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path: root/tcp.c
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Diffstat (limited to 'tcp.c')
-rw-r--r--tcp.c48
1 files changed, 31 insertions, 17 deletions
diff --git a/tcp.c b/tcp.c
index 6852423..a2e81d5 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1631,6 +1631,9 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
flow_initiate(flow, PIF_TAP);
+ flow_target(flow, PIF_HOST);
+ conn = FLOW_SET_TYPE(flow, FLOW_TCP, tcp);
+
if (af == AF_INET) {
if (IN4_IS_ADDR_UNSPECIFIED(saddr) ||
IN4_IS_ADDR_BROADCAST(saddr) ||
@@ -1647,6 +1650,9 @@ 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 ||
@@ -1661,6 +1667,11 @@ 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);
}
if ((s = tcp_conn_sock(c, af)) < 0)
@@ -1673,6 +1684,26 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
addr6.sin6_addr = in6addr_loopback;
}
+ /* Use bind() to check if the target address is local (EADDRINUSE or
+ * similar) and already bound, and set the LOCAL flag in that case.
+ *
+ * If bind() succeeds, in general, we could infer that nobody (else) is
+ * listening on that address and port and reset the connection attempt
+ * early, but we can't rely on that if non-local binds are enabled,
+ * because bind() would succeed for any non-local address we can reach.
+ *
+ * So, if bind() succeeds, close the socket, get a new one, and proceed.
+ */
+ if (bind(s, sa, sl)) {
+ if (errno != EADDRNOTAVAIL && errno != EACCES)
+ conn_flag(c, conn, LOCAL);
+ } else {
+ /* Not a local, bound destination, inconclusive test */
+ close(s);
+ if ((s = tcp_conn_sock(c, af)) < 0)
+ goto cancel;
+ }
+
if (af == AF_INET6 && IN6_IS_ADDR_LINKLOCAL(&addr6.sin6_addr)) {
struct sockaddr_in6 addr6_ll = {
.sin6_family = AF_INET6,
@@ -1683,8 +1714,6 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
goto cancel;
}
- flow_target(flow, PIF_HOST);
- conn = FLOW_SET_TYPE(flow, FLOW_TCP, tcp);
conn->sock = s;
conn->timer = -1;
conn_event(c, conn, TAP_SYN_RCVD);
@@ -1706,14 +1735,6 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
inany_from_af(&conn->faddr, af, daddr);
- if (af == AF_INET) {
- sa = (struct sockaddr *)&addr4;
- sl = sizeof(addr4);
- } else {
- sa = (struct sockaddr *)&addr6;
- sl = sizeof(addr6);
- }
-
conn->fport = dstport;
conn->eport = srcport;
@@ -1726,13 +1747,6 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
tcp_hash_insert(c, conn);
- if (!bind(s, sa, sl)) {
- tcp_rst(c, conn); /* Nobody is listening then */
- goto cancel;
- }
- if (errno != EADDRNOTAVAIL && errno != EACCES)
- conn_flag(c, conn, LOCAL);
-
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)))