// SPDX-License-Identifier: GPL-2.0-or-later

  /*

   * inet_diag.c	Module for monitoring INET transport protocols sockets.

   *

   * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>

   */

  #include <linux/kernel.h>

  #include <linux/module.h>
  #include <linux/types.h>
  #include <linux/fcntl.h>
  #include <linux/random.h>

  #include <linux/slab.h>

  #include <linux/cache.h>
  #include <linux/init.h>
  #include <linux/time.h>
  
  #include <net/icmp.h>
  #include <net/tcp.h>
  #include <net/ipv6.h>
  #include <net/inet_common.h>

  #include <net/inet_connection_sock.h>
  #include <net/inet_hashtables.h>
  #include <net/inet_timewait_sock.h>
  #include <net/inet6_hashtables.h>

  #include <net/bpf_sk_storage.h>

  #include <net/netlink.h>

  
  #include <linux/inet.h>
  #include <linux/stddef.h>

  #include <linux/inet_diag.h>

  #include <linux/sock_diag.h>

  static const struct inet_diag_handler **inet_diag_table;

  struct inet_diag_entry {

  	const __be32 *saddr;
  	const __be32 *daddr;

  	u16 sport;
  	u16 dport;
  	u16 family;
  	u16 userlocks;

  	u32 ifindex;

  	u32 mark;

  #ifdef CONFIG_SOCK_CGROUP_DATA
  	u64 cgroup_id;
  #endif

  };

  static DEFINE_MUTEX(inet_diag_table_mutex);

  static const struct inet_diag_handler *inet_diag_lock_handler(int proto)

  {

  	if (proto < 0 || proto >= IPPROTO_MAX) {
  		mutex_lock(&inet_diag_table_mutex);
  		return ERR_PTR(-ENOENT);
  	}

  	if (!inet_diag_table[proto])

  		sock_load_diag_module(AF_INET, proto);

  
  	mutex_lock(&inet_diag_table_mutex);

  	if (!inet_diag_table[proto])

  		return ERR_PTR(-ENOENT);

  	return inet_diag_table[proto];

  }

  static void inet_diag_unlock_handler(const struct inet_diag_handler *handler)

  {
  	mutex_unlock(&inet_diag_table_mutex);
  }

  void inet_diag_msg_common_fill(struct inet_diag_msg *r, struct sock *sk)

  {
  	r->idiag_family = sk->sk_family;
  
  	r->id.idiag_sport = htons(sk->sk_num);
  	r->id.idiag_dport = sk->sk_dport;
  	r->id.idiag_if = sk->sk_bound_dev_if;
  	sock_diag_save_cookie(sk, r->id.idiag_cookie);
  
  #if IS_ENABLED(CONFIG_IPV6)
  	if (sk->sk_family == AF_INET6) {
  		*(struct in6_addr *)r->id.idiag_src = sk->sk_v6_rcv_saddr;
  		*(struct in6_addr *)r->id.idiag_dst = sk->sk_v6_daddr;
  	} else
  #endif
  	{
  	memset(&r->id.idiag_src, 0, sizeof(r->id.idiag_src));
  	memset(&r->id.idiag_dst, 0, sizeof(r->id.idiag_dst));
  
  	r->id.idiag_src[0] = sk->sk_rcv_saddr;
  	r->id.idiag_dst[0] = sk->sk_daddr;
  	}
  }

  EXPORT_SYMBOL_GPL(inet_diag_msg_common_fill);

  static size_t inet_sk_attr_size(struct sock *sk,
  				const struct inet_diag_req_v2 *req,
  				bool net_admin)

  {

  	const struct inet_diag_handler *handler;
  	size_t aux = 0;
  
  	handler = inet_diag_table[req->sdiag_protocol];
  	if (handler && handler->idiag_get_aux_size)
  		aux = handler->idiag_get_aux_size(sk, net_admin);

  	return	  nla_total_size(sizeof(struct tcp_info))

  		+ nla_total_size(sizeof(struct inet_diag_msg))

  		+ inet_diag_msg_attrs_size()
  		+ nla_total_size(sizeof(struct inet_diag_meminfo))

  		+ nla_total_size(SK_MEMINFO_VARS * sizeof(u32))
  		+ nla_total_size(TCP_CA_NAME_MAX)
  		+ nla_total_size(sizeof(struct tcpvegas_info))

  		+ aux

  		+ 64;
  }

  int inet_diag_msg_attrs_fill(struct sock *sk, struct sk_buff *skb,
  			     struct inet_diag_msg *r, int ext,

  			     struct user_namespace *user_ns,
  			     bool net_admin)

  {
  	const struct inet_sock *inet = inet_sk(sk);

  	struct inet_diag_sockopt inet_sockopt;

  
  	if (nla_put_u8(skb, INET_DIAG_SHUTDOWN, sk->sk_shutdown))
  		goto errout;
  
  	/* IPv6 dual-stack sockets use inet->tos for IPv4 connections,
  	 * hence this needs to be included regardless of socket family.
  	 */
  	if (ext & (1 << (INET_DIAG_TOS - 1)))
  		if (nla_put_u8(skb, INET_DIAG_TOS, inet->tos) < 0)
  			goto errout;
  
  #if IS_ENABLED(CONFIG_IPV6)
  	if (r->idiag_family == AF_INET6) {
  		if (ext & (1 << (INET_DIAG_TCLASS - 1)))
  			if (nla_put_u8(skb, INET_DIAG_TCLASS,
  				       inet6_sk(sk)->tclass) < 0)
  				goto errout;
  
  		if (((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) &&
  		    nla_put_u8(skb, INET_DIAG_SKV6ONLY, ipv6_only_sock(sk)))
  			goto errout;
  	}
  #endif

  	if (net_admin && nla_put_u32(skb, INET_DIAG_MARK, sk->sk_mark))
  		goto errout;

  	if (ext & (1 << (INET_DIAG_CLASS_ID - 1)) ||
  	    ext & (1 << (INET_DIAG_TCLASS - 1))) {
  		u32 classid = 0;
  
