diff options
Diffstat (limited to 'net/sctp/associola.c')
| -rw-r--r-- | net/sctp/associola.c | 1205 |
1 files changed, 1205 insertions, 0 deletions
diff --git a/net/sctp/associola.c b/net/sctp/associola.c new file mode 100644 index 000000000000..663843d97a92 --- /dev/null +++ b/net/sctp/associola.c @@ -0,0 +1,1205 @@ +/* SCTP kernel reference 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 reference Implementation + * + * This module provides the abstraction for an SCTP association. + * + * The SCTP reference 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. + * + * The SCTP reference 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, write to + * the Free Software Foundation, 59 Temple Place - Suite 330, + * Boston, MA 02111-1307, USA. + * + * Please send any bug reports or fixes you make to the + * email address(es): + * lksctp developers <lksctp-developers@lists.sourceforge.net> + * + * Or submit a bug report through the following website: + * http://www.sf.net/projects/lksctp + * + * 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> + * + * Any bugs reported given to us we will try to fix... any fixes shared will + * be incorporated into the next SCTP release. + */ + +#include <linux/types.h> +#include <linux/fcntl.h> +#include <linux/poll.h> +#include <linux/init.h> +#include <linux/sched.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_assoc_bh_rcv(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, + int gfp) +{ + struct sctp_sock *sp; + int i; + + /* Retrieve the SCTP per socket area. */ + sp = sctp_sk((struct sock *)sk); + + /* Init all variables to a known value. */ + memset(asoc, 0, sizeof(struct sctp_association)); + + /* Discarding const is appropriate here. */ + asoc->ep = (struct sctp_endpoint *)ep; + sctp_endpoint_hold(asoc->ep); + + /* Hold the sock. */ + asoc->base.sk = (struct sock *)sk; + 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); + asoc->base.dead = 0; + asoc->base.malloced = 0; + + /* Initialize the bind addr area. */ + sctp_bind_addr_init(&asoc->base.bind_addr, ep->base.bind_addr.port); + rwlock_init(&asoc->base.addr_lock); + + asoc->state = SCTP_STATE_CLOSED; + + /* Set these values from the socket values, a conversion between + * millsecons to seconds/microseconds must also be done. + */ + asoc->cookie_life.tv_sec = sp->assocparams.sasoc_cookie_life / 1000; + asoc->cookie_life.tv_usec = (sp->assocparams.sasoc_cookie_life % 1000) + * 1000; + asoc->pmtu = 0; + asoc->frag_point = 0; + + /* Set the association max_retrans and RTO values from the + * socket values. + */ + asoc->max_retrans = sp->assocparams.sasoc_asocmaxrxt; + 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); + + asoc->overall_error_count = 0; + + /* Initialize the maximum mumber of new data packets that can be sent + * in a burst. + */ + asoc->max_burst = sctp_max_burst; + + /* Copy things from the endpoint. */ + for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) { + asoc->timeouts[i] = ep->timeouts[i]; + init_timer(&asoc->timers[i]); + asoc->timers[i].function = sctp_timer_events[i]; + asoc->timers[i].data = (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); + + /* Allocate storage for the ssnmap after the inbound and outbound + * streams have been negotiated during Init. + */ + asoc->ssnmap = NULL; + + /* 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 < SCTP_DEFAULT_MINWINDOW) + asoc->rwnd = SCTP_DEFAULT_MINWINDOW; + else + asoc->rwnd = sk->sk_rcvbuf; + + asoc->a_rwnd = asoc->rwnd; + + asoc->rwnd_over = 0; + + /* Use my own max window until I learn something better. */ + asoc->peer.rwnd = SCTP_DEFAULT_MAXWINDOW; + + /* Set the sndbuf size for transmit. */ + asoc->sndbuf_used = 0; + + init_waitqueue_head(&asoc->wait); + + asoc->c.my_vtag = sctp_generate_tag(ep); + asoc->peer.i.init_tag = 0; /* INIT needs a vtag of 0. */ + asoc->c.peer_vtag = 0; + asoc->c.my_ttag = 0; + asoc->c.peer_ttag = 0; + 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; + asoc->unack_data = 0; + + SCTP_DEBUG_PRINTK("myctsnap for %s INIT as 0x%x.