udhcpc: simplify renewal of the lease
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index eeef435..7138389 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -143,10 +143,7 @@
uint32_t xid = 0;
uint32_t lease_seconds = 0; /* can be given as 32-bit quantity */
int packet_num;
- /* t1, t2... what a wonderful names... */
- unsigned t1 = t1; /* for gcc */
- unsigned t2 = t2;
- unsigned timestamp_got_lease = timestamp_got_lease;
+ unsigned already_waited_sec;
unsigned opt;
int max_fd;
int retval;
@@ -337,6 +334,7 @@
udhcp_run_script(NULL, "deconfig");
change_listen_mode(LISTEN_RAW);
packet_num = 0;
+ already_waited_sec = 0;
/* Main event loop. select() waits on signal pipe and possibly
* on sockfd.
@@ -353,7 +351,7 @@
}
max_fd = udhcp_sp_fd_set(&rfds, sockfd);
- tv.tv_sec = timeout;
+ tv.tv_sec = timeout - already_waited_sec;
tv.tv_usec = 0;
retval = 0; /* If we already timed out, fall through, else... */
if (tv.tv_sec > 0) {
@@ -373,6 +371,9 @@
* resend discover/renew/whatever
*/
if (retval == 0) {
+ /* We will restart wait afresh in any case */
+ already_waited_sec = 0;
+
switch (state) {
case INIT_SELECTING:
if (packet_num < discover_retries) {
@@ -420,33 +421,29 @@
packet_num = 0;
continue;
case BOUND:
- /* Lease is starting to run out, time to enter renewing state */
+ /* Half of the lease passed, time to enter renewing state */
change_listen_mode(LISTEN_KERNEL);
DEBUG("Entering renew state");
state = RENEWING;
/* fall right through */
case RENEWING:
- /* Either set a new T1, or enter REBINDING state */
- if ((t2 - t1) > (lease_seconds / (4*60*60) + 1)) {
+ if (timeout > 60) {
/* send a request packet */
send_renew(xid, server_addr, requested_ip); /* unicast */
- t1 += (t2 - t1) / 2;
- timeout = t1 - ((unsigned)monotonic_sec() - timestamp_got_lease);
+ timeout >>= 1;
continue;
}
/* Timed out, enter rebinding state */
DEBUG("Entering rebinding state");
state = REBINDING;
- timeout = (t2 - t1);
continue;
case REBINDING:
/* Lease is *really* about to run out,
* try to find DHCP server using broadcast */
- if ((lease_seconds - t2) > (lease_seconds / (4*60*60) + 1)) {
+ if (timeout > 0) {
/* send a request packet */
send_renew(xid, 0, requested_ip); /* broadcast */
- t2 += (lease_seconds - t2) / 2;
- timeout = t2 - ((unsigned)monotonic_sec() - timestamp_got_lease);
+ timeout >>= 1;
continue;
}
/* Timed out, enter init state */
@@ -454,7 +451,7 @@
udhcp_run_script(NULL, "deconfig");
change_listen_mode(LISTEN_RAW);
state = INIT_SELECTING;
- timeout = 0;
+ /*timeout = 0; - already is */
packet_num = 0;
continue;
/* case RELEASED: */
@@ -477,7 +474,7 @@
/* If this packet will turn out to be unrelated/bogus,
* we will go back and wait for next one.
* Be sure timeout is properly decreased. */
- timeout -= (unsigned)monotonic_sec() - timestamp_before_wait;
+ already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
if (len == -1) { /* error is severe, reopen socket */
DEBUG("error on read, %s, reopening socket", strerror(errno));
@@ -523,6 +520,7 @@
state = REQUESTING;
timeout = 0;
packet_num = 0;
+ already_waited_sec = 0;
}
continue;
case RENEW_REQUESTED:
@@ -538,6 +536,7 @@
/* can be misaligned, thus memcpy */
memcpy(&lease_seconds, temp, 4);
lease_seconds = ntohl(lease_seconds);
+ lease_seconds &= 0x0fffffff; /* paranoia: must not be negative */
}
#if ENABLE_FEATURE_UDHCPC_ARPING
if (opt & OPT_a) {
@@ -557,20 +556,16 @@
requested_ip = 0;
timeout = tryagain_timeout;
packet_num = 0;
+ already_waited_sec = 0;
continue; /* back to main loop */
}
}
#endif
/* enter bound state */
- t1 = lease_seconds / 2;
-
- /* little fixed point for n * .875 */
- t2 = (lease_seconds * 7) >> 3;
+ timeout = lease_seconds / 2;
temp_addr.s_addr = packet.yiaddr;
bb_info_msg("Lease of %s obtained, lease time %u",
inet_ntoa(temp_addr), (unsigned)lease_seconds);
- timestamp_got_lease = monotonic_sec();
- timeout = t1;
requested_ip = packet.yiaddr;
udhcp_run_script(&packet,
((state == RENEWING || state == REBINDING) ? "renew" : "bound"));
@@ -585,6 +580,7 @@
if (!client_config.foreground)
client_background();
+ already_waited_sec = 0;
continue; /* back to main loop */
}
if (*message == DHCPNAK) {
@@ -599,6 +595,7 @@
requested_ip = 0;
timeout = 0;
packet_num = 0;
+ already_waited_sec = 0;
}
continue;
/* case BOUND, RELEASED: - ignore all packets */