#include <linux/types.h>
  #include <linux/spinlock.h>
  #include <linux/sock_diag.h>
  #include <linux/unix_diag.h>
  #include <linux/skbuff.h>

  #include <linux/module.h>

  #include <net/netlink.h>
  #include <net/af_unix.h>
  #include <net/tcp_states.h>
  
  #define UNIX_DIAG_PUT(skb, attrtype, attrlen) \
  	RTA_DATA(__RTA_PUT(skb, attrtype, attrlen))

  static int sk_diag_dump_name(struct sock *sk, struct sk_buff *nlskb)
  {
  	struct unix_address *addr = unix_sk(sk)->addr;
  	char *s;
  
  	if (addr) {
  		s = UNIX_DIAG_PUT(nlskb, UNIX_DIAG_NAME, addr->len - sizeof(short));
  		memcpy(s, addr->name->sun_path, addr->len - sizeof(short));
  	}
  
  	return 0;
  
  rtattr_failure:
  	return -EMSGSIZE;
  }

  static int sk_diag_dump_vfs(struct sock *sk, struct sk_buff *nlskb)
  {
  	struct dentry *dentry = unix_sk(sk)->dentry;
  	struct unix_diag_vfs *uv;
  
  	if (dentry) {
  		uv = UNIX_DIAG_PUT(nlskb, UNIX_DIAG_VFS, sizeof(*uv));
  		uv->udiag_vfs_ino = dentry->d_inode->i_ino;
  		uv->udiag_vfs_dev = dentry->d_sb->s_dev;
  	}
  
  	return 0;
  
  rtattr_failure:
  	return -EMSGSIZE;
  }

  static int sk_diag_dump_peer(struct sock *sk, struct sk_buff *nlskb)
  {
  	struct sock *peer;
  	int ino;
  
  	peer = unix_peer_get(sk);
  	if (peer) {
  		unix_state_lock(peer);
  		ino = sock_i_ino(peer);
  		unix_state_unlock(peer);
  		sock_put(peer);
  
  		RTA_PUT_U32(nlskb, UNIX_DIAG_PEER, ino);
  	}
  
  	return 0;
  rtattr_failure:
  	return -EMSGSIZE;
  }

  static int sk_diag_dump_icons(struct sock *sk, struct sk_buff *nlskb)
  {
  	struct sk_buff *skb;
  	u32 *buf;
  	int i;
  
  	if (sk->sk_state == TCP_LISTEN) {
  		spin_lock(&sk->sk_receive_queue.lock);

  		buf = UNIX_DIAG_PUT(nlskb, UNIX_DIAG_ICONS,
  				sk->sk_receive_queue.qlen * sizeof(u32));

  		i = 0;
  		skb_queue_walk(&sk->sk_receive_queue, skb) {
  			struct sock *req, *peer;
  
  			req = skb->sk;
  			/*
  			 * The state lock is outer for the same sk's
  			 * queue lock. With the other's queue locked it's
  			 * OK to lock the state.
  			 */
  			unix_state_lock_nested(req);
  			peer = unix_sk(req)->peer;

  			buf[i++] = (peer ? sock_i_ino(peer) : 0);

  			unix_state_unlock(req);
  		}
  		spin_unlock(&sk->sk_receive_queue.lock);
  	}
  
  	return 0;
  
  rtattr_failure:
  	spin_unlock(&sk->sk_receive_queue.lock);
  	return -EMSGSIZE;
  }

  static int sk_diag_show_rqlen(struct sock *sk, struct sk_buff *nlskb)
  {

  	struct unix_diag_rqlen *rql;
  
  	rql = UNIX_DIAG_PUT(nlskb, UNIX_DIAG_RQLEN, sizeof(*rql));
  
  	if (sk->sk_state == TCP_LISTEN) {
  		rql->udiag_rqueue = sk->sk_receive_queue.qlen;
  		rql->udiag_wqueue = sk->sk_max_ack_backlog;
  	} else {
  		rql->udiag_rqueue = (__u32)unix_inq_len(sk);
  		rql->udiag_wqueue = (__u32)unix_outq_len(sk);
  	}

  	return 0;
  
  rtattr_failure:
  	return -EMSGSIZE;
  }

  static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req,
  		u32 pid, u32 seq, u32 flags, int sk_ino)
  {
  	unsigned char *b = skb_tail_pointer(skb);
  	struct nlmsghdr *nlh;
  	struct unix_diag_msg *rep;
  
  	nlh = NLMSG_PUT(skb, pid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rep));
  	nlh->nlmsg_flags = flags;
  
  	rep = NLMSG_DATA(nlh);
  
  	rep->udiag_family = AF_UNIX;
  	rep->udiag_type = sk->sk_type;
  	rep->udiag_state = sk->sk_state;
  	rep->udiag_ino = sk_ino;
  	sock_diag_save_cookie(sk, rep->udiag_cookie);

  	if ((req->udiag_show & UDIAG_SHOW_NAME) &&

  	    sk_diag_dump_name(sk, skb))

  		goto nlmsg_failure;

  	if ((req->udiag_show & UDIAG_SHOW_VFS) &&

  	    sk_diag_dump_vfs(sk, skb))

  		goto nlmsg_failure;

  	if ((req->udiag_show & UDIAG_SHOW_PEER) &&

  	    sk_diag_dump_peer(sk, skb))

  		goto nlmsg_failure;

  	if ((req->udiag_show & UDIAG_SHOW_ICONS) &&

  	    sk_diag_dump_icons(sk, skb))

  		goto nlmsg_failure;

  	if ((req->udiag_show & UDIAG_SHOW_RQLEN) &&

  	    sk_diag_show_rqlen(sk, skb))
  		goto nlmsg_failure;
  
  	if ((req->udiag_show & UDIAG_SHOW_MEMINFO) &&
  	    sock_diag_put_meminfo(sk, skb, UNIX_DIAG_MEMINFO))

  		goto nlmsg_failure;

