Logo Search packages:      
Sourcecode: cluster-agents version File versions  Download package

send_arp.linux.c

/*
 * arping.c
 *
 *          This program is free software; you can redistribute it and/or
 *          modify it under the terms of the GNU General Public License
 *          as published by the Free Software Foundation; either version
 *          2 of the License, or (at your option) any later version.
 *
 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 */

#include <stdlib.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <linux/sockios.h>
#include <sys/file.h>
#include <sys/time.h>
#include <sys/signal.h>
#include <sys/ioctl.h>
#include <linux/if.h>
#include <linux/if_packet.h>
#include <linux/if_ether.h>
#include <net/if_arp.h>
#include <sys/uio.h>

#include <netdb.h>
#include <unistd.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>

static void usage(void) __attribute__((noreturn));

static int quit_on_reply;
static char *device;
static int ifindex;
static char *source;
static struct in_addr src, dst;
static char *target;
static int dad = 0, unsolicited = 0, advert = 0;
static int quiet = 0;
static int count = -1;
static int timeout = 0;
static int unicasting = 0;
static int s = 0;
static int broadcast_only = 0;

static struct sockaddr_ll me;
static struct sockaddr_ll he;

static struct timeval start, last;

static int sent, brd_sent;
static int received, brd_recv, req_recv;

#define MS_TDIFF(tv1,tv2) ( ((tv1).tv_sec-(tv2).tv_sec)*1000 + \
                     ((tv1).tv_usec-(tv2).tv_usec)/1000 )

static void print_hex(unsigned char *p, int len);
static int recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM);
static void set_signal(int signo, void (*handler)(void));
static int send_pack(int s, struct in_addr src, struct in_addr dst,
            struct sockaddr_ll *ME, struct sockaddr_ll *HE);
static void finish(void);
static void catcher(void);

void usage(void)
{
      fprintf(stderr,
            "Usage: arping [-fqbDUAV] [-c count] [-w timeout] [-I device] [-s source] destination\n"
            "  -f : quit on first reply\n"
            "  -q : be quiet\n"
            "  -b : keep broadcasting, don't go unicast\n"
            "  -D : duplicate address detection mode\n"
            "  -U : Unsolicited ARP mode, update your neighbours\n"
            "  -A : ARP answer mode, update your neighbours\n"
            "  -V : print version and exit\n"
            "  -c count : how many packets to send\n"
            "  -w timeout : how long to wait for a reply\n"
            "  -I device : which ethernet device to use (eth0)\n"
            "  -s source : source ip address\n"
            "  destination : ask for what ip address\n"
            );
      exit(2);
}

void set_signal(int signo, void (*handler)(void))
{
      struct sigaction sa;

      memset(&sa, 0, sizeof(sa));
      sa.sa_handler = (void (*)(int))handler;
      sa.sa_flags = SA_RESTART;
      sigaction(signo, &sa, NULL);
}

int send_pack(int s, struct in_addr src, struct in_addr dst,
            struct sockaddr_ll *ME, struct sockaddr_ll *HE)
{
      int err;
      struct timeval now;
      unsigned char buf[256];
      struct arphdr *ah = (struct arphdr*)buf;
      unsigned char *p = (unsigned char *)(ah+1);

      ah->ar_hrd = htons(ME->sll_hatype);
      if (ah->ar_hrd == htons(ARPHRD_FDDI))
            ah->ar_hrd = htons(ARPHRD_ETHER);
      ah->ar_pro = htons(ETH_P_IP);
      ah->ar_hln = ME->sll_halen;
      ah->ar_pln = 4;
      ah->ar_op  = advert ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);

      memcpy(p, &ME->sll_addr, ah->ar_hln);
      p+=ME->sll_halen;

      memcpy(p, &src, 4);
      p+=4;

      if (advert)
            memcpy(p, &ME->sll_addr, ah->ar_hln);
      else
            memcpy(p, &HE->sll_addr, ah->ar_hln);
      p+=ah->ar_hln;

      memcpy(p, &dst, 4);
      p+=4;

      gettimeofday(&now, NULL);
      err = sendto(s, buf, p-buf, 0, (struct sockaddr*)HE, sizeof(*HE));
      if (err == p-buf) {
            last = now;
            sent++;
            if (!unicasting)
                  brd_sent++;
      }
      return err;
}

