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Diffstat (limited to 'usr.sbin/rarpd/rarpd.c')
| -rw-r--r-- | usr.sbin/rarpd/rarpd.c | 951 |
1 files changed, 0 insertions, 951 deletions
diff --git a/usr.sbin/rarpd/rarpd.c b/usr.sbin/rarpd/rarpd.c deleted file mode 100644 index a500dd5..0000000 --- a/usr.sbin/rarpd/rarpd.c +++ /dev/null @@ -1,951 +0,0 @@ -/* - * Copyright (c) 1990, 1991, 1992, 1993, 1996 - * 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 - * - * 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. - */ - -#if 0 -#ifndef lint -static const char copyright[] = -"@(#) Copyright (c) 1990, 1991, 1992, 1993, 1996\n\ -The Regents of the University of California. All rights reserved.\n"; -#endif /* not lint */ -#endif -#include <sys/cdefs.h> -__FBSDID("$FreeBSD$"); - -/* - * rarpd - Reverse ARP Daemon - * - * Usage: rarpd -a [-dfsv] [-t directory] [hostname] - * rarpd [-dfsv] [-t directory] interface [hostname] - * - * 'hostname' is optional solely for backwards compatibility with Sun's rarpd. - * Currently, the argument is ignored. - */ -#include <sys/param.h> -#include <sys/file.h> -#include <sys/ioctl.h> -#include <sys/socket.h> -#include <sys/time.h> - -#include <net/bpf.h> -#include <net/ethernet.h> -#include <net/if.h> -#include <net/if_types.h> -#include <net/if_dl.h> -#include <net/route.h> - -#include <netinet/in.h> -#include <netinet/if_ether.h> - -#include <arpa/inet.h> - -#include <dirent.h> -#include <errno.h> -#include <ifaddrs.h> -#include <netdb.h> -#include <stdarg.h> -#include <stdio.h> -#include <string.h> -#include <syslog.h> -#include <stdlib.h> -#include <unistd.h> - -/* Cast a struct sockaddr to a struct sockaddr_in */ -#define SATOSIN(sa) ((struct sockaddr_in *)(sa)) - -#ifndef TFTP_DIR -#define TFTP_DIR "/tftpboot" -#endif - -#define ARPSECS (20 * 60) /* as per code in netinet/if_ether.c */ -#define REVARP_REQUEST ARPOP_REVREQUEST -#define REVARP_REPLY ARPOP_REVREPLY - -/* - * The structure for each interface. - */ -struct if_info { - struct if_info *ii_next; - int ii_fd; /* BPF file descriptor */ - in_addr_t ii_ipaddr; /* IP address */ - in_addr_t ii_netmask; /* subnet or net mask */ - u_char ii_eaddr[ETHER_ADDR_LEN]; /* ethernet address */ - char ii_ifname[IF_NAMESIZE]; -}; - -/* - * The list of all interfaces that are being listened to. rarp_loop() - * "selects" on the descriptors in this list. - */ -struct if_info *iflist; - -int verbose; /* verbose messages */ -const char *tftp_dir = TFTP_DIR; /* tftp directory */ - -int dflag; /* messages to stdout/stderr, not syslog(3) */ -int sflag; /* ignore /tftpboot */ - -static u_char zero[6]; - -static int bpf_open(void); -static in_addr_t choose_ipaddr(in_addr_t **, in_addr_t, in_addr_t); -static char *eatoa(u_char *); -static int expand_syslog_m(const char *fmt, char **newfmt); -static void init(char *); -static void init_one(struct ifaddrs *, char *, int); -static char *intoa(in_addr_t); -static in_addr_t ipaddrtonetmask(in_addr_t); -static void logmsg(int, const char *, ...) __printflike(2, 3); -static int rarp_bootable(in_addr_t); -static int rarp_check(u_char *, u_int); -static void rarp_loop(void); -static int rarp_open(char *); -static void rarp_process(struct if_info *, u_char *, u_int); -static void rarp_reply(struct if_info *, struct ether_header *, - in_addr_t, u_int); -static void update_arptab(u_char *, in_addr_t); -static void usage(void); - -int -main(int argc, char *argv[]) -{ - int op; - char *ifname, *hostname, *name; - - int aflag = 0; /* listen on "all" interfaces */ - int fflag = 0; /* don't fork */ - - if ((name = strrchr(argv[0], '/')) != NULL) - ++name; - else - name = argv[0]; - if (*name == '-') - ++name; - - /* - * All error reporting is done through syslog, unless -d is specified - */ - openlog(name, LOG_PID | LOG_CONS, LOG_DAEMON); - - opterr = 0; - while ((op = getopt(argc, argv, "adfst:v")) != -1) - switch (op) { - case 'a': - ++aflag; - break; - - case 'd': - ++dflag; - break; - - case 'f': - ++fflag; - break; - - case 's': - ++sflag; - break; - - case 't': - tftp_dir = optarg; - break; - - case 'v': - ++verbose; - break; - - default: - usage(); - /* NOTREACHED */ - } - argc -= optind; - argv += optind; - - ifname = (aflag == 0) ? argv[0] : NULL; - hostname = ifname ? argv[1] : argv[0]; - - if ((aflag && ifname) || (!aflag && ifname == NULL)) - usage(); - - init(ifname); - - if (!fflag) { - if (daemon(0,0)) { - logmsg(LOG_ERR, "cannot fork"); - exit(1); - } - } - rarp_loop(); - return(0); -} - -/* - * Add to the interface list. - */ -static void -init_one(struct ifaddrs *ifa, char *target, int pass1) -{ - struct if_info *ii, *ii2; - struct sockaddr_dl *ll; - int family; - - family = ifa->ifa_addr->sa_family; - switch (family) { - case AF_INET: - if (pass1) - /* Consider only AF_LINK during pass1. */ - return; - /* FALLTHROUGH */ - case AF_LINK: - if (!(ifa->ifa_flags & IFF_UP) || - (ifa->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT))) - return; - break; - default: - return; - } - - /* Don't bother going any further if not the target interface */ - if (target != NULL && strcmp(ifa->ifa_name, target) != 0) - return; - - /* Look for interface in list */ - for (ii = iflist; ii != NULL; ii = ii->ii_next) - if (strcmp(ifa->ifa_name, ii->ii_ifname) == 0) - break; - - if (pass1 && ii != NULL) - /* We've already seen that interface once. */ - return; - - /* Allocate a new one if not found */ - if (ii == NULL) { - ii = (struct if_info *)malloc(sizeof(*ii)); - if (ii == NULL) { - logmsg(LOG_ERR, "malloc: %m"); - exit(1); - } - bzero(ii, sizeof(*ii)); - ii->ii_fd = -1; - strlcpy(ii->ii_ifname, ifa->ifa_name, sizeof(ii->ii_ifname)); - ii->ii_next = iflist; - iflist = ii; - } else if (!pass1 && ii->ii_ipaddr != 0) { - /* - * Second AF_INET definition for that interface: clone - * the existing one, and work on that cloned one. - * This must be another IP address for this interface, - * so avoid killing the previous configuration. - */ - ii2 = (struct if_info *)malloc(sizeof(*ii2)); - if (ii2 == NULL) { - logmsg(LOG_ERR, "malloc: %m"); - exit(1); - } - memcpy(ii2, ii, sizeof(*ii2)); - ii2->ii_fd = -1; - ii2->ii_next = iflist; - iflist = ii2; - - ii = ii2; - } - - switch (family) { - case AF_INET: - ii->ii_ipaddr = SATOSIN(ifa->ifa_addr)->sin_addr.s_addr; - ii->ii_netmask = SATOSIN(ifa->ifa_netmask)->sin_addr.s_addr; - if (ii->ii_netmask == 0) - ii->ii_netmask = ipaddrtonetmask(ii->ii_ipaddr); - if (ii->ii_fd < 0) - ii->ii_fd = rarp_open(ii->ii_ifname); - break; - - case AF_LINK: - ll = (struct sockaddr_dl *)ifa->ifa_addr; - if (ll->sdl_type == IFT_ETHER) - bcopy(LLADDR(ll), ii->ii_eaddr, 6); - break; - } -} -/* - * Initialize all "candidate" interfaces that are in the system - * configuration list. A "candidate" is up, not loopback and not - * point to point. - */ -static void -init(char *target) -{ - struct if_info *ii, *nii, *lii; - struct ifaddrs *ifhead, *ifa; - int error; - - error = getifaddrs(&ifhead); - if (error) { - logmsg(LOG_ERR, "getifaddrs: %m"); - exit(1); - } - /* - * We make two passes over the list we have got. In the first - * one, we only collect AF_LINK interfaces, and initialize our - * list of interfaces from them. In the second pass, we - * collect the actual IP addresses from the AF_INET - * interfaces, and allow for the same interface name to appear - * multiple times (in case of more than one IP address). - */ - for (ifa = ifhead; ifa != NULL; ifa = ifa->ifa_next) - init_one(ifa, target, 1); - for (ifa = ifhead; ifa != NULL; ifa = ifa->ifa_next) - init_one(ifa, target, 0); - freeifaddrs(ifhead); - - /* Throw away incomplete interfaces */ - lii = NULL; - for (ii = iflist; ii != NULL; ii = nii) { - nii = ii->ii_next; - if (ii->ii_ipaddr == 0 || - bcmp(ii->ii_eaddr, zero, 6) == 0) { - if (lii == NULL) - iflist = nii; - else - lii->ii_next = nii; - if (ii->ii_fd >= 0) - close(ii->ii_fd); - free(ii); - continue; - } - lii = ii; - } - - /* Verbose stuff */ - if (verbose) - for (ii = iflist; ii != NULL; ii = ii->ii_next) - logmsg(LOG_DEBUG, "%s %s 0x%08x %s", - ii->ii_ifname, intoa(ntohl(ii->ii_ipaddr)), - (in_addr_t)ntohl(ii->ii_netmask), eatoa(ii->ii_eaddr)); -} - -static void -usage(void) -{ - (void)fprintf(stderr, "%s\n%s\n", - "usage: rarpd -a [-dfsv] [-t directory]", - " rarpd [-dfsv] [-t directory] interface"); - exit(1); -} - -static int -bpf_open(void) -{ - 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)sprintf(device, "/dev/bpf%d", n++); - fd = open(device, O_RDWR); - } while ((fd == -1) && (errno == EBUSY)); - - if (fd == -1) { - logmsg(LOG_ERR, "%s: %m", device); - exit(1); - } - 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. - */ -static int -rarp_open(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, REVARP_REQUEST, 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) == -1) { - logmsg(LOG_ERR, "BIOCIMMEDIATE: %m"); - exit(1); - } - strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); - if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) == -1) { - logmsg(LOG_ERR, "BIOCSETIF: %m"); - exit(1); - } - /* - * Check that the data link layer is an Ethernet; this code won't - * work with anything else. - */ - if (ioctl(fd, BIOCGDLT, (caddr_t)&dlt) == -1) { - logmsg(LOG_ERR, "BIOCGDLT: %m"); - exit(1); - } - if (dlt != DLT_EN10MB) { - logmsg(LOG_ERR, "%s is not an ethernet", device); - exit(1); - } - /* - * Set filter program. - */ - if (ioctl(fd, BIOCSETF, (caddr_t)&filter) == -1) { - logmsg(LOG_ERR, "BIOCSETF: %m"); - exit(1); - } - return fd; -} - -/* - * Perform various sanity checks on the RARP request packet. Return - * false on failure and log the reason. - */ -static int -rarp_check(u_char *p, u_int len) -{ - struct ether_header *ep = (struct ether_header *)p; - struct ether_arp *ap = (struct ether_arp *)(p + sizeof(*ep)); - - if (len < sizeof(*ep) + sizeof(*ap)) { - logmsg(LOG_ERR, "truncated request, got %u, expected %lu", - len, (u_long)(sizeof(*ep) + sizeof(*ap))); - 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) != REVARP_REQUEST || - ntohs(ap->arp_pro) != ETHERTYPE_IP || - ap->arp_hln != 6 || ap->arp_pln != 4) { - logmsg(LOG_DEBUG, "request fails sanity check"); - return 0; - } - if (bcmp((char *)&ep->ether_shost, (char *)&ap->arp_sha, 6) != 0) { - logmsg(LOG_DEBUG, "ether/arp sender address mismatch"); - return 0; - } - if (bcmp((char *)&ap->arp_sha, (char *)&ap->arp_tha, 6) != 0) { - logmsg(LOG_DEBUG, "ether/arp target address mismatch"); - return 0; - } - return 1; -} - -/* - * Loop indefinitely listening for RARP requests on the - * interfaces in 'iflist'. - */ -static void -rarp_loop(void) -{ - u_char *buf, *bp, *ep; - int cc, fd; - fd_set fds, listeners; - int bufsize, maxfd = 0; - struct if_info *ii; - - if (iflist == NULL) { - logmsg(LOG_ERR, "no interfaces"); - exit(1); - } - if (ioctl(iflist->ii_fd, BIOCGBLEN, (caddr_t)&bufsize) == -1) { - logmsg(LOG_ERR, "BIOCGBLEN: %m"); - exit(1); - } - buf = malloc(bufsize); - if (buf == NULL) { - logmsg(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) == -1) { - /* Don't choke when we get ptraced */ - if (errno == EINTR) - continue; - logmsg(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 == -1) && (errno == EINTR)) - goto again; - - /* Loop through the packet(s) */ -#define bhp ((struct bpf_hdr *)bp) - bp = buf; - ep = bp + cc; - while (bp < ep) { - 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. - */ -static int -rarp_bootable(in_addr_t addr) -{ - struct dirent *dent; - DIR *d; - char ipname[9]; - static DIR *dd = NULL; - - (void)sprintf(ipname, "%08X", (in_addr_t)ntohl(addr)); - - /* - * If directory is already open, rewind it. Otherwise, open it. - */ - if ((d = dd) != NULL) - rewinddir(d); - else { - if (chdir(tftp_dir) == -1) { - logmsg(LOG_ERR, "chdir: %s: %m", tftp_dir); - exit(1); - } - d = opendir("."); - if (d == NULL) { - logmsg(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. - */ -static in_addr_t -choose_ipaddr(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. - */ -static void -rarp_process(struct if_info *ii, u_char *pkt, u_int len) -{ - struct ether_header *ep; - struct hostent *hp; - in_addr_t target_ipaddr; - char ename[256]; - - ep = (struct ether_header *)pkt; - /* should this be arp_tha? */ - if (ether_ntohost(ename, (struct ether_addr *)&ep->ether_shost) != 0) { - logmsg(LOG_ERR, "cannot map %s to name", - eatoa(ep->ether_shost)); - return; - } - - if ((hp = gethostbyname(ename)) == NULL) { - logmsg(LOG_ERR, "cannot map %s to IP address", ename); - return; - } - - /* - * Choose correct address from list. - */ - if (hp->h_addrtype != AF_INET) { - logmsg(LOG_ERR, "cannot handle non IP addresses for %s", - ename); - return; - } - target_ipaddr = choose_ipaddr((in_addr_t **)hp->h_addr_list, - ii->ii_ipaddr & ii->ii_netmask, - ii->ii_netmask); - if (target_ipaddr == 0) { - logmsg(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) - logmsg(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). - */ -struct sockaddr_inarp