library/net.c

/*
 *  TCP networking functions
 *
 *  Copyright (C) 2006-2010, Paul Bakker <polarssl_maintainer at polarssl.org>
 *  All rights reserved.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "polarssl/config.h"

#if defined(POLARSSL_NET_C)

#include "polarssl/net.h"

#if defined(_WIN32) || defined(_WIN32_WCE)

#include <winsock2.h>
#include <windows.h>

#if defined(_WIN32_WCE)
#pragma comment( lib, "ws2.lib" )
#else
#pragma comment( lib, "ws2_32.lib" )
#endif

#define read(fd,buf,len)        recv(fd,buf,len,0)
#define write(fd,buf,len)       send(fd,buf,len,0)
#define close(fd)               closesocket(fd)

static int wsa_init_done = 0;

#else

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <unistd.h>
#include <signal.h>
#include <fcntl.h>
#include <netdb.h>
#include <errno.h>

#if defined(__FreeBSD__)
#include <sys/endian.h>
#elif defined(__APPLE__)
#include <machine/endian.h>
#else
#include <endian.h>
#endif

#endif

#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <time.h>

/*
 * htons() is not always available.
 * By default go for LITTLE_ENDIAN variant. Otherwise hope for _BYTE_ORDER and __BIG_ENDIAN
 * to help determine endianess.
 */
#if defined(__BYTE_ORDER) && defined(__BIG_ENDIAN) && __BYTE_ORDER == __BIG_ENDIAN
#define POLARSSL_HTONS(n) (n)
#else
#define POLARSSL_HTONS(n) (((((unsigned short)(n) & 0xFF)) << 8) | (((unsigned short)(n) & 0xFF00) >> 8))
#endif

unsigned short net_htons(unsigned short n);
#define net_htons(n) POLARSSL_HTONS(n)

/*
 * Initiate a TCP connection with host:port
 */
int net_connect( int *fd, const char *host, int port )
{
    struct sockaddr_in server_addr;
    struct hostent *server_host;

#if defined(_WIN32) || defined(_WIN32_WCE)
    WSADATA wsaData;

    if( wsa_init_done == 0 )
    {
        if( WSAStartup( MAKEWORD(2,0), &wsaData ) == SOCKET_ERROR )
            return( POLARSSL_ERR_NET_SOCKET_FAILED );

        wsa_init_done = 1;
    }
#else
    signal( SIGPIPE, SIG_IGN );
#endif

    if( ( server_host = gethostbyname( host ) ) == NULL )
        return( POLARSSL_ERR_NET_UNKNOWN_HOST );

    if( ( *fd = socket( AF_INET, SOCK_STREAM, IPPROTO_IP ) ) < 0 )
        return( POLARSSL_ERR_NET_SOCKET_FAILED );

    memcpy( (void *) &server_addr.sin_addr,
            (void *) server_host->h_addr,
                     server_host->h_length );

    server_addr.sin_family = AF_INET;
    server_addr.sin_port   = net_htons( port );

    if( connect( *fd, (struct sockaddr *) &server_addr,
                 sizeof( server_addr ) ) < 0 )
    {
        close( *fd );
        return( POLARSSL_ERR_NET_CONNECT_FAILED );
    }

    return( 0 );
}

/*
 * Create a listening socket on bind_ip:port
 */
int net_bind( int *fd, const char *bind_ip, int port )
{
    int n, c[4];
    struct sockaddr_in server_addr;

#if defined(_WIN32) || defined(_WIN32_WCE)
    WSADATA wsaData;

    if( wsa_init_done == 0 )
    {
        if( WSAStartup( MAKEWORD(2,0), &wsaData ) == SOCKET_ERROR )
            return( POLARSSL_ERR_NET_SOCKET_FAILED );

        wsa_init_done = 1;
    }
#else
    signal( SIGPIPE, SIG_IGN );
#endif

    if( ( *fd = socket( AF_INET, SOCK_STREAM, IPPROTO_IP ) ) < 0 )
        return( POLARSSL_ERR_NET_SOCKET_FAILED );

    n = 1;
    setsockopt( *fd, SOL_SOCKET, SO_REUSEADDR,
                (const char *) &n, sizeof( n ) );

    server_addr.sin_addr.s_addr = INADDR_ANY;
    server_addr.sin_family      = AF_INET;
    server_addr.sin_port        = net_htons( port );

    if( bind_ip != NULL )
    {
        memset( c, 0, sizeof( c ) );
        sscanf( bind_ip, "%d.%d.%d.%d", &c[0], &c[1], &c[2], &c[3] );

        for( n = 0; n < 4; n++ )
            if( c[n] < 0 || c[n] > 255 )
                break;

        if( n == 4 )
            server_addr.sin_addr.s_addr =
                ( (unsigned long) c[0] << 24 ) |
                ( (unsigned long) c[1] << 16 ) |
                ( (unsigned long) c[2] <<  8 ) |
                ( (unsigned long) c[3]       );
    }

