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