router: add syslog debug tracing for trouble shooting
[project/odhcpd.git] / src / ndp.c
index e006c85..d2fbe07 100644 (file)
--- a/src/ndp.c
+++ b/src/ndp.c
@@ -17,6 +17,8 @@
 #include <signal.h>
 #include <errno.h>
 
+#include <fcntl.h>
+#include <unistd.h>
 #include <arpa/inet.h>
 #include <sys/socket.h>
 #include <net/ethernet.h>
 #include <linux/rtnetlink.h>
 #include <linux/filter.h>
 #include "router.h"
+#include "dhcpv6.h"
 #include "ndp.h"
 
 
 
 static void handle_solicit(void *addr, void *data, size_t len,
-               struct interface *iface);
+               struct interface *iface, void *dest);
 static void handle_rtnetlink(void *addr, void *data, size_t len,
-               struct interface *iface);
-static struct ndp_neighbor* find_neighbor(struct in6_addr *addr, bool strict);
-static void modify_neighbor(struct in6_addr *addr, struct interface *iface,
-               bool add);
-static ssize_t ping6(struct in6_addr *addr,
-               const struct interface *iface);
-
-static struct list_head neighbors = LIST_HEAD_INIT(neighbors);
-static size_t neighbor_count = 0;
-static uint32_t rtnl_seqid = 0;
+               struct interface *iface, void *dest);
+static void catch_rtnetlink(int error);
 
+static uint32_t rtnl_seqid = 0;
 static int ping_socket = -1;
-static struct odhcpd_event ndp_event = {{.fd = -1}, handle_solicit};
-static struct odhcpd_event rtnl_event = {{.fd = -1}, handle_rtnetlink};
+static struct odhcpd_event rtnl_event = {{.fd = -1}, handle_rtnetlink, catch_rtnetlink};
 
 
 // Filter ICMPv6 messages of type neighbor soliciation
@@ -66,10 +61,15 @@ static const struct sock_fprog bpf_prog = {sizeof(bpf) / sizeof(*bpf), bpf};
 // Initialize NDP-proxy
 int init_ndp(void)
 {
+       int val = 256 * 1024;
+
        // Setup netlink socket
        if ((rtnl_event.uloop.fd = odhcpd_open_rtnl()) < 0)
                return -1;
 
+       if (setsockopt(rtnl_event.uloop.fd, SOL_SOCKET, SO_RCVBUF, &val, sizeof(val)))
+               setsockopt(rtnl_event.uloop.fd, SOL_SOCKET, SO_RCVBUFFORCE, &val, sizeof(val));
+
        // Receive netlink neighbor and ip-address events
        uint32_t group = RTNLGRP_IPV6_IFADDR;
        setsockopt(rtnl_event.uloop.fd, SOL_NETLINK,
@@ -78,41 +78,16 @@ int init_ndp(void)
        setsockopt(rtnl_event.uloop.fd, SOL_NETLINK,
                        NETLINK_ADD_MEMBERSHIP, &group, sizeof(group));
 
-       // Synthesize initial address events
-       struct {
-               struct nlmsghdr nh;
-               struct ifaddrmsg ifa;
-       } req2 = {
-               {sizeof(req2), RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP,
-                               ++rtnl_seqid, 0},
-               {.ifa_family = AF_INET6}
-       };
-       send(rtnl_event.uloop.fd, &req2, sizeof(req2), MSG_DONTWAIT);
        odhcpd_register(&rtnl_event);
 
-
-       // Create socket for intercepting NDP
-       int sock = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
-                       htons(ETH_P_ALL)); // ETH_P_ALL for ingress + egress
-       if (sock < 0) {
-               syslog(LOG_ERR, "Unable to open packet socket: %s",
-                               strerror(errno));
-               return -1;
-       }
-
-       if (setsockopt(sock, SOL_SOCKET, SO_ATTACH_FILTER,
-                       &bpf_prog, sizeof(bpf_prog))) {
-               syslog(LOG_ERR, "Failed to set BPF: %s", strerror(errno));
-               return -1;
-       }
-
-       ndp_event.uloop.fd = sock;
-       odhcpd_register(&ndp_event);
-
        // Open ICMPv6 socket
        ping_socket = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC, IPPROTO_ICMPV6);
+       if (ping_socket < 0) {
+               syslog(LOG_ERR, "Unable to open raw socket: %s", strerror(errno));
+                       return -1;
+       }
 
