Add exit-hook reasons for missing server responses

hooks/dhcpcd-run-hooks.8.in

@@ -124,6 +124,30 @@ dhcpcd's lease or state expired and it failed to obtain a new one.
 .It Dv NAK
 dhcpcd received a NAK from the DHCP server.
 This should be treated as EXPIRE.
+.It Dv DISC_NO_OFFER
+dhcpcd retransmitted a DHCP DISCOVER because no OFFER was received.
+This is a notification only and does not configure or deconfigure.
+.It Dv SOLICIT_NO_ADVERT
+dhcpcd retransmitted a DHCPv6 Solicit because no Advertise was received.
+This is a notification only and does not configure or deconfigure.
+.It Dv REQ_NO_RESP
+dhcpcd failed to receive a response to a DHCP REQUEST and is falling back
+to DISCOVER.
+This is a notification only and does not configure or deconfigure.
+.It Dv REQ6_NO_REPLY
+dhcpcd failed to receive a Reply to a DHCPv6 Request and is falling back
+to Solicit.
+This is a notification only and does not configure or deconfigure.
+.It Dv RENEW_NO_RESP
+dhcpcd failed to renew its DHCPv4 lease at T2 and is entering REBIND.
+This is a notification only and does not configure or deconfigure.
+.It Dv RENEW6_NO_RESP
+dhcpcd failed to renew its DHCPv6 lease at T2 and is entering REBIND.
+This is a notification only and does not configure or deconfigure.
+.It Dv RS_TIMEOUT_NO_RA
+dhcpcd sent the maximum number of Router Solicitations without receiving
+a Router Advertisement.
+This is a notification only and does not configure or deconfigure.
 .It Dv RECONFIGURE
 dhcpcd has been instructed to reconfigure an interface.
 .It Dv ROUTERADVERT

src/dhcp.c

@@ -1944,7 +1944,15 @@ send_inform(void *arg)
 static void
 send_discover(void *arg)
 {
-	send_message((struct interface *)arg, DHCP_DISCOVER, send_discover);
+	struct interface *ifp = arg;
+	struct dhcp_state *state = D_STATE(ifp);
+	/* First call: interval==0 (set to 4 inside send_message).
+	 * Retransmits: interval already 4/8/... - mirror ISC's dhclient. */
+	int retransmit = state->interval != 0;
+
+	send_message(ifp, DHCP_DISCOVER, send_discover);
+	if (retransmit)
+		script_runreason(ifp, "DISC_NO_OFFER");
 }
 
 static void
@@ -2005,6 +2013,7 @@ dhcp_requestfailed(void *arg)
 	state->offer = NULL;
 	state->offer_len = 0;
 	state->interval = 0;
+	script_runreason(ifp, "REQ_NO_RESP");
 	dhcp_discover(ifp);
 }
 
@@ -2096,6 +2105,7 @@ dhcp_rebind(void *arg)
 	struct dhcp_lease *lease = &state->lease;
 
 	logwarnx("%s: failed to renew DHCP, rebinding", ifp->name);
+	script_runreason(ifp, "RENEW_NO_RESP");
 	logdebugx("%s: expire in %" PRIu32 " seconds", ifp->name,
 	    lease->leasetime - lease->rebindtime);
 	state->state = DHS_REBIND;

src/dhcp6.c

@@ -1481,7 +1481,10 @@ dhcp6_sendinform(void *arg)
 static void
 dhcp6_senddiscover2(void *arg)
 {
-	dhcp6_sendmessage(arg, dhcp6_senddiscover2);
+	struct interface *ifp = arg;
+
+	dhcp6_sendmessage(ifp, dhcp6_senddiscover2);
+	script_runreason(ifp, "SOLICIT_NO_ADVERT");
 }
 
 static void
@@ -1495,9 +1498,10 @@ dhcp6_senddiscover1(void *arg)
 	struct interface *ifp = arg;
 	struct dhcp6_state *state = D6_STATE(ifp);
 
-	if (state->recv == NULL || state->recv->type != DHCP6_ADVERTISE)
-		dhcp6_sendmessage(arg, dhcp6_senddiscover2);
-	else
+	if (state->recv == NULL || state->recv->type != DHCP6_ADVERTISE) {
+		dhcp6_sendmessage(ifp, dhcp6_senddiscover2);
+		script_runreason(ifp, "SOLICIT_NO_ADVERT");
+	} else
 		dhcp6_startrequest(ifp);
 }
 
