forward. While this makes sense, I was concerned that doing so prevented us from bundling in the case where we had received chunks that moved the ctsn on multiple transports. In those cases, the RFC allows us to select any of the transports having received chunks to bundle the sack on. so I've modified the approach to allow for that, by adding a state variable to each transport that tracks weather it has moved the ctsn since the last sack. This I think keeps our behavior (and performance), close enough to our current profile that I think we can do this without a sysctl knob to enable/disable it. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: Vlad Yaseivch <vyasevich@gmail.com> CC: David S. Miller <davem@davemloft.net> CC: linux-sctp@vger.kernel.org Reported-by: Michele Baldessari <michele@redhat.com> Reported-by: sorin serban <sserban@redhat.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-30 03:04:26 +00:00
if (pkt->transport->sack_generation !=
pkt->transport->asoc->peer.sack_generation)
return retval;
asoc->a_rwnd = asoc->rwnd;
sack = sctp_make_sack(asoc);
if (sack) {
retval = __sctp_packet_append_chunk(pkt, sack);
if (retval != SCTP_XMIT_OK) {
sctp_chunk_free(sack);
goto out;
}
asoc->peer.sack_needed = 0;
2009-07-29 16:05:57 +00:00
if (del_timer(timer))
sctp_association_put(asoc);
}
}
}
out:
return retval;
}
/* Append a chunk to the offered packet reporting back any inability to do
* so.
*/
static sctp_xmit_t __sctp_packet_append_chunk(struct sctp_packet *packet,
struct sctp_chunk *chunk)
{
sctp_xmit_t retval = SCTP_XMIT_OK;
__u16 chunk_len = WORD_ROUND(ntohs(chunk->chunk_hdr->length));
/* Check to see if this chunk will fit into the packet */
retval = sctp_packet_will_fit(packet, chunk, chunk_len);
if (retval != SCTP_XMIT_OK)
goto finish;
/* We believe that this chunk is OK to add to the packet */
switch (chunk->chunk_hdr->type) {
case SCTP_CID_DATA:
/* Account for the data being in the packet */
sctp_packet_append_data(packet, chunk);
/* Disallow SACK bundling after DATA. */
packet->has_sack = 1;
/* Disallow AUTH bundling after DATA */
packet->has_auth = 1;
/* Let it be knows that packet has DATA in it */
packet->has_data = 1;
/* timestamp the chunk for rtx purposes */
chunk->sent_at = jiffies;
break;
case SCTP_CID_COOKIE_ECHO:
packet->has_cookie_echo = 1;
break;
case SCTP_CID_SACK:
packet->has_sack = 1;
break;
case SCTP_CID_AUTH:
packet->has_auth = 1;
packet->auth = chunk;
break;
}
/* It is OK to send this chunk. */
list_add_tail(&chunk->list, &packet->chunk_list);
packet->size += chunk_len;
chunk->transport = packet->transport;
finish:
return retval;
}
/* Append a chunk to the offered packet reporting back any inability to do
* so.
*/
sctp_xmit_t sctp_packet_append_chunk(struct sctp_packet *packet,
struct sctp_chunk *chunk)
{
sctp_xmit_t retval = SCTP_XMIT_OK;
SCTP_DEBUG_PRINTK("%s: packet:%p chunk:%p\n", __func__, packet,
chunk);
/* Data chunks are special. Before seeing what else we can
* bundle into this packet, check to see if we are allowed to
* send this DATA.