-       int val = 2;
+       val = 2;
        setsockopt(ping_socket, IPPROTO_RAW, IPV6_CHECKSUM, &val, sizeof(val));
 
        // This is required by RFC 4861
@@ -130,96 +105,131 @@ int init_ndp(void)
        group = RTNLGRP_NEIGH;
        setsockopt(rtnl_event.uloop.fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &group, sizeof(group));
 
-       // Synthesize initial neighbor events
+       return 0;
+}
+
+
+static void dump_neigh_table(bool proxy)
+{
        struct {
                struct nlmsghdr nh;
                struct ndmsg ndm;
        } req = {
                {sizeof(req), RTM_GETNEIGH, NLM_F_REQUEST | NLM_F_DUMP,
                                ++rtnl_seqid, 0},
-               {.ndm_family = AF_INET6}
+               {.ndm_family = AF_INET6, .ndm_flags = (proxy) ? NTF_PROXY : 0}
        };
        send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
-
-       return 0;
+       odhcpd_process(&rtnl_event);
 }
 
 
 int setup_ndp_interface(struct interface *iface, bool enable)
 {
-       struct packet_mreq mreq = {iface->ifindex, PACKET_MR_ALLMULTI, ETH_ALEN, {0}};
-       setsockopt(ndp_event.uloop.fd, SOL_PACKET, PACKET_DROP_MEMBERSHIP, &mreq, sizeof(mreq));
+       char procbuf[64];
+       snprintf(procbuf, sizeof(procbuf), "/proc/sys/net/ipv6/conf/%s/proxy_ndp", iface->ifname);
+       int procfd = open(procbuf, O_WRONLY);
+       bool dump_neigh = false;
 
-       struct ndp_neighbor *c, *n;
-       list_for_each_entry_safe(c, n, &neighbors, head)
-               if (c->iface == iface && (c->timeout == 0 || iface->ndp != RELAYD_RELAY || !enable))
-                       modify_neighbor(&c->addr, c->iface, false);
+       if (iface->ndp_event.uloop.fd > 0) {
+               uloop_fd_delete(&iface->ndp_event.uloop);
+               close(iface->ndp_event.uloop.fd);
+               iface->ndp_event.uloop.fd = -1;
 
-       if (enable && iface->ndp == RELAYD_RELAY) {
-               setsockopt(ndp_event.uloop.fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
+               if (!enable || iface->ndp != RELAYD_RELAY)
+                       if (write(procfd, "0\n", 2) < 0) {}
 
-               if (iface->static_ndp_len) {
-                       char *entry = alloca(iface->static_ndp_len), *saveptr;
-                       if (!entry) {
-                               syslog(LOG_ERR, "Alloca failed for static NDP list");
-                               return -1;
-                       }
-                       memcpy(entry, iface->static_ndp, iface->static_ndp_len);
-
-                       for (entry = strtok_r(entry, " ", &saveptr); entry; entry = strtok_r(NULL, " ", &saveptr)) {
-                               char *sep;
-                               struct ndp_neighbor *n = malloc(sizeof(*n));
-                               if (!n) {
-                                       syslog(LOG_ERR, "Malloc failed for static NDP-prefix %s", entry);
-                                       return -1;
-                               }
+               dump_neigh = true;
+       }
 
-                               n->iface = iface;
-                               n->timeout = 0;
+       if (enable && (iface->ra == RELAYD_SERVER ||
+                       iface->dhcpv6 == RELAYD_SERVER || iface->ndp == RELAYD_RELAY)) {
+               // Synthesize initial address events
+               struct {
+                       struct nlmsghdr nh;
+                       struct ifaddrmsg ifa;
+               } req2 = {
+                       {sizeof(req2), RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP,
+                                       ++rtnl_seqid, 0},
+                       {.ifa_family = AF_INET6, .ifa_index = iface->ifindex}
+               };
+               send(rtnl_event.uloop.fd, &req2, sizeof(req2), MSG_DONTWAIT);
+       }
 
