sctp: Add ASCONF operation on the single-homed host

In this case, the SCTP association transmits an ASCONF packet
including addition of the new IP address and deletion of the old
address.  This patch implements this functionality.
In this case, the ASCONF chunk is added to the beginning of the
queue, because the other chunks cannot be transmitted in this state.

Signed-off-by: Michio Honda <micchie@sfc.wide.ad.jp>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Acked-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 13 insertions, 0 deletions

diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 1c88c8911dc5..edc753297a49 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -754,6 +754,16 @@ static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
          */
 
         list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
+                /* RFC 5061, 5.3
+                 * F1) This means that until such time as the ASCONF
+                 * containing the add is acknowledged, the sender MUST
+                 * NOT use the new IP address as a source for ANY SCTP
+                 * packet except on carrying an ASCONF Chunk.
+                 */
+                if (asoc->src_out_of_asoc_ok &&
+                    chunk->chunk_hdr->type != SCTP_CID_ASCONF)
+                        continue;
+
                 list_del_init(&chunk->list);
 
                 /* Pick the right transport to use. */
@@ -881,6 +891,9 @@ static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
                 }
         }
 
+        if (q->asoc->src_out_of_asoc_ok)
+                goto sctp_flush_out;
+
         /* Is it OK to send data chunks?  */
         switch (asoc->state) {
         case SCTP_STATE_COOKIE_ECHOED: