diff options
Diffstat (limited to 'src/network/networkd-lldp-tx.c')
| -rw-r--r-- | src/network/networkd-lldp-tx.c | 399 |
1 files changed, 399 insertions, 0 deletions
diff --git a/src/network/networkd-lldp-tx.c b/src/network/networkd-lldp-tx.c new file mode 100644 index 0000000..8fd6365 --- /dev/null +++ b/src/network/networkd-lldp-tx.c @@ -0,0 +1,399 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <endian.h> +#include <inttypes.h> +#include <string.h> + +#include "alloc-util.h" +#include "env-file.h" +#include "fd-util.h" +#include "hostname-util.h" +#include "missing_network.h" +#include "networkd-lldp-tx.h" +#include "networkd-manager.h" +#include "parse-util.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 const struct ether_addr lldp_multicast_addr[_LLDP_EMIT_MAX] = { + [LLDP_EMIT_NEAREST_BRIDGE] = {{ 0x01, 0x80, 0xc2, 0x00, 0x00, 0x0e }}, + [LLDP_EMIT_NON_TPMR_BRIDGE] = {{ 0x01, 0x80, 0xc2, 0x00, 0x00, 0x03 }}, + [LLDP_EMIT_CUSTOMER_BRIDGE] = {{ 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 }}, +}; + +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( + LLDPEmit mode, + 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(mode > LLDP_EMIT_NO); + assert(mode < _LLDP_EMIT_MAX); + 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, lldp_multicast_addr + mode, 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 = TAKE_PTR(packet); + *sz = l; + + return 0; +} + +static int lldp_send_packet( + int ifindex, + const struct ether_addr *address, + 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, + }; + + _cleanup_close_ int fd = -1; + ssize_t l; + + assert(ifindex > 0); + assert(address); + assert(packet || packet_size <= 0); + + memcpy(sa.ll.sll_addr, address, ETH_ALEN); + + 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; + + assert(link); + + if (!link->network || link->network->lldp_emit == LLDP_EMIT_NO) + return 0; + + assert(link->network->lldp_emit < _LLDP_EMIT_MAX); + + r = sd_id128_get_machine(&machine_id); + if (r < 0) + return r; + + (void) gethostname_strict(&hostname); + (void) parse_env_file(NULL, "/etc/machine-info", "PRETTY_HOSTNAME", &pretty_hostname); + + 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->network->lldp_emit, + &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, lldp_multicast_addr + link->network->lldp_emit, 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_emit_start(Link *link) { + usec_t next; + int r; + + assert(link); + + if (!link->network || link->network->lldp_emit == LLDP_EMIT_NO) { + link_lldp_emit_stop(link); + return 0; + } + + /* 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_emit_event_source) { + usec_t old; + + /* Lower the timeout, maybe */ + r = sd_event_source_get_time(link->lldp_emit_event_source, &old); + if (r < 0) + return r; + + if (old <= next) + return 0; + + return sd_event_source_set_time(link->lldp_emit_event_source, next); + } else { + r = sd_event_add_time( + link->manager->event, + &link->lldp_emit_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_emit_event_source, "lldp-tx"); + } + + return 0; +} + +void link_lldp_emit_stop(Link *link) { + assert(link); + + link->lldp_emit_event_source = sd_event_source_unref(link->lldp_emit_event_source); +} + +int config_parse_lldp_emit( + const char *unit, + const char *filename, + unsigned line, + const char *section, + unsigned section_line, + const char *lvalue, + int ltype, + const char *rvalue, + void *data, + void *userdata) { + + LLDPEmit *emit = data; + int r; + + assert(filename); + assert(lvalue); + assert(rvalue); + + if (isempty(rvalue)) + *emit = LLDP_EMIT_NO; + else if (streq(rvalue, "nearest-bridge")) + *emit = LLDP_EMIT_NEAREST_BRIDGE; + else if (streq(rvalue, "non-tpmr-bridge")) + *emit = LLDP_EMIT_NON_TPMR_BRIDGE; + else if (streq(rvalue, "customer-bridge")) + *emit = LLDP_EMIT_CUSTOMER_BRIDGE; + else { + r = parse_boolean(rvalue); + if (r < 0) { + log_syntax(unit, LOG_ERR, filename, line, 0, "Failed to parse LLDP emission setting, ignoring: %s", rvalue); + return 0; + } + + *emit = r ? LLDP_EMIT_NEAREST_BRIDGE : LLDP_EMIT_NO; + } + + return 0; +} |