v4.19.13 snapshot.
diff --git a/net/sctp/associola.c b/net/sctp/associola.c
new file mode 100644
index 0000000..914750b
--- /dev/null
+++ b/net/sctp/associola.c
@@ -0,0 +1,1742 @@
+/* SCTP kernel implementation
+ * (C) Copyright IBM Corp. 2001, 2004
+ * Copyright (c) 1999-2000 Cisco, Inc.
+ * Copyright (c) 1999-2001 Motorola, Inc.
+ * Copyright (c) 2001 Intel Corp.
+ * Copyright (c) 2001 La Monte H.P. Yarroll
+ *
+ * This file is part of the SCTP kernel implementation
+ *
+ * This module provides the abstraction for an SCTP association.
+ *
+ * This SCTP implementation is free software;
+ * you can redistribute it and/or modify it under the terms of
+ * the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This SCTP implementation is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied
+ * ************************
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU CC; see the file COPYING. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Please send any bug reports or fixes you make to the
+ * email address(es):
+ * lksctp developers <linux-sctp@vger.kernel.org>
+ *
+ * Written or modified by:
+ * La Monte H.P. Yarroll <piggy@acm.org>
+ * Karl Knutson <karl@athena.chicago.il.us>
+ * Jon Grimm <jgrimm@us.ibm.com>
+ * Xingang Guo <xingang.guo@intel.com>
+ * Hui Huang <hui.huang@nokia.com>
+ * Sridhar Samudrala <sri@us.ibm.com>
+ * Daisy Chang <daisyc@us.ibm.com>
+ * Ryan Layer <rmlayer@us.ibm.com>
+ * Kevin Gao <kevin.gao@intel.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/fcntl.h>
+#include <linux/poll.h>
+#include <linux/init.h>
+
+#include <linux/slab.h>
+#include <linux/in.h>
+#include <net/ipv6.h>
+#include <net/sctp/sctp.h>
+#include <net/sctp/sm.h>
+
+/* Forward declarations for internal functions. */
+static void sctp_select_active_and_retran_path(struct sctp_association *asoc);
+static void sctp_assoc_bh_rcv(struct work_struct *work);
+static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc);
+static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc);
+
+/* 1st Level Abstractions. */
+
+/* Initialize a new association from provided memory. */
+static struct sctp_association *sctp_association_init(
+ struct sctp_association *asoc,
+ const struct sctp_endpoint *ep,
+ const struct sock *sk,
+ enum sctp_scope scope, gfp_t gfp)
+{
+ struct net *net = sock_net(sk);
+ struct sctp_sock *sp;
+ struct sctp_paramhdr *p;
+ int i;
+
+ /* Retrieve the SCTP per socket area. */
+ sp = sctp_sk((struct sock *)sk);
+
+ /* Discarding const is appropriate here. */
+ asoc->ep = (struct sctp_endpoint *)ep;
+ asoc->base.sk = (struct sock *)sk;
+
+ sctp_endpoint_hold(asoc->ep);
+ sock_hold(asoc->base.sk);
+
+ /* Initialize the common base substructure. */
+ asoc->base.type = SCTP_EP_TYPE_ASSOCIATION;
+
+ /* Initialize the object handling fields. */
+ refcount_set(&asoc->base.refcnt, 1);
+
+ /* Initialize the bind addr area. */
+ sctp_bind_addr_init(&asoc->base.bind_addr, ep->base.bind_addr.port);
+
+ asoc->state = SCTP_STATE_CLOSED;
+ asoc->cookie_life = ms_to_ktime(sp->assocparams.sasoc_cookie_life);
+ asoc->user_frag = sp->user_frag;
+
+ /* Set the association max_retrans and RTO values from the
+ * socket values.
+ */
+ asoc->max_retrans = sp->assocparams.sasoc_asocmaxrxt;
+ asoc->pf_retrans = net->sctp.pf_retrans;
+
+ asoc->rto_initial = msecs_to_jiffies(sp->rtoinfo.srto_initial);
+ asoc->rto_max = msecs_to_jiffies(sp->rtoinfo.srto_max);
+ asoc->rto_min = msecs_to_jiffies(sp->rtoinfo.srto_min);
+
+ /* Initialize the association's heartbeat interval based on the
+ * sock configured value.
+ */
+ asoc->hbinterval = msecs_to_jiffies(sp->hbinterval);
+
+ /* Initialize path max retrans value. */
+ asoc->pathmaxrxt = sp->pathmaxrxt;
+
+ asoc->flowlabel = sp->flowlabel;
+ asoc->dscp = sp->dscp;
+
+ /* Set association default SACK delay */
+ asoc->sackdelay = msecs_to_jiffies(sp->sackdelay);
+ asoc->sackfreq = sp->sackfreq;
+
+ /* Set the association default flags controlling
+ * Heartbeat, SACK delay, and Path MTU Discovery.
+ */
+ asoc->param_flags = sp->param_flags;
+
+ /* Initialize the maximum number of new data packets that can be sent
+ * in a burst.
+ */
+ asoc->max_burst = sp->max_burst;
+
+ /* initialize association timers */
+ asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] = asoc->rto_initial;
+ asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] = asoc->rto_initial;
+ asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = asoc->rto_initial;
+
+ /* sctpimpguide Section 2.12.2
+ * If the 'T5-shutdown-guard' timer is used, it SHOULD be set to the
+ * recommended value of 5 times 'RTO.Max'.
+ */
+ asoc->timeouts[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]
+ = 5 * asoc->rto_max;
+
+ asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay;
+ asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] = sp->autoclose * HZ;
+
+ /* Initializes the timers */
+ for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i)
+ timer_setup(&asoc->timers[i], sctp_timer_events[i], 0);
+
+ /* Pull default initialization values from the sock options.
+ * Note: This assumes that the values have already been
+ * validated in the sock.
+ */
+ asoc->c.sinit_max_instreams = sp->initmsg.sinit_max_instreams;
+ asoc->c.sinit_num_ostreams = sp->initmsg.sinit_num_ostreams;
+ asoc->max_init_attempts = sp->initmsg.sinit_max_attempts;
+
+ asoc->max_init_timeo =
+ msecs_to_jiffies(sp->initmsg.sinit_max_init_timeo);
+
+ /* Set the local window size for receive.
+ * This is also the rcvbuf space per association.
+ * RFC 6 - A SCTP receiver MUST be able to receive a minimum of
+ * 1500 bytes in one SCTP packet.
+ */
+ if ((sk->sk_rcvbuf/2) < SCTP_DEFAULT_MINWINDOW)
+ asoc->rwnd = SCTP_DEFAULT_MINWINDOW;
+ else
+ asoc->rwnd = sk->sk_rcvbuf/2;
+
+ asoc->a_rwnd = asoc->rwnd;
+
+ /* Use my own max window until I learn something better. */
+ asoc->peer.rwnd = SCTP_DEFAULT_MAXWINDOW;
+
+ /* Initialize the receive memory counter */
+ atomic_set(&asoc->rmem_alloc, 0);
+
+ init_waitqueue_head(&asoc->wait);
+
+ asoc->c.my_vtag = sctp_generate_tag(ep);
+ asoc->c.my_port = ep->base.bind_addr.port;
+
+ asoc->c.initial_tsn = sctp_generate_tsn(ep);
+
+ asoc->next_tsn = asoc->c.initial_tsn;
+
+ asoc->ctsn_ack_point = asoc->next_tsn - 1;
+ asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
+ asoc->highest_sacked = asoc->ctsn_ack_point;
+ asoc->last_cwr_tsn = asoc->ctsn_ack_point;
+
+ /* ADDIP Section 4.1 Asconf Chunk Procedures
+ *
+ * When an endpoint has an ASCONF signaled change to be sent to the
+ * remote endpoint it should do the following:
+ * ...
