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![Xin Long](/assets/img/avatar_default.png)
Now sctp GSO uses skb_gro_receive() to append the data into head skb frag_list. However it actually only needs very few code from skb_gro_receive(). Besides, NAPI_GRO_CB has to be set while most of its members are not needed here. This patch is to add sctp_packet_gso_append() to build GSO frames instead of skb_gro_receive(), and it would avoid many unnecessary checks and make the code clearer. Note that sctp will use page frags instead of frag_list to build GSO frames in another patch. But it may take time, as sctp's GSO frames may have different size. skb_segment() can only split it into the frags with the same size, which would break the border of sctp chunks. Signed-off-by: Xin Long <lucien.xin@gmail.com> Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
862 lines
24 KiB
C
862 lines
24 KiB
C
/* SCTP kernel implementation
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* (C) Copyright IBM Corp. 2001, 2004
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* Copyright (c) 1999-2000 Cisco, Inc.
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* Copyright (c) 1999-2001 Motorola, Inc.
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*
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* This file is part of the SCTP kernel implementation
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*
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* These functions handle output processing.
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*
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* This SCTP implementation is free software;
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* you can redistribute it and/or modify it under the terms of
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* the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This SCTP implementation is distributed in the hope that it
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* will be useful, but WITHOUT ANY WARRANTY; without even the implied
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* ************************
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* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU CC; see the file COPYING. If not, see
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* <http://www.gnu.org/licenses/>.
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*
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* Please send any bug reports or fixes you make to the
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* email address(es):
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* lksctp developers <linux-sctp@vger.kernel.org>
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*
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* Written or modified by:
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* La Monte H.P. Yarroll <piggy@acm.org>
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* Karl Knutson <karl@athena.chicago.il.us>
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* Jon Grimm <jgrimm@austin.ibm.com>
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* Sridhar Samudrala <sri@us.ibm.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/wait.h>
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#include <linux/time.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <net/inet_ecn.h>
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#include <net/ip.h>
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#include <net/icmp.h>
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#include <net/net_namespace.h>
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#include <linux/socket.h> /* for sa_family_t */
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#include <net/sock.h>
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#include <net/sctp/sctp.h>
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#include <net/sctp/sm.h>
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#include <net/sctp/checksum.h>
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/* Forward declarations for private helpers. */
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static enum sctp_xmit __sctp_packet_append_chunk(struct sctp_packet *packet,
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struct sctp_chunk *chunk);
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static enum sctp_xmit sctp_packet_can_append_data(struct sctp_packet *packet,
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struct sctp_chunk *chunk);
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static void sctp_packet_append_data(struct sctp_packet *packet,
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struct sctp_chunk *chunk);
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static enum sctp_xmit sctp_packet_will_fit(struct sctp_packet *packet,
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struct sctp_chunk *chunk,
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u16 chunk_len);
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static void sctp_packet_reset(struct sctp_packet *packet)
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{
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/* sctp_packet_transmit() relies on this to reset size to the
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* current overhead after sending packets.
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*/
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packet->size = packet->overhead;
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packet->has_cookie_echo = 0;
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packet->has_sack = 0;
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packet->has_data = 0;
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packet->has_auth = 0;
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packet->ipfragok = 0;
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packet->auth = NULL;
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}
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/* Config a packet.
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* This appears to be a followup set of initializations.
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*/
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void sctp_packet_config(struct sctp_packet *packet, __u32 vtag,
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int ecn_capable)
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{
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struct sctp_transport *tp = packet->transport;
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struct sctp_association *asoc = tp->asoc;
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struct sctp_sock *sp = NULL;
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struct sock *sk;
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pr_debug("%s: packet:%p vtag:0x%x\n", __func__, packet, vtag);
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packet->vtag = vtag;
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/* do the following jobs only once for a flush schedule */
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if (!sctp_packet_empty(packet))
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return;
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/* set packet max_size with pathmtu, then calculate overhead */
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packet->max_size = tp->pathmtu;
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if (asoc) {
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sk = asoc->base.sk;
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sp = sctp_sk(sk);
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}
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packet->overhead = sctp_mtu_payload(sp, 0, 0);
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packet->size = packet->overhead;
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if (!asoc)
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return;
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/* update dst or transport pathmtu if in need */
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if (!sctp_transport_dst_check(tp)) {
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sctp_transport_route(tp, NULL, sp);
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if (asoc->param_flags & SPP_PMTUD_ENABLE)
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sctp_assoc_sync_pmtu(asoc);
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}
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/* If there a is a prepend chunk stick it on the list before
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* any other chunks get appended.
