net/tipc/msg.c

0001 /*
0002  * net/tipc/msg.c: TIPC message header routines
0003  *
0004  * Copyright (c) 2000-2006, 2014-2015, Ericsson AB
0005  * Copyright (c) 2005, 2010-2011, Wind River Systems
0006  * All rights reserved.
0007  *
0008  * Redistribution and use in source and binary forms, with or without
0009  * modification, are permitted provided that the following conditions are met:
0010  *
0011  * 1. Redistributions of source code must retain the above copyright
0012  *    notice, this list of conditions and the following disclaimer.
0013  * 2. Redistributions in binary form must reproduce the above copyright
0014  *    notice, this list of conditions and the following disclaimer in the
0015  *    documentation and/or other materials provided with the distribution.
0016  * 3. Neither the names of the copyright holders nor the names of its
0017  *    contributors may be used to endorse or promote products derived from
0018  *    this software without specific prior written permission.
0019  *
0020  * Alternatively, this software may be distributed under the terms of the
0021  * GNU General Public License ("GPL") version 2 as published by the Free
0022  * Software Foundation.
0023  *
0024  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0025  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0026  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0027  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0028  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0029  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0030  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0031  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0032  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0033  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0034  * POSSIBILITY OF SUCH DAMAGE.
0035  */
0036
0037 #include <net/sock.h>
0038 #include "core.h"
0039 #include "msg.h"
0040 #include "addr.h"
0041 #include "name_table.h"
0042 #include "crypto.h"
0043
0044 #define BUF_ALIGN(x) ALIGN(x, 4)
0045 #define MAX_FORWARD_SIZE 1024
0046 #ifdef CONFIG_TIPC_CRYPTO
0047 #define BUF_HEADROOM ALIGN(((LL_MAX_HEADER + 48) + EHDR_MAX_SIZE), 16)
0048 #define BUF_OVERHEAD (BUF_HEADROOM + TIPC_AES_GCM_TAG_SIZE)
0049 #else
0050 #define BUF_HEADROOM (LL_MAX_HEADER + 48)
0051 #define BUF_OVERