system-linux.c

   1 #include <sys/socket.h>
   2 #include <sys/ioctl.h>
   3 #include <sys/stat.h>
   4
   5 #include <linux/rtnetlink.h>
   6 #include <linux/sockios.h>
   7 #include <linux/if_vlan.h>
   8 #include <linux/if_bridge.h>
   9
  10 #include <unistd.h>
  11 #include <string.h>
  12 #include <fcntl.h>
  13 #include <glob.h>
  14
  15 #include <netlink/msg.h>
  16 #include <netlink/attr.h>
  17 #include <netlink/socket.h>
  18 #include <libubox/uloop.h>
  19
  20 #include "netifd.h"
  21 #include "device.h"
  22 #include "system.h"
  23
  24 static int sock_ioctl = -1;
  25 static struct nl_sock *sock_rtnl = NULL;
  26 static struct nl_sock *sock_rtnl_event = NULL;
  27
  28 static void handler_rtnl_event(struct uloop_fd *u, unsigned int events);
  29 static int cb_rtnl_event(struct nl_msg *msg, void *arg);
  30 static struct uloop_fd rtnl_event = {.cb = handler_rtnl_event};
  31 static struct nl_cb *nl_cb_rtnl_event;
  32
  33 int system_init(void)
  34 {
  35         sock_ioctl = socket(AF_LOCAL, SOCK_DGRAM, 0);
  36         fcntl(sock_ioctl, F_SETFD, fcntl(sock_ioctl, F_GETFD) | FD_CLOEXEC);
  37
  38         // Prepare socket for routing / address control
  39         sock_rtnl = nl_socket_alloc();
  40         if (!sock_rtnl)
  41                 return -1;
  42
  43         if (nl_connect(sock_rtnl, NETLINK_ROUTE))
  44                 goto error_free_sock;
  45
  46         // Prepare socket for link events
  47         nl_cb_rtnl_event = nl_cb_alloc(NL_CB_DEFAULT);
  48         if (!nl_cb_rtnl_event)
  49                 goto error_free_sock;
  50
  51         nl_cb_set(nl_cb_rtnl_event, NL_CB_VALID, NL_CB_CUSTOM,
  52                   cb_rtnl_event, NULL);
  53
  54         sock_rtnl_event = nl_socket_alloc();
  55         if (!sock_rtnl_event)
  56                 goto error_free_cb;
  57
  58         if (nl_connect(sock_rtnl_event, NETLINK_ROUTE))
  59                 goto error_free_event;
  60
  61         // Receive network link events form kernel
  62         nl_socket_add_membership(sock_rtnl_event, RTNLGRP_LINK);
  63
  64         rtnl_event.fd = nl_socket_get_fd(sock_rtnl_event);
  65         uloop_fd_add(&rtnl_event, ULOOP_READ | ULOOP_EDGE_TRIGGER);
  66
  67         return 0;
  68
  69 error_free_event:
  70         nl_socket_free(sock_rtnl_event);
  71         sock_rtnl_event = NULL;
  72 error_free_cb:
  73         nl_cb_put(nl_cb_rtnl_event);
  74         nl_cb_rtnl_event = NULL;
  75 error_free_sock:
  76         nl_socket_free(sock_rtnl);
  77         sock_rtnl = NULL;
  78         return -1;
  79 }
  80
  81 // If socket is ready for reading parse netlink events
  82 static void handler_rtnl_event(struct uloop_fd *u, unsigned int events)
  83 {
  84         nl_recvmsgs(sock_rtnl_event, nl_cb_rtnl_event);
  85 }
  86
  87 // Evaluate netlink messages
  88 static int cb_rtnl_event(struct nl_msg *msg, void *arg)
  89 {
  90         struct nlmsghdr *nh = nlmsg_hdr(msg);
  91         struct ifinfomsg *ifi = NLMSG_DATA(nh);
  92         struct nlattr *nla[__IFLA_MAX];
  93
  94         if (nh->nlmsg_type != RTM_DELLINK && nh->nlmsg_type != RTM_NEWLINK)
  95                 goto out;
  96
  97         nlmsg_parse(nh, sizeof(*ifi), nla, __IFLA_MAX - 1, NULL);
  98         if (!nla[IFLA_IFNAME])
  99                 goto out;
 100
 101         struct device *dev = device_get(RTA_DATA(nla[IFLA_IFNAME]), false);
 102         if (!dev)
 103                 goto out;
 104
 105         dev->ifindex = ifi->ifi_index;
 106         device_set_present(dev, (nh->nlmsg_type == RTM_NEWLINK));
 107
 108 out:
 109         return 0;
 110 }
 111
 112 static int system_rtnl_call(struct nl_msg *msg)
 113 {
 114         int s = -(nl_send_auto_complete(sock_rtnl, msg)
 115                         || nl_wait_for_ack(sock_rtnl));
 116         nlmsg_free(msg);
 117         return s;
 118 }
 119
 120 int system_bridge_delbr(struct device *bridge)
 121 {
 122         return ioctl(sock_ioctl, SIOCBRDELBR, bridge->ifname);
 123 }
 124
 125 static int system_bridge_if(const char *bridge, struct device *dev, int cmd, void *data)
 126 {
 127         struct ifreq ifr;
 128         if (dev)
 129                 ifr.ifr_ifindex = dev->ifindex;
 130         else
 131                 ifr.ifr_data = data;
 132         strncpy(ifr.ifr_name, bridge, sizeof(ifr.ifr_name));
 133         return ioctl(sock_ioctl, cmd, &ifr);
 134 }
 135
 136 int system_bridge_addif(struct device *bridge, struct device *dev)
 137 {
 138         return system_bridge_if(bridge->ifname, dev, SIOCBRADDIF, NULL);
 139 }
 140
 141 int system_bridge_delif(struct device *bridge, struct device *dev)
 142 {
 143         return system_bridge_if(bridge->ifname, dev, SIOCBRDELIF, NULL);
 144 }
 145
 146 static bool system_is_bridge(const char *name, char *buf, int buflen)
 147 {
 148         struct stat st;
 149
 150         snprintf(buf, buflen, "/sys/devices/virtual/net/%s/bridge", name);
 151         if (stat(buf, &st) < 0)
 152                 return false;
 153
 154         return true;
 155 }
 156
 157 static char *system_get_bridge(const char *name, char *buf, int buflen)
 158 {
 159         char *path;
 160         ssize_t len;
 161         glob_t gl;
 162
 163         snprintf(buf, buflen, "/sys/devices/virtual/net/*/brif/%s/bridge", name);
 164         if (glob(buf, GLOB_NOSORT, NULL, &gl) < 0)
 165                 return NULL;
 166
 167         if (gl.gl_pathc == 0)
 168                 return NULL;
 169
 170         len = readlink(gl.gl_pathv[0], buf, buflen);
 171         if (len < 0)
 172                 return NULL;
 173
 174         buf[len] = 0;
 175         path = strrchr(buf, '/');
 176         if (!path)
 177                 return NULL;
 178
 179         return path + 1;
 180 }
 181
 182 static int system_if_resolve(struct device *dev)
 183 {
 184         struct ifreq ifr;
 185         strncpy(ifr.ifr_name, dev->ifname, sizeof(ifr.ifr_name));
 186         if (!ioctl(sock_ioctl, SIOCGIFINDEX, &ifr))
 187                 return ifr.ifr_ifindex;
 188         else
 189                 return 0;
 190 }
 191
 192 static int system_if_flags(const char *ifname, unsigned add, unsigned rem)
 193 {
 194         struct ifreq ifr;
 195         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 196         ioctl(sock_ioctl, SIOCGIFFLAGS, &ifr);
 197         ifr.ifr_flags |= add;
 198         ifr.ifr_flags &= ~rem;
 199         return ioctl(sock_ioctl, SIOCSIFFLAGS, &ifr);
 200 }
 201
 202 /*
 203  * Clear bridge (membership) state and bring down device
 204  */
 205 static void system_if_clear_state(struct device *dev)
 206 {
 207         char buf[256];
 208         char *bridge;
 209
 210         dev->ifindex = system_if_resolve(dev);
