net/tipc/msg.h - kernel/msm-4.9 - Gitiles

 /*
  * net/tipc/msg.h: Include file for TIPC message header routines
  *
  * Copyright (c) 2000-2007, 2014-2015 Ericsson AB
  * Copyright (c) 2005-2008, 2010-2011, Wind River Systems
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  * 3. Neither the names of the copyright holders nor the names of its
  *    contributors may be used to endorse or promote products derived from
  *    this software without specific prior written permission.
  *
  * Alternatively, this software may be distributed under the terms of the
  * GNU General Public License ("GPL") version 2 as published by the Free
  * Software Foundation.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  */

 #ifndef _TIPC_MSG_H
 #define _TIPC_MSG_H

 #include <linux/tipc.h>

 /*
  * Constants and routines used to read and write TIPC payload message headers
  *
  * Note: Some items are also used with TIPC internal message headers
  */
 #define TIPC_VERSION              2
 struct plist;

 /*
  * Payload message users are defined in TIPC's public API:
  * - TIPC_LOW_IMPORTANCE
  * - TIPC_MEDIUM_IMPORTANCE
  * - TIPC_HIGH_IMPORTANCE
  * - TIPC_CRITICAL_IMPORTANCE
  */
 #define TIPC_SYSTEM_IMPORTANCE	4


 /*
  * Payload message types
  */
 #define TIPC_CONN_MSG		0
 #define TIPC_MCAST_MSG		1
 #define TIPC_NAMED_MSG		2
 #define TIPC_DIRECT_MSG		3

 /*
  * Internal message users
  */
 #define  BCAST_PROTOCOL       5
 #define  MSG_BUNDLER          6
 #define  LINK_PROTOCOL        7
 #define  CONN_MANAGER         8
 #define  TUNNEL_PROTOCOL      10
 #define  NAME_DISTRIBUTOR     11
 #define  MSG_FRAGMENTER       12
 #define  LINK_CONFIG          13
 #define  SOCK_WAKEUP          14       /* pseudo user */

 /*
  * Message header sizes
  */
 #define SHORT_H_SIZE              24	/* In-cluster basic payload message */
 #define BASIC_H_SIZE              32	/* Basic payload message */
 #define NAMED_H_SIZE              40	/* Named payload message */
 #define MCAST_H_SIZE              44	/* Multicast payload message */
 #define INT_H_SIZE                40	/* Internal messages */
 #define MIN_H_SIZE                24	/* Smallest legal TIPC header size */
 #define MAX_H_SIZE                60	/* Largest possible TIPC header size */

 #define MAX_MSG_SIZE (MAX_H_SIZE + TIPC_MAX_USER_MSG_SIZE)

 #define TIPC_MEDIA_INFO_OFFSET	5

 /**
  * TIPC message buffer code
  *
  * TIPC message buffer headroom reserves space for the worst-case
  * link-level device header (in case the message is sent off-node).
  *
  * Note: Headroom should be a multiple of 4 to ensure the TIPC header fields
  *       are word aligned for quicker access
  */
 #define BUF_HEADROOM (LL_MAX_HEADER + 48)

 struct tipc_skb_cb {
 	void *handle;
 	struct sk_buff *tail;
 	bool validated;
 	bool wakeup_pending;
 	bool bundling;
 	u16 chain_sz;
 	u16 chain_imp;
 };

 #define TIPC_SKB_CB(__skb) ((struct tipc_skb_cb *)&((__skb)->cb[0]))

 struct tipc_msg {
 	__be32 hdr[15];
 };

 static inline struct tipc_msg *buf_msg(struct sk_buff *skb)
 {
 	return (struct tipc_msg *)skb->data;
 }

 static inline u32 msg_word(struct tipc_msg *m, u32 pos)
 {
 	return ntohl(m->hdr[pos]);
 }

 static inline void msg_set_word(struct tipc_msg *m, u32 w, u32 val)
 {
 	m->hdr[w] = htonl(val);
 }

 static inline u32 msg_bits(struct tipc_msg *m, u32 w, u32 pos, u32 mask)
 {
 	return (msg_word(m, w) >> pos) & mask;
 }

 static inline void msg_set_bits(struct tipc_msg *m, u32 w,
 				u32 pos, u32 mask, u32 val)
 {
 	val = (val & mask) << pos;
 	mask = mask << pos;
 	m->hdr[w] &= ~htonl(mask);
 	m->hdr[w] |= htonl(val);
 }

 static inline void msg_swap_words(struct tipc_msg *msg, u32 a, u32 b)
 {
 	u32 temp = msg->hdr[a];

 	msg->hdr[a] = msg->hdr[b];
 	msg->hdr[b] = temp;
 }

 /*
  * Word 0
  */
 static inline u32 msg_version(struct tipc_msg *m)
 {
 	return msg_bits(m, 0, 29, 7);
 }

 static inline void msg_set_version(struct tipc_msg *m)
 {
 	msg_set_bits(m, 0, 29, 7, TIPC_VERSION);
 }

 static inline u32 msg_user(struct tipc_msg *m)
 {
 	return msg_bits(m, 0, 25, 0xf);
 }

 static inline u32 msg_isdata(struct tipc_msg *m)
 {
 	return msg_user(m) <= TIPC_CRITICAL_IMPORTANCE;
 }

 static inline void msg_set_user(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 0, 25, 0xf, n);
 }

 static inline u32 msg_hdr_sz(struct tipc_msg *m)
 {
 	return msg_bits(m, 0, 21, 0xf) << 2;
 }

 static inline void msg_set_hdr_sz(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 0, 21, 0xf, n>>2);
 }

 static inline u32 msg_size(struct tipc_msg *m)
 {
 	return msg_bits(m, 0, 0, 0x1ffff);
 }

 static inline u32 msg_data_sz(struct tipc_msg *m)
 {
 	return msg_size(m) - msg_hdr_sz(m);
 }

 static inline int msg_non_seq(struct tipc_msg *m)
 {
 	return msg_bits(m, 0, 20, 1);
 }

 static inline void msg_set_non_seq(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 0, 20, 1, n);
 }

