Pre-2.0 release, MFC 63 - HAMMER I/O error handling and catastrophic
[dragonfly.git] / usr.sbin / rarpd / rarpd.c
blob5eb89717536998ffa63299eceb5d1760b9198498
1 /*
2 * Copyright (c) 1990, 1991, 1992, 1993, 1996
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that: (1) source code distributions
7 * retain the above copyright notice and this paragraph in its entirety, (2)
8 * distributions including binary code include the above copyright notice and
9 * this paragraph in its entirety in the documentation or other materials
10 * provided with the distribution, and (3) all advertising materials mentioning
11 * features or use of this software display the following acknowledgement:
12 * ``This product includes software developed by the University of California,
13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14 * the University nor the names of its contributors may be used to endorse
15 * or promote products derived from this software without specific prior
16 * written permission.
17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
21 * @(#) Copyright (c) 1990, 1991, 1992, 1993, 1996 The Regents of the University of California. All rights reserved.
22 * $FreeBSD: src/usr.sbin/rarpd/rarpd.c,v 1.23.2.4 2002/12/01 19:19:34 dwmalone Exp $
23 * $DragonFly: src/usr.sbin/rarpd/rarpd.c,v 1.4 2004/12/18 22:48:05 swildner Exp $
27 * rarpd - Reverse ARP Daemon
29 * Usage: rarpd -a [ -dfsv ] [-t directory] [ hostname ]
30 * rarpd [ -dfsv ] [-t directory] interface [ hostname ]
32 * 'hostname' is optional solely for backwards compatibility with Sun's rarpd.
33 * Currently, the argument is ignored.
35 #include <sys/param.h>
36 #include <sys/file.h>
37 #include <sys/ioctl.h>
38 #include <sys/socket.h>
39 #include <sys/time.h>
41 #include <net/bpf.h>
42 #include <net/ethernet.h>
43 #include <net/if.h>
44 #include <net/if_types.h>
45 #include <net/if_dl.h>
46 #include <net/route.h>
48 #include <netinet/in.h>
49 #include <netinet/if_ether.h>
51 #include <arpa/inet.h>
53 #include <errno.h>
54 #include <netdb.h>
55 #include <stdarg.h>
56 #include <stdio.h>
57 #include <string.h>
58 #include <syslog.h>
59 #include <stdlib.h>
60 #include <unistd.h>
62 #if defined(SUNOS4) || defined(__DragonFly__) /* XXX */
63 #define HAVE_DIRENT_H
64 #endif
66 #ifdef HAVE_DIRENT_H
67 #include <dirent.h>
68 #else
69 #include <sys/dir.h>
70 #endif
72 /* Cast a struct sockaddr to a structaddr_in */
73 #define SATOSIN(sa) ((struct sockaddr_in *)(sa))
75 #ifndef TFTP_DIR
76 #define TFTP_DIR "/tftpboot"
77 #endif
79 #if BSD >= 199200
80 #define ARPSECS (20 * 60) /* as per code in netinet/if_ether.c */
81 #define REVARP_REQUEST ARPOP_REVREQUEST
82 #define REVARP_REPLY ARPOP_REVREPLY
83 #endif
85 #ifndef ETHERTYPE_REVARP
86 #define ETHERTYPE_REVARP 0x8035
87 #define REVARP_REQUEST 3
88 #define REVARP_REPLY 4
89 #endif
92 * Map field names in ether_arp struct. What a pain in the neck.
94 #ifdef SUNOS3
95 #undef arp_sha
96 #undef arp_spa
97 #undef arp_tha
98 #undef arp_tpa
99 #define arp_sha arp_xsha
100 #define arp_spa arp_xspa
101 #define arp_tha arp_xtha
102 #define arp_tpa arp_xtpa
103 #endif
106 * The structure for each interface.
108 struct if_info {
109 struct if_info *ii_next;
110 int ii_fd; /* BPF file descriptor */
111 u_long ii_ipaddr; /* IP address of this interface */
112 u_long ii_netmask; /* subnet or net mask */
113 u_char ii_eaddr[6]; /* Ethernet address of this interface */
114 char ii_ifname[sizeof(((struct ifreq *)0)->ifr_name) + 1];
118 * The list of all interfaces that are being listened to. rarp_loop()
119 * "selects" on the descriptors in this list.