*/
if (sctp_chunk_is_data(chunk)) {
retval = sctp_packet_can_append_data(packet, chunk);
if (retval != SCTP_XMIT_OK)
goto finish;
}
/* Try to bundle AUTH chunk */
retval = sctp_packet_bundle_auth(packet, chunk);
if (retval != SCTP_XMIT_OK)
goto finish;
/* Try to bundle SACK chunk */
retval = sctp_packet_bundle_sack(packet, chunk);
if (retval != SCTP_XMIT_OK)
goto finish;
retval = __sctp_packet_append_chunk(packet, chunk);
finish:
return retval;
}
sctp: Don't charge for data in sndbuf again when transmitting packet SCTP charges wmem_alloc via sctp_set_owner_w() in sctp_sendmsg() and via skb_set_owner_w() in sctp_packet_transmit(). If a sender runs out of sndbuf it will sleep in sctp_wait_for_sndbuf() and expects to be waken up by __sctp_write_space(). Buffer space charged via sctp_set_owner_w() is released in sctp_wfree() which calls __sctp_write_space() directly. Buffer space charged via skb_set_owner_w() is released via sock_wfree() which calls sk->sk_write_space() _if_ SOCK_USE_WRITE_QUEUE is not set. sctp_endpoint_init() sets SOCK_USE_WRITE_QUEUE on all sockets. Therefore if sctp_packet_transmit() manages to queue up more than sndbuf bytes, sctp_wait_for_sndbuf() will never be woken up again unless it is interrupted by a signal. This could be fixed by clearing the SOCK_USE_WRITE_QUEUE flag but ... Charging for the data twice does not make sense in the first place, it leads to overcharging sndbuf by a factor 2. Therefore this patch only charges a single byte in wmem_alloc when transmitting an SCTP packet to ensure that the socket stays alive until the packet has been released. This means that control chunks are no longer accounted for in wmem_alloc which I believe is not a problem as skb->truesize will typically lead to overcharging anyway and thus compensates for any control overhead. Signed-off-by: Thomas Graf <tgraf@suug.ch> CC: Vlad Yasevich <vyasevic@redhat.com> CC: Neil Horman <nhorman@tuxdriver.com> CC: David Miller <davem@davemloft.net> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-09-03 04:27:42 +00:00
static void sctp_packet_release_owner(struct sk_buff *skb)
{
sk_free(skb->sk);
}
static void sctp_packet_set_owner_w(struct sk_buff *skb, struct sock *sk)
{
skb_orphan(skb);
skb->sk = sk;
skb->destructor = sctp_packet_release_owner;
/*
* The data chunks have already been accounted for in sctp_sendmsg(),
* therefore only reserve a single byte to keep socket around until
* the packet has been transmitted.
*/
atomic_inc(&sk->sk_wmem_alloc);
}
/* All packets are sent to the network through this function from
* sctp_outq_tail().
*
* The return value is a normal kernel error return value.
*/
int sctp_packet_transmit(struct sctp_packet *packet)
{
struct sctp_transport *tp = packet->transport;
struct sctp_association *asoc = tp->asoc;
struct sctphdr *sh;
struct sk_buff *nskb;
struct sctp_chunk *chunk, *tmp;
struct sock *sk;
int err = 0;
int padding; /* How much padding do we need? */
__u8 has_data = 0;
struct dst_entry *dst = tp->dst;
unsigned char *auth = NULL; /* pointer to auth in skb data */
__u32 cksum_buf_len = sizeof(struct sctphdr);
SCTP_DEBUG_PRINTK("%s: packet:%p\n", __func__, packet);
/* Do NOT generate a chunkless packet. */
if (list_empty(&packet->chunk_list))
return err;
/* Set up convenience variables... */
chunk = list_entry(packet->chunk_list.next, struct sctp_chunk, list);
sk = chunk->skb->sk;
/* Allocate the new skb. */
nskb = alloc_skb(packet->size + LL_MAX_HEADER, GFP_ATOMIC);
if (!nskb)
goto nomem;
/* Make sure the outbound skb has enough header room reserved. */
skb_reserve(nskb, packet->overhead + LL_MAX_HEADER);
/* Set the owning socket so that we know where to get the
* destination IP address.