sin_inarp = { - sizeof(struct sockaddr_inarp), AF_INET, 0, - {0}, - {0}, - 0, 0 -}; -struct sockaddr_dl sin_dl = { - sizeof(struct sockaddr_dl), AF_LINK, 0, IFT_ETHER, 0, 6, - 0, "" -}; -struct { - struct rt_msghdr rthdr; - char rtspace[512]; -} rtmsg; - -static void -update_arptab(u_char *ep, in_addr_t ipaddr) -{ - int cc; - struct sockaddr_inarp *ar, *ar2; - struct sockaddr_dl *ll, *ll2; - struct rt_msghdr *rt; - int xtype, xindex; - static pid_t pid; - int r; - static int seq; - - r = socket(PF_ROUTE, SOCK_RAW, 0); - if (r == -1) { - logmsg(LOG_ERR, "raw route socket: %m"); - exit(1); - } - pid = getpid(); - - 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) == -1) && (errno != ESRCH)) { - logmsg(LOG_ERR, "rtmsg get write: %m"); - close(r); - return; - } - do { - cc = read(r, rt, sizeof(rtmsg)); - } while (cc > 0 && (rt->rtm_seq != seq || rt->rtm_pid != pid)); - if (cc == -1) { - logmsg(LOG_ERR, "rtmsg get read: %m"); - close(r); - 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). - */ - logmsg(LOG_ERR, "bogus link family (%d) wrong net for %08X?\n", - ll2->sdl_family, ipaddr); - close(r); - 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) == -1) && (errno != EEXIST)) { - logmsg(LOG_ERR, "rtmsg add write: %m"); - close(r); - return; - } - do { - cc = read(r, rt, sizeof(rtmsg)); - } while (cc > 0 && (rt->rtm_seq != seq || rt->rtm_pid != pid)); - close(r); - if (cc == -1) { - logmsg(LOG_ERR, "rtmsg add read: %m"); - return; - } -} - -/* - * 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. - */ -static void -rarp_reply(struct if_info *ii, struct ether_header *ep, in_addr_t ipaddr, - u_int len) -{ - u_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) - logmsg(LOG_ERR, "write: only %d of %d bytes written", n, len); - if (verbose) - logmsg(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. - */ -static in_addr_t -ipaddrtonetmask(in_addr_t 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); - logmsg(LOG_DEBUG, "unknown IP address class: %08X", addr); - return htonl(0xffffffff); -} - -/* - * A faster replacement for inet_ntoa(). - */ -static char * -intoa(in_addr_t addr) -{ - char *cp; - u_int byte; - 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; -} - -static char * -eatoa(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); -} - -static void -logmsg(int pri, const char *fmt, ...) -{ - va_list v; - FILE *fp; - char *newfmt; - - va_start(v, fmt); - if (dflag) { - if (pri == LOG_ERR) - fp = stderr; - else - fp = stdout; - if (expand_syslog_m(fmt, &newfmt) == -1) { - vfprintf(fp, fmt, v); - } else { - vfprintf(fp, newfmt, v); - free(newfmt); - } - fputs("\n", fp); - fflush(fp); - } else { - vsyslog(pri, fmt, v); - } - va_end(v); -} - -static int -expand_syslog_m(const char *fmt, char **newfmt) { - const char *str, *m; - char *p, *np; - - p = strdup(""); - str = fmt; - while ((m = strstr(str, "%m")) != NULL) { - asprintf(&np, "%s%.*s%s", p, (int)(m - str), - str, strerror(errno)); - free(p); - if (np == NULL) { - errno = ENOMEM; - return (-1); - } - p = np; - str = m + 2; - } - - if (*str != '\0') { - asprintf(&np, "%s%s", p, str); - free(p); - if (np == NULL) { - errno = ENOMEM; - return (-1); - } - p = np; - } - - *newfmt = p; - return (0); -} |
