platform: add and use nm_sock_addr_union_to_string()

We still don't use getnameinfo(). This is used for logging,
where we want to see a string representation that is as close
as possible to the actual bytes (to spot differences). It should
not be obfuscated by a libc function out of our control.

Also fix the notation for the IPv6 scope ID to use the common '%'
character.

src/platform/nm-platform.c

@@ -1997,7 +1997,7 @@ int
 nm_platform_link_wireguard_change (NMPlatform *self,
                                    int ifindex,
                                    const NMPlatformLnkWireGuard *lnk_wireguard,
-                                   const struct _NMPWireGuardPeer *peers,
+                                   const NMPWireGuardPeer *peers,
                                    guint peers_len)
 {
 	_CHECK_SELF (self, klass, -NME_BUG);
@@ -5604,33 +5604,24 @@ nm_platform_wireguard_peer_to_string (const NMPWireGuardPeer *peer, char *buf, g
 {
 	char *buf0 = buf;
 	gs_free char *public_key_b64 = NULL;
-	char s_endpoint[NM_UTILS_INET_ADDRSTRLEN + 100];
+	char s_sockaddr[NM_UTILS_INET_ADDRSTRLEN + 100];
+	char s_endpoint[20 + sizeof (s_sockaddr)];
 	char s_addr[NM_UTILS_INET_ADDRSTRLEN];
-	char s_scope_id[40];
 	guint i;
 
 	nm_utils_to_string_buffer_init (&buf, &len);
 
-	if (peer->endpoint.sa.sa_family == AF_INET) {
+	public_key_b64 = g_base64_encode (peer->public_key, sizeof (peer->public_key));
+
+	if (peer->endpoint.sa.sa_family != AF_UNSPEC) {
 		nm_sprintf_buf (s_endpoint,
-		                " endpoint %s:%u",
-		                nm_utils_inet4_ntop (peer->endpoint.in.sin_addr.s_addr, s_addr),
-		                (guint) htons (peer->endpoint.in.sin_port));
-	} else if (peer->endpoint.sa.sa_family == AF_INET6) {
-		if (peer->endpoint.in6.sin6_scope_id != 0)
-			nm_sprintf_buf (s_scope_id, "@%u", peer->endpoint.in6.sin6_scope_id);
-		else
-			s_scope_id[0] = '\0';
-		nm_sprintf_buf (s_endpoint,
-		                " endpoint [%s]%s:%u",
-		                nm_utils_inet6_ntop (&peer->endpoint.in6.sin6_addr, s_addr),
-		                s_scope_id,
-		                (guint) htons (peer->endpoint.in6.sin6_port));
+		                " endpoint %s",
+		                nm_sock_addr_union_to_string (&peer->endpoint,
+		                                              s_sockaddr,
+		                                              sizeof (s_sockaddr)));
 	} else
 		s_endpoint[0] = '\0';
 
-	public_key_b64 = g_base64_encode (peer->public_key, sizeof (peer->public_key));
-
 	nm_utils_strbuf_append (&buf, &len,
 	                        "public-key %s"
 	                        "%s" /* preshared-key */

src/platform/nmp-object.c

@@ -228,6 +228,51 @@ nm_sock_addr_union_cpy_untrusted (NMSockAddrUnion *dst,
 	nm_assert (dst->sa.sa_family == sa.sa_family);
 }
 
+const char *
+nm_sock_addr_union_to_string (const NMSockAddrUnion *sa,
+                              char *buf,
+                              gsize len)
+{
+	char s_addr[NM_UTILS_INET_ADDRSTRLEN];
+	char s_scope_id[40];
+
+	if (!nm_utils_to_string_buffer_init_null (sa, &buf, &len))
+		return buf;
+
+	/* maybe we should use getnameinfo(), but here implement it ourself.
+	 *
+	 * We want to see the actual bytes for debugging (as we understand them),
+	 * and now what getnameinfo() makes of it. Also, it's simpler this way. */
+
+	switch (sa->sa.sa_family) {
+	case AF_INET:
+		g_snprintf (buf, len,
+		            "%s:%u",
+		            nm_utils_inet4_ntop (sa->in.sin_addr.s_addr, s_addr),
+		            (guint) htons (sa->in.sin_port));
+		break;
+	case AF_INET6:
+		g_snprintf (buf, len,
+		            "[%s%s]:%u",
+		            nm_utils_inet6_ntop (&sa->in6.sin6_addr, s_addr),
+		            (  sa->in6.sin6_scope_id != 0
+		             ? nm_sprintf_buf (s_scope_id, "%u", sa->in6.sin6_scope_id)
+		             : ""),
+		            (guint) htons (sa->in6.sin6_port));
+		break;
+	case AF_UNSPEC:
+		g_snprintf (buf, len, "unspec");
+		break;
+	default:
+		g_snprintf (buf, len,
+		            "{addr-family:%u}",
+		            (unsigned) sa->sa.sa_family);
+		break;
+	}
+
+	return buf;
+}
+
 /*****************************************************************************/
 
 static const NMDedupMultiIdxTypeClass _dedup_multi_idx_type_class;

src/platform/nmp-object.h

@@ -57,6 +57,10 @@ void nm_sock_addr_union_cpy_untrusted (NMSockAddrUnion *dst,
                                        gconstpointer src /* unaligned (const NMSockAddrUnion *) */,
                                        gsize src_len);
 
+const char *nm_sock_addr_union_to_string (const NMSockAddrUnion *sa,
+                                          char *buf,
+                                          gsize len);
+
 /*****************************************************************************/
 
 typedef struct {