121 struct if_info *iflist;
123 int verbose; /* verbose messages */
124 int s; /* inet datagram socket */
125 const char *tftp_dir = TFTP_DIR; /* tftp directory */
127 int dflag; /* messages to stdout/stderr, not syslog(3) */
128 int sflag; /* ignore /tftpboot */
130 static u_char zero[6];
132 static int bpf_open(void);
133 static u_long choose_ipaddr(u_long **, u_long, u_long);
134 static char *eatoa(u_char *);
135 static int expand_syslog_m(const char *fmt, char **newfmt);
136 static void init(char *);
137 static void init_one(struct ifreq *, char *);
138 static char *intoa(u_long);
139 static u_long ipaddrtonetmask(u_long);
140 static void logmsg(int, const char *, ...) __printflike(2, 3);
141 static int rarp_bootable(u_long);
142 static int rarp_check(u_char *, u_int);
143 static void rarp_loop(void);
144 static int rarp_open(char *);
145 static void rarp_process(struct if_info *, u_char *, u_int);
146 static void rarp_reply(struct if_info *, struct ether_header *,
147 u_long, u_int);
148 static void update_arptab(u_char *, u_long);
149 static void usage(void);
152 main(int argc, char *argv[])
154 int op;
155 char *ifname, *hostname, *name;
157 int aflag = 0; /* listen on "all" interfaces */
158 int fflag = 0; /* don't fork */
160 if ((name = strrchr(argv[0], '/')) != NULL)
161 ++name;
162 else
163 name = argv[0];
164 if (*name == '-')
165 ++name;
168 * All error reporting is done through syslog, unless -d is specified
170 openlog(name, LOG_PID | LOG_CONS, LOG_DAEMON);
172 opterr = 0;
173 while ((op = getopt(argc, argv, "adfst:v")) != -1) {
174 switch (op) {
175 case 'a':
176 ++aflag;
177 break;
179 case 'd':
180 ++dflag;
181 break;
183 case 'f':
184 ++fflag;
185 break;
187 case 's':
188 ++sflag;
189 break;
191 case 't':
192 tftp_dir = optarg;
193 break;
195 case 'v':
196 ++verbose;
197 break;
199 default:
200 usage();
201 /* NOTREACHED */
204 ifname = argv[optind++];
205 hostname = ifname ? argv[optind] : NULL;
206 if ((aflag && ifname) || (!aflag && ifname == NULL))
207 usage();
209 if (aflag)
210 init(NULL);
211 else
212 init(ifname);
214 if (!fflag) {
215 if (daemon(0,0)) {
216 logmsg(LOG_ERR, "cannot fork");
217 exit(1);
220 rarp_loop();
221 return(0);
225 * Add to the interface list.
227 void
228 init_one(struct ifreq *ifrp, char *target)
230 struct if_info *ii;
231 struct sockaddr_dl *ll;
232 int family;
233 struct ifreq ifr;
235 family = ifrp->ifr_addr.sa_family;
236 switch (family) {
238 case AF_INET:
239 #if BSD >= 199100
240 case AF_LINK:
241 #endif
242 strncpy(ifr.ifr_name, ifrp->ifr_name, sizeof(ifrp->ifr_name));
243 if (ioctl(s, SIOCGIFFLAGS, (char *)&ifr) == -1) {
244 logmsg(LOG_ERR,
245 "SIOCGIFFLAGS: %.*s: %m",
246 (int)sizeof(ifrp->ifr_name), ifrp->ifr_name);
247 exit(1);
249 if ((ifr.ifr_flags & IFF_UP) == 0 ||
250 (ifr.ifr_flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) != 0)
251 return;
252 break;
255 default:
256 return;
259 /* Don't bother going any further if not the target interface */
260 if (target != NULL &&
261 strncmp(ifrp->ifr_name, target, sizeof(ifrp->ifr_name)) != 0)
262 return;
264 /* Look for interface in list */
265 for (ii = iflist; ii != NULL; ii = ii->ii_next)
266 if (strncmp(ifrp->ifr_name, ii->ii_ifname,
267 sizeof(ifrp->ifr_name)) == 0)
268 break;
