Support muliple RAs on single interface

IETF is moving toward implementing IPv6 multihoming by sending
multiple RAs on a single interface:
- draft-ietf-intarea-provisioning-domains-00
- draft-ietf-rtgwg-enterprise-pa-multihoming-02

odhcpd supports configuration of multiple software interfaces
on the same physical interface, which already advertises
multiple RAs, but had two issues:
- Each RA includes all the prefixes available on the interface.
- Replies to sollicits with a single RA.

This patch introduces the prefix_filter configuration parameter
which allows filtering prefixes that are sent in a given RA,
and fixes the sollicit code in order to reply with all the RAs
that are configured on a given interface.

Signed-off-by: Pierre Pfister <ppfister@cisco.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/src/config.c b/src/config.c
index bb885d0..409b3b8 100644
--- a/src/config.c
+++ b/src/config.c
@@ -62,6 +62,7 @@ enum {
 	IFACE_ATTR_PD_CER,
 	IFACE_ATTR_NDPROXY_ROUTING,
 	IFACE_ATTR_NDPROXY_SLAVE,
+	IFACE_ATTR_PREFIX_FILTER,
 	IFACE_ATTR_MAX
 };
 
@@ -104,6 +105,7 @@ static const struct blobmsg_policy iface_attrs[IFACE_ATTR_MAX] = {
 	[IFACE_ATTR_RA_MTU] = { .name = "ra_mtu", .type = BLOBMSG_TYPE_INT32 },
 	[IFACE_ATTR_NDPROXY_ROUTING] = { .name = "ndproxy_routing", .type = BLOBMSG_TYPE_BOOL },
 	[IFACE_ATTR_NDPROXY_SLAVE] = { .name = "ndproxy_slave", .type = BLOBMSG_TYPE_BOOL },
+	[IFACE_ATTR_PREFIX_FILTER] = { .name = "prefix_filter", .type = BLOBMSG_TYPE_STRING },
 };
 
 static const struct uci_blob_param_info iface_attr_info[IFACE_ATTR_MAX] = {
@@ -720,6 +722,23 @@ int config_parse_interface(void *data, size_t len, const char *name, bool overwr
 	if ((c = tb[IFACE_ATTR_NDPROXY_SLAVE]))
 		iface->external = blobmsg_get_bool(c);
 
+	if ((c = tb[IFACE_ATTR_PREFIX_FILTER])) {
+		const char *str = blobmsg_get_string(c);
+		char *astr = malloc(strlen(str) + 1);
+		char *delim;
+		int l;
+		if (!astr || !strcpy(astr, str) ||
+				(delim = strchr(astr, '/')) == NULL || (*(delim++) = 0) ||
+				sscanf(delim, "%i", &l) == 0 || l > 128 ||
+				inet_pton(AF_INET6, astr, &iface->pio_filter_addr) == 0) {
+			iface->pio_filter_length = 0;
+		} else {
+			iface->pio_filter_length = l;
+		}
+		if (astr)
+			free(astr);
+	}
+
 	return 0;
 
 err: