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