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/times.h>
  19 #include <signal.h>
  20
  21 #include <netinet/in.h>
  22 #include <netinet/ip.h>
  23 #include <netinet/ip_icmp.h>
  24 #include <arpa/inet.h>
  25 #include <netdb.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <errno.h>
  29 #include <unistd.h>
  30 #include <string.h>
  31 #include <stdlib.h>
  32 #include "busybox.h"
  33
  34
  35 enum {
  36         DEFDATALEN = 56,
  37         MAXIPLEN = 60,
  38         MAXICMPLEN = 76,
  39         MAXPACKET = 65468,
  40         MAX_DUP_CHK = (8 * 128),
  41         MAXWAIT = 10,
  42         PINGINTERVAL = 1                /* second */
  43 };
  44
  45 #define O_QUIET         (1 << 0)
  46
  47 #define A(bit)          rcvd_tbl[(bit)>>3]      /* identify byte in array */
  48 #define B(bit)          (1 << ((bit) & 0x07))   /* identify bit in byte */
  49 #define SET(bit)        (A(bit) |= B(bit))
  50 #define CLR(bit)        (A(bit) &= (~B(bit)))
  51 #define TST(bit)        (A(bit) & B(bit))
  52
  53 static void ping(const char *host);
  54
  55 /* common routines */
  56 static int in_cksum(unsigned short *buf, int sz)
  57 {
  58         int nleft = sz;
  59         int sum = 0;
  60         unsigned short *w = buf;
  61         unsigned short ans = 0;
  62
  63         while (nleft > 1) {
  64                 sum += *w++;
  65                 nleft -= 2;
  66         }
  67
  68         if (nleft == 1) {
  69                 *(unsigned char *) (&ans) = *(unsigned char *) w;
  70                 sum += ans;
  71         }
  72
  73         sum = (sum >> 16) + (sum & 0xFFFF);
  74         sum += (sum >> 16);
  75         ans = ~sum;
  76         return (ans);
  77 }
  78
  79 /* simple version */
  80 #ifndef CONFIG_FEATURE_FANCY_PING
  81 static char *hostname = NULL;
  82 static void noresp(int ign)
  83 {
  84         printf("No response from %s\n", hostname);
  85         exit(EXIT_FAILURE);
  86 }
  87
  88 static void ping(const char *host)
  89 {
  90         struct hostent *h;
  91         struct sockaddr_in pingaddr;
  92         struct icmp *pkt;
  93         int pingsock, c;
  94         char packet[DEFDATALEN + MAXIPLEN + MAXICMPLEN];
  95
  96         pingsock = create_icmp_socket();
  97
  98         memset(&pingaddr, 0, sizeof(struct sockaddr_in));
  99
 100         pingaddr.sin_family = AF_INET;
 101         h = xgethostbyname(host);
 102         memcpy(&pingaddr.sin_addr, h->h_addr, sizeof(pingaddr.sin_addr));
 103         hostname = h->h_name;
 104
 105         pkt = (struct icmp *) packet;
 106         memset(pkt, 0, sizeof(packet));
 107         pkt->icmp_type = ICMP_ECHO;
 108         pkt->icmp_cksum = in_cksum((unsigned short *) pkt, sizeof(packet));
 109
 110         c = sendto(pingsock, packet, DEFDATALEN + ICMP_MINLEN, 0,
 111                            (struct sockaddr *) &pingaddr, sizeof(struct sockaddr_in));
 112
 113         if (c < 0) {
 114                 if (ENABLE_FEATURE_CLEAN_UP) close(pingsock);
 115                 bb_perror_msg_and_die("sendto");
 116         }
 117
 118         signal(SIGALRM, noresp);
 119         alarm(5);                                       /* give the host 5000ms to respond */
 120         /* listen for replies */
 121         while (1) {
 122                 struct sockaddr_in from;
 123                 socklen_t fromlen = sizeof(from);
 124
 125                 if ((c = recvfrom(pingsock, packet, sizeof(packet), 0,
 126                                                   (struct sockaddr *) &from, &fromlen)) < 0) {
 127                         if (errno == EINTR)
 128                                 continue;
 129                         bb_perror_msg("recvfrom");
 130                         continue;
 131                 }
 132                 if (c >= 76) {                  /* ip + icmp */
