1130b656e5
This will make a number of things easier in the future, as well as (finally!) avoiding the Id-smashing problem which has plagued developers for so long. Boy, I'm glad we're not using sup anymore. This update would have been insane otherwise.
1010 lines
23 KiB
C
1010 lines
23 KiB
C
/*
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* Copyright (c) 1990, 1991, 1992, 1993, 1996
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that: (1) source code distributions
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* retain the above copyright notice and this paragraph in its entirety, (2)
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* distributions including binary code include the above copyright notice and
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* this paragraph in its entirety in the documentation or other materials
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* provided with the distribution, and (3) all advertising materials mentioning
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* features or use of this software display the following acknowledgement:
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* ``This product includes software developed by the University of California,
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* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
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* the University nor the names of its contributors may be used to endorse
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* or promote products derived from this software without specific prior
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* written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#ifndef lint
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char copyright[] =
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"@(#) Copyright (c) 1990, 1991, 1992, 1993, 1996\n\
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The Regents of the University of California. All rights reserved.\n";
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#endif /* not lint */
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#ifndef lint
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static const char rcsid[] =
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"$FreeBSD$";
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#endif
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/*
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* rarpd - Reverse ARP Daemon
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*
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* Usage: rarpd -a [ -fsv ] [ hostname ]
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* rarpd [ -fsv ] interface [ hostname ]
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*
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* 'hostname' is optional solely for backwards compatibility with Sun's rarpd.
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* Currently, the argument is ignored.
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*/
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#include <sys/param.h>
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#include <sys/file.h>
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#include <sys/ioctl.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include <net/bpf.h>
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#include <net/if.h>
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#include <net/if_var.h>
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#include <net/if_types.h>
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#include <net/if_dl.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/if_ether.h>
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#include <arpa/inet.h>
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#include <errno.h>
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#include <netdb.h>
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#include <stdio.h>
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#include <string.h>
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#include <syslog.h>
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#include <stdlib.h>
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#include <unistd.h>
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#if defined(SUNOS4) || defined(__FreeBSD__) /* XXX */
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#define HAVE_DIRENT_H
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#endif
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#ifdef HAVE_DIRENT_H
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#include <dirent.h>
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#else
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#include <sys/dir.h>
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#endif
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/* Cast a struct sockaddr to a structaddr_in */
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#define SATOSIN(sa) ((struct sockaddr_in *)(sa))
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#ifndef TFTP_DIR
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#define TFTP_DIR "/tftpboot"
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#endif
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#if BSD >= 199200
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#define ARPSECS (20 * 60) /* as per code in netinet/if_ether.c */
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#define REVARP_REQUEST ARPOP_REVREQUEST
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#define REVARP_REPLY ARPOP_REVREPLY
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#endif
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#ifndef ETHERTYPE_REVARP
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#define ETHERTYPE_REVARP 0x8035
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#define REVARP_REQUEST 3
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#define REVARP_REPLY 4
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#endif
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/*
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* Map field names in ether_arp struct. What a pain in the neck.
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*/
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#ifdef SUNOS3
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#undef arp_sha
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#undef arp_spa
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#undef arp_tha
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#undef arp_tpa
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#define arp_sha arp_xsha
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#define arp_spa arp_xspa
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#define arp_tha arp_xtha
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#define arp_tpa arp_xtpa
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#endif
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#ifndef __GNUC__
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#define inline
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#endif
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/*
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* The structure for each interface.
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*/
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struct if_info {
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struct if_info *ii_next;
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int ii_fd; /* BPF file descriptor */
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u_long ii_ipaddr; /* IP address of this interface */
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u_long ii_netmask; /* subnet or net mask */
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u_char ii_eaddr[6]; /* Ethernet address of this interface */
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char ii_ifname[sizeof(((struct ifreq *)0)->ifr_name) + 1];
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};
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/*
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* The list of all interfaces that are being listened to. rarp_loop()
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* "selects" on the descriptors in this list.
