path: root/net/l2tp/l2tp_netlink.c

// SPDX-License-Identifier: GPL-2.0-only
/* L2TP netlink layer, for management
 *
 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
 *
 * Partly based on the IrDA nelink implementation
 * (see net/irda/irnetlink.c) which is:
 * Copyright (c) 2007 Samuel Ortiz <samuel@sortiz.org>
 * which is in turn partly based on the wireless netlink code:
 * Copyright 2006 Johannes Berg <johannes@sipsolutions.net>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <net/sock.h>
#include <net/genetlink.h>
#include <net/udp.h>
#include <linux/in.h>
#include <linux/udp.h>
#include <linux/socket.h>
#include <linux/module.h>
#include <linux/list.h>
#include <net/net_namespace.h>

#include <linux/l2tp.h>

#include "l2tp_core.h"

static struct genl_family l2tp_nl_family;

static const struct genl_multicast_group l2tp_multicast_group[] = {
	{
		.name = L2TP_GENL_MCGROUP,
	},
};

static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 portid, u32 seq,
			       int flags, struct l2tp_tunnel *tunnel, u8 cmd);
static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq,
				int flags, struct l2tp_session *session,
				u8 cmd);

/* Accessed under genl lock */
static const struct l2tp_nl_cmd_ops *l2tp_nl_cmd_ops[__L2TP_PWTYPE_MAX];

static struct l2tp_session *l2tp_nl_session_get(struct genl_info *info)
{
	u32 tunnel_id;
	u32 session_id;
	char *ifname;
	struct l2tp_tunnel *tunnel;
	struct l2tp_session *session = NULL;
	struct net *net = genl_info_net(info);

	if (info->attrs[L2TP_ATTR_IFNAME]) {
		ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
		session = l2tp_session_get_by_ifname(net, ifname);
	} else if ((info->attrs[L2TP_ATTR_SESSION_ID]) &&
		   (info->attrs[L2TP_ATTR_CONN_ID])) {
		tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
		session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
		tunnel = l2tp_tunnel_get(net, tunnel_id);
		if (tunnel) {
			session = l2tp_tunnel_get_session(tunnel, session_id);
			l2tp_tunnel_dec_refcount(tunnel);
		}
	}

	return session;
}

static int l2tp_nl_cmd_noop(struct sk_buff *skb, struct genl_info *info)
{
	struct sk_buff *msg;
	void *hdr;
	int ret = -ENOBUFS;

	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
	if (!msg) {
		ret = -ENOMEM;
		goto out;
	}

	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
			  &l2tp_nl_family, 0, L2TP_CMD_NOOP);
	if (!hdr) {
		ret = -EMSGSIZE;
		goto err_out;
	}

	genlmsg_end(msg, hdr);

	return genlmsg_unicast(genl_info_net(info), msg, info->snd_portid);

err_out:
	nlmsg_free(msg);

out:
	return ret;
}

static int l2tp_tunnel_notify(struct genl_family *family,
			      struct genl_info *info,
			      struct l2tp_tunnel *tunnel,
			      u8 cmd)
{
	struct sk_buff *msg;
	int ret;

	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
	if (!msg)
		return -ENOMEM;

	ret = l2tp_nl_tunnel_send(msg, info->snd_portid, info->snd_seq,
				  NLM_F_ACK, tunnel, cmd);

	if (ret >= 0) {
		ret = genlmsg_multicast_allns(family, msg, 0, 0, GFP_ATOMIC);
		/* We don't care if no one is listening */
		if (ret == -ESRCH)
			ret = 0;
		return ret;
	}

	nlmsg_free(msg);

	return ret;
}

static int l2tp_session_notify(struct genl_family *family,
			       struct genl_info *info,
			       struct l2tp_session *session,
			       u8 cmd)
{
	struct sk_buff *msg;
	int ret;

	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
	if (!msg)
		return -ENOMEM;

	ret = l2tp_nl_session_send(msg, info->snd_portid, info->snd_seq,
				   NLM_F_ACK, session, cmd);

	if (ret >= 0) {
		ret = genlmsg_multicast_allns(family, msg, 0, 0, GFP_ATOMIC);
		/* We don't care if no one is listening */
		if (ret == -ESRCH)
			ret = 0;
		return ret;
	}

	nlmsg_free(msg);

	return ret;
}

static int l2tp_nl_cmd_tunnel_create_get_addr(struct nlattr **attrs, struct l2tp_tunnel_cfg *cfg)
{
	if (attrs[L2TP_ATTR_UDP_SPORT])
		cfg->local_udp_port = nla_get_u16(attrs[L2TP_ATTR_UDP_SPORT]);
	if (attrs[L2TP_ATTR_UDP_DPORT])
		cfg->peer_udp_port = nla_get_u16(attrs[L2TP_ATTR_UDP_DPORT]);
	cfg->use_udp_checksums = nla_get_flag(attrs[L2TP_ATTR_UDP_CSUM]);

	/* Must have either AF_INET or AF_INET6 address for source and destination */
#if IS_ENABLED(CONFIG_IPV6)
	if (attrs[L2TP_ATTR_IP6_SADDR] && attrs[L2TP_ATTR_IP6_DADDR]) {
		cfg->local_ip6 = nla_data(attrs[L2TP_ATTR_IP6_SADDR]);
		cfg->peer_ip6 = nla_data(attrs[L2TP_ATTR_IP6_DADDR]);
		cfg->udp6_zero_tx_checksums = nla_get_flag(attrs[L2TP_ATTR_UDP_ZERO_CSUM6_TX]);
		cfg->udp6_zero_rx_checksums = nla_get_flag(attrs[L2TP_ATTR_UDP_ZERO_CSUM6_RX]);
		return 0