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-rw-r--r--src/libsystemd-network/sd-lldp.c498
1 files changed, 498 insertions, 0 deletions
diff --git a/src/libsystemd-network/sd-lldp.c b/src/libsystemd-network/sd-lldp.c
new file mode 100644
index 0000000..8b66652
--- /dev/null
+++ b/src/libsystemd-network/sd-lldp.c
@@ -0,0 +1,498 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <arpa/inet.h>
+#include <linux/sockios.h>
+#include <sys/ioctl.h>
+
+#include "sd-lldp.h"
+
+#include "alloc-util.h"
+#include "ether-addr-util.h"
+#include "event-util.h"
+#include "fd-util.h"
+#include "lldp-internal.h"
+#include "lldp-neighbor.h"
+#include "lldp-network.h"
+#include "memory-util.h"
+#include "socket-util.h"
+#include "sort-util.h"
+#include "string-table.h"
+
+#define LLDP_DEFAULT_NEIGHBORS_MAX 128U
+
+static const char * const lldp_event_table[_SD_LLDP_EVENT_MAX] = {
+ [SD_LLDP_EVENT_ADDED] = "added",
+ [SD_LLDP_EVENT_REMOVED] = "removed",
+ [SD_LLDP_EVENT_UPDATED] = "updated",
+ [SD_LLDP_EVENT_REFRESHED] = "refreshed",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(lldp_event, sd_lldp_event);
+
+static void lldp_flush_neighbors(sd_lldp *lldp) {
+ assert(lldp);
+
+ hashmap_clear(lldp->neighbor_by_id);
+}
+
+static void lldp_callback(sd_lldp *lldp, sd_lldp_event event, sd_lldp_neighbor *n) {
+ assert(lldp);
+ assert(event >= 0 && event < _SD_LLDP_EVENT_MAX);
+
+ if (!lldp->callback) {
+ log_lldp("Received '%s' event.", lldp_event_to_string(event));
+ return;
+ }
+
+ log_lldp("Invoking callback for '%s' event.", lldp_event_to_string(event));
+ lldp->callback(lldp, event, n, lldp->userdata);
+}
+
+static int lldp_make_space(sd_lldp *lldp, size_t extra) {
+ usec_t t = USEC_INFINITY;
+ bool changed = false;
+
+ assert(lldp);
+
+ /* Remove all entries that are past their TTL, and more until at least the specified number of extra entries
+ * are free. */
+
+ for (;;) {
+ _cleanup_(sd_lldp_neighbor_unrefp) sd_lldp_neighbor *n = NULL;
+
+ n = prioq_peek(lldp->neighbor_by_expiry);
+ if (!n)
+ break;
+
+ sd_lldp_neighbor_ref(n);
+
+ if (hashmap_size(lldp->neighbor_by_id) > LESS_BY(lldp->neighbors_max, extra))
+ goto remove_one;
+
+ if (t == USEC_INFINITY)
+ t = now(clock_boottime_or_monotonic());
+
+ if (n->until > t)
+ break;
+
+ remove_one:
+ lldp_neighbor_unlink(n);
+ lldp_callback(lldp, SD_LLDP_EVENT_REMOVED, n);
+ changed = true;
+ }
+
+ return changed;
+}
+
+static bool lldp_keep_neighbor(sd_lldp *lldp, sd_lldp_neighbor *n) {
+ assert(lldp);
+ assert(n);
+
+ /* Don't keep data with a zero TTL */
+ if (n->ttl <= 0)
+ return false;
+
+ /* Filter out data from the filter address */
+ if (!ether_addr_is_null(&lldp->filter_address) &&
+ ether_addr_equal(&lldp->filter_address, &n->source_address))
+ return false;
+
+ /* Only add if the neighbor has a capability we are interested in. Note that we also store all neighbors with
+ * no caps field set. */
+ if (n->has_capabilities &&
+ (n->enabled_capabilities & lldp->capability_mask) == 0)
