From fd3e3bbc461fcbbaefff9339da2e9b6c85a5b4a1 Mon Sep 17 00:00:00 2001
From: Steven Barth <steven@midlink.org>
Date: Tue, 7 Jul 2015 16:01:13 +0200
Subject: [PATCH] router: also send RAs to every known neighbor

---
 src/ndp.c    |  2 +-
 src/odhcpd.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/odhcpd.h |  4 ++++
 src/router.c | 17 +++++++++++++++-
 4 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/src/ndp.c b/src/ndp.c
index 027e9ab..a6f8427 100644
--- a/src/ndp.c
+++ b/src/ndp.c
@@ -356,7 +356,7 @@ static void handle_rtnetlink(_unused void *addr, void *data, size_t len,
 
 		// Data to retrieve
 		size_t rta_offset = (is_route) ? sizeof(*rtm) : (is_addr) ?
-				sizeof(*ifa) : sizeof(*ndm);
+				sizeof(struct ifaddrmsg) : sizeof(*ndm);
 		uint16_t atype = (is_route) ? RTA_DST : (is_addr) ? IFA_ADDRESS : NDA_DST;
 		ssize_t alen = NLMSG_PAYLOAD(nh, rta_offset);
 		struct in6_addr *addr = NULL;
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)
diff --git a/src/odhcpd.h b/src/odhcpd.h
index 5944661..dcd2d14 100644
--- a/src/odhcpd.h
+++ b/src/odhcpd.h
@@ -202,6 +202,10 @@ void odhcpd_hexlify(char *dst, const uint8_t *src, size_t len);
 int odhcpd_bmemcmp(const void *av, const void *bv, size_t bits);
 void odhcpd_bmemcpy(void *av, const void *bv, size_t bits);
 
+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);
+
 int config_parse_interface(void *data, size_t len, const char *iname, bool overwrite);
 
 #ifdef WITH_UBUS
diff --git a/src/router.c b/src/router.c
index f942d8f..718f170 100644
--- a/src/router.c
+++ b/src/router.c
@@ -37,6 +37,7 @@ static void sigusr1_refresh(int signal);
 static struct odhcpd_event router_event = {{.fd = -1}, handle_icmpv6};
 
 static FILE *fp_route = NULL;
+#define RA_IOV_LEN 6
 
 
 int init_router(void)
@@ -205,6 +206,18 @@ static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len)
 	return found_default;
 }
 
+// Unicsat RAs
+static void send_neigh_ra(const struct in6_addr *addr,
+		const struct interface *iface, void *data)
+{
+	struct sockaddr_in6 dest = {
+		.sin6_family = AF_INET6,
+		.sin6_addr = *addr,
+		.sin6_scope_id = iface->ifindex,
+	};
+	odhcpd_send(router_event.uloop.fd, &dest, data, RA_IOV_LEN, iface);
+}
+
 
 // Router Advert server mode
 static uint64_t send_router_advert(struct interface *iface, const struct in6_addr *from)
@@ -443,7 +456,8 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
 		.data = {0, 0, maxival >> 24, maxival >> 16, maxival >> 8, maxival}
 	};
 
-	struct iovec iov[] = {{&adv, (uint8_t*)&adv.prefix[cnt] - (uint8_t*)&adv},
+	struct iovec iov[RA_IOV_LEN] = {
+			{&adv, (uint8_t*)&adv.prefix[cnt] - (uint8_t*)&adv},
 			{&routes, routes_cnt * sizeof(*routes)},
 			{&dns, (dns_cnt) ? sizeof(dns) : 0},
 			{dns_addr, dns_cnt * sizeof(*dns_addr)},
@@ -457,6 +471,7 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
 	odhcpd_send(router_event.uloop.fd,
 			&dest, iov, ARRAY_SIZE(iov), iface);
 
+	odhcpd_iterate_interface_neighbors(iface, send_neigh_ra, iov);
 	return msecs;
 }
 
-- 
2.25.1