cleaning

1 files changed, 128 insertions, 108 deletions

diff --git a/src/transport/gnunet-nat-server-windows.c b/src/transport/gnunet-nat-server-windows.c
index bb135ed08..11c63aa9d 100644
--- a/src/transport/gnunet-nat-server-windows.c
+++ b/src/transport/gnunet-nat-server-windows.c
@@ -72,7 +72,7 @@
 
 #define ICMP_ECHO 8
 
-#define ICMP_TIME_EXCEEDED      11      /* Time Exceeded */
+#define ICMP_TIME_EXCEEDED 11
 
 /**
  * How often do we send our ICMP messages to receive replies?
@@ -82,7 +82,7 @@
 /**
  * IPv4 header.
  */
-struct ip_packet 
+struct ip_header 
 {
 
   /**
@@ -139,7 +139,20 @@ struct ip_packet
 /**
  * Format of ICMP packet.
  */
-struct icmp_packet 
+struct icmp_ttl_exceeded_header 
+{
+  uint8_t type;
+
+  uint8_t code;
+
+  uint16_t checksum;
+
+  uint32_t unused;
+
+  /* followed by original payload */
+};
+
+struct icmp_echo_header
 {
   uint8_t type;
 
@@ -153,13 +166,15 @@ struct icmp_packet
 /**
  * Beginning of UDP packet.
  */
-struct udp_packet
+struct udp_header
 {
   uint16_t src_port;
 
   uint16_t dst_port;
 
-  uint32_t length;
+  uint16_t length;
+
+  uint16_t crc;
 };
 
 /**
@@ -240,19 +255,17 @@ inet_pton (int af,
 static void
 send_icmp_echo (const struct in_addr *my_ip)
 {
-  struct icmp_packet icmp_echo;
+  char packet[sizeof (struct ip_header) + sizeof (struct icmp_echo_header)];
+  struct icmp_ttl_exceeded_header icmp_echo;
+  struct ip_header ip_pkt;
   struct sockaddr_in dst;
   size_t off;
   int err;
-  struct ip_packet ip_pkt;
-  struct icmp_packet icmp_pkt;
-  char packet[sizeof (ip_pkt) + sizeof (icmp_pkt)];
 
   off = 0;
-  memset(&ip_pkt, 0, sizeof(ip_pkt));
   ip_pkt.vers_ihl = 0x45;
   ip_pkt.tos = 0;
-  ip_pkt.pkt_len = sizeof (packet);
+  ip_pkt.pkt_len = htons (sizeof (packet));
   ip_pkt.id = htons (256);
   ip_pkt.flags_frag_offset = 0;
   ip_pkt.ttl = IPDEFTTL;
@@ -260,18 +273,23 @@ send_icmp_echo (const struct in_addr *my_ip)
   ip_pkt.checksum = 0;
   ip_pkt.src_ip = my_ip->s_addr;
   ip_pkt.dst_ip = dummy.s_addr;
-  ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt, sizeof (ip_pkt)));
-  memcpy (&packet[off], &ip_pkt, sizeof (ip_pkt));
-  off += sizeof (ip_pkt);
+  ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
+                                        sizeof (struct ip_header)));
+  memcpy (&packet[off], 
+          &ip_pkt, 
+          sizeof (struct ip_header));
+  off += sizeof (struct ip_header);
 
   icmp_echo.type = ICMP_ECHO;
   icmp_echo.code = 0;
   icmp_echo.reserved = 0;
   icmp_echo.checksum = 0;
   icmp_echo.checksum = htons(calc_checksum((uint16_t*) &icmp_echo, 
-                                           sizeof (struct icmp_packet)));
-  memcpy (&packet[off], &icmp_echo, sizeof (icmp_echo));
-  off += sizeof (icmp_echo);
+                                           sizeof (struct icmp_echo_header)));
+  memcpy (&packet[off], 
+          &icmp_echo, 
+          sizeof (struct icmp_echo_header));
+  off += sizeof (struct icmp_echo_header);
  
   memset (&dst, 0, sizeof (dst));
   dst.sin_family = AF_INET;
@@ -297,11 +315,9 @@ send_icmp_echo (const struct in_addr *my_ip)
 
 /**
  * Send a UDP message to the dummy IP.
- *
- * @param my_ip source address (our ip address)
  */
 static void
-send_udp (const struct in_addr *my_ip)
+send_udp ()
 {
   struct sockaddr_in dst;
   ssize_t err;
@@ -321,7 +337,7 @@ send_udp (const struct in_addr *my_ip)
               "sendto failed: %s\n", strerror(errno));
 #endif
     }
-  else if (err != 0) 
+  else if (0 != err) 
     {
       fprintf(stderr,
               "Error: partial send of ICMP message\n");
@@ -337,13 +353,14 @@ process_icmp_response ()
 {
   char buf[65536];
   ssize_t have;
-  struct in_addr sip;
-  struct ip_packet ip_pkt;
-  struct icmp_packet icmp_pkt;
-  struct udp_packet udp_pkt;
+  struct in_addr source_ip;
+  struct ip_header ip_pkt;
+  struct icmp_ttl_exceeded_header icmp_pkt;
+  struct icmp_echo_header icmp_echo;
+  struct udp_header udp_pkt;
   size_t off;
-  int have_port;
-  uint32_t port;
+  uint16_t port;
+  DWORD ssize;
 
   have = read (icmpsock, buf, sizeof (buf));
   if (have == -1)
@@ -359,82 +376,85 @@ process_icmp_response ()
            "Received message of %u bytes\n",
            (unsigned int) have);
 #endif
-  if (have == sizeof (struct ip_packet) *2 + sizeof (struct icmp_packet) * 2 + sizeof(uint32_t))
+  if (have < (ssize_t) (sizeof (struct ip_header) + sizeof (struct icmp_ttl_exceeded_header) + sizeof (struct ip_header)))
     {
-      have_port = 1;
-    }
-  else if (have != sizeof (struct ip_packet) *2 + sizeof (struct icmp_packet) * 2)
-    {
-#if VERBOSE
-      fprintf (stderr,
-               "Received ICMP message of unexpected size: %u bytes\n",
-               (unsigned int) have);
-#endif
+      /* malformed */
       return;
     }
   off = 0;
-  memcpy (&ip_pkt, &buf[off], sizeof (ip_pkt));
-  off += sizeof (ip_pkt);
-  memcpy (&icmp_pkt, &buf[off], sizeof (icmp_pkt));
-  off += sizeof (icmp_pkt);
-  if ( ((ip_pkt.proto != IPPROTO_ICMP) && (ip_pkt.proto != IPPROTO_UDP)) ||
-       (icmp_pkt.type != ICMP_TIME_EXCEEDED) || 
-       (icmp_pkt.code != 0) )
-    {
-      /* maybe we got an actual reply back... */
-      return;    
-    }
-  memcpy(&sip, 
+  memcpy (&ip_pkt,
+          &buf[off], 
+          sizeof (struct ip_header));
+  off += sizeof (struct ip_header);
+  memcpy(&source_ip, 
          &ip_pkt.src_ip, 
-         sizeof (sip));
-  memcpy (&ip_pkt, &buf[off], sizeof (ip_pkt));
-  off += sizeof (ip_pkt);
-
-  if (have_port)
+         sizeof (source_ip));
+  memcpy (&icmp_ttl, 
+          &buf[off], 
+          sizeof (struct icmp_ttl_exceeded_header));
+  off += sizeof (struct icmp_ttl_exceeded_header);
+  if ( (ICMP_TIME_EXCEEDED != icmp_ttl.type) || 
+       (0 != icmp_ttl.code) )
     {
-      memcpy(&port, 
-             &buf[sizeof (struct ip_packet) *2 + sizeof (struct icmp_packet) * 2], 
-             sizeof(uint32_t));
-      port = ntohs(port);
-      DWORD ssize = sizeof(buf);
-      WSAAddressToString((LPSOCKADDR)&sip, 
-                         sizeof(sip),
-                         NULL, 
-                         buf, 
-                         &ssize);
-      fprintf (stdout, 
-               "%s:%d\n",
-               buf, 
-               port);
+      /* different type than what we want */
+      return;
     }
-  else if (ip_pkt.proto == IPPROTO_UDP)
+  /* skip 2nd IP header */
+  memcpy (&ip_pkt,
+          &buf[off], 
+          sizeof (struct ip_header));
+  off += sizeof (struct ip_header);
+
+  switch (ip_pkt.proto)
     {
-      memcpy(&udp_pkt,
-             &buf[off],
-             sizeof(udp_pkt));
-      DWORD ssize = sizeof(buf);
-      WSAAddressToString((LPSOCKADDR)&sip, 
-                         sizeof(sip),
-                         NULL,
-                         buf, 
-                         &ssize);
-      fprintf (stdout, 
-               "%s:%d\n", 
-               buf, 
-               ntohs((uint16_t)udp_pkt.length));
+    case IPPROTO_ICMP:
+      if (have != (sizeof (struct ip_header) * 2 + 
+                   sizeof (struct icmp_ttl_exceeded_header) + 
+                   sizeof (struct icmp_echo_header)) )
+        {
+          /* malformed */
+          return;
+        }
+      /* grab ICMP ECHO content */
+      memcpy (&icmp_echo,
+              &buf[off],
+              sizeof (struct icmp_echo_header));
+      port = (uint16_t)  ntohl (icmp_echo.reserved);
+      break;
+    case IPPROTO_UDP:
+      if (have != (sizeof (struct ip_header) * 2 + 
+                   sizeof (struct icmp_ttl_exceeded_header) + 
+                   sizeof (struct udp_header)) )
+        {
+          /* malformed */
+          return;
+        }
+      /* grab UDP content */
+      memcpy (&udp_pkt,
+              &buf[off],
+              sizeof (struct udp_header));
+      port = ntohs (udp_pkt.length);
+      break;
+    default:   
+      /* different type than what we want */
+      return;
     }
+  
+  ssize = sizeof(buf);
+  WSAAddressToString((LPSOCKADDR)&source_ip, 
+                     sizeof(source_ip),
+                     NULL,
+                     buf, 
+                     &ssize);
+  if (port == 0)
+    fprintf (stdout,
+             "%s\n",
+             buf);
   else
-    {
-      DWORD ssize = sizeof(buf);
-      WSAAddressToString((LPSOCKADDR)&sip,
-                         sizeof(sip),
-                         NULL,
-                         buf,
-                         &ssize);
-      fprintf (stdout, 
-               "%s\n",
-               buf);
-    }
+    fprintf (stdout,
+             "%s:%u\n",
+             buf,
+             (unsigned int) port);
   fflush (stdout);
 }
 
