v4.19.13 snapshot.
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
new file mode 100644
index 0000000..7bb8e56
--- /dev/null
+++ b/net/sctp/outqueue.c
@@ -0,0 +1,1908 @@
+/* SCTP kernel implementation
+ * (C) Copyright IBM Corp. 2001, 2004
+ * Copyright (c) 1999-2000 Cisco, Inc.
+ * Copyright (c) 1999-2001 Motorola, Inc.
+ * Copyright (c) 2001-2003 Intel Corp.
+ *
+ * This file is part of the SCTP kernel implementation
+ *
+ * These functions implement the sctp_outq class. The outqueue handles
+ * bundling and queueing of outgoing SCTP chunks.
+ *
+ * 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>
+ * Perry Melange <pmelange@null.cc.uic.edu>
+ * Xingang Guo <xingang.guo@intel.com>
+ * Hui Huang <hui.huang@nokia.com>
+ * Sridhar Samudrala <sri@us.ibm.com>
+ * Jon Grimm <jgrimm@us.ibm.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/list.h> /* For struct list_head */
+#include <linux/socket.h>
+#include <linux/ip.h>
+#include <linux/slab.h>
+#include <net/sock.h> /* For skb_set_owner_w */
+
+#include <net/sctp/sctp.h>
+#include <net/sctp/sm.h>
+#include <net/sctp/stream_sched.h>
+
+/* Declare internal functions here. */
+static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn);
+static void sctp_check_transmitted(struct sctp_outq *q,
+ struct list_head *transmitted_queue,
+ struct sctp_transport *transport,
+ union sctp_addr *saddr,
+ struct sctp_sackhdr *sack,
+ __u32 *highest_new_tsn);
+
+static void sctp_mark_missing(struct sctp_outq *q,
+ struct list_head *transmitted_queue,
+ struct sctp_transport *transport,
+ __u32 highest_new_tsn,
+ int count_of_newacks);
+
+static void sctp_outq_flush(struct sctp_outq *q, int rtx_timeout, gfp_t gfp);
+
+/* Add data to the front of the queue. */
+static inline void sctp_outq_head_data(struct sctp_outq *q,
+ struct sctp_chunk *ch)
+{
+ struct sctp_stream_out_ext *oute;
+ __u16 stream;
+
+ list_add(&ch->list, &q->out_chunk_list);
+ q->out_qlen += ch->skb->len;
+
+ stream = sctp_chunk_stream_no(ch);
+ oute = SCTP_SO(&q->asoc->stream, stream)->ext;
+ list_add(&ch->stream_list, &oute->outq);
+}
+
+/* Take data from the front of the queue. */
+static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q)
+{
+ return q->sched->dequeue(q);
+}
+
+/* Add data chunk to the end of the queue. */
+static inline void sctp_outq_tail_data(struct sctp_outq *q,
+ struct sctp_chunk *ch)
+{
+ struct sctp_stream_out_ext *oute;
+ __u16 stream;
+
+ list_add_tail(&ch->list, &q->out_chunk_list);
+ q->out_qlen += ch->skb->len;
+
+ stream = sctp_chunk_stream_no(ch);
+ oute = SCTP_SO(&q->asoc->stream, stream)->ext;
+ list_add_tail(&ch->stream_list, &oute->outq);
+}
+
+/*
+ * SFR-CACC algorithm:
+ * D) If count_of_newacks is greater than or equal to 2
+ * and t was not sent to the current primary then the
+ * sender MUST NOT increment missing report count for t.
+ */
+static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary,
+ struct sctp_transport *transport,
+ int count_of_newacks)
+{
+ if (count_of_newacks >= 2 && transport != primary)
+ return 1;
+ return 0;
+}
+
+/*
+ * SFR-CACC algorithm:
+ * F) If count_of_newacks is less than 2, let d be the
+ * destination to which t was sent. If cacc_saw_newack
+ * is 0 for destination d, then the sender MUST NOT
+ * increment missing report count for t.
+ */
+static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport,
+ int count_of_newacks)
+{
+ if (count_of_newacks < 2 &&
+ (transport && !transport->cacc.cacc_saw_newack))
+ return 1;
+ return 0;
+}
+
+/*
+ * SFR-CACC algorithm:
+ * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD
+ * execute steps C, D, F.
+ *
+ * C has been implemented in sctp_outq_sack
+ */
+static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary,
+ struct sctp_transport *transport,
+ int count_of_newacks)
+{
+ if (!primary->cacc.cycling_changeover) {
+ if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks))
+ return 1;
+ if (sctp_cacc_skip_3_1_f(transport, count_of_newacks))
+ return 1;
+ return 0;
+ }
+ return 0;
+}
+
+/*
+ * SFR-CACC algorithm:
+ * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less
+ * than next_tsn_at_change of the current primary, then
+ * the sender MUST NOT increment missing report count
+ * for t.
+ */
+static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn)
+{
+ if (primary->cacc.cycling_changeover &&
+ TSN_lt(tsn, primary->cacc.next_tsn_at_change))
+ return 1;
+ return 0;
+}
+
+/*
+ * SFR-CACC algorithm:
+ * 3) If the missing report count for TSN t is to be
+ * incremented according to [RFC2960] and
+ * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set,
+ * then the sender MUST further execute steps 3.1 and
+ * 3.2 to determine if the missing report count for
+ * TSN t SHOULD NOT be incremented.
+ *
+ * 3.3) If 3.1 and 3.2 do not dictate that the missing
+ * report count for t should not be incremented, then
+ * the sender SHOULD increment missing report count for
+ * t (according to [RFC2960] and [SCTP_STEWART_2002]).
+ */
+static inline int sctp_cacc_skip(struct sctp_transport *primary,
+ struct sctp_transport *transport,
+ int count_of_newacks,
+ __u32 tsn)
+{
+ if (primary->cacc.changeover_active &&
+ (sctp_cacc_skip_3_1(primary, transport, count_of_newacks) ||
+ sctp_cacc_skip_3_2(primary, tsn)))
+ return 1;
+ return 0;
+}
+
+/* Initialize an existing sctp_outq. This does the boring stuff.
+ * You still need to define handlers if you really want to DO
+ * something with this structure...
+ */
+void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q)
+{
+ memset(q, 0, sizeof(struct sctp_outq));
+
+ q->asoc = asoc;
+ INIT_LIST_HEAD(&q->out_chunk_list);
+ INIT_LIST_HEAD(&q->control_chunk_list);
+ INIT_LIST_HEAD(&q->retransmit);
+ INIT_LIST_HEAD(&q->sacked);
+ INIT_LIST_HEAD(&q->abandoned);
+ sctp_sched_set_sched(asoc, SCTP_SS_DEFAULT);
+}
+
+/* Free the outqueue structure and any related pending chunks.
+ */
+static void __sctp_outq_teardown(struct sctp_outq *q)
+{
+ struct sctp_transport *transport;
+ struct list_head *lchunk, *temp;
+ struct sctp_chunk *chunk, *tmp;
+
+ /* Throw away unacknowledged chunks. */
+ list_for_each_entry(transport, &q->asoc->peer.transport_addr_list,
+ transports) {
+ while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) {
+ chunk = list_entry(lchunk, struct sctp_chunk,
+ transmitted_list);
+ /* Mark as part of a failed message. */
+ sctp_chunk_fail(chunk, q->error);
+ sctp_chunk_free(chunk);
+ }
+ }
+
+ /* Throw away chunks that have been gap ACKed. */
+ list_for_each_safe(lchunk, temp, &q->sacked) {
+ list_del_init(lchunk);
+ chunk = list_entry(lchunk, struct sctp_chunk,
+ transmitted_list);
+ sctp_chunk_fail(chunk, q->error);
+ sctp_chunk_free(chunk);
+ }
+
+ /* Throw away any chunks in the retransmit queue. */
+ list_for_each_safe(lchunk, temp, &q->retransmit) {
+ list_del_init(lchunk);
+ chunk = list_entry(lchunk, struct sctp_chunk,
+ transmitted_list);
+ sctp_chunk_fail(chunk, q->error);
+ sctp_chunk_free(chunk);
+ }
+
+ /* Throw away any chunks that are in the abandoned queue. */
+ list_for_each_safe(lchunk, temp, &q->abandoned) {
+ list_del_init(lchunk);
+ chunk = list_entry(lchunk, struct sctp_chunk,
+ transmitted_list);
+ sctp_chunk_fail(chunk, q->error);
+ sctp_chunk_free(chunk);
+ }
+
+ /* Throw away any leftover data chunks. */
+ while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
+ sctp_sched_dequeue_done(q, chunk);
+
+ /* Mark as send failure. */
+ sctp_chunk_fail(chunk, q->error);
+ sctp_chunk_free(chunk);
+ }
+
+ /* Throw away any leftover control chunks. */
+ list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
+ list_del_init(&chunk->list);
+ sctp_chunk_free(chunk);
+ }
+}
+
+void sctp_outq_teardown(struct sctp_outq *q)
+{
+ __sctp_outq_teardown(q);
+ sctp_outq_init(q->asoc, q);
+}
+
+/* Free the outqueue structure and any related pending chunks. */
+void sctp_outq_free(struct sctp_outq *q)
+{
+ /* Throw away leftover chunks. */
+ __sctp_outq_teardown(q);
+}
+
+/* Put a new chunk in an sctp_outq. */
+void sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk, gfp_t gfp)
+{
+ struct net *net = sock_net(q->asoc->base.sk);
+
+ pr_debug("%s: outq:%p, chunk:%p[%s]\n", __func__, q, chunk,
+ chunk && chunk->chunk_hdr ?
+ sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) :
+ "illegal chunk");
+
+ /* If it is data, queue it up, otherwise, send it
+ * immediately.
+ */
+ if (sctp_chunk_is_data(chunk)) {
+ pr_debug("%s: outqueueing: outq:%p, chunk:%p[%s])\n",
+ __func__, q, chunk, chunk && chunk->chunk_hdr ?
+ sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) :
+ "illegal chunk");
+
+ sctp_outq_tail_data(q, chunk);
+ if (chunk->asoc->peer.prsctp_capable &&
+ SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))
+ chunk->asoc->sent_cnt_removable++;
+ if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
+ SCTP_INC_STATS(net, SCTP_MIB_OUTUNORDERCHUNKS);
+ else
+ SCTP_INC_STATS(net, SCTP_MIB_OUTORDERCHUNKS);
+ } else {
+ list_add_tail(&chunk->list, &q->control_chunk_list);
+ SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
+ }
+
+ if (!q->cork)
+ sctp_outq_flush(q, 0, gfp);
+}
+
+/* Insert a chunk into the sorted list based on the TSNs. The retransmit list
+ * and the abandoned list are in ascending order.
+ */
+static void sctp_insert_list(struct list_head *head, struct list_head *new)
+{
+ struct list_head *pos;
+ struct sctp_chunk *nchunk, *lchunk;
+ __u32 ntsn, ltsn;
+ int done = 0;
+
+ nchunk = list_entry(new, struct sctp_chunk, transmitted_list);
+ ntsn = ntohl(nchunk->subh.data_hdr->tsn);
+
+ list_for_each(pos, head) {
+ lchunk = list_entry(pos, struct sctp_chunk, transmitted_list);
+ ltsn = ntohl(lchunk->subh.data_hdr->tsn);
+ if (TSN_lt(ntsn, ltsn)) {
+ list_add(new, pos->prev);
+ done = 1;
+ break;
+ }
+ }
+ if (!done)
+ list_add_tail(new, head);
+}
+
+static int sctp_prsctp_prune_sent(struct sctp_association *asoc,
+ struct sctp_sndrcvinfo *sinfo,
+ struct list_head *queue, int msg_len)
+{
+ struct sctp_chunk *chk, *temp;
+
+ list_for_each_entry_safe(chk, temp, queue, transmitted_list) {
+ struct sctp_stream_out *streamout;
+
+ if (!chk->msg->abandoned &&
+ (!SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) ||
+ chk->sinfo.sinfo_timetolive <= sinfo->sinfo_timetolive))
+ continue;
+
+ chk->msg->abandoned = 1;
+ list_del_init(&chk->transmitted_list);
+ sctp_insert_list(&asoc->outqueue.abandoned,
+ &chk->transmitted_list);
+
+ streamout = SCTP_SO(&asoc->stream, chk->sinfo.sinfo_stream);
+ asoc->sent_cnt_removable--;
+ asoc->abandoned_sent[SCTP_PR_INDEX(PRIO)]++;
+ streamout->ext->abandoned_sent[SCTP_PR_INDEX(PRIO)]++;
+
+ if (queue != &asoc->outqueue.retransmit &&
+ !chk->tsn_gap_acked) {
+ if (chk->transport)
+ chk->transport->flight_size -=
+ sctp_data_size(chk);
+ asoc->outqueue.outstanding_bytes -= sctp_data_size(chk);
+ }
+
+ msg_len -= SCTP_DATA_SNDSIZE(chk) +
+ sizeof(struct sk_buff) +
+ sizeof(struct sctp_chunk);
+ if (msg_len <= 0)
+ break;
+ }
+
+ return msg_len;
+}
+
+static int sctp_prsctp_prune_unsent(struct sctp_association *asoc,
+ struct sctp_sndrcvinfo *sinfo, int msg_len)
+{
+ struct sctp_outq *q = &asoc->outqueue;
+ struct sctp_chunk *chk, *temp;
+
+ q->sched->unsched_all(&asoc->stream);
+
+ list_for_each_entry_safe(chk, temp, &q->out_chunk_list, list) {
+ if (!chk->msg->abandoned &&
+ (!(chk->chunk_hdr->flags & SCTP_DATA_FIRST_FRAG) ||
+ !SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) ||
+ chk->sinfo.sinfo_timetolive <= sinfo->sinfo_timetolive))
+ continue;
+
+ chk->msg->abandoned = 1;
+ sctp_sched_dequeue_common(q, chk);
+ asoc->sent_cnt_removable--;
+ asoc->abandoned_unsent[SCTP_PR_INDEX(PRIO)]++;
+ if (chk->sinfo.sinfo_stream < asoc->stream.outcnt) {
+ struct sctp_stream_out *streamout =
+ SCTP_SO(&asoc->stream, chk->sinfo.sinfo_stream);
+
+ streamout->ext->abandoned_unsent[SCTP_PR_INDEX(PRIO)]++;
+ }
+
+ msg_len -= SCTP_DATA_SNDSIZE(chk) +
+ sizeof(struct sk_buff) +
+ sizeof(struct sctp_chunk);
+ sctp_chunk_free(chk);
+ if (msg_len <= 0)
+ break;
+ }
+
+ q->sched->sched_all(&asoc->stream);
+
+ return msg_len;
+}
+
+/* Abandon the chunks according their priorities */
+void sctp_prsctp_prune(struct sctp_association *asoc,
+ struct sctp_sndrcvinfo *sinfo, int msg_len)
+{
+ struct sctp_transport *transport;
+
+ if (!asoc->peer.prsctp_capable || !asoc->sent_cnt_removable)
+ return;
+
+ msg_len = sctp_prsctp_prune_sent(asoc, sinfo,
+ &asoc->outqueue.retransmit,
+ msg_len);
+ if (msg_len <= 0)
+ return;
+
+ list_for_each_entry(transport, &asoc->peer.transport_addr_list,
+ transports) {
+ msg_len = sctp_prsctp_prune_sent(asoc, sinfo,
+ &transport->transmitted,
+ msg_len);
+ if (msg_len <= 0)
+ return;
+ }
+
+ sctp_prsctp_prune_unsent(asoc, sinfo, msg_len);
+}
+
+/* Mark all the eligible packets on a transport for retransmission. */
+void sctp_retransmit_mark(struct sctp_outq *q,
+ struct sctp_transport *transport,
+ __u8 reason)
+{
+ struct list_head *lchunk, *ltemp;
+ struct sctp_chunk *chunk;
+
+ /* Walk through the specified transmitted queue. */
+ list_for_each_safe(lchunk, ltemp, &transport->transmitted) {
+ chunk = list_entry(lchunk, struct sctp_chunk,
+ transmitted_list);
+
+ /* If the chunk is abandoned, move it to abandoned list. */
+ if (sctp_chunk_abandoned(chunk)) {
+ list_del_init(lchunk);
+ sctp_insert_list(&q->abandoned, lchunk);
+
+ /* If this chunk has not been previousely acked,
+ * stop considering it 'outstanding'. Our peer
+ * will most likely never see it since it will
+ * not be retransmitted
+ */
+ if (!chunk->tsn_gap_acked) {
+ if (chunk->transport)
+ chunk->transport->flight_size -=
+ sctp_data_size(chunk);
+ q->outstanding_bytes -= sctp_data_size(chunk);
+ q->asoc->peer.rwnd += sctp_data_size(chunk);
+ }
+ continue;
+ }
+
+ /* If we are doing retransmission due to a timeout or pmtu
+ * discovery, only the chunks that are not yet acked should
+ * be added to the retransmit queue.
