system-linux.c

   1 #include <sys/socket.h>
   2 #include <sys/ioctl.h>
   3
   4 #include <linux/rtnetlink.h>
   5 #include <linux/sockios.h>
   6 #include <linux/if_vlan.h>
   7
   8 #include <string.h>
   9 #include <fcntl.h>
  10
  11 #include <netlink/msg.h>
  12 #include <libubox/uloop.h>
  13
  14 #include "netifd.h"
  15 #include "device.h"
  16 #include "system.h"
  17
  18 static int sock_ioctl = -1;
  19 static struct nl_sock *sock_rtnl = NULL;
  20 static struct nl_sock *sock_rtnl_event = NULL;
  21
  22 static void handler_rtnl_event(struct uloop_fd *u, unsigned int events);
  23 static int cb_rtnl_event(struct nl_msg *msg, void *arg);
  24 static struct uloop_fd rtnl_event = {.cb = handler_rtnl_event};
  25
  26 int system_init(void)
  27 {
  28         sock_ioctl = socket(AF_LOCAL, SOCK_DGRAM, 0);
  29         fcntl(sock_ioctl, F_SETFD, fcntl(sock_ioctl, F_GETFD) | FD_CLOEXEC);
  30
  31         // Prepare socket for routing / address control
  32         if ((sock_rtnl = nl_socket_alloc())) {
  33                 if (nl_connect(sock_rtnl, NETLINK_ROUTE)) {
  34                         nl_socket_free(sock_rtnl);
  35                         sock_rtnl = NULL;
  36                 }
  37         }
  38
  39         // Prepare socket for link events
  40         struct nl_cb *cb = nl_cb_alloc(NL_CB_DEFAULT);
  41         if (cb)
  42                 nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, cb_rtnl_event, NULL);
  43
  44         if (cb && (sock_rtnl_event = nl_socket_alloc_cb(cb))) {
  45                 if (nl_connect(sock_rtnl_event, NETLINK_ROUTE)) {
  46                         nl_socket_free(sock_rtnl_event);
  47                         sock_rtnl_event = NULL;
  48                 }
  49                 // Receive network link events form kernel
  50                 nl_socket_add_membership(sock_rtnl_event, RTNLGRP_LINK);
  51
  52                 // Synthesize initial link messages
  53                 struct nl_msg *m = nlmsg_alloc_simple(RTM_GETLINK, NLM_F_DUMP);
  54                 if (m && nlmsg_reserve(m, sizeof(struct ifinfomsg), 0)) {
  55                         nl_send_auto_complete(sock_rtnl_event, m);
  56                         nlmsg_free(m);
  57                 }
  58
  59 #ifdef NLA_PUT_DATA
  60                 rtnl_event.fd = nl_socket_get_fd(sock_rtnl_event);
  61 #else
  62                 rtnl_event.fd = sock_rtnl_event->s_fd; // libnl-tiny hack...
  63 #endif
  64                 uloop_fd_add(&rtnl_event, ULOOP_READ | ULOOP_EDGE_TRIGGER);
  65         }
  66
  67         return -(sock_ioctl < 0 || !sock_rtnl);
  68 }
  69
  70 // If socket is ready for reading parse netlink events
  71 static void handler_rtnl_event(struct uloop_fd *u, unsigned int events)
  72 {
  73         nl_recvmsgs(sock_rtnl_event, NULL);
  74 }
  75
  76 // Evaluate netlink messages
  77 static int cb_rtnl_event(struct nl_msg *msg, void *arg)
  78 {
  79         struct nlmsghdr *nh = nlmsg_hdr(msg);
  80         struct ifinfomsg *ifi = NLMSG_DATA(nh);
  81         struct nlattr *nla[__IFLA_MAX];
  82
  83         if (nh->nlmsg_type != RTM_DELLINK && nh->nlmsg_type != RTM_NEWLINK)
  84                 goto out;
  85
  86         nlmsg_parse(nh, sizeof(*ifi), nla, __IFLA_MAX - 1, NULL);
  87         if (!nla[IFLA_IFNAME])
  88                 goto out;
  89
  90         struct device *dev = device_get(RTA_DATA(nla[IFLA_IFNAME]), false);
  91         if (!dev)
  92                 goto out;
  93
  94         dev->ifindex = ifi->ifi_index;
  95         device_set_present(dev, (nh->nlmsg_type == RTM_NEWLINK));
  96
  97 out:
  98         return 0;
  99 }
 100
 101 static int system_rtnl_call(struct nl_msg *msg)
 102 {
 103         int s = -(nl_send_auto_complete(sock_rtnl, msg)
 104                         || nl_wait_for_ack(sock_rtnl));
 105         nlmsg_free(msg);
 106         return s;
 107 }
 108
 109 int system_bridge_addbr(struct device *bridge)
 110 {
 111         return ioctl(sock_ioctl, SIOCBRADDBR, bridge->ifname);
 112 }
 113
 114 int system_bridge_delbr(struct device *bridge)
 115 {
 116         return ioctl(sock_ioctl, SIOCBRDELBR, bridge->ifname);
 117 }
 118
 119 static int system_bridge_if(struct device *bridge, struct device *dev, int cmd)
 120 {
 121         struct ifreq ifr;
 122         ifr.ifr_ifindex = dev->ifindex;
 123         strncpy(ifr.ifr_name, bridge->ifname, sizeof(ifr.ifr_name));
 124         return ioctl(sock_ioctl, cmd, &ifr);
 125 }
 126
 127 int system_bridge_addif(struct device *bridge, struct device *dev)
 128 {
 129         return system_bridge_if(bridge, dev, SIOCBRADDIF);
 130 }
 131
 132 int system_bridge_delif(struct device *bridge, struct device *dev)
