RFC2131 implies that we should only ARP check after an offer.

diff --git a/arp.c b/arp.c
index bc1d8b1451502fca43cb6823e0ddc5dd379b3047..17a3d9ad3a97600d11ce8893d1e39b70b77ae2ac 100644 (file)
--- a/arp.c
+++ b/arp.c
@@ -242,13 +242,7 @@ send_arp_probe(void *arg)
        } else {
                tv.tv_sec = ANNOUNCE_WAIT;
                tv.tv_usec = 0;
-               /* We will bind IPv4LL and BOOTP addresses */
-               if ((state->lease.server.s_addr == 0 &&
-                    state->lease.frominfo == 0) ||
-                   IN_LINKLOCAL(htonl(addr.s_addr)))
-                       add_timeout_tv(&tv, bind_interface, iface);
-               else
-                       add_timeout_tv(&tv, start_request, iface);
+               add_timeout_tv(&tv, bind_interface, iface);
        }
        syslog(LOG_DEBUG,
               "%s: sending ARP probe (%d of %d), next in %0.2f seconds",

diff --git a/dhcpcd.c b/dhcpcd.c
index 9c7244f06c36fd910f7429d8346088d1f580a37e..acf30b183762cfc7eb1ed668d782b3beeb11f670 100644 (file)
--- a/dhcpcd.c
+++ b/dhcpcd.c
@@ -503,23 +503,14 @@ handle_dhcp(struct interface *iface, struct dhcp_message **dhcpp)
                        exit(EXIT_SUCCESS);
                }
                delete_timeout(send_discover, iface);
-               if (ifo->options & DHCPCD_ARP &&
-                   iface->addr.s_addr != state->offer->yiaddr)
-               {
-                       /* If the interface already has the address configured
-                        * then we can't ARP for duplicate detection. */
-                       addr.s_addr = state->offer->yiaddr;
-                       if (!has_address(iface->name, &addr, NULL)) {
-                               state->claims = 0;
-                               state->probes = 0;
-                               state->conflicts = 0;
-                               state->state = DHS_PROBE;
-                               send_arp_probe(iface);
-                               return;
-                       }
-               }
                /* We don't request BOOTP addresses */
                if (type) {
+                       /* We used to ARP check here, but that seems to be in
+                        * violation of RFC2131 where it only describes
+                        * DECLINE after REQUEST.
+                        * It also seems that some MS DHCP servers actually
+                        * ignore DECLINE if no REQUEST, ie we decline a
+                        * DISCOVER. */
                        start_request(iface);
                        return;
                }
@@ -541,7 +532,6 @@ handle_dhcp(struct interface *iface, struct dhcp_message **dhcpp)
                        log_dhcp(LOG_INFO, "acknowledged", iface, dhcp);
        }
 
-       close_sockets(iface);
        /* BOOTP could have already assigned this above, so check we still
         * have a pointer. */
        if (*dhcpp) {
@@ -549,9 +539,26 @@ handle_dhcp(struct interface *iface, struct dhcp_message **dhcpp)
                state->offer = dhcp;
                *dhcpp = NULL;
        }
-       /* Delete all timeouts for this interface. */
-       delete_timeout(NULL, iface);
        lease->frominfo = 0;
+
+       delete_timeout(NULL, iface);
+       if (ifo->options & DHCPCD_ARP &&
+           iface->addr.s_addr != state->offer->yiaddr)
+       {
+               /* If the interface already has the address configured
+                * then we can't ARP for duplicate detection. */
+               addr.s_addr = state->offer->yiaddr;
+               if (!has_address(iface->name, &addr, NULL)) {
+                       state->claims = 0;
+                       state->probes = 0;
+                       state->conflicts = 0;
+                       state->state = DHS_PROBE;
+                       send_arp_probe(iface);
+                       return;
+               }
+       }
+
+       close_sockets(iface);
        bind_interface(iface);
 }
 
@@ -836,15 +843,10 @@ start_reboot(struct interface *iface)
        else
                add_timeout_sec(ifo->reboot, start_expire, iface);
        open_sockets(iface);
-       if (ifo->options & DHCPCD_ARP &&
-           !has_address(iface->name, &iface->state->lease.addr, NULL))
-       {
-               iface->state->probes = 0;
-               send_arp_probe(iface);
-       } else if (ifo->options & DHCPCD_INFORM)
+       /* Don't bother ARP checking as the server could NAK us first. */
+       if (ifo->options & DHCPCD_INFORM)
                send_inform(iface);
        else
-               /* We don't start_request as that would change state */
                send_request(iface);
 }