xref: /openbsd/sbin/isakmpd/log.c (revision 3d8817e4)
1 /* $OpenBSD: log.c,v 1.61 2011/04/16 10:30:29 sthen Exp $	 */
2 /* $EOM: log.c,v 1.30 2000/09/29 08:19:23 niklas Exp $	 */
3 
4 /*
5  * Copyright (c) 1998, 1999, 2001 Niklas Hallqvist.  All rights reserved.
6  * Copyright (c) 1999, 2000, 2001, 2003 H�kan Olsson.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 /*
30  * This code was written under funding by Ericsson Radio Systems.
31  */
32 
33 #include <sys/types.h>
34 #include <sys/time.h>
35 
36 #include <sys/socket.h>
37 #include <sys/stat.h>
38 #include <sys/uio.h>
39 #include <netinet/in.h>
40 #include <netinet/in_systm.h>
41 #include <netinet/ip.h>
42 #include <netinet/ip6.h>
43 #include <netinet/udp.h>
44 #include <arpa/inet.h>
45 
46 #include <pcap.h>
47 
48 #include <errno.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #include <syslog.h>
53 #include <stdarg.h>
54 #include <unistd.h>
55 
56 #include "conf.h"
57 #include "isakmp_num.h"
58 #include "log.h"
59 #include "monitor.h"
60 #include "util.h"
61 
62 static void	_log_print(int, int, const char *, va_list, int, int);
63 
64 static FILE	*log_output;
65 
66 int		verbose_logging = 0;
67 static int	log_level[LOG_ENDCLASS];
68 
69 #define TCPDUMP_MAGIC	0xa1b2c3d4
70 #define SNAPLEN		(64 * 1024)
71 
72 struct packhdr {
73 	struct pcap_pkthdr pcap;/* pcap file packet header */
74 	u_int32_t sa_family;	/* address family */
75 	union {
76 		struct ip       ip4;	/* IPv4 header (w/o options) */
77 		struct ip6_hdr  ip6;	/* IPv6 header */
78 	} ip;
79 };
80 
81 struct isakmp_hdr {
82 	u_int8_t        icookie[8], rcookie[8];
83 	u_int8_t        next, ver, type, flags;
84 	u_int32_t       msgid, len;
85 };
86 
87 static char    *pcaplog_file = NULL;
88 static FILE    *packet_log;
89 static u_int8_t *packet_buf = NULL;
90 
91 static int      udp_cksum(struct packhdr *, const struct udphdr *,
92     u_int16_t *);
93 static u_int16_t in_cksum(const u_int16_t *, int);
94 
95 void
96 log_init(int debug)
97 {
98 	if (debug)
99 		log_output = stderr;
100 	else
101 		log_to(0);	/* syslog */
102 }
103 
104 void
105 log_reinit(void)
106 {
107 	struct conf_list *logging;
108 	struct conf_list_node *logclass;
109 	int		class, level;
110 
111 	logging = conf_get_list("General", "Logverbose");
112 	if (logging) {
113 		verbose_logging = 1;
114 		conf_free_list(logging);
115 	}
116 	logging = conf_get_list("General", "Loglevel");
117 	if (!logging)
118 		return;
119 
120 	for (logclass = TAILQ_FIRST(&logging->fields); logclass;
121 	    logclass = TAILQ_NEXT(logclass, link)) {
122 		if (sscanf(logclass->field, "%d=%d", &class, &level) != 2) {
123 			if (sscanf(logclass->field, "A=%d", &level) == 1)
124 				for (class = 0; class < LOG_ENDCLASS; class++)
125 					log_debug_cmd(class, level);
126 			else {
127 				log_print("init: invalid logging class or "
128 				    "level: %s", logclass->field);
129 				continue;
130 			}
131 		} else
132 			log_debug_cmd(class, level);
133 	}
134 	conf_free_list(logging);
135 }
136 
137 void
138 log_to(FILE *f)
139 {
140 	if (!log_output && f)
141 		closelog();
142 	log_output = f;
143 	if (!f)
144 		openlog("isakmpd", LOG_PID | LOG_CONS, LOG_DAEMON);
145 }
146 
147 FILE *