+ * A2) a serial number should be assigned to the chunk. The serial
+ * number SHOULD be a monotonically increasing number. The serial
+ * numbers SHOULD be initialized at the start of the
+ * association to the same value as the initial TSN.
+ */
+ asoc->addip_serial = asoc->c.initial_tsn;
+ asoc->strreset_outseq = asoc->c.initial_tsn;
+
+ INIT_LIST_HEAD(&asoc->addip_chunk_list);
+ INIT_LIST_HEAD(&asoc->asconf_ack_list);
+
+ /* Make an empty list of remote transport addresses. */
+ INIT_LIST_HEAD(&asoc->peer.transport_addr_list);
+
+ /* RFC 2960 5.1 Normal Establishment of an Association
+ *
+ * After the reception of the first data chunk in an
+ * association the endpoint must immediately respond with a
+ * sack to acknowledge the data chunk. Subsequent
+ * acknowledgements should be done as described in Section
+ * 6.2.
+ *
+ * [We implement this by telling a new association that it
+ * already received one packet.]
+ */
+ asoc->peer.sack_needed = 1;
+ asoc->peer.sack_generation = 1;
+
+ /* Assume that the peer will tell us if he recognizes ASCONF
+ * as part of INIT exchange.
+ * The sctp_addip_noauth option is there for backward compatibility
+ * and will revert old behavior.
+ */
+ if (net->sctp.addip_noauth)
+ asoc->peer.asconf_capable = 1;
+
+ /* Create an input queue. */
+ sctp_inq_init(&asoc->base.inqueue);
+ sctp_inq_set_th_handler(&asoc->base.inqueue, sctp_assoc_bh_rcv);
+
+ /* Create an output queue. */
+ sctp_outq_init(asoc, &asoc->outqueue);
+
+ if (!sctp_ulpq_init(&asoc->ulpq, asoc))
+ goto fail_init;
+
+ if (sctp_stream_init(&asoc->stream, asoc->c.sinit_num_ostreams,
+ 0, gfp))
+ goto fail_init;
+
+ /* Initialize default path MTU. */
+ asoc->pathmtu = sp->pathmtu;
+ sctp_assoc_update_frag_point(asoc);
+
+ /* Assume that peer would support both address types unless we are
+ * told otherwise.
+ */
+ asoc->peer.ipv4_address = 1;
+ if (asoc->base.sk->sk_family == PF_INET6)
+ asoc->peer.ipv6_address = 1;
+ INIT_LIST_HEAD(&asoc->asocs);
+
+ asoc->default_stream = sp->default_stream;
+ asoc->default_ppid = sp->default_ppid;
+ asoc->default_flags = sp->default_flags;
+ asoc->default_context = sp->default_context;
+ asoc->default_timetolive = sp->default_timetolive;
+ asoc->default_rcv_context = sp->default_rcv_context;
+
+ /* AUTH related initializations */
+ INIT_LIST_HEAD(&asoc->endpoint_shared_keys);
+ if (sctp_auth_asoc_copy_shkeys(ep, asoc, gfp))
+ goto stream_free;
+
+ asoc->active_key_id = ep->active_key_id;
+ asoc->prsctp_enable = ep->prsctp_enable;
+ asoc->reconf_enable = ep->reconf_enable;
+ asoc->strreset_enable = ep->strreset_enable;
+
+ /* Save the hmacs and chunks list into this association */
+ if (ep->auth_hmacs_list)
+ memcpy(asoc->c.auth_hmacs, ep->auth_hmacs_list,
+ ntohs(ep->auth_hmacs_list->param_hdr.length));
+ if (ep->auth_chunk_list)
+ memcpy(asoc->c.auth_chunks, ep->auth_chunk_list,
+ ntohs(ep->auth_chunk_list->param_hdr.length));
+
+ /* Get the AUTH random number for this association */
+ p = (struct sctp_paramhdr *)asoc->c.auth_random;
+ p->type = SCTP_PARAM_RANDOM;
+ p->length = htons(sizeof(*p) + SCTP_AUTH_RANDOM_LENGTH);
+ get_random_bytes(p+1, SCTP_AUTH_RANDOM_LENGTH);
+
+ return asoc;
+
+stream_free:
+ sctp_stream_free(&asoc->stream);
+fail_init:
+ sock_put(asoc->base.sk);
+ sctp_endpoint_put(asoc->ep);
+ return NULL;
+}
+
+/* Allocate and initialize a new association */
+struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep,
+ const struct sock *sk,
+ enum sctp_scope scope, gfp_t gfp)
+{
+ struct sctp_association *asoc;
+
+ asoc = kzalloc(sizeof(*asoc), gfp);
+ if (!asoc)
+ goto fail;
+
+ if (!sctp_association_init(asoc, ep, sk, scope, gfp))
+ goto fail_init;
+
+ SCTP_DBG_OBJCNT_INC(assoc);
+
+ pr_debug("Created asoc %p\n", asoc);
+
+ return asoc;
+
+fail_init:
+ kfree(asoc);
+fail:
+ return NULL;
+}
+
+/* Free this association if possible. There may still be users, so
+ * the actual deallocation may be delayed.
+ */
+void sctp_association_free(struct sctp_association *asoc)
+{
+ struct sock *sk = asoc->base.sk;
+ struct sctp_transport *transport;
+ struct list_head *pos, *temp;
+ int i;
+
+ /* Only real associations count against the endpoint, so
+ * don't bother for if this is a temporary association.
+ */
+ if (!list_empty(&asoc->asocs)) {
+ list_del(&asoc->asocs);
+
+ /* Decrement the backlog value for a TCP-style listening
+ * socket.
+ */
+ if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
+ sk->sk_ack_backlog--;
+ }
+
+ /* Mark as dead, so other users can know this structure is
+ * going away.
+ */
+ asoc->base.dead = true;
+
+ /* Dispose of any data lying around in the outqueue. */
+ sctp_outq_free(&asoc->outqueue);
+
+ /* Dispose of any pending messages for the upper layer. */
+ sctp_ulpq_free(&asoc->ulpq);
+
+ /* Dispose of any pending chunks on the inqueue. */
+ sctp_inq_free(&asoc->base.inqueue);
+
+ sctp_tsnmap_free(&asoc->peer.tsn_map);
+
+ /* Free stream information. */
+ sctp_stream_free(&asoc->stream);
+
+ if (asoc->strreset_chunk)
+ sctp_chunk_free(asoc->strreset_chunk);
+
+ /* Clean up the bound address list. */
+ sctp_bind_addr_free(&asoc->base.bind_addr);
+
+ /* Do we need to go through all of our timers and
+ * delete them? To be safe we will try to delete all, but we
+ * should be able to go through and make a guess based
+ * on our state.