 211         if (!dev->ifindex)
 212                 return;
 213
 214         system_if_flags(dev->ifname, 0, IFF_UP);
 215
 216         if (system_is_bridge(dev->ifname, buf, sizeof(buf))) {
 217                 D(SYSTEM, "Delete existing bridge named '%s'\n", dev->ifname);
 218                 system_bridge_delbr(dev);
 219                 return;
 220         }
 221
 222         bridge = system_get_bridge(dev->ifname, buf, sizeof(buf));
 223         if (bridge) {
 224                 D(SYSTEM, "Remove device '%s' from bridge '%s'\n", dev->ifname, bridge);
 225                 system_bridge_if(bridge, dev, SIOCBRDELIF, NULL);
 226         }
 227 }
 228
 229 static inline unsigned long
 230 sec_to_jiffies(int val)
 231 {
 232         return (unsigned long) val * 100;
 233 }
 234
 235 int system_bridge_addbr(struct device *bridge, struct bridge_config *cfg)
 236 {
 237         unsigned long args[4] = {};
 238
 239         system_if_clear_state(bridge);
 240         if (ioctl(sock_ioctl, SIOCBRADDBR, bridge->ifname) < 0)
 241                 return -1;
 242
 243         args[0] = BRCTL_SET_BRIDGE_STP_STATE;
 244         args[1] = !!cfg->stp;
 245         system_bridge_if(bridge->ifname, NULL, SIOCDEVPRIVATE, &args);
 246
 247         args[0] = BRCTL_SET_BRIDGE_FORWARD_DELAY;
 248         args[1] = sec_to_jiffies(cfg->forward_delay);
 249         system_bridge_if(bridge->ifname, NULL, SIOCDEVPRIVATE, &args);
 250
 251         if (cfg->flags & BRIDGE_OPT_AGEING_TIME) {
 252                 args[0] = BRCTL_SET_AGEING_TIME;
 253                 args[1] = sec_to_jiffies(cfg->ageing_time);
 254                 system_bridge_if(bridge->ifname, NULL, SIOCDEVPRIVATE, &args);
 255         }
 256
 257         if (cfg->flags & BRIDGE_OPT_HELLO_TIME) {
 258                 args[0] = BRCTL_SET_BRIDGE_HELLO_TIME;
 259                 args[1] = sec_to_jiffies(cfg->hello_time);
 260                 system_bridge_if(bridge->ifname, NULL, SIOCDEVPRIVATE, &args);
 261         }
 262
 263         if (cfg->flags & BRIDGE_OPT_MAX_AGE) {
 264                 args[0] = BRCTL_SET_BRIDGE_MAX_AGE;
 265                 args[1] = sec_to_jiffies(cfg->max_age);
 266                 system_bridge_if(bridge->ifname, NULL, SIOCDEVPRIVATE, &args);
 267         }
 268
 269         return 0;
 270 }
 271
 272 static int system_vlan(struct device *dev, int id)
 273 {
 274         struct vlan_ioctl_args ifr = {
 275                 .cmd = SET_VLAN_NAME_TYPE_CMD,
 276                 .u.name_type = VLAN_NAME_TYPE_RAW_PLUS_VID_NO_PAD,
 277         };
 278
 279         ioctl(sock_ioctl, SIOCSIFVLAN, &ifr);
 280
 281         if (id < 0) {
 282                 ifr.cmd = DEL_VLAN_CMD;
 283                 ifr.u.VID = 0;
 284         } else {
 285                 ifr.cmd = ADD_VLAN_CMD;
 286                 ifr.u.VID = id;
 287         }
 288         strncpy(ifr.device1, dev->ifname, sizeof(ifr.device1));
 289         return ioctl(sock_ioctl, SIOCSIFVLAN, &ifr);
 290 }
 291
 292 int system_vlan_add(struct device *dev, int id)
 293 {
 294         system_if_clear_state(dev);
 295         return system_vlan(dev, id);
 296 }
 297
 298 int system_vlan_del(struct device *dev)
 299 {
 300         return system_vlan(dev, -1);
 301 }
 302
 303 int system_if_up(struct device *dev)
 304 {
 305         dev->ifindex = system_if_resolve(dev);
