diff options
Diffstat (limited to 'network_cmds/rarpd.tproj/rarpd.c')
| -rw-r--r-- | network_cmds/rarpd.tproj/rarpd.c | 830 |
1 files changed, 830 insertions, 0 deletions
diff --git a/network_cmds/rarpd.tproj/rarpd.c b/network_cmds/rarpd.tproj/rarpd.c new file mode 100644 index 0000000..1a3ae51 --- /dev/null +++ b/network_cmds/rarpd.tproj/rarpd.c @@ -0,0 +1,830 @@ +/* + * Copyright (c) 1999-2009 Apple Computer, Inc. All rights reserved. + * + * @APPLE_LICENSE_HEADER_START@ + * + * "Portions Copyright (c) 1999 Apple Computer, Inc. All Rights + * Reserved. This file contains Original Code and/or Modifications of + * Original Code as defined in and that are subject to the Apple Public + * Source License Version 1.0 (the 'License'). You may not use this file + * except in compliance with the License. Please obtain a copy of the + * License at http://www.apple.com/publicsource and read it before using + * this file. + * + * The Original Code and all software distributed under the License are + * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER + * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, + * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the + * License for the specific language governing rights and limitations + * under the License." + * + * @APPLE_LICENSE_HEADER_END@ + */ +/* + * Copyright (c) 1990 The Regents of the University of California. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that: (1) source code distributions + * retain the above copyright notice and this paragraph in its entirety, (2) + * distributions including binary code include the above copyright notice and + * this paragraph in its entirety in the documentation or other materials + * provided with the distribution, and (3) all advertising materials mentioning + * features or use of this software display the following acknowledgement: + * ``This product includes software developed by the University of California, + * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of + * the University nor the names of its contributors may be used to endorse + * or promote products derived from this software without specific prior + * written permission. + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. + */ + +#include <sys/cdefs.h> + +#ifndef lint +__unused char copyright[] = +"@(#) Copyright (c) 1990 The Regents of the University of California.\n\ + All rights reserved.\n"; +#endif /* not lint */ + +/* + * rarpd - Reverse ARP Daemon + * + * Usage: rarpd -a [ -d -f ] + * rarpd [ -d -f ] interface + */ + +#include <stdio.h> +#include <stdlib.h> +#include <syslog.h> +#include <string.h> +#include <strings.h> +#include <sys/types.h> +#include <unistd.h> +#include <sys/time.h> +#include <net/bpf.h> +#include <sys/socket.h> +#include <sys/ioctl.h> +#include <net/if.h> +#include <net/if_dl.h> +#include <net/if_types.h> +#include <netinet/in.h> +#include <netinet/if_ether.h> +#include <sys/errno.h> +#include <sys/file.h> +#include <netdb.h> +#include <arpa/inet.h> +#include <dirent.h> + +#define FATAL 1 /* fatal error occurred */ +#define NONFATAL 0 /* non fatal error occurred */ + +/* + * The structure for each interface. + */ +struct if_info { + int ii_fd; /* BPF file descriptor */ + u_char ii_eaddr[6]; /* Ethernet address of this interface */ + in_addr_t ii_ipaddr; /* IP address of this interface */ + in_addr_t ii_netmask; /* subnet or net mask */ + struct if_info *ii_next; +}; +/* + * The list of all interfaces that are being listened to. rarp_loop() + * "selects" on the descriptors in this list. + */ +struct if_info *iflist; + +int rarp_open __P((char *)); +int rarp_bootable __P((in_addr_t)); +void init_one __P((char *)); +void init_all __P((void)); +void rarp_loop __P((void)); +void lookup_eaddr __P((char *, u_char *)); +void lookup_ipaddr __P((char *, in_addr_t *, in_addr_t *)); +void usage __P((void)); +void rarp_process __P((struct if_info *, u_char *)); +void rarp_reply __P((struct if_info *, struct ether_header *, in_addr_t)); +void update_arptab __P((u_char *, in_addr_t)); +void err __P((int, const char *,...)); +void debug __P((const char *,...)); +in_addr_t ipaddrtonetmask __P((in_addr_t)); + +int aflag = 0; /* listen on "all" interfaces */ +int dflag = 0; /* print debugging messages */ +int fflag = 0; /* don't fork */ + +int +main(argc, argv) + int argc; + char **argv; +{ + int op, pid, devnull, f; + char *ifname, *hostname, *name; + + extern int optind, opterr; + + if ((name = strrchr(argv[0], '/')) != NULL) + ++name; + else + name = argv[0]; + if (*name == '-') + ++name; + + /* All error reporting is done through syslogs. */ + openlog(name, LOG_PID | LOG_CONS, LOG_DAEMON); + + opterr = 0; + while ((op = getopt(argc, argv, "adf")) != EOF) { + switch (op) { + case 'a': + ++aflag; + break; + + case 'd': + ++dflag; + break; + + case 'f': + ++fflag; + break; + + default: + usage(); + /* NOTREACHED */ + } + } + ifname = argv[optind++]; + hostname = ifname ? argv[optind] : 0; + if ((aflag && ifname) || (!aflag && ifname == 0)) + usage(); + + if (aflag) + init_all(); + else + init_one(ifname); + + if ((!fflag) && (!dflag)) { + pid = fork(); + if (pid > 0) + /* Parent exits, leaving child in background. */ + exit(0); + else + if (pid == -1) { + err(FATAL, "cannot fork"); + /* NOTREACHED */ + } + /* Fade into the background */ + f = open("/dev/tty", O_RDWR); + if (f >= 0) { + if (ioctl(f, TIOCNOTTY, 0) < 0) { + err(FATAL, "TIOCNOTTY: %s", strerror(errno)); + /* NOTREACHED */ + } + (void) close(f); + } + (void) chdir("/"); + (void) setpgid(0, getpid()); + devnull = open("/dev/null", O_RDWR); + if (devnull >= 0) { + (void) dup2(devnull, 0); + (void) dup2(devnull, 1); + (void) dup2(devnull, 2); + if (devnull > 2) + (void) close(devnull); + } + } + rarp_loop(); + /* NOTREACHED */ + return 0; +} +/* + * Add 'ifname' to the interface list. Lookup its IP address and network + * mask and Ethernet address, and open a BPF file for it. + */ +void +init_one(ifname) + char *ifname; +{ + struct if_info *p; + + p = (struct if_info *)malloc(sizeof(*p)); + if (p == 0) { + err(FATAL, "malloc: %s", strerror(errno)); + /* NOTREACHED */ + } + p->ii_next = iflist; + iflist = p; + + p->ii_fd = rarp_open(ifname); + lookup_eaddr(ifname, p->ii_eaddr); + lookup_ipaddr(ifname, &p->ii_ipaddr, &p->ii_netmask); +} +/* + * Initialize all "candidate" interfaces that are in the system + * configuration list. A "candidate" is up, not loopback and not + * point to point. + */ +void +init_all() +{ + char inbuf[8192]; + struct ifconf ifc; + struct ifreq *ifr; + int fd; + int i, len; + + if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { + err(FATAL, "socket: %s", strerror(errno)); + /* NOTREACHED */ + } + + ifc.ifc_len = sizeof(inbuf); + ifc.ifc_buf = inbuf; + if (ioctl(fd, SIOCGIFCONF, (caddr_t)&ifc) < 0 || + ifc.ifc_len < sizeof(struct ifreq)) { + err(FATAL, "init_all: SIOCGIFCONF: %s", strerror(errno)); + /* NOTREACHED */ + } + ifr = ifc.ifc_req; + for (i = 0; i < ifc.ifc_len; + i += len, ifr = (struct ifreq *)((caddr_t)ifr + len)) { + len = sizeof(ifr->ifr_name) + ifr->ifr_addr.sa_len; + if (ioctl(fd, SIOCGIFFLAGS, (caddr_t)ifr) < 0) { + err(FATAL, "init_all: SIOCGIFFLAGS: %s", + strerror(errno)); + /* NOTREACHED */ + } + if ((ifr->ifr_flags & + (IFF_UP | IFF_LOOPBACK | IFF_POINTOPOINT)) != IFF_UP) + continue; + init_one(ifr->ifr_name); + } + (void) close(fd); +} + +void +usage() +{ + (void) fprintf(stderr, "usage: rarpd -a [ -d -f ]\n"); + (void) fprintf(stderr, " rarpd [ -d -f ] interface\n"); + exit(1); +} + +static int +bpf_open() +{ + int fd; + int n = 0; + char device[sizeof "/dev/bpf000"]; + + /* Go through all the minors and find one that isn't in use. */ + do { + (void) snprintf(device, sizeof(device), "/dev/bpf%d", n++); + fd = open(device, O_RDWR); + } while (fd < 0 && errno == EBUSY); + + if (fd < 0) { + err(FATAL, "%s: %s", device, strerror(errno)); + /* NOTREACHED */ + } + return fd; +} +/* + * Open a BPF file and attach it to the interface named 'device'. + * Set immediate mode, and set a filter that accepts only RARP requests. + */ +int +rarp_open(device) + char *device; +{ + int fd; + struct ifreq ifr; + u_int dlt; + int immediate; + + static struct bpf_insn insns[] = { + BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 12), + BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ETHERTYPE_REVARP, 0, 3), + BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 20), + BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ARPOP_REVREQUEST, 0, 1), + BPF_STMT(BPF_RET | BPF_K, sizeof(struct ether_arp) + + sizeof(struct ether_header)), + BPF_STMT(BPF_RET | BPF_K, 0), + }; + static struct bpf_program filter = { + sizeof insns / sizeof(insns[0]), + insns + }; + + fd = bpf_open(); + + /* Set immediate mode so packets are processed as they arrive. */ + immediate = 1; + if (ioctl(fd, BIOCIMMEDIATE, &immediate) < 0) { + err(FATAL, "BIOCIMMEDIATE: %s", strerror(errno)); + /* NOTREACHED */ + } + (void) strlcpy(ifr.ifr_name, device, sizeof ifr.ifr_name); + if (ioctl(fd, BIOCSETIF, (caddr_t) & ifr) < 0) { + err(FATAL, "BIOCSETIF: %s", strerror(errno)); + /* NOTREACHED */ + } + /* Check that the data link layer is an Ethernet; this code won't work + * with anything else. */ + if (ioctl(fd, BIOCGDLT, (caddr_t) & dlt) < 0) { + err(FATAL, "BIOCGDLT: %s", strerror(errno)); + /* NOTREACHED */ + } + if (dlt != DLT_EN10MB) { + err(FATAL, "%s is not an ethernet", device); + /* NOTREACHED */ + } + /* Set filter program. */ + if (ioctl(fd, BIOCSETF, (caddr_t) & filter) < 0) { + err(FATAL, "BIOCSETF: %s", strerror(errno)); + /* NOTREACHED */ + } + return fd; +} +/* + * Perform various sanity checks on the RARP request