270 /* Allocate a new one if not found */
271 if (ii == NULL) {
272 ii = (struct if_info *)malloc(sizeof(*ii));
273 if (ii == NULL) {
274 logmsg(LOG_ERR, "malloc: %m");
275 exit(1);
277 bzero(ii, sizeof(*ii));
278 ii->ii_fd = -1;
279 strncpy(ii->ii_ifname, ifrp->ifr_name, sizeof(ifrp->ifr_name));
280 ii->ii_ifname[sizeof(ii->ii_ifname) - 1] = '\0';
281 ii->ii_next = iflist;
282 iflist = ii;
285 switch (family) {
287 case AF_INET:
288 if (ioctl(s, SIOCGIFADDR, (char *)&ifr) == -1) {
289 logmsg(LOG_ERR, "ipaddr SIOCGIFADDR: %s: %m",
290 ii->ii_ifname);
291 exit(1);
293 ii->ii_ipaddr = SATOSIN(&ifr.ifr_addr)->sin_addr.s_addr;
294 if (ioctl(s, SIOCGIFNETMASK, (char *)&ifr) == -1) {
295 logmsg(LOG_ERR, "SIOCGIFNETMASK: %m");
296 exit(1);
298 ii->ii_netmask = SATOSIN(&ifr.ifr_addr)->sin_addr.s_addr;
299 if (ii->ii_netmask == 0)
300 ii->ii_netmask = ipaddrtonetmask(ii->ii_ipaddr);
301 if (ii->ii_fd < 0) {
302 ii->ii_fd = rarp_open(ii->ii_ifname);
303 #if BSD < 199100
304 /* Use BPF descriptor to get ethernet address. */
305 if (ioctl(ii->ii_fd, SIOCGIFADDR, (char *)&ifr) == -1) {
306 logmsg(LOG_ERR, "eaddr SIOCGIFADDR: %s: %m",
307 ii->ii_ifname);
308 exit(1);
310 bcopy(&ifr.ifr_addr.sa_data[0], ii->ii_eaddr, 6);
311 #endif
313 break;
315 #if BSD >= 199100
316 case AF_LINK:
317 ll = (struct sockaddr_dl *)&ifrp->ifr_addr;
318 if (ll->sdl_type == IFT_ETHER)
319 bcopy(LLADDR(ll), ii->ii_eaddr, 6);
320 break;
321 #endif
325 * Initialize all "candidate" interfaces that are in the system
326 * configuration list. A "candidate" is up, not loopback and not
327 * point to point.
329 void
330 init(char *target)
332 u_int n;
333 struct ifreq *ifrp, *ifend;
334 struct if_info *ii, *nii, *lii;
335 struct ifconf ifc;
336 struct ifreq ibuf[16];
338 if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
339 logmsg(LOG_ERR, "socket: %m");
340 exit(1);
342 ifc.ifc_len = sizeof ibuf;
343 ifc.ifc_buf = (caddr_t)ibuf;
344 if ((ioctl(s, SIOCGIFCONF, (char *)&ifc) == -1) ||
345 ((u_int)ifc.ifc_len < sizeof(struct ifreq))) {
346 logmsg(LOG_ERR, "SIOCGIFCONF: %m");
347 exit(1);
349 ifrp = ibuf;
350 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len);
351 while (ifrp < ifend) {
352 init_one(ifrp, target);
354 #if BSD >= 199100
355 n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name);
356 if (n < sizeof(*ifrp))
357 n = sizeof(*ifrp);
358 ifrp = (struct ifreq *)((char *)ifrp + n);
359 #else
360 ++ifrp;
361 #endif
364 /* Throw away incomplete interfaces */
365 lii = NULL;
366 for (ii = iflist; ii != NULL; ii = nii) {
367 nii = ii->ii_next;
368 if (ii->ii_ipaddr == 0 ||
369 bcmp(ii->ii_eaddr, zero, 6) == 0) {
370 if (lii == NULL)
371 iflist = nii;
372 else
373 lii->ii_next = nii;
374 if (ii->ii_fd >= 0)
375 close(ii->ii_fd);
376 free(ii);
377 continue;
379 lii = ii;
382 /* Verbose stuff */
383 if (verbose)
384 for (ii = iflist; ii != NULL; ii = ii->ii_next)
385 logmsg(LOG_DEBUG, "%s %s 0x%08lx %s",
386 ii->ii_ifname, intoa(ntohl(ii->ii_ipaddr)),
387 (u_long)ntohl(ii->ii_netmask), eatoa(ii->ii_eaddr));
390 void
391 usage(void)
393 fprintf(stderr, "usage: rarpd [-adfsv] [-t directory] [interface]\n");
394 exit(1);
398 bpf_open(void)
400 int fd;
401 int n = 0;
402 char device[sizeof "/dev/bpf000"];
405 * Go through all the minors and find one that isn't in use.