 133                         struct iphdr *iphdr = (struct iphdr *) packet;
 134
 135                         pkt = (struct icmp *) (packet + (iphdr->ihl << 2));     /* skip ip hdr */
 136                         if (pkt->icmp_type == ICMP_ECHOREPLY)
 137                                 break;
 138                 }
 139         }
 140         if (ENABLE_FEATURE_CLEAN_UP) close(pingsock);
 141         printf("%s is alive!\n", hostname);
 142         return;
 143 }
 144
 145 int ping_main(int argc, char **argv)
 146 {
 147         argc--;
 148         argv++;
 149         if (argc < 1)
 150                 bb_show_usage();
 151         ping(*argv);
 152         return EXIT_SUCCESS;
 153 }
 154
 155 #else /* ! CONFIG_FEATURE_FANCY_PING */
 156 /* full(er) version */
 157 static struct sockaddr_in pingaddr;
 158 static int pingsock = -1;
 159 static int datalen; /* intentionally uninitialized to work around gcc bug */
 160
 161 static long ntransmitted, nreceived, nrepeats, pingcount;
 162 static int myid, options;
 163 static unsigned long tmin = ULONG_MAX, tmax, tsum;
 164 static char rcvd_tbl[MAX_DUP_CHK / 8];
 165
 166 #ifndef CONFIG_FEATURE_FANCY_PING6
 167 static
 168 #endif
 169         struct hostent *hostent;
 170
 171 static void sendping(int);
 172 static void pingstats(int);
 173 static void unpack(char *, int, struct sockaddr_in *);
 174
 175 /**************************************************************************/
 176
 177 static void pingstats(int junk)
 178 {
 179         int status;
 180
 181         signal(SIGINT, SIG_IGN);
 182
 183         printf("\n--- %s ping statistics ---\n", hostent->h_name);
 184         printf("%ld packets transmitted, ", ntransmitted);
 185         printf("%ld packets received, ", nreceived);
 186         if (nrepeats)
 187                 printf("%ld duplicates, ", nrepeats);
 188         if (ntransmitted)
 189                 printf("%ld%% packet loss\n",
 190                            (ntransmitted - nreceived) * 100 / ntransmitted);
 191         if (nreceived)
 192                 printf("round-trip min/avg/max = %lu.%lu/%lu.%lu/%lu.%lu ms\n",
 193                            tmin / 10, tmin % 10,
 194                            (tsum / (nreceived + nrepeats)) / 10,
 195                            (tsum / (nreceived + nrepeats)) % 10, tmax / 10, tmax % 10);
 196         if (nreceived != 0)
 197                 status = EXIT_SUCCESS;
 198         else
 199                 status = EXIT_FAILURE;
 200         exit(status);
 201 }
 202
 203 static void sendping(int junk)
 204 {
 205         struct icmp *pkt;
 206         int i;
 207         char packet[datalen + ICMP_MINLEN];
 208
 209         pkt = (struct icmp *) packet;
 210
 211         pkt->icmp_type = ICMP_ECHO;
 212         pkt->icmp_code = 0;
 213         pkt->icmp_cksum = 0;
 214         pkt->icmp_seq = htons(ntransmitted++);
 215         pkt->icmp_id = myid;
 216         CLR(ntohs(pkt->icmp_seq) % MAX_DUP_CHK);
 217
 218         gettimeofday((struct timeval *) &pkt->icmp_dun, NULL);
 219         pkt->icmp_cksum = in_cksum((unsigned short *) pkt, sizeof(packet));
 220
 221         i = sendto(pingsock, packet, sizeof(packet), 0,
 222                            (struct sockaddr *) &pingaddr, sizeof(struct sockaddr_in));
 223
 224         if (i < 0)
 225                 bb_perror_msg_and_die("sendto");
 226         else if ((size_t)i != sizeof(packet))
 227                 bb_error_msg_and_die("ping wrote %d chars; %d expected", i,
 228                            (int)sizeof(packet));
 229
 230         signal(SIGALRM, sendping);
 231         if (pingcount == 0 || ntransmitted < pingcount) {       /* schedule next in 1s */
 232                 alarm(PINGINTERVAL);
 233         } else {                                        /* done, wait for the last ping to come back */
