1 /* site.c - manage communication with a remote network site */
3 /* The 'site' code doesn't know anything about the structure of the
4 packets it's transmitting. In fact, under the new netlink
5 configuration scheme it doesn't need to know anything at all about
6 IP addresses, except how to contact its peer. This means it could
7 potentially be used to tunnel other protocols too (IPv6, IPX, plain
8 old Ethernet frames) if appropriate netlink code can be written
9 (and that ought not to be too hard, eg. using the TUN/TAP device to
10 pretend to be an Ethernet interface). */
12 /* At some point in the future the netlink code will be asked for
13 configuration information to go in the PING/PONG packets at the end
14 of the key exchange. */
21 #include <sys/socket.h>
25 #include "unaligned.h"
28 #define SETUP_BUFFER_LEN 2048
30 #define DEFAULT_KEY_LIFETIME 3600000 /* One hour */
31 #define DEFAULT_KEY_RENEGOTIATE_GAP 300000 /* Five minutes */
32 #define DEFAULT_SETUP_RETRIES 5
33 #define DEFAULT_SETUP_TIMEOUT 2000
34 #define DEFAULT_WAIT_TIME 20000
36 /* Each site can be in one of several possible states. */
39 SITE_STOP - nothing is allowed to happen; tunnel is down;
40 all session keys have been erased
41 -> SITE_RUN upon external instruction
42 SITE_RUN - site up, maybe with valid key
43 -> SITE_RESOLVE upon outgoing packet and no valid key
44 we start name resolution for the other end of the tunnel
45 -> SITE_SENTMSG2 upon valid incoming message 1 and suitable time
46 we send an appropriate message 2
47 SITE_RESOLVE - waiting for name resolution
48 -> SITE_SENTMSG1 upon successful resolution
49 we send an appropriate message 1
50 -> SITE_SENTMSG2 upon valid incoming message 1 (then abort resolution)
51 we abort resolution and
52 -> SITE_WAIT on timeout or resolution failure
54 -> SITE_SENTMSG2 upon valid incoming message 1 from higher priority end
55 -> SITE_SENTMSG3 upon valid incoming message 2
56 -> SITE_WAIT on timeout
58 -> SITE_SENTMSG4 upon valid incoming message 3
59 -> SITE_WAIT on timeout
61 -> SITE_SENTMSG5 upon valid incoming message 4
62 -> SITE_WAIT on timeout
64 -> SITE_RUN upon valid incoming message 5
65 -> SITE_WAIT on timeout
67 -> SITE_RUN upon valid incoming message 6
68 -> SITE_WAIT on timeout
69 SITE_WAIT - failed to establish key; do nothing for a while
70 -> SITE_RUN on timeout
75 #define SITE_RESOLVE 2
76 #define SITE_SENTMSG1 3
77 #define SITE_SENTMSG2 4
78 #define SITE_SENTMSG3 5
79 #define SITE_SENTMSG4 6
80 #define SITE_SENTMSG5 7
83 static cstring_t state_name(uint32_t state)
86 case 0: return "STOP";
88 case 2: return "RESOLVE";
89 case 3: return "SENTMSG1";
90 case 4: return "SENTMSG2";
91 case 5: return "SENTMSG3";
92 case 6: return "SENTMSG4";
93 case 7: return "SENTMSG5";
94 case 8: return "WAIT";
95 default: return "*bad state*";
101 #define LOG_UNEXPECTED 0x00000001
102 #define LOG_SETUP_INIT 0x00000002
103 #define LOG_SETUP_TIMEOUT 0x00000004
104 #define LOG_ACTIVATE_KEY 0x00000008
105 #define LOG_TIMEOUT_KEY 0x00000010
106 #define LOG_SEC 0x00000020
107 #define LOG_STATE 0x00000040
108 #define LOG_DROP 0x00000080
109 #define LOG_DUMP 0x00000100
110 #define LOG_ERROR 0x00000400
112 static struct flagstr log_event_table[]={
113 { "unexpected", LOG_UNEXPECTED },
114 { "setup-init", LOG_SETUP_INIT },
115 { "setup-timeout", LOG_SETUP_TIMEOUT },
116 { "activate-key", LOG_ACTIVATE_KEY },
117 { "timeout-key", LOG_TIMEOUT_KEY },
118 { "security", LOG_SEC },
119 { "state-change", LOG_STATE },
120 { "packet-drop", LOG_DROP },
121 { "dump-packets", LOG_DUMP },
122 { "errors", LOG_ERROR },
123 { "default", LOG_SETUP_INIT|LOG_SETUP_TIMEOUT|
124 LOG_ACTIVATE_KEY|LOG_TIMEOUT_KEY|LOG_SEC|LOG_ERROR },
125 { "all", 0xffffffff },
132 /* configuration information */
135 string_t tunname; /* localname<->remotename by default, used in logs */
136 string_t address; /* DNS name for bootstrapping, optional */
137 int remoteport; /* Port for bootstrapping, optional */
138 struct netlink_if *netlink;
139 struct comm_if *comm;
140 struct resolver_if *resolver;
142 struct random_if *random;
143 struct rsaprivkey_if *privkey;
144 struct rsapubkey_if *pubkey;
145 struct transform_if *transform;
147 struct hash_if *hash;
149 uint32_t index; /* Index of this site */
150 int32_t setup_retries; /* How many times to send setup packets */
151 int32_t setup_timeout; /* Initial timeout for setup packets */
152 int32_t wait_timeout; /* How long to wait if setup unsuccessful */
153 int32_t key_lifetime; /* How long a key lasts once set up */