*/
sctp: Don't charge for data in sndbuf again when transmitting packet SCTP charges wmem_alloc via sctp_set_owner_w() in sctp_sendmsg() and via skb_set_owner_w() in sctp_packet_transmit(). If a sender runs out of sndbuf it will sleep in sctp_wait_for_sndbuf() and expects to be waken up by __sctp_write_space(). Buffer space charged via sctp_set_owner_w() is released in sctp_wfree() which calls __sctp_write_space() directly. Buffer space charged via skb_set_owner_w() is released via sock_wfree() which calls sk->sk_write_space() _if_ SOCK_USE_WRITE_QUEUE is not set. sctp_endpoint_init() sets SOCK_USE_WRITE_QUEUE on all sockets. Therefore if sctp_packet_transmit() manages to queue up more than sndbuf bytes, sctp_wait_for_sndbuf() will never be woken up again unless it is interrupted by a signal. This could be fixed by clearing the SOCK_USE_WRITE_QUEUE flag but ... Charging for the data twice does not make sense in the first place, it leads to overcharging sndbuf by a factor 2. Therefore this patch only charges a single byte in wmem_alloc when transmitting an SCTP packet to ensure that the socket stays alive until the packet has been released. This means that control chunks are no longer accounted for in wmem_alloc which I believe is not a problem as skb->truesize will typically lead to overcharging anyway and thus compensates for any control overhead. Signed-off-by: Thomas Graf <tgraf@suug.ch> CC: Vlad Yasevich <vyasevic@redhat.com> CC: Neil Horman <nhorman@tuxdriver.com> CC: David Miller <davem@davemloft.net> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-09-03 04:27:42 +00:00
sctp_packet_set_owner_w(nskb, sk);
if (!sctp_transport_dst_check(tp)) {
sctp_transport_route(tp, NULL, sctp_sk(sk));
if (asoc && (asoc->param_flags & SPP_PMTUD_ENABLE)) {
sctp_assoc_sync_pmtu(sk, asoc);
}
}
dst = dst_clone(tp->dst);
skb_dst_set(nskb, dst);
if (!dst)
goto no_route;
/* Build the SCTP header. */
sh = (struct sctphdr *)skb_push(nskb, sizeof(struct sctphdr));
skb_reset_transport_header(nskb);
sh->source = htons(packet->source_port);
sh->dest = htons(packet->destination_port);
/* From 6.8 Adler-32 Checksum Calculation:
* After the packet is constructed (containing the SCTP common
* header and one or more control or DATA chunks), the
* transmitter shall:
*
* 1) Fill in the proper Verification Tag in the SCTP common
* header and initialize the checksum field to 0's.
*/
sh->vtag = htonl(packet->vtag);
sh->checksum = 0;
/**
* 6.10 Bundling
*
* An endpoint bundles chunks by simply including multiple
* chunks in one outbound SCTP packet. ...
*/
/**
* 3.2 Chunk Field Descriptions
*
* The total length of a chunk (including Type, Length and
* Value fields) MUST be a multiple of 4 bytes. If the length
* of the chunk is not a multiple of 4 bytes, the sender MUST
* pad the chunk with all zero bytes and this padding is not
* included in the chunk length field. The sender should
* never pad with more than 3 bytes.
*
* [This whole comment explains WORD_ROUND() below.]
*/
SCTP_DEBUG_PRINTK("***sctp_transmit_packet***\n");
list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) {
list_del_init(&chunk->list);
if (sctp_chunk_is_data(chunk)) {
/* 6.3.1 C4) When data is in flight and when allowed
* by rule C5, a new RTT measurement MUST be made each
* round trip. Furthermore, new RTT measurements
* SHOULD be made no more than once per round-trip
* for a given destination transport address.
*/
if (!tp->rto_pending) {
chunk->rtt_in_progress = 1;
tp->rto_pending = 1;
sctp: Fix mis-ordering of user space data when multihoming in use Recently had a bug reported to me, in which the user was sending packets with a payload containing a sequence number. The packets were getting delivered in order according the chunk TSN values, but the sequence values in the payload were arriving out of order. At first I thought it must be an application error, but we eventually found it to be a problem on the transmit side in the sctp stack. The conditions for the error are that multihoming must be in use, and it helps if each transport has a different pmtu. The problem occurs in sctp_outq_flush. Basically we dequeue packets from the data queue, and attempt to append them to the orrered packet for a given transport. After we append a data chunk we add the trasport to the end of a list of transports to have their packets sent at the end of sctp_outq_flush. The problem occurs when a data chunks fills up a offered packet on a transport. The function that does the appending (sctp_packet_transmit_chunk), will try to call sctp_packet_transmit on the full packet, and then append the chunk to a new packet. This call to sctp_packet_transmit, sends that packet ahead of the others that may be queued in the transport_list in sctp_outq_flush. The result is that frames that were sent in one order from the user space sending application get re-ordered prior to tsn assignment in sctp_packet_transmit, resulting in mis-sequencing of data payloads, even though tsn ordering is correct. The fix is to change where we assign a tsn. By doing this earlier, we are then free to place chunks in packets, whatever way we see fit and the protocol will make sure to do all the appropriate re-ordering on receive as is needed. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Reported-by: William Reich <reich@ulticom.com> Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
2009-11-23 20:54:00 +00:00
}
has_data = 1;
}
padding = WORD_ROUND(chunk->skb->len) - chunk->skb->len;
if (padding)
memset(skb_put(chunk->skb, padding), 0, padding);
/* if this is the auth chunk that we are adding,
* store pointer where it will be added and put
* the auth into the packet.
