net/tipc/msg.c - LeafOS-Devices/android_kernel_samsung_universal7904 - Gitiles

 /*
  * net/tipc/msg.c: TIPC message header routines
  *
  * Copyright (c) 2000-2006, 2014-2015, Ericsson AB
  * Copyright (c) 2005, 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.
  */

 #include <net/sock.h>
 #include "core.h"
 #include "msg.h"
 #include "addr.h"
 #include "name_table.h"

 #define MAX_FORWARD_SIZE 1024

 static unsigned int align(unsigned int i)
 {
 	return (i + 3) & ~3u;
 }

 /**
  * tipc_buf_acquire - creates a TIPC message buffer
  * @size: message size (including TIPC header)
  *
  * Returns a new buffer with data pointers set to the specified size.
  *
  * NOTE: Headroom is reserved to allow prepending of a data link header.
  *       There may also be unrequested tailroom present at the buffer's end.
  */
 struct sk_buff *tipc_buf_acquire(u32 size)
 {
 	struct sk_buff *skb;
 	unsigned int buf_size = (BUF_HEADROOM + size + 3) & ~3u;

 	skb = alloc_skb_fclone(buf_size, GFP_ATOMIC);
 	if (skb) {
 		skb_reserve(skb, BUF_HEADROOM);
 		skb_put(skb, size);
 		skb->next = NULL;
 	}
 	return skb;
 }

 void tipc_msg_init(u32 own_node, struct tipc_msg *m, u32 user, u32 type,
 		   u32 hsize, u32 dnode)
 {
 	memset(m, 0, hsize);
 	msg_set_version(m);
 	msg_set_user(m, user);
 	msg_set_hdr_sz(m, hsize);
 	msg_set_size(m, hsize);
 	msg_set_prevnode(m, own_node);
 	msg_set_type(m, type);
 	if (hsize > SHORT_H_SIZE) {
 		msg_set_orignode(m, own_node);
 		msg_set_destnode(m, dnode);
 	}
 }

 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)
 {
 	struct tipc_msg *msg;
 	struct sk_buff *buf;

 	buf = tipc_buf_acquire(hdr_sz + data_sz);
 	if (unlikely(!buf))
 		return NULL;

 	msg = buf_msg(buf);
 	tipc_msg_init(onode, msg, user, type, hdr_sz, dnode);
 	msg_set_size(msg, hdr_sz + data_sz);
 	msg_set_origport(msg, oport);
 	msg_set_destport(msg, dport);
 	msg_set_errcode(msg, errcode);
 	if (hdr_sz > SHORT_H_SIZE) {
 		msg_set_orignode(msg, onode);
 		msg_set_destnode(msg, dnode);
 	}
 	return buf;
 }

 /* tipc_buf_append(): Append a buffer to the fragment list of another buffer
  * @*headbuf: in:  NULL for first frag, otherwise value returned from prev call
  *            out: set when successful non-complete reassembly, otherwise NULL
  * @*buf:     in:  the buffer to append. Always defined
  *            out: head buf after successful complete reassembly, otherwise NULL
  * Returns 1 when reassembly complete, otherwise 0
  */
 int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
 {
 	struct sk_buff *head = *headbuf;
 	struct sk_buff *frag = *buf;
 	struct sk_buff *tail = NULL;
 	struct tipc_msg *msg;
 	u32 fragid;
 	int delta;
 	bool headstolen;

 	if (!frag)
 		goto err;

 	msg = buf_msg(frag);
 	fragid = msg_type(msg);
 	frag->next = NULL;
 	skb_pull(frag, msg_hdr_sz(msg));

 	if (fragid == FIRST_FRAGMENT) {
 		if (unlikely(head))
 			goto err;
 		if (unlikely(skb_unclone(frag, GFP_ATOMIC)))
 			goto err;
 		head = *headbuf = frag;
 		*buf = NULL;
 		TIPC_SKB_CB(head)->tail = NULL;
 		if (skb_is_nonlinear(head)) {
 			skb_walk_frags(head, tail) {
 				TIPC_SKB_CB(head)->tail = tail;
 			}
 		} else {
 			skb_frag_list_init(head);
 		}
 		return 0;
 	}

 	if (!head)
 		goto err;

 	if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
 		kfree_skb_partial(frag, headstolen);
 	} else {
 		tail = TIPC_SKB_CB(head)->tail;
 		if (!skb_has_frag_list(head))
 			skb_shinfo(head)->frag_list = frag;
 		else
 			tail->next = frag;
 		head->truesize += frag->truesize;
 		head->data_len += frag->len;
 		head->len += frag->len;
 		TIPC_SKB_CB(head)->tail = frag;
 	}

 	if (fragid == LAST_FRAGMENT) {
 		TIPC_SKB_CB(head)->validated = false;
 		if (unlikely(!tipc_msg_validate(head)))
 			goto err;
 		*buf = head;
 		TIPC_SKB_CB(head)->tail = NULL;
 		*headbuf = NULL;
 		return 1;
 	}
 	*buf = NULL;
 	return 0;
 err:
 	kfree_skb(*buf);
 	kfree_skb(*headbuf);
 	*buf = *headbuf = NULL;
 	return 0;
 }

