| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id$ |
| 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 | |
| 29 | /*----- Header files ------------------------------------------------------*/ |
| 30 | |
| 31 | #define TUN_INTERNALS |
| 32 | |
| 33 | #include "tripe.h" |
| 34 | |
| 35 | #ifdef TUN_LINUX |
| 36 | # include <sys/ioctl.h> |
| 37 | # include <linux/if.h> |
| 38 | # include <linux/if_tun.h> |
| 39 | #endif |
| 40 | |
| 41 | /*----- Main code ---------------------------------------------------------*/ |
| 42 | |
| 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 | }; |
| 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) { |
| 71 | a_warn("TUN", "%s", t->ifn, "read-error", "?ERRNO", A_END); |
| 72 | return; |
| 73 | } |
| 74 | IF_TRACING(T_TUNNEL, { |
| 75 | trace(T_TUNNEL, "tun-linux: packet arrived"); |
| 76 | trace_block(T_PACKET, "tun-linux: packet contents", buf_i, n); |
| 77 | }) |
| 78 | buf_init(&b, buf_i, n); |
| 79 | p_tun(t->p, &b); |
| 80 | } |
| 81 | |
| 82 | /* --- @t_init@ --- * |
| 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 | |
| 92 | static void t_init(void) { return; } |
| 93 | |
| 94 | /* --- @t_create@ --- * |
| 95 | * |
| 96 | * Arguments: @peer *p@ = pointer to peer block |
| 97 | * |
| 98 | * Returns: A tunnel block if it worked, or null on failure. |
| 99 | * |
| 100 | * Use: Initializes a new tunnel. |
| 101 | */ |
| 102 | |
| 103 | static tunnel *t_create(peer *p) |
| 104 | { |
| 105 | int fd; |
| 106 | int f; |
| 107 | struct ifreq iff; |
| 108 | tunnel *t; |
| 109 | |
| 110 | if ((fd = open("/dev/net/tun", O_RDWR)) < 0) { |
| 111 | a_warn("TUN", "-", "linux", |
| 112 | "open-error", "/dev/net/tun", "?ERRNO", |
| 113 | A_END); |
| 114 | return (0); |
| 115 | } |
| 116 | fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC); |
| 117 | memset(&iff, 0, sizeof(iff)); |
| 118 | iff.ifr_name[0] = 0; |
| 119 | iff.ifr_flags = IFF_TUN | IFF_NO_PI; |
| 120 | if ((f = ioctl(fd, TUNSETIFF, &iff)) < 0) { |
| 121 | a_warn("TUN", "-", "linux", "config-error", "?ERRNO", A_END); |
| 122 | close(fd); |
| 123 | return (0); |
| 124 | } |
| 125 | t = CREATE(tunnel); |
| 126 | t->ops = &tun_linux; |
| 127 | t->p = p; |
| 128 | sel_initfile(&sel, &t->f, fd, SEL_READ, t_read, t); |
| 129 | sel_addfile(&t->f); |
| 130 | iff.ifr_name[IFNAMSIZ - 1] = 0; |
| 131 | strcpy(t->ifn, iff.ifr_name); |
| 132 | T( trace(T_TUNNEL, "tun-linux: attached interface %s to peer `%s'", |
| 133 | t->ifn, p_name(p)); ) |
| 134 | return (t); |
| 135 | } |
| 136 | |
| 137 | /* --- @t_ifname@ --- * |
| 138 | * |
| 139 | * Arguments: @tunnel *t@ = pointer to tunnel block |
| 140 | * |
| 141 | * Returns: A pointer to the tunnel's interface name. |
| 142 | */ |
| 143 | |
| 144 | static const char *t_ifname(tunnel *t) { return (t->ifn); } |
| 145 | |
| 146 | /* --- @t_inject@ --- * |
| 147 | * |
| 148 | * Arguments: @tunnel *t@ = pointer to tunnel block |
| 149 | * @buf *b@ = buffer to send |
| 150 | * |
| 151 | * Returns: --- |
| 152 | * |
| 153 | * Use: Injects a packet into the local network stack. |
| 154 | */ |
| 155 | |
| 156 | static void t_inject(tunnel *t, buf *b) |
| 157 | { |
| 158 | IF_TRACING(T_TUNNEL, { |
| 159 | trace(T_TUNNEL, "tun-linux: inject decrypted packet"); |
| 160 | trace_block(T_PACKET, "tunnel: packet contents", BBASE(b), BLEN(b)); |
| 161 | }) |
| 162 | write(t->f.fd, BBASE(b), BLEN(b)); |
| 163 | } |
| 164 | |
| 165 | /* --- @t_destroy@ --- * |
| 166 | * |
| 167 | * Arguments: @tunnel *t@ = pointer to tunnel block |
| 168 | * |
| 169 | * Returns: --- |
| 170 | * |
| 171 | * Use: Destroys a tunnel. |
| 172 | */ |
| 173 | |
| 174 | static void t_destroy(tunnel *t) |
| 175 | { |
| 176 | sel_rmfile(&t->f); |
| 177 | close(t->f.fd); |
| 178 | DESTROY(t); |
| 179 | } |
| 180 | |
| 181 | const tunnel_ops tun_linux = { |
| 182 | "linux", |
| 183 | t_init, |
| 184 | t_create, |
| 185 | t_ifname, |
| 186 | t_inject, |
| 187 | t_destroy |
| 188 | }; |
| 189 | |
| 190 | #endif |
| 191 | |
| 192 | /*----- That's all, folks -------------------------------------------------*/ |