void finish(void)
{
      if (!quiet) {
            printf("Sent %d probes (%d broadcast(s))\n", sent, brd_sent);
            printf("Received %d response(s)", received);
            if (brd_recv || req_recv) {
                  printf(" (");
                  if (req_recv)
                        printf("%d request(s)", req_recv);
                  if (brd_recv)
                        printf("%s%d broadcast(s)",
                               req_recv ? ", " : "",
                               brd_recv);
                  printf(")");
            }
            printf("\n");
            fflush(stdout);
      }

      if (dad) {
          fflush(stdout);
          exit(!!received);
      }
      
      if (unsolicited)
            exit(0);

      fflush(stdout);
      exit(!received);
}

void catcher(void)
{
      struct timeval tv;

      gettimeofday(&tv, NULL);

      if (start.tv_sec==0)
            start = tv;

      if (count-- == 0 || (timeout && MS_TDIFF(tv,start) > timeout*1000 + 500))
            finish();

      if (last.tv_sec==0 || MS_TDIFF(tv,last) > 500) {
            send_pack(s, src, dst, &me, &he);
            if (count == 0 && unsolicited)
                  finish();
      }
      alarm(1);
}

void print_hex(unsigned char *p, int len)
{
      int i;
      for (i=0; i<len; i++) {
            printf("%02X", p[i]);
            if (i != len-1)
                  printf(":");
      }
}

int recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
{
      struct timeval tv;
      struct arphdr *ah = (struct arphdr*)buf;
      unsigned char *p = (unsigned char *)(ah+1);
      struct in_addr src_ip, dst_ip;

      gettimeofday(&tv, NULL);

      /* Filter out wild packets */
      if (FROM->sll_pkttype != PACKET_HOST &&
          FROM->sll_pkttype != PACKET_BROADCAST &&
          FROM->sll_pkttype != PACKET_MULTICAST)
            return 0;

      /* Only these types are recognised */
      if (ah->ar_op != htons(ARPOP_REQUEST) &&
          ah->ar_op != htons(ARPOP_REPLY))
            return 0;

      /* ARPHRD check and this darned FDDI hack here :-( */
      if (ah->ar_hrd != htons(FROM->sll_hatype) &&
          (FROM->sll_hatype != ARPHRD_FDDI || ah->ar_hrd != htons(ARPHRD_ETHER)))
            return 0;

      /* Protocol must be IP. */
      if (ah->ar_pro != htons(ETH_P_IP))
            return 0;
      if (ah->ar_pln != 4)
            return 0;
      if (ah->ar_hln != me.sll_halen)
            return 0;
      if (len < sizeof(*ah) + 2*(4 + ah->ar_hln))
            return 0;
      memcpy(&src_ip, p+ah->ar_hln, 4);
      memcpy(&dst_ip, p+ah->ar_hln+4+ah->ar_hln, 4);
      if (!dad) {
            if (src_ip.s_addr != dst.s_addr)
                  return 0;
            if (src.s_addr != dst_ip.s_addr)
                  return 0;
            if (memcmp(p+ah->ar_hln+4, &me.sll_addr, ah->ar_hln))
                  return 0;
      } else {
            /* DAD packet was:
               src_ip = 0 (or some src)
               src_hw = ME
               dst_ip = tested address
               dst_hw = <unspec>

