blob: 04f7f6da0d559078cff969a9c3daa405f8252f28 [file] [log] [blame]
/*
* proxy-polarssl.c - Net stack layer for SOCKS4a/5 proxy connections
*
* Based on proxy-bio.c - Original copyright (c) 2012 The Chromium OS Authors.
*
* This file was adapted by Paul Bakker <p.j.bakker@offspark.com>
* All rights reserved.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
* This file implements a SOCKS4a/SOCKS5 net layer as used by PolarSSL.
*/
#include "config.h"
#include <arpa/inet.h>
#include <assert.h>
#ifndef __USE_MISC
#define __USE_MISC
#endif
#ifndef __USE_POSIX
#define __USE_POSIX
#endif
#include <netdb.h>
#include <stdint.h>
#include <stdio.h>
#ifndef HAVE_STRNLEN
#include "src/common/strnlen.h"
#endif
#include "src/proxy-polarssl.h"
#include "src/util.h"
int socks4a_connect(proxy_polarssl_ctx *ctx)
{
int r;
unsigned char buf[NI_MAXHOST + 16];
uint16_t port_n;
size_t sz = 0;
if (!ctx)
return 0;
verb("V: proxy4: connecting %s:%d", ctx->host, ctx->port);
port_n = htons(ctx->port);
/*
* Packet layout:
* 1b: Version (must be 0x04)
* 1b: command (0x01 is connect)
* 2b: port number, big-endian
* 4b: 0x00, 0x00, 0x00, 0x01 (bogus IPv4 addr)
* 1b: 0x00 (empty 'userid' field)
* nb: hostname, null-terminated
*/
buf[0] = 0x04;
buf[1] = 0x01;
sz += 2;
memcpy(buf + 2, &port_n, sizeof(port_n));
sz += sizeof(port_n);
buf[4] = 0x00;
buf[5] = 0x00;
buf[6] = 0x00;
buf[7] = 0x01;
sz += 4;
buf[8] = 0x00;
sz += 1;
memcpy(buf + sz, ctx->host, strlen(ctx->host) + 1);
sz += strlen(ctx->host) + 1;
r = ctx->f_send(ctx->p_send, buf, sz);
if (r != sz)
return 0;
/* server reply: 1 + 1 + 2 + 4 */
r = ctx->f_recv(ctx->p_recv, buf, 8);
if (r != 8)
return 0;
if (buf[1] == 0x5a) {
verb("V: proxy4: connected");
ctx->connected = 1;
return 1;
}
return 0;
}
int socks5_connect(proxy_polarssl_ctx *ctx)
{
unsigned char buf[NI_MAXHOST + 16];
int r;
uint16_t port_n;
size_t sz = 0;
if (!ctx)
return 0;
/* the length for SOCKS addresses is only one byte. */
if (strnlen(ctx->host, UINT8_MAX + 1) == UINT8_MAX + 1)
return 0;
verb("V: proxy5: connecting %s:%d", ctx->host, ctx->port);
port_n = htons(ctx->port);
/*
* Hello packet layout:
* 1b: Version
* 1b: auth methods
* nb: method types
*
* We support only one method (no auth, 0x00). Others listed in RFC
* 1928.
*/
buf[0] = 0x05;
buf[1] = 0x01;
buf[2] = 0x00;
r = ctx->f_send(ctx->p_send, buf, 3);
if (r != 3)
return 0;
r = ctx->f_recv(ctx->p_recv, buf, 2);
if (r != 2)
return 0;
if (buf[0] != 0x05 || buf[1] != 0x00) {
verb("V: proxy5: auth error %02x %02x", buf[0], buf[1]);
return 0;
}
/*
* Connect packet layout:
* 1b: version
* 1b: command (0x01 is connect)
* 1b: reserved, 0x00
* 1b: addr type (0x03 is domain name)
* nb: addr len (1b) + addr bytes, no null termination
* 2b: port, network byte order
*/
buf[0] = 0x05;
buf[1] = 0x01;
buf[2] = 0x00;
buf[3] = 0x03;
buf[4] = strlen(ctx->host);
sz += 5;
memcpy(buf + 5, ctx->host, strlen(ctx->host));
sz += strlen(ctx->host);
memcpy(buf + sz, &port_n, sizeof(port_n));
sz += sizeof(port_n);
r = ctx->f_send(ctx->p_send, buf, sz);
if (r != sz)
return 0;
/*
* Server's response:
* 1b: version
* 1b: status (0x00 is okay)
* 1b: reserved, 0x00
* 1b: addr type (0x03 is domain name, 0x01 ipv4)
* nb: addr len (1b) + addr bytes, no null termination
* 2b: port, network byte order
*/
/* grab up through the addr type */
r = ctx->f_recv(ctx->p_recv, buf, 4);
if (r != 4)
return 0;
if (buf[0] != 0x05 || buf[1] != 0x00) {
