fix endianness of in_addr

Makefile

@@ -3,6 +3,7 @@ CFLAGS  = -g -Wall
 
 all:  nat_traversal
 
+# clang warn about unused argument, it requires -pthread when compiling but not when linking
 nat_traversal:  main.o nat_traversal.o nat_type.o 
 	$(CC) $(CFLAGS) -o nat_traversal main.o nat_traversal.o nat_type.o -pthread
 

main.c

@@ -12,13 +12,16 @@
 #define DEFAULT_SERVER_PORT 9988
 #define MSG_BUF_SIZE 512
 
-// use some public stun servers to detect port allocation rule
+// use public stun servers to detect port allocation rule
 static char *stun_servers[] = {
     "stun.ideasip.com",
     "stun.ekiga.net",
     "203.183.172.196"
 };
 
+// definition checked against extern declaration
+int verbose = 0;
+
 int main(int argc, char** argv)
 {
     char* stun_server = stun_servers[0];
@@ -28,7 +31,7 @@ int main(int argc, char** argv)
     char* punch_server = NULL;
     uint32_t peer_id = 0;
 
-    static char usage[] = "usage: [-h] [-H STUN_HOST] [-P STUN_PORT] [-s punch server] [-d id] [-i SOURCE_IP] [-p SOURCE_PORT]\n";
+    static char usage[] = "usage: [-h] [-H STUN_HOST] [-P STUN_PORT] [-s punch server] [-d id] [-i SOURCE_IP] [-p SOURCE_PORT] [-v verbose]\n";
     int opt;
     while ((opt = getopt (argc, argv, "H:h:P:p:s:d:i")) != -1)
     {
@@ -55,6 +58,8 @@ int main(int argc, char** argv)
             case 'i':
                 local_host = optarg;
                 break;
+            case 'v':
+                verbose = 1;
             case '?':
             default:
                 printf("invalid option: %c\n", opt);
@@ -67,9 +72,9 @@ int main(int argc, char** argv)
     char ext_ip[16] = {0};
     uint16_t ext_port = 0;
 
+    // TODO we should try another STUN server if failed
     nat_type type = detect_nat_type(stun_server, stun_port, local_host, local_port, ext_ip, &ext_port);
 
-    // TODO log
     printf("NAT type: %s\n", get_nat_desc(type));
     if (ext_port) {
         printf("external address: %s:%d\n", ext_ip, ext_port);
@@ -89,10 +94,6 @@ int main(int argc, char** argv)
     server_addr.sin_port = htons(DEFAULT_SERVER_PORT);
 
     client c;
-
-    // test
-    c.type = SymmetricNAT;
-
     if (init(self, server_addr, &c)) {
         printf("init failed\n");
 
@@ -100,8 +101,9 @@ int main(int argc, char** argv)
     }
 
     if (peer_id) {
+        printf("connecting to peer %d", peer_id);
         if (connect_to_peer(&c, peer_id) < 0) {
-            printf("failed to connect\n");
+            printf("failed to connect to peer %d\n", peer_id);
 
             return -1;
         }

nat_type.c

@@ -11,6 +11,8 @@
 
 #include "nat_type.h"
 
+#define MAX_RETRIES_NUM 3
+
 static const char* nat_types[] = {
 	"blocked",
 	"open internet",
@@ -125,7 +127,10 @@ static int send_bind_request(int sock, const char* remote_host, uint16_t remote_
 	memcpy(&remote_addr.sin_addr.s_addr, server->h_addr_list[0], server->h_length);
 	remote_addr.sin_port = htons(remote_port); 
 
+    int retries;
+    for (retries = 0; retries < MAX_RETRIES_NUM; retries++) {
         if (-1 == sendto(sock, buf, ptr - buf, 0, (struct sockaddr *)&remote_addr, sizeof(remote_addr))) {
+            // udp sendto barely failed
             free(buf);
 
             return -1;
@@ -134,15 +139,25 @@ static int send_bind_request(int sock, const char* remote_host, uint16_t remote_
         socklen_t fromlen = sizeof remote_addr;
 
         struct timeval tv;
-	tv.tv_sec = 5;
+        tv.tv_sec = 3;
         tv.tv_usec = 0;
         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv, sizeof(tv));
 
         if (recvfrom(sock, buf, 512, 0, (struct sockaddr *)&remote_addr, &fromlen) <= 0) {
+            if (errno != EAGAIN || errno != EWOULDBLOCK) {
                 free(buf);
 
                 return -1;
             }
+            //timout, retry
+        } else {
+            // got response
+            break;
+        }
+    }
+
+    if (retries == MAX_RETRIES_NUM)
+        return -1;
 
 	StunHeader reply_header;
 	memcpy(&reply_header, buf, sizeof(StunHeader));
@@ -278,7 +293,7 @@ nat_type detect_nat_type(const char* stun_host, uint16_t stun_port, const char*
 	} else { 
 		if (changed_ip != 0 && changed_port != 0) {
 			if (send_bind_request(s, stun_host, stun_port, ChangeIpFlag, ChangePortFlag, bind_result)) {
-				struct in_addr addr = {changed_ip};
+				struct in_addr addr = {htonl(changed_ip)};
 				char* alt_host = inet_ntoa(addr);
 
 				memset(bind_result, 0, sizeof(StunAtrAddress) * 2);

nat_type.h

@@ -76,6 +76,12 @@ typedef struct
 char* encode16(char* buf, uint16_t data);
 char* encode32(char* buf, uint32_t data);
 char* encode(char* buf, const char* data, unsigned int length);
+extern int verbose;
+
+#define verbose_log(format, ...) do {       \
+        if (verbose)                        \
+            printf(format, ##__VA_ARGS__);  \
+} while(0)
 
 nat_type detect_nat_type(const char* stun_host, uint16_t stun_port, const char* local_host, uint16_t local_port, char* ext_ip, uint16_t* ext_port);