154 int32_t key_renegotiate_time; /* If we see traffic (or a keepalive)
155 after this time, initiate a new
158 uint8_t *setupsig; /* Expected signature of incoming MSG1 packets */
159 int32_t setupsiglen; /* Allows us to discard packets quickly if
160 they are not for us */
161 bool_t setup_priority; /* Do we have precedence if both sites emit
162 message 1 simultaneously? */
165 /* runtime information */
167 uint64_t now; /* Most recently seen time */
169 /* The currently established session */
170 uint32_t remote_session_id;
171 struct transform_inst_if *current_transform;
172 bool_t current_valid;
173 uint64_t current_key_timeout; /* End of life of current key */
174 uint64_t renegotiate_key_time; /* When we can negotiate a new key */
175 struct sockaddr_in peer; /* Current address of peer */
176 bool_t peer_valid; /* Peer address becomes invalid when key times out,
177 but only if we have a DNS name for our peer */
179 /* The current key setup protocol exchange. We can only be
180 involved in one of these at a time. There's a potential for
181 denial of service here (the attacker keeps sending a setup
182 packet; we keep trying to continue the exchange, and have to
183 timeout before we can listen for another setup packet); perhaps
184 we should keep a list of 'bad' sources for setup packets. */
185 uint32_t setup_session_id;
186 struct sockaddr_in setup_peer;
187 uint8_t localN[NONCELEN]; /* Nonces for key exchange */
188 uint8_t remoteN[NONCELEN];
189 struct buffer_if buffer; /* Current outgoing key exchange packet */
190 int32_t retries; /* Number of retries remaining */
191 uint64_t timeout; /* Timeout for current state */
193 uint8_t *sharedsecret;
194 struct transform_inst_if *new_transform; /* For key setup/verify */
197 static void slog(struct site *st, uint32_t event, cstring_t msg, ...)
205 if (event&st->log_events) {
207 case LOG_UNEXPECTED: class=M_INFO; break;
208 case LOG_SETUP_INIT: class=M_INFO; break;
209 case LOG_SETUP_TIMEOUT: class=M_NOTICE; break;
210 case LOG_ACTIVATE_KEY: class=M_INFO; break;
211 case LOG_TIMEOUT_KEY: class=M_INFO; break;
212 case LOG_SEC: class=M_SECURITY; break;
213 case LOG_STATE: class=M_DEBUG; break;
214 case LOG_DROP: class=M_DEBUG; break;
215 case LOG_DUMP: class=M_DEBUG; break;
216 case LOG_ERROR: class=M_ERR; break;
217 default: class=M_ERR; break;
220 vsnprintf(buf,sizeof(buf),msg,ap);
221 st->log->log(st->log->st,class,"%s: %s",st->tunname,buf);
226 static void set_link_quality(struct site *st);
227 static void delete_key(struct site *st, cstring_t reason, uint32_t loglevel);
228 static bool_t initiate_key_setup(struct site *st, cstring_t reason);
229 static void enter_state_run(struct site *st);
230 static bool_t enter_state_resolve(struct site *st);
231 static bool_t enter_new_state(struct site *st,uint32_t next);
232 static void enter_state_wait(struct site *st);
234 #define CHECK_AVAIL(b,l) do { if ((b)->size<(l)) return False; } while(0)
235 #define CHECK_EMPTY(b) do { if ((b)->size!=0) return False; } while(0)
236 #define CHECK_TYPE(b,t) do { uint32_t type; \
237 CHECK_AVAIL((b),4); \
238 type=buf_unprepend_uint32((b)); \
239 if (type!=(t)) return False; } while(0)
258 /* Build any of msg1 to msg4. msg5 and msg6 are built from the inside
259 out using a transform of config data supplied by netlink */
260 static bool_t generate_msg(struct site *st, uint32_t type, cstring_t what)
266 st->retries=st->setup_retries;
267 BUF_ALLOC(&st->buffer,what);
268 buffer_init(&st->buffer,0);
269 buf_append_uint32(&st->buffer,
270 (type==LABEL_MSG1?0:st->setup_session_id));
271 buf_append_uint32(&st->buffer,st->index);
272 buf_append_uint32(&st->buffer,type);
273 buf_append_string(&st->buffer,st->localname);
274 buf_append_string(&st->buffer,st->remotename);
275 memcpy(buf_append(&st->buffer,NONCELEN),st->localN,NONCELEN);
276 if (type==LABEL_MSG1) return True;
277 memcpy(buf_append(&st->buffer,NONCELEN),st->remoteN,NONCELEN);
278 if (type==LABEL_MSG2) return True;
280 if (hacky_par_mid_failnow()) return False;
282 dhpub=st->dh->makepublic(st->dh->st,st->dhsecret,st->dh->len);
283 buf_append_string(&st->buffer,dhpub);
285 hash=safe_malloc(st->hash->len, "generate_msg");
286 hst=st->hash->init();
287 st->hash->update(hst,st->buffer.start,st->buffer.size);
288 st->hash->final(hst,hash);
289 sig=st->privkey->sign(st->privkey->st,hash,st->hash->len);
290 buf_append_string(&st->buffer,sig);
296 static bool_t unpick_msg(struct site *st, uint32_t type,
297 struct buffer_if *msg, struct msg *m)