+ */
+ if ((reason == SCTP_RTXR_FAST_RTX &&
+ (chunk->fast_retransmit == SCTP_NEED_FRTX)) ||
+ (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) {
+ /* RFC 2960 6.2.1 Processing a Received SACK
+ *
+ * C) Any time a DATA chunk is marked for
+ * retransmission (via either T3-rtx timer expiration
+ * (Section 6.3.3) or via fast retransmit
+ * (Section 7.2.4)), add the data size of those
+ * chunks to the rwnd.
+ */
+ q->asoc->peer.rwnd += sctp_data_size(chunk);
+ q->outstanding_bytes -= sctp_data_size(chunk);
+ if (chunk->transport)
+ transport->flight_size -= sctp_data_size(chunk);
+
+ /* sctpimpguide-05 Section 2.8.2
+ * M5) If a T3-rtx timer expires, the
+ * 'TSN.Missing.Report' of all affected TSNs is set
+ * to 0.
+ */
+ chunk->tsn_missing_report = 0;
+
+ /* If a chunk that is being used for RTT measurement
+ * has to be retransmitted, we cannot use this chunk
+ * anymore for RTT measurements. Reset rto_pending so
+ * that a new RTT measurement is started when a new
+ * data chunk is sent.
+ */
+ if (chunk->rtt_in_progress) {
+ chunk->rtt_in_progress = 0;
+ transport->rto_pending = 0;
+ }
+
+ /* Move the chunk to the retransmit queue. The chunks
+ * on the retransmit queue are always kept in order.
+ */
+ list_del_init(lchunk);
+ sctp_insert_list(&q->retransmit, lchunk);
+ }
+ }
+
+ pr_debug("%s: transport:%p, reason:%d, cwnd:%d, ssthresh:%d, "
+ "flight_size:%d, pba:%d\n", __func__, transport, reason,
+ transport->cwnd, transport->ssthresh, transport->flight_size,
+ transport->partial_bytes_acked);
+}
+
+/* Mark all the eligible packets on a transport for retransmission and force
+ * one packet out.
+ */
+void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
+ enum sctp_retransmit_reason reason)
+{
+ struct net *net = sock_net(q->asoc->base.sk);
+
+ switch (reason) {
+ case SCTP_RTXR_T3_RTX:
+ SCTP_INC_STATS(net, SCTP_MIB_T3_RETRANSMITS);
+ sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX);
+ /* Update the retran path if the T3-rtx timer has expired for
+ * the current retran path.
+ */
+ if (transport == transport->asoc->peer.retran_path)
+ sctp_assoc_update_retran_path(transport->asoc);
+ transport->asoc->rtx_data_chunks +=
+ transport->asoc->unack_data;
+ break;
+ case SCTP_RTXR_FAST_RTX:
+ SCTP_INC_STATS(net, SCTP_MIB_FAST_RETRANSMITS);
+ sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX);
+ q->fast_rtx = 1;
+ break;
+ case SCTP_RTXR_PMTUD:
+ SCTP_INC_STATS(net, SCTP_MIB_PMTUD_RETRANSMITS);
+ break;
+ case SCTP_RTXR_T1_RTX:
+ SCTP_INC_STATS(net, SCTP_MIB_T1_RETRANSMITS);
+ transport->asoc->init_retries++;
+ break;
+ default:
+ BUG();
+ }
+
+ sctp_retransmit_mark(q, transport, reason);
+
+ /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
+ * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
+ * following the procedures outlined in C1 - C5.
+ */
+ if (reason == SCTP_RTXR_T3_RTX)
+ q->asoc->stream.si->generate_ftsn(q, q->asoc->ctsn_ack_point);
+
+ /* Flush the queues only on timeout, since fast_rtx is only
+ * triggered during sack processing and the queue
+ * will be flushed at the end.
+ */
+ if (reason != SCTP_RTXR_FAST_RTX)
+ sctp_outq_flush(q, /* rtx_timeout */ 1, GFP_ATOMIC);
+}
+
+/*
+ * Transmit DATA chunks on the retransmit queue. Upon return from
+ * __sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
+ * need to be transmitted by the caller.
+ * We assume that pkt->transport has already been set.
+ *
+ * The return value is a normal kernel error return value.
+ */
+static int __sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
+ int rtx_timeout, int *start_timer, gfp_t gfp)
+{
+ struct sctp_transport *transport = pkt->transport;
+ struct sctp_chunk *chunk, *chunk1;
+ struct list_head *lqueue;
+ enum sctp_xmit status;
+ int error = 0;
+ int timer = 0;
+ int done = 0;
+ int fast_rtx;
+
+ lqueue = &q->retransmit;
+ fast_rtx = q->fast_rtx;
+
+ /* This loop handles time-out retransmissions, fast retransmissions,
+ * and retransmissions due to opening of whindow.
+ *
+ * RFC 2960 6.3.3 Handle T3-rtx Expiration
+ *
+ * E3) Determine how many of the earliest (i.e., lowest TSN)
+ * outstanding DATA chunks for the address for which the
+ * T3-rtx has expired will fit into a single packet, subject
+ * to the MTU constraint for the path corresponding to the
+ * destination transport address to which the retransmission
+ * is being sent (this may be different from the address for
+ * which the timer expires [see Section 6.4]). Call this value
+ * K. Bundle and retransmit those K DATA chunks in a single
+ * packet to the destination endpoint.
+ *
+ * [Just to be painfully clear, if we are retransmitting
+ * because a timeout just happened, we should send only ONE
+ * packet of retransmitted data.]
+ *
+ * For fast retransmissions we also send only ONE packet. However,
+ * if we are just flushing the queue due to open window, we'll
+ * try to send as much as possible.
+ */
+ list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) {
+ /* If the chunk is abandoned, move it to abandoned list. */
+ if (sctp_chunk_abandoned(chunk)) {
+ list_del_init(&chunk->transmitted_list);
+ sctp_insert_list(&q->abandoned,
+ &chunk->transmitted_list);
+ continue;
+ }
+
+ /* Make sure that Gap Acked TSNs are not retransmitted. A
+ * simple approach is just to move such TSNs out of the
+ * way and into a 'transmitted' queue and skip to the
+ * next chunk.
+ */
+ if (chunk->tsn_gap_acked) {
+ list_move_tail(&chunk->transmitted_list,
+ &transport->transmitted);
+ continue;
+ }
+
+ /* If we are doing fast retransmit, ignore non-fast_rtransmit
+ * chunks
+ */
+ if (fast_rtx && !chunk->fast_retransmit)
+ continue;
+
+redo:
+ /* Attempt to append this chunk to the packet. */
+ status = sctp_packet_append_chunk(pkt, chunk);
+
+ switch (status) {
+ case SCTP_XMIT_PMTU_FULL:
+ if (!pkt->has_data && !pkt->has_cookie_echo) {
+ /* If this packet did not contain DATA then
+ * retransmission did not happen, so do it
+ * again. We'll ignore the error here since
+ * control chunks are already freed so there
+ * is nothing we can do.
+ */
+ sctp_packet_transmit(pkt, gfp);
+ goto redo;
+ }
+
+ /* Send this packet. */
+ error = sctp_packet_transmit(pkt, gfp);
+
+ /* If we are retransmitting, we should only
+ * send a single packet.
+ * Otherwise, try appending this chunk again.
+ */
+ if (rtx_timeout || fast_rtx)
+ done = 1;
+ else
+ goto redo;
+
+ /* Bundle next chunk in the next round. */
+ break;
+
+ case SCTP_XMIT_RWND_FULL:
+ /* Send this packet. */
+ error = sctp_packet_transmit(pkt, gfp);
+
+ /* Stop sending DATA as there is no more room
+ * at the receiver.
+ */
+ done = 1;
+ break;
+
+ case SCTP_XMIT_DELAY:
+ /* Send this packet. */
+ error = sctp_packet_transmit(pkt, gfp);
+
+ /* Stop sending DATA because of nagle delay. */
+ done = 1;
+ break;
+
+ default:
+ /* The append was successful, so add this chunk to
+ * the transmitted list.