 static inline int msg_dest_droppable(struct tipc_msg *m)
 {
 	return msg_bits(m, 0, 19, 1);
 }

 static inline void msg_set_dest_droppable(struct tipc_msg *m, u32 d)
 {
 	msg_set_bits(m, 0, 19, 1, d);
 }

 static inline int msg_src_droppable(struct tipc_msg *m)
 {
 	return msg_bits(m, 0, 18, 1);
 }

 static inline void msg_set_src_droppable(struct tipc_msg *m, u32 d)
 {
 	msg_set_bits(m, 0, 18, 1, d);
 }

 static inline void msg_set_size(struct tipc_msg *m, u32 sz)
 {
 	m->hdr[0] = htonl((msg_word(m, 0) & ~0x1ffff) | sz);
 }

 static inline unchar *msg_data(struct tipc_msg *m)
 {
 	return ((unchar *)m) + msg_hdr_sz(m);
 }

 static inline struct tipc_msg *msg_get_wrapped(struct tipc_msg *m)
 {
 	return (struct tipc_msg *)msg_data(m);
 }

 /*
  * Word 1
  */
 static inline u32 msg_type(struct tipc_msg *m)
 {
 	return msg_bits(m, 1, 29, 0x7);
 }

 static inline void msg_set_type(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 1, 29, 0x7, n);
 }

 static inline u32 msg_named(struct tipc_msg *m)
 {
 	return msg_type(m) == TIPC_NAMED_MSG;
 }

 static inline u32 msg_mcast(struct tipc_msg *m)
 {
 	return msg_type(m) == TIPC_MCAST_MSG;
 }

 static inline u32 msg_connected(struct tipc_msg *m)
 {
 	return msg_type(m) == TIPC_CONN_MSG;
 }

 static inline u32 msg_errcode(struct tipc_msg *m)
 {
 	return msg_bits(m, 1, 25, 0xf);
 }

 static inline void msg_set_errcode(struct tipc_msg *m, u32 err)
 {
 	msg_set_bits(m, 1, 25, 0xf, err);
 }

 static inline u32 msg_reroute_cnt(struct tipc_msg *m)
 {
 	return msg_bits(m, 1, 21, 0xf);
 }

 static inline void msg_incr_reroute_cnt(struct tipc_msg *m)
 {
 	msg_set_bits(m, 1, 21, 0xf, msg_reroute_cnt(m) + 1);
 }

 static inline void msg_reset_reroute_cnt(struct tipc_msg *m)
 {
 	msg_set_bits(m, 1, 21, 0xf, 0);
 }

 static inline u32 msg_lookup_scope(struct tipc_msg *m)
 {
 	return msg_bits(m, 1, 19, 0x3);
 }

 static inline void msg_set_lookup_scope(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 1, 19, 0x3, n);
 }

 static inline u16 msg_bcast_ack(struct tipc_msg *m)
 {
 	return msg_bits(m, 1, 0, 0xffff);
 }

 static inline void msg_set_bcast_ack(struct tipc_msg *m, u16 n)
 {
 	msg_set_bits(m, 1, 0, 0xffff, n);
 }


 /*
  * Word 2
  */
 static inline u16 msg_ack(struct tipc_msg *m)
 {
 	return msg_bits(m, 2, 16, 0xffff);
 }

 static inline void msg_set_ack(struct tipc_msg *m, u16 n)
 {
 	msg_set_bits(m, 2, 16, 0xffff, n);
 }

 static inline u16 msg_seqno(struct tipc_msg *m)
 {
 	return msg_bits(m, 2, 0, 0xffff);
 }

 static inline void msg_set_seqno(struct tipc_msg *m, u16 n)
 {
 	msg_set_bits(m, 2, 0, 0xffff, n);
 }

 /*
  * Words 3-10
  */
 static inline u32 msg_importance(struct tipc_msg *m)
 {
 	int usr = msg_user(m);

 	if (likely((usr <= TIPC_CRITICAL_IMPORTANCE) && !msg_errcode(m)))
 		return usr;
 	if ((usr == MSG_FRAGMENTER) || (usr == MSG_BUNDLER))
 		return msg_bits(m, 5, 13, 0x7);
 	return TIPC_SYSTEM_IMPORTANCE;
 }

 static inline void msg_set_importance(struct tipc_msg *m, u32 i)
 {
 	int usr = msg_user(m);

 	if (likely((usr == MSG_FRAGMENTER) || (usr == MSG_BUNDLER)))
 		msg_set_bits(m, 5, 13, 0x7, i);
 	else if (i < TIPC_SYSTEM_IMPORTANCE)
 		msg_set_user(m, i);
 	else
 		pr_warn("Trying to set illegal importance in message\n");
 }

 static inline u32 msg_prevnode(struct tipc_msg *m)
 {
 	return msg_word(m, 3);
 }

 static inline void msg_set_prevnode(struct tipc_msg *m, u32 a)
 {
 	msg_set_word(m, 3, a);
 }

 static inline u32 msg_origport(struct tipc_msg *m)
 {
 	if (msg_user(m) == MSG_FRAGMENTER)
 		m = msg_get_wrapped(m);
 	return msg_word(m, 4);
 }

 static inline void msg_set_origport(struct tipc_msg *m, u32 p)
 {
 	msg_set_word(m, 4, p);
 }

 static inline u32 msg_destport(struct tipc_msg *m)
 {
 	return msg_word(m, 5);
 }

 static inline void msg_set_destport(struct tipc_msg *m, u32 p)
 {
 	msg_set_word(m, 5, p);
 }

 static inline u32 msg_mc_netid(struct tipc_msg *m)
 {
 	return msg_word(m, 5);
 }

 static inline void msg_set_mc_netid(struct tipc_msg *m, u32 p)
 {
 	msg_set_word(m, 5, p);
 }

 static inline int msg_short(struct tipc_msg *m)
 {
 	return msg_hdr_sz(m) == SHORT_H_SIZE;
 }

 static inline u32 msg_orignode(struct tipc_msg *m)
 {
 	if (likely(msg_short(m)))
 		return msg_prevnode(m);
 	return msg_word(m, 6);
 }

