summaryrefslogtreecommitdiff
path: root/src/libsystemd-network/lldp-internal.c
diff options
context:
space:
mode:
authorSusant Sahani <susant@redhat.com>2014-11-23 09:46:36 +0530
committerSusant Sahani <susant@redhat.com>2014-12-19 08:02:45 +0530
commitad1ad5c8e36ea795034fcdac660b15d7c141d55b (patch)
tree6cbd058659041f88cce2d1f9617eb0aba5d6e449 /src/libsystemd-network/lldp-internal.c
parent266b538958932e6fc27dfce4917336e70e17e29e (diff)
networkd: Introduce Link Layer Discovery Protocol (LLDP)
This patch introduces LLDP support to networkd. it implements the receiver side of the protocol. The Link Layer Discovery Protocol (LLDP) is an industry-standard, vendor-neutral method to allow networked devices to advertise capabilities, identity, and other information onto a LAN. The Layer 2 protocol, detailed in IEEE 802.1AB-2005.LLDP allows network devices that operate at the lower layers of a protocol stack (such as Layer 2 bridges and switches) to learn some of the capabilities and characteristics of LAN devices available to higher layer protocols.
Diffstat (limited to 'src/libsystemd-network/lldp-internal.c')
-rw-r--r--src/libsystemd-network/lldp-internal.c437
1 files changed, 437 insertions, 0 deletions
diff --git a/src/libsystemd-network/lldp-internal.c b/src/libsystemd-network/lldp-internal.c
new file mode 100644
index 0000000000..7085a02491
--- /dev/null
+++ b/src/libsystemd-network/lldp-internal.c
@@ -0,0 +1,437 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ 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 <http://www.gnu.org/licenses/>.
+***/
+
+#include "lldp-internal.h"
+
+/* We store maximum 1K chassis entries */
+#define LLDP_MIB_MAX_CHASSIS 1024
+
+/* Maximum Ports can be attached to any chassis */
+#define LLDP_MIB_MAX_PORT_PER_CHASSIS 32
+
+int lldp_read_chassis_id(tlv_packet *tlv,
+ uint8_t *type,
+ uint16_t *length,
+ uint8_t **data) {
+ uint8_t subtype;
+ int r;
+
+ assert_return(tlv, -EINVAL);
+
+ r = lldp_tlv_packet_enter_container(tlv, LLDP_TYPE_CHASSIS_ID);
+ if (r < 0)
+ goto out2;
+
+ r = tlv_packet_read_u8(tlv, &subtype);
+ if (r < 0)
+ goto out1;
+
+ switch (subtype) {
+ case LLDP_CHASSIS_SUBTYPE_MAC_ADDRESS:
+
+ r = tlv_packet_read_bytes(tlv, data, length);
+ if (r < 0)
+ goto out1;
+
+ break;
+ default:
+ r = -ENOTSUP;
+ break;
+ }
+
+ *type = subtype;
+
+ out1:
+ (void)lldp_tlv_packet_exit_container(tlv);
+
+ out2:
+ return r;
+}
+
+int lldp_read_port_id(tlv_packet *tlv,
+ uint8_t *type,
+ uint16_t *length,
+ uint8_t **data) {
+ uint8_t subtype;
+ char *s;
+ int r;
+
+ assert_return(tlv, -EINVAL);
+
+ r = lldp_tlv_packet_enter_container(tlv, LLDP_TYPE_PORT_ID);
+ if (r < 0)
+ goto out2;
+
+ r = tlv_packet_read_u8(tlv, &subtype);
+ if (r < 0)
+ goto out1;
+
+ switch (subtype) {
+ case LLDP_PORT_SUBTYPE_INTERFACE_NAME:
+
+ r = tlv_packet_read_string(tlv, &s, length);
+ if (r < 0)
+ goto out1;
+
+ *data = (uint8_t *) s;
+
+ break;
+ case LLDP_PORT_SUBTYPE_MAC_ADDRESS:
+
+ r = tlv_packet_read_bytes(tlv, data, length);
+ if (r < 0)
+ goto out1;
+
+ break;
+ default:
+ r = -ENOTSUP;
+ break;
+ }
+
+ *type = subtype;
+
+ out1:
+ (void)lldp_tlv_packet_exit_container(tlv);
+
+ out2:
+ return r;
+}
+
+int lldp_read_ttl(tlv_packet *tlv, uint16_t *ttl) {
+ int r;
