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 "networkd-link.h"
  10 #include "networkd-lldp-rx.h"
  11 #include "networkd-lldp-tx.h"
  12 #include "networkd-manager.h"
  13 #include "networkd-network.h"
  14 #include "string-table.h"
  15 #include "string-util.h"
  16 #include "strv.h"
  17 #include "tmpfile-util.h"
  18
  19 DEFINE_CONFIG_PARSE_ENUM(config_parse_lldp_mode, lldp_mode, LLDPMode, "Failed to parse LLDP= setting.");
  20
  21 static const char* const lldp_mode_table[_LLDP_MODE_MAX] = {
  22         [LLDP_MODE_NO] = "no",
  23         [LLDP_MODE_YES] = "yes",
  24         [LLDP_MODE_ROUTERS_ONLY] = "routers-only",
  25 };
  26
  27 DEFINE_STRING_TABLE_LOOKUP_WITH_BOOLEAN(lldp_mode, LLDPMode, LLDP_MODE_YES);
  28
  29 static bool link_lldp_rx_enabled(Link *link) {
  30         assert(link);
  31
  32         if (link->flags & IFF_LOOPBACK)
  33                 return false;
  34
  35         if (link->iftype != ARPHRD_ETHER)
  36                 return false;
  37
  38         if (!link->network)
  39                 return false;
  40
  41         /* LLDP should be handled on bridge and bond slaves as those have a direct connection to their peers,
  42          * not on the bridge/bond master. Linux doesn't even (by default) forward lldp packets to the bridge
  43          * master.*/
  44         if (link->kind && STR_IN_SET(link->kind, "bridge", "bond"))
  45                 return false;
  46
  47         return link->network->lldp_mode != LLDP_MODE_NO;
  48 }
  49
  50 static void lldp_handler(sd_lldp *lldp, sd_lldp_event event, sd_lldp_neighbor *n, void *userdata) {
  51         Link *link = userdata;
  52         int r;
  53
  54         assert(link);
  55
  56         (void) link_lldp_save(link);
  57
  58         if (link_lldp_emit_enabled(link) && event == SD_LLDP_EVENT_ADDED) {
  59                 /* If we received information about a new neighbor, restart the LLDP "fast" logic */
  60
  61                 log_link_debug(link, "Received LLDP datagram from previously unknown neighbor, restarting 'fast' LLDP transmission.");
  62
  63                 r = link_lldp_emit_start(link);
  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) {
  76                 r = sd_lldp_new(&link->lldp);
  77                 if (r < 0)
  78                         return r;
  79
  80                 r = sd_lldp_attach_event(link->lldp, link->manager->event, 0);
  81                 if (r < 0)
  82                         return r;
  83         }
  84
  85         r = sd_lldp_set_ifindex(link->lldp, link->ifindex);
  86         if (r < 0)
  87                 return r;
  88
  89         r = sd_lldp_match_capabilities(link->lldp,
  90                                        link->network->lldp_mode == LLDP_MODE_ROUTERS_ONLY ?
  91                                        SD_LLDP_SYSTEM_CAPABILITIES_ALL_ROUTERS :
  92                                        SD_LLDP_SYSTEM_CAPABILITIES_ALL);
  93         if (r < 0)
  94                 return r;
  95
  96         r = sd_lldp_set_filter_address(link->lldp, &link->hw_addr.addr.ether);
  97         if (r < 0)
  98                 return r;
  99
 100         r = sd_lldp_set_callback(link->lldp, lldp_handler, link);
 101         if (r < 0)
 102                 return r;
 103
 104         r = link_update_lldp(link);
 105         if (r < 0)
 106                 return r;
 107
 108         return 0;
 109 }
 110
 111 int link_update_lldp(Link *link) {
 112         int r;
 113
 114         assert(link);
 115
 116         if (!link->lldp)
 117                 return 0;
 118
 119         if (link->flags & IFF_UP) {
 120                 r = sd_lldp_start(link->lldp);
 121                 if (r < 0)
 122                         return log_link_warning_errno(link, r, "Failed to start LLDP: %m");
 123                 if (r > 0)
 124                         log_link_debug(link, "Started LLDP.");
 125         } else {
 126                 r = sd_lldp_stop(link->lldp);
 127                 if (r < 0)
 128                         return log_link_warning_errno(link, r, "Failed to stop LLDP: %m");
 129                 if (r > 0)
 130                         log_link_debug(link, "Stopped LLDP.");
 131         }
 132
 133         return r;
 134 }
 135
 136 int link_lldp_save(Link *link) {
 137         _cleanup_free_ char *temp_path = NULL;
 138         _cleanup_fclose_ FILE *f = NULL;
 139         sd_lldp_neighbor **l = NULL;
 140         int n = 0, r, i;
 141
 142         assert(link);
 143         assert(link->lldp_file);
 144
 145         if (!link->lldp) {
 146                 (void) unlink(link->lldp_file);
 147                 return 0;
 148         }
 149
 150         r = sd_lldp_get_neighbors(link->lldp, &l);
 151         if (r < 0)
 152                 goto finish;
 153         if (r == 0) {
 154                 (void) unlink(link->lldp_file);
 155                 goto finish;
 156         }
 157
 158         n = r;
 159
 160         r = fopen_temporary(link->lldp_file, &f, &temp_path);
 161         if (r < 0)
 162                 goto finish;
 163
 164         fchmod(fileno(f), 0644);
 165
 166         for (i = 0; i < n; i++) {
 167                 const void *p;
 168                 le64_t u;
 169                 size_t sz;
 170
 171                 r = sd_lldp_neighbor_get_raw(l[i], &p, &sz);
 172                 if (r < 0)
 173                         goto finish;
 174
 175                 u = htole64(sz);
 176                 (void) fwrite(&u, 1, sizeof(u), f);
 177                 (void) fwrite(p, 1, sz, f);
 178         }
 179
 180         r = fflush_and_check(f);
 181         if (r < 0)
 182                 goto finish;
 183
 184         if (rename(temp_path, link->lldp_file) < 0) {
 185                 r = -errno;
 186                 goto finish;
 187         }
 188
 189 finish:
 190         if (r < 0) {
 191                 (void) unlink(link->lldp_file);
 192                 if (temp_path)
 193                         (void) unlink(temp_path);
 194
 195                 log_link_error_errno(link, r, "Failed to save LLDP data to %s: %m", link->lldp_file);
 196         }
 197
 198         if (l) {
 199                 for (i = 0; i < n; i++)
 200                         sd_lldp_neighbor_unref(l[i]);
 201                 free(l);
 202         }
 203
 204         return r;
 205 }