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[dragonfly.git] / usr.sbin / pppd / ipcp.c
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1 /*
2 * ipcp.c - PPP IP Control Protocol.
4 * Copyright (c) 1989 Carnegie Mellon University.
5 * All rights reserved.
7 * Redistribution and use in source and binary forms are permitted
8 * provided that the above copyright notice and this paragraph are
9 * duplicated in all such forms and that any documentation,
10 * advertising materials, and other materials related to such
11 * distribution and use acknowledge that the software was developed
12 * by Carnegie Mellon University. The name of the
13 * University may not be used to endorse or promote products derived
14 * from this software without specific prior written permission.
15 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
17 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
19 * $FreeBSD: src/usr.sbin/pppd/ipcp.c,v 1.12 1999/08/28 01:19:03 peter Exp $
20 * $DragonFly: src/usr.sbin/pppd/ipcp.c,v 1.5 2007/11/25 01:28:24 swildner Exp $
24 * TODO:
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <string.h>
30 #include <syslog.h>
31 #include <netdb.h>
32 #include <sys/param.h>
33 #include <sys/types.h>
34 #include <sys/socket.h>
35 #include <netinet/in.h>
37 #include "pppd.h"
38 #include "fsm.h"
39 #include "ipcp.h"
40 #include "pathnames.h"
42 /* global vars */
43 ipcp_options ipcp_wantoptions[NUM_PPP]; /* Options that we want to request */
44 ipcp_options ipcp_gotoptions[NUM_PPP]; /* Options that peer ack'd */
45 ipcp_options ipcp_allowoptions[NUM_PPP]; /* Options we allow peer to request */
46 ipcp_options ipcp_hisoptions[NUM_PPP]; /* Options that we ack'd */
48 /* local vars */
49 static int cis_received[NUM_PPP]; /* # Conf-Reqs received */
50 static int default_route_set[NUM_PPP]; /* Have set up a default route */
51 static int proxy_arp_set[NUM_PPP]; /* Have created proxy arp entry */
54 * Callbacks for fsm code. (CI = Configuration Information)
56 static void ipcp_resetci(fsm *); /* Reset our CI */
57 static int ipcp_cilen(fsm *); /* Return length of our CI */
58 static void ipcp_addci(fsm *, u_char *, int *); /* Add our CI */
59 static int ipcp_ackci(fsm *, u_char *, int); /* Peer ack'd our CI */
60 static int ipcp_nakci(fsm *, u_char *, int); /* Peer nak'd our CI */
61 static int ipcp_rejci(fsm *, u_char *, int); /* Peer rej'd our CI */
62 static int ipcp_reqci(fsm *, u_char *, int *, int); /* Rcv CI */
63 static void ipcp_up(fsm *); /* We're UP */
64 static void ipcp_down(fsm *); /* We're DOWN */
65 static void ipcp_script(fsm *, char *); /* Run an up/down script */
66 static void ipcp_finished(fsm *); /* Don't need lower layer */
68 fsm ipcp_fsm[NUM_PPP]; /* IPCP fsm structure */
70 static fsm_callbacks ipcp_callbacks = { /* IPCP callback routines */
71 ipcp_resetci, /* Reset our Configuration Information */
72 ipcp_cilen, /* Length of our Configuration Information */
73 ipcp_addci, /* Add our Configuration Information */
74 ipcp_ackci, /* ACK our Configuration Information */
75 ipcp_nakci, /* NAK our Configuration Information */
76 ipcp_rejci, /* Reject our Configuration Information */
77 ipcp_reqci, /* Request peer's Configuration Information */
78 ipcp_up, /* Called when fsm reaches OPENED state */
79 ipcp_down, /* Called when fsm leaves OPENED state */
80 NULL, /* Called when we want the lower layer up */
81 ipcp_finished, /* Called when we want the lower layer down */
82 NULL, /* Called when Protocol-Reject received */
83 NULL, /* Retransmission is necessary */
84 NULL, /* Called to handle protocol-specific codes */
85 "IPCP" /* String name of protocol */
89 * Protocol entry points from main code.
91 static void ipcp_init(int);
92 static void ipcp_open(int);
93 static void ipcp_close(int, char *);
94 static void ipcp_lowerup(int);
95 static void ipcp_lowerdown(int);
96 static void ipcp_input(int, u_char *, int);
97 static void ipcp_protrej(int);
98 static int ipcp_printpkt(u_char *, int,
99 void (*)(void *, char *, ...), void *);
100 static void ip_check_options(void);
101 static int ip_demand_conf(int);
102 static int ip_active_pkt(u_char *, int);
104 struct protent ipcp_protent = {
105 PPP_IPCP,
106 ipcp_init,
107 ipcp_input,
108 ipcp_protrej,
109 ipcp_lowerup,
110 ipcp_lowerdown,
111 ipcp_open,
112 ipcp_close,
113 ipcp_printpkt,
114 NULL,
116 "IPCP",
117 ip_check_options,
118 ip_demand_conf,
119 ip_active_pkt
122 static void ipcp_clear_addrs(int);
125 * Lengths of configuration options.
127 #define CILEN_VOID 2
128 #define CILEN_COMPRESS 4 /* min length for compression protocol opt. */
129 #define CILEN_VJ 6 /* length for RFC1332 Van-Jacobson opt. */
130 #define CILEN_ADDR 6 /* new-style single address option */
131 #define CILEN_ADDRS 10 /* old-style dual address option */
134 #define CODENAME(x) ((x) == CONFACK ? "ACK" : \
135 (x) == CONFNAK ? "NAK" : "REJ")
139 * Make a string representation of a network IP address.
141 char *
142 ip_ntoa(u_int32_t ipaddr)
144 static char b[64];
146 ipaddr = ntohl(ipaddr);
148 sprintf(b, "%d.%d.%d.%d",
149 (u_char)(ipaddr >> 24),
150 (u_char)(ipaddr >> 16),
151 (u_char)(ipaddr >> 8),
152 (u_char)(ipaddr));
153 return b;
158 * ipcp_init - Initialize IPCP.
160 static void
161 ipcp_init(int unit)
163 fsm *f = &ipcp_fsm[unit];
164 ipcp_options *wo = &ipcp_wantoptions[unit];
165 ipcp_options *ao = &ipcp_allowoptions[unit];
167 f->unit = unit;
168 f->protocol = PPP_IPCP;
169 f->callbacks = &ipcp_callbacks;
170 fsm_init(&ipcp_fsm[unit]);
172 memset(wo, 0, sizeof(*wo));
173 memset(ao, 0, sizeof(*ao));
175 wo->neg_addr = 1;
176 wo->neg_vj = 1;
177 wo->vj_protocol = IPCP_VJ_COMP;
178 wo->maxslotindex = MAX_STATES - 1; /* really max index */
179 wo->cflag = 1;
181 /* max slots and slot-id compression are currently hardwired in */
182 /* ppp_if.c to 16 and 1, this needs to be changed (among other */
183 /* things) gmc */
185 ao->neg_addr = 1;
186 ao->neg_vj = 1;
187 ao->maxslotindex = MAX_STATES - 1;
188 ao->cflag = 1;
191 * XXX These control whether the user may use the proxyarp
192 * and defaultroute options.
194 ao->proxy_arp = 1;
195 ao->default_route = 1;
200 * ipcp_open - IPCP is allowed to come up.
202 static void
203 ipcp_open(int unit)
205 fsm_open(&ipcp_fsm[unit]);
210 * ipcp_close - Take IPCP down.
212 static void
213 ipcp_close(int unit, char *reason)
215 fsm_close(&ipcp_fsm[unit], reason);
220 * ipcp_lowerup - The lower layer is up.
222 static void
223 ipcp_lowerup(int unit)
225 fsm_lowerup(&ipcp_fsm[unit]);
230 * ipcp_lowerdown - The lower layer is down.
232 static void
233 ipcp_lowerdown(int unit)
235 fsm_lowerdown(&ipcp_fsm[unit]);
240 * ipcp_input - Input IPCP packet.
242 static void
243 ipcp_input(int unit, u_char *p, int len)
245 fsm_input(&ipcp_fsm[unit], p, len);
250 * ipcp_protrej - A Protocol-Reject was received for IPCP.
252 * Pretend the lower layer went down, so we shut up.
254 static void
255 ipcp_protrej(int unit)
257 fsm_lowerdown(&ipcp_fsm[unit]);
262 * ipcp_resetci - Reset our CI.
264 static void
265 ipcp_resetci(fsm *f)
267 ipcp_options *wo = &ipcp_wantoptions[f->unit];
269 wo->req_addr = wo->neg_addr && ipcp_allowoptions[f->unit].neg_addr;
270 if (wo->ouraddr == 0)
271 wo->accept_local = 1;
272 if (wo->hisaddr == 0)
273 wo->accept_remote = 1;
274 ipcp_gotoptions[f->unit] = *wo;
275 cis_received[f->unit] = 0;
280 * ipcp_cilen - Return length of our CI.
282 static int
283 ipcp_cilen(fsm *f)
285 ipcp_options *go = &ipcp_gotoptions[f->unit];
286 ipcp_options *wo = &ipcp_wantoptions[f->unit];
287 ipcp_options *ho = &ipcp_hisoptions[f->unit];
289 #define LENCIVJ(neg, old) (neg ? (old? CILEN_COMPRESS : CILEN_VJ) : 0)
290 #define LENCIADDR(neg, old) (neg ? (old? CILEN_ADDRS : CILEN_ADDR) : 0)
293 * First see if we want to change our options to the old
294 * forms because we have received old forms from the peer.
296 if (wo->neg_addr && !go->neg_addr && !go->old_addrs) {
297 /* use the old style of address negotiation */
298 go->neg_addr = 1;
299 go->old_addrs = 1;
301 if (wo->neg_vj && !go->neg_vj && !go->old_vj) {
302 /* try an older style of VJ negotiation */
303 if (cis_received[f->unit] == 0) {
304 /* keep trying the new style until we see some CI from the peer */
305 go->neg_vj = 1;
306 } else {
307 /* use the old style only if the peer did */
308 if (ho->neg_vj && ho->old_vj) {
309 go->neg_vj = 1;
310 go->old_vj = 1;
311 go->vj_protocol = ho->vj_protocol;
316 return (LENCIADDR(go->neg_addr, go->old_addrs) +
317 LENCIVJ(go->neg_vj, go->old_vj));
322 * ipcp_addci - Add our desired CIs to a packet.
324 static void
325 ipcp_addci(fsm *f, u_char *ucp, int *lenp)
327 ipcp_options *go = &ipcp_gotoptions[f->unit];
328 int len = *lenp;
330 #define ADDCIVJ(opt, neg, val, old, maxslotindex, cflag) \
331 if (neg) { \
332 int vjlen = old? CILEN_COMPRESS : CILEN_VJ; \
333 if (len >= vjlen) { \
334 PUTCHAR(opt, ucp); \
335 PUTCHAR(vjlen, ucp); \
336 PUTSHORT(val, ucp); \
337 if (!old) { \
338 PUTCHAR(maxslotindex, ucp); \
339 PUTCHAR(cflag, ucp); \
341 len -= vjlen; \
342 } else \
343 neg = 0; \
346 #define ADDCIADDR(opt, neg, old, val1, val2) \
347 if (neg) { \
348 int addrlen = (old? CILEN_ADDRS: CILEN_ADDR); \
349 if (len >= addrlen) { \
350 u_int32_t l; \
351 PUTCHAR(opt, ucp); \
352 PUTCHAR(addrlen, ucp); \
353 l = ntohl(val1); \
354 PUTLONG(l, ucp); \
355 if (old) { \
356 l = ntohl(val2); \
357 PUTLONG(l, ucp); \
359 len -= addrlen; \
360 } else \
361 neg = 0; \
364 ADDCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), go->neg_addr,
365 go->old_addrs, go->ouraddr, go->hisaddr);
367 ADDCIVJ(CI_COMPRESSTYPE, go->neg_vj, go->vj_protocol, go->old_vj,
368 go->maxslotindex, go->cflag);
370 *lenp -= len;
375 * ipcp_ackci - Ack our CIs.
377 * Returns:
378 * 0 - Ack was bad.
379 * 1 - Ack was good.
381 static int
382 ipcp_ackci(fsm *f, u_char *p, int len)
384 ipcp_options *go = &ipcp_gotoptions[f->unit];
385 u_short cilen, citype, cishort;
386 u_int32_t cilong;
387 u_char cimaxslotindex, cicflag;
390 * CIs must be in exactly the same order that we sent...
