/* 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 * . * * Please send any bug reports or fixes you make to the * email address(es): * lksctp developers * * Written or modified by: * La Monte H.P. Yarroll * Karl Knutson * Jon Grimm * Xingang Guo * Hui Huang * Sridhar Samudrala * Daisy Chang * Ryan Layer * Kevin Gao */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include /* Forward declarations for internal functions. */ 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, sctp_scope_t scope, gfp_t gfp) { struct net *net = sock_net(sk); struct sctp_sock *sp; int i; sctp_paramhdr_t *p; int err; /* 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. */ atomic_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; /* Initialize default path MTU. */ asoc->pathmtu = sp->pathmtu; /* 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 mumber 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] = min_t(unsigned long, sp->autoclose, net->sctp.max_autoclose) * HZ; /* Initializes the timers */ for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) setup_timer(&asoc->timers[i], sctp_timer_events[i], (unsigned long)asoc); /* 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; 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 compatibilty * 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; /* 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->autoclose = sp->autoclose; 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); err = sctp_auth_asoc_copy_shkeys(ep, asoc, gfp); if (err) goto fail_init; asoc->active_key_id = ep->active_key_id; /* 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 = (sctp_paramhdr_t *)asoc->c.auth_random; p->type = SCTP_PARAM_RANDOM; p->length = htons(sizeof(sctp_paramhdr_t) + SCTP_AUTH_RANDOM_LENGTH); get_random_bytes(p+1, SCTP_AUTH_RANDOM_LENGTH); return asoc; 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, sctp_scope_t 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 (!asoc->temp) { 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 ssnmap storage. */ sctp_ssnmap_free(asoc->ssnmap); /* 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_transport_free(transport); } asoc->peer.transport_count = 0; sctp_asconf_queue_teardown(asoc); /* Free pending address space being deleted */ if (asoc->asconf_addr_del_pending != NULL) 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(asoc); 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 list_head *pos; struct sctp_transport *transport; 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); /* 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 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; struct sctp_chunk *ch; /* 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); } 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; /* Enable/disable heartbeat, SACK delay, and path MTU discovery * based on association setting. */ peer->param_flags = asoc->param_flags; sctp_transport_route(peer, NULL, sp); /* Initialize the pmtu of the transport. */ if (peer->param_flags & SPP_PMTUD_DISABLE) { if (asoc->pathmtu) peer->pathmtu = asoc->pathmtu; else peer->pathmtu = SCTP_DEFAULT_MAXSEGMENT; } /* 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. */ if (asoc->pathmtu) asoc->pathmtu = min_t(int, peer->pathmtu, asoc->pathmtu); else asoc->pathmtu = peer->pathmtu; pr_debug("%s: association:%p PMTU set to %d\n", __func__, asoc, asoc->pathmtu); peer->pmtu_pending = 0; asoc->frag_point = sctp_frag_point(asoc, asoc->pathmtu); /* 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; /* 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, sctp_transport_cmd_t command, sctp_sn_error_t error) { struct sctp_transport *t = NULL; struct sctp_transport *first; struct sctp_transport *second; 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 { dst_release(transport->dst); transport->dst = NULL; } 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) sctp_ulpq_tail_event(&asoc->ulpq, event); } /* Select new active and retran paths. */ /* Look for the two most recently used active transports. * * This code produces the wrong ordering whenever jiffies * rolls over, but we still get usable transports, so we don't * worry about it. */ first = NULL; second = NULL; list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) { if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED) || (t->state == SCTP_PF)) continue; if (!first || t->last_time_heard > first->last_time_heard) { second = first; first = t; } else if (!second || t->last_time_heard > second->last_time_heard) second = t; } /* 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)) && first != asoc->peer.primary_path) { second = first; first = asoc->peer.primary_path; } if (!second) second = first; /* If we failed to find a usable transport, just camp on the * primary, even if it is inactive. */ if (!first) { first = asoc->peer.primary_path; second = asoc->peer.primary_path; } /* Set the active and retran transports. */ asoc->peer.active_path = first; asoc->peer.retran_path = second; } /* Hold a reference to an association. */ void sctp_association_hold(struct sctp_association *asoc) { atomic_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 (atomic_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; } /* Is this the association we are looking for? */ struct sctp_transport *sctp_assoc_is_match(struct sctp_association *asoc, struct net *net, const union sctp_addr *laddr, const union sctp_addr *paddr) { struct sctp_transport *transport; if ((htons(asoc->base.bind_addr.port) == laddr->v4.sin_port) && (htons(asoc->peer.port) == paddr->v4.sin_port) && net_eq(sock_net(asoc->base.sk), net)) { transport = sctp_assoc_lookup_paddr(asoc, paddr); if (!transport) goto out; if (sctp_bind_addr_match(&asoc->base.bind_addr, laddr, sctp_sk(asoc->base.sk))) goto out; } transport = NULL; out: return transport; } /* 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); struct sctp_endpoint *ep; struct sctp_chunk *chunk; struct sctp_inq *inqueue; int state; sctp_subtype_t subtype; int error = 0; /* 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); /* 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 = jiffies; /* 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; } 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). */ void 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.i = new->peer.i; sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL, asoc->peer.i.initial_tsn, GFP_ATOMIC); /* 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_ssnmap_clear(asoc->ssnmap); /* 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); } asoc->ctsn_ack_point = asoc->next_tsn - 1; asoc->adv_peer_ack_point = asoc->ctsn_ack_point; if (!asoc->ssnmap) { /* Move the ssnmap. */ asoc->ssnmap = new->ssnmap; new->ssnmap = NULL; } if (!asoc->assoc_id) { /* get a new association id since we don't have one * yet. */ sctp_assoc_set_id(asoc, GFP_ATOMIC); } } /* SCTP-AUTH: Save the peer parameters from the new assocaitions * 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; sctp_auth_key_put(asoc->asoc_shared_key); sctp_auth_asoc_init_active_key(asoc, GFP_ATOMIC); } /* Update the retran path for sending a retransmitted packet. * Round-robin through the active transports, else round-robin * through the inactive transports as this is the next best thing * we can try. */ void sctp_assoc_update_retran_path(struct sctp_association *asoc) { struct sctp_transport *t, *next; struct list_head *head = &asoc->peer.transport_addr_list; struct list_head *pos; if (asoc->peer.transport_count == 1) return; /* Find the next transport in a round-robin fashion. */ t = asoc->peer.retran_path; pos = &t->transports; next = NULL; while (1) { /* Skip the head. */ if (pos->next == head) pos = head->next; else pos = pos->next; t = list_entry(pos, struct sctp_transport, transports); /* We have exhausted the list, but didn't find any * other active transports. If so, use the next * transport. */ if (t == asoc->peer.retran_path) { t = next; break; } /* Try to find an active transport. */ if ((t->state == SCTP_ACTIVE) || (t->state == SCTP_UNKNOWN)) { break; } else { /* Keep track of the next transport in case * we don't find any active transport. */ if (t->state != SCTP_UNCONFIRMED && !next) next = t; } } if (t) asoc->peer.retran_path = t; else t = asoc->peer.retran_path; pr_debug("%s: association:%p addr:%pISpc\n", __func__, asoc, &t->ipaddr.sa); } /* Choose the transport for sending retransmit packet. */ 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) 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; } } /* 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 sock *sk, 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(sk, t, dst_mtu(t->dst)); t->pmtu_pending = 0; } if (!pmtu || (t->pathmtu < pmtu)) pmtu = t->pathmtu; } if (pmtu) { asoc->pathmtu = pmtu; asoc->frag_point = sctp_frag_point(asoc, pmtu); } pr_debug("%s: asoc:%p, pmtu:%d, frag_point:%d\n", __func__, asoc, asoc->pathmtu, asoc->frag_point); } /* Should we send a SACK to update our peer? */ static inline int 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 1; break; default: break; } return 0; } /* 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 && asoc->rwnd >= 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); /* 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 pottential 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, sctp_scope_t 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 = gfp & __GFP_WAIT; 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 (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); }