-                               sep = strchr(entry, '/');
-                               if (!sep) {
-                                       free(n);
-                                       syslog(LOG_ERR, "Invalid static NDP-prefix %s", entry);
-                                       return -1;
-                               }
-                               
-                               *sep = 0;
-                               n->len = atoi(sep + 1);
-                               if (inet_pton(AF_INET6, entry, &n->addr) != 1 || n->len > 128) {
-                                       free(n);
-                                       syslog(LOG_ERR, "Invalid static NDP-prefix %s/%s", entry, sep + 1);
-                                       return -1;
-                               }
+       if (enable && iface->ndp == RELAYD_RELAY) {
+               if (write(procfd, "1\n", 2) < 0) {}
+               close(procfd);
+
+               int sock = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC, htons(ETH_P_IPV6));
+               if (sock < 0) {
+                       syslog(LOG_ERR, "Unable to open packet socket: %s",
+                                       strerror(errno));
+                       return -1;
+               }
 
-                               list_add(&n->head, &neighbors);
-                       }
+#ifdef PACKET_RECV_TYPE
+               int pktt = 1 << PACKET_MULTICAST;
+               setsockopt(sock, SOL_PACKET, PACKET_RECV_TYPE, &pktt, sizeof(pktt));
+#endif
+
+               if (setsockopt(sock, SOL_SOCKET, SO_ATTACH_FILTER,
+                               &bpf_prog, sizeof(bpf_prog))) {
+                       syslog(LOG_ERR, "Failed to set BPF: %s", strerror(errno));
+                       return -1;
                }
+
+               struct sockaddr_ll ll = {
+                       .sll_family = AF_PACKET,
+                       .sll_ifindex = iface->ifindex,
+                       .sll_protocol = htons(ETH_P_IPV6),
+                       .sll_hatype = 0,
+                       .sll_pkttype = 0,
+                       .sll_halen = 0,
+                       .sll_addr = {0},
+               };
+               bind(sock, (struct sockaddr*)&ll, sizeof(ll));
+
+               struct packet_mreq mreq = {iface->ifindex, PACKET_MR_ALLMULTI, ETH_ALEN, {0}};
+               setsockopt(sock, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
+
+               iface->ndp_event.uloop.fd = sock;
+               iface->ndp_event.handle_dgram = handle_solicit;
+               odhcpd_register(&iface->ndp_event);
+
+               // If we already were enabled dump is unnecessary, if not do dump
+               if (!dump_neigh)
+                       dump_neigh_table(false);
+               else
+                       dump_neigh = false;
+       } else {
+               close(procfd);
        }
 
+       if (dump_neigh)
+               dump_neigh_table(true);
+
        return 0;
 }
 
 
 // Send an ICMP-ECHO. This is less for actually pinging but for the
 // neighbor cache to be kept up-to-date.
-static ssize_t ping6(struct in6_addr *addr,
+static void ping6(struct in6_addr *addr,
                const struct interface *iface)
 {
-       struct sockaddr_in6 dest = {AF_INET6, 0, 0, *addr, 0};
+       struct sockaddr_in6 dest = {AF_INET6, 0, 0, *addr, iface->ifindex};
        struct icmp6_hdr echo = {.icmp6_type = ICMP6_ECHO_REQUEST};
        struct iovec iov = {&echo, sizeof(echo)};
 
-       // Linux seems to not honor IPV6_PKTINFO on raw-sockets, so work around
-       setsockopt(ping_socket, SOL_SOCKET, SO_BINDTODEVICE,
-                       iface->ifname, sizeof(iface->ifname));
-       return odhcpd_send(ping_socket, &dest, &iov, 1, iface);
+       odhcpd_setup_route(addr, 128, iface, NULL, 128, true);
+       odhcpd_send(ping_socket, &dest, &iov, 1, iface);
+       odhcpd_setup_route(addr, 128, iface, NULL, 128, false);
 }
 