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*/
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if (ecn_capable) {
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struct sctp_chunk *chunk = sctp_get_ecne_prepend(asoc);
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if (chunk)
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sctp_packet_append_chunk(packet, chunk);
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}
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if (!tp->dst)
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return;
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/* set packet max_size with gso_max_size if gso is enabled*/
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rcu_read_lock();
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if (__sk_dst_get(sk) != tp->dst) {
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dst_hold(tp->dst);
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sk_setup_caps(sk, tp->dst);
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}
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packet->max_size = sk_can_gso(sk) ? tp->dst->dev->gso_max_size
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: asoc->pathmtu;
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rcu_read_unlock();
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}
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/* Initialize the packet structure. */
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void sctp_packet_init(struct sctp_packet *packet,
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struct sctp_transport *transport,
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__u16 sport, __u16 dport)
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{
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pr_debug("%s: packet:%p transport:%p\n", __func__, packet, transport);
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packet->transport = transport;
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packet->source_port = sport;
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packet->destination_port = dport;
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INIT_LIST_HEAD(&packet->chunk_list);
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/* The overhead will be calculated by sctp_packet_config() */
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packet->overhead = 0;
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sctp_packet_reset(packet);
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packet->vtag = 0;
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}
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/* Free a packet. */
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void sctp_packet_free(struct sctp_packet *packet)
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{
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struct sctp_chunk *chunk, *tmp;
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pr_debug("%s: packet:%p\n", __func__, packet);
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list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) {
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list_del_init(&chunk->list);
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sctp_chunk_free(chunk);
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}
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}
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/* This routine tries to append the chunk to the offered packet. If adding
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* the chunk causes the packet to exceed the path MTU and COOKIE_ECHO chunk
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* is not present in the packet, it transmits the input packet.
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* Data can be bundled with a packet containing a COOKIE_ECHO chunk as long
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* as it can fit in the packet, but any more data that does not fit in this
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* packet can be sent only after receiving the COOKIE_ACK.
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*/
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enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
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struct sctp_chunk *chunk,
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int one_packet, gfp_t gfp)
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{
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enum sctp_xmit retval;
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pr_debug("%s: packet:%p size:%zu chunk:%p size:%d\n", __func__,
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packet, packet->size, chunk, chunk->skb ? chunk->skb->len : -1);
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switch ((retval = (sctp_packet_append_chunk(packet, chunk)))) {
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case SCTP_XMIT_PMTU_FULL:
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if (!packet->has_cookie_echo) {
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int error = 0;
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error = sctp_packet_transmit(packet, gfp);
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if (error < 0)
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chunk->skb->sk->sk_err = -error;
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/* If we have an empty packet, then we can NOT ever
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* return PMTU_FULL.
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*/
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if (!one_packet)
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retval = sctp_packet_append_chunk(packet,
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chunk);
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}
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break;
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case SCTP_XMIT_RWND_FULL:
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case SCTP_XMIT_OK:
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case SCTP_XMIT_DELAY:
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break;
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}
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return retval;
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}
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/* Try to bundle an auth chunk into the packet. */
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static enum sctp_xmit sctp_packet_bundle_auth(struct sctp_packet *pkt,
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struct sctp_chunk *chunk)
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{
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struct sctp_association *asoc = pkt->transport->asoc;
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enum sctp_xmit retval = SCTP_XMIT_OK;
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struct sctp_chunk *auth;
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/* if we don't have an association, we can't do authentication */
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if (!asoc)
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return retval;
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/* See if this is an auth chunk we are bundling or if
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* auth is already bundled.