+ return false;
+
+ /* Keep everything else */
+ return true;
+}
+
+static int lldp_start_timer(sd_lldp *lldp, sd_lldp_neighbor *neighbor);
+
+static int lldp_add_neighbor(sd_lldp *lldp, sd_lldp_neighbor *n) {
+ _cleanup_(sd_lldp_neighbor_unrefp) sd_lldp_neighbor *old = NULL;
+ bool keep;
+ int r;
+
+ assert(lldp);
+ assert(n);
+ assert(!n->lldp);
+
+ keep = lldp_keep_neighbor(lldp, n);
+
+ /* First retrieve the old entry for this MSAP */
+ old = hashmap_get(lldp->neighbor_by_id, &n->id);
+ if (old) {
+ sd_lldp_neighbor_ref(old);
+
+ if (!keep) {
+ lldp_neighbor_unlink(old);
+ lldp_callback(lldp, SD_LLDP_EVENT_REMOVED, old);
+ return 0;
+ }
+
+ if (lldp_neighbor_equal(n, old)) {
+ /* Is this equal, then restart the TTL counter, but don't do anything else. */
+ old->timestamp = n->timestamp;
+ lldp_start_timer(lldp, old);
+ lldp_callback(lldp, SD_LLDP_EVENT_REFRESHED, old);
+ return 0;
+ }
+
+ /* Data changed, remove the old entry, and add a new one */
+ lldp_neighbor_unlink(old);
+
+ } else if (!keep)
+ return 0;
+
+ /* Then, make room for at least one new neighbor */
+ lldp_make_space(lldp, 1);
+
+ r = hashmap_put(lldp->neighbor_by_id, &n->id, n);
+ if (r < 0)
+ goto finish;
+
+ r = prioq_put(lldp->neighbor_by_expiry, n, &n->prioq_idx);
+ if (r < 0) {
+ assert_se(hashmap_remove(lldp->neighbor_by_id, &n->id) == n);
+ goto finish;
+ }
+
+ n->lldp = lldp;
+
+ lldp_start_timer(lldp, n);
+ lldp_callback(lldp, old ? SD_LLDP_EVENT_UPDATED : SD_LLDP_EVENT_ADDED, n);
+
+ return 1;
+
+finish:
+ if (old)
+ lldp_callback(lldp, SD_LLDP_EVENT_REMOVED, old);
+
+ return r;
+}
+
+static int lldp_handle_datagram(sd_lldp *lldp, sd_lldp_neighbor *n) {
+ int r;
+
+ assert(lldp);
+ assert(n);
+
+ r = lldp_neighbor_parse(n);
+ if (r == -EBADMSG) /* Ignore bad messages */
+ return 0;
+ if (r < 0)
+ return r;
+
+ r = lldp_add_neighbor(lldp, n);
+ if (r < 0) {
+ log_lldp_errno(r, "Failed to add datagram. Ignoring.");
+ return 0;
+ }
+
+ log_lldp("Successfully processed LLDP datagram.");
+ return 0;
+}
+
+static int lldp_receive_datagram(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+ _cleanup_(sd_lldp_neighbor_unrefp) sd_lldp_neighbor *n = NULL;
+ ssize_t space, length;
+ sd_lldp *lldp = userdata;
+ struct timespec ts;
+
+ assert(fd >= 0);
+ assert(lldp);
+
+ space = next_datagram_size_fd(fd);
+ if (space < 0)
+ return log_lldp_errno(space, "Failed to determine datagram size to read: %m");
+
+ n = lldp_neighbor_new(space);
+ if (!n)
+ return -ENOMEM;
+
+ length = recv(fd, LLDP_NEIGHBOR_RAW(n), n->raw_size, MSG_DONTWAIT);
+ if (length < 0) {
+ if (IN_SET(errno, EAGAIN, EINTR))
+ return 0;
+
+ return log_lldp_errno(errno, "Failed to read LLDP datagram: %m");
+ }
+
+ if ((size_t) length != n->raw_size) {
+ log_lldp("Packet size mismatch.");
+ return -EINVAL;
+ }
+
+ /* Try to get the timestamp of this packet if it is known */
+ if (ioctl(fd, SIOCGSTAMPNS, &ts) >= 0)
+ triple_timestamp_from_realtime(&n->timestamp, timespec_load(&ts));
+ else
+ triple_timestamp_get(&n->timestamp);
+
+ return lldp_handle_datagram(lldp, n);
+}
+
+static void lldp_reset(sd_lldp *lldp) {
+ assert(lldp);
+
+ (void) event_source_disable(lldp->timer_event_source);
+ lldp->io_event_source = sd_event_source_unref(lldp->io_event_source);
+ lldp->fd = safe_close(lldp->fd);
+}
+
+_public_ int sd_lldp_start(sd_lldp *lldp) {
+ int r;
+
+ assert_return(lldp, -EINVAL);
+ assert_return(lldp->event, -EINVAL);
+ assert_return(lldp->ifindex > 0, -EINVAL);
+
+ if (lldp->fd >= 0)
+ return 0;
+
+ assert(!lldp->io_event_source);
+
+ lldp->fd = lldp_network_bind_raw_socket(lldp->ifindex);
+ if (lldp->fd < 0)
+ return lldp->fd;
+
+ r = sd_event_add_io(lldp->event, &lldp->io_event_source, lldp->fd, EPOLLIN, lldp_receive_datagram, lldp);
+ if (r < 0)
+ goto fail;
+
+ r = sd_event_source_set_priority(lldp->io_event_source, lldp->event_priority);
+ if (r < 0)
+ goto fail;
+
+ (void) sd_event_source_set_description(lldp->io_event_source, "lldp-io");
+
+ log_lldp("Started LLDP client");
+ return 1;
+
+fail:
+ lldp_reset(lldp);
+ return r;
+}
+
+_public_ int sd_lldp_stop(sd_lldp *lldp) {
+ if (!lldp)
+ return 0;
+
+ if (lldp->fd < 0)
+ return 0;
+
+ log_lldp("Stopping LLDP client");
+
+ lldp_reset(lldp);
+ lldp_flush_neighbors(lldp);
+
+ return 1;
+}
+
+_public_ int sd_lldp_attach_event(sd_lldp *lldp, sd_event *event, int64_t priority) {
+ int r;
+
+ assert_return(lldp, -EINVAL);
+ assert_return(lldp->fd < 0, -EBUSY);
+ assert_return(!lldp->event, -EBUSY);
+
+ if (event)
+ lldp->event = sd_event_ref(event);
+ else {
+ r = sd_event_default(&lldp->event);
+ if (r < 0)
+ return r;
+ }
+
+ lldp->event_priority = priority;
+
+ return 0;
+}
+
+_public_ int sd_lldp_detach_event(sd_lldp *lldp) {
+
+ assert_return(lldp, -EINVAL);
+ assert_return(lldp->fd < 0, -EBUSY);
+
+ lldp->event = sd_event_unref(lldp->event);
+ return 0;
+}
+
+_public_ sd_event* sd_lldp_get_event(sd_lldp *lldp) {
+ assert_return(lldp, NULL);
+
+ return lldp->event;
+}
+
+_public_ int sd_lldp_set_callback(sd_lldp *lldp, sd_lldp_callback_t cb, void *userdata) {
+ assert_return(lldp, -EINVAL);
+
+ lldp->callback = cb;
+ lldp->userdata = userdata;
+
+ return 0;
+}
+
+_public_ int sd_lldp_set_ifindex(sd_lldp *lldp, int ifindex) {
+ assert_return(lldp, -EINVAL);
+ assert_return(ifindex > 0, -EINVAL);
+ assert_return(lldp->fd < 0, -EBUSY);
+
+ lldp->ifindex = ifindex;
+ return 0;
+}
+
+static sd_lldp* lldp_free(sd_lldp *lldp) {
+ assert(lldp);
+
+ lldp->timer_event_source = sd_event_source_unref(lldp->timer_event_source);
+
+ lldp_reset(lldp);
+ sd_lldp_detach_event(lldp);
+ lldp_flush_neighbors(lldp);
+
+ hashmap_free(lldp->neighbor_by_id);
+ prioq_free(lldp->neighbor_by_expiry);
+ return mfree(lldp);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_lldp, sd_lldp, lldp_free);
+
+_public_ int sd_lldp_new(sd_lldp **ret) {
+ _cleanup_(sd_lldp_unrefp) sd_lldp *lldp = NULL;
+ int r;
+
+ assert_return(ret, -EINVAL);
+
+ lldp = new(sd_lldp, 1);
+ if (!lldp)
+ return -ENOMEM;
+
+ *lldp = (sd_lldp) {