 
 // Handle solicitations
 static void handle_solicit(void *addr, void *data, size_t len,
-               struct interface *iface)
+               struct interface *iface, _unused void *dest)
 {
        struct ip6_hdr *ip6 = data;
        struct nd_neighbor_solicit *req = (struct nd_neighbor_solicit*)&ip6[1];
@@ -247,231 +257,137 @@ static void handle_solicit(void *addr, void *data, size_t len,
 
        uint8_t mac[6];
        odhcpd_get_mac(iface, mac);
-       if (!memcmp(ll->sll_addr, mac, sizeof(mac)) &&
-                       ll->sll_pkttype != PACKET_OUTGOING)
+       if (!memcmp(ll->sll_addr, mac, sizeof(mac)))
                return; // Looped back
 
-       time_t now = time(NULL);
-
-       struct ndp_neighbor *n = find_neighbor(&req->nd_ns_target, false);
-       if (n && (n->iface || abs(n->timeout - now) < 5)) {
-               syslog(LOG_DEBUG, "%s is on %s", ipbuf,
-                               (n->iface) ? n->iface->ifname : "<pending>");
-               if (!n->iface || n->iface == iface)
-                       return;
-
-               // Found on other interface, answer with advertisement
-               struct {
-                       struct nd_neighbor_advert body;
-                       struct nd_opt_hdr opt_ll_hdr;
-                       uint8_t mac[6];
-               } advert = {
-                       .body = {
-                               .nd_na_hdr = {ND_NEIGHBOR_ADVERT,
-                                       0, 0, {{0}}},
-                               .nd_na_target = req->nd_ns_target,
-                       },
-                       .opt_ll_hdr = {ND_OPT_TARGET_LINKADDR, 1},
-               };
-
-               memcpy(advert.mac, mac, sizeof(advert.mac));
-               advert.body.nd_na_flags_reserved = ND_NA_FLAG_ROUTER |
-                               ND_NA_FLAG_SOLICITED;
-
-               struct sockaddr_in6 dest = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0};
-               if (!ns_is_dad) // If not DAD, then unicast to source
-                       dest.sin6_addr = ip6->ip6_src;
-
-               // Linux seems to not honor IPV6_PKTINFO on raw-sockets, so work around
-               setsockopt(ping_socket, SOL_SOCKET, SO_BINDTODEVICE,
-                                       iface->ifname, sizeof(iface->ifname));
-               struct iovec iov = {&advert, sizeof(advert)};
-               odhcpd_send(ping_socket, &dest, &iov, 1, iface);
-       } else {
-               // Send echo to all other interfaces to see where target is on
-               // This will trigger neighbor discovery which is what we want.
-               // We will observe the neighbor cache to see results.
-
-               ssize_t sent = 0;
-               struct interface *c;
-               list_for_each_entry(c, &interfaces, head)
-                       if (iface->ndp == RELAYD_RELAY && iface != c &&
-                                       (!ns_is_dad || !c->external == false))
-                               sent += ping6(&req->nd_ns_target, c);
-
-               if (sent > 0) // Sent a ping, add pending neighbor entry
-                       modify_neighbor(&req->nd_ns_target, NULL, true);
-       }
-}
-
-
-void odhcpd_setup_route(const struct in6_addr *addr, int prefixlen,
-               const struct interface *iface, const struct in6_addr *gw, bool add)
-{
-       struct req {
-               struct nlmsghdr nh;
-               struct rtmsg rtm;
-               struct rtattr rta_dst;
-               struct in6_addr dst_addr;
-               struct rtattr rta_oif;
-               uint32_t ifindex;
-               struct rtattr rta_table;
-               uint32_t table;
-               struct rtattr rta_gw;
-               struct in6_addr gw;
-       } req = {
-               {sizeof(req), 0, NLM_F_REQUEST, ++rtnl_seqid, 0},
-               {AF_INET6, prefixlen, 0, 0, 0, 0, 0, 0, 0},
-               {sizeof(struct rtattr) + sizeof(struct in6_addr), RTA_DST},
-               *addr,
-               {sizeof(struct rtattr) + sizeof(uint32_t), RTA_OIF},
-               iface->ifindex,
-               {sizeof(struct rtattr) + sizeof(uint32_t), RTA_TABLE},
-               RT_TABLE_MAIN,
-               {sizeof(struct rtattr) + sizeof(struct in6_addr), RTA_GATEWAY},
-               IN6ADDR_ANY_INIT,
-       };
-
-       if (gw)
-               req.gw = *gw;
-
-       if (add) {
-               req.nh.nlmsg_type = RTM_NEWROUTE;
-               req.nh.nlmsg_flags |= (NLM_F_CREATE | NLM_F_REPLACE);
-               req.rtm.rtm_protocol = RTPROT_BOOT;
-               req.rtm.rtm_scope = (gw) ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK;
-               req.rtm.rtm_type = RTN_UNICAST;
-       } else {
-               req.nh.nlmsg_type = RTM_DELROUTE;
-               req.rtm.rtm_scope = RT_SCOPE_NOWHERE;
-       }
-
-       size_t reqlen = (gw) ? sizeof(req) : offsetof(struct req, rta_gw);
-       send(rtnl_event.uloop.fd, &req, reqlen, MSG_DONTWAIT);
+       struct interface *c;
+       list_for_each_entry(c, &interfaces, head)
+               if (iface->ndp == RELAYD_RELAY && iface != c &&
+                               (ns_is_dad || !c->external))
+                       ping6(&req->nd_ns_target, c);
 }
 
