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Diffstat (limited to 'kernel/net/sctp/outqueue.c')
| -rw-r--r-- | kernel/net/sctp/outqueue.c | 1787 |
1 files changed, 1787 insertions, 0 deletions
diff --git a/kernel/net/sctp/outqueue.c b/kernel/net/sctp/outqueue.c new file mode 100644 index 000000000..7e8f0a117 --- /dev/null +++ b/kernel/net/sctp/outqueue.c @@ -0,0 +1,1787 @@ +/* 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> + +/* 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_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn); + +static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout); + +/* Add data to the front of the queue. */ +static inline void sctp_outq_head_data(struct sctp_outq *q, + struct sctp_chunk *ch) +{ + list_add(&ch->list, &q->out_chunk_list); + q->out_qlen += ch->skb->len; +} + +/* Take data from the front of the queue. */ +static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q) +{ + struct sctp_chunk *ch = NULL; + + if (!list_empty(&q->out_chunk_list)) { + struct list_head *entry = q->out_chunk_list.next; + + ch = list_entry(entry, struct sctp_chunk, list); + list_del_init(entry); + q->out_qlen -= ch->skb->len; + } + return ch; +} +/* Add data chunk to the end of the queue. */ +static inline void sctp_outq_tail_data(struct sctp_outq *q, + struct sctp_chunk *ch) +{ + list_add_tail(&ch->list, &q->out_chunk_list); + q->out_qlen += ch->skb->len; +} + +/* + * 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); +} + +/* 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) { + + /* 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. */ +int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk) +{ + struct net *net = sock_net(q->asoc->base.sk); + int error = 0; + + 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)) { + /* Is it OK to queue data chunks? */ + /* From 9. Termination of Association + * + * When either endpoint performs a shutdown, the + * association on each peer will stop accepting new + * data from its user and only deliver data in queue + * at the time of sending or receiving the SHUTDOWN + * chunk. + */ + switch (q->asoc->state) { + case SCTP_STATE_CLOSED: + case SCTP_STATE_SHUTDOWN_PENDING: + case SCTP_STATE_SHUTDOWN_SENT: + case SCTP_STATE_SHUTDOWN_RECEIVED: + case SCTP_STATE_SHUTDOWN_ACK_SENT: + /* Cannot send after transport endpoint shutdown */ + error = -ESHUTDOWN; + break; + + default: + 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->chunk_hdr->flags & SCTP_DATA_UNORDERED) + SCTP_INC_STATS(net, SCTP_MIB_OUTUNORDERCHUNKS); + else + SCTP_INC_STATS(net, SCTP_MIB_OUTORDERCHUNKS); + break; + } + } else { + list_add_tail(&chunk->list, &q->control_chunk_list); + SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); + } + + if (error < 0) + return error; + + if (!q->cork) + error = sctp_outq_flush(q, 0); + + return error; +} + +/* 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); +} + +/* 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; + } + + chunk->resent = 1; + + /* 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, + sctp_retransmit_reason_t reason) +{ + struct net *net = sock_net(q->asoc->base.sk); + int error = 0; + + 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) + sctp_generate_fwdtsn(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) + error = sctp_outq_flush(q, /* rtx_timeout */ 1); + + if (error) + q->asoc->base.sk->sk_err = -error; +} + +/* + * 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) +{ + struct list_head *lqueue; + struct sctp_transport *transport = pkt->transport; + sctp_xmit_t status; + struct sctp_chunk *chunk, *chunk1; + int fast_rtx; + int error = 0; + int timer = 0; + int done = 0; + + 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); + goto redo; + } + + /* Send this packet. */ + error = sctp_packet_transmit(pkt); + + /* 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); + + /* 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); + + /* 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. */ +int sctp_outq_uncork(struct sctp_outq *q) +{ + if (q->cork) + q->cork = 0; + + return sctp_outq_flush(q, 0); +} + + +/* + * 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 int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout) +{ + struct sctp_packet *packet; + struct sctp_packet singleton; + struct sctp_association *asoc = q->asoc; + __u16 sport = asoc->base.bind_addr.port; + __u16 dport = asoc->peer.port; + __u32 vtag = asoc->peer.i.init_tag; + struct sctp_transport *transport = NULL; + struct sctp_transport *new_transport; + struct sctp_chunk *chunk, *tmp; + sctp_xmit_t status; + int error = 0; + int start_timer = 0; + int one_packet = 0; + + /* These transports