[PATCH v3 18/20] tcp: Get our socket port using getsockname() when connecting from guest

[Stefano Brivio <sbrivio@redhat.com>]

For migration only: we need to store 'oport', our socket-side port,
as we establish a connection from the guest, so that we can bind the
same oport as source port in the migration target.

Use getsockname() to fetch that.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
 flow.c       |  4 ++--
 flow_table.h |  4 ++--
 tcp.c        | 24 +++++++++++++++++++++++-
 3 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/flow.c b/flow.c
index 5638ff1..506cbac 100644
--- a/flow.c
+++ b/flow.c
@@ -411,8 +411,8 @@ const struct flowside *flow_initiate_sa(union flow *flow, uint8_t pif,
  *
  * Return: pointer to the target flowside information
  */
-const struct flowside *flow_target(const struct ctx *c, union flow *flow,
-				   uint8_t proto)
+struct flowside *flow_target(const struct ctx *c, union flow *flow,
+			     uint8_t proto)
 {
 	char estr[INANY_ADDRSTRLEN], fstr[INANY_ADDRSTRLEN];
 	struct flow_common *f = &flow->f;
diff --git a/flow_table.h b/flow_table.h
index 633805d..b107107 100644
--- a/flow_table.h
+++ b/flow_table.h
@@ -178,8 +178,8 @@ const struct flowside *flow_target_af(union flow *flow, uint8_t pif,
 				      sa_family_t af,
 				      const void *saddr, in_port_t sport,
 				      const void *daddr, in_port_t dport);
-const struct flowside *flow_target(const struct ctx *c, union flow *flow,
-				   uint8_t proto);
+struct flowside *flow_target(const struct ctx *c, union flow *flow,
+			     uint8_t proto);
 
 union flow *flow_set_type(union flow *flow, enum flow_type type);
 #define FLOW_SET_TYPE(flow_, t_, var_)	(&flow_set_type((flow_), (t_))->var_)
diff --git a/tcp.c b/tcp.c
index 0bd2a02..4fd405b 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1471,6 +1471,8 @@ static void tcp_bind_outbound(const struct ctx *c,
  * @opts:	Pointer to start of options
  * @optlen:	Bytes in options: caller MUST ensure available length
  * @now:	Current timestamp
+ *
+ * #syscalls:vu getsockname
  */
 static void tcp_conn_from_tap(const struct ctx *c, sa_family_t af,
 			      const void *saddr, const void *daddr,
@@ -1479,9 +1481,10 @@ static void tcp_conn_from_tap(const struct ctx *c, sa_family_t af,
 {
 	in_port_t srcport = ntohs(th->source);
 	in_port_t dstport = ntohs(th->dest);
-	const struct flowside *ini, *tgt;
+	const struct flowside *ini;
 	struct tcp_tap_conn *conn;
 	union sockaddr_inany sa;
+	struct flowside *tgt;
 	union flow *flow;
 	int s = -1, mss;
 	uint64_t hash;
@@ -1586,6 +1589,25 @@ static void tcp_conn_from_tap(const struct ctx *c, sa_family_t af,
 	}
 
 	tcp_epoll_ctl(c, conn);
+
+	if (c->mode == MODE_VU) { /* To rebind to same oport after migration */
+		if (af == AF_INET) {
+			struct sockaddr_in s_in;
+			socklen_t sl;
+
+			sl = sizeof(s_in);
+			getsockname(s, (struct sockaddr *)&s_in, &sl);
+			tgt->oport = ntohs(s_in.sin_port);
+		} else {
+			struct sockaddr_in6 s_in6;
+			socklen_t sl;
+
+			sl = sizeof(s_in6);
+			getsockname(s, (struct sockaddr *)&s_in6, &sl);
+			tgt->oport = ntohs(s_in6.sin6_port);
+		}
+	}
+
 	FLOW_ACTIVATE(conn);
 	return;
 
-- 
@@ -1471,6 +1471,8 @@ static void tcp_bind_outbound(const struct ctx *c,
  * @opts:	Pointer to start of options
  * @optlen:	Bytes in options: caller MUST ensure available length
  * @now:	Current timestamp
+ *
+ * #syscalls:vu getsockname
  */
 static void tcp_conn_from_tap(const struct ctx *c, sa_family_t af,
 			      const void *saddr, const void *daddr,
@@ -1479,9 +1481,10 @@ static void tcp_conn_from_tap(const struct ctx *c, sa_family_t af,
 {
 	in_port_t srcport = ntohs(th->source);
 	in_port_t dstport = ntohs(th->dest);
-	const struct flowside *ini, *tgt;
+	const struct flowside *ini;
 	struct tcp_tap_conn *conn;
 	union sockaddr_inany sa;
+	struct flowside *tgt;
 	union flow *flow;
 	int s = -1, mss;
 	uint64_t hash;
@@ -1586,6 +1589,25 @@ static void tcp_conn_from_tap(const struct ctx *c, sa_family_t af,
 	}
 
 	tcp_epoll_ctl(c, conn);
+
+	if (c->mode == MODE_VU) { /* To rebind to same oport after migration */
+		if (af == AF_INET) {
+			struct sockaddr_in s_in;
+			socklen_t sl;
+
+			sl = sizeof(s_in);
+			getsockname(s, (struct sockaddr *)&s_in, &sl);
+			tgt->oport = ntohs(s_in.sin_port);
+		} else {
+			struct sockaddr_in6 s_in6;
+			socklen_t sl;
+
+			sl = sizeof(s_in6);
+			getsockname(s, (struct sockaddr *)&s_in6, &sl);
+			tgt->oport = ntohs(s_in6.sin6_port);
+		}
+	}
+
 	FLOW_ACTIVATE(conn);
 	return;
 
-- 
2.43.0