verb("V: proxy5: connect error %02x %02x", buf[0], buf[1]);
return 0;
}
if (buf[3] == 0x03) {
unsigned int len;
r = ctx->f_recv(ctx->p_recv, buf + 4, 1);
if (r != 1)
return 0;
/* host (buf[4] bytes) + port (2 bytes) */
len = buf[4] + 2;
while (len) {
r = ctx->f_recv(ctx->p_recv, buf + 5, min(len, sizeof(buf)));
if (r <= 0)
return 0;
len -= min(len, r);
}
} else if (buf[3] == 0x01) {
/* 4 bytes ipv4 addr, 2 bytes port */
r = ctx->f_recv(ctx->p_recv, buf + 4, 6);
if (r != 6)
return 0;
}
verb("V: proxy5: connected");
ctx->connected = 1;
return 1;
}
/* SSL socket BIOs don't support BIO_gets, so... */
int sock_gets(proxy_polarssl_ctx *ctx, char *buf, size_t sz)
{
unsigned char c;
while (ctx->f_recv(ctx->p_recv, &c, 1) > 0 && sz > 1) {
*buf++ = c;
sz--;
if (c == '\n') {
*buf = '\0';
return 0;
}
}
return 1;
}
int http_connect(proxy_polarssl_ctx *ctx)
{
int r;
char buf[4096];
int retcode;
snprintf(buf, sizeof(buf), "CONNECT %s:%d HTTP/1.1\r\n",
ctx->host, ctx->port);
r = ctx->f_send(ctx->p_send, (unsigned char *) buf, strlen(buf));
if (r != strlen(buf))
return 0;
/* required by RFC 2616 14.23 */
snprintf(buf, sizeof(buf), "Host: %s:%d\r\n", ctx->host, ctx->port);
r = ctx->f_send(ctx->p_send, (unsigned char *) buf, strlen(buf));
if (r != strlen(buf))
return 0;
strcpy(buf, "\r\n");
r = ctx->f_send(ctx->p_send, (unsigned char *) buf, strlen(buf));
if (r != strlen(buf))
return 0;
r = sock_gets(ctx, buf, sizeof(buf));
if (r)
return 0;
/* use %*s to ignore the version */
if (sscanf(buf, "HTTP/%*s %d", &retcode) != 1)
return 0;
if (retcode < 200 || retcode > 299)
return 0;
while (!(r = sock_gets(ctx, buf, sizeof(buf)))) {
if (!strcmp(buf, "\r\n")) {
/* Done with the header */
ctx->connected = 1;
return 1;
}
}
return 0;
}
int API proxy_polarssl_init(proxy_polarssl_ctx *ctx)
{
if (!ctx)
return 0;
memset(ctx, 0, sizeof(proxy_polarssl_ctx));
return 1;
}
void API proxy_polarssl_set_bio(proxy_polarssl_ctx *ctx,
int (*f_recv)(void *, unsigned char *, size_t), void *p_recv,
int (*f_send)(void *, const unsigned char *, size_t), void *p_send)
{
if (!ctx)
return;
ctx->f_recv = f_recv;
ctx->p_recv = p_recv;
ctx->f_send = f_send;
ctx->p_send = p_send;
}
int API proxy_polarssl_free(proxy_polarssl_ctx *ctx)
{
if (!ctx)
return 0;
if (ctx->host)
{
free(ctx->host);
ctx->host = NULL;
}
return 1;
}
int API proxy_polarssl_set_scheme(proxy_polarssl_ctx *ctx, const char *scheme)
{
if (!strcmp(scheme, "socks5"))
ctx->f_connect = socks5_connect;
else if (!strcmp(scheme, "socks4"))
ctx->f_connect = socks4a_connect;
else if (!strcmp(scheme, "http"))
ctx->f_connect = http_connect;
else
return 1;
return 0;
}
int API proxy_polarssl_set_host(proxy_polarssl_ctx *ctx, const char *host)
{
if (strnlen(host, NI_MAXHOST) == NI_MAXHOST)
return 1;
ctx->host = strdup(host);
return 0;
}
void API proxy_polarssl_set_port(proxy_polarssl_ctx *ctx, uint16_t port)
{
ctx->port = port;
}
int API proxy_polarssl_recv(void *ctx, unsigned char *data, size_t len)
{
proxy_polarssl_ctx *proxy = (proxy_polarssl_ctx *) ctx;
int r;
if (!ctx)
return -1;
if (!proxy->connected)
{
r = proxy->f_connect(ctx);
if (r)
return (r);
}
return proxy->f_recv(proxy->p_recv, data, len);
}
int API proxy_polarssl_send(void *ctx, const unsigned char *data, size_t len)
{
proxy_polarssl_ctx *proxy = (proxy_polarssl_ctx *) ctx;
int r;
if (!ctx)
return -1;
if (!proxy->connected)
{
r = proxy->f_connect(ctx);
if (r)
return (r);
}
return proxy->f_send(proxy->p_send, data, len);
}