[PATCH] Fix segfault on TCP connection before first passt socket connection

[Volker Diels-Grabsch <v@njh.eu>]

This issue can be reproduced by running passt with TCP forwarding
and connecting to that TCP port before the first client (e.g. QEMU)
connects to the passt socket.  Example:

   (sleep 0.1; ssh -p 22000 127.0.0.1) & passt -f -t 22000:22

Although this commit likely doesn't fix the root cause of this issue,
it does reliably fix the segfault.
---
 tcp_buf.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tcp_buf.c b/tcp_buf.c
index bc898de..1a06f15 100644
--- a/tcp_buf.c
+++ b/tcp_buf.c
@@ -120,6 +120,9 @@ static void tcp_revert_seq(const struct ctx *c, struct tcp_tap_conn **conns,
 		uint32_t seq = ntohl(th->seq);
 		uint32_t peek_offset;
 
+		if (conn == NULL)
+			continue;
+
 		if (SEQ_LE(conn->seq_to_tap, seq))
 			continue;
 
-- 
@@ -120,6 +120,9 @@ static void tcp_revert_seq(const struct ctx *c, struct tcp_tap_conn **conns,
 		uint32_t seq = ntohl(th->seq);
 		uint32_t peek_offset;
 
+		if (conn == NULL)
+			continue;
+
 		if (SEQ_LE(conn->seq_to_tap, seq))
 			continue;
 
-- 
2.47.3