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Annotation of src/usr.bin/nc/socks.c, Revision 1.2

1.2     ! jakob       1: *      $OpenBSD: socks.c,v 1.1 2001/09/02 18:45:41 jakob Exp $ */
1.1       jakob       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: }