xref: /illumos-gate/usr/src/cmd/cmd-inet/usr.bin/pppd/ipcp.c (revision 2b987d42b0ad07d74e39b18a2498709e5195d7e3)
1 /*
2  * ipcp.c - PPP IP Control Protocol.
3  *
4  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
5  * Use is subject to license terms.
6  *
7  * Copyright (c) 1989 Carnegie Mellon University.
8  * All rights reserved.
9  *
10  * Redistribution and use in source and binary forms are permitted
11  * provided that the above copyright notice and this paragraph are
12  * duplicated in all such forms and that any documentation,
13  * advertising materials, and other materials related to such
14  * distribution and use acknowledge that the software was developed
15  * by Carnegie Mellon University.  The name of the
16  * University may not be used to endorse or promote products derived
17  * from this software without specific prior written permission.
18  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
20  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
21  */
22 /*
23  * Copyright (c) 2016 by Delphix. All rights reserved.
24  */
25 
26 #include <stdio.h>
27 #include <string.h>
28 #include <netdb.h>
29 #include <sys/param.h>
30 #include <sys/types.h>
31 #include <sys/socket.h>
32 #if defined(_linux_) || defined(__linux__)
33 #define	__FAVOR_BSD
34 #endif
35 #include <netinet/in.h>
36 #include <netinet/tcp.h>
37 #include <arpa/inet.h>
38 
39 #include "pppd.h"
40 #include "fsm.h"
41 #include "ipcp.h"
42 #include "pathnames.h"
43 
44 /* global vars */
45 ipcp_options ipcp_wantoptions[NUM_PPP];	/* Options that we want to request */
46 ipcp_options ipcp_gotoptions[NUM_PPP];	/* Options that peer ack'd */
47 ipcp_options ipcp_allowoptions[NUM_PPP]; /* Options we allow peer to request */
48 ipcp_options ipcp_hisoptions[NUM_PPP];	/* Options that we ack'd */
49 
50 bool	ipcp_from_hostname = 0;	/* Local IP address is from hostname lookup */
51 
52 /* Hook for a plugin to know when IP protocol has come up */
53 void (*ip_up_hook) __P((void)) = NULL;
54 
55 /* Hook for a plugin to know when IP protocol has come down */
56 void (*ip_down_hook) __P((void)) = NULL;
57 
58 /* local vars */
59 static bool default_route_set[NUM_PPP];	/* Have set up a default route */
60 static bool proxy_arp_set[NUM_PPP];	/* Have created proxy arp entry */
61 static bool ipcp_is_up[NUM_PPP];	/* have called np_up() */
62 static bool proxy_arp_quiet[NUM_PPP];	/* We should be quiet on error */
63 static bool disable_defaultip = 0;	/* Don't use hostname for IP addr */
64 
65 /*
66  * Callbacks for fsm code.  (CI = Configuration Information)
67  */
68 static void ipcp_resetci __P((fsm *));	/* Reset our CI */
69 static int  ipcp_cilen __P((fsm *));	        /* Return length of our CI */
70 static void ipcp_addci __P((fsm *, u_char *, int *)); /* Add our CI */
71 static int  ipcp_ackci __P((fsm *, u_char *, int));	/* Peer ack'd our CI */
72 static int  ipcp_nakci __P((fsm *, u_char *, int));	/* Peer nak'd our CI */
73 static int  ipcp_rejci __P((fsm *, u_char *, int));	/* Peer rej'd our CI */
74 static int  ipcp_reqci __P((fsm *, u_char *, int *, int)); /* Rcv CI */
75 static void ipcp_up __P((fsm *));		/* We're UP */
76 static void ipcp_down __P((fsm *));		/* We're DOWN */
77 static void ipcp_finished __P((fsm *));	/* Don't need lower layer */
78 static int  setmsservaddr __P((char *, u_int32_t *));
79 
80 fsm ipcp_fsm[NUM_PPP];		/* IPCP fsm structure */
81 
82 static fsm_callbacks ipcp_callbacks = { /* IPCP callback routines */
83     ipcp_resetci,		/* Reset our Configuration Information */
84     ipcp_cilen,			/* Length of our Configuration Information */
85     ipcp_addci,			/* Add our Configuration Information */
86     ipcp_ackci,			/* ACK our Configuration Information */
87     ipcp_nakci,			/* NAK our Configuration Information */
88     ipcp_rejci,			/* Reject our Configuration Information */
89     ipcp_reqci,			/* Request peer's Configuration Information */
90     ipcp_up,			/* Called when fsm reaches OPENED state */
91     ipcp_down,			/* Called when fsm leaves OPENED state */
92     NULL,			/* Called when we want the lower layer up */
93     ipcp_finished,		/* Called when we want the lower layer down */
94     NULL,			/* Retransmission is necessary */
95     NULL,			/* Called to handle protocol-specific codes */
96     "IPCP",			/* String name of protocol */
97     NULL			/* Peer rejected a code number */
98 };
99 
100 /*
101  * Command-line options.
102  */
103 static int setvjslots __P((char **));
104 static int setdnsaddr __P((char **));
105 static int setwinsaddr __P((char **));
106 static int autoproxyarp __P((char **));
107 
108 static option_t ipcp_option_list[] = {
109     { "noip", o_bool, &ipcp_protent.enabled_flag,
110       "Disable IP and IPCP" },
111     { "-ip", o_bool, &ipcp_protent.enabled_flag,
112       "Disable IP and IPCP" },
113     { "novj", o_bool, &ipcp_wantoptions[0].neg_vj,
114       "Disable VJ compression", OPT_A2COPY, &ipcp_allowoptions[0].neg_vj },
115     { "-vj", o_bool, &ipcp_wantoptions[0].neg_vj,
116       "Disable VJ compression", OPT_A2COPY, &ipcp_allowoptions[0].neg_vj },
117     { "novjccomp", o_bool, &ipcp_wantoptions[0].cflag,
118       "Disable VJ connection-ID compression", OPT_A2COPY,
119       &ipcp_allowoptions[0].cflag },
120     { "-vjccomp", o_bool, &ipcp_wantoptions[0].cflag,
121       "Disable VJ connection-ID compression", OPT_A2COPY,
122       &ipcp_allowoptions[0].cflag },
123     { "vj-max-slots", o_special, (void *)setvjslots,
124       "Set maximum VJ header slots" },
125     { "ipcp-accept-local", o_bool, &ipcp_wantoptions[0].accept_local,
126       "Accept peer's address for us", 1 },
127     { "ipcp-accept-remote", o_bool, &ipcp_wantoptions[0].accept_remote,
128       "Accept peer's address for it", 1 },
129     { "ipparam", o_string, &ipparam,
130       "Set ip script parameter" },
131     { "noipdefault", o_bool, &disable_defaultip,
132       "Don't use name for default IP adrs", 1 },
133     { "ms-dns", o_special, (void *)setdnsaddr,
134       "DNS address for the peer's use" },
135     { "ms-wins", o_special, (void *)setwinsaddr,
136       "Nameserver for SMB over TCP/IP for peer" },
137     { "ipcp-restart", o_int, &ipcp_fsm[0].timeouttime,
138       "Set timeout for IPCP" },
139     { "ipcp-max-terminate", o_int, &ipcp_fsm[0].maxtermtransmits,
140       "Set max #xmits for term-reqs" },
141     { "ipcp-max-configure", o_int, &ipcp_fsm[0].maxconfreqtransmits,
142       "Set max #xmits for conf-reqs" },
143     { "ipcp-max-failure", o_int, &ipcp_fsm[0].maxnakloops,
144       "Set max #conf-naks for IPCP" },
145     { "defaultroute", o_bool, &ipcp_wantoptions[0].default_route,
146       "Add default route", OPT_ENABLE|1, &ipcp_allowoptions[0].default_route },
147     { "nodefaultroute", o_bool, &ipcp_allowoptions[0].default_route,
148       "disable defaultroute option", OPT_A2COPY,
149       &ipcp_wantoptions[0].default_route },
150     { "-defaultroute", o_bool, &ipcp_allowoptions[0].default_route,
151       "disable defaultroute option", OPT_A2COPY,
152       &ipcp_wantoptions[0].default_route },
153     { "proxyarp", o_bool, &ipcp_wantoptions[0].proxy_arp,
154       "Add proxy ARP entry", OPT_ENABLE|1, &ipcp_allowoptions[0].proxy_arp },
155     { "autoproxyarp", o_special_noarg, (void *)autoproxyarp,
156       "Add proxy ARP entry if needed", OPT_ENABLE,
157       &ipcp_allowoptions[0].proxy_arp },
158     { "noproxyarp", o_bool, &ipcp_allowoptions[0].proxy_arp,
159       "disable proxyarp option", OPT_A2COPY, &ipcp_wantoptions[0].proxy_arp },
160     { "-proxyarp", o_bool, &ipcp_allowoptions[0].proxy_arp,
161       "disable proxyarp option", OPT_A2COPY, &ipcp_wantoptions[0].proxy_arp },
162     { "usepeerdns", o_bool, &ipcp_wantoptions[0].req_dns1,
163       "Ask peer for DNS address(es)", OPT_A2COPY|1,
164       &ipcp_wantoptions[0].req_dns2 },
165     { NULL }
166 };
167 
168 /*
169  * Protocol entry points from main code.
