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1 | /* -*-c-*- |
2 | * |
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3 | * $Id$ |
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4 | * |
5 | * Tunnel interface based on Linux TUN/TAP driver |
6 | * |
7 | * (c) 2003 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 | |
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31 | #define TUN_INTERNALS |
32 | |
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33 | #include "tripe.h" |
34 | |
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35 | #ifdef TUN_LINUX |
36 | # include <sys/ioctl.h> |
37 | # include <linux/if.h> |
38 | # include <linux/if_tun.h> |
39 | #endif |
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40 | |
41 | /*----- Main code ---------------------------------------------------------*/ |
42 | |
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43 | #ifdef TUN_LINUX |
44 | |
45 | struct tunnel { |
46 | const tunnel_ops *ops; /* Pointer to operations */ |
47 | sel_file f; /* Selector for TUN/TAP device */ |
48 | struct peer *p; /* Pointer to my peer */ |
49 | char ifn[IFNAMSIZ]; /* Interface name buffer */ |
50 | }; |
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51 | |
52 | /* --- @t_read@ --- * |
53 | * |
54 | * Arguments: @int fd@ = file descriptor to read |
55 | * @unsigned mode@ = what's happened |
56 | * @void *v@ = pointer to tunnel block |
57 | * |
58 | * Returns: --- |
59 | * |
60 | * Use: Reads data from the tunnel. |
61 | */ |
62 | |
63 | static void t_read(int fd, unsigned mode, void *v) |
64 | { |
65 | tunnel *t = v; |
66 | ssize_t n; |
67 | buf b; |
68 | |
69 | n = read(fd, buf_i, sizeof(buf_i)); |
70 | if (n < 0) { |
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71 | a_warn("TUN %s read-error -- %s", t->ifn, strerror(errno)); |
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72 | return; |
73 | } |
74 | IF_TRACING(T_TUNNEL, { |
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75 | trace(T_TUNNEL, "tun-linux: packet arrived"); |
76 | trace_block(T_PACKET, "tun-linux: packet contents", buf_i, n); |
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77 | }) |
78 | buf_init(&b, buf_i, n); |
79 | p_tun(t->p, &b); |
80 | } |
81 | |
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82 | /* --- @t_init@ --- * |
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83 | * |
84 | * Arguments: --- |
85 | * |
86 | * Returns: --- |
87 | * |
88 | * Use: Initializes the tunneling system. Maybe this will require |
89 | * opening file descriptors or something. |
90 | */ |
91 | |
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92 | static void t_init(void) { return; } |
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93 | |
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94 | /* --- @t_create@ --- * |
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95 | * |
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96 | * Arguments: @peer *p@ = pointer to peer block |
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97 | * |
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98 | * Returns: A tunnel block if it worked, or null on failure. |
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99 | * |
100 | * Use: Initializes a new tunnel. |
101 | */ |
102 | |
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103 | static tunnel *t_create(peer *p) |
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104 | { |
105 | int fd; |
106 | int f; |
107 | struct ifreq iff; |
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108 | tunnel *t; |
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109 | |
110 | if ((fd = open("/dev/net/tun", O_RDWR)) < 0) { |
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111 | a_warn("TUN - open-error /dev/net/tun -- %s", strerror(errno)); |
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112 | return (0); |
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113 | } |
114 | fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC); |
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115 | memset(&iff, 0, sizeof(iff)); |
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116 | iff.ifr_name[0] = 0; |
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117 | iff.ifr_flags = IFF_TUN | IFF_NO_PI; |
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118 | if ((f = ioctl(fd, TUNSETIFF, &iff)) < 0) { |
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119 | a_warn("TUN - linux config-error -- %s", strerror(errno)); |
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120 | close(fd); |
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121 | return (0); |
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122 | } |
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123 | t = CREATE(tunnel); |
124 | t->ops = &tun_linux; |
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125 | t->p = p; |
126 | sel_initfile(&sel, &t->f, fd, SEL_READ, t_read, t); |
127 | sel_addfile(&t->f); |
128 | iff.ifr_name[IFNAMSIZ - 1] = 0; |
129 | strcpy(t->ifn, iff.ifr_name); |
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130 | T( trace(T_TUNNEL, "tun-linux: attached interface %s to peer `%s'", |
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131 | t->ifn, p_name(p)); ) |
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132 | return (t); |
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133 | } |
134 | |
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135 | /* --- @t_ifname@ --- * |
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136 | * |
137 | * Arguments: @tunnel *t@ = pointer to tunnel block |
138 | * |
139 | * Returns: A pointer to the tunnel's interface name. |
140 | */ |
141 | |
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142 | static const char *t_ifname(tunnel *t) { return (t->ifn); } |
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143 | |
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144 | /* --- @t_inject@ --- * |
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145 | * |
146 | * Arguments: @tunnel *t@ = pointer to tunnel block |
147 | * @buf *b@ = buffer to send |
148 | * |
149 | * Returns: --- |
150 | * |
151 | * Use: Injects a packet into the local network stack. |
152 | */ |
153 | |
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154 | static void t_inject(tunnel *t, buf *b) |
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155 | { |
156 | IF_TRACING(T_TUNNEL, { |
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157 | trace(T_TUNNEL, "tun-linux: inject decrypted packet"); |
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158 | trace_block(T_PACKET, "tunnel: packet contents", BBASE(b), BLEN(b)); |
159 | }) |
160 | write(t->f.fd, BBASE(b), BLEN(b)); |
161 | } |
162 | |
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163 | /* --- @t_destroy@ --- * |
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164 | * |
165 | * Arguments: @tunnel *t@ = pointer to tunnel block |
166 | * |
167 | * Returns: --- |
168 | * |
169 | * Use: Destroys a tunnel. |
170 | */ |
171 | |
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172 | static void t_destroy(tunnel *t) |
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173 | { |
174 | sel_rmfile(&t->f); |
175 | close(t->f.fd); |
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176 | DESTROY(t); |
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177 | } |
178 | |
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179 | const tunnel_ops tun_linux = { |
180 | "linux", |
181 | t_init, |
182 | t_create, |
183 | t_ifname, |
184 | t_inject, |
185 | t_destroy |
186 | }; |
187 | |
188 | #endif |
189 | |
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190 | /*----- That's all, folks -------------------------------------------------*/ |