 /* tipc_msg_validate - validate basic format of received message
  *
  * This routine ensures a TIPC message has an acceptable header, and at least
  * as much data as the header indicates it should.  The routine also ensures
  * that the entire message header is stored in the main fragment of the message
  * buffer, to simplify future access to message header fields.
  *
  * Note: Having extra info present in the message header or data areas is OK.
  * TIPC will ignore the excess, under the assumption that it is optional info
  * introduced by a later release of the protocol.
  */
 bool tipc_msg_validate(struct sk_buff *skb)
 {
 	struct tipc_msg *msg;
 	int msz, hsz;

 	if (unlikely(TIPC_SKB_CB(skb)->validated))
 		return true;
 	if (unlikely(!pskb_may_pull(skb, MIN_H_SIZE)))
 		return false;

 	hsz = msg_hdr_sz(buf_msg(skb));
 	if (unlikely(hsz < MIN_H_SIZE) || (hsz > MAX_H_SIZE))
 		return false;
 	if (unlikely(!pskb_may_pull(skb, hsz)))
 		return false;

 	msg = buf_msg(skb);
 	if (unlikely(msg_version(msg) != TIPC_VERSION))
 		return false;

 	msz = msg_size(msg);
 	if (unlikely(msz < hsz))
 		return false;
 	if (unlikely((msz - hsz) > TIPC_MAX_USER_MSG_SIZE))
 		return false;
 	if (unlikely(skb->len < msz))
 		return false;

 	TIPC_SKB_CB(skb)->validated = true;
 	return true;
 }

 /**
  * tipc_msg_build - create buffer chain containing specified header and data
  * @mhdr: Message header, to be prepended to data
  * @m: User message
  * @dsz: Total length of user data
  * @pktmax: Max packet size that can be used
  * @list: Buffer or chain of buffers to be returned to caller
  *
  * Returns message data size or errno: -ENOMEM, -EFAULT
  */
 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m,
 		   int offset, int dsz, int pktmax, struct sk_buff_head *list)
 {
 	int mhsz = msg_hdr_sz(mhdr);
 	int msz = mhsz + dsz;
 	int pktno = 1;
 	int pktsz;
 	int pktrem = pktmax;
 	int drem = dsz;
 	struct tipc_msg pkthdr;
 	struct sk_buff *skb;
 	char *pktpos;
 	int rc;

 	msg_set_size(mhdr, msz);

 	/* No fragmentation needed? */
 	if (likely(msz <= pktmax)) {
 		skb = tipc_buf_acquire(msz);
 		if (unlikely(!skb))
 			return -ENOMEM;
 		skb_orphan(skb);
 		__skb_queue_tail(list, skb);
 		skb_copy_to_linear_data(skb, mhdr, mhsz);
 		pktpos = skb->data + mhsz;
 		if (copy_from_iter(pktpos, dsz, &m->msg_iter) == dsz)
 			return dsz;
 		rc = -EFAULT;
 		goto error;
 	}

 	/* Prepare reusable fragment header */
 	tipc_msg_init(msg_prevnode(mhdr), &pkthdr, MSG_FRAGMENTER,
 		      FIRST_FRAGMENT, INT_H_SIZE, msg_destnode(mhdr));
 	msg_set_size(&pkthdr, pktmax);
 	msg_set_fragm_no(&pkthdr, pktno);
 	msg_set_importance(&pkthdr, msg_importance(mhdr));

 	/* Prepare first fragment */
 	skb = tipc_buf_acquire(pktmax);
 	if (!skb)
 		return -ENOMEM;
 	skb_orphan(skb);
 	__skb_queue_tail(list, skb);
 	pktpos = skb->data;
 	skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
 	pktpos += INT_H_SIZE;
 	pktrem -= INT_H_SIZE;
 	skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
 	pktpos += mhsz;
 	pktrem -= mhsz;

 	do {
 		if (drem < pktrem)
 			pktrem = drem;

 		if (copy_from_iter(pktpos, pktrem, &m->msg_iter) != pktrem) {
 			rc = -EFAULT;
 			goto error;
 		}
 		drem -= pktrem;

 		if (!drem)
 			break;

 		/* Prepare new fragment: */
 		if (drem < (pktmax - INT_H_SIZE))
 			pktsz = drem + INT_H_SIZE;
 		else
 			pktsz = pktmax;
 		skb = tipc_buf_acquire(pktsz);
 		if (!skb) {
 			rc = -ENOMEM;
 			goto error;
 		}
 		skb_orphan(skb);
 		__skb_queue_tail(list, skb);
 		msg_set_type(&pkthdr, FRAGMENT);
 		msg_set_size(&pkthdr, pktsz);
 		msg_set_fragm_no(&pkthdr, ++pktno);
 		skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
 		pktpos = skb->data + INT_H_SIZE;
 		pktrem = pktsz - INT_H_SIZE;

 	} while (1);
 	msg_set_type(buf_msg(skb), LAST_FRAGMENT);
 	return dsz;
 error:
 	__skb_queue_purge(list);
 	__skb_queue_head_init(list);
 	return rc;
 }

