127.0.0.1（localhost）のUDPソケットにデータを送信するときに 'Destination unreachable'（ 'Port unreachable'）

Question

Cアプリケーションのソケット間でデータを送信します。私はまず、127.0.0.1（localhost）の特定のポートをlistenするために '受信側'をバインドします（別のスレッドでブロックします）。私はこのポートにデータを送信し始めます。 私は次のプログラムからのプリントアウトを取得：ループバックインターフェイスでのWiresharkを実行

*** Created server socket good. Server socket is 4 
(..) 
port nr 4793 & ip 127.0.0.1***Bind succeed.. 
Waiting for recvfrom() to complete... 
waiting to receive msg*** Start sending messages.. 
sendto() successs 
sendto() successs 
(..) 
sendto() successs 

を、私はパケットが正しい宛先アドレスに送信されていることがわかり。 しかし、 'Destination unreachable'（ 'Port unreachable'）というエラーが表示されます。ファイアウォールをオフにしても同じエラーが表示されます。

コードにエラーはありますか。どのように私はこれを解決するのですか？ヘッダファイルの

いくつかの定義：

#define PORT_NUM 4793 // Arbitrary port number for the server 
#define IP_ADDR  "127.0.0.1" // IP address of server1 (*** HARDWIRED ***) 
#define SYMBOL_SIZE 1024 //todo..on a different position also 

プログラム開始送信者と受信者： は、以下のコードの抜粋を以下

ret = init_sender(); 
    if (ret != OF_STATUS_OK) { 
     OF_PRINT_ERROR(("ERROR, init_sender() failed\n")) 
     goto error; 
    } 

    // >>> Step #3 <<< 
     // Wait to receive a message from client..Since receiver is waiting-do this in separate thread. 
    pthread_t thread1; 
    int iret1; 
    char *message1 = "Thread 1"; 

    iret1 = pthread_create(&thread1, NULL, init_receiver, (void*) message1); 

    ret = encode(); //this sends messages 
    if (ret != OF_STATUS_OK) { 
     OF_PRINT_ERROR(("ERROR, encode() failed\n")) 
     goto error; 
    } 


    if (ret != OF_STATUS_OK) { 
     OF_PRINT_ERROR(("ERROR, init_receiver() failed\n")) 
     goto error; 
    } //todo..ok after init_receiver? 
    ret = init_tx_simulator(); /* must be done after init_sender */ 
    if (ret != OF_STATUS_OK) { 
     OF_PRINT_ERROR(("ERROR, init_tx_simulator() failed\n")) 
     goto error; 
    } 

    print_params(); 
    //print_rx_stats(); 
#endif /* OF_DEBUG */ 
#endif 

    pthread_join (thread1, NULL); //We want the receiver thread to be finished before finishing it.. 

送信者：

of_status_t encode (void) 

{ 

     // Create a socket 
     // - AF_INET is Address Family Internet and SOCK_DGRAM is datagram 
     client_s = socket(AF_INET, SOCK_DGRAM, 0); 
     if (client_s < 0) 
     { 
     printf("*** ERROR - socket() failed \n"); 
     exit(-1); 
     } 
     printf("*** Sender -- socket created \n"); 

      printf("*** Start sending messages.. \n"); 



    // >>> Step #2 <<< 
     // Fill-in server1 socket's address information 
     server_addr.sin_family = AF_INET;     // Address family to use 
     server_addr.sin_port = htons(PORT_NUM);   // Port num to use 
     server_addr.sin_addr.s_addr = inet_addr(IP_ADDR); // IP address to use 


    //n is number of symbols to sent -- repair + original.. 
int j= 0; 
    for (j=0; j < 10 ; j++) 
     { 
     retcode = sendto(client_s, (const void*) encoding_symbols_tab[j], symbol_size, 0, 
     (struct sockaddr *)&server_addr, sizeof(server_addr)); 

     if (retcode < 0) 
     { 
     // printf("*** ERROR - sendto() failed.. retcode is %d \n", retcode); 
     printf ("errno is %s",strerror (errno));   
     exit(-1); 
     } 
     else 
     printf("sendto() successs \n"); 

