Linux-2.6.12-rc2v2.6.12-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!

1 files changed, 514 insertions, 0 deletions

diff --git a/net/sctp/transport.c b/net/sctp/transport.c
new file mode 100644
index 000000000000..f30882e1e96a
--- /dev/null
+++ b/net/sctp/transport.c
@@ -0,0 +1,514 @@
+/* SCTP kernel reference Implementation
+ * Copyright (c) 1999-2000 Cisco, Inc.
+ * Copyright (c) 1999-2001 Motorola, Inc.
+ * Copyright (c) 2001-2003 International Business Machines Corp.
+ * 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 tranport representing
+ * a remote transport address.  For local transport addresses, we just use
+ * union sctp_addr.
+ *
+ * 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>
+ *    Ardelle Fan           <ardelle.fan@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 <net/sctp/sctp.h>
+#include <net/sctp/sm.h>
+
+/* 1st Level Abstractions.  */
+
+/* Initialize a new transport from provided memory.  */
+static struct sctp_transport *sctp_transport_init(struct sctp_transport *peer,
+                                                  const union sctp_addr *addr,
+                                                  int gfp)
+{
+        /* Copy in the address.  */
+        peer->ipaddr = *addr;
+        peer->af_specific = sctp_get_af_specific(addr->sa.sa_family);
+        peer->asoc = NULL;
+
+        peer->dst = NULL;
+        memset(&peer->saddr, 0, sizeof(union sctp_addr));
+
+        /* From 6.3.1 RTO Calculation:
+         *
+         * C1) Until an RTT measurement has been made for a packet sent to the
+         * given destination transport address, set RTO to the protocol
+         * parameter 'RTO.Initial'.
+         */
+        peer->rtt = 0;
+        peer->rto = sctp_rto_initial;
+        peer->rttvar = 0;
+        peer->srtt = 0;
+        peer->rto_pending = 0;
+
+        peer->last_time_heard = jiffies;
+        peer->last_time_used = jiffies;
+        peer->last_time_ecne_reduced = jiffies;
+
+        peer->active = SCTP_ACTIVE;
+        peer->hb_allowed = 0;
+
+        /* Initialize the default path max_retrans.  */
+        peer->max_retrans = sctp_max_retrans_path;
+        peer->error_count = 0;
+
+        INIT_LIST_HEAD(&peer->transmitted);
+        INIT_LIST_HEAD(&peer->send_ready);
+        INIT_LIST_HEAD(&peer->transports);
+
+        /* Set up the retransmission timer.  */
+        init_timer(&peer->T3_rtx_timer);
+        peer->T3_rtx_timer.function = sctp_generate_t3_rtx_event;
+        peer->T3_rtx_timer.data = (unsigned long)peer;
+
+        /* Set up the heartbeat timer. */
+        init_timer(&peer->hb_timer);
+        peer->hb_interval = SCTP_DEFAULT_TIMEOUT_HEARTBEAT;
+        peer->hb_timer.function = sctp_generate_heartbeat_event;
+        peer->hb_timer.data = (unsigned long)peer;
+
+        atomic_set(&peer->refcnt, 1);
+        peer->dead = 0;
+
+        peer->malloced = 0;
+
+        /* Initialize the state information for SFR-CACC */
+        peer->cacc.changeover_active = 0;
+        peer->cacc.cycling_changeover = 0;
+        peer->cacc.next_tsn_at_change = 0;
+        peer->cacc.cacc_saw_newack = 0;
+
+        return peer;
+}
+
+/* Allocate and initialize a new transport.  */
+struct sctp_transport *sctp_transport_new(const union sctp_addr *addr, int gfp)
+{
+        struct sctp_transport *transport;
+
+        transport = t_new(struct sctp_transport, gfp);
+        if (!transport)
+                goto fail;
+
+        if (!sctp_transport_init(transport, addr, gfp))
+                goto fail_init;
+
+        transport->malloced = 1;
+        SCTP_DBG_OBJCNT_INC(transport);
+
+        return transport;
+
+fail_init:
+        kfree(transport);
+
+fail:
+        return NULL;
+}
+
+/* This transport is no longer needed.  Free up if possible, or
+ * delay until it last reference count.
