Merge pull request #2685 from poettering/lldp-fixes2

lldp fixes, second iteration

1 files changed, 347 insertions, 0 deletions

diff --git a/src/network/networkd-lldp-tx.c b/src/network/networkd-lldp-tx.c
new file mode 100644
index 0000000000..ae8367a60e
--- /dev/null
+++ b/src/network/networkd-lldp-tx.c
@@ -0,0 +1,347 @@
+/***
+  This file is part of systemd.
+
+  Copyright 2016 Lennart Poettering
+
+  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 <endian.h>
+#include <inttypes.h>
+#include <string.h>
+
+#include "fd-util.h"
+#include "fileio.h"
+#include "hostname-util.h"
+#include "lldp.h"
+#include "networkd-lldp-tx.h"
+#include "random-util.h"
+#include "socket-util.h"
+#include "string-util.h"
+#include "unaligned.h"
+
+/* The LLDP spec calls this "txFastInit", see 9.2.5.19 */
+#define LLDP_TX_FAST_INIT 4U
+
+/* The LLDP spec calls this "msgTxHold", see 9.2.5.6 */
+#define LLDP_TX_HOLD 4U
+
+/* The jitter range to add, see 9.2.2. */
+#define LLDP_JITTER_USEC (400U * USEC_PER_MSEC)
+
+/* The LLDP spec calls this msgTxInterval, but we subtract half the jitter off it. */
+#define LLDP_TX_INTERVAL_USEC (30U * USEC_PER_SEC - LLDP_JITTER_USEC / 2)
+
+/* The LLDP spec calls this msgFastTx, but we subtract half the jitter off it. */
+#define LLDP_FAST_TX_USEC (1U * USEC_PER_SEC - LLDP_JITTER_USEC / 2)
+
+static int lldp_write_tlv_header(uint8_t **p, uint8_t id, size_t sz) {
+        assert(p);
+
+        if (id > 127)
+                return -EBADMSG;
+        if (sz > 511)
+                return -ENOBUFS;
+
+        (*p)[0] = (id << 1) | !!(sz & 256);
+        (*p)[1] = sz & 255;
+
+        *p = *p + 2;
+        return 0;
+}
+
+static int lldp_make_packet(
+                const struct ether_addr *hwaddr,
+                const char *machine_id,
+                const char *ifname,
+                uint16_t ttl,
+                const char *port_description,
+                const char *hostname,
+                const char *pretty_hostname,
+                uint16_t system_capabilities,
+                uint16_t enabled_capabilities,
+                void **ret, size_t *sz) {
+
+        size_t machine_id_length, ifname_length, port_description_length = 0, hostname_length = 0, pretty_hostname_length = 0;
+        _cleanup_free_ void *packet = NULL;
+        struct ether_header *h;
+        uint8_t *p;
+        size_t l;
+        int r;
+
+        assert(hwaddr);
+        assert(machine_id);
+        assert(ifname);
+        assert(ret);
+        assert(sz);
+
+        machine_id_length = strlen(machine_id);
+        ifname_length = strlen(ifname);
+
+        if (port_description)
+                port_description_length = strlen(port_description);
+
+        if (hostname)
+                hostname_length = strlen(hostname);
+
+        if (pretty_hostname)
+                pretty_hostname_length = strlen(pretty_hostname);
+
+        l = sizeof(struct ether_header) +
+                /* Chassis ID */
+                2 + 1 + machine_id_length +
+                /* Port ID */
+                2 + 1 + ifname_length +
+                /* TTL */
+                2 + 2 +
+                /* System Capabilities */
+                2 + 4 +
+                /* End */
+                2;
+
+        /* Port Description */
+        if (port_description)
+                l += 2 + port_description_length;
+
+        /* System Name */
+        if (hostname)
+                l += 2 + hostname_length;
+
+        /* System Description */
+        if (pretty_hostname)
+                l += 2 + pretty_hostname_length;
+
+        packet = malloc(l);
+        if (!packet)
+                return -ENOMEM;
+
+        h = (struct ether_header*) packet;
+        h->ether_type = htobe16(ETHERTYPE_LLDP);
+        memcpy(h->ether_dhost, &(struct ether_addr) { LLDP_MULTICAST_ADDR }, ETH_ALEN);
