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/* $OpenBSD: socks.c,v 1.9 2004/10/17 03:13:55 djm Exp $ */
/*
* Copyright (c) 1999 Niklas Hallqvist. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <err.h>
#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define SOCKS_PORT "1080"
#define HTTP_PROXY_PORT "3128"
#define HTTP_MAXHDRS 64
#define SOCKS_V5 5
#define SOCKS_V4 4
#define SOCKS_NOAUTH 0
#define SOCKS_NOMETHOD 0xff
#define SOCKS_CONNECT 1
#define SOCKS_IPV4 1
int remote_connect(char *, char *, struct addrinfo);
int socks_connect(char *host, char *port, struct addrinfo hints,
char *proxyhost, char *proxyport, struct addrinfo proxyhints,
int socksv);
static in_addr_t
decode_addr(const char *s)
{
struct hostent *hp = gethostbyname (s);
struct in_addr retval;
if (hp)
return *(in_addr_t *)hp->h_addr_list[0];
if (inet_aton (s, &retval))
return retval.s_addr;
errx (1, "cannot decode address \"%s\"", s);
}
static in_port_t
decode_port(const char *s)
{
struct servent *sp;
in_port_t port;
char *p;
port = strtol (s, &p, 10);
if (s == p) {
sp = getservbyname (s, "tcp");
if (sp)
return sp->s_port;
}
if (*s != '\0' && *p == '\0')
return htons (port);
errx (1, "cannot decode port \"%s\"", s);
}
static int
proxy_read_line(int fd, char *buf, int bufsz)
{
int r, off;
for(off = 0;;) {
if (off >= bufsz)
errx(1, "proxy read too long");
if ((r = read(fd, buf + off, 1)) <= 0) {
if (r == -1 && errno == EINTR)
continue;
err(1, "proxy read");
}
/* Skip CR */
if (buf[off] == '\r')
continue;
if (buf[off] == '\n') {
buf[off] = '\0';
break;
}
off++;
}
return (off);
}
int
socks_connect(char *host, char *port, struct addrinfo hints,
char *proxyhost, char *proxyport, struct addrinfo proxyhints,
int socksv)
{
int proxyfd, r;
unsigned char buf[1024];
ssize_t cnt;
in_addr_t serveraddr;
in_port_t serverport;
if (proxyport == NULL)
proxyport = (socksv == -1) ? HTTP_PROXY_PORT : SOCKS_PORT;
proxyfd = remote_connect(proxyhost, proxyport, proxyhints);
if (proxyfd < 0)
return -1;
serveraddr = decode_addr (host);
serverport = decode_port (port);
if (socksv == 5) {
/* Version 5, one method: no authentication */
buf[0] = SOCKS_V5;
buf[1] = 1;
buf[2] = SOCKS_NOAUTH;
cnt = write (proxyfd, buf, 3);
if (cnt == -1)
err (1, "write failed");
if (cnt != 3)
errx (1, "short write, %d (expected 3)", cnt);
read (proxyfd, buf, 2);
if (buf[1] == SOCKS_NOMETHOD)
errx (1, "authentication method negotiation failed");
/* Version 5, connect: IPv4 address */
buf[0] = SOCKS_V5;
buf[1] = SOCKS_CONNECT;
buf[2] = 0;
buf[3] = SOCKS_IPV4;
memcpy (buf + 4, &serveraddr, sizeof serveraddr);
memcpy (buf + 8, &serverport, sizeof serverport);
/* XXX Handle short writes better */
cnt = write (proxyfd, buf, 10);
if (cnt == -1)
err (1, "write failed");
if (cnt != 10)
errx (1, "short write, %d (expected 10)", cnt);
/* XXX Handle short reads better */
cnt = read (proxyfd, buf, sizeof buf);
if (cnt == -1)
err (1, "read failed");
if (cnt != 10)
errx (1, "unexpected reply size %d (expected 10)", cnt);
if (buf[1] != 0)
errx (1, "connection failed, SOCKS error %d", buf[1]);
} else if (socksv == 4) {
/* Version 4 */
buf[0] = SOCKS_V4;
buf[1] = SOCKS_CONNECT; /* connect */
memcpy (buf + 2, &serverport, sizeof serverport);
memcpy (buf + 4, &serveraddr, sizeof serveraddr);
buf[8] = 0; /* empty username */
cnt = write (proxyfd, buf, 9);
if (cnt == -1)
err (1, "write failed");
if (cnt != 9)
errx (1, "short write, %d (expected 9)", cnt);
/* XXX Handle short reads better */
cnt = read (proxyfd, buf, 8);
if (cnt == -1)
err (1, "read failed");
if (cnt != 8)
errx (1, "unexpected reply size %d (expected 8)", cnt);
if (buf[1] != 90)
errx (1, "connection failed, SOCKS error %d", buf[1]);
} else if (socksv == -1) {
/* HTTP proxy CONNECT */
/* Disallow bad chars in hostname */
if (strcspn(host, "\r\n\t []:") != strlen(host))
errx (1, "Invalid hostname");
/* Try to be sane about numeric IPv6 addresses */
if (strchr(host, ':') != NULL) {
r = snprintf(buf, sizeof(buf),
"CONNECT [%s]:%d HTTP/1.0\r\n\r\n",
host, ntohs(serverport));
} else {
r = snprintf(buf, sizeof(buf),
"CONNECT %s:%d HTTP/1.0\r\n\r\n",
host, ntohs(serverport));
}
if (r == -1 || r >= sizeof(buf))
errx (1, "hostname too long");
r = strlen(buf);
/* XXX atomicio */
cnt = write (proxyfd, buf, r);
if (cnt == -1)
err (1, "write failed");
if (cnt != r)
errx (1, "short write, %d (expected %d)", cnt, r);
/* Read reply */
for (r = 0; r < HTTP_MAXHDRS; r++) {
proxy_read_line(proxyfd, buf, sizeof(buf));
if (r == 0 && strncmp(buf, "HTTP/1.0 200 ", 12) != 0)
errx (1, "Proxy error: \"%s\"", buf);
/* Discard headers until we hit an empty line */
if (*buf == '\0')
break;
}
} else
errx (1, "Unknown proxy protocol %d", socksv);
return proxyfd;
}
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