networking/ping.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * $Id: ping.c,v 1.56 2004/03/15 08:28:48 andersen Exp $
   4  * Mini ping implementation for busybox
   5  *
   6  * Copyright (C) 1999 by Randolph Chung <tausq@debian.org>
   7  *
   8  * Adapted from the ping in netkit-base 0.10:
   9  * Copyright (c) 1989 The Regents of the University of California.
  10  * Derived from software contributed to Berkeley by Mike Muuss.
  11  *
  12  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  13  */
  14
  15 #include <sys/param.h>
  16 #include <sys/socket.h>
  17 #include <sys/file.h>
  18 #include <sys/time.h>
  19 #include <sys/times.h>
  20 #include <sys/signal.h>
  21
  22 #include <netinet/in.h>
  23 #include <netinet/ip.h>
  24 #include <netinet/ip_icmp.h>
  25 #include <arpa/inet.h>
  26 #include <netdb.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <errno.h>
  30 #include <unistd.h>
  31 #include <string.h>
  32 #include <stdlib.h>
  33 #include "busybox.h"
  34
  35
  36 static const int DEFDATALEN = 56;
  37 static const int MAXIPLEN = 60;
  38 static const int MAXICMPLEN = 76;
  39 static const int MAXPACKET = 65468;
  40 #define MAX_DUP_CHK     (8 * 128)
  41 static const int MAXWAIT = 10;
  42 static const int PINGINTERVAL = 1;              /* second */
  43
  44 #define O_QUIET         (1 << 0)
  45
  46 #define A(bit)          rcvd_tbl[(bit)>>3]      /* identify byte in array */
  47 #define B(bit)          (1 << ((bit) & 0x07))   /* identify bit in byte */
  48 #define SET(bit)        (A(bit) |= B(bit))
  49 #define CLR(bit)        (A(bit) &= (~B(bit)))
  50 #define TST(bit)        (A(bit) & B(bit))
  51
  52 static void ping(const char *host);
  53
  54 /* common routines */
  55 static int in_cksum(unsigned short *buf, int sz)
  56 {
  57         int nleft = sz;
  58         int sum = 0;
  59         unsigned short *w = buf;
  60         unsigned short ans = 0;
  61
  62         while (nleft > 1) {
  63                 sum += *w++;
  64                 nleft -= 2;
  65         }
  66
  67         if (nleft == 1) {
  68                 *(unsigned char *) (&ans) = *(unsigned char *) w;
  69                 sum += ans;
  70         }
  71
  72         sum = (sum >> 16) + (sum & 0xFFFF);
  73         sum += (sum >> 16);
  74         ans = ~sum;
  75         return (ans);
  76 }
  77
  78 /* simple version */
  79 #ifndef CONFIG_FEATURE_FANCY_PING
  80 static char *hostname = NULL;
  81 static void noresp(int ign)
  82 {
  83         printf("No response from %s\n", hostname);
  84         exit(EXIT_FAILURE);
  85 }
  86
  87 static void ping(const char *host)
  88 {
  89         struct hostent *h;
  90         struct sockaddr_in pingaddr;
  91         struct icmp *pkt;
  92         int pingsock, c;
  93         char packet[DEFDATALEN + MAXIPLEN + MAXICMPLEN];
  94
  95         pingsock = create_icmp_socket();
  96
  97         memset(&pingaddr, 0, sizeof(struct sockaddr_in));
  98
  99         pingaddr.sin_family = AF_INET;
 100         h = xgethostbyname(host);
 101         memcpy(&pingaddr.sin_addr, h->h_addr, sizeof(pingaddr.sin_addr));
 102         hostname = h->h_name;
 103
 104         pkt = (struct icmp *) packet;
 105         memset(pkt, 0, sizeof(packet));
 106         pkt->icmp_type = ICMP_ECHO;
 107         pkt->icmp_cksum = in_cksum((unsigned short *) pkt, sizeof(packet));
 108
 109         c = sendto(pingsock, packet, sizeof(packet), 0,
 110                            (struct sockaddr *) &pingaddr, sizeof(struct sockaddr_in));
 111
 112         if (c < 0 || c != sizeof(packet))
 113                 bb_perror_msg_and_die("sendto");
 114
 115         signal(SIGALRM, noresp);
 116         alarm(5);                                       /* give the host 5000ms to respond */
 117         /* listen for replies */
 118         while (1) {
 119                 struct sockaddr_in from;
 120                 socklen_t fromlen = sizeof(from);
 121