+ */
+ list_move_tail(&chunk->transmitted_list,
+ &transport->transmitted);
+
+ /* Mark the chunk as ineligible for fast retransmit
+ * after it is retransmitted.
+ */
+ if (chunk->fast_retransmit == SCTP_NEED_FRTX)
+ chunk->fast_retransmit = SCTP_DONT_FRTX;
+
+ q->asoc->stats.rtxchunks++;
+ break;
+ }
+
+ /* Set the timer if there were no errors */
+ if (!error && !timer)
+ timer = 1;
+
+ if (done)
+ break;
+ }
+
+ /* If we are here due to a retransmit timeout or a fast
+ * retransmit and if there are any chunks left in the retransmit
+ * queue that could not fit in the PMTU sized packet, they need
+ * to be marked as ineligible for a subsequent fast retransmit.
+ */
+ if (rtx_timeout || fast_rtx) {
+ list_for_each_entry(chunk1, lqueue, transmitted_list) {
+ if (chunk1->fast_retransmit == SCTP_NEED_FRTX)
+ chunk1->fast_retransmit = SCTP_DONT_FRTX;
+ }
+ }
+
+ *start_timer = timer;
+
+ /* Clear fast retransmit hint */
+ if (fast_rtx)
+ q->fast_rtx = 0;
+
+ return error;
+}
+
+/* Cork the outqueue so queued chunks are really queued. */
+void sctp_outq_uncork(struct sctp_outq *q, gfp_t gfp)
+{
+ if (q->cork)
+ q->cork = 0;
+
+ sctp_outq_flush(q, 0, gfp);
+}
+
+static int sctp_packet_singleton(struct sctp_transport *transport,
+ struct sctp_chunk *chunk, gfp_t gfp)
+{
+ const struct sctp_association *asoc = transport->asoc;
+ const __u16 sport = asoc->base.bind_addr.port;
+ const __u16 dport = asoc->peer.port;
+ const __u32 vtag = asoc->peer.i.init_tag;
+ struct sctp_packet singleton;
+
+ sctp_packet_init(&singleton, transport, sport, dport);
+ sctp_packet_config(&singleton, vtag, 0);
+ sctp_packet_append_chunk(&singleton, chunk);
+ return sctp_packet_transmit(&singleton, gfp);
+}
+
+/* Struct to hold the context during sctp outq flush */
+struct sctp_flush_ctx {
+ struct sctp_outq *q;
+ /* Current transport being used. It's NOT the same as curr active one */
+ struct sctp_transport *transport;
+ /* These transports have chunks to send. */
+ struct list_head transport_list;
+ struct sctp_association *asoc;
+ /* Packet on the current transport above */
+ struct sctp_packet *packet;
+ gfp_t gfp;
+};
+
+/* transport: current transport */
+static void sctp_outq_select_transport(struct sctp_flush_ctx *ctx,
+ struct sctp_chunk *chunk)
+{
+ struct sctp_transport *new_transport = chunk->transport;
+
+ if (!new_transport) {
+ if (!sctp_chunk_is_data(chunk)) {
+ /* If we have a prior transport pointer, see if
+ * the destination address of the chunk
+ * matches the destination address of the
+ * current transport. If not a match, then
+ * try to look up the transport with a given
+ * destination address. We do this because
+ * after processing ASCONFs, we may have new
+ * transports created.
+ */
+ if (ctx->transport && sctp_cmp_addr_exact(&chunk->dest,
+ &ctx->transport->ipaddr))
+ new_transport = ctx->transport;
+ else
+ new_transport = sctp_assoc_lookup_paddr(ctx->asoc,
+ &chunk->dest);
+ }
+
+ /* if we still don't have a new transport, then
+ * use the current active path.
+ */
+ if (!new_transport)
+ new_transport = ctx->asoc->peer.active_path;
+ } else {
+ __u8 type;
+
+ switch (new_transport->state) {
+ case SCTP_INACTIVE:
+ case SCTP_UNCONFIRMED:
+ case SCTP_PF:
+ /* If the chunk is Heartbeat or Heartbeat Ack,
+ * send it to chunk->transport, even if it's
+ * inactive.
+ *
+ * 3.3.6 Heartbeat Acknowledgement:
+ * ...
+ * A HEARTBEAT ACK is always sent to the source IP
+ * address of the IP datagram containing the
+ * HEARTBEAT chunk to which this ack is responding.
+ * ...
+ *
+ * ASCONF_ACKs also must be sent to the source.
+ */
+ type = chunk->chunk_hdr->type;
+ if (type != SCTP_CID_HEARTBEAT &&
+ type != SCTP_CID_HEARTBEAT_ACK &&
+ type != SCTP_CID_ASCONF_ACK)
+ new_transport = ctx->asoc->peer.active_path;
+ break;
+ default:
+ break;
+ }
+ }
+
+ /* Are we switching transports? Take care of transport locks. */
+ if (new_transport != ctx->transport) {
+ ctx->transport = new_transport;
+ ctx->packet = &ctx->transport->packet;
+
+ if (list_empty(&ctx->transport->send_ready))
+ list_add_tail(&ctx->transport->send_ready,
+ &ctx->transport_list);
+
+ sctp_packet_config(ctx->packet,
+ ctx->asoc->peer.i.init_tag,
+ ctx->asoc->peer.ecn_capable);
+ /* We've switched transports, so apply the
+ * Burst limit to the new transport.
+ */
+ sctp_transport_burst_limited(ctx->transport);
+ }
+}
+
+static void sctp_outq_flush_ctrl(struct sctp_flush_ctx *ctx)
+{
+ struct sctp_chunk *chunk, *tmp;
+ enum sctp_xmit status;
+ int one_packet, error;
+
+ list_for_each_entry_safe(chunk, tmp, &ctx->q->control_chunk_list, list) {
+ one_packet = 0;
+
+ /* RFC 5061, 5.3
+ * F1) This means that until such time as the ASCONF
+ * containing the add is acknowledged, the sender MUST
+ * NOT use the new IP address as a source for ANY SCTP
+ * packet except on carrying an ASCONF Chunk.
+ */
+ if (ctx->asoc->src_out_of_asoc_ok &&
+ chunk->chunk_hdr->type != SCTP_CID_ASCONF)
+ continue;
+
+ list_del_init(&chunk->list);
+
+ /* Pick the right transport to use. Should always be true for
+ * the first chunk as we don't have a transport by then.
+ */
+ sctp_outq_select_transport(ctx, chunk);
+
+ switch (chunk->chunk_hdr->type) {
+ /* 6.10 Bundling
+ * ...
+ * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
+ * COMPLETE with any other chunks. [Send them immediately.]
+ */
+ case SCTP_CID_INIT:
+ case SCTP_CID_INIT_ACK:
+ case SCTP_CID_SHUTDOWN_COMPLETE:
+ error = sctp_packet_singleton(ctx->transport, chunk,
+ ctx->gfp);
+ if (error < 0) {
+ ctx->asoc->base.sk->sk_err = -error;
+ return;
+ }
+ break;
+
+ case SCTP_CID_ABORT:
+ if (sctp_test_T_bit(chunk))
+ ctx->packet->vtag = ctx->asoc->c.my_vtag;
+ /* fallthru */
+
+ /* The following chunks are "response" chunks, i.e.
+ * they are generated in response to something we
+ * received. If we are sending these, then we can
+ * send only 1 packet containing these chunks.
+ */
+ case SCTP_CID_HEARTBEAT_ACK:
+ case SCTP_CID_SHUTDOWN_ACK:
+ case SCTP_CID_COOKIE_ACK:
+ case SCTP_CID_COOKIE_ECHO:
+ case SCTP_CID_ERROR:
+ case SCTP_CID_ECN_CWR:
+ case SCTP_CID_ASCONF_ACK:
+ one_packet = 1;
+ /* Fall through */
+
+ case SCTP_CID_SACK:
+ case SCTP_CID_HEARTBEAT:
+ case SCTP_CID_SHUTDOWN:
+ case SCTP_CID_ECN_ECNE:
+ case SCTP_CID_ASCONF:
+ case SCTP_CID_FWD_TSN:
+ case SCTP_CID_I_FWD_TSN:
+ case SCTP_CID_RECONF:
+ status = sctp_packet_transmit_chunk(ctx->packet, chunk,
+ one_packet, ctx->gfp);
+ if (status != SCTP_XMIT_OK) {
+ /* put the chunk back */
+ list_add(&chunk->list, &ctx->q->control_chunk_list);
+ break;
+ }
+
+ ctx->asoc->stats.octrlchunks++;
+ /* PR-SCTP C5) If a FORWARD TSN is sent, the
+ * sender MUST assure that at least one T3-rtx
+ * timer is running.