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*/
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struct if_info *iflist;
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int verbose; /* verbose messages */
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int s; /* inet datagram socket */
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char *tftp_dir = TFTP_DIR; /* tftp directory */
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#ifndef __P
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#define __P(protos) ()
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#endif
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#if BSD < 199200
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extern char *malloc();
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extern void exit();
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#endif
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extern int ether_ntohost();
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void init __P((char *));
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void init_one __P((struct ifreq *, char *));
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char *intoa __P((u_long));
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u_long ipaddrtonetmask __P((u_long));
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char *eatoa __P((u_char *));
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int rarp_bootable __P((u_long));
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void rarp_loop __P((void));
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int rarp_open __P((char *));
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void rarp_process __P((struct if_info *, u_char *, u_int));
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void rarp_reply __P((struct if_info *, struct ether_header *, u_long, u_int));
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void update_arptab __P((u_char *, u_long));
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void usage __P((void));
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static u_char zero[6];
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int sflag = 0; /* ignore /tftpboot */
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void
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main(argc, argv)
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int argc;
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char **argv;
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{
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int op;
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char *ifname, *hostname, *name;
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int aflag = 0; /* listen on "all" interfaces */
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int fflag = 0; /* don't fork */
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if ((name = strrchr(argv[0], '/')) != NULL)
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++name;
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else
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name = argv[0];
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if (*name == '-')
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++name;
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/*
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* All error reporting is done through syslogs.
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*/
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openlog(name, LOG_PID | LOG_CONS, LOG_DAEMON);
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opterr = 0;
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while ((op = getopt(argc, argv, "afsv")) != EOF) {
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switch (op) {
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case 'a':
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++aflag;
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break;
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case 'f':
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++fflag;
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break;
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case 's':
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++sflag;
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break;
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case 'v':
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++verbose;
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break;
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default:
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usage();
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/* NOTREACHED */
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}
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}
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ifname = argv[optind++];
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hostname = ifname ? argv[optind] : NULL;
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if ((aflag && ifname) || (!aflag && ifname == NULL))
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usage();
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if (aflag)
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init(NULL);
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else
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init(ifname);
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if (!fflag) {
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if (daemon(0,0)) {
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syslog(LOG_ERR, "cannot fork");
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exit(1);
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}
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}
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rarp_loop();
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}
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/*
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* Add to the interface list.
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*/
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void
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init_one(ifrp, target)
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register struct ifreq *ifrp;
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register char *target;
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{
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register struct if_info *ii;
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register struct sockaddr_dl *ll;
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int family;
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struct ifreq ifr;
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family = ifrp->ifr_addr.sa_family;
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switch (family) {
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case AF_INET:
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#if BSD >= 199100
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case AF_LINK:
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#endif
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(void)strncpy(ifr.ifr_name, ifrp->ifr_name,
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sizeof(ifrp->ifr_name));
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if (ioctl(s, SIOCGIFFLAGS, (char *)&ifr) < 0) {
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syslog(LOG_ERR,
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"SIOCGIFFLAGS: %.*s: %m",
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sizeof(ifrp->ifr_name), ifrp->ifr_name);
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exit(1);
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}
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if ((ifr.ifr_flags & IFF_UP) == 0 ||
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(ifr.ifr_flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) != 0)
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return;
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break;
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default:
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return;
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}
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/* Don't bother going any further if not the target interface */
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if (target != NULL &&
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strncmp(ifrp->ifr_name, target, sizeof(ifrp->ifr_name)) != 0)
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return;
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/* Look for interface in list */
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for (ii = iflist; ii != NULL; ii = ii->ii_next)
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if (strncmp(ifrp->ifr_name, ii->ii_ifname,
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sizeof(ifrp->ifr_name)) == 0)
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break;
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/* Allocate a new one if not found */
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if (ii == NULL) {
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ii = (struct if_info *)malloc(sizeof(*ii));
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if (ii == NULL) {
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syslog(LOG_ERR, "malloc: %m");
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exit(1);
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}
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bzero(ii, sizeof(*ii));
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ii->ii_fd = -1;
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(void)strncpy(ii->ii_ifname, ifrp->ifr_name,
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sizeof(ifrp->ifr_name));
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ii->ii_ifname[sizeof(ii->ii_ifname) - 1] = '\0';
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ii->ii_next = iflist;
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iflist = ii;
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}
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switch (family) {
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case AF_INET:
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if (ioctl(s, SIOCGIFADDR, (char *)&ifr) < 0) {
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syslog(LOG_ERR, "ipaddr SIOCGIFADDR: %s: %m",
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ii->ii_ifname);
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exit(1);
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}
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ii->ii_ipaddr = SATOSIN(&ifr.ifr_addr)->sin_addr.s_addr;
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if (ioctl(s, SIOCGIFNETMASK, (char *)&ifr) < 0) {
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syslog(LOG_ERR, "SIOCGIFNETMASK: %m");
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exit(1);
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}
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ii->ii_netmask = SATOSIN(&ifr.ifr_addr)->sin_addr.s_addr;
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if (ii->ii_netmask == 0)
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ii->ii_netmask = ipaddrtonetmask(ii->ii_ipaddr);
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if (ii->ii_fd < 0) {
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ii->ii_fd = rarp_open(ii->ii_ifname);
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#if BSD < 199100
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/* Use BPF descriptor to get ethernet address. */
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if (ioctl(ii->ii_fd, SIOCGIFADDR, (char *)&ifr) < 0) {
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syslog(LOG_ERR, "eaddr SIOCGIFADDR: %s: %m",
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ii->ii_ifname);
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exit(1);
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}
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bcopy(&ifr.ifr_addr.sa_data[0], ii->ii_eaddr, 6);
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#endif
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}
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break;
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#if BSD >= 199100
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case AF_LINK:
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ll = (struct sockaddr_dl *)&ifrp->ifr_addr;
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if (ll->sdl_type == IFT_ETHER)
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bcopy(LLADDR(ll), ii->ii_eaddr, 6);
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break;
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#endif
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}
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}
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/*
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* Initialize all "candidate" interfaces that are in the system
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* configuration list. A "candidate" is up, not loopback and not
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* point to point.
