2 * Encrypting tunnel for userv-ipif tunnels, actual core implementation
6 * udptunnel-forwarder <optchars>
7 * <public-local-fd> <private-in-fd> <private-out-fd>
9 * <mtu> <keepalive> <timeout> <reannounce>
10 * <public-remote-addr> [<public-remote-port>]
11 * |<mech1> [<mech1-params> ...]
12 * |<mech2> [<mech2-params> ...]
15 * Remote addr may '' to mean wait to receive a packet and reply to
16 * whereever we get a good packet from first, in which case port
17 * should not be specified.
19 * <optchars> is zero or more of
20 * w means generate and write encdec keys, rather than reading them
21 * K means do crypto debug (use with care!)
23 * encdec keys datastream has keys for packets from key datastream
24 * writer to reader first, then keys for packets from reader to
27 * Every addr or port must be numeric. There is very little argument checking.
31 * 0 terminated due to outbound packet stream EOF
38 * Copyright (C) 2000,2003 Ian Jackson
39 * This file is part of ipif, part of userv-utils
41 * This is free software; you can redistribute it and/or modify it
42 * under the terms of the GNU General Public License as published by
43 * the Free Software Foundation; either version 2 of the License, or
44 * (at your option) any later version.
46 * This program is distributed in the hope that it will be useful, but
47 * WITHOUT ANY WARRANTY; without even the implied warranty of
48 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
49 * General Public License for more details.
51 * You should have received a copy of the GNU General Public License
52 * along with userv-utils; if not, write to the Free Software
53 * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
56 #include <sys/socket.h>
57 #include <netinet/in.h>
58 #include <arpa/inet.h>
59 #include <sys/utsname.h>
70 #include "forwarder.h"
74 static size_t buffer_size
;
75 static struct utsname uname_result
;
77 static const char *opt_chars
;
78 static int public_local_fd
, private_in_fd
, private_out_fd
;
79 static int mtu2
, keepalive
, timeout
, reannounce
;
80 static int public_remote_specd
;
81 static struct sockaddr_in public_remote
;
82 static int encdec_keys_fd
, encdec_keys_write
, crypto_debug
;
84 static const struct mechanism
*mechs
[MAXMECHS
];
86 static struct mechdata
*md_in
[MAXMECHS
], *md_out
[MAXMECHS
];
87 static int maxprefix
, maxsuffix
;
89 static struct buffer buf_in
, buf_out
;
90 static unsigned char *accum_buf
;
91 static size_t accum_used
, accum_avail
;
93 static time_t nextsendka
;
95 static void cdebug(int mechno
/*or -1*/, const char *msg
) {
96 if (!crypto_debug
) return;
97 printf("%-8.8s: CRYPTO: %-20s %s\n",
98 uname_result
.nodename
,
99 mechno
>= 0 ? mechs
[mechno
]->name
: "",
103 static void cdebughex(int mechno
/*or -1*/, const char *msg
, const void *ptr
,
104 size_t sz
, size_t skipbefore
,
105 int spc_offset
, int dot_offset
) {
106 const unsigned char *p
;
108 unsigned j
= dot_offset
;
110 if (!crypto_debug
) return;
111 printf("%-8.8s: CRYPTO: %-20s %-10s",
112 uname_result
.nodename
,
113 mechno
>= 0 ? mechs
[mechno
]->name
: "",
116 for (i
=0; i
<spc_offset
; i
++, j
++) fputs(j
&3 ?
" " : " ",stdout
);
117 for (i
=0; i
<skipbefore
; i
++, j
++) fputs(j
&3 ?
".." : " ..",stdout
);
118 for (i
=0, p
=ptr
; i
<sz
; i
++, j
++, p
++) printf(j
&3 ?