+ */
+ for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
+ if (del_timer(&asoc->timers[i]))
+ sctp_association_put(asoc);
+ }
+
+ /* Free peer's cached cookie. */
+ kfree(asoc->peer.cookie);
+ kfree(asoc->peer.peer_random);
+ kfree(asoc->peer.peer_chunks);
+ kfree(asoc->peer.peer_hmacs);
+
+ /* Release the transport structures. */
+ list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
+ transport = list_entry(pos, struct sctp_transport, transports);
+ list_del_rcu(pos);
+ sctp_unhash_transport(transport);
+ sctp_transport_free(transport);
+ }
+
+ asoc->peer.transport_count = 0;
+
+ sctp_asconf_queue_teardown(asoc);
+
+ /* Free pending address space being deleted */
+ kfree(asoc->asconf_addr_del_pending);
+
+ /* AUTH - Free the endpoint shared keys */
+ sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
+
+ /* AUTH - Free the association shared key */
+ sctp_auth_key_put(asoc->asoc_shared_key);
+
+ sctp_association_put(asoc);
+}
+
+/* Cleanup and free up an association. */
+static void sctp_association_destroy(struct sctp_association *asoc)
+{
+ if (unlikely(!asoc->base.dead)) {
+ WARN(1, "Attempt to destroy undead association %p!\n", asoc);
+ return;
+ }
+
+ sctp_endpoint_put(asoc->ep);
+ sock_put(asoc->base.sk);
+
+ if (asoc->assoc_id != 0) {
+ spin_lock_bh(&sctp_assocs_id_lock);
+ idr_remove(&sctp_assocs_id, asoc->assoc_id);
+ spin_unlock_bh(&sctp_assocs_id_lock);
+ }
+
+ WARN_ON(atomic_read(&asoc->rmem_alloc));
+
+ kfree_rcu(asoc, rcu);
+ SCTP_DBG_OBJCNT_DEC(assoc);
+}
+
+/* Change the primary destination address for the peer. */
+void sctp_assoc_set_primary(struct sctp_association *asoc,
+ struct sctp_transport *transport)
+{
+ int changeover = 0;
+
+ /* it's a changeover only if we already have a primary path
+ * that we are changing
+ */
+ if (asoc->peer.primary_path != NULL &&
+ asoc->peer.primary_path != transport)
+ changeover = 1 ;
+
+ asoc->peer.primary_path = transport;
+
+ /* Set a default msg_name for events. */
+ memcpy(&asoc->peer.primary_addr, &transport->ipaddr,
+ sizeof(union sctp_addr));
+
+ /* If the primary path is changing, assume that the
+ * user wants to use this new path.
+ */
+ if ((transport->state == SCTP_ACTIVE) ||
+ (transport->state == SCTP_UNKNOWN))
+ asoc->peer.active_path = transport;
+
+ /*
+ * SFR-CACC algorithm:
+ * Upon the receipt of a request to change the primary
+ * destination address, on the data structure for the new
+ * primary destination, the sender MUST do the following:
+ *
+ * 1) If CHANGEOVER_ACTIVE is set, then there was a switch
+ * to this destination address earlier. The sender MUST set
+ * CYCLING_CHANGEOVER to indicate that this switch is a
+ * double switch to the same destination address.
+ *
+ * Really, only bother is we have data queued or outstanding on
+ * the association.
+ */
+ if (!asoc->outqueue.outstanding_bytes && !asoc->outqueue.out_qlen)
+ return;
+
+ if (transport->cacc.changeover_active)
+ transport->cacc.cycling_changeover = changeover;
+
+ /* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that
+ * a changeover has occurred.
+ */
+ transport->cacc.changeover_active = changeover;
+
+ /* 3) The sender MUST store the next TSN to be sent in
+ * next_tsn_at_change.
+ */
+ transport->cacc.next_tsn_at_change = asoc->next_tsn;
+}
+
+/* Remove a transport from an association. */
+void sctp_assoc_rm_peer(struct sctp_association *asoc,
+ struct sctp_transport *peer)
+{
+ struct sctp_transport *transport;
+ struct list_head *pos;
+ struct sctp_chunk *ch;
+
+ pr_debug("%s: association:%p addr:%pISpc\n",
+ __func__, asoc, &peer->ipaddr.sa);
+
+ /* If we are to remove the current retran_path, update it
+ * to the next peer before removing this peer from the list.
+ */
+ if (asoc->peer.retran_path == peer)
+ sctp_assoc_update_retran_path(asoc);
+
+ /* Remove this peer from the list. */
+ list_del_rcu(&peer->transports);
+ /* Remove this peer from the transport hashtable */
+ sctp_unhash_transport(peer);
+
+ /* Get the first transport of asoc. */
+ pos = asoc->peer.transport_addr_list.next;
+ transport = list_entry(pos, struct sctp_transport, transports);
+
+ /* Update any entries that match the peer to be deleted. */
+ if (asoc->peer.primary_path == peer)
+ sctp_assoc_set_primary(asoc, transport);
+ if (asoc->peer.active_path == peer)
+ asoc->peer.active_path = transport;
+ if (asoc->peer.retran_path == peer)
+ asoc->peer.retran_path = transport;
+ if (asoc->peer.last_data_from == peer)
+ asoc->peer.last_data_from = transport;
+
+ if (asoc->strreset_chunk &&
+ asoc->strreset_chunk->transport == peer) {
+ asoc->strreset_chunk->transport = transport;
+ sctp_transport_reset_reconf_timer(transport);
+ }
+
+ /* If we remove the transport an INIT was last sent to, set it to
+ * NULL. Combined with the update of the retran path above, this
+ * will cause the next INIT to be sent to the next available
+ * transport, maintaining the cycle.
+ */
+ if (asoc->init_last_sent_to == peer)
+ asoc->init_last_sent_to = NULL;
+
+ /* If we remove the transport an SHUTDOWN was last sent to, set it
+ * to NULL. Combined with the update of the retran path above, this
+ * will cause the next SHUTDOWN to be sent to the next available
+ * transport, maintaining the cycle.
+ */
+ if (asoc->shutdown_last_sent_to == peer)
+ asoc->shutdown_last_sent_to = NULL;
+
+ /* If we remove the transport an ASCONF was last sent to, set it to
+ * NULL.
+ */
+ if (asoc->addip_last_asconf &&
+ asoc->addip_last_asconf->transport == peer)
+ asoc->addip_last_asconf->transport = NULL;
+
+ /* If we have something on the transmitted list, we have to
+ * save it off. The best place is the active path.
+ */
+ if (!list_empty(&peer->transmitted)) {
+ struct sctp_transport *active = asoc->peer.active_path;
+
+ /* Reset the transport of each chunk on this list */
+ list_for_each_entry(ch, &peer->transmitted,
+ transmitted_list) {
+ ch->transport = NULL;
+ ch->rtt_in_progress = 0;
+ }
+
+ list_splice_tail_init(&peer->transmitted,
+ &active->transmitted);
+
+ /* Start a T3 timer here in case it wasn't running so
+ * that these migrated packets have a chance to get
+ * retransmitted.
+ */
+ if (!timer_pending(&active->T3_rtx_timer))
+ if (!mod_timer(&active->T3_rtx_timer,
+ jiffies + active->rto))
+ sctp_transport_hold(active);
+ }
+
+ list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list)
+ if (ch->transport == peer)
+ ch->transport = NULL;
+
+ asoc->peer.transport_count--;
+
+ sctp_transport_free(peer);
+}
+
+/* Add a transport address to an association. */
+struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
+ const union sctp_addr *addr,
+ const gfp_t gfp,
+ const int peer_state)
+{
+ struct net *net = sock_net(asoc->base.sk);
+ struct sctp_transport *peer;
+ struct sctp_sock *sp;
+ unsigned short port;
+
+ sp = sctp_sk(asoc->base.sk);
+
+ /* AF_INET and AF_INET6 share common port field. */
+ port = ntohs(addr->v4.sin_port);
+
+ pr_debug("%s: association:%p addr:%pISpc state:%d\n", __func__,
+ asoc, &addr->sa, peer_state);
+
+ /* Set the port if it has not been set yet. */
+ if (0 == asoc->peer.port)
+ asoc->peer.port = port;
+
+ /* Check to see if this is a duplicate. */
+ peer = sctp_assoc_lookup_paddr(asoc, addr);
+ if (peer) {
+ /* An UNKNOWN state is only set on transports added by
+ * user in sctp_connectx() call. Such transports should be
+ * considered CONFIRMED per RFC 4960, Section 5.4.