 static inline void msg_set_orignode(struct tipc_msg *m, u32 a)
 {
 	msg_set_word(m, 6, a);
 }

 static inline u32 msg_destnode(struct tipc_msg *m)
 {
 	return msg_word(m, 7);
 }

 static inline void msg_set_destnode(struct tipc_msg *m, u32 a)
 {
 	msg_set_word(m, 7, a);
 }

 static inline u32 msg_nametype(struct tipc_msg *m)
 {
 	return msg_word(m, 8);
 }

 static inline void msg_set_nametype(struct tipc_msg *m, u32 n)
 {
 	msg_set_word(m, 8, n);
 }

 static inline u32 msg_nameinst(struct tipc_msg *m)
 {
 	return msg_word(m, 9);
 }

 static inline u32 msg_namelower(struct tipc_msg *m)
 {
 	return msg_nameinst(m);
 }

 static inline void msg_set_namelower(struct tipc_msg *m, u32 n)
 {
 	msg_set_word(m, 9, n);
 }

 static inline void msg_set_nameinst(struct tipc_msg *m, u32 n)
 {
 	msg_set_namelower(m, n);
 }

 static inline u32 msg_nameupper(struct tipc_msg *m)
 {
 	return msg_word(m, 10);
 }

 static inline void msg_set_nameupper(struct tipc_msg *m, u32 n)
 {
 	msg_set_word(m, 10, n);
 }

 /*
  * Constants and routines used to read and write TIPC internal message headers
  */

 /*
  *  Connection management protocol message types
  */
 #define CONN_PROBE        0
 #define CONN_PROBE_REPLY  1
 #define CONN_ACK          2

 /*
  * Name distributor message types
  */
 #define PUBLICATION       0
 #define WITHDRAWAL        1

 /*
  * Segmentation message types
  */
 #define FIRST_FRAGMENT		0
 #define FRAGMENT		1
 #define LAST_FRAGMENT		2

 /*
  * Link management protocol message types
  */
 #define STATE_MSG		0
 #define RESET_MSG		1
 #define ACTIVATE_MSG		2

 /*
  * Changeover tunnel message types
  */
 #define SYNCH_MSG		0
 #define FAILOVER_MSG		1

 /*
  * Config protocol message types
  */
 #define DSC_REQ_MSG		0
 #define DSC_RESP_MSG		1

 /*
  * Word 1
  */
 static inline u32 msg_seq_gap(struct tipc_msg *m)
 {
 	return msg_bits(m, 1, 16, 0x1fff);
 }

 static inline void msg_set_seq_gap(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 1, 16, 0x1fff, n);
 }

 static inline u32 msg_node_sig(struct tipc_msg *m)
 {
 	return msg_bits(m, 1, 0, 0xffff);
 }

 static inline void msg_set_node_sig(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 1, 0, 0xffff, n);
 }

 static inline u32 msg_node_capabilities(struct tipc_msg *m)
 {
 	return msg_bits(m, 1, 15, 0x1fff);
 }

 static inline void msg_set_node_capabilities(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 1, 15, 0x1fff, n);
 }

 static inline bool msg_dup(struct tipc_msg *m)
 {
 	if (likely(msg_user(m) != TUNNEL_PROTOCOL))
 		return false;
 	if (msg_type(m) != SYNCH_MSG)
 		return false;
 	return true;
 }

 /*
  * Word 2
  */
 static inline u32 msg_dest_domain(struct tipc_msg *m)
 {
 	return msg_word(m, 2);
 }

 static inline void msg_set_dest_domain(struct tipc_msg *m, u32 n)
 {
 	msg_set_word(m, 2, n);
 }

 static inline u32 msg_bcgap_after(struct tipc_msg *m)
 {
 	return msg_bits(m, 2, 16, 0xffff);
 }

 static inline void msg_set_bcgap_after(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 2, 16, 0xffff, n);
 }

 static inline u32 msg_bcgap_to(struct tipc_msg *m)
 {
 	return msg_bits(m, 2, 0, 0xffff);
 }

 static inline void msg_set_bcgap_to(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 2, 0, 0xffff, n);
 }


 /*
  * Word 4
  */
 static inline u32 msg_last_bcast(struct tipc_msg *m)
 {
 	return msg_bits(m, 4, 16, 0xffff);
 }

 static inline void msg_set_last_bcast(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 4, 16, 0xffff, n);
 }

 static inline void msg_set_fragm_no(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 4, 16, 0xffff, n);
 }


 static inline u32 msg_next_sent(struct tipc_msg *m)
 {
 	return msg_bits(m, 4, 0, 0xffff);
 }

 static inline void msg_set_next_sent(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 4, 0, 0xffff, n);
 }

 static inline void msg_set_long_msgno(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 4, 0, 0xffff, n);
 }

 static inline u32 msg_bc_netid(struct tipc_msg *m)
 {
 	return msg_word(m, 4);
 }

 static inline void msg_set_bc_netid(struct tipc_msg *m, u32 id)
 {
 	msg_set_word(m, 4, id);
 }

 static inline u32 msg_link_selector(struct tipc_msg *m)
 {
 	return msg_bits(m, 4, 0, 1);
 }

 static inline void msg_set_link_selector(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 4, 0, 1, n);
 }

