1 files changed, 55 insertions, 0 deletions
diff --git a/src/odhcpd.c b/src/odhcpd.c
index aad5b37..3fb3009 100644
--- a/src/odhcpd.c
+++ b/src/odhcpd.c
@@ -194,6 +194,61 @@ ssize_t odhcpd_send(int socket, struct sockaddr_in6 *dest,
 }
 
 
+int odhcpd_iterate_interface_neighbors(const struct interface *iface,
+		void(*cb_neigh)(const struct in6_addr *addr,
+				const struct interface *iface, void *data), void *data)
+{
+	struct {
+		struct nlmsghdr nhm;
+		struct ndmsg ndm;
+	} req = {{sizeof(req), RTM_GETNEIGH, NLM_F_REQUEST | NLM_F_DUMP,
+			++rtnl_seq, 0}, {AF_INET6, 0, 0, iface->ifindex, 0, 0, 0}};
+
+	if (send(rtnl_socket, &req, sizeof(req), 0) < (ssize_t)sizeof(req))
+		return -1;
+
+	uint8_t buf[8192];
+	ssize_t len = 0;
+
+	for (struct nlmsghdr *nhm = NULL; ; nhm = NLMSG_NEXT(nhm, len)) {
+		while (len < 0 || !NLMSG_OK(nhm, (size_t)len)) {
+			len = recv(rtnl_socket, buf, sizeof(buf), 0);
+			nhm = (struct nlmsghdr*)buf;
+			if (len < 0 || !NLMSG_OK(nhm, (size_t)len)) {
+				if (errno == EINTR)
+					continue;
+				else
+					return -1;
+			}
+		}
+
+		if (nhm->nlmsg_type != RTM_NEWNEIGH)
+			break;
+
+		struct ndmsg *ndm = NLMSG_DATA(nhm);
+		if (ndm->ndm_ifindex != iface->ifindex ||
+				(ndm->ndm_state & NUD_FAILED))
+			continue;
+
+		struct rtattr *rta = (struct rtattr*)&ndm[1];
+		size_t alen = NLMSG_PAYLOAD(nhm, sizeof(*ndm));
+
+		while (RTA_OK(rta, alen)) {
+			if (rta->rta_type == NDA_DST) {
+				// TODO
+				cb_neigh(NULL, iface, data);
+				break;
+			} else {
+				rta = RTA_NEXT(rta, alen);
+			}
+		}
+
+	}
+
+	return 0;
+}
+
+
 // Detect an IPV6-address currently assigned to the given interface
 ssize_t odhcpd_get_interface_addresses(int ifindex,
 		struct odhcpd_ipaddr *addrs, size_t cnt)