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 "tmpfile-util.h"
  16
  17 DEFINE_CONFIG_PARSE_ENUM(config_parse_lldp_mode, lldp_mode, LLDPMode, "Failed to parse LLDP= setting.");
  18
  19 static const char* const lldp_mode_table[_LLDP_MODE_MAX] = {
  20         [LLDP_MODE_NO] = "no",
  21         [LLDP_MODE_YES] = "yes",
  22         [LLDP_MODE_ROUTERS_ONLY] = "routers-only",
  23 };
  24
  25 DEFINE_STRING_TABLE_LOOKUP_WITH_BOOLEAN(lldp_mode, LLDPMode, LLDP_MODE_YES);
  26
  27 bool link_lldp_rx_enabled(Link *link) {
  28         assert(link);
  29
  30         if (link->flags & IFF_LOOPBACK)
  31                 return false;
  32
  33         if (link->iftype != ARPHRD_ETHER)
  34                 return false;
  35
  36         if (!link->network)
  37                 return false;
  38
  39         /* LLDP should be handled on bridge slaves as those have a direct
  40          * connection to their peers not on the bridge master. Linux doesn't
  41          * even (by default) forward lldp packets to the bridge master.*/
  42         if (streq_ptr("bridge", link->kind))
  43                 return false;
  44
  45         return link->network->lldp_mode != LLDP_MODE_NO;
  46 }
  47
  48 static void lldp_handler(sd_lldp *lldp, sd_lldp_event event, sd_lldp_neighbor *n, void *userdata) {
  49         Link *link = userdata;
  50         int r;
  51
  52         assert(link);
  53
  54         (void) link_lldp_save(link);
  55
  56         if (link_lldp_emit_enabled(link) && event == SD_LLDP_EVENT_ADDED) {
  57                 /* If we received information about a new neighbor, restart the LLDP "fast" logic */
  58
  59                 log_link_debug(link, "Received LLDP datagram from previously unknown neighbor, restarting 'fast' LLDP transmission.");
  60
  61                 r = link_lldp_emit_start(link);
  62                 if (r < 0)
  63                         log_link_warning_errno(link, r, "Failed to restart LLDP transmission: %m");
  64         }
  65 }
  66
  67 int link_lldp_rx_configure(Link *link) {
  68         int r;
  69
  70         r = sd_lldp_new(&link->lldp);
  71         if (r < 0)
  72                 return r;
  73
  74         r = sd_lldp_set_ifindex(link->lldp, link->ifindex);
  75         if (r < 0)
  76                 return r;
  77
  78         r = sd_lldp_match_capabilities(link->lldp,
  79                                        link->network->lldp_mode == LLDP_MODE_ROUTERS_ONLY ?
  80                                        SD_LLDP_SYSTEM_CAPABILITIES_ALL_ROUTERS :
  81                                        SD_LLDP_SYSTEM_CAPABILITIES_ALL);
  82         if (r < 0)
  83                 return r;
  84
  85         r = sd_lldp_set_filter_address(link->lldp, &link->mac);
  86         if (r < 0)
  87                 return r;
  88
  89         r = sd_lldp_attach_event(link->lldp, NULL, 0);
  90         if (r < 0)
  91                 return r;
  92
  93         r = sd_lldp_set_callback(link->lldp, lldp_handler, link);
  94         if (r < 0)
  95                 return r;
  96
  97         r = link_update_lldp(link);
  98         if (r < 0)
  99                 return r;
 100
 101         return 0;
 102 }
 103
 104 int link_update_lldp(Link *link) {
 105         int r;
 106
 107         assert(link);
 108
 109         if (!link->lldp)
 110                 return 0;
 111
 112         if (link->flags & IFF_UP) {
 113                 r = sd_lldp_start(link->lldp);
 114                 if (r < 0)
 115                         return log_link_warning_errno(link, r, "Failed to start LLDP: %m");
 116                 if (r > 0)
 117                         log_link_debug(link, "Started LLDP.");
 118         } else {
 119                 r = sd_lldp_stop(link->lldp);
 120                 if (r < 0)
 121                         return log_link_warning_errno(link, r, "Failed to stop LLDP: %m");
 122                 if (r > 0)
 123                         log_link_debug(link, "Stopped LLDP.");
 124         }
 125
 126         return r;
 127 }
 128
 129 int link_lldp_save(Link *link) {
 130         _cleanup_free_ char *temp_path = NULL;
 131         _cleanup_fclose_ FILE *f = NULL;
 132         sd_lldp_neighbor **l = NULL;
 133         int n = 0, r, i;
 134
 135         assert(link);
 136         assert(link->lldp_file);
 137
 138         if (!link->lldp) {
 139                 (void) unlink(link->lldp_file);
 140                 return 0;
 141         }
 142
 143         r = sd_lldp_get_neighbors(link->lldp, &l);
 144         if (r < 0)
 145                 goto finish;
 146         if (r == 0) {
 147                 (void) unlink(link->lldp_file);
 148                 goto finish;
 149         }
 150
 151         n = r;
 152
 153         r = fopen_temporary(link->lldp_file, &f, &temp_path);
 154         if (r < 0)
 155                 goto finish;
 156
 157         fchmod(fileno(f), 0644);
 158
 159         for (i = 0; i < n; i++) {
 160                 const void *p;
 161                 le64_t u;
 162                 size_t sz;
 163
 164                 r = sd_lldp_neighbor_get_raw(l[i], &p, &sz);
 165                 if (r < 0)
 166                         goto finish;
 167
 168                 u = htole64(sz);
 169                 (void) fwrite(&u, 1, sizeof(u), f);
 170                 (void) fwrite(p, 1, sz, f);
 171         }
 172
 173         r = fflush_and_check(f);
 174         if (r < 0)
 175                 goto finish;
 176
 177         if (rename(temp_path, link->lldp_file) < 0) {
 178                 r = -errno;
 179                 goto finish;
 180         }
 181
 182 finish:
 183         if (r < 0) {
 184                 (void) unlink(link->lldp_file);
 185                 if (temp_path)
 186                         (void) unlink(temp_path);
 187
 188                 log_link_error_errno(link, r, "Failed to save LLDP data to %s: %m", link->lldp_file);
 189         }
 190
 191         if (l) {
 192                 for (i = 0; i < n; i++)
 193                         sd_lldp_neighbor_unref(l[i]);
 194                 free(l);
 195         }
 196
 197         return r;
 198 }