148 log_current(void)
149 {
150 	return log_output;
151 }
152 
153 static char *
154 _log_get_class(int error_class)
155 {
156 	/* XXX For test purposes. To be removed later on?  */
157 	static char	*class_text[] = LOG_CLASSES_TEXT;
158 
159 	if (error_class < 0)
160 		return "Dflt";
161 	else if (error_class >= LOG_ENDCLASS)
162 		return "Unkn";
163 	else
164 		return class_text[error_class];
165 }
166 
167 static void
168 _log_print(int error, int syslog_level, const char *fmt, va_list ap,
169     int class, int level)
170 {
171 	char		buffer[LOG_SIZE], nbuf[LOG_SIZE + 32];
172 	static const char fallback_msg[] =
173 	    "write to log file failed (errno %d), redirecting to syslog";
174 	int		len;
175 	struct tm      *tm;
176 	struct timeval  now;
177 	time_t          t;
178 
179 	len = vsnprintf(buffer, sizeof buffer, fmt, ap);
180 	if (len > 0 && len < (int) sizeof buffer - 1 && error)
181 		snprintf(buffer + len, sizeof buffer - len, ": %s",
182 		    strerror(errno));
183 	if (log_output) {
184 		gettimeofday(&now, 0);
185 		t = now.tv_sec;
186 		tm = localtime(&t);
187 		if (class >= 0)
188 			snprintf(nbuf, sizeof nbuf,
189 			    "%02d%02d%02d.%06ld %s %02d ",
190 			    tm->tm_hour, tm->tm_min, tm->tm_sec, now.tv_usec,
191 			    _log_get_class(class), level);
192 		else /* LOG_PRINT (-1) or LOG_REPORT (-2) */
193 			snprintf(nbuf, sizeof nbuf, "%02d%02d%02d.%06ld %s ",
194 			    tm->tm_hour, tm->tm_min, tm->tm_sec, now.tv_usec,
195 			    class == LOG_PRINT ? "Default" : "Report>");
196 		strlcat(nbuf, buffer, sizeof nbuf);
197 		strlcat(nbuf, getuid() ? "" : " [priv]", LOG_SIZE + 32);
198 		strlcat(nbuf, "\n", sizeof nbuf);
199 
200 		if (fwrite(nbuf, strlen(nbuf), 1, log_output) == 0) {
201 			/* Report fallback.  */
202 			syslog(LOG_ALERT, fallback_msg, errno);
203 			fprintf(log_output, fallback_msg, errno);
204 
205 			/*
206 			 * Close log_output to prevent isakmpd from locking
207 			 * the file.  We may need to explicitly close stdout
208 			 * to do this properly.
209 			 * XXX - Figure out how to match two FILE *'s and
210 			 * rewrite.
211 			 */
212 			if (fileno(log_output) != -1 &&
213 			    fileno(stdout) == fileno(log_output))
214 				fclose(stdout);
215 			fclose(log_output);
216 
217 			/* Fallback to syslog.  */
218 			log_to(0);
219 
220 			/* (Re)send current message to syslog().  */
221 			syslog(class == LOG_REPORT ? LOG_ALERT :
222 			    syslog_level, "%s", buffer);
223 		}
224 	} else
225 		syslog(class == LOG_REPORT ? LOG_ALERT : syslog_level, "%s",
226 		    buffer);
227 }
228 
229 void
230 log_debug(int cls, int level, const char *fmt, ...)
231 {
232 	va_list         ap;
233 
234 	/*
235 	 * If we are not debugging this class, or the level is too low, just
236 	 * return.
237          */
238 	if (cls >= 0 && (log_level[cls] == 0 || level > log_level[cls]))
239 		return;
240 	va_start(ap, fmt);
241 	_log_print(0, LOG_INFO, fmt, ap, cls, level);
242 	va_end(ap);
243 }
244 
245 void
246 log_debug_buf(int cls, int level, const char *header, const u_int8_t *buf,
247     size_t sz)
248 {
249 	size_t	i, j;
250 	char	s[73];
251 
252 	/*
253 	 * If we are not debugging this class, or the level is too low, just
254 	 * return.
