SCTP: handle COOKIE while in SHUTDOWN phase

This patch address the requirement to handle a COOKIE chunk whilst in
SHUTDOWN phase. The COOKIE shouldn't just be dropped but an OPERATION
ERROR chunk shall be sent to the peer to inform about the current
situation.

Change-Id: I1a47652402d49cfee3b0c810304d7902f3a62f40
Signed-off-by: Marco Varlese <marco.varlese@suse.com>

3 files changed, 40 insertions, 20 deletions

diff --git a/src/vnet/sctp/sctp.h b/src/vnet/sctp/sctp.h
index de5eb8f6685..815ca172adb 100644
--- a/src/vnet/sctp/sctp.h
+++ b/src/vnet/sctp/sctp.h
@@ -292,7 +292,9 @@ void sctp_prepare_abort_for_collision (sctp_connection_t * sctp_conn, u8 idx,
 				       vlib_buffer_t * b,
 				       ip4_address_t * ip4_addr,
 				       ip6_address_t * ip6_addr);
-
+void
+sctp_prepare_operation_error (sctp_connection_t * sctp_conn, u8 idx,
+			      vlib_buffer_t * b, u8 err_cause);
 void sctp_prepare_cookie_echo_chunk (sctp_connection_t * sctp_conn, u8 idx,
 				     vlib_buffer_t * b,
 				     sctp_state_cookie_param_t * sc);
diff --git a/src/vnet/sctp/sctp_input.c b/src/vnet/sctp/sctp_input.c
index 1863c89ef45..46a2100cc07 100644
--- a/src/vnet/sctp/sctp_input.c
+++ b/src/vnet/sctp/sctp_input.c
@@ -295,7 +295,8 @@ sctp_handle_operation_err (sctp_header_t * sctp_hdr,
       return SCTP_ERROR_INVALID_TAG;
     }
 
-  if (op_err->err_causes[0].cause_info == STALE_COOKIE_ERROR)
+  if (clib_net_to_host_u16 (op_err->err_causes[0].param_hdr.type) ==
+      STALE_COOKIE_ERROR)
     {
       if (sctp_conn->state != SCTP_STATE_COOKIE_ECHOED)
 	*next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
@@ -1350,6 +1351,12 @@ sctp46_shutdown_phase_inline (vlib_main_t * vm,
 					   &next0);
 	      break;
 
+	    case COOKIE_ECHO:	/* Cookie Received While Shutting Down */
+	      sctp_prepare_operation_error (sctp_conn, idx, b0,
+					    COOKIE_RECEIVED_WHILE_SHUTTING_DOWN);
+	      error0 = SCTP_ERROR_NONE;
+	      next0 = sctp_next_output (is_ip4);
+	      break;
 	      /* All UNEXPECTED scenarios (wrong chunk received per state-machine)
 	       * are handled by the input-dispatcher function using the table-lookup
 	       * hence we should never get to the "default" case below.
@@ -2132,9 +2139,13 @@ sctp46_input_dispatcher (vlib_main_t * vm, vlib_node_runtime_t * node,
 	  if (chunk_type >= UNKNOWN)
 	    {
 	      clib_warning
-		("Received an unrecognized chunk... something is really bad.");
+		("Received an unrecognized chunk; sending back OPERATION_ERROR chunk");
+
+	      sctp_prepare_operation_error (sctp_conn, MAIN_SCTP_SUB_CONN_IDX,
+					    b0, UNRECOGNIZED_CHUNK_TYPE);
+
 	      error0 = SCTP_ERROR_UNKOWN_CHUNK;
-	      next0 = SCTP_INPUT_NEXT_DROP;
+	      next0 = sctp_next_output (is_ip4);
 	      goto done;
 	    }
 