170  */
171 static void ipcp_init __P((int));
172 static void ipcp_open __P((int));
173 static void ipcp_close __P((int, char *));
174 static void ipcp_lowerup __P((int));
175 static void ipcp_lowerdown __P((int));
176 static void ipcp_input __P((int, u_char *, int));
177 static void ipcp_protrej __P((int));
178 static int  ipcp_printpkt __P((u_char *, int,
179     void (*) __P((void *, const char *, ...)), void *));
180 static void ip_check_options __P((void));
181 static int  ip_demand_conf __P((int));
182 static int  ip_active_pkt __P((u_char *, int));
183 static void ipcp_print_stat __P((int, FILE *));
184 
185 static void create_resolv __P((u_int32_t, u_int32_t));
186 
187 struct protent ipcp_protent = {
188     PPP_IPCP,
189     ipcp_init,
190     ipcp_input,
191     ipcp_protrej,
192     ipcp_lowerup,
193     ipcp_lowerdown,
194     ipcp_open,
195     ipcp_close,
196     ipcp_printpkt,
197     NULL,
198     1,
199     "IPCP",
200     "IP",
201     ipcp_option_list,
202     ip_check_options,
203     ip_demand_conf,
204     ip_active_pkt,
205     ipcp_print_stat
206 };
207 
208 static void ipcp_clear_addrs __P((int, u_int32_t, u_int32_t));
209 static void ipcp_script __P((char *));		/* Run an up/down script */
210 static void ipcp_script_done __P((void *, int));
211 
212 /*
213  * Lengths of configuration options.
214  */
215 #define CILEN_VOID	2
216 #define CILEN_COMPRESS	4	/* min length for compression protocol opt. */
217 #define CILEN_VJ	6	/* length for RFC1332 Van-Jacobson opt. */
218 #define CILEN_ADDR	6	/* new-style single address option */
219 #define CILEN_ADDRS	10	/* old-style dual address option */
220 
221 
222 /*
223  * This state variable is used to ensure that we don't
224  * run an ipcp-up/down script while one is already running.
225  */
226 static enum script_state {
227     s_down,
228     s_up
229 } ipcp_script_state;
230 static pid_t ipcp_script_pid;
231 
232 /*
233  * Make a string representation of a network IP address.
234  */
235 char *
236 ip_ntoa(ipaddr)
237 u_int32_t ipaddr;
238 {
239     static char b[64];
240 
241     (void) slprintf(b, sizeof(b), "%I", ipaddr);
242     return b;
243 }
244 
245 /*
246  * Option parsing.
247  */
248 
249 /*
250  * setvjslots - set maximum number of connection slots for VJ compression
251  */
252 static int
253 setvjslots(argv)
254     char **argv;
255 {
256     int value;
257 
258     if (!int_option(*argv, &value))
259 	return 0;
260     if (value < 2 || value > 16) {
261 	option_error("vj-max-slots value must be between 2 and 16");
262 	return 0;
263     }
264     ipcp_wantoptions [0].maxslotindex =
265         ipcp_allowoptions[0].maxslotindex = value - 1;
266     return 1;
267 }
268 
269 /*
270  * setmsservaddr - Set the primary and secondary server addresses in the
271  * array.  setdnsaddr() and setwinsaddr() call this function with either
272  * dnsaddr[] or winsaddr[] as the serverarray argument.
273  */
274 static int
275 setmsservaddr(servname, serverarray)
276     char *servname;
277     u_int32_t *serverarray;
278 {
279     u_int32_t addr;
280     struct hostent *hp = NULL;
281 
282     addr = inet_addr(servname);
283     if (addr == (u_int32_t) -1) {
284 	if ((hp = gethostbyname(servname)) == NULL)
285 	    return 0;
286 	BCOPY(hp->h_addr, &addr, sizeof (u_int32_t));
287     }
288 
289     /*
290      * If there is no primary then this is the first instance of the
291      * option, we must set the primary.  In that case, try to set the
292      * secondary to h_addr_list[1].  If the primary is already set, then
293      * this is the second instance of the option, and we must set
294      * the secondary.
295      */
296     if (serverarray[0] == 0) {
297 	serverarray[0] = addr;
298 	if (hp != NULL && hp->h_addr_list[1] != NULL)
299 	    BCOPY(hp->h_addr_list[1], &serverarray[1], sizeof (u_int32_t));
300 	else
301 	    serverarray[1] = addr;
302     } else {
303 	serverarray[1] = addr;
304     }
305 
306     return (1);
307 }
308 
309 /*
310  * setdnsaddr - set the dns address(es)
311  */
312 static int
313 setdnsaddr(argv)
314     char **argv;
315 {
316     if (setmsservaddr(*argv, &(ipcp_allowoptions[0].dnsaddr[0])) == 0) {
317 	option_error("invalid address parameter '%s' for ms-dns option", *argv);
318 	return (0);
319     }
320 
321     return (1);
322 }
323 
324 /*
325  * setwinsaddr - set the wins address(es)
326  * This is primrarly used with the Samba package under UNIX or for pointing
327  * the caller to the existing WINS server on a Windows NT platform.
328  */
329 static int
330 setwinsaddr(argv)
331     char **argv;
332 {
333     if (setmsservaddr(*argv, &(ipcp_allowoptions[0].winsaddr[0])) == 0) {
334 	option_error("invalid address parameter '%s' for ms-wins option",
335 	    *argv);
336 	return (0);
337     }
338 
339     return (1);
340 }
341 
342 /*
343  * autoproxyarp -- enable proxy ARP but don't emit error messages if
344  * it's not actually needed.
345  */
346 /*ARGSUSED*/
347 static int
348 autoproxyarp(argv)
349     char **argv;
350 {
351     ipcp_wantoptions[0].proxy_arp = 1;
352     proxy_arp_quiet[0] = 1;
353 
354     return (1);
355 }
356 
357 
358 /*
359  * ipcp_init - Initialize IPCP.
360  */
361 static void
362 ipcp_init(unit)
363     int unit;
364 {
365     fsm *f = &ipcp_fsm[unit];
366     ipcp_options *wo = &ipcp_wantoptions[unit];
367     ipcp_options *ao = &ipcp_allowoptions[unit];
368 
369     f->unit = unit;
370     f->protocol = PPP_IPCP;
371     f->callbacks = &ipcp_callbacks;
372     fsm_init(&ipcp_fsm[unit]);
373 
374     BZERO(wo, sizeof(*wo));
375     BZERO(ao, sizeof(*ao));
376 
377     wo->neg_addr = wo->old_addrs = 1;
378     wo->neg_vj = 1;
379     wo->vj_protocol = IPCP_VJ_COMP;
380     wo->maxslotindex = MAX_STATES - 1; /* really max index */
381     wo->cflag = 1;
382 
383     ao->neg_addr = ao->old_addrs = 1;
384     ao->neg_vj = 1;
385     ao->maxslotindex = MAX_STATES - 1;
386     ao->cflag = 1;
387 
388     /*
389      * These aren't actually negotiated.  Instead, they control
390      * whether the user may use the proxyarp and defaultroute options.
391      */
392     ao->proxy_arp = 1;
393     ao->default_route = 1;
394     proxy_arp_quiet[unit] = 0;
395 }
396 
397 
398 /*
399  * ipcp_open - IPCP is allowed to come up.
400  */
401 static void
402 ipcp_open(unit)
403     int unit;
404 {
405     fsm_open(&ipcp_fsm[unit]);
406 }
407 
408 
409 /*
410  * ipcp_close - Take IPCP down.
411  */
412 static void
413 ipcp_close(unit, reason)
414     int unit;
415     char *reason;
416 {
417     fsm_close(&ipcp_fsm[unit], reason);
418 }
419 
420 
421 /*
422  * ipcp_lowerup - The lower layer is up.
423  */
424 static void
425 ipcp_lowerup(unit)
426     int unit;
427 {
428     fsm_lowerup(&ipcp_fsm[unit]);
429 }
430 
431 
432 /*
433  * ipcp_lowerdown - The lower layer is down.
434  */
435 static void
436 ipcp_lowerdown(unit)
437     int unit;
438 {
439     fsm_lowerdown(&ipcp_fsm[unit]);
440 }
441 
442 
443 /*
444  * ipcp_input - Input IPCP packet.
445  */
446 static void
447 ipcp_input(unit, p, len)
448     int unit;
449     u_char *p;
450     int len;
451 {
452     fsm_input(&ipcp_fsm[unit], p, len);
453 }
454 
455 
456 /*
457  * ipcp_protrej - A Protocol-Reject was received for IPCP.
458  */
459 static void
460 ipcp_protrej(unit)
461     int unit;
462 {
463     fsm_protreject(&ipcp_fsm[unit]);
464 }
465 
466 
467 /*
468  * ipcp_resetci - Reset our CI.
469  * Called by fsm_sconfreq, Send Configure Request.
470  */
471 static void
472 ipcp_resetci(f)
473     fsm *f;
474 {
475     ipcp_options *wo = &ipcp_wantoptions[f->unit];
476     ipcp_options *go = &ipcp_gotoptions[f->unit];
477     ipcp_options *ao = &ipcp_allowoptions[f->unit];
478 
479     wo->req_addr = (wo->neg_addr || wo->old_addrs) &&
480 	(ao->neg_addr || ao->old_addrs);
481     if (wo->ouraddr == 0 || disable_defaultip)
482 	wo->accept_local = 1;
483     if (wo->hisaddr == 0)
484 	wo->accept_remote = 1;
485     *go = *wo;
486     if (disable_defaultip)
487 	go->ouraddr = 0;
488 }
489 
490 
491 /*
492  * ipcp_cilen - Return length of our CI.
493  * Called by fsm_sconfreq, Send Configure Request.