+
+ assert_return(tlv, -EINVAL);
+
+ r = lldp_tlv_packet_enter_container(tlv, LLDP_TYPE_TTL);
+ if (r < 0)
+ goto out;
+
+ r = tlv_packet_read_u16(tlv, ttl);
+
+ (void) lldp_tlv_packet_exit_container(tlv);
+
+ out:
+ return r;
+}
+
+/* 10.5.5.2.2 mibUpdateObjects ()
+ * The mibUpdateObjects () procedure updates the MIB objects corresponding to
+ * the TLVs contained in the received LLDPDU for the LLDP remote system
+ * indicated by the LLDP remote systems update process defined in 10.3.5 */
+
+int lldp_mib_update_objects(lldp_chassis *c, tlv_packet *tlv) {
+ lldp_neighbour_port *p;
+ uint16_t length, ttl;
+ uint8_t *data;
+ uint8_t type;
+ int r;
+
+ assert_return(c, -EINVAL);
+ assert_return(tlv, -EINVAL);
+
+ r = lldp_read_port_id(tlv, &type, &length, &data);
+ if (r < 0)
+ return r;
+
+ /* Update the packet if we already have */
+ LIST_FOREACH(port, p, c->ports) {
+
+ if ((p->type == type && p->length == length && !memcmp(p->data, data, p->length))) {
+
+ r = lldp_read_ttl(tlv, &ttl);
+ if (r < 0)
+ return r;
+
+ p->until = ttl * USEC_PER_SEC + now(clock_boottime_or_monotonic());
+
+ tlv_packet_free(p->packet);
+ p->packet = tlv;
+
+ prioq_reshuffle(p->c->by_expiry, p, &p->prioq_idx);
+
+ return 0;
+ }
+ }
+
+ return -1;
+}
+
+int lldp_mib_remove_objects(lldp_chassis *c, tlv_packet *tlv) {
+ lldp_neighbour_port *p, *q;
+ uint8_t *data;
+ uint16_t length;
+ uint8_t type;
+ int r;
+
+ assert_return(c, -EINVAL);
+ assert_return(tlv, -EINVAL);
+
+ r = lldp_read_port_id(tlv, &type, &length, &data);
+ if (r < 0)
+ return r;
+
+ LIST_FOREACH_SAFE(port, p, q, c->ports) {
+
+ /* Find the port */
+ if (p->type == type && p->length == length && !memcmp(p->data, data, p->length)) {
+ lldp_neighbour_port_remove_and_free(p);
+ break;
+ }
+ }
+
+ return 0;
+}
+
+int lldp_mib_add_objects(Prioq *by_expiry,
+ Hashmap *neighbour_mib,
+ tlv_packet *tlv) {
+ _cleanup_lldp_neighbour_port_free_ lldp_neighbour_port *p = NULL;
+ _cleanup_lldp_chassis_free_ lldp_chassis *c = NULL;
+ lldp_chassis_id chassis_id;
+ bool new_chassis = false;
+ uint8_t subtype, *data;
+ uint16_t ttl, length;
+ int r;
+
+ assert_return(by_expiry, -EINVAL);
+ assert_return(neighbour_mib, -EINVAL);
+ assert_return(tlv, -EINVAL);
+
+ r = lldp_read_chassis_id(tlv, &subtype, &length, &data);
+ if (r < 0)
+ goto drop;
+
+ r = lldp_read_ttl(tlv, &ttl);
+ if (r < 0)
+ goto drop;
+
+ /* Make hash key */
+ chassis_id.type = subtype;
+ chassis_id.length = length;
+ chassis_id.data = data;
+
+ /* Try to find the Chassis */
+ c = hashmap_get(neighbour_mib, &chassis_id);
+ if (!c) {
+
+ /* Don't create chassis if ttl 0 is received . Silently drop it */
+ if (ttl == 0) {
+ log_lldp("TTL value 0 received. Skiping Chassis creation.");
+ goto drop;
+ }
+
+ /* Admission Control: Can we store this packet ? */
+ if (hashmap_size(neighbour_mib) >= LLDP_MIB_MAX_CHASSIS) {
+
+ log_lldp("Exceeding number of chassie: %d. Dropping ...",
+ hashmap_size(neighbour_mib));
+ goto drop;
+ }
+
+ r = lldp_chassis_new(tlv, by_expiry, neighbour_mib, &c);
+ if (r < 0)
+ goto drop;
+
+ new_chassis = true;
+
+ r = hashmap_put(neighbour_mib, &c->chassis_id, c);
+ if (r < 0)
+ goto drop;
+
+ } else {
+
+ /* When the TTL field is set to zero, the receiving LLDP agent is notified all
