1 /* $OpenBSD: kqueue-tun.c,v 1.5 2016/09/20 23:05:27 bluhm Exp $ */
2 /* $Gateweaver: tunkq.c,v 1.2 2003/11/27 22:47:41 cmaxwell Exp $ */
3 /*
4 * Copyright 2003 Christopher J. Maxwell <cmaxwell@themanor.net>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 #include <sys/types.h>
31 #include <sys/socket.h>
32 #include <sys/uio.h>
33
34 #include <netinet/in.h>
35 #include <net/if.h>
36 #include <net/if_tun.h>
37
38 #include <err.h>
39 #include <errno.h>
40 #include <event.h>
41 #include <fcntl.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <unistd.h>
45
46 #include "main.h"
47
48 #define TUN0 "tun98"
49 #define TUN1 "tun99"
50 #define TUN0_ADDR "192.0.2.1"
51 #define TUN1_ADDR "192.0.2.2"
52 #define TUN_MAXWAIT 5
53 #define TUN_PINGDEL 1
54
55 struct buffer {
56 u_char *buf;
57 size_t len;
58 size_t a;
59 };
60
61 int state;
62 int tunfd[2];
63 struct buffer tpkt;
64 u_char pktbuf[TUNMTU];
65 struct event tunwev[2];
66 struct timeval exittv = {TUN_MAXWAIT, 0};
67
68 void
tunnel_write(int fd,short which,void * arg)69 tunnel_write(int fd, short which, void *arg)
70 {
71 uint32_t type = htonl(AF_INET);
72 struct iovec iv[2];
73 int rlen;
74 int fdkey = (fd == tunfd[0]) ? 0 : 1;
75
76 iv[0].iov_base = &type;
77 iv[0].iov_len = sizeof(type);
78 iv[1].iov_base = tpkt.buf;
79 iv[1].iov_len = tpkt.len;
80
81 state++;
82 if ((rlen = writev(fd, iv, 2)) > 0)
83 fprintf(stderr, "Tunnel %d wrote %ld bytes\n",
84 fdkey, (long)(rlen - sizeof(type)));
85 else
86 errx(1, "Write to tunnel %d failed", fdkey);
87 }
88
89 void
tunnel_read(int fd,short which,void * arg)90 tunnel_read(int fd, short which, void *arg)
91 {
92 struct iovec iv[2];
93 uint32_t type;
94 int rlen;
95 int fdkey = (fd == tunfd[0]) ? 0 : 1;
96 int oppfdkey = (fd == tunfd[0]) ? 1 : 0;
97
98 iv[0].iov_base = &type;
99 iv[0].iov_len = sizeof(type);
100 iv[1].iov_base = tpkt.buf;
101 iv[1].iov_len = tpkt.a;
102
103 state++;
104 if ((rlen = readv(fd, iv, 2)) > 0) {
105 fprintf(stderr, "Tunnel %d read %ld bytes\n",
106 fdkey, (long)(rlen - sizeof(type)));
107 tpkt.len = rlen - sizeof(type);
108
109 /* add write event on opposite tunnel */
110 event_add(&tunwev[oppfdkey], &exittv);
111 } else
112 errx(1, "Read from tunnel %d failed", fdkey);
113 }
114
115 void
tunnel_ping(int fd,short which,void * arg)116 tunnel_ping(int fd, short which, void *arg)
117 {
118 system("ping -c 1 -I " TUN0_ADDR " " TUN1_ADDR " >/dev/null &");
119 }
120
121 /*
122 * +------------+ +------------+
123 * | TUN0 | | TUN1 |
124 * | TUN0_ADDR | | TUN1_ADDR |
125 * +------------+ +------------+
126 *
127 * Set up both tunnel devices (TUN0, TUN1)
128 * This works because the routing table prefers the opposing end of the ptp
129 * interfaces.
130 * Set up one read and one write event per tunnel.
131 * The read events add the write event.
132 */
133 int
do_tun(void)134 do_tun(void)
135 {
136 struct event tunrev[2];
137 struct event pingev;
138 struct timeval pingtv = {TUN_PINGDEL, 0};
139
140 /* read buffer */
141 tpkt.buf = (u_char *)&pktbuf;
142 tpkt.len = 0;
143 tpkt.a = sizeof(pktbuf);
144
145 event_init();
146
147 /* tun0 */
148 if ((tunfd[0] = open("/dev/" TUN0, O_RDWR)) < 0)
149 errx(1, "Cannot open /dev/" TUN0);
150 event_set(&tunrev[0], tunfd[0], EV_READ, tunnel_read, NULL);
151 event_set(&tunwev[0], tunfd[0], EV_WRITE, tunnel_write, NULL);
152 event_add(&tunrev[0], &exittv);
153
154 /* tun1 */
155 if ((tunfd[1] = open("/dev/" TUN1, O_RDWR)) < 0)
156 errx(1, "Cannot open /dev/" TUN1);
157 event_set(&tunrev[1], tunfd[1], EV_READ, tunnel_read, NULL);
158 event_set(&tunwev[1], tunfd[1], EV_WRITE, tunnel_write, NULL);
159 event_add(&tunrev[1], &exittv);
160
161 /* ping */
162 evtimer_set(&pingev, tunnel_ping, NULL);
163 event_add(&pingev, &pingtv);
164
165 /* configure the interfaces */
166 system("ifconfig " TUN0 " " TUN0_ADDR
167 " netmask 255.255.255.255 " TUN1_ADDR);
168 system("ifconfig " TUN1 " " TUN1_ADDR
169 " netmask 255.255.255.255 " TUN0_ADDR);
170
171 state = 0;
172 if (event_dispatch() < 0)
173 errx(errno, "Event handler failed");
174
175 return (state != 4);
176 }
177