391 * Check packet length and CI length at each step.
392 * If we find any deviations, then this packet is bad.
395 #define ACKCIVJ(opt, neg, val, old, maxslotindex, cflag) \
396 if (neg) { \
397 int vjlen = old? CILEN_COMPRESS : CILEN_VJ; \
398 if ((len -= vjlen) < 0) \
399 goto bad; \
400 GETCHAR(citype, p); \
401 GETCHAR(cilen, p); \
402 if (cilen != vjlen || \
403 citype != opt) \
404 goto bad; \
405 GETSHORT(cishort, p); \
406 if (cishort != val) \
407 goto bad; \
408 if (!old) { \
409 GETCHAR(cimaxslotindex, p); \
410 if (cimaxslotindex != maxslotindex) \
411 goto bad; \
412 GETCHAR(cicflag, p); \
413 if (cicflag != cflag) \
414 goto bad; \
418 #define ACKCIADDR(opt, neg, old, val1, val2) \
419 if (neg) { \
420 int addrlen = (old? CILEN_ADDRS: CILEN_ADDR); \
421 u_int32_t l; \
422 if ((len -= addrlen) < 0) \
423 goto bad; \
424 GETCHAR(citype, p); \
425 GETCHAR(cilen, p); \
426 if (cilen != addrlen || \
427 citype != opt) \
428 goto bad; \
429 GETLONG(l, p); \
430 cilong = htonl(l); \
431 if (val1 != cilong) \
432 goto bad; \
433 if (old) { \
434 GETLONG(l, p); \
435 cilong = htonl(l); \
436 if (val2 != cilong) \
437 goto bad; \
441 ACKCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), go->neg_addr,
442 go->old_addrs, go->ouraddr, go->hisaddr);
444 ACKCIVJ(CI_COMPRESSTYPE, go->neg_vj, go->vj_protocol, go->old_vj,
445 go->maxslotindex, go->cflag);
448 * If there are any remaining CIs, then this packet is bad.
450 if (len != 0)
451 goto bad;
452 return (1);
454 bad:
455 IPCPDEBUG((LOG_INFO, "ipcp_ackci: received bad Ack!"));
456 return (0);
460 * ipcp_nakci - Peer has sent a NAK for some of our CIs.
461 * This should not modify any state if the Nak is bad
462 * or if IPCP is in the OPENED state.
464 * Returns:
465 * 0 - Nak was bad.
466 * 1 - Nak was good.
468 static int
469 ipcp_nakci(fsm *f, u_char *p, int len)
471 ipcp_options *go = &ipcp_gotoptions[f->unit];
472 u_char cimaxslotindex, cicflag;
473 u_char citype, cilen, *next;
474 u_short cishort;
475 u_int32_t ciaddr1, ciaddr2, l;
476 ipcp_options no; /* options we've seen Naks for */
477 ipcp_options try; /* options to request next time */
479 BZERO(&no, sizeof(no));
480 try = *go;
483 * Any Nak'd CIs must be in exactly the same order that we sent.
484 * Check packet length and CI length at each step.
485 * If we find any deviations, then this packet is bad.
487 #define NAKCIADDR(opt, neg, old, code) \
488 if (go->neg && \
489 len >= (cilen = (old? CILEN_ADDRS: CILEN_ADDR)) && \
490 p[1] == cilen && \
491 p[0] == opt) { \
492 len -= cilen; \
493 INCPTR(2, p); \
494 GETLONG(l, p); \
495 ciaddr1 = htonl(l); \
496 if (old) { \
497 GETLONG(l, p); \
498 ciaddr2 = htonl(l); \
499 no.old_addrs = 1; \
500 } else \
501 ciaddr2 = 0; \
502 no.neg = 1; \
503 code \
506 #define NAKCIVJ(opt, neg, code) \
507 if (go->neg && \
508 ((cilen = p[1]) == CILEN_COMPRESS || cilen == CILEN_VJ) && \
509 len >= cilen && \
510 p[0] == opt) { \
511 len -= cilen; \
512 INCPTR(2, p); \
513 GETSHORT(cishort, p); \
514 no.neg = 1; \
515 code \
519 * Accept the peer's idea of {our,his} address, if different
520 * from our idea, only if the accept_{local,remote} flag is set.
522 NAKCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), neg_addr, go->old_addrs,
523 if (go->accept_local && ciaddr1) { /* Do we know our address? */
524 try.ouraddr = ciaddr1;
525 IPCPDEBUG((LOG_INFO, "local IP address %s",
526 ip_ntoa(ciaddr1)));
528 if (go->accept_remote && ciaddr2) { /* Does he know his? */
529 try.hisaddr = ciaddr2;
530 IPCPDEBUG((LOG_INFO, "remote IP address %s",
531 ip_ntoa(ciaddr2)));
536 * Accept the peer's value of maxslotindex provided that it
537 * is less than what we asked for. Turn off slot-ID compression
538 * if the peer wants. Send old-style compress-type option if
539 * the peer wants.
541 NAKCIVJ(CI_COMPRESSTYPE, neg_vj,
542 if (cilen == CILEN_VJ) {
543 GETCHAR(cimaxslotindex, p);
544 GETCHAR(cicflag, p);
545 if (cishort == IPCP_VJ_COMP) {
546 try.old_vj = 0;
547 if (cimaxslotindex < go->maxslotindex)
548 try.maxslotindex = cimaxslotindex;
549 if (!cicflag)
550 try.cflag = 0;
551 } else {
552 try.neg_vj = 0;
554 } else {
555 if (cishort == IPCP_VJ_COMP || cishort == IPCP_VJ_COMP_OLD) {
556 try.old_vj = 1;
557 try.vj_protocol = cishort;
558 } else {
559 try.neg_vj = 0;
565 * There may be remaining CIs, if the peer is requesting negotiation
566 * on an option that we didn't include in our request packet.
567 * If they want to negotiate about IP addresses, we comply.
568 * If they want us to ask for compression, we refuse.
