[SCTP]: Verify all the paths to a peer via heartbeat before using them.

This patch implements Path Initialization procedure as described in
Sec 2.36 of RFC4460.

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

8 files changed, 60 insertions, 19 deletions

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 5f69158c1006..268f2e19ccbb 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -445,6 +445,7 @@ typedef struct sctp_sender_hb_info {
         struct sctp_paramhdr param_hdr;
         union sctp_addr daddr;
         unsigned long sent_at;
+        __u64 hb_nonce;
 } __attribute__((packed)) sctp_sender_hb_info_t;
 
 /*
@@ -984,6 +985,9 @@ struct sctp_transport {
                  */
                 char cacc_saw_newack;
         } cacc;
+
+        /* 64-bit random number sent with heartbeat. */
+        __u64 hb_nonce;
 };
 
 struct sctp_transport *sctp_transport_new(const union sctp_addr *,
diff --git a/include/net/sctp/user.h b/include/net/sctp/user.h
index 8a6bef6f91eb..1b7aae6cdd82 100644
--- a/include/net/sctp/user.h
+++ b/include/net/sctp/user.h
@@ -560,9 +560,18 @@ struct sctp_paddrinfo {
 } __attribute__((packed, aligned(4)));
 
 /* Peer addresses's state. */
+/* UNKNOWN: Peer address passed by the upper layer in sendmsg or connect[x]
+ * calls.
+ * UNCONFIRMED: Peer address received in INIT/INIT-ACK address parameters.
+ *              Not yet confirmed by a heartbeat and not available for data
+ *              transfers.
+ * ACTIVE : Peer address confirmed, active and available for data transfers.
+ * INACTIVE: Peer address inactive and not available for data transfers.
+ */
 enum sctp_spinfo_state {
         SCTP_INACTIVE,
         SCTP_ACTIVE,
+        SCTP_UNCONFIRMED,
         SCTP_UNKNOWN = 0xffff  /* Value used for transport state unknown */
 };
 
diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index 9d05e13e92f6..27329ce9c311 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -441,7 +441,8 @@ void sctp_assoc_set_primary(struct sctp_association *asoc,
         /* If the primary path is changing, assume that the
          * user wants to use this new path.
          */
-        if (transport->state != SCTP_INACTIVE)
+        if ((transport->state == SCTP_ACTIVE) ||
+            (transport->state == SCTP_UNKNOWN))
                 asoc->peer.active_path = transport;
 
         /*
@@ -532,11 +533,11 @@ struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
         port = addr->v4.sin_port;
 
         SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_add_peer:association %p addr: ",
-                                 " port: %d state:%s\n",
+                                 " port: %d state:%d\n",
                                  asoc,
                                  addr,
                                  addr->v4.sin_port,
-                                 peer_state == SCTP_UNKNOWN?"UNKNOWN":"ACTIVE");
+                                 peer_state);
 
         /* Set the port if it has not been set yet.  */
         if (0 == asoc->peer.port)
@@ -545,9 +546,12 @@ struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
         /* Check to see if this is a duplicate. */
         peer = sctp_assoc_lookup_paddr(asoc, addr);
         if (peer) {
-                if (peer_state == SCTP_ACTIVE &&
-                    peer->state == SCTP_UNKNOWN)
-                     peer->state = SCTP_ACTIVE;
+                if (peer->state == SCTP_UNKNOWN) {
+                        if (peer_state == SCTP_ACTIVE)
+                                peer->state = SCTP_ACTIVE;
+                        if (peer_state == SCTP_UNCONFIRMED)
+                                peer->state = SCTP_UNCONFIRMED;
+                }
                 return peer;
         }
 
@@ -739,7 +743,8 @@ void sctp_assoc_control_transport(struct sctp_association *asoc,
         list_for_each(pos, &asoc->peer.transport_addr_list) {
                 t = list_entry(pos, struct sctp_transport, transports);
 
-                if (t->state == SCTP_INACTIVE)
+                if ((t->state == SCTP_INACTIVE) ||
+                    (t->state == SCTP_UNCONFIRMED))
                         continue;
                 if (!first || t->last_time_heard > first->last_time_heard) {
                         second = first;
@@ -759,7 +764,8 @@ void sctp_assoc_control_transport(struct sctp_association *asoc,
          * [If the primary is active but not most recent, bump the most
          * recently used transport.]
          */
-        if (asoc->peer.primary_path->state != SCTP_INACTIVE &&
+        if (((asoc->peer.primary_path->state == SCTP_ACTIVE) ||
+             (asoc->peer.primary_path->state == SCTP_UNKNOWN)) &&
             first != asoc->peer.primary_path) {
                 second = first;
                 first = asoc->peer.primary_path;
@@ -1054,7 +1060,7 @@ void sctp_assoc_update(struct sctp_association *asoc,
                                            transports);
                         if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr))
                                 sctp_assoc_add_peer(asoc, &trans->ipaddr,
-                                                    GFP_ATOMIC, SCTP_ACTIVE);
+                                                    GFP_ATOMIC, trans->state);
                 }
 
                 asoc->ctsn_ack_point = asoc->next_tsn - 1;
@@ -1094,7 +1100,8 @@ void sctp_assoc_update_retran_path(struct sctp_association *asoc)
 
