From: Roy Marples <roy@marples.name>
Date: Fri, 10 Mar 2017 11:05:02 +0000 (+0000)
Subject: Only conflict on ARP when sip matches OR sip is INADDR_ANY and
X-Git-Tag: v7.0.0-beta1~56
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d5e1d4fd7bb41a5fb9c19b82d757ed6ba9834347;p=thirdparty%2Fdhcpcd.git

Only conflict on ARP when sip matches OR sip is INADDR_ANY and
tip matches and we haven't added the address yet.
---

diff --git a/dhcp.c b/dhcp.c
index 39193b5b..f0ce8d53 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -2095,9 +2095,7 @@ dhcp_arp_conflicted(struct arp_state *astate, const struct arp_msg *amsg)
 	if (state->arping_index != -1 &&
 	    state->arping_index < ifo->arping_len &&
 	    amsg &&
-	    (amsg->sip.s_addr == ifo->arping[state->arping_index] ||
-	    (amsg->sip.s_addr == 0 &&
-	    amsg->tip.s_addr == ifo->arping[state->arping_index])))
+	    amsg->sip.s_addr == ifo->arping[state->arping_index])
 	{
 		char buf[HWADDR_LEN * 3];
 
@@ -2160,9 +2158,7 @@ dhcp_arp_conflicted(struct arp_state *astate, const struct arp_msg *amsg)
 
 	/* Bound address */
 	if (amsg && state->addr &&
-	    (amsg->sip.s_addr == state->addr->addr.s_addr ||
-	    (amsg->sip.s_addr == 0 &&
-	    amsg->tip.s_addr == state->addr->addr.s_addr)))
+	    amsg->sip.s_addr == state->addr->addr.s_addr)
 	{
 		astate->failed = state->addr->addr;
 		arp_report_conflicted(astate, amsg);
diff --git a/ipv4ll.c b/ipv4ll.c
index ce28c817..fd37ac8d 100644
--- a/ipv4ll.c
+++ b/ipv4ll.c
@@ -244,7 +244,6 @@ ipv4ll_conflicted(struct arp_state *astate, const struct arp_msg *amsg)
 {
 	struct interface *ifp;
 	struct ipv4ll_state *state;
-	in_addr_t fail;
 
 	assert(astate != NULL);
 	assert(astate->iface != NULL);
@@ -252,23 +251,19 @@ ipv4ll_conflicted(struct arp_state *astate, const struct arp_msg *amsg)
 	state = IPV4LL_STATE(ifp);
 	assert(state != NULL);
 
-	fail = 0;
-	/* RFC 3927 2.2.1, Probe Conflict Detection */
+	/*
+	 * NULL amsg means kernel detected DAD.
+	 * We always fail on matching sip.
+	 * We only fail on matching tip and we haven't added that address yet.
+	 */
 	if (amsg == NULL ||
-	    (amsg->sip.s_addr == astate->addr.s_addr ||
-	    (amsg->sip.s_addr == 0 && amsg->tip.s_addr == astate->addr.s_addr)))
-		fail = astate->addr.s_addr;
-
-	/* RFC 3927 2.5, Conflict Defense */
-	if (state->addr != NULL &&
-	    IN_LINKLOCAL(ntohl(state->addr->addr.s_addr)) &&
-	    amsg && amsg->sip.s_addr == state->addr->addr.s_addr)
-		fail = state->addr->addr.s_addr;
-
-	if (fail == 0)
+	    amsg->sip.s_addr == astate->addr.s_addr ||
+	    (amsg->sip.s_addr == 0 && amsg->tip.s_addr == astate->addr.s_addr
+	     && ipv4_iffindaddr(ifp, &amsg->tip, NULL) == NULL))
+		astate->failed = astate->addr;
+	else
 		return;
 
-	astate->failed.s_addr = fail;
 	arp_report_conflicted(astate, amsg);
 
 	if (state->addr != NULL &&