Fix: broken redudp

libc-compat.h

@@ -32,6 +32,11 @@
 #   define IP_TRANSPARENT 19
 #endif
 
+#ifndef IPV6_TRANSPARENT
+#   warning Using hardcoded value for IPV6_TRANSPARENT as libc headers do not define it.
+#   define IPV6_TRANSPARENT 75
+#endif
+
 #ifndef SOL_IP
 #   warning Using hardcoded value for SOL_IP as libc headers do not define it.
 #   define SOL_IP IPPROTO_IP

redudp.c

@@ -220,8 +220,7 @@ static void bound_udp4_action(const void *nodep, const VISIT which, const int de
 
 static int do_tproxy(redudp_instance* instance)
 {
-    // When listner is bound to IPv6 address, TPORXY must be used.
-    return instance->config.bindaddr.ss_family == AF_INET6 || instance->config.dest == NULL;
+    return instance->config.dest == NULL;
 }
 
 struct sockaddr_storage* get_destaddr(redudp_client *client)

utils.c

@@ -77,9 +77,9 @@ int red_recv_udp_pkt(
             if (
                 ((cmsg->cmsg_level == SOL_IP && cmsg->cmsg_type == IP_ORIGDSTADDR)
 #ifdef SOL_IPV6
-		 || (cmsg->cmsg_level == SOL_IPV6 && cmsg->cmsg_type == IPV6_ORIGDSTADDR)
+                 || (cmsg->cmsg_level == SOL_IPV6 && cmsg->cmsg_type == IPV6_ORIGDSTADDR)
 #endif
-		 ) &&
+                 ) &&
                 (cmsg->cmsg_len == CMSG_LEN(sizeof(struct sockaddr_in))
                  || cmsg->cmsg_len == CMSG_LEN(sizeof(struct sockaddr_in6))) &&
                 cmsg->cmsg_len <= CMSG_LEN(sizeof(*toaddr))
@@ -497,7 +497,14 @@ size_t get_write_hwm(struct bufferevent *bufev)
 int make_socket_transparent(int fd)
 {
     int on = 1;
-    int error = setsockopt(fd, SOL_IP, IP_TRANSPARENT, &on, sizeof(on));
+    int error = 0;
+#ifdef SOL_IPV6
+    // Try IPv6 first
+    error = setsockopt(fd, SOL_IPV6, IPV6_TRANSPARENT, &on, sizeof(on));
+    if (!error)
+        return error;
+#endif
+    error = setsockopt(fd, SOL_IP, IP_TRANSPARENT, &on, sizeof(on));
     if (error)
         log_errno(LOG_ERR, "setsockopt(..., SOL_IP, IP_TRANSPARENT)");
     return error;