299 m->hashstart=msg->start;
301 m->dest=buf_unprepend_uint32(msg);
303 m->source=buf_unprepend_uint32(msg);
304 CHECK_TYPE(msg,type);
306 m->remlen=buf_unprepend_uint16(msg);
307 CHECK_AVAIL(msg,m->remlen);
308 m->remote=buf_unprepend(msg,m->remlen);
310 m->loclen=buf_unprepend_uint16(msg);
311 CHECK_AVAIL(msg,m->loclen);
312 m->local=buf_unprepend(msg,m->loclen);
313 CHECK_AVAIL(msg,NONCELEN);
314 m->nR=buf_unprepend(msg,NONCELEN);
315 if (type==LABEL_MSG1) {
319 CHECK_AVAIL(msg,NONCELEN);
320 m->nL=buf_unprepend(msg,NONCELEN);
321 if (type==LABEL_MSG2) {
326 m->pklen=buf_unprepend_uint16(msg);
327 CHECK_AVAIL(msg,m->pklen);
328 m->pk=buf_unprepend(msg,m->pklen);
329 m->hashlen=msg->start-m->hashstart;
331 m->siglen=buf_unprepend_uint16(msg);
332 CHECK_AVAIL(msg,m->siglen);
333 m->sig=buf_unprepend(msg,m->siglen);
338 static bool_t check_msg(struct site *st, uint32_t type, struct msg *m,
341 if (type==LABEL_MSG1) return True;
343 /* Check that the site names and our nonce have been sent
344 back correctly, and then store our peer's nonce. */
345 if (memcmp(m->remote,st->remotename,strlen(st->remotename)!=0)) {
346 *error="wrong remote site name";
349 if (memcmp(m->local,st->localname,strlen(st->localname)!=0)) {
350 *error="wrong local site name";
353 if (memcmp(m->nL,st->localN,NONCELEN)!=0) {
354 *error="wrong locally-generated nonce";
357 if (type==LABEL_MSG2) return True;
358 if (memcmp(m->nR,st->remoteN,NONCELEN)!=0) {
359 *error="wrong remotely-generated nonce";
362 if (type==LABEL_MSG3) return True;
363 if (type==LABEL_MSG4) return True;
364 *error="unknown message type";
368 static bool_t generate_msg1(struct site *st)
370 st->random->generate(st->random->st,NONCELEN,st->localN);
371 return generate_msg(st,LABEL_MSG1,"site:MSG1");
374 static bool_t process_msg1(struct site *st, struct buffer_if *msg1,
375 struct sockaddr_in *src)
379 /* We've already determined we're in an appropriate state to
380 process an incoming MSG1, and that the MSG1 has correct values
383 if (!unpick_msg(st,LABEL_MSG1,msg1,&m)) return False;
386 st->setup_session_id=m.source;
387 memcpy(st->remoteN,m.nR,NONCELEN);
391 static bool_t generate_msg2(struct site *st)
393 st->random->generate(st->random->st,NONCELEN,st->localN);
394 return generate_msg(st,LABEL_MSG2,"site:MSG2");
397 static bool_t process_msg2(struct site *st, struct buffer_if *msg2,
398 struct sockaddr_in *src)
403 if (!unpick_msg(st,LABEL_MSG2,msg2,&m)) return False;
404 if (!check_msg(st,LABEL_MSG2,&m,&err)) {
405 slog(st,LOG_SEC,"msg2: %s",err);
408 st->setup_session_id=m.source;
409 memcpy(st->remoteN,m.nR,NONCELEN);
413 static bool_t generate_msg3(struct site *st)
415 /* Now we have our nonce and their nonce. Think of a secret key,
416 and create message number 3. */
417 st->random->generate(st->random->st,st->dh->len,st->dhsecret);
418 return generate_msg(st,LABEL_MSG3,"site:MSG3");
421 static bool_t process_msg3(struct site *st, struct buffer_if *msg3,
422 struct sockaddr_in *src)
429 if (!unpick_msg(st,LABEL_MSG3,msg3,&m)) return False;
430 if (!check_msg(st,LABEL_MSG3,&m,&err)) {
431 slog(st,LOG_SEC,"msg3: %s",err);
435 /* Check signature and store g^x mod m */
436 hash=safe_malloc(st->hash->len, "process_msg3");
437 hst=st->hash->init();
438 st->hash->update(hst,m.hashstart,m.hashlen);
439 st->hash->final(hst,hash);
440 /* Terminate signature with a '0' - cheating, but should be ok */
442 if (!st->pubkey->check(st->pubkey->st,hash,st->hash->len,m.sig)) {
443 slog(st,LOG_SEC,"msg3 signature failed check!");
449 /* Terminate their DH public key with a '0' */
451 /* Invent our DH secret key */
452 st->random->generate(st->random->st,st->dh->len,st->dhsecret);
454 /* Generate the shared key */
455 st->dh->makeshared(st->dh->st,st->dhsecret,st->dh->len,m.pk,
456 st->sharedsecret,st->transform->keylen);
458 /* Set up the transform */
459 st->new_transform->setkey(st->new_transform->st,st->sharedsecret,
460 st->transform->keylen);
465 static bool_t generate_msg4(struct site *st)
467 /* We have both nonces, their public key and our private key. Generate
468 our public key, sign it and send it to them. */
469 return generate_msg(st,LABEL_MSG4,"site:MSG4");
472 static bool_t process_msg4(struct site *st, struct buffer_if *msg4,
473 struct sockaddr_in *src)
480 if (!unpick_msg(st,LABEL_MSG4,msg4,&m)) return False;
481 if (!check_msg(st,LABEL_MSG4,&m,&err)) {
482 slog(st,LOG_SEC,"msg4: %s",err);
486 /* Check signature and store g^x mod m */
487 hash=safe_malloc(st->hash->len, "process_msg4");
488 hst=st->hash->init();