  #ifdef CONFIG_SOCK_CGROUP_DATA
  		classid = sock_cgroup_classid(&sk->sk_cgrp_data);
  #endif
  		/* Fallback to socket priority if class id isn't set.
  		 * Classful qdiscs use it as direct reference to class.
  		 * For cgroup2 classid is always zero.
  		 */
  		if (!classid)
  			classid = sk->sk_priority;
  
  		if (nla_put_u32(skb, INET_DIAG_CLASS_ID, classid))
  			goto errout;
  	}

  #ifdef CONFIG_SOCK_CGROUP_DATA
  	if (nla_put_u64_64bit(skb, INET_DIAG_CGROUP_ID,
  			      cgroup_id(sock_cgroup_ptr(&sk->sk_cgrp_data)),
  			      INET_DIAG_PAD))
  		goto errout;
  #endif

  	r->idiag_uid = from_kuid_munged(user_ns, sock_i_uid(sk));
  	r->idiag_inode = sock_i_ino(sk);

  	memset(&inet_sockopt, 0, sizeof(inet_sockopt));
  	inet_sockopt.recverr	= inet->recverr;
  	inet_sockopt.is_icsk	= inet->is_icsk;
  	inet_sockopt.freebind	= inet->freebind;
  	inet_sockopt.hdrincl	= inet->hdrincl;
  	inet_sockopt.mc_loop	= inet->mc_loop;
  	inet_sockopt.transparent = inet->transparent;
  	inet_sockopt.mc_all	= inet->mc_all;
  	inet_sockopt.nodefrag	= inet->nodefrag;
  	inet_sockopt.bind_address_no_port = inet->bind_address_no_port;
  	inet_sockopt.recverr_rfc4884 = inet->recverr_rfc4884;
  	inet_sockopt.defer_connect = inet->defer_connect;
  	if (nla_put(skb, INET_DIAG_SOCKOPT, sizeof(inet_sockopt),
  		    &inet_sockopt))
  		goto errout;

  	return 0;
  errout:
  	return 1;
  }
  EXPORT_SYMBOL_GPL(inet_diag_msg_attrs_fill);

  static int inet_diag_parse_attrs(const struct nlmsghdr *nlh, int hdrlen,
  				 struct nlattr **req_nlas)

  {
  	struct nlattr *nla;
  	int remaining;
  
  	nlmsg_for_each_attr(nla, nlh, hdrlen, remaining) {
  		int type = nla_type(nla);

  		if (type == INET_DIAG_REQ_PROTOCOL && nla_len(nla) != sizeof(u32))
  			return -EINVAL;

  		if (type < __INET_DIAG_REQ_MAX)
  			req_nlas[type] = nla;
  	}

  	return 0;

  }
  
  static int inet_diag_get_protocol(const struct inet_diag_req_v2 *req,
  				  const struct inet_diag_dump_data *data)
  {
  	if (data->req_nlas[INET_DIAG_REQ_PROTOCOL])
  		return nla_get_u32(data->req_nlas[INET_DIAG_REQ_PROTOCOL]);
  	return req->sdiag_protocol;
  }

  #define MAX_DUMP_ALLOC_SIZE (KMALLOC_MAX_SIZE - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))

  int inet_sk_diag_fill(struct sock *sk, struct inet_connection_sock *icsk,

  		      struct sk_buff *skb, struct netlink_callback *cb,
  		      const struct inet_diag_req_v2 *req,
  		      u16 nlmsg_flags, bool net_admin)

  {

  	const struct tcp_congestion_ops *ca_ops;

  	const struct inet_diag_handler *handler;

  	struct inet_diag_dump_data *cb_data;

  	int ext = req->idiag_ext;

  	struct inet_diag_msg *r;

  	struct nlmsghdr  *nlh;

  	struct nlattr *attr;

  	void *info = NULL;

  	cb_data = cb->data;

  	handler = inet_diag_table[inet_diag_get_protocol(req, cb_data)];

  	BUG_ON(!handler);

  	nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
  			cb->nlh->nlmsg_type, sizeof(*r), nlmsg_flags);

  	if (!nlh)

  		return -EMSGSIZE;

  	r = nlmsg_data(nlh);

  	BUG_ON(!sk_fullsock(sk));

  	inet_diag_msg_common_fill(r, sk);

  	r->idiag_state = sk->sk_state;
  	r->idiag_timer = 0;
  	r->idiag_retrans = 0;

  	if (inet_diag_msg_attrs_fill(sk, skb, r, ext,
  				     sk_user_ns(NETLINK_CB(cb->skb).sk),
  				     net_admin))

  		goto errout;

  	if (ext & (1 << (INET_DIAG_MEMINFO - 1))) {
  		struct inet_diag_meminfo minfo = {
  			.idiag_rmem = sk_rmem_alloc_get(sk),

  			.idiag_wmem = READ_ONCE(sk->sk_wmem_queued),

  			.idiag_fmem = sk->sk_forward_alloc,
  			.idiag_tmem = sk_wmem_alloc_get(sk),
  		};
  
  		if (nla_put(skb, INET_DIAG_MEMINFO, sizeof(minfo), &minfo) < 0)
  			goto errout;

  	}

  	if (ext & (1 << (INET_DIAG_SKMEMINFO - 1)))
  		if (sock_diag_put_meminfo(sk, skb, INET_DIAG_SKMEMINFO))

  			goto errout;

  	/*
  	 * RAW sockets might have user-defined protocols assigned,
  	 * so report the one supplied on socket creation.
  	 */
  	if (sk->sk_type == SOCK_RAW) {
  		if (nla_put_u8(skb, INET_DIAG_PROTOCOL, sk->sk_protocol))
  			goto errout;
  	}

  	if (!icsk) {

  		handler->idiag_get_info(sk, r, NULL);

  		goto out;
  	}

  	if (icsk->icsk_pending == ICSK_TIME_RETRANS ||

  	    icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||

  	    icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {

  		r->idiag_timer = 1;
  		r->idiag_retrans = icsk->icsk_retransmits;

  		r->idiag_expires =

  			jiffies_delta_to_msecs(icsk->icsk_timeout - jiffies);

  	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {

  		r->idiag_timer = 4;
  		r->idiag_retrans = icsk->icsk_probes_out;

  		r->idiag_expires =

  			jiffies_delta_to_msecs(icsk->icsk_timeout - jiffies);

  	} else if (timer_pending(&sk->sk_timer)) {

  		r->idiag_timer = 2;
  		r->idiag_retrans = icsk->icsk_probes_out;

  		r->idiag_expires =

  			jiffies_delta_to_msecs(sk->sk_timer.expires - jiffies);

  	} else {

  		r->idiag_timer = 0;
  		r->idiag_expires = 0;

  	}

  	if ((ext & (1 << (INET_DIAG_INFO - 1))) && handler->idiag_info_size) {

  		attr = nla_reserve_64bit(skb, INET_DIAG_INFO,
  					 handler->idiag_info_size,
  					 INET_DIAG_PAD);

  		if (!attr)
  			goto errout;

  		info = nla_data(attr);

