aboutsummaryrefslogtreecommitdiff
path: root/toys/pending/ping.c
blob: 3802918d7b45bd8771708b992c4a2a42f8f7ab1d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
/* ping.c - check network connectivity
 *
 * Copyright 2014 Rob Landley <rob@landley.net>
 *
 * Not in SUSv4.
 *
 * Note: ping_group_range should never have existed. To disable it, do:
 *   echo 0 $(((1<<31)-1)) > /proc/sys/net/ipv4/ping_group_range
 * (Android does this by default in its init script.)
 *
 * Yes, I wimped out and capped -s at sizeof(toybuf), waiting for a complaint...
 
USE_PING(NEWTOY(ping, "<1>1t#<0>255=64c#<0=3s#<0>4088=56I:i:W#<0=10w#<0qf46[-46]", TOYFLAG_ROOTONLY|TOYFLAG_USR|TOYFLAG_BIN))
 
config PING
  bool "ping"
  default n
  help
    usage: ping [OPTIONS] HOST

    Check network connectivity by sending packets to a host and reporting
    its response.

    Send ICMP ECHO_REQUEST packets to ipv4 or ipv6 addresses and prints each
    echo it receives back, with round trip time. Returns true if host alive.

    Options:
    -4, -6      Force IPv4 or IPv6
    -c CNT      Send CNT many packets (default 3, 0 = infinite)
    -f          Flood (. on send, backspace on receive, to show packet drops)
    -i TIME     Interval between packets (default 1, need root for < .2)
    -I IFACE/IP Source interface or address
    -q          Quiet (stops after one returns true if host is alive)
    -s SIZE     Data SIZE in bytes (default 56)
    -t TTL      Set Time To Live (number of hops)
    -W SEC      Seconds to wait for response after -c (default 10)
    -w SEC      Exit after this many seconds
*/

#define FOR_ping 
#include "toys.h"

#include <ifaddrs.h>
#include <netinet/ip_icmp.h>

GLOBALS(
  long w;
  long W;
  char *i;
  char *I;
  long s;
  long c;
  long t;

  int sock;
  long i_ms;
)

static void xsendto(int sockfd, void *buf, size_t len, struct sockaddr *dest)
{
  int rc = sendto(TT.sock, buf, len, 0, dest,
    dest->sa_family == AF_INET ? sizeof(struct sockaddr_in) :
      sizeof(struct sockaddr_in6));

  if (rc != len) perror_exit("sendto");
}

// assumes aligned and can read even number of bytes
static unsigned short pingchksum(unsigned short *data, int len)
{
  unsigned short u = 0, d;

  // circular carry is endian independent: bits from high byte go to low byte
  while (len>0) {
    d = *data++;
    if (len == 1) d &= 255<<IS_BIG_ENDIAN;
    if (d >= (u += d)) u++;
    len -= 2;
  }

  return u;
}

void ping_main(void)
{
  struct addrinfo *ai, *ai2;
  struct ifaddrs *ifa, *ifa2 = 0;
  union {
    struct sockaddr_in in;
    struct sockaddr_in6 in6;
  } src_addr, src_addr2;
  struct sockaddr *sa = (void *)&src_addr, *sa2 = (void *)&src_addr2;
  struct pollfd pfd;
  int family = 0, sent = 0, len;
  long long tnext, tW, tnow, tw;
  unsigned short seq = 0;
  struct icmphdr *ih = (void *)toybuf;

  // Interval
  if (TT.i) {
    long frac;

    TT.i_ms = xparsetime(TT.i, 1000, &frac) * 1000;
    TT.i_ms += frac;
    if (TT.i_ms<200 && getuid()) error_exit("need root for -i <200");
  } else TT.i_ms = 1000;
  if (!(toys.optflags&FLAG_s)) TT.s = 56; // 64-PHDR_LEN

  // ipv4 or ipv6? (0 = autodetect if -I or arg have only one address type.)
  if (toys.optflags&FLAG_6) family = AF_INET6;
  else if (toys.optflags&FLAG_4) family = AF_INET;
  else family = 0;

  // If -I src_addr look it up. Allow numeric address of correct type.
  memset(&src_addr, 0, sizeof(src_addr));
  if (TT.I) {
    if (!(toys.optflags&FLAG_6) && inet_pton(AF_INET, TT.I,
      (void *)&src_addr.in.sin_addr))
        family = AF_INET;
    else if (!(toys.optflags&FLAG_4) && inet_pton(AF_INET6, TT.I,
      (void *)&src_addr.in6.sin6_addr))
        family = AF_INET6;
    else if (getifaddrs(&ifa2)) perror_exit("getifaddrs");
  }