489 st->hash->update(hst,m.hashstart,m.hashlen);
490 st->hash->final(hst,hash);
491 /* Terminate signature with a '0' - cheating, but should be ok */
493 if (!st->pubkey->check(st->pubkey->st,hash,st->hash->len,m.sig)) {
494 slog(st,LOG_SEC,"msg4 signature failed check!");
500 /* Terminate their DH public key with a '0' */
502 /* Generate the shared key */
503 st->dh->makeshared(st->dh->st,st->dhsecret,st->dh->len,m.pk,
504 st->sharedsecret,st->transform->keylen);
505 /* Set up the transform */
506 st->new_transform->setkey(st->new_transform->st,st->sharedsecret,
507 st->transform->keylen);
518 static bool_t unpick_msg0(struct site *st, struct buffer_if *msg0,
522 m->dest=buf_unprepend_uint32(msg0);
524 m->source=buf_unprepend_uint32(msg0);
526 m->type=buf_unprepend_uint32(msg0);
528 /* Leaves transformed part of buffer untouched */
531 static bool_t generate_msg5(struct site *st)
533 cstring_t transform_err;
535 BUF_ALLOC(&st->buffer,"site:MSG5");
536 /* We are going to add four words to the message */
537 buffer_init(&st->buffer,st->transform->max_start_pad+(4*4));
538 /* Give the netlink code an opportunity to put its own stuff in the
539 message (configuration information, etc.) */
540 st->netlink->output_config(st->netlink->st,&st->buffer);
541 buf_prepend_uint32(&st->buffer,LABEL_MSG5);
542 st->new_transform->forwards(st->new_transform->st,&st->buffer,
544 buf_prepend_uint32(&st->buffer,LABEL_MSG5);
545 buf_prepend_uint32(&st->buffer,st->index);
546 buf_prepend_uint32(&st->buffer,st->setup_session_id);
548 st->retries=st->setup_retries;
552 static bool_t process_msg5(struct site *st, struct buffer_if *msg5,
553 struct sockaddr_in *src)
556 cstring_t transform_err;
558 if (!unpick_msg0(st,msg5,&m)) return False;
560 if (st->new_transform->reverse(st->new_transform->st,
561 msg5,&transform_err)) {
562 /* There's a problem */
563 slog(st,LOG_SEC,"process_msg5: transform: %s",transform_err);
566 /* Buffer should now contain untransformed PING packet data */
568 if (buf_unprepend_uint32(msg5)!=LABEL_MSG5) {
569 slog(st,LOG_SEC,"MSG5/PING packet contained wrong label");
572 if (!st->netlink->check_config(st->netlink->st,msg5)) {
573 slog(st,LOG_SEC,"MSG5/PING packet contained bad netlink config");
580 static bool_t generate_msg6(struct site *st)
582 cstring_t transform_err;
584 BUF_ALLOC(&st->buffer,"site:MSG6");
585 /* We are going to add four words to the message */
586 buffer_init(&st->buffer,st->transform->max_start_pad+(4*4));
587 /* Give the netlink code an opportunity to put its own stuff in the
588 message (configuration information, etc.) */
589 st->netlink->output_config(st->netlink->st,&st->buffer);
590 buf_prepend_uint32(&st->buffer,LABEL_MSG6);
591 st->new_transform->forwards(st->new_transform->st,&st->buffer,
593 buf_prepend_uint32(&st->buffer,LABEL_MSG6);
594 buf_prepend_uint32(&st->buffer,st->index);
595 buf_prepend_uint32(&st->buffer,st->setup_session_id);
597 st->retries=1; /* Peer will retransmit MSG5 if this packet gets lost */
601 static bool_t process_msg6(struct site *st, struct buffer_if *msg6,
602 struct sockaddr_in *src)
605 cstring_t transform_err;
607 if (!unpick_msg0(st,msg6,&m)) return False;
609 if (st->new_transform->reverse(st->new_transform->st,
610 msg6,&transform_err)) {
611 /* There's a problem */
612 slog(st,LOG_SEC,"process_msg6: transform: %s",transform_err);
615 /* Buffer should now contain untransformed PING packet data */
617 if (buf_unprepend_uint32(msg6)!=LABEL_MSG6) {
618 slog(st,LOG_SEC,"MSG6/PONG packet contained invalid data");
621 if (!st->netlink->check_config(st->netlink->st,msg6)) {
622 slog(st,LOG_SEC,"MSG6/PONG packet contained bad netlink config");
629 static bool_t process_msg0(struct site *st, struct buffer_if *msg0,
630 struct sockaddr_in *src)
633 cstring_t transform_err;
636 if (!st->current_valid) {
637 slog(st,LOG_DROP,"incoming message but no current key -> dropping");
638 return initiate_key_setup(st,"incoming message but no current key");
641 if (!unpick_msg0(st,msg0,&m)) return False;
643 if (st->current_transform->reverse(st->current_transform->st,
644 msg0,&transform_err)) {
645 /* There's a problem */
646 slog(st,LOG_SEC,"transform: %s",transform_err);
647 return initiate_key_setup(st,"incoming message would not decrypt");
650 type=buf_unprepend_uint32(msg0);
653 /* We must forget about the current session. */
654 delete_key(st,"request from peer",LOG_SEC);
657 /* Deliver to netlink layer */
658 st->netlink->deliver(st->netlink->st,msg0);