*/
if (chunk == packet->auth)
auth = skb_tail_pointer(nskb);
cksum_buf_len += chunk->skb->len;
memcpy(skb_put(nskb, chunk->skb->len),
chunk->skb->data, chunk->skb->len);
SCTP_DEBUG_PRINTK("%s %p[%s] %s 0x%x, %s %d, %s %d, %s %d\n",
"*** Chunk", chunk,
sctp_cname(SCTP_ST_CHUNK(
chunk->chunk_hdr->type)),
chunk->has_tsn ? "TSN" : "No TSN",
chunk->has_tsn ?
ntohl(chunk->subh.data_hdr->tsn) : 0,
"length", ntohs(chunk->chunk_hdr->length),
"chunk->skb->len", chunk->skb->len,
"rtt_in_progress", chunk->rtt_in_progress);
/*
* If this is a control chunk, this is our last
* reference. Free data chunks after they've been
* acknowledged or have failed.
*/
if (!sctp_chunk_is_data(chunk))
sctp_chunk_free(chunk);
}
/* SCTP-AUTH, Section 6.2
* The sender MUST calculate the MAC as described in RFC2104 [2]
* using the hash function H as described by the MAC Identifier and
* the shared association key K based on the endpoint pair shared key
* described by the shared key identifier. The 'data' used for the
* computation of the AUTH-chunk is given by the AUTH chunk with its
* HMAC field set to zero (as shown in Figure 6) followed by all
* chunks that are placed after the AUTH chunk in the SCTP packet.
*/
if (auth)
sctp_auth_calculate_hmac(asoc, nskb,
(struct sctp_auth_chunk *)auth,
GFP_ATOMIC);
/* 2) Calculate the Adler-32 checksum of the whole packet,
* including the SCTP common header and all the
* chunks.
*
* Note: Adler-32 is no longer applicable, as has been replaced
* by CRC32-C as described in <draft-ietf-tsvwg-sctpcsum-02.txt>.
*/
if (!sctp_checksum_disable) {
if (!(dst->dev->features & NETIF_F_SCTP_CSUM)) {
__u32 crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len);
/* 3) Put the resultant value into the checksum field in the
* common header, and leave the rest of the bits unchanged.
*/
sh->checksum = sctp_end_cksum(crc32);
} else {
/* no need to seed pseudo checksum for SCTP */
nskb->ip_summed = CHECKSUM_PARTIAL;
nskb->csum_start = (skb_transport_header(nskb) -
nskb->head);
nskb->csum_offset = offsetof(struct sctphdr, checksum);
}
}
/* IP layer ECN support
* From RFC 2481
* "The ECN-Capable Transport (ECT) bit would be set by the
* data sender to indicate that the end-points of the
* transport protocol are ECN-capable."
*
* Now setting the ECT bit all the time, as it should not cause
* any problems protocol-wise even if our peer ignores it.
*
* Note: The works for IPv6 layer checks this bit too later
* in transmission. See IP6_ECN_flow_xmit().
*/
(*tp->af_specific->ecn_capable)(nskb->sk);
/* Set up the IP options. */
/* BUG: not implemented
* For v4 this all lives somewhere in sk->sk_opt...
*/
/* Dump that on IP! */
if (asoc && asoc->peer.last_sent_to != tp) {
/* Considering the multiple CPU scenario, this is a
* "correcter" place for last_sent_to. --xguo
*/
asoc->peer.last_sent_to = tp;
}
if (has_data) {
struct timer_list *timer;
unsigned long timeout;
/* Restart the AUTOCLOSE timer when sending data. */
if (sctp_state(asoc, ESTABLISHED) && asoc->autoclose) {
timer = &asoc->timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
timeout = asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
if (!mod_timer(timer, jiffies + timeout))
sctp_association_hold(asoc);
}
}
SCTP_DEBUG_PRINTK("***sctp_transmit_packet*** skb len %d\n",
nskb->len);
nskb->local_df = packet->ipfragok;
(*tp->af_specific->sctp_xmit)(nskb, tp);
out:
sctp_packet_reset(packet);
return err;
no_route:
kfree_skb(nskb);
IP_INC_STATS_BH(sock_net(asoc->base.sk), IPSTATS_MIB_OUTNOROUTES);
/* FIXME: Returning the 'err' will effect all the associations
* associated with a socket, although only one of the paths of the
* association is unreachable.