have chunks to send. */ + struct list_head transport_list; + struct list_head *ltransport; + + INIT_LIST_HEAD(&transport_list); + packet = NULL; + + /* + * 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. + * ... + */ + + list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { + /* 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 (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. */ + new_transport = chunk->transport; + + if (!new_transport) { + /* + * 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 (transport && + sctp_cmp_addr_exact(&chunk->dest, + &transport->ipaddr)) + new_transport = transport; + else + new_transport = sctp_assoc_lookup_paddr(asoc, + &chunk->dest); + + /* if we still don't have a new transport, then + * use the current active path. + */ + if (!new_transport) + new_transport = asoc->peer.active_path; + } else if ((new_transport->state == SCTP_INACTIVE) || + (new_transport->state == SCTP_UNCONFIRMED) || + (new_transport->state == 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. + */ + if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT && + chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK && + chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK) + new_transport = asoc->peer.active_path; + } + + /* Are we switching transports? + * Take care of transport locks. + */ + if (new_transport != transport) { + transport = new_transport; + if (list_empty(&transport->send_ready)) { + list_add_tail(&transport->send_ready, + &transport_list); + } + packet = &transport->packet; + sctp_packet_config(packet, vtag, + asoc->peer.ecn_capable); + } + + 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: + sctp_packet_init(&singleton, transport, sport, dport); + sctp_packet_config(&singleton, vtag, 0); + sctp_packet_append_chunk(&singleton, chunk); + error = sctp_packet_transmit(&singleton); + if (error < 0) + return error; + break; + + case SCTP_CID_ABORT: + if (sctp_test_T_bit(chunk)) { + packet->vtag = asoc->c.my_vtag; + } + /* 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: + status = sctp_packet_transmit_chunk(packet, chunk, + one_packet); + if (status != SCTP_XMIT_OK) { + /* put the chunk back */ + list_add(&chunk->list, &q->control_chunk_list); + } else { + 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) + sctp_transport_reset_timers(transport); + } + break; + + default: + /* We built a chunk with an illegal type! */ + BUG(); + } + } + + if (q->asoc->src_out_of_asoc_ok) + goto sctp_flush_out; + + /* Is it OK to send data chunks? */ + switch (asoc->state) { + case SCTP_STATE_COOKIE_ECHOED: + /* Only allow bundling when this packet has a COOKIE-ECHO + * chunk. + */ + if (!packet || !packet->has_cookie_echo) + break; + + /* fallthru */ + case SCTP_STATE_ESTABLISHED: + case SCTP_STATE_SHUTDOWN_PENDING: + case SCTP_STATE_SHUTDOWN_RECEIVED: + /* + * 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(&q->retransmit)) { + if (asoc->peer.retran_path->state == SCTP_UNCONFIRMED) + goto sctp_flush_out; + if (transport == asoc->peer.retran_path) + goto retran; + + /* Switch transports & prepare the packet. */ + + transport = asoc->peer.retran_path; + + if (list_empty(&transport->send_ready)) { + list_add_tail(&transport->send_ready, + &transport_list); + } + + packet = &transport->packet; + sctp_packet_config(packet, vtag, + asoc->peer.ecn_capable); + retran: + error = sctp_outq_flush_rtx(q, packet, + rtx_timeout, &start_timer); + + if (start_timer) + sctp_transport_reset_timers(transport); + + /* This can happen on COOKIE-ECHO resend. Only + * one chunk can get bundled with a COOKIE-ECHO. + */ + if (packet->has_cookie_echo) + goto sctp_flush_out; + + /* Don't send new data if there is still data + * waiting to retransmit. + */ + if (!list_empty(&q->retransmit)) + goto sctp_flush_out; + } + + /* 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 (transport) + sctp_transport_burst_limited(transport); + + /* Finally, transmit new packets. */ + while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { + /* RFC 2960 6.5 Every DATA chunk MUST carry a valid + * stream identifier. + */ + if (chunk->sinfo.sinfo_stream >= + asoc->c.sinit_num_ostreams) { + + /* Mark as failed send. */ + sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM); + sctp_chunk_free(chunk); + continue; + } + + /* Has this chunk expired? */ + if (sctp_chunk_abandoned(chunk)) { + sctp_chunk_fail(chunk, 0); + sctp_chunk_free(chunk); + continue; + } + + /* If there is a specified transport, use it. + * Otherwise, we want to use the active path. + */ + new_transport = chunk->transport; + if (!new_transport || + ((new_transport->state == SCTP_INACTIVE) || + (new_transport->state == SCTP_UNCONFIRMED) || + (new_transport->state == SCTP_PF))) + new_transport = asoc->peer.active_path; + if (new_transport->state == SCTP_UNCONFIRMED) + continue; + + /* Change packets if necessary. */ + if (new_transport != transport) { + transport = new_transport; + + /* Schedule to have this transport's + * packet flushed. + */ + if (list_empty(&transport->send_ready)) { + list_add_tail(&transport->send_ready, + &transport_list); + } + + packet = &transport->packet; + sctp_packet_config(packet, vtag, + asoc->peer.ecn_capable); + /* We've switched transports, so apply the + * Burst limit to the new transport. + */ + sctp_transport_burst_limited(transport); + } + + pr_debug("%s: outq:%p, chunk:%p[%s], tx-tsn:0x%x skb->head:%p " + "skb->users:%d\n", + __func__, 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 ? + atomic_read(&chunk->skb->users) : -1); + + /* Add the chunk to the packet. */ + status = sctp_packet_transmit_chunk(packet, chunk, 0); + + switch (status) { + case SCTP_XMIT_PMTU_FULL: + case SCTP_XMIT_RWND_FULL: + case SCTP_XMIT_DELAY: + /* 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(q, chunk); + goto sctp_flush_out; + + case SCTP_XMIT_OK: + /* The sender is in the SHUTDOWN-PENDING state, + * The sender MAY set the I-bit in the DATA + * chunk header. + */ + if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) + chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM; + if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) + asoc->stats.ouodchunks++; + else + asoc->stats.oodchunks++; + + break; + + default: + BUG(); + } + + /* BUG: We assume that the sctp_packet_transmit() + * call below will succeed all the time and add the + * chunk to the transmitted list and restart the + * timers. + * It is possible that the call can fail under OOM + * conditions. + * + * Is this really a problem? Won't this behave + * like a lost TSN? + */ + list_add_tail(&chunk->transmitted_list, + &transport->transmitted); + + sctp_transport_reset_timers(transport); + + /* Only let one DATA chunk get bundled with a + * COOKIE-ECHO chunk. + */ + if (packet->has_cookie_echo) + goto sctp_flush_out; + } + break; + + default: + /* Do nothing. */ + break; + } + +sctp_flush_out: + + /* Before returning, examine all the transports touched in + * this call. Right now, we bluntly force clear all the + * transports. Things might change after we implement Nagle. + * But such an examination is still required. + * + * --xguo + */ + while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL) { + struct sctp_transport *t = list_entry(ltransport, + struct sctp_transport, + send_ready); + packet = &t->packet; + if (!sctp_packet_empty(packet)) + error = sctp_packet_transmit(packet); + + /* Clear the burst limited state, if any */ + sctp_transport_burst_reset(t); + } + + return error; +} + +/* Update unack_data based on the incoming SACK chunk */ +static void sctp_sack_update_unack_data(struct sctp_association *assoc, + struct sctp_sackhdr *sack) +{ + sctp_sack_variable_t *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; + sctp_sack_variable_t *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); + 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); + outstanding = q->outstanding_bytes; + + if (outstanding < sack_a_rwnd) + sack_a_rwnd -= outstanding; + else + sack_a_rwnd = 0; + + asoc->peer.rwnd = sack_a_rwnd; + + sctp_generate_fwdtsn(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 (!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) { + /* 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 (!tchunk->tsn_gap_acked && + !tchunk->resent && + tchunk->rtt_in_progress) { + tchunk->rtt_in_progress = 0; + rtt = jiffies - tchunk->sent_at; + sctp_transport_update_rto(transport, + rtt); + } + } + + /* 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; + + if (!tchunk->tsn_gap_acked) { + /* + * 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 (transport && + sack->num_gap_ack_blocks && + q->asoc->peer.primary_path->cacc. + changeover_active) + transport->cacc.cacc_saw_newack + = 1; + } + + 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) + dst_confirm(transport->dst); + } + } + + 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) +{ + int i; + sctp_sack_variable_t *frags; + __u16 gap; + __u32 ctsn = ntohl(sack->cum_tsn_ack); + + if (TSN_lte(tsn, ctsn)) + goto pass; + + /* 3.3.4 Selective Acknowledgement (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; + gap = tsn - ctsn; + for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) { + if (TSN_lte(ntohs(frags[i].gab.start), gap) && + TSN_lte(gap, 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. */ +static 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); + } +} |