+ */
+ if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN ||
+ chunk->chunk_hdr->type == SCTP_CID_I_FWD_TSN) {
+ sctp_transport_reset_t3_rtx(ctx->transport);
+ ctx->transport->last_time_sent = jiffies;
+ }
+
+ if (chunk == ctx->asoc->strreset_chunk)
+ sctp_transport_reset_reconf_timer(ctx->transport);
+
+ break;
+
+ default:
+ /* We built a chunk with an illegal type! */
+ BUG();
+ }
+ }
+}
+
+/* Returns false if new data shouldn't be sent */
+static bool sctp_outq_flush_rtx(struct sctp_flush_ctx *ctx,
+ int rtx_timeout)
+{
+ int error, start_timer = 0;
+
+ if (ctx->asoc->peer.retran_path->state == SCTP_UNCONFIRMED)
+ return false;
+
+ if (ctx->transport != ctx->asoc->peer.retran_path) {
+ /* Switch transports & prepare the packet. */
+ ctx->transport = ctx->asoc->peer.retran_path;
+ ctx->packet = &ctx->transport->packet;
+
+ if (list_empty(&ctx->transport->send_ready))
+ list_add_tail(&ctx->transport->send_ready,
+ &ctx->transport_list);
+
+ sctp_packet_config(ctx->packet, ctx->asoc->peer.i.init_tag,
+ ctx->asoc->peer.ecn_capable);
+ }
+
+ error = __sctp_outq_flush_rtx(ctx->q, ctx->packet, rtx_timeout,
+ &start_timer, ctx->gfp);
+ if (error < 0)
+ ctx->asoc->base.sk->sk_err = -error;
+
+ if (start_timer) {
+ sctp_transport_reset_t3_rtx(ctx->transport);
+ ctx->transport->last_time_sent = jiffies;
+ }
+
+ /* This can happen on COOKIE-ECHO resend. Only
+ * one chunk can get bundled with a COOKIE-ECHO.
+ */
+ if (ctx->packet->has_cookie_echo)
+ return false;
+
+ /* Don't send new data if there is still data
+ * waiting to retransmit.
+ */
+ if (!list_empty(&ctx->q->retransmit))
+ return false;
+
+ return true;
+}
+
+static void sctp_outq_flush_data(struct sctp_flush_ctx *ctx,
+ int rtx_timeout)
+{
+ struct sctp_chunk *chunk;
+ enum sctp_xmit status;
+
+ /* Is it OK to send data chunks? */
+ switch (ctx->asoc->state) {
+ case SCTP_STATE_COOKIE_ECHOED:
+ /* Only allow bundling when this packet has a COOKIE-ECHO
+ * chunk.
+ */
+ if (!ctx->packet || !ctx->packet->has_cookie_echo)
+ return;
+
+ /* fall through */
+ case SCTP_STATE_ESTABLISHED:
+ case SCTP_STATE_SHUTDOWN_PENDING:
+ case SCTP_STATE_SHUTDOWN_RECEIVED:
+ break;
+
+ default:
+ /* Do nothing. */
+ return;
+ }
+
+ /* RFC 2960 6.1 Transmission of DATA Chunks
+ *
+ * C) When the time comes for the sender to transmit,
+ * before sending new DATA chunks, the sender MUST
+ * first transmit any outstanding DATA chunks which
+ * are marked for retransmission (limited by the
+ * current cwnd).
+ */
+ if (!list_empty(&ctx->q->retransmit) &&
+ !sctp_outq_flush_rtx(ctx, rtx_timeout))
+ return;
+
+ /* Apply Max.Burst limitation to the current transport in
+ * case it will be used for new data. We are going to
+ * rest it before we return, but we want to apply the limit
+ * to the currently queued data.
+ */
+ if (ctx->transport)
+ sctp_transport_burst_limited(ctx->transport);
+
+ /* Finally, transmit new packets. */
+ while ((chunk = sctp_outq_dequeue_data(ctx->q)) != NULL) {
+ __u32 sid = ntohs(chunk->subh.data_hdr->stream);
+ __u8 stream_state = SCTP_SO(&ctx->asoc->stream, sid)->state;
+
+ /* Has this chunk expired? */
+ if (sctp_chunk_abandoned(chunk)) {
+ sctp_sched_dequeue_done(ctx->q, chunk);
+ sctp_chunk_fail(chunk, 0);
+ sctp_chunk_free(chunk);
+ continue;
+ }
+
+ if (stream_state == SCTP_STREAM_CLOSED) {
+ sctp_outq_head_data(ctx->q, chunk);
+ break;
+ }
+
+ sctp_outq_select_transport(ctx, chunk);
+
+ pr_debug("%s: outq:%p, chunk:%p[%s], tx-tsn:0x%x skb->head:%p skb->users:%d\n",
+ __func__, ctx->q, chunk, chunk && chunk->chunk_hdr ?
+ sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) :
+ "illegal chunk", ntohl(chunk->subh.data_hdr->tsn),
+ chunk->skb ? chunk->skb->head : NULL, chunk->skb ?
+ refcount_read(&chunk->skb->users) : -1);
+
+ /* Add the chunk to the packet. */
+ status = sctp_packet_transmit_chunk(ctx->packet, chunk, 0,
+ ctx->gfp);
+ if (status != SCTP_XMIT_OK) {
+ /* We could not append this chunk, so put
+ * the chunk back on the output queue.
+ */
+ pr_debug("%s: could not transmit tsn:0x%x, status:%d\n",
+ __func__, ntohl(chunk->subh.data_hdr->tsn),
+ status);
+
+ sctp_outq_head_data(ctx->q, chunk);
+ break;
+ }
+
+ /* The sender is in the SHUTDOWN-PENDING state,
+ * The sender MAY set the I-bit in the DATA
+ * chunk header.
+ */
+ if (ctx->asoc->state == SCTP_STATE_SHUTDOWN_PENDING)
+ chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM;
+ if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
+ ctx->asoc->stats.ouodchunks++;
+ else
+ ctx->asoc->stats.oodchunks++;
+
+ /* Only now it's safe to consider this
+ * chunk as sent, sched-wise.
+ */
+ sctp_sched_dequeue_done(ctx->q, chunk);
+
+ list_add_tail(&chunk->transmitted_list,
+ &ctx->transport->transmitted);
+
+ sctp_transport_reset_t3_rtx(ctx->transport);
+ ctx->transport->last_time_sent = jiffies;
+
+ /* Only let one DATA chunk get bundled with a
+ * COOKIE-ECHO chunk.
+ */
+ if (ctx->packet->has_cookie_echo)
+ break;
+ }
+}
+
+static void sctp_outq_flush_transports(struct sctp_flush_ctx *ctx)
+{
+ struct list_head *ltransport;
+ struct sctp_packet *packet;
+ struct sctp_transport *t;
+ int error = 0;
+
+ while ((ltransport = sctp_list_dequeue(&ctx->transport_list)) != NULL) {
+ t = list_entry(ltransport, struct sctp_transport, send_ready);
+ packet = &t->packet;
+ if (!sctp_packet_empty(packet)) {
+ error = sctp_packet_transmit(packet, ctx->gfp);
+ if (error < 0)
+ ctx->q->asoc->base.sk->sk_err = -error;
+ }
+
+ /* Clear the burst limited state, if any */
+ sctp_transport_burst_reset(t);
+ }
+}
+
+/* Try to flush an outqueue.
+ *
+ * Description: Send everything in q which we legally can, subject to
+ * congestion limitations.
+ * * Note: This function can be called from multiple contexts so appropriate
+ * locking concerns must be made. Today we use the sock lock to protect
+ * this function.
+ */
+
+static void sctp_outq_flush(struct sctp_outq *q, int rtx_timeout, gfp_t gfp)
+{
+ struct sctp_flush_ctx ctx = {
+ .q = q,
+ .transport = NULL,
+ .transport_list = LIST_HEAD_INIT(ctx.transport_list),
+ .asoc = q->asoc,
+ .packet = NULL,
+ .gfp = gfp,
+ };
+
+ /* 6.10 Bundling
+ * ...