570 while (len > CILEN_VOID) {
571 GETCHAR(citype, p);
572 GETCHAR(cilen, p);
573 if( (len -= cilen) < 0 )
574 goto bad;
575 next = p + cilen - 2;
577 switch (citype) {
578 case CI_COMPRESSTYPE:
579 if (go->neg_vj || no.neg_vj ||
580 (cilen != CILEN_VJ && cilen != CILEN_COMPRESS))
581 goto bad;
582 no.neg_vj = 1;
583 break;
584 case CI_ADDRS:
585 if ((go->neg_addr && go->old_addrs) || no.old_addrs
586 || cilen != CILEN_ADDRS)
587 goto bad;
588 try.neg_addr = 1;
589 try.old_addrs = 1;
590 GETLONG(l, p);
591 ciaddr1 = htonl(l);
592 if (ciaddr1 && go->accept_local)
593 try.ouraddr = ciaddr1;
594 GETLONG(l, p);
595 ciaddr2 = htonl(l);
596 if (ciaddr2 && go->accept_remote)
597 try.hisaddr = ciaddr2;
598 no.old_addrs = 1;
599 break;
600 case CI_ADDR:
601 if (go->neg_addr || no.neg_addr || cilen != CILEN_ADDR)
602 goto bad;
603 try.old_addrs = 0;
604 GETLONG(l, p);
605 ciaddr1 = htonl(l);
606 if (ciaddr1 && go->accept_local)
607 try.ouraddr = ciaddr1;
608 if (try.ouraddr != 0)
609 try.neg_addr = 1;
610 no.neg_addr = 1;
611 break;
613 p = next;
616 /* If there is still anything left, this packet is bad. */
617 if (len != 0)
618 goto bad;
621 * OK, the Nak is good. Now we can update state.
623 if (f->state != OPENED)
624 *go = try;
626 return 1;
628 bad:
629 IPCPDEBUG((LOG_INFO, "ipcp_nakci: received bad Nak!"));
630 return 0;
635 * ipcp_rejci - Reject some of our CIs.
637 static int
638 ipcp_rejci(fsm *f, u_char *p, int len)
640 ipcp_options *go = &ipcp_gotoptions[f->unit];
641 u_char cimaxslotindex, ciflag, cilen;
642 u_short cishort;
643 u_int32_t cilong;
644 ipcp_options try; /* options to request next time */
646 try = *go;
648 * Any Rejected CIs must be in exactly the same order that we sent.
649 * Check packet length and CI length at each step.
650 * If we find any deviations, then this packet is bad.
652 #define REJCIADDR(opt, neg, old, val1, val2) \
653 if (go->neg && \
654 len >= (cilen = old? CILEN_ADDRS: CILEN_ADDR) && \
655 p[1] == cilen && \
656 p[0] == opt) { \
657 u_int32_t l; \
658 len -= cilen; \
659 INCPTR(2, p); \
660 GETLONG(l, p); \
661 cilong = htonl(l); \
662 /* Check rejected value. */ \
663 if (cilong != val1) \
664 goto bad; \
665 if (old) { \
666 GETLONG(l, p); \
667 cilong = htonl(l); \
668 /* Check rejected value. */ \
669 if (cilong != val2) \
670 goto bad; \
672 try.neg = 0; \
675 #define REJCIVJ(opt, neg, val, old, maxslot, cflag) \
676 if (go->neg && \
677 p[1] == (old? CILEN_COMPRESS : CILEN_VJ) && \
678 len >= p[1] && \
679 p[0] == opt) { \
680 len -= p[1]; \
681 INCPTR(2, p); \
682 GETSHORT(cishort, p); \
683 /* Check rejected value. */ \
684 if (cishort != val) \
685 goto bad; \
686 if (!old) { \
687 GETCHAR(cimaxslotindex, p); \
688 if (cimaxslotindex != maxslot) \
689 goto bad; \
690 GETCHAR(ciflag, p); \
691 if (ciflag != cflag) \
692 goto bad; \
694 try.neg = 0; \
697 REJCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), neg_addr,
698 go->old_addrs, go->ouraddr, go->hisaddr);
700 REJCIVJ(CI_COMPRESSTYPE, neg_vj, go->vj_protocol, go->old_vj,
701 go->maxslotindex, go->cflag);
704 * If there are any remaining CIs, then this packet is bad.
706 if (len != 0)
707 goto bad;
709 * Now we can update state.
711 if (f->state != OPENED)
712 *go = try;
713 return 1;
715 bad:
716 IPCPDEBUG((LOG_INFO, "ipcp_rejci: received bad Reject!"));
717 return 0;
722 * ipcp_reqci - Check the peer's requested CIs and send appropriate response.
724 * Returns: CONFACK, CONFNAK or CONFREJ and input packet modified
725 * appropriately. If reject_if_disagree is non-zero, doesn't return
726 * CONFNAK; returns CONFREJ if it can't return CONFACK.
728 * Parameters:
729 * inp: Requested CIs
730 * len: Length of requested CIs
732 static int
733 ipcp_reqci(fsm *f, u_char *inp, int *len, int reject_if_disagree)
735 ipcp_options *wo = &ipcp_wantoptions[f->unit];
736 ipcp_options *ho = &ipcp_hisoptions[f->unit];
737 ipcp_options *ao = &ipcp_allowoptions[f->unit];
738 ipcp_options *go = &ipcp_gotoptions[f->unit];
739 u_char *cip, *next; /* Pointer to current and next CIs */
740 u_short cilen, citype; /* Parsed len, type */
741 u_short cishort; /* Parsed short value */
742 u_int32_t tl, ciaddr1, ciaddr2;/* Parsed address values */
743 int rc = CONFACK; /* Final packet return code */
744 int orc; /* Individual option return code */
745 u_char *p; /* Pointer to next char to parse */
746 u_char *ucp = inp; /* Pointer to current output char */
747 int l = *len; /* Length left */
748 u_char maxslotindex, cflag;
749 int d;
751 cis_received[f->unit] = 1;
754 * Reset all his options.
756 BZERO(ho, sizeof(*ho));
759 * Process all his options.