 /**
  * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
  * @skb: the buffer to append to ("bundle")
  * @msg:  message to be appended
  * @mtu:  max allowable size for the bundle buffer
  * Consumes buffer if successful
  * Returns true if bundling could be performed, otherwise false
  */
 bool tipc_msg_bundle(struct sk_buff *skb, struct tipc_msg *msg, u32 mtu)
 {
 	struct tipc_msg *bmsg;
 	unsigned int bsz;
 	unsigned int msz = msg_size(msg);
 	u32 start, pad;
 	u32 max = mtu - INT_H_SIZE;

 	if (likely(msg_user(msg) == MSG_FRAGMENTER))
 		return false;
 	if (!skb)
 		return false;
 	bmsg = buf_msg(skb);
 	bsz = msg_size(bmsg);
 	start = align(bsz);
 	pad = start - bsz;

 	if (unlikely(msg_user(msg) == TUNNEL_PROTOCOL))
 		return false;
 	if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
 		return false;
 	if (unlikely(msg_user(bmsg) != MSG_BUNDLER))
 		return false;
 	if (unlikely(skb_tailroom(skb) < (pad + msz)))
 		return false;
 	if (unlikely(max < (start + msz)))
 		return false;
 	if ((msg_importance(msg) < TIPC_SYSTEM_IMPORTANCE) &&
 	    (msg_importance(bmsg) == TIPC_SYSTEM_IMPORTANCE))
 		return false;

 	skb_put(skb, pad + msz);
 	skb_copy_to_linear_data_offset(skb, start, msg, msz);
 	msg_set_size(bmsg, start + msz);
 	msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
 	return true;
 }

 /**
  *  tipc_msg_extract(): extract bundled inner packet from buffer
  *  @skb: buffer to be extracted from.
  *  @iskb: extracted inner buffer, to be returned
  *  @pos: position in outer message of msg to be extracted.
  *        Returns position of next msg
  *  Consumes outer buffer when last packet extracted
  *  Returns true when when there is an extracted buffer, otherwise false
  */
 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
 {
 	struct tipc_msg *msg;
 	int imsz, offset;

 	*iskb = NULL;
 	if (unlikely(skb_linearize(skb)))
 		goto none;

 	msg = buf_msg(skb);
 	offset = msg_hdr_sz(msg) + *pos;
 	if (unlikely(offset > (msg_size(msg) - MIN_H_SIZE)))
 		goto none;

 	*iskb = skb_clone(skb, GFP_ATOMIC);
 	if (unlikely(!*iskb))
 		goto none;
 	skb_pull(*iskb, offset);
 	imsz = msg_size(buf_msg(*iskb));
 	skb_trim(*iskb, imsz);
 	if (unlikely(!tipc_msg_validate(*iskb)))
 		goto none;
 	*pos += align(imsz);
 	return true;
 none:
 	kfree_skb(skb);
 	kfree_skb(*iskb);
 	*iskb = NULL;
 	return false;
 }

 /**
  * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
  * @list: the buffer chain, where head is the buffer to replace/append
  * @skb: buffer to be created, appended to and returned in case of success
  * @msg: message to be appended
  * @mtu: max allowable size for the bundle buffer, inclusive header
  * @dnode: destination node for message. (Not always present in header)
  * Returns true if success, otherwise false
  */
 bool tipc_msg_make_bundle(struct sk_buff **skb,  struct tipc_msg *msg,
 			  u32 mtu, u32 dnode)
 {
 	struct sk_buff *_skb;
 	struct tipc_msg *bmsg;
 	u32 msz = msg_size(msg);
 	u32 max = mtu - INT_H_SIZE;

 	if (msg_user(msg) == MSG_FRAGMENTER)
 		return false;
 	if (msg_user(msg) == TUNNEL_PROTOCOL)
 		return false;
 	if (msg_user(msg) == BCAST_PROTOCOL)
 		return false;
 	if (msz > (max / 2))
 		return false;

 	_skb = tipc_buf_acquire(max);
 	if (!_skb)
 		return false;

 	skb_trim(_skb, INT_H_SIZE);
 	bmsg = buf_msg(_skb);
 	tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
 		      INT_H_SIZE, dnode);
 	if (msg_isdata(msg))
 		msg_set_importance(bmsg, TIPC_CRITICAL_IMPORTANCE);
 	else
 		msg_set_importance(bmsg, TIPC_SYSTEM_IMPORTANCE);
 	msg_set_seqno(bmsg, msg_seqno(msg));
 	msg_set_ack(bmsg, msg_ack(msg));
 	msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
 	tipc_msg_bundle(_skb, msg, mtu);
 	*skb = _skb;
 	return true;
 }