 234                 /* todo, don't necessarily need to wait so long... */
 235                 signal(SIGALRM, pingstats);
 236                 alarm(MAXWAIT);
 237         }
 238 }
 239
 240 static char *icmp_type_name (int id)
 241 {
 242         switch (id) {
 243         case ICMP_ECHOREPLY:            return "Echo Reply";
 244         case ICMP_DEST_UNREACH:         return "Destination Unreachable";
 245         case ICMP_SOURCE_QUENCH:        return "Source Quench";
 246         case ICMP_REDIRECT:                     return "Redirect (change route)";
 247         case ICMP_ECHO:                         return "Echo Request";
 248         case ICMP_TIME_EXCEEDED:        return "Time Exceeded";
 249         case ICMP_PARAMETERPROB:        return "Parameter Problem";
 250         case ICMP_TIMESTAMP:            return "Timestamp Request";
 251         case ICMP_TIMESTAMPREPLY:       return "Timestamp Reply";
 252         case ICMP_INFO_REQUEST:         return "Information Request";
 253         case ICMP_INFO_REPLY:           return "Information Reply";
 254         case ICMP_ADDRESS:                      return "Address Mask Request";
 255         case ICMP_ADDRESSREPLY:         return "Address Mask Reply";
 256         default:                                        return "unknown ICMP type";
 257         }
 258 }
 259
 260 static void unpack(char *buf, int sz, struct sockaddr_in *from)
 261 {
 262         struct icmp *icmppkt;
 263         struct iphdr *iphdr;
 264         struct timeval tv, *tp;
 265         int hlen, dupflag;
 266         unsigned long triptime;
 267
 268         gettimeofday(&tv, NULL);
 269
 270         /* check IP header */
 271         iphdr = (struct iphdr *) buf;
 272         hlen = iphdr->ihl << 2;
 273         /* discard if too short */
 274         if (sz < (datalen + ICMP_MINLEN))
 275                 return;
 276
 277         sz -= hlen;
 278         icmppkt = (struct icmp *) (buf + hlen);
 279
 280         if (icmppkt->icmp_id != myid)
 281             return;                             /* not our ping */
 282
 283         if (icmppkt->icmp_type == ICMP_ECHOREPLY) {
 284                 u_int16_t recv_seq = ntohs(icmppkt->icmp_seq);
 285             ++nreceived;
 286                 tp = (struct timeval *) icmppkt->icmp_data;
 287
 288                 if ((tv.tv_usec -= tp->tv_usec) < 0) {
 289                         --tv.tv_sec;
 290                         tv.tv_usec += 1000000;
 291                 }
 292                 tv.tv_sec -= tp->tv_sec;
 293
 294                 triptime = tv.tv_sec * 10000 + (tv.tv_usec / 100);
 295                 tsum += triptime;
 296                 if (triptime < tmin)
 297                         tmin = triptime;
 298                 if (triptime > tmax)
 299                         tmax = triptime;
 300
 301                 if (TST(recv_seq % MAX_DUP_CHK)) {
 302                         ++nrepeats;
 303                         --nreceived;
 304                         dupflag = 1;
 305                 } else {
 306                         SET(recv_seq % MAX_DUP_CHK);
 307                         dupflag = 0;
 308                 }
 309
 310                 if (options & O_QUIET)
 311                         return;
 312
 313                 printf("%d bytes from %s: icmp_seq=%u", sz,
 314                            inet_ntoa(*(struct in_addr *) &from->sin_addr.s_addr),
 315                            recv_seq);
 316                 printf(" ttl=%d", iphdr->ttl);
 317                 printf(" time=%lu.%lu ms", triptime / 10, triptime % 10);
 318                 if (dupflag)
 319                         printf(" (DUP!)");
 320                 printf("\n");
 321         } else
 322                 if (icmppkt->icmp_type != ICMP_ECHO)