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*/
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void
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init(target)
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char *target;
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{
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register int n;
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register struct ifreq *ifrp, *ifend;
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register struct if_info *ii, *nii, *lii;
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struct ifconf ifc;
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struct ifreq ibuf[16];
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if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
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syslog(LOG_ERR, "socket: %m");
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exit(1);
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}
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ifc.ifc_len = sizeof ibuf;
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ifc.ifc_buf = (caddr_t)ibuf;
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if (ioctl(s, SIOCGIFCONF, (char *)&ifc) < 0 ||
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(u_int)ifc.ifc_len < sizeof(struct ifreq)) {
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syslog(LOG_ERR, "SIOCGIFCONF: %m");
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exit(1);
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}
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ifrp = ibuf;
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ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len);
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while (ifrp < ifend) {
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init_one(ifrp, target);
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#if BSD >= 199100
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n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name);
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if (n < sizeof(*ifrp))
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n = sizeof(*ifrp);
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ifrp = (struct ifreq *)((char *)ifrp + n);
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#else
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++ifrp;
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#endif
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}
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/* Throw away incomplete interfaces */
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lii = NULL;
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for (ii = iflist; ii != NULL; ii = nii) {
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nii = ii->ii_next;
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if (ii->ii_ipaddr == 0 ||
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bcmp(ii->ii_eaddr, zero, 6) == 0) {
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if (lii == NULL)
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iflist = nii;
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else
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lii->ii_next = nii;
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if (ii->ii_fd >= 0)
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close(ii->ii_fd);
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free(ii);
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continue;
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}
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lii = ii;
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}
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/* Verbose stuff */
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if (verbose)
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for (ii = iflist; ii != NULL; ii = ii->ii_next)
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syslog(LOG_DEBUG, "%s %s 0x%08x %s",
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ii->ii_ifname, intoa(ntohl(ii->ii_ipaddr)),
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ntohl(ii->ii_netmask), eatoa(ii->ii_eaddr));
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}
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void
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usage()
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{
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(void)fprintf(stderr, "usage: rarpd [ -afnv ] [ interface ]\n");
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exit(1);
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}
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static int
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bpf_open()
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{
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int fd;
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int n = 0;
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char device[sizeof "/dev/bpf000"];
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|
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/*
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* Go through all the minors and find one that isn't in use.
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*/
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do {
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(void)sprintf(device, "/dev/bpf%d", n++);
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fd = open(device, O_RDWR);
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} while (fd < 0 && errno == EBUSY);
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if (fd < 0) {
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syslog(LOG_ERR, "%s: %m", device);
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exit(1);
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}
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return fd;
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}
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/*
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* Open a BPF file and attach it to the interface named 'device'.
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* Set immediate mode, and set a filter that accepts only RARP requests.
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*/
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int
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rarp_open(device)
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char *device;
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{
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int fd;
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struct ifreq ifr;
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u_int dlt;
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int immediate;
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|
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static struct bpf_insn insns[] = {
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BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 12),
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BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, ETHERTYPE_REVARP, 0, 3),
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BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 20),
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BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, REVARP_REQUEST, 0, 1),
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BPF_STMT(BPF_RET|BPF_K, sizeof(struct ether_arp) +
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sizeof(struct ether_header)),
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BPF_STMT(BPF_RET|BPF_K, 0),
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};
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static struct bpf_program filter = {
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sizeof insns / sizeof(insns[0]),
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insns
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};
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|
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fd = bpf_open();
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/*
|
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* Set immediate mode so packets are processed as they arrive.
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*/
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immediate = 1;
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if (ioctl(fd, BIOCIMMEDIATE, &immediate) < 0) {
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syslog(LOG_ERR, "BIOCIMMEDIATE: %m");
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exit(1);
|
|
}
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(void)strncpy(ifr.ifr_name, device, sizeof ifr.ifr_name);
|
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if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) {
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syslog(LOG_ERR, "BIOCSETIF: %m");
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exit(1);
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|
}
|
|
/*
|
|
* Check that the data link layer is an Ethernet; this code won't
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* work with anything else.
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|
*/
|
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if (ioctl(fd, BIOCGDLT, (caddr_t)&dlt) < 0) {
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syslog(LOG_ERR, "BIOCGDLT: %m");
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exit(1);
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|
}
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if (dlt != DLT_EN10MB) {
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syslog(LOG_ERR, "%s is not an ethernet", device);
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exit(1);
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|
}
|
|
/*
|
|
* Set filter program.
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|
*/
|
|
if (ioctl(fd, BIOCSETF, (caddr_t)&filter) < 0) {
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|
syslog(LOG_ERR, "BIOCSETF: %m");
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exit(1);
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}
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|
return fd;
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}
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|
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/*
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|
* Perform various sanity checks on the RARP request packet. Return
|
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* false on failure and log the reason.
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|
*/
|
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static int
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rarp_check(p, len)
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u_char *p;
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u_int len;
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{
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struct ether_header *ep = (struct ether_header *)p;
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struct ether_arp *ap = (struct ether_arp *)(p + sizeof(*ep));
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|
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if (len < sizeof(*ep) + sizeof(*ap)) {
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syslog(LOG_ERR, "truncated request, got %d, expected %d",
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len, sizeof(*ep) + sizeof(*ap));
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return 0;
|
|
}
|
|
/*
|
|
* XXX This test might be better off broken out...
|
|
*/
|
|
if (ntohs(ep->ether_type) != ETHERTYPE_REVARP ||
|
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ntohs(ap->arp_hrd) != ARPHRD_ETHER ||
|
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ntohs(ap->arp_op) != REVARP_REQUEST ||
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ntohs(ap->arp_pro) != ETHERTYPE_IP ||
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ap->arp_hln != 6 || ap->arp_pln != 4) {
|
|
syslog(LOG_DEBUG, "request fails sanity check");
|
|
return 0;
|
|
}
|
|
if (bcmp((char *)&ep->ether_shost, (char *)&ap->arp_sha, 6) != 0) {
|
|
syslog(LOG_DEBUG, "ether/arp sender address mismatch");
|
|
return 0;
|
|
}
|
|
if (bcmp((char *)&ap->arp_sha, (char *)&ap->arp_tha, 6) != 0) {
|
|
syslog(LOG_DEBUG, "ether/arp target address mismatch");
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
#ifndef FD_SETSIZE
|
|
#define FD_SET(n, fdp) ((fdp)->fds_bits[0] |= (1 << (n)))
|
|
#define FD_ISSET(n, fdp) ((fdp)->fds_bits[0] & (1 << (n)))
|
|
#define FD_ZERO(fdp) ((fdp)->fds_bits[0] = 0)
|
|
#endif
|
|
|
|
/*
|
|
* Loop indefinitely listening for RARP requests on the
|
|
* interfaces in 'iflist'.
|
|
*/
|
|
void
|
|
rarp_loop()
|
|
{
|
|
u_char *buf, *bp, *ep;
|
|
int cc, fd;
|
|
fd_set fds, listeners;
|
|
int bufsize, maxfd = 0;
|
|
struct if_info *ii;
|
|
|
|
if (iflist == NULL) {
|
|
syslog(LOG_ERR, "no interfaces");
|
|
exit(1);
|
|
}
|
|
if (ioctl(iflist->ii_fd, BIOCGBLEN, (caddr_t)&bufsize) < 0) {
|
|
syslog(LOG_ERR, "BIOCGBLEN: %m");
|
|
exit(1);
|
|
}
|
|
buf = (u_char *)malloc((unsigned)bufsize);
|
|
if (buf == NULL) {
|
|
syslog(LOG_ERR, "malloc: %m");
|
|
exit(1);
|
|
}
|
|
|
|
while (1) {
|
|
/*
|
|
* Find the highest numbered file descriptor for select().
|
|
* Initialize the set of descriptors to listen to.