761 next = inp;
762 while (l) {
763 orc = CONFACK; /* Assume success */
764 cip = p = next; /* Remember begining of CI */
765 if (l < 2 || /* Not enough data for CI header or */
766 p[1] < 2 || /* CI length too small or */
767 p[1] > l) { /* CI length too big? */
768 IPCPDEBUG((LOG_INFO, "ipcp_reqci: bad CI length!"));
769 orc = CONFREJ; /* Reject bad CI */
770 cilen = l; /* Reject till end of packet */
771 l = 0; /* Don't loop again */
772 goto endswitch;
774 GETCHAR(citype, p); /* Parse CI type */
775 GETCHAR(cilen, p); /* Parse CI length */
776 l -= cilen; /* Adjust remaining length */
777 next += cilen; /* Step to next CI */
779 switch (citype) { /* Check CI type */
780 case CI_ADDRS:
781 IPCPDEBUG((LOG_INFO, "ipcp: received ADDRS "));
782 if (!ao->neg_addr ||
783 cilen != CILEN_ADDRS) { /* Check CI length */
784 orc = CONFREJ; /* Reject CI */
785 break;
789 * If he has no address, or if we both have his address but
790 * disagree about it, then NAK it with our idea.
791 * In particular, if we don't know his address, but he does,
792 * then accept it.
794 GETLONG(tl, p); /* Parse source address (his) */
795 ciaddr1 = htonl(tl);
796 IPCPDEBUG((LOG_INFO, "(%s:", ip_ntoa(ciaddr1)));
797 if (ciaddr1 != wo->hisaddr
798 && (ciaddr1 == 0 || !wo->accept_remote)) {
799 orc = CONFNAK;
800 if (!reject_if_disagree) {
801 DECPTR(sizeof(u_int32_t), p);
802 tl = ntohl(wo->hisaddr);
803 PUTLONG(tl, p);
805 } else if (ciaddr1 == 0 && wo->hisaddr == 0) {
807 * If neither we nor he knows his address, reject the option.
809 orc = CONFREJ;
810 wo->req_addr = 0; /* don't NAK with 0.0.0.0 later */
811 break;
815 * If he doesn't know our address, or if we both have our address
816 * but disagree about it, then NAK it with our idea.
818 GETLONG(tl, p); /* Parse desination address (ours) */
819 ciaddr2 = htonl(tl);
820 IPCPDEBUG((LOG_INFO, "%s)", ip_ntoa(ciaddr2)));
821 if (ciaddr2 != wo->ouraddr) {
822 if (ciaddr2 == 0 || !wo->accept_local) {
823 orc = CONFNAK;
824 if (!reject_if_disagree) {
825 DECPTR(sizeof(u_int32_t), p);
826 tl = ntohl(wo->ouraddr);
827 PUTLONG(tl, p);
829 } else {
830 go->ouraddr = ciaddr2; /* accept peer's idea */
834 ho->neg_addr = 1;
835 ho->old_addrs = 1;
836 ho->hisaddr = ciaddr1;
837 ho->ouraddr = ciaddr2;
838 break;
840 case CI_ADDR:
841 IPCPDEBUG((LOG_INFO, "ipcp: received ADDR "));
843 if (!ao->neg_addr ||
844 cilen != CILEN_ADDR) { /* Check CI length */
845 orc = CONFREJ; /* Reject CI */
846 break;
850 * If he has no address, or if we both have his address but
851 * disagree about it, then NAK it with our idea.
852 * In particular, if we don't know his address, but he does,
853 * then accept it.
855 GETLONG(tl, p); /* Parse source address (his) */
856 ciaddr1 = htonl(tl);
857 IPCPDEBUG((LOG_INFO, "(%s)", ip_ntoa(ciaddr1)));
858 if (ciaddr1 != wo->hisaddr
859 && (ciaddr1 == 0 || !wo->accept_remote)) {
860 orc = CONFNAK;
861 if (!reject_if_disagree) {
862 DECPTR(sizeof(u_int32_t), p);
863 tl = ntohl(wo->hisaddr);
864 PUTLONG(tl, p);
866 } else if (ciaddr1 == 0 && wo->hisaddr == 0) {
868 * Don't ACK an address of 0.0.0.0 - reject it instead.
870 orc = CONFREJ;
871 wo->req_addr = 0; /* don't NAK with 0.0.0.0 later */
872 break;
875 ho->neg_addr = 1;
876 ho->hisaddr = ciaddr1;
877 break;
879 case CI_MS_DNS1:
880 case CI_MS_DNS2:
881 /* Microsoft primary or secondary DNS request */
882 d = citype == CI_MS_DNS2;
883 IPCPDEBUG((LOG_INFO, "ipcp: received DNS%d Request ", d+1));
885 /* If we do not have a DNS address then we cannot send it */
886 if (ao->dnsaddr[d] == 0 ||
887 cilen != CILEN_ADDR) { /* Check CI length */
888 orc = CONFREJ; /* Reject CI */
889 break;
891 GETLONG(tl, p);
892 if (htonl(tl) != ao->dnsaddr[d]) {
893 DECPTR(sizeof(u_int32_t), p);
894 tl = ntohl(ao->dnsaddr[d]);
895 PUTLONG(tl, p);
896 orc = CONFNAK;
898 break;
900 case CI_MS_WINS1:
901 case CI_MS_WINS2:
902 /* Microsoft primary or secondary WINS request */
903 d = citype == CI_MS_WINS2;
904 IPCPDEBUG((LOG_INFO, "ipcp: received WINS%d Request ", d+1));
906 /* If we do not have a DNS address then we cannot send it */
907 if (ao->winsaddr[d] == 0 ||
908 cilen != CILEN_ADDR) { /* Check CI length */
909 orc = CONFREJ; /* Reject CI */
910 break;
912 GETLONG(tl, p);
913 if (htonl(tl) != ao->winsaddr[d]) {
914 DECPTR(sizeof(u_int32_t), p);
915 tl = ntohl(ao->winsaddr[d]);
916 PUTLONG(tl, p);
917 orc = CONFNAK;
919 break;
921 case CI_COMPRESSTYPE:
922 IPCPDEBUG((LOG_INFO, "ipcp: received COMPRESSTYPE "));
923 if (!ao->neg_vj ||
924 (cilen != CILEN_VJ && cilen != CILEN_COMPRESS)) {
925 orc = CONFREJ;
926 break;
928 GETSHORT(cishort, p);
929 IPCPDEBUG((LOG_INFO, "(%d)", cishort));
