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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: tun-bsd.c,v 1.3 2004/04/08 01:36:17 mdw Exp $ |
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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 | |
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29 | /*----- Header files ------------------------------------------------------*/ |
30 | |
31 | #include "tripe.h" |
32 | |
33 | /*----- Main code ---------------------------------------------------------*/ |
34 | |
35 | #if TUN_TYPE != TUN_BSD |
36 | # error "Tunnel type mismatch: fix the Makefile" |
37 | #endif |
38 | |
39 | /* --- @t_read@ --- * |
40 | * |
41 | * Arguments: @int fd@ = file descriptor to read |
42 | * @unsigned mode@ = what's happened |
43 | * @void *v@ = pointer to tunnel block |
44 | * |
45 | * Returns: --- |
46 | * |
47 | * Use: Reads data from the tunnel. |
48 | */ |
49 | |
50 | void t_read(int fd, unsigned mode, void *v) |
51 | { |
52 | tunnel *t = v; |
53 | ssize_t n; |
54 | buf b; |
55 | |
56 | n = read(fd, buf_i, sizeof(buf_i)); |
57 | if (n < 0) { |
58 | a_warn("tunnel read failed (%s): %s", tun_ifname(t), strerror(errno)); |
59 | return; |
60 | } |
61 | IF_TRACING(T_TUNNEL, { |
62 | trace(T_TUNNEL, "tunnel: packet arrived"); |
63 | trace_block(T_PACKET, "tunnel: packet contents", buf_i, n); |
64 | }) |
65 | buf_init(&b, buf_i, n); |
66 | p_tun(t->p, &b); |
67 | } |
68 | |
69 | /* --- @tun_init@ --- * |
70 | * |
71 | * Arguments: --- |
72 | * |
73 | * Returns: --- |
74 | * |
75 | * Use: Initializes the tunneling system. Maybe this will require |
76 | * opening file descriptors or something. |
77 | */ |
78 | |
79 | void tun_init(void) |
80 | { |
81 | return; |
82 | } |
83 | |
84 | /* --- @tun_create@ --- * |
85 | * |
86 | * Arguments: @tunnel *t@ = pointer to tunnel block |
87 | * @peer *p@ = pointer to peer block |
88 | * |
89 | * Returns: Zero if it worked, nonzero on failure. |
90 | * |
91 | * Use: Initializes a new tunnel. |
92 | */ |
93 | |
94 | int tun_create(tunnel *t, peer *p) |
95 | { |
96 | int fd; |
97 | unsigned n; |
98 | char buf[16]; |
99 | |
100 | n = 0; |
101 | for (;;) { |
102 | sprintf(buf, "/dev/tun%u", n); |
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103 | if ((fd = open(buf, O_RDWR)) >= 0) |
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104 | break; |
105 | switch (errno) { |
106 | case EBUSY: |
107 | T( trace(T_TUNNEL, "tunnel device %u busy: skipping", n); ) |
108 | break; |
109 | case ENOENT: |
110 | a_warn("no suitable tunnel devices found"); |
111 | return (-1); |
112 | default: |
113 | a_warn("error opening `%s': %s (skipping)", buf, strerror(errno)); |
114 | break; |
115 | } |
116 | n++; |
117 | } |
118 | |
119 | fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC); |
120 | t->p = p; |
121 | t->n = n; |
122 | sel_initfile(&sel, &t->f, fd, SEL_READ, t_read, t); |
123 | sel_addfile(&t->f); |
124 | T( trace(T_TUNNEL, "tunnel: attached interface %s to peer `%s'", |
125 | tun_ifname(t), p_name(p)); ) |
126 | return (0); |
127 | } |
128 | |
129 | /* --- @tun_ifname@ --- * |
130 | * |
131 | * Arguments: @tunnel *t@ = pointer to tunnel block |
132 | * |
133 | * Returns: A pointer to the tunnel's interface name. |
134 | */ |
135 | |
136 | const char *tun_ifname(tunnel *t) |
137 | { |
138 | static char buf[8]; |
139 | sprintf(buf, "tun%u", t->n); |
140 | return (buf); |
141 | } |
142 | |
143 | /* --- @tun_inject@ --- * |
144 | * |
145 | * Arguments: @tunnel *t@ = pointer to tunnel block |
146 | * @buf *b@ = buffer to send |
147 | * |
148 | * Returns: --- |
149 | * |
150 | * Use: Injects a packet into the local network stack. |
151 | */ |
152 | |
153 | void tun_inject(tunnel *t, buf *b) |
154 | { |
155 | IF_TRACING(T_TUNNEL, { |
156 | trace(T_TUNNEL, "tunnel: inject decrypted packet"); |
157 | trace_block(T_PACKET, "tunnel: packet contents", BBASE(b), BLEN(b)); |
158 | }) |
159 | write(t->f.fd, BBASE(b), BLEN(b)); |
160 | } |
161 | |
162 | /* --- @tun_destroy@ --- * |
163 | * |
164 | * Arguments: @tunnel *t@ = pointer to tunnel block |
165 | * |
166 | * Returns: --- |
167 | * |
168 | * Use: Destroys a tunnel. |
169 | */ |
170 | |
171 | void tun_destroy(tunnel *t) |
172 | { |
173 | sel_rmfile(&t->f); |
174 | close(t->f.fd); |
175 | } |
176 | |
177 | /*----- That's all, folks -------------------------------------------------*/ |