[SCTP]: Set assoc_id correctly during INIT collision.

During the INIT/COOKIE-ACK collision cases, it's possible to get
into a situation where the association id is not yet set at the time
of the user event generation.  As a result, user events have an
association id set to 0 which will confuse applications.

This happens if we hit case B of duplicate cookie processing.
In the particular example found and provided by Oscar Isaula
<Oscar.Isaula@motorola.com>, flow looks like this:
A				B
---- INIT------->  (lost)
	    <---------INIT------
---- INIT-ACK--->
	    <------ Cookie ECHO

When the Cookie Echo is received, we end up trying to update the
association that was created on A as a result of the (lost) INIT,
but that association doesn't have the ID set yet.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/sctp/command.h b/include/net/sctp/command.h
index 6114c4f..f56c8d6 100644 (file)
--- a/include/net/sctp/command.h
+++ b/include/net/sctp/command.h
@@ -100,6 +100,8 @@ typedef enum {
        SCTP_CMD_T3_RTX_TIMERS_STOP, /* Stops T3-rtx pending timers */
        SCTP_CMD_FORCE_PRIM_RETRAN,  /* Forces retrans. over primary path. */
        SCTP_CMD_SET_SK_ERR,     /* Set sk_err */
+       SCTP_CMD_ASSOC_CHANGE,   /* generate and send assoc_change event */
+       SCTP_CMD_ADAPTATION_IND, /* generate and send adaptation event */
        SCTP_CMD_LAST
 } sctp_verb_t;
 

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 7b4fff9..5e81984 100644 (file)
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -1857,6 +1857,7 @@ int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *,
 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
                                         struct sctp_cookie*,
                                         gfp_t gfp);
+int sctp_assoc_set_id(struct sctp_association *, gfp_t);
 
 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
                        const union sctp_addr *ss2);

diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index db73ef9..df94e3c 100644 (file)
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -1103,6 +1103,13 @@ void sctp_assoc_update(struct sctp_association *asoc,
                        asoc->ssnmap = new->ssnmap;
                        new->ssnmap = NULL;
                }
+
+               if (!asoc->assoc_id) {
+                       /* get a new association id since we don't have one
+                        * yet.
+                        */
+                       sctp_assoc_set_id(asoc, GFP_ATOMIC);
+               }
        }
 }
 
@@ -1375,3 +1382,25 @@ out:
        sctp_read_unlock(&asoc->base.addr_lock);
        return found;
 }
+
+/* Set an association id for a given association */
+int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp)
+{
+       int assoc_id;
+       int error = 0;
+retry:
+       if (unlikely(!idr_pre_get(&sctp_assocs_id, gfp)))
+               return -ENOMEM;
+
+       spin_lock_bh(&sctp_assocs_id_lock);
+       error = idr_get_new_above(&sctp_assocs_id, (void *)asoc,
+                                   1, &assoc_id);
+       spin_unlock_bh(&sctp_assocs_id_lock);
+       if (error == -EAGAIN)
+               goto retry;
+       else if (error)
+               return error;
+
+       asoc->assoc_id = (sctp_assoc_t) assoc_id;
+       return error;
+}

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index be783a3..8d18f57 100644 (file)
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -1939,7 +1939,6 @@ int sctp_process_init(struct sctp_association *asoc, sctp_cid_t cid,
         * association.
         */
        if (!asoc->temp) {
-               int assoc_id;
                int error;
 
                asoc->ssnmap = sctp_ssnmap_new(asoc->c.sinit_max_instreams,
@@ -1947,19 +1946,9 @@ int sctp_process_init(struct sctp_association *asoc, sctp_cid_t cid,
                if (!asoc->ssnmap)
                        goto clean_up;
 