255          */
256 	if (cls >= 0 && (log_level[cls] == 0 || level > log_level[cls]))
257 		return;
258 
259 	log_debug(cls, level, "%s:", header);
260 	for (i = j = 0; i < sz;) {
261 		snprintf(s + j, sizeof s - j, "%02x", buf[i++]);
262 		j += strlen(s + j);
263 		if (i % 4 == 0) {
264 			if (i % 32 == 0) {
265 				s[j] = '\0';
266 				log_debug(cls, level, "%s", s);
267 				j = 0;
268 			} else
269 				s[j++] = ' ';
270 		}
271 	}
272 	if (j) {
273 		s[j] = '\0';
274 		log_debug(cls, level, "%s", s);
275 	}
276 }
277 
278 void
279 log_debug_cmd(int cls, int level)
280 {
281 	if (cls < 0 || cls >= LOG_ENDCLASS) {
282 		log_print("log_debug_cmd: invalid debugging class %d", cls);
283 		return;
284 	}
285 	if (level < 0) {
286 		log_print("log_debug_cmd: invalid debugging level %d for "
287 		    "class %d", level, cls);
288 		return;
289 	}
290 	if (level == log_level[cls])
291 		log_print("log_debug_cmd: log level unchanged for class %d",
292 		    cls);
293 	else {
294 		log_print("log_debug_cmd: log level changed from %d to %d "
295 		    "for class %d", log_level[cls], level, cls);
296 		log_level[cls] = level;
297 	}
298 }
299 
300 void
301 log_debug_toggle(void)
302 {
303 	static int	log_level_copy[LOG_ENDCLASS], toggle = 0;
304 
305 	if (!toggle) {
306 		LOG_DBG((LOG_MISC, 50, "log_debug_toggle: "
307 		    "debug levels cleared"));
308 		memcpy(&log_level_copy, &log_level, sizeof log_level);
309 		bzero(&log_level, sizeof log_level);
310 	} else {
311 		memcpy(&log_level, &log_level_copy, sizeof log_level);
312 		LOG_DBG((LOG_MISC, 50, "log_debug_toggle: "
313 		    "debug levels restored"));
314 	}
315 	toggle = !toggle;
316 }
317 
318 void
319 log_print(const char *fmt, ...)
320 {
321 	va_list	ap;
322 
323 	va_start(ap, fmt);
324 	_log_print(0, LOG_NOTICE, fmt, ap, LOG_PRINT, 0);
325 	va_end(ap);
326 }
327 
328 void
329 log_verbose(const char *fmt, ...)
330 {
331 	va_list	ap;
332 
333 	if (verbose_logging == 0)
334 		return;
335 
336 	va_start(ap, fmt);
337 	_log_print(0, LOG_NOTICE, fmt, ap, LOG_PRINT, 0);
338 	va_end(ap);
339 }
340 
341 void
342 log_error(const char *fmt, ...)
343 {
344 	va_list	ap;
345 
346 	va_start(ap, fmt);
347 	_log_print(1, LOG_ERR, fmt, ap, LOG_PRINT, 0);
348 	va_end(ap);
349 }
350 
351 void
352 log_errorx(const char *fmt, ...)
353 {
354 	va_list ap;
355 
356 	va_start(ap, fmt);
357 	_log_print(0, LOG_ERR, fmt, ap, LOG_PRINT, 0);
358 	va_end(ap);
359 }
360 
361 void
362 log_fatal(const char *fmt, ...)
363 {
364 	va_list	ap;
365 
366 	va_start(ap, fmt);
367 	_log_print(1, LOG_CRIT, fmt, ap, LOG_PRINT, 0);
368 	va_end(ap);
369 	monitor_exit(1);
370 }
371 
372 void
373 log_fatalx(const char *fmt, ...)