  	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
  	return skb->len;
  
  nlmsg_failure:
  	nlmsg_trim(skb, b);
  	return -EMSGSIZE;
  }
  
  static int sk_diag_dump(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req,
  		u32 pid, u32 seq, u32 flags)
  {
  	int sk_ino;
  
  	unix_state_lock(sk);
  	sk_ino = sock_i_ino(sk);
  	unix_state_unlock(sk);
  
  	if (!sk_ino)
  		return 0;
  
  	return sk_diag_fill(sk, skb, req, pid, seq, flags, sk_ino);
  }

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

  	struct unix_diag_req *req;
  	int num, s_num, slot, s_slot;
  
  	req = NLMSG_DATA(cb->nlh);
  
  	s_slot = cb->args[0];
  	num = s_num = cb->args[1];
  
  	spin_lock(&unix_table_lock);
  	for (slot = s_slot; slot <= UNIX_HASH_SIZE; s_num = 0, slot++) {
  		struct sock *sk;
  		struct hlist_node *node;
  
  		num = 0;
  		sk_for_each(sk, node, &unix_socket_table[slot]) {
  			if (num < s_num)
  				goto next;
  			if (!(req->udiag_states & (1 << sk->sk_state)))
  				goto next;
  			if (sk_diag_dump(sk, skb, req,

  					 NETLINK_CB(cb->skb).pid,
  					 cb->nlh->nlmsg_seq,
  					 NLM_F_MULTI) < 0)

  				goto done;
  next:
  			num++;
  		}
  	}
  done:
  	spin_unlock(&unix_table_lock);
  	cb->args[0] = slot;
  	cb->args[1] = num;
  
  	return skb->len;

  }

  static struct sock *unix_lookup_by_ino(int ino)
  {
  	int i;
  	struct sock *sk;
  
  	spin_lock(&unix_table_lock);
  	for (i = 0; i <= UNIX_HASH_SIZE; i++) {
  		struct hlist_node *node;
  
  		sk_for_each(sk, node, &unix_socket_table[i])
  			if (ino == sock_i_ino(sk)) {
  				sock_hold(sk);
  				spin_unlock(&unix_table_lock);
  
  				return sk;
  			}
  	}
  
  	spin_unlock(&unix_table_lock);
  	return NULL;
  }

  static int unix_diag_get_exact(struct sk_buff *in_skb,
  			       const struct nlmsghdr *nlh,
  			       struct unix_diag_req *req)
  {

  	int err = -EINVAL;
  	struct sock *sk;
  	struct sk_buff *rep;
  	unsigned int extra_len;
  
  	if (req->udiag_ino == 0)
  		goto out_nosk;
  
  	sk = unix_lookup_by_ino(req->udiag_ino);
  	err = -ENOENT;
  	if (sk == NULL)
  		goto out_nosk;
  
  	err = sock_diag_check_cookie(sk, req->udiag_cookie);
  	if (err)
  		goto out;
  
  	extra_len = 256;
  again:
  	err = -ENOMEM;
  	rep = alloc_skb(NLMSG_SPACE((sizeof(struct unix_diag_msg) + extra_len)),
  			GFP_KERNEL);
  	if (!rep)
  		goto out;
  
  	err = sk_diag_fill(sk, rep, req, NETLINK_CB(in_skb).pid,
  			   nlh->nlmsg_seq, 0, req->udiag_ino);
  	if (err < 0) {
  		kfree_skb(rep);
  		extra_len += 256;
  		if (extra_len >= PAGE_SIZE)
  			goto out;
  
  		goto again;
  	}
  	err = netlink_unicast(sock_diag_nlsk, rep, NETLINK_CB(in_skb).pid,
  			      MSG_DONTWAIT);
  	if (err > 0)
  		err = 0;
  out:
  	if (sk)
  		sock_put(sk);
  out_nosk:
  	return err;

  }
  
  static int unix_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
  {
  	int hdrlen = sizeof(struct unix_diag_req);
  
  	if (nlmsg_len(h) < hdrlen)
  		return -EINVAL;
  
  	if (h->nlmsg_flags & NLM_F_DUMP)
  		return netlink_dump_start(sock_diag_nlsk, skb, h,
  					  unix_diag_dump, NULL, 0);
  	else
  		return unix_diag_get_exact(skb, h, (struct unix_diag_req *)NLMSG_DATA(h));
  }
  
  static struct sock_diag_handler unix_diag_handler = {
  	.family = AF_UNIX,
  	.dump = unix_diag_handler_dump,
  };
  
  static int __init unix_diag_init(void)
  {
  	return sock_diag_register(&unix_diag_handler);
  }
  
  static void __exit unix_diag_exit(void)
  {
  	sock_diag_unregister(&unix_diag_handler);
  }
  
  module_init(unix_diag_init);
  module_exit(unix_diag_exit);
  MODULE_LICENSE("GPL");
  MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 1 /* AF_LOCAL */);