494  */
495 static int
496 ipcp_cilen(f)
497     fsm *f;
498 {
499     ipcp_options *go = &ipcp_gotoptions[f->unit];
500     ipcp_options *wo = &ipcp_wantoptions[f->unit];
501     ipcp_options *ho = &ipcp_hisoptions[f->unit];
502 
503 #define LENCIADDRS(neg)		(neg ? CILEN_ADDRS : 0)
504 #define LENCIVJ(neg, old)	(neg ? (old? CILEN_COMPRESS : CILEN_VJ) : 0)
505 #define LENCIADDR(neg)		(neg ? (CILEN_ADDR) : 0)
506 
507     /*
508      * First see if we want to change our options to the old
509      * forms because we have received old forms from the peer.
510      */
511     if (go->neg_addr && go->old_addrs && !ho->neg_addr && ho->old_addrs)
512 	/* use the old style of address negotiation */
513 	go->neg_addr = 0;
514     if (wo->neg_vj && !go->neg_vj && !go->old_vj) {
515 	/* try an older style of VJ negotiation */
516 	/* use the old style only if the peer did */
517 	if (ho->neg_vj && ho->old_vj) {
518 	    go->neg_vj = 1;
519 	    go->old_vj = 1;
520 	    go->vj_protocol = ho->vj_protocol;
521 	}
522     }
523 
524     return (LENCIADDRS(!go->neg_addr && go->old_addrs) +
525 	    LENCIVJ(go->neg_vj, go->old_vj) +
526 	    LENCIADDR(go->neg_addr) +
527 	    LENCIADDR(go->req_dns1) +
528 	    LENCIADDR(go->req_dns2)) ;
529 }
530 
531 
532 /*
533  * ipcp_addci - Add our desired CIs to a packet.
534  * Called by fsm_sconfreq, Send Configure Request.
535  */
536 static void
537 ipcp_addci(f, ucp, lenp)
538     fsm *f;
539     u_char *ucp;
540     int *lenp;
541 {
542     ipcp_options *go = &ipcp_gotoptions[f->unit];
543     int len = *lenp;
544 
545 #define ADDCIADDRS(opt, neg, val1, val2) \
546     if (neg) { \
547 	if (len >= CILEN_ADDRS) { \
548 	    PUTCHAR(opt, ucp); \
549 	    PUTCHAR(CILEN_ADDRS, ucp); \
550 	    PUTNLONG(val1, ucp); \
551 	    PUTNLONG(val2, ucp); \
552 	    len -= CILEN_ADDRS; \
553 	} else \
554 	    go->old_addrs = 0; \
555     }
556 
557 #define ADDCIVJ(opt, neg, val, old, maxslotindex, cflag) \
558     if (neg) { \
559 	int vjlen = old? CILEN_COMPRESS : CILEN_VJ; \
560 	if (len >= vjlen) { \
561 	    PUTCHAR(opt, ucp); \
562 	    PUTCHAR(vjlen, ucp); \
563 	    PUTSHORT(val, ucp); \
564 	    if (!old) { \
565 		PUTCHAR(maxslotindex, ucp); \
566 		PUTCHAR(cflag, ucp); \
567 	    } \
568 	    len -= vjlen; \
569 	} else \
570 	    neg = 0; \
571     }
572 
573 #define ADDCIADDR(opt, neg, val) \
574     if (neg) { \
575 	if (len >= CILEN_ADDR) { \
576 	    PUTCHAR(opt, ucp); \
577 	    PUTCHAR(CILEN_ADDR, ucp); \
578 	    PUTNLONG(val, ucp); \
579 	    len -= CILEN_ADDR; \
580 	} else \
581 	    neg = 0; \
582     }
583 
584     ADDCIADDRS(CI_ADDRS, !go->neg_addr && go->old_addrs, go->ouraddr,
585 	       go->hisaddr);
586 
587     ADDCIVJ(CI_COMPRESSTYPE, go->neg_vj, go->vj_protocol, go->old_vj,
588 	    go->maxslotindex, go->cflag);
589 
590     ADDCIADDR(CI_ADDR, go->neg_addr, go->ouraddr);
591 
592     ADDCIADDR(CI_MS_DNS1, go->req_dns1, go->dnsaddr[0]);
593 
594     ADDCIADDR(CI_MS_DNS2, go->req_dns2, go->dnsaddr[1]);
595 
596     *lenp -= len;
597 }
598 
599 
600 /*
601  * ipcp_ackci - Ack our CIs.
602  * Called by fsm_rconfack, Receive Configure ACK.
603  *
604  * Returns:
605  *	0 - Ack was bad.
606  *	1 - Ack was good.
607  */
608 static int
609 ipcp_ackci(f, p, len)
610     fsm *f;
611     u_char *p;
612     int len;
613 {
614     ipcp_options *go = &ipcp_gotoptions[f->unit];
615     u_short cilen, citype, cishort;
616     u_int32_t cilong;
617     u_char cimaxslotindex, cicflag;
618 
619     /*
620      * CIs must be in exactly the same order that we sent...
621      * Check packet length and CI length at each step.
622      * If we find any deviations, then this packet is bad.
623      */
624 
625 #define	ACKCHECK(opt, olen) \
626 	if ((len -= olen) < 0) \
627 	    goto bad; \
628 	GETCHAR(citype, p); \
629 	GETCHAR(cilen, p); \
630 	if (cilen != olen || \
631 	    citype != opt) \
632 	    goto bad;
633 
634 #define ACKCIADDRS(opt, neg, val1, val2) \
635     if (neg) { \
636 	ACKCHECK(opt, CILEN_ADDRS) \
637 	GETNLONG(cilong, p); \
638 	if (val1 != cilong) \
639 	    goto bad; \
640 	GETNLONG(cilong, p); \
641 	if (val2 != cilong) \
642 	    goto bad; \
643     }
644 
645 #define ACKCIVJ(opt, neg, val, old, maxslotindex, cflag) \
646     if (neg) { \
647 	int vjlen = old? CILEN_COMPRESS : CILEN_VJ; \
648 	ACKCHECK(opt, vjlen) \
649 	GETSHORT(cishort, p); \
650 	if (cishort != val) \
651 	    goto bad; \
652 	if (!old) { \
653 	    GETCHAR(cimaxslotindex, p); \
654 	    if (cimaxslotindex != maxslotindex) \
655 		goto bad; \
656 	    GETCHAR(cicflag, p); \
657 	    if (cicflag != cflag) \
658 		goto bad; \
659 	} \
660     }
661 
662 #define ACKCIADDR(opt, neg, val) \
663     if (neg) { \
664 	ACKCHECK(opt, CILEN_ADDR) \
665 	GETNLONG(cilong, p); \
666 	if (val != cilong) \
667 	    goto bad; \
668     }
669 
670     ACKCIADDRS(CI_ADDRS, !go->neg_addr && go->old_addrs, go->ouraddr,
671 	       go->hisaddr);
672 
673     ACKCIVJ(CI_COMPRESSTYPE, go->neg_vj, go->vj_protocol, go->old_vj,
674 	    go->maxslotindex, go->cflag);
675 
676     ACKCIADDR(CI_ADDR, go->neg_addr, go->ouraddr);
677 
678     ACKCIADDR(CI_MS_DNS1, go->req_dns1, go->dnsaddr[0]);
679 
680     ACKCIADDR(CI_MS_DNS2, go->req_dns2, go->dnsaddr[1]);
681 
682     /*
683      * If there are any remaining CIs, then this packet is bad.
684      */
685     if (len != 0)
686 	goto bad;
687     return (1);
688 
689 bad:
690     IPCPDEBUG(("ipcp_ackci: received bad Ack!"));
691     return (0);
692 }
693 
694 /*
695  * ipcp_nakci - Peer has sent a NAK for some of our CIs.
696  * This should not modify any state if the Nak is bad
697  * or if IPCP is in the OPENED state.
698  * Calback from fsm_rconfnakrej - Receive Configure-Nak or Configure-Reject.
699  *
700  * Returns:
701  *	0 - Nak was bad.
702  *	1 - Nak was good.
703  */
704 static int
705 ipcp_nakci(f, p, len)
706     fsm *f;
707     u_char *p;
708     int len;
709 {
710     ipcp_options *go = &ipcp_gotoptions[f->unit];
711     u_char cimaxslotindex, cicflag;
712     u_char citype, cilen, *next;
713     u_short cishort;
714     u_int32_t ciaddr1, ciaddr2;
715     ipcp_options no;		/* options we've seen Naks for */
716     ipcp_options try;		/* options to request next time */
717 
718     BZERO(&no, sizeof(no));
719     try = *go;
720 
721     /*
722      * Any Nak'd CIs must be in exactly the same order that we sent.
723      * Check packet length and CI length at each step.
724      * If we find any deviations, then this packet is bad.
725      */
726 #define NAKCIADDRS(opt, neg, code) \
727     if ((neg) && \
728 	(cilen = p[1]) == CILEN_ADDRS && \
729 	len >= cilen && \
730 	p[0] == opt) { \
731 	len -= cilen; \
732 	INCPTR(2, p); \
733 	GETNLONG(ciaddr1, p); \
734 	GETNLONG(ciaddr2, p); \
735 	no.old_addrs = 1; \
736 	code \
737     }
738 
739 #define NAKCIVJ(opt, neg, code) \
740     if (go->neg && \
741 	((cilen = p[1]) == CILEN_COMPRESS || cilen == CILEN_VJ) && \
742 	len >= cilen && \
743 	p[0] == opt) { \
744 	len -= cilen; \
745 	INCPTR(2, p); \
746 	GETSHORT(cishort, p); \
747 	no.neg = 1; \
748         code \
749     }
750 
751 #define NAKCIADDR(opt, neg, code) \
752     if (go->neg && \
753 	(cilen = p[1]) == CILEN_ADDR && \
754 	len >= cilen && \
755 	p[0] == opt) { \
756 	len -= cilen; \
757 	INCPTR(2, p); \
758 	GETNLONG(ciaddr1, p); \
759 	no.neg = 1; \
760 	code \
761     }
762 
763     /*
764      * Accept the peer's idea of {our,its} address, if different
765      * from our idea, only if the accept_{local,remote} flag is set.