+ */
+void sctp_transport_free(struct sctp_transport *transport)
+{
+        transport->dead = 1;
+
+        /* Try to delete the heartbeat timer.  */
+        if (del_timer(&transport->hb_timer))
+                sctp_transport_put(transport);
+
+        /* Delete the T3_rtx timer if it's active.
+         * There is no point in not doing this now and letting
+         * structure hang around in memory since we know
+         * the tranport is going away.
+         */
+        if (timer_pending(&transport->T3_rtx_timer) &&
+            del_timer(&transport->T3_rtx_timer))
+                sctp_transport_put(transport);
+
+
+        sctp_transport_put(transport);
+}
+
+/* Destroy the transport data structure.
+ * Assumes there are no more users of this structure.
+ */
+static void sctp_transport_destroy(struct sctp_transport *transport)
+{
+        SCTP_ASSERT(transport->dead, "Transport is not dead", return);
+
+        if (transport->asoc)
+                sctp_association_put(transport->asoc);
+
+        sctp_packet_free(&transport->packet);
+
+        dst_release(transport->dst);
+        kfree(transport);
+        SCTP_DBG_OBJCNT_DEC(transport);
+}
+
+/* Start T3_rtx timer if it is not already running and update the heartbeat
+ * timer.  This routine is called every time a DATA chunk is sent.
+ */
+void sctp_transport_reset_timers(struct sctp_transport *transport)
+{
+        /* RFC 2960 6.3.2 Retransmission Timer Rules
+         *
+         * R1) Every time a DATA chunk is sent to any address(including a
+         * retransmission), if the T3-rtx timer of that address is not running
+         * start it running so that it will expire after the RTO of that
+         * address.
+         */
+
+        if (!timer_pending(&transport->T3_rtx_timer))
+                if (!mod_timer(&transport->T3_rtx_timer,
+                               jiffies + transport->rto))
+                        sctp_transport_hold(transport);
+
+        /* When a data chunk is sent, reset the heartbeat interval.  */
+        if (!mod_timer(&transport->hb_timer,
+                       sctp_transport_timeout(transport)))
+            sctp_transport_hold(transport);
+}
+
+/* This transport has been assigned to an association.
+ * Initialize fields from the association or from the sock itself.
+ * Register the reference count in the association.
+ */
+void sctp_transport_set_owner(struct sctp_transport *transport,
+                              struct sctp_association *asoc)
+{
+        transport->asoc = asoc;
+        sctp_association_hold(asoc);
+}
+
+/* Initialize the pmtu of a transport. */
+void sctp_transport_pmtu(struct sctp_transport *transport)
+{
+        struct dst_entry *dst;
+
+        dst = transport->af_specific->get_dst(NULL, &transport->ipaddr, NULL);
+
+        if (dst) {
+                transport->pmtu = dst_mtu(dst);
+                dst_release(dst);
+        } else
+                transport->pmtu = SCTP_DEFAULT_MAXSEGMENT;
+}
+
+/* Caches the dst entry and source address for a transport's destination
+ * address.
+ */
+void sctp_transport_route(struct sctp_transport *transport,
+                          union sctp_addr *saddr, struct sctp_sock *opt)
+{
+        struct sctp_association *asoc = transport->asoc;
+        struct sctp_af *af = transport->af_specific;
+        union sctp_addr *daddr = &transport->ipaddr;
+        struct dst_entry *dst;
+
+        dst = af->get_dst(asoc, daddr, saddr);
+
+        if (saddr)
+                memcpy(&transport->saddr, saddr, sizeof(union sctp_addr));
+        else
+                af->get_saddr(asoc, dst, daddr, &transport->saddr);
+
+        transport->dst = dst;
+        if (dst) {
+                transport->pmtu = dst_mtu(dst);
+
+                /* Initialize sk->sk_rcv_saddr, if the transport is the
+                 * association's active path for getsockname().
