From 48e353e9fdf189c4fd5fa7ebc76a72535b4f6632 Mon Sep 17 00:00:00 2001
From: Guus Sliepen <guus@tinc-vpn.org>
Date: Sun, 5 Jun 2016 15:23:07 +0200
Subject: [PATCH 1/1] 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 |  6 ++----
 3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/src/netutl.c b/src/netutl.c
index 2abbe86..37887be 100644
--- a/src/netutl.c
+++ b/src/netutl.c
@@ -231,6 +231,25 @@ void sockaddrunmap(sockaddr_t *sa) {
 	}
 }
 
+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;
+	}
+}
+
 /* Subnet mask handling */
 
 int maskcmp(const void *va, const void *vb, int masklen) {
diff --git a/src/netutl.h b/src/netutl.h
index 7fc41e8..7c31f2b 100644
--- a/src/netutl.h
+++ b/src/netutl.h
@@ -34,6 +34,7 @@ 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 *);
 extern int maskcmp(const void *, const void *, int);
 extern void maskcpy(void *, const void *, int, int);
 extern void mask(void *, int, int);
diff --git a/src/protocol_auth.c b/src/protocol_auth.c
index 8fa9b93..091629a 100644
--- a/src/protocol_auth.c
+++ b/src/protocol_auth.c
@@ -516,7 +516,6 @@ static void send_everything(connection_t *c) {
 
 bool ack_h(connection_t *c) {
 	char hisport[MAX_STRING_SIZE];
-	char *hisaddress;
 	int weight, mtu;
 	uint32_t options;
 	node_t *n;
@@ -585,9 +584,8 @@ bool ack_h(connection_t *c) {
 	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);
+	sockaddrcpy(&c->edge->address, &c->address);
+	sockaddr_setport(&c->edge->address, hisport);
 	c->edge->weight = (weight + c->estimated_weight) / 2;
 	c->edge->connection = c;
 	c->edge->options = c->options;
-- 
2.25.1