407 do {
408 sprintf(device, "/dev/bpf%d", n++);
409 fd = open(device, O_RDWR);
410 } while ((fd == -1) && (errno == EBUSY));
412 if (fd == -1) {
413 logmsg(LOG_ERR, "%s: %m", device);
414 exit(1);
416 return fd;
420 * Open a BPF file and attach it to the interface named 'device'.
421 * Set immediate mode, and set a filter that accepts only RARP requests.
424 rarp_open(char *device)
426 int fd;
427 struct ifreq ifr;
428 u_int dlt;
429 int immediate;
431 static struct bpf_insn insns[] = {
432 BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 12),
433 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, ETHERTYPE_REVARP, 0, 3),
434 BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 20),
435 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, REVARP_REQUEST, 0, 1),
436 BPF_STMT(BPF_RET|BPF_K, sizeof(struct ether_arp) +
437 sizeof(struct ether_header)),
438 BPF_STMT(BPF_RET|BPF_K, 0),
440 static struct bpf_program filter = {
441 sizeof insns / sizeof(insns[0]),
442 insns
445 fd = bpf_open();
447 * Set immediate mode so packets are processed as they arrive.
449 immediate = 1;
450 if (ioctl(fd, BIOCIMMEDIATE, &immediate) == -1) {
451 logmsg(LOG_ERR, "BIOCIMMEDIATE: %m");
452 exit(1);
454 strncpy(ifr.ifr_name, device, sizeof ifr.ifr_name);
455 if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) == -1) {
456 logmsg(LOG_ERR, "BIOCSETIF: %m");
457 exit(1);
460 * Check that the data link layer is an Ethernet; this code won't
461 * work with anything else.
463 if (ioctl(fd, BIOCGDLT, (caddr_t)&dlt) == -1) {
464 logmsg(LOG_ERR, "BIOCGDLT: %m");
465 exit(1);
467 if (dlt != DLT_EN10MB) {
468 logmsg(LOG_ERR, "%s is not an ethernet", device);
469 exit(1);
472 * Set filter program.
474 if (ioctl(fd, BIOCSETF, (caddr_t)&filter) == -1) {
475 logmsg(LOG_ERR, "BIOCSETF: %m");
476 exit(1);
478 return fd;
482 * Perform various sanity checks on the RARP request packet. Return
483 * false on failure and log the reason.
486 rarp_check(u_char *p, u_int len)
488 struct ether_header *ep = (struct ether_header *)p;
489 struct ether_arp *ap = (struct ether_arp *)(p + sizeof(*ep));
491 if (len < sizeof(*ep) + sizeof(*ap)) {
492 logmsg(LOG_ERR, "truncated request, got %u, expected %lu",
493 len, (u_long)(sizeof(*ep) + sizeof(*ap)));
494 return 0;
497 * XXX This test might be better off broken out...
499 if (ntohs(ep->ether_type) != ETHERTYPE_REVARP ||
500 ntohs(ap->arp_hrd) != ARPHRD_ETHER ||
501 ntohs(ap->arp_op) != REVARP_REQUEST ||
502 ntohs(ap->arp_pro) != ETHERTYPE_IP ||
503 ap->arp_hln != 6 || ap->arp_pln != 4) {
504 logmsg(LOG_DEBUG, "request fails sanity check");
505 return 0;
507 if (bcmp((char *)&ep->ether_shost, (char *)&ap->arp_sha, 6) != 0) {
508 logmsg(LOG_DEBUG, "ether/arp sender address mismatch");
509 return 0;
511 if (bcmp((char *)&ap->arp_sha, (char *)&ap->arp_tha, 6) != 0) {
512 logmsg(LOG_DEBUG, "ether/arp target address mismatch");
513 return 0;
515 return 1;
518 #ifndef FD_SETSIZE
519 #define FD_SET(n, fdp) ((fdp)->fds_bits[0] |= (1 << (n)))
520 #define FD_ISSET(n, fdp) ((fdp)->fds_bits[0] & (1 << (n)))
521 #define FD_ZERO(fdp) ((fdp)->fds_bits[0] = 0)
522 #endif
525 * Loop indefinitely listening for RARP requests on the
526 * interfaces in 'iflist'.