  	}

  	if (ext & (1 << (INET_DIAG_CONG - 1))) {
  		int err = 0;
  
  		rcu_read_lock();
  		ca_ops = READ_ONCE(icsk->icsk_ca_ops);
  		if (ca_ops)
  			err = nla_put_string(skb, INET_DIAG_CONG, ca_ops->name);
  		rcu_read_unlock();
  		if (err < 0)

  			goto errout;

  	}

  	handler->idiag_get_info(sk, r, info);

  	if (ext & (1 << (INET_DIAG_INFO - 1)) && handler->idiag_get_aux)
  		if (handler->idiag_get_aux(sk, net_admin, skb) < 0)
  			goto errout;

  	if (sk->sk_state < TCP_TIME_WAIT) {

  		union tcp_cc_info info;
  		size_t sz = 0;
  		int attr;

  
  		rcu_read_lock();
  		ca_ops = READ_ONCE(icsk->icsk_ca_ops);
  		if (ca_ops && ca_ops->get_info)

  			sz = ca_ops->get_info(sk, ext, &attr, &info);

  		rcu_read_unlock();

  		if (sz && nla_put(skb, attr, sz, &info) < 0)

  			goto errout;
  	}

  	/* Keep it at the end for potential retry with a larger skb,
  	 * or else do best-effort fitting, which is only done for the
  	 * first_nlmsg.
  	 */
  	if (cb_data->bpf_stg_diag) {
  		bool first_nlmsg = ((unsigned char *)nlh == skb->data);
  		unsigned int prev_min_dump_alloc;
  		unsigned int total_nla_size = 0;
  		unsigned int msg_len;
  		int err;
  
  		msg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
  		err = bpf_sk_storage_diag_put(cb_data->bpf_stg_diag, sk, skb,
  					      INET_DIAG_SK_BPF_STORAGES,
  					      &total_nla_size);
  
  		if (!err)
  			goto out;
  
  		total_nla_size += msg_len;
  		prev_min_dump_alloc = cb->min_dump_alloc;
  		if (total_nla_size > prev_min_dump_alloc)
  			cb->min_dump_alloc = min_t(u32, total_nla_size,
  						   MAX_DUMP_ALLOC_SIZE);
  
  		if (!first_nlmsg)
  			goto errout;
  
  		if (cb->min_dump_alloc > prev_min_dump_alloc)
  			/* Retry with pskb_expand_head() with
  			 * __GFP_DIRECT_RECLAIM
  			 */
  			goto errout;
  
  		WARN_ON_ONCE(total_nla_size <= prev_min_dump_alloc);
  
  		/* Send what we have for this sk
  		 * and move on to the next sk in the following
  		 * dump()
  		 */
  	}

  out:

  	nlmsg_end(skb, nlh);
  	return 0;

  errout:
  	nlmsg_cancel(skb, nlh);

  	return -EMSGSIZE;

  }

  EXPORT_SYMBOL_GPL(inet_sk_diag_fill);

  static int inet_twsk_diag_fill(struct sock *sk,

  			       struct sk_buff *skb,

  			       struct netlink_callback *cb,
  			       u16 nlmsg_flags)

  {

  	struct inet_timewait_sock *tw = inet_twsk(sk);

  	struct inet_diag_msg *r;

  	struct nlmsghdr *nlh;

  	long tmo;

  	nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid,
  			cb->nlh->nlmsg_seq, cb->nlh->nlmsg_type,
  			sizeof(*r), nlmsg_flags);

  	if (!nlh)

  		return -EMSGSIZE;

  	r = nlmsg_data(nlh);

  	BUG_ON(tw->tw_state != TCP_TIME_WAIT);

  	inet_diag_msg_common_fill(r, sk);

  	r->idiag_retrans      = 0;

  	r->idiag_state	      = tw->tw_substate;
  	r->idiag_timer	      = 3;

  	tmo = tw->tw_timer.expires - jiffies;
  	r->idiag_expires      = jiffies_delta_to_msecs(tmo);

  	r->idiag_rqueue	      = 0;
  	r->idiag_wqueue	      = 0;
  	r->idiag_uid	      = 0;
  	r->idiag_inode	      = 0;

  	nlmsg_end(skb, nlh);
  	return 0;

  }

  static int inet_req_diag_fill(struct sock *sk, struct sk_buff *skb,

  			      struct netlink_callback *cb,
  			      u16 nlmsg_flags, bool net_admin)

  {

  	struct request_sock *reqsk = inet_reqsk(sk);

  	struct inet_diag_msg *r;
  	struct nlmsghdr *nlh;
  	long tmo;

  	nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
  			cb->nlh->nlmsg_type, sizeof(*r), nlmsg_flags);

  	if (!nlh)
  		return -EMSGSIZE;
  
  	r = nlmsg_data(nlh);
  	inet_diag_msg_common_fill(r, sk);
  	r->idiag_state = TCP_SYN_RECV;
  	r->idiag_timer = 1;

  	r->idiag_retrans = reqsk->num_retrans;

  
  	BUILD_BUG_ON(offsetof(struct inet_request_sock, ir_cookie) !=
  		     offsetof(struct sock, sk_cookie));

  	tmo = inet_reqsk(sk)->rsk_timer.expires - jiffies;

  	r->idiag_expires = jiffies_delta_to_msecs(tmo);

  	r->idiag_rqueue	= 0;
  	r->idiag_wqueue	= 0;
  	r->idiag_uid	= 0;
  	r->idiag_inode	= 0;

  	if (net_admin && nla_put_u32(skb, INET_DIAG_MARK,

  				     inet_rsk(reqsk)->ir_mark)) {
  		nlmsg_cancel(skb, nlh);

  		return -EMSGSIZE;

  	}

  	nlmsg_end(skb, nlh);
  	return 0;
  }

  static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,

  			struct netlink_callback *cb,

  			const struct inet_diag_req_v2 *r,

  			u16 nlmsg_flags, bool net_admin)

  {
  	if (sk->sk_state == TCP_TIME_WAIT)

  		return inet_twsk_diag_fill(sk, skb, cb, nlmsg_flags);

  	if (sk->sk_state == TCP_NEW_SYN_RECV)

  		return inet_req_diag_fill(sk, skb, cb, nlmsg_flags, net_admin);

  	return inet_sk_diag_fill(sk, inet_csk(sk), skb, cb, r, nlmsg_flags,
  				 net_admin);

  }

  struct sock *inet_diag_find_one_icsk(struct net *net,
  				     struct inet_hashinfo *hashinfo,
  				     const struct inet_diag_req_v2 *req)

  {

  	struct sock *sk;

  	rcu_read_lock();

  	if (req->sdiag_family == AF_INET)

  		sk = inet_lookup(net, hashinfo, NULL, 0, req->id.idiag_dst[0],

  				 req->id.idiag_dport, req->id.idiag_src[0],
  				 req->id.idiag_sport, req->id.idiag_if);

  #if IS_ENABLED(CONFIG_IPV6)

  	else if (req->sdiag_family == AF_INET6) {
  		if (ipv6_addr_v4mapped((struct in6_addr *)req->id.idiag_dst) &&
  		    ipv6_addr_v4mapped((struct in6_addr *)req->id.idiag_src))

  			sk = inet_lookup(net, hashinfo, NULL, 0, req->id.idiag_dst[3],

  					 req->id.idiag_dport, req->id.idiag_src[3],
  					 req->id.idiag_sport, req->id.idiag_if);
  		else

  			sk = inet6_lookup(net, hashinfo, NULL, 0,

  					  (struct in6_addr *)req->id.idiag_dst,
  					  req->id.idiag_dport,
  					  (struct in6_addr *)req->id.idiag_src,
  					  req->id.idiag_sport,
  					  req->id.idiag_if);
  	}

  #endif

  	else {
  		rcu_read_unlock();

  		return ERR_PTR(-EINVAL);

  	}
  	rcu_read_unlock();

  	if (!sk)

  		return ERR_PTR(-ENOENT);

  	if (sock_diag_check_cookie(sk, req->id.idiag_cookie)) {
  		sock_gen_put(sk);
  		return ERR_PTR(-ENOENT);
  	}
  
  	return sk;
  }
  EXPORT_SYMBOL_GPL(inet_diag_find_one_icsk);
  
  int inet_diag_dump_one_icsk(struct inet_hashinfo *hashinfo,

  			    struct netlink_callback *cb,

  			    const struct inet_diag_req_v2 *req)
  {

  	struct sk_buff *in_skb = cb->skb;

  	bool net_admin = netlink_net_capable(in_skb, CAP_NET_ADMIN);

  	struct net *net = sock_net(in_skb->sk);
  	struct sk_buff *rep;
  	struct sock *sk;
  	int err;
  
  	sk = inet_diag_find_one_icsk(net, hashinfo, req);
  	if (IS_ERR(sk))
  		return PTR_ERR(sk);

  	rep = nlmsg_new(inet_sk_attr_size(sk, req, net_admin), GFP_KERNEL);

  	if (!rep) {
  		err = -ENOMEM;

  		goto out;

  	}

  	err = sk_diag_fill(sk, rep, cb, req, 0, net_admin);

  	if (err < 0) {
  		WARN_ON(err == -EMSGSIZE);

  		nlmsg_free(rep);

  		goto out;
  	}

  	err = netlink_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid,

  			      MSG_DONTWAIT);

  	if (err > 0)
  		err = 0;
  
  out:

  	if (sk)
  		sock_gen_put(sk);

  	return err;
  }

  EXPORT_SYMBOL_GPL(inet_diag_dump_one_icsk);

  static int inet_diag_cmd_exact(int cmd, struct sk_buff *in_skb,

  			       const struct nlmsghdr *nlh,

  			       int hdrlen,

  			       const struct inet_diag_req_v2 *req)

  {
  	const struct inet_diag_handler *handler;

  	struct inet_diag_dump_data dump_data;
  	int err, protocol;
  
  	memset(&dump_data, 0, sizeof(dump_data));

  	err = inet_diag_parse_attrs(nlh, hdrlen, dump_data.req_nlas);
  	if (err)
  		return err;

  	protocol = inet_diag_get_protocol(req, &dump_data);

  	handler = inet_diag_lock_handler(protocol);

  	if (IS_ERR(handler)) {

  		err = PTR_ERR(handler);

  	} else if (cmd == SOCK_DIAG_BY_FAMILY) {
  		struct netlink_callback cb = {
  			.nlh = nlh,
  			.skb = in_skb,

  			.data = &dump_data,

  		};
  		err = handler->dump_one(&cb, req);
  	} else if (cmd == SOCK_DESTROY && handler->destroy) {

  		err = handler->destroy(in_skb, req);

  	} else {

  		err = -EOPNOTSUPP;

  	}

  	inet_diag_unlock_handler(handler);

  	return err;
  }

  static int bitstring_match(const __be32 *a1, const __be32 *a2, int bits)

  {
  	int words = bits >> 5;
  
  	bits &= 0x1f;
  
  	if (words) {
  		if (memcmp(a1, a2, words << 2))
  			return 0;
  	}
  	if (bits) {

  		__be32 w1, w2;
  		__be32 mask;

  
  		w1 = a1[words];
  		w2 = a2[words];
  
  		mask = htonl((0xffffffff) << (32 - bits));
  
  		if ((w1 ^ w2) & mask)
  			return 0;
  	}
  
  	return 1;
  }

  static int inet_diag_bc_run(const struct nlattr *_bc,

  			    const struct inet_diag_entry *entry)

  {

  	const void *bc = nla_data(_bc);
  	int len = nla_len(_bc);

  	while (len > 0) {
  		int yes = 1;

  		const struct inet_diag_bc_op *op = bc;

  
  		switch (op->code) {

  		case INET_DIAG_BC_NOP:

  			break;

  		case INET_DIAG_BC_JMP:

  			yes = 0;
  			break;

  		case INET_DIAG_BC_S_EQ:
  			yes = entry->sport == op[1].no;
  			break;

  		case INET_DIAG_BC_S_GE:

  			yes = entry->sport >= op[1].no;
  			break;

  		case INET_DIAG_BC_S_LE:

  			yes = entry->sport <= op[1].no;

  			break;

  		case INET_DIAG_BC_D_EQ:
  			yes = entry->dport == op[1].no;
  			break;

  		case INET_DIAG_BC_D_GE:

  			yes = entry->dport >= op[1].no;
  			break;

  		case INET_DIAG_BC_D_LE:

  			yes = entry->dport <= op[1].no;
  			break;

  		case INET_DIAG_BC_AUTO:

  			yes = !(entry->userlocks & SOCK_BINDPORT_LOCK);
  			break;

  		case INET_DIAG_BC_S_COND:

  		case INET_DIAG_BC_D_COND: {

  			const struct inet_diag_hostcond *cond;
  			const __be32 *addr;

  			cond = (const struct inet_diag_hostcond *)(op + 1);

  			if (cond->port != -1 &&

  			    cond->port != (op->code == INET_DIAG_BC_S_COND ?