 /*
  * Word 5
  */
 static inline u32 msg_session(struct tipc_msg *m)
 {
 	return msg_bits(m, 5, 16, 0xffff);
 }

 static inline void msg_set_session(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 5, 16, 0xffff, n);
 }

 static inline u32 msg_probe(struct tipc_msg *m)
 {
 	return msg_bits(m, 5, 0, 1);
 }

 static inline void msg_set_probe(struct tipc_msg *m, u32 val)
 {
 	msg_set_bits(m, 5, 0, 1, val);
 }

 static inline char msg_net_plane(struct tipc_msg *m)
 {
 	return msg_bits(m, 5, 1, 7) + 'A';
 }

 static inline void msg_set_net_plane(struct tipc_msg *m, char n)
 {
 	msg_set_bits(m, 5, 1, 7, (n - 'A'));
 }

 static inline u32 msg_linkprio(struct tipc_msg *m)
 {
 	return msg_bits(m, 5, 4, 0x1f);
 }

 static inline void msg_set_linkprio(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 5, 4, 0x1f, n);
 }

 static inline u32 msg_bearer_id(struct tipc_msg *m)
 {
 	return msg_bits(m, 5, 9, 0x7);
 }

 static inline void msg_set_bearer_id(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 5, 9, 0x7, n);
 }

 static inline u32 msg_redundant_link(struct tipc_msg *m)
 {
 	return msg_bits(m, 5, 12, 0x1);
 }

 static inline void msg_set_redundant_link(struct tipc_msg *m, u32 r)
 {
 	msg_set_bits(m, 5, 12, 0x1, r);
 }

 static inline char *msg_media_addr(struct tipc_msg *m)
 {
 	return (char *)&m->hdr[TIPC_MEDIA_INFO_OFFSET];
 }

 /*
  * Word 9
  */
 static inline u32 msg_msgcnt(struct tipc_msg *m)
 {
 	return msg_bits(m, 9, 16, 0xffff);
 }

 static inline void msg_set_msgcnt(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 9, 16, 0xffff, n);
 }

 static inline u32 msg_bcast_tag(struct tipc_msg *m)
 {
 	return msg_bits(m, 9, 16, 0xffff);
 }

 static inline void msg_set_bcast_tag(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 9, 16, 0xffff, n);
 }

 static inline u32 msg_max_pkt(struct tipc_msg *m)
 {
 	return msg_bits(m, 9, 16, 0xffff) * 4;
 }

 static inline void msg_set_max_pkt(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 9, 16, 0xffff, (n / 4));
 }

 static inline u32 msg_link_tolerance(struct tipc_msg *m)
 {
 	return msg_bits(m, 9, 0, 0xffff);
 }

 static inline void msg_set_link_tolerance(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 9, 0, 0xffff, n);
 }

 struct sk_buff *tipc_buf_acquire(u32 size);
 bool tipc_msg_validate(struct sk_buff *skb);
 bool tipc_msg_reverse(u32 own_addr, struct sk_buff *buf, u32 *dnode,
 		      int err);
 void tipc_msg_init(u32 own_addr, struct tipc_msg *m, u32 user, u32 type,
 		   u32 hsize, u32 destnode);
 struct sk_buff *tipc_msg_create(uint user, uint type, uint hdr_sz,
 				uint data_sz, u32 dnode, u32 onode,
 				u32 dport, u32 oport, int errcode);
 int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf);
 bool tipc_msg_bundle(struct sk_buff *skb, struct tipc_msg *msg, u32 mtu);
 bool tipc_msg_make_bundle(struct sk_buff **skb, struct tipc_msg *msg,
 			  u32 mtu, u32 dnode);
 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos);
 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m,
 		   int offset, int dsz, int mtu, struct sk_buff_head *list);
 bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, u32 *dnode,
 			  int *err);
 struct sk_buff *tipc_msg_reassemble(struct sk_buff_head *list);

 static inline u16 buf_seqno(struct sk_buff *skb)
 {
 	return msg_seqno(buf_msg(skb));
 }

 /* tipc_skb_peek(): peek and reserve first buffer in list
  * @list: list to be peeked in
  * Returns pointer to first buffer in list, if any
  */
 static inline struct sk_buff *tipc_skb_peek(struct sk_buff_head *list,
 					    spinlock_t *lock)
 {
 	struct sk_buff *skb;

 	spin_lock_bh(lock);
 	skb = skb_peek(list);
 	if (skb)
 		skb_get(skb);
 	spin_unlock_bh(lock);
 	return skb;
 }

 /* tipc_skb_peek_port(): find a destination port, ignoring all destinations
  *                       up to and including 'filter'.
  * Note: ignoring previously tried destinations minimizes the risk of
  *       contention on the socket lock
  * @list: list to be peeked in
  * @filter: last destination to be ignored from search
  * Returns a destination port number, of applicable.
  */
 static inline u32 tipc_skb_peek_port(struct sk_buff_head *list, u32 filter)
 {
 	struct sk_buff *skb;
 	u32 dport = 0;
 	bool ignore = true;

 	spin_lock_bh(&list->lock);
 	skb_queue_walk(list, skb) {
 		dport = msg_destport(buf_msg(skb));
 		if (!filter || skb_queue_is_last(list, skb))
 			break;
 		if (dport == filter)
 			ignore = false;
 		else if (!ignore)
 			break;
 	}
 	spin_unlock_bh(&list->lock);
 	return dport;
 }

 /* tipc_skb_dequeue(): unlink first buffer with dest 'dport' from list
  * @list: list to be unlinked from
  * @dport: selection criteria for buffer to unlink
  */
 static inline struct sk_buff *tipc_skb_dequeue(struct sk_buff_head *list,
 					       u32 dport)
 {
 	struct sk_buff *_skb, *tmp, *skb = NULL;

 	spin_lock_bh(&list->lock);
 	skb_queue_walk_safe(list, _skb, tmp) {
 		if (msg_destport(buf_msg(_skb)) == dport) {
 			__skb_unlink(_skb, list);
 			skb = _skb;
 			break;
 		}
 	}
 	spin_unlock_bh(&list->lock);
 	return skb;
 }

 /* tipc_skb_queue_tail(): add buffer to tail of list;
  * @list: list to be appended to
  * @skb: buffer to append. Always appended
  * @dport: the destination port of the buffer
  * returns true if dport differs from previous destination
  */
 static inline bool tipc_skb_queue_tail(struct sk_buff_head *list,
 				       struct sk_buff *skb, u32 dport)
 {
 	struct sk_buff *_skb = NULL;
 	bool rv = false;

 	spin_lock_bh(&list->lock);
 	_skb = skb_peek_tail(list);
 	if (!_skb || (msg_destport(buf_msg(_skb)) != dport) ||
 	    (skb_queue_len(list) > 32))
 		rv = true;
 	__skb_queue_tail(list, skb);
 	spin_unlock_bh(&list->lock);
 	return rv;
 }

