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Perform timeout-based ARP retransmission for AS_GW_CHECK and AS_GW_QUERY.

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This commit is contained in:
Nicholas J. Kain 2011-07-05 11:07:42 -04:00
parent a9c807c1df
commit f1fcd4dc16
3 changed files with 49 additions and 26 deletions
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68
ndhc/arp.c
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@ -1,5 +1,5 @@
/* arp.c - arp ping checking
* Time-stamp: <2011-07-04 22:57:35 njk>
* Time-stamp: <2011-07-05 11:06:00 njk>
*
* Copyright 2010-2011 Nicholas J. Kain <njkain@gmail.com>
*
@ -332,7 +332,7 @@ int arp_gw_check(struct client_state_t *cs)
cs->arpPrevState = cs->dhcpState;
cs->dhcpState = DS_BOUND_GW_CHECK;
cs->oldTimeout = cs->timeout;
cs->timeout = 2000;
cs->timeout = ARP_RETRANS_DELAY + 250;
memset(&arp_dhcp_packet, 0, sizeof (struct dhcpmsg));
arpreply_clear();
return 0;
@ -346,6 +346,8 @@ static int arp_get_gw_hwaddr(struct client_state_t *cs)
log_line("arp: Searching for gw address...");
if (arp_ping(cs, cs->routerAddr) == -1)
return -1;
cs->oldTimeout = cs->timeout;
cs->timeout = ARP_RETRANS_DELAY + 250;
memset(&arp_dhcp_packet, 0, sizeof (struct dhcpmsg));
arpreply_clear();
return 0;
@ -361,10 +363,15 @@ static void arp_failed(struct client_state_t *cs)
void arp_gw_failed(struct client_state_t *cs)
{
log_line("arp: Gateway appears to have changed, getting new lease");
arp_close_fd(cs);
cs->oldTimeout = 0;
reinit_selecting(cs, 0);
if (arp_stats[arpState].count >= 3) {
log_line("arp: Gateway appears to have changed, getting new lease");
arp_close_fd(cs);
cs->oldTimeout = 0;
reinit_selecting(cs, 0);
return;
}
cs->timeout = ARP_RETRANS_DELAY + 250;
arp_retransmit(cs);
}
void arp_success(struct client_state_t *cs)
@ -377,14 +384,12 @@ void arp_success(struct client_state_t *cs)
cs->clientAddr = arp_dhcp_packet.yiaddr;
cs->dhcpState = DS_BOUND;
cs->init = 0;
ifchange_bind(&arp_dhcp_packet);
if (cs->arpPrevState == DS_RENEWING || cs->arpPrevState == DS_REBINDING) {
ifchange_bind(&arp_dhcp_packet);
arp_switch_state(cs, AS_DEFENSE);
} else {
ssize_t ol;
uint8_t *od;
od = get_option_data(&arp_dhcp_packet, DHCP_ROUTER, &ol);
ifchange_bind(&arp_dhcp_packet);
uint8_t *od = get_option_data(&arp_dhcp_packet, DHCP_ROUTER, &ol);
if (ol == 4) {
memcpy(&cs->routerAddr, od, 4);
arp_get_gw_hwaddr(cs);
@ -460,6 +465,31 @@ static int arp_is_query_reply(struct arpMsg *am)
return 1;
}
// Perform retransmission if necessary.
void arp_retransmit(struct client_state_t *cs)
{
if (curms() < arp_stats[arpState].ts + ARP_RETRANS_DELAY)
return;
log_line("DEBUG: retransmission timeout in arp state %u", arpState);
switch (arpState) {
case AS_GW_CHECK:
log_line("arp: Still waiting for gateway to reply to arp ping...");
arp_ping(cs, cs->routerAddr);
cs->timeout = ARP_RETRANS_DELAY + 250;
break;
case AS_GW_QUERY:
log_line("arp: Still looking for gateway hardware address...");
arp_ping(cs, cs->routerAddr);
cs->timeout = ARP_RETRANS_DELAY + 250;
break;
case AS_COLLISION_CHECK:
// XXX: send some additional checks after BOUND is set just to
// be safe?
default:
break;
}
}
void handle_arp_response(struct client_state_t *cs)
{
int r = 0;
@ -481,21 +511,8 @@ void handle_arp_response(struct client_state_t *cs)
}
log_line("DEBUG: Received %u bytes.", r);
// Perform retransmission if necessary.
if (r <= 0 && curms() >= arp_stats[arpState].ts + ARP_RETRANS_DELAY) {
log_line("DEBUG: retransmission timeout in arp state %u", arpState);
switch (arpState) {
case AS_COLLISION_CHECK: break;
case AS_GW_CHECK:
log_line("arp: Still waiting for gateway to reply to arp ping...");
arp_ping(cs, cs->routerAddr);
break;
case AS_GW_QUERY:
log_line("arp: Still looking for gateway hardware address...");
arp_ping(cs, cs->routerAddr);
default:
break;
}
if (r <= 0) {
arp_retransmit(cs);
return;
}
log_line("DEBUG: Did not retransmit.");
@ -540,6 +557,7 @@ void handle_arp_response(struct client_state_t *cs)
log_line("DEBUG: Doing work for AS_GW_QUERY state.");
if (arp_is_query_reply(&arpreply) &&
!memcmp(arpreply.sip4, &cs->routerAddr, 4)) {
cs->timeout = cs->oldTimeout;
memcpy(cs->routerArp, arpreply.smac, 6);
log_line("arp: Gateway hardware address %02x:%02x:%02x:%02x:%02x:%02x",
cs->routerArp[0], cs->routerArp[1],

3
ndhc/arp.h
View File

@ -1,5 +1,5 @@
/* arp.h - functions to call the interface change daemon
* Time-stamp: <2011-07-04 18:52:07 njk>
* Time-stamp: <2011-07-05 10:49:41 njk>
*
* Copyright 2010-2011 Nicholas J. Kain <njkain@gmail.com>
*
@ -50,6 +50,7 @@ int arp_check(struct client_state_t *cs, struct dhcpmsg *packet);
int arp_gw_check(struct client_state_t *cs);
void arp_success(struct client_state_t *cs);
void arp_gw_failed(struct client_state_t *cs);
void arp_retransmit(struct client_state_t *cs);
void handle_arp_response(struct client_state_t *cs);
#endif /* ARP_H_ */

4
ndhc/state.c
View File

@ -85,6 +85,10 @@ static void requesting_timeout(struct client_state_t *cs)
// 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)
{
arp_retransmit(cs);
if (curms() < cs->leaseStartTime + cs->renewTime * 1000)
return;
cs->dhcpState = DS_RENEWING;
set_listen_cooked(cs);
log_line("Entering renew state.");