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Diffstat (limited to '')
| -rw-r--r-- | net/sctp/associola.c | 1746 |
1 files changed, 1746 insertions, 0 deletions
diff --git a/net/sctp/associola.c b/net/sctp/associola.c new file mode 100644 index 000000000..d17708800 --- /dev/null +++ b/net/sctp/associola.c @@ -0,0 +1,1746 @@ +/* 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; + asoc->base.net = sock_net(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) +{ + struct sock *sk = asoc->base.sk; + int flags; + + /* Use scoping rules to determine the subset of addresses from + * the endpoint. + */ + flags = (PF_INET6 == sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0; + if (!inet_v6_ipv6only(sk)) + flags |= SCTP_ADDR4_ALLOWED; + 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); +} |