packet. Return + * false on failure and log the reason. + */ +static int +rarp_check(p, len) + u_char *p; + int len; +{ + struct ether_header *ep = (struct ether_header *) p; + struct ether_arp *ap = (struct ether_arp *) (p + sizeof(*ep)); + + (void) debug("got a packet"); + + if (len < sizeof(*ep) + sizeof(*ap)) { + err(NONFATAL, "truncated request"); + return 0; + } + /* XXX This test might be better off broken out... */ + if (ntohs (ep->ether_type) != ETHERTYPE_REVARP || + ntohs (ap->arp_hrd) != ARPHRD_ETHER || + ntohs (ap->arp_op) != ARPOP_REVREQUEST || + ntohs (ap->arp_pro) != ETHERTYPE_IP || + ap->arp_hln != 6 || ap->arp_pln != 4) { + err(NONFATAL, "request fails sanity check"); + return 0; + } + if (bcmp((char *) &ep->ether_shost, (char *) &ap->arp_sha, 6) != 0) { + err(NONFATAL, "ether/arp sender address mismatch"); + return 0; + } + if (bcmp((char *) &ap->arp_sha, (char *) &ap->arp_tha, 6) != 0) { + err(NONFATAL, "ether/arp target address mismatch"); + return 0; + } + return 1; +} + +/* + * 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 == 0) { + err(FATAL, "no interfaces"); + /* NOTREACHED */ + } + if (ioctl(iflist->ii_fd, BIOCGBLEN, (caddr_t) & bufsize) < 0) { + err(FATAL, "BIOCGBLEN: %s", strerror(errno)); + /* NOTREACHED */ + } + buf = (u_char *) malloc((unsigned) bufsize); + if (buf == 0) { + err(FATAL, "malloc: %s", strerror(errno)); + /* NOTREACHED */ + } + /* + * Find the highest numbered file descriptor for select(). + * Initialize the set of descriptors to listen to. + */ + FD_ZERO(&fds); + for (ii = iflist; ii; ii = ii->ii_next) { + FD_SET(ii->ii_fd, &fds); + if (ii->ii_fd > maxfd) + maxfd = ii->ii_fd; + } + while (1) { + listeners = fds; + if (select(maxfd + 1, &listeners, (struct fd_set *) 0, + (struct fd_set *) 0, (struct timeval *) 0) < 0) { + err(FATAL, "select: %s", strerror(errno)); + /* NOTREACHED */ + } + for (ii = iflist; ii; 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; + /* 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 && + (lseek(fd, 0, SEEK_CUR) + bufsize) < 0) { + (void) lseek(fd, 0, 0); + goto again; + } + err(FATAL, "read: %s", strerror(errno)); + /* NOTREACHED */ + } + /* Loop through the packet(s) */ +#define bhp ((struct bpf_hdr *)bp) + bp = buf; + ep = bp + cc; + while (bp < ep) { + register int caplen, hdrlen; + + caplen = bhp->bh_caplen; + hdrlen = bhp->bh_hdrlen; + if (rarp_check(bp + hdrlen, caplen)) + rarp_process(ii, bp + hdrlen); + bp += BPF_WORDALIGN(hdrlen + caplen); + } + } + } +} +#ifndef TFTP_DIR +#define TFTP_DIR "/tftpboot" +#endif + +/* + * 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) + in_addr_t addr; +{ + register struct dirent *dent; + register DIR *d; + char ipname[9]; + static DIR *dd = 0; + + (void) snprintf(ipname, sizeof(ipname), "%08X", addr); + /* If directory is already open, rewind it. Otherwise, open it. */ + if ((d = dd) != NULL) + rewinddir(d); + else { + if (chdir(TFTP_DIR) == -1) { + err(FATAL, "chdir: %s", strerror(errno)); + /* NOTREACHED */ + } + d = opendir("."); + if (d == 0) { + err(FATAL, "opendir: %s", strerror(errno)); + /* NOTREACHED */ + } + 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. + */ +in_addr_t +choose_ipaddr(alist, net, netmask) + in_addr_t **alist; + in_addr_t net; + in_addr_t 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) + struct if_info *ii; + u_char *pkt; +{ + struct ether_header *ep; + struct hostent *hp; + in_addr_t target_ipaddr; + char ename[256]; + struct in_addr in; + + ep = (struct ether_header *) pkt; + + if (ether_ntohost(ename, (struct ether_addr *)&ep->ether_shost) != 0 || + (hp = gethostbyname(ename)) == 0) + return; + + /* Choose correct address from list. */ + if (hp->h_addrtype != AF_INET) { + err(FATAL, "cannot handle non IP addresses"); + /* NOTREACHED */ + } + target_ipaddr = choose_ipaddr((in_addr_t **) hp->h_addr_list, + ii->ii_ipaddr & ii->ii_netmask, ii->ii_netmask); + + if (target_ipaddr == 0) { + in.s_addr = ii->ii_ipaddr & ii->ii_netmask; + err(NONFATAL, "cannot find %s on net %s\n", + ename, inet_ntoa(in)); + return; + } + if (rarp_bootable(htonl(target_ipaddr))) + rarp_reply(ii, ep, target_ipaddr); +} +/* + * Lookup the ethernet address of the interface attached to the BPF + * file descriptor 'fd'; return it in 'eaddr'. + */ +void +lookup_eaddr(ifname, eaddr) + char *ifname; + u_char *eaddr; +{ + char inbuf[8192]; + struct ifconf ifc; + struct ifreq *ifr; + struct sockaddr_dl *sdl; + int fd; + int i, len; + + /* We cannot use SIOCGIFADDR on the BPF descriptor. + We must instead get all the interfaces with SIOCGIFCONF + and find the right one. */ + + /* Use datagram socket to get Ethernet address. */ + if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { + err(FATAL, "socket: %s", strerror(errno)); + /* NOTREACHED */ + } + + ifc.ifc_len = sizeof(inbuf); + ifc.ifc_buf = inbuf; + if (ioctl(fd, SIOCGIFCONF, (caddr_t)&ifc) < 0 || + ifc.ifc_len < sizeof(struct ifreq)) { + err(FATAL, "lookup_eaddr: SIOGIFCONF: %s", strerror(errno)); + /* NOTREACHED */ + } + ifr = ifc.ifc_req; + for (i = 0; i < ifc.ifc_len; + i += len, ifr = (struct ifreq *)((caddr_t)ifr + len)) { + len = sizeof(ifr->ifr_name) + ifr->ifr_addr.sa_len; + sdl = (struct sockaddr_dl *)&ifr->ifr_addr; + if (sdl->sdl_family != AF_LINK || sdl->sdl_type != IFT_ETHER || + sdl->sdl_alen != 6) + continue; + if (!strncmp(ifr->ifr_name, ifname, sizeof(ifr->ifr_name))) { + bcopy((caddr_t)LLADDR(sdl), (caddr_t)eaddr, 6); + if (dflag) + fprintf(stderr, "%s: %x:%x:%x:%x:%x:%x\n", + ifr->ifr_name, eaddr[0], eaddr[1], + eaddr[2], eaddr[3], eaddr[4], eaddr[5]); + return; + } + } + + err(FATAL, "lookup_eaddr: Never saw interface `%s'!", ifname); +} +/* + * Lookup the IP address and network mask of the interface named 'ifname'. + */ +void +lookup_ipaddr(ifname, addrp, netmaskp) + char *ifname; + in_addr_t *addrp; + in_addr_t *netmaskp; +{ + int fd; + struct ifreq ifr; + + /* Use datagram socket to get IP address. */ + if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { + err(FATAL, "socket: %s", strerror(errno)); + /* NOTREACHED */ + } + (void) strlcpy(ifr.ifr_name, ifname, sizeof ifr.ifr_name); + if (ioctl(fd, SIOCGIFADDR, (char *) &ifr) < 0) { + err(FATAL, "SIOCGIFADDR: %s", strerror(errno)); + /* NOTREACHED */ + } + *addrp = ((struct sockaddr_in *) & ifr.ifr_addr)->sin_addr.s_addr; + if (ioctl(fd, SIOCGIFNETMASK, (char *) &ifr) < 0) { + perror("SIOCGIFNETMASK"); + exit(1); + } + *netmaskp = ((struct sockaddr_in *) & ifr.ifr_addr)->sin_addr.s_addr; + /* If SIOCGIFNETMASK didn't work, figure out a mask from the IP + * address class. */ + if (*netmaskp == 0) + *netmaskp = ipaddrtonetmask(*addrp); + + (void) close(fd); +} +/* + * 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). + */ +void +update_arptab(ep, ipaddr) + u_char *ep; + in_addr_t ipaddr; +{ + //int s; + 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; + /* This is needed #if defined(COMPAT_43) && BYTE_ORDER != BIG_ENDIAN, + because AF_UNSPEC is zero and the kernel assumes that a zero + sa_family means that the real sa_family value is in sa_len. */ + request.arp_ha.sa_len = 16; /* XXX */ + bcopy((char *) ep, (char *) request.arp_ha.sa_data, 6); + +#if 0 + s = socket(AF_INET, SOCK_DGRAM, 0); + if (ioctl(s, SIOCSARP, (caddr_t) & request) < 0) { + err(NONFATAL, "SIOCSARP: %s", strerror(errno)); + } + (void) close(s); +#endif +} +/* + * Build a reverse ARP packet and sent it out on the interface. + * 'ep' points to a valid ARPOP_REVREQUEST. The ARPOP_REVREPLY 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. + * + * ARPOP_REVREQUEST + * + * 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. + * + * ARPOP_REVREPLY + * + * 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) + struct if_info *ii; + struct ether_header *ep; + in_addr_t ipaddr; +{ + int n; + struct ether_arp *ap = (struct ether_arp *) (ep + 1); + int len; + + update_arptab((u_char *) & ap->arp_sha, ipaddr); + + /* Build the rarp reply by modifying the rarp request in place. */ + ep->ether_type = htons(ETHERTYPE_REVARP); + ap->ea_hdr.ar_hrd = htons(ARPHRD_ETHER); + ap->ea_hdr.ar_pro = htons(ETHERTYPE_IP); + ap->arp_op = htons(ARPOP_REVREPLY); + + 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); + + len = sizeof(*ep) + sizeof(*ap); + n = write(ii->ii_fd, (char *) ep, len); + if (n != len) { + err(NONFATAL, "write: only %d of %d bytes written", n, len); + } +} +/* + * Get the netmask of an IP address. This routine is used if + * SIOCGIFNETMASK doesn't work. + */ +in_addr_t +ipaddrtonetmask(addr) + in_addr_t addr; +{ + if (IN_CLASSA(addr)) + return IN_CLASSA_NET; + if (IN_CLASSB(addr)) + return IN_CLASSB_NET; + if (IN_CLASSC(addr)) + return IN_CLASSC_NET; + err(FATAL, "unknown IP address class: %08X", addr); + /* NOTREACHED */ + return 0; +} + +#if __STDC__ +#include <stdarg.h> +#else +#include <varargs.h> +#endif + +void +#if __STDC__ +err(int fatal, const char *fmt,...) +#else +err(fmt, va_alist) + int fatal; + char *fmt; +va_dcl +#endif +{ + va_list ap; +#if __STDC__ + va_start(ap, fmt); +#else + va_start(ap); +#endif + if (dflag) { + if (fatal) + (void) fprintf(stderr, "rarpd: error: "); + else + (void) fprintf(stderr, "rarpd: warning: "); + (void) vfprintf(stderr, fmt, ap); + (void) fprintf(stderr, "\n"); + } + vsyslog(LOG_ERR, fmt, ap); + va_end(ap); + if (fatal) + exit(1); + /* NOTREACHED */ +} + +void +#if __STDC__ +debug(const char *fmt,...) +#else +debug(fmt, va_alist) + char *fmt; +va_dcl +#endif +{ + va_list ap; + + if (dflag) { +#if __STDC__ + va_start(ap, fmt); +#else + va_start(ap); +#endif + (void) fprintf(stderr, "rarpd: "); + (void) vfprintf(stderr, fmt, ap); + va_end(ap); + (void) fprintf(stderr, "\n"); + } +} |