From ab13c14a1480561bb9f59ccfbbd6045e0484ce9c Mon Sep 17 00:00:00 2001
From: Guus Sliepen <guus@tinc-vpn.org>
Date: Sun, 5 Jun 2016 14:47:21 +0200
Subject: [PATCH] Preserve IPv6 scope_id in edges.
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When creating an edge after authenticating a peer, we copy the
address used for the TCP connection, but change the port to that used
for UDP. But the way we did it discarded the scope_id for IPv6
addresses. This prevented UDP communication from working correctly when
connecting to a peer on the same LAN using an IPv6 link-local address.

Thanks to Rafał Leśniak for pointing out this issue.
---
 src/netutl.c        | 19 +++++++++++++++++++
 src/netutl.h        |  1 +
 src/protocol_auth.c | 13 +++----------
 3 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/src/netutl.c b/src/netutl.c
index 2eebb644..a9ad17ce 100644
--- a/src/netutl.c
+++ b/src/netutl.c
@@ -234,3 +234,22 @@ void sockaddrunmap(sockaddr_t *sa) {
 		sa->in.sin_family = AF_INET;
 	}
 }
+
+void sockaddr_setport(sockaddr_t *sa, const char *port) {
+	uint16_t portnum = htons(atoi(port));
+	if(!portnum)
+		return;
+	switch(sa->sa.sa_family) {
+		case AF_INET:
+			sa->in.sin_port = portnum;
+			break;
+		case AF_INET6:
+			sa->in6.sin6_port = portnum;
+			break;
+		case AF_UNKNOWN:
+			free(sa->unknown.port);
+			sa->unknown.port = xstrdup(port);
+		default:
+			return;
+	}
+}
diff --git a/src/netutl.h b/src/netutl.h
index 471cae7f..2e2f2936 100644
--- a/src/netutl.h
+++ b/src/netutl.h
@@ -34,5 +34,6 @@ extern int sockaddrcmp_noport(const sockaddr_t *, const sockaddr_t *);
 extern void sockaddrunmap(sockaddr_t *);
 extern void sockaddrfree(sockaddr_t *);
 extern void sockaddrcpy(sockaddr_t *, const sockaddr_t *);
+extern void sockaddr_setport(sockaddr_t *, const char *);
 
 #endif /* __TINC_NETUTL_H__ */
diff --git a/src/protocol_auth.c b/src/protocol_auth.c
index 0a7ad1ca..65c5e89e 100644
--- a/src/protocol_auth.c
+++ b/src/protocol_auth.c
@@ -790,7 +790,6 @@ bool ack_h(connection_t *c, const char *request) {
 		return upgrade_h(c, request);
 
 	char hisport[MAX_STRING_SIZE];
-	char *hisaddress;
 	int weight, mtu;
 	uint32_t options;
 	node_t *n;
@@ -867,19 +866,13 @@ bool ack_h(connection_t *c, const char *request) {
 	c->edge = new_edge();
 	c->edge->from = myself;
 	c->edge->to = n;
-	sockaddr2str(&c->address, &hisaddress, NULL);
-	c->edge->address = str2sockaddr(hisaddress, hisport);
-	free(hisaddress);
+	sockaddr_setport(&c->address, hisport);
 	sockaddr_t local_sa;
 	socklen_t local_salen = sizeof local_sa;
 	if (getsockname(c->socket, &local_sa.sa, &local_salen) < 0)
 		logger(DEBUG_ALWAYS, LOG_WARNING, "Could not get local socket address for connection with %s", c->name);
-	else {
-		char *local_address;
-		sockaddr2str(&local_sa, &local_address, NULL);
-		c->edge->local_address = str2sockaddr(local_address, myport);
-		free(local_address);
-	}
+	else
+		sockaddr_setport(&local_sa, myport);
 	c->edge->weight = (weight + c->estimated_weight) / 2;
 	c->edge->connection = c;
 	c->edge->options = c->options;
-- 
2.20.1