766      */
767     NAKCIADDRS(CI_ADDRS, !go->neg_addr && go->old_addrs,
768 	      if (go->accept_local && ciaddr1) { /* Do we know our address? */
769 		  try.ouraddr = ciaddr1;
770 	      }
771 	      if (go->accept_remote && ciaddr2) { /* Does it know its? */
772 		  try.hisaddr = ciaddr2;
773 	      }
774 	      );
775 
776     /*
777      * Accept the peer's value of maxslotindex provided that it
778      * is less than what we asked for.  Turn off slot-ID compression
779      * if the peer wants.  Send old-style compress-type option if
780      * the peer wants.
781      */
782     NAKCIVJ(CI_COMPRESSTYPE, neg_vj,
783 	    if (cilen == CILEN_VJ) {
784 		GETCHAR(cimaxslotindex, p);
785 		GETCHAR(cicflag, p);
786 		if (cishort == IPCP_VJ_COMP) {
787 		    try.old_vj = 0;
788 		    if (cimaxslotindex < go->maxslotindex)
789 			try.maxslotindex = cimaxslotindex;
790 		    if (!cicflag)
791 			try.cflag = 0;
792 		} else {
793 		    try.neg_vj = 0;
794 		}
795 	    } else {
796 		if (cishort == IPCP_VJ_COMP || cishort == IPCP_VJ_COMP_OLD) {
797 		    try.old_vj = 1;
798 		    try.vj_protocol = cishort;
799 		} else {
800 		    try.neg_vj = 0;
801 		}
802 	    }
803 	    );
804 
805     NAKCIADDR(CI_ADDR, neg_addr,
806 	      if (go->accept_local && ciaddr1) { /* Do we know our address? */
807 		  try.ouraddr = ciaddr1;
808 	      }
809 	      );
810 
811     NAKCIADDR(CI_MS_DNS1, req_dns1,
812 	      try.dnsaddr[0] = ciaddr1;
813 	      );
814 
815     NAKCIADDR(CI_MS_DNS2, req_dns2,
816 	      try.dnsaddr[1] = ciaddr1;
817 	      );
818 
819     /*
820      * There may be remaining CIs, if the peer is requesting negotiation
821      * on an option that we didn't include in our request packet.
822      * If they want to negotiate about IP addresses, we comply.
823      * If they want us to ask for compression, we refuse.
824      */
825     while (len > CILEN_VOID) {
826 	GETCHAR(citype, p);
827 	GETCHAR(cilen, p);
828 	if( (len -= cilen) < 0 )
829 	    goto bad;
830 	next = p + cilen - 2;
831 
832 	switch (citype) {
833 	case CI_COMPRESSTYPE:
834 	    if (go->neg_vj || no.neg_vj ||
835 		(cilen != CILEN_VJ && cilen != CILEN_COMPRESS))
836 		goto bad;
837 	    no.neg_vj = 1;
838 	    break;
839 	case CI_ADDRS:
840 	    if ((!go->neg_addr && go->old_addrs) || no.old_addrs
841 		|| cilen != CILEN_ADDRS)
842 		goto bad;
843 	    try.neg_addr = 1;
844 	    try.old_addrs = 1;
845 	    GETNLONG(ciaddr1, p);
846 	    if (ciaddr1 && go->accept_local)
847 		try.ouraddr = ciaddr1;
848 	    GETNLONG(ciaddr2, p);
849 	    if (ciaddr2 && go->accept_remote)
850 		try.hisaddr = ciaddr2;
851 	    no.old_addrs = 1;
852 	    break;
853 	case CI_ADDR:
854 	    if (go->neg_addr || no.neg_addr || cilen != CILEN_ADDR)
855 		goto bad;
856 	    try.old_addrs = 0;
857 	    GETNLONG(ciaddr1, p);
858 	    if (ciaddr1 && go->accept_local)
859 		try.ouraddr = ciaddr1;
860 	    if (try.ouraddr != 0)
861 		try.neg_addr = 1;
862 	    no.neg_addr = 1;
863 	    break;
864 	}
865 	p = next;
866     }
867 
868     /*
869      * OK, the Nak is good.  Now we can update state.
870      * If there are any remaining options, we ignore them.
871      */
872     if (f->state != OPENED)
873 	*go = try;
874 
875     return 1;
876 
877 bad:
878     IPCPDEBUG(("ipcp_nakci: received bad Nak!"));
879     return 0;
880 }
881 
882 
883 /*
884  * ipcp_rejci - Reject some of our CIs.
885  * Callback from fsm_rconfnakrej.
886  */
887 static int
888 ipcp_rejci(f, p, len)
889     fsm *f;
890     u_char *p;
891     int len;
892 {
893     ipcp_options *go = &ipcp_gotoptions[f->unit];
894     u_char cimaxslotindex, ciflag, cilen;
895     u_short cishort;
896     u_int32_t cilong;
897     ipcp_options try;		/* options to request next time */
898 
899     try = *go;
900     /*
901      * Any Rejected CIs must be in exactly the same order that we sent.
902      * Check packet length and CI length at each step.
903      * If we find any deviations, then this packet is bad.
904      */
905 #define REJCIADDRS(opt, neg, val1, val2) \
906     if ((neg) && \
907 	(cilen = p[1]) == CILEN_ADDRS && \
908 	len >= cilen && \
909 	p[0] == opt) { \
910 	len -= cilen; \
911 	INCPTR(2, p); \
912 	GETNLONG(cilong, p); \
913 	/* Check rejected value. */ \
914 	if (cilong != val1) \
915 	    goto bad; \
916 	GETNLONG(cilong, p); \
917 	/* Check rejected value. */ \
918 	if (cilong != val2) \
919 	    goto bad; \
920 	try.old_addrs = 0; \
921     }
922 
923 #define REJCIVJ(opt, neg, val, old, maxslot, cflag) \
924     if (go->neg && \
925 	p[1] == (old? CILEN_COMPRESS : CILEN_VJ) && \
926 	len >= p[1] && \
927 	p[0] == opt) { \
928 	len -= p[1]; \
929 	INCPTR(2, p); \
930 	GETSHORT(cishort, p); \
931 	/* Check rejected value. */  \
932 	if (cishort != val) \
933 	    goto bad; \
934 	if (!old) { \
935 	   GETCHAR(cimaxslotindex, p); \
936 	   if (cimaxslotindex != maxslot) \
937 	     goto bad; \
938 	   GETCHAR(ciflag, p); \
939 	   if (ciflag != cflag) \
940 	     goto bad; \
941         } \
942 	try.neg = 0; \
943      }
944 
945 #define REJCIADDR(opt, neg, addr) \
946     if (go->neg && \
947 	((cilen = p[1]) == CILEN_ADDR) && \
948 	len >= cilen && \
949 	p[0] == opt) { \
950 	len -= cilen; \
951 	INCPTR(2, p); \
952 	GETNLONG(cilong, p); \
953 	/* Check rejected value. */ \
954 	if (cilong != addr) \
955 	    goto bad; \
956 	try.neg = 0; \
957     }
958 
959     REJCIADDRS(CI_ADDRS, !go->neg_addr && go->old_addrs,
960 	       go->ouraddr, go->hisaddr);
961 
962     REJCIVJ(CI_COMPRESSTYPE, neg_vj, go->vj_protocol, go->old_vj,
963 	    go->maxslotindex, go->cflag);
964 
965     REJCIADDR(CI_ADDR, neg_addr, go->ouraddr);
966 
967     REJCIADDR(CI_MS_DNS1, req_dns1, go->dnsaddr[0]);
968 
969     REJCIADDR(CI_MS_DNS2, req_dns2, go->dnsaddr[1]);
970 
971     /*
972      * If there are any remaining CIs, then this packet is bad.
973      */
974     if (len != 0)
975 	goto bad;
976     /*
977      * Now we can update state.
978      */
979     if (f->state != OPENED)
980 	*go = try;
981     return 1;
982 
983 bad:
984     IPCPDEBUG(("ipcp_rejci: received bad Reject!"));
985     return 0;
986 }
987 
988 
989 /*
990  * ipcp_reqci - Check the peer's requested CIs and send appropriate response.
991  * Callback from fsm_rconfreq, Receive Configure Request
992  *
993  * Returns: CODE_CONFACK, CODE_CONFNAK or CODE_CONFREJ and input
994  * packet modified appropriately.  If reject_if_disagree is non-zero,
995  * doesn't return CODE_CONFNAK; returns CODE_CONFREJ if it can't
996  * return CODE_CONFACK.
997  */
998 static int
999 ipcp_reqci(f, p, lenp, dont_nak)
1000     fsm *f;
1001     u_char *p;		/* Requested CIs */
1002     int *lenp;			/* Length of requested CIs */
1003     bool dont_nak;
1004 {
1005     ipcp_options *wo = &ipcp_wantoptions[f->unit];
1006     ipcp_options *ho = &ipcp_hisoptions[f->unit];
1007     ipcp_options *ao = &ipcp_allowoptions[f->unit];
1008     ipcp_options *go = &ipcp_gotoptions[f->unit];
1009     int ret, newret;
1010     u_char *p0, *nakp, *rejp, *prev;
1011     u_short cishort;
1012     int len, cilen, type;
1013     u_int32_t tl, ciaddr1, ciaddr2;	/* Parsed address values */
1014     u_char maxslotindex, cflag;
1015     int d;
1016 
1017     ret = CODE_CONFACK;
1018     rejp = p0 = p;
1019     nakp = nak_buffer;
1020 
1021     /*
1022      * Reset all its options.
1023      */
1024     BZERO(ho, sizeof(*ho));
1025 
1026     /*
1027      * Process all its options.
1028      */
1029     for (len = *lenp; len > 0; len -= cilen, p = prev + cilen) {
1030 	if ((len < 2) || p[1] > len) {
1031 	    /*
1032 	     * RFC 1661 page 40 -- if the option extends beyond the
1033 	     * packet, then discard the entire packet.
1034 	     */
1035 	    return (0);
1036 	}
1037 
1038 	newret = CODE_CONFACK;
1039 	prev = p;
1040 	GETCHAR(type, p);
1041 	GETCHAR(cilen, p);
1042 
1043 	switch (type) {		/* Check CI type */
1044 	case CI_ADDRS:
1045 	    if (!ao->old_addrs || ho->neg_addr) {
1046 		newret = CODE_CONFREJ;
1047 		break;
1048 	    }
1049 
1050 	    if (cilen != CILEN_ADDRS) {
1051 		/*
1052 		 * rfc1661, page 40 -- a recongnized option with an
1053 		 * invalid length should be Nak'ed.
1054 		 */
1055 		newret = CODE_CONFNAK;
1056 		ciaddr1 = wo->hisaddr;
1057 		ciaddr2 = wo->ouraddr;
1058 	    } else {
1059 
1060 		/*
1061 		 * If it has no address, or if we both have its
1062 		 * address but disagree about it, then NAK it with our
1063 		 * idea. In particular, if we don't know its address,
1064 		 * but it does, then accept it.
1065 		 */
1066 		GETNLONG(ciaddr1, p);
1067 		if (ciaddr1 != wo->hisaddr &&
1068 		    (ciaddr1 == 0 || !wo->accept_remote)) {
1069 		    newret = CODE_CONFNAK;
1070 		    ciaddr1 = wo->hisaddr;
1071 		} else if (ciaddr1 == 0 && wo->hisaddr == 0) {
1072 		    /*
1073 		     * If neither we nor he knows his address, reject
1074 		     * the option.
1075 		     */
1076 		    newret = CODE_CONFREJ;
1077 		    wo->req_addr = 0;	/* don't NAK with 0.0.0.0 later */
1078 		    break;
1079 		} else if (ciaddr1 != 0) {
1080 		    go->hisaddr = ciaddr1;
1081 		}
1082 
1083 		/*
1084 		 * If he doesn't know our address, or if we both have
1085 		 * our address * but disagree about it, then NAK it
1086 		 * with our idea.
1087 		 */
1088 		GETNLONG(ciaddr2, p);
1089 		if (ciaddr2 != wo->ouraddr) {
1090 		    if (ciaddr2 == 0 || !wo->accept_local) {
1091 			newret = CODE_CONFNAK;
1092 			ciaddr2 = wo->ouraddr;
1093 		    } else {
1094 			go->ouraddr = ciaddr2;	/* accept peer's idea */
1095 		    }
1096 		}
1097 	    }
1098 
1099 	    if (newret == CODE_CONFNAK) {
1100 		PUTCHAR(type, nakp);
1101 		PUTCHAR(CILEN_ADDRS, nakp);
1102 		PUTNLONG(ciaddr1, nakp);
1103 		PUTNLONG(ciaddr2, nakp);
1104 	    }
1105 
1106 	    ho->old_addrs = 1;
1107 	    ho->hisaddr = ciaddr1;
1108 	    ho->ouraddr = ciaddr2;
1109 	    break;
1110 
1111 	case CI_ADDR:
1112 	    if (!ao->neg_addr || ho->old_addrs) {
1113 		newret = CODE_CONFREJ;
1114 		break;
1115 	    }
1116 
1117 	    if (cilen != CILEN_ADDR) {
1118 		/*
1119 		 * rfc1661, page 40 -- a recongnized option with an
1120 		 * invalid length should be Nak'ed.
1121 		 */
1122 		newret = CODE_CONFNAK;
1123 		ciaddr1 = wo->hisaddr;
1124 	    } else {
1125 
1126 		/*
1127 		 * If he has no address, or if we both have his
1128 		 * address but disagree about it, then NAK it with our
1129 		 * idea.  In particular, if we don't know his address,
1130 		 * but he does, then accept it.
1131 		 */
1132 		GETNLONG(ciaddr1, p);
1133 		if (ciaddr1 != wo->hisaddr &&
1134 		    (ciaddr1 == 0 || !wo->accept_remote)) {
1135 		    newret = CODE_CONFNAK;
1136 		    ciaddr1 = wo->hisaddr;
1137 		} else if (ciaddr1 == 0 && wo->hisaddr == 0 &&
1138 		    wo->default_route != 0) {
1139 		    newret = CODE_CONFNAK;
1140 		    /*
1141 		     * If this is a dialup line (default_route is
1142 		     * set), and neither side knows about its address,
1143 		     * suggest an arbitrary rfc1918 address.
1144 		     */
1145 		    ciaddr1 = htonl(0xc0a80101 + ifunit);
1146 		    dbglog("Peer address unknown; suggesting %I", ciaddr1);
1147 		} else if (ciaddr1 == 0 && wo->hisaddr == 0) {
1148 		    /*
1149 		     * If this is not a dialup line, don't ACK an
1150 		     * address of 0.0.0.0 - reject it instead.
1151 		     */
1152 		    newret = CODE_CONFREJ;
1153 		    wo->req_addr = 0;	/* don't NAK with 0.0.0.0 later */
1154 		    break;
1155 		}
1156 	    }
1157 
1158 	    if (newret == CODE_CONFNAK) {
1159 		PUTCHAR(type, nakp);
1160 		PUTCHAR(CILEN_ADDR, nakp);
1161 		PUTNLONG(ciaddr1, nakp);
1162 	    }
1163 
1164 	    ho->neg_addr = 1;
1165 	    ho->hisaddr = ciaddr1;
1166 	    break;
1167 
1168 	case CI_MS_DNS1:
1169 	case CI_MS_DNS2:
1170 	    /* Warning -- these options work backwards. */
1171 	    /* Microsoft primary or secondary DNS request */
1172 	    d = (type == CI_MS_DNS2 ? 1 : 0);
1173 
1174 	    if (ao->dnsaddr[d] == 0) {
1175 		newret = CODE_CONFREJ;
1176 		break;
1177 	    }
1178 
1179 	    if (cilen != CILEN_ADDR) {
1180 		newret = CODE_CONFNAK;
1181 	    } else {
1182 		GETNLONG(tl, p);
1183 		if (tl != ao->dnsaddr[d]) {
1184 		    newret = CODE_CONFNAK;
1185 		}
1186 	    }
1187 
1188 	    if (newret == CODE_CONFNAK) {
1189 		PUTCHAR(type, nakp);
1190 		PUTCHAR(CILEN_ADDR, nakp);
1191 		PUTNLONG(ao->dnsaddr[d], nakp);
1192 	    }
1193             break;
1194 
1195 	case CI_MS_WINS1:
1196 	case CI_MS_WINS2:
1197 	    /* Warning -- these options work backwards. */
1198 	    /* Microsoft primary or secondary WINS request */
1199 	    d = (type == CI_MS_WINS2 ? 1 : 0);
1200 
1201 	    if (ao->winsaddr[d] == 0) {
1202 		newret = CODE_CONFREJ;
1203 		break;
1204 	    }
1205 
1206 	    if (cilen != CILEN_ADDR) {
1207 		newret = CODE_CONFNAK;
1208 	    } else {
1209 		GETNLONG(tl, p);
1210 		if (tl != ao->winsaddr[d]) {
1211 		    newret = CODE_CONFNAK;
1212 		}
1213 	    }
1214 
1215 	    if (newret == CODE_CONFNAK) {
1216 		PUTCHAR(type, nakp);
1217 		PUTCHAR(CILEN_ADDR, nakp);
1218 		PUTNLONG(ao->winsaddr[d], nakp);
1219 	    }
1220             break;
1221 
1222 	case CI_COMPRESSTYPE:
1223 	    if (!ao->neg_vj) {
1224 		newret = CODE_CONFREJ;
1225 		break;
1226 	    }
1227 
1228 	    maxslotindex = ao->maxslotindex;
1229 	    cflag = ao->cflag;
1230 	    if (cilen != CILEN_VJ && cilen != CILEN_COMPRESS) {
1231 		newret = CODE_CONFNAK;
1232 		cishort = IPCP_VJ_COMP;
1233 	    } else {
1234 		GETSHORT(cishort, p);
1235 		if (cishort != IPCP_VJ_COMP &&
1236 		    (cishort != IPCP_VJ_COMP_OLD || cilen != CILEN_COMPRESS)) {
1237 		    newret = CODE_CONFNAK;
1238 		    cishort = IPCP_VJ_COMP;
1239 		} else if (cilen == CILEN_VJ) {
1240 		    GETCHAR(maxslotindex, p);
1241 		    if (maxslotindex > ao->maxslotindex) {
1242 			newret = CODE_CONFNAK;
1243 			maxslotindex = ao->maxslotindex;
1244 		    }
1245 		    GETCHAR(cflag, p);
1246 		    if (cflag != 0 && ao->cflag == 0) {
1247 			newret = CODE_CONFNAK;
1248 			cflag = 0;
1249 		    }
1250 		} else {
1251 		    ho->old_vj = 1;
1252 		    maxslotindex = MAX_STATES - 1;
1253 		    cflag = 1;
1254 		}
1255 	    }
1256 
1257 	    if (newret == CODE_CONFNAK) {
1258 		PUTCHAR(type, nakp);
1259 		if (cishort == IPCP_VJ_COMP) {
1260 		    PUTCHAR(CILEN_VJ, nakp);
1261 		    PUTSHORT(cishort, nakp);
1262 		    PUTCHAR(maxslotindex, nakp);
1263 		    PUTCHAR(cflag, nakp);
1264 		} else {
1265 		    PUTCHAR(CILEN_COMPRESS, nakp);
1266 		    PUTSHORT(cishort, nakp);
1267 		}
1268 	    }
1269 	    ho->neg_vj = 1;
1270 	    ho->vj_protocol = cishort;
1271 	    ho->maxslotindex = maxslotindex;
1272 	    ho->cflag = cflag;
1273 	    break;
1274 
1275 	default:
1276 	    newret = CODE_CONFREJ;
1277 	    break;
1278 	}
1279 
1280 	/* Cope with confused peers. */
1281 	if (cilen < 2)
1282 	    cilen = 2;
1283 
1284 	/*
1285 	 * If this is an Ack'able CI, but we're sending back a Nak,
1286 	 * don't include this CI.