                 /* Try to find an active transport. */
 
-                if (t->state != SCTP_INACTIVE) {
+                if ((t->state == SCTP_ACTIVE) ||
+                    (t->state == SCTP_UNKNOWN)) {
                         break;
                 } else {
                         /* Keep track of the next transport in case
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index e5faa351aaad..30b710c54e64 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -691,7 +691,8 @@ int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
 
                 if (!new_transport) {
                         new_transport = asoc->peer.active_path;
-                } else if (new_transport->state == SCTP_INACTIVE) {
+                } else if ((new_transport->state == SCTP_INACTIVE) ||
+                           (new_transport->state == SCTP_UNCONFIRMED)) {
                         /* If the chunk is Heartbeat or Heartbeat Ack,
                          * send it to chunk->transport, even if it's
                          * inactive.
@@ -848,7 +849,8 @@ int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
                          */
                         new_transport = chunk->transport;
                         if (!new_transport ||
-                            new_transport->state == SCTP_INACTIVE)
+                            ((new_transport->state == SCTP_INACTIVE) ||
+                             (new_transport->state == SCTP_UNCONFIRMED)))
                                 new_transport = asoc->peer.active_path;
 
                         /* Change packets if necessary.  */
@@ -1464,7 +1466,8 @@ static void sctp_check_transmitted(struct sctp_outq *q,
                         /* Mark the destination transport address as
                          * active if it is not so marked.
                          */
-                        if (transport->state == SCTP_INACTIVE) {
+                        if ((transport->state == SCTP_INACTIVE) ||
+                            (transport->state == SCTP_UNCONFIRMED)) {
                                 sctp_assoc_control_transport(
                                         transport->asoc,
                                         transport,
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 2a8773691695..8134e8b1cdca 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -2017,7 +2017,7 @@ static int sctp_process_param(struct sctp_association *asoc,
                 af->from_addr_param(&addr, param.addr, asoc->peer.port, 0);
                 scope = sctp_scope(peer_addr);
                 if (sctp_in_scope(&addr, scope))
-                        if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_ACTIVE))
+                        if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
                                 return 0;
                 break;
 
@@ -2418,7 +2418,7 @@ static __u16 sctp_process_asconf_param(struct sctp_association *asoc,
                  * Due to Resource Shortage'.
                  */
 
-                peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_ACTIVE);
+                peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
                 if (!peer)
                         return SCTP_ERROR_RSRC_LOW;
 
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index c5beb2ad7ef7..9c10bdec1afe 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -430,7 +430,11 @@ static void sctp_do_8_2_transport_strike(struct sctp_association *asoc,
         /* The check for association's overall error counter exceeding the
          * threshold is done in the state function.
          */
-        asoc->overall_error_count++;
+        /* When probing UNCONFIRMED addresses, the association overall
+         * error count is NOT incremented
+         */
+        if (transport->state != SCTP_UNCONFIRMED)
+                asoc->overall_error_count++;
 
         if (transport->state != SCTP_INACTIVE &&
             (transport->error_count++ >= transport->pathmaxrxt)) {
@@ -610,7 +614,7 @@ static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
         /* Mark the destination transport address as active if it is not so
          * marked.
          */
-        if (t->state == SCTP_INACTIVE)
+        if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED))
                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
                                              SCTP_HEARTBEAT_SUCCESS);
 
@@ -620,6 +624,10 @@ static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
          */
         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
+
+        /* Update the heartbeat timer.  */
+        if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
+                sctp_transport_hold(t);
 }
 
 /* Helper function to do a transport reset at the expiry of the hearbeat
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 9e58144f4851..e8498dce5335 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -846,6 +846,7 @@ static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep,
         hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t));
         hbinfo.daddr = transport->ipaddr;
         hbinfo.sent_at = jiffies;
+        hbinfo.hb_nonce = transport->hb_nonce;
 
         /* Send a heartbeat to our peer.  */
         paylen = sizeof(sctp_sender_hb_info_t);
@@ -1048,6 +1049,10 @@ sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep,
                 return SCTP_DISPOSITION_DISCARD;
         }
 
+        /* Validate the 64-bit random nonce. */
+        if (hbinfo->hb_nonce != link->hb_nonce)
+                return SCTP_DISPOSITION_DISCARD;
+
         max_interval = link->hbinterval + link->rto;
 
         /* Check if the timestamp looks valid.  */
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 160f62ad1cc5..2763aa93de1a 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -49,6 +49,7 @@
  */
 
 #include <linux/types.h>
+#include <linux/random.h>
 #include <net/sctp/sctp.h>
 #include <net/sctp/sm.h>
 
@@ -85,7 +86,6 @@ static struct sctp_transport *sctp_transport_init(struct sctp_transport *peer,
 
         peer->init_sent_count = 0;
 
-        peer->state = SCTP_ACTIVE;
         peer->param_flags = SPP_HB_DISABLE |
                             SPP_PMTUD_ENABLE |
                             SPP_SACKDELAY_ENABLE;
@@ -109,6 +109,9 @@ static struct sctp_transport *sctp_transport_init(struct sctp_transport *peer,
         peer->hb_timer.function = sctp_generate_heartbeat_event;
         peer->hb_timer.data = (unsigned long)peer;
 
+        /* Initialize the 64-bit random nonce sent with heartbeat. */
+        get_random_bytes(&peer->hb_nonce, sizeof(peer->hb_nonce));
+
         atomic_set(&peer->refcnt, 1);
         peer->dead = 0;
 
@@ -517,7 +520,9 @@ void sctp_transport_lower_cwnd(struct sctp_transport *transport,
 unsigned long sctp_transport_timeout(struct sctp_transport *t)
 {
         unsigned long timeout;
-        timeout = t->hbinterval + t->rto + sctp_jitter(t->rto);
+        timeout = t->rto + sctp_jitter(t->rto);
+        if (t->state != SCTP_UNCONFIRMED)
+                timeout += t->hbinterval;
         timeout += jiffies;
         return timeout;
 }