661 slog(st,LOG_SEC,"incoming encrypted message of type %08x "
668 static void dump_packet(struct site *st, struct buffer_if *buf,
669 struct sockaddr_in *addr, bool_t incoming)
671 uint32_t dest=ntohl(*(uint32_t *)buf->start);
672 uint32_t source=ntohl(*(uint32_t *)(buf->start+4));
673 uint32_t msgtype=ntohl(*(uint32_t *)(buf->start+8));
675 if (st->log_events & LOG_DUMP)
676 slilog(st->log,M_DEBUG,"%s: %s: %08x<-%08x: %08x:",
677 st->tunname,incoming?"incoming":"outgoing",
678 dest,source,msgtype);
681 static uint32_t site_status(void *st)
686 static bool_t send_msg(struct site *st)
689 dump_packet(st,&st->buffer,&st->setup_peer,False);
690 st->comm->sendmsg(st->comm->st,&st->buffer,&st->setup_peer);
691 st->timeout=st->now+st->setup_timeout;
695 slog(st,LOG_SETUP_TIMEOUT,"timed out sending key setup packet "
696 "(in state %s)",state_name(st->state));
697 enter_state_wait(st);
702 static void site_resolve_callback(void *sst, struct in_addr *address)
706 if (st->state!=SITE_RESOLVE) {
707 slog(st,LOG_UNEXPECTED,"site_resolve_callback called unexpectedly");
711 memset(&st->setup_peer,0,sizeof(st->setup_peer));
712 st->setup_peer.sin_family=AF_INET;
713 st->setup_peer.sin_port=htons(st->remoteport);
714 st->setup_peer.sin_addr=*address;
715 enter_new_state(st,SITE_SENTMSG1);
717 /* Resolution failed */
718 slog(st,LOG_ERROR,"resolution of %s failed",st->address);
723 static bool_t initiate_key_setup(struct site *st, cstring_t reason)
725 if (st->state!=SITE_RUN) return False;
726 slog(st,LOG_SETUP_INIT,"initiating key exchange (%s)",reason);
728 slog(st,LOG_SETUP_INIT,"resolving peer address");
729 return enter_state_resolve(st);
730 } else if (st->peer_valid) {
731 slog(st,LOG_SETUP_INIT,"using old peer address");
732 st->setup_peer=st->peer;
733 return enter_new_state(st,SITE_SENTMSG1);
735 slog(st,LOG_SETUP_INIT,"key exchange failed: no address for peer");
739 static void activate_new_key(struct site *st)
741 struct transform_inst_if *t;
743 /* We have two transform instances, which we swap between active
745 t=st->current_transform;
746 st->current_transform=st->new_transform;
751 st->current_valid=True;
752 st->current_key_timeout=st->now+st->key_lifetime;
753 st->renegotiate_key_time=st->now+st->key_renegotiate_time;
754 st->peer=st->setup_peer;
756 st->remote_session_id=st->setup_session_id;
758 slog(st,LOG_ACTIVATE_KEY,"new key activated");
762 static void delete_key(struct site *st, cstring_t reason, uint32_t loglevel)
764 if (st->current_valid) {
765 slog(st,loglevel,"session closed (%s)",reason);
767 st->current_valid=False;
768 st->current_transform->delkey(st->current_transform->st);
769 st->current_key_timeout=0;
770 set_link_quality(st);
774 static void state_assert(struct site *st, bool_t ok)
776 if (!ok) fatal("site:state_assert");
779 static void enter_state_stop(struct site *st)
783 delete_key(st,"entering state STOP",LOG_TIMEOUT_KEY);
784 st->new_transform->delkey(st->new_transform->st);
787 static void set_link_quality(struct site *st)
790 if (st->current_valid)
791 quality=LINK_QUALITY_UP;
792 else if (st->state==SITE_WAIT || st->state==SITE_STOP)
793 quality=LINK_QUALITY_DOWN;
794 else if (st->address)
795 quality=LINK_QUALITY_DOWN_CURRENT_ADDRESS;
796 else if (st->peer_valid)
797 quality=LINK_QUALITY_DOWN_STALE_ADDRESS;
799 quality=LINK_QUALITY_DOWN;
801 st->netlink->set_quality(st->netlink->st,quality);
804 static void enter_state_run(struct site *st)
806 slog(st,LOG_STATE,"entering state RUN");
810 st->setup_session_id=0;
811 memset(&st->setup_peer,0,sizeof(st->setup_peer));
812 memset(st->localN,0,NONCELEN);
813 memset(st->remoteN,0,NONCELEN);
814 st->new_transform->delkey(st->new_transform->st);
815 memset(st->dhsecret,0,st->dh->len);
816 memset(st->sharedsecret,0,st->transform->keylen);
817 set_link_quality(st);
820 static bool_t enter_state_resolve(struct site *st)
822 state_assert(st,st->state==SITE_RUN);
823 slog(st,LOG_STATE,"entering state RESOLVE");
824 st->state=SITE_RESOLVE;
825 st->resolver->request(st->resolver->st,st->address,
826 site_resolve_callback,st);
830 static bool_t enter_new_state(struct site *st, uint32_t next)
832 bool_t (*gen)(struct site *st);
835 slog(st,LOG_STATE,"entering state %s",state_name(next));
838 state_assert(st,st->state==SITE_RUN || st->state==SITE_RESOLVE);
842 state_assert(st,st->state==SITE_RUN || st->state==SITE_RESOLVE ||
843 st->state==SITE_SENTMSG1 || st->state==SITE_WAIT);
847 state_assert(st,st->state==SITE_SENTMSG1);
848 BUF_FREE(&st->buffer);
852 state_assert(st,st->state==SITE_SENTMSG2);