 #endif
	/*
	* net/tipc/msg.h: Include file for TIPC message header routines
	*
	* Copyright (c) 2000-2007, 2014-2015 Ericsson AB
	* Copyright (c) 2005-2008, 2010-2011, Wind River Systems
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	* 3. Neither the names of the copyright holders nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* Alternatively, this software may be distributed under the terms of the
	* GNU General Public License ("GPL") version 2 as published by the Free
	* Software Foundation.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
	* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
	* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
	* POSSIBILITY OF SUCH DAMAGE.
	*/

	#ifndef _TIPC_MSG_H
	#define _TIPC_MSG_H

	#include <linux/tipc.h>

	/*
	* Constants and routines used to read and write TIPC payload message headers
	*
	* Note: Some items are also used with TIPC internal message headers
	*/
	#define TIPC_VERSION 2
	struct plist;

	/*
	* Payload message users are defined in TIPC's public API:
	* - TIPC_LOW_IMPORTANCE
	* - TIPC_MEDIUM_IMPORTANCE
	* - TIPC_HIGH_IMPORTANCE
	* - TIPC_CRITICAL_IMPORTANCE
	*/
	#define TIPC_SYSTEM_IMPORTANCE 4


	/*
	* Payload message types
	*/
	#define TIPC_CONN_MSG 0
	#define TIPC_MCAST_MSG 1
	#define TIPC_NAMED_MSG 2
	#define TIPC_DIRECT_MSG 3

	/*
	* Internal message users
	*/
	#define BCAST_PROTOCOL 5
	#define MSG_BUNDLER 6
	#define LINK_PROTOCOL 7
	#define CONN_MANAGER 8
	#define TUNNEL_PROTOCOL 10
	#define NAME_DISTRIBUTOR 11
	#define MSG_FRAGMENTER 12
	#define LINK_CONFIG 13
	#define SOCK_WAKEUP 14 /* pseudo user */

	/*
	* Message header sizes
	*/
	#define SHORT_H_SIZE 24 /* In-cluster basic payload message */
	#define BASIC_H_SIZE 32 /* Basic payload message */
	#define NAMED_H_SIZE 40 /* Named payload message */
	#define MCAST_H_SIZE 44 /* Multicast payload message */
	#define INT_H_SIZE 40 /* Internal messages */
	#define MIN_H_SIZE 24 /* Smallest legal TIPC header size */
	#define MAX_H_SIZE 60 /* Largest possible TIPC header size */

	#define MAX_MSG_SIZE (MAX_H_SIZE + TIPC_MAX_USER_MSG_SIZE)

	#define TIPC_MEDIA_INFO_OFFSET 5

	/**
	* TIPC message buffer code
	*
	* TIPC message buffer headroom reserves space for the worst-case
	* link-level device header (in case the message is sent off-node).
	*
	* Note: Headroom should be a multiple of 4 to ensure the TIPC header fields
	* are word aligned for quicker access
	*/
	#define BUF_HEADROOM (LL_MAX_HEADER + 48)

	struct tipc_skb_cb {
	void *handle;
	struct sk_buff *tail;
	bool validated;
	bool wakeup_pending;
	bool bundling;
	u16 chain_sz;
	u16 chain_imp;
	};

	#define TIPC_SKB_CB(__skb) ((struct tipc_skb_cb *)&((__skb)->cb[0]))

	struct tipc_msg {
	__be32 hdr[15];
	};

	static inline struct tipc_msg buf_msg(struct sk_buff skb)
	{
	return (struct tipc_msg *)skb->data;
	}

	static inline u32 msg_word(struct tipc_msg *m, u32 pos)
	{
	return ntohl(m->hdr[pos]);
	}

	static inline void msg_set_word(struct tipc_msg *m, u32 w, u32 val)
	{
	m->hdr[w] = htonl(val);
	}

	static inline u32 msg_bits(struct tipc_msg *m, u32 w, u32 pos, u32 mask)
	{
	return (msg_word(m, w) >> pos) & mask;
	}

	static inline void msg_set_bits(struct tipc_msg *m, u32 w,
	u32 pos, u32 mask, u32 val)
	{
	val = (val & mask) << pos;
	mask = mask << pos;
	m->hdr[w] &= ~htonl(mask);
	m->hdr[w] \|= htonl(val);
	}

	static inline void msg_swap_words(struct tipc_msg *msg, u32 a, u32 b)
	{
	u32 temp = msg->hdr[a];

	msg->hdr[a] = msg->hdr[b];
	msg->hdr[b] = temp;
	}

	/*
	* Word 0
	*/
	static inline u32 msg_version(struct tipc_msg *m)
	{
	return msg_bits(m, 0, 29, 7);
	}

	static inline void msg_set_version(struct tipc_msg *m)
	{
	msg_set_bits(m, 0, 29, 7, TIPC_VERSION);
	}

	static inline u32 msg_user(struct tipc_msg *m)
	{
	return msg_bits(m, 0, 25, 0xf);
	}

	static inline u32 msg_isdata(struct tipc_msg *m)
	{
	return msg_user(m) <= TIPC_CRITICAL_IMPORTANCE;
	}

	static inline void msg_set_user(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 0, 25, 0xf, n);
	}

	static inline u32 msg_hdr_sz(struct tipc_msg *m)
	{
	return msg_bits(m, 0, 21, 0xf) << 2;
	}

	static inline void msg_set_hdr_sz(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 0, 21, 0xf, n>>2);
	}

	static inline u32 msg_size(struct tipc_msg *m)
	{
	return msg_bits(m, 0, 0, 0x1ffff);
	}

	static inline u32 msg_data_sz(struct tipc_msg *m)
	{
	return msg_size(m) - msg_hdr_sz(m);
	}

	static inline int msg_non_seq(struct tipc_msg *m)
	{
	return msg_bits(m, 0, 20, 1);
	}

	static inline void msg_set_non_seq(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 0, 20, 1, n);
	}

	static inline int msg_dest_droppable(struct tipc_msg *m)
	{
	return msg_bits(m, 0, 19, 1);
	}

