flow: Common address information for target side

Require the address and port information for the target (non
initiating) side to be populated when a flow enters TGT state.
Implement that for TCP and ICMP.  For now this leaves some information
redundantly recorded in both generic and type specific fields.  We'll
fix that in later patches.

For TCP we now use the information from the flow to construct the
destination socket address in both tcp_conn_from_tap() and
tcp_splice_connect().

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 44 insertions, 38 deletions

diff --git a/tcp.c b/tcp.c
index 286a417..914a074 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1647,18 +1647,10 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
 {
 	in_port_t srcport = ntohs(th->source);
 	in_port_t dstport = ntohs(th->dest);
-	struct sockaddr_in addr4 = {
-		.sin_family = AF_INET,
-		.sin_port = htons(dstport),
-		.sin_addr = *(struct in_addr *)daddr,
-	};
-	struct sockaddr_in6 addr6 = {
-		.sin6_family = AF_INET6,
-		.sin6_port = htons(dstport),
-		.sin6_addr = *(struct in6_addr *)daddr,
-	};
-	const struct sockaddr *sa;
+	const struct flowside *ini, *tgt;
 	struct tcp_tap_conn *conn;
+	union inany_addr dstaddr; /* FIXME: Avoid bulky temporary */
+	union sockaddr_inany sa;
 	union flow *flow;
 	int s = -1, mss;
 	socklen_t sl;
@@ -1666,9 +1658,22 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
 	if (!(flow = flow_alloc()))
 		return;
 
-	flow_initiate_af(flow, PIF_TAP, af, saddr, srcport, daddr, dstport);
+	ini = flow_initiate_af(flow, PIF_TAP,
+			       af, saddr, srcport, daddr, dstport);
+
+	dstaddr = ini->faddr;
+	if (!c->no_map_gw) {
+		if (inany_equals4(&dstaddr, &c->ip4.gw))
+			dstaddr = inany_loopback4;
+		else if (inany_equals6(&dstaddr, &c->ip6.gw))
+			dstaddr = inany_loopback6;
+
+	}
 
-	flow_target(flow, PIF_HOST);
+	/* FIXME: Record outbound source address when known */
+	tgt = flow_target_af(flow, PIF_HOST, AF_INET6,
+			     NULL, 0, /* Kernel decides source address */
+			     &dstaddr, dstport);
 	conn = FLOW_SET_TYPE(flow, FLOW_TCP, tcp);
 
 	if (af == AF_INET) {
@@ -1687,9 +1692,6 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
 			      dstport);
 			goto cancel;
 		}
-
-		sa = (struct sockaddr *)&addr4;
-		sl = sizeof(addr4);
 	} else if (af == AF_INET6) {
 		if (IN6_IS_ADDR_UNSPECIFIED(saddr) ||
 		    IN6_IS_ADDR_MULTICAST(saddr) || srcport == 0 ||
@@ -1704,9 +1706,6 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
 			      dstport);
 			goto cancel;
 		}
-
-		sa = (struct sockaddr *)&addr6;
-		sl = sizeof(addr6);
 	} else {
 		ASSERT(0);
 	}
@@ -1714,12 +1713,7 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
 	if ((s = tcp_conn_sock(c, af)) < 0)
 		goto cancel;
 
-	if (!c->no_map_gw) {
-		if (af == AF_INET && IN4_ARE_ADDR_EQUAL(daddr, &c->ip4.gw))
-			addr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
-		if (af == AF_INET6 && IN6_ARE_ADDR_EQUAL(daddr, &c->ip6.gw))
-			addr6.sin6_addr	= in6addr_loopback;
-	}
+	pif_sockaddr(c, &sa, &sl, PIF_HOST, &tgt->eaddr, tgt->eport);
 
 	/* Use bind() to check if the target address is local (EADDRINUSE or
 	 * similar) and already bound, and set the LOCAL flag in that case.
@@ -1731,7 +1725,7 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
 	 *
 	 * So, if bind() succeeds, close the socket, get a new one, and proceed.
 	 */
-	if (bind(s, sa, sl)) {
+	if (bind(s, &sa.sa, sl)) {
 		if (errno != EADDRNOTAVAIL && errno != EACCES)
 			conn_flag(c, conn, LOCAL);
 	} else {
@@ -1741,7 +1735,7 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
 			goto cancel;
 	}
 
-	if (af == AF_INET6 && IN6_IS_ADDR_LINKLOCAL(&addr6.sin6_addr)) {
+	if (inany_is_linklocal6(&tgt->eaddr)) {
 		struct sockaddr_in6 addr6_ll = {
 			.sin6_family = AF_INET6,
 			.sin6_addr = c->ip6.addr_ll,
@@ -1749,6 +1743,8 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
 		};
 		if (bind(s, (struct sockaddr *)&addr6_ll, sizeof(addr6_ll)))
 			goto cancel;
+	} else if (!inany_is_loopback(&tgt->eaddr)) {
+		tcp_bind_outbound(c, s, af);
 	}
 
 	conn->sock = s;
@@ -1784,12 +1780,7 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
 
 	tcp_hash_insert(c, conn);
 
-	if ((af == AF_INET &&  !IN4_IS_ADDR_LOOPBACK(&addr4.sin_addr)) ||
-	    (af == AF_INET6 && !IN6_IS_ADDR_LOOPBACK(&addr6.sin6_addr) &&
-			       !IN6_IS_ADDR_LINKLOCAL(&addr6.sin6_addr)))
-		tcp_bind_outbound(c, s, af);
-
-	if (connect(s, sa, sl)) {
+	if (connect(s, &sa.sa, sl)) {
 		if (errno != EINPROGRESS) {
 			tcp_rst(c, conn);
 			goto cancel;
@@ -2297,9 +2288,25 @@ static void tcp_tap_conn_from_sock(struct ctx *c, in_port_t dstport,
 				   const union sockaddr_inany *sa,
 				   const struct timespec *now)
 {
+	union inany_addr saddr, daddr; /* FIXME: avoid bulky temporaries */
 	struct tcp_tap_conn *conn;
+	in_port_t srcport;
+
+	inany_from_sockaddr(&saddr, &srcport, sa);
+	tcp_snat_inbound(c, &saddr);
 
-	flow_target(flow, PIF_TAP);
+	if (inany_v4(&saddr)) {
+		daddr = inany_from_v4(c->ip4.addr_seen);
+	} else {
+		if (inany_is_linklocal6(&saddr))
+			daddr.a6 = c->ip6.addr_ll_seen;
+		else
+			daddr.a6 = c->ip6.addr_seen;
+	}
+	dstport += c->tcp.fwd_in.delta[dstport];
+
+	flow_target_af(flow,  PIF_TAP, AF_INET6,
+		       &saddr, srcport, &daddr, dstport);
 	conn = FLOW_SET_TYPE(flow, FLOW_TCP, tcp);
 
 	conn->sock = s;
@@ -2307,10 +2314,9 @@ static void tcp_tap_conn_from_sock(struct ctx *c, in_port_t dstport,
 	conn->ws_to_tap = conn->ws_from_tap = 0;
 	conn_event(c, conn, SOCK_ACCEPTED);
 
-	inany_from_sockaddr(&conn->faddr, &conn->fport, sa);
-	conn->eport = dstport + c->tcp.fwd_in.delta[dstport];
-
-	tcp_snat_inbound(c, &conn->faddr);
+	conn->faddr = saddr;
+	conn->fport = srcport;
+	conn->eport = dstport;
 
 	tcp_seq_init(c, conn, now);
 	tcp_hash_insert(c, conn);