* The real failure of a transport or association can be passed on
* to the user via notifications. So setting this error may not be
* required.
*/
/* err = -EHOSTUNREACH; */
err:
/* Control chunks are unreliable so just drop them. DATA chunks
* will get resent or dropped later.
*/
list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) {
list_del_init(&chunk->list);
if (!sctp_chunk_is_data(chunk))
sctp_chunk_free(chunk);
}
goto out;
nomem:
err = -ENOMEM;
goto err;
}
/********************************************************************
* 2nd Level Abstractions
********************************************************************/
/* This private function check to see if a chunk can be added */
static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet,
struct sctp_chunk *chunk)
{
sctp_xmit_t retval = SCTP_XMIT_OK;
size_t datasize, rwnd, inflight, flight_size;
struct sctp_transport *transport = packet->transport;
struct sctp_association *asoc = transport->asoc;
struct sctp_outq *q = &asoc->outqueue;
/* RFC 2960 6.1 Transmission of DATA Chunks
*
* A) At any given time, the data sender MUST NOT transmit new data to
* any destination transport address if its peer's rwnd indicates
* that the peer has no buffer space (i.e. rwnd is 0, see Section
* 6.2.1). However, regardless of the value of rwnd (including if it
* is 0), the data sender can always have one DATA chunk in flight to
* the receiver if allowed by cwnd (see rule B below). This rule
* allows the sender to probe for a change in rwnd that the sender
* missed due to the SACK having been lost in transit from the data
* receiver to the data sender.
*/
rwnd = asoc->peer.rwnd;
inflight = q->outstanding_bytes;
flight_size = transport->flight_size;
datasize = sctp_data_size(chunk);
if (datasize > rwnd) {
if (inflight > 0) {
/* We have (at least) one data chunk in flight,
* so we can't fall back to rule 6.1 B).
*/
retval = SCTP_XMIT_RWND_FULL;
goto finish;
}
}
/* RFC 2960 6.1 Transmission of DATA Chunks
*
* B) At any given time, the sender MUST NOT transmit new data
* to a given transport address if it has cwnd or more bytes
* of data outstanding to that transport address.
*/
/* RFC 7.2.4 & the Implementers Guide 2.8.
*
* 3) ...
* When a Fast Retransmit is being performed the sender SHOULD
* ignore the value of cwnd and SHOULD NOT delay retransmission.
*/
if (chunk->fast_retransmit != SCTP_NEED_FRTX)
if (flight_size >= transport->cwnd) {
retval = SCTP_XMIT_RWND_FULL;
goto finish;
}
/* Nagle's algorithm to solve small-packet problem:
* Inhibit the sending of new chunks when new outgoing data arrives
* if any previously transmitted data on the connection remains
* unacknowledged.
*/
if (!sctp_sk(asoc->base.sk)->nodelay && sctp_packet_empty(packet) &&
inflight && sctp_state(asoc, ESTABLISHED)) {
unsigned int max = transport->pathmtu - packet->overhead;
unsigned int len = chunk->skb->len + q->out_qlen;
/* Check whether this chunk and all the rest of pending
* data will fit or delay in hopes of bundling a full
* sized packet.
* Don't delay large message writes that may have been
* fragmeneted into small peices.