 122                 if ((c = recvfrom(pingsock, packet, sizeof(packet), 0,
 123                                                   (struct sockaddr *) &from, &fromlen)) < 0) {
 124                         if (errno == EINTR)
 125                                 continue;
 126                         bb_perror_msg("recvfrom");
 127                         continue;
 128                 }
 129                 if (c >= 76) {                  /* ip + icmp */
 130                         struct iphdr *iphdr = (struct iphdr *) packet;
 131
 132                         pkt = (struct icmp *) (packet + (iphdr->ihl << 2));     /* skip ip hdr */
 133                         if (pkt->icmp_type == ICMP_ECHOREPLY)
 134                                 break;
 135                 }
 136         }
 137         printf("%s is alive!\n", hostname);
 138         return;
 139 }
 140
 141 extern int ping_main(int argc, char **argv)
 142 {
 143         argc--;
 144         argv++;
 145         if (argc < 1)
 146                 bb_show_usage();
 147         ping(*argv);
 148         return EXIT_SUCCESS;
 149 }
 150
 151 #else /* ! CONFIG_FEATURE_FANCY_PING */
 152 /* full(er) version */
 153 static struct sockaddr_in pingaddr;
 154 static int pingsock = -1;
 155 static int datalen; /* intentionally uninitialized to work around gcc bug */
 156
 157 static long ntransmitted, nreceived, nrepeats, pingcount;
 158 static int myid, options;
 159 static unsigned long tmin = ULONG_MAX, tmax, tsum;
 160 static char rcvd_tbl[MAX_DUP_CHK / 8];
 161
 162 #ifndef CONFIG_FEATURE_FANCY_PING6
 163 static
 164 #endif
 165         struct hostent *hostent;
 166
 167 static void sendping(int);
 168 static void pingstats(int);
 169 static void unpack(char *, int, struct sockaddr_in *);
 170
 171 /**************************************************************************/
 172
 173 static void pingstats(int junk)
 174 {
 175         int status;
 176
 177         signal(SIGINT, SIG_IGN);
 178
 179         printf("\n--- %s ping statistics ---\n", hostent->h_name);
 180         printf("%ld packets transmitted, ", ntransmitted);
 181         printf("%ld packets received, ", nreceived);
 182         if (nrepeats)
 183                 printf("%ld duplicates, ", nrepeats);
 184         if (ntransmitted)
 185                 printf("%ld%% packet loss\n",
 186                            (ntransmitted - nreceived) * 100 / ntransmitted);
 187         if (nreceived)
 188                 printf("round-trip min/avg/max = %lu.%lu/%lu.%lu/%lu.%lu ms\n",
 189                            tmin / 10, tmin % 10,
 190                            (tsum / (nreceived + nrepeats)) / 10,
 191                            (tsum / (nreceived + nrepeats)) % 10, tmax / 10, tmax % 10);
 192         if (nreceived != 0)
 193                 status = EXIT_SUCCESS;
 194         else
 195                 status = EXIT_FAILURE;
 196         exit(status);
 197 }
 198
 199 static void sendping(int junk)
 200 {
 201         struct icmp *pkt;
 202         int i;
 203         char packet[datalen + sizeof(struct icmp)];
 204
 205         pkt = (struct icmp *) packet;
 206
 207         pkt->icmp_type = ICMP_ECHO;
 208         pkt->icmp_code = 0;
 209         pkt->icmp_cksum = 0;
 210         pkt->icmp_seq = htons(ntransmitted++);
 211         pkt->icmp_id = myid;
 212         CLR(ntohs(pkt->icmp_seq) % MAX_DUP_CHK);
 213
 214         gettimeofday((struct timeval *) &pkt->icmp_dun, NULL);
 215         pkt->icmp_cksum = in_cksum((unsigned short *) pkt, sizeof(packet));
 216
 217         i = sendto(pingsock, packet, sizeof(packet), 0,
 218                            (struct sockaddr *) &pingaddr, sizeof(struct sockaddr_in));
 219
 220         if (i < 0)
 221                 bb_perror_msg_and_die("sendto");
 222         else if ((size_t)i != sizeof(packet))
 223                 bb_error_msg_and_die("ping wrote %d chars; %d expected", i,
 224                            (int)sizeof(packet));
 225