 /**
  * tipc_msg_reverse(): swap source and destination addresses and add error code
  * @own_node: originating node id for reversed message
  * @skb:  buffer containing message to be reversed; may be replaced.
  * @err:  error code to be set in message, if any
  * Consumes buffer at failure
  * Returns true if success, otherwise false
  */
 bool tipc_msg_reverse(u32 own_node,  struct sk_buff **skb, int err)
 {
 	struct sk_buff *_skb = *skb;
 	struct tipc_msg *hdr = buf_msg(_skb);
 	struct tipc_msg ohdr;
 	int dlen = min_t(uint, msg_data_sz(hdr), MAX_FORWARD_SIZE);

 	if (skb_linearize(_skb))
 		goto exit;
 	hdr = buf_msg(_skb);
 	if (msg_dest_droppable(hdr))
 		goto exit;
 	if (msg_errcode(hdr))
 		goto exit;

 	/* Take a copy of original header before altering message */
 	memcpy(&ohdr, hdr, msg_hdr_sz(hdr));

 	/* Never return SHORT header; expand by replacing buffer if necessary */
 	if (msg_short(hdr)) {
 		*skb = tipc_buf_acquire(BASIC_H_SIZE + dlen);
 		if (!*skb)
 			goto exit;
 		memcpy((*skb)->data + BASIC_H_SIZE, msg_data(hdr), dlen);
 		kfree_skb(_skb);
 		_skb = *skb;
 		hdr = buf_msg(_skb);
 		memcpy(hdr, &ohdr, BASIC_H_SIZE);
 		msg_set_hdr_sz(hdr, BASIC_H_SIZE);
 	}

 	/* Now reverse the concerned fields */
 	msg_set_errcode(hdr, err);
 	msg_set_origport(hdr, msg_destport(&ohdr));
 	msg_set_destport(hdr, msg_origport(&ohdr));
 	msg_set_destnode(hdr, msg_prevnode(&ohdr));
 	msg_set_prevnode(hdr, own_node);
 	msg_set_orignode(hdr, own_node);
 	msg_set_size(hdr, msg_hdr_sz(hdr) + dlen);
 	skb_trim(_skb, msg_size(hdr));
 	skb_orphan(_skb);
 	return true;
 exit:
 	kfree_skb(_skb);
 	*skb = NULL;
 	return false;
 }

 /**
  * tipc_msg_lookup_dest(): try to find new destination for named message
  * @skb: the buffer containing the message.
  * @err: error code to be used by caller if lookup fails
  * Does not consume buffer
  * Returns true if a destination is found, false otherwise
  */
 bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, int *err)
 {
 	struct tipc_msg *msg = buf_msg(skb);
 	u32 dport, dnode;
 	u32 onode = tipc_own_addr(net);

 	if (!msg_isdata(msg))
 		return false;
 	if (!msg_named(msg))
 		return false;
 	if (msg_errcode(msg))
 		return false;
 	*err = TIPC_ERR_NO_NAME;
 	if (skb_linearize(skb))
 		return false;
 	msg = buf_msg(skb);
 	if (msg_reroute_cnt(msg))
 		return false;
 	dnode = addr_domain(net, msg_lookup_scope(msg));
 	dport = tipc_nametbl_translate(net, msg_nametype(msg),
 				       msg_nameinst(msg), &dnode);
 	if (!dport)
 		return false;
 	msg_incr_reroute_cnt(msg);
 	if (dnode != onode)
 		msg_set_prevnode(msg, onode);
 	msg_set_destnode(msg, dnode);
 	msg_set_destport(msg, dport);
 	*err = TIPC_OK;
 	return true;
 }

 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
  *                         reassemble the clones into one message
  */
 bool tipc_msg_reassemble(struct sk_buff_head *list, struct sk_buff_head *rcvq)
 {
 	struct sk_buff *skb, *_skb;
 	struct sk_buff *frag = NULL;
 	struct sk_buff *head = NULL;
 	int hdr_len;

 	/* Copy header if single buffer */
 	if (skb_queue_len(list) == 1) {
 		skb = skb_peek(list);
 		hdr_len = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
 		_skb = __pskb_copy(skb, hdr_len, GFP_ATOMIC);
 		if (!_skb)
 			return false;
 		__skb_queue_tail(rcvq, _skb);
 		return true;
 	}

 	/* Clone all fragments and reassemble */
 	skb_queue_walk(list, skb) {
 		frag = skb_clone(skb, GFP_ATOMIC);
 		if (!frag)
 			goto error;
 		frag->next = NULL;
 		if (tipc_buf_append(&head, &frag))
 			break;
 		if (!head)
 			goto error;
 	}
 	__skb_queue_tail(rcvq, frag);
 	return true;
 error:
 	pr_warn("Failed do clone local mcast rcv buffer\n");
 	kfree_skb(head);
 	return false;
 }

 /* tipc_skb_queue_sorted(); sort pkt into list according to sequence number
  * @list: list to be appended to
  * @seqno: sequence number of buffer to add
  * @skb: buffer to add
  */
 void __tipc_skb_queue_sorted(struct sk_buff_head *list, u16 seqno,
 			     struct sk_buff *skb)
 {
 	struct sk_buff *_skb, *tmp;

 	if (skb_queue_empty(list) || less(seqno, buf_seqno(skb_peek(list)))) {
 		__skb_queue_head(list, skb);
 		return;
 	}

 	if (more(seqno, buf_seqno(skb_peek_tail(list)))) {
 		__skb_queue_tail(list, skb);
 		return;
 	}

 	skb_queue_walk_safe(list, _skb, tmp) {
 		if (more(seqno, buf_seqno(_skb)))
 			continue;
 		if (seqno == buf_seqno(_skb))
 			break;
 		__skb_queue_before(list, _skb, skb);
 		return;
 	}
 	kfree_skb(skb);
 }
	/*
	* net/tipc/msg.c: TIPC message header routines
	*
	* Copyright (c) 2000-2006, 2014-2015, Ericsson AB
	* Copyright (c) 2005, 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.
	*/