	static inline void msg_set_dest_droppable(struct tipc_msg *m, u32 d)
	{
	msg_set_bits(m, 0, 19, 1, d);
	}

	static inline int msg_src_droppable(struct tipc_msg *m)
	{
	return msg_bits(m, 0, 18, 1);
	}

	static inline void msg_set_src_droppable(struct tipc_msg *m, u32 d)
	{
	msg_set_bits(m, 0, 18, 1, d);
	}

	static inline void msg_set_size(struct tipc_msg *m, u32 sz)
	{
	m->hdr[0] = htonl((msg_word(m, 0) & ~0x1ffff) \| sz);
	}

	static inline unchar msg_data(struct tipc_msg m)
	{
	return ((unchar *)m) + msg_hdr_sz(m);
	}

	static inline struct tipc_msg msg_get_wrapped(struct tipc_msg m)
	{
	return (struct tipc_msg *)msg_data(m);
	}

	/*
	* Word 1
	*/
	static inline u32 msg_type(struct tipc_msg *m)
	{
	return msg_bits(m, 1, 29, 0x7);
	}

	static inline void msg_set_type(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 1, 29, 0x7, n);
	}

	static inline u32 msg_named(struct tipc_msg *m)
	{
	return msg_type(m) == TIPC_NAMED_MSG;
	}

	static inline u32 msg_mcast(struct tipc_msg *m)
	{
	return msg_type(m) == TIPC_MCAST_MSG;
	}

	static inline u32 msg_connected(struct tipc_msg *m)
	{
	return msg_type(m) == TIPC_CONN_MSG;
	}

	static inline u32 msg_errcode(struct tipc_msg *m)
	{
	return msg_bits(m, 1, 25, 0xf);
	}

	static inline void msg_set_errcode(struct tipc_msg *m, u32 err)
	{
	msg_set_bits(m, 1, 25, 0xf, err);
	}

	static inline u32 msg_reroute_cnt(struct tipc_msg *m)
	{
	return msg_bits(m, 1, 21, 0xf);
	}

	static inline void msg_incr_reroute_cnt(struct tipc_msg *m)
	{
	msg_set_bits(m, 1, 21, 0xf, msg_reroute_cnt(m) + 1);
	}

	static inline void msg_reset_reroute_cnt(struct tipc_msg *m)
	{
	msg_set_bits(m, 1, 21, 0xf, 0);
	}

	static inline u32 msg_lookup_scope(struct tipc_msg *m)
	{
	return msg_bits(m, 1, 19, 0x3);
	}

	static inline void msg_set_lookup_scope(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 1, 19, 0x3, n);
	}

	static inline u16 msg_bcast_ack(struct tipc_msg *m)
	{
	return msg_bits(m, 1, 0, 0xffff);
	}

	static inline void msg_set_bcast_ack(struct tipc_msg *m, u16 n)
	{
	msg_set_bits(m, 1, 0, 0xffff, n);
	}


	/*
	* Word 2
	*/
	static inline u16 msg_ack(struct tipc_msg *m)
	{
	return msg_bits(m, 2, 16, 0xffff);
	}

	static inline void msg_set_ack(struct tipc_msg *m, u16 n)
	{
	msg_set_bits(m, 2, 16, 0xffff, n);
	}

	static inline u16 msg_seqno(struct tipc_msg *m)
	{
	return msg_bits(m, 2, 0, 0xffff);
	}

	static inline void msg_set_seqno(struct tipc_msg *m, u16 n)
	{
	msg_set_bits(m, 2, 0, 0xffff, n);
	}

	/*
	* Words 3-10
	*/
	static inline u32 msg_importance(struct tipc_msg *m)
	{
	int usr = msg_user(m);

	if (likely((usr <= TIPC_CRITICAL_IMPORTANCE) && !msg_errcode(m)))
	return usr;
	if ((usr == MSG_FRAGMENTER) \|\| (usr == MSG_BUNDLER))
	return msg_bits(m, 5, 13, 0x7);
	return TIPC_SYSTEM_IMPORTANCE;
	}

	static inline void msg_set_importance(struct tipc_msg *m, u32 i)
	{
	int usr = msg_user(m);

	if (likely((usr == MSG_FRAGMENTER) \|\| (usr == MSG_BUNDLER)))
	msg_set_bits(m, 5, 13, 0x7, i);
	else if (i < TIPC_SYSTEM_IMPORTANCE)
	msg_set_user(m, i);
	else
	pr_warn("Trying to set illegal importance in message\n");
	}

	static inline u32 msg_prevnode(struct tipc_msg *m)
	{
	return msg_word(m, 3);
	}

	static inline void msg_set_prevnode(struct tipc_msg *m, u32 a)
	{
	msg_set_word(m, 3, a);
	}

	static inline u32 msg_origport(struct tipc_msg *m)
	{
	if (msg_user(m) == MSG_FRAGMENTER)
	m = msg_get_wrapped(m);
	return msg_word(m, 4);
	}

	static inline void msg_set_origport(struct tipc_msg *m, u32 p)
	{
	msg_set_word(m, 4, p);
	}

	static inline u32 msg_destport(struct tipc_msg *m)
	{
	return msg_word(m, 5);
	}

	static inline void msg_set_destport(struct tipc_msg *m, u32 p)
	{
	msg_set_word(m, 5, p);
	}

	static inline u32 msg_mc_netid(struct tipc_msg *m)
	{
	return msg_word(m, 5);
	}

	static inline void msg_set_mc_netid(struct tipc_msg *m, u32 p)
	{
	msg_set_word(m, 5, p);
	}

	static inline int msg_short(struct tipc_msg *m)
	{
	return msg_hdr_sz(m) == SHORT_H_SIZE;
	}

	static inline u32 msg_orignode(struct tipc_msg *m)
	{
	if (likely(msg_short(m)))
	return msg_prevnode(m);
	return msg_word(m, 6);
	}

	static inline void msg_set_orignode(struct tipc_msg *m, u32 a)
	{
	msg_set_word(m, 6, a);
	}

