/*** 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 . ***/ #include #include #include #include "fd-util.h" #include "fileio.h" #include "hostname-util.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) { SD_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, SD_LLDP_TYPE_CHASSIS_ID, 1 + machine_id_length); if (r < 0) return r; *(p++) = SD_LLDP_CHASSIS_SUBTYPE_LOCALLY_ASSIGNED; p = mempcpy(p, machine_id, machine_id_length); r = lldp_write_tlv_header(&p, SD_LLDP_TYPE_PORT_ID, 1 + ifname_length); if (r < 0) return r; *(p++) = SD_LLDP_PORT_SUBTYPE_INTERFACE_NAME; p = mempcpy(p, ifname, ifname_length); r = lldp_write_tlv_header(&p, SD_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, SD_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, SD_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, SD_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, SD_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, SD_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 = SD_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); assert_cc(LLDP_TX_INTERVAL_USEC * LLDP_TX_HOLD + 1 <= (UINT16_MAX - 1) * USEC_PER_SEC); ttl = DIV_ROUND_UP(LLDP_TX_INTERVAL_USEC * LLDP_TX_HOLD + 1, USEC_PER_SEC); caps = (link->network && link->network->ip_forward != ADDRESS_FAMILY_NO) ? SD_LLDP_SYSTEM_CAPABILITIES_ROUTER : SD_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, SD_LLDP_SYSTEM_CAPABILITIES_STATION|SD_LLDP_SYSTEM_CAPABILITIES_BRIDGE|SD_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(), ¤t) >= 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); }