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#include "gen.h"
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/time.h>
#include <time.h>
#include <netdb.h>
#include <arpa/inet.h>
#include "error.h"
#include "gen.h"
#include "io.h"
#include "res.h"
#include "tcp.h"
int socks5connect(int fd, struct addrinfo *ai, double timeout, const char *socks5_username, const char *socks5_password, const char *host, int port, char abort_on_resolve_failure)
{
struct sockaddr_in sai;
uint32_t addr = 0;
unsigned char io_buffer[256] = { 0 };
int io_len = 0, rc = -1;
if ((rc = connect_to(fd, ai, timeout, NULL, NULL, 0, NULL)) == -1)
return rc;
/* inform socks server about the auth. methods we support */
if (socks5_username != NULL)
{
io_buffer[0] = 0x05; /* version */
io_buffer[1] = 2; /* 2 authentication methods */
io_buffer[2] = 0x00; /* method 1: no authentication */
io_buffer[3] = 0x02; /* method 2: username/password */
io_len = 4;
}
else
{
io_buffer[0] = 0x05; /* version */
io_buffer[1] = 1; /* 2 authentication methods */
io_buffer[2] = 0x00; /* method 1: no authentication */
io_len = 3;
}
if ((rc = mywrite(fd, (char *)io_buffer, io_len, timeout)) < 0)
return rc;
/* wait for reply telling selected authentication method */
if ((rc = myread(fd, (char *)io_buffer, 2, timeout)) < 0)
return rc;
if (io_buffer[0] != 0x05)
{
set_error(gettext("socks5connect: reply with requested authentication method does not say version 5 (%02x)"), io_buffer[0]);
return RC_INVAL;
}
if (io_buffer[1] == 0x00)
{
/* printf("socks5connect: \"no authentication at all\" selected by server\n"); */
}
else if (io_buffer[1] == 0x02)
{
/* printf("socks5connect: selected username/password authentication\n"); */
}
else
{
set_error(gettext("socks5connect: socks5 refuses our authentication methods: %02x"), io_buffer[1]);
return RC_INVAL;
}
/* in case the socks5 server asks us to authenticate, do so */
if (io_buffer[1] == 0x02)
{
int io_len = 0;
if (socks5_username == NULL || socks5_password == NULL)
{
set_error(gettext("socks5connect: socks5 server requests username/password authentication"));
return RC_INVAL;
}
io_buffer[0] = 0x01; /* version */
io_len = snprintf((char *)&io_buffer[1], sizeof io_buffer - 1, "%c%s%c%s", (int)strlen(socks5_username), socks5_username, (int)strlen(socks5_password), socks5_password);
if ((rc = mywrite(fd, (char *)io_buffer, io_len + 1, timeout)) < 0)
{
set_error(gettext("socks5connect: failed transmitting username/password to socks5 server"));
return rc;
}
if ((rc = myread(fd, (char *)io_buffer, 2, timeout)) < 0)
{
set_error(gettext("socks5connect: failed receiving authentication reply"));
return rc;
}
if (io_buffer[1] != 0x00)
{
set_error(gettext("socks5connect: password authentication failed"));
return RC_INVAL;
}
}
/* ask socks5 server to associate with server */
io_buffer[0] = 0x05; /* version */
io_buffer[1] = 0x01; /* connect to */
io_buffer[2] = 0x00; /* reserved */
io_buffer[3] = 0x01; /* ipv4 */
if (resolve_host_ipv4(host, &sai) == -1)
{
if (abort_on_resolve_failure)
error_exit(gettext("Cannot resolve %s"), host);
return RC_INVAL;
}
addr = ntohl(sai.sin_addr.s_addr);
io_buffer[4] = (addr >> 24) & 255;
io_buffer[5] = (addr >> 16) & 255;
io_buffer[6] = (addr >> 8) & 255;
io_buffer[7] = (addr ) & 255;
io_buffer[8] = (port >> 8) & 255;
io_buffer[9] = (port ) & 255;
if ((rc = mywrite(fd, (char *)io_buffer, 10, timeout)) < 0)
{
set_error(gettext("socks5connect: failed to transmit associate request"));
return rc;
}
if ((rc = myread(fd, (char *)io_buffer, 10, timeout)) < 0)
{
set_error(gettext("socks5connect: command reply receive failure"));
return rc;
}
/* verify reply */
if (io_buffer[0] != 0x05)
{
set_error(gettext("socks5connect: bind request replies with version other than 0x05 (%02x)"), io_buffer[0]);
return RC_INVAL;
}
if (io_buffer[1] != 0x00)
{
set_error(gettext("socks5connect: failed to connect (%02x)"), io_buffer[1]);
return RC_INVAL;
}
if (io_buffer[3] != 0x01)
{
set_error(gettext("socks5connect: only accepting bind-replies with IPv4 address (%02x)"), io_buffer[3]);
return RC_INVAL;
}
return RC_OK;
}
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