 323                         bb_error_msg("Warning: Got ICMP %d (%s)",
 324                                         icmppkt->icmp_type, icmp_type_name (icmppkt->icmp_type));
 325         fflush(stdout);
 326 }
 327
 328 static void ping(const char *host)
 329 {
 330         char packet[datalen + MAXIPLEN + MAXICMPLEN];
 331         int sockopt;
 332
 333         pingsock = create_icmp_socket();
 334
 335         memset(&pingaddr, 0, sizeof(struct sockaddr_in));
 336
 337         pingaddr.sin_family = AF_INET;
 338         hostent = xgethostbyname(host);
 339         if (hostent->h_addrtype != AF_INET)
 340                 bb_error_msg_and_die("unknown address type; only AF_INET is currently supported.");
 341
 342         memcpy(&pingaddr.sin_addr, hostent->h_addr, sizeof(pingaddr.sin_addr));
 343
 344         /* enable broadcast pings */
 345         sockopt = 1;
 346         setsockopt(pingsock, SOL_SOCKET, SO_BROADCAST, (char *) &sockopt,
 347                            sizeof(sockopt));
 348
 349         /* set recv buf for broadcast pings */
 350         sockopt = 48 * 1024;
 351         setsockopt(pingsock, SOL_SOCKET, SO_RCVBUF, (char *) &sockopt,
 352                            sizeof(sockopt));
 353
 354         printf("PING %s (%s): %d data bytes\n",
 355                    hostent->h_name,
 356                    inet_ntoa(*(struct in_addr *) &pingaddr.sin_addr.s_addr),
 357                    datalen);
 358
 359         signal(SIGINT, pingstats);
 360
 361         /* start the ping's going ... */
 362         sendping(0);
 363
 364         /* listen for replies */
 365         while (1) {
 366                 struct sockaddr_in from;
 367                 socklen_t fromlen = (socklen_t) sizeof(from);
 368                 int c;
 369
 370                 if ((c = recvfrom(pingsock, packet, sizeof(packet), 0,
 371                                                   (struct sockaddr *) &from, &fromlen)) < 0) {
 372                         if (errno == EINTR)
 373                                 continue;
 374                         bb_perror_msg("recvfrom");
 375                         continue;
 376                 }
 377                 unpack(packet, c, &from);
 378                 if (pingcount > 0 && nreceived >= pingcount)
 379                         break;
 380         }
 381         pingstats(0);
 382 }
 383
 384 int ping_main(int argc, char **argv)
 385 {
 386         char *thisarg;
 387
 388         datalen = DEFDATALEN; /* initialized here rather than in global scope to work around gcc bug */
 389
 390         argc--;
 391         argv++;
 392         options = 0;
 393         /* Parse any options */
 394         while (argc >= 1 && **argv == '-') {
 395                 thisarg = *argv;
 396                 thisarg++;
 397                 switch (*thisarg) {
 398                 case 'q':
 399                         options |= O_QUIET;
 400                         break;
 401                 case 'c':
 402                         if (--argc <= 0)
 403                                 bb_show_usage();
 404                         argv++;
 405                         pingcount = atoi(*argv);
 406                         break;
 407                 case 's':
 408                         if (--argc <= 0)
 409                                 bb_show_usage();
 410                         argv++;
 411                         datalen = atoi(*argv);
 412                         break;
 413                 default:
 414                         bb_show_usage();
 415                 }
 416                 argc--;
 417                 argv++;
 418         }
 419         if (argc < 1)
 420                 bb_show_usage();
 421
 422         myid = getpid() & 0xFFFF;
 423         ping(*argv);
 424         return EXIT_SUCCESS;
 425 }
 426 #endif /* ! CONFIG_FEATURE_FANCY_PING */