+ * When bundling control chunks with DATA chunks, an
+ * endpoint MUST place control chunks first in the outbound
+ * SCTP packet. The transmitter MUST transmit DATA chunks
+ * within a SCTP packet in increasing order of TSN.
+ * ...
+ */
+
+ sctp_outq_flush_ctrl(&ctx);
+
+ if (q->asoc->src_out_of_asoc_ok)
+ goto sctp_flush_out;
+
+ sctp_outq_flush_data(&ctx, rtx_timeout);
+
+sctp_flush_out:
+
+ sctp_outq_flush_transports(&ctx);
+}
+
+/* Update unack_data based on the incoming SACK chunk */
+static void sctp_sack_update_unack_data(struct sctp_association *assoc,
+ struct sctp_sackhdr *sack)
+{
+ union sctp_sack_variable *frags;
+ __u16 unack_data;
+ int i;
+
+ unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1;
+
+ frags = sack->variable;
+ for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) {
+ unack_data -= ((ntohs(frags[i].gab.end) -
+ ntohs(frags[i].gab.start) + 1));
+ }
+
+ assoc->unack_data = unack_data;
+}
+
+/* This is where we REALLY process a SACK.
+ *
+ * Process the SACK against the outqueue. Mostly, this just frees
+ * things off the transmitted queue.
+ */
+int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk)
+{
+ struct sctp_association *asoc = q->asoc;
+ struct sctp_sackhdr *sack = chunk->subh.sack_hdr;
+ struct sctp_transport *transport;
+ struct sctp_chunk *tchunk = NULL;
+ struct list_head *lchunk, *transport_list, *temp;
+ union sctp_sack_variable *frags = sack->variable;
+ __u32 sack_ctsn, ctsn, tsn;
+ __u32 highest_tsn, highest_new_tsn;
+ __u32 sack_a_rwnd;
+ unsigned int outstanding;
+ struct sctp_transport *primary = asoc->peer.primary_path;
+ int count_of_newacks = 0;
+ int gap_ack_blocks;
+ u8 accum_moved = 0;
+
+ /* Grab the association's destination address list. */
+ transport_list = &asoc->peer.transport_addr_list;
+
+ sack_ctsn = ntohl(sack->cum_tsn_ack);
+ gap_ack_blocks = ntohs(sack->num_gap_ack_blocks);
+ asoc->stats.gapcnt += gap_ack_blocks;
+ /*
+ * SFR-CACC algorithm:
+ * On receipt of a SACK the sender SHOULD execute the
+ * following statements.
+ *
+ * 1) If the cumulative ack in the SACK passes next tsn_at_change
+ * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
+ * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
+ * all destinations.
+ * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
+ * is set the receiver of the SACK MUST take the following actions:
+ *
+ * A) Initialize the cacc_saw_newack to 0 for all destination
+ * addresses.
+ *
+ * Only bother if changeover_active is set. Otherwise, this is
+ * totally suboptimal to do on every SACK.
+ */
+ if (primary->cacc.changeover_active) {
+ u8 clear_cycling = 0;
+
+ if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) {
+ primary->cacc.changeover_active = 0;
+ clear_cycling = 1;
+ }
+
+ if (clear_cycling || gap_ack_blocks) {
+ list_for_each_entry(transport, transport_list,
+ transports) {
+ if (clear_cycling)
+ transport->cacc.cycling_changeover = 0;
+ if (gap_ack_blocks)
+ transport->cacc.cacc_saw_newack = 0;
+ }
+ }
+ }
+
+ /* Get the highest TSN in the sack. */
+ highest_tsn = sack_ctsn;
+ if (gap_ack_blocks)
+ highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end);
+
+ if (TSN_lt(asoc->highest_sacked, highest_tsn))
+ asoc->highest_sacked = highest_tsn;
+
+ highest_new_tsn = sack_ctsn;
+
+ /* Run through the retransmit queue. Credit bytes received
+ * and free those chunks that we can.
+ */
+ sctp_check_transmitted(q, &q->retransmit, NULL, NULL, sack, &highest_new_tsn);
+
+ /* Run through the transmitted queue.
+ * Credit bytes received and free those chunks which we can.
+ *
+ * This is a MASSIVE candidate for optimization.
+ */
+ list_for_each_entry(transport, transport_list, transports) {
+ sctp_check_transmitted(q, &transport->transmitted,
+ transport, &chunk->source, sack,
+ &highest_new_tsn);
+ /*
+ * SFR-CACC algorithm:
+ * C) Let count_of_newacks be the number of
+ * destinations for which cacc_saw_newack is set.
+ */
+ if (transport->cacc.cacc_saw_newack)
+ count_of_newacks++;
+ }
+
+ /* Move the Cumulative TSN Ack Point if appropriate. */
+ if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) {
+ asoc->ctsn_ack_point = sack_ctsn;
+ accum_moved = 1;
+ }
+
+ if (gap_ack_blocks) {
+
+ if (asoc->fast_recovery && accum_moved)
+ highest_new_tsn = highest_tsn;
+
+ list_for_each_entry(transport, transport_list, transports)
+ sctp_mark_missing(q, &transport->transmitted, transport,
+ highest_new_tsn, count_of_newacks);
+ }
+
+ /* Update unack_data field in the assoc. */
+ sctp_sack_update_unack_data(asoc, sack);
+
+ ctsn = asoc->ctsn_ack_point;
+
+ /* Throw away stuff rotting on the sack queue. */
+ list_for_each_safe(lchunk, temp, &q->sacked) {
+ tchunk = list_entry(lchunk, struct sctp_chunk,
+ transmitted_list);
+ tsn = ntohl(tchunk->subh.data_hdr->tsn);
+ if (TSN_lte(tsn, ctsn)) {
+ list_del_init(&tchunk->transmitted_list);
+ if (asoc->peer.prsctp_capable &&
+ SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))
+ asoc->sent_cnt_removable--;
+ sctp_chunk_free(tchunk);
+ }
+ }
+
+ /* ii) Set rwnd equal to the newly received a_rwnd minus the
+ * number of bytes still outstanding after processing the
+ * Cumulative TSN Ack and the Gap Ack Blocks.
+ */
+
+ sack_a_rwnd = ntohl(sack->a_rwnd);
+ asoc->peer.zero_window_announced = !sack_a_rwnd;
+ outstanding = q->outstanding_bytes;
+
+ if (outstanding < sack_a_rwnd)
+ sack_a_rwnd -= outstanding;
+ else
+ sack_a_rwnd = 0;
+
+ asoc->peer.rwnd = sack_a_rwnd;
+
+ asoc->stream.si->generate_ftsn(q, sack_ctsn);
+
+ pr_debug("%s: sack cumulative tsn ack:0x%x\n", __func__, sack_ctsn);
+ pr_debug("%s: cumulative tsn ack of assoc:%p is 0x%x, "
+ "advertised peer ack point:0x%x\n", __func__, asoc, ctsn,
+ asoc->adv_peer_ack_point);
+
+ return sctp_outq_is_empty(q);
+}
+
+/* Is the outqueue empty?
+ * The queue is empty when we have not pending data, no in-flight data
+ * and nothing pending retransmissions.
+ */
+int sctp_outq_is_empty(const struct sctp_outq *q)
+{
+ return q->out_qlen == 0 && q->outstanding_bytes == 0 &&
+ list_empty(&q->retransmit);
+}
+
+/********************************************************************
+ * 2nd Level Abstractions
+ ********************************************************************/
+
+/* Go through a transport's transmitted list or the association's retransmit
+ * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
+ * The retransmit list will not have an associated transport.
+ *
+ * I added coherent debug information output. --xguo
+ *
+ * Instead of printing 'sacked' or 'kept' for each TSN on the
+ * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
+ * KEPT TSN6-TSN7, etc.
+ */
+static void sctp_check_transmitted(struct sctp_outq *q,
+ struct list_head *transmitted_queue,
+ struct sctp_transport *transport,
+ union sctp_addr *saddr,
+ struct sctp_sackhdr *sack,
+ __u32 *highest_new_tsn_in_sack)
+{
+ struct list_head *lchunk;
+ struct sctp_chunk *tchunk;
+ struct list_head tlist;
+ __u32 tsn;
+ __u32 sack_ctsn;
+ __u32 rtt;
+ __u8 restart_timer = 0;
+ int bytes_acked = 0;
+ int migrate_bytes = 0;
+ bool forward_progress = false;
+
+ sack_ctsn = ntohl(sack->cum_tsn_ack);
+
+ INIT_LIST_HEAD(&tlist);
+
+ /* The while loop will skip empty transmitted queues. */
+ while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) {
+ tchunk = list_entry(lchunk, struct sctp_chunk,
+ transmitted_list);
+
+ if (sctp_chunk_abandoned(tchunk)) {
+ /* Move the chunk to abandoned list. */
+ sctp_insert_list(&q->abandoned, lchunk);
+
+ /* If this chunk has not been acked, stop
+ * considering it as 'outstanding'.
