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Add better comments to timeout.c.

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This commit is contained in:
Nicholas J. Kain 2011-06-29 20:08:32 -04:00
parent 3b5faebd6c
commit de47d3b4d6
1 changed files with 18 additions and 12 deletions
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30
ndhc/timeout.c
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@ -30,12 +30,15 @@
#include "random.h"
#define DELAY_SEC (((RETRY_DELAY - (RETRY_DELAY / NUMPACKETS)) / NUMPACKETS) + 1)
// Triggered after a DHCP discover packet has been sent and no reply has
// been received within the response wait time. If we've not exceeded the
// maximum number of discover retransmits, then send another packet and wait
// again. Otherwise, background or fail.
static void init_selecting_timeout(struct client_state_t *cs)
{
if (cs->packetNum < NUMPACKETS) {
if (cs->packetNum == 0)
cs->xid = libc_random_u32();
/* broadcast */
send_discover(cs->xid, cs->requestedIP);
cs->timeout = DELAY_SEC * (cs->packetNum + 1) * 1000;
cs->packetNum++;
@ -50,7 +53,6 @@ static void init_selecting_timeout(struct client_state_t *cs)
exit(EXIT_FAILURE);
}
}
/* wait to try again */
cs->packetNum = 0;
cs->timeout = RETRY_DELAY * 1000;
}
@ -65,7 +67,6 @@ static void renew_requested_timeout(struct client_state_t *cs)
cs->timeout = ((cs->packetNum == NUMPACKETS - 1) ? 10 : 2) * 1000;
cs->packetNum++;
} else {
/* timed out, go back to init state */
ifchange(NULL, IFCHANGE_DECONFIG);
cs->dhcpState = DS_INIT_SELECTING;
cs->timeout = 0;
@ -74,15 +75,17 @@ static void renew_requested_timeout(struct client_state_t *cs)
}
}
// Triggered after a DHCP lease request packet has been sent and no reply has
// been received within the response wait time. If we've not exceeded the
// maximum number of request retransmits, then send another packet and wait
// again. Otherwise, return to the DHCP initialization state.
static void requesting_timeout(struct client_state_t *cs)
{
if (cs->packetNum < NUMPACKETS) {
/* send broadcast request packet */
send_selecting(cs->xid, cs->serverAddr, cs->requestedIP);
cs->timeout = ((cs->packetNum == NUMPACKETS - 1) ? 10 : 2) * 1000;
cs->packetNum++;
} else {
/* timed out, go back to init state */
cs->dhcpState = DS_INIT_SELECTING;
cs->timeout = 0;
cs->packetNum = 0;
@ -90,26 +93,29 @@ static void requesting_timeout(struct client_state_t *cs)
}
}
// Triggered when a DHCP renew request has been sent and no reply has been
// received within the response wait time. This function is also directly
// called by bound_timeout() when it is time to renew a lease before it
// expires. Check to see if the lease is still valid, and if it is, send
// a unicast DHCP renew packet. If it is not, then change to the REBINDING
// state to get a new lease.
static void renewing_timeout(struct client_state_t *cs)
{
/* Either set a new T1, or enter DS_REBINDING state */
if ((cs->t2 - cs->t1) <= (cs->lease / 14400 + 1)) {
/* timed out, enter rebinding state */
cs->dhcpState = DS_REBINDING;
cs->timeout = (cs->t2 - cs->t1) * 1000;
log_line("Entering rebinding state.");
} else {
/* send a request packet */
send_renew(cs->xid, cs->serverAddr, cs->requestedIP); /* unicast */
send_renew(cs->xid, cs->serverAddr, cs->requestedIP);
cs->t1 = ((cs->t2 - cs->t1) >> 1) + cs->t1;
cs->timeout = (cs->t1 * 1000) - (curms() - cs->leaseStartTime);
}
}
// Triggered when the lease has been held for a significant fraction of its
// total time, and it is time to renew the lease so that it is not lost.
static void bound_timeout(struct client_state_t *cs)
{
/* Lease is starting to run out, time to enter renewing state */
cs->dhcpState = DS_RENEWING;
change_listen_mode(cs, LM_KERNEL);
log_line("Entering renew state.");
@ -136,7 +142,7 @@ static void rebinding_timeout(struct client_state_t *cs)
}
}
/* Handle epoll timeout expiring */
// Handle epoll timeout expiring
void handle_timeout(struct client_state_t *cs)
{
switch (cs->dhcpState) {