system-linux.c

   1 #include <sys/socket.h>
   2 #include <sys/ioctl.h>
   3 #include <sys/stat.h>
   4 #include <sys/syscall.h>
   5
   6 #include <linux/rtnetlink.h>
   7 #include <linux/sockios.h>
   8 #include <linux/if_vlan.h>
   9 #include <linux/if_bridge.h>
  10
  11 #include <unistd.h>
  12 #include <string.h>
  13 #include <fcntl.h>
  14 #include <glob.h>
  15
  16 #include <netlink/msg.h>
  17 #include <netlink/attr.h>
  18 #include <netlink/socket.h>
  19 #include <libubox/uloop.h>
  20
  21 #include "netifd.h"
  22 #include "device.h"
  23 #include "system.h"
  24
  25 static int sock_ioctl = -1;
  26 static struct nl_sock *sock_rtnl = NULL;
  27 static struct nl_sock *sock_rtnl_event = NULL;
  28
  29 static void handler_rtnl_event(struct uloop_fd *u, unsigned int events);
  30 static int cb_rtnl_event(struct nl_msg *msg, void *arg);
  31 static struct uloop_fd rtnl_event = {.cb = handler_rtnl_event};
  32 static struct nl_cb *nl_cb_rtnl_event;
  33
  34 int system_init(void)
  35 {
  36         sock_ioctl = socket(AF_LOCAL, SOCK_DGRAM, 0);
  37         fcntl(sock_ioctl, F_SETFD, fcntl(sock_ioctl, F_GETFD) | FD_CLOEXEC);
  38
  39         // Prepare socket for routing / address control
  40         sock_rtnl = nl_socket_alloc();
  41         if (!sock_rtnl)
  42                 return -1;
  43
  44         if (nl_connect(sock_rtnl, NETLINK_ROUTE))
  45                 goto error_free_sock;
  46
  47         // Prepare socket for link events
  48         nl_cb_rtnl_event = nl_cb_alloc(NL_CB_DEFAULT);
  49         if (!nl_cb_rtnl_event)
  50                 goto error_free_sock;
  51
  52         nl_cb_set(nl_cb_rtnl_event, NL_CB_VALID, NL_CB_CUSTOM,
  53                   cb_rtnl_event, NULL);
  54
  55         sock_rtnl_event = nl_socket_alloc();
  56         if (!sock_rtnl_event)
  57                 goto error_free_cb;
  58
  59         if (nl_connect(sock_rtnl_event, NETLINK_ROUTE))
  60                 goto error_free_event;
  61
  62         // Receive network link events form kernel
  63         nl_socket_add_membership(sock_rtnl_event, RTNLGRP_LINK);
  64
  65         rtnl_event.fd = nl_socket_get_fd(sock_rtnl_event);
  66         uloop_fd_add(&rtnl_event, ULOOP_READ | ULOOP_EDGE_TRIGGER);
  67
  68         return 0;
  69
  70 error_free_event:
  71         nl_socket_free(sock_rtnl_event);
  72         sock_rtnl_event = NULL;
  73 error_free_cb:
  74         nl_cb_put(nl_cb_rtnl_event);
  75         nl_cb_rtnl_event = NULL;
  76 error_free_sock:
  77         nl_socket_free(sock_rtnl);
  78         sock_rtnl = NULL;
  79         return -1;
  80 }
  81
  82 // If socket is ready for reading parse netlink events
  83 static void handler_rtnl_event(struct uloop_fd *u, unsigned int events)
  84 {
  85         nl_recvmsgs(sock_rtnl_event, nl_cb_rtnl_event);
  86 }
  87
  88 // Evaluate netlink messages
  89 static int cb_rtnl_event(struct nl_msg *msg, void *arg)
  90 {
  91         struct nlmsghdr *nh = nlmsg_hdr(msg);
  92         struct ifinfomsg *ifi = NLMSG_DATA(nh);
  93         struct nlattr *nla[__IFLA_MAX];
  94
  95         if (nh->nlmsg_type != RTM_DELLINK && nh->nlmsg_type != RTM_NEWLINK)
  96                 goto out;
  97
  98         nlmsg_parse(nh, sizeof(*ifi), nla, __IFLA_MAX - 1, NULL);
  99         if (!nla[IFLA_IFNAME])
 100                 goto out;
 101
 102         struct device *dev = device_get(RTA_DATA(nla[IFLA_IFNAME]), false);
 103         if (!dev)
 104                 goto out;
 105
 106         dev->ifindex = ifi->ifi_index;
 107         device_set_present(dev, (nh->nlmsg_type == RTM_NEWLINK));
 108
 109 out:
 110         return 0;
 111 }
 112
 113 static int system_rtnl_call(struct nl_msg *msg)
 114 {
 115         int s = -(nl_send_auto_complete(sock_rtnl, msg)
 116                         || nl_wait_for_ack(sock_rtnl));
 117         nlmsg_free(msg);
 118         return s;