|
|
*/
|
|
FD_ZERO(&fds);
|
|
for (ii = iflist; ii != NULL; ii = ii->ii_next) {
|
|
FD_SET(ii->ii_fd, &fds);
|
|
if (ii->ii_fd > maxfd)
|
|
maxfd = ii->ii_fd;
|
|
}
|
|
listeners = fds;
|
|
if (select(maxfd + 1, &listeners, NULL, NULL, NULL) < 0) {
|
|
/* Don't choke when we get ptraced */
|
|
if (errno == EINTR)
|
|
continue;
|
|
syslog(LOG_ERR, "select: %m");
|
|
exit(1);
|
|
}
|
|
for (ii = iflist; ii != NULL; ii = ii->ii_next) {
|
|
fd = ii->ii_fd;
|
|
if (!FD_ISSET(fd, &listeners))
|
|
continue;
|
|
again:
|
|
cc = read(fd, (char *)buf, bufsize);
|
|
/* Don't choke when we get ptraced */
|
|
if (cc < 0 && errno == EINTR)
|
|
goto again;
|
|
#if defined(SUNOS3) || defined(SUNOS4)
|
|
/*
|
|
* Due to a SunOS bug, after 2^31 bytes, the
|
|
* file offset overflows and read fails with
|
|
* EINVAL. The lseek() to 0 will fix things.
|
|
*/
|
|
if (cc < 0) {
|
|
if (errno == EINVAL &&
|
|
(long)(tell(fd) + bufsize) < 0) {
|
|
(void)lseek(fd, 0, 0);
|
|
goto again;
|
|
}
|
|
syslog(LOG_ERR, "read: %m");
|
|
exit(1);
|
|
}
|
|
#endif
|
|
|
|
/* Loop through the packet(s) */
|
|
#define bhp ((struct bpf_hdr *)bp)
|
|
bp = buf;
|
|
ep = bp + cc;
|
|
while (bp < ep) {
|
|
register u_int caplen, hdrlen;
|
|
|
|
caplen = bhp->bh_caplen;
|
|
hdrlen = bhp->bh_hdrlen;
|
|
if (rarp_check(bp + hdrlen, caplen))
|
|
rarp_process(ii, bp + hdrlen, caplen);
|
|
bp += BPF_WORDALIGN(hdrlen + caplen);
|
|
}
|
|
}
|
|
}
|
|
#undef bhp
|
|
}
|
|
|
|
/*
|
|
* True if this server can boot the host whose IP address is 'addr'.
|
|
* This check is made by looking in the tftp directory for the
|
|
* configuration file.
|
|
*/
|
|
int
|
|
rarp_bootable(addr)
|
|
u_long addr;
|
|
{
|
|
#ifdef HAVE_DIRENT_H
|
|
register struct dirent *dent;
|
|
#else
|
|
register struct direct *dent;
|
|
#endif
|
|
register DIR *d;
|
|
char ipname[9];
|
|
static DIR *dd = NULL;
|
|
|
|
(void)sprintf(ipname, "%08X", (unsigned int )ntohl(addr));
|
|
|
|
/*
|
|
* If directory is already open, rewind it. Otherwise, open it.
|
|
*/
|
|
if ((d = dd) != NULL)
|
|
rewinddir(d);
|
|
else {
|
|
if (chdir(tftp_dir) == -1) {
|
|
syslog(LOG_ERR, "chdir: %s: %m", tftp_dir);
|
|
exit(1);
|
|
}
|
|
d = opendir(".");
|
|
if (d == NULL) {
|
|
syslog(LOG_ERR, "opendir: %m");
|
|
exit(1);
|
|
}
|
|
dd = d;
|
|
}
|
|
while ((dent = readdir(d)) != NULL)
|
|
if (strncmp(dent->d_name, ipname, 8) == 0)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Given a list of IP addresses, 'alist', return the first address that
|
|
* is on network 'net'; 'netmask' is a mask indicating the network portion
|
|
* of the address.
|
|
*/
|
|
u_long
|
|
choose_ipaddr(alist, net, netmask)
|
|
u_long **alist;
|
|
u_long net;
|
|
u_long netmask;
|
|
{
|
|
for (; *alist; ++alist)
|
|
if ((**alist & netmask) == net)
|
|
return **alist;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Answer the RARP request in 'pkt', on the interface 'ii'. 'pkt' has
|
|
* already been checked for validity. The reply is overlaid on the request.