 // Use rtnetlink to modify kernel routes
-static void setup_route(struct in6_addr *addr, struct interface *iface,
-               bool add)
+static void setup_route(struct in6_addr *addr, struct interface *iface, bool add)
 {
        char namebuf[INET6_ADDRSTRLEN];
        inet_ntop(AF_INET6, addr, namebuf, sizeof(namebuf));
-       syslog(LOG_NOTICE, "%s about %s on %s", (add) ? "Learned" : "Forgot",
-                       namebuf, (iface) ? iface->ifname : "<pending>");
-
-       if (!iface || !iface->learn_routes)
-               return;
+       syslog(LOG_NOTICE, "%s about %s on %s",
+                       (add) ? "Learned" : "Forgot", namebuf, iface->ifname);
 
-       odhcpd_setup_route(addr, 128, iface, NULL, add);
+       if (iface->learn_routes)
+               odhcpd_setup_route(addr, 128, iface, NULL, 1024, add);
 }
 
-static void free_neighbor(struct ndp_neighbor *n)
+// compare prefixes
+static int prefixcmp(const void *va, const void *vb)
 {
-       setup_route(&n->addr, n->iface, false);
-       list_del(&n->head);
-       free(n);
-       --neighbor_count;
+       const struct odhcpd_ipaddr *a = va, *b = vb;
+       uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
+       uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
+       return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 }
 
-static struct ndp_neighbor* find_neighbor(struct in6_addr *addr, bool strict)
+// Check address update
+static void check_updates(struct interface *iface)
 {
-       time_t now = time(NULL);
-       struct ndp_neighbor *n, *e;
-       list_for_each_entry_safe(n, e, &neighbors, head) {
-               if ((!strict && !odhcpd_bmemcmp(&n->addr, addr, n->len)) ||
-                               (n->len == 128 && IN6_ARE_ADDR_EQUAL(&n->addr, addr)))
-                       return n;
-
-               if (!n->iface && abs(n->timeout - now) >= 5)
-                       free_neighbor(n);
+       struct odhcpd_ipaddr addr[RELAYD_MAX_ADDRS] = {{IN6ADDR_ANY_INIT, 0, 0, 0, 0}};
+       time_t now = odhcpd_time();
+       ssize_t len = odhcpd_get_interface_addresses(iface->ifindex, addr, ARRAY_SIZE(addr));
+
+       if (len < 0)
+               return;
+
+       qsort(addr, len, sizeof(*addr), prefixcmp);
+
+       for (int i = 0; i < len; ++i) {
+               addr[i].addr.s6_addr32[3] = 0;
+
+               if (addr[i].preferred < UINT32_MAX - now)
+                       addr[i].preferred += now;
+
+               if (addr[i].valid < UINT32_MAX - now)
+                       addr[i].valid += now;
        }
-       return NULL;
-}
 