528 void
529 rarp_loop(void)
531 u_char *buf, *bp, *ep;
532 int cc, fd;
533 fd_set fds, listeners;
534 int bufsize, maxfd = 0;
535 struct if_info *ii;
537 if (iflist == NULL) {
538 logmsg(LOG_ERR, "no interfaces");
539 exit(1);
541 if (ioctl(iflist->ii_fd, BIOCGBLEN, (caddr_t)&bufsize) == -1) {
542 logmsg(LOG_ERR, "BIOCGBLEN: %m");
543 exit(1);
545 buf = malloc(bufsize);
546 if (buf == NULL) {
547 logmsg(LOG_ERR, "malloc: %m");
548 exit(1);
551 while (1) {
553 * Find the highest numbered file descriptor for select().
554 * Initialize the set of descriptors to listen to.
556 FD_ZERO(&fds);
557 for (ii = iflist; ii != NULL; ii = ii->ii_next) {
558 FD_SET(ii->ii_fd, &fds);
559 if (ii->ii_fd > maxfd)
560 maxfd = ii->ii_fd;
562 listeners = fds;
563 if (select(maxfd + 1, &listeners, NULL, NULL, NULL) == -1) {
564 /* Don't choke when we get ptraced */
565 if (errno == EINTR)
566 continue;
567 logmsg(LOG_ERR, "select: %m");
568 exit(1);
570 for (ii = iflist; ii != NULL; ii = ii->ii_next) {
571 fd = ii->ii_fd;
572 if (!FD_ISSET(fd, &listeners))
573 continue;
574 again:
575 cc = read(fd, (char *)buf, bufsize);
576 /* Don't choke when we get ptraced */
577 if ((cc == -1) && (errno == EINTR))
578 goto again;
579 #if defined(SUNOS3) || defined(SUNOS4)
581 * Due to a SunOS bug, after 2^31 bytes, the
582 * file offset overflows and read fails with
583 * EINVAL. The lseek() to 0 will fix things.
585 if (cc == -1) {
586 if (errno == EINVAL &&
587 (long)(tell(fd) + bufsize) < 0) {
588 lseek(fd, 0, 0);
589 goto again;
591 logmsg(LOG_ERR, "read: %m");
592 exit(1);
594 #endif
596 /* Loop through the packet(s) */
597 #define bhp ((struct bpf_hdr *)bp)
598 bp = buf;
599 ep = bp + cc;
600 while (bp < ep) {
601 u_int caplen, hdrlen;
603 caplen = bhp->bh_caplen;
604 hdrlen = bhp->bh_hdrlen;
605 if (rarp_check(bp + hdrlen, caplen))
606 rarp_process(ii, bp + hdrlen, caplen);
607 bp += BPF_WORDALIGN(hdrlen + caplen);
611 #undef bhp
615 * True if this server can boot the host whose IP address is 'addr'.
616 * This check is made by looking in the tftp directory for the
617 * configuration file.
620 rarp_bootable(u_long addr)
622 #ifdef HAVE_DIRENT_H
623 struct dirent *dent;
624 #else
625 struct direct *dent;
626 #endif
627 DIR *d;
628 char ipname[9];
629 static DIR *dd = NULL;
631 sprintf(ipname, "%08lX", (u_long)ntohl(addr));
634 * If directory is already open, rewind it. Otherwise, open it.
636 if ((d = dd) != NULL)
637 rewinddir(d);
638 else {
639 if (chdir(tftp_dir) == -1) {
640 logmsg(LOG_ERR, "chdir: %s: %m", tftp_dir);
641 exit(1);
643 d = opendir(".");
644 if (d == NULL) {
645 logmsg(LOG_ERR, "opendir: %m");
646 exit(1);
648 dd = d;
650 while ((dent = readdir(d)) != NULL)
651 if (strncmp(dent->d_name, ipname, 8) == 0)
652 return 1;
653 return 0;
657 * Given a list of IP addresses, 'alist', return the first address that
658 * is on network 'net'; 'netmask' is a mask indicating the network portion
659 * of the address.
661 u_long
662 choose_ipaddr(u_long **alist, u_long net, u_long netmask)
664 for (; *alist; ++alist)
665 if ((**alist & netmask) == net)
666 return **alist;
667 return 0;
671 * Answer the RARP request in 'pkt', on the interface 'ii'. 'pkt' has
672 * already been checked for validity. The reply is overlaid on the request.