               We fail, if receive request/reply with:
               src_ip = tested_address
               src_hw != ME
               if src_ip in request was not zero, check
               also that it matches to dst_ip, otherwise
               dst_ip/dst_hw do not matter.
             */
            if (src_ip.s_addr != dst.s_addr)
                  return 0;
            if (memcmp(p, &me.sll_addr, me.sll_halen) == 0)
                  return 0;
            if (src.s_addr && src.s_addr != dst_ip.s_addr)
                  return 0;
      }
      if (!quiet) {
            int s_printed = 0;
            printf("%s ", FROM->sll_pkttype==PACKET_HOST ? "Unicast" : "Broadcast");
            printf("%s from ", ah->ar_op == htons(ARPOP_REPLY) ? "reply" : "request");
            printf("%s [", inet_ntoa(src_ip));
            print_hex(p, ah->ar_hln);
            printf("] ");
            if (dst_ip.s_addr != src.s_addr) {
                  printf("for %s ", inet_ntoa(dst_ip));
                  s_printed = 1;
            }
            if (memcmp(p+ah->ar_hln+4, me.sll_addr, ah->ar_hln)) {
                  if (!s_printed)
                        printf("for ");
                  printf("[");
                  print_hex(p+ah->ar_hln+4, ah->ar_hln);
                  printf("]");
            }
            if (last.tv_sec) {
                  long usecs = (tv.tv_sec-last.tv_sec) * 1000000 +
                        tv.tv_usec-last.tv_usec;
                  long msecs = (usecs+500)/1000;
                  usecs -= msecs*1000 - 500;
                  printf(" %ld.%03ldms\n", msecs, usecs);
            } else {
                  printf(" UNSOLICITED?\n");
            }
            fflush(stdout);
      }
      received++;
      if (FROM->sll_pkttype != PACKET_HOST)
            brd_recv++;
      if (ah->ar_op == htons(ARPOP_REQUEST))
            req_recv++;
      if (quit_on_reply)
            finish();
      if(!broadcast_only) {
            memcpy(he.sll_addr, p, me.sll_halen);
            unicasting=1;
      }
      return 1;
}

#include <signal.h>

static void byebye(int nsig)
{
    /* Avoid an "error exit" log message if we're killed */
    nsig = 0;
    exit(nsig);
}

int
main(int argc, char **argv)
{
      int socket_errno;
      int ch;
      uid_t uid = getuid();
      int hb_mode = 0;

      signal(SIGTERM, byebye);
      signal(SIGPIPE, byebye);
      
      device = strdup("eth0");
      
      s = socket(PF_PACKET, SOCK_DGRAM, 0);
      socket_errno = errno;

      if (setuid(uid)) {
            perror("arping: setuid");
            exit(-1);
      }

      while ((ch = getopt(argc, argv, "h?bfDUAqc:w:s:I:Vr:i:p:")) != EOF) {
            switch(ch) {
            case 'b':
                  broadcast_only=1;
                  break;
            case 'D':
                  dad++;
                  quit_on_reply=1;
                  break;
            case 'U':
                  unsolicited++;
                  break;
            case 'A':
                  advert++;
                  unsolicited++;
                  break;
            case 'q':
                  quiet++;
                  break;
            case 'r': /* send_arp compatability option */
                  hb_mode = 1;
            case 'c':
                  count = atoi(optarg);
                  break;
            case 'w':
                  timeout = atoi(optarg);
                  break;
            case 'I':
                  device = optarg;
                  break;
            case 'f':
                  quit_on_reply=1;
                  break;
            case 's':
                  source = optarg;
                  break;
            case 'V':
                  printf("send_arp utility\n");
                  exit(0);
            case 'p':
            case 'i':
                hb_mode = 1;
                /* send_arp compatability options, ignore */
                break;
            case 'h':
            case '?':
            default:
                  usage();
            }
      }

      if(hb_mode) {
          /* send_arp compatability mode */
          if (argc - optind != 5) {
            usage();
            return 1;
          }
          /*
           *      argv[optind+1] DEVICE         dc0,eth0:0,hme0:0,
           *      argv[optind+2] IP       192.168.195.186
           *      argv[optind+3] MAC ADDR       00a0cc34a878
           *      argv[optind+4] BROADCAST      192.168.195.186
           *      argv[optind+5] NETMASK        ffffffffffff
           */

          unsolicited = 1;
          device = argv[optind];
          target = argv[optind+1];

      } else {
          argc -= optind;
          argv += optind;
          if (argc != 1)
            usage();

          target = *argv;
      }
      
      if (device == NULL) {
            fprintf(stderr, "arping: device (option -I) is required\n");
            usage();
      }

      if (s < 0) {
            errno = socket_errno;
            perror("arping: socket");
            exit(2);
      }

      if (1) {
            struct ifreq ifr;
            memset(&ifr, 0, sizeof(ifr));
            strncpy(ifr.ifr_name, device, IFNAMSIZ-1);
            if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
                  fprintf(stderr, "arping: unknown iface %s\n", device);
                  exit(2);
            }
            ifindex = ifr.ifr_ifindex;

