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