 119 }
 120
 121 int system_bridge_delbr(struct device *bridge)
 122 {
 123         return ioctl(sock_ioctl, SIOCBRDELBR, bridge->ifname);
 124 }
 125
 126 static int system_bridge_if(const char *bridge, struct device *dev, int cmd, void *data)
 127 {
 128         struct ifreq ifr;
 129         if (dev)
 130                 ifr.ifr_ifindex = dev->ifindex;
 131         else
 132                 ifr.ifr_data = data;
 133         strncpy(ifr.ifr_name, bridge, sizeof(ifr.ifr_name));
 134         return ioctl(sock_ioctl, cmd, &ifr);
 135 }
 136
 137 int system_bridge_addif(struct device *bridge, struct device *dev)
 138 {
 139         return system_bridge_if(bridge->ifname, dev, SIOCBRADDIF, NULL);
 140 }
 141
 142 int system_bridge_delif(struct device *bridge, struct device *dev)
 143 {
 144         return system_bridge_if(bridge->ifname, dev, SIOCBRDELIF, NULL);
 145 }
 146
 147 static bool system_is_bridge(const char *name, char *buf, int buflen)
 148 {
 149         struct stat st;
 150
 151         snprintf(buf, buflen, "/sys/devices/virtual/net/%s/bridge", name);
 152         if (stat(buf, &st) < 0)
 153                 return false;
 154
 155         return true;
 156 }
 157
 158 static char *system_get_bridge(const char *name, char *buf, int buflen)
 159 {
 160         char *path;
 161         ssize_t len;
 162         glob_t gl;
 163
 164         snprintf(buf, buflen, "/sys/devices/virtual/net/*/brif/%s/bridge", name);
 165         if (glob(buf, GLOB_NOSORT, NULL, &gl) < 0)
 166                 return NULL;
 167
 168         if (gl.gl_pathc == 0)
 169                 return NULL;
 170
 171         len = readlink(gl.gl_pathv[0], buf, buflen);
 172         if (len < 0)
 173                 return NULL;
 174
 175         buf[len] = 0;
 176         path = strrchr(buf, '/');
 177         if (!path)
 178                 return NULL;
 179
 180         return path + 1;
 181 }
 182
 183 static int system_if_resolve(struct device *dev)
 184 {
 185         struct ifreq ifr;
 186         strncpy(ifr.ifr_name, dev->ifname, sizeof(ifr.ifr_name));
 187         if (!ioctl(sock_ioctl, SIOCGIFINDEX, &ifr))
 188                 return ifr.ifr_ifindex;
 189         else
 190                 return 0;
 191 }
 192
 193 static int system_if_flags(const char *ifname, unsigned add, unsigned rem)
 194 {
 195         struct ifreq ifr;
 196         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 197         ioctl(sock_ioctl, SIOCGIFFLAGS, &ifr);
 198         ifr.ifr_flags |= add;
 199         ifr.ifr_flags &= ~rem;
 200         return ioctl(sock_ioctl, SIOCSIFFLAGS, &ifr);
 201 }
 202
 203 /*
 204  * Clear bridge (membership) state and bring down device
 205  */
 206 void system_if_clear_state(struct device *dev)
 207 {
 208         char buf[256];
 209         char *bridge;
 210
 211         dev->ifindex = system_if_resolve(dev);
 212         if (!dev->ifindex)
 213                 return;
 214
 215         system_if_flags(dev->ifname, 0, IFF_UP);
 216
 217         if (system_is_bridge(dev->ifname, buf, sizeof(buf))) {
 218                 D(SYSTEM, "Delete existing bridge named '%s'\n", dev->ifname);
 219                 system_bridge_delbr(dev);
 220                 return;
 221         }
 222
 223         bridge = system_get_bridge(dev->ifname, buf, sizeof(buf));
 224         if (bridge) {
 225                 D(SYSTEM, "Remove device '%s' from bridge '%s'\n", dev->ifname, bridge);
 226                 system_bridge_if(bridge, dev, SIOCBRDELIF, NULL);
 227         }
 228 }
 229
 230 static inline unsigned long
 231 sec_to_jiffies(int val)
 232 {
 233         return (unsigned long) val * 100;
 234 }
 235
 236 int system_bridge_addbr(struct device *bridge, struct bridge_config *cfg)
 237 {
 238         unsigned long args[4] = {};
 239
 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         return system_vlan(dev, id);
 295 }
