void arp_request(void)
{
if ((net_arp_wait_packet_ip.s_addr & net_netmask.s_addr) !=
(net_ip.s_addr & net_netmask.s_addr)) {
if (net_gateway.s_addr == 0) {
puts("## Warning: gatewayip needed but not set\n");
net_arp_wait_reply_ip = net_arp_wait_packet_ip;
} else {
net_arp_wait_reply_ip = net_gateway;
}
} else {
net_arp_wait_reply_ip = net_arp_wait_packet_ip;
}
arp_raw_request(net_ip, net_null_ethaddr, net_arp_wait_reply_ip);
}
void ArpRequest(void)
{
if ((NetArpWaitPacketIP & NetOurSubnetMask) !=
(NetOurIP & NetOurSubnetMask)) {
if (NetOurGatewayIP == 0) {
puts("## Warning: gatewayip needed but not set\n");
NetArpWaitReplyIP = NetArpWaitPacketIP;
} else {
NetArpWaitReplyIP = NetOurGatewayIP;
}
} else {
NetArpWaitReplyIP = NetArpWaitPacketIP;
}
arp_raw_request(NetOurIP, NetEtherNullAddr, NetArpWaitReplyIP);
}
void link_local_receive_arp(struct arp_hdr *arp, int len)
{
int source_ip_conflict;
int target_ip_conflict;
if (state == DISABLED)
return;
/* We need to adjust the timeout in case we didn't receive a
conflicting packet. */
if (timeout_ms > 0) {
unsigned diff = deadline_ms - MONOTONIC_MS();
if ((int)(diff) < 0) {
/* Current time is greater than the expected timeout
time. This should never happen */
debug_cond(DEBUG_LL_STATE,
"missed an expected timeout\n");
timeout_ms = 0;
} else {
debug_cond(DEBUG_INT_STATE, "adjusting timeout\n");
timeout_ms = diff | 1; /* never 0 */
}
}
/*
* XXX Don't bother with ethernet link just yet
if ((fds[0].revents & POLLIN) == 0) {
if (fds[0].revents & POLLERR) {
// FIXME: links routinely go down;
// this shouldn't necessarily exit.
bb_error_msg("iface %s is down", eth_get_name());
if (ready) {
run(argv, "deconfig", &ip);
}
return EXIT_FAILURE;
}
continue;
}
*/
debug_cond(DEBUG_INT_STATE, "%s recv arp type=%d, op=%d,\n",
eth_get_name(), ntohs(arp->ar_pro),
ntohs(arp->ar_op));
debug_cond(DEBUG_INT_STATE, "\tsource=%pM %pI4\n",
&arp->ar_sha,
&arp->ar_spa);
debug_cond(DEBUG_INT_STATE, "\ttarget=%pM %pI4\n",
&arp->ar_tha,
&arp->ar_tpa);
if (arp->ar_op != htons(ARPOP_REQUEST)
&& arp->ar_op != htons(ARPOP_REPLY)
) {
configure_wait();
return;
}
source_ip_conflict = 0;
target_ip_conflict = 0;
if (memcmp(&arp->ar_spa, &ip, ARP_PLEN) == 0
&& memcmp(&arp->ar_sha, NetOurEther, ARP_HLEN) != 0
) {
source_ip_conflict = 1;
}
if (arp->ar_op == htons(ARPOP_REQUEST)
&& memcmp(&arp->ar_tpa, &ip, ARP_PLEN) == 0
&& memcmp(&arp->ar_tha, NetOurEther, ARP_HLEN) != 0
) {
target_ip_conflict = 1;
}
debug_cond(DEBUG_NET_PKT,
"state = %d, source ip conflict = %d, target ip conflict = "
"%d\n", state, source_ip_conflict, target_ip_conflict);
switch (state) {
case PROBE:
case ANNOUNCE:
/* When probing or announcing, check for source IP conflicts
and other hosts doing ARP probes (target IP conflicts). */
if (source_ip_conflict || target_ip_conflict) {
conflicts++;
state = PROBE;
if (conflicts >= MAX_CONFLICTS) {
debug("%s ratelimit\n", eth_get_name());
