SCTP: Handle a COOKIE ECHO/ACK when a TCB Exists

This patch addresses the requirements depicted in section 5.2.4 of the
RFC 4960. It also takes care of handling the ERROR chunk and obviously
the STALE COOKIE error.

Change-Id: I6b88a9371546b18a52abac22f7c593a5f16be838
Signed-off-by: Marco Varlese <marco.varlese@suse.com>

1 files changed, 42 insertions, 0 deletions

diff --git a/src/vnet/sctp/sctp_output.c b/src/vnet/sctp/sctp_output.c
index e44451c034c..5e64ca792af 100644
--- a/src/vnet/sctp/sctp_output.c
+++ b/src/vnet/sctp/sctp_output.c
@@ -591,6 +591,48 @@ sctp_prepare_cookie_echo_chunk (sctp_connection_t * sctp_conn, u8 idx,
 /**
  * Convert buffer to ABORT
  */
+/*
+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_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);
+
+  // 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);
+
+  sctp_operation_error_t *err_chunk =
+    vlib_buffer_push_uninit (b, alloc_bytes);
+
+  // 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
+  err_chunk->sctp_hdr.verification_tag = sctp_conn->local_tag;
+
+  vnet_sctp_set_chunk_type (&err_chunk->chunk_hdr, OPERATION_ERROR);
+  vnet_sctp_set_chunk_length (&err_chunk->chunk_hdr, chunk_len);
+
+  vnet_buffer (b)->sctp.connection_index =
+    sctp_conn->sub_conn[idx].connection.c_index;
+  vnet_buffer (b)->sctp.subconn_idx = idx;
+}
+*/
+
+/**
+ * Convert buffer to ABORT
+ */
 void
 sctp_prepare_abort_for_collision (sctp_connection_t * sctp_conn, u8 idx,
 				  vlib_buffer_t * b, ip4_address_t * ip4_addr,