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*/
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if (chunk->chunk_hdr->type == SCTP_CID_AUTH || pkt->has_auth)
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return retval;
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/* if the peer did not request this chunk to be authenticated,
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* don't do it
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*/
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if (!chunk->auth)
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return retval;
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auth = sctp_make_auth(asoc, chunk->shkey->key_id);
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if (!auth)
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return retval;
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auth->shkey = chunk->shkey;
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sctp_auth_shkey_hold(auth->shkey);
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retval = __sctp_packet_append_chunk(pkt, auth);
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if (retval != SCTP_XMIT_OK)
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sctp_chunk_free(auth);
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return retval;
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}
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/* Try to bundle a SACK with the packet. */
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static enum sctp_xmit sctp_packet_bundle_sack(struct sctp_packet *pkt,
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struct sctp_chunk *chunk)
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{
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enum sctp_xmit retval = SCTP_XMIT_OK;
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/* If sending DATA and haven't aleady bundled a SACK, try to
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* bundle one in to the packet.
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*/
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if (sctp_chunk_is_data(chunk) && !pkt->has_sack &&
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!pkt->has_cookie_echo) {
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struct sctp_association *asoc;
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struct timer_list *timer;
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asoc = pkt->transport->asoc;
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timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
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/* If the SACK timer is running, we have a pending SACK */
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if (timer_pending(timer)) {
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struct sctp_chunk *sack;
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if (pkt->transport->sack_generation !=
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pkt->transport->asoc->peer.sack_generation)
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return retval;
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asoc->a_rwnd = asoc->rwnd;
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sack = sctp_make_sack(asoc);
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if (sack) {
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retval = __sctp_packet_append_chunk(pkt, sack);
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if (retval != SCTP_XMIT_OK) {
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sctp_chunk_free(sack);
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goto out;
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}
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asoc->peer.sack_needed = 0;
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if (del_timer(timer))
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sctp_association_put(asoc);
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}
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}
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}
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out:
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return retval;
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}
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/* Append a chunk to the offered packet reporting back any inability to do
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* so.
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*/
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static enum sctp_xmit __sctp_packet_append_chunk(struct sctp_packet *packet,
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struct sctp_chunk *chunk)
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{
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__u16 chunk_len = SCTP_PAD4(ntohs(chunk->chunk_hdr->length));
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enum sctp_xmit retval = SCTP_XMIT_OK;
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/* Check to see if this chunk will fit into the packet */
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retval = sctp_packet_will_fit(packet, chunk, chunk_len);
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if (retval != SCTP_XMIT_OK)
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goto finish;
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/* We believe that this chunk is OK to add to the packet */
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switch (chunk->chunk_hdr->type) {
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case SCTP_CID_DATA:
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case SCTP_CID_I_DATA:
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/* Account for the data being in the packet */
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sctp_packet_append_data(packet, chunk);
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/* Disallow SACK bundling after DATA. */
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packet->has_sack = 1;
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/* Disallow AUTH bundling after DATA */
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packet->has_auth = 1;
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/* Let it be knows that packet has DATA in it */
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packet->has_data = 1;
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/* timestamp the chunk for rtx purposes */
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chunk->sent_at = jiffies;
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/* Mainly used for prsctp RTX policy */
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chunk->sent_count++;
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break;
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case SCTP_CID_COOKIE_ECHO:
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packet->has_cookie_echo = 1;
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break;
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case SCTP_CID_SACK:
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packet->has_sack = 1;
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if (chunk->asoc)
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chunk->asoc->stats.osacks++;
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break;
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case SCTP_CID_AUTH:
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packet->has_auth = 1;
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packet->auth = chunk;
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break;
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}
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/* It is OK to send this chunk. */
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list_add_tail(&chunk->list, &packet->chunk_list);
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packet->size += chunk_len;
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chunk->transport = packet->transport;
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finish:
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return retval;
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}
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/* Append a chunk to the offered packet reporting back any inability to do
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* so.
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*/
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enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
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struct sctp_chunk *chunk)
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{
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enum sctp_xmit retval = SCTP_XMIT_OK;
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pr_debug("%s: packet:%p chunk:%p\n", __func__, packet, chunk);
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/* Data chunks are special. Before seeing what else we can
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* bundle into this packet, check to see if we are allowed to
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* send this DATA.