+ */
+ if (peer->state == SCTP_UNKNOWN) {
+ peer->state = SCTP_ACTIVE;
+ }
+ return peer;
+ }
+
+ peer = sctp_transport_new(net, addr, gfp);
+ if (!peer)
+ return NULL;
+
+ sctp_transport_set_owner(peer, asoc);
+
+ /* Initialize the peer's heartbeat interval based on the
+ * association configured value.
+ */
+ peer->hbinterval = asoc->hbinterval;
+
+ /* Set the path max_retrans. */
+ peer->pathmaxrxt = asoc->pathmaxrxt;
+
+ /* And the partial failure retrans threshold */
+ peer->pf_retrans = asoc->pf_retrans;
+
+ /* Initialize the peer's SACK delay timeout based on the
+ * association configured value.
+ */
+ peer->sackdelay = asoc->sackdelay;
+ peer->sackfreq = asoc->sackfreq;
+
+ if (addr->sa.sa_family == AF_INET6) {
+ __be32 info = addr->v6.sin6_flowinfo;
+
+ if (info) {
+ peer->flowlabel = ntohl(info & IPV6_FLOWLABEL_MASK);
+ peer->flowlabel |= SCTP_FLOWLABEL_SET_MASK;
+ } else {
+ peer->flowlabel = asoc->flowlabel;
+ }
+ }
+ peer->dscp = asoc->dscp;
+
+ /* Enable/disable heartbeat, SACK delay, and path MTU discovery
+ * based on association setting.
+ */
+ peer->param_flags = asoc->param_flags;
+
+ /* Initialize the pmtu of the transport. */
+ sctp_transport_route(peer, NULL, sp);
+
+ /* If this is the first transport addr on this association,
+ * initialize the association PMTU to the peer's PMTU.
+ * If not and the current association PMTU is higher than the new
+ * peer's PMTU, reset the association PMTU to the new peer's PMTU.
+ */
+ sctp_assoc_set_pmtu(asoc, asoc->pathmtu ?
+ min_t(int, peer->pathmtu, asoc->pathmtu) :
+ peer->pathmtu);
+
+ peer->pmtu_pending = 0;
+
+ /* The asoc->peer.port might not be meaningful yet, but
+ * initialize the packet structure anyway.
+ */
+ sctp_packet_init(&peer->packet, peer, asoc->base.bind_addr.port,
+ asoc->peer.port);
+
+ /* 7.2.1 Slow-Start
+ *
+ * o The initial cwnd before DATA transmission or after a sufficiently
+ * long idle period MUST be set to
+ * min(4*MTU, max(2*MTU, 4380 bytes))
+ *
+ * o The initial value of ssthresh MAY be arbitrarily high
+ * (for example, implementations MAY use the size of the
+ * receiver advertised window).
+ */
+ peer->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380));
+
+ /* At this point, we may not have the receiver's advertised window,
+ * so initialize ssthresh to the default value and it will be set
+ * later when we process the INIT.
+ */
+ peer->ssthresh = SCTP_DEFAULT_MAXWINDOW;
+
+ peer->partial_bytes_acked = 0;
+ peer->flight_size = 0;
+ peer->burst_limited = 0;
+
+ /* Set the transport's RTO.initial value */
+ peer->rto = asoc->rto_initial;
+ sctp_max_rto(asoc, peer);
+
+ /* Set the peer's active state. */
+ peer->state = peer_state;
+
+ /* Add this peer into the transport hashtable */
+ if (sctp_hash_transport(peer)) {
+ sctp_transport_free(peer);
+ return NULL;
+ }
+
+ /* Attach the remote transport to our asoc. */
+ list_add_tail_rcu(&peer->transports, &asoc->peer.transport_addr_list);
+ asoc->peer.transport_count++;
+
+ /* If we do not yet have a primary path, set one. */
+ if (!asoc->peer.primary_path) {
+ sctp_assoc_set_primary(asoc, peer);
+ asoc->peer.retran_path = peer;
+ }
+
+ if (asoc->peer.active_path == asoc->peer.retran_path &&
+ peer->state != SCTP_UNCONFIRMED) {
+ asoc->peer.retran_path = peer;
+ }
+
+ return peer;
+}
+
+/* Delete a transport address from an association. */
+void sctp_assoc_del_peer(struct sctp_association *asoc,
+ const union sctp_addr *addr)
+{
+ struct list_head *pos;
+ struct list_head *temp;
+ struct sctp_transport *transport;
+
+ list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
+ transport = list_entry(pos, struct sctp_transport, transports);
+ if (sctp_cmp_addr_exact(addr, &transport->ipaddr)) {
+ /* Do book keeping for removing the peer and free it. */
+ sctp_assoc_rm_peer(asoc, transport);
+ break;
+ }
+ }
+}
+
+/* Lookup a transport by address. */
+struct sctp_transport *sctp_assoc_lookup_paddr(
+ const struct sctp_association *asoc,
+ const union sctp_addr *address)
+{
+ struct sctp_transport *t;
+
+ /* Cycle through all transports searching for a peer address. */
+
+ list_for_each_entry(t, &asoc->peer.transport_addr_list,
+ transports) {
+ if (sctp_cmp_addr_exact(address, &t->ipaddr))
+ return t;
+ }
+
+ return NULL;
+}
+
+/* Remove all transports except a give one */
+void sctp_assoc_del_nonprimary_peers(struct sctp_association *asoc,
+ struct sctp_transport *primary)
+{
+ struct sctp_transport *temp;
+ struct sctp_transport *t;
+
+ list_for_each_entry_safe(t, temp, &asoc->peer.transport_addr_list,
+ transports) {
+ /* if the current transport is not the primary one, delete it */
+ if (t != primary)
+ sctp_assoc_rm_peer(asoc, t);
+ }
+}
+
+/* Engage in transport control operations.
+ * Mark the transport up or down and send a notification to the user.
+ * Select and update the new active and retran paths.
+ */
+void sctp_assoc_control_transport(struct sctp_association *asoc,
+ struct sctp_transport *transport,
+ enum sctp_transport_cmd command,
+ sctp_sn_error_t error)
+{
+ struct sctp_ulpevent *event;
+ struct sockaddr_storage addr;
+ int spc_state = 0;
+ bool ulp_notify = true;
+
+ /* Record the transition on the transport. */
+ switch (command) {
+ case SCTP_TRANSPORT_UP:
+ /* If we are moving from UNCONFIRMED state due
+ * to heartbeat success, report the SCTP_ADDR_CONFIRMED
+ * state to the user, otherwise report SCTP_ADDR_AVAILABLE.
+ */
+ if (SCTP_UNCONFIRMED == transport->state &&
+ SCTP_HEARTBEAT_SUCCESS == error)
+ spc_state = SCTP_ADDR_CONFIRMED;
+ else
+ spc_state = SCTP_ADDR_AVAILABLE;
+ /* Don't inform ULP about transition from PF to
+ * active state and set cwnd to 1 MTU, see SCTP
+ * Quick failover draft section 5.1, point 5
+ */
+ if (transport->state == SCTP_PF) {
+ ulp_notify = false;
+ transport->cwnd = asoc->pathmtu;
+ }
+ transport->state = SCTP_ACTIVE;
+ break;
+
+ case SCTP_TRANSPORT_DOWN:
+ /* If the transport was never confirmed, do not transition it
+ * to inactive state. Also, release the cached route since
+ * there may be a better route next time.
