Question

我有一个正常的客户端 - 服务器通信，就像Beej的指南insructs来做这些事情。

服务器发送一个字符串，但是在客户端的recv中，虽然返回的值是ok（即等于从服务器发送的字节数），但是收到的字符非常奇怪，并且strlen在接收到的字符串上返回的值小于recv。返回的值

这对我来说似乎很奇怪，所以如果你能给我一个提示，那就太好了。

这是服务器代码的一部分：

    s_gateway_server = socket( PF_INET, SOCK_STREAM, 0 );

    memset( &server, 0, sizeof( server ) ); // asiguram padding-ul
    server.sin_family = AF_INET;
    server.sin_port = htons( is.port );
    inet_pton( AF_INET, is.ip, &server.sin_addr );

    status = connect( s_gateway_server, ( struct sockaddr* ) &server, sizeof( server ) );
    if( status == -1 )
    {
        printf( "ERROR\nNu te-ai putut conecta la server-ul %s :-(\n", is.ip );
        goto exit;
    }

    l = strlen( msg ) + 1;
    status = send( s_gateway_server, &msg, l, 0 );
    if( status == -1 )
    {
        perror( "ERROR\nla send catre server" );
        goto exit;
    }
    if( status < l )
    {
        //TODO trimite restul de pachet 
        printf( "ERROR\npachet ajuns incomplet la server\n" ); 
        goto exit;
    }

    printf( "Am trimis %d octeti: %s\n", status, msg );

这是客户代码的一部分：

void send_and_receive( int sock )
{
int status, ret;

while( 1 )
{
    char receivebuff[500];

    status = recv( sock, &receivebuff, 500, 0 );
    if( status == -1 )
    {
        perror( "ERROR\nla recv" );
        continue;
    }
    if( status == 0 )
        // connection closed
        break;

（没有粘贴所有函数），并在main（）中调用该函数：

int main( int argc, char **argv )
{
int s_server_gateway, conn_s_server_gateway, ret;
struct sockaddr_in gateway;
socklen_t length;

ret = parse_arg(argc, argv);
if( ret )
    return 1;

s_server_gateway = listen_to_clients();
if( s_server_gateway < 0 )
    return 2;

while( 1 )
{
    length = sizeof( gateway );
    conn_s_server_gateway = accept( s_server_gateway, ( struct sockaddr * ) &gateway, &length );

    if( conn_s_server_gateway == -1 )
    {
        perror( "ERROR\nla accept de la gateway" );
        continue;
    }

    if( !fork() )
    {
        close( s_server_gateway );

        send_and_receive( conn_s_server_gateway );

        return 0;
    }
    else
    {
        close( conn_s_server_gateway );

        continue;
    }
}

close( s_server_gateway ); 
return 0;
}


int listen_to_clients()
{
int s_server_gateway, optval, ret;
struct sockaddr_in server;

s_server_gateway = socket( PF_INET, SOCK_STREAM, 0 );
if( s_server_gateway == -1 )
{
    perror( "ERROR\nla deschidere socket" );
    return -1;
}

memset( &server, 0, sizeof( server ) ); // asiguram padding-ul
server.sin_family = AF_INET;
server.sin_port = htons( port );
inet_pton( AF_INET, "127.0.0.1", &server.sin_addr );

optval = 1;
ret = setsockopt( s_server_gateway, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof( int ) );
if( ret == -1 )
{
    perror( "ERROR\nla setsockopt" );
    close( s_server_gateway );
    return -2;
}

ret = bind( s_server_gateway, ( struct sockaddr * ) &server, sizeof( server ) );
if( ret == -1 )
{
    perror( "ERROR\nla bind" );
    close( s_server_gateway );
    return -3;
}

listen( s_server_gateway, BACKLOG );
if( ret == -1 )
{
    perror( "ERROR\nla listen" );
    close( s_server_gateway );
    return -4;
}

return s_server_gateway;
}

Answer 1

recv()

的参数不正确

char receivebuff[500];
// status = recv( sock, &receivebuff, 500, 0 )
status = recv( sock, receivebuff, 500, 0 ); // no &
// or better
status = recv( sock, receivebuff, sizeof(receivebuff), 0 );

客户端从服务器接收奇怪的字符，原始消息根本不存在

1 个答案: