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, 9 deletions

diff --git a/src/odhcpd.c b/src/odhcpd.c
index 97a6de9..58c4338 100644
--- a/src/odhcpd.c
+++ b/src/odhcpd.c
@@ -371,12 +371,6 @@ static void odhcpd_receive_packets(struct uloop_fd *u, _unused unsigned int even
 		if (addr.ll.sll_family == AF_PACKET)
 			destiface = addr.ll.sll_ifindex;
 
-		struct interface *iface =
-				odhcpd_get_interface_by_index(destiface);
-
-		if (!iface && addr.nl.nl_family != AF_NETLINK)
-			continue;
-
 		char ipbuf[INET6_ADDRSTRLEN] = "kernel";
 		if (addr.ll.sll_family == AF_PACKET &&
 				len >= (ssize_t)sizeof(struct ip6_hdr))
@@ -386,10 +380,26 @@ static void odhcpd_receive_packets(struct uloop_fd *u, _unused unsigned int even
 		else if (addr.in.sin_family == AF_INET)
 			inet_ntop(AF_INET, &addr.in.sin_addr, ipbuf, sizeof(ipbuf));
 
-		syslog(LOG_DEBUG, "Received %li Bytes from %s%%%s", (long)len,
-				ipbuf, (iface) ? iface->ifname : "netlink");
+		// From netlink
+		if (addr.nl.nl_family == AF_NETLINK) {
+			syslog(LOG_DEBUG, "Received %li Bytes from %s%%%s", (long)len,
+					ipbuf, "netlink");
+			e->handle_dgram(&addr, data_buf, len, NULL, dest);
+			return;
+		} else if (destiface != 0) {
+			struct interface *iface;
+			list_for_each_entry(iface, &interfaces, head) {
+				if (iface->ifindex != destiface)
+					continue;
+
+				syslog(LOG_DEBUG, "Received %li Bytes from %s%%%s", (long)len,
+						ipbuf, iface->ifname);
+
+				e->handle_dgram(&addr, data_buf, len, iface, dest);
+			}
+		}
+
 
-		e->handle_dgram(&addr, data_buf, len, iface, dest);
 	}
 }