"%02x" : " %02x",*p
);
123 static void cdebugbuf(int mechno
/*or -1*/, const char *msg
,
124 const struct buffer
*buf
, int spc_offset
, int dot_offset
) {
125 cdebughex(mechno
, msg
, buf
->start
, buf
->size
, buf
->start
- buf
->base
,
126 spc_offset
, dot_offset
);
129 void get_random(void *ptr
, size_t sz
) {
130 static FILE *randfile
;
135 randfile
= fopen("/dev/urandom","rb");
136 if (!randfile
&& errno
==ENOENT
) randfile
= fopen("/dev/random","rb");
137 if (!randfile
) sysfail("open random number generator");
140 r
= fread(ptr
,1,sz
,randfile
);
142 (ferror(randfile
) ? sysfail
: fail
)("cannot read random number generator");
144 cdebughex(-1, "get_random", ptr
, sz
, 0,0,0);
147 void random_key(void *ptr
, size_t sz
) {
148 if (encdec_keys_write
) {
150 write_must(encdec_keys_fd
,ptr
,sz
,"write keys datastream");
152 read_must(encdec_keys_fd
,ptr
,sz
,"read keys datastream");
153 cdebughex(-1, "random_key", ptr
, sz
, 0,0,0);
158 static void setnonblock(int fd
, int nonblock
) {
161 r
= fcntl(fd
,F_GETFL
);
162 if (r
==-1) sysfail("fcntl F_GETFL");
163 r
= fcntl(fd
,F_SETFL
, nonblock ? r
|O_NONBLOCK
: r
&~O_NONBLOCK
);
164 if (r
==-1) sysfail("fcntl F_SETFL");
167 static const struct mechanism
*find_mech(const char *name
) {
168 const struct mechanism
*mech
, *const *mechlist
;
170 for (mechlist
= mechanismlists
;
173 for (mech
= *mechlist
; mech
->name
; mech
++)
174 if (!strcmp(mech
->name
,name
)) return mech
;
176 fprintf(stderr
,"%s: unknown mechanism: %s\n",programid
,name
);
180 static void inbound(void) {
181 static int any_recvd
;
182 static time_t nextreann
;
183 static unsigned long npackets
, nbytes
;
185 struct sockaddr_in this_saddr
;
186 size_t this_saddrlen
;
190 buf_in
.start
= buf_in
.base
+1;
191 buf_in
.size
= buffer_size
-2;
193 setnonblock(public_local_fd
,1);
194 this_saddrlen
= sizeof(this_saddr
);
195 r
= recvfrom(public_local_fd
, buf_in
.start
, buf_in
.size
, 0,
196 &this_saddr
, &this_saddrlen
);
197 if (!r
) { diag("empty ciphertext"); return; }
200 if (errno
!= EAGAIN
&& errno
!= EINTR
) { sysdiag("receive"); sleep(1); }
203 if (this_saddr
.sin_family
!= AF_INET
) {
204 fprintf(stderr
,"%s: received unknown AF %lu\n",
205 programid
, (unsigned long)this_saddr
.sin_family
);
208 assert(this_saddrlen
== sizeof(this_saddr
));
210 assert(r
<= buf_in
.size
);
212 cdebugbuf(-1, "decode", &buf_in
, 3,0);
213 for (i
=n_mechs
-1; i
>=0; i
--) {
214 emsg
= mechs
[i
]->decode(md_in
[i
],&buf_in
);
217 fprintf(stderr
, "%s: bad packet: %s: %s\n",
218 programid
, mechs
[i
]->name
, emsg
);
220 cdebug(i
,"silently discarded");
223 cdebugbuf(i
, "decode", &buf_in
, 3,0);
227 nbytes
+= buf_in
.size
;
230 different
= (!public_remote_specd
||
231 public_remote
.sin_addr
.s_addr
!= this_saddr
.sin_addr
.s_addr
||
232 public_remote
.sin_port
!= this_saddr
.sin_port
);
236 if (public_remote_specd
==2) {
237 fprintf(stderr
, "%s: packet from unexpected sender %s:%lu\n",
238 programid
, inet_ntoa(this_saddr
.sin_addr
),
239 (unsigned long)ntohs(this_saddr
.sin_port
));
243 fprintf(stderr
, "%s: tunnel open with peer %s:%lu\n",
244 programid
, inet_ntoa(this_saddr
.sin_addr
),
245 (unsigned long)ntohs(this_saddr
.sin_port
));
247 public_remote_specd
= 1;
248 memcpy(&public_remote
,&this_saddr
,sizeof(public_remote
));
250 } else if (!any_recvd
) {
254 } else if (reannounce
&& now() >= nextreann
) {
256 fprintf(stderr
, "%s: tunnel still open: received %lu packets, %lu bytes\n",
257 programid
, npackets
, nbytes
);
261 goto no_set_reann
; /* only reset this if we don't print a message. */
266 nextreann
= now() + reannounce
;
272 if (!buf_in
.size
|| *buf_in
.start
!= 0300) {
273 *--buf_in
.start
= 0300;
276 if (buf_in
.start
[buf_in
.size
-1] != 0300) {
277 buf_in
.start
[buf_in
.size
++]= 0300;
280 setnonblock(private_in_fd
,0);
281 write_must(private_in_fd
, buf_in
.start
, buf_in
.size
, "write down");