1287 	 */
1288 	if (newret == CODE_CONFACK && ret != CODE_CONFACK)
1289 	    continue;
1290 
1291 	if (newret == CODE_CONFNAK) {
1292 	    if (dont_nak) {
1293 		newret = CODE_CONFREJ;
1294 	    } else {
1295 		/* Ignore subsequent Nak'able things if rejecting. */
1296 		if (ret == CODE_CONFREJ)
1297 		    continue;
1298 		ret = CODE_CONFNAK;
1299 	    }
1300 	}
1301 
1302 	if (newret == CODE_CONFREJ) {
1303 	    ret = CODE_CONFREJ;
1304 	    if (prev != rejp)
1305 		BCOPY(prev, rejp, cilen);
1306 	    rejp += cilen;
1307 	}
1308     }
1309 
1310     /*
1311      * If we aren't rejecting this packet, and we want to negotiate
1312      * their address, and they didn't send their address, then we
1313      * send a NAK with a CI_ADDR option appended.  We assume the
1314      * input buffer is long enough that we can append the extra
1315      * option safely.
1316      */
1317     if (ret != CODE_CONFREJ && !ho->neg_addr && !ho->old_addrs &&
1318 	wo->req_addr && !dont_nak) {
1319 	if (ret == CODE_CONFACK)
1320 	    wo->req_addr = 0;		/* don't ask again */
1321 	ret = CODE_CONFNAK;
1322 	PUTCHAR(CI_ADDR, nakp);
1323 	PUTCHAR(CILEN_ADDR, nakp);
1324 	PUTNLONG(wo->hisaddr, nakp);
1325     }
1326 
1327     switch (ret) {
1328     case CODE_CONFACK:
1329 	*lenp = p - p0;
1330 	sys_block_proto(PPP_IP);
1331 	break;
1332     case CODE_CONFNAK:
1333 	*lenp = nakp - nak_buffer;
1334 	BCOPY(nak_buffer, p0, *lenp);
1335 	break;
1336     case CODE_CONFREJ:
1337 	*lenp = rejp - p0;
1338 	break;
1339     }
1340 
1341     return (ret);			/* Return final code */
1342 }
1343 
1344 
1345 /*
1346  * ip_check_options - check that any IP-related options are OK,
1347  * and assign appropriate defaults.
1348  */
1349 static void
1350 ip_check_options()
1351 {
1352     struct hostent *hp;
1353     u_int32_t local;
1354     ipcp_options *wo = &ipcp_wantoptions[0];
1355 
1356     /*
1357      * Default our local IP address based on our hostname.
1358      * If local IP address already given, don't bother.
1359      */
1360     if (wo->ouraddr == 0) {
1361 	/*
1362 	 * Look up our hostname (possibly with domain name appended)
1363 	 * and take the first IP address as our local IP address.
1364 	 * If there isn't an IP address for our hostname, too bad.
1365 	 */
1366 	wo->accept_local = 1;	/* don't insist on this default value */
1367 	if ((hp = gethostbyname(hostname)) != NULL) {
1368 	    BCOPY(hp->h_addr, &local, sizeof (hp->h_addr));
1369 	    if (local != 0 && !bad_ip_adrs(local)) {
1370 		wo->ouraddr = local;
1371 		ipcp_from_hostname = 1;
1372 	    }
1373 	}
1374     }
1375 }
1376 
1377 
1378 /*
1379  * ip_demand_conf - configure the interface as though
1380  * IPCP were up, for use with dial-on-demand.
1381  */
1382 static int
1383 ip_demand_conf(u)
1384     int u;
1385 {
1386     ipcp_options *wo = &ipcp_wantoptions[u];
1387 
1388     if (wo->hisaddr == 0) {
1389 	/* make up an arbitrary address for the peer */
1390 	wo->hisaddr = htonl(0x0a707070 + ifunit);
1391 	wo->accept_remote = 1;
1392     }
1393     if (wo->ouraddr == 0) {
1394 	/* make up an arbitrary address for us */
1395 	wo->ouraddr = htonl(0x0a404040 + ifunit);
1396 	wo->accept_local = 1;
1397 	disable_defaultip = 1;	/* don't tell the peer this address */
1398     }
1399     if (!sifaddr(u, wo->ouraddr, wo->hisaddr, GetMask(wo->ouraddr)))
1400 	return 0;
1401     if (!sifup(u))
1402 	return 0;
1403     if (!sifnpmode(u, PPP_IP, NPMODE_QUEUE))
1404 	return 0;
1405     if (wo->default_route && sifdefaultroute(u, wo->ouraddr, wo->hisaddr))
1406 	default_route_set[u] = 1;
1407     if (wo->proxy_arp && sifproxyarp(u, wo->hisaddr, proxy_arp_quiet[u]))
1408 	proxy_arp_set[u] = 1;
1409 
1410     notice("local  IP address %I", wo->ouraddr);
1411     notice("remote IP address %I", wo->hisaddr);
1412 
1413     return 1;
1414 }
1415 
1416 
1417 /*
1418  * ipcp_up - IPCP has come UP.
1419  *
1420  * Configure the IP network interface appropriately and bring it up.
1421  */
1422 static void
1423 ipcp_up(f)
1424     fsm *f;
1425 {
1426     u_int32_t mask;
1427     ipcp_options *ho = &ipcp_hisoptions[f->unit];
1428     ipcp_options *go = &ipcp_gotoptions[f->unit];
1429     ipcp_options *wo = &ipcp_wantoptions[f->unit];
1430 
1431     IPCPDEBUG(("ipcp: up"));
1432 
1433     /*
1434      * We must have a non-zero IP address for both ends of the link.
1435      */
1436     if (ho->hisaddr == 0)
1437 	ho->hisaddr = wo->hisaddr;
1438 
1439     if (ho->hisaddr == 0) {
1440 	if (wo->accept_remote) {
1441 	    /* Pick some rfc1918 address. */
1442 	    ho->hisaddr = htonl(0xc0a80101 + ifunit);
1443 	    dbglog("Peer refused to provide his address; assuming %I",
1444 		ho->hisaddr);
1445 	} else {
1446 	    error("Could not determine remote IP address");
1447 	    ipcp_close(f->unit, "Could not determine remote IP address");
1448 	    return;
1449 	}
1450     }
1451     if (go->ouraddr == 0) {
1452 	error("Could not determine local IP address");
1453 	ipcp_close(f->unit, "Could not determine local IP address");
1454 	return;
1455     }
1456     script_setenv("IPLOCAL", ip_ntoa(go->ouraddr), 0);
1457     script_setenv("IPREMOTE", ip_ntoa(ho->hisaddr), 1);
1458 
1459     /*
1460      * Check that the peer is allowed to use the IP address it wants.
1461      */
1462     if (!auth_ip_addr(f->unit, ho->hisaddr)) {
1463 	error("Peer is not authorized to use remote address %I", ho->hisaddr);
1464 	ipcp_close(f->unit, "Unauthorized remote IP address");
1465 	return;
1466     }
1467 
1468     if ((go->req_dns1 && go->dnsaddr[0] != 0) ||
1469 	(go->req_dns2 && go->dnsaddr[1] != 0)) {
1470 	script_setenv("USEPEERDNS", "1", 0);
1471 	if (go->dnsaddr[0] != 0)
1472 	    script_setenv("DNS1", ip_ntoa(go->dnsaddr[0]), 0);
1473 	if (go->dnsaddr[1] != 0)
1474 	    script_setenv("DNS2", ip_ntoa(go->dnsaddr[1]), 0);
1475 	create_resolv(go->dnsaddr[0], go->dnsaddr[1]);
1476     }
1477 
1478     /* set tcp compression */
1479     if (sifvjcomp(f->unit, ho->neg_vj, ho->cflag, ho->maxslotindex) != 1) {
1480 	ipcp_close(f->unit, "Could not enable VJ TCP header compression");
1481 	return;
1482     }
1483 
1484     /*
1485      * If we are doing dial-on-demand, the interface is already
1486      * configured, so we put out any saved-up packets, then set the
1487      * interface to pass IP packets.
