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POHops tracing ttl reciveform on ios
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copied!<p>I'm trying to implement simple traceroute for the iOS. Everything seems to work fine, except that somehow when I run my application on simulator or on the device it finds only a few (6-7) first routers on the way when the CLI traceroute finds all 14 routers.</p> <pre><code>const char *c = "www.gmail.com"; struct hostent *host_entry = gethostbyname(c); char *ip_addr; ip_addr = inet_ntoa(*((struct in_addr *)host_entry->h_addr_list[0])); struct sockaddr_in destination, fromAddr; int recv_sock; int send_sock; // Creting Sockets/// if ((recv_sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP)) < 0) // using UDP socket. { NSLog(@"Could not cretae recv_sock.\n"); } if ((send_sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { NSLog(@"Could not cretae send_sock.\n"); } memset(&destination, 0, sizeof(destination)); destination.sin_family = AF_INET; destination.sin_addr.s_addr = inet_addr(ip_addr); destination.sin_port = htons(80); struct timeval tv; tv.tv_sec = 0; tv.tv_usec = 10000; setsockopt(recv_sock, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv, sizeof(struct timeval)); char *cmsg = "GET / HTTP/1.1\r\n\r\n"; int max_ttl = 20; int num_attempts = 5; socklen_t n = sizeof(fromAddr); char buf[100]; for (int ttl = 1; ttl <= max_ttl; ttl++) { memset(&fromAddr, 0, sizeof(fromAddr)); if (setsockopt(send_sock, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl)) < 0) NSLog(@"error in setsockopt\n"); for (int try = 0; try < num_attempts; try ++) { if (sendto(send_sock, cmsg, sizeof(cmsg), 0, (struct sockaddr *)&destination, sizeof(destination)) != sizeof(cmsg)) NSLog(@"error in send to...\n@"); int res = 0; if ((res = recvfrom(recv_sock, buf, 100, 0, (struct sockaddr *)&fromAddr, &n)) < 0) { NSLog(@"an error: %s; recvfrom returned %d\n", strerror(errno), res); } else { char display[16] = {0}; inet_ntop(AF_INET, &fromAddr.sin_addr.s_addr, display, sizeof(display)); NSLog(@"Received packet from%s for TTL=%d\n", display, ttl); break; } } } </code></pre> <p>I have tried to bind the send socket but have same results and I can't use Sock_raw on iOS. I tried to run it on my mac and got same results. The error I get is "Resource temporarily unavailable;" for the <code>recvfrom()</code>. Why is that? How can I fix it?</p>

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