/* * net/tipc/msg.c: TIPC message header routines * * Copyright (c) 2000-2006, 2014, 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;	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;		skb_frag_list_init(head);		TIPC_SKB_CB(head)->tail = NULL;		*buf = NULL;		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) {		*buf = head;		TIPC_SKB_CB(head)->tail = NULL;		*headbuf = NULL;		return 1;	}	*buf = NULL;	return 0; err:	pr_warn_ratelimited("Unable to build fragment list\n");	kfree_skb(*buf);	kfree_skb(*headbuf);	*buf = *headbuf = NULL;	return 0;}  /** * 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); 	/* 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 * @list: the buffer chain of the existing buffer ("bundle") * @skb:  buffer 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_head *list, struct sk_buff *skb, u32 mtu){	struct sk_buff *bskb = skb_peek_tail(list);	struct tipc_msg *bmsg = buf_msg(bskb);	struct tipc_msg *msg = buf_msg(skb);	unsigned int bsz = msg_size(bmsg);	unsigned int msz = msg_size(msg);	u32 start = align(bsz);	u32 max = mtu - INT_H_SIZE;	u32 pad = start - bsz; 	if (likely(msg_user(msg) == MSG_FRAGMENTER))		return false;	if (unlikely(msg_user(msg) == CHANGEOVER_PROTOCOL))		return false;	if (unlikely(msg_user(msg) == BCAST_PROTOCOL))		return false;	if (likely(msg_user(bmsg) != MSG_BUNDLER))		return false;	if (likely(!TIPC_SKB_CB(bskb)->bundling))		return false;	if (unlikely(skb_tailroom(bskb) < (pad + msz)))		return false;	if (unlikely(max < (start + msz)))		return false; 	skb_put(bskb, pad + msz);	skb_copy_to_linear_data_offset(bskb, start, skb->data, msz);	msg_set_size(bmsg, start + msz);	msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);	kfree_skb(skb);	return true;} /** *  tipc_msg_extract(): extract bundled inner packet from buffer *  @skb: linear outer buffer, to be extracted from. *  @iskb: extracted inner buffer, to be returned *  @pos: position of msg to be extracted. Returns with pointer 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 = buf_msg(skb);	int imsz;	struct tipc_msg *imsg = (struct tipc_msg *)(msg_data(msg) + *pos); 	/* Is there space left for shortest possible message? */	if (*pos > (msg_data_sz(msg) - SHORT_H_SIZE))		goto none;	imsz = msg_size(imsg); 	/* Is there space left for current message ? */	if ((*pos + imsz) > msg_data_sz(msg))		goto none;	*iskb = tipc_buf_acquire(imsz);	if (!*iskb)		goto none;	skb_copy_to_linear_data(*iskb, imsg, imsz);	*pos += align(imsz);	return true;none:	kfree_skb(skb);	*iskb = NULL;	return false;} /** * tipc_msg_make_bundle(): Create bundle buf and append message to its tail * @list: the buffer chain * @skb: buffer to be appended and replaced * @mtu: max allowable size for the bundle buffer, inclusive header * @dnode: destination node for message. (Not always present in header) * Replaces buffer if successful * Returns true if success, otherwise false */bool tipc_msg_make_bundle(struct sk_buff_head *list,			  struct sk_buff *skb, u32 mtu, u32 dnode){	struct sk_buff *bskb;	struct tipc_msg *bmsg;	struct tipc_msg *msg = buf_msg(skb);	u32 msz = msg_size(msg);	u32 max = mtu - INT_H_SIZE; 	if (msg_user(msg) == MSG_FRAGMENTER)		return false;	if (msg_user(msg) == CHANGEOVER_PROTOCOL)		return false;	if (msg_user(msg) == BCAST_PROTOCOL)		return false;	if (msz > (max / 2))		return false; 	bskb = tipc_buf_acquire(max);	if (!bskb)		return false; 	skb_trim(bskb, INT_H_SIZE);	bmsg = buf_msg(bskb);	tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,		      INT_H_SIZE, dnode);	msg_set_seqno(bmsg, msg_seqno(msg));	msg_set_ack(bmsg, msg_ack(msg));	msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));	TIPC_SKB_CB(bskb)->bundling = true;	__skb_queue_tail(list, bskb);	return tipc_msg_bundle(list, skb, mtu);} /** * tipc_msg_reverse(): swap source and destination addresses and add error code * @buf:  buffer containing message to be reversed * @dnode: return value: node where to send message after reversal * @err:  error code to be set in message * Consumes buffer if failure * Returns true if success, otherwise false */bool tipc_msg_reverse(u32 own_addr,  struct sk_buff *buf, u32 *dnode,		      int err){	struct tipc_msg *msg = buf_msg(buf);	uint imp = msg_importance(msg);	struct tipc_msg ohdr;	uint rdsz = min_t(uint, msg_data_sz(msg), MAX_FORWARD_SIZE); 	if (skb_linearize(buf))		goto exit;	if (msg_dest_droppable(msg))		goto exit;	if (msg_errcode(msg))		goto exit; 	memcpy(&ohdr, msg, msg_hdr_sz(msg));	imp = min_t(uint, imp + 1, TIPC_CRITICAL_IMPORTANCE);	if (msg_isdata(msg))		msg_set_importance(msg, imp);	msg_set_errcode(msg, err);	msg_set_origport(msg, msg_destport(&ohdr));	msg_set_destport(msg, msg_origport(&ohdr));	msg_set_prevnode(msg, own_addr);	if (!msg_short(msg)) {		msg_set_orignode(msg, msg_destnode(&ohdr));		msg_set_destnode(msg, msg_orignode(&ohdr));	}	msg_set_size(msg, msg_hdr_sz(msg) + rdsz);	skb_trim(buf, msg_size(msg));	skb_orphan(buf);	*dnode = msg_orignode(&ohdr);	return true;exit:	kfree_skb(buf);	*dnode = 0;	return false;} /** * tipc_msg_lookup_dest(): try to find new destination for named message * @skb: the buffer containing the message. * @dnode: return value: next-hop node, if destination found * @err: return value: error code to use, if message to be rejected * 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,			  u32 *dnode, int *err){	struct tipc_msg *msg = buf_msg(skb);	u32 dport; 	if (!msg_isdata(msg))		return false;	if (!msg_named(msg))		return false;	*err = -TIPC_ERR_NO_NAME;	if (skb_linearize(skb))		return false;	if (msg_reroute_cnt(msg) > 0)		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);	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 */struct sk_buff *tipc_msg_reassemble(struct sk_buff_head *list){	struct sk_buff *skb;	struct sk_buff *frag = NULL;	struct sk_buff *head = NULL;	int hdr_sz; 	/* Copy header if single buffer */	if (skb_queue_len(list) == 1) {		skb = skb_peek(list);		hdr_sz = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));

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