  					     entry->sport : entry->dport)) {
  				yes = 0;
  				break;
  			}

  			if (op->code == INET_DIAG_BC_S_COND)

  				addr = entry->saddr;
  			else
  				addr = entry->daddr;

  			if (cond->family != AF_UNSPEC &&
  			    cond->family != entry->family) {
  				if (entry->family == AF_INET6 &&
  				    cond->family == AF_INET) {
  					if (addr[0] == 0 && addr[1] == 0 &&
  					    addr[2] == htonl(0xffff) &&
  					    bitstring_match(addr + 3,
  							    cond->addr,
  							    cond->prefix_len))
  						break;
  				}
  				yes = 0;
  				break;
  			}
  
  			if (cond->prefix_len == 0)
  				break;

  			if (bitstring_match(addr, cond->addr,
  					    cond->prefix_len))

  				break;

  			yes = 0;
  			break;
  		}

  		case INET_DIAG_BC_DEV_COND: {
  			u32 ifindex;
  
  			ifindex = *((const u32 *)(op + 1));
  			if (ifindex != entry->ifindex)
  				yes = 0;
  			break;
  		}

  		case INET_DIAG_BC_MARK_COND: {
  			struct inet_diag_markcond *cond;
  
  			cond = (struct inet_diag_markcond *)(op + 1);
  			if ((entry->mark & cond->mask) != cond->mark)
  				yes = 0;
  			break;
  		}

  #ifdef CONFIG_SOCK_CGROUP_DATA
  		case INET_DIAG_BC_CGROUP_COND: {
  			u64 cgroup_id;
  
  			cgroup_id = get_unaligned((const u64 *)(op + 1));
  			if (cgroup_id != entry->cgroup_id)
  				yes = 0;
  			break;
  		}
  #endif

  		}

  		if (yes) {

  			len -= op->yes;
  			bc += op->yes;
  		} else {
  			len -= op->no;
  			bc += op->no;
  		}
  	}

  	return len == 0;

  }

  /* This helper is available for all sockets (ESTABLISH, TIMEWAIT, SYN_RECV)
   */
  static void entry_fill_addrs(struct inet_diag_entry *entry,
  			     const struct sock *sk)
  {
  #if IS_ENABLED(CONFIG_IPV6)
  	if (sk->sk_family == AF_INET6) {
  		entry->saddr = sk->sk_v6_rcv_saddr.s6_addr32;
  		entry->daddr = sk->sk_v6_daddr.s6_addr32;
  	} else
  #endif
  	{
  		entry->saddr = &sk->sk_rcv_saddr;
  		entry->daddr = &sk->sk_daddr;
  	}
  }

  int inet_diag_bc_sk(const struct nlattr *bc, struct sock *sk)
  {

  	struct inet_sock *inet = inet_sk(sk);

  	struct inet_diag_entry entry;

  	if (!bc)

  		return 1;
  
  	entry.family = sk->sk_family;

  	entry_fill_addrs(&entry, sk);

  	entry.sport = inet->inet_num;
  	entry.dport = ntohs(inet->inet_dport);

  	entry.ifindex = sk->sk_bound_dev_if;

  	entry.userlocks = sk_fullsock(sk) ? sk->sk_userlocks : 0;

  	if (sk_fullsock(sk))
  		entry.mark = sk->sk_mark;
  	else if (sk->sk_state == TCP_NEW_SYN_RECV)
  		entry.mark = inet_rsk(inet_reqsk(sk))->ir_mark;
  	else
  		entry.mark = 0;

  #ifdef CONFIG_SOCK_CGROUP_DATA

  	entry.cgroup_id = sk_fullsock(sk) ?
  		cgroup_id(sock_cgroup_ptr(&sk->sk_cgrp_data)) : 0;

  #endif

  
  	return inet_diag_bc_run(bc, &entry);
  }
  EXPORT_SYMBOL_GPL(inet_diag_bc_sk);

  static int valid_cc(const void *bc, int len, int cc)
  {
  	while (len >= 0) {

  		const struct inet_diag_bc_op *op = bc;

  
  		if (cc > len)
  			return 0;
  		if (cc == len)
  			return 1;

  		if (op->yes < 4 || op->yes & 3)

  			return 0;
  		len -= op->yes;
  		bc  += op->yes;
  	}
  	return 0;
  }

  /* data is u32 ifindex */
  static bool valid_devcond(const struct inet_diag_bc_op *op, int len,
  			  int *min_len)
  {
  	/* Check ifindex space. */
  	*min_len += sizeof(u32);
  	if (len < *min_len)
  		return false;
  
  	return true;
  }

  /* Validate an inet_diag_hostcond. */
  static bool valid_hostcond(const struct inet_diag_bc_op *op, int len,
  			   int *min_len)
  {

  	struct inet_diag_hostcond *cond;

  	int addr_len;

  
  	/* Check hostcond space. */
  	*min_len += sizeof(struct inet_diag_hostcond);
  	if (len < *min_len)
  		return false;
  	cond = (struct inet_diag_hostcond *)(op + 1);
  
  	/* Check address family and address length. */
  	switch (cond->family) {
  	case AF_UNSPEC:
  		addr_len = 0;
  		break;
  	case AF_INET:
  		addr_len = sizeof(struct in_addr);
  		break;
  	case AF_INET6:
  		addr_len = sizeof(struct in6_addr);
  		break;
  	default:
  		return false;
  	}
  	*min_len += addr_len;
  	if (len < *min_len)
  		return false;
  
  	/* Check prefix length (in bits) vs address length (in bytes). */
  	if (cond->prefix_len > 8 * addr_len)
  		return false;
  
  	return true;
  }

  /* Validate a port comparison operator. */

  static bool valid_port_comparison(const struct inet_diag_bc_op *op,
  				  int len, int *min_len)

  {
  	/* Port comparisons put the port in a follow-on inet_diag_bc_op. */
  	*min_len += sizeof(struct inet_diag_bc_op);
  	if (len < *min_len)
  		return false;
  	return true;
  }

  static bool valid_markcond(const struct inet_diag_bc_op *op, int len,
  			   int *min_len)

