From: Roy Marples <roy@marples.name>
Date: Fri, 24 Jul 2015 20:47:08 +0000 (+0000)
Subject: When dropping IPv4LL state, remove the address and rebuild routes before
X-Git-Tag: v6.9.2~27
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1b34ac49dde0d43a4c059107676209ccc922cd17;p=thirdparty%2Fdhcpcd.git

When dropping IPv4LL state, remove the address and rebuild routes before
calling dhcpcd-run-hooks.
Ensure that the IPv4LL random state is only used when picking addresses
and the original state is restored.
---

diff --git a/dhcpcd.h b/dhcpcd.h
index 31b6959e..5c5fc18a 100644
--- a/dhcpcd.h
+++ b/dhcpcd.h
@@ -123,6 +123,8 @@ struct dhcpcd_ctx {
 	struct dhcp_opt *vivso;
 	size_t vivso_len;
 
+	char *randomstate; /* original state */
+
 #ifdef INET
 	struct dhcp_opt *dhcp_opts;
 	size_t dhcp_opts_len;
diff --git a/ipv4ll.c b/ipv4ll.c
index c119778f..564f98f4 100644
--- a/ipv4ll.c
+++ b/ipv4ll.c
@@ -52,6 +52,10 @@ static in_addr_t
 ipv4ll_pick_addr(const struct arp_state *astate)
 {
 	struct in_addr addr;
+	struct ipv4ll_state *istate;
+
+	istate = IPV4LL_STATE(astate->iface);
+	setstate(istate->randomstate);
 
 	do {
 		/* RFC 3927 Section 2.1 states that the first 256 and
@@ -66,6 +70,9 @@ ipv4ll_pick_addr(const struct arp_state *astate)
 		/* Ensure we don't have the address on another interface */
 	} while (ipv4_findaddr(astate->iface->ctx, &addr) != NULL);
 
+	/* Restore the original random state */
+	setstate(astate->iface->ctx->randomstate);
+
 	return addr.s_addr;
 }
 
@@ -315,6 +322,7 @@ ipv4ll_start(void *arg)
 	 * the same address without persistent storage. */
 	if (state->conflicts == 0) {
 		unsigned int seed;
+		char *orig;
 
 		if (sizeof(seed) > ifp->hwlen) {
 			seed = 0;
@@ -322,7 +330,15 @@ ipv4ll_start(void *arg)
 		} else
 			memcpy(&seed, ifp->hwaddr + ifp->hwlen - sizeof(seed),
 			    sizeof(seed));
-		initstate(seed, state->randomstate, sizeof(state->randomstate));
+		orig = initstate(seed,
+		    state->randomstate, sizeof(state->randomstate));
+
+		/* Save the original state. */
+		if (ifp->ctx->randomstate == NULL)
+			ifp->ctx->randomstate = orig;
+
+		/* Set back the original state until we need the seeded one. */
+		setstate(ifp->ctx->randomstate);
 	}
 
 	if ((astate = arp_new(ifp, NULL)) == NULL)
@@ -358,7 +374,6 @@ ipv4ll_start(void *arg)
 		return;
 	}
 
-	setstate(state->randomstate);
 	logger(ifp->ctx, LOG_INFO, "%s: probing for an IPv4LL address",
 	    ifp->name);
 	astate->addr.s_addr = ipv4ll_pick_addr(astate);
@@ -407,16 +422,15 @@ ipv4ll_freedrop(struct interface *ifp, int drop)
 				}
 			}
 		}
-
-		if (dropped)
-			script_runreason(ifp, "IPV4LL");
 	}
 
 	if (state) {
 		free(state);
 		ifp->if_data[IF_DATA_IPV4LL] = NULL;
 
-		if (dropped)
+		if (dropped) {
 			ipv4_buildroutes(ifp->ctx);
+			script_runreason(ifp, "IPV4LL");
+		}
 	}
 }