     } 

retcode = close(client_s); 
    if (retcode < 0) 
    { 
    printf("*** ERROR - close() failed \n"); 
    exit(-1); 

レシーバ。

init_receive() { 


      // >>> Step #1 <<< 
      // Create a socket 
      // - AF_INET is Address Family Internet and SOCK_DGRAM is datagram 
      server_s = socket(AF_INET, SOCK_DGRAM, 0); 
      if (server_s < 0) 
      { 
      printf("*** ERROR - socket() failed \n"); 
      exit(-1); 
      } 
      else 
      printf("*** Created server socket good. Server socket is %d \n", server_s); 


      // >>> Step #2 <<< 
      // Fill-in my socket's address information 
      server_addr.sin_family = AF_INET;     // Address family to use 
      server_addr.sin_port = htons(PORT_NUM);   // Port number to use 
      server_addr.sin_addr.s_addr = htonl(IP_ADDR); // Listen on this IP.. 
      printf("***We have a server socket; and now we will try to bind it with the IP_ADDR-local host -- that we sent.. \n port nr %d & ip %s", PORT_NUM, IP_ADDR); 

      retcode = bind(server_s, (struct sockaddr *)&server_addr, 
      sizeof(server_addr)); 

      if (retcode < 0) 
      { 
      printf("*** ERROR - bind() failed \n"); 
      exit(-1); 
      } 
     else 
      printf("***Bind succeed.. \n"); 


     waitToReceiveMessageFromClient(); //call it and wait to receive messages. 

     return OF_STATUS_OK; 

    no_mem: 
     return OF_STATUS_ERROR; 
    } 

waitToReeiveMessageFromClient() { 

int 
waitToReceiveMessageFromClient (void) 
{ 
     printf("Waiting for recvfrom() to complete... \n"); 
     addr_len = sizeof(client_addr); 
    encoding_symbols_tab = (void*) calloc(MAX_N, sizeof(void*)); 
    int i = 0; 
    //Run until we have finished all messages from the Sender. 

     while (numberMessagesReceivedCounter < tot_nb_source_symbols + tot_nb_repair_symbols) 
     { 
     printf ("waiting to receive msg"); 

     encoding_symbols_tab[i] = (void*)calloc(1, SYMBOL_SIZE); //each 
//change to non-blocking 
//if(fcntl(server_s, F_SETFL, fcntl(server_s, F_GETFL) | O_NONBLOCK) < 0) { 
    // printf ("error for the moment"); 
//} 

      retcode = recvfrom(server_s, in_buf, sizeof(in_buf), 0, 
      (struct sockaddr *)&client_addr, &addr_len); 

      if (retcode < 0) 
      { 
      fprintf (stderr,"errno is %d", errno); 
      exit(-1); 
      } 
      else 
      { //copy all symbols to its right location from received message. 
     printf("*** Received message.. \n"); 

      int k= 0; 
      for (k= 0; k < sizeof (in_buf) ; k++) 
      { 
      encoding_symbols_tab[numberMessagesReceivedCounter][k] = (char*) in_buf[k]; 
      } 
      numberMessagesReceivedCounter++; 

      //Finished ready to do decoding. 
      if (numberMessagesReceivedCounter == tot_nb_source_symbols + tot_nb_repair_symbols) 
      { 
      receive_and_decode(); 
      break; 
      } 

      } 
     } 
    //add to buffer... numberMessagesReceivedCounter 

} 



} 

Answer 1

（送信側で）この行：

は正しいです。

この線（受信機で）：

server_addr.sin_addr.s_addr = htonl(IP_ADDR); 

が間違っています。ちょっと驚いたことに、それはきれいにコンパイルされました（またはそれをしましたか？）。