+       bool change = len != (ssize_t)iface->ia_addr_len;
+       for (ssize_t i = 0; !change && i < len; ++i)
+               if (!IN6_ARE_ADDR_EQUAL(&addr[i].addr, &iface->ia_addr[i].addr) ||
+                               (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
+                               addr[i].valid < iface->ia_addr[i].valid ||
+                               addr[i].preferred < iface->ia_addr[i].preferred)
+                       change = true;
 
-// Modified our own neighbor-entries
-static void modify_neighbor(struct in6_addr *addr,
-               struct interface *iface, bool add)
-{
-       if (!addr || (void*)addr == (void*)iface)
-               return;
+       if (change)
+               dhcpv6_ia_preupdate(iface);
+
+       memcpy(iface->ia_addr, addr, len * sizeof(*addr));
+       iface->ia_addr_len = len;
 
-       struct ndp_neighbor *n = find_neighbor(addr, true);
-       if (!add) { // Delete action
-               if (n && (!n->iface || n->iface == iface))
-                       free_neighbor(n);
-       } else if (!n) { // No entry yet, add one if possible
-               if (neighbor_count >= NDP_MAX_NEIGHBORS ||
-                               !(n = malloc(sizeof(*n))))
-                       return;
-
-               n->len = 128;
-               n->addr = *addr;
-               n->iface = iface;
-               if (!n->iface)
-                       time(&n->timeout);
-               list_add(&n->head, &neighbors);
-               ++neighbor_count;
-               setup_route(addr, n->iface, add);
-       } else if (n->iface == iface) {
-               if (!n->iface)
-                       time(&n->timeout);
-       } else if (iface && (!n->iface ||
-                       (!iface->external && n->iface->external))) {
-               setup_route(addr, n->iface, false);
-               n->iface = iface;
-               setup_route(addr, n->iface, add);
+       if (change)
+               dhcpv6_ia_postupdate(iface, now);
+
+       if (change) {
+               syslog(LOG_DEBUG, "Raising SIGUSR1 due to address change");
+               raise(SIGUSR1);
        }
-       // TODO: In case a host switches interfaces we might want
-       // to set its old neighbor entry to NUD_STALE and ping it
-       // on the old interface to confirm if the MACs match.
 }
 
 
 // Handler for neighbor cache entries from the kernel. This is our source
 // to learn and unlearn hosts on interfaces.
 static void handle_rtnetlink(_unused void *addr, void *data, size_t len,
-               _unused struct interface *iface)
+               _unused struct interface *iface, _unused void *dest)
 {
+       bool dump_neigh = false;
+       struct in6_addr last_solicited = IN6ADDR_ANY_INIT;
+
        for (struct nlmsghdr *nh = data; NLMSG_OK(nh, len);
                        nh = NLMSG_NEXT(nh, len)) {
+               struct ndmsg *ndm = NLMSG_DATA(nh);
                struct rtmsg *rtm = NLMSG_DATA(nh);
-               if ((nh->nlmsg_type == RTM_NEWROUTE ||
-                               nh->nlmsg_type == RTM_DELROUTE) &&
-                               rtm->rtm_dst_len == 0)
-                       raise(SIGUSR1); // Inform about a change in default route
 
-               struct ndmsg *ndm = NLMSG_DATA(nh);
-               struct ifaddrmsg *ifa = NLMSG_DATA(nh);
-               if (nh->nlmsg_type != RTM_NEWNEIGH
-                               && nh->nlmsg_type != RTM_DELNEIGH
-                               && nh->nlmsg_type != RTM_NEWADDR
-                               && nh->nlmsg_type != RTM_DELADDR)
-                       continue; // Unrelated message type
                bool is_addr = (nh->nlmsg_type == RTM_NEWADDR
                                || nh->nlmsg_type == RTM_DELADDR);
+               bool is_route = (nh->nlmsg_type == RTM_NEWROUTE
+                               || nh->nlmsg_type == RTM_DELROUTE);
+               bool is_neigh = (nh->nlmsg_type == RTM_NEWNEIGH
+                               || nh->nlmsg_type == RTM_DELNEIGH);
 
                // Family and ifindex are on the same offset for NEIGH and ADDR
-               if (NLMSG_PAYLOAD(nh, 0) < sizeof(*ndm)
+               if ((!is_addr && !is_route && !is_neigh)
+                               || NLMSG_PAYLOAD(nh, 0) < sizeof(*ndm)
                                || ndm->ndm_family != AF_INET6)
-                       continue; //
+                       continue;
+
+               if (is_route) {
+                       // Inform about a change in default route
+                       if (rtm->rtm_dst_len == 0) {
+                               syslog(LOG_DEBUG, "Raising SIGUSR1 due to default route change");
+                               raise(SIGUSR1);
+                       }
 
-               // Lookup interface
-               struct interface *iface;
-               if (!(iface = odhcpd_get_interface_by_index(ndm->ndm_ifindex)))
                        continue;
+               }
 
                // Data to retrieve
-               size_t rta_offset = (is_addr) ? sizeof(*ifa) : sizeof(*ndm);
+               size_t rta_offset = (is_addr) ? sizeof(struct ifaddrmsg) : sizeof(*ndm);
                uint16_t atype = (is_addr) ? IFA_ADDRESS : NDA_DST;
                ssize_t alen = NLMSG_PAYLOAD(nh, rta_offset);
                struct in6_addr *addr = NULL;
 
                for (struct rtattr *rta = (void*)(((uint8_t*)ndm) + rta_offset);
-                               RTA_OK(rta, alen); rta = RTA_NEXT(rta, alen))
+                               RTA_OK(rta, alen); rta = RTA_NEXT(rta, alen)) {
                        if (rta->rta_type == atype &&
-                                       RTA_PAYLOAD(rta) >= sizeof(*addr))
+                                       RTA_PAYLOAD(rta) >= sizeof(*addr)) {
                                addr = RTA_DATA(rta);
+                       }
+               }
+
+               // Lookup interface
+               struct interface *iface = odhcpd_get_interface_by_index(ndm->ndm_ifindex);
+               if (!iface)
+                       continue;
 
                // Address not specified or unrelated
                if (!addr || IN6_IS_ADDR_LINKLOCAL(addr) ||
@@ -487,35 +403,118 @@ static void handle_rtnetlink(_unused void *addr, void *data, size_t len,
                                (NUD_REACHABLE | NUD_STALE | NUD_DELAY | NUD_PROBE
                                                | NUD_PERMANENT | NUD_NOARP)));
 