\n", + asoc->ep->debug_name, + 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; + + skb_queue_head_init(&asoc->addip_chunks); + + /* 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; + + /* Assume that the peer recongizes ASCONF until reported otherwise + * via an ERROR chunk. + */ + asoc->peer.asconf_capable = 1; + + /* Create an input queue. */ + sctp_inq_init(&asoc->base.inqueue); + sctp_inq_set_th_handler(&asoc->base.inqueue, + (void (*)(void *))sctp_assoc_bh_rcv, + asoc); + + /* Create an output queue. */ + sctp_outq_init(asoc, &asoc->outqueue); + + if (!sctp_ulpq_init(&asoc->ulpq, asoc)) + goto fail_init; + + /* Set up the tsn tracking. */ + sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_SIZE, 0); + + asoc->need_ecne = 0; + + asoc->assoc_id = 0; + + /* Assume that peer would support both address types unless we are + * told otherwise. + */ + asoc->peer.ipv4_address = 1; + 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; + + return asoc; + +fail_init: + sctp_endpoint_put(asoc->ep); + sock_put(asoc->base.sk); + 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, int gfp) +{ + struct sctp_association *asoc; + + asoc = t_new(struct sctp_association, gfp); + if (!asoc) + goto fail; + + if (!sctp_association_init(asoc, ep, sk, scope, gfp)) + goto fail_init; + + asoc->base.malloced = 1; + SCTP_DBG_OBJCNT_INC(assoc); + + 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; + + 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 = 1; + + /* 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); + + /* 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 (timer_pending(&asoc->timers[i]) && + del_timer(&asoc->timers[i])) + sctp_association_put(asoc); + } + + /* Free peer's cached cookie. */ + if (asoc->peer.cookie) { + kfree(asoc->peer.cookie); + } + + /* 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(pos); + sctp_transport_free(transport); + } + + /* Free any cached ASCONF_ACK chunk. */ + if (asoc->addip_last_asconf_ack) + sctp_chunk_free(asoc->addip_last_asconf_ack); + + /* Free any cached ASCONF chunk. */ + if (asoc->addip_last_asconf) + sctp_chunk_free(asoc->addip_last_asconf); + + sctp_association_put(asoc); +} + +/* Cleanup and free up an association. */ +static void sctp_association_destroy(struct sctp_association *asoc) +{ + SCTP_ASSERT(asoc->base.dead, "Assoc is not dead", 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); + } + + if (asoc->base.malloced) { + 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) +{ + 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->active) + 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. + */ + if (transport->cacc.changeover_active) + transport->cacc.cycling_changeover = 1; + + /* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that + * a changeover has occurred. + */ + transport->cacc.changeover_active = 1; + + /* 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; +} + +/* Add a transport address to an association. */ +struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc, + const union sctp_addr *addr, + int gfp) +{ + 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 = addr->v4.sin_port; + + /* 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) + return peer; + + peer = sctp_transport_new(addr, gfp); + if (!peer) + return NULL; + + sctp_transport_set_owner(peer, asoc); + + /* Initialize the pmtu of the transport. */ + sctp_transport_pmtu(peer); + + /* 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->pmtu) + asoc->pmtu = min_t(int, peer->pmtu, asoc->pmtu); + else + asoc->pmtu = peer->pmtu; + + SCTP_DEBUG_PRINTK("sctp_assoc_add_peer:association %p PMTU set to " + "%d\n", asoc, asoc->pmtu); + + asoc->frag_point = sctp_frag_point(sp, asoc->pmtu); + + /* 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->pmtu, max_t(__u32, 2*asoc->pmtu, 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; + + /* By default, enable heartbeat for peer address. */ + peer->hb_allowed = 1; + + /* Initialize the peer's heartbeat interval based on the + * sock configured value. + */ + peer->hb_interval = msecs_to_jiffies(sp->paddrparam.spp_hbinterval); + + /* Set the path max_retrans. */ + peer->max_retrans = sp->paddrparam.spp_pathmaxrxt; + + /* Set the transport's RTO.initial value */ + peer->rto = asoc->rto_initial; + + /* Attach the remote transport to our asoc. */ + list_add_tail(&peer->transports, &asoc->peer.transport_addr_list); + + /* 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) + 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 *peer = NULL; + 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)) { + peer = transport; + list_del(pos); + break; + } + } + + /* The address we want delete is not in the association. */ + if (!peer) + return; + + /* 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; + + sctp_transport_free(peer); +} + +/* 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; + struct list_head *pos; + + /* Cycle through all transports searching for a peer address. */ + + list_for_each(pos, &asoc->peer.transport_addr_list) { + t = list_entry(pos, struct sctp_transport, transports); + if (sctp_cmp_addr_exact(address, &t->ipaddr)) + return t; + } + + return NULL; +} + +/* 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 list_head *pos; + int spc_state = 0; + + /* Record the transition on the transport. */ + switch (command) { + case SCTP_TRANSPORT_UP: + transport->active = SCTP_ACTIVE; + spc_state = SCTP_ADDR_AVAILABLE; + break; + + case SCTP_TRANSPORT_DOWN: + transport->active = SCTP_INACTIVE; + spc_state = SCTP_ADDR_UNREACHABLE; + break; + + default: + return; + }; + + /* Generate and send a SCTP_PEER_ADDR_CHANGE notification to the + * user. + */ + event = sctp_ulpevent_make_peer_addr_change(asoc, + (struct sockaddr_storage *) &transport->ipaddr, + 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(pos, &asoc->peer.transport_addr_list) { + t = list_entry(pos, struct sctp_transport, transports); + + if (!t->active) + continue; + if (!first || t->last_time_heard > first->last_time_heard) { + second = first; + first = t; + } + 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->active && + first != asoc->peer.primary_path) { + second = first; + first = asoc->peer.primary_path; + } + + /* 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) +{ + struct sctp_chunk *chunk; + + /* Send ECNE if needed. + * Not being able to allocate a chunk here is not deadly. + */ + if (asoc->need_ecne) + chunk = sctp_make_ecne(asoc, asoc->last_ecne_tsn); + else + chunk = NULL; + + return chunk; +} + +/* + * 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 list_head *entry, *pos; + struct sctp_transport *transport; + struct sctp_chunk *chunk; + __u32 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, &active->transmitted) { + chunk = list_entry(entry, struct sctp_chunk, 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(pos, &asoc->peer.transport_addr_list) { + transport = list_entry(pos, struct sctp_transport, transports); + + if (transport == active) + break; + list_for_each(entry, &transport->transmitted) { + chunk = list_entry(entry, struct sctp_chunk, + 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, + const union sctp_addr *laddr, + const union sctp_addr *paddr) +{ + struct sctp_transport *transport; + + sctp_read_lock(&asoc->base.addr_lock); + + if ((asoc->base.bind_addr.port == laddr->v4.sin_port) && + (asoc->peer.port == paddr->v4.sin_port)) { + 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: + sctp_read_unlock(&asoc->base.addr_lock); + return transport; +} + +/* Do delayed input processing. This is scheduled by sctp_rcv(). */ +static void sctp_assoc_bh_rcv(struct sctp_association *asoc) +{ + struct sctp_endpoint *ep; + struct sctp_chunk *chunk; + struct sock *sk; + 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; + sk = asoc->base.sk; + + 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); + + /* 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(SCTP_MIB_INCTRLCHUNKS); + + if (chunk->transport) + chunk->transport->last_time_heard = jiffies; + + /* Run through the state