DHCP6: release cleanly

While here address some hangup issues.

Author: rsmarples

src/dhcp6.c

@@ -2110,12 +2110,10 @@ dhcp6_startrelease(struct interface *ifp)
 	struct dhcp6_state *state;
 
 	state = D6_STATE(ifp);
-	if (state->state != DH6S_BOUND)
+	if (state->state != DH6S_BOUND) {
+		dhcp6_finishrelease(ifp);
 		return;
-
-	/* RFC8415 18.2.7 says we must stop using the addresses before
-	 * we send the release message. */
-	dhcp6_freedrop_addrs(ifp, 0, IPV6_AF_DELEGATED, NULL);
+	}
 
 	state->state = DH6S_RELEASE;
 	state->RTC = 0;

src/dhcpcd.c

@@ -1187,9 +1187,6 @@ dhcpcd_handlelink(void *arg, unsigned short events)
 {
 	struct dhcpcd_ctx *ctx = arg;
 
-	if (ctx->options & DHCPCD_EXITING)
-		return;
-
 	if (events != ELE_READ)
 		logerrx("%s: unexpected event 0x%04x", __func__, events);
 

src/privsep.c

@@ -1136,6 +1136,10 @@ ps_recvpsmsg(struct dhcpcd_ctx *ctx, int fd, unsigned short events,
 	struct msghdr msg = { .msg_iov = iov, .msg_iovlen = 1 };
 	bool stop = false;
 
+	if (events & ELE_HANGUP) {
+		len = 0;
+		goto stop;
+	}
 	if (!(events & ELE_READ))
 		logerrx("%s: unexpected event 0x%04x", __func__, events);
 
@@ -1163,6 +1167,7 @@ ps_recvpsmsg(struct dhcpcd_ctx *ctx, int fd, unsigned short events,
 	}
 
 	if (stop) {
+stop:
 		ctx->options |= DHCPCD_EXITING;
 #ifdef PRIVSEP_DEBUG
 		logdebugx("process %d stopping", getpid());