 296
 297 int system_vlan_del(struct device *dev)
 298 {
 299         return system_vlan(dev, -1);
 300 }
 301
 302 int system_if_up(struct device *dev)
 303 {
 304         dev->ifindex = system_if_resolve(dev);
 305         return system_if_flags(dev->ifname, IFF_UP, 0);
 306 }
 307
 308 int system_if_down(struct device *dev)
 309 {
 310         return system_if_flags(dev->ifname, 0, IFF_UP);
 311 }
 312
 313 int system_if_check(struct device *dev)
 314 {
 315         device_set_present(dev, (system_if_resolve(dev) >= 0));
 316         return 0;
 317 }
 318
 319 static int system_addr(struct device *dev, struct device_addr *addr, int cmd)
 320 {
 321         int alen = ((addr->flags & DEVADDR_FAMILY) == DEVADDR_INET4) ? 4 : 16;
 322         struct ifaddrmsg ifa = {
 323                 .ifa_family = (alen == 4) ? AF_INET : AF_INET6,
 324                 .ifa_prefixlen = addr->mask,
 325                 .ifa_index = dev->ifindex,
 326         };
 327
 328         struct nl_msg *msg = nlmsg_alloc_simple(cmd, 0);
 329         if (!msg)
 330                 return -1;
 331
 332         nlmsg_append(msg, &ifa, sizeof(ifa), 0);
 333         nla_put(msg, IFA_LOCAL, alen, &addr->addr);
 334         return system_rtnl_call(msg);
 335 }
 336
 337 int system_add_address(struct device *dev, struct device_addr *addr)
 338 {
 339         return system_addr(dev, addr, RTM_NEWADDR);
 340 }
 341
 342 int system_del_address(struct device *dev, struct device_addr *addr)
 343 {
 344         return system_addr(dev, addr, RTM_DELADDR);
 345 }
 346
 347 static int system_rt(struct device *dev, struct device_route *route, int cmd)
 348 {
 349         int alen = ((route->flags & DEVADDR_FAMILY) == DEVADDR_INET4) ? 4 : 16;
 350         bool have_gw;
 351
 352         if (alen == 4)
 353                 have_gw = !!route->nexthop.in.s_addr;
 354         else
 355                 have_gw = route->nexthop.in6.s6_addr32[0] ||
 356                         route->nexthop.in6.s6_addr32[1] ||
 357                         route->nexthop.in6.s6_addr32[2] ||
 358                         route->nexthop.in6.s6_addr32[3];
 359
 360         unsigned char scope = (cmd == RTM_DELROUTE) ? RT_SCOPE_NOWHERE :
 361                         (have_gw) ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK;
 362
 363         struct rtmsg rtm = {
 364                 .rtm_family = (alen == 4) ? AF_INET : AF_INET6,
 365                 .rtm_dst_len = route->mask,
 366                 .rtm_table = RT_TABLE_MAIN,
 367                 .rtm_protocol = RTPROT_BOOT,
 368                 .rtm_scope = scope,
 369                 .rtm_type = (cmd == RTM_DELROUTE) ? 0: RTN_UNICAST,
 370         };
 371
 372         struct nl_msg *msg = nlmsg_alloc_simple(cmd, 0);
 373         if (!msg)
 374                 return -1;
 375
 376         nlmsg_append(msg, &rtm, sizeof(rtm), 0);
 377
 378         if (route->mask)
 379                 nla_put(msg, RTA_DST, alen, &route->addr);
 380
 381         if (have_gw)
 382                 nla_put(msg, RTA_GATEWAY, alen, &route->nexthop);
 383
 384         if (route->flags & DEVADDR_DEVICE)
 385                 nla_put_u32(msg, RTA_OIF, dev->ifindex);
 386
 387         return system_rtnl_call(msg);
 388 }
 389
 390 int system_add_route(struct device *dev, struct device_route *route)
 391 {
 392         return system_rt(dev, route, RTM_NEWROUTE);
 393 }
 394
 395 int system_del_route(struct device *dev, struct device_route *route)
 396 {
 397         return system_rt(dev, route, RTM_DELROUTE);
 398 }
 399
 400 time_t system_get_rtime(void)
 401 {
 402         struct timespec ts;
 403         struct timeval tv;
 404
 405         if (syscall(__NR_clock_gettime, CLOCK_MONOTONIC, &ts) == 0)
 406                 return ts.tv_sec;
 407
 408         if (gettimeofday(&tv, NULL) == 0)
 409                 return tv.tv_sec;
 410
 411         return 0;
 412 }