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*/
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if (sctp_chunk_is_data(chunk)) {
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retval = sctp_packet_can_append_data(packet, chunk);
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if (retval != SCTP_XMIT_OK)
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goto finish;
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}
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/* Try to bundle AUTH chunk */
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retval = sctp_packet_bundle_auth(packet, chunk);
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if (retval != SCTP_XMIT_OK)
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goto finish;
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/* Try to bundle SACK chunk */
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retval = sctp_packet_bundle_sack(packet, chunk);
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if (retval != SCTP_XMIT_OK)
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goto finish;
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retval = __sctp_packet_append_chunk(packet, chunk);
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finish:
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return retval;
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}
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static void sctp_packet_release_owner(struct sk_buff *skb)
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{
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sk_free(skb->sk);
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}
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static void sctp_packet_set_owner_w(struct sk_buff *skb, struct sock *sk)
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{
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skb_orphan(skb);
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skb->sk = sk;
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skb->destructor = sctp_packet_release_owner;
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/*
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* The data chunks have already been accounted for in sctp_sendmsg(),
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* therefore only reserve a single byte to keep socket around until
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* the packet has been transmitted.
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*/
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refcount_inc(&sk->sk_wmem_alloc);
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}
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static void sctp_packet_gso_append(struct sk_buff *head, struct sk_buff *skb)
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{
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if (SCTP_OUTPUT_CB(head)->last == head)
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skb_shinfo(head)->frag_list = skb;
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else
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SCTP_OUTPUT_CB(head)->last->next = skb;
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SCTP_OUTPUT_CB(head)->last = skb;
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head->truesize += skb->truesize;
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head->data_len += skb->len;
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head->len += skb->len;
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__skb_header_release(skb);
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}
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static int sctp_packet_pack(struct sctp_packet *packet,
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struct sk_buff *head, int gso, gfp_t gfp)
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{
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struct sctp_transport *tp = packet->transport;
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struct sctp_auth_chunk *auth = NULL;
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struct sctp_chunk *chunk, *tmp;
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int pkt_count = 0, pkt_size;
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struct sock *sk = head->sk;
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struct sk_buff *nskb;
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int auth_len = 0;
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if (gso) {