	#include <net/sock.h>
	#include "core.h"
	#include "msg.h"
	#include "addr.h"
	#include "name_table.h"

	#define MAX_FORWARD_SIZE 1024

	static unsigned int align(unsigned int i)
	{
	return (i + 3) & ~3u;
	}

	/**
	* tipc_buf_acquire - creates a TIPC message buffer
	* @size: message size (including TIPC header)
	*
	* Returns a new buffer with data pointers set to the specified size.
	*
	* NOTE: Headroom is reserved to allow prepending of a data link header.
	* There may also be unrequested tailroom present at the buffer's end.
	*/
	struct sk_buff *tipc_buf_acquire(u32 size)
	{
	struct sk_buff *skb;
	unsigned int buf_size = (BUF_HEADROOM + size + 3) & ~3u;

	skb = alloc_skb_fclone(buf_size, GFP_ATOMIC);
	if (skb) {
	skb_reserve(skb, BUF_HEADROOM);
	skb_put(skb, size);
	skb->next = NULL;
	}
	return skb;
	}

	void tipc_msg_init(u32 own_node, struct tipc_msg *m, u32 user, u32 type,
	u32 hsize, u32 dnode)
	{
	memset(m, 0, hsize);
	msg_set_version(m);
	msg_set_user(m, user);
	msg_set_hdr_sz(m, hsize);
	msg_set_size(m, hsize);
	msg_set_prevnode(m, own_node);
	msg_set_type(m, type);
	if (hsize > SHORT_H_SIZE) {
	msg_set_orignode(m, own_node);
	msg_set_destnode(m, dnode);
	}
	}

	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)
	{
	struct tipc_msg *msg;
	struct sk_buff *buf;

	buf = tipc_buf_acquire(hdr_sz + data_sz);
	if (unlikely(!buf))
	return NULL;

	msg = buf_msg(buf);
	tipc_msg_init(onode, msg, user, type, hdr_sz, dnode);
	msg_set_size(msg, hdr_sz + data_sz);
	msg_set_origport(msg, oport);
	msg_set_destport(msg, dport);
	msg_set_errcode(msg, errcode);
	if (hdr_sz > SHORT_H_SIZE) {
	msg_set_orignode(msg, onode);
	msg_set_destnode(msg, dnode);
	}
	return buf;
	}

	/* tipc_buf_append(): Append a buffer to the fragment list of another buffer
	* @*headbuf: in: NULL for first frag, otherwise value returned from prev call
	* out: set when successful non-complete reassembly, otherwise NULL
	* @*buf: in: the buffer to append. Always defined
	* out: head buf after successful complete reassembly, otherwise NULL
	* Returns 1 when reassembly complete, otherwise 0
	*/
	int tipc_buf_append(struct sk_buff headbuf, struct sk_buff buf)
	{
	struct sk_buff head = headbuf;
	struct sk_buff frag = buf;
	struct sk_buff *tail = NULL;
	struct tipc_msg *msg;
	u32 fragid;
	int delta;
	bool headstolen;

	if (!frag)
	goto err;

	msg = buf_msg(frag);
	fragid = msg_type(msg);
	frag->next = NULL;
	skb_pull(frag, msg_hdr_sz(msg));

	if (fragid == FIRST_FRAGMENT) {
	if (unlikely(head))
	goto err;
	if (unlikely(skb_unclone(frag, GFP_ATOMIC)))
	goto err;
	head = *headbuf = frag;
	*buf = NULL;
	TIPC_SKB_CB(head)->tail = NULL;
	if (skb_is_nonlinear(head)) {
	skb_walk_frags(head, tail) {
	TIPC_SKB_CB(head)->tail = tail;
	}
	} else {
	skb_frag_list_init(head);
	}
	return 0;
	}

	if (!head)
	goto err;

	if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
	kfree_skb_partial(frag, headstolen);
	} else {
	tail = TIPC_SKB_CB(head)->tail;
	if (!skb_has_frag_list(head))
	skb_shinfo(head)->frag_list = frag;
	else
	tail->next = frag;
	head->truesize += frag->truesize;
	head->data_len += frag->len;
	head->len += frag->len;
	TIPC_SKB_CB(head)->tail = frag;
	}

	if (fragid == LAST_FRAGMENT) {
	TIPC_SKB_CB(head)->validated = false;
	if (unlikely(!tipc_msg_validate(head)))
	goto err;
	*buf = head;
	TIPC_SKB_CB(head)->tail = NULL;
	*headbuf = NULL;
	return 1;
	}
	*buf = NULL;
	return 0;
	err:
	kfree_skb(*buf);
	kfree_skb(*headbuf);
	buf = headbuf = NULL;
	return 0;
	}

	/* tipc_msg_validate - validate basic format of received message
	*
	* This routine ensures a TIPC message has an acceptable header, and at least
	* as much data as the header indicates it should. The routine also ensures
	* that the entire message header is stored in the main fragment of the message
	* buffer, to simplify future access to message header fields.
	*
	* Note: Having extra info present in the message header or data areas is OK.
	* TIPC will ignore the excess, under the assumption that it is optional info
	* introduced by a later release of the protocol.
	*/
	bool tipc_msg_validate(struct sk_buff *skb)
	{
	struct tipc_msg *msg;
	int msz, hsz;

	if (unlikely(TIPC_SKB_CB(skb)->validated))
	return true;
	if (unlikely(!pskb_may_pull(skb, MIN_H_SIZE)))
	return false;

	hsz = msg_hdr_sz(buf_msg(skb));
	if (unlikely(hsz < MIN_H_SIZE) \|\| (hsz > MAX_H_SIZE))
	return false;
	if (unlikely(!pskb_may_pull(skb, hsz)))
	return false;

	msg = buf_msg(skb);
	if (unlikely(msg_version(msg) != TIPC_VERSION))
	return false;

	msz = msg_size(msg);
	if (unlikely(msz < hsz))
	return false;
	if (unlikely((msz - hsz) > TIPC_MAX_USER_MSG_SIZE))
	return false;
	if (unlikely(skb->len < msz))
	return false;

	TIPC_SKB_CB(skb)->validated = true;
	return true;
	}

	/**
	* tipc_msg_build - create buffer chain containing specified header and data
	* @mhdr: Message header, to be prepended to data
	* @m: User message
	* @dsz: Total length of user data
	* @pktmax: Max packet size that can be used
	* @list: Buffer or chain of buffers to be returned to caller
	*
	* Returns message data size or errno: -ENOMEM, -EFAULT
	*/
	int tipc_msg_build(struct tipc_msg mhdr, struct msghdr m,
	int offset, int dsz, int pktmax, struct sk_buff_head *list)
	{
	int mhsz = msg_hdr_sz(mhdr);
	int msz = mhsz + dsz;
	int pktno = 1;
	int pktsz;
	int pktrem = pktmax;
	int drem = dsz;
	struct tipc_msg pkthdr;
	struct sk_buff *skb;
	char *pktpos;
	int rc;

	msg_set_size(mhdr, msz);

	/* No fragmentation needed? */
	if (likely(msz <= pktmax)) {
	skb = tipc_buf_acquire(msz);
	if (unlikely(!skb))
	return -ENOMEM;
	skb_orphan(skb);
	__skb_queue_tail(list, skb);
	skb_copy_to_linear_data(skb, mhdr, mhsz);
	pktpos = skb->data + mhsz;
	if (copy_from_iter(pktpos, dsz, &m->msg_iter) == dsz)
	return dsz;
	rc = -EFAULT;
	goto error;
	}

	/* Prepare reusable fragment header */
	tipc_msg_init(msg_prevnode(mhdr), &pkthdr, MSG_FRAGMENTER,
	FIRST_FRAGMENT, INT_H_SIZE, msg_destnode(mhdr));
	msg_set_size(&pkthdr, pktmax);
	msg_set_fragm_no(&pkthdr, pktno);
	msg_set_importance(&pkthdr, msg_importance(mhdr));

	/* Prepare first fragment */
	skb = tipc_buf_acquire(pktmax);
	if (!skb)
	return -ENOMEM;
	skb_orphan(skb);
	__skb_queue_tail(list, skb);
	pktpos = skb->data;
	skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
	pktpos += INT_H_SIZE;
	pktrem -= INT_H_SIZE;
	skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
	pktpos += mhsz;
	pktrem -= mhsz;

	do {
	if (drem < pktrem)
	pktrem = drem;

	if (copy_from_iter(pktpos, pktrem, &m->msg_iter) != pktrem) {
	rc = -EFAULT;
	goto error;
	}
	drem -= pktrem;

	if (!drem)
	break;

	/* Prepare new fragment: */
	if (drem < (pktmax - INT_H_SIZE))
	pktsz = drem + INT_H_SIZE;
	else
	pktsz = pktmax;
	skb = tipc_buf_acquire(pktsz);
	if (!skb) {
	rc = -ENOMEM;
	goto error;
	}
	skb_orphan(skb);
	__skb_queue_tail(list, skb);
	msg_set_type(&pkthdr, FRAGMENT);
	msg_set_size(&pkthdr, pktsz);
	msg_set_fragm_no(&pkthdr, ++pktno);
	skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
	pktpos = skb->data + INT_H_SIZE;
	pktrem = pktsz - INT_H_SIZE;

	} while (1);
	msg_set_type(buf_msg(skb), LAST_FRAGMENT);
	return dsz;
	error:
	__skb_queue_purge(list);
	__skb_queue_head_init(list);
	return rc;
	}

	/**
	* tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
	* @skb: the buffer to append to ("bundle")
	* @msg: message to be appended
	* @mtu: max allowable size for the bundle buffer
	* Consumes buffer if successful
	* Returns true if bundling could be performed, otherwise false
	*/
	bool tipc_msg_bundle(struct sk_buff skb, struct tipc_msg msg, u32 mtu)
	{
	struct tipc_msg *bmsg;
	unsigned int bsz;
	unsigned int msz = msg_size(msg);
	u32 start, pad;
	u32 max = mtu - INT_H_SIZE;

	if (likely(msg_user(msg) == MSG_FRAGMENTER))
	return false;
	if (!skb)
	return false;
	bmsg = buf_msg(skb);
	bsz = msg_size(bmsg);
	start = align(bsz);
	pad = start - bsz;

	if (unlikely(msg_user(msg) == TUNNEL_PROTOCOL))
	return false;
	if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
	return false;
	if (unlikely(msg_user(bmsg) != MSG_BUNDLER))
	return false;
	if (unlikely(skb_tailroom(skb) < (pad + msz)))
	return false;
	if (unlikely(max < (start + msz)))
	return false;
	if ((msg_importance(msg) < TIPC_SYSTEM_IMPORTANCE) &&
	(msg_importance(bmsg) == TIPC_SYSTEM_IMPORTANCE))
	return false;

	skb_put(skb, pad + msz);
	skb_copy_to_linear_data_offset(skb, start, msg, msz);
	msg_set_size(bmsg, start + msz);
	msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
	return true;
	}

	/**
	* tipc_msg_extract(): extract bundled inner packet from buffer
	* @skb: buffer to be extracted from.
	* @iskb: extracted inner buffer, to be returned
	* @pos: position in outer message of msg to be extracted.
	* Returns position of next msg
	* Consumes outer buffer when last packet extracted
	* Returns true when when there is an extracted buffer, otherwise false
	*/
	bool tipc_msg_extract(struct sk_buff skb, struct sk_buff iskb, int pos)
	{
	struct tipc_msg *msg;
	int imsz, offset;

	*iskb = NULL;
	if (unlikely(skb_linearize(skb)))
	goto none;

	msg = buf_msg(skb);
	offset = msg_hdr_sz(msg) + *pos;
	if (unlikely(offset > (msg_size(msg) - MIN_H_SIZE)))
	goto none;

	*iskb = skb_clone(skb, GFP_ATOMIC);
	if (unlikely(!*iskb))
	goto none;
	skb_pull(*iskb, offset);
	imsz = msg_size(buf_msg(*iskb));
	skb_trim(*iskb, imsz);
	if (unlikely(!tipc_msg_validate(*iskb)))
	goto none;
	*pos += align(imsz);
	return true;
	none:
	kfree_skb(skb);
	kfree_skb(*iskb);
	*iskb = NULL;
	return false;
	}

	/**
	* tipc_msg_make_bundle(): Create bundle buf and append message to its tail
	* @list: the buffer chain, where head is the buffer to replace/append
	* @skb: buffer to be created, appended to and returned in case of success
	* @msg: message to be appended
	* @mtu: max allowable size for the bundle buffer, inclusive header
	* @dnode: destination node for message. (Not always present in header)
	* Returns true if success, otherwise false
	*/
	bool tipc_msg_make_bundle(struct sk_buff *skb, struct tipc_msg msg,
	u32 mtu, u32 dnode)
	{
	struct sk_buff *_skb;
	struct tipc_msg *bmsg;
	u32 msz = msg_size(msg);
	u32 max = mtu - INT_H_SIZE;

	if (msg_user(msg) == MSG_FRAGMENTER)
	return false;
	if (msg_user(msg) == TUNNEL_PROTOCOL)
	return false;
	if (msg_user(msg) == BCAST_PROTOCOL)
	return false;
	if (msz > (max / 2))
	return false;

	_skb = tipc_buf_acquire(max);
	if (!_skb)
	return false;

	skb_trim(_skb, INT_H_SIZE);
	bmsg = buf_msg(_skb);
	tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
	INT_H_SIZE, dnode);
	if (msg_isdata(msg))
	msg_set_importance(bmsg, TIPC_CRITICAL_IMPORTANCE);
	else
	msg_set_importance(bmsg, TIPC_SYSTEM_IMPORTANCE);
	msg_set_seqno(bmsg, msg_seqno(msg));
	msg_set_ack(bmsg, msg_ack(msg));
	msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
	tipc_msg_bundle(_skb, msg, mtu);
	*skb = _skb;
	return true;
	}

	/**
	* tipc_msg_reverse(): swap source and destination addresses and add error code
	* @own_node: originating node id for reversed message
	* @skb: buffer containing message to be reversed; may be replaced.
	* @err: error code to be set in message, if any
	* Consumes buffer at failure
	* Returns true if success, otherwise false
	*/
	bool tipc_msg_reverse(u32 own_node, struct sk_buff **skb, int err)
	{
	struct sk_buff _skb = skb;
	struct tipc_msg *hdr = buf_msg(_skb);
	struct tipc_msg ohdr;
	int dlen = min_t(uint, msg_data_sz(hdr), MAX_FORWARD_SIZE);

	if (skb_linearize(_skb))
	goto exit;
	hdr = buf_msg(_skb);
	if (msg_dest_droppable(hdr))
	goto exit;
	if (msg_errcode(hdr))
	goto exit;

	/* Take a copy of original header before altering message */
	memcpy(&ohdr, hdr, msg_hdr_sz(hdr));

	/* Never return SHORT header; expand by replacing buffer if necessary */
	if (msg_short(hdr)) {
	*skb = tipc_buf_acquire(BASIC_H_SIZE + dlen);
	if (!*skb)
	goto exit;
	memcpy((*skb)->data + BASIC_H_SIZE, msg_data(hdr), dlen);
	kfree_skb(_skb);
	_skb = *skb;
	hdr = buf_msg(_skb);
	memcpy(hdr, &ohdr, BASIC_H_SIZE);
	msg_set_hdr_sz(hdr, BASIC_H_SIZE);
	}

	/* Now reverse the concerned fields */
	msg_set_errcode(hdr, err);
	msg_set_origport(hdr, msg_destport(&ohdr));
	msg_set_destport(hdr, msg_origport(&ohdr));
	msg_set_destnode(hdr, msg_prevnode(&ohdr));
	msg_set_prevnode(hdr, own_node);
	msg_set_orignode(hdr, own_node);
	msg_set_size(hdr, msg_hdr_sz(hdr) + dlen);
	skb_trim(_skb, msg_size(hdr));
	skb_orphan(_skb);
	return true;
	exit:
	kfree_skb(_skb);
	*skb = NULL;
	return false;
	}

	/**
	* tipc_msg_lookup_dest(): try to find new destination for named message
	* @skb: the buffer containing the message.
	* @err: error code to be used by caller if lookup fails
	* Does not consume buffer
	* Returns true if a destination is found, false otherwise
	*/
	bool tipc_msg_lookup_dest(struct net net, struct sk_buff skb, int *err)
	{
	struct tipc_msg *msg = buf_msg(skb);
	u32 dport, dnode;
	u32 onode = tipc_own_addr(net);

	if (!msg_isdata(msg))
	return false;
	if (!msg_named(msg))
	return false;
	if (msg_errcode(msg))
	return false;
	*err = TIPC_ERR_NO_NAME;
	if (skb_linearize(skb))
	return false;
	msg = buf_msg(skb);
	if (msg_reroute_cnt(msg))
	return false;
	dnode = addr_domain(net, msg_lookup_scope(msg));
	dport = tipc_nametbl_translate(net, msg_nametype(msg),
	msg_nameinst(msg), &dnode);
	if (!dport)
	return false;
	msg_incr_reroute_cnt(msg);
	if (dnode != onode)
	msg_set_prevnode(msg, onode);
	msg_set_destnode(msg, dnode);
	msg_set_destport(msg, dport);
	*err = TIPC_OK;
	return true;
	}

	/* tipc_msg_reassemble() - clone a buffer chain of fragments and
	* reassemble the clones into one message
	*/
	bool tipc_msg_reassemble(struct sk_buff_head list, struct sk_buff_head rcvq)
	{
	struct sk_buff skb, _skb;
	struct sk_buff *frag = NULL;
	struct sk_buff *head = NULL;
	int hdr_len;

	/* Copy header if single buffer */
	if (skb_queue_len(list) == 1) {
	skb = skb_peek(list);
	hdr_len = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
	_skb = __pskb_copy(skb, hdr_len, GFP_ATOMIC);
	if (!_skb)
	return false;
	__skb_queue_tail(rcvq, _skb);
	return true;
	}

	/* Clone all fragments and reassemble */
	skb_queue_walk(list, skb) {
	frag = skb_clone(skb, GFP_ATOMIC);
	if (!frag)
	goto error;
	frag->next = NULL;
	if (tipc_buf_append(&head, &frag))
	break;
	if (!head)
	goto error;
	}
	__skb_queue_tail(rcvq, frag);
	return true;
	error:
	pr_warn("Failed do clone local mcast rcv buffer\n");
	kfree_skb(head);
	return false;
	}

	/* tipc_skb_queue_sorted(); sort pkt into list according to sequence number
	* @list: list to be appended to
	* @seqno: sequence number of buffer to add
	* @skb: buffer to add
	*/
	void __tipc_skb_queue_sorted(struct sk_buff_head *list, u16 seqno,
	struct sk_buff *skb)
	{
	struct sk_buff _skb, tmp;

	if (skb_queue_empty(list) \|\| less(seqno, buf_seqno(skb_peek(list)))) {
	__skb_queue_head(list, skb);
	return;
	}

	if (more(seqno, buf_seqno(skb_peek_tail(list)))) {
	__skb_queue_tail(list, skb);
	return;
	}

	skb_queue_walk_safe(list, _skb, tmp) {
	if (more(seqno, buf_seqno(_skb)))
	continue;
	if (seqno == buf_seqno(_skb))
	break;
	__skb_queue_before(list, _skb, skb);
	return;
	}
	kfree_skb(skb);
	}