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b96a6af6 | 1 | /* |
2 | * Copyright (c) 2005 Reyk Floeter <reyk@openbsd.org> | |
3 | * | |
4 | * Permission to use, copy, modify, and distribute this software for any | |
5 | * purpose with or without fee is hereby granted, provided that the above | |
6 | * copyright notice and this permission notice appear in all copies. | |
7 | * | |
8 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES | |
9 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF | |
10 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR | |
11 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES | |
12 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN | |
13 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF | |
14 | * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. | |
15 | */ | |
16 | ||
17 | #include "includes.h" | |
18 | ||
19 | #include "log.h" | |
20 | #include "misc.h" | |
21 | #include "bufaux.h" | |
22 | ||
23 | /* | |
24 | * This is the portable version of the SSH tunnel forwarding, it | |
25 | * uses some preprocessor definitions for various platform-specific | |
26 | * settings. | |
27 | * | |
28 | * SSH_TUN_LINUX Use the (newer) Linux tun/tap device | |
29 | * SSH_TUN_COMPAT_AF Translate the OpenBSD address family | |
30 | * SSH_TUN_PREPEND_AF Prepend/remove the address family | |
31 | */ | |
32 | ||
33 | /* | |
34 | * System-specific tunnel open function | |
35 | */ | |
36 | ||
37 | #if defined(SSH_TUN_LINUX) | |
38 | #include <linux/if.h> | |
39 | #include <linux/if_tun.h> | |
40 | ||
41 | int | |
42 | sys_tun_open(int tun, int mode) | |
43 | { | |
44 | struct ifreq ifr; | |
45 | int fd = -1; | |
46 | const char *name = NULL; | |
47 | ||
48 | if ((fd = open("/dev/net/tun", O_RDWR)) == -1) { | |
49 | debug("%s: failed to open tunnel control interface: %s", | |
50 | __func__, strerror(errno)); | |
51 | return (-1); | |
52 | } | |
53 | ||
54 | bzero(&ifr, sizeof(ifr)); | |
55 | ||
56 | if (mode == SSH_TUNMODE_ETHERNET) { | |
57 | ifr.ifr_flags = IFF_TAP; | |
58 | name = "tap%d"; | |
59 | } else { | |
60 | ifr.ifr_flags = IFF_TUN; | |
61 | name = "tun%d"; | |
62 | } | |
63 | ifr.ifr_flags |= IFF_NO_PI; | |
64 | ||
65 | if (tun != SSH_TUNID_ANY) { | |
66 | if (tun > SSH_TUNID_MAX) { | |
67 | debug("%s: invalid tunnel id %x: %s", __func__, | |
68 | tun, strerror(errno)); | |
69 | goto failed; | |
70 | } | |
71 | snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), name, tun); | |
72 | } | |
73 | ||
74 | if (ioctl(fd, TUNSETIFF, &ifr) == -1) { | |
75 | debug("%s: failed to configure tunnel (mode %d): %s", __func__, | |
76 | mode, strerror(errno)); | |
77 | goto failed; | |
78 | } | |
79 | ||
80 | if (tun == SSH_TUNID_ANY) | |
81 | debug("%s: tunnel mode %d fd %d", __func__, mode, fd); | |
82 | else | |
83 | debug("%s: %s mode %d fd %d", __func__, ifr.ifr_name, mode, fd); | |
84 | ||
85 | return (fd); | |
86 | ||
87 | failed: | |
88 | close(fd); | |
89 | return (-1); | |
90 | } | |
91 | #endif /* SSH_TUN_LINUX */ | |
92 | ||
93 | #ifdef SSH_TUN_FREEBSD | |
94 | #include <sys/socket.h> | |
95 | #include <net/if.h> | |
96 | #include <net/if_tun.h> | |
97 | ||
98 | int | |
99 | sys_tun_open(int tun, int mode) | |
100 | { | |
101 | struct ifreq ifr; | |
102 | char name[100]; | |
103 | int fd = -1, sock, flag; | |
104 | const char *tunbase = "tun"; | |
105 | ||
106 | if (mode == SSH_TUNMODE_ETHERNET) { | |
107 | #ifdef SSH_TUN_NO_L2 | |
108 | debug("%s: no layer 2 tunnelling support", __func__); | |
109 | return (-1); | |
110 | #else | |
111 | tunbase = "tap"; | |
112 | #endif | |
113 | } | |
114 | ||
115 | /* Open the tunnel device */ | |
116 | if (tun <= SSH_TUNID_MAX) { | |
117 | snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun); | |
118 | fd = open(name, O_RDWR); | |
119 | } else if (tun == SSH_TUNID_ANY) { | |
120 | for (tun = 100; tun >= 0; tun--) { | |
121 | snprintf(name, sizeof(name), "/dev/%s%d", | |
122 | tunbase, tun); | |
123 | if ((fd = open(name, O_RDWR)) >= 0) | |
124 | break; | |
125 | } | |
126 | } else { | |
127 | debug("%s: invalid tunnel %u\n", __func__, tun); | |
128 | return (-1); | |
129 | } | |
130 | ||
131 | if (fd < 0) { | |
132 | debug("%s: %s open failed: %s", __func__, name, | |
133 | strerror(errno)); | |
134 | return (-1); | |
135 | } | |
136 | ||
137 | /* Turn on tunnel headers */ | |
138 | flag = 1; | |
139 | #if defined(TUNSIFHEAD) && !defined(SSH_TUN_PREPEND_AF) | |
140 | if (mode != SSH_TUNMODE_ETHERNET && | |
141 | ioctl(fd, TUNSIFHEAD, &flag) == -1) { | |
142 | debug("%s: ioctl(%d, TUNSIFHEAD, 1): %s", __func__, fd, | |
143 | strerror(errno)); | |
144 | close(fd); | |
145 | } | |
146 | #endif | |
147 | ||
148 | debug("%s: %s mode %d fd %d", __func__, name, mode, fd); | |
149 | ||
150 | /* Set the tunnel device operation mode */ | |
151 | snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun); | |
152 | if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1) | |
153 | goto failed; | |
154 | ||
155 | if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1) | |
156 | goto failed; | |
157 | ifr.ifr_flags |= IFF_UP; | |
158 | if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1) | |
159 | goto failed; | |
160 | ||
161 | close(sock); | |
162 | return (fd); | |
163 | ||
164 | failed: | |
165 | if (fd >= 0) | |
166 | close(fd); | |
167 | if (sock >= 0) | |
168 | close(sock); | |
169 | debug("%s: failed to set %s mode %d: %s", __func__, name, | |
170 | mode, strerror(errno)); | |
171 | return (-1); | |
172 | } | |
173 | #endif /* SSH_TUN_FREEBSD */ | |
174 | ||
175 | /* | |
176 | * System-specific channel filters | |
177 | */ | |
178 | ||
179 | #if defined(SSH_TUN_FILTER) | |
180 | #define OPENBSD_AF_INET 2 | |
181 | #define OPENBSD_AF_INET6 24 | |
182 | ||
183 | int | |
184 | sys_tun_infilter(struct Channel *c, char *buf, int len) | |
185 | { | |
186 | #if defined(SSH_TUN_PREPEND_AF) | |
187 | char rbuf[CHAN_RBUF]; | |
188 | struct ip *iph; | |
189 | #endif | |
190 | u_int32_t *af; | |
191 | char *ptr = buf; | |
192 | ||
193 | #if defined(SSH_TUN_PREPEND_AF) | |
194 | if (len <= 0 || len > (int)(sizeof(rbuf) - sizeof(*af))) | |
195 | return (-1); | |
196 | ptr = (char *)&rbuf[0]; | |
197 | bcopy(buf, ptr + sizeof(u_int32_t), len); | |
198 | len += sizeof(u_int32_t); | |
199 | af = (u_int32_t *)ptr; | |
200 | ||
201 | iph = (struct ip *)(ptr + sizeof(u_int32_t)); | |
202 | switch (iph->ip_v) { | |
203 | case 6: | |
204 | *af = AF_INET6; | |
205 | break; | |
206 | case 4: | |
207 | default: | |
208 | *af = AF_INET; | |
209 | break; | |
210 | } | |
211 | #endif | |
212 | ||
213 | #if defined(SSH_TUN_COMPAT_AF) | |
214 | if (len < (int)sizeof(u_int32_t)) | |
215 | return (-1); | |
216 | ||
217 | af = (u_int32_t *)ptr; | |
218 | if (*af == htonl(AF_INET6)) | |
219 | *af = htonl(OPENBSD_AF_INET6); | |
220 | else | |
221 | *af = htonl(OPENBSD_AF_INET); | |
222 | #endif | |
223 | ||
224 | buffer_put_string(&c->input, ptr, len); | |
225 | return (0); | |
226 | } | |
227 | ||
228 | u_char * | |
229 | sys_tun_outfilter(struct Channel *c, u_char **data, u_int *dlen) | |
230 | { | |
231 | u_char *buf; | |
232 | u_int32_t *af; | |
233 | ||
234 | *data = buffer_get_string(&c->output, dlen); | |
235 | if (*dlen < sizeof(*af)) | |
236 | return (NULL); | |
237 | buf = *data; | |
238 | ||
239 | #if defined(SSH_TUN_PREPEND_AF) | |
240 | *dlen -= sizeof(u_int32_t); | |
241 | buf = *data + sizeof(u_int32_t); | |
242 | #elif defined(SSH_TUN_COMPAT_AF) | |
243 | af = ntohl(*(u_int32_t *)buf); | |
244 | if (*af == OPENBSD_AF_INET6) | |
245 | *af = htonl(AF_INET6); | |
246 | else | |
247 | *af = htonl(AF_INET); | |
248 | #endif | |
249 | ||
250 | return (buf); | |
251 | } | |
252 | #endif /* SSH_TUN_FILTER */ |