/**
* Create a netlink socket and connect to it kernel.
* @arg handle netlink handle
* @arg protocol desired netlink protocol
*
* Creates a netlink socket of the desired \c protocol and connects it
* to the kernel.
*
* @note nl_handle::local::nl_groups may contain a multicast group mask.
* @exception EADDRNOTAVAIL Invalid address length
* @exception EPFNOSUPPORT Address format not supported
*/
int nl_connect(struct nl_handle *handle, int protocol)
{
int err;
socklen_t addrlen;
nl_init_handle(handle);
if ((handle->h_fd = socket(AF_NETLINK, SOCK_RAW, protocol)) < 0)
return nl_error(1, "socket(AF_NETLINK, ...) failed");
if ((err = nl_set_buffer_size(handle, 0, 0)) < 0)
return err;
err = bind(handle->h_fd, (struct sockaddr*) &handle->h_local,
sizeof(handle->h_local));
if (err < 0)
return nl_error(1, "bind() failed");
addrlen = sizeof(handle->h_local);
err = getsockname(handle->h_fd, (struct sockaddr *) &handle->h_local,
&addrlen);
if (err < 0)
return nl_error(1, "getsockname failed");
if (addrlen != sizeof(handle->h_local))
return nl_error(EADDRNOTAVAIL, "Invalid address length");
if (handle->h_local.nl_family != AF_NETLINK)
return nl_error(EPFNOSUPPORT, "Address format not supported");
return 0;
}
static inline int nl_socket_set_buffer_size(struct nl_sock *sk,
int rxbuf, int txbuf)
{
return nl_set_buffer_size(sk, rxbuf, txbuf);
}
/**
* Setups generic netlink connection with the kernel module and retrieves assocaited family id
*
* @return 0 on success
*/
static int initialize_netlink_family(void) {
struct nl_handle* hndl;
struct nl_msg* msg = NULL;
struct nl_msg *ans_msg = NULL;
struct nlmsghdr *nl_hdr;
struct genlmsghdr* genl_hdr;
struct nlattr *nla;
int ret_val = 0;
hndl = nl_handle_alloc();
nl_set_buffer_size(hndl, 15000000, 15000000);
//nl_handle_set_peer_pid(hndl, 0);
//nl_set_passcred(hndl, 1);
nl_disable_sequence_check(hndl);
if ( (ret_val=nl_connect(hndl, NETLINK_GENERIC)) )
goto init_return;
nl_set_buffer_size(hndl, 15000000, 15000000);
if ( (ret_val=prepare_request_message(hndl, CTRL_CMD_GETFAMILY, GENL_ID_CTRL, &msg) ) != 0 ) {
goto init_return;
}
ret_val = nla_put_string(msg,
CTRL_ATTR_FAMILY_NAME,
"DIRECTORCHNL");
if (ret_val != 0)
goto init_return;
if ( (ret_val = send_request_message(hndl, msg, 0) ) != 0 )
goto init_return;
if ( (ret_val = read_message(hndl, &ans_msg) ) != 0 )
goto init_return;
genl_hdr = nl_msg_genlhdr(ans_msg);
if (genl_hdr == NULL || genl_hdr->cmd != CTRL_CMD_NEWFAMILY) {
ret_val = -EBADMSG;
goto init_return;
}
nla = nlmsg_find_attr(nlmsg_hdr(ans_msg), sizeof(struct genlmsghdr), CTRL_ATTR_FAMILY_ID);
if (nla == NULL) {
ret_val = -EBADMSG;
goto init_return;
}
state.gnl_fid = nla_get_u16(nla);
if (state.gnl_fid == 0) {
ret_val = -EBADMSG;
goto init_return;
}
state.handle = hndl;
return 0;
init_return:
nlmsg_free(ans_msg);
if ( state.handle == NULL ) {
nl_close(hndl);
nl_handle_destroy(hndl);
}
return -EINVAL;
}
