kernel-netlink: Implement enumerator for local subnets

diff --git a/src/libcharon/plugins/kernel_netlink/kernel_netlink_net.c b/src/libcharon/plugins/kernel_netlink/kernel_netlink_net.c
index 4ecd97634d41b06e344ef5632a8e866f6c07217f..a31f312b98afa935194e30fb5c50cb3dec4cc3f0 100644 (file)
--- a/src/libcharon/plugins/kernel_netlink/kernel_netlink_net.c
+++ b/src/libcharon/plugins/kernel_netlink/kernel_netlink_net.c
@@ -2125,6 +2125,135 @@ METHOD(kernel_net_t, get_nexthop, host_t*,
        return get_route(this, dest, prefix, TRUE, src, iface, 0);
 }
 
+/** enumerator over subnets */
+typedef struct {
+       enumerator_t public;
+       private_kernel_netlink_net_t *private;
+       /** message from the kernel */
+       struct nlmsghdr *msg;
+       /** current message from the kernel */
+       struct nlmsghdr *current;
+       /** remaining length */
+       size_t len;
+       /** last subnet enumerated */
+       host_t *net;
+} subnet_enumerator_t;
+
+METHOD(enumerator_t, destroy_subnet_enumerator, void,
+       subnet_enumerator_t *this)
+{
+       DESTROY_IF(this->net);
+       free(this->msg);
+       free(this);
+}
+
+METHOD(enumerator_t, enumerate_subnets, bool,
+       subnet_enumerator_t *this, host_t **net, uint8_t *mask)
+{
+       if (!this->current)
+       {
+               this->current = this->msg;
+       }
+       else
+       {
+               this->current = NLMSG_NEXT(this->current, this->len);
+               DESTROY_IF(this->net);
+               this->net = NULL;
+       }
+
+       while (NLMSG_OK(this->current, this->len))
+       {
+               switch (this->current->nlmsg_type)
+               {
+                       case NLMSG_DONE:
+                               break;
+                       case RTM_NEWROUTE:
+                       {
+                               struct rtmsg *msg;
+                               struct rtattr *rta;
+                               size_t rtasize;
+                               chunk_t dst = chunk_empty;
+
+                               msg = NLMSG_DATA(this->current);
+
+                               if (!route_usable(this->current))
+                               {
+                                       break;
+                               }
+                               else if (msg->rtm_table && (
+                                                       msg->rtm_table == RT_TABLE_LOCAL ||
+                                                       msg->rtm_table == this->private->routing_table))
+                               {       /* ignore our own and the local routing tables */
+                                       break;
+                               }
+
+                               rta = RTM_RTA(msg);
+                               rtasize = RTM_PAYLOAD(this->current);
+                               while (RTA_OK(rta, rtasize))
+                               {
+                                       if (rta->rta_type == RTA_DST)
+                                       {
+                                               dst = chunk_create(RTA_DATA(rta), RTA_PAYLOAD(rta));
+                                               break;
+                                       }
+                                       rta = RTA_NEXT(rta, rtasize);
+                               }
+
+                               if (dst.ptr)
+                               {
+                                       this->net = host_create_from_chunk(msg->rtm_family, dst, 0);
+                                       *net = this->net;
+                                       *mask = msg->rtm_dst_len;
+                                       return TRUE;
+                               }
+                               break;
+                       }
+                       default:
+                               break;
+               }
+               this->current = NLMSG_NEXT(this->current, this->len);
+       }
+       return FALSE;
+}
+
+METHOD(kernel_net_t, create_local_subnet_enumerator, enumerator_t*,
+       private_kernel_netlink_net_t *this)
+{
+       netlink_buf_t request;
+       struct nlmsghdr *hdr, *out;
+       struct rtmsg *msg;
+       size_t len;
+       subnet_enumerator_t *enumerator;
+
+       memset(&request, 0, sizeof(request));
+
+       hdr = &request.hdr;
+       hdr->nlmsg_flags = NLM_F_REQUEST;
+       hdr->nlmsg_type = RTM_GETROUTE;
+       hdr->nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
+       hdr->nlmsg_flags |= NLM_F_DUMP;
+
+       msg = NLMSG_DATA(hdr);
+       msg->rtm_scope = RT_SCOPE_LINK;
+
+       if (this->socket->send(this->socket, hdr, &out, &len) != SUCCESS)
+       {
+               DBG2(DBG_KNL, "enumerating local subnets failed");
+               return enumerator_create_empty();
+       }
+
+       INIT(enumerator,
+               .public = {
+                       .enumerate = (void*)_enumerate_subnets,
+                       .destroy = _destroy_subnet_enumerator,
+               },
+               .private = this,
+               .msg = out,
+               .len = len,
+       );
+       return &enumerator->public;
+}
+
 /**
  * Manages the creation and deletion of ip addresses on an interface.
  * By setting the appropriate nlmsg_type, the ip will be set or unset.
@@ -2761,6 +2890,7 @@ kernel_netlink_net_t *kernel_netlink_net_create()
                        .interface = {
                                .get_interface = _get_interface_name,
                                .create_address_enumerator = _create_address_enumerator,
+                               .create_local_subnet_enumerator = _create_local_subnet_enumerator,
                                .get_source_addr = _get_source_addr,
                                .get_nexthop = _get_nexthop,
                                .add_ip = _add_ip,