src/networkd/link.c

   1 /*#############################################################################
   2 #                                                                             #
   3 # IPFire.org - A linux based firewall                                         #
   4 # Copyright (C) 2023 IPFire Network Development Team                          #
   5 #                                                                             #
   6 # This program is free software: you can redistribute it and/or modify        #
   7 # it under the terms of the GNU General Public License as published by        #
   8 # the Free Software Foundation, either version 3 of the License, or           #
   9 # (at your option) any later version.                                         #
  10 #                                                                             #
  11 # This program is distributed in the hope that it will be useful,             #
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of              #
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               #
  14 # GNU General Public License for more details.                                #
  15 #                                                                             #
  16 # You should have received a copy of the GNU General Public License           #
  17 # along with this program.  If not, see <http://www.gnu.org/licenses/>.       #
  18 #                                                                             #
  19 #############################################################################*/
  20
  21 #include <stddef.h>
  22 #include <stdlib.h>
  23
  24 #include <systemd/sd-netlink.h>
  25
  26 #include "daemon.h"
  27 #include "link.h"
  28 #include "links.h"
  29 #include "logging.h"
  30
  31 struct nw_link {
  32         struct nw_daemon* daemon;
  33         int nrefs;
  34
  35         // Interface Index
  36         int ifindex;
  37 };
  38
  39 int nw_link_create(struct nw_link** link, struct nw_daemon* daemon, int ifindex) {
  40         // Allocate a new object
  41         struct nw_link* l = calloc(1, sizeof(*l));
  42         if (!l)
  43                 return 1;
  44
  45         // Store a reference to the daemon
  46         l->daemon = nw_daemon_ref(daemon);
  47
  48         // Initialize the reference counter
  49         l->nrefs = 1;
  50
  51         // Store the ifindex
  52         l->ifindex = ifindex;
  53
  54         DEBUG("New link allocated (ifindex = %d)\n", l->ifindex);
  55
  56         *link = l;
  57
  58         return 0;
  59 }
  60
  61 static void nw_link_free(struct nw_link* link) {
  62         DEBUG("Freeing link (ifindex = %d)\n", link->ifindex);
  63
  64         if (link->daemon)
  65                 nw_daemon_unref(link->daemon);
  66 }
  67
  68 struct nw_link* nw_link_ref(struct nw_link* link) {
  69         link->nrefs++;
  70
  71         return link;
  72 }
  73
  74 struct nw_link* nw_link_unref(struct nw_link* link) {
  75         if (--link->nrefs > 0)
  76                 return link;
  77
  78         nw_link_free(link);
  79         return NULL;
  80 }
  81
  82 int nw_link_ifindex(struct nw_link* link) {
  83         return link->ifindex;
  84 }
  85
  86 int nw_link_process(sd_netlink* rtnl, sd_netlink_message* message, void* data) {
  87         struct nw_links* links = NULL;
  88         struct nw_link* link = NULL;
  89         const char* ifname = NULL;
  90         int ifindex;
  91         uint16_t type;
  92         int r;
  93
  94         struct nw_daemon* daemon = (struct nw_daemon*)data;
  95
  96         // Fetch links
  97         links = nw_daemon_links(daemon);
  98         if (!links) {
  99                 r = 1;
 100                 goto ERROR;
 101         }
 102
 103         // Check if this message could be received
 104         if (sd_netlink_message_is_error(message)) {
 105                 r = sd_netlink_message_get_errno(message);
 106                 if (r < 0)
 107                         ERROR("Could not receive link message: %m\n");
 108
 109                 goto IGNORE;
 110         }
 111
 112         // Fetch the message type
 113         r = sd_netlink_message_get_type(message, &type);
 114         if (r < 0) {
 115                 ERROR("Could not fetch message type: %m\n");
 116                 goto IGNORE;
 117         }
 118
 119         // Check type
 120         switch (type) {
 121                 case RTM_NEWLINK:
 122                 case RTM_DELLINK:
 123                         break;
 124
 125                 default:
 126                         ERROR("Received an unexpected message (type %u)\n", type);
 127                         goto IGNORE;
 128         }
 129
 130         // Fetch the interface index
 131         r = sd_rtnl_message_link_get_ifindex(message, &ifindex);
 132         if (r < 0) {
 133                 ERROR("Could not fetch ifindex: %m\n");
 134                 goto IGNORE;
 135         }
 136
 137         // Check interface index
 138         if (ifindex <= 0) {
 139                 ERROR("Received an invalid ifindex\n");
 140                 goto IGNORE;
 141         }
 142
 143         // Fetch the interface name
 144         r = sd_netlink_message_read_string(message, IFLA_IFNAME, &ifname);
 145         if (r < 0) {
 146                 ERROR("Received a netlink message without interface name: %m\n");
 147                 goto IGNORE;
 148         }
 149
 150         // Try finding an existing link
 151         link = nw_daemon_get_link_by_ifindex(daemon, ifindex);
 152
 153         switch (type) {
 154                 case RTM_NEWLINK:
 155                         // If the link doesn't exist, create it
 156                         if (!link) {
 157                                 r = nw_link_create(&link, daemon, ifindex);
 158                                 if (r) {
 159                                         ERROR("Could not create link: %m\n");
 160                                         goto ERROR;
 161                                 }
 162
 163                                 // Add it to the list
 164                                 r = nw_links_add_link(links, link);
 165                                 if (r)
 166                                         goto ERROR;
 167                         }
 168
 169                         // TODO Import any data from the netlink message
 170
 171                         break;
 172
 173                 case RTM_DELLINK:
 174                         if (link)
 175                                 nw_links_drop_link(links, link);
 176
 177                         break;
 178         }
 179
 180 IGNORE:
 181         r = 0;
 182
 183 ERROR:
 184         if (links)
 185                 nw_links_unref(links);
 186         if (link)
 187                 nw_link_unref(link);
 188
 189         return r;
 190 }