931 if (!(cishort == IPCP_VJ_COMP ||
932 (cishort == IPCP_VJ_COMP_OLD && cilen == CILEN_COMPRESS))) {
933 orc = CONFREJ;
934 break;
937 ho->neg_vj = 1;
938 ho->vj_protocol = cishort;
939 if (cilen == CILEN_VJ) {
940 GETCHAR(maxslotindex, p);
941 if (maxslotindex > ao->maxslotindex) {
942 orc = CONFNAK;
943 if (!reject_if_disagree){
944 DECPTR(1, p);
945 PUTCHAR(ao->maxslotindex, p);
948 GETCHAR(cflag, p);
949 if (cflag && !ao->cflag) {
950 orc = CONFNAK;
951 if (!reject_if_disagree){
952 DECPTR(1, p);
953 PUTCHAR(wo->cflag, p);
956 ho->maxslotindex = maxslotindex;
957 ho->cflag = cflag;
958 } else {
959 ho->old_vj = 1;
960 ho->maxslotindex = MAX_STATES - 1;
961 ho->cflag = 1;
963 break;
965 default:
966 orc = CONFREJ;
967 break;
970 endswitch:
971 IPCPDEBUG((LOG_INFO, " (%s)\n", CODENAME(orc)));
973 if (orc == CONFACK && /* Good CI */
974 rc != CONFACK) /* but prior CI wasnt? */
975 continue; /* Don't send this one */
977 if (orc == CONFNAK) { /* Nak this CI? */
978 if (reject_if_disagree) /* Getting fed up with sending NAKs? */
979 orc = CONFREJ; /* Get tough if so */
980 else {
981 if (rc == CONFREJ) /* Rejecting prior CI? */
982 continue; /* Don't send this one */
983 if (rc == CONFACK) { /* Ack'd all prior CIs? */
984 rc = CONFNAK; /* Not anymore... */
985 ucp = inp; /* Backup */
990 if (orc == CONFREJ && /* Reject this CI */
991 rc != CONFREJ) { /* but no prior ones? */
992 rc = CONFREJ;
993 ucp = inp; /* Backup */
996 /* Need to move CI? */
997 if (ucp != cip)
998 BCOPY(cip, ucp, cilen); /* Move it */
1000 /* Update output pointer */
1001 INCPTR(cilen, ucp);
1005 * If we aren't rejecting this packet, and we want to negotiate
1006 * their address, and they didn't send their address, then we
1007 * send a NAK with a CI_ADDR option appended. We assume the
1008 * input buffer is long enough that we can append the extra
1009 * option safely.
1011 if (rc != CONFREJ && !ho->neg_addr &&
1012 wo->req_addr && !reject_if_disagree) {
1013 if (rc == CONFACK) {
1014 rc = CONFNAK;
1015 ucp = inp; /* reset pointer */
1016 wo->req_addr = 0; /* don't ask again */
1018 PUTCHAR(CI_ADDR, ucp);
1019 PUTCHAR(CILEN_ADDR, ucp);
1020 tl = ntohl(wo->hisaddr);
1021 PUTLONG(tl, ucp);
1024 *len = ucp - inp; /* Compute output length */
1025 IPCPDEBUG((LOG_INFO, "ipcp: returning Configure-%s", CODENAME(rc)));
1026 return (rc); /* Return final code */
1031 * ip_check_options - check that any IP-related options are OK,
1032 * and assign appropriate defaults.
1034 static void
1035 ip_check_options(void)
1037 struct hostent *hp;
1038 u_int32_t local;
1039 ipcp_options *wo = &ipcp_wantoptions[0];
1042 * Default our local IP address based on our hostname.
1043 * If local IP address already given, don't bother.
1045 if (wo->ouraddr == 0 && !disable_defaultip) {
1047 * Look up our hostname (possibly with domain name appended)
1048 * and take the first IP address as our local IP address.
1049 * If there isn't an IP address for our hostname, too bad.
1051 wo->accept_local = 1; /* don't insist on this default value */
1052 if ((hp = gethostbyname(hostname)) != NULL) {
1053 local = *(u_int32_t *)hp->h_addr;
1054 if (local != 0 && !bad_ip_adrs(local))
1055 wo->ouraddr = local;
1059 if (demand && wo->hisaddr == 0) {
1060 option_error("remote IP address required for demand-dialling\n");
1061 exit(1);
1063 #if 0
1064 if (demand && wo->accept_remote) {
1065 option_error("ipcp-accept-remote is incompatible with demand\n");
1066 exit(1);
1068 #endif
1073 * ip_demand_conf - configure the interface as though
1074 * IPCP were up, for use with dial-on-demand.
1076 static int
1077 ip_demand_conf(int u)
1079 ipcp_options *wo = &ipcp_wantoptions[u];
1081 if (!sifaddr(u, wo->ouraddr, wo->hisaddr, GetMask(wo->ouraddr)))
1082 return 0;
1083 if (!sifup(u))
1084 return 0;
1085 if (!sifnpmode(u, PPP_IP, NPMODE_QUEUE))
1086 return 0;
1087 if (wo->default_route)
1088 if (sifdefaultroute(u, wo->ouraddr, wo->hisaddr))
1089 default_route_set[u] = 1;
1090 if (wo->proxy_arp)
1091 if (sifproxyarp(u, wo->hisaddr))
1092 proxy_arp_set[u] = 1;
1094 syslog(LOG_NOTICE, "local IP address %s", ip_ntoa(wo->ouraddr));
1095 syslog(LOG_NOTICE, "remote IP address %s", ip_ntoa(wo->hisaddr));
1097 return 1;
1102 * ipcp_up - IPCP has come UP.
1104 * Configure the IP network interface appropriately and bring it up.
1106 static void
1107 ipcp_up(fsm *f)
1109 u_int32_t mask;
1110 ipcp_options *ho = &ipcp_hisoptions[f->unit];
1111 ipcp_options *go = &ipcp_gotoptions[f->unit];
1112 ipcp_options *wo = &ipcp_wantoptions[f->unit];
1114 np_up(f->unit, PPP_IP);
1115 IPCPDEBUG((LOG_INFO, "ipcp: up"));
1118 * We must have a non-zero IP address for both ends of the link.