|
|
*/
|
|
void
|
|
rarp_process(ii, pkt, len)
|
|
struct if_info *ii;
|
|
u_char *pkt;
|
|
u_int len;
|
|
{
|
|
struct ether_header *ep;
|
|
struct hostent *hp;
|
|
u_long target_ipaddr;
|
|
char ename[256];
|
|
|
|
ep = (struct ether_header *)pkt;
|
|
/* should this be arp_tha? */
|
|
if (ether_ntohost(ename, &ep->ether_shost) != 0) {
|
|
syslog(LOG_ERR, "cannot map %s to name",
|
|
eatoa(ep->ether_shost));
|
|
return;
|
|
}
|
|
|
|
if ((hp = gethostbyname(ename)) == NULL) {
|
|
syslog(LOG_ERR, "cannot map %s to IP address", ename);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Choose correct address from list.
|
|
*/
|
|
if (hp->h_addrtype != AF_INET) {
|
|
syslog(LOG_ERR, "cannot handle non IP addresses for %s",
|
|
ename);
|
|
return;
|
|
}
|
|
target_ipaddr = choose_ipaddr((u_long **)hp->h_addr_list,
|
|
ii->ii_ipaddr & ii->ii_netmask,
|
|
ii->ii_netmask);
|
|
if (target_ipaddr == 0) {
|
|
syslog(LOG_ERR, "cannot find %s on net %s",
|
|
ename, intoa(ntohl(ii->ii_ipaddr & ii->ii_netmask)));
|
|
return;
|
|
}
|
|
if (sflag || rarp_bootable(target_ipaddr))
|
|
rarp_reply(ii, ep, target_ipaddr, len);
|
|
else if (verbose > 1)
|
|
syslog(LOG_INFO, "%s %s at %s DENIED (not bootable)",
|
|
ii->ii_ifname,
|
|
eatoa(ep->ether_shost),
|
|
intoa(ntohl(target_ipaddr)));
|
|
}
|
|
|
|
/*
|
|
* Poke the kernel arp tables with the ethernet/ip address combinataion
|
|
* given. When processing a reply, we must do this so that the booting
|
|
* host (i.e. the guy running rarpd), won't try to ARP for the hardware
|
|
* address of the guy being booted (he cannot answer the ARP).
|
|
*/
|
|
#if BSD >= 199200
|
|
static struct sockaddr_inarp sin_inarp = {
|
|
sizeof(struct sockaddr_inarp), AF_INET
|
|
};
|
|
static struct sockaddr_dl sin_dl = {
|
|
sizeof(struct sockaddr_dl), AF_LINK, 0, IFT_ETHER, 0, 6
|
|
};
|
|
static struct {
|
|
struct rt_msghdr rthdr;
|
|
char rtspace[512];
|
|
} rtmsg;
|
|
|
|
void
|
|
update_arptab(ep, ipaddr)
|
|
u_char *ep;
|
|
u_long ipaddr;
|
|
{
|
|
register int cc;
|
|
register struct sockaddr_inarp *ar, *ar2;
|
|
register struct sockaddr_dl *ll, *ll2;
|
|
register struct rt_msghdr *rt;
|
|
register int xtype, xindex;
|
|
static pid_t pid;
|
|
static int r, seq;
|
|
static init = 0;
|
|
|
|
if (!init) {
|
|
r = socket(PF_ROUTE, SOCK_RAW, 0);
|
|
if (r < 0) {
|
|
syslog(LOG_ERR, "raw route socket: %m");
|
|
exit(1);
|
|
}
|
|
pid = getpid();
|
|
++init;
|
|
}
|
|
|
|
ar = &sin_inarp;
|
|
ar->sin_addr.s_addr = ipaddr;
|
|
ll = &sin_dl;
|
|
bcopy(ep, LLADDR(ll), 6);
|
|
|
|
/* Get the type and interface index */
|
|
rt = &rtmsg.rthdr;
|
|
bzero(rt, sizeof(rtmsg));
|
|
rt->rtm_version = RTM_VERSION;
|
|
rt->rtm_addrs = RTA_DST;
|
|
rt->rtm_type = RTM_GET;
|
|
rt->rtm_seq = ++seq;
|
|
ar2 = (struct sockaddr_inarp *)rtmsg.rtspace;
|
|
bcopy(ar, ar2, sizeof(*ar));
|
|
rt->rtm_msglen = sizeof(*rt) + sizeof(*ar);
|
|
errno = 0;
|
|
if (write(r, rt, rt->rtm_msglen) < 0 && errno != ESRCH) {
|
|
syslog(LOG_ERR, "rtmsg get write: %m");
|
|
return;
|
|
}
|
|
do {
|
|
cc = read(r, rt, sizeof(rtmsg));
|
|
} while (cc > 0 && (rt->rtm_seq != seq || rt->rtm_pid != pid));
|
|
if (cc < 0) {
|
|
syslog(LOG_ERR, "rtmsg get read: %m");
|
|
return;
|
|
}
|
|
ll2 = (struct sockaddr_dl *)((u_char *)ar2 + ar2->sin_len);
|
|
if (ll2->sdl_family != AF_LINK) {
|
|
/*
|
|
* XXX I think this means the ip address is not on a
|
|
* directly connected network (the family is AF_INET in
|
|
* this case).
