/***
This file is part of systemd.
Copyright (C) 2014 Tom Gundersen
Copyright (C) 2014 Susant Sahani
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see .
***/
#include
#include
#include "basic/alloc-util.h"
#include "basic/fd-util.h"
#include "lldp-internal.h"
#include "lldp-neighbor.h"
#include "lldp-network.h"
#include "basic/socket-util.h"
#include "basic/ether-addr-util.h"
#define LLDP_DEFAULT_NEIGHBORS_MAX 128U
static void lldp_flush_neighbors(sd_lldp *lldp) {
sd_lldp_neighbor *n;
assert(lldp);
while ((n = hashmap_first(lldp->neighbor_by_id)))
lldp_neighbor_unlink(n);
}
static void lldp_callback(sd_lldp *lldp, sd_lldp_event event, sd_lldp_neighbor *n) {
assert(lldp);
assert(n);
log_lldp("Invoking callback for '%c'.", event);
if (!lldp->callback)
return;
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 anyting else. */
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, n);
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;
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)
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;
}
return lldp_handle_datagram(lldp, n);
}
_public_ int sd_lldp_start(sd_lldp *lldp) {
int r;
assert_return(lldp, -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;
if (lldp->event) {
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");
}
return 1;
fail:
lldp->io_event_source = sd_event_source_unref(lldp->io_event_source);
lldp->fd = safe_close(lldp->fd);
return r;
}
_public_ int sd_lldp_stop(sd_lldp *lldp) {
assert_return(lldp, -EINVAL);
if (lldp->fd < 0)
return 0;
lldp->timer_event_source = sd_event_source_unref(lldp->timer_event_source);
lldp->io_event_source = sd_event_source_unref(lldp->io_event_source);
lldp->fd = safe_close(lldp->fd);
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_ 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_ sd_lldp* sd_lldp_unref(sd_lldp *lldp) {
if (!lldp)
return NULL;
lldp_flush_neighbors(lldp);
hashmap_free(lldp->neighbor_by_id);
prioq_free(lldp->neighbor_by_expiry);
sd_event_source_unref(lldp->io_event_source);
sd_event_source_unref(lldp->timer_event_source);
sd_event_unref(lldp->event);
safe_close(lldp->fd);
free(lldp);
return NULL;
}
_public_ int sd_lldp_new(sd_lldp **ret, int ifindex) {
_cleanup_(sd_lldp_unrefp) sd_lldp *lldp = NULL;
int r;
assert_return(ret, -EINVAL);
assert_return(ifindex > 0, -EINVAL);
lldp = new0(sd_lldp, 1);
if (!lldp)
return -ENOMEM;
lldp->fd = -1;
lldp->ifindex = ifindex;
lldp->neighbors_max = LLDP_DEFAULT_NEIGHBORS_MAX;
lldp->capability_mask = (uint16_t) -1;
lldp->neighbor_by_id = hashmap_new(&lldp_neighbor_id_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 = lldp;
lldp = NULL;
return 0;
}
static int neighbor_compare_func(const void *a, const void *b) {
const sd_lldp_neighbor * const*x = a, * const *y = b;
return lldp_neighbor_id_hash_ops.compare(&(*x)->id, &(*y)->id);
}
static int on_timer_event(sd_event_source *s, uint64_t usec, void *userdata) {
sd_lldp *lldp = userdata;
int r, q;
r = lldp_make_space(lldp, 0);
if (r < 0)
return log_lldp_errno(r, "Failed to make space: %m");
q = lldp_start_timer(lldp, NULL);
if (q < 0)
return log_lldp_errno(q, "Failed to restart timer: %m");
return 0;
}
static int lldp_start_timer(sd_lldp *lldp, sd_lldp_neighbor *neighbor) {
sd_lldp_neighbor *n;
int r;
assert(lldp);
if (neighbor)
lldp_neighbor_start_ttl(neighbor);
n = prioq_peek(lldp->neighbor_by_expiry);
if (!n) {
if (lldp->timer_event_source)
return sd_event_source_set_enabled(lldp->timer_event_source, SD_EVENT_OFF);
return 0;
}
if (lldp->timer_event_source) {
r = sd_event_source_set_time(lldp->timer_event_source, n->until);
if (r < 0)
return r;
return sd_event_source_set_enabled(lldp->timer_event_source, SD_EVENT_ONESHOT);
}
if (!lldp->event)
return 0;
r = sd_event_add_time(lldp->event, &lldp->timer_event_source, clock_boottime_or_monotonic(), n->until, 0, on_timer_event, lldp);
if (r < 0)
return r;
r = sd_event_source_set_priority(lldp->timer_event_source, lldp->event_priority);
if (r < 0)
return r;
(void) sd_event_source_set_description(lldp->timer_event_source, "lldp-timer");
return 0;
}
_public_ int sd_lldp_get_neighbors(sd_lldp *lldp, sd_lldp_neighbor ***ret) {
sd_lldp_neighbor **l = NULL, *n;
Iterator i;
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, i)
l[k++] = sd_lldp_neighbor_ref(n);
assert((size_t) k == hashmap_size(lldp->neighbor_by_id));
/* Return things in a stable order */
qsort(l, k, sizeof(sd_lldp_neighbor*), 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) {
zero(lldp->filter_address);
return 0;
}
lldp->filter_address = *addr;
return 0;
}