1120 if (!ho->neg_addr)
1121 ho->hisaddr = wo->hisaddr;
1123 if (ho->hisaddr == 0) {
1124 syslog(LOG_ERR, "Could not determine remote IP address");
1125 ipcp_close(f->unit, "Could not determine remote IP address");
1126 return;
1128 if (go->ouraddr == 0) {
1129 syslog(LOG_ERR, "Could not determine local IP address");
1130 ipcp_close(f->unit, "Could not determine local IP address");
1131 return;
1133 script_setenv("IPLOCAL", ip_ntoa(go->ouraddr));
1134 script_setenv("IPREMOTE", ip_ntoa(ho->hisaddr));
1137 * Check that the peer is allowed to use the IP address it wants.
1139 if (!auth_ip_addr(f->unit, ho->hisaddr)) {
1140 syslog(LOG_ERR, "Peer is not authorized to use remote address %s",
1141 ip_ntoa(ho->hisaddr));
1142 ipcp_close(f->unit, "Unauthorized remote IP address");
1143 return;
1146 /* set tcp compression */
1147 sifvjcomp(f->unit, ho->neg_vj, ho->cflag, ho->maxslotindex);
1150 * If we are doing dial-on-demand, the interface is already
1151 * configured, so we put out any saved-up packets, then set the
1152 * interface to pass IP packets.
1154 if (demand) {
1155 if (go->ouraddr != wo->ouraddr || ho->hisaddr != wo->hisaddr) {
1156 if (go->ouraddr != wo->ouraddr)
1157 syslog(LOG_WARNING, "Local IP address changed to %s",
1158 ip_ntoa(go->ouraddr));
1159 if (ho->hisaddr != wo->hisaddr)
1160 syslog(LOG_WARNING, "Remote IP address changed to %s",
1161 ip_ntoa(ho->hisaddr));
1162 ipcp_clear_addrs(f->unit);
1164 /* Set the interface to the new addresses */
1165 mask = GetMask(go->ouraddr);
1166 if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask)) {
1167 IPCPDEBUG((LOG_WARNING, "sifaddr failed"));
1168 ipcp_close(f->unit, "Interface configuration failed");
1169 return;
1172 /* assign a default route through the interface if required */
1173 if (ipcp_wantoptions[f->unit].default_route)
1174 if (sifdefaultroute(f->unit, go->ouraddr, ho->hisaddr))
1175 default_route_set[f->unit] = 1;
1177 /* Make a proxy ARP entry if requested. */
1178 if (ipcp_wantoptions[f->unit].proxy_arp)
1179 if (sifproxyarp(f->unit, ho->hisaddr))
1180 proxy_arp_set[f->unit] = 1;
1183 demand_rexmit(PPP_IP);
1184 sifnpmode(f->unit, PPP_IP, NPMODE_PASS);
1186 } else {
1188 * Set IP addresses and (if specified) netmask.
1190 mask = GetMask(go->ouraddr);
1192 #if !(defined(SVR4) && (defined(SNI) || defined(__USLC__)))
1193 if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask)) {
1194 IPCPDEBUG((LOG_WARNING, "sifaddr failed"));
1195 ipcp_close(f->unit, "Interface configuration failed");
1196 return;
1198 #endif
1200 /* bring the interface up for IP */
1201 if (!sifup(f->unit)) {
1202 IPCPDEBUG((LOG_WARNING, "sifup failed"));
1203 ipcp_close(f->unit, "Interface configuration failed");
1204 return;
1207 #if (defined(SVR4) && (defined(SNI) || defined(__USLC__)))
1208 if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask)) {
1209 IPCPDEBUG((LOG_WARNING, "sifaddr failed"));
1210 ipcp_close(f->unit, "Interface configuration failed");
1211 return;
1213 #endif
1214 sifnpmode(f->unit, PPP_IP, NPMODE_PASS);
1216 /* assign a default route through the interface if required */
1217 if (ipcp_wantoptions[f->unit].default_route)
1218 if (sifdefaultroute(f->unit, go->ouraddr, ho->hisaddr))
1219 default_route_set[f->unit] = 1;
1221 /* Make a proxy ARP entry if requested. */
1222 if (ipcp_wantoptions[f->unit].proxy_arp)
1223 if (sifproxyarp(f->unit, ho->hisaddr))
1224 proxy_arp_set[f->unit] = 1;
1226 syslog(LOG_NOTICE, "local IP address %s", ip_ntoa(go->ouraddr));
1227 syslog(LOG_NOTICE, "remote IP address %s", ip_ntoa(ho->hisaddr));
1231 * Execute the ip-up script, like this:
1232 * /etc/ppp/ip-up interface tty speed local-IP remote-IP
1234 ipcp_script(f, _PATH_IPUP);
1240 * ipcp_down - IPCP has gone DOWN.
1242 * Take the IP network interface down, clear its addresses
1243 * and delete routes through it.
1245 static void
1246 ipcp_down(fsm *f)
1248 IPCPDEBUG((LOG_INFO, "ipcp: down"));
1249 np_down(f->unit, PPP_IP);
1250 sifvjcomp(f->unit, 0, 0, 0);
1253 * If we are doing dial-on-demand, set the interface
1254 * to queue up outgoing packets (for now).
1256 if (demand) {
1257 sifnpmode(f->unit, PPP_IP, NPMODE_QUEUE);
1258 } else {
1259 sifdown(f->unit);
1260 ipcp_clear_addrs(f->unit);
1263 /* Execute the ip-down script */
1264 ipcp_script(f, _PATH_IPDOWN);
1269 * ipcp_clear_addrs() - clear the interface addresses, routes,
1270 * proxy arp entries, etc.
1272 static void
1273 ipcp_clear_addrs(int unit)
1275 u_int32_t ouraddr, hisaddr;
1277 ouraddr = ipcp_gotoptions[unit].ouraddr;
1278 hisaddr = ipcp_hisoptions[unit].hisaddr;
1279 if (proxy_arp_set[unit]) {
1280 cifproxyarp(unit, hisaddr);
1281 proxy_arp_set[unit] = 0;
1283 if (default_route_set[unit]) {
1284 cifdefaultroute(unit, ouraddr, hisaddr);
1285 default_route_set[unit] = 0;
1287 cifaddr(unit, ouraddr, hisaddr);
1292 * ipcp_finished - possibly shut down the lower layers.
1294 static void
1295 ipcp_finished(fsm *f)
1297 np_finished(f->unit, PPP_IP);
1302 * ipcp_script - Execute a script with arguments
1303 * interface-name tty-name speed local-IP remote-IP.