+ .n_ref = 1,
+ .fd = -1,
+ .neighbors_max = LLDP_DEFAULT_NEIGHBORS_MAX,
+ .capability_mask = (uint16_t) -1,
+ };
+
+ lldp->neighbor_by_id = hashmap_new(&lldp_neighbor_hash_ops);
+ if (!lldp->neighbor_by_id)
+ return -ENOMEM;
+
+ r = prioq_ensure_allocated(&lldp->neighbor_by_expiry, lldp_neighbor_prioq_compare_func);
+ if (r < 0)
+ return r;
+
+ *ret = TAKE_PTR(lldp);
+
+ return 0;
+}
+
+static int neighbor_compare_func(sd_lldp_neighbor * const *a, sd_lldp_neighbor * const *b) {
+ return lldp_neighbor_id_compare_func(&(*a)->id, &(*b)->id);
+}
+
+static int on_timer_event(sd_event_source *s, uint64_t usec, void *userdata) {
+ sd_lldp *lldp = userdata;
+ int r;
+
+ r = lldp_make_space(lldp, 0);
+ if (r < 0)
+ return log_lldp_errno(r, "Failed to make space: %m");
+
+ r = lldp_start_timer(lldp, NULL);
+ if (r < 0)
+ return log_lldp_errno(r, "Failed to restart timer: %m");
+
+ return 0;
+}
+
+static int lldp_start_timer(sd_lldp *lldp, sd_lldp_neighbor *neighbor) {
+ sd_lldp_neighbor *n;
+
+ assert(lldp);
+
+ if (neighbor)
+ lldp_neighbor_start_ttl(neighbor);
+
+ n = prioq_peek(lldp->neighbor_by_expiry);
+ if (!n)
+ return event_source_disable(lldp->timer_event_source);
+
+ if (!lldp->event)
+ return 0;
+
+ return event_reset_time(lldp->event, &lldp->timer_event_source,
+ clock_boottime_or_monotonic(),
+ n->until, 0,
+ on_timer_event, lldp,
+ lldp->event_priority, "lldp-timer", true);
+}
+
+_public_ int sd_lldp_get_neighbors(sd_lldp *lldp, sd_lldp_neighbor ***ret) {
+ sd_lldp_neighbor **l = NULL, *n;
+ int k = 0, r;
+
+ assert_return(lldp, -EINVAL);
+ assert_return(ret, -EINVAL);
+
+ if (hashmap_isempty(lldp->neighbor_by_id)) { /* Special shortcut */
+ *ret = NULL;
+ return 0;
+ }
+
+ l = new0(sd_lldp_neighbor*, hashmap_size(lldp->neighbor_by_id));
+ if (!l)
+ return -ENOMEM;
+
+ r = lldp_start_timer(lldp, NULL);
+ if (r < 0) {
+ free(l);
+ return r;
+ }
+
+ HASHMAP_FOREACH(n, lldp->neighbor_by_id)
+ l[k++] = sd_lldp_neighbor_ref(n);
+
+ assert((size_t) k == hashmap_size(lldp->neighbor_by_id));
+
+ /* Return things in a stable order */
+ typesafe_qsort(l, k, neighbor_compare_func);
+ *ret = l;
+
+ return k;
+}
+
+_public_ int sd_lldp_set_neighbors_max(sd_lldp *lldp, uint64_t m) {
+ assert_return(lldp, -EINVAL);
+ assert_return(m > 0, -EINVAL);
+
+ lldp->neighbors_max = m;
+ lldp_make_space(lldp, 0);
+
+ return 0;
+}
+
+_public_ int sd_lldp_match_capabilities(sd_lldp *lldp, uint16_t mask) {
+ assert_return(lldp, -EINVAL);
+ assert_return(mask != 0, -EINVAL);
+
+ lldp->capability_mask = mask;
+
+ return 0;
+}
+
+_public_ int sd_lldp_set_filter_address(sd_lldp *lldp, const struct ether_addr *addr) {
+ assert_return(lldp, -EINVAL);
+
+ /* In order to deal nicely with bridges that send back our own packets, allow one address to be filtered, so
+ * that our own can be filtered out here. */
+
+ if (addr)
+ lldp->filter_address = *addr;
+ else
+ zero(lldp->filter_address);
+
+ return 0;
+}
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