+                 */ 
+                if (asoc && (transport == asoc->peer.active_path))
+                        af->to_sk_saddr(&transport->saddr, asoc->base.sk);
+        } else
+                transport->pmtu = SCTP_DEFAULT_MAXSEGMENT;
+}
+
+/* Hold a reference to a transport.  */
+void sctp_transport_hold(struct sctp_transport *transport)
+{
+        atomic_inc(&transport->refcnt);
+}
+
+/* Release a reference to a transport and clean up
+ * if there are no more references.
+ */
+void sctp_transport_put(struct sctp_transport *transport)
+{
+        if (atomic_dec_and_test(&transport->refcnt))
+                sctp_transport_destroy(transport);
+}
+
+/* Update transport's RTO based on the newly calculated RTT. */
+void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt)
+{
+        /* Check for valid transport.  */
+        SCTP_ASSERT(tp, "NULL transport", return);
+
+        /* We should not be doing any RTO updates unless rto_pending is set.  */
+        SCTP_ASSERT(tp->rto_pending, "rto_pending not set", return);
+
+        if (tp->rttvar || tp->srtt) {
+                /* 6.3.1 C3) When a new RTT measurement R' is made, set
+                 * RTTVAR <- (1 - RTO.Beta) * RTTVAR + RTO.Beta * |SRTT - R'|
+                 * SRTT <- (1 - RTO.Alpha) * SRTT + RTO.Alpha * R'
+                 */
+
+                /* Note:  The above algorithm has been rewritten to
+                 * express rto_beta and rto_alpha as inverse powers
+                 * of two.
+                 * For example, assuming the default value of RTO.Alpha of
+                 * 1/8, rto_alpha would be expressed as 3.
+                 */
+                tp->rttvar = tp->rttvar - (tp->rttvar >> sctp_rto_beta)
+                        + ((abs(tp->srtt - rtt)) >> sctp_rto_beta);
+                tp->srtt = tp->srtt - (tp->srtt >> sctp_rto_alpha)
+                        + (rtt >> sctp_rto_alpha);
+        } else {
+                /* 6.3.1 C2) When the first RTT measurement R is made, set
+                 * SRTT <- R, RTTVAR <- R/2.
+                 */
+                tp->srtt = rtt;
+                tp->rttvar = rtt >> 1;
+        }
+
+        /* 6.3.1 G1) Whenever RTTVAR is computed, if RTTVAR = 0, then
+         * adjust RTTVAR <- G, where G is the CLOCK GRANULARITY.
+         */
+        if (tp->rttvar == 0)
+                tp->rttvar = SCTP_CLOCK_GRANULARITY;
+
+        /* 6.3.1 C3) After the computation, update RTO <- SRTT + 4 * RTTVAR. */
+        tp->rto = tp->srtt + (tp->rttvar << 2);
+
+        /* 6.3.1 C6) Whenever RTO is computed, if it is less than RTO.Min
+         * seconds then it is rounded up to RTO.Min seconds.
+         */
+        if (tp->rto < tp->asoc->rto_min)
+                tp->rto = tp->asoc->rto_min;
+
+        /* 6.3.1 C7) A maximum value may be placed on RTO provided it is
+         * at least RTO.max seconds.
+         */
+        if (tp->rto > tp->asoc->rto_max)
+                tp->rto = tp->asoc->rto_max;
+
+        tp->rtt = rtt;
+
+        /* Reset rto_pending so that a new RTT measurement is started when a
+         * new data chunk is sent.