853 BUF_FREE(&st->buffer);
857 state_assert(st,st->state==SITE_SENTMSG3);
858 BUF_FREE(&st->buffer);
862 state_assert(st,st->state==SITE_SENTMSG4);
863 BUF_FREE(&st->buffer);
868 fatal("enter_new_state(%s): invalid new state",state_name(next));
872 if (hacky_par_start_failnow()) return False;
874 r= gen(st) && send_msg(st);
877 st->setup_retries, st->setup_timeout,
882 if (next==SITE_RUN) {
883 BUF_FREE(&st->buffer); /* Never reused */
884 st->timeout=0; /* Never retransmit */
885 activate_new_key(st);
889 slog(st,LOG_ERROR,"error entering state %s",state_name(next));
890 st->buffer.free=False; /* Unconditionally use the buffer; it may be
891 in either state, and enter_state_wait() will
893 enter_state_wait(st);
897 /* msg7 tells our peer that we're about to forget our key */
898 static bool_t send_msg7(struct site *st, cstring_t reason)
900 cstring_t transform_err;
902 if (st->current_valid && st->peer_valid && st->buffer.free) {
903 BUF_ALLOC(&st->buffer,"site:MSG7");
904 buffer_init(&st->buffer,st->transform->max_start_pad+(4*3));
905 buf_append_uint32(&st->buffer,LABEL_MSG7);
906 buf_append_string(&st->buffer,reason);
907 st->current_transform->forwards(st->current_transform->st,
908 &st->buffer, &transform_err);
909 buf_prepend_uint32(&st->buffer,LABEL_MSG0);
910 buf_prepend_uint32(&st->buffer,st->index);
911 buf_prepend_uint32(&st->buffer,st->remote_session_id);
912 dump_packet(st,&st->buffer,&st->peer,False);
913 st->comm->sendmsg(st->comm->st,&st->buffer,&st->peer);
914 BUF_FREE(&st->buffer);
920 /* We go into this state if our peer becomes uncommunicative. Similar to
921 the "stop" state, we forget all session keys for a while, before
922 re-entering the "run" state. */
923 static void enter_state_wait(struct site *st)
925 slog(st,LOG_STATE,"entering state WAIT");
926 st->timeout=st->now+st->wait_timeout;
928 set_link_quality(st);
929 BUF_FREE(&st->buffer); /* will have had an outgoing packet in it */
930 /* XXX Erase keys etc. */
933 static inline void site_settimeout(uint64_t timeout, int *timeout_io)
936 int64_t offset=timeout-*now;
937 if (offset<0) offset=0;
938 if (offset>INT_MAX) offset=INT_MAX;
939 if (*timeout_io<0 || offset<*timeout_io)
944 static int site_beforepoll(void *sst, struct pollfd *fds, int *nfds_io,
949 *nfds_io=0; /* We don't use any file descriptors */
952 /* Work out when our next timeout is. The earlier of 'timeout' or
953 'current_key_timeout'. A stored value of '0' indicates no timeout
955 site_settimeout(st->timeout, timeout_io);
956 site_settimeout(st->current_key_timeout, timeout_io);
958 return 0; /* success */
961 /* NB site_afterpoll will be called before site_beforepoll is ever called */
962 static void site_afterpoll(void *sst, struct pollfd *fds, int nfds)
967 if (st->timeout && *now>st->timeout) {
969 if (st->state>=SITE_SENTMSG1 && st->state<=SITE_SENTMSG5) {
970 if (!hacky_par_start_failnow())
972 } else if (st->state==SITE_WAIT) {
975 slog(st,LOG_ERROR,"site_afterpoll: unexpected timeout, state=%d",
979 if (st->current_key_timeout && *now>st->current_key_timeout) {
980 delete_key(st,"maximum key life exceeded",LOG_TIMEOUT_KEY);
984 /* This function is called by the netlink device to deliver packets
985 intended for the remote network. The packet is in "raw" wire
986 format, but is guaranteed to be word-aligned. */
987 static void site_outgoing(void *sst, struct buffer_if *buf)
990 cstring_t transform_err;
992 if (st->state==SITE_STOP) {
997 /* In all other states we consider delivering the packet if we have
998 a valid key and a valid address to send it to. */
999 if (st->current_valid && st->peer_valid) {
1000 /* Transform it and send it */
1002 buf_prepend_uint32(buf,LABEL_MSG9);
1003 st->current_transform->forwards(st->current_transform->st,
1004 buf, &transform_err);
1005 buf_prepend_uint32(buf,LABEL_MSG0);
1006 buf_prepend_uint32(buf,st->index);
1007 buf_prepend_uint32(buf,st->remote_session_id);
1008 st->comm->sendmsg(st->comm->st,buf,&st->peer);
1011 /* See whether we should start negotiating a new key */
1012 if (st->now > st->renegotiate_key_time)
1013 initiate_key_setup(st,"outgoing packet in renegotiation window");
1017 slog(st,LOG_DROP,"discarding outgoing packet of size %d",buf->size);
1019 initiate_key_setup(st,"outgoing packet");
1022 /* This function is called by the communication device to deliver
1023 packets from our peers. */
1024 static bool_t site_incoming(void *sst, struct buffer_if *buf,
1025 struct sockaddr_in *source)
1027 struct site *st=sst;
1028 uint32_t dest=ntohl(*(uint32_t *)buf->start);
