sctp: deal with multiple COOKIE_ECHO chunks

Attempt to reduce the number of IP packets emitted in response to single
SCTP packet (2e3216cd) introduced a complication - if a packet contains
two COOKIE_ECHO chunks and nothing else then SCTP state machine corks the
socket while processing first COOKIE_ECHO and then loses the association
and forgets to uncork the socket. To deal with the issue add new SCTP
command which can be used to set association explictly. Use this new
command when processing second COOKIE_ECHO chunk to restore the context
for SCTP state machine.

Signed-off-by: Max Matveev <makc@redhat.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 6506458ccd33bbc3df02f76f8ae661c2fafd18d9..712b3bebeda78dbb2d3dbb2387fd15f3dd6b82ac 100644 (file)
--- a/include/net/sctp/command.h
+++ b/include/net/sctp/command.h
@@ -109,6 +109,7 @@ typedef enum {
        SCTP_CMD_SEND_MSG,       /* Send the whole use message */
        SCTP_CMD_SEND_NEXT_ASCONF, /* Send the next ASCONF after ACK */
        SCTP_CMD_PURGE_ASCONF_QUEUE, /* Purge all asconf queues.*/
+       SCTP_CMD_SET_ASOC,       /* Restore association context */
        SCTP_CMD_LAST
 } sctp_verb_t;
 

diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index 167c880cf8da45240932d6fce85f43e9f2c71ddb..76388b083f283a2e2c62ab3f605ee8a12469454f 100644 (file)
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -1689,6 +1689,11 @@ static int sctp_cmd_interpreter(sctp_event_t event_type,
                case SCTP_CMD_PURGE_ASCONF_QUEUE:
                        sctp_asconf_queue_teardown(asoc);
                        break;
+
+               case SCTP_CMD_SET_ASOC:
+                       asoc = cmd->obj.asoc;
+                       break;
+
                default:
                        pr_warn("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 49b847b00f9956cc1eea2d5077bdcbff1b3a3285..a0f31e6c1c63c1c44e0c3a27a62b0a36f6dc55b4 100644 (file)
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -2047,6 +2047,12 @@ sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep,
        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 
+       /* Restore association pointer to provide SCTP command interpeter
+        * with a valid context in case it needs to manipulate
+        * the queues */
+       sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
+                        SCTP_ASOC((struct sctp_association *)asoc));
+
        return retval;
 
 nomem: