538 lines
15 KiB
C
538 lines
15 KiB
C
/***
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This file is part of systemd.
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Copyright (C) 2014 Tom Gundersen
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Copyright (C) 2014 Susant Sahani
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <arpa/inet.h>
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#include "sd-lldp.h"
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#include "alloc-util.h"
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#include "fd-util.h"
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#include "lldp-internal.h"
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#include "lldp-neighbor.h"
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#include "lldp-network.h"
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#include "socket-util.h"
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#include "ether-addr-util.h"
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#define LLDP_DEFAULT_NEIGHBORS_MAX 128U
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static void lldp_flush_neighbors(sd_lldp *lldp) {
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sd_lldp_neighbor *n;
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assert(lldp);
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while ((n = hashmap_first(lldp->neighbor_by_id)))
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lldp_neighbor_unlink(n);
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}
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static void lldp_callback(sd_lldp *lldp, sd_lldp_event event, sd_lldp_neighbor *n) {
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assert(lldp);
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log_lldp("Invoking callback for '%c'.", event);
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if (!lldp->callback)
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return;
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lldp->callback(lldp, event, n, lldp->userdata);
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}
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static int lldp_make_space(sd_lldp *lldp, size_t extra) {
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usec_t t = USEC_INFINITY;
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bool changed = false;
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assert(lldp);
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/* Remove all entries that are past their TTL, and more until at least the specified number of extra entries
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* are free. */
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for (;;) {
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_cleanup_(sd_lldp_neighbor_unrefp) sd_lldp_neighbor *n = NULL;
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n = prioq_peek(lldp->neighbor_by_expiry);
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if (!n)
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break;
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sd_lldp_neighbor_ref(n);
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if (hashmap_size(lldp->neighbor_by_id) > LESS_BY(lldp->neighbors_max, extra))
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goto remove_one;
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if (t == USEC_INFINITY)
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t = now(clock_boottime_or_monotonic());
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if (n->until > t)
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break;
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remove_one:
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lldp_neighbor_unlink(n);
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lldp_callback(lldp, SD_LLDP_EVENT_REMOVED, n);
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changed = true;
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}
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return changed;
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}
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static bool lldp_keep_neighbor(sd_lldp *lldp, sd_lldp_neighbor *n) {
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assert(lldp);
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assert(n);
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/* Don't keep data with a zero TTL */
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if (n->ttl <= 0)
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return false;
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/* Filter out data from the filter address */
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if (!ether_addr_is_null(&lldp->filter_address) &&
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ether_addr_equal(&lldp->filter_address, &n->source_address))
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return false;
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/* Only add if the neighbor has a capability we are interested in. Note that we also store all neighbors with
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* no caps field set. */
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if (n->has_capabilities &&
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(n->enabled_capabilities & lldp->capability_mask) == 0)
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return false;
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/* Keep everything else */
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return true;
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}
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static int lldp_start_timer(sd_lldp *lldp, sd_lldp_neighbor *neighbor);
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static int lldp_add_neighbor(sd_lldp *lldp, sd_lldp_neighbor *n) {
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_cleanup_(sd_lldp_neighbor_unrefp) sd_lldp_neighbor *old = NULL;
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bool keep;
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int r;
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assert(lldp);
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assert(n);
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assert(!n->lldp);
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keep = lldp_keep_neighbor(lldp, n);
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/* First retrieve the old entry for this MSAP */
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old = hashmap_get(lldp->neighbor_by_id, &n->id);
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if (old) {
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sd_lldp_neighbor_ref(old);
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if (!keep) {
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lldp_neighbor_unlink(old);
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lldp_callback(lldp, SD_LLDP_EVENT_REMOVED, old);
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return 0;
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}
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if (lldp_neighbor_equal(n, old)) {
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/* Is this equal, then restart the TTL counter, but don't do anyting else. */
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old->timestamp = n->timestamp;
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lldp_start_timer(lldp, old);
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lldp_callback(lldp, SD_LLDP_EVENT_REFRESHED, old);
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return 0;
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}
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/* Data changed, remove the old entry, and add a new one */
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lldp_neighbor_unlink(old);
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} else if (!keep)
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return 0;
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/* Then, make room for at least one new neighbor */
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lldp_make_space(lldp, 1);
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r = hashmap_put(lldp->neighbor_by_id, &n->id, n);
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if (r < 0)
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goto finish;
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r = prioq_put(lldp->neighbor_by_expiry, n, &n->prioq_idx);
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if (r < 0) {
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assert_se(hashmap_remove(lldp->neighbor_by_id, &n->id) == n);
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goto finish;
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}
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n->lldp = lldp;
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lldp_start_timer(lldp, n);
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lldp_callback(lldp, old ? SD_LLDP_EVENT_UPDATED : SD_LLDP_EVENT_ADDED, n);
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return 1;
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finish:
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if (old)
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lldp_callback(lldp, SD_LLDP_EVENT_REMOVED, old);
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return r;
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}
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static int lldp_handle_datagram(sd_lldp *lldp, sd_lldp_neighbor *n) {
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int r;
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assert(lldp);
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assert(n);
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r = lldp_neighbor_parse(n);
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if (r == -EBADMSG) /* Ignore bad messages */
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return 0;
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if (r < 0)
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return r;
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r = lldp_add_neighbor(lldp, n);
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if (r < 0) {
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log_lldp_errno(r, "Failed to add datagram. Ignoring.");
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return 0;
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}
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log_lldp("Successfully processed LLDP datagram.");
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return 0;
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}
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static int lldp_receive_datagram(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
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_cleanup_(sd_lldp_neighbor_unrefp) sd_lldp_neighbor *n = NULL;
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ssize_t space, length;
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sd_lldp *lldp = userdata;
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struct timespec ts;
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assert(fd >= 0);
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assert(lldp);
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space = next_datagram_size_fd(fd);
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if (space < 0)
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return log_lldp_errno(space, "Failed to determine datagram size to read: %m");
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n = lldp_neighbor_new(space);
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if (!n)
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return -ENOMEM;
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length = recv(fd, LLDP_NEIGHBOR_RAW(n), n->raw_size, MSG_DONTWAIT);
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if (length < 0) {
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if (errno == EAGAIN || errno == EINTR)
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return 0;
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return log_lldp_errno(errno, "Failed to read LLDP datagram: %m");
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}
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if ((size_t) length != n->raw_size) {
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log_lldp("Packet size mismatch.");
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return -EINVAL;
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}
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/* Try to get the timestamp of this packet if it is known */
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if (ioctl(fd, SIOCGSTAMPNS, &ts) >= 0)
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triple_timestamp_from_realtime(&n->timestamp, timespec_load(&ts));
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else
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triple_timestamp_get(&n->timestamp);
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return lldp_handle_datagram(lldp, n);
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}
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static void lldp_reset(sd_lldp *lldp) {
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assert(lldp);
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lldp->timer_event_source = sd_event_source_unref(lldp->timer_event_source);
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lldp->io_event_source = sd_event_source_unref(lldp->io_event_source);
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lldp->fd = safe_close(lldp->fd);
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}
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_public_ int sd_lldp_start(sd_lldp *lldp) {
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int r;
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assert_return(lldp, -EINVAL);
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assert_return(lldp->event, -EINVAL);
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assert_return(lldp->ifindex > 0, -EINVAL);
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if (lldp->fd >= 0)
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return 0;
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assert(!lldp->io_event_source);
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lldp->fd = lldp_network_bind_raw_socket(lldp->ifindex);
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if (lldp->fd < 0)
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return lldp->fd;
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r = sd_event_add_io(lldp->event, &lldp->io_event_source, lldp->fd, EPOLLIN, lldp_receive_datagram, lldp);
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if (r < 0)
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goto fail;
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r = sd_event_source_set_priority(lldp->io_event_source, lldp->event_priority);
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if (r < 0)
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goto fail;
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(void) sd_event_source_set_description(lldp->io_event_source, "lldp-io");
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log_lldp("Started LLDP client");
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return 1;
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fail:
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lldp_reset(lldp);
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return r;
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}
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_public_ int sd_lldp_stop(sd_lldp *lldp) {
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assert_return(lldp, -EINVAL);
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if (lldp->fd < 0)
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return 0;
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log_lldp("Stopping LLDP client");
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lldp_reset(lldp);
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lldp_flush_neighbors(lldp);
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return 1;
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}
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_public_ int sd_lldp_attach_event(sd_lldp *lldp, sd_event *event, int64_t priority) {
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int r;
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assert_return(lldp, -EINVAL);
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assert_return(lldp->fd < 0, -EBUSY);
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assert_return(!lldp->event, -EBUSY);
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if (event)
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lldp->event = sd_event_ref(event);
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else {
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r = sd_event_default(&lldp->event);
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if (r < 0)
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return r;
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}
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lldp->event_priority = priority;
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return 0;
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}
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_public_ int sd_lldp_detach_event(sd_lldp *lldp) {
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assert_return(lldp, -EINVAL);
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assert_return(lldp->fd < 0, -EBUSY);
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lldp->event = sd_event_unref(lldp->event);
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return 0;
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}
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_public_ sd_event* sd_lldp_get_event(sd_lldp *lldp) {
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assert_return(lldp, NULL);
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return lldp->event;
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}
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_public_ int sd_lldp_set_callback(sd_lldp *lldp, sd_lldp_callback_t cb, void *userdata) {
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assert_return(lldp, -EINVAL);
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lldp->callback = cb;
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lldp->userdata = userdata;
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return 0;
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}
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_public_ int sd_lldp_set_ifindex(sd_lldp *lldp, int ifindex) {
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assert_return(lldp, -EINVAL);
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assert_return(ifindex > 0, -EINVAL);
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assert_return(lldp->fd < 0, -EBUSY);
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lldp->ifindex = ifindex;