 306         return system_if_flags(dev->ifname, IFF_UP, 0);
 307 }
 308
 309 int system_if_down(struct device *dev)
 310 {
 311         return system_if_flags(dev->ifname, 0, IFF_UP);
 312 }
 313
 314 int system_if_check(struct device *dev)
 315 {
 316         system_if_clear_state(dev);
 317         device_set_present(dev, (system_if_resolve(dev) >= 0));
 318         return 0;
 319 }
 320
 321 static int system_addr(struct device *dev, struct device_addr *addr, int cmd)
 322 {
 323         int alen = ((addr->flags & DEVADDR_FAMILY) == DEVADDR_INET4) ? 4 : 16;
 324         struct ifaddrmsg ifa = {
 325                 .ifa_family = (alen == 4) ? AF_INET : AF_INET6,
 326                 .ifa_prefixlen = addr->mask,
 327                 .ifa_index = dev->ifindex,
 328         };
 329
 330         struct nl_msg *msg = nlmsg_alloc_simple(cmd, 0);
 331         if (!msg)
 332                 return -1;
 333
 334         nlmsg_append(msg, &ifa, sizeof(ifa), 0);
 335         nla_put(msg, IFA_LOCAL, alen, &addr->addr);
 336         return system_rtnl_call(msg);
 337 }
 338
 339 int system_add_address(struct device *dev, struct device_addr *addr)
 340 {
 341         return system_addr(dev, addr, RTM_NEWADDR);
 342 }
 343
 344 int system_del_address(struct device *dev, struct device_addr *addr)
 345 {
 346         return system_addr(dev, addr, RTM_DELADDR);
 347 }
 348
 349 static int system_rt(struct device *dev, struct device_route *route, int cmd)
 350 {
 351         int alen = ((route->flags & DEVADDR_FAMILY) == DEVADDR_INET4) ? 4 : 16;
 352         bool have_gw;
 353
 354         if (alen == 4)
 355                 have_gw = !!route->nexthop.in.s_addr;
 356         else
 357                 have_gw = route->nexthop.in6.s6_addr32[0] ||
 358                         route->nexthop.in6.s6_addr32[1] ||
 359                         route->nexthop.in6.s6_addr32[2] ||
 360                         route->nexthop.in6.s6_addr32[3];
 361
 362         unsigned char scope = (cmd == RTM_DELROUTE) ? RT_SCOPE_NOWHERE :
 363                         (have_gw) ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK;
 364
 365         struct rtmsg rtm = {
 366                 .rtm_family = (alen == 4) ? AF_INET : AF_INET6,
 367                 .rtm_dst_len = route->mask,
 368                 .rtm_table = RT_TABLE_MAIN,
 369                 .rtm_protocol = RTPROT_BOOT,
 370                 .rtm_scope = scope,
 371                 .rtm_type = (cmd == RTM_DELROUTE) ? 0: RTN_UNICAST,
 372         };
 373
 374         struct nl_msg *msg = nlmsg_alloc_simple(cmd, 0);
 375         if (!msg)
 376                 return -1;
 377
 378         nlmsg_append(msg, &rtm, sizeof(rtm), 0);
 379
 380         if (route->mask)
 381                 nla_put(msg, RTA_DST, alen, &route->addr);
 382
 383         if (have_gw)
 384                 nla_put(msg, RTA_GATEWAY, alen, &route->nexthop);
 385
 386         if (route->flags & DEVADDR_DEVICE)
 387                 nla_put_u32(msg, RTA_OIF, dev->ifindex);
 388
 389         return system_rtnl_call(msg);
 390 }
 391
 392 int system_add_route(struct device *dev, struct device_route *route)
 393 {
 394         return system_rt(dev, route, RTM_NEWROUTE);
 395 }
 396
 397 int system_del_route(struct device *dev, struct device_route *route)
 398 {
 399         return system_rt(dev, route, RTM_DELROUTE);
 400 }