Fix dhcpcd sending wrong message when RENEWING/REBINDING

When RENEWING/REBINDING, the DHCP client should send messages with
ciaddr set and requested-ip unset. However when dhcpcd 10 is configured
with --noconfigure, the messages sent are the opposite: ciaddr unset
and requested-ip set - these messages are for INIT-REBOOT, not RENEWING
or REBINDING.

The reason for it is that when --noconfigure is enabled, dhcpcd won't
setup the state->addr property of the interface when the lease is bound.
When dhcpcd renews or rebinds the lease later, it needs state->addr to
be set to correctly configure ciaddr and requested-ip. Since state->addr
is NULL, dhcpcd sends wrong messages (for the detail see
github.com/NetworkConfiguration/issues/355).

This patch fixes this by also setting up state->addr with
ipv4_applyaddr() when --noconfigure is enabled. Note that this function
also configure the IPv4 address and build routes in the system, so we
need to disable these in the function.

Change-Id: I94bfffd95b62066995bd436d3b8bf185eafda398

src/dhcp.c

@@ -2374,24 +2374,6 @@ dhcp_bind(struct interface *ifp)
 
 	old_state = state->added;
 
-	if (!(ifo->options & DHCPCD_CONFIGURE)) {
-		struct ipv4_addr *ia;
-
-		script_runreason(ifp, state->reason);
-		dhcpcd_daemonise(ifp->ctx);
-
-		/* We we are not configuring the address, we need to keep
-		 * the BPF socket open if the address does not exist. */
-		ia = ipv4_iffindaddr(ifp, &state->lease.addr, NULL);
-		if (ia != NULL) {
-			state->addr = ia;
-			state->added = STATE_ADDED;
-			dhcp_closebpf(ifp);
-			goto openudp;
-		}
-		return;
-	}
-
 	/* Add the address */
 	if (ipv4_applyaddr(ifp) == NULL) {
 		/* There was an error adding the address.
@@ -2403,6 +2385,9 @@ dhcp_bind(struct interface *ifp)
 		return;
 	}
 
+	if (!(ifo->options & DHCPCD_CONFIGURE))
+		return;
+
 	/* Close the BPF filter as we can now receive DHCP messages
 	 * on a UDP socket. */
 	dhcp_closebpf(ifp);
@@ -2848,13 +2833,7 @@ dhcp_drop(struct interface *ifp, const char *reason)
 	state->new = NULL;
 	state->new_len = 0;
 	state->reason = reason;
-	if (ifp->options->options & DHCPCD_CONFIGURE)
-		ipv4_applyaddr(ifp);
-	else {
-		state->addr = NULL;
-		state->added = 0;
-		script_runreason(ifp, state->reason);
-	}
+	ipv4_applyaddr(ifp);
 	free(state->old);
 	state->old = NULL;
 	state->old_len = 0;

src/ipv4.c

@@ -527,11 +527,13 @@ ipv4_deladdr(struct ipv4_addr *addr, int keeparp)
 	logdebugx("%s: deleting IP address %s",
 	    addr->iface->name, addr->saddr);
 
-	r = if_address(RTM_DELADDR, addr);
-	if (r == -1 &&
-	    errno != EADDRNOTAVAIL && errno != ESRCH &&
-	    errno != ENXIO && errno != ENODEV)
-		logerr("%s: %s", addr->iface->name, __func__);
+	if (addr->iface->options->options & DHCPCD_CONFIGURE) {
+		r = if_address(RTM_DELADDR, addr);
+		if (r == -1 &&
+			errno != EADDRNOTAVAIL && errno != ESRCH &&
+			errno != ENXIO && errno != ENODEV)
+			logerr("%s: %s", addr->iface->name, __func__);
+	}
 
 #ifdef ARP
 	if (!keeparp)
@@ -721,7 +723,8 @@ ipv4_addaddr(struct interface *ifp, const struct in_addr *addr,
 	    ifp->name, ia->saddr,
 	    ifp->flags & IFF_POINTOPOINT ? "destination" : "broadcast",
 	    inet_ntoa(*bcast));
-	if (if_address(RTM_NEWADDR, ia) == -1) {
+	if (ifp->options->options & DHCPCD_CONFIGURE &&
+		if_address(RTM_NEWADDR, ia) == -1) {
 		if (errno != EEXIST)
 			logerr("%s: if_addaddress",
 			    __func__);

src/route.c

@@ -704,6 +704,10 @@ rt_doroute(rb_tree_t *kroutes, struct rt *rt)
 void
 rt_build(struct dhcpcd_ctx *ctx, int af)
 {
+	if (!(ctx->options & DHCPCD_CONFIGURE)) {
+		return;
+	}
+
 	rb_tree_t routes, added, kroutes;
 	struct rt *rt, *rtn;
 	unsigned long long o;