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dhcpd,dumpleases: write and use 64-bit current time in lease file.

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without it, determination of remaining lease time is unreliable.
 Yes, it's costly in code size, but without it, dumpleases output
 is misleading!

function                                             old     new   delta
read_leases                                          143     282    +139
dumpleases_main                                      447     572    +125
write_leases                                         193     233     +40
hton64                                                29      58     +29
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/0 up/down: 333/0)             Total: 333 bytes
This commit is contained in:
Denis Vlasenko 2009-02-01 00:40:45 +00:00
parent 49325969e7
commit 73121c3c8c
2 changed files with 52 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
networking/udhcp/dumpleases.c
View File

@ -6,14 +6,24 @@
#include "common.h"
#include "dhcpd.h"
#if BB_LITTLE_ENDIAN
static inline uint64_t hton64(uint64_t v)
{
return (((uint64_t)htonl(v)) << 32) | htonl(v >> 32);
}
#else
#define hton64(v) (v)
#endif
#define ntoh64(v) hton64(v)
int dumpleases_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int dumpleases_main(int argc UNUSED_PARAM, char **argv)
{
int fd;
int i;
unsigned opt;
leasetime_t expires;
leasetime_t curr;
int64_t written_at, curr, expires_abs;
const char *file = LEASES_FILE;
struct dhcpOfferedAddr lease;
struct in_addr addr;
@ -40,7 +50,13 @@ int dumpleases_main(int argc UNUSED_PARAM, char **argv)
printf("Mac Address IP-Address Expires %s\n", (opt & OPT_a) ? "at" : "in");
/* "00:00:00:00:00:00 255.255.255.255 Wed Jun 30 21:49:08 1993" */
if (full_read(fd, &written_at, sizeof(written_at)) != sizeof(written_at))
return 0;
written_at = ntoh64(written_at);
curr = time(NULL);
if (curr < written_at)
written_at = curr; /* lease file from future! :) */
while (full_read(fd, &lease, sizeof(lease)) == sizeof(lease)) {
const char *fmt = ":%02x" + 1;
for (i = 0; i < 6; i++) {
@ -49,13 +65,14 @@ int dumpleases_main(int argc UNUSED_PARAM, char **argv)
}
addr.s_addr = lease.yiaddr;
printf(" %-15s ", inet_ntoa(addr));
if (lease.expires == 0) {
expires_abs = ntohl(lease.expires) + written_at;
if (expires_abs <= curr) {
puts("expired");
continue;
}
expires = ntohl(lease.expires);
if (!(opt & OPT_a)) { /* no -a */
unsigned d, h, m;
unsigned expires = expires_abs - curr;
d = expires / (24*60*60); expires %= (24*60*60);
h = expires / (60*60); expires %= (60*60);
m = expires / 60; expires %= 60;
@ -63,7 +80,7 @@ int dumpleases_main(int argc UNUSED_PARAM, char **argv)
printf("%u days ", d);
printf("%02u:%02u:%02u\n", h, m, (unsigned)expires);
} else { /* -a */
time_t t = expires + curr;
time_t t = expires_abs;
fputs(ctime(&t), stdout);
}
}

37
networking/udhcp/files.c
View File

@ -12,6 +12,16 @@
#include "dhcpd.h"
#include "options.h"
#if BB_LITTLE_ENDIAN
static inline uint64_t hton64(uint64_t v)
{
return (((uint64_t)htonl(v)) << 32) | htonl(v >> 32);
}
#else
#define hton64(v) (v)
#endif
#define ntoh64(v) hton64(v)
/* on these functions, make sure your datatype matches */
static int read_ip(const char *line, void *arg)
@ -335,14 +345,16 @@ void FAST_FUNC write_leases(void)
int fd;
unsigned i;
leasetime_t curr;
int64_t written_at;
fd = open_or_warn(server_config.lease_file, O_WRONLY|O_CREAT|O_TRUNC);
if (fd < 0)
return;
curr = time(NULL);
//TODO: write out current time? Readers need to adjust .expires field
// to account for time between file was written and when it was read back.
curr = written_at = time(NULL);
written_at = hton64(written_at);
full_write(fd, &written_at, sizeof(written_at));
for (i = 0; i < server_config.max_leases; i++) {
leasetime_t tmp_time;
@ -353,11 +365,9 @@ void FAST_FUNC write_leases(void)
/* screw with the time in the struct, for easier writing */
tmp_time = leases[i].expires;
//if (server_config.remaining) {
leases[i].expires -= curr;
if ((signed_leasetime_t) leases[i].expires < 0)
leases[i].expires = 0;
//} /* else stick with the time we got */
leases[i].expires = htonl(leases[i].expires);
/* No error check. If the file gets truncated,
@ -382,14 +392,20 @@ void FAST_FUNC read_leases(const char *file)
{
int fd;
unsigned i;
// leasetime_t curr;
struct dhcpOfferedAddr lease;
int64_t written_at, curr;
fd = open_or_warn(file, O_RDONLY);
if (fd < 0)
return;
// curr = time(NULL);
if (full_read(fd, &written_at, sizeof(written_at)) != sizeof(written_at))
goto ret;
written_at = ntoh64(written_at);
curr = time(NULL);
if (curr < written_at)
written_at = curr; /* lease file from future! :) */
i = 0;
while (i < server_config.max_leases
&& full_read(fd, &lease, sizeof(lease)) == sizeof(lease)
@ -397,9 +413,9 @@ void FAST_FUNC read_leases(const char *file)
/* ADDME: what if it matches some static lease? */
uint32_t y = ntohl(lease.yiaddr);
if (y >= server_config.start_ip && y <= server_config.end_ip) {
leasetime_t expires = ntohl(lease.expires);
// if (!server_config.remaining)
// expires -= curr;
int64_t expires = ntohl(lease.expires) + written_at - curr;
if (expires <= 0)
continue;
/* NB: add_lease takes "relative time", IOW,
* lease duration, not lease deadline. */
if (!(add_lease(lease.chaddr, lease.yiaddr, expires))) {
@ -410,5 +426,6 @@ void FAST_FUNC read_leases(const char *file)
}
}
DEBUG("Read %d leases", i);
ret:
close(fd);
}