+ */
+ if (transmitted_queue != &q->retransmit &&
+ !tchunk->tsn_gap_acked) {
+ if (tchunk->transport)
+ tchunk->transport->flight_size -=
+ sctp_data_size(tchunk);
+ q->outstanding_bytes -= sctp_data_size(tchunk);
+ }
+ continue;
+ }
+
+ tsn = ntohl(tchunk->subh.data_hdr->tsn);
+ if (sctp_acked(sack, tsn)) {
+ /* If this queue is the retransmit queue, the
+ * retransmit timer has already reclaimed
+ * the outstanding bytes for this chunk, so only
+ * count bytes associated with a transport.
+ */
+ if (transport && !tchunk->tsn_gap_acked) {
+ /* If this chunk is being used for RTT
+ * measurement, calculate the RTT and update
+ * the RTO using this value.
+ *
+ * 6.3.1 C5) Karn's algorithm: RTT measurements
+ * MUST NOT be made using packets that were
+ * retransmitted (and thus for which it is
+ * ambiguous whether the reply was for the
+ * first instance of the packet or a later
+ * instance).
+ */
+ if (!sctp_chunk_retransmitted(tchunk) &&
+ tchunk->rtt_in_progress) {
+ tchunk->rtt_in_progress = 0;
+ rtt = jiffies - tchunk->sent_at;
+ sctp_transport_update_rto(transport,
+ rtt);
+ }
+
+ if (TSN_lte(tsn, sack_ctsn)) {
+ /*
+ * SFR-CACC algorithm:
+ * 2) If the SACK contains gap acks
+ * and the flag CHANGEOVER_ACTIVE is
+ * set the receiver of the SACK MUST
+ * take the following action:
+ *
+ * B) For each TSN t being acked that
+ * has not been acked in any SACK so
+ * far, set cacc_saw_newack to 1 for
+ * the destination that the TSN was
+ * sent to.
+ */
+ if (sack->num_gap_ack_blocks &&
+ q->asoc->peer.primary_path->cacc.
+ changeover_active)
+ transport->cacc.cacc_saw_newack
+ = 1;
+ }
+ }
+
+ /* If the chunk hasn't been marked as ACKED,
+ * mark it and account bytes_acked if the
+ * chunk had a valid transport (it will not
+ * have a transport if ASCONF had deleted it
+ * while DATA was outstanding).
+ */
+ if (!tchunk->tsn_gap_acked) {
+ tchunk->tsn_gap_acked = 1;
+ if (TSN_lt(*highest_new_tsn_in_sack, tsn))
+ *highest_new_tsn_in_sack = tsn;
+ bytes_acked += sctp_data_size(tchunk);
+ if (!tchunk->transport)
+ migrate_bytes += sctp_data_size(tchunk);
+ forward_progress = true;
+ }
+
+ if (TSN_lte(tsn, sack_ctsn)) {
+ /* RFC 2960 6.3.2 Retransmission Timer Rules
+ *
+ * R3) Whenever a SACK is received
+ * that acknowledges the DATA chunk
+ * with the earliest outstanding TSN
+ * for that address, restart T3-rtx
+ * timer for that address with its
+ * current RTO.
+ */
+ restart_timer = 1;
+ forward_progress = true;
+
+ list_add_tail(&tchunk->transmitted_list,
+ &q->sacked);
+ } else {
+ /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
+ * M2) Each time a SACK arrives reporting
+ * 'Stray DATA chunk(s)' record the highest TSN
+ * reported as newly acknowledged, call this
+ * value 'HighestTSNinSack'. A newly
+ * acknowledged DATA chunk is one not
+ * previously acknowledged in a SACK.
+ *
+ * When the SCTP sender of data receives a SACK
+ * chunk that acknowledges, for the first time,
+ * the receipt of a DATA chunk, all the still
+ * unacknowledged DATA chunks whose TSN is
+ * older than that newly acknowledged DATA
+ * chunk, are qualified as 'Stray DATA chunks'.
+ */
+ list_add_tail(lchunk, &tlist);
+ }
+ } else {
+ if (tchunk->tsn_gap_acked) {
+ pr_debug("%s: receiver reneged on data TSN:0x%x\n",
+ __func__, tsn);
+
+ tchunk->tsn_gap_acked = 0;
+
+ if (tchunk->transport)
+ bytes_acked -= sctp_data_size(tchunk);
+
+ /* RFC 2960 6.3.2 Retransmission Timer Rules
+ *
+ * R4) Whenever a SACK is received missing a
+ * TSN that was previously acknowledged via a
+ * Gap Ack Block, start T3-rtx for the
+ * destination address to which the DATA
+ * chunk was originally
+ * transmitted if it is not already running.
+ */
+ restart_timer = 1;
+ }
+
+ list_add_tail(lchunk, &tlist);
+ }
+ }
+
+ if (transport) {
+ if (bytes_acked) {
+ struct sctp_association *asoc = transport->asoc;
+
+ /* We may have counted DATA that was migrated
+ * to this transport due to DEL-IP operation.
+ * Subtract those bytes, since the were never
+ * send on this transport and shouldn't be
+ * credited to this transport.
+ */
+ bytes_acked -= migrate_bytes;
+
+ /* 8.2. When an outstanding TSN is acknowledged,
+ * the endpoint shall clear the error counter of
+ * the destination transport address to which the
+ * DATA chunk was last sent.
+ * The association's overall error counter is
+ * also cleared.
+ */
+ transport->error_count = 0;
+ transport->asoc->overall_error_count = 0;
+ forward_progress = true;
+
+ /*
+ * While in SHUTDOWN PENDING, we may have started
+ * the T5 shutdown guard timer after reaching the
+ * retransmission limit. Stop that timer as soon
+ * as the receiver acknowledged any data.
+ */
+ if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING &&
+ del_timer(&asoc->timers
+ [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]))
+ sctp_association_put(asoc);
+
+ /* Mark the destination transport address as
+ * active if it is not so marked.
+ */
+ if ((transport->state == SCTP_INACTIVE ||
+ transport->state == SCTP_UNCONFIRMED) &&
+ sctp_cmp_addr_exact(&transport->ipaddr, saddr)) {
+ sctp_assoc_control_transport(
+ transport->asoc,
+ transport,
+ SCTP_TRANSPORT_UP,
+ SCTP_RECEIVED_SACK);
+ }
+
+ sctp_transport_raise_cwnd(transport, sack_ctsn,
+ bytes_acked);
+
+ transport->flight_size -= bytes_acked;
+ if (transport->flight_size == 0)
+ transport->partial_bytes_acked = 0;
+ q->outstanding_bytes -= bytes_acked + migrate_bytes;
+ } else {
+ /* RFC 2960 6.1, sctpimpguide-06 2.15.2
+ * When a sender is doing zero window probing, it
+ * should not timeout the association if it continues
+ * to receive new packets from the receiver. The
+ * reason is that the receiver MAY keep its window
+ * closed for an indefinite time.
+ * A sender is doing zero window probing when the
+ * receiver's advertised window is zero, and there is
+ * only one data chunk in flight to the receiver.
+ *
+ * Allow the association to timeout while in SHUTDOWN
+ * PENDING or SHUTDOWN RECEIVED in case the receiver
+ * stays in zero window mode forever.
+ */
+ if (!q->asoc->peer.rwnd &&
+ !list_empty(&tlist) &&
+ (sack_ctsn+2 == q->asoc->next_tsn) &&
+ q->asoc->state < SCTP_STATE_SHUTDOWN_PENDING) {
+ pr_debug("%s: sack received for zero window "
+ "probe:%u\n", __func__, sack_ctsn);
+
+ q->asoc->overall_error_count = 0;
+ transport->error_count = 0;
+ }
+ }
+
+ /* RFC 2960 6.3.2 Retransmission Timer Rules
+ *
+ * R2) Whenever all outstanding data sent to an address have
+ * been acknowledged, turn off the T3-rtx timer of that
+ * address.