  {

  	*min_len += sizeof(struct inet_diag_markcond);
  	return len >= *min_len;
  }

  #ifdef CONFIG_SOCK_CGROUP_DATA
  static bool valid_cgroupcond(const struct inet_diag_bc_op *op, int len,
  			     int *min_len)
  {
  	*min_len += sizeof(u64);
  	return len >= *min_len;
  }
  #endif

  static int inet_diag_bc_audit(const struct nlattr *attr,
  			      const struct sk_buff *skb)
  {
  	bool net_admin = netlink_net_capable(skb, CAP_NET_ADMIN);

  	const void *bytecode, *bc;
  	int bytecode_len, len;
  
  	if (!attr || nla_len(attr) < sizeof(struct inet_diag_bc_op))
  		return -EINVAL;
  
  	bytecode = bc = nla_data(attr);
  	len = bytecode_len = nla_len(attr);

  
  	while (len > 0) {

  		int min_len = sizeof(struct inet_diag_bc_op);

  		const struct inet_diag_bc_op *op = bc;

  		switch (op->code) {

  		case INET_DIAG_BC_S_COND:
  		case INET_DIAG_BC_D_COND:

  			if (!valid_hostcond(bc, len, &min_len))
  				return -EINVAL;

  			break;

  		case INET_DIAG_BC_DEV_COND:
  			if (!valid_devcond(bc, len, &min_len))
  				return -EINVAL;
  			break;

  		case INET_DIAG_BC_S_EQ:

  		case INET_DIAG_BC_S_GE:
  		case INET_DIAG_BC_S_LE:

  		case INET_DIAG_BC_D_EQ:

  		case INET_DIAG_BC_D_GE:
  		case INET_DIAG_BC_D_LE:

  			if (!valid_port_comparison(bc, len, &min_len))

  				return -EINVAL;
  			break;

  		case INET_DIAG_BC_MARK_COND:
  			if (!net_admin)
  				return -EPERM;
  			if (!valid_markcond(bc, len, &min_len))
  				return -EINVAL;
  			break;

  #ifdef CONFIG_SOCK_CGROUP_DATA
  		case INET_DIAG_BC_CGROUP_COND:
  			if (!valid_cgroupcond(bc, len, &min_len))
  				return -EINVAL;
  			break;
  #endif

  		case INET_DIAG_BC_AUTO:
  		case INET_DIAG_BC_JMP:

  		case INET_DIAG_BC_NOP:

  			break;
  		default:
  			return -EINVAL;
  		}

  
  		if (op->code != INET_DIAG_BC_NOP) {
  			if (op->no < min_len || op->no > len + 4 || op->no & 3)
  				return -EINVAL;
  			if (op->no < len &&
  			    !valid_cc(bytecode, bytecode_len, len - op->no))
  				return -EINVAL;
  		}

  		if (op->yes < min_len || op->yes > len + 4 || op->yes & 3)

  			return -EINVAL;

  		bc  += op->yes;

  		len -= op->yes;
  	}
  	return len == 0 ? 0 : -EINVAL;
  }

  static void twsk_build_assert(void)
  {
  	BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_family) !=
  		     offsetof(struct sock, sk_family));
  
  	BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_num) !=
  		     offsetof(struct inet_sock, inet_num));
  
  	BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_dport) !=
  		     offsetof(struct inet_sock, inet_dport));
  
  	BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_rcv_saddr) !=
  		     offsetof(struct inet_sock, inet_rcv_saddr));
  
  	BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_daddr) !=
  		     offsetof(struct inet_sock, inet_daddr));
  
  #if IS_ENABLED(CONFIG_IPV6)
  	BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_v6_rcv_saddr) !=
  		     offsetof(struct sock, sk_v6_rcv_saddr));
  
  	BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_v6_daddr) !=
  		     offsetof(struct sock, sk_v6_daddr));
  #endif
  }

  void inet_diag_dump_icsk(struct inet_hashinfo *hashinfo, struct sk_buff *skb,

  			 struct netlink_callback *cb,

  			 const struct inet_diag_req_v2 *r)

  {

  	bool net_admin = netlink_net_capable(cb->skb, CAP_NET_ADMIN);

  	struct inet_diag_dump_data *cb_data = cb->data;

  	struct net *net = sock_net(skb->sk);

  	u32 idiag_states = r->idiag_states;

  	int i, num, s_i, s_num;

  	struct nlattr *bc;

  	struct sock *sk;

  	bc = cb_data->inet_diag_nla_bc;

  	if (idiag_states & TCPF_SYN_RECV)
  		idiag_states |= TCPF_NEW_SYN_RECV;

  	s_i = cb->args[1];
  	s_num = num = cb->args[2];

  	if (cb->args[0] == 0) {

  		if (!(idiag_states & TCPF_LISTEN) || r->id.idiag_dport)

  			goto skip_listen_ht;

  		for (i = s_i; i < INET_LHTABLE_SIZE; i++) {

  			struct inet_listen_hashbucket *ilb;

  			struct hlist_nulls_node *node;

  
  			num = 0;

  			ilb = &hashinfo->listening_hash[i];

  			spin_lock(&ilb->lock);

  			sk_nulls_for_each(sk, node, &ilb->nulls_head) {

  				struct inet_sock *inet = inet_sk(sk);

  				if (!net_eq(sock_net(sk), net))
  					continue;

  				if (num < s_num) {
  					num++;
  					continue;
  				}

  				if (r->sdiag_family != AF_UNSPEC &&

  				    sk->sk_family != r->sdiag_family)

  					goto next_listen;

  				if (r->id.idiag_sport != inet->inet_sport &&

  				    r->id.idiag_sport)

  					goto next_listen;

  				if (!inet_diag_bc_sk(bc, sk))
  					goto next_listen;
  
  				if (inet_sk_diag_fill(sk, inet_csk(sk), skb,
  						      cb, r, NLM_F_MULTI,
  						      net_admin) < 0) {

  					spin_unlock(&ilb->lock);

  					goto done;
  				}
  
  next_listen:

  				++num;
  			}

  			spin_unlock(&ilb->lock);

  
  			s_num = 0;

  		}

  skip_listen_ht:
  		cb->args[0] = 1;
  		s_i = num = s_num = 0;
  	}

  	if (!(idiag_states & ~TCPF_LISTEN))

  		goto out;

