#include <signal.h>
#include <errno.h>
-#include <fcntl.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
struct interface *iface, void *dest);
static void handle_rtnetlink(void *addr, void *data, size_t len,
struct interface *iface, void *dest);
+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;
+
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};
group = RTNLGRP_NEIGH;
setsockopt(rtnl_event.uloop.fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &group, sizeof(group));
+ // Synthesize initial neighbor events
+ 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}
+ };
+ send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
+
return 0;
}
int setup_ndp_interface(struct interface *iface, bool enable)
{
- char procbuf[64];
- snprintf(procbuf, sizeof(procbuf), "/proc/sys/net/ipv6/conf/%s/proxy_ndp", iface->ifname);
- int procfd = open(procbuf, O_WRONLY);
+ 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));
+
+ 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 (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;
+ }
+
+ n->iface = iface;
+ n->timeout = 0;
+
+ 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;
+ }
- write(procfd, "0\n", 2);
+ list_add(&n->head, &neighbors);
+ }
+ }
}
- if (enable && iface->ndp == RELAYD_RELAY) {
- write(procfd, "1\n", 2);
+ bool enable_packet = false;
+ struct interface *i;
+ list_for_each_entry(i, &interfaces, head) {
+ if (i == iface && !enable)
+ continue;
- int sock = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC, htons(ETH_P_IPV6));
+ if (i->ndp == RELAYD_RELAY)
+ enable_packet = true;
+ }
+
+ if (enable_packet && ndp_event.uloop.fd < 0) {
+ // 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;
}
-#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),
- };
- 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);
-
- // Dump neighbor events
- 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}
- };
- send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
+ ndp_event.uloop.fd = sock;
+ odhcpd_register(&ndp_event);
+ } else if (!enable_packet && ndp_event.uloop.fd >= 0) {
+ close(ndp_event.uloop.fd);
+ ndp_event.uloop.fd = -1;
}
- close(procfd);
return 0;
}
uint8_t mac[6];
odhcpd_get_mac(iface, mac);
- if (!memcmp(ll->sll_addr, mac, sizeof(mac)))
+ if (!memcmp(ll->sll_addr, mac, sizeof(mac)) &&
+ ll->sll_pkttype != PACKET_OUTGOING)
return; // Looped back
- struct interface *c;
- list_for_each_entry(c, &interfaces, head)
- if (iface->ndp == RELAYD_RELAY && iface != c &&
- (!ns_is_dad || !c->external == false))
- ping6(&req->nd_ns_target, c);
+ 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);
+ }
}
odhcpd_setup_route(addr, 128, iface, NULL, add);
}
+static void free_neighbor(struct ndp_neighbor *n)
+{
+ setup_route(&n->addr, n->iface, false);
+ list_del(&n->head);
+ free(n);
+ --neighbor_count;
+}
+
+static struct ndp_neighbor* find_neighbor(struct in6_addr *addr, bool strict)
+{
+ 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);
+ }
+ return NULL;
+}
+
+
+// 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;
+
+ 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);
+ }
+ // 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 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 rtmsg *rtm = NLMSG_DATA(nh);
(NUD_REACHABLE | NUD_STALE | NUD_DELAY | NUD_PROBE
| NUD_PERMANENT | NUD_NOARP)));
- 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 (add) {
- req.nh.nlmsg_type = RTM_NEWNEIGH;
- req.nh.nlmsg_flags |= NLM_F_CREATE;
-
- 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, 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 (iface->ndp == RELAYD_RELAY)
+ modify_neighbor(addr, iface, add);
if (is_addr && iface->ra == RELAYD_SERVER)
raise(SIGUSR1); // Inform about a change in addresses
}
}
}
- }
- if (dump_neigh) {
- 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}
- };
- send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
+ /* 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);
}
}
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