284 static void sendpacket(const unsigned char *message
, size_t size
) {
287 buf_out
.start
= buf_out
.base
+maxprefix
;
289 memcpy(buf_out
.start
, message
, size
);
291 nextsendka
= now() + keepalive
;
293 cdebugbuf(-1, "encode", &buf_out
, 4,0);
294 for (i
=0; i
<n_mechs
; i
++) {
295 mechs
[i
]->encode(md_out
[i
],&buf_out
);
296 cdebugbuf(i
, "encode", &buf_out
, 4,0);
298 assert(public_remote_specd
);
300 setnonblock(public_local_fd
,1);
302 r
= sendto(public_local_fd
, buf_out
.start
, buf_out
.size
, 0,
303 &public_remote
, sizeof(public_remote
));
304 if (r
== buf_out
.size
) break;
305 if (r
>= 0) { diag("unexpected short send"); return; }
306 if (errno
!= EINTR
) { sysdiag("send"); return; }
310 static void outbound(void) {
312 unsigned char *after_eaten
, *delim
;
315 setnonblock(private_out_fd
,1);
318 r
= read(private_out_fd
, accum_buf
+ accum_used
, accum_avail
- accum_used
);
319 if (!r
) { diag("outbound datastream closed, quitting"); exit(0); }
321 if (errno
== EAGAIN
) return;
322 if (errno
== EINTR
) continue;
325 assert(accum_used
<=accum_avail
);
327 after_eaten
= accum_buf
;
328 while ((delim
= memchr(after_eaten
, 0300, accum_used
))) {
329 this_packet
= delim
- after_eaten
;
330 if (this_packet
) sendpacket(after_eaten
, this_packet
);
331 accum_used
-= this_packet
+1;
332 after_eaten
= delim
+1;
334 memmove(accum_buf
, after_eaten
, accum_used
);
336 if (accum_used
== accum_avail
) {
337 diag("missing interpacket delimiter in output datastream");
343 int main(int argc
, const char *const *const argv_in
) {
345 const char *const *argv_save
;
346 const char *const *argv_done
;
347 struct pollfd pollfds
[2];
348 int i
, polltimeout
, r
;
353 if (uname(&uname_result
)) { perror(PROGRAM
": uname failed"); exit(16); }
354 sprintf(programid
, PROGRAM
": %.*s", SYS_NMLN
, uname_result
.nodename
);
356 opt_chars
= getarg_string();
357 encdec_keys_write
= !!strchr(opt_chars
,'w');
358 crypto_debug
= !!strchr(opt_chars
,'K');
360 public_local_fd
= getarg_ulong();
361 private_in_fd
= getarg_ulong();
362 private_out_fd
= getarg_ulong();
363 encdec_keys_fd
= getarg_ulong();
365 mtu2
= getarg_ulong() * 2;
366 keepalive
= getarg_ulong();
367 timeout
= getarg_ulong();
368 reannounce
= getarg_ulong();
370 arg
= getarg_string();
372 public_remote_specd
= 1;
373 public_remote
.sin_family
= AF_INET
;
374 arg_assert(inet_aton(arg
,&public_remote
.sin_addr
));
375 public_remote
.sin_port
= htons(getarg_ulong());
379 diag("crypto debugging enabled!");
380 setvbuf(stdout
,0,_IOLBF
,0);
385 while ((arg
= *++argv
)) {
386 arg_assert(*arg
++ == '|');
387 arg_assert(i
<= MAXMECHS
);
388 mechs
[i
]= find_mech(arg
);
390 cdebug(i
,"writer->reader setup");
393 if (encdec_keys_write
)
394 mechs
[i
]->encsetup(&md_out
[i
], &maxprefix
, &maxsuffix
);
396 mechs
[i
]->decsetup(&md_in
[i
]);
400 cdebug(i
,"reader->writer setup");
402 if (encdec_keys_write
)
403 mechs
[i
]->decsetup(&md_in
[i
]);
405 mechs
[i
]->encsetup(&md_out
[i
], &maxprefix
, &maxsuffix
);
407 assert(argv
== argv_done
);
413 if (maxprefix
<1) maxprefix
= 1;
414 if (maxsuffix
<1) maxsuffix
= 1;
415 buffer_size
= mtu2
+ maxprefix
+ maxsuffix
;
416 buf_in
.base
= xmalloc(buffer_size
);
417 buf_out
.base
= xmalloc(buffer_size
);
418 accum_avail
= mtu2
+ 1;
419 accum_buf
= xmalloc(accum_avail
);
423 pollfds
[0].fd
= public_local_fd
;
424 pollfds
[0].events
= POLLIN
;
425 pollfds
[1].fd
= private_out_fd
;
427 pollfds
[1].events
= public_remote_specd ? POLLIN
: 0;
428 pollfds
[0].revents
= 0;
429 pollfds
[1].revents
= 0;
433 if (tnow
>= nextsendka
&& public_remote_specd
)
434 sendpacket((unsigned char*)"\300",1);
435 polltimeout
= (nextsendka
- tnow
)*1000;
440 r
= poll(pollfds
,2,polltimeout
);
442 if (r
==-1 && errno
==EINTR
) continue;
443 if (r
==-1) sysfail("poll");
445 if (pollfds
[0].revents
& (POLLIN
|POLLERR
)) inbound();
446 if (pollfds
[1].revents
& (POLLIN
|POLLERR
)) outbound();