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 <netlink/attr.h>
  13 #include <libubox/uloop.h>
  14
  15 #include "netifd.h"
  16 #include "device.h"
  17 #include "system.h"
  18
  19 static int sock_ioctl = -1;
  20 static struct nl_sock *sock_rtnl = NULL;
  21 static struct nl_sock *sock_rtnl_event = NULL;
  22
  23 static void handler_rtnl_event(struct uloop_fd *u, unsigned int events);
  24 static int cb_rtnl_event(struct nl_msg *msg, void *arg);
  25 static struct uloop_fd rtnl_event = {.cb = handler_rtnl_event};
  26 static struct nl_cb *nl_cb_rtnl_event;
  27
  28 int system_init(void)
  29 {
  30         sock_ioctl = socket(AF_LOCAL, SOCK_DGRAM, 0);
  31         fcntl(sock_ioctl, F_SETFD, fcntl(sock_ioctl, F_GETFD) | FD_CLOEXEC);
  32
  33         // Prepare socket for routing / address control
  34         if ((sock_rtnl = nl_socket_alloc())) {
  35                 if (nl_connect(sock_rtnl, NETLINK_ROUTE)) {
  36                         nl_socket_free(sock_rtnl);
  37                         sock_rtnl = NULL;
  38                 }
  39         }
  40
  41         // Prepare socket for link events
  42         if ((nl_cb_rtnl_event = nl_cb_alloc(NL_CB_DEFAULT)))
  43                 nl_cb_set(nl_cb_rtnl_event, NL_CB_VALID, NL_CB_CUSTOM,
  44                                                         cb_rtnl_event, NULL);
  45
  46         if (nl_cb_rtnl_event && (sock_rtnl_event = nl_socket_alloc())) {
  47                 if (nl_connect(sock_rtnl_event, NETLINK_ROUTE)) {
  48                         nl_socket_free(sock_rtnl_event);
  49                         sock_rtnl_event = NULL;
  50                 }
  51                 // Receive network link events form kernel
  52                 nl_socket_add_membership(sock_rtnl_event, RTNLGRP_LINK);
  53
  54                 // Synthesize initial link messages
  55                 struct nl_msg *m = nlmsg_alloc_simple(RTM_GETLINK, NLM_F_DUMP);
  56                 if (m && nlmsg_reserve(m, sizeof(struct ifinfomsg), 0)) {
  57                         nl_send_auto_complete(sock_rtnl_event, m);
  58                         nlmsg_free(m);
  59                 }
  60
  61 #ifdef NLA_PUT_DATA
  62                 rtnl_event.fd = nl_socket_get_fd(sock_rtnl_event);
  63 #else
  64                 rtnl_event.fd = sock_rtnl_event->s_fd; // libnl-tiny hack...
  65 #endif
  66                 uloop_fd_add(&rtnl_event, ULOOP_READ | ULOOP_EDGE_TRIGGER);
  67         }
  68
  69         return -(sock_ioctl < 0 || !sock_rtnl);
  70 }
  71
  72 // If socket is ready for reading parse netlink events
  73 static void handler_rtnl_event(struct uloop_fd *u, unsigned int events)
  74 {
  75         nl_recvmsgs(sock_rtnl_event, nl_cb_rtnl_event);
  76 }
  77
  78 // Evaluate netlink messages
  79 static int cb_rtnl_event(struct nl_msg *msg, void *arg)
  80 {
  81         struct nlmsghdr *nh = nlmsg_hdr(msg);
  82         struct ifinfomsg *ifi = NLMSG_DATA(nh);
  83         struct nlattr *nla[__IFLA_MAX];
  84
  85         if (nh->nlmsg_type != RTM_DELLINK && nh->nlmsg_type != RTM_NEWLINK)
  86                 goto out;
  87
  88         nlmsg_parse(nh, sizeof(*ifi), nla, __IFLA_MAX - 1, NULL);
  89         if (!nla[IFLA_IFNAME])
  90                 goto out;
  91
  92         struct device *dev = device_get(RTA_DATA(nla[IFLA_IFNAME]), false);
  93         if (!dev)
  94                 goto out;
  95
  96         dev->ifindex = ifi->ifi_index;
  97         device_set_present(dev, (nh->nlmsg_type == RTM_NEWLINK));
  98
  99 out:
 100         return 0;
 101 }
 102
 103 static int system_rtnl_call(struct nl_msg *msg)
 104 {
 105         int s = -(nl_send_auto_complete(sock_rtnl, msg)
 106                         || nl_wait_for_ack(sock_rtnl));
 107         nlmsg_free(msg);
 108         return s;
 109 }
 110
 111 int system_bridge_addbr(struct device *bridge)
 112 {
 113         return ioctl(sock_ioctl, SIOCBRADDBR, bridge->ifname);
 114 }
 115
 116 int system_bridge_delbr(struct device *bridge)
 117 {
 118         return ioctl(sock_ioctl, SIOCBRDELBR, bridge->ifname);
 119 }
 120
 121 static int system_bridge_if(struct device *bridge, struct device *dev, int cmd)
 122 {
 123         struct ifreq ifr;
 124         ifr.ifr_ifindex = dev->ifindex;
 125         strncpy(ifr.ifr_name, bridge->ifname, sizeof(ifr.ifr_name));
 126         return ioctl(sock_ioctl, cmd, &ifr);
 127 }
 128
 129 int system_bridge_addif(struct device *bridge, struct device *dev)
 130 {
 131         return system_bridge_if(bridge, dev, SIOCBRADDIF);
 132 }
 133
 134 int system_bridge_delif(struct device *bridge, struct device *dev)
 135 {
 136         return system_bridge_if(bridge, dev, SIOCBRDELIF);
 137 }
 138