timeout_ms = RATE_LIMIT_INTERVAL * 1000;
state = RATE_LIMIT_PROBE;
}
/* restart the whole protocol */
ip = pick();
timeout_ms = 0;
nprobes = 0;
nclaims = 0;
}
break;
case MONITOR:
/* If a conflict, we try to defend with a single ARP probe */
if (source_ip_conflict) {
debug("monitor conflict -- defending\n");
state = DEFEND;
timeout_ms = DEFEND_INTERVAL * 1000;
arp_raw_request(ip, NetOurEther, ip);
}
break;
case DEFEND:
/* Well, we tried. Start over (on conflict) */
if (source_ip_conflict) {
state = PROBE;
debug("defend conflict -- starting over\n");
ready = 0;
NetOurIP = 0;
/* restart the whole protocol */
ip = pick();
timeout_ms = 0;
nprobes = 0;
nclaims = 0;
}
break;
default:
/* Invalid, should never happen. Restart the whole protocol */
debug("invalid state -- starting over\n");
state = PROBE;
ip = pick();
timeout_ms = 0;
nprobes = 0;
nclaims = 0;
break;
}
configure_wait();
}
static void link_local_timeout(void)
{
switch (state) {
case PROBE:
/* timeouts in the PROBE state mean no conflicting ARP packets
have been received, so we can progress through the states */
if (nprobes < PROBE_NUM) {
nprobes++;
debug_cond(DEBUG_LL_STATE, "probe/%u %s@%pI4\n",
nprobes, eth_get_name(), &ip);
arp_raw_request(0, NetEtherNullAddr, ip);
timeout_ms = PROBE_MIN * 1000;
timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN);
} else {
/* Switch to announce state */
state = ANNOUNCE;
nclaims = 0;
debug_cond(DEBUG_LL_STATE, "announce/%u %s@%pI4\n",
nclaims, eth_get_name(), &ip);
arp_raw_request(ip, NetOurEther, ip);
timeout_ms = ANNOUNCE_INTERVAL * 1000;
}
break;
case RATE_LIMIT_PROBE:
/* timeouts in the RATE_LIMIT_PROBE state mean no conflicting
ARP packets have been received, so we can move immediately
to the announce state */
state = ANNOUNCE;
nclaims = 0;
debug_cond(DEBUG_LL_STATE, "announce/%u %s@%pI4\n",
nclaims, eth_get_name(), &ip);
arp_raw_request(ip, NetOurEther, ip);
timeout_ms = ANNOUNCE_INTERVAL * 1000;
break;
case ANNOUNCE:
/* timeouts in the ANNOUNCE state mean no conflicting ARP
packets have been received, so we can progress through
the states */
if (nclaims < ANNOUNCE_NUM) {
nclaims++;
debug_cond(DEBUG_LL_STATE, "announce/%u %s@%pI4\n",
nclaims, eth_get_name(), &ip);
arp_raw_request(ip, NetOurEther, ip);
timeout_ms = ANNOUNCE_INTERVAL * 1000;
} else {
/* Switch to monitor state */
state = MONITOR;
printf("Successfully assigned %pI4\n", &ip);
NetCopyIP(&NetOurIP, &ip);
ready = 1;
conflicts = 0;
timeout_ms = -1;
/* Never timeout in the monitor state */
NetSetTimeout(0, NULL);
/* NOTE: all other exit paths should deconfig ... */
net_set_state(NETLOOP_SUCCESS);
return;
}
break;
case DEFEND:
/* We won! No ARP replies, so just go back to monitor */
state = MONITOR;
timeout_ms = -1;
conflicts = 0;
break;
default:
/* Invalid, should never happen. Restart the whole protocol */
state = PROBE;
ip = pick();
timeout_ms = 0;
nprobes = 0;
nclaims = 0;
break;
}
configure_wait();
}