    if( bind( *fd, (struct sockaddr *) &server_addr,
              sizeof( server_addr ) ) < 0 )
    {
        close( *fd );
        return( POLARSSL_ERR_NET_BIND_FAILED );
    }

    if( listen( *fd, 10 ) != 0 )
    {
        close( *fd );
        return( POLARSSL_ERR_NET_LISTEN_FAILED );
    }

    return( 0 );
}

/*
 * Check if the current operation is blocking
 */
static int net_is_blocking( void )
{
#if defined(_WIN32) || defined(_WIN32_WCE)
    return( WSAGetLastError() == WSAEWOULDBLOCK );
#else
    switch( errno )
    {
#if defined EAGAIN
        case EAGAIN:
#endif
#if defined EWOULDBLOCK && EWOULDBLOCK != EAGAIN
        case EWOULDBLOCK:
#endif
            return( 1 );
    }
    return( 0 );
#endif
}

/*
 * Accept a connection from a remote client
 */
int net_accept( int bind_fd, int *client_fd, void *client_ip )
{
    struct sockaddr_in client_addr;

#if defined(__socklen_t_defined) || defined(_SOCKLEN_T)
    socklen_t n = (socklen_t) sizeof( client_addr );
#else
    int n = (int) sizeof( client_addr );
#endif

    *client_fd = accept( bind_fd, (struct sockaddr *)
                         &client_addr, &n );

    if( *client_fd < 0 )
    {
        if( net_is_blocking() != 0 )
            return( POLARSSL_ERR_NET_TRY_AGAIN );

        return( POLARSSL_ERR_NET_ACCEPT_FAILED );
    }

    if( client_ip != NULL )
        memcpy( client_ip, &client_addr.sin_addr.s_addr,
                    sizeof( client_addr.sin_addr.s_addr ) );

    return( 0 );
}

/*
 * Set the socket blocking or non-blocking
 */
int net_set_block( int fd )
{
#if defined(_WIN32) || defined(_WIN32_WCE)
    long n = 0;
    return( ioctlsocket( fd, FIONBIO, &n ) );
#else
    return( fcntl( fd, F_SETFL, fcntl( fd, F_GETFL ) & ~O_NONBLOCK ) );
#endif
}

int net_set_nonblock( int fd )
{
#if defined(_WIN32) || defined(_WIN32_WCE)
    long n = 1;
    return( ioctlsocket( fd, FIONBIO, &n ) );
#else
    return( fcntl( fd, F_SETFL, fcntl( fd, F_GETFL ) | O_NONBLOCK ) );
#endif
}

/*
 * Portable usleep helper
 */
void net_usleep( unsigned long usec )
{
    struct timeval tv;
    tv.tv_sec  = 0;
    tv.tv_usec = usec;
    select( 0, NULL, NULL, NULL, &tv );
}

/*
 * Read at most 'len' characters
 */
int net_recv( void *ctx, unsigned char *buf, int len )
{ 
    int ret = read( *((int *) ctx), buf, len );

    if( len > 0 && ret == 0 )
        return( POLARSSL_ERR_NET_CONN_RESET );

    if( ret < 0 )
    {
        if( net_is_blocking() != 0 )
            return( POLARSSL_ERR_NET_TRY_AGAIN );

#if defined(_WIN32) || defined(_WIN32_WCE)
        if( WSAGetLastError() == WSAECONNRESET )
            return( POLARSSL_ERR_NET_CONN_RESET );
#else
        if( errno == EPIPE || errno == ECONNRESET )
            return( POLARSSL_ERR_NET_CONN_RESET );

        if( errno == EINTR )
            return( POLARSSL_ERR_NET_TRY_AGAIN );
#endif

        return( POLARSSL_ERR_NET_RECV_FAILED );
    }

    return( ret );
}

/*
 * Write at most 'len' characters
 */
int net_send( void *ctx, unsigned char *buf, int len )
{
    int ret = write( *((int *) ctx), buf, len );

    if( ret < 0 )
    {
        if( net_is_blocking() != 0 )
            return( POLARSSL_ERR_NET_TRY_AGAIN );

#if defined(_WIN32) || defined(_WIN32_WCE)
        if( WSAGetLastError() == WSAECONNRESET )
            return( POLARSSL_ERR_NET_CONN_RESET );
#else
        if( errno == EPIPE || errno == ECONNRESET )
            return( POLARSSL_ERR_NET_CONN_RESET );

        if( errno == EINTR )
            return( POLARSSL_ERR_NET_TRY_AGAIN );
#endif

        return( POLARSSL_ERR_NET_SEND_FAILED );
    }

    return( ret );
}

/*
 * Gracefully close the connection
 */
void net_close( int fd )
{
    shutdown( fd, 2 );
    close( fd );
}

#endif