 139 static int system_vlan(struct device *dev, int id)
 140 {
 141         struct vlan_ioctl_args ifr = {
 142                 .cmd = (id == 0) ? DEL_VLAN_CMD : ADD_VLAN_CMD,
 143                 .u = {.VID = id},
 144         };
 145         strncpy(ifr.device1, dev->ifname, sizeof(ifr.device1));
 146         return ioctl(sock_ioctl, SIOCSIFVLAN, &ifr);
 147 }
 148
 149 int system_vlan_add(struct device *dev, int id)
 150 {
 151         return system_vlan(dev, id);
 152 }
 153
 154 int system_vlan_del(struct device *dev)
 155 {
 156         return system_vlan(dev, 0);
 157 }
 158
 159 static int system_if_flags(struct device *dev, unsigned add, unsigned rem)
 160 {
 161         struct ifreq ifr;
 162         strncpy(ifr.ifr_name, dev->ifname, sizeof(ifr.ifr_name));
 163         ioctl(sock_ioctl, SIOCGIFFLAGS, &ifr);
 164         ifr.ifr_flags |= add;
 165         ifr.ifr_flags &= ~rem;
 166         return ioctl(sock_ioctl, SIOCSIFFLAGS, &ifr);
 167 }
 168
 169 static int system_if_resolve(struct device *dev)
 170 {
 171         struct ifreq ifr;
 172         strncpy(ifr.ifr_name, dev->ifname, sizeof(ifr.ifr_name));
 173         if (!ioctl(sock_ioctl, SIOCGIFINDEX, &ifr))
 174                 return ifr.ifr_ifindex;
 175         else
 176                 return 0;
 177 }
 178
 179 int system_if_up(struct device *dev)
 180 {
 181         dev->ifindex = system_if_resolve(dev);
 182         return system_if_flags(dev, IFF_UP, 0);
 183 }
 184
 185 int system_if_down(struct device *dev)
 186 {
 187         return system_if_flags(dev, 0, IFF_UP);
 188 }
 189
 190 int system_if_check(struct device *dev)
 191 {
 192         device_set_present(dev, (system_if_resolve(dev) >= 0));
 193         return 0;
 194 }
 195
 196 static int system_addr(struct device *dev, struct device_addr *addr, int cmd)
 197 {
 198         int alen = ((addr->flags & DEVADDR_FAMILY) == DEVADDR_INET4) ? 4 : 16;
 199         struct ifaddrmsg ifa = {
 200                 .ifa_family = (alen == 4) ? AF_INET : AF_INET6,
 201                 .ifa_prefixlen = addr->mask,
 202                 .ifa_index = dev->ifindex,
 203         };
 204
 205         struct nl_msg *msg = nlmsg_alloc_simple(cmd, 0);
 206         if (!msg)
 207                 return -1;
 208
 209         nlmsg_append(msg, &ifa, sizeof(ifa), 0);
 210         nla_put(msg, IFA_LOCAL, alen, &addr->addr);
 211         return system_rtnl_call(msg);
 212 }
 213
 214 int system_add_address(struct device *dev, struct device_addr *addr)
 215 {
 216         return system_addr(dev, addr, RTM_NEWADDR);
 217 }
 218
 219 int system_del_address(struct device *dev, struct device_addr *addr)
 220 {
 221         return system_addr(dev, addr, RTM_DELADDR);
 222 }
 223
 224 static int system_rt(struct device *dev, struct device_route *route, int cmd)
 225 {
 226         int alen = ((route->flags & DEVADDR_FAMILY) == DEVADDR_INET4) ? 4 : 16;
 227         bool have_gw;
 228
 229         if (alen == 4)
 230                 have_gw = !!route->nexthop.in.s_addr;
 231         else
 232                 have_gw = route->nexthop.in6.s6_addr32[0] ||
 233                         route->nexthop.in6.s6_addr32[1] ||
 234                         route->nexthop.in6.s6_addr32[2] ||
 235                         route->nexthop.in6.s6_addr32[3];
 236
 237         unsigned char scope = (cmd == RTM_DELROUTE) ? RT_SCOPE_NOWHERE :
 238                         (have_gw) ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK;
 239
 240         struct rtmsg rtm = {
 241                 .rtm_family = (alen == 4) ? AF_INET : AF_INET6,
 242                 .rtm_dst_len = route->mask,
 243                 .rtm_table = RT_TABLE_MAIN,
 244                 .rtm_protocol = RTPROT_BOOT,
 245                 .rtm_scope = scope,
 246                 .rtm_type = (cmd == RTM_DELROUTE) ? 0: RTN_UNICAST,
 247         };
 248
 249         struct nl_msg *msg = nlmsg_alloc_simple(cmd, 0);
 250         if (!msg)
 251                 return -1;
 252
 253         nlmsg_append(msg, &rtm, sizeof(rtm), 0);
 254
 255         if (route->mask)
 256                 nla_put(msg, RTA_DST, alen, &route->addr);
 257
 258         if (have_gw)
 259                 nla_put(msg, RTA_GATEWAY, alen, &route->nexthop);
 260
 261         if (route->flags & DEVADDR_DEVICE)
 262                 nla_put_u32(msg, RTA_OIF, dev->ifindex);
 263
 264         return system_rtnl_call(msg);
 265 }
 266
 267 int system_add_route(struct device *dev, struct device_route *route)
 268 {
 269         return system_rt(dev, route, RTM_NEWROUTE);
 270 }
 271
 272 int system_del_route(struct device *dev, struct device_route *route)
 273 {
 274         return system_rt(dev, route, RTM_DELROUTE);
 275 }