+ */
+ if (transport->state != SCTP_UNCONFIRMED)
+ transport->state = SCTP_INACTIVE;
+ else {
+ sctp_transport_dst_release(transport);
+ ulp_notify = false;
+ }
+
+ spc_state = SCTP_ADDR_UNREACHABLE;
+ break;
+
+ case SCTP_TRANSPORT_PF:
+ transport->state = SCTP_PF;
+ ulp_notify = false;
+ break;
+
+ default:
+ return;
+ }
+
+ /* Generate and send a SCTP_PEER_ADDR_CHANGE notification
+ * to the user.
+ */
+ if (ulp_notify) {
+ memset(&addr, 0, sizeof(struct sockaddr_storage));
+ memcpy(&addr, &transport->ipaddr,
+ transport->af_specific->sockaddr_len);
+
+ event = sctp_ulpevent_make_peer_addr_change(asoc, &addr,
+ 0, spc_state, error, GFP_ATOMIC);
+ if (event)
+ asoc->stream.si->enqueue_event(&asoc->ulpq, event);
+ }
+
+ /* Select new active and retran paths. */
+ sctp_select_active_and_retran_path(asoc);
+}
+
+/* Hold a reference to an association. */
+void sctp_association_hold(struct sctp_association *asoc)
+{
+ refcount_inc(&asoc->base.refcnt);
+}
+
+/* Release a reference to an association and cleanup
+ * if there are no more references.
+ */
+void sctp_association_put(struct sctp_association *asoc)
+{
+ if (refcount_dec_and_test(&asoc->base.refcnt))
+ sctp_association_destroy(asoc);
+}
+
+/* Allocate the next TSN, Transmission Sequence Number, for the given
+ * association.
+ */
+__u32 sctp_association_get_next_tsn(struct sctp_association *asoc)
+{
+ /* From Section 1.6 Serial Number Arithmetic:
+ * Transmission Sequence Numbers wrap around when they reach
+ * 2**32 - 1. That is, the next TSN a DATA chunk MUST use
+ * after transmitting TSN = 2*32 - 1 is TSN = 0.
+ */
+ __u32 retval = asoc->next_tsn;
+ asoc->next_tsn++;
+ asoc->unack_data++;
+
+ return retval;
+}
+
+/* Compare two addresses to see if they match. Wildcard addresses
+ * only match themselves.
+ */
+int sctp_cmp_addr_exact(const union sctp_addr *ss1,
+ const union sctp_addr *ss2)
+{
+ struct sctp_af *af;
+
+ af = sctp_get_af_specific(ss1->sa.sa_family);
+ if (unlikely(!af))
+ return 0;
+
+ return af->cmp_addr(ss1, ss2);
+}
+
+/* Return an ecne chunk to get prepended to a packet.
+ * Note: We are sly and return a shared, prealloced chunk. FIXME:
+ * No we don't, but we could/should.
+ */
+struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc)
+{
+ if (!asoc->need_ecne)
+ return NULL;
+
+ /* Send ECNE if needed.
+ * Not being able to allocate a chunk here is not deadly.
+ */
+ return sctp_make_ecne(asoc, asoc->last_ecne_tsn);
+}
+
+/*
+ * Find which transport this TSN was sent on.
+ */
+struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *asoc,
+ __u32 tsn)
+{
+ struct sctp_transport *active;
+ struct sctp_transport *match;
+ struct sctp_transport *transport;
+ struct sctp_chunk *chunk;
+ __be32 key = htonl(tsn);
+
+ match = NULL;
+
+ /*
+ * FIXME: In general, find a more efficient data structure for
+ * searching.
+ */
+
+ /*
+ * The general strategy is to search each transport's transmitted
+ * list. Return which transport this TSN lives on.
+ *
+ * Let's be hopeful and check the active_path first.
+ * Another optimization would be to know if there is only one
+ * outbound path and not have to look for the TSN at all.
+ *
+ */
+
+ active = asoc->peer.active_path;
+
+ list_for_each_entry(chunk, &active->transmitted,
+ transmitted_list) {
+
+ if (key == chunk->subh.data_hdr->tsn) {
+ match = active;
+ goto out;
+ }
+ }
+
+ /* If not found, go search all the other transports. */
+ list_for_each_entry(transport, &asoc->peer.transport_addr_list,
+ transports) {
+
+ if (transport == active)
+ continue;
+ list_for_each_entry(chunk, &transport->transmitted,
+ transmitted_list) {
+ if (key == chunk->subh.data_hdr->tsn) {
+ match = transport;
+ goto out;
+ }
+ }
+ }
+out:
+ return match;
+}
+
+/* Do delayed input processing. This is scheduled by sctp_rcv(). */
+static void sctp_assoc_bh_rcv(struct work_struct *work)
+{
+ struct sctp_association *asoc =
+ container_of(work, struct sctp_association,
+ base.inqueue.immediate);
+ struct net *net = sock_net(asoc->base.sk);
+ union sctp_subtype subtype;
+ struct sctp_endpoint *ep;
+ struct sctp_chunk *chunk;
+ struct sctp_inq *inqueue;
+ int first_time = 1; /* is this the first time through the loop */
+ int error = 0;
+ int state;
+
+ /* The association should be held so we should be safe. */
+ ep = asoc->ep;
+
+ inqueue = &asoc->base.inqueue;
+ sctp_association_hold(asoc);
+ while (NULL != (chunk = sctp_inq_pop(inqueue))) {
+ state = asoc->state;
+ subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
+
+ /* If the first chunk in the packet is AUTH, do special
+ * processing specified in Section 6.3 of SCTP-AUTH spec
+ */
+ if (first_time && subtype.chunk == SCTP_CID_AUTH) {
+ struct sctp_chunkhdr *next_hdr;
+
+ next_hdr = sctp_inq_peek(inqueue);
+ if (!next_hdr)
+ goto normal;
+
+ /* If the next chunk is COOKIE-ECHO, skip the AUTH
+ * chunk while saving a pointer to it so we can do
+ * Authentication later (during cookie-echo
+ * processing).
+ */
+ if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
+ chunk->auth_chunk = skb_clone(chunk->skb,
+ GFP_ATOMIC);
+ chunk->auth = 1;
+ continue;
+ }
+ }
+
+normal:
+ /* SCTP-AUTH, Section 6.3:
+ * The receiver has a list of chunk types which it expects
+ * to be received only after an AUTH-chunk. This list has
+ * been sent to the peer during the association setup. It
+ * MUST silently discard these chunks if they are not placed
+ * after an AUTH chunk in the packet.
+ */
+ if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
+ continue;
+
+ /* Remember where the last DATA chunk came from so we
+ * know where to send the SACK.
+ */
+ if (sctp_chunk_is_data(chunk))
+ asoc->peer.last_data_from = chunk->transport;
+ else {
+ SCTP_INC_STATS(net, SCTP_MIB_INCTRLCHUNKS);
+ asoc->stats.ictrlchunks++;
+ if (chunk->chunk_hdr->type == SCTP_CID_SACK)
+ asoc->stats.isacks++;
+ }
+
+ if (chunk->transport)
+ chunk->transport->last_time_heard = ktime_get();
+
+ /* Run through the state machine. */
+ error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype,
+ state, ep, asoc, chunk, GFP_ATOMIC);
+
+ /* Check to see if the association is freed in response to
+ * the incoming chunk. If so, get out of the while loop.
+ */
+ if (asoc->base.dead)
+ break;
+
+ /* If there is an error on chunk, discard this packet. */
+ if (error && chunk)
+ chunk->pdiscard = 1;
+
+ if (first_time)
+ first_time = 0;
+ }
+ sctp_association_put(asoc);
+}
+
+/* This routine moves an association from its old sk to a new sk. */
+void sctp_assoc_migrate(struct sctp_association *assoc, struct sock *newsk)
+{
+ struct sctp_sock *newsp = sctp_sk(newsk);
+ struct sock *oldsk = assoc->base.sk;
+
+ /* Delete the association from the old endpoint's list of
+ * associations.
+ */
+ list_del_init(&assoc->asocs);
+
+ /* Decrement the backlog value for a TCP-style socket. */
+ if (sctp_style(oldsk, TCP))
+ oldsk->sk_ack_backlog--;
+
+ /* Release references to the old endpoint and the sock. */
+ sctp_endpoint_put(assoc->ep);
+ sock_put(assoc->base.sk);
+
+ /* Get a reference to the new endpoint. */
+ assoc->ep = newsp->ep;
+ sctp_endpoint_hold(assoc->ep);
+
+ /* Get a reference to the new sock. */
+ assoc->base.sk = newsk;
+ sock_hold(assoc->base.sk);
+
+ /* Add the association to the new endpoint's list of associations. */
+ sctp_endpoint_add_asoc(newsp->ep, assoc);
+}
+
+/* Update an association (possibly from unexpected COOKIE-ECHO processing). */
+int sctp_assoc_update(struct sctp_association *asoc,
+ struct sctp_association *new)
+{
+ struct sctp_transport *trans;
+ struct list_head *pos, *temp;
+
+ /* Copy in new parameters of peer. */
+ asoc->c = new->c;
+ asoc->peer.rwnd = new->peer.rwnd;
+ asoc->peer.sack_needed = new->peer.sack_needed;
+ asoc->peer.auth_capable = new->peer.auth_capable;
+ asoc->peer.i = new->peer.i;
+
+ if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
+ asoc->peer.i.initial_tsn, GFP_ATOMIC))
+ return -ENOMEM;
+
+ /* Remove any peer addresses not present in the new association. */
+ list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
+ trans = list_entry(pos, struct sctp_transport, transports);
+ if (!sctp_assoc_lookup_paddr(new, &trans->ipaddr)) {
+ sctp_assoc_rm_peer(asoc, trans);
+ continue;
+ }
+
+ if (asoc->state >= SCTP_STATE_ESTABLISHED)
+ sctp_transport_reset(trans);
+ }
+
+ /* If the case is A (association restart), use
+ * initial_tsn as next_tsn. If the case is B, use
+ * current next_tsn in case data sent to peer
+ * has been discarded and needs retransmission.
+ */
+ if (asoc->state >= SCTP_STATE_ESTABLISHED) {
+ asoc->next_tsn = new->next_tsn;
+ asoc->ctsn_ack_point = new->ctsn_ack_point;
+ asoc->adv_peer_ack_point = new->adv_peer_ack_point;
+
+ /* Reinitialize SSN for both local streams
+ * and peer's streams.
+ */
+ sctp_stream_clear(&asoc->stream);
+
+ /* Flush the ULP reassembly and ordered queue.
+ * Any data there will now be stale and will
+ * cause problems.
+ */
+ sctp_ulpq_flush(&asoc->ulpq);
+
+ /* reset the overall association error count so
+ * that the restarted association doesn't get torn
+ * down on the next retransmission timer.
+ */
+ asoc->overall_error_count = 0;
+
+ } else {
+ /* Add any peer addresses from the new association. */
+ list_for_each_entry(trans, &new->peer.transport_addr_list,
+ transports)
+ if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr) &&
+ !sctp_assoc_add_peer(asoc, &trans->ipaddr,
+ GFP_ATOMIC, trans->state))
+ return -ENOMEM;
+
+ asoc->ctsn_ack_point = asoc->next_tsn - 1;
+ asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
+
+ if (sctp_state(asoc, COOKIE_WAIT))
+ sctp_stream_update(&asoc->stream, &new->stream);
+
+ /* get a new assoc id if we don't have one yet. */
+ if (sctp_assoc_set_id(asoc, GFP_ATOMIC))
+ return -ENOMEM;
+ }
+
+ /* SCTP-AUTH: Save the peer parameters from the new associations
+ * and also move the association shared keys over
+ */
+ kfree(asoc->peer.peer_random);
+ asoc->peer.peer_random = new->peer.peer_random;
+ new->peer.peer_random = NULL;
+
+ kfree(asoc->peer.peer_chunks);
+ asoc->peer.peer_chunks = new->peer.peer_chunks;
+ new->peer.peer_chunks = NULL;
+
+ kfree(asoc->peer.peer_hmacs);
+ asoc->peer.peer_hmacs = new->peer.peer_hmacs;
+ new->peer.peer_hmacs = NULL;
+
+ return sctp_auth_asoc_init_active_key(asoc, GFP_ATOMIC);
+}
+
+/* Update the retran path for sending a retransmitted packet.
+ * See also RFC4960, 6.4. Multi-Homed SCTP Endpoints:
+ *
+ * When there is outbound data to send and the primary path
+ * becomes inactive (e.g., due to failures), or where the
+ * SCTP user explicitly requests to send data to an
+ * inactive destination transport address, before reporting
+ * an error to its ULP, the SCTP endpoint should try to send
+ * the data to an alternate active destination transport
+ * address if one exists.
+ *
+ * When retransmitting data that timed out, if the endpoint
+ * is multihomed, it should consider each source-destination
+ * address pair in its retransmission selection policy.
+ * When retransmitting timed-out data, the endpoint should
+ * attempt to pick the most divergent source-destination
+ * pair from the original source-destination pair to which
+ * the packet was transmitted.
+ *
+ * Note: Rules for picking the most divergent source-destination
+ * pair are an implementation decision and are not specified
+ * within this document.
+ *
+ * Our basic strategy is to round-robin transports in priorities
+ * according to sctp_trans_score() e.g., if no such
+ * transport with state SCTP_ACTIVE exists, round-robin through
+ * SCTP_UNKNOWN, etc. You get the picture.
+ */
+static u8 sctp_trans_score(const struct sctp_transport *trans)
+{
+ switch (trans->state) {
+ case SCTP_ACTIVE:
+ return 3; /* best case */
+ case SCTP_UNKNOWN:
+ return 2;
+ case SCTP_PF:
+ return 1;
+ default: /* case SCTP_INACTIVE */
+ return 0; /* worst case */
+ }
+}
+
+static struct sctp_transport *sctp_trans_elect_tie(struct sctp_transport *trans1,
+ struct sctp_transport *trans2)
+{
+ if (trans1->error_count > trans2->error_count) {
+ return trans2;
+ } else if (trans1->error_count == trans2->error_count &&
+ ktime_after(trans2->last_time_heard,
+ trans1->last_time_heard)) {
+ return trans2;
+ } else {
+ return trans1;
+ }
+}
+
+static struct sctp_transport *sctp_trans_elect_best(struct sctp_transport *curr,
+ struct sctp_transport *best)
+{
+ u8 score_curr, score_best;
+
+ if (best == NULL || curr == best)
+ return curr;
+
+ score_curr = sctp_trans_score(curr);
+ score_best = sctp_trans_score(best);
+
+ /* First, try a score-based selection if both transport states
+ * differ. If we're in a tie, lets try to make a more clever
+ * decision here based on error counts and last time heard.
+ */
+ if (score_curr > score_best)
+ return curr;
+ else if (score_curr == score_best)
+ return sctp_trans_elect_tie(best, curr);
+ else
+ return best;
+}
+
+void sctp_assoc_update_retran_path(struct sctp_association *asoc)
+{
+ struct sctp_transport *trans = asoc->peer.retran_path;
+ struct sctp_transport *trans_next = NULL;
+
+ /* We're done as we only have the one and only path. */
+ if (asoc->peer.transport_count == 1)
+ return;
+ /* If active_path and retran_path are the same and active,
+ * then this is the only active path. Use it.
