TD v6 Client

td-client-v6.patch

diff --git a/client/l2tp_client.c b/client/l2tp_client.c
index 16fdf3c..6ea2aae 100644
--- a/client/l2tp_client.c
+++ b/client/l2tp_client.c
@@ -65,6 +65,7 @@
 
 // Overhead of IP and UDP headers for measuring PMTU.
 #define IPV4_HDR_OVERHEAD 28
+#define IPV6_HDR_OVERHEAD 48
 
 // L2TP data header overhead for calculating tunnel MTU; takes
 // the following headers into account:
@@ -176,7 +177,7 @@ typedef struct {
   // External hook script.
   char *hook;
   // Local IP endpoint.
-  struct sockaddr_in local_endpoint;
+  struct addrinfo *local_endpoint;
   // Broker hostname.
   char *broker_hostname;
   // Broker port (or service name).
@@ -360,7 +361,7 @@ void put_u32(char **buffer, uint32_t value)
   (*buffer) += sizeof(value);
 }
 
-l2tp_context *context_new(char *uuid, const char *local_ip, const char *broker_hostname,
+l2tp_context *context_new(char *uuid, const char *local_addr, const char *broker_hostname,
   char *broker_port, char *tunnel_iface, char *bind_iface, char *hook, int tunnel_id, int limit_bandwidth_down)
 {
   l2tp_context *ctx = (l2tp_context*) calloc(1, sizeof(l2tp_context));
@@ -371,11 +372,17 @@ l2tp_context *context_new(char *uuid, const char *local_ip, const char *broker_h
 
   ctx->state = STATE_REINIT;
 
-  ctx->local_endpoint.sin_family = AF_INET;
-  ctx->local_endpoint.sin_port = 0;
-  if (inet_aton(local_ip, &ctx->local_endpoint.sin_addr) < 0) {
-    syslog(LOG_ERR, "Failed to parse local endpoint!");
-    goto free_and_return;
+  struct addrinfo hints;
+  memset(&hints, 0, sizeof(hints));
+  hints.ai_family = AF_UNSPEC;
+  hints.ai_socktype = SOCK_DGRAM;
+  hints.ai_protocol = 0;
+  hints.ai_flags = AI_PASSIVE|AI_ADDRCONFIG;
+  struct addrinfo* res = 0;
+  int err = getaddrinfo(local_addr, 0, &hints, &ctx->local_endpoint);
+  if (err) {
+      syslog(LOG_ERR, "Failed to parse or resolve local endpoint! (err=%d/%s)", err, gai_strerror(err));
+      goto free_and_return;
   }
 
   ctx->broker_hostname = strdup(broker_hostname);
@@ -421,9 +428,11 @@ int context_reinitialize(l2tp_context *ctx)
   // because other functions than the state machine call this function.
   ctx->state = STATE_REINIT;
 
+  struct addrinfo *local_endpoint = ctx->local_endpoint;
+
   if (ctx->fd > 0)
     close(ctx->fd);
-  ctx->fd = socket(AF_INET, SOCK_DGRAM, 0);
+  ctx->fd = socket(local_endpoint->ai_family, local_endpoint->ai_socktype, local_endpoint->ai_protocol);
   if (ctx->fd < 0)
     return -1;
 
@@ -438,8 +447,9 @@ int context_reinitialize(l2tp_context *ctx)
     }
   }
 
-  if (bind(ctx->fd, (struct sockaddr*) &ctx->local_endpoint, sizeof(ctx->local_endpoint)) < 0) {
-    syslog(LOG_ERR, "Failed to bind to local endpoint - check WAN connectivity!");
+  int err = bind(ctx->fd, local_endpoint->ai_addr, local_endpoint->ai_addrlen);
+  if (err < 0) {
+    syslog(LOG_ERR, "Failed to bind to local endpoint - check WAN connectivity! (err=%s (%d))", strerror(err), err);
     return -1;
   }
 
@@ -491,10 +501,16 @@ void context_start_connect(l2tp_context *ctx)
   if (ctx->state != STATE_RESOLVING)
     return;
 
