src/network/networkd-lldp-rx.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   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-network.h"
  13 #include "string-table.h"
  14 #include "string-util.h"
  15 #include "strv.h"
  16 #include "tmpfile-util.h"
  17
  18 DEFINE_CONFIG_PARSE_ENUM(config_parse_lldp_mode, lldp_mode, LLDPMode, "Failed to parse LLDP= setting.");
  19
  20 static const char* const lldp_mode_table[_LLDP_MODE_MAX] = {
  21         [LLDP_MODE_NO] = "no",
  22         [LLDP_MODE_YES] = "yes",
  23         [LLDP_MODE_ROUTERS_ONLY] = "routers-only",
  24 };
  25
  26 DEFINE_STRING_TABLE_LOOKUP_WITH_BOOLEAN(lldp_mode, LLDPMode, LLDP_MODE_YES);
  27
  28 bool link_lldp_rx_enabled(Link *link) {
  29         assert(link);
  30
  31         if (link->flags & IFF_LOOPBACK)
  32                 return false;
  33
  34         if (link->iftype != ARPHRD_ETHER)
  35                 return false;
  36
  37         if (!link->network)
  38                 return false;
  39
  40         /* LLDP should be handled on bridge and bond slaves as those have a direct connection to their peers,
  41          * not on the bridge/bond master. Linux doesn't even (by default) forward lldp packets to the bridge
  42          * master.*/
  43         if (link->kind && STR_IN_SET(link->kind, "bridge", "bond"))
  44                 return false;
  45
  46         return link->network->lldp_mode != LLDP_MODE_NO;
  47 }
  48
  49 static void lldp_handler(sd_lldp *lldp, sd_lldp_event event, sd_lldp_neighbor *n, void *userdata) {
  50         Link *link = userdata;
  51         int r;
  52
  53         assert(link);
  54
  55         (void) link_lldp_save(link);
  56
  57         if (link_lldp_emit_enabled(link) && event == SD_LLDP_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                 r = link_lldp_emit_start(link);
  63                 if (r < 0)
  64                         log_link_warning_errno(link, r, "Failed to restart LLDP transmission: %m");
  65         }
  66 }
  67
  68 int link_lldp_rx_configure(Link *link) {
  69         int r;
  70
  71         r = sd_lldp_new(&link->lldp);
  72         if (r < 0)
  73                 return r;
  74
  75         r = sd_lldp_set_ifindex(link->lldp, link->ifindex);
  76         if (r < 0)
  77                 return r;
  78
  79         r = sd_lldp_match_capabilities(link->lldp,
  80                                        link->network->lldp_mode == LLDP_MODE_ROUTERS_ONLY ?
  81                                        SD_LLDP_SYSTEM_CAPABILITIES_ALL_ROUTERS :
  82                                        SD_LLDP_SYSTEM_CAPABILITIES_ALL);
  83         if (r < 0)
  84                 return r;
  85
  86         r = sd_lldp_set_filter_address(link->lldp, &link->mac);
  87         if (r < 0)
  88                 return r;
  89
  90         r = sd_lldp_attach_event(link->lldp, NULL, 0);
  91         if (r < 0)
  92                 return r;
  93
  94         r = sd_lldp_set_callback(link->lldp, lldp_handler, link);
  95         if (r < 0)
  96                 return r;
  97
  98         r = link_update_lldp(link);
  99         if (r < 0)
 100                 return r;
 101
 102         return 0;
 103 }
 104
 105 int link_update_lldp(Link *link) {
 106         int r;
 107
 108         assert(link);
 109
 110         if (!link->lldp)
 111                 return 0;
 112
 113         if (link->flags & IFF_UP) {
 114                 r = sd_lldp_start(link->lldp);
 115                 if (r < 0)
 116                         return log_link_warning_errno(link, r, "Failed to start LLDP: %m");
 117                 if (r > 0)
 118                         log_link_debug(link, "Started LLDP.");
 119         } else {
 120                 r = sd_lldp_stop(link->lldp);
 121                 if (r < 0)
 122                         return log_link_warning_errno(link, r, "Failed to stop LLDP: %m");
 123                 if (r > 0)
 124                         log_link_debug(link, "Stopped LLDP.");
 125         }
 126
 127         return r;
 128 }
 129
 130 int link_lldp_save(Link *link) {
 131         _cleanup_free_ char *temp_path = NULL;
 132         _cleanup_fclose_ FILE *f = NULL;
 133         sd_lldp_neighbor **l = NULL;
 134         int n = 0, r, i;
 135
 136         assert(link);
 137         assert(link->lldp_file);
 138
 139         if (!link->lldp) {
 140                 (void) unlink(link->lldp_file);
 141                 return 0;
 142         }
 143
 144         r = sd_lldp_get_neighbors(link->lldp, &l);
 145         if (r < 0)
 146                 goto finish;
 147         if (r == 0) {
 148                 (void) unlink(link->lldp_file);
 149                 goto finish;
 150         }
 151
 152         n = r;
 153
 154         r = fopen_temporary(link->lldp_file, &f, &temp_path);
 155         if (r < 0)
 156                 goto finish;
 157
 158         fchmod(fileno(f), 0644);
 159
 160         for (i = 0; i < n; i++) {
 161                 const void *p;
 162                 le64_t u;
 163                 size_t sz;
 164
 165                 r = sd_lldp_neighbor_get_raw(l[i], &p, &sz);
 166                 if (r < 0)
 167                         goto finish;
 168
 169                 u = htole64(sz);
 170                 (void) fwrite(&u, 1, sizeof(u), f);
 171                 (void) fwrite(p, 1, sz, f);
 172         }
 173
 174         r = fflush_and_check(f);
 175         if (r < 0)
 176                 goto finish;
 177
 178         if (rename(temp_path, link->lldp_file) < 0) {
 179                 r = -errno;
 180                 goto finish;
 181         }
 182
 183 finish:
 184         if (r < 0) {
 185                 (void) unlink(link->lldp_file);
 186                 if (temp_path)
 187                         (void) unlink(temp_path);
 188
 189                 log_link_error_errno(link, r, "Failed to save LLDP data to %s: %m", link->lldp_file);
 190         }
 191
 192         if (l) {
 193                 for (i = 0; i < n; i++)
 194                         sd_lldp_neighbor_unref(l[i]);
 195                 free(l);
 196         }
 197
 198         return r;
 199 }