+ */
+ if (asoc->peer.active_path == asoc->peer.retran_path &&
+ asoc->peer.active_path->state == SCTP_ACTIVE)
+ return;
+
+ /* Iterate from retran_path's successor back to retran_path. */
+ for (trans = list_next_entry(trans, transports); 1;
+ trans = list_next_entry(trans, transports)) {
+ /* Manually skip the head element. */
+ if (&trans->transports == &asoc->peer.transport_addr_list)
+ continue;
+ if (trans->state == SCTP_UNCONFIRMED)
+ continue;
+ trans_next = sctp_trans_elect_best(trans, trans_next);
+ /* Active is good enough for immediate return. */
+ if (trans_next->state == SCTP_ACTIVE)
+ break;
+ /* We've reached the end, time to update path. */
+ if (trans == asoc->peer.retran_path)
+ break;
+ }
+
+ asoc->peer.retran_path = trans_next;
+
+ pr_debug("%s: association:%p updated new path to addr:%pISpc\n",
+ __func__, asoc, &asoc->peer.retran_path->ipaddr.sa);
+}
+
+static void sctp_select_active_and_retran_path(struct sctp_association *asoc)
+{
+ struct sctp_transport *trans, *trans_pri = NULL, *trans_sec = NULL;
+ struct sctp_transport *trans_pf = NULL;
+
+ /* Look for the two most recently used active transports. */
+ list_for_each_entry(trans, &asoc->peer.transport_addr_list,
+ transports) {
+ /* Skip uninteresting transports. */
+ if (trans->state == SCTP_INACTIVE ||
+ trans->state == SCTP_UNCONFIRMED)
+ continue;
+ /* Keep track of the best PF transport from our
+ * list in case we don't find an active one.
+ */
+ if (trans->state == SCTP_PF) {
+ trans_pf = sctp_trans_elect_best(trans, trans_pf);
+ continue;
+ }
+ /* For active transports, pick the most recent ones. */
+ if (trans_pri == NULL ||
+ ktime_after(trans->last_time_heard,
+ trans_pri->last_time_heard)) {
+ trans_sec = trans_pri;
+ trans_pri = trans;
+ } else if (trans_sec == NULL ||
+ ktime_after(trans->last_time_heard,
+ trans_sec->last_time_heard)) {
+ trans_sec = trans;
+ }
+ }
+
+ /* RFC 2960 6.4 Multi-Homed SCTP Endpoints
+ *
+ * By default, an endpoint should always transmit to the primary
+ * path, unless the SCTP user explicitly specifies the
+ * destination transport address (and possibly source transport
+ * address) to use. [If the primary is active but not most recent,
+ * bump the most recently used transport.]
+ */
+ if ((asoc->peer.primary_path->state == SCTP_ACTIVE ||
+ asoc->peer.primary_path->state == SCTP_UNKNOWN) &&
+ asoc->peer.primary_path != trans_pri) {
+ trans_sec = trans_pri;
+ trans_pri = asoc->peer.primary_path;
+ }
+
+ /* We did not find anything useful for a possible retransmission
+ * path; either primary path that we found is the the same as
+ * the current one, or we didn't generally find an active one.
+ */
+ if (trans_sec == NULL)
+ trans_sec = trans_pri;
+
+ /* If we failed to find a usable transport, just camp on the
+ * active or pick a PF iff it's the better choice.
+ */
+ if (trans_pri == NULL) {
+ trans_pri = sctp_trans_elect_best(asoc->peer.active_path, trans_pf);
+ trans_sec = trans_pri;
+ }
+
+ /* Set the active and retran transports. */
+ asoc->peer.active_path = trans_pri;
+ asoc->peer.retran_path = trans_sec;
+}
+
+struct sctp_transport *
+sctp_assoc_choose_alter_transport(struct sctp_association *asoc,
+ struct sctp_transport *last_sent_to)
+{
+ /* If this is the first time packet is sent, use the active path,
+ * else use the retran path. If the last packet was sent over the
+ * retran path, update the retran path and use it.
+ */
+ if (last_sent_to == NULL) {
+ return asoc->peer.active_path;
+ } else {
+ if (last_sent_to == asoc->peer.retran_path)
+ sctp_assoc_update_retran_path(asoc);
+
+ return asoc->peer.retran_path;
+ }
+}
+
+void sctp_assoc_update_frag_point(struct sctp_association *asoc)
+{
+ int frag = sctp_mtu_payload(sctp_sk(asoc->base.sk), asoc->pathmtu,
+ sctp_datachk_len(&asoc->stream));
+
+ if (asoc->user_frag)
+ frag = min_t(int, frag, asoc->user_frag);
+
+ frag = min_t(int, frag, SCTP_MAX_CHUNK_LEN -
+ sctp_datachk_len(&asoc->stream));
+
+ asoc->frag_point = SCTP_TRUNC4(frag);
+}
+
+void sctp_assoc_set_pmtu(struct sctp_association *asoc, __u32 pmtu)
+{
+ if (asoc->pathmtu != pmtu) {
+ asoc->pathmtu = pmtu;
+ sctp_assoc_update_frag_point(asoc);
+ }
+
+ pr_debug("%s: asoc:%p, pmtu:%d, frag_point:%d\n", __func__, asoc,
+ asoc->pathmtu, asoc->frag_point);
+}
+
+/* Update the association's pmtu and frag_point by going through all the
+ * transports. This routine is called when a transport's PMTU has changed.
+ */
+void sctp_assoc_sync_pmtu(struct sctp_association *asoc)
+{
+ struct sctp_transport *t;
+ __u32 pmtu = 0;
+
+ if (!asoc)
+ return;
+
+ /* Get the lowest pmtu of all the transports. */
+ list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
+ if (t->pmtu_pending && t->dst) {
+ sctp_transport_update_pmtu(t,
+ atomic_read(&t->mtu_info));
+ t->pmtu_pending = 0;
+ }
+ if (!pmtu || (t->pathmtu < pmtu))
+ pmtu = t->pathmtu;
+ }
+
+ sctp_assoc_set_pmtu(asoc, pmtu);
+}
+
+/* Should we send a SACK to update our peer? */
+static inline bool sctp_peer_needs_update(struct sctp_association *asoc)
+{
+ struct net *net = sock_net(asoc->base.sk);
+ switch (asoc->state) {
+ case SCTP_STATE_ESTABLISHED:
+ case SCTP_STATE_SHUTDOWN_PENDING:
+ case SCTP_STATE_SHUTDOWN_RECEIVED:
+ case SCTP_STATE_SHUTDOWN_SENT:
+ if ((asoc->rwnd > asoc->a_rwnd) &&
+ ((asoc->rwnd - asoc->a_rwnd) >= max_t(__u32,
+ (asoc->base.sk->sk_rcvbuf >> net->sctp.rwnd_upd_shift),
+ asoc->pathmtu)))
+ return true;
+ break;
+ default:
+ break;
+ }
+ return false;
+}
+
+/* Increase asoc's rwnd by len and send any window update SACK if needed. */
+void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned int len)
+{
+ struct sctp_chunk *sack;
+ struct timer_list *timer;
+
+ if (asoc->rwnd_over) {
+ if (asoc->rwnd_over >= len) {
+ asoc->rwnd_over -= len;
+ } else {
+ asoc->rwnd += (len - asoc->rwnd_over);
+ asoc->rwnd_over = 0;
+ }
+ } else {
+ asoc->rwnd += len;
+ }
+
+ /* If we had window pressure, start recovering it
+ * once our rwnd had reached the accumulated pressure
+ * threshold. The idea is to recover slowly, but up
+ * to the initial advertised window.