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skb_shinfo(head)->gso_type = sk->sk_gso_type;
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SCTP_OUTPUT_CB(head)->last = head;
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} else {
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nskb = head;
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pkt_size = packet->size;
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goto merge;
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}
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do {
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/* calculate the pkt_size and alloc nskb */
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pkt_size = packet->overhead;
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list_for_each_entry_safe(chunk, tmp, &packet->chunk_list,
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list) {
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int padded = SCTP_PAD4(chunk->skb->len);
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if (chunk == packet->auth)
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auth_len = padded;
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else if (auth_len + padded + packet->overhead >
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tp->pathmtu)
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return 0;
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else if (pkt_size + padded > tp->pathmtu)
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break;
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pkt_size += padded;
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}
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nskb = alloc_skb(pkt_size + MAX_HEADER, gfp);
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if (!nskb)
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return 0;
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skb_reserve(nskb, packet->overhead + MAX_HEADER);
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merge:
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/* merge chunks into nskb and append nskb into head list */
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pkt_size -= packet->overhead;
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list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) {
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int padding;
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list_del_init(&chunk->list);
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if (sctp_chunk_is_data(chunk)) {
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if (!sctp_chunk_retransmitted(chunk) &&
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!tp->rto_pending) {
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chunk->rtt_in_progress = 1;
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tp->rto_pending = 1;
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}
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}
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|
|
padding = SCTP_PAD4(chunk->skb->len) - chunk->skb->len;
|
|
if (padding)
|
|
skb_put_zero(chunk->skb, padding);
|
|
|
|
if (chunk == packet->auth)
|
|
auth = (struct sctp_auth_chunk *)
|
|
skb_tail_pointer(nskb);
|
|
|
|
skb_put_data(nskb, chunk->skb->data, chunk->skb->len);
|
|
|
|
pr_debug("*** Chunk:%p[%s] %s 0x%x, length:%d, chunk->skb->len:%d, rtt_in_progress:%d\n",
|
|
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,
|
|
ntohs(chunk->chunk_hdr->length), chunk->skb->len,
|
|
chunk->rtt_in_progress);
|
|
|
|
pkt_size -= SCTP_PAD4(chunk->skb->len);
|
|
|
|
if (!sctp_chunk_is_data(chunk) && chunk != packet->auth)
|
|
sctp_chunk_free(chunk);
|
|
|
|
if (!pkt_size)
|
|
break;
|
|
}
|
|
|
|
if (auth) {
|
|
sctp_auth_calculate_hmac(tp->asoc, nskb, auth,
|
|
packet->auth->shkey, gfp);
|
|
/* free auth if no more chunks, or add it back */
|
|
if (list_empty(&packet->chunk_list))
|
|
sctp_chunk_free(packet->auth);
|
|
else
|
|
list_add(&packet->auth->list,
|
|
&packet->chunk_list);
|
|
}
|
|
|
|
if (gso)
|
|
sctp_packet_gso_append(head, nskb);
|
|
|
|
pkt_count++;
|
|
} while (!list_empty(&packet->chunk_list));
|
|
|
|
if (gso) {
|
|
memset(head->cb, 0, max(sizeof(struct inet_skb_parm),
|
|
sizeof(struct inet6_skb_parm)));
|
|
skb_shinfo(head)->gso_segs = pkt_count;
|
|
skb_shinfo(head)->gso_size = GSO_BY_FRAGS;
|
|
rcu_read_lock();
|
|
if (skb_dst(head) != tp->dst) {
|
|
dst_hold(tp->dst);
|
|
sk_setup_caps(sk, tp->dst);
|
|
}
|
|
rcu_read_unlock();
|
|
goto chksum;
|
|
}
|
|
|
|
if (sctp_checksum_disable)
|
|