|
|
*/
|
|
syslog(LOG_ERR, "bogus link family (%d) wrong net for %08X?\n",
|
|
ll2->sdl_family, ipaddr);
|
|
return;
|
|
}
|
|
xtype = ll2->sdl_type;
|
|
xindex = ll2->sdl_index;
|
|
|
|
/* Set the new arp entry */
|
|
bzero(rt, sizeof(rtmsg));
|
|
rt->rtm_version = RTM_VERSION;
|
|
rt->rtm_addrs = RTA_DST | RTA_GATEWAY;
|
|
rt->rtm_inits = RTV_EXPIRE;
|
|
rt->rtm_rmx.rmx_expire = time(0) + ARPSECS;
|
|
rt->rtm_flags = RTF_HOST | RTF_STATIC;
|
|
rt->rtm_type = RTM_ADD;
|
|
rt->rtm_seq = ++seq;
|
|
|
|
bcopy(ar, ar2, sizeof(*ar));
|
|
|
|
ll2 = (struct sockaddr_dl *)((u_char *)ar2 + sizeof(*ar2));
|
|
bcopy(ll, ll2, sizeof(*ll));
|
|
ll2->sdl_type = xtype;
|
|
ll2->sdl_index = xindex;
|
|
|
|
rt->rtm_msglen = sizeof(*rt) + sizeof(*ar2) + sizeof(*ll2);
|
|
errno = 0;
|
|
if (write(r, rt, rt->rtm_msglen) < 0 && errno != EEXIST) {
|
|
syslog(LOG_ERR, "rtmsg add write: %m");
|
|
return;
|
|
}
|
|
do {
|
|
cc = read(r, rt, sizeof(rtmsg));
|
|
} while (cc > 0 && (rt->rtm_seq != seq || rt->rtm_pid != pid));
|
|
if (cc < 0) {
|
|
syslog(LOG_ERR, "rtmsg add read: %m");
|
|
return;
|
|
}
|
|
}
|
|
#else
|
|
void
|
|
update_arptab(ep, ipaddr)
|
|
u_char *ep;
|
|
u_long ipaddr;
|
|
{
|
|
struct arpreq request;
|
|
struct sockaddr_in *sin;
|
|
|
|
request.arp_flags = 0;
|
|
sin = (struct sockaddr_in *)&request.arp_pa;
|
|
sin->sin_family = AF_INET;
|
|
sin->sin_addr.s_addr = ipaddr;
|
|
request.arp_ha.sa_family = AF_UNSPEC;
|
|
bcopy((char *)ep, (char *)request.arp_ha.sa_data, 6);
|
|
|
|
if (ioctl(s, SIOCSARP, (caddr_t)&request) < 0)
|
|
syslog(LOG_ERR, "SIOCSARP: %m");
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Build a reverse ARP packet and sent it out on the interface.
|
|
* 'ep' points to a valid REVARP_REQUEST. The REVARP_REPLY is built
|
|
* on top of the request, then written to the network.
|
|
*
|
|
* RFC 903 defines the ether_arp fields as follows. The following comments
|
|
* are taken (more or less) straight from this document.
|
|
*
|
|
* REVARP_REQUEST
|
|
*
|
|
* arp_sha is the hardware address of the sender of the packet.
|
|
* arp_spa is undefined.
|
|
* arp_tha is the 'target' hardware address.
|
|
* In the case where the sender wishes to determine his own
|
|
* protocol address, this, like arp_sha, will be the hardware
|
|
* address of the sender.
|
|
* arp_tpa is undefined.
|
|
*
|
|
* REVARP_REPLY
|
|
*
|
|
* arp_sha is the hardware address of the responder (the sender of the
|
|
* reply packet).
|
|
* arp_spa is the protocol address of the responder (see the note below).
|
|
* arp_tha is the hardware address of the target, and should be the same as
|
|
* that which was given in the request.
|
|
* arp_tpa is the protocol address of the target, that is, the desired address.