1488      */
1489     if (demand) {
1490 	if (go->ouraddr != wo->ouraddr || ho->hisaddr != wo->hisaddr) {
1491 	    ipcp_clear_addrs(f->unit, wo->ouraddr, wo->hisaddr);
1492 	    if (go->ouraddr != wo->ouraddr) {
1493 		warn("Local IP address changed to %I", go->ouraddr);
1494 		script_setenv("OLDIPLOCAL", ip_ntoa(wo->ouraddr), 0);
1495 		wo->ouraddr = go->ouraddr;
1496 	    } else
1497 		script_unsetenv("OLDIPLOCAL");
1498 	    if (ho->hisaddr != wo->hisaddr) {
1499 		warn("Remote IP address changed to %I", ho->hisaddr);
1500 		script_setenv("OLDIPREMOTE", ip_ntoa(wo->hisaddr), 0);
1501 		wo->hisaddr = ho->hisaddr;
1502 	    } else
1503 		script_unsetenv("OLDIPREMOTE");
1504 
1505 	    /* Set the interface to the new addresses */
1506 	    mask = GetMask(go->ouraddr);
1507 	    if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask)) {
1508 		warn("Interface configuration failed");
1509 		ipcp_close(f->unit, "Interface configuration failed");
1510 		return;
1511 	    }
1512 
1513 	    /* assign a default route through the interface if required */
1514 	    if (wo->default_route)
1515 		if (sifdefaultroute(f->unit, go->ouraddr, ho->hisaddr))
1516 		    default_route_set[f->unit] = 1;
1517 
1518 	    /* Make a proxy ARP entry if requested. */
1519 	    if (wo->proxy_arp &&
1520 		sifproxyarp(f->unit, ho->hisaddr, proxy_arp_quiet[f->unit]))
1521 		proxy_arp_set[f->unit] = 1;
1522 
1523 	}
1524 	demand_rexmit(PPP_IP);
1525 	if (sifnpmode(f->unit, PPP_IP, NPMODE_PASS) != 1) {
1526 	    ipcp_close(f->unit, "Interface configuration failed.");
1527 	    return;
1528 	}
1529 
1530     } else {
1531 	/*
1532 	 * Set IP addresses and (if specified) netmask.
1533 	 */
1534 	mask = GetMask(go->ouraddr);
1535 
1536 #if SIFUPFIRST
1537 	/* bring the interface up for IP */
1538 	if (!sifup(f->unit)) {
1539 	    warn("Interface failed to come up");
1540 	    ipcp_close(f->unit, "Interface configuration failed");
1541 	    return;
1542 	}
1543 #endif
1544 
1545 	if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask)) {
1546 	    warn("Interface configuration failed");
1547 	    ipcp_close(f->unit, "Interface configuration failed");
1548 	    return;
1549 	}
1550 
1551 #if !SIFUPFIRST
1552 	/* bring the interface up for IP */
1553 	if (!sifup(f->unit)) {
1554 	    warn("Interface failed to come up");
1555 	    ipcp_close(f->unit, "Interface configuration failed");
1556 	    return;
1557 	}
1558 #endif
1559 
1560 	if (sifnpmode(f->unit, PPP_IP, NPMODE_PASS) != 1) {
1561 	    ipcp_close(f->unit, "Interface configuration failed.");
1562 	    return;
1563 	}
1564 
1565 	/* assign a default route through the interface if required */
1566 	if (wo->default_route)
1567 	    if (sifdefaultroute(f->unit, go->ouraddr, ho->hisaddr))
1568 		default_route_set[f->unit] = 1;
1569 
1570 	/* Make a proxy ARP entry if requested. */
1571 	if (wo->proxy_arp &&
1572 	    sifproxyarp(f->unit, ho->hisaddr, proxy_arp_quiet[f->unit]))
1573 	    proxy_arp_set[f->unit] = 1;
1574 
1575 	wo->ouraddr = go->ouraddr;
1576 
1577 	notice("local  IP address %I", go->ouraddr);
1578 	notice("remote IP address %I", ho->hisaddr);
1579 	if (go->dnsaddr[0] != 0)
1580 	    notice("primary   DNS address %I", go->dnsaddr[0]);
1581 	if (go->dnsaddr[1] != 0)
1582 	    notice("secondary DNS address %I", go->dnsaddr[1]);
1583     }
1584 
1585     np_up(f->unit, PPP_IP);
1586     ipcp_is_up[f->unit] = 1;
1587 
1588     if (ip_up_hook != NULL)
1589 	(*ip_up_hook)();
1590 
1591     /*
1592      * Execute the ip-up script, like this:
1593      *	/etc/ppp/ip-up interface tty speed local-IP remote-IP
1594      */
1595     if (ipcp_script_state == s_down && ipcp_script_pid == 0) {
1596 	ipcp_script_state = s_up;
1597 	ipcp_script(_PATH_IPUP);
1598     }
1599     sys_unblock_proto(PPP_IP);
1600 }
1601 
1602 
1603 /*
1604  * ipcp_down - IPCP has gone DOWN.
1605  *
1606  * Take the IP network interface down, clear its addresses
1607  * and delete routes through it.
1608  */
1609 static void
1610 ipcp_down(f)
1611     fsm *f;
1612 {
1613     IPCPDEBUG(("ipcp: down"));
1614     /* XXX a bit IPv4-centric here, we only need to get the stats
1615      * before the interface is marked down. */
1616     update_link_stats(f->unit);
1617     if (ip_down_hook != NULL)
1618 	(*ip_down_hook)();
1619     if (ipcp_is_up[f->unit]) {
1620 	ipcp_is_up[f->unit] = 0;
1621 	np_down(f->unit, PPP_IP);
1622     }
1623     if (sifvjcomp(f->unit, 0, 0, 0) != 1) {
1624 	if (debug)
1625 	    warn("Failed to disable VJ TCP header compression.");
1626     }
1627 
1628     /*
1629      * If we are doing dial-on-demand, set the interface
1630      * to queue up outgoing packets (for now).
1631      */
1632     if (demand) {
1633 	if (sifnpmode(f->unit, PPP_IP, NPMODE_QUEUE) != 1) {
1634 	    if (debug)
1635 		warn("Failed to enable Queueing on outgoing packets.");
1636 	}
1637     } else {
1638 	if (sifnpmode(f->unit, PPP_IP, NPMODE_ERROR) != 1) {
1639 	    if (debug)
1640 		warn("Could not set interface to drop packets.");
1641 	}
1642 	if (sifdown(f->unit) != 1)
1643 	    warn("Could not bring interface down.");
1644 	ipcp_clear_addrs(f->unit, ipcp_gotoptions[f->unit].ouraddr,
1645 			 ipcp_hisoptions[f->unit].hisaddr);
1646     }
1647 
1648     /* Execute the ip-down script */
1649     if (ipcp_script_state == s_up && ipcp_script_pid == 0) {
1650 	ipcp_script_state = s_down;
1651 	ipcp_script(_PATH_IPDOWN);
1652     }
1653 }
1654 
1655 
1656 /*
1657  * ipcp_clear_addrs() - clear the interface addresses, routes,
1658  * proxy arp entries, etc.
1659  */
1660 static void
1661 ipcp_clear_addrs(unit, ouraddr, hisaddr)
1662     int unit;
1663     u_int32_t ouraddr;  /* local address */
1664     u_int32_t hisaddr;  /* remote address */
1665 {
1666     if (proxy_arp_set[unit]) {
1667 	(void) cifproxyarp(unit, hisaddr);
1668 	proxy_arp_set[unit] = 0;
1669     }
1670     if (default_route_set[unit]) {
1671 	(void) cifdefaultroute(unit, ouraddr, hisaddr);
1672 	default_route_set[unit] = 0;
1673     }
1674     if (cifaddr(unit, ouraddr, hisaddr) != 1)
1675 	warn("Could not clear addresses");
1676 }
1677 
1678 
1679 /*
1680  * ipcp_finished - possibly shut down the lower layers.
1681  */
1682 static void
1683 ipcp_finished(f)
1684     fsm *f;
1685 {
1686     np_finished(f->unit, PPP_IP);
1687 }
1688 
1689 
1690 /*
1691  * ipcp_script_done - called when the ip-up or ip-down script
1692  * has finished.
1693  */
1694 /*ARGSUSED*/
1695 static void
1696 ipcp_script_done(arg, status)
1697     void *arg;
1698     int status;
1699 {
1700     ipcp_script_pid = 0;
1701     switch (ipcp_script_state) {
1702     case s_up:
1703 	if (ipcp_fsm[0].state != OPENED) {
1704 	    ipcp_script_state = s_down;
1705 	    ipcp_script(_PATH_IPDOWN);
1706 	}
1707 	break;
1708     case s_down:
1709 	if (ipcp_fsm[0].state == OPENED) {
1710 	    ipcp_script_state = s_up;
1711 	    ipcp_script(_PATH_IPUP);
1712 	}
1713 	break;
1714     }
1715 }
1716 
1717 
1718 /*
1719  * ipcp_script - Execute a script with arguments
1720  * interface-name tty-name speed local-IP remote-IP.