@@ -1863,6 +1867,7 @@ dhcp6_failrequest(void *arg)
 	int llevel = dhcp6_failloglevel(ifp);
 
 	logmessage(llevel, "%s: failed to request DHCPv6 address", ifp->name);
+	script_runreason(ifp, "REQ6_NO_REPLY");
 	dhcp6_fail(ifp, true);
 }
 
@@ -1927,9 +1932,10 @@ dhcp6_startrebind(void *arg)
 	state->RTC = 0;
 	state->MRC = 0;
 
-	if (state->state == DH6S_RENEW)
+	if (state->state == DH6S_RENEW) {
 		logwarnx("%s: failed to renew DHCPv6, rebinding", ifp->name);
-	else {
+		script_runreason(ifp, "RENEW6_NO_RESP");
+	} else {
 		loginfox("%s: rebinding prior DHCPv6 lease", ifp->name);
 
 #ifndef SMALL

src/ipv6nd.c

@@ -434,8 +434,10 @@ ipv6nd_sendrsprobe(void *arg)
 	if (state->rsprobes++ < MAX_RTR_SOLICITATIONS)
 		eloop_timeout_add_sec(ifp->ctx->eloop,
 		    RTR_SOLICITATION_INTERVAL, ipv6nd_sendrsprobe, ifp);
-	else
+	else {
 		logwarnx("%s: no IPv6 Routers available", ifp->name);
+		script_runreason(ifp, "RS_TIMEOUT_NO_RA");
+	}
 }
 
 static void

src/script.c

@@ -325,7 +325,21 @@ make_env(struct dhcpcd_ctx *ctx, const struct interface *ifp,
 			protocol = PROTO_DHCP;
 #endif
 	}
+#ifdef INET
+	else if (strcmp(reason, "DISC_NO_OFFER") == 0 ||
+	    strcmp(reason, "REQ_NO_RESP") == 0 ||
+	    strcmp(reason, "RENEW_NO_RESP") == 0)
+		protocol = PROTO_DHCP;
+#endif
 #ifdef INET6
+#ifdef DHCP6
+	else if (strcmp(reason, "SOLICIT_NO_ADVERT") == 0 ||
+	    strcmp(reason, "REQ6_NO_REPLY") == 0 ||
+	    strcmp(reason, "RENEW6_NO_RESP") == 0)
+		protocol = PROTO_DHCP6;
+#endif
+	else if (strcmp(reason, "RS_TIMEOUT_NO_RA") == 0)
+		protocol = PROTO_RA;
 	else if (strcmp(reason, "STATIC6") == 0)
 		protocol = PROTO_STATIC6;
 #ifdef DHCP6
@@ -440,7 +454,14 @@ make_env(struct dhcpcd_ctx *ctx, const struct interface *ifp,
 		if_down = ifo->options & DHCPCD_RELEASE ? true_str : false_str;
 	} else if (strcmp(reason, "TEST") == 0 ||
 	    strcmp(reason, "PREINIT") == 0 || strcmp(reason, "CARRIER") == 0 ||
-	    strcmp(reason, "STOP") == 0 || strcmp(reason, "UNKNOWN") == 0) {
+	    strcmp(reason, "STOP") == 0 || strcmp(reason, "UNKNOWN") == 0 ||
+	    strcmp(reason, "DISC_NO_OFFER") == 0 ||
+	    strcmp(reason, "REQ_NO_RESP") == 0 ||
+	    strcmp(reason, "RENEW_NO_RESP") == 0 ||
+	    strcmp(reason, "SOLICIT_NO_ADVERT") == 0 ||
+	    strcmp(reason, "REQ6_NO_REPLY") == 0 ||
+	    strcmp(reason, "RENEW6_NO_RESP") == 0 ||
+	    strcmp(reason, "RS_TIMEOUT_NO_RA") == 0) {
 		if_up = false_str;
 		if_down = false_str;
 	} else if (strcmp(reason, "NOCARRIER") == 0) {