	static inline u32 msg_destnode(struct tipc_msg *m)
	{
	return msg_word(m, 7);
	}

	static inline void msg_set_destnode(struct tipc_msg *m, u32 a)
	{
	msg_set_word(m, 7, a);
	}

	static inline u32 msg_nametype(struct tipc_msg *m)
	{
	return msg_word(m, 8);
	}

	static inline void msg_set_nametype(struct tipc_msg *m, u32 n)
	{
	msg_set_word(m, 8, n);
	}

	static inline u32 msg_nameinst(struct tipc_msg *m)
	{
	return msg_word(m, 9);
	}

	static inline u32 msg_namelower(struct tipc_msg *m)
	{
	return msg_nameinst(m);
	}

	static inline void msg_set_namelower(struct tipc_msg *m, u32 n)
	{
	msg_set_word(m, 9, n);
	}

	static inline void msg_set_nameinst(struct tipc_msg *m, u32 n)
	{
	msg_set_namelower(m, n);
	}

	static inline u32 msg_nameupper(struct tipc_msg *m)
	{
	return msg_word(m, 10);
	}

	static inline void msg_set_nameupper(struct tipc_msg *m, u32 n)
	{
	msg_set_word(m, 10, n);
	}

	/*
	* Constants and routines used to read and write TIPC internal message headers
	*/

	/*
	* Connection management protocol message types
	*/
	#define CONN_PROBE 0
	#define CONN_PROBE_REPLY 1
	#define CONN_ACK 2

	/*
	* Name distributor message types
	*/
	#define PUBLICATION 0
	#define WITHDRAWAL 1

	/*
	* Segmentation message types
	*/
	#define FIRST_FRAGMENT 0
	#define FRAGMENT 1
	#define LAST_FRAGMENT 2

	/*
	* Link management protocol message types
	*/
	#define STATE_MSG 0
	#define RESET_MSG 1
	#define ACTIVATE_MSG 2

	/*
	* Changeover tunnel message types
	*/
	#define SYNCH_MSG 0
	#define FAILOVER_MSG 1

	/*
	* Config protocol message types
	*/
	#define DSC_REQ_MSG 0
	#define DSC_RESP_MSG 1

	/*
	* Word 1
	*/
	static inline u32 msg_seq_gap(struct tipc_msg *m)
	{
	return msg_bits(m, 1, 16, 0x1fff);
	}

	static inline void msg_set_seq_gap(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 1, 16, 0x1fff, n);
	}

	static inline u32 msg_node_sig(struct tipc_msg *m)
	{
	return msg_bits(m, 1, 0, 0xffff);
	}

	static inline void msg_set_node_sig(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 1, 0, 0xffff, n);
	}

	static inline u32 msg_node_capabilities(struct tipc_msg *m)
	{
	return msg_bits(m, 1, 15, 0x1fff);
	}

	static inline void msg_set_node_capabilities(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 1, 15, 0x1fff, n);
	}

	static inline bool msg_dup(struct tipc_msg *m)
	{
	if (likely(msg_user(m) != TUNNEL_PROTOCOL))
	return false;
	if (msg_type(m) != SYNCH_MSG)
	return false;
	return true;
	}

	/*
	* Word 2
	*/
	static inline u32 msg_dest_domain(struct tipc_msg *m)
	{
	return msg_word(m, 2);
	}

	static inline void msg_set_dest_domain(struct tipc_msg *m, u32 n)
	{
	msg_set_word(m, 2, n);
	}

	static inline u32 msg_bcgap_after(struct tipc_msg *m)
	{
	return msg_bits(m, 2, 16, 0xffff);
	}

	static inline void msg_set_bcgap_after(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 2, 16, 0xffff, n);
	}

	static inline u32 msg_bcgap_to(struct tipc_msg *m)
	{
	return msg_bits(m, 2, 0, 0xffff);
	}

	static inline void msg_set_bcgap_to(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 2, 0, 0xffff, n);
	}


	/*
	* Word 4
	*/
	static inline u32 msg_last_bcast(struct tipc_msg *m)
	{
	return msg_bits(m, 4, 16, 0xffff);
	}

	static inline void msg_set_last_bcast(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 4, 16, 0xffff, n);
	}

	static inline void msg_set_fragm_no(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 4, 16, 0xffff, n);
	}


	static inline u32 msg_next_sent(struct tipc_msg *m)
	{
	return msg_bits(m, 4, 0, 0xffff);
	}

	static inline void msg_set_next_sent(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 4, 0, 0xffff, n);
	}

	static inline void msg_set_long_msgno(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 4, 0, 0xffff, n);
	}

	static inline u32 msg_bc_netid(struct tipc_msg *m)
	{
	return msg_word(m, 4);
	}

	static inline void msg_set_bc_netid(struct tipc_msg *m, u32 id)
	{
	msg_set_word(m, 4, id);
	}

	static inline u32 msg_link_selector(struct tipc_msg *m)
	{
	return msg_bits(m, 4, 0, 1);
	}

	static inline void msg_set_link_selector(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 4, 0, 1, n);
	}

	/*
	* Word 5
	*/
	static inline u32 msg_session(struct tipc_msg *m)
	{
	return msg_bits(m, 5, 16, 0xffff);
	}

	static inline void msg_set_session(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 5, 16, 0xffff, n);
	}

	static inline u32 msg_probe(struct tipc_msg *m)
	{
	return msg_bits(m, 5, 0, 1);
	}

	static inline void msg_set_probe(struct tipc_msg *m, u32 val)
	{
	msg_set_bits(m, 5, 0, 1, val);
	}

	static inline char msg_net_plane(struct tipc_msg *m)
	{
	return msg_bits(m, 5, 1, 7) + 'A';
	}

	static inline void msg_set_net_plane(struct tipc_msg *m, char n)
	{
	msg_set_bits(m, 5, 1, 7, (n - 'A'));
	}

	static inline u32 msg_linkprio(struct tipc_msg *m)
	{
	return msg_bits(m, 5, 4, 0x1f);
	}

	static inline void msg_set_linkprio(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 5, 4, 0x1f, n);
	}

	static inline u32 msg_bearer_id(struct tipc_msg *m)
	{
	return msg_bits(m, 5, 9, 0x7);
	}

	static inline void msg_set_bearer_id(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 5, 9, 0x7, n);
	}

	static inline u32 msg_redundant_link(struct tipc_msg *m)
	{
	return msg_bits(m, 5, 12, 0x1);
	}

	static inline void msg_set_redundant_link(struct tipc_msg *m, u32 r)
	{
	msg_set_bits(m, 5, 12, 0x1, r);
	}

	static inline char msg_media_addr(struct tipc_msg m)
	{
	return (char *)&m->hdr[TIPC_MEDIA_INFO_OFFSET];
	}