+ */
+ if (!transport->flight_size) {
+ if (del_timer(&transport->T3_rtx_timer))
+ sctp_transport_put(transport);
+ } else if (restart_timer) {
+ if (!mod_timer(&transport->T3_rtx_timer,
+ jiffies + transport->rto))
+ sctp_transport_hold(transport);
+ }
+
+ if (forward_progress) {
+ if (transport->dst)
+ sctp_transport_dst_confirm(transport);
+ }
+ }
+
+ list_splice(&tlist, transmitted_queue);
+}
+
+/* Mark chunks as missing and consequently may get retransmitted. */
+static void sctp_mark_missing(struct sctp_outq *q,
+ struct list_head *transmitted_queue,
+ struct sctp_transport *transport,
+ __u32 highest_new_tsn_in_sack,
+ int count_of_newacks)
+{
+ struct sctp_chunk *chunk;
+ __u32 tsn;
+ char do_fast_retransmit = 0;
+ struct sctp_association *asoc = q->asoc;
+ struct sctp_transport *primary = asoc->peer.primary_path;
+
+ list_for_each_entry(chunk, transmitted_queue, transmitted_list) {
+
+ tsn = ntohl(chunk->subh.data_hdr->tsn);
+
+ /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
+ * 'Unacknowledged TSN's', if the TSN number of an
+ * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
+ * value, increment the 'TSN.Missing.Report' count on that
+ * chunk if it has NOT been fast retransmitted or marked for
+ * fast retransmit already.
+ */
+ if (chunk->fast_retransmit == SCTP_CAN_FRTX &&
+ !chunk->tsn_gap_acked &&
+ TSN_lt(tsn, highest_new_tsn_in_sack)) {
+
+ /* SFR-CACC may require us to skip marking
+ * this chunk as missing.
+ */
+ if (!transport || !sctp_cacc_skip(primary,
+ chunk->transport,
+ count_of_newacks, tsn)) {
+ chunk->tsn_missing_report++;
+
+ pr_debug("%s: tsn:0x%x missing counter:%d\n",
+ __func__, tsn, chunk->tsn_missing_report);
+ }
+ }
+ /*
+ * M4) If any DATA chunk is found to have a
+ * 'TSN.Missing.Report'
+ * value larger than or equal to 3, mark that chunk for
+ * retransmission and start the fast retransmit procedure.
+ */
+
+ if (chunk->tsn_missing_report >= 3) {
+ chunk->fast_retransmit = SCTP_NEED_FRTX;
+ do_fast_retransmit = 1;
+ }
+ }
+
+ if (transport) {
+ if (do_fast_retransmit)
+ sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX);
+
+ pr_debug("%s: transport:%p, cwnd:%d, ssthresh:%d, "
+ "flight_size:%d, pba:%d\n", __func__, transport,
+ transport->cwnd, transport->ssthresh,
+ transport->flight_size, transport->partial_bytes_acked);
+ }
+}
+
+/* Is the given TSN acked by this packet? */
+static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
+{
+ __u32 ctsn = ntohl(sack->cum_tsn_ack);
+ union sctp_sack_variable *frags;
+ __u16 tsn_offset, blocks;
+ int i;
+
+ if (TSN_lte(tsn, ctsn))
+ goto pass;
+
+ /* 3.3.4 Selective Acknowledgment (SACK) (3):
+ *
+ * Gap Ack Blocks:
+ * These fields contain the Gap Ack Blocks. They are repeated
+ * for each Gap Ack Block up to the number of Gap Ack Blocks
+ * defined in the Number of Gap Ack Blocks field. All DATA
+ * chunks with TSNs greater than or equal to (Cumulative TSN
+ * Ack + Gap Ack Block Start) and less than or equal to
+ * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
+ * Block are assumed to have been received correctly.
+ */
+
+ frags = sack->variable;
+ blocks = ntohs(sack->num_gap_ack_blocks);
+ tsn_offset = tsn - ctsn;
+ for (i = 0; i < blocks; ++i) {
+ if (tsn_offset >= ntohs(frags[i].gab.start) &&
+ tsn_offset <= ntohs(frags[i].gab.end))
+ goto pass;
+ }
+
+ return 0;
+pass:
+ return 1;
+}
+
+static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist,
+ int nskips, __be16 stream)
+{
+ int i;
+
+ for (i = 0; i < nskips; i++) {
+ if (skiplist[i].stream == stream)
+ return i;
+ }
+ return i;
+}
+
+/* Create and add a fwdtsn chunk to the outq's control queue if needed. */
+void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn)
+{
+ struct sctp_association *asoc = q->asoc;
+ struct sctp_chunk *ftsn_chunk = NULL;
+ struct sctp_fwdtsn_skip ftsn_skip_arr[10];
+ int nskips = 0;
+ int skip_pos = 0;
+ __u32 tsn;
+ struct sctp_chunk *chunk;
+ struct list_head *lchunk, *temp;
+
+ if (!asoc->peer.prsctp_capable)
+ return;
+
+ /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
+ * received SACK.
+ *
+ * If (Advanced.Peer.Ack.Point < SackCumAck), then update
+ * Advanced.Peer.Ack.Point to be equal to SackCumAck.
+ */
+ if (TSN_lt(asoc->adv_peer_ack_point, ctsn))
+ asoc->adv_peer_ack_point = ctsn;
+
+ /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
+ * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
+ * the chunk next in the out-queue space is marked as "abandoned" as
+ * shown in the following example:
+ *
+ * Assuming that a SACK arrived with the Cumulative TSN ACK 102
+ * and the Advanced.Peer.Ack.Point is updated to this value:
+ *
+ * out-queue at the end of ==> out-queue after Adv.Ack.Point
+ * normal SACK processing local advancement
+ * ... ...
+ * Adv.Ack.Pt-> 102 acked 102 acked
+ * 103 abandoned 103 abandoned
+ * 104 abandoned Adv.Ack.P-> 104 abandoned
+ * 105 105
+ * 106 acked 106 acked
+ * ... ...
+ *
+ * In this example, the data sender successfully advanced the
+ * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
+ */
+ list_for_each_safe(lchunk, temp, &q->abandoned) {
+ chunk = list_entry(lchunk, struct sctp_chunk,
+ transmitted_list);
+ tsn = ntohl(chunk->subh.data_hdr->tsn);
+
+ /* Remove any chunks in the abandoned queue that are acked by
+ * the ctsn.
+ */
+ if (TSN_lte(tsn, ctsn)) {
+ list_del_init(lchunk);
+ sctp_chunk_free(chunk);
+ } else {
+ if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) {
+ asoc->adv_peer_ack_point = tsn;
+ if (chunk->chunk_hdr->flags &
+ SCTP_DATA_UNORDERED)
+ continue;
+ skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0],
+ nskips,
+ chunk->subh.data_hdr->stream);
+ ftsn_skip_arr[skip_pos].stream =
+ chunk->subh.data_hdr->stream;
+ ftsn_skip_arr[skip_pos].ssn =
+ chunk->subh.data_hdr->ssn;
+ if (skip_pos == nskips)
+ nskips++;
+ if (nskips == 10)
+ break;
+ } else
+ break;
+ }
+ }
+
+ /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
+ * is greater than the Cumulative TSN ACK carried in the received
+ * SACK, the data sender MUST send the data receiver a FORWARD TSN
+ * chunk containing the latest value of the
+ * "Advanced.Peer.Ack.Point".
+ *
+ * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
+ * list each stream and sequence number in the forwarded TSN. This
+ * information will enable the receiver to easily find any
+ * stranded TSN's waiting on stream reorder queues. Each stream
+ * SHOULD only be reported once; this means that if multiple
+ * abandoned messages occur in the same stream then only the
+ * highest abandoned stream sequence number is reported. If the
+ * total size of the FORWARD TSN does NOT fit in a single MTU then
+ * the sender of the FORWARD TSN SHOULD lower the
+ * Advanced.Peer.Ack.Point to the last TSN that will fit in a
+ * single MTU.
+ */
+ if (asoc->adv_peer_ack_point > ctsn)
+ ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point,
+ nskips, &ftsn_skip_arr[0]);
+
+ if (ftsn_chunk) {
+ list_add_tail(&ftsn_chunk->list, &q->control_chunk_list);
+ SCTP_INC_STATS(sock_net(asoc->base.sk), SCTP_MIB_OUTCTRLCHUNKS);
+ }
+}