1031 /* It could be for any site - it should have LABEL_MSG1 and
1032 might have our name and our peer's name in it */
1033 if (buf->size<(st->setupsiglen+8+NONCELEN)) return False;
1034 if (memcmp(buf->start+8,st->setupsig,st->setupsiglen)==0) {
1035 /* It's addressed to us. Decide what to do about it. */
1036 dump_packet(st,buf,source,True);
1037 if (st->state==SITE_RUN || st->state==SITE_RESOLVE ||
1038 st->state==SITE_WAIT) {
1039 /* We should definitely process it */
1040 if (process_msg1(st,buf,source)) {
1041 slog(st,LOG_SETUP_INIT,"key setup initiated by peer");
1042 enter_new_state(st,SITE_SENTMSG2);
1044 slog(st,LOG_ERROR,"failed to process incoming msg1");
1048 } else if (st->state==SITE_SENTMSG1) {
1049 /* We've just sent a message 1! They may have crossed on
1050 the wire. If we have priority then we ignore the
1051 incoming one, otherwise we process it as usual. */
1052 if (st->setup_priority) {
1054 slog(st,LOG_DUMP,"crossed msg1s; we are higher "
1055 "priority => ignore incoming msg1");
1058 slog(st,LOG_DUMP,"crossed msg1s; we are lower "
1059 "priority => use incoming msg1");
1060 if (process_msg1(st,buf,source)) {
1061 BUF_FREE(&st->buffer); /* Free our old message 1 */
1062 enter_new_state(st,SITE_SENTMSG2);
1064 slog(st,LOG_ERROR,"failed to process an incoming "
1065 "crossed msg1 (we have low priority)");
1071 /* The message 1 was received at an unexpected stage of the
1072 key setup. XXX POLICY - what do we do? */
1073 slog(st,LOG_UNEXPECTED,"unexpected incoming message 1");
1077 return False; /* Not for us. */
1079 if (dest==st->index) {
1080 /* Explicitly addressed to us */
1081 uint32_t msgtype=ntohl(get_uint32(buf->start+8));
1082 if (msgtype!=LABEL_MSG0) dump_packet(st,buf,source,True);
1085 /* If the source is our current peer then initiate a key setup,
1086 because our peer's forgotten the key */
1087 if (get_uint32(buf->start+4)==st->remote_session_id) {
1088 initiate_key_setup(st,"received a NAK");
1090 slog(st,LOG_SEC,"bad incoming NAK");
1094 process_msg0(st,buf,source);
1097 /* Setup packet: should not have been explicitly addressed
1099 slog(st,LOG_SEC,"incoming explicitly addressed msg1");
1102 /* Setup packet: expected only in state SENTMSG1 */
1103 if (st->state!=SITE_SENTMSG1) {
1104 slog(st,LOG_UNEXPECTED,"unexpected MSG2");
1105 } else if (process_msg2(st,buf,source))
1106 enter_new_state(st,SITE_SENTMSG3);
1108 slog(st,LOG_SEC,"invalid MSG2");
1112 /* Setup packet: expected only in state SENTMSG2 */
1113 if (st->state!=SITE_SENTMSG2) {
1114 slog(st,LOG_UNEXPECTED,"unexpected MSG3");
1115 } else if (process_msg3(st,buf,source))
1116 enter_new_state(st,SITE_SENTMSG4);
1118 slog(st,LOG_SEC,"invalid MSG3");
1122 /* Setup packet: expected only in state SENTMSG3 */
1123 if (st->state!=SITE_SENTMSG3) {
1124 slog(st,LOG_UNEXPECTED,"unexpected MSG4");
1125 } else if (process_msg4(st,buf,source))
1126 enter_new_state(st,SITE_SENTMSG5);
1128 slog(st,LOG_SEC,"invalid MSG4");
1132 /* Setup packet: expected only in state SENTMSG4 */
1133 /* (may turn up in state RUN if our return MSG6 was lost
1134 and the new key has already been activated. In that
1135 case we should treat it as an ordinary PING packet. We
1136 can't pass it to process_msg5() because the
1137 new_transform will now be unkeyed. XXX) */
1138 if (st->state!=SITE_SENTMSG4) {
1139 slog(st,LOG_UNEXPECTED,"unexpected MSG5");
1140 } else if (process_msg5(st,buf,source)) {
1141 enter_new_state(st,SITE_RUN);
1143 slog(st,LOG_SEC,"invalid MSG5");
1147 /* Setup packet: expected only in state SENTMSG5 */
1148 if (st->state!=SITE_SENTMSG5) {
1149 slog(st,LOG_UNEXPECTED,"unexpected MSG6");
1150 } else if (process_msg6(st,buf,source)) {
1151 BUF_FREE(&st->buffer); /* Free message 5 */
1152 activate_new_key(st);
1154 slog(st,LOG_SEC,"invalid MSG6");
1158 slog(st,LOG_SEC,"received message of unknown type 0x%08x",
1169 static void site_control(void *vst, bool_t run)
1171 struct site *st=vst;
1172 if (run) enter_state_run(st);
1173 else enter_state_stop(st);
1176 static void site_phase_hook(void *sst, uint32_t newphase)
1178 struct site *st=sst;
1180 /* The program is shutting down; tell our peer */
1181 send_msg7(st,"shutting down");
1184 static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context,
1187 static uint32_t index_sequence;
1192 st=safe_malloc(sizeof(*st),"site_apply");
1194 st->cl.description="site";
1195 st->cl.type=CL_SITE;
1197 st->cl.interface=&st->ops;
1199 st->ops.control=site_control;
1200 st->ops.status=site_status;