+         */
+        tp->rto_pending = 0;
+
+        SCTP_DEBUG_PRINTK("%s: transport: %p, rtt: %d, srtt: %d "
+                          "rttvar: %d, rto: %d\n", __FUNCTION__,
+                          tp, rtt, tp->srtt, tp->rttvar, tp->rto);
+}
+
+/* This routine updates the transport's cwnd and partial_bytes_acked
+ * parameters based on the bytes acked in the received SACK.
+ */
+void sctp_transport_raise_cwnd(struct sctp_transport *transport,
+                               __u32 sack_ctsn, __u32 bytes_acked)
+{
+        __u32 cwnd, ssthresh, flight_size, pba, pmtu;
+
+        cwnd = transport->cwnd;
+        flight_size = transport->flight_size;
+
+        /* The appropriate cwnd increase algorithm is performed if, and only
+         * if the cumulative TSN has advanced and the congestion window is
+         * being fully utilized.
+         */
+        if ((transport->asoc->ctsn_ack_point >= sack_ctsn) ||
+            (flight_size < cwnd))
+                return;
+
+        ssthresh = transport->ssthresh;
+        pba = transport->partial_bytes_acked;
+        pmtu = transport->asoc->pmtu;
+
+        if (cwnd <= ssthresh) {
+                /* RFC 2960 7.2.1, sctpimpguide-05 2.14.2 When cwnd is less
+                 * than or equal to ssthresh an SCTP endpoint MUST use the
+                 * slow start algorithm to increase cwnd only if the current
+                 * congestion window is being fully utilized and an incoming
+                 * SACK advances the Cumulative TSN Ack Point. Only when these
+                 * two conditions are met can the cwnd be increased otherwise
+                 * the cwnd MUST not be increased. If these conditions are met
+                 * then cwnd MUST be increased by at most the lesser of
+                 * 1) the total size of the previously outstanding DATA
+                 * chunk(s) acknowledged, and 2) the destination's path MTU.
+                 */
+                if (bytes_acked > pmtu)
+                        cwnd += pmtu;
+                else
+                        cwnd += bytes_acked;
+                SCTP_DEBUG_PRINTK("%s: SLOW START: transport: %p, "
+                                  "bytes_acked: %d, cwnd: %d, ssthresh: %d, "
+                                  "flight_size: %d, pba: %d\n",
+                                  __FUNCTION__,
+                                  transport, bytes_acked, cwnd,
+                                  ssthresh, flight_size, pba);
+        } else {
+                /* RFC 2960 7.2.2 Whenever cwnd is greater than ssthresh,
+                 * upon each SACK arrival that advances the Cumulative TSN Ack
+                 * Point, increase partial_bytes_acked by the total number of
+                 * bytes of all new chunks acknowledged in that SACK including
+                 * chunks acknowledged by the new Cumulative TSN Ack and by
+                 * Gap Ack Blocks.
+                 *
+                 * When partial_bytes_acked is equal to or greater than cwnd
+                 * and before the arrival of the SACK the sender had cwnd or
+                 * more bytes of data outstanding (i.e., before arrival of the
+                 * SACK, flightsize was greater than or equal to cwnd),
+                 * increase cwnd by MTU, and reset partial_bytes_acked to
+                 * (partial_bytes_acked - cwnd).
+                 */
+                pba += bytes_acked;
+                if (pba >= cwnd) {
+                        cwnd += pmtu;
+                        pba = ((cwnd < pba) ? (pba - cwnd) : 0);
+                }
+                SCTP_DEBUG_PRINTK("%s: CONGESTION AVOIDANCE: "
+                                  "transport: %p, bytes_acked: %d, cwnd: %d, "
+                                  "ssthresh: %d, flight_size: %d, pba: %d\n",
+                                  __FUNCTION__,
+                                  transport, bytes_acked, cwnd,
+                                  ssthresh, flight_size, pba);
+        }
+
+        transport->cwnd = cwnd;
+        transport->partial_bytes_acked = pba;
+}
+
+/* This routine is used to lower the transport's cwnd when congestion is
+ * detected.
