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