emo/ndhc
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Calculate the renewTime timeout more accurately: take the delay in ARP

Browse Source 
checking into account.

Rename t1 and t2 to renewTime and rebindTime.
This commit is contained in:
Nicholas J. Kain 2011-06-30 01:50:50 -04:00
parent d89e9f89c2
commit 8fffc5721f
4 changed files with 22 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
ndhc/arp.c
View File

@ -204,16 +204,10 @@ void arp_gw_failed(struct client_state_t *cs)
void arp_success(struct client_state_t *cs)
{
struct in_addr temp_addr;
arp_close_fd(cs);
cs->timeout = (cs->renewTime * 1000) - (curms() - cs->leaseStartTime);
cs->t1 = cs->lease >> 1;
cs->t2 = (cs->lease * 0x7) >> 3; // T2 = lease * 0.875
cs->timeout = cs->t1 * 1000;
cs->leaseStartTime = curms();
temp_addr.s_addr = arp_dhcp_packet.yiaddr;
struct in_addr temp_addr = {.s_addr = arp_dhcp_packet.yiaddr};
log_line("arp: Lease of %s obtained, lease time %ld",
inet_ntoa(temp_addr), cs->lease);
cs->requestedIP = arp_dhcp_packet.yiaddr;

2
ndhc/config.h
View File

@ -50,7 +50,7 @@ struct client_state_t {
int epollFd, signalFd, listenFd, arpFd, nlFd;
int timeout, oldTimeout;
uint32_t requestedIP, serverAddr, routerAddr;
uint32_t lease, t1, t2, xid;
uint32_t lease, renewTime, rebindTime, xid;
uint8_t routerArp[6];
uint8_t init;
};

4
ndhc/ndhc.c
View File

@ -74,8 +74,8 @@ struct client_state_t cs = {
.serverAddr = 0,
.routerAddr = 0,
.lease = 0,
.t1 = 0,
.t2 = 0,
.renewTime = 0,
.rebindTime = 0,
.epollFd = -1,
.signalFd = -1,
.listenFd = -1,

30
ndhc/state.c
View File

@ -83,21 +83,21 @@ static void bound_timeout(struct client_state_t *cs)
// state to get a new lease.
static void renewing_timeout(struct client_state_t *cs)
{
if ((cs->t2 - cs->t1) <= (cs->lease / 14400 + 1)) {
if ((cs->rebindTime - cs->renewTime) <= (cs->lease / 14400 + 1)) {
cs->dhcpState = DS_REBINDING;
cs->timeout = (cs->t2 - cs->t1) * 1000;
cs->timeout = (cs->rebindTime - cs->renewTime) * 1000;
log_line("Entering rebinding state.");
} else {
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);
cs->renewTime = ((cs->rebindTime - cs->renewTime) >> 1) + cs->renewTime;
cs->timeout = (cs->renewTime * 1000) - (curms() - cs->leaseStartTime);
}
}
static void rebinding_timeout(struct client_state_t *cs)
{
/* Either set a new T2, or enter INIT state */
if ((cs->lease - cs->t2) <= (cs->lease / 14400 + 1)) {
/* Either set a new rebindTime, or enter INIT state */
if ((cs->lease - cs->rebindTime) <= (cs->lease / 14400 + 1)) {
/* timed out, enter init state */
cs->dhcpState = DS_SELECTING;
log_line("Lease lost, entering init state.");
@ -109,8 +109,8 @@ static void rebinding_timeout(struct client_state_t *cs)
/* send a request packet */
send_renew(cs->xid, 0, cs->requestedIP); /* broadcast */
cs->t2 = ((cs->lease - cs->t2) >> 1) + cs->t2;
cs->timeout = (cs->t2 * 1000) - (curms() - cs->leaseStartTime);
cs->rebindTime = ((cs->lease - cs->rebindTime) >> 1) + cs->rebindTime;
cs->timeout = (cs->rebindTime * 1000) - (curms() - cs->leaseStartTime);
}
}
@ -122,20 +122,24 @@ static void released_timeout(struct client_state_t *cs)
static void an_packet(struct client_state_t *cs, struct dhcpmsg *packet,
uint8_t *message)
{
uint8_t *temp = NULL;
ssize_t optlen;
if (*message == DHCPACK) {
uint8_t *temp = NULL;
ssize_t optlen;
cs->leaseStartTime = curms();
if (!(temp = get_option_data(packet, DHCP_LEASE_TIME, &optlen))) {
log_line("No lease time received, assuming 1h.");
cs->lease = 60 * 60;
} else {
memcpy(&cs->lease, temp, 4);
cs->lease = ntohl(cs->lease);
// Enforce upper and lower bounds on lease.
cs->lease &= 0x0fffffff;
if (cs->lease < RETRY_DELAY)
cs->lease = RETRY_DELAY;
}
// Always use RFC2131 'default' values. It's not worth validating
// the remote server values, if they even exist, for sanity.
cs->renewTime = cs->lease >> 1;
cs->rebindTime = (cs->lease * 0x7) >> 3; // * 0.875
// Can transition from DS_ARP_CHECK to DS_BOUND or DS_SELECTING.
if (arp_check(cs, packet) == -1) {
@ -164,9 +168,9 @@ static void an_packet(struct client_state_t *cs, struct dhcpmsg *packet,
static void selecting_packet(struct client_state_t *cs, struct dhcpmsg *packet,
uint8_t *message)
{
uint8_t *temp = NULL;
ssize_t optlen;
if (*message == DHCPOFFER) {
uint8_t *temp = NULL;
ssize_t optlen;
if ((temp = get_option_data(packet, DHCP_SERVER_ID, &optlen))) {
memcpy(&cs->serverAddr, temp, 4);
cs->xid = packet->xid;