-               if (iface->ndp == RELAYD_RELAY)
-                       modify_neighbor(addr, iface, add);
+               if (iface->ndp == RELAYD_RELAY) {
+                       // Replay change to all neighbor cache
+                       struct {
+                               struct nlmsghdr nh;
+                               struct ndmsg ndm;
+                               struct nlattr nla_dst;
+                               struct in6_addr dst;
+                       } req = {
+                               {sizeof(req), RTM_DELNEIGH, NLM_F_REQUEST,
+                                               ++rtnl_seqid, 0},
+                               {.ndm_family = AF_INET6, .ndm_flags = NTF_PROXY},
+                               {sizeof(struct nlattr) + sizeof(struct in6_addr), NDA_DST},
+                               *addr
+                       };
+
+                       if (ndm->ndm_flags & NTF_PROXY) {
+                               // Dump & flush proxy entries
+                               if (nh->nlmsg_type == RTM_NEWNEIGH) {
+                                       req.ndm.ndm_ifindex = iface->ifindex;
+                                       send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
+                                       setup_route(addr, iface, false);
+                                       dump_neigh = true;
+                               }
+                       } else if (add) {
+                               struct interface *c;
+                               list_for_each_entry(c, &interfaces, head) {
+                                       if (iface == c)
+                                               continue;
+
+                                       if (c->ndp == RELAYD_RELAY) {
+                                               req.nh.nlmsg_type = RTM_NEWNEIGH;
+                                               req.nh.nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
+
+                                               req.ndm.ndm_ifindex = c->ifindex;
+                                               send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
+                                       } else { // Delete NDP cache from interfaces without relay
+                                               req.nh.nlmsg_type = RTM_DELNEIGH;
+                                               req.nh.nlmsg_flags &= ~(NLM_F_CREATE | NLM_F_REPLACE);
+
+                                               req.ndm.ndm_ifindex = c->ifindex;
+                                               send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
+                                       }
+                               }
+
+                               setup_route(addr, iface, true);
+                       } else {
+                               if (nh->nlmsg_type == RTM_NEWNEIGH) {
+                                       // might be locally originating
+                                       if (!IN6_ARE_ADDR_EQUAL(&last_solicited, addr)) {
+                                               last_solicited = *addr;
+
+                                               struct interface *c;
+                                               list_for_each_entry(c, &interfaces, head)
+                                                       if (iface->ndp == RELAYD_RELAY && iface != c &&
+                                                                       !c->external == false)
+                                                               ping6(addr, c);
+                                       }
+                               } else {
+                                       struct interface *c;
+                                       list_for_each_entry(c, &interfaces, head) {
+                                               if (c->ndp == RELAYD_RELAY && iface != c) {
+                                                       req.ndm.ndm_ifindex = c->ifindex;
+                                                       send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
+                                               }
+                                       }
+                                       setup_route(addr, iface, false);
+
+                                       // also: dump to add proxies back in case it moved elsewhere
+                                       dump_neigh = true;
+                               }
+                       }
+               }
 
-               if (is_addr && iface->ra == RELAYD_SERVER)
-                       raise(SIGUSR1); // Inform about a change in addresses
+               if (is_addr) {
+                       check_updates(iface);
 
-               if (is_addr && iface->dhcpv6 == RELAYD_SERVER)
-                       iface->ia_reconf = true;
+                       if (iface->dhcpv6 == RELAYD_SERVER)
+                               iface->ia_reconf = true;
 
-               if (iface->ndp == RELAYD_RELAY && is_addr && iface->master) {
-                       // Replay address changes on all slave interfaces
-                       nh->nlmsg_flags = NLM_F_REQUEST;
+                       if (iface->ndp == RELAYD_RELAY && iface->master) {
+                               // Replay address changes on all slave interfaces
+                               nh->nlmsg_flags = NLM_F_REQUEST;
 
-                       if (nh->nlmsg_type == RTM_NEWADDR)
-                               nh->nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
+                               if (nh->nlmsg_type == RTM_NEWADDR)
+                                       nh->nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
 
-                       struct interface *c;
-                       list_for_each_entry(c, &interfaces, head) {
-                               if (c->ndp == RELAYD_RELAY && !c->master) {
-                                       ifa->ifa_index = c->ifindex;
-                                       send(rtnl_event.uloop.fd, nh, nh->nlmsg_len, MSG_DONTWAIT);
+                               struct interface *c;
+                               list_for_each_entry(c, &interfaces, head) {
+                                       if (c->ndp == RELAYD_RELAY && !c->master) {
+                                               ndm->ndm_ifindex = c->ifindex;
+                                               send(rtnl_event.uloop.fd, nh, nh->nlmsg_len, MSG_DONTWAIT);
+                                       }
                                }
                        }
                }
+       }
+
+       if (dump_neigh)
+               dump_neigh_table(false);
+}
 
-               /* TODO: See if this is required for optimal operation
-               // Keep neighbor entries alive so we don't loose routes
-                */
-               if (add && (ndm->ndm_state & NUD_STALE))
-                       ping6(addr, iface);
+static void catch_rtnetlink(int error)
+{
+       if (error == ENOBUFS) {
+               struct {
+                       struct nlmsghdr nh;
+                       struct ifaddrmsg ifa;
+               } req2 = {
+                       {sizeof(req2), RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP,
+                                       ++rtnl_seqid, 0},
+                       {.ifa_family = AF_INET6}
+               };
+               send(rtnl_event.uloop.fd, &req2, sizeof(req2), MSG_DONTWAIT);
        }
 }