374 {
375 	va_list	ap;
376 
377 	va_start(ap, fmt);
378 	_log_print(0, LOG_CRIT, fmt, ap, LOG_PRINT, 0);
379 	va_end(ap);
380 	monitor_exit(1);
381 }
382 
383 void
384 log_packet_init(char *newname)
385 {
386 	struct pcap_file_header sf_hdr;
387 	struct stat     st;
388 	mode_t          old_umask;
389 	char           *mode;
390 
391 	/* Allocate packet buffer first time through.  */
392 	if (!packet_buf)
393 		packet_buf = malloc(SNAPLEN);
394 
395 	if (!packet_buf) {
396 		log_error("log_packet_init: malloc (%d) failed", SNAPLEN);
397 		return;
398 	}
399 	if (pcaplog_file && strcmp(pcaplog_file, PCAP_FILE_DEFAULT) != 0)
400 		free(pcaplog_file);
401 
402 	pcaplog_file = strdup(newname);
403 	if (!pcaplog_file) {
404 		log_error("log_packet_init: strdup (\"%s\") failed", newname);
405 		return;
406 	}
407 	/* Does the file already exist?  XXX lstat() or stat()?  */
408 	/* XXX This is a fstat! */
409 	if (monitor_stat(pcaplog_file, &st) == 0) {
410 		/* Sanity checks.  */
411 		if (!S_ISREG(st.st_mode)) {
412 			log_print("log_packet_init: existing capture file is "
413 			    "not a regular file");
414 			return;
415 		}
416 		if ((st.st_mode & (S_IRWXG | S_IRWXO)) != 0) {
417 			log_print("log_packet_init: existing capture "
418 			    "file has bad modes");
419 			return;
420 		}
421 		/*
422 		 * XXX It would be nice to check if it actually is a pcap
423 		 * file...
424 		 */
425 
426 		mode = "a";
427 	} else
428 		mode = "w";
429 
430 	old_umask = umask(S_IRWXG | S_IRWXO);
431 	packet_log = monitor_fopen(pcaplog_file, mode);
432 	umask(old_umask);
433 
434 	if (!packet_log) {
435 		log_error("log_packet_init: fopen (\"%s\", \"%s\") failed",
436 		    pcaplog_file, mode);
437 		return;
438 	}
439 	log_print("log_packet_init: "
440 	    "starting IKE packet capture to file \"%s\"", pcaplog_file);
441 
442 	/* If this is a new file, we need to write a PCAP header to it.  */
443 	if (*mode == 'w') {
444 		sf_hdr.magic = TCPDUMP_MAGIC;
445 		sf_hdr.version_major = PCAP_VERSION_MAJOR;
446 		sf_hdr.version_minor = PCAP_VERSION_MINOR;
447 		sf_hdr.thiszone = 0;
448 		sf_hdr.snaplen = SNAPLEN;
449 		sf_hdr.sigfigs = 0;
450 		sf_hdr.linktype = DLT_LOOP;
451 
452 		fwrite((char *) &sf_hdr, sizeof sf_hdr, 1, packet_log);
453 		fflush(packet_log);
454 	}
455 }
456 
457 void
458 log_packet_restart(char *newname)
459 {
460 	if (packet_log) {
461 		log_print("log_packet_restart: capture already active on "
462 		    "file \"%s\"", pcaplog_file);
463 		return;
464 	}
465 	if (newname)
466 		log_packet_init(newname);
467 	else if (!pcaplog_file)
468 		log_packet_init(PCAP_FILE_DEFAULT);
469 	else
470 		log_packet_init(pcaplog_file);
471 }
472 
473 void
474 log_packet_stop(void)
475 {
476 	/* Stop capture.  */
477 	if (packet_log) {
478 		fclose(packet_log);
479 		log_print("log_packet_stop: stopped capture");
480 	}
481 	packet_log = 0;
482 }
483 
484 void
485 log_packet_iov(struct sockaddr *src, struct sockaddr *dst, struct iovec *iov,
486     int iovcnt)
487 {
488 	struct isakmp_hdr *isakmphdr;
489 	struct packhdr  hdr;
490 	struct udphdr   udp;
491 	struct timeval  tv;
492 	int             off, datalen, hdrlen, i, add_espmarker = 0;
493 	const u_int32_t	espmarker = 0;
494 
495 	for (i = 0, datalen = 0; i < iovcnt; i++)
496 		datalen += iov[i].iov_len;
497 
498 	if (!packet_log || datalen > SNAPLEN)
499 		return;
500 
501 	/* copy packet into buffer */
502 	for (i = 0, off = 0; i < iovcnt; i++) {
503 		memcpy(packet_buf + off, iov[i].iov_base, iov[i].iov_len);
504 		off += iov[i].iov_len;
505 	}
506 
507 	bzero(&hdr, sizeof hdr);
508 	bzero(&udp, sizeof udp);
509 
510 	/* isakmp - turn off the encryption bit in the isakmp hdr */
511 	isakmphdr = (struct isakmp_hdr *) packet_buf;
512 	isakmphdr->flags &= ~(ISAKMP_FLAGS_ENC);
513 
514 	/* udp */
515 	udp.uh_sport = sockaddr_port(src);
516 	udp.uh_dport = sockaddr_port(dst);
517 	datalen += sizeof udp;
518 	if (ntohs(udp.uh_sport) == 4500 ||
519 	    ntohs(udp.uh_dport) == 4500) { /* XXX Quick and dirty */
520 		add_espmarker = 1;
521 		datalen += sizeof espmarker;
522 	}
523 	udp.uh_ulen = htons(datalen);
524 
525 	/* ip */
526 	hdr.sa_family = htonl(src->sa_family);
527 	switch (src->sa_family) {
528 	default:
529 		/* Assume IPv4. XXX Can 'default' ever happen here?  */
530 		hdr.sa_family = htonl(AF_INET);
531 		hdr.ip.ip4.ip_src.s_addr = 0x02020202;
532 		hdr.ip.ip4.ip_dst.s_addr = 0x01010101;
533 		/* The rest of the setup is common to AF_INET.  */
534 		goto setup_ip4;
535 
536 	case AF_INET:
537 		hdr.ip.ip4.ip_src.s_addr =
538 		    ((struct sockaddr_in *)src)->sin_addr.s_addr;
539 		hdr.ip.ip4.ip_dst.s_addr =
540 		    ((struct sockaddr_in *)dst)->sin_addr.s_addr;
541 
542 setup_ip4:
543 		hdrlen = sizeof hdr.ip.ip4;
544 		hdr.ip.ip4.ip_v = 0x4;
545 		hdr.ip.ip4.ip_hl = 0x5;
546 		hdr.ip.ip4.ip_p = IPPROTO_UDP;
547 		hdr.ip.ip4.ip_len = htons(datalen + hdrlen);
548 		/* Let's use the IP ID as a "packet counter".  */
549 		i = ntohs(hdr.ip.ip4.ip_id) + 1;
550 		hdr.ip.ip4.ip_id = htons(i);
551 		/* Calculate IP header checksum. */
552 		hdr.ip.ip4.ip_sum = in_cksum((u_int16_t *) & hdr.ip.ip4,
553 		    hdr.ip.ip4.ip_hl << 2);
554 		break;
555 
556 	case AF_INET6:
557 		hdrlen = sizeof(hdr.ip.ip6);
558 		hdr.ip.ip6.ip6_vfc = IPV6_VERSION;
559 		hdr.ip.ip6.ip6_nxt = IPPROTO_UDP;
560 		hdr.ip.ip6.ip6_plen = udp.uh_ulen;
561 		memcpy(&hdr.ip.ip6.ip6_src,
562 		    &((struct sockaddr_in6 *)src)->sin6_addr,
563 		    sizeof hdr.ip.ip6.ip6_src);
564 		memcpy(&hdr.ip.ip6.ip6_dst,
565 		    &((struct sockaddr_in6 *)dst)->sin6_addr,
566 		    sizeof hdr.ip.ip6.ip6_dst);
567 		break;
568 	}
569 
570 	/* Calculate UDP checksum.  */
571 	udp.uh_sum = udp_cksum(&hdr, &udp, (u_int16_t *) packet_buf);
572 	hdrlen += sizeof hdr.sa_family;
573 
574 	/* pcap file packet header */
575 	gettimeofday(&tv, 0);
576 	hdr.pcap.ts.tv_sec = tv.tv_sec;
577 	hdr.pcap.ts.tv_usec = tv.tv_usec;
578 	hdr.pcap.caplen = datalen + hdrlen;
579 	hdr.pcap.len = datalen + hdrlen;
580 
581 	hdrlen += sizeof(struct pcap_pkthdr);
582 	datalen -= sizeof(struct udphdr);
