[PATCH] pasta: fix tcp port forwarding in auto mode

20 Mar 2023

The logic in tcp_timer() was inverted. fwd_out should expose the host
ports in the ns. Therfore it must read the ports on the host and then
bind them in the netns. The same for fwd_in which checks ports in the
ns and then exposes them on the host.

Note that this only fixes tcp ports, udp does not seems to work at all
right now with the auto mode.

Signed-off-by: Paul Holzinger 
---
 tcp.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/tcp.c b/tcp.c
index 0214087..0d0ad13 100644
--- a/tcp.c
+++ b/tcp.c
@@ -89,7 +89,7 @@
  * No port translation is needed for connections initiated remotely or by the
  * local host: source port from socket is reused while establishing connections
  * to the guest.
- * 
+ *
  * For connections initiated by the guest, it's not possible to force the same
  * source port as connections are established by the host kernel: that's the
  * only port translation needed.
@@ -173,7 +173,7 @@
  *   new socket is created and mapped in connection tracking table, setting
  *   MSS and window clamping from header and option of the observed SYN segment
  *
- * 
+ *
  * Aging and timeout
  * -----------------
  *
@@ -560,7 +560,7 @@ static struct tcp6_l2_flags_buf_t {
 #endif
 	struct tap_hdr taph;	/* 14					   2 */
 	struct ipv6hdr ip6h;	/* 32					  20 */
-	struct tcphdr th	/* 72 */ __attribute__ ((aligned(4))); /* 60 */ 
+	struct tcphdr th	/* 72 */ __attribute__ ((aligned(4))); /* 60 */
 	char opts[OPT_MSS_LEN + OPT_WS_LEN + 1];
 #ifdef __AVX2__
 } __attribute__ ((packed, aligned(32)))
@@ -3308,14 +3308,14 @@ void tcp_timer(struct ctx *c, const struct timespec *ts)
 		struct tcp_port_detect_arg detect_arg = { c, 0 };
 		struct tcp_port_rebind_arg rebind_arg = { c, 0 };
 
-		if (c->tcp.fwd_in.mode == FWD_AUTO) {
+		if (c->tcp.fwd_out.mode == FWD_AUTO) {
 			detect_arg.detect_in_ns = 0;
 			tcp_port_detect(&detect_arg);
 			rebind_arg.bind_in_ns = 1;
 			NS_CALL(tcp_port_rebind, &rebind_arg);
 		}
 
-		if (c->tcp.fwd_out.mode == FWD_AUTO) {
+		if (c->tcp.fwd_in.mode == FWD_AUTO) {
 			detect_arg.detect_in_ns = 1;
 			NS_CALL(tcp_port_detect, &detect_arg);
 			rebind_arg.bind_in_ns = 0;
-- 
2.39.2

    

Paul Holzinger

Stefano Brivio

Paul Holzinger

Stefano Brivio

Stefano Brivio

Stefano Brivio

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