Ahem, I _said_ basic ping support.

1 files changed, 173 insertions, 48 deletions

diff --git a/toys/pending/ping.c b/toys/pending/ping.c
index 545ad79c..3802918d 100644
--- a/toys/pending/ping.c
+++ b/toys/pending/ping.c
@@ -3,8 +3,14 @@
  * 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>255c#<0s#<0>65535I:W#<0w#<0q46[-46]", TOYFLAG_ROOTONLY|TOYFLAG_USR|TOYFLAG_BIN))
+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"
@@ -16,16 +22,18 @@ config PING
     its response.
 
     Send ICMP ECHO_REQUEST packets to ipv4 or ipv6 addresses and prints each
-    echo it receives back, with round trip time.
+    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
+    -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, only displays output at start and when finished
-    -s SIZE     Packet SIZE in bytes (default 56)
-    -t TTL      Set Time (number of hops) To Live
-    -W SEC      Seconds to wait for response after all packets sent (default 10)
+    -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
 */
 
@@ -33,23 +41,44 @@ config PING
 #include "toys.h"
 
 #include <ifaddrs.h>
+#include <netinet/ip_icmp.h>
 
 GLOBALS(
-  long wait_exit;
-  long wait_resp;
-  char *iface;
-  long size;
-  long count;
-  long ttl;
+  long w;
+  long W;
+  char *i;
+  char *I;
+  long s;
+  long c;
+  long t;
 
   int sock;
+  long i_ms;
 )
 
-void *sock2addr(struct sockaddr *sa)
+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)
 {
-  if (sa->sa_family == AF_INET)
-    return &((struct sockaddr_in *)sa)->sin_addr;
-  return &((struct sockaddr_in6 *)sa)->sin6_addr;
+  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)
@@ -59,41 +88,55 @@ void ping_main(void)
   union {
     struct sockaddr_in in;
     struct sockaddr_in6 in6;
-  } src_addr;
-  struct sockaddr *sa = (void *)&src_addr;
-  int family = 0;
-
-  // no 4/6 specified: -I has only one, arg must match
-  // no 4/6 specified: arg is one, -I must match
-  // 4/6 specified, both must match
-
-  if (!(toys.optflags&FLAG_s)) TT.size = 56; // 64-PHDR_LEN
+  } 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.iface) {
-    if (!(toys.optflags&FLAG_6) && inet_pton(AF_INET, TT.iface,
+  if (TT.I) {
+    if (!(toys.optflags&FLAG_6) && inet_pton(AF_INET, TT.I,
       (void *)&src_addr.in.sin_addr))
-        family = sa->sa_family = AF_INET;
-    else if (!(toys.optflags&FLAG_4) && inet_pton(AF_INET6, TT.iface,
+        family = AF_INET;
+    else if (!(toys.optflags&FLAG_4) && inet_pton(AF_INET6, TT.I,
       (void *)&src_addr.in6.sin6_addr))
-        family = sa->sa_family = AF_INET6;
+        family = AF_INET6;
     else if (getifaddrs(&ifa2)) perror_exit("getifaddrs");
   }
 
-  // Look up HOST address, filtering for correct type.
+  // 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], 0, family, 0, 0, 0);
+  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;
-    if (!TT.iface || !ifa2) break;
+
+    // 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.iface)) continue;
+          || strcmp(ifa->ifa_name, TT.I)) continue;
       sa = (void *)ifa->ifa_addr;
 
       break;
@@ -102,19 +145,101 @@ void ping_main(void)
   }
 
   if (!ai)
-    error_exit("no v%d addr for -I %s", 4+2*(family==AF_INET6), TT.iface);
-
-  inet_ntop(family, sock2addr(sa), toybuf, sizeof(toybuf));
-  printf("host=%s\n", toybuf);
-  *toybuf = 0;
-  inet_ntop(ai->ai_family, sock2addr(ai->ai_addr), toybuf, sizeof(toybuf));
-  printf("targ=%s\n", toybuf);
-
-  // Open raw socket
-  TT.sock = xsocket(ai->ai_family, SOCK_DGRAM, (ifa->ifa_addr->sa_family == AF_INET) ?
-    IPPROTO_ICMP : IPPROTO_ICMPV6);
-  if (TT.iface && bind(TT.sock, ifa->ifa_addr, sizeof(src_addr)))
-    perror_exit("bind");
+    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);