674 void
675 rarp_process(struct if_info *ii, u_char *pkt, u_int len)
677 struct ether_header *ep;
678 struct hostent *hp;
679 u_long target_ipaddr;
680 char ename[256];
682 ep = (struct ether_header *)pkt;
683 /* should this be arp_tha? */
684 if (ether_ntohost(ename, (struct ether_addr *)&ep->ether_shost) != 0) {
685 logmsg(LOG_ERR, "cannot map %s to name",
686 eatoa(ep->ether_shost));
687 return;
690 if ((hp = gethostbyname(ename)) == NULL) {
691 logmsg(LOG_ERR, "cannot map %s to IP address", ename);
692 return;
696 * Choose correct address from list.
698 if (hp->h_addrtype != AF_INET) {
699 logmsg(LOG_ERR, "cannot handle non IP addresses for %s",
700 ename);
701 return;
703 target_ipaddr = choose_ipaddr((u_long **)hp->h_addr_list,
704 ii->ii_ipaddr & ii->ii_netmask,
705 ii->ii_netmask);
706 if (target_ipaddr == 0) {
707 logmsg(LOG_ERR, "cannot find %s on net %s",
708 ename, intoa(ntohl(ii->ii_ipaddr & ii->ii_netmask)));
709 return;
711 if (sflag || rarp_bootable(target_ipaddr))
712 rarp_reply(ii, ep, target_ipaddr, len);
713 else if (verbose > 1)
714 logmsg(LOG_INFO, "%s %s at %s DENIED (not bootable)",
715 ii->ii_ifname,
716 eatoa(ep->ether_shost),
717 intoa(ntohl(target_ipaddr)));
721 * Poke the kernel arp tables with the ethernet/ip address combinataion
722 * given. When processing a reply, we must do this so that the booting
723 * host (i.e. the guy running rarpd), won't try to ARP for the hardware
724 * address of the guy being booted (he cannot answer the ARP).
726 #if BSD >= 199200
727 struct sockaddr_inarp sin_inarp = {
728 sizeof(struct sockaddr_inarp), AF_INET, 0,
729 {0},
730 {0},
731 0, 0
733 struct sockaddr_dl sin_dl = {
734 sizeof(struct sockaddr_dl), AF_LINK, 0, IFT_ETHER, 0, 6,
735 0, ""
737 struct {
738 struct rt_msghdr rthdr;
739 char rtspace[512];
740 } rtmsg;
742 void
743 update_arptab(u_char *ep, u_long ipaddr)
745 int cc;
746 struct sockaddr_inarp *ar, *ar2;
747 struct sockaddr_dl *ll, *ll2;
748 struct rt_msghdr *rt;
749 int xtype, xindex;
750 static pid_t pid;
751 int r;
752 static int seq;
754 r = socket(PF_ROUTE, SOCK_RAW, 0);
755 if (r == -1) {
756 logmsg(LOG_ERR, "raw route socket: %m");
757 exit(1);
759 pid = getpid();
761 ar = &sin_inarp;
762 ar->sin_addr.s_addr = ipaddr;
763 ll = &sin_dl;
764 bcopy(ep, LLADDR(ll), 6);
766 /* Get the type and interface index */
767 rt = &rtmsg.rthdr;
768 bzero(rt, sizeof(rtmsg));
769 rt->rtm_version = RTM_VERSION;
770 rt->rtm_addrs = RTA_DST;
771 rt->rtm_type = RTM_GET;
772 rt->rtm_seq = ++seq;
773 ar2 = (struct sockaddr_inarp *)rtmsg.rtspace;
774 bcopy(ar, ar2, sizeof(*ar));
775 rt->rtm_msglen = sizeof(*rt) + sizeof(*ar);
776 errno = 0;
777 if ((write(r, rt, rt->rtm_msglen) == -1) && (errno != ESRCH)) {
778 logmsg(LOG_ERR, "rtmsg get write: %m");
779 close(r);
780 return;
782 do {
783 cc = read(r, rt, sizeof(rtmsg));
784 } while (cc > 0 && (rt->rtm_seq != seq || rt->rtm_pid != pid));
785 if (cc == -1) {
786 logmsg(LOG_ERR, "rtmsg get read: %m");
787 close(r);
788 return;
790 ll2 = (struct sockaddr_dl *)((u_char *)ar2 + ar2->sin_len);
791 if (ll2->sdl_family != AF_LINK) {
793 * XXX I think this means the ip address is not on a
794 * directly connected network (the family is AF_INET in
795 * this case).