|
|
*
|
|
* Note that the requirement that arp_spa be filled in with the responder's
|
|
* protocol is purely for convenience. For instance, if a system were to use
|
|
* both ARP and RARP, then the inclusion of the valid protocol-hardware
|
|
* address pair (arp_spa, arp_sha) may eliminate the need for a subsequent
|
|
* ARP request.
|
|
*/
|
|
void
|
|
rarp_reply(ii, ep, ipaddr, len)
|
|
struct if_info *ii;
|
|
struct ether_header *ep;
|
|
u_long ipaddr;
|
|
u_int len;
|
|
{
|
|
int n;
|
|
struct ether_arp *ap = (struct ether_arp *)(ep + 1);
|
|
|
|
update_arptab((u_char *)&ap->arp_sha, ipaddr);
|
|
|
|
/*
|
|
* Build the rarp reply by modifying the rarp request in place.
|
|
*/
|
|
ap->arp_op = htons(REVARP_REPLY);
|
|
|
|
#ifdef BROKEN_BPF
|
|
ep->ether_type = ETHERTYPE_REVARP;
|
|
#endif
|
|
bcopy((char *)&ap->arp_sha, (char *)&ep->ether_dhost, 6);
|
|
bcopy((char *)ii->ii_eaddr, (char *)&ep->ether_shost, 6);
|
|
bcopy((char *)ii->ii_eaddr, (char *)&ap->arp_sha, 6);
|
|
|
|
bcopy((char *)&ipaddr, (char *)ap->arp_tpa, 4);
|
|
/* Target hardware is unchanged. */
|
|
bcopy((char *)&ii->ii_ipaddr, (char *)ap->arp_spa, 4);
|
|
|
|
/* Zero possible garbage after packet. */
|
|
bzero((char *)ep + (sizeof(*ep) + sizeof(*ap)),
|
|
len - (sizeof(*ep) + sizeof(*ap)));
|
|
n = write(ii->ii_fd, (char *)ep, len);
|
|
if (n != len)
|
|
syslog(LOG_ERR, "write: only %d of %d bytes written", n, len);
|
|
if (verbose)
|
|
syslog(LOG_INFO, "%s %s at %s REPLIED", ii->ii_ifname,
|
|
eatoa(ap->arp_tha),
|
|
intoa(ntohl(ipaddr)));
|
|
}
|
|
|
|
/*
|
|
* Get the netmask of an IP address. This routine is used if
|
|
* SIOCGIFNETMASK doesn't work.
|
|
*/
|
|
u_long
|
|
ipaddrtonetmask(addr)
|
|
u_long addr;
|
|
{
|
|
addr = ntohl(addr);
|
|
if (IN_CLASSA(addr))
|
|
return htonl(IN_CLASSA_NET);
|
|
if (IN_CLASSB(addr))
|
|
return htonl(IN_CLASSB_NET);
|
|
if (IN_CLASSC(addr))
|
|
return htonl(IN_CLASSC_NET);
|
|
syslog(LOG_DEBUG, "unknown IP address class: %08X", addr);
|
|
return htonl(0xffffffff);
|
|
}
|
|
|
|
/*
|
|
* A faster replacement for inet_ntoa().
|
|
*/
|
|
char *
|
|
intoa(addr)
|
|
u_long addr;
|
|
{
|
|
register char *cp;
|
|
register u_int byte;
|
|
register int n;
|
|
static char buf[sizeof(".xxx.xxx.xxx.xxx")];
|
|
|
|
cp = &buf[sizeof buf];
|
|
*--cp = '\0';
|
|
|
|
n = 4;
|
|
do {
|
|
byte = addr & 0xff;
|
|
*--cp = byte % 10 + '0';
|
|
byte /= 10;
|
|
if (byte > 0) {
|
|
*--cp = byte % 10 + '0';
|
|
byte /= 10;
|
|
if (byte > 0)
|
|
*--cp = byte + '0';
|
|
}
|
|
*--cp = '.';
|
|
addr >>= 8;
|
|
} while (--n > 0);
|
|
|
|
return cp + 1;
|
|
}
|
|
|
|
char *
|
|
eatoa(ea)
|
|
register u_char *ea;
|
|
{
|
|
static char buf[sizeof("xx:xx:xx:xx:xx:xx")];
|
|
|
|
(void)sprintf(buf, "%x:%x:%x:%x:%x:%x",
|
|
ea[0], ea[1], ea[2], ea[3], ea[4], ea[5]);
|
|
return (buf);
|
|
}
|