1 /* $OpenBSD: socks.c,v 1.3 2001/10/28 19:46:12 jakob Exp $ */ 2 3 /* 4 * Copyright (c) 1999 Niklas Hallqvist. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Niklas Hallqvist. 17 * 4. The name of the author may not be used to endorse or promote products 18 * derived from this software without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 23 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/types.h> 33 #include <sys/socket.h> 34 #include <netinet/in.h> 35 #include <arpa/inet.h> 36 37 #include <err.h> 38 #include <netdb.h> 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <string.h> 42 #include <unistd.h> 43 44 #define SOCKS_PORT "1080" 45 #define SOCKS_VERSION 5 46 #define SOCKS_NOAUTH 0 47 #define SOCKS_NOMETHOD 0xff 48 #define SOCKS_CONNECT 1 49 #define SOCKS_IPV4 1 50 #define SOCKS_MAXCMDSZ 10 51 52 static in_addr_t 53 decode_addr (const char *s) 54 { 55 struct hostent *hp = gethostbyname (s); 56 struct in_addr retval; 57 58 if (hp) 59 return *(in_addr_t *)hp->h_addr_list[0]; 60 if (inet_aton (s, &retval)) 61 return retval.s_addr; 62 errx (1, "cannot decode address \"%s\"", s); 63 } 64 65 static in_port_t 66 decode_port (const char *s) 67 { 68 struct servent *sp; 69 in_port_t port; 70 char *p; 71 72 port = strtol (s, &p, 10); 73 if (s == p) { 74 sp = getservbyname (s, "tcp"); 75 if (sp) 76 return sp->s_port; 77 } 78 if (*s != '\0' && *p == '\0') 79 return htons (port); 80 errx (1, "cannot decode port \"%s\"", s); 81 } 82 83 int 84 socks_connect (char *host, char *port, struct addrinfo hints, 85 char *proxyhost, char *proxyport, struct addrinfo proxyhints) 86 { 87 int proxyfd; 88 unsigned char buf[SOCKS_MAXCMDSZ]; 89 ssize_t cnt; 90 in_addr_t serveraddr; 91 in_port_t serverport; 92 93 if (proxyport) 94 proxyfd = remote_connect(proxyhost, proxyport, proxyhints); 95 else 96 proxyfd = remote_connect(proxyhost, SOCKS_PORT, proxyhints); 97 98 if (!proxyfd) 99 return -1; 100 101 serveraddr = decode_addr (host); 102 serverport = decode_port (port); 103 104 /* Version 5, one method: no authentication */ 105 buf[0] = SOCKS_VERSION; 106 buf[1] = 1; 107 buf[2] = SOCKS_NOAUTH; 108 cnt = write (proxyfd, buf, 3); 109 if (cnt == -1) 110 err (1, "write failed"); 111 if (cnt != 3) 112 errx (1, "short write, %d (expected 3)", cnt); 113 114 read (proxyfd, buf, 2); 115 if (buf[1] == SOCKS_NOMETHOD) 116 errx (1, "authentication method negotiation failed"); 117 118 /* Version 5, connect: IPv4 address */ 119 buf[0] = SOCKS_VERSION; 120 buf[1] = SOCKS_CONNECT; 121 buf[2] = 0; 122 buf[3] = SOCKS_IPV4; 123 memcpy (buf + 4, &serveraddr, sizeof serveraddr); 124 memcpy (buf + 8, &serverport, sizeof serverport); 125 126 /* XXX Handle short writes better */ 127 cnt = write (proxyfd, buf, 10); 128 if (cnt == -1) 129 err (1, "write failed"); 130 if (cnt != 10) 131 errx (1, "short write, %d (expected 10)", cnt); 132 133 /* XXX Handle short reads better */ 134 cnt = read (proxyfd, buf, sizeof buf); 135 if (cnt == -1) 136 err (1, "read failed"); 137 if (cnt != 10) 138 errx (1, "unexpected reply size %d (expected 10)", cnt); 139 if (buf[1] != 0) 140 errx (1, "connection failed, SOCKS error %d", buf[1]); 141 142 return proxyfd; 143 } 144