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[tripe] / tun-bsd.c
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fd528bde 1/* -*-c-*-
2 *
3cdc3f3a 3 * $Id$
fd528bde 4 *
5 * Tunnel interface for 4.4BSD-derived systems
6 *
7 * (c) 2001 Straylight/Edgeware
8 */
9
10/*----- Licensing notice --------------------------------------------------*
11 *
12 * This file is part of Trivial IP Encryption (TrIPE).
13 *
14 * TrIPE is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
18 *
19 * TrIPE is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with TrIPE; if not, write to the Free Software Foundation,
26 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27 */
28
fd528bde 29/*----- Header files ------------------------------------------------------*/
30
42da2a58 31#define TUN_INTERNALS
32
fd528bde 33#include "tripe.h"
34
35/*----- Main code ---------------------------------------------------------*/
36
42da2a58 37#ifdef TUN_BSD
38
39struct tunnel {
40 const tunnel_ops *ops; /* Pointer to operations */
41 sel_file f; /* Selector for tunnel device */
42 struct peer *p; /* Pointer to my peer */
43 unsigned n; /* Number of my tunnel device */
44};
45
46/* --- @t_ifname@ --- *
47 *
48 * Arguments: @tunnel *t@ = pointer to tunnel block
49 *
50 * Returns: A pointer to the tunnel's interface name.
51 */
52
53static const char *t_ifname(tunnel *t)
54{
55 static char buf[8];
56 sprintf(buf, "tun%u", t->n);
57 return (buf);
58}
fd528bde 59
60/* --- @t_read@ --- *
61 *
62 * Arguments: @int fd@ = file descriptor to read
63 * @unsigned mode@ = what's happened
64 * @void *v@ = pointer to tunnel block
65 *
66 * Returns: ---
67 *
68 * Use: Reads data from the tunnel.
69 */
70
42da2a58 71static void t_read(int fd, unsigned mode, void *v)
fd528bde 72{
73 tunnel *t = v;
74 ssize_t n;
75 buf b;
76
77 n = read(fd, buf_i, sizeof(buf_i));
78 if (n < 0) {
f43df819 79 a_warn("TUN", "%s", t_ifname(t), "read-error", "?ERRNO", A_END);
fd528bde 80 return;
81 }
82 IF_TRACING(T_TUNNEL, {
060ca767 83 trace(T_TUNNEL, "tun-bsd: packet arrived");
84 trace_block(T_PACKET, "tun-bsd: packet contents", buf_i, n);
fd528bde 85 })
86 buf_init(&b, buf_i, n);
87 p_tun(t->p, &b);
88}
89
42da2a58 90/* --- @t_init@ --- *
fd528bde 91 *
92 * Arguments: ---
93 *
94 * Returns: ---
95 *
96 * Use: Initializes the tunneling system. Maybe this will require
97 * opening file descriptors or something.
98 */
99
42da2a58 100static void t_init(void) { return; }
fd528bde 101
42da2a58 102/* --- @t_create@ --- *
fd528bde 103 *
42da2a58 104 * Arguments: @peer *p@ = pointer to peer block
fd528bde 105 *
42da2a58 106 * Returns: A tunnel block if it worked, or null on failure.
fd528bde 107 *
108 * Use: Initializes a new tunnel.
109 */
110
42da2a58 111static tunnel *t_create(peer *p)
fd528bde 112{
113 int fd;
114 unsigned n;
42da2a58 115 tunnel *t;
fd528bde 116 char buf[16];
117
118 n = 0;
119 for (;;) {
120 sprintf(buf, "/dev/tun%u", n);
ef4a1ab7 121 if ((fd = open(buf, O_RDWR)) >= 0)
fd528bde 122 break;
123 switch (errno) {
124 case EBUSY:
125 T( trace(T_TUNNEL, "tunnel device %u busy: skipping", n); )
126 break;
127 case ENOENT:
f43df819 128 a_warn("TUN", "-", "bsd", "no-tunnel-devices", A_END);
42da2a58 129 return (0);
fd528bde 130 default:
f43df819 131 a_warn("TUN", "-", "open-error", "%s", buf, "?ERRNO", A_END);
fd528bde 132 break;
133 }
134 n++;
135 }
136
42da2a58 137 t = CREATE(tunnel);
138 t->ops = &tun_bsd;
fd528bde 139 fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
140 t->p = p;
141 t->n = n;
142 sel_initfile(&sel, &t->f, fd, SEL_READ, t_read, t);
143 sel_addfile(&t->f);
060ca767 144 T( trace(T_TUNNEL, "tun-bsd: attached interface %s to peer `%s'",
42da2a58 145 t_ifname(t), p_name(p)); )
146 return (t);
fd528bde 147}
148
42da2a58 149/* --- @t_inject@ --- *
fd528bde 150 *
151 * Arguments: @tunnel *t@ = pointer to tunnel block
152 * @buf *b@ = buffer to send
153 *
154 * Returns: ---
155 *
156 * Use: Injects a packet into the local network stack.
157 */
158
42da2a58 159static void t_inject(tunnel *t, buf *b)
fd528bde 160{
161 IF_TRACING(T_TUNNEL, {
060ca767 162 trace(T_TUNNEL, "tun-bsd: inject decrypted packet");
163 trace_block(T_PACKET, "tun-bsd: packet contents", BBASE(b), BLEN(b));
fd528bde 164 })
165 write(t->f.fd, BBASE(b), BLEN(b));
166}
167
42da2a58 168/* --- @t_destroy@ --- *
fd528bde 169 *
170 * Arguments: @tunnel *t@ = pointer to tunnel block
171 *
172 * Returns: ---
173 *
174 * Use: Destroys a tunnel.
175 */
176
42da2a58 177static void t_destroy(tunnel *t)
fd528bde 178{
179 sel_rmfile(&t->f);
180 close(t->f.fd);
42da2a58 181 DESTROY(t);
fd528bde 182}
183
42da2a58 184const tunnel_ops tun_bsd = {
185 "bsd",
186 t_init,
187 t_create,
188 t_ifname,
189 t_inject,
190 t_destroy
191};
192
193#endif
194
fd528bde 195/*----- That's all, folks -------------------------------------------------*/