+        memcpy(h->ether_shost, hwaddr, ETH_ALEN);
+
+        p = (uint8_t*) packet + sizeof(struct ether_header);
+
+        r = lldp_write_tlv_header(&p, LLDP_TYPE_CHASSIS_ID, 1 + machine_id_length);
+        if (r < 0)
+                return r;
+        *(p++) = LLDP_CHASSIS_SUBTYPE_LOCALLY_ASSIGNED;
+        p = mempcpy(p, machine_id, machine_id_length);
+
+        r = lldp_write_tlv_header(&p, LLDP_TYPE_PORT_ID, 1 + ifname_length);
+        if (r < 0)
+                return r;
+        *(p++) = LLDP_PORT_SUBTYPE_INTERFACE_NAME;
+        p = mempcpy(p, ifname, ifname_length);
+
+        r = lldp_write_tlv_header(&p, LLDP_TYPE_TTL, 2);
+        if (r < 0)
+                return r;
+        unaligned_write_be16(p, ttl);
+        p += 2;
+
+        if (port_description) {
+                r = lldp_write_tlv_header(&p, LLDP_TYPE_PORT_DESCRIPTION, port_description_length);
+                if (r < 0)
+                        return r;
+                p = mempcpy(p, port_description, port_description_length);
+        }
+
+        if (hostname) {
+                r = lldp_write_tlv_header(&p, LLDP_TYPE_SYSTEM_NAME, hostname_length);
+                if (r < 0)
+                        return r;
+                p = mempcpy(p, hostname, hostname_length);
+        }
+
+        if (pretty_hostname) {
+                r = lldp_write_tlv_header(&p, LLDP_TYPE_SYSTEM_DESCRIPTION, pretty_hostname_length);
+                if (r < 0)
+                        return r;
+                p = mempcpy(p, pretty_hostname, pretty_hostname_length);
+        }
+
+        r = lldp_write_tlv_header(&p, LLDP_TYPE_SYSTEM_CAPABILITIES, 4);
+        if (r < 0)
+                return r;
+        unaligned_write_be16(p, system_capabilities);
+        p += 2;
+        unaligned_write_be16(p, enabled_capabilities);
+        p += 2;
+
+        r = lldp_write_tlv_header(&p, LLDP_TYPE_END, 0);
+        if (r < 0)
+                return r;
+
+        assert(p == (uint8_t*) packet + l);
+
+        *ret = packet;
+        *sz = l;
+
+        packet = NULL;
+        return 0;
+}
+
+static int lldp_send_packet(int ifindex, const void *packet, size_t packet_size) {
+
+        union sockaddr_union sa = {
+                .ll.sll_family = AF_PACKET,
+                .ll.sll_protocol = htobe16(ETHERTYPE_LLDP),
+                .ll.sll_ifindex = ifindex,
+                .ll.sll_halen = ETH_ALEN,
+                .ll.sll_addr = LLDP_MULTICAST_ADDR,
+        };
+
+        _cleanup_close_ int fd = -1;
+        ssize_t l;
+
+        assert(ifindex > 0);
+        assert(packet || packet_size <= 0);
+
+        fd = socket(PF_PACKET, SOCK_RAW|SOCK_CLOEXEC, IPPROTO_RAW);
+        if (fd < 0)
+                return -errno;
+
+        l = sendto(fd, packet, packet_size, MSG_NOSIGNAL, &sa.sa, sizeof(sa.ll));
+        if (l < 0)
+                return -errno;
+
+        if ((size_t) l != packet_size)
+                return -EIO;
+
+        return 0;
+}
+
+static int link_send_lldp(Link *link) {
+        char machine_id_string[SD_ID128_STRING_MAX];
+        _cleanup_free_ char *hostname = NULL, *pretty_hostname = NULL;
+        _cleanup_free_ void *packet = NULL;
+        size_t packet_size = 0;
+        sd_id128_t machine_id;
+        uint16_t caps;
+        usec_t ttl;
+        int r;
+
+        r = sd_id128_get_machine(&machine_id);
+        if (r < 0)
+                return r;
+
+        (void) gethostname_strict(&hostname);
+        (void) parse_env_file("/etc/machine-info", NEWLINE, "PRETTY_HOSTNAME", &pretty_hostname, NULL);
+
+        ttl = DIV_ROUND_UP(LLDP_TX_INTERVAL_USEC * LLDP_TX_HOLD + 1, USEC_PER_SEC);
+        if (ttl > (usec_t) UINT16_MAX)
+                ttl = (usec_t) UINT16_MAX;
+
+        caps = (link->network && link->network->ip_forward != ADDRESS_FAMILY_NO) ?