1202 /* First parameter must be a dict */
1203 item=list_elem(args,0);
1204 if (!item || item->type!=t_dict)
1205 cfgfatal(loc,"site","parameter must be a dictionary\n");
1207 dict=item->data.dict;
1208 st->localname=dict_read_string(dict, "local-name", True, "site", loc);
1209 st->remotename=dict_read_string(dict, "name", True, "site", loc);
1210 /* Sanity check (which also allows the 'sites' file to include
1211 site() closures for all sites including our own): refuse to
1212 talk to ourselves */
1213 if (strcmp(st->localname,st->remotename)==0) {
1214 Message(M_DEBUG,"site %s: local-name==name -> ignoring this site\n",
1219 assert(index_sequence < 0xffffffffUL);
1220 st->index = ++index_sequence;
1221 st->netlink=find_cl_if(dict,"link",CL_NETLINK,True,"site",loc);
1222 st->comm=find_cl_if(dict,"comm",CL_COMM,True,"site",loc);
1223 st->resolver=find_cl_if(dict,"resolver",CL_RESOLVER,True,"site",loc);
1224 st->log=find_cl_if(dict,"log",CL_LOG,True,"site",loc);
1225 st->random=find_cl_if(dict,"random",CL_RANDOMSRC,True,"site",loc);
1227 st->privkey=find_cl_if(dict,"local-key",CL_RSAPRIVKEY,True,"site",loc);
1228 st->address=dict_read_string(dict, "address", False, "site", loc);
1230 st->remoteport=dict_read_number(dict,"port",True,"site",loc,0);
1231 else st->remoteport=0;
1232 st->pubkey=find_cl_if(dict,"key",CL_RSAPUBKEY,True,"site",loc);
1235 find_cl_if(dict,"transform",CL_TRANSFORM,True,"site",loc);
1237 st->dh=find_cl_if(dict,"dh",CL_DH,True,"site",loc);
1238 st->hash=find_cl_if(dict,"hash",CL_HASH,True,"site",loc);
1240 st->key_lifetime=dict_read_number(
1241 dict,"key-lifetime",False,"site",loc,DEFAULT_KEY_LIFETIME);
1242 st->setup_retries=dict_read_number(
1243 dict,"setup-retries",False,"site",loc,DEFAULT_SETUP_RETRIES);
1244 st->setup_timeout=dict_read_number(
1245 dict,"setup-timeout",False,"site",loc,DEFAULT_SETUP_TIMEOUT);
1246 st->wait_timeout=dict_read_number(
1247 dict,"wait-time",False,"site",loc,DEFAULT_WAIT_TIME);
1249 if (st->key_lifetime < DEFAULT_KEY_RENEGOTIATE_GAP*2)
1250 st->key_renegotiate_time=st->key_lifetime/2;
1252 st->key_renegotiate_time=st->key_lifetime-DEFAULT_KEY_RENEGOTIATE_GAP;
1253 st->key_renegotiate_time=dict_read_number(
1254 dict,"renegotiate-time",False,"site",loc,st->key_renegotiate_time);
1255 if (st->key_renegotiate_time > st->key_lifetime) {
1256 cfgfatal(loc,"site",
1257 "renegotiate-time must be less than key-lifetime\n");
1260 st->log_events=string_list_to_word(dict_lookup(dict,"log-events"),
1261 log_event_table,"site");
1263 st->tunname=safe_malloc(strlen(st->localname)+strlen(st->remotename)+5,
1265 sprintf(st->tunname,"%s<->%s",st->localname,st->remotename);
1267 /* The information we expect to see in incoming messages of type 1 */
1268 /* fixme: lots of unchecked overflows here, but the results are only
1269 corrupted packets rather than undefined behaviour */
1270 st->setupsiglen=strlen(st->remotename)+strlen(st->localname)+8;
1271 st->setupsig=safe_malloc(st->setupsiglen,"site_apply");
1272 put_uint32(st->setupsig+0,LABEL_MSG1);
1273 put_uint16(st->setupsig+4,strlen(st->remotename));
1274 memcpy(&st->setupsig[6],st->remotename,strlen(st->remotename));
1275 put_uint16(st->setupsig+(6+strlen(st->remotename)),strlen(st->localname));
1276 memcpy(&st->setupsig[8+strlen(st->remotename)],st->localname,
1277 strlen(st->localname));
1278 st->setup_priority=(strcmp(st->localname,st->remotename)>0);
1280 buffer_new(&st->buffer,SETUP_BUFFER_LEN);
1282 /* We are interested in poll(), but only for timeouts. We don't have
1283 any fds of our own. */
1284 register_for_poll(st, site_beforepoll, site_afterpoll, 0, "site");
1287 st->current_valid=False;
1288 st->current_key_timeout=0;
1289 st->peer_valid=False;
1290 /* XXX mlock these */
1291 st->dhsecret=safe_malloc(st->dh->len,"site:dhsecret");
1292 st->sharedsecret=safe_malloc(st->transform->keylen,"site:sharedsecret");
1294 /* We need to register the remote networks with the netlink device */
1295 st->netlink->reg(st->netlink->st, site_outgoing, st,
1296 st->transform->max_start_pad+(4*4)+
1297 st->comm->min_start_pad,
1298 st->transform->max_end_pad+st->comm->min_end_pad);
1300 st->comm->request_notify(st->comm->st, st, site_incoming);
1302 st->current_transform=st->transform->create(st->transform->st);
1303 st->new_transform=st->transform->create(st->transform->st);
1305 enter_state_stop(st);
1307 add_hook(PHASE_SHUTDOWN,site_phase_hook,st);
1309 return new_closure(&st->cl);
1312 void site_module(dict_t *dict)
1314 add_closure(dict,"site",site_apply);