5 files changed, 62 insertions, 27 deletions

diff --git a/src/dns/gnunet-service-dns.c b/src/dns/gnunet-service-dns.c
index 5dc6641e7..288304600 100644
--- a/src/dns/gnunet-service-dns.c
+++ b/src/dns/gnunet-service-dns.c
@@ -419,18 +419,11 @@ request_done (struct RequestRecord *rr)
 
         spt = dst->sin6_port;
         dpt = src->sin6_port;
-        ip.traffic_class_h = 0;
-        ip.version  = 6; /* is there a named constant? I couldn't find one */
-        ip.traffic_class_l = 0;
-        ip.flow_label = 0;
-        ip.payload_length = htons ((uint16_t) reply_len);
-        ip.next_header = IPPROTO_UDP;
-        ip.hop_limit = 255; /* or lower? */
-        ip.source_address = dst->sin6_addr;
-        ip.destination_address = src->sin6_addr;
-        udp_crc_sum = GNUNET_CRYPTO_crc16_step (udp_crc_sum,
-                                                &ip.source_address, 
-                                                sizeof (struct in6_addr) * 2);
+        GNUNET_TUN_initialize_ipv6_header (&ip,
+                                           IPPROTO_UDP,
+                                           reply_len - sizeof (struct GNUNET_TUN_IPv6Header),
+                                           &dst->sin6_addr,
+                                           &src->sin6_addr);
         {
           uint32_t tmp;
           
diff --git a/src/exit/gnunet-daemon-exit.c b/src/exit/gnunet-daemon-exit.c
index a4a0f967d..664a86f23 100644
--- a/src/exit/gnunet-daemon-exit.c
+++ b/src/exit/gnunet-daemon-exit.c
@@ -1159,12 +1159,11 @@ prepare_ipv6_packet (const void *payload, size_t payload_length,
     return;
   }
 
-  pkt6->version = 6;
-  pkt6->next_header = protocol;
-  pkt6->payload_length = htons ((uint16_t) (len + sizeof (struct GNUNET_TUN_IPv6Header)));
-  pkt6->hop_limit = 255;
-  pkt6->destination_address = dst_address->address.ipv6;
-  pkt6->source_address = src_address->address.ipv6;
+  GNUNET_TUN_initialize_ipv6_header (pkt6,
+                                     protocol,
+                                     len,
+                                     &dst_address->address.ipv6,
+                                     &src_address->address.ipv6);
 
   switch (protocol)
   {
diff --git a/src/include/gnunet_tun_lib.h b/src/include/gnunet_tun_lib.h
index ae16bc65f..89cfdd2b3 100644
--- a/src/include/gnunet_tun_lib.h
+++ b/src/include/gnunet_tun_lib.h
@@ -165,4 +165,21 @@ GNUNET_TUN_initialize_ipv4_header (struct GNUNET_TUN_IPv4Header *ip,
                                    const struct in_addr *dst);
 
 
+/**
+ * Initialize an IPv6 header.
+ *
+ * @param ip header to initialize
+ * @param protocol protocol to use (i.e. IPPROTO_UDP)
+ * @param payload_length number of bytes of payload that follow (excluding IPv4 header)
+ * @param src source IP address to use
+ * @param dst destination IP address to use
+ */
+void
+GNUNET_TUN_initialize_ipv6_header (struct GNUNET_TUN_IPv6Header *ip,
+                                   uint8_t protocol,
+                                   uint16_t payload_length,
+                                   const struct in6_addr *src,
+                                   const struct in6_addr *dst);
+
+
 #endif
diff --git a/src/tun/tun.c b/src/tun/tun.c
index 97b7a730e..005c7013d 100644
--- a/src/tun/tun.c
+++ b/src/tun/tun.c
@@ -48,6 +48,7 @@ GNUNET_TUN_initialize_ipv4_header (struct GNUNET_TUN_IPv4Header *ip,
                                    const struct in_addr *src,
                                    const struct in_addr *dst)
 {
+  GNUNET_assert (payload_length <= UINT16_MAX - sizeof (struct GNUNET_TUN_IPv4Header));
   ip->header_length =  sizeof (struct GNUNET_TUN_IPv4Header) / 4;
   ip->version = 4;
   ip->diff_serv = 0;
@@ -65,5 +66,34 @@ GNUNET_TUN_initialize_ipv4_header (struct GNUNET_TUN_IPv4Header *ip,
 }
 
 
+/**
+ * Initialize an IPv6 header.
+ *
+ * @param ip header to initialize
+ * @param protocol protocol to use (i.e. IPPROTO_UDP), technically "next_header" for IPv6
+ * @param payload_length number of bytes of payload that follow (excluding IPv4 header)
+ * @param src source IP address to use
+ * @param dst destination IP address to use
+ */
+void
+GNUNET_TUN_initialize_ipv6_header (struct GNUNET_TUN_IPv6Header *ip,
+                                   uint8_t protocol,
+                                   uint16_t payload_length,
+                                   const struct in6_addr *src,
+                                   const struct in6_addr *dst)
+{
+  GNUNET_assert (payload_length <= UINT16_MAX - sizeof (struct GNUNET_TUN_IPv6Header));
+  ip->traffic_class_h = 0;
+  ip->version = 6;
+  ip->traffic_class_l = 0;
+  ip->flow_label = 0;
+  ip->next_header = protocol;
+  ip->payload_length = htons ((uint16_t) (payload_length + sizeof (struct GNUNET_TUN_IPv6Header)));
+  ip->hop_limit = FRESH_TTL;
+  ip->destination_address = *dst;
+  ip->source_address = *src;  
+}
+
+
 
 /* end of tun.c */
diff --git a/src/vpn/gnunet-service-vpn.c b/src/vpn/gnunet-service-vpn.c
index f0cdf6a3c..b352e216b 100644
--- a/src/vpn/gnunet-service-vpn.c
+++ b/src/vpn/gnunet-service-vpn.c
@@ -1636,15 +1636,11 @@ receive_tcp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
         msg->size = htons (size);
         tun->flags = htons (0);
         tun->proto = htons (ETH_P_IPV6);
-        ipv6->traffic_class_h = 0;
-        ipv6->version = 6;
-        ipv6->traffic_class_l = 0;
-        ipv6->flow_label = 0;
-        ipv6->payload_length = htons (sizeof (struct GNUNET_TUN_TcpHeader) + sizeof (struct GNUNET_TUN_IPv6Header) + mlen);
-        ipv6->next_header = IPPROTO_TCP;
-        ipv6->hop_limit = 255;
-        ipv6->source_address = ts->destination_ip.v6;
-        ipv6->destination_address = ts->source_ip.v6;
+        GNUNET_TUN_initialize_ipv6_header (ipv6,
+                                           IPPROTO_TCP,
+                                           sizeof (struct GNUNET_TUN_TcpHeader) + mlen,
+                                           &ts->destination_ip.v6,
+                                           &ts->source_ip.v6);
         tcp->spt = htons (ts->destination_port);
         tcp->dpt = htons (ts->source_port);
         tcp->crc = 0;