	/*
	* Word 9
	*/
	static inline u32 msg_msgcnt(struct tipc_msg *m)
	{
	return msg_bits(m, 9, 16, 0xffff);
	}

	static inline void msg_set_msgcnt(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 9, 16, 0xffff, n);
	}

	static inline u32 msg_bcast_tag(struct tipc_msg *m)
	{
	return msg_bits(m, 9, 16, 0xffff);
	}

	static inline void msg_set_bcast_tag(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 9, 16, 0xffff, n);
	}

	static inline u32 msg_max_pkt(struct tipc_msg *m)
	{
	return msg_bits(m, 9, 16, 0xffff) * 4;
	}

	static inline void msg_set_max_pkt(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 9, 16, 0xffff, (n / 4));
	}

	static inline u32 msg_link_tolerance(struct tipc_msg *m)
	{
	return msg_bits(m, 9, 0, 0xffff);
	}

	static inline void msg_set_link_tolerance(struct tipc_msg *m, u32 n)
	{
	msg_set_bits(m, 9, 0, 0xffff, n);
	}

	struct sk_buff *tipc_buf_acquire(u32 size);
	bool tipc_msg_validate(struct sk_buff *skb);
	bool tipc_msg_reverse(u32 own_addr, struct sk_buff buf, u32 dnode,
	int err);
	void tipc_msg_init(u32 own_addr, struct tipc_msg *m, u32 user, u32 type,
	u32 hsize, u32 destnode);
	struct sk_buff *tipc_msg_create(uint user, uint type, uint hdr_sz,
	uint data_sz, u32 dnode, u32 onode,
	u32 dport, u32 oport, int errcode);
	int tipc_buf_append(struct sk_buff headbuf, struct sk_buff buf);
	bool tipc_msg_bundle(struct sk_buff skb, struct tipc_msg msg, u32 mtu);
	bool tipc_msg_make_bundle(struct sk_buff *skb, struct tipc_msg msg,
	u32 mtu, u32 dnode);
	bool tipc_msg_extract(struct sk_buff skb, struct sk_buff iskb, int pos);
	int tipc_msg_build(struct tipc_msg mhdr, struct msghdr m,
	int offset, int dsz, int mtu, struct sk_buff_head *list);
	bool tipc_msg_lookup_dest(struct net net, struct sk_buff skb, u32 *dnode,
	int *err);
	struct sk_buff tipc_msg_reassemble(struct sk_buff_head list);

	static inline u16 buf_seqno(struct sk_buff *skb)
	{
	return msg_seqno(buf_msg(skb));
	}

	/* tipc_skb_peek(): peek and reserve first buffer in list
	* @list: list to be peeked in
	* Returns pointer to first buffer in list, if any
	*/
	static inline struct sk_buff tipc_skb_peek(struct sk_buff_head list,
	spinlock_t *lock)
	{
	struct sk_buff *skb;

	spin_lock_bh(lock);
	skb = skb_peek(list);
	if (skb)
	skb_get(skb);
	spin_unlock_bh(lock);
	return skb;
	}

	/* tipc_skb_peek_port(): find a destination port, ignoring all destinations
	* up to and including 'filter'.
	* Note: ignoring previously tried destinations minimizes the risk of
	* contention on the socket lock
	* @list: list to be peeked in
	* @filter: last destination to be ignored from search
	* Returns a destination port number, of applicable.
	*/
	static inline u32 tipc_skb_peek_port(struct sk_buff_head *list, u32 filter)
	{
	struct sk_buff *skb;
	u32 dport = 0;
	bool ignore = true;

	spin_lock_bh(&list->lock);
	skb_queue_walk(list, skb) {
	dport = msg_destport(buf_msg(skb));
	if (!filter \|\| skb_queue_is_last(list, skb))
	break;
	if (dport == filter)
	ignore = false;
	else if (!ignore)
	break;
	}
	spin_unlock_bh(&list->lock);
	return dport;
	}

	/* tipc_skb_dequeue(): unlink first buffer with dest 'dport' from list
	* @list: list to be unlinked from
	* @dport: selection criteria for buffer to unlink
	*/
	static inline struct sk_buff tipc_skb_dequeue(struct sk_buff_head list,
	u32 dport)
	{
	struct sk_buff _skb, tmp, *skb = NULL;

	spin_lock_bh(&list->lock);
	skb_queue_walk_safe(list, _skb, tmp) {
	if (msg_destport(buf_msg(_skb)) == dport) {
	__skb_unlink(_skb, list);
	skb = _skb;
	break;
	}
	}
	spin_unlock_bh(&list->lock);
	return skb;
	}

	/* tipc_skb_queue_tail(): add buffer to tail of list;
	* @list: list to be appended to
	* @skb: buffer to append. Always appended
	* @dport: the destination port of the buffer
	* returns true if dport differs from previous destination
	*/
	static inline bool tipc_skb_queue_tail(struct sk_buff_head *list,
	struct sk_buff *skb, u32 dport)
	{
	struct sk_buff *_skb = NULL;
	bool rv = false;

	spin_lock_bh(&list->lock);
	_skb = skb_peek_tail(list);
	if (!_skb \|\| (msg_destport(buf_msg(_skb)) != dport) \|\|
	(skb_queue_len(list) > 32))
	rv = true;
	__skb_queue_tail(list, skb);
	spin_unlock_bh(&list->lock);
	return rv;
	}

	#endif