            if (ioctl(s, SIOCGIFFLAGS, (char*)&ifr)) {
                  perror("ioctl(SIOCGIFFLAGS)");
                  exit(2);
            }
            if (!(ifr.ifr_flags&IFF_UP)) {
                  if (!quiet)
                        printf("Interface \"%s\" is down\n", device);
                  exit(2);
            }
            if (ifr.ifr_flags&(IFF_NOARP|IFF_LOOPBACK)) {
                  if (!quiet)
                        printf("Interface \"%s\" is not ARPable\n", device);
                  exit(dad?0:2);
            }
      }

      if (inet_aton(target, &dst) != 1) {
            struct hostent *hp;
            hp = gethostbyname2(target, AF_INET);
            if (!hp) {
                  fprintf(stderr, "arping: unknown host %s\n", target);
                  exit(2);
            }
            memcpy(&dst, hp->h_addr, 4);
      }

      if (source && inet_aton(source, &src) != 1) {
            fprintf(stderr, "arping: invalid source %s\n", source);
            exit(2);
      }

      if (!dad && unsolicited && src.s_addr == 0)
            src = dst;

      if (!dad || src.s_addr) {
            struct sockaddr_in saddr;
            int probe_fd = socket(AF_INET, SOCK_DGRAM, 0);

            if (probe_fd < 0) {
                  perror("socket");
                  exit(2);
            }
            if (device) {
                  if (setsockopt(probe_fd, SOL_SOCKET, SO_BINDTODEVICE, device, strlen(device)+1) == -1)
                        perror("WARNING: interface is ignored");
            }
            memset(&saddr, 0, sizeof(saddr));
            saddr.sin_family = AF_INET;
            if (src.s_addr) {
                  saddr.sin_addr = src;
                  if (bind(probe_fd, (struct sockaddr*)&saddr, sizeof(saddr)) == -1) {
                        perror("bind");
                        exit(2);
                  }
            } else if (!dad) {
                  int on = 1;
                  socklen_t alen = sizeof(saddr);

                  saddr.sin_port = htons(1025);
                  saddr.sin_addr = dst;

                  if (setsockopt(probe_fd, SOL_SOCKET, SO_DONTROUTE, (char*)&on, sizeof(on)) == -1)
                        perror("WARNING: setsockopt(SO_DONTROUTE)");
                  if (connect(probe_fd, (struct sockaddr*)&saddr, sizeof(saddr)) == -1) {
                        perror("connect");
                        exit(2);
                  }
                  if (getsockname(probe_fd, (struct sockaddr*)&saddr, &alen) == -1) {
                        perror("getsockname");
                        exit(2);
                  }
                  src = saddr.sin_addr;
            }
            close(probe_fd);
      };

      me.sll_family = AF_PACKET;
      me.sll_ifindex = ifindex;
      me.sll_protocol = htons(ETH_P_ARP);
      if (bind(s, (struct sockaddr*)&me, sizeof(me)) == -1) {
            perror("bind");
            exit(2);
      }

      if (1) {
            socklen_t alen = sizeof(me);
            if (getsockname(s, (struct sockaddr*)&me, &alen) == -1) {
                  perror("getsockname");
                  exit(2);
            }
      }
      if (me.sll_halen == 0) {
            if (!quiet)
                  printf("Interface \"%s\" is not ARPable (no ll address)\n", device);
            exit(dad?0:2);
      }

      he = me;
      memset(he.sll_addr, -1, he.sll_halen);

      if (!quiet) {
            printf("ARPING %s ", inet_ntoa(dst));
            printf("from %s %s\n",  inet_ntoa(src), device ? : "");
      }

      if (!src.s_addr && !dad) {
            fprintf(stderr, "arping: no source address in not-DAD mode\n");
            exit(2);
      }

      set_signal(SIGINT, finish);
      set_signal(SIGALRM, catcher);

      catcher();

      while(1) {
            sigset_t sset, osset;
            unsigned char packet[4096];
            struct sockaddr_ll from;
            socklen_t alen = sizeof(from);
            int cc;

            if ((cc = recvfrom(s, packet, sizeof(packet), 0,
                           (struct sockaddr *)&from, &alen)) < 0) {
                  perror("arping: recvfrom");
                  continue;
            }
            sigemptyset(&sset);
            sigaddset(&sset, SIGALRM);
            sigaddset(&sset, SIGINT);
            sigprocmask(SIG_BLOCK, &sset, &osset);
            recv_pack(packet, cc, &from);
            sigprocmask(SIG_SETMASK, &osset, NULL);
      }
}



Generated by  Doxygen 1.6.0   Back to index