797 logmsg(LOG_ERR, "bogus link family (%d) wrong net for %08lX?\n",
798 ll2->sdl_family, ipaddr);
799 close(r);
800 return;
802 xtype = ll2->sdl_type;
803 xindex = ll2->sdl_index;
805 /* Set the new arp entry */
806 bzero(rt, sizeof(rtmsg));
807 rt->rtm_version = RTM_VERSION;
808 rt->rtm_addrs = RTA_DST | RTA_GATEWAY;
809 rt->rtm_inits = RTV_EXPIRE;
810 rt->rtm_rmx.rmx_expire = time(0) + ARPSECS;
811 rt->rtm_flags = RTF_HOST | RTF_STATIC;
812 rt->rtm_type = RTM_ADD;
813 rt->rtm_seq = ++seq;
815 bcopy(ar, ar2, sizeof(*ar));
817 ll2 = (struct sockaddr_dl *)((u_char *)ar2 + sizeof(*ar2));
818 bcopy(ll, ll2, sizeof(*ll));
819 ll2->sdl_type = xtype;
820 ll2->sdl_index = xindex;
822 rt->rtm_msglen = sizeof(*rt) + sizeof(*ar2) + sizeof(*ll2);
823 errno = 0;
824 if ((write(r, rt, rt->rtm_msglen) == -1) && (errno != EEXIST)) {
825 logmsg(LOG_ERR, "rtmsg add write: %m");
826 close(r);
827 return;
829 do {
830 cc = read(r, rt, sizeof(rtmsg));
831 } while (cc > 0 && (rt->rtm_seq != seq || rt->rtm_pid != pid));
832 close(r);
833 if (cc == -1) {
834 logmsg(LOG_ERR, "rtmsg add read: %m");
835 return;
838 #else
839 void
840 update_arptab(u_char *ep, u_long ipaddr)
842 struct arpreq request;
843 struct sockaddr_in *sin;
845 request.arp_flags = 0;
846 sin = (struct sockaddr_in *)&request.arp_pa;
847 sin->sin_family = AF_INET;
848 sin->sin_addr.s_addr = ipaddr;
849 request.arp_ha.sa_family = AF_UNSPEC;
850 bcopy((char *)ep, (char *)request.arp_ha.sa_data, 6);
852 if (ioctl(s, SIOCSARP, (caddr_t)&request) == -1)
853 logmsg(LOG_ERR, "SIOCSARP: %m");
855 #endif
858 * Build a reverse ARP packet and sent it out on the interface.
859 * 'ep' points to a valid REVARP_REQUEST. The REVARP_REPLY is built
860 * on top of the request, then written to the network.
862 * RFC 903 defines the ether_arp fields as follows. The following comments
863 * are taken (more or less) straight from this document.
865 * REVARP_REQUEST
867 * arp_sha is the hardware address of the sender of the packet.
868 * arp_spa is undefined.
869 * arp_tha is the 'target' hardware address.
870 * In the case where the sender wishes to determine his own
871 * protocol address, this, like arp_sha, will be the hardware
872 * address of the sender.
873 * arp_tpa is undefined.
875 * REVARP_REPLY
877 * arp_sha is the hardware address of the responder (the sender of the
878 * reply packet).
879 * arp_spa is the protocol address of the responder (see the note below).
880 * arp_tha is the hardware address of the target, and should be the same as
881 * that which was given in the request.
882 * arp_tpa is the protocol address of the target, that is, the desired address.
884 * Note that the requirement that arp_spa be filled in with the responder's
885 * protocol is purely for convenience. For instance, if a system were to use
886 * both ARP and RARP, then the inclusion of the valid protocol-hardware
887 * address pair (arp_spa, arp_sha) may eliminate the need for a subsequent
888 * ARP request.
890 void
891 rarp_reply(struct if_info *ii, struct ether_header *ep, u_long ipaddr,
892 u_int len)
894 u_int n;
895 struct ether_arp *ap = (struct ether_arp *)(ep + 1);
897 update_arptab((u_char *)&ap->arp_sha, ipaddr);
900 * Build the rarp reply by modifying the rarp request in place.