  #define SKARR_SZ 16

  	for (i = s_i; i <= hashinfo->ehash_mask; i++) {

  		struct inet_ehash_bucket *head = &hashinfo->ehash[i];

  		spinlock_t *lock = inet_ehash_lockp(hashinfo, i);

  		struct hlist_nulls_node *node;

  		struct sock *sk_arr[SKARR_SZ];
  		int num_arr[SKARR_SZ];
  		int idx, accum, res;

  		if (hlist_nulls_empty(&head->chain))

  			continue;

  		if (i > s_i)
  			s_num = 0;

  next_chunk:
  		num = 0;
  		accum = 0;

  		spin_lock_bh(lock);

  		sk_nulls_for_each(sk, node, &head->chain) {

  			int state;

  			if (!net_eq(sock_net(sk), net))
  				continue;

  			if (num < s_num)
  				goto next_normal;

  			state = (sk->sk_state == TCP_TIME_WAIT) ?
  				inet_twsk(sk)->tw_substate : sk->sk_state;

  			if (!(idiag_states & (1 << state)))

  				goto next_normal;

  			if (r->sdiag_family != AF_UNSPEC &&

  			    sk->sk_family != r->sdiag_family)

  				goto next_normal;

  			if (r->id.idiag_sport != htons(sk->sk_num) &&

  			    r->id.idiag_sport)

  				goto next_normal;

  			if (r->id.idiag_dport != sk->sk_dport &&

  			    r->id.idiag_dport)

  				goto next_normal;

  			twsk_build_assert();
  
  			if (!inet_diag_bc_sk(bc, sk))
  				goto next_normal;

  			if (!refcount_inc_not_zero(&sk->sk_refcnt))
  				goto next_normal;

  			num_arr[accum] = num;
  			sk_arr[accum] = sk;
  			if (++accum == SKARR_SZ)
  				break;
  next_normal:
  			++num;
  		}
  		spin_unlock_bh(lock);
  		res = 0;
  		for (idx = 0; idx < accum; idx++) {
  			if (res >= 0) {

  				res = sk_diag_fill(sk_arr[idx], skb, cb, r,
  						   NLM_F_MULTI, net_admin);

  				if (res < 0)
  					num = num_arr[idx];

  			}

  			sock_gen_put(sk_arr[idx]);

  		}

  		if (res < 0)
  			break;

  		cond_resched();

  		if (accum == SKARR_SZ) {
  			s_num = num + 1;
  			goto next_chunk;
  		}

  	}
  
  done:
  	cb->args[1] = i;
  	cb->args[2] = num;

  out:
  	;
  }

  EXPORT_SYMBOL_GPL(inet_diag_dump_icsk);

  
  static int __inet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,

  			    const struct inet_diag_req_v2 *r)

  {

  	struct inet_diag_dump_data *cb_data = cb->data;

  	const struct inet_diag_handler *handler;

  	u32 prev_min_dump_alloc;

  	int protocol, err = 0;
  
  	protocol = inet_diag_get_protocol(r, cb_data);

  again:
  	prev_min_dump_alloc = cb->min_dump_alloc;

  	handler = inet_diag_lock_handler(protocol);

  	if (!IS_ERR(handler))

  		handler->dump(skb, cb, r);

  	else
  		err = PTR_ERR(handler);

  	inet_diag_unlock_handler(handler);

  	/* The skb is not large enough to fit one sk info and
  	 * inet_sk_diag_fill() has requested for a larger skb.
  	 */
  	if (!skb->len && cb->min_dump_alloc > prev_min_dump_alloc) {
  		err = pskb_expand_head(skb, 0, cb->min_dump_alloc, GFP_KERNEL);
  		if (!err)
  			goto again;
  	}

  	return err ? : skb->len;

  }

  static int inet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
  {

  	return __inet_diag_dump(skb, cb, nlmsg_data(cb->nlh));
  }
  
  static int __inet_diag_dump_start(struct netlink_callback *cb, int hdrlen)
  {
  	const struct nlmsghdr *nlh = cb->nlh;
  	struct inet_diag_dump_data *cb_data;
  	struct sk_buff *skb = cb->skb;
  	struct nlattr *nla;

  	int err;

  
  	cb_data = kzalloc(sizeof(*cb_data), GFP_KERNEL);
  	if (!cb_data)
  		return -ENOMEM;

  	err = inet_diag_parse_attrs(nlh, hdrlen, cb_data->req_nlas);
  	if (err) {
  		kfree(cb_data);
  		return err;
  	}

  	nla = cb_data->inet_diag_nla_bc;
  	if (nla) {
  		err = inet_diag_bc_audit(nla, skb);
  		if (err) {
  			kfree(cb_data);
  			return err;
  		}
  	}

  	nla = cb_data->inet_diag_nla_bpf_stgs;
  	if (nla) {
  		struct bpf_sk_storage_diag *bpf_stg_diag;
  
  		bpf_stg_diag = bpf_sk_storage_diag_alloc(nla);
  		if (IS_ERR(bpf_stg_diag)) {
  			kfree(cb_data);
  			return PTR_ERR(bpf_stg_diag);
  		}
  		cb_data->bpf_stg_diag = bpf_stg_diag;
  	}

  	cb->data = cb_data;
  	return 0;
  }

  static int inet_diag_dump_start(struct netlink_callback *cb)
  {
  	return __inet_diag_dump_start(cb, sizeof(struct inet_diag_req_v2));
  }
  
  static int inet_diag_dump_start_compat(struct netlink_callback *cb)
  {
  	return __inet_diag_dump_start(cb, sizeof(struct inet_diag_req));
  }
  
  static int inet_diag_dump_done(struct netlink_callback *cb)
  {

  	struct inet_diag_dump_data *cb_data = cb->data;
  
  	bpf_sk_storage_diag_free(cb_data->bpf_stg_diag);

  	kfree(cb->data);
  
  	return 0;

  }

  static int inet_diag_type2proto(int type)

  {
  	switch (type) {
  	case TCPDIAG_GETSOCK:
  		return IPPROTO_TCP;
  	case DCCPDIAG_GETSOCK:
  		return IPPROTO_DCCP;
  	default:
  		return 0;
  	}
  }

  static int inet_diag_dump_compat(struct sk_buff *skb,
  				 struct netlink_callback *cb)

  {

  	struct inet_diag_req *rc = nlmsg_data(cb->nlh);

  	struct inet_diag_req_v2 req;

  	req.sdiag_family = AF_UNSPEC; /* compatibility */

  	req.sdiag_protocol = inet_diag_type2proto(cb->nlh->nlmsg_type);
  	req.idiag_ext = rc->idiag_ext;
  	req.idiag_states = rc->idiag_states;
  	req.id = rc->id;

  	return __inet_diag_dump(skb, cb, &req);

  }

  static int inet_diag_get_exact_compat(struct sk_buff *in_skb,

  				      const struct nlmsghdr *nlh)

  {

  	struct inet_diag_req *rc = nlmsg_data(nlh);

  	struct inet_diag_req_v2 req;

  
  	req.sdiag_family = rc->idiag_family;
  	req.sdiag_protocol = inet_diag_type2proto(nlh->nlmsg_type);
  	req.idiag_ext = rc->idiag_ext;
  	req.idiag_states = rc->idiag_states;
  	req.id = rc->id;

  	return inet_diag_cmd_exact(SOCK_DIAG_BY_FAMILY, in_skb, nlh,
  				   sizeof(struct inet_diag_req), &req);