-       retry:
-               if (unlikely(!idr_pre_get(&sctp_assocs_id, gfp)))
+               error = sctp_assoc_set_id(asoc, gfp);
+               if (error)
                        goto clean_up;
-               spin_lock_bh(&sctp_assocs_id_lock);
-               error = idr_get_new_above(&sctp_assocs_id, (void *)asoc, 1,
-                                         &assoc_id);
-               spin_unlock_bh(&sctp_assocs_id_lock);
-               if (error == -EAGAIN)
-                       goto retry;
-               else if (error)
-                       goto clean_up;
-
-               asoc->assoc_id = (sctp_assoc_t) assoc_id;
        }
 
        /* ADDIP Section 4.1 ASCONF Chunk Procedures

diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index b37a7ad..d9fad4f 100644 (file)
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -862,6 +862,33 @@ static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
                sk->sk_err = error;
 }
 
+/* Helper function to generate an association change event */
+static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
+                                struct sctp_association *asoc,
+                                u8 state)
+{
+       struct sctp_ulpevent *ev;
+
+       ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
+                                           asoc->c.sinit_num_ostreams,
+                                           asoc->c.sinit_max_instreams,
+                                           NULL, GFP_ATOMIC);
+       if (ev)
+               sctp_ulpq_tail_event(&asoc->ulpq, ev);
+}
+
+/* Helper function to generate an adaptation indication event */
+static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
+                                   struct sctp_association *asoc)
+{
+       struct sctp_ulpevent *ev;
+
+       ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
+
+       if (ev)
+               sctp_ulpq_tail_event(&asoc->ulpq, ev);
+}
+
 /* These three macros allow us to pull the debugging code out of the
  * main flow of sctp_do_sm() to keep attention focused on the real
  * functionality there.
@@ -1485,6 +1512,14 @@ static int sctp_cmd_interpreter(sctp_event_t event_type,
                case SCTP_CMD_SET_SK_ERR:
                        sctp_cmd_set_sk_err(asoc, cmd->obj.error);
                        break;
+               case SCTP_CMD_ASSOC_CHANGE:
+                       sctp_cmd_assoc_change(commands, asoc,
+                                             cmd->obj.u8);
+                       break;
+               case SCTP_CMD_ADAPTATION_IND:
+                       sctp_cmd_adaptation_ind(commands, asoc);
+                       break;
+
                default:
                        printk(KERN_WARNING "Impossible command: %u, %p\n",
                               cmd->verb, cmd->obj.ptr);

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 9e28a5d..f02ce3d 100644 (file)
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -1656,7 +1656,6 @@ static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep,
                                        struct sctp_association *new_asoc)
 {
        sctp_init_chunk_t *peer_init;
-       struct sctp_ulpevent *ev;
        struct sctp_chunk *repl;
 
        /* new_asoc is a brand-new association, so these are not yet
@@ -1687,34 +1686,28 @@ static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep,
         * D) IMPLEMENTATION NOTE: An implementation may choose to
         * send the Communication Up notification to the SCTP user
         * upon reception of a valid COOKIE ECHO chunk.
+        *
+        * Sadly, this needs to be implemented as a side-effect, because
+        * we are not guaranteed to have set the association id of the real
+        * association and so these notifications need to be delayed until
+        * the association id is allocated.
         */
-       ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 0,
-                                            new_asoc->c.sinit_num_ostreams,
-                                            new_asoc->c.sinit_max_instreams,
-                                            NULL, GFP_ATOMIC);
-       if (!ev)
-               goto nomem_ev;
 
-       sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
+       sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
 
        /* Sockets API Draft Section 5.3.1.6
         * When a peer sends a Adaptation Layer Indication parameter , SCTP
         * delivers this notification to inform the application that of the
         * peers requested adaptation layer.
+        *
+        * This also needs to be done as a side effect for the same reason as
+        * above.
         */
-       if (asoc->peer.adaptation_ind) {
-               ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
-               if (!ev)
-                       goto nomem_ev;
-
-               sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
-                               SCTP_ULPEVENT(ev));
-       }
+       if (asoc->peer.adaptation_ind)
+               sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
 
        return SCTP_DISPOSITION_CONSUME;
 
-nomem_ev:
-       sctp_chunk_free(repl);
 nomem:
        return SCTP_DISPOSITION_NOMEM;
 }