@@ -481,10 +501,10 @@ make_raw_socket ()
       return INVALID_SOCKET;
     }
 
-  if (setsockopt(rawsock, 
-                 SOL_SOCKET, 
-                 SO_BROADCAST, 
-                 (char*)&bOptVal, bOptLen) != 0)
+  if (0 != setsockopt(rawsock, 
+                      SOL_SOCKET, 
+                      SO_BROADCAST, 
+                      (char*)&bOptVal, bOptLen))
     {
       fprintf(stderr, 
               "Error setting SO_BROADCAST to ON: %s\n",
@@ -492,10 +512,10 @@ make_raw_socket ()
       closesocket(rawsock);
       return INVALID_SOCKET;
     }
-  if (setsockopt(rawsock, 
-                 IPPROTO_IP, 
-                 IP_HDRINCL, 
-                 (char*)&bOptVal, bOptLen) != 0)
+  if (0 != setsockopt(rawsock, 
+                      IPPROTO_IP, 
+                      IP_HDRINCL, 
+                      (char*)&bOptVal, bOptLen))
     {
       fprintf(stderr, 
               "Error setting IP_HDRINCL to ON: %s\n",
@@ -510,10 +530,11 @@ make_raw_socket ()
 /**
  * Create a UDP socket for writinging.
  *
- * @return -1 on error
+ * @param my_ip source address (our ip address)
+ * @return INVALID_SOCKET on error
  */
 static SOCKET
-make_udp_socket ()
+make_udp_socket (const struct in_addr *my_ip)
 {
   SOCKET ret;
   struct sockaddr_in addr;
@@ -528,9 +549,8 @@ make_udp_socket ()
     }
   memset (&addr, 0, sizeof (addr));
   addr.sin_family = AF_INET;
-  /* addr.sin_addr zero == ours (hopefully...) */
+  addr.sin_addr = *my_ip;
   addr.sin_port = htons (NAT_TRAV_PORT);
-
   if (0 != bind (ret,
                  &addr,
                  sizeof(addr)))
@@ -555,7 +575,7 @@ main (int argc,
   WSADATA wsaData;
   unsigned int alt;
 
-  if (argc != 2)
+  if (2 != argc)
     {
       fprintf (stderr,
                "This program must be started with our (internal NAT) IP as the only argument.\n");
@@ -588,7 +608,7 @@ main (int argc,
       closesocket (icmpsock);
       return 3; 
     }
-  if (INVALID_SOCKET == (udpsock = make_udp_socket()))
+  if (INVALID_SOCKET == (udpsock = make_udp_socket(&external)))
     {
       closesocket (icmpsock);
       closesocket (rawsock);
@@ -614,7 +634,7 @@ main (int argc,
       if (0 == (++alt % 2))
         send_icmp_echo (&external);
       else
-        send_udp (&external);
+        send_udp ();
     }
   /* select failed (internal error or OS out of resources) */
   closesocket(icmpsock);