From: Hans Dedecker <dedeckeh@gmail.com>
Date: Wed, 2 Aug 2017 20:32:08 +0000 (+0200)
Subject: dhcpv6: assign all viable DHCPv6 addresses by default (FS#402, FS#524)
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=296b4a0ddd7d6d77e48ee36f3407b0769caaa0d7;p=project%2Fodhcpd.git

dhcpv6: assign all viable DHCPv6 addresses by default (FS#402, FS#524)

Some client implementations expect DHCPv6 addresses to be assigned for
every prefix present in a RA as reported in FS#524; if not done the
client implementations spam the DHCPv6 server with SOLICIT messages
trying to get an DHCPv6 address for every prefix.
When ra_managed is set to 1 and an ULA prefix is configured; the DHCPv6
server will only assign an ULA DHCPv6 addresses which possibly leads to
DNS issues.

Fix these problems by providing dhcpv6_assignall config option which
assigns all viable DHCPv6 addresses to a client by default.
This is a trade off as it means client implementations will be assigned
more IPv6 addresses and lose the ability to quickly renumber clients
which don't support reconfigure accept in case of wan prefix change

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
---

diff --git a/README b/README
index fbcd993..f4945ce 100644
--- a/README
+++ b/README
@@ -90,6 +90,10 @@ ndp			string	disabled		Neighbor Discovery Proxy
 
 dynamicdhcp		bool	1			Dynamically create leases
 							for DHCPv4 and DHCPv6
+dhcpv6_assignall	bool	1			Assign all viable DHCPv6 addresses
+							in statefull mode; if disabled
+							only the DHCPv6 address having the
+							longest preferred lifetime is assigned
 router			list    <local address>		Routers to announce
 							accepts IPv4 only
 dns			list	<local address>		DNS servers to announce
diff --git a/src/config.c b/src/config.c
index 8670efc..19b901c 100644
--- a/src/config.c
+++ b/src/config.c
@@ -43,6 +43,7 @@ enum {
 	IFACE_ATTR_DOMAIN,
 	IFACE_ATTR_FILTER_CLASS,
 	IFACE_ATTR_DHCPV6_RAW,
+	IFACE_ATTR_DHCPV6_ASSIGNALL,
 	IFACE_ATTR_RA_DEFAULT,
 	IFACE_ATTR_RA_MANAGEMENT,
 	IFACE_ATTR_RA_OFFLINK,
@@ -83,6 +84,7 @@ static const struct blobmsg_policy iface_attrs[IFACE_ATTR_MAX] = {
 	[IFACE_ATTR_DOMAIN] = { .name = "domain", .type = BLOBMSG_TYPE_ARRAY },
 	[IFACE_ATTR_FILTER_CLASS] = { .name = "filter_class", .type = BLOBMSG_TYPE_STRING },
 	[IFACE_ATTR_DHCPV6_RAW] = { .name = "dhcpv6_raw", .type = BLOBMSG_TYPE_STRING },
+	[IFACE_ATTR_DHCPV6_ASSIGNALL] = { .name ="dhcpv6_assignall", .type = BLOBMSG_TYPE_BOOL },
 	[IFACE_ATTR_PD_MANAGER] = { .name = "pd_manager", .type = BLOBMSG_TYPE_STRING },
 	[IFACE_ATTR_PD_CER] = { .name = "pd_cer", .type = BLOBMSG_TYPE_STRING },
 	[IFACE_ATTR_RA_DEFAULT] = { .name = "ra_default", .type = BLOBMSG_TYPE_INT32 },
@@ -205,9 +207,10 @@ static struct interface* get_interface(const char *name)
 
 static void set_interface_defaults(struct interface *iface)
 {
-	iface->ra_managed = RA_MANAGED_MFLAG;
 	iface->learn_routes = 1;
 	iface->dhcpv4_leasetime = 43200;
+	iface->dhcpv6_assignall = true;
+	iface->ra_managed = RA_MANAGED_MFLAG;
 	iface->ra_maxinterval = 600;
 	iface->ra_mininterval = iface->ra_maxinterval/3;
 	iface->ra_lifetime = -1;
@@ -617,6 +620,9 @@ int config_parse_interface(void *data, size_t len, const char *name, bool overwr
 		odhcpd_unhexlify(iface->dhcpv6_raw, iface->dhcpv6_raw_len, blobmsg_get_string(c));
 	}
 
+	if ((c = tb[IFACE_ATTR_DHCPV6_ASSIGNALL]))
+		iface->dhcpv6_assignall = blobmsg_get_bool(c);
+
 	if ((c = tb[IFACE_ATTR_RA_DEFAULT]))
 		iface->default_router = blobmsg_get_u32(c);
 
diff --git a/src/dhcpv6-ia.c b/src/dhcpv6-ia.c
index 8bf42c8..847ede4 100644
--- a/src/dhcpv6-ia.c
+++ b/src/dhcpv6-ia.c
@@ -36,7 +36,7 @@
 #include <libubox/usock.h>
 
 #define ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs) \
-    ((iface)->ra_managed == RA_MANAGED_NO_AFLAG || (i) == (m) || \
+    ((iface)->dhcpv6_assignall || (i) == (m) || \
      (addrs)[(i)].prefix > 64)
 
 static void free_dhcpv6_assignment(struct dhcpv6_assignment *c);
diff --git a/src/odhcpd.h b/src/odhcpd.h
index 10f0edb..a03baf0 100644
--- a/src/odhcpd.h
+++ b/src/odhcpd.h
@@ -185,8 +185,10 @@ struct interface {
 	uint8_t *search;
 	size_t search_len;
 
+	// DHCPV6
 	void *dhcpv6_raw;
 	size_t dhcpv6_raw_len;
+	bool dhcpv6_assignall;
 
 	char *upstream;
 	size_t upstream_len;