 133 {
 134         return system_bridge_if(bridge, dev, SIOCBRDELIF);
 135 }
 136
 137 static int system_vlan(struct device *dev, int id)
 138 {
 139         struct vlan_ioctl_args ifr = {
 140                 .cmd = (id == 0) ? DEL_VLAN_CMD : ADD_VLAN_CMD,
 141                 .u = {.VID = id},
 142         };
 143         strncpy(ifr.device1, dev->ifname, sizeof(ifr.device1));
 144         return ioctl(sock_ioctl, SIOCSIFVLAN, &ifr);
 145 }
 146
 147 int system_vlan_add(struct device *dev, int id)
 148 {
 149         return system_vlan(dev, id);
 150 }
 151
 152 int system_vlan_del(struct device *dev)
 153 {
 154         return system_vlan(dev, 0);
 155 }
 156
 157 static int system_if_flags(struct device *dev, unsigned add, unsigned rem)
 158 {
 159         struct ifreq ifr;
 160         strncpy(ifr.ifr_name, dev->ifname, sizeof(ifr.ifr_name));
 161         ioctl(sock_ioctl, SIOCGIFFLAGS, &ifr);
 162         ifr.ifr_flags |= add;
 163         ifr.ifr_flags &= ~rem;
 164         return ioctl(sock_ioctl, SIOCSIFFLAGS, &ifr);
 165 }
 166
 167 int system_if_up(struct device *dev)
 168 {
 169         return system_if_flags(dev, IFF_UP, 0);
 170 }
 171
 172 int system_if_down(struct device *dev)
 173 {
 174         return system_if_flags(dev, 0, IFF_UP);
 175 }
 176
 177 int system_if_check(struct device *dev)
 178 {
 179         struct ifreq ifr;
 180         strncpy(ifr.ifr_name, dev->ifname, sizeof(ifr.ifr_name));
 181         if (ioctl(sock_ioctl, SIOCGIFINDEX, &ifr))
 182                 return -1;
 183
 184         dev->ifindex = ifr.ifr_ifindex;
 185
 186         /* if (!strcmp(dev->ifname, "eth0"))
 187                 device_set_present(dev, true); */
 188         return 0;
 189 }
 190
 191 static int system_addr(struct device *dev, struct device_addr *addr, int cmd)
 192 {
 193         int alen = ((addr->flags & DEVADDR_FAMILY) == DEVADDR_INET4) ? 4 : 16;
 194         struct ifaddrmsg ifa = {
 195                 .ifa_family = (alen == 4) ? AF_INET : AF_INET6,
 196                 .ifa_prefixlen = addr->mask,
 197                 .ifa_index = dev->ifindex,
 198         };
 199
 200         struct nl_msg *msg = nlmsg_alloc_simple(cmd, 0);
 201         if (!msg)
 202                 return -1;
 203
 204         nlmsg_append(msg, &ifa, sizeof(ifa), 0);
 205         nla_put(msg, IFA_ADDRESS, alen, &addr->addr);
 206         return system_rtnl_call(msg);
 207 }
 208
 209 int system_add_address(struct device *dev, struct device_addr *addr)
 210 {
 211         return system_addr(dev, addr, RTM_NEWADDR);
 212 }
 213
 214 int system_del_address(struct device *dev, struct device_addr *addr)
 215 {
 216         return system_addr(dev, addr, RTM_DELADDR);
 217 }
 218
 219 static int system_rt(struct device *dev, struct device_route *route, int cmd)
 220 {
 221         int alen = ((route->flags & DEVADDR_FAMILY) == DEVADDR_INET4) ? 4 : 16;
 222         bool have_gw;
 223
 224         if (alen == 4)
 225                 have_gw = !!route->nexthop.in.s_addr;
 226         else
 227                 have_gw = route->nexthop.in6.s6_addr32[0] ||
 228                         route->nexthop.in6.s6_addr32[1] ||
 229                         route->nexthop.in6.s6_addr32[2] ||
 230                         route->nexthop.in6.s6_addr32[3];
 231
 232         unsigned char scope = (cmd == RTM_DELROUTE) ? RT_SCOPE_NOWHERE :
 233                         (have_gw) ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK;
 234
 235         struct rtmsg rtm = {
 236                 .rtm_family = (alen == 4) ? AF_INET : AF_INET6,
 237                 .rtm_dst_len = route->mask,
 238                 .rtm_table = RT_TABLE_MAIN,
 239                 .rtm_protocol = RTPROT_BOOT,
 240                 .rtm_scope = scope,
 241                 .rtm_type = (cmd == RTM_DELROUTE) ? 0: RTN_UNICAST,
 242         };
 243
 244         struct nl_msg *msg = nlmsg_alloc_simple(cmd, 0);
 245         if (!msg)
 246                 return -1;
 247
 248         nlmsg_append(msg, &rtm, sizeof(rtm), 0);
 249
 250         if (route->mask)
 251                 nla_put(msg, RTA_DST, alen, &route->addr);
 252
 253         if (have_gw)
 254                 nla_put(msg, RTA_GATEWAY, alen, &route->nexthop);
 255
 256         if (route->flags & DEVADDR_DEVICE)
 257                 nla_put_u32(msg, RTA_OIF, dev->ifindex);
 258
 259         return system_rtnl_call(msg);
 260 }
 261
 262 int system_add_route(struct device *dev, struct device_route *route)
 263 {
 264         return system_rt(dev, route, RTM_NEWROUTE);
 265 }
 266
 267 int system_del_route(struct device *dev, struct device_route *route)
 268 {
 269         return system_rt(dev, route, RTM_DELROUTE);
 270 }