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_handler(sd_lldp *lldp, sd_lldp_event_t event, sd_lldp_neighbor *n, void *userdata) {
  52         Link *link = userdata;
  53         int r;
  54
  55         assert(link);
  56
  57         (void) link_lldp_save(link);
  58
  59         if (link_lldp_emit_enabled(link) && event == SD_LLDP_EVENT_ADDED) {
  60                 /* If we received information about a new neighbor, restart the LLDP "fast" logic */
  61
  62                 log_link_debug(link, "Received LLDP datagram from previously unknown neighbor, restarting 'fast' LLDP transmission.");
  63
  64                 r = link_lldp_emit_start(link);
  65                 if (r < 0)
  66                         log_link_warning_errno(link, r, "Failed to restart LLDP transmission: %m");
  67         }
  68 }
  69
  70 int link_lldp_rx_configure(Link *link) {
  71         int r;
  72
  73         if (!link_lldp_rx_enabled(link))
  74                 return 0;
  75
  76         if (link->lldp)
  77                 return -EBUSY;
  78
  79         r = sd_lldp_new(&link->lldp);
  80         if (r < 0)
  81                 return r;
  82
  83         r = sd_lldp_attach_event(link->lldp, link->manager->event, 0);
  84         if (r < 0)
  85                 return r;
  86
  87         r = sd_lldp_set_ifindex(link->lldp, link->ifindex);
  88         if (r < 0)
  89                 return r;
  90
  91         r = sd_lldp_match_capabilities(link->lldp,
  92                                        link->network->lldp_mode == LLDP_MODE_ROUTERS_ONLY ?
  93                                        SD_LLDP_SYSTEM_CAPABILITIES_ALL_ROUTERS :
  94                                        SD_LLDP_SYSTEM_CAPABILITIES_ALL);
  95         if (r < 0)
  96                 return r;
  97
  98         r = sd_lldp_set_filter_address(link->lldp, &link->hw_addr.ether);
  99         if (r < 0)
 100                 return r;
 101
 102         r = sd_lldp_set_callback(link->lldp, lldp_handler, link);
 103         if (r < 0)
 104                 return r;
 105
 106         r = link_update_lldp(link);
 107         if (r < 0)
 108                 return r;
 109
 110         return 0;
 111 }
 112
 113 int link_update_lldp(Link *link) {
 114         int r;
 115
 116         assert(link);
 117
 118         if (!link->lldp)
 119                 return 0;
 120
 121         if (link->flags & IFF_UP) {
 122                 r = sd_lldp_start(link->lldp);
 123                 if (r < 0)
 124                         return log_link_warning_errno(link, r, "Failed to start LLDP: %m");
 125                 if (r > 0)
 126                         log_link_debug(link, "Started LLDP.");
 127         } else {
 128                 r = sd_lldp_stop(link->lldp);
 129                 if (r < 0)
 130                         return log_link_warning_errno(link, r, "Failed to stop LLDP: %m");
 131                 if (r > 0)
 132                         log_link_debug(link, "Stopped LLDP.");
 133         }
 134
 135         return r;
 136 }
 137
 138 int link_lldp_save(Link *link) {
 139         _cleanup_(unlink_and_freep) char *temp_path = NULL;
 140         _cleanup_fclose_ FILE *f = NULL;
 141         sd_lldp_neighbor **l = NULL;
 142         int n = 0, r, i;
 143
 144         assert(link);
 145         assert(link->lldp_file);
 146
 147         if (!link->lldp) {
 148                 (void) unlink(link->lldp_file);
 149                 return 0;
 150         }
 151
 152         r = sd_lldp_get_neighbors(link->lldp, &l);
 153         if (r < 0)
 154                 return r;
 155         if (r == 0) {
 156                 (void) unlink(link->lldp_file);
 157                 return 0;
 158         }
 159
 160         n = r;
 161
 162         r = fopen_temporary(link->lldp_file, &f, &temp_path);
 163         if (r < 0)
 164                 goto finish;
 165
 166         (void) fchmod(fileno(f), 0644);
 167
 168         for (i = 0; i < n; i++) {
 169                 const void *p;
 170                 le64_t u;
 171                 size_t sz;
 172
 173                 r = sd_lldp_neighbor_get_raw(l[i], &p, &sz);
 174                 if (r < 0)
 175                         goto finish;
 176
 177                 u = htole64(sz);
 178                 (void) fwrite(&u, 1, sizeof(u), f);
 179                 (void) fwrite(p, 1, sz, f);
 180         }
 181
 182         r = fflush_and_check(f);
 183         if (r < 0)
 184                 goto finish;
 185
 186         r = conservative_rename(temp_path, link->lldp_file);
 187         if (r < 0)
 188                 goto finish;
 189
 190 finish:
 191         if (r < 0)
 192                 log_link_error_errno(link, r, "Failed to save LLDP data to %s: %m", link->lldp_file);
 193
 194         if (l) {
 195                 for (i = 0; i < n; i++)
 196                         sd_lldp_neighbor_unref(l[i]);
 197                 free(l);
 198         }
 199
 200         return r;
 201 }