 226         signal(SIGALRM, sendping);
 227         if (pingcount == 0 || ntransmitted < pingcount) {       /* schedule next in 1s */
 228                 alarm(PINGINTERVAL);
 229         } else {                                        /* done, wait for the last ping to come back */
 230                 /* todo, don't necessarily need to wait so long... */
 231                 signal(SIGALRM, pingstats);
 232                 alarm(MAXWAIT);
 233         }
 234 }
 235
 236 static char *icmp_type_name (int id)
 237 {
 238         switch (id) {
 239         case ICMP_ECHOREPLY:            return "Echo Reply";
 240         case ICMP_DEST_UNREACH:         return "Destination Unreachable";
 241         case ICMP_SOURCE_QUENCH:        return "Source Quench";
 242         case ICMP_REDIRECT:                     return "Redirect (change route)";
 243         case ICMP_ECHO:                         return "Echo Request";
 244         case ICMP_TIME_EXCEEDED:        return "Time Exceeded";
 245         case ICMP_PARAMETERPROB:        return "Parameter Problem";
 246         case ICMP_TIMESTAMP:            return "Timestamp Request";
 247         case ICMP_TIMESTAMPREPLY:       return "Timestamp Reply";
 248         case ICMP_INFO_REQUEST:         return "Information Request";
 249         case ICMP_INFO_REPLY:           return "Information Reply";
 250         case ICMP_ADDRESS:                      return "Address Mask Request";
 251         case ICMP_ADDRESSREPLY:         return "Address Mask Reply";
 252         default:                                        return "unknown ICMP type";
 253         }
 254 }
 255
 256 static void unpack(char *buf, int sz, struct sockaddr_in *from)
 257 {
 258         struct icmp *icmppkt;
 259         struct iphdr *iphdr;
 260         struct timeval tv, *tp;
 261         int hlen, dupflag;
 262         unsigned long triptime;
 263
 264         gettimeofday(&tv, NULL);
 265
 266         /* check IP header */
 267         iphdr = (struct iphdr *) buf;
 268         hlen = iphdr->ihl << 2;
 269         /* discard if too short */
 270         if (sz < (datalen + ICMP_MINLEN))
 271                 return;
 272
 273         sz -= hlen;
 274         icmppkt = (struct icmp *) (buf + hlen);
 275
 276         if (icmppkt->icmp_id != myid)
 277             return;                             /* not our ping */
 278
 279         if (icmppkt->icmp_type == ICMP_ECHOREPLY) {
 280                 u_int16_t recv_seq = ntohs(icmppkt->icmp_seq);
 281             ++nreceived;
 282                 tp = (struct timeval *) icmppkt->icmp_data;
 283
 284                 if ((tv.tv_usec -= tp->tv_usec) < 0) {
 285                         --tv.tv_sec;
 286                         tv.tv_usec += 1000000;
 287                 }
 288                 tv.tv_sec -= tp->tv_sec;
 289
 290                 triptime = tv.tv_sec * 10000 + (tv.tv_usec / 100);
 291                 tsum += triptime;
 292                 if (triptime < tmin)
 293                         tmin = triptime;
 294                 if (triptime > tmax)
 295                         tmax = triptime;
 296
 297                 if (TST(recv_seq % MAX_DUP_CHK)) {
 298                         ++nrepeats;
 299                         --nreceived;
 300                         dupflag = 1;
 301                 } else {
 302                         SET(recv_seq % MAX_DUP_CHK);
 303                         dupflag = 0;
 304                 }
 305
 306                 if (options & O_QUIET)
 307                         return;
 308
 309                 printf("%d bytes from %s: icmp_seq=%u", sz,
 310                            inet_ntoa(*(struct in_addr *) &from->sin_addr.s_addr),
 311                            recv_seq);
 312                 printf(" ttl=%d", iphdr->ttl);
 313                 printf(" time=%lu.%lu ms", triptime / 10, triptime % 10);
 314                 if (dupflag)
 315                         printf(" (DUP!)");
