cregit-Linux how code gets into the kernel

Release 4.11 net/sctp/output.c

Directory: net/sctp
/* 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, see
 * <http://www.gnu.org/licenses/>.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <linux-sctp@vger.kernel.org>
 *
 * 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>
 */


#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 <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; }

Contributors

PersonTokensPropCommitsCommitProp
Jon Grimm2341.82%342.86%
Vladislav Yasevich1629.09%228.57%
Wei Yongjun1018.18%114.29%
Sridhar Samudrala610.91%114.29%
Total55100.00%7100.00%

/* Config a packet. * This appears to be a followup set of initializations. */
void sctp_packet_config(struct sctp_packet *packet, __u32 vtag, int ecn_capable) { struct sctp_transport *tp = packet->transport; struct sctp_association *asoc = tp->asoc; struct sock *sk; pr_debug("%s: packet:%p vtag:0x%x\n", __func__, packet, vtag); packet->vtag = vtag; /* do the following jobs only once for a flush schedule */ if (!sctp_packet_empty(packet)) return; /* set packet max_size with pathmtu */ packet->max_size = tp->pathmtu; if (!asoc) return; /* update dst or transport pathmtu if in need */ sk = asoc->base.sk; if (!sctp_transport_dst_check(tp)) { sctp_transport_route(tp, NULL, sctp_sk(sk)); if (asoc->param_flags & SPP_PMTUD_ENABLE) sctp_assoc_sync_pmtu(asoc); } else if (!sctp_transport_pmtu_check(tp)) { if (asoc->param_flags & SPP_PMTUD_ENABLE) sctp_assoc_sync_pmtu(asoc); } /* If there a is a prepend chunk stick it on the list before * any other chunks get appended. */ if (ecn_capable) { struct sctp_chunk *chunk = sctp_get_ecne_prepend(asoc); if (chunk) sctp_packet_append_chunk(packet, chunk); } if (!tp->dst) return; /* set packet max_size with gso_max_size if gso is enabled*/ rcu_read_lock(); if (__sk_dst_get(sk) != tp->dst) { dst_hold(tp->dst); sk_setup_caps(sk, tp->dst); } packet->max_size = sk_can_gso(sk) ? tp->dst->dev->gso_max_size : asoc->pathmtu; rcu_read_unlock(); }

Contributors

PersonTokensPropCommitsCommitProp
Xin Long13053.72%114.29%
Marcelo Ricardo Leitner5522.73%228.57%
Wei Yongjun3414.05%114.29%
Sridhar Samudrala145.79%114.29%
Jon Grimm83.31%114.29%
Daniel Borkmann10.41%114.29%
Total242100.00%7100.00%

/* Initialize the packet structure. */
void sctp_packet_init(struct sctp_packet *packet, struct sctp_transport *transport, __u16 sport, __u16 dport) { struct sctp_association *asoc = transport->asoc; size_t overhead; pr_debug("%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; }

Contributors

PersonTokensPropCommitsCommitProp
Sridhar Samudrala7555.15%215.38%
Jon Grimm5036.76%430.77%
David S. Miller42.94%215.38%
Wei Yongjun32.21%17.69%
Arnaldo Carvalho de Melo10.74%17.69%
Marcelo Ricardo Leitner10.74%17.69%
Harvey Harrison10.74%17.69%
Daniel Borkmann10.74%17.69%
Total136100.00%13100.00%

/* Free a packet. */
void sctp_packet_free(struct sctp_packet *packet) { struct sctp_chunk *chunk, *tmp; pr_debug("%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); } }

Contributors

PersonTokensPropCommitsCommitProp
Jon Grimm2344.23%337.50%
David S. Miller2038.46%225.00%
Sridhar Samudrala713.46%112.50%
Daniel Borkmann11.92%112.50%
Harvey Harrison11.92%112.50%
Total52100.00%8100.00%

/* 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, gfp_t gfp) { sctp_xmit_t retval; pr_debug("%s: packet:%p size:%zu chunk:%p size:%d\n", __func__, packet, packet->size, chunk, chunk->skb ? chunk->skb->len : -1); switch ((retval = (sctp_packet_append_chunk(packet, chunk)))) { case SCTP_XMIT_PMTU_FULL: if (!packet->has_cookie_echo) { int error = 0; error = sctp_packet_transmit(packet, gfp); 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_DELAY: break; } return retval; }

Contributors

PersonTokensPropCommitsCommitProp
Jon Grimm9063.83%215.38%
Marcelo Ricardo Leitner2215.60%215.38%
Sridhar Samudrala85.67%17.69%
Vladislav Yasevich85.67%17.69%
Xin Long53.55%17.69%
David S. Miller32.13%17.69%
Daniel Borkmann10.71%17.69%
Harvey Harrison10.71%17.69%
David Laight10.71%17.69%
Arnaldo Carvalho de Melo10.71%17.69%
Alexey Dobriyan10.71%17.69%
Total141100.00%13100.00%

/* 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; }

Contributors

PersonTokensPropCommitsCommitProp
Vladislav Yasevich10189.38%266.67%
Neil Horman1210.62%133.33%
Total113100.00%3100.00%

/* 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; struct timer_list *timer; asoc = pkt->transport->asoc; timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK]; /* If the SACK timer is running, we have a pending SACK */ if (timer_pending(timer)) { struct sctp_chunk *sack; 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; if (del_timer(timer)) sctp_association_put(asoc); } } } out: return retval; }

Contributors

PersonTokensPropCommitsCommitProp
Jon Grimm11665.91%125.00%
Neil Horman4022.73%250.00%
Doug Graham2011.36%125.00%
Total176100.00%4100.00%

