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