 316                 printf("\n");
 317         } else
 318                 if (icmppkt->icmp_type != ICMP_ECHO)
 319                         bb_error_msg("Warning: Got ICMP %d (%s)",
 320                                         icmppkt->icmp_type, icmp_type_name (icmppkt->icmp_type));
 321         fflush(stdout);
 322 }
 323
 324 static void ping(const char *host)
 325 {
 326         char packet[datalen + MAXIPLEN + MAXICMPLEN];
 327         int sockopt;
 328
 329         pingsock = create_icmp_socket();
 330
 331         memset(&pingaddr, 0, sizeof(struct sockaddr_in));
 332
 333         pingaddr.sin_family = AF_INET;
 334         hostent = xgethostbyname(host);
 335         if (hostent->h_addrtype != AF_INET)
 336                 bb_error_msg_and_die("unknown address type; only AF_INET is currently supported.");
 337
 338         memcpy(&pingaddr.sin_addr, hostent->h_addr, sizeof(pingaddr.sin_addr));
 339
 340         /* enable broadcast pings */
 341         sockopt = 1;
 342         setsockopt(pingsock, SOL_SOCKET, SO_BROADCAST, (char *) &sockopt,
 343                            sizeof(sockopt));
 344
 345         /* set recv buf for broadcast pings */
 346         sockopt = 48 * 1024;
 347         setsockopt(pingsock, SOL_SOCKET, SO_RCVBUF, (char *) &sockopt,
 348                            sizeof(sockopt));
 349
 350         printf("PING %s (%s): %d data bytes\n",
 351                    hostent->h_name,
 352                    inet_ntoa(*(struct in_addr *) &pingaddr.sin_addr.s_addr),
 353                    datalen);
 354
 355         signal(SIGINT, pingstats);
 356
 357         /* start the ping's going ... */
 358         sendping(0);
 359
 360         /* listen for replies */
 361         while (1) {
 362                 struct sockaddr_in from;
 363                 socklen_t fromlen = (socklen_t) sizeof(from);
 364                 int c;
 365
 366                 if ((c = recvfrom(pingsock, packet, sizeof(packet), 0,
 367                                                   (struct sockaddr *) &from, &fromlen)) < 0) {
 368                         if (errno == EINTR)
 369                                 continue;
 370                         bb_perror_msg("recvfrom");
 371                         continue;
 372                 }
 373                 unpack(packet, c, &from);
 374                 if (pingcount > 0 && nreceived >= pingcount)
 375                         break;
 376         }
 377         pingstats(0);
 378 }
 379
 380 extern int ping_main(int argc, char **argv)
 381 {
 382         char *thisarg;
 383
 384         datalen = DEFDATALEN; /* initialized here rather than in global scope to work around gcc bug */
 385
 386         argc--;
 387         argv++;
 388         options = 0;
 389         /* Parse any options */
 390         while (argc >= 1 && **argv == '-') {
 391                 thisarg = *argv;
 392                 thisarg++;
 393                 switch (*thisarg) {
 394                 case 'q':
 395                         options |= O_QUIET;
 396                         break;
 397                 case 'c':
 398                         if (--argc <= 0)
 399                                 bb_show_usage();
 400                         argv++;
 401                         pingcount = atoi(*argv);
 402                         break;
 403                 case 's':
 404                         if (--argc <= 0)
 405                                 bb_show_usage();
 406                         argv++;
 407                         datalen = atoi(*argv);
 408                         break;
 409                 default:
 410                         bb_show_usage();
 411                 }
 412                 argc--;
 413                 argv++;
 414         }
 415         if (argc < 1)
 416                 bb_show_usage();
 417
 418         myid = getpid() & 0xFFFF;
 419         ping(*argv);
 420         return EXIT_SUCCESS;
 421 }
 422 #endif /* ! CONFIG_FEATURE_FANCY_PING */