Use pktinfo for explicit UDP wildcard listeners

In net-server.c, use pktinfo on UDP server sockets if they are bound
to wildcard addresses, whether that is explicit or implicit in the
address specification.

(cherry picked from commit d005beaa72c70bc28b2b0b49b9d83eff160ca8f1)

ticket: 8530
version_fixed: 1.15.1

diff --git a/src/lib/apputils/net-server.c b/src/lib/apputils/net-server.c
index d64ffddd682923a0cf898e3b405c2f02ccdb7150..29ec84a15b22250e80b4918bf5eafcbe93e860a2 100644 (file)
--- a/src/lib/apputils/net-server.c
+++ b/src/lib/apputils/net-server.c
@@ -105,6 +105,17 @@ paddr(struct sockaddr *sa)
     return buf;
 }
 
+/* Return true if sa is an IPv4 or IPv6 wildcard address. */
+static int
+is_wildcard(struct sockaddr *sa)
+{
+    if (sa->sa_family == AF_INET6)
+        return IN6_IS_ADDR_UNSPECIFIED(&sa2sin6(sa)->sin6_addr);
+    else if (sa->sa_family == AF_INET)
+        return sa2sin(sa)->sin_addr.s_addr == INADDR_ANY;
+    return 0;
+}
+
 /* KDC data.  */
 
 enum conn_type {
@@ -753,7 +764,7 @@ setup_socket(struct socksetup *data, struct bind_address *ba,
     }
 
     /* Try to turn on pktinfo for UDP wildcard sockets. */
-    if (ba->type == UDP && ba->address == NULL) {
+    if (ba->type == UDP && is_wildcard(sock_address)) {
         krb5_klog_syslog(LOG_DEBUG, _("Setting pktinfo on socket %s"),
                          paddr(sock_address));
         ret = set_pktinfo(sock, sock_address->sa_family);