  }

  static int inet_diag_rcv_msg_compat(struct sk_buff *skb, struct nlmsghdr *nlh)

  {

  	int hdrlen = sizeof(struct inet_diag_req);

  	struct net *net = sock_net(skb->sk);

  	if (nlh->nlmsg_type >= INET_DIAG_GETSOCK_MAX ||
  	    nlmsg_len(nlh) < hdrlen)
  		return -EINVAL;

  	if (nlh->nlmsg_flags & NLM_F_DUMP) {

  		struct netlink_dump_control c = {
  			.start = inet_diag_dump_start_compat,
  			.done = inet_diag_dump_done,
  			.dump = inet_diag_dump_compat,
  		};
  		return netlink_dump_start(net->diag_nlsk, skb, nlh, &c);

  	}

  	return inet_diag_get_exact_compat(skb, nlh);

  }

  static int inet_diag_handler_cmd(struct sk_buff *skb, struct nlmsghdr *h)

  {

  	int hdrlen = sizeof(struct inet_diag_req_v2);

  	struct net *net = sock_net(skb->sk);

  
  	if (nlmsg_len(h) < hdrlen)
  		return -EINVAL;

  	if (h->nlmsg_type == SOCK_DIAG_BY_FAMILY &&
  	    h->nlmsg_flags & NLM_F_DUMP) {

  		struct netlink_dump_control c = {
  			.start = inet_diag_dump_start,
  			.done = inet_diag_dump_done,
  			.dump = inet_diag_dump,
  		};
  		return netlink_dump_start(net->diag_nlsk, skb, h, &c);

  	}

  	return inet_diag_cmd_exact(h->nlmsg_type, skb, h, hdrlen,
  				   nlmsg_data(h));

  }

  static
  int inet_diag_handler_get_info(struct sk_buff *skb, struct sock *sk)
  {
  	const struct inet_diag_handler *handler;
  	struct nlmsghdr *nlh;
  	struct nlattr *attr;
  	struct inet_diag_msg *r;
  	void *info = NULL;
  	int err = 0;
  
  	nlh = nlmsg_put(skb, 0, 0, SOCK_DIAG_BY_FAMILY, sizeof(*r), 0);
  	if (!nlh)
  		return -ENOMEM;
  
  	r = nlmsg_data(nlh);
  	memset(r, 0, sizeof(*r));
  	inet_diag_msg_common_fill(r, sk);

  	if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_STREAM)
  		r->id.idiag_sport = inet_sk(sk)->inet_sport;

  	r->idiag_state = sk->sk_state;
  
  	if ((err = nla_put_u8(skb, INET_DIAG_PROTOCOL, sk->sk_protocol))) {
  		nlmsg_cancel(skb, nlh);
  		return err;
  	}
  
  	handler = inet_diag_lock_handler(sk->sk_protocol);
  	if (IS_ERR(handler)) {
  		inet_diag_unlock_handler(handler);
  		nlmsg_cancel(skb, nlh);
  		return PTR_ERR(handler);
  	}
  
  	attr = handler->idiag_info_size

  		? nla_reserve_64bit(skb, INET_DIAG_INFO,
  				    handler->idiag_info_size,
  				    INET_DIAG_PAD)

  		: NULL;
  	if (attr)
  		info = nla_data(attr);
  
  	handler->idiag_get_info(sk, r, info);
  	inet_diag_unlock_handler(handler);
  
  	nlmsg_end(skb, nlh);
  	return 0;
  }

  static const struct sock_diag_handler inet_diag_handler = {

  	.family = AF_INET,

  	.dump = inet_diag_handler_cmd,

  	.get_info = inet_diag_handler_get_info,

  	.destroy = inet_diag_handler_cmd,

  };

  static const struct sock_diag_handler inet6_diag_handler = {

  	.family = AF_INET6,

  	.dump = inet_diag_handler_cmd,

  	.get_info = inet_diag_handler_get_info,

  	.destroy = inet_diag_handler_cmd,

  };

  int inet_diag_register(const struct inet_diag_handler *h)
  {
  	const __u16 type = h->idiag_type;
  	int err = -EINVAL;

  	if (type >= IPPROTO_MAX)

  		goto out;

  	mutex_lock(&inet_diag_table_mutex);

  	err = -EEXIST;

  	if (!inet_diag_table[type]) {

  		inet_diag_table[type] = h;
  		err = 0;
  	}

  	mutex_unlock(&inet_diag_table_mutex);

  out:
  	return err;
  }
  EXPORT_SYMBOL_GPL(inet_diag_register);
  
  void inet_diag_unregister(const struct inet_diag_handler *h)
  {
  	const __u16 type = h->idiag_type;

  	if (type >= IPPROTO_MAX)

  		return;

  	mutex_lock(&inet_diag_table_mutex);

  	inet_diag_table[type] = NULL;

  	mutex_unlock(&inet_diag_table_mutex);

  }
  EXPORT_SYMBOL_GPL(inet_diag_unregister);

  static int __init inet_diag_init(void)

  {

  	const int inet_diag_table_size = (IPPROTO_MAX *

  					  sizeof(struct inet_diag_handler *));
  	int err = -ENOMEM;

  	inet_diag_table = kzalloc(inet_diag_table_size, GFP_KERNEL);

  	if (!inet_diag_table)
  		goto out;

  	err = sock_diag_register(&inet_diag_handler);
  	if (err)
  		goto out_free_nl;
  
  	err = sock_diag_register(&inet6_diag_handler);
  	if (err)
  		goto out_free_inet;

  	sock_diag_register_inet_compat(inet_diag_rcv_msg_compat);

  out:
  	return err;

  
  out_free_inet:
  	sock_diag_unregister(&inet_diag_handler);
  out_free_nl:

  	kfree(inet_diag_table);
  	goto out;

  }

  static void __exit inet_diag_exit(void)

  {

  	sock_diag_unregister(&inet6_diag_handler);
  	sock_diag_unregister(&inet_diag_handler);

  	sock_diag_unregister_inet_compat(inet_diag_rcv_msg_compat);

  	kfree(inet_diag_table);

  }

  module_init(inet_diag_init);
  module_exit(inet_diag_exit);

  MODULE_LICENSE("GPL");

  MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2 /* AF_INET */);
  MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 10 /* AF_INET6 */);