src/network/networkd-lldp-rx.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <net/if.h>
   4 #include <net/if_arp.h>
   5 #include <unistd.h>
   6
   7 #include "fd-util.h"
   8 #include "fileio.h"
   9 #include "fs-util.h"
  10 #include "networkd-link.h"
  11 #include "networkd-lldp-rx.h"
  12 #include "networkd-lldp-tx.h"
  13 #include "networkd-manager.h"
  14 #include "networkd-network.h"
  15 #include "string-table.h"
  16 #include "string-util.h"
  17 #include "strv.h"
  18 #include "tmpfile-util.h"
  19
  20 DEFINE_CONFIG_PARSE_ENUM(config_parse_lldp_mode, lldp_mode, LLDPMode, "Failed to parse LLDP= setting.");
  21
  22 static const char* const lldp_mode_table[_LLDP_MODE_MAX] = {
  23         [LLDP_MODE_NO] = "no",
  24         [LLDP_MODE_YES] = "yes",
  25         [LLDP_MODE_ROUTERS_ONLY] = "routers-only",
  26 };
  27
  28 DEFINE_STRING_TABLE_LOOKUP_WITH_BOOLEAN(lldp_mode, LLDPMode, LLDP_MODE_YES);
  29
  30 static bool link_lldp_rx_enabled(Link *link) {
  31         assert(link);
  32
  33         if (link->flags & IFF_LOOPBACK)
  34                 return false;
  35
  36         if (link->iftype != ARPHRD_ETHER)
  37                 return false;
  38
  39         if (!link->network)
  40                 return false;
  41
  42         /* LLDP should be handled on bridge and bond slaves as those have a direct connection to their peers,
  43          * not on the bridge/bond master. Linux doesn't even (by default) forward lldp packets to the bridge
  44          * master. */
  45         if (link->kind && STR_IN_SET(link->kind, "bridge", "bond"))
  46                 return false;
  47
  48         return link->network->lldp_mode != LLDP_MODE_NO;
  49 }
  50
  51 static void lldp_rx_handler(sd_lldp_rx *lldp_rx, sd_lldp_rx_event_t event, sd_lldp_neighbor *n, void *userdata) {
  52         Link *link = ASSERT_PTR(userdata);
  53         int r;
  54
  55         (void) link_lldp_save(link);
  56
  57         if (link->lldp_tx && event == SD_LLDP_RX_EVENT_ADDED) {
  58                 /* If we received information about a new neighbor, restart the LLDP "fast" logic */
  59
  60                 log_link_debug(link, "Received LLDP datagram from previously unknown neighbor, restarting 'fast' LLDP transmission.");
  61
  62                 (void) sd_lldp_tx_stop(link->lldp_tx);
  63                 r = sd_lldp_tx_start(link->lldp_tx);
  64                 if (r < 0)
  65                         log_link_warning_errno(link, r, "Failed to restart LLDP transmission: %m");
  66         }
  67 }
  68
  69 int link_lldp_rx_configure(Link *link) {
  70         int r;
  71
  72         if (!link_lldp_rx_enabled(link))
  73                 return 0;
  74
  75         if (link->lldp_rx)
  76                 return -EBUSY;
  77
  78         r = sd_lldp_rx_new(&link->lldp_rx);
  79         if (r < 0)
  80                 return r;
  81
  82         r = sd_lldp_rx_attach_event(link->lldp_rx, link->manager->event, 0);
  83         if (r < 0)
  84                 return r;
  85
  86         r = sd_lldp_rx_set_ifindex(link->lldp_rx, link->ifindex);
  87         if (r < 0)
  88                 return r;
  89
  90         r = sd_lldp_rx_match_capabilities(link->lldp_rx,
  91                                           link->network->lldp_mode == LLDP_MODE_ROUTERS_ONLY ?
  92                                           SD_LLDP_SYSTEM_CAPABILITIES_ALL_ROUTERS :
  93                                           SD_LLDP_SYSTEM_CAPABILITIES_ALL);
  94         if (r < 0)
  95                 return r;
  96
  97         r = sd_lldp_rx_set_filter_address(link->lldp_rx, &link->hw_addr.ether);
  98         if (r < 0)
  99                 return r;
 100
 101         r = sd_lldp_rx_set_callback(link->lldp_rx, lldp_rx_handler, link);
 102         if (r < 0)
 103                 return r;
 104
 105         return 0;
 106 }
 107
 108 int link_lldp_save(Link *link) {
 109         _cleanup_(unlink_and_freep) char *temp_path = NULL;
 110         _cleanup_fclose_ FILE *f = NULL;
 111         sd_lldp_neighbor **l = NULL;
 112         int n = 0, r, i;
 113
 114         assert(link);
 115
 116         if (isempty(link->lldp_file))
 117                 return 0; /* Do not update state file when running in test mode. */
 118
 119         if (!link->lldp_rx) {
 120                 (void) unlink(link->lldp_file);
 121                 return 0;
 122         }
 123
 124         r = sd_lldp_rx_get_neighbors(link->lldp_rx, &l);
 125         if (r < 0)
 126                 return r;
 127         if (r == 0) {
 128                 (void) unlink(link->lldp_file);
 129                 return 0;
 130         }
 131
 132         n = r;
 133
 134         r = fopen_temporary(link->lldp_file, &f, &temp_path);
 135         if (r < 0)
 136                 goto finish;
 137
 138         (void) fchmod(fileno(f), 0644);
 139
 140         for (i = 0; i < n; i++) {
 141                 const void *p;
 142                 le64_t u;
 143                 size_t sz;
 144
 145                 r = sd_lldp_neighbor_get_raw(l[i], &p, &sz);
 146                 if (r < 0)
 147                         goto finish;
 148
 149                 u = htole64(sz);
 150                 fwrite(&u, 1, sizeof(u), f);
 151                 fwrite(p, 1, sz, f);
 152         }
 153
 154         r = fflush_and_check(f);
 155         if (r < 0)
 156                 goto finish;
 157
 158         r = conservative_rename(temp_path, link->lldp_file);
 159         if (r < 0)
 160                 goto finish;
 161
 162 finish:
 163         if (r < 0)
 164                 log_link_error_errno(link, r, "Failed to save LLDP data to %s: %m", link->lldp_file);
 165
 166         if (l) {
 167                 for (i = 0; i < n; i++)
 168                         sd_lldp_neighbor_unref(l[i]);
 169                 free(l);
 170         }
 171
 172         return r;
 173 }