return 1;
|
|
|
|
if (!(skb_dst(head)->dev->features & NETIF_F_SCTP_CRC) ||
|
|
dst_xfrm(skb_dst(head)) || packet->ipfragok) {
|
|
struct sctphdr *sh =
|
|
(struct sctphdr *)skb_transport_header(head);
|
|
|
|
sh->checksum = sctp_compute_cksum(head, 0);
|
|
} else {
|
|
chksum:
|
|
head->ip_summed = CHECKSUM_PARTIAL;
|
|
head->csum_not_inet = 1;
|
|
head->csum_start = skb_transport_header(head) - head->head;
|
|
head->csum_offset = offsetof(struct sctphdr, checksum);
|
|
}
|
|
|
|
return pkt_count;
|
|
}
|
|
|
|
/* All packets are sent to the network through this function from
|
|
* sctp_outq_tail().
|
|
*
|
|
* The return value is always 0 for now.
|
|
*/
|
|
int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp)
|
|
{
|
|
struct sctp_transport *tp = packet->transport;
|
|
struct sctp_association *asoc = tp->asoc;
|
|
struct sctp_chunk *chunk, *tmp;
|
|
int pkt_count, gso = 0;
|
|
struct dst_entry *dst;
|
|
struct sk_buff *head;
|
|
struct sctphdr *sh;
|
|
struct sock *sk;
|
|
|
|
pr_debug("%s: packet:%p\n", __func__, packet);
|
|
if (list_empty(&packet->chunk_list))
|
|
return 0;
|
|
chunk = list_entry(packet->chunk_list.next, struct sctp_chunk, list);
|
|
sk = chunk->skb->sk;
|
|
|
|
/* check gso */
|
|
if (packet->size > tp->pathmtu && !packet->ipfragok) {
|
|
if (!sk_can_gso(sk)) {
|
|
pr_err_once("Trying to GSO but underlying device doesn't support it.");
|
|
goto out;
|
|
}
|
|
gso = 1;
|
|
}
|
|
|
|
/* alloc head skb */
|
|
head = alloc_skb((gso ? packet->overhead : packet->size) +
|
|
MAX_HEADER, gfp);
|
|
if (!head)
|
|
goto out;
|
|
skb_reserve(head, packet->overhead + MAX_HEADER);
|
|
sctp_packet_set_owner_w(head, sk);
|
|
|
|
/* set sctp header */
|
|
sh = skb_push(head, sizeof(struct sctphdr));
|
|
skb_reset_transport_header(head);
|
|
sh->source = htons(packet->source_port);
|
|
sh->dest = htons(packet->destination_port);
|
|
sh->vtag = htonl(packet->vtag);
|
|
sh->checksum = 0;
|
|
|
|
/* drop packet if no dst */
|
|
dst = dst_clone(tp->dst);
|
|
if (!dst) {
|
|
IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
|
|
kfree_skb(head);
|
|
goto out;
|
|
}
|
|
skb_dst_set(head, dst);
|
|
|
|
/* pack up chunks */
|
|
pkt_count = sctp_packet_pack(packet, head, gso, gfp);
|
|
if (!pkt_count) {
|
|
kfree_skb(head);
|
|
goto out;
|
|
}
|
|
pr_debug("***sctp_transmit_packet*** skb->len:%d\n", head->len);
|
|
|
|
/* start autoclose timer */
|
|
if (packet->has_data && sctp_state(asoc, ESTABLISHED) &&
|
|
asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
|
|
struct timer_list *timer =
|
|
&asoc->timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
|
|
unsigned long timeout =
|
|
asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
|
|
|
|
if (!mod_timer(timer, jiffies + timeout))
|
|
sctp_association_hold(asoc);
|
|
}
|
|
|
|
/* sctp xmit */
|
|
tp->af_specific->ecn_capable(sk);
|
|
if (asoc) {
|
|
asoc->stats.opackets += pkt_count;
|
|
if (asoc->peer.last_sent_to != tp)
|
|
asoc->peer.last_sent_to = tp;
|
|
}
|
|
head->ignore_df = packet->ipfragok;
|
|
if (tp->dst_pending_confirm)
|
|
skb_set_dst_pending_confirm(head, 1);
|
|
/* neighbour should be confirmed on successful transmission or
|
|
* positive error
|
|
*/
|
|
if (tp->af_specific->sctp_xmit(head, tp) >= 0 &&
|
|
tp->dst_pending_confirm)
|
|
tp->dst_pending_confirm = 0;
|
|
|
|
out:
|
|
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);
|
|
}
|
|
sctp_packet_reset(packet);
|
|
return 0;
|
|
}
|
|
|
|
/********************************************************************
|
|
* 2nd Level Abstractions
|
|
********************************************************************/
|
|
|
|
/* This private function check to see if a chunk can be added */
|
|
static enum sctp_xmit sctp_packet_can_append_data(struct sctp_packet *packet,
|
|
struct sctp_chunk *chunk)
|
|
{
|
|
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 && inflight > 0)
|
|
/* We have (at least) one data chunk in flight,
|
|
* so we can't fall back to rule 6.1 B).
|
|
*/
|
|
return SCTP_XMIT_RWND_FULL;
|
|
|
|
/* 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 &&
|
|
flight_size >= transport->cwnd)
|
|
return SCTP_XMIT_RWND_FULL;
|
|
|
|
/* 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 || inflight == 0) &&
|
|
!asoc->force_delay)
|
|
/* Nothing unacked */
|
|
return SCTP_XMIT_OK;
|
|
|
|
if (!sctp_packet_empty(packet))
|
|
/* Append to packet */
|
|
return SCTP_XMIT_OK;
|
|
|
|
if (!sctp_state(asoc, ESTABLISHED))
|
|
return SCTP_XMIT_OK;
|
|
|
|
/* Check whether this chunk and all the rest of pending data will fit
|
|
* or delay in hopes of bundling a full sized packet.
