networking/udhcp/dumpleases.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
   4  */
   5
   6 #include "common.h"
   7 #include "dhcpd.h"
   8
   9 #if BB_LITTLE_ENDIAN
  10 static inline uint64_t hton64(uint64_t v)
  11 {
  12         return (((uint64_t)htonl(v)) << 32) | htonl(v >> 32);
  13 }
  14 #else
  15 #define hton64(v) (v)
  16 #endif
  17 #define ntoh64(v) hton64(v)
  18
  19
  20 int dumpleases_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  21 int dumpleases_main(int argc UNUSED_PARAM, char **argv)
  22 {
  23         int fd;
  24         int i;
  25         unsigned opt;
  26         int64_t written_at, curr, expires_abs;
  27         const char *file = LEASES_FILE;
  28         struct dhcpOfferedAddr lease;
  29         struct in_addr addr;
  30
  31         enum {
  32                 OPT_a   = 0x1,  // -a
  33                 OPT_r   = 0x2,  // -r
  34                 OPT_f   = 0x4,  // -f
  35         };
  36 #if ENABLE_GETOPT_LONG
  37         static const char dumpleases_longopts[] ALIGN1 =
  38                 "absolute\0"  No_argument       "a"
  39                 "remaining\0" No_argument       "r"
  40                 "file\0"      Required_argument "f"
  41                 ;
  42
  43         applet_long_options = dumpleases_longopts;
  44 #endif
  45         opt_complementary = "=0:a--r:r--a";
  46         opt = getopt32(argv, "arf:", &file);
  47
  48         fd = xopen(file, O_RDONLY);
  49
  50         printf("Mac Address       IP Address      Host Name           Expires %s\n", (opt & OPT_a) ? "at" : "in");
  51         /*     "00:00:00:00:00:00 255.255.255.255 ABCDEFGHIJKLMNOPQRS Wed Jun 30 21:49:08 1993" */
  52         /*     "123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789 */
  53
  54         if (full_read(fd, &written_at, sizeof(written_at)) != sizeof(written_at))
  55                 return 0;
  56         written_at = ntoh64(written_at);
  57         curr = time(NULL);
  58         if (curr < written_at)
  59                 written_at = curr; /* lease file from future! :) */
  60
  61         while (full_read(fd, &lease, sizeof(lease)) == sizeof(lease)) {
  62                 const char *fmt = ":%02x" + 1;
  63                 for (i = 0; i < 6; i++) {
  64                         printf(fmt, lease.chaddr[i]);
  65                         fmt = ":%02x";
  66                 }
  67                 addr.s_addr = lease.yiaddr;
  68                 /* actually, 15+1 and 19+1, +1 is a space between columns */
  69                 /* lease.hostname is char[20] and is always NUL terminated */
  70                 printf(" %-16s%-20s", inet_ntoa(addr), lease.hostname);
  71                 expires_abs = ntohl(lease.expires) + written_at;
  72                 if (expires_abs <= curr) {
  73                         puts("expired");
  74                         continue;
  75                 }
  76                 if (!(opt & OPT_a)) { /* no -a */
  77                         unsigned d, h, m;
  78                         unsigned expires = expires_abs - curr;
  79                         d = expires / (24*60*60); expires %= (24*60*60);
  80                         h = expires / (60*60); expires %= (60*60);
  81                         m = expires / 60; expires %= 60;
  82                         if (d)
  83                                 printf("%u days ", d);
  84                         printf("%02u:%02u:%02u\n", h, m, (unsigned)expires);
  85                 } else { /* -a */
  86                         time_t t = expires_abs;
  87                         fputs(ctime(&t), stdout);
  88                 }
  89         }
  90         /* close(fd); */
  91
  92         return 0;
  93 }