583 
584 	/* Write to pcap file.  */
585 	fwrite(&hdr, hdrlen, 1, packet_log);	/* pcap + IP */
586 	fwrite(&udp, sizeof(struct udphdr), 1, packet_log);	/* UDP */
587 	if (add_espmarker) {
588 		fwrite(&espmarker, sizeof espmarker, 1, packet_log);
589 		datalen -= sizeof espmarker;
590 	}
591 	fwrite(packet_buf, datalen, 1, packet_log);	/* IKE-data */
592 	fflush(packet_log);
593 }
594 
595 /* Copied from tcpdump/print-udp.c, mostly rewritten.  */
596 static int
597 udp_cksum(struct packhdr *hdr, const struct udphdr *u, u_int16_t *d)
598 {
599 	struct ip	*ip4;
600 	struct ip6_hdr	*ip6;
601 	int	i, hdrlen, tlen = ntohs(u->uh_ulen) - sizeof(struct udphdr);
602 
603 	union phu {
604 		struct ip4pseudo {
605 			struct in_addr  src;
606 			struct in_addr  dst;
607 			u_int8_t        z;
608 			u_int8_t        proto;
609 			u_int16_t       len;
610 		} ip4p;
611 		struct ip6pseudo {
612 			struct in6_addr src;
613 			struct in6_addr dst;
614 			u_int32_t       plen;
615 			u_int16_t       z0;
616 			u_int8_t        z1;
617 			u_int8_t        nxt;
618 		} ip6p;
619 		u_int16_t       pa[20];
620 	} phu;
621 	const u_int16_t *sp;
622 	u_int32_t       sum;
623 
624 	/* Setup pseudoheader.  */
625 	bzero(phu.pa, sizeof phu);
626 	switch (ntohl(hdr->sa_family)) {
627 	case AF_INET:
628 		ip4 = &hdr->ip.ip4;
629 		memcpy(&phu.ip4p.src, &ip4->ip_src, sizeof(struct in_addr));
630 		memcpy(&phu.ip4p.dst, &ip4->ip_dst, sizeof(struct in_addr));
631 		phu.ip4p.proto = ip4->ip_p;
632 		phu.ip4p.len = u->uh_ulen;
633 		hdrlen = sizeof phu.ip4p;
634 		break;
635 
636 	case AF_INET6:
637 		ip6 = &hdr->ip.ip6;
638 		memcpy(&phu.ip6p.src, &ip6->ip6_src, sizeof(phu.ip6p.src));
639 		memcpy(&phu.ip6p.dst, &ip6->ip6_dst, sizeof(phu.ip6p.dst));
640 		phu.ip6p.plen = u->uh_ulen;
641 		phu.ip6p.nxt = ip6->ip6_nxt;
642 		hdrlen = sizeof phu.ip6p;
643 		break;
644 
645 	default:
646 		return 0;
647 	}
648 
649 	/* IPv6 wants a 0xFFFF checksum "on error", not 0x0.  */
650 	if (tlen < 0)
651 		return (ntohl(hdr->sa_family) == AF_INET ? 0 : 0xFFFF);
652 
653 	sum = 0;
654 	for (i = 0; i < hdrlen; i += 2)
655 		sum += phu.pa[i / 2];
656 
657 	sp = (const u_int16_t *)u;
658 	for (i = 0; i < (int)sizeof(struct udphdr); i += 2)
659 		sum += *sp++;
660 
661 	sp = d;
662 	for (i = 0; i < (tlen & ~1); i += 2)
663 		sum += *sp++;
664 
665 	if (tlen & 1)
666 		sum += htons((*(const char *)sp) << 8);
667 
668 	while (sum > 0xffff)
669 		sum = (sum & 0xffff) + (sum >> 16);
670 	sum = ~sum & 0xffff;
671 
672 	return sum;
673 }
674 
675 /* Copied from tcpdump/print-ip.c, modified.  */
676 static u_int16_t
677 in_cksum(const u_int16_t *w, int len)
678 {
679 	int		nleft = len, sum = 0;
680 	u_int16_t       answer;
681 
682 	while (nleft > 1) {
683 		sum += *w++;
684 		nleft -= 2;
685 	}
686 	if (nleft == 1)
687 		sum += htons(*(const u_char *)w << 8);
688 
689 	sum = (sum >> 16) + (sum & 0xffff);	/* add hi 16 to low 16 */
690 	sum += (sum >> 16);	/* add carry */
691 	answer = ~sum;		/* truncate to 16 bits */
692 	return answer;
693 }
694