machine. */ + error = sctp_do_sm(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_SIZE, + asoc->peer.i.initial_tsn); + + /* 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_del_peer(asoc, &trans->ipaddr); + } + + /* 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); + + } else { + /* Add any peer addresses from the new association. */ + list_for_each(pos, &new->peer.transport_addr_list) { + trans = list_entry(pos, struct sctp_transport, + transports); + if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr)) + sctp_assoc_add_peer(asoc, &trans->ipaddr, + GFP_ATOMIC); + } + + 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; + } + } +} + +/* 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; + + /* 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); + + /* Try to find an active transport. */ + + if (t->active) { + break; + } else { + /* Keep track of the next transport in case + * we don't find any active transport. + */ + if (!next) + next = t; + } + + /* 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; + } + } + + asoc->peer.retran_path = t; +} + +/* Choose the transport for sending a SHUTDOWN packet. */ +struct sctp_transport *sctp_assoc_choose_shutdown_transport( + struct sctp_association *asoc) +{ + /* If this is the first time SHUTDOWN is sent, use the active path, + * else use the retran path. If the last SHUTDOWN was sent over the + * retran path, update the retran path and use it. + */ + if (!asoc->shutdown_last_sent_to) + return asoc->peer.active_path; + else { + if (asoc->shutdown_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 sctp_association *asoc) +{ + struct sctp_transport *t; + struct list_head *pos; + __u32 pmtu = 0; + + if (!asoc) + return; + + /* Get the lowest pmtu of all the transports. */ + list_for_each(pos, &asoc->peer.transport_addr_list) { + t = list_entry(pos, struct sctp_transport, transports); + if (!pmtu || (t->pmtu < pmtu)) + pmtu = t->pmtu; + } + + if (pmtu) { + struct sctp_sock *sp = sctp_sk(asoc->base.sk); + asoc->pmtu = pmtu; + asoc->frag_point = sctp_frag_point(sp, pmtu); + } + + SCTP_DEBUG_PRINTK("%s: asoc:%p, pmtu:%d, frag_point:%d\n", + __FUNCTION__, asoc, asoc->pmtu, asoc->frag_point); +} + +/* Should we send a SACK to update our peer? */ +static inline int sctp_peer_needs_update(struct sctp_association *asoc) +{ + 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) >= + min_t(__u32, (asoc->base.sk->sk_rcvbuf >> 1), asoc->pmtu))) + 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 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; + } + + SCTP_DEBUG_PRINTK("%s: asoc %p rwnd increased by %d to (%u, %u) " + "- %u\n", __FUNCTION__, 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; + SCTP_DEBUG_PRINTK("%s: Sending window update SACK- asoc: %p " + "rwnd: %u a_rwnd: %u\n", __FUNCTION__, + 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 (timer_pending(timer) && del_timer(timer)) + sctp_association_put(asoc); + } +} + +/* Decrease asoc's rwnd by len. */ +void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned len) +{ + SCTP_ASSERT(asoc->rwnd, "rwnd zero", return); + SCTP_ASSERT(!asoc->rwnd_over, "rwnd_over not zero", return); + if (asoc->rwnd >= len) { + asoc->rwnd -= len; + } else { + asoc->rwnd_over = len - asoc->rwnd; + asoc->rwnd = 0; + } + SCTP_DEBUG_PRINTK("%s: asoc %p rwnd decreased by %d to (%u, %u)\n", + __FUNCTION__, asoc, len, asoc->rwnd, + asoc->rwnd_over); +} + +/* 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, int gfp) +{ + sctp_scope_t scope; + int flags; + + /* Use scoping rules to determine the subset of addresses from + * the endpoint. + */ + scope = sctp_scope(&asoc->peer.active_path->ipaddr); + 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(&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, int 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; + + sctp_read_lock(&asoc->base.addr_lock); + 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; + goto out; + } + + found = 0; +out: + sctp_read_unlock(&asoc->base.addr_lock); + return found; +} |