902 ap->arp_op = htons(REVARP_REPLY);
904 #ifdef BROKEN_BPF
905 ep->ether_type = ETHERTYPE_REVARP;
906 #endif
907 bcopy((char *)&ap->arp_sha, (char *)&ep->ether_dhost, 6);
908 bcopy((char *)ii->ii_eaddr, (char *)&ep->ether_shost, 6);
909 bcopy((char *)ii->ii_eaddr, (char *)&ap->arp_sha, 6);
911 bcopy((char *)&ipaddr, (char *)ap->arp_tpa, 4);
912 /* Target hardware is unchanged. */
913 bcopy((char *)&ii->ii_ipaddr, (char *)ap->arp_spa, 4);
915 /* Zero possible garbage after packet. */
916 bzero((char *)ep + (sizeof(*ep) + sizeof(*ap)),
917 len - (sizeof(*ep) + sizeof(*ap)));
918 n = write(ii->ii_fd, (char *)ep, len);
919 if (n != len)
920 logmsg(LOG_ERR, "write: only %d of %d bytes written", n, len);
921 if (verbose)
922 logmsg(LOG_INFO, "%s %s at %s REPLIED", ii->ii_ifname,
923 eatoa(ap->arp_tha),
924 intoa(ntohl(ipaddr)));
928 * Get the netmask of an IP address. This routine is used if
929 * SIOCGIFNETMASK doesn't work.
931 u_long
932 ipaddrtonetmask(u_long addr)
934 addr = ntohl(addr);
935 if (IN_CLASSA(addr))
936 return htonl(IN_CLASSA_NET);
937 if (IN_CLASSB(addr))
938 return htonl(IN_CLASSB_NET);
939 if (IN_CLASSC(addr))
940 return htonl(IN_CLASSC_NET);
941 logmsg(LOG_DEBUG, "unknown IP address class: %08lX", addr);
942 return htonl(0xffffffff);
946 * A faster replacement for inet_ntoa().
948 char *
949 intoa(u_long addr)
951 char *cp;
952 u_int byte;
953 int n;
954 static char buf[sizeof(".xxx.xxx.xxx.xxx")];
956 cp = &buf[sizeof buf];
957 *--cp = '\0';
959 n = 4;
960 do {
961 byte = addr & 0xff;
962 *--cp = byte % 10 + '0';
963 byte /= 10;
964 if (byte > 0) {
965 *--cp = byte % 10 + '0';
966 byte /= 10;
967 if (byte > 0)
968 *--cp = byte + '0';
970 *--cp = '.';
971 addr >>= 8;
972 } while (--n > 0);
974 return cp + 1;
977 char *
978 eatoa(u_char *ea)
980 static char buf[sizeof("xx:xx:xx:xx:xx:xx")];
982 sprintf(buf, "%x:%x:%x:%x:%x:%x",
983 ea[0], ea[1], ea[2], ea[3], ea[4], ea[5]);
984 return (buf);
987 void
988 logmsg(int pri, const char *fmt, ...)
990 va_list v;
991 FILE *fp;
992 char *newfmt;
994 va_start(v, fmt);
995 if (dflag) {
996 if (pri == LOG_ERR)
997 fp = stderr;
998 else
999 fp = stdout;
1000 if (expand_syslog_m(fmt, &newfmt) == -1) {
1001 vfprintf(fp, fmt, v);
1002 } else {
1003 vfprintf(fp, newfmt, v);
1004 free(newfmt);
1006 fputs("\n", fp);
1007 fflush(fp);
1008 } else {
1009 vsyslog(pri, fmt, v);
1011 va_end(v);
1015 expand_syslog_m(const char *fmt, char **newfmt) {
1016 const char *str, *m;
1017 char *p, *np;
1019 p = strdup("");
1020 str = fmt;
1021 while ((m = strstr(str, "%m")) != NULL) {
1022 asprintf(&np, "%s%.*s%s", p, (int)(m - str),
1023 str, strerror(errno));
1024 free(p);
1025 if (np == NULL) {
1026 errno = ENOMEM;
1027 return (-1);
1029 p = np;
1030 str = m + 2;
1033 if (*str != '\0') {
1034 asprintf(&np, "%s%s", p, str);
1035 free(p);
1036 if (np == NULL) {
1037 errno = ENOMEM;
1038 return (-1);
1040 p = np;
1043 *newfmt = p;
1044 return (0);