+  char *broker_host = ctx->broker_hostname;
+  // If this is an IPv6 address we need to cut off the brackets
+  if(broker_host[0] == '[') {
+    broker_host++[strlen(broker_host)] = 0;;
+  }
+
   memset(&ctx->broker_reshints, 0, sizeof(struct addrinfo));
-  ctx->broker_reshints.ai_family = AF_INET;
+  ctx->broker_reshints.ai_family = AF_UNSPEC;
   ctx->broker_reshints.ai_socktype = SOCK_DGRAM;
-  ctx->broker_resq = asyncns_getaddrinfo(asyncns_context, ctx->broker_hostname, ctx->broker_port,
+  ctx->broker_resq = asyncns_getaddrinfo(asyncns_context, broker_host, ctx->broker_port,
     &ctx->broker_reshints);
   ctx->timer_resolving = timer_now();
 
@@ -543,9 +559,9 @@ void context_setup_limits(l2tp_context *ctx)
 void context_process_control_packet(l2tp_context *ctx)
 {
   char buffer[2048];
-  struct sockaddr_in endpoint;
+  struct sockaddr_in6 endpoint;
   socklen_t endpoint_len = sizeof(endpoint);
-  ssize_t bytes = recvfrom(ctx->fd, &buffer, sizeof(buffer), 0, (struct sockaddr*) &endpoint,
+  ssize_t bytes = recvfrom(ctx->fd, &buffer, sizeof(buffer), 0, (struct sockaddr_in6*) &endpoint,
     &endpoint_len);
 
   // A valid package must at least 6 byte long.
@@ -661,7 +677,9 @@ void context_process_control_packet(l2tp_context *ctx)
         if (payload_length != 2)
           break;
         // Process a PMTU probe.
-        uint16_t psize = parse_u16(&buf) + IPV4_HDR_OVERHEAD;
+        struct addrinfo *local_endpoint = ctx->local_endpoint;
+        int overhead = local_endpoint->ai_family == AF_INET6 ? IPV4_HDR_OVERHEAD : IPV6_HDR_OVERHEAD;
+        uint16_t psize = parse_u16(&buf) + overhead;
         if (psize > ctx->probed_pmtu)
           ctx->probed_pmtu = psize;
       }
@@ -815,7 +833,9 @@ void context_send_pmtu_probe(l2tp_context *ctx, size_t size)
   put_u8(&buf, 0);
 
   // Send the packet.
-  if (send(ctx->fd, &buffer, size - IPV4_HDR_OVERHEAD, 0) < 0) {
+  struct addrinfo *local_endpoint = ctx->local_endpoint;
+  int overhead = local_endpoint->ai_family == AF_INET6 ? IPV4_HDR_OVERHEAD : IPV6_HDR_OVERHEAD;
+  if (send(ctx->fd, &buffer, size - overhead, 0) < 0) {
     switch (errno) {
       // Sometimes EAFNOSUPPORT is emitted for messages larger than the local MTU in case of PPPoE.
       case EAFNOSUPPORT:
@@ -1264,6 +1284,7 @@ void context_free(l2tp_context *ctx)
   free(ctx->broker_hostname);
   free(ctx->broker_port);
   free(ctx->bind_iface);
+  freeaddrinfo(ctx->local_endpoint);
   free(ctx);
 }
 
@@ -1317,7 +1338,7 @@ int main(int argc, char **argv)
 
   // Parse program options.
   int log_option = 0;
-  char *uuid = NULL, *local_ip = "0.0.0.0", *tunnel_iface = NULL, *bind_iface_opt = NULL;
+  char *uuid = NULL, *local_ip = "::", *tunnel_iface = NULL, *bind_iface_opt = NULL;
   char *hook = NULL;
   unsigned int tunnel_id = 1;
   int limit_bandwidth_down = 0;
@@ -1346,7 +1367,7 @@ int main(int argc, char **argv)
           return 1;
         }
 
-        char *pos = strchr(optarg, ':');
+        char *pos = strrchr(optarg, ':');
         if (!pos) {
           fprintf(stderr, "ERROR: Each broker must be passed in the format 'host:port'!\n");
           return 1;