diff options
author | 2015-08-04 12:17:53 -0700 | |
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committer | 2015-08-04 15:44:42 -0700 | |
commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/net/sctp/output.c | |
parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/net/sctp/output.c')
-rw-r--r-- | kernel/net/sctp/output.c | 788 |
1 files changed, 788 insertions, 0 deletions
diff --git a/kernel/net/sctp/output.c b/kernel/net/sctp/output.c new file mode 100644 index 000000000..abe7c2db2 --- /dev/null +++ b/kernel/net/sctp/output.c @@ -0,0 +1,788 @@ +/* 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; +} + +/* 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; + + pr_debug("%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; + + 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; + + return packet; +} + +/* 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); + } +} + +/* 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; + + pr_debug("%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_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; + 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; +} + + +/* 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; + 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; +} + +/* 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; +} + +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; + unsigned char *auth = NULL; /* pointer to auth in skb data */ + + pr_debug("%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 + MAX_HEADER, GFP_ATOMIC); + if (!nskb) + goto nomem; + + /* Make sure the outbound skb has enough header room reserved. */ + skb_reserve(nskb, packet->overhead + MAX_HEADER); + + /* Set the owning socket so that we know where to get the + * destination IP address. + */ + 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); + if (!dst) + goto no_route; + skb_dst_set(nskb, dst); + + /* 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.] + */ + + pr_debug("***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 (!chunk->resent && !tp->rto_pending) { + chunk->rtt_in_progress = 1; + tp->rto_pending = 1; + } + + 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); + + 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); + + /* + * 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) || + (dst_xfrm(dst) != NULL) || packet->ipfragok) { + sh->checksum = sctp_compute_cksum(nskb, 0); + } 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->stats.opackets++; + if (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->timeouts[SCTP_EVENT_TIMEOUT_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); + } + } + + pr_debug("***sctp_transmit_packet*** skb->len:%d\n", nskb->len); + + nskb->ignore_df = packet->ipfragok; + tp->af_specific->sctp_xmit(nskb, tp); + +out: + sctp_packet_reset(packet); + return err; +no_route: + kfree_skb(nskb); + + if (asoc) + IP_INC_STATS(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) +{ + 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) + /* Nagle disabled */ + return SCTP_XMIT_OK; + + if (!sctp_packet_empty(packet)) + /* Append to packet */ + return SCTP_XMIT_OK; + + if (inflight == 0) + /* Nothing unacked */ + 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) + /* 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; + /* Has been accepted for transmission. */ + if (!asoc->peer.prsctp_capable) + chunk->msg->can_abandon = 0; + 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; +} |