+ */
+ if (asoc->rwnd_press) {
+ int change = min(asoc->pathmtu, asoc->rwnd_press);
+ asoc->rwnd += change;
+ asoc->rwnd_press -= change;
+ }
+
+ pr_debug("%s: asoc:%p rwnd increased by %d to (%u, %u) - %u\n",
+ __func__, asoc, len, asoc->rwnd, asoc->rwnd_over,
+ asoc->a_rwnd);
+
+ /* Send a window update SACK if the rwnd has increased by at least the
+ * minimum of the association's PMTU and half of the receive buffer.
+ * The algorithm used is similar to the one described in
+ * Section 4.2.3.3 of RFC 1122.
+ */
+ if (sctp_peer_needs_update(asoc)) {
+ asoc->a_rwnd = asoc->rwnd;
+
+ pr_debug("%s: sending window update SACK- asoc:%p rwnd:%u "
+ "a_rwnd:%u\n", __func__, asoc, asoc->rwnd,
+ asoc->a_rwnd);
+
+ sack = sctp_make_sack(asoc);
+ if (!sack)
+ return;
+
+ asoc->peer.sack_needed = 0;
+
+ sctp_outq_tail(&asoc->outqueue, sack, GFP_ATOMIC);
+
+ /* Stop the SACK timer. */
+ timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
+ if (del_timer(timer))
+ sctp_association_put(asoc);
+ }
+}
+
+/* Decrease asoc's rwnd by len. */
+void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned int len)
+{
+ int rx_count;
+ int over = 0;
+
+ if (unlikely(!asoc->rwnd || asoc->rwnd_over))
+ pr_debug("%s: association:%p has asoc->rwnd:%u, "
+ "asoc->rwnd_over:%u!\n", __func__, asoc,
+ asoc->rwnd, asoc->rwnd_over);
+
+ if (asoc->ep->rcvbuf_policy)
+ rx_count = atomic_read(&asoc->rmem_alloc);
+ else
+ rx_count = atomic_read(&asoc->base.sk->sk_rmem_alloc);
+
+ /* If we've reached or overflowed our receive buffer, announce
+ * a 0 rwnd if rwnd would still be positive. Store the
+ * the potential pressure overflow so that the window can be restored
+ * back to original value.
+ */
+ if (rx_count >= asoc->base.sk->sk_rcvbuf)
+ over = 1;
+
+ if (asoc->rwnd >= len) {
+ asoc->rwnd -= len;
+ if (over) {
+ asoc->rwnd_press += asoc->rwnd;
+ asoc->rwnd = 0;
+ }
+ } else {
+ asoc->rwnd_over += len - asoc->rwnd;
+ asoc->rwnd = 0;
+ }
+
+ pr_debug("%s: asoc:%p rwnd decreased by %d to (%u, %u, %u)\n",
+ __func__, asoc, len, asoc->rwnd, asoc->rwnd_over,
+ asoc->rwnd_press);
+}
+
+/* Build the bind address list for the association based on info from the
+ * local endpoint and the remote peer.
+ */
+int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
+ enum sctp_scope scope, gfp_t gfp)
+{
+ int flags;
+
+ /* Use scoping rules to determine the subset of addresses from
+ * the endpoint.
+ */
+ flags = (PF_INET6 == asoc->base.sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0;
+ if (asoc->peer.ipv4_address)
+ flags |= SCTP_ADDR4_PEERSUPP;
+ if (asoc->peer.ipv6_address)
+ flags |= SCTP_ADDR6_PEERSUPP;
+
+ return sctp_bind_addr_copy(sock_net(asoc->base.sk),
+ &asoc->base.bind_addr,
+ &asoc->ep->base.bind_addr,
+ scope, gfp, flags);
+}
+
+/* Build the association's bind address list from the cookie. */
+int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *asoc,
+ struct sctp_cookie *cookie,
+ gfp_t gfp)
+{
+ int var_size2 = ntohs(cookie->peer_init->chunk_hdr.length);
+ int var_size3 = cookie->raw_addr_list_len;
+ __u8 *raw = (__u8 *)cookie->peer_init + var_size2;
+
+ return sctp_raw_to_bind_addrs(&asoc->base.bind_addr, raw, var_size3,
+ asoc->ep->base.bind_addr.port, gfp);
+}
+
+/* Lookup laddr in the bind address list of an association. */
+int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
+ const union sctp_addr *laddr)
+{
+ int found = 0;
+
+ if ((asoc->base.bind_addr.port == ntohs(laddr->v4.sin_port)) &&
+ sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
+ sctp_sk(asoc->base.sk)))
+ found = 1;
+
+ return found;
+}
+
+/* Set an association id for a given association */
+int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp)
+{
+ bool preload = gfpflags_allow_blocking(gfp);
+ int ret;
+
+ /* If the id is already assigned, keep it. */
+ if (asoc->assoc_id)
+ return 0;
+
+ if (preload)
+ idr_preload(gfp);
+ spin_lock_bh(&sctp_assocs_id_lock);
+ /* 0 is not a valid assoc_id, must be >= 1 */
+ ret = idr_alloc_cyclic(&sctp_assocs_id, asoc, 1, 0, GFP_NOWAIT);
+ spin_unlock_bh(&sctp_assocs_id_lock);
+ if (preload)
+ idr_preload_end();
+ if (ret < 0)
+ return ret;
+
+ asoc->assoc_id = (sctp_assoc_t)ret;
+ return 0;
+}
+
+/* Free the ASCONF queue */
+static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc)
+{
+ struct sctp_chunk *asconf;
+ struct sctp_chunk *tmp;
+
+ list_for_each_entry_safe(asconf, tmp, &asoc->addip_chunk_list, list) {
+ list_del_init(&asconf->list);
+ sctp_chunk_free(asconf);
+ }
+}
+
+/* Free asconf_ack cache */
+static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc)
+{
+ struct sctp_chunk *ack;
+ struct sctp_chunk *tmp;
+
+ list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
+ transmitted_list) {
+ list_del_init(&ack->transmitted_list);
+ sctp_chunk_free(ack);
+ }
+}
+
+/* Clean up the ASCONF_ACK queue */
+void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc)
+{
+ struct sctp_chunk *ack;
+ struct sctp_chunk *tmp;
+
+ /* We can remove all the entries from the queue up to
+ * the "Peer-Sequence-Number".
+ */
+ list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
+ transmitted_list) {
+ if (ack->subh.addip_hdr->serial ==
+ htonl(asoc->peer.addip_serial))
+ break;
+
+ list_del_init(&ack->transmitted_list);
+ sctp_chunk_free(ack);
+ }
+}
+
+/* Find the ASCONF_ACK whose serial number matches ASCONF */
+struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
+ const struct sctp_association *asoc,
+ __be32 serial)
+{
+ struct sctp_chunk *ack;
+
+ /* Walk through the list of cached ASCONF-ACKs and find the
+ * ack chunk whose serial number matches that of the request.
+ */
+ list_for_each_entry(ack, &asoc->asconf_ack_list, transmitted_list) {
+ if (sctp_chunk_pending(ack))
+ continue;
+ if (ack->subh.addip_hdr->serial == serial) {
+ sctp_chunk_hold(ack);
+ return ack;
+ }
+ }
+
+ return NULL;
+}
+
+void sctp_asconf_queue_teardown(struct sctp_association *asoc)
+{
+ /* Free any cached ASCONF_ACK chunk. */
+ sctp_assoc_free_asconf_acks(asoc);
+
+ /* Free the ASCONF queue. */
+ sctp_assoc_free_asconf_queue(asoc);
+
+ /* Free any cached ASCONF chunk. */
+ if (asoc->addip_last_asconf)
+ sctp_chunk_free(asoc->addip_last_asconf);
+}