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return 0;
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}
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_public_ sd_lldp* sd_lldp_ref(sd_lldp *lldp) {
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if (!lldp)
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return NULL;
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assert(lldp->n_ref > 0);
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lldp->n_ref++;
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return lldp;
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}
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_public_ sd_lldp* sd_lldp_unref(sd_lldp *lldp) {
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if (!lldp)
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return NULL;
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assert(lldp->n_ref > 0);
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lldp->n_ref --;
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if (lldp->n_ref > 0)
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return NULL;
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lldp_reset(lldp);
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sd_lldp_detach_event(lldp);
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lldp_flush_neighbors(lldp);
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hashmap_free(lldp->neighbor_by_id);
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prioq_free(lldp->neighbor_by_expiry);
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return mfree(lldp);
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}
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_public_ int sd_lldp_new(sd_lldp **ret) {
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_cleanup_(sd_lldp_unrefp) sd_lldp *lldp = NULL;
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int r;
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assert_return(ret, -EINVAL);
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lldp = new0(sd_lldp, 1);
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if (!lldp)
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return -ENOMEM;
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lldp->n_ref = 1;
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lldp->fd = -1;
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lldp->neighbors_max = LLDP_DEFAULT_NEIGHBORS_MAX;
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lldp->capability_mask = (uint16_t) -1;
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lldp->neighbor_by_id = hashmap_new(&lldp_neighbor_id_hash_ops);
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if (!lldp->neighbor_by_id)
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return -ENOMEM;
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r = prioq_ensure_allocated(&lldp->neighbor_by_expiry, lldp_neighbor_prioq_compare_func);
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if (r < 0)
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return r;
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*ret = lldp;
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lldp = NULL;
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return 0;
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}
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static int neighbor_compare_func(const void *a, const void *b) {
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const sd_lldp_neighbor * const*x = a, * const *y = b;
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return lldp_neighbor_id_hash_ops.compare(&(*x)->id, &(*y)->id);
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}
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static int on_timer_event(sd_event_source *s, uint64_t usec, void *userdata) {
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sd_lldp *lldp = userdata;
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int r, q;
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r = lldp_make_space(lldp, 0);
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if (r < 0)
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return log_lldp_errno(r, "Failed to make space: %m");
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q = lldp_start_timer(lldp, NULL);
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if (q < 0)
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return log_lldp_errno(q, "Failed to restart timer: %m");
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return 0;
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}
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static int lldp_start_timer(sd_lldp *lldp, sd_lldp_neighbor *neighbor) {
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sd_lldp_neighbor *n;
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int r;
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assert(lldp);
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if (neighbor)
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lldp_neighbor_start_ttl(neighbor);
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n = prioq_peek(lldp->neighbor_by_expiry);
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if (!n) {
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if (lldp->timer_event_source)
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return sd_event_source_set_enabled(lldp->timer_event_source, SD_EVENT_OFF);
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return 0;
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}
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if (lldp->timer_event_source) {
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r = sd_event_source_set_time(lldp->timer_event_source, n->until);
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if (r < 0)
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return r;
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return sd_event_source_set_enabled(lldp->timer_event_source, SD_EVENT_ONESHOT);
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}
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if (!lldp->event)
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return 0;
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r = sd_event_add_time(lldp->event, &lldp->timer_event_source, clock_boottime_or_monotonic(), n->until, 0, on_timer_event, lldp);
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if (r < 0)
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return r;
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r = sd_event_source_set_priority(lldp->timer_event_source, lldp->event_priority);
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if (r < 0)
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return r;
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(void) sd_event_source_set_description(lldp->timer_event_source, "lldp-timer");
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return 0;
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}
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_public_ int sd_lldp_get_neighbors(sd_lldp *lldp, sd_lldp_neighbor ***ret) {
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sd_lldp_neighbor **l = NULL, *n;
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Iterator i;
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int k = 0, r;
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assert_return(lldp, -EINVAL);
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assert_return(ret, -EINVAL);
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if (hashmap_isempty(lldp->neighbor_by_id)) { /* Special shortcut */
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*ret = NULL;
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return 0;
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}
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l = new0(sd_lldp_neighbor*, hashmap_size(lldp->neighbor_by_id));
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if (!l)
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return -ENOMEM;
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r = lldp_start_timer(lldp, NULL);
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if (r < 0) {
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free(l);
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return r;
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}
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HASHMAP_FOREACH(n, lldp->neighbor_by_id, i)
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l[k++] = sd_lldp_neighbor_ref(n);
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assert((size_t) k == hashmap_size(lldp->neighbor_by_id));
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/* Return things in a stable order */
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qsort(l, k, sizeof(sd_lldp_neighbor*), neighbor_compare_func);
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*ret = l;
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return k;
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}
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_public_ int sd_lldp_set_neighbors_max(sd_lldp *lldp, uint64_t m) {
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assert_return(lldp, -EINVAL);
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assert_return(m <= 0, -EINVAL);
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lldp->neighbors_max = m;
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lldp_make_space(lldp, 0);
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return 0;
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}
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_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;
|
|
}
|