Always send req for InfoRefreshTime option on Inform-Req (#446)

RFC8415 says client must always request Information Request refresh time
option 32.
Client has other logic for handling if server does not include this in
the reply.

Resolves #445.

Author: ColinMcInnes

src/dhcp6.c

@@ -1742,16 +1742,22 @@ static void
 dhcp6_startdiscover(void *arg)
 {
 	struct interface *ifp;
+	struct if_options *ifo;
 	struct dhcp6_state *state;
 	int llevel;
 	struct ipv6_addr *ia;
 
 	ifp = arg;
 	state = D6_STATE(ifp);
+	ifo = ifp->options;
 #ifndef SMALL
 	if (state->reason == NULL || strcmp(state->reason, "TIMEOUT6") != 0)
 		dhcp6_delete_delegates(ifp);
 #endif
+	/* Ensure we never request INFO_REFRESH_TIME,
+ 	 * this only belongs in Information-Request messages */
+	del_option_mask(ifo->requestmask6, D6_OPTION_INFO_REFRESH_TIME);
+
 	if (state->new == NULL && !state->failed)
 		llevel = LOG_INFO;
 	else
@@ -1784,9 +1790,11 @@ dhcp6_startinform(void *arg)
 	struct interface *ifp;
 	struct dhcp6_state *state;
 	int llevel;
+	struct if_options *ifo;
 
 	ifp = arg;
 	state = D6_STATE(ifp);
+	ifo = ifp->options;
 	llevel = state->failed ? LOG_DEBUG : LOG_INFO;
 	logmessage(llevel, "%s: requesting DHCPv6 information", ifp->name);
 	state->state = DH6S_INFORM;
@@ -1796,6 +1804,9 @@ dhcp6_startinform(void *arg)
 	state->MRT = state->inf_max_rt;
 	state->MRC = 0;
 
+	/* Ensure we always request INFO_REFRESH_TIME as per rfc8415 */
+	add_option_mask(ifo->requestmask6, D6_OPTION_INFO_REFRESH_TIME);
+
 	if (dhcp6_makemessage(ifp) == -1) {
 		logerr("%s: %s", __func__, ifp->name);
 		return;
@@ -2815,19 +2826,21 @@ static void
 dhcp6_startinit(struct interface *ifp)
 {
 	struct dhcp6_state *state;
+	struct if_options *ifo;
 	ssize_t r;
 	uint8_t has_ta, has_non_ta;
 	size_t i;
 
 	state = D6_STATE(ifp);
+	ifo = ifp->options;
 	state->state = DH6S_INIT;
 	state->expire = ND6_INFINITE_LIFETIME;
 	state->lowpl = ND6_INFINITE_LIFETIME;
 
 	dhcp6_addrequestedaddrs(ifp);
 	has_ta = has_non_ta = 0;
-	for (i = 0; i < ifp->options->ia_len; i++) {
-		switch (ifp->options->ia[i].ia_type) {
+	for (i = 0; i < ifo->ia_len; i++) {
+		switch (ifo->ia[i].ia_type) {
 		case D6_OPTION_IA_TA:
 			has_ta = 1;
 			break;
@@ -2838,14 +2851,14 @@ dhcp6_startinit(struct interface *ifp)
 
 	if (!(ifp->ctx->options & DHCPCD_TEST) &&
 	    !(has_ta && !has_non_ta) &&
-	    ifp->options->reboot != 0)
+	    ifo->reboot != 0)
 	{
 		r = dhcp6_readlease(ifp, 1);
 		if (r == -1) {
 			if (errno != ENOENT && errno != ESRCH)
 				logerr("%s: %s", __func__, state->leasefile);
 		} else if (r != 0 &&
-		    !(ifp->options->options & DHCPCD_ANONYMOUS))
+		    !(ifo->options & DHCPCD_ANONYMOUS))
 		{
 			/* RFC 3633 section 12.1 */
 #ifndef SMALL
@@ -4059,13 +4072,10 @@ dhcp6_start1(void *arg)
 		del_option_mask(ifo->requestmask6, D6_OPTION_RAPID_COMMIT);
 #endif
 
-	if (state->state == DH6S_INFORM) {
-		add_option_mask(ifo->requestmask6, D6_OPTION_INFO_REFRESH_TIME);
+	if (state->state == DH6S_INFORM)
 		dhcp6_startinform(ifp);
-	} else {
-		del_option_mask(ifo->requestmask6, D6_OPTION_INFO_REFRESH_TIME);
+	else
 		dhcp6_startinit(ifp);
-	}
 
 #ifndef SMALL
 	dhcp6_activateinterfaces(ifp);