1305 static void
1306 ipcp_script(fsm *f, char *script)
1308 char strspeed[32], strlocal[32], strremote[32];
1309 char *argv[8];
1311 sprintf(strspeed, "%d", baud_rate);
1312 strcpy(strlocal, ip_ntoa(ipcp_gotoptions[f->unit].ouraddr));
1313 strcpy(strremote, ip_ntoa(ipcp_hisoptions[f->unit].hisaddr));
1315 argv[0] = script;
1316 argv[1] = ifname;
1317 argv[2] = devnam;
1318 argv[3] = strspeed;
1319 argv[4] = strlocal;
1320 argv[5] = strremote;
1321 argv[6] = ipparam;
1322 argv[7] = NULL;
1323 run_program(script, argv, 0);
1327 * ipcp_printpkt - print the contents of an IPCP packet.
1329 static char *ipcp_codenames[] = {
1330 "ConfReq", "ConfAck", "ConfNak", "ConfRej",
1331 "TermReq", "TermAck", "CodeRej"
1334 static int
1335 ipcp_printpkt(u_char *p, int plen, void (*printer)(void *, char *, ...),
1336 void *arg)
1338 int code, id, len, olen;
1339 u_char *pstart, *optend;
1340 u_short cishort;
1341 u_int32_t cilong;
1343 if (plen < HEADERLEN)
1344 return 0;
1345 pstart = p;
1346 GETCHAR(code, p);
1347 GETCHAR(id, p);
1348 GETSHORT(len, p);
1349 if (len < HEADERLEN || len > plen)
1350 return 0;
1352 if (code >= 1 && code <= sizeof(ipcp_codenames) / sizeof(char *))
1353 printer(arg, " %s", ipcp_codenames[code-1]);
1354 else
1355 printer(arg, " code=0x%x", code);
1356 printer(arg, " id=0x%x", id);
1357 len -= HEADERLEN;
1358 switch (code) {
1359 case CONFREQ:
1360 case CONFACK:
1361 case CONFNAK:
1362 case CONFREJ:
1363 /* print option list */
1364 while (len >= 2) {
1365 GETCHAR(code, p);
1366 GETCHAR(olen, p);
1367 p -= 2;
1368 if (olen < 2 || olen > len) {
1369 break;
1371 printer(arg, " <");
1372 len -= olen;
1373 optend = p + olen;
1374 switch (code) {
1375 case CI_ADDRS:
1376 if (olen == CILEN_ADDRS) {
1377 p += 2;
1378 GETLONG(cilong, p);
1379 printer(arg, "addrs %I", htonl(cilong));
1380 GETLONG(cilong, p);
1381 printer(arg, " %I", htonl(cilong));
1383 break;
1384 case CI_COMPRESSTYPE:
1385 if (olen >= CILEN_COMPRESS) {
1386 p += 2;
1387 GETSHORT(cishort, p);
1388 printer(arg, "compress ");
1389 switch (cishort) {
1390 case IPCP_VJ_COMP:
1391 printer(arg, "VJ");
1392 break;
1393 case IPCP_VJ_COMP_OLD:
1394 printer(arg, "old-VJ");
1395 break;
1396 default:
1397 printer(arg, "0x%x", cishort);
1400 break;
1401 case CI_ADDR:
1402 if (olen == CILEN_ADDR) {
1403 p += 2;
1404 GETLONG(cilong, p);
1405 printer(arg, "addr %I", htonl(cilong));
1407 break;
1408 case CI_MS_DNS1:
1409 case CI_MS_DNS2:
1410 p += 2;
1411 GETLONG(cilong, p);
1412 printer(arg, "ms-dns %I", htonl(cilong));
1413 break;
1414 case CI_MS_WINS1:
1415 case CI_MS_WINS2:
1416 p += 2;
1417 GETLONG(cilong, p);
1418 printer(arg, "ms-wins %I", htonl(cilong));
1419 break;
1421 while (p < optend) {
1422 GETCHAR(code, p);
1423 printer(arg, " %.2x", code);
1425 printer(arg, ">");
1427 break;
1429 case TERMACK:
1430 case TERMREQ:
1431 if (len > 0 && *p >= ' ' && *p < 0x7f) {
1432 printer(arg, " ");
1433 print_string(p, len, printer, arg);
1434 p += len;
1435 len = 0;
1437 break;
1440 /* print the rest of the bytes in the packet */
1441 for (; len > 0; --len) {
1442 GETCHAR(code, p);
1443 printer(arg, " %.2x", code);
1446 return p - pstart;
1450 * ip_active_pkt - see if this IP packet is worth bringing the link up for.
1451 * We don't bring the link up for IP fragments or for TCP FIN packets
1452 * with no data.
1454 #define IP_HDRLEN 20 /* bytes */
1455 #define IP_OFFMASK 0x1fff
1456 #define IPPROTO_TCP 6
1457 #define TCP_HDRLEN 20
1458 #define TH_FIN 0x01
1461 * We use these macros because the IP header may be at an odd address,
1462 * and some compilers might use word loads to get th_off or ip_hl.
1465 #define net_short(x) (((x)[0] << 8) + (x)[1])
1466 #define get_iphl(x) (((unsigned char *)(x))[0] & 0xF)
1467 #define get_ipoff(x) net_short((unsigned char *)(x) + 6)
1468 #define get_ipproto(x) (((unsigned char *)(x))[9])
1469 #define get_tcpoff(x) (((unsigned char *)(x))[12] >> 4)
1470 #define get_tcpflags(x) (((unsigned char *)(x))[13])
1472 static int
1473 ip_active_pkt(u_char *pkt, int len)
1475 u_char *tcp;
1476 int hlen;
1478 len -= PPP_HDRLEN;
1479 pkt += PPP_HDRLEN;
1480 if (len < IP_HDRLEN)
1481 return 0;
1482 if ((get_ipoff(pkt) & IP_OFFMASK) != 0)
1483 return 0;
1484 if (get_ipproto(pkt) != IPPROTO_TCP)
1485 return 1;
1486 hlen = get_iphl(pkt) * 4;
1487 if (len < hlen + TCP_HDRLEN)
1488 return 0;
1489 tcp = pkt + hlen;
1490 if ((get_tcpflags(tcp) & TH_FIN) != 0 && len == hlen + get_tcpoff(tcp) * 4)
1491 return 0;
1492 return 1;