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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /net/sctp/associola.c
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'net/sctp/associola.c')
-rw-r--r--net/sctp/associola.c1205
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;
+}