@@ -2387,7 +2398,8 @@ do {                                                       	\
     SCTP_ERROR_NONE);
   _(SHUTDOWN_PENDING, SHUTDOWN_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_ACK_CHUNK_VIOLATION);	/* UNEXPECTED SHUTDOWN_ACK chunk */
   _(SHUTDOWN_PENDING, OPERATION_ERROR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_OPERATION_ERROR_VIOLATION);	/* UNEXPECTED OPERATION_ERROR chunk */
-  _(SHUTDOWN_PENDING, COOKIE_ECHO, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_COOKIE_ECHO_VIOLATION);	/* UNEXPECTED COOKIE_ECHO chunk */
+  _(SHUTDOWN_PENDING, COOKIE_ECHO, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
+    SCTP_ERROR_NONE);
   _(SHUTDOWN_PENDING, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED COOKIE_ACK chunk */
   _(SHUTDOWN_PENDING, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);	/* UNEXPECTED ECNE chunk */
   _(SHUTDOWN_PENDING, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);	/* UNEXPECTED CWR chunk */
@@ -2405,7 +2417,8 @@ do {                                                       	\
   _(SHUTDOWN_SENT, SHUTDOWN, SCTP_INPUT_NEXT_SHUTDOWN_PHASE, SCTP_ERROR_NONE);
   _(SHUTDOWN_SENT, SHUTDOWN_ACK, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
     SCTP_ERROR_NONE);
-  _(SHUTDOWN_SENT, COOKIE_ECHO, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_COOKIE_ECHO_VIOLATION);	/* UNEXPECTED COOKIE_ECHO chunk */
+  _(SHUTDOWN_SENT, COOKIE_ECHO, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
+    SCTP_ERROR_NONE);
   _(SHUTDOWN_SENT, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED COOKIE_ACK chunk */
   _(SHUTDOWN_SENT, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);	/* UNEXPECTED ECNE chunk */
   _(SHUTDOWN_SENT, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);	/* UNEXPECTED CWR chunk */
@@ -2423,7 +2436,8 @@ do {                                                       	\
   _(SHUTDOWN_RECEIVED, SHUTDOWN, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_CHUNK_VIOLATION);	/* UNEXPECTED SHUTDOWN chunk */
   _(SHUTDOWN_RECEIVED, SHUTDOWN_ACK, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
     SCTP_ERROR_NONE);
-  _(SHUTDOWN_RECEIVED, COOKIE_ECHO, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_COOKIE_ECHO_VIOLATION);	/* UNEXPECTED COOKIE_ECHO chunk */
+  _(SHUTDOWN_RECEIVED, COOKIE_ECHO, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
+    SCTP_ERROR_NONE);
   _(SHUTDOWN_RECEIVED, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED COOKIE_ACK chunk */
   _(SHUTDOWN_RECEIVED, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);	/* UNEXPECTED ECNE chunk */
   _(SHUTDOWN_RECEIVED, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);	/* UNEXPECTED CWR chunk */
@@ -2440,7 +2454,8 @@ do {                                                       	\
   _(SHUTDOWN_ACK_SENT, ABORT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ABORT_CHUNK_VIOLATION);	/* UNEXPECTED ABORT chunk */
   _(SHUTDOWN_ACK_SENT, SHUTDOWN, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_CHUNK_VIOLATION);	/* UNEXPECTED SHUTDOWN chunk */
   _(SHUTDOWN_ACK_SENT, SHUTDOWN_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_ACK_CHUNK_VIOLATION);	/* UNEXPECTED SHUTDOWN_ACK chunk */
-  _(SHUTDOWN_ACK_SENT, COOKIE_ECHO, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_COOKIE_ECHO_VIOLATION);	/* UNEXPECTED COOKIE_ECHO chunk */
+  _(SHUTDOWN_ACK_SENT, COOKIE_ECHO, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
+    SCTP_ERROR_NONE);
   _(SHUTDOWN_ACK_SENT, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED COOKIE_ACK chunk */
   _(SHUTDOWN_ACK_SENT, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);	/* UNEXPECTED ECNE chunk */
   _(SHUTDOWN_ACK_SENT, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);	/* UNEXPECTED CWR chunk */
diff --git a/src/vnet/sctp/sctp_output.c b/src/vnet/sctp/sctp_output.c
index b7351275486..0c2fee1bb69 100644
--- a/src/vnet/sctp/sctp_output.c
+++ b/src/vnet/sctp/sctp_output.c
@@ -589,24 +589,23 @@ sctp_prepare_cookie_echo_chunk (sctp_connection_t * sctp_conn, u8 idx,
 }
 
 /**
- * Convert buffer to ABORT
+ * Convert buffer to ERROR
  */
-/*
 void
 sctp_prepare_operation_error (sctp_connection_t * sctp_conn, u8 idx,
-			      vlib_buffer_t * b, ip4_address_t * ip4_addr,
-			      ip6_address_t * ip6_addr)
+			      vlib_buffer_t * b, u8 err_cause)
 {
   vlib_main_t *vm = vlib_get_main ();
 
   sctp_reuse_buffer (vm, b);
 
-  // The minimum size of the message is given by the sctp_operation_error_t
-  u16 alloc_bytes = sizeof (sctp_operation_error_t);
+  /* The minimum size of the message is given by the sctp_operation_error_t */
+  u16 alloc_bytes =
+    sizeof (sctp_operation_error_t) + sizeof (sctp_err_cause_param_t);
 
-  // As per RFC 4960 the chunk_length value does NOT contemplate
-  // the size of the first header (see sctp_header_t) and any padding
-  //
+  /* As per RFC 4960 the chunk_length value does NOT contemplate
+   * the size of the first header (see sctp_header_t) and any padding
+   */
   u16 chunk_len = alloc_bytes - sizeof (sctp_header_t);
 
   alloc_bytes += vnet_sctp_calculate_padding (alloc_bytes);
@@ -614,13 +613,18 @@ sctp_prepare_operation_error (sctp_connection_t * sctp_conn, u8 idx,
   sctp_operation_error_t *err_chunk =
     vlib_buffer_push_uninit (b, alloc_bytes);
 
-  // src_port & dst_port are already in network byte-order
+  /* src_port & dst_port are already in network byte-order */
   err_chunk->sctp_hdr.checksum = 0;
   err_chunk->sctp_hdr.src_port = sctp_conn->sub_conn[idx].connection.lcl_port;
   err_chunk->sctp_hdr.dst_port = sctp_conn->sub_conn[idx].connection.rmt_port;
-  // As per RFC4960 Section 5.2.2: copy the INITIATE_TAG into the VERIFICATION_TAG of the ABORT chunk
+  /* As per RFC4960 Section 5.2.2: copy the INITIATE_TAG into the VERIFICATION_TAG of the ABORT chunk */
   err_chunk->sctp_hdr.verification_tag = sctp_conn->local_tag;
 
+  err_chunk->err_causes[0].param_hdr.length =
+    clib_host_to_net_u16 (sizeof (err_chunk->err_causes[0].param_hdr.type) +
+			  sizeof (err_chunk->err_causes[0].param_hdr.length));
+  err_chunk->err_causes[0].param_hdr.type = clib_host_to_net_u16 (err_cause);
+
   vnet_sctp_set_chunk_type (&err_chunk->chunk_hdr, OPERATION_ERROR);
   vnet_sctp_set_chunk_length (&err_chunk->chunk_hdr, chunk_len);
 
@@ -628,7 +632,6 @@ sctp_prepare_operation_error (sctp_connection_t * sctp_conn, u8 idx,
     sctp_conn->sub_conn[idx].connection.c_index;
   vnet_buffer (b)->sctp.subconn_idx = idx;
 }
-*/
 
 /**
  * Convert buffer to ABORT