/* 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 = SCTP_PAD4(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; /* Mainly used for prsctp RTX policy */ chunk->sent_count++; break; case SCTP_CID_COOKIE_ECHO: packet->has_cookie_echo = 1; break; case SCTP_CID_SACK: packet->has_sack = 1; if (chunk->asoc) chunk->asoc->stats.osacks++; 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; }

Contributors

PersonTokensPropCommitsCommitProp
Jon Grimm8743.94%529.41%
Vladislav Yasevich6733.84%317.65%
Michele Baldessari157.58%15.88%
Sridhar Samudrala115.56%317.65%
David S. Miller94.55%211.76%
Xin Long63.03%15.88%
Neil Horman21.01%15.88%
Marcelo Ricardo Leitner10.51%15.88%
Total198100.00%17100.00%

/* 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; pr_debug("%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; }

Contributors

PersonTokensPropCommitsCommitProp
Neil Horman11099.10%150.00%
Daniel Borkmann10.90%150.00%
Total111100.00%2100.00%


static void sctp_packet_release_owner(struct sk_buff *skb) { sk_free(skb->sk); }

Contributors

PersonTokensPropCommitsCommitProp
Thomas Graf18100.00%1100.00%
Total18100.00%1100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
Thomas Graf42100.00%1100.00%
Total42100.00%1100.00%


static int sctp_packet_pack(struct sctp_packet *packet, struct sk_buff *head, int gso, gfp_t gfp) { struct sctp_transport *tp = packet->transport; struct sctp_auth_chunk *auth = NULL; struct sctp_chunk *chunk, *tmp; int pkt_count = 0, pkt_size; struct sock *sk = head->sk; struct sk_buff *nskb; int auth_len = 0; if (gso) { skb_shinfo(head)->gso_type = sk->sk_gso_type; NAPI_GRO_CB(head)->last = head; } else { nskb = head; pkt_size = packet->size; goto merge; } do { /* calculate the pkt_size and alloc nskb */ pkt_size = packet->overhead; list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) { int padded = SCTP_PAD4(chunk->skb->len); if (chunk == packet->auth) auth_len = padded; else if (auth_len + padded + packet->overhead > tp->pathmtu) return 0; else if (pkt_size + padded > tp->pathmtu) break; pkt_size += padded; } nskb = alloc_skb(pkt_size + MAX_HEADER, gfp); if (!nskb) return 0; skb_reserve(nskb, packet->overhead + MAX_HEADER); merge: /* merge chunks into nskb and append nskb into head list */ pkt_size -= packet->overhead; list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) { int padding; list_del_init(&chunk->list); if (sctp_chunk_is_data(chunk)) { if (!sctp_chunk_retransmitted(chunk) && !tp->rto_pending) { chunk->rtt_in_progress = 1; tp->rto_pending = 1; } } padding = SCTP_PAD4(chunk->skb->len) - chunk->skb->len; if (padding) memset(skb_put(chunk->skb, padding), 0, padding); if (chunk == packet->auth) auth = (struct sctp_auth_chunk *) skb_tail_pointer(nskb); memcpy(skb_put(nskb, chunk->skb->len), 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, 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) { if (skb_gro_receive(&head, nskb)) { kfree_skb(nskb); return 0; } if (WARN_ON_ONCE(skb_shinfo(head)->gso_segs >= sk->sk_gso_max_segs)) return 0; } 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_start = skb_transport_header(head) - head->head; head->csum_offset = offsetof(struct sctphdr, checksum); } return pkt_count; }

Contributors

PersonTokensPropCommitsCommitProp
Xin Long54269.94%416.00%
Jon Grimm9712.52%520.00%
Marcelo Ricardo Leitner8110.45%416.00%
Sridhar Samudrala344.39%416.00%
David S. Miller121.55%28.00%
Wang Weidong30.39%14.00%
Nicolas Dichtel20.26%14.00%
Daniel Borkmann20.26%28.00%
Vladislav Yasevich10.13%14.00%
Jesse Brandeburg10.13%14.00%
Total775100.00%25100.00%

/* 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 = (struct sctphdr *)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; }

Contributors

PersonTokensPropCommitsCommitProp
Xin Long30155.84%518.52%
Jon Grimm9417.44%311.11%
Marcelo Ricardo Leitner529.65%27.41%
Julian Anastasov234.27%13.70%
David S. Miller152.78%13.70%
Sridhar Samudrala122.23%414.81%
Vladislav Yasevich101.86%13.70%
Frank Filz101.86%13.70%
Jesse Brandeburg71.30%13.70%
Neil Horman40.74%13.70%
Michele Baldessari30.56%13.70%
Michał Mirosław20.37%13.70%
Herbert Xu20.37%13.70%
Daniel Borkmann10.19%13.70%
Américo Wang10.19%13.70%
Fan Du10.19%13.70%
Lucas Nussbaum10.19%13.70%
Total539100.00%27100.00%

/******************************************************************** * 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) { 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 - sizeof(sctp_data_chunk_t) - 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; }

Contributors

PersonTokensPropCommitsCommitProp
Jon Grimm10146.54%526.32%
David Laight4721.66%210.53%
Vladislav Yasevich3114.29%421.05%
Xin Long125.53%210.53%
Marcelo Ricardo Leitner83.69%15.26%
Sridhar Samudrala83.69%210.53%
Daisy Chang62.76%15.26%
David S. Miller20.92%15.26%
Neil Horman20.92%15.26%
Total217100.00%19100.00%

/* 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;