*/
if ((len < max) && chunk->msg->can_delay) {
retval = SCTP_XMIT_NAGLE_DELAY;
goto finish;
}
}
finish:
return retval;
}
/* This private function does management things when adding DATA chunk */
static void sctp_packet_append_data(struct sctp_packet *packet,
struct sctp_chunk *chunk)
{
struct sctp_transport *transport = packet->transport;
size_t datasize = sctp_data_size(chunk);
struct sctp_association *asoc = transport->asoc;
u32 rwnd = asoc->peer.rwnd;
/* Keep track of how many bytes are in flight over this transport. */
transport->flight_size += datasize;
/* Keep track of how many bytes are in flight to the receiver. */
asoc->outqueue.outstanding_bytes += datasize;
sctp: Do not account for sizeof(struct sk_buff) in estimated rwnd When checking whether a DATA chunk fits into the estimated rwnd a full sizeof(struct sk_buff) is added to the needed chunk size. This quickly exhausts the available rwnd space and leads to packets being sent which are much below the PMTU limit. This can lead to much worse performance. The reason for this behaviour was to avoid putting too much memory pressure on the receiver. The concept is not completely irational because a Linux receiver does in fact clone an skb for each DATA chunk delivered. However, Linux also reserves half the available socket buffer space for data structures therefore usage of it is already accounted for. When proposing to change this the last time it was noted that this behaviour was introduced to solve a performance issue caused by rwnd overusage in combination with small DATA chunks. Trying to reproduce this I found that with the sk_buff overhead removed, the performance would improve significantly unless socket buffer limits are increased. The following numbers have been gathered using a patched iperf supporting SCTP over a live 1 Gbit ethernet network. The -l option was used to limit DATA chunk sizes. The numbers listed are based on the average of 3 test runs each. Default values have been used for sk_(r|w)mem. Chunk Size Unpatched No Overhead ------------------------------------- 4 15.2 Kbit [!] 12.2 Mbit [!] 8 35.8 Kbit [!] 26.0 Mbit [!] 16 95.5 Kbit [!] 54.4 Mbit [!] 32 106.7 Mbit 102.3 Mbit 64 189.2 Mbit 188.3 Mbit 128 331.2 Mbit 334.8 Mbit 256 537.7 Mbit 536.0 Mbit 512 766.9 Mbit 766.6 Mbit 1024 810.1 Mbit 808.6 Mbit Signed-off-by: Thomas Graf <tgraf@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-19 04:11:40 +00:00
/* Update our view of the receiver's rwnd. */
if (datasize < rwnd)
rwnd -= datasize;
else
rwnd = 0;
asoc->peer.rwnd = rwnd;
/* Has been accepted for transmission. */
if (!asoc->peer.prsctp_capable)
chunk->msg->can_abandon = 0;
sctp: Fix mis-ordering of user space data when multihoming in use Recently had a bug reported to me, in which the user was sending packets with a payload containing a sequence number. The packets were getting delivered in order according the chunk TSN values, but the sequence values in the payload were arriving out of order. At first I thought it must be an application error, but we eventually found it to be a problem on the transmit side in the sctp stack. The conditions for the error are that multihoming must be in use, and it helps if each transport has a different pmtu. The problem occurs in sctp_outq_flush. Basically we dequeue packets from the data queue, and attempt to append them to the orrered packet for a given transport. After we append a data chunk we add the trasport to the end of a list of transports to have their packets sent at the end of sctp_outq_flush. The problem occurs when a data chunks fills up a offered packet on a transport. The function that does the appending (sctp_packet_transmit_chunk), will try to call sctp_packet_transmit on the full packet, and then append the chunk to a new packet. This call to sctp_packet_transmit, sends that packet ahead of the others that may be queued in the transport_list in sctp_outq_flush. The result is that frames that were sent in one order from the user space sending application get re-ordered prior to tsn assignment in sctp_packet_transmit, resulting in mis-sequencing of data payloads, even though tsn ordering is correct. The fix is to change where we assign a tsn. By doing this earlier, we are then free to place chunks in packets, whatever way we see fit and the protocol will make sure to do all the appropriate re-ordering on receive as is needed. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Reported-by: William Reich <reich@ulticom.com> Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
2009-11-23 20:54:00 +00:00
sctp_chunk_assign_tsn(chunk);
sctp_chunk_assign_ssn(chunk);
}
static sctp_xmit_t sctp_packet_will_fit(struct sctp_packet *packet,
struct sctp_chunk *chunk,
u16 chunk_len)
{
size_t psize;
size_t pmtu;
int too_big;
sctp_xmit_t retval = SCTP_XMIT_OK;
psize = packet->size;
pmtu = ((packet->transport->asoc) ?
(packet->transport->asoc->pathmtu) :
(packet->transport->pathmtu));
too_big = (psize + chunk_len > pmtu);
/* Decide if we need to fragment or resubmit later. */
if (too_big) {
/* It's OK to fragmet at IP level if any one of the following
* is true:
* 1. The packet is empty (meaning this chunk is greater
* the MTU)
* 2. The chunk we are adding is a control chunk
* 3. The packet doesn't have any data in it yet and data
* requires authentication.
*/
if (sctp_packet_empty(packet) || !sctp_chunk_is_data(chunk) ||
(!packet->has_data && chunk->auth)) {
/* We no longer do re-fragmentation.
* Just fragment at the IP layer, if we
* actually hit this condition
*/
packet->ipfragok = 1;
} else {
retval = SCTP_XMIT_PMTU_FULL;
}
}
return retval;
}