  // Look up HOST address, filtering for correct type and interface.
  // If -I but no -46 then find compatible type between -I and HOST
  ai2 = xgetaddrinfo(*toys.optargs, 0, family, 0, 0, 0);
  for (ai = ai2; ai; ai = ai->ai_next) {

    // correct type?
    if (family && family!=ai->ai_family) continue;
    if (ai->ai_family!=AF_INET && ai->ai_family!=AF_INET6) continue;

    // correct interface?
    if (!TT.I || !ifa2) break;
    for (ifa = ifa2; ifa; ifa = ifa->ifa_next) {
      if (!ifa->ifa_addr || ifa->ifa_addr->sa_family!=ai->ai_family
          || strcmp(ifa->ifa_name, TT.I)) continue;
      sa = (void *)ifa->ifa_addr;

      break;
    }
    if (ifa) break;
  }

  if (!ai)
    error_exit("no v%d addr for -I %s", 4+2*(family==AF_INET6), TT.I);

  // Open DGRAM socket
  sa->sa_family = ai->ai_family;
  TT.sock = xsocket(ai->ai_family, SOCK_DGRAM,
    (ai->ai_family == AF_INET) ? IPPROTO_ICMP : IPPROTO_ICMPV6);
  if (TT.I && bind(TT.sock, sa, sizeof(src_addr))) perror_exit("bind");

  if (TT.t) {
    len = TT.t;

    if (ai->ai_family == AF_INET)
      setsockopt(TT.sock, IPPROTO_IP, IP_TTL, &len, 4);
    else setsockopt(TT.sock, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &len, 4);
  }

  if (!(toys.optflags&FLAG_q)) {
    printf("Ping %s (%s)", *toys.optargs, ntop(ai->ai_addr));
    if (TT.I) {
      *toybuf = 0;
      printf(" from %s (%s)", TT.I, ntop(sa));
    }
    // 20 byte TCP header, 8 byte ICMP header, plus data payload
    printf(": %ld(%ld) bytes.\n", TT.s, TT.s+28);
  }
  toys.exitval = 1;

  tW = tw = 0;
  tnext = millitime();
  if (TT.w) tw = TT.w*1000+tnext;

  // Send/receive packets
  for (;;) {
    int waitms = INT_MAX;

    // Exit due to timeout? (TODO: timeout is after last packet, waiting if
    // any packets ever dropped. Not timeout since packet was dropped.)
    tnow = millitime();
    if (tW) if (0>=(waitms = tW-tnow) || !sent) break;
    if (tw) {
      if (tnow>tw) break;
      else if (waitms>tw-tnow) waitms = tw-tnow;
    // Time to send the next packet?
    } else if (tnext-tnow <= 0) {
      tnext += TT.i_ms;

      memset(ih, 0, sizeof(*ih));
      ih->type = (ai->ai_family == AF_INET) ? 8 : 128;
      ih->un.echo.id = getpid();
      ih->un.echo.sequence = ++seq;
      if (TT.s >= 4) *(unsigned *)(ih+1) = tnow;

      ih->checksum = 0;
      ih->checksum = pingchksum((void *)toybuf, TT.s+sizeof(*ih));
      xsendto(TT.sock, toybuf, TT.s+sizeof(*ih), ai->ai_addr);
      sent++;
      if (toys.optflags&FLAG_f) printf(".");

      // last packet?
      if (TT.c) if (!--TT.c) {
        if (!TT.W) break;
        tW = tnow + TT.W*1000;
      }
    }

    // This is down here so it's against new period if we just sent a packet
    if (!tw && waitms>tnext-tnow) waitms = tnext-tnow;

    // wait for next packet or timeout

    if (waitms<0) waitms = 0;
    pfd.fd = TT.sock;
    pfd.events = POLLIN;
    if (0>(len = poll(&pfd, 1, waitms))) break;
    if (!len) continue;

    len = sizeof(src_addr2);
    len = recvfrom(TT.sock, toybuf, sizeof(toybuf), 0, sa2, (void *)&len);
    sent--;

    // reply id == 0 for ipv4, 129 for ipv6

    if (!(toys.optflags&FLAG_q)) {
      printf("%d bytes from %s: icmp_seq=%d ttl=%d", len, ntop(sa2),
             ih->un.echo.sequence, 0);
      if (len >= sizeof(*ih)+4) {
        unsigned lunchtime = millitime()-*(unsigned *)(ih+1);

        printf(" time=%u.%03u", lunchtime/1000, lunchtime%1000);
      }
      xputc('\n');
    }

    toys.exitval = 0;
  }

  if (CFG_TOYBOX_FREE) {
    freeaddrinfo(ai2);
    if (ifa2) freeifaddrs(ifa2);
  }
}