1721  */
1722 static void
1723 ipcp_script(script)
1724     char *script;
1725 {
1726     char strspeed[32], strlocal[32], strremote[32];
1727     char *argv[8];
1728 
1729     (void) slprintf(strspeed, sizeof(strspeed), "%d", baud_rate);
1730     (void) slprintf(strlocal, sizeof(strlocal), "%I",
1731 	ipcp_gotoptions[0].ouraddr);
1732     (void) slprintf(strremote, sizeof(strremote), "%I",
1733 	ipcp_hisoptions[0].hisaddr);
1734 
1735     argv[0] = script;
1736     argv[1] = ifname;
1737     argv[2] = devnam;
1738     argv[3] = strspeed;
1739     argv[4] = strlocal;
1740     argv[5] = strremote;
1741     argv[6] = ipparam;
1742     argv[7] = NULL;
1743     ipcp_script_pid = run_program(script, argv, 0, ipcp_script_done, NULL);
1744 }
1745 
1746 /*
1747  * create_resolv - create the replacement resolv.conf file
1748  */
1749 static void
1750 create_resolv(peerdns1, peerdns2)
1751     u_int32_t peerdns1, peerdns2;
1752 {
1753     FILE *f;
1754 
1755     f = fopen(_PATH_RESOLV, "w");
1756     if (f == NULL) {
1757 	error("Failed to create %s: %m", _PATH_RESOLV);
1758 	return;
1759     }
1760 
1761     if (peerdns1)
1762 	if (fprintf(f, "nameserver %s\n", ip_ntoa(peerdns1)) <= 0)
1763 	    error("Write failed to %s: %m", _PATH_RESOLV);
1764 
1765     if (peerdns2)
1766 	if (fprintf(f, "nameserver %s\n", ip_ntoa(peerdns2)) <= 0)
1767 	    error("Write failed to %s: %m", _PATH_RESOLV);
1768 
1769     if (fclose(f) != 0)
1770 	error("Failed to close %s: %m", _PATH_RESOLV);
1771 }
1772 
1773 /*
1774  * ipcp_printpkt - print the contents of an IPCP packet.
1775  */
1776 static int
1777 ipcp_printpkt(p, plen, printer, arg)
1778     u_char *p;
1779     int plen;
1780     void (*printer) __P((void *, const char *, ...));
1781     void *arg;
1782 {
1783     int code, id, len, olen;
1784     u_char *pstart, *optend;
1785     u_short cishort;
1786     u_int32_t cilong;
1787 
1788     if (plen < HEADERLEN)
1789 	return 0;
1790     pstart = p;
1791     GETCHAR(code, p);
1792     GETCHAR(id, p);
1793     GETSHORT(len, p);
1794     if (len < HEADERLEN || len > plen)
1795 	return 0;
1796 
1797     printer(arg, " %s id=0x%x", code_name(code, 1), id);
1798     len -= HEADERLEN;
1799     switch (code) {
1800     case CODE_CONFREQ:
1801     case CODE_CONFACK:
1802     case CODE_CONFNAK:
1803     case CODE_CONFREJ:
1804 	/* print option list */
1805 	while (len >= 2) {
1806 	    GETCHAR(code, p);
1807 	    GETCHAR(olen, p);
1808 	    p -= 2;
1809 	    if (olen < 2 || olen > len) {
1810 		break;
1811 	    }
1812 	    printer(arg, " <");
1813 	    len -= olen;
1814 	    optend = p + olen;
1815 	    switch (code) {
1816 	    case CI_ADDRS:
1817 		if (olen == CILEN_ADDRS) {
1818 		    p += 2;
1819 		    GETNLONG(cilong, p);
1820 		    printer(arg, "addrs %I", cilong);
1821 		    GETNLONG(cilong, p);
1822 		    printer(arg, " %I", cilong);
1823 		}
1824 		break;
1825 	    case CI_COMPRESSTYPE:
1826 		if (olen >= CILEN_COMPRESS) {
1827 		    p += 2;
1828 		    GETSHORT(cishort, p);
1829 		    printer(arg, "compress ");
1830 		    switch (cishort) {
1831 		    case IPCP_VJ_COMP:
1832 			printer(arg, "VJ");
1833 			break;
1834 		    case IPCP_VJ_COMP_OLD:
1835 			printer(arg, "old-VJ");
1836 			break;
1837 		    default:
1838 			printer(arg, "0x%x", cishort);
1839 		    }
1840 		}
1841 		break;
1842 	    case CI_ADDR:
1843 		if (olen == CILEN_ADDR) {
1844 		    p += 2;
1845 		    GETNLONG(cilong, p);
1846 		    printer(arg, "addr %I", cilong);
1847 		}
1848 		break;
1849 	    case CI_MS_DNS1:
1850 	    case CI_MS_DNS2:
1851 	        p += 2;
1852 		GETNLONG(cilong, p);
1853 		printer(arg, "ms-dns%d %I", (code == CI_MS_DNS1 ? 1 : 2),
1854 		    cilong);
1855 		break;
1856 	    case CI_MS_WINS1:
1857 	    case CI_MS_WINS2:
1858 	        p += 2;
1859 		GETNLONG(cilong, p);
1860 		printer(arg, "ms-wins%d %I", (code == CI_MS_WINS1 ? 1 : 2),
1861 		    cilong);
1862 		break;
1863 	    case CI_SUBNET:
1864 		p += 2;
1865 		GETNLONG(cilong, p);
1866 		printer(arg, "subnet %I", cilong);
1867 		break;
1868 	    }
1869 	    while (p < optend) {
1870 		GETCHAR(code, p);
1871 		printer(arg, " %.2x", code);
1872 	    }
1873 	    printer(arg, ">");
1874 	}
1875 	break;
1876 
1877     case CODE_TERMACK:
1878     case CODE_TERMREQ:
1879 	if (len > 0 && *p >= ' ' && *p < 0x7f) {
1880 	    printer(arg, " ");
1881 	    print_string((char *)p, len, printer, arg);
1882 	    p += len;
1883 	    len = 0;
1884 	}
1885 	break;
1886     }
1887 
1888     /* print the rest of the bytes in the packet */
1889     for (; len > 0; --len) {
1890 	GETCHAR(code, p);
1891 	printer(arg, " %.2x", code);
1892     }
1893 
1894     return p - pstart;
1895 }
1896 
1897 char *
1898 tcp_flag_decode(val)
1899     int val;
1900 {
1901     static char buf[32];
1902     char *cp = buf;
1903 
1904     if (val & TH_URG)
1905 	*cp++ = 'U';
1906     if (val & TH_ACK)
1907 	*cp++ = 'A';
1908     if (val & TH_PUSH)
1909 	*cp++ = 'P';
1910     if (val & TH_RST)
1911 	*cp++ = 'R';
1912     if (val & TH_SYN)
1913 	*cp++ = 'S';
1914     if (val & TH_FIN)
1915 	*cp++ = 'F';
1916     if (cp != buf)
1917 	*cp++ = ' ';
1918     *cp = '\0';
1919     return buf;
1920 }
1921 
1922 /*
1923  * ip_active_pkt - see if this IP packet is worth bringing the link up for.
1924  * We don't bring the link up for IP fragments or for TCP FIN packets
1925  * with no data.
1926  */
1927 
1928 static int
1929 ip_active_pkt(pkt, len)
1930     u_char *pkt;
1931     int len;
1932 {
1933     u_char *tcp;
1934     struct protoent *pep;
1935     int val;
1936     int hlen;
1937     char buf[32], *cp;
1938     u_int32_t src, dst;
1939 
1940     len -= PPP_HDRLEN;
1941     pkt += PPP_HDRLEN;
1942     if (len < IP_HDRLEN) {
1943 	dbglog("IP packet of length %d is not activity", len);
1944 	return 0;
1945     }
1946     src = get_ipsrc(pkt);
1947     dst = get_ipdst(pkt);
1948     if ((get_ipoff(pkt) & IP_OFFMASK) != 0) {
1949 	dbglog("IP fragment from %I->%I is not activity", src, dst);
1950 	return 0;
1951     }
1952     val = get_ipproto(pkt);
1953     if (val != IPPROTO_TCP) {
1954 	if (debug) {
1955 	    if ((pep = getprotobynumber(val)) != NULL) {
1956 		cp = pep->p_name;
1957 	    } else {
1958 		(void) slprintf(buf, sizeof (buf), "IP proto %d", val);
1959 		cp = buf;
1960 	    }
1961 	    info("%s from %I->%I is activity", cp, src, dst);
1962 	}
1963 	return 1;
1964     }
1965     hlen = get_iphl(pkt) * 4;
1966     if (len < hlen + TCP_HDRLEN) {
1967 	dbglog("Bad TCP length %d<%d+%d %I->%I is not activity", len, hlen,
1968 	    TCP_HDRLEN, src, dst);
1969 	return 0;
1970     }
1971     tcp = pkt + hlen;
1972     val = get_tcpflags(tcp);
1973     hlen += get_tcpoff(tcp) * 4;
1974     if ((val & TH_FIN) != 0 && len == hlen) {
1975 	dbglog("Empty TCP FIN %I->%I is not activity", src, dst);
1976 	return 0;
1977     }
1978     info("TCP %d data %s%I->%I is activity", len - hlen,
1979 	tcp_flag_decode(get_tcpflags(tcp)), src, dst);
1980     return 1;
1981 }
1982 
1983 static void
1984 ipcp_print_stat(unit, strptr)
1985     int unit;
1986     FILE *strptr;
1987 {
1988     ipcp_options *go = &ipcp_gotoptions[unit];
1989     ipcp_options *ho = &ipcp_hisoptions[unit];
1990     char *proto_name = ipcp_protent.name;
1991 
1992     if (!ipcp_protent.enabled_flag) {
1993 	(void) flprintf(strptr, "%s disabled\n", proto_name);
1994 	return;
1995     }
1996 
1997     (void) flprintf(strptr, "%s state: %s", proto_name,
1998 	fsm_state(ipcp_fsm[unit].state));
1999     (void) flprintf(strptr, "%s local %I  remote %I", proto_name, go->ouraddr,
2000 	ho->ouraddr);
2001 }
2002