+ * system information associated with the LLDP agent/port is to be deleted */
+ if (ttl == 0) {
+ log_lldp("TTL value 0 received . Deleting associated Port ...");
+
+ lldp_mib_remove_objects(c, tlv);
+
+ c = NULL;
+ goto drop;
+ }
+
+ /* if we already have this port just update it */
+ r = lldp_mib_update_objects(c, tlv);
+ if (r >= 0) {
+ c = NULL;
+ return r;
+ }
+
+ /* Admission Control: Can this port attached to the existing chassis ? */
+ if (REFCNT_GET(c->n_ref) >= LLDP_MIB_MAX_PORT_PER_CHASSIS) {
+ log_lldp("Port limit reached. Chassis has: %d ports. Dropping ...",
+ REFCNT_GET(c->n_ref));
+
+ c = NULL;
+ goto drop;
+ }
+ }
+
+ /* This is a new port */
+ r = lldp_neighbour_port_new(c, tlv, &p);
+ if (r < 0)
+ goto drop;
+
+ r = prioq_put(c->by_expiry, p, &p->prioq_idx);
+ if (r < 0)
+ goto drop;
+
+ /* Attach new port to chassis */
+ LIST_PREPEND(port, c->ports, p);
+ REFCNT_INC(c->n_ref);
+
+ p = NULL;
+ c = NULL;
+
+ return 0;
+
+ drop:
+ tlv_packet_free(tlv);
+
+ if (new_chassis)
+ hashmap_remove(neighbour_mib, &c->chassis_id);
+
+ return r;
+}
+
+void lldp_neighbour_port_remove_and_free(lldp_neighbour_port *p) {
+ lldp_chassis *c;
+
+ assert(p);
+ assert(p->c);
+
+ c = p->c;
+
+ prioq_remove(c->by_expiry, p, &p->prioq_idx);
+
+ LIST_REMOVE(port, c->ports, p);
+ lldp_neighbour_port_free(p);
+
+ /* Drop the Chassis if no port is attached */
+ if (REFCNT_DEC(c->n_ref) <= 1) {
+ hashmap_remove(c->neighbour_mib, &c->chassis_id);
+ lldp_chassis_free(c);
+ }
+}
+
+void lldp_neighbour_port_free(lldp_neighbour_port *p) {
+
+ if(!p)
+ return;
+
+ tlv_packet_free(p->packet);
+
+ free(p->data);
+ free(p);
+}
+
+int lldp_neighbour_port_new(lldp_chassis *c,
+ tlv_packet *tlv,
+ lldp_neighbour_port **ret) {
+ _cleanup_lldp_neighbour_port_free_ lldp_neighbour_port *p;
+ uint16_t length, ttl;
+ uint8_t *data;
+ uint8_t type;
+ int r;
+
+ assert(tlv);
+
+ r = lldp_read_port_id(tlv, &type, &length, &data);
+ if (r < 0)
+ return r;
+
+ r = lldp_read_ttl(tlv, &ttl);
+ if (r < 0)
+ return r;
+
+ p = new0(lldp_neighbour_port, 1);
+ if (!p)
+ return -ENOMEM;
+
+ p->c = c;
+ p->type = type;
+ p->length = length;
+ p->packet = tlv;
+ p->prioq_idx = PRIOQ_IDX_NULL;
+ p->until = ttl * USEC_PER_SEC + now(clock_boottime_or_monotonic());
+
+ p->data = memdup(data, length);
+ if (!p->data)
+ return -ENOMEM;
+
+ *ret = p;
+ p = NULL;
+
+ return 0;
+}
+
+void lldp_chassis_free(lldp_chassis *c) {
+
+ if (!c)
+ return;
+
+ if (REFCNT_GET(c->n_ref) > 1)
+ return;
+
+ free(c->chassis_id.data);
+ free(c);
+}
+
+int lldp_chassis_new(tlv_packet *tlv,
+ Prioq *by_expiry,
+ Hashmap *neighbour_mib,
+ lldp_chassis **ret) {
+ _cleanup_lldp_chassis_free_ lldp_chassis *c;
+ uint16_t length;
+ uint8_t *data;
+ uint8_t type;
+ int r;
+
+ assert(tlv);
+
+ r = lldp_read_chassis_id(tlv, &type, &length, &data);
+ if (r < 0)
+ return r;
+
+ c = new0(lldp_chassis, 1);
+ if (!c)
+ return -ENOMEM;
+
+ c->n_ref = REFCNT_INIT;
+ c->chassis_id.type = type;
+ c->chassis_id.length = length;
+
+ c->chassis_id.data = memdup(data, length);
+ if (!c->chassis_id.data)
+ return -ENOMEM;
+
+ LIST_HEAD_INIT(c->ports);
+
+ c->by_expiry = by_expiry;
+ c->neighbour_mib = neighbour_mib;
+
+ *ret = c;
+ c = NULL;
+
+ return 0;
+}