+                LLDP_SYSTEM_CAPABILITIES_ROUTER :
+                LLDP_SYSTEM_CAPABILITIES_STATION;
+
+        r = lldp_make_packet(&link->mac,
+                             sd_id128_to_string(machine_id, machine_id_string),
+                             link->ifname,
+                             (uint16_t) ttl,
+                             link->network ? link->network->description : NULL,
+                             hostname,
+                             pretty_hostname,
+                             LLDP_SYSTEM_CAPABILITIES_STATION|LLDP_SYSTEM_CAPABILITIES_BRIDGE|LLDP_SYSTEM_CAPABILITIES_ROUTER,
+                             caps,
+                             &packet, &packet_size);
+        if (r < 0)
+                return r;
+
+        return lldp_send_packet(link->ifindex, packet, packet_size);
+}
+
+static int on_lldp_timer(sd_event_source *s, usec_t t, void *userdata) {
+        Link *link = userdata;
+        usec_t current, delay, next;
+        int r;
+
+        assert(s);
+        assert(userdata);
+
+        log_link_debug(link, "Sending LLDP packet...");
+
+        r = link_send_lldp(link);
+        if (r < 0)
+                log_link_debug_errno(link, r, "Failed to send LLDP packet, ignoring: %m");
+
+        if (link->lldp_tx_fast > 0)
+                link->lldp_tx_fast--;
+
+        assert_se(sd_event_now(sd_event_source_get_event(s), clock_boottime_or_monotonic(), &current) >= 0);
+
+        delay = link->lldp_tx_fast > 0 ? LLDP_FAST_TX_USEC : LLDP_TX_INTERVAL_USEC;
+        next = usec_add(usec_add(current, delay), (usec_t) random_u64() % LLDP_JITTER_USEC);
+
+        r = sd_event_source_set_time(s, next);
+        if (r < 0)
+                return log_link_error_errno(link, r, "Failed to restart LLDP timer: %m");
+
+        r = sd_event_source_set_enabled(s, SD_EVENT_ONESHOT);
+        if (r < 0)
+                return log_link_error_errno(link, r, "Failed to enable LLDP timer: %m");
+
+        return 0;
+}
+
+int link_lldp_tx_start(Link *link) {
+        usec_t next;
+        int r;
+
+        assert(link);
+
+        /* Starts the LLDP transmission in "fast" mode. If it is already started, turns "fast" mode back on again. */
+
+        link->lldp_tx_fast = LLDP_TX_FAST_INIT;
+
+        next = usec_add(usec_add(now(clock_boottime_or_monotonic()), LLDP_FAST_TX_USEC),
+                     (usec_t) random_u64() % LLDP_JITTER_USEC);
+
+        if (link->lldp_tx_event_source) {
+                usec_t old;
+
+                /* Lower the timeout, maybe */
+                r = sd_event_source_get_time(link->lldp_tx_event_source, &old);
+                if (r < 0)
+                        return r;
+
+                if (old <= next)
+                        return 0;
+
+                return sd_event_source_set_time(link->lldp_tx_event_source, next);
+        } else {
+                r = sd_event_add_time(
+                                link->manager->event,
+                                &link->lldp_tx_event_source,
+                                clock_boottime_or_monotonic(),
+                                next,
+                                0,
+                                on_lldp_timer,
+                                link);
+                if (r < 0)
+                        return r;
+
+                (void) sd_event_source_set_description(link->lldp_tx_event_source, "lldp-tx");
+        }
+
+        return 0;
+}
+
+void link_lldp_tx_stop(Link *link) {
+        assert(link);
+
+        link->lldp_tx_event_source = sd_event_source_unref(link->lldp_tx_event_source);
+}