|
|
*/
|
|
if (chunk->skb->len + q->out_qlen > transport->pathmtu -
|
|
packet->overhead - sctp_datachk_len(&chunk->asoc->stream) - 4)
|
|
/* Enough data queued to fill a packet */
|
|
return SCTP_XMIT_OK;
|
|
|
|
/* Don't delay large message writes that may have been fragmented */
|
|
if (!chunk->msg->can_delay)
|
|
return SCTP_XMIT_OK;
|
|
|
|
/* Defer until all data acked or packet full */
|
|
return SCTP_XMIT_DELAY;
|
|
}
|
|
|
|
/* 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;
|
|
|
|
/* Update our view of the receiver's rwnd. */
|
|
if (datasize < rwnd)
|
|
rwnd -= datasize;
|
|
else
|
|
rwnd = 0;
|
|
|
|
asoc->peer.rwnd = rwnd;
|
|
sctp_chunk_assign_tsn(chunk);
|
|
asoc->stream.si->assign_number(chunk);
|
|
}
|
|
|
|
static enum sctp_xmit sctp_packet_will_fit(struct sctp_packet *packet,
|
|
struct sctp_chunk *chunk,
|
|
u16 chunk_len)
|
|
{
|
|
enum sctp_xmit retval = SCTP_XMIT_OK;
|
|
size_t psize, pmtu, maxsize;
|
|
|
|
/* Don't bundle in this packet if this chunk's auth key doesn't
|
|
* match other chunks already enqueued on this packet. Also,
|
|
* don't bundle the chunk with auth key if other chunks in this
|
|
* packet don't have auth key.
|
|
*/
|
|
if ((packet->auth && chunk->shkey != packet->auth->shkey) ||
|
|
(!packet->auth && chunk->shkey &&
|
|
chunk->chunk_hdr->type != SCTP_CID_AUTH))
|
|
return SCTP_XMIT_PMTU_FULL;
|
|
|
|
psize = packet->size;
|
|
if (packet->transport->asoc)
|
|
pmtu = packet->transport->asoc->pathmtu;
|
|
else
|
|
pmtu = packet->transport->pathmtu;
|
|
|
|
/* Decide if we need to fragment or resubmit later. */
|
|
if (psize + chunk_len > pmtu) {
|
|
/* It's OK to fragment 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 packet doesn't have any data in it yet and data
|
|
* requires authentication.
|
|
*/
|
|
if (sctp_packet_empty(packet) ||
|
|
(!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;
|
|
goto out;
|
|
}
|
|
|
|
/* Similarly, if this chunk was built before a PMTU
|
|
* reduction, we have to fragment it at IP level now. So
|
|
* if the packet already contains something, we need to
|
|
* flush.
|
|
*/
|
|
maxsize = pmtu - packet->overhead;
|
|
if (packet->auth)
|
|
maxsize -= SCTP_PAD4(packet->auth->skb->len);
|
|
if (chunk_len > maxsize)
|
|
retval = SCTP_XMIT_PMTU_FULL;
|
|
|
|
/* It is also okay to fragment if the chunk we are
|
|
* adding is a control chunk, but only if current packet
|
|
* is not a GSO one otherwise it causes fragmentation of
|
|
* a large frame. So in this case we allow the
|
|
* fragmentation by forcing it to be in a new packet.
|
|
*/
|
|
if (!sctp_chunk_is_data(chunk) && packet->has_data)
|
|
retval = SCTP_XMIT_PMTU_FULL;
|
|
|
|
if (psize + chunk_len > packet->max_size)
|
|
/* Hit GSO/PMTU limit, gotta flush */
|
|
retval = SCTP_XMIT_PMTU_FULL;
|
|
|
|
if (!packet->transport->burst_limited &&
|
|
psize + chunk_len > (packet->transport->cwnd >> 1))
|
|
/* Do not allow a single GSO packet to use more
|
|
* than half of cwnd.
|
|
*/
|
|
retval = SCTP_XMIT_PMTU_FULL;
|
|
|
|
if (packet->transport->burst_limited &&
|
|
psize + chunk_len > (packet->transport->burst_limited >> 1))
|
|
/* Do not allow a single GSO packet to use more
|
|
* than half of original cwnd.
|
|
*/
|
|
retval = SCTP_XMIT_PMTU_FULL;
|
|
/* Otherwise it will fit in the GSO packet */
|
|
}
|
|
|
|
out:
|
|
return retval;
|
|
}
|