+ */
+void sctp_transport_lower_cwnd(struct sctp_transport *transport,
+                               sctp_lower_cwnd_t reason)
+{
+        switch (reason) {
+        case SCTP_LOWER_CWND_T3_RTX:
+                /* RFC 2960 Section 7.2.3, sctpimpguide
+                 * When the T3-rtx timer expires on an address, SCTP should
+                 * perform slow start by:
+                 *      ssthresh = max(cwnd/2, 4*MTU)
+                 *      cwnd = 1*MTU
+                 *      partial_bytes_acked = 0
+                 */
+                transport->ssthresh = max(transport->cwnd/2,
+                                          4*transport->asoc->pmtu);
+                transport->cwnd = transport->asoc->pmtu;
+                break;
+
+        case SCTP_LOWER_CWND_FAST_RTX:
+                /* RFC 2960 7.2.4 Adjust the ssthresh and cwnd of the
+                 * destination address(es) to which the missing DATA chunks
+                 * were last sent, according to the formula described in
+                 * Section 7.2.3.
+                 *
+                 * RFC 2960 7.2.3, sctpimpguide Upon detection of packet
+                 * losses from SACK (see Section 7.2.4), An endpoint
+                 * should do the following:
+                 *      ssthresh = max(cwnd/2, 4*MTU)
+                 *      cwnd = ssthresh
+                 *      partial_bytes_acked = 0
+                 */
+                transport->ssthresh = max(transport->cwnd/2,
+                                          4*transport->asoc->pmtu);
+                transport->cwnd = transport->ssthresh;
+                break;
+
+        case SCTP_LOWER_CWND_ECNE:
+                /* RFC 2481 Section 6.1.2.
+                 * If the sender receives an ECN-Echo ACK packet
+                 * then the sender knows that congestion was encountered in the
+                 * network on the path from the sender to the receiver. The
+                 * indication of congestion should be treated just as a
+                 * congestion loss in non-ECN Capable TCP. That is, the TCP
+                 * source halves the congestion window "cwnd" and reduces the
+                 * slow start threshold "ssthresh".
+                 * A critical condition is that TCP does not react to
+                 * congestion indications more than once every window of
+                 * data (or more loosely more than once every round-trip time).
+                 */
+                if ((jiffies - transport->last_time_ecne_reduced) >
+                    transport->rtt) {
+                        transport->ssthresh = max(transport->cwnd/2,
+                                                  4*transport->asoc->pmtu);
+                        transport->cwnd = transport->ssthresh;
+                        transport->last_time_ecne_reduced = jiffies;
+                }
+                break;
+
+        case SCTP_LOWER_CWND_INACTIVE:
+                /* RFC 2960 Section 7.2.1, sctpimpguide
+                 * When the endpoint does not transmit data on a given
+                 * transport address, the cwnd of the transport address
+                 * should be adjusted to max(cwnd/2, 4*MTU) per RTO.
+                 * NOTE: Although the draft recommends that this check needs
+                 * to be done every RTO interval, we do it every hearbeat
+                 * interval.
+                 */
+                if ((jiffies - transport->last_time_used) > transport->rto)
+                        transport->cwnd = max(transport->cwnd/2,
+                                                 4*transport->asoc->pmtu);
+                break;
+        };
+
+        transport->partial_bytes_acked = 0;
+        SCTP_DEBUG_PRINTK("%s: transport: %p reason: %d cwnd: "
+                          "%d ssthresh: %d\n", __FUNCTION__,
+                          transport, reason,
+                          transport->cwnd, transport->ssthresh);
+}
+
+/* What is the next timeout value for this transport? */
+unsigned long sctp_transport_timeout(struct sctp_transport *t)
+{
+        unsigned long timeout;
+        timeout = t->hb_interval + t->rto + sctp_jitter(t->rto);
+        timeout += jiffies;
+        return timeout;
+}