From: Roy Marples <roy@marples.name>
Date: Wed, 26 Nov 2014 03:35:09 +0000 (+0000)
Subject: If the IP address is still on the interface when reading a lease,
X-Git-Tag: v6.6.3~5
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e604c2d788293d6abf158b7483f80d1e7af47685;p=thirdparty%2Fdhcpcd.git

If the IP address is still on the interface when reading a lease,
fake add the routes so the lease can be cleaned up if needed.
---

diff --git a/dhcp.c b/dhcp.c
index ea7c0e1a..95b56a89 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -2182,6 +2182,7 @@ dhcp_drop(struct interface *ifp, const char *reason)
 		dhcp_auth_reset(&state->auth);
 		dhcp_close(ifp);
 	}
+
 	if (ifp->options->options & DHCPCD_RELEASE) {
 		unlink(state->leasefile);
 		if (ifp->carrier != LINK_DOWN &&
@@ -2200,6 +2201,7 @@ dhcp_drop(struct interface *ifp, const char *reason)
 #endif
 		}
 	}
+
 	free(state->old);
 	state->old = state->new;
 	state->new = NULL;
@@ -3126,6 +3128,23 @@ dhcp_start1(void *arg)
 	if (state->offer) {
 		get_lease(ifp->ctx, &state->lease, state->offer);
 		state->lease.frominfo = 1;
+		if (state->new == NULL &&
+		    ipv4_iffindaddr(ifp, &state->lease.addr, &state->lease.net))
+		{
+			/* We still have the IP address from the last lease.
+			 * Fake add the address and routes from it so the lease
+			 * can be cleaned up. */
+			state->new = malloc(sizeof(*state->new));
+			if (state->new) {
+				memcpy(state->new, state->offer,
+				    sizeof(*state->new));
+				state->addr = state->lease.addr;
+				state->net = state->lease.net;
+				state->added |= STATE_ADDED | STATE_FAKE;
+				ipv4_buildroutes(ifp->ctx);
+			} else
+				syslog(LOG_ERR, "%s: %m", __func__);
+		}
 		if (state->offer->cookie == 0) {
 			if (state->offer->yiaddr == state->addr.s_addr) {
 				free(state->offer);
@@ -3145,6 +3164,8 @@ dhcp_start1(void *arg)
 				free(state->offer);
 				state->offer = NULL;
 				state->lease.addr.s_addr = 0;
+				if (state->new)
+					dhcp_drop(ifp, "EXPIRE");
 			} else {
 				l = (uint32_t)(now.tv_sec - st.st_mtime);
 				state->lease.leasetime -= l;
diff --git a/ipv4.c b/ipv4.c
index ddb1c973..23ddb502 100644
--- a/ipv4.c
+++ b/ipv4.c
@@ -590,7 +590,7 @@ ipv4_buildroutes(struct dhcpcd_ctx *ctx)
 	struct rt_head *nrs, *dnr;
 	struct rt *or, *rt, *rtn;
 	struct interface *ifp;
-	const struct dhcp_state *state;
+	const struct dhcp_state *state, *ostate;
 
 	nrs = malloc(sizeof(*nrs));
 	if (nrs == NULL) {
@@ -623,6 +623,11 @@ ipv4_buildroutes(struct dhcpcd_ctx *ctx)
 			rt->src.s_addr = state->addr.s_addr;
 			/* Do we already manage it? */
 			if ((or = find_route(ctx->ipv4_routes, rt, NULL))) {
+				if (state->added & STATE_FAKE)
+					continue;
+				ostate = D_CSTATE(or->iface);
+				if (ostate->added & STATE_FAKE)
+					goto remroute;
 				if (or->iface != ifp ||
 				    or->src.s_addr != state->addr.s_addr ||
 				    rt->gate.s_addr != or->gate.s_addr ||
@@ -631,10 +636,12 @@ ipv4_buildroutes(struct dhcpcd_ctx *ctx)
 					if (c_route(or, rt) != 0)
 						continue;
 				}
+remroute:
 				TAILQ_REMOVE(ctx->ipv4_routes, or, next);
 				free(or);
 			} else {
-				if (n_route(rt) != 0)
+				if (!(state->added & STATE_FAKE) &&
+				    n_route(rt) != 0)
 					continue;
 			}
 			TAILQ_REMOVE(dnr, rt, next);
@@ -786,7 +793,8 @@ ipv4_applyaddr(void *arg)
 						} else {
 							ipv4_addaddr(ifn,
 							    &nstate->lease);
-							nstate->added = 1;
+							nstate->added =
+							    STATE_ADDED;
 						}
 						break;
 					}
@@ -863,7 +871,7 @@ ipv4_applyaddr(void *arg)
 	    state->addr.s_addr != 0)
 		delete_address(ifp);
 
-	state->added = 1;
+	state->added = STATE_ADDED;
 	state->defend = 0;
 	state->addr.s_addr = lease->addr.s_addr;
 	state->net.s_addr = lease->net.s_addr;
diff --git a/ipv4.h b/ipv4.h
index 5dbfc9cd..97294ce4 100644
--- a/ipv4.h
+++ b/ipv4.h
@@ -66,6 +66,9 @@ int inet_cidrtoaddr(int, struct in_addr *);
 uint32_t ipv4_getnetmask(uint32_t);
 int ipv4_addrexists(struct dhcpcd_ctx *, const struct in_addr *);
 
+#define STATE_ADDED		0x01
+#define STATE_FAKE		0x02
+
 void ipv4_buildroutes(struct dhcpcd_ctx *);
 void ipv4_applyaddr(void *);
 int ipv4_routedeleted(struct dhcpcd_ctx *, const struct rt *);