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, 50 insertions, 6 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index cc06198dc444..e7e1b142875c 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -583,10 +583,6 @@ static int sctp_send_asconf_add_ip(struct sock		*sk,
 			goto out;
 		}
 
-		retval = sctp_send_asconf(asoc, chunk);
-		if (retval)
-			goto out;
-
 		/* Add the new addresses to the bind address list with
 		 * use_as_src set to 0.
 		 */
@@ -599,6 +595,23 @@ static int sctp_send_asconf_add_ip(struct sock		*sk,
 						    SCTP_ADDR_NEW, GFP_ATOMIC);
 			addr_buf += af->sockaddr_len;
 		}
+		if (asoc->src_out_of_asoc_ok) {
+			struct sctp_transport *trans;
+
+			list_for_each_entry(trans,
+			    &asoc->peer.transport_addr_list, transports) {
+				/* Clear the source and route cache */
+				dst_release(trans->dst);
+				trans->cwnd = min(4*asoc->pathmtu, max_t(__u32,
+				    2*asoc->pathmtu, 4380));
+				trans->ssthresh = asoc->peer.i.a_rwnd;
+				trans->rto = asoc->rto_initial;
+				trans->rtt = trans->srtt = trans->rttvar = 0;
+				sctp_transport_route(trans, NULL,
+				    sctp_sk(asoc->base.sk));
+			}
+		}
+		retval = sctp_send_asconf(asoc, chunk);
 	}
 
 out:
@@ -715,7 +728,9 @@ static int sctp_send_asconf_del_ip(struct sock		*sk,
 	struct sctp_sockaddr_entry *saddr;
 	int 			i;
 	int 			retval = 0;
+	int			stored = 0;
 
+	chunk = NULL;
 	if (!sctp_addip_enable)
 		return retval;
 
@@ -766,8 +781,33 @@ static int sctp_send_asconf_del_ip(struct sock		*sk,
 		bp = &asoc->base.bind_addr;
 		laddr = sctp_find_unmatch_addr(bp, (union sctp_addr *)addrs,
 					       addrcnt, sp);
-		if (!laddr)
-			continue;
+		if ((laddr == NULL) && (addrcnt == 1)) {
+			if (asoc->asconf_addr_del_pending)
+				continue;
+			asoc->asconf_addr_del_pending =
+			    kzalloc(sizeof(union sctp_addr), GFP_ATOMIC);
+			asoc->asconf_addr_del_pending->sa.sa_family =
+				    addrs->sa_family;
+			asoc->asconf_addr_del_pending->v4.sin_port =
+				    htons(bp->port);
+			if (addrs->sa_family == AF_INET) {
+				struct sockaddr_in *sin;
+
+				sin = (struct sockaddr_in *)addrs;
+				asoc->asconf_addr_del_pending->v4.sin_addr.s_addr = sin->sin_addr.s_addr;
+			} else if (addrs->sa_family == AF_INET6) {
+				struct sockaddr_in6 *sin6;
+
+				sin6 = (struct sockaddr_in6 *)addrs;
+				ipv6_addr_copy(&asoc->asconf_addr_del_pending->v6.sin6_addr, &sin6->sin6_addr);
+			}
+			SCTP_DEBUG_PRINTK_IPADDR("send_asconf_del_ip: keep the last address asoc: %p ",
+			    " at %p\n", asoc, asoc->asconf_addr_del_pending,
+			    asoc->asconf_addr_del_pending);
+			asoc->src_out_of_asoc_ok = 1;
+			stored = 1;
+			goto skip_mkasconf;
+		}
 
 		/* We do not need RCU protection throughout this loop
 		 * because this is done under a socket lock from the
@@ -780,6 +820,7 @@ static int sctp_send_asconf_del_ip(struct sock		*sk,
 			goto out;
 		}
 
+skip_mkasconf:
 		/* Reset use_as_src flag for the addresses in the bind address
 		 * list that are to be deleted.
 		 */
@@ -805,6 +846,9 @@ static int sctp_send_asconf_del_ip(struct sock		*sk,
 					     sctp_sk(asoc->base.sk));
 		}
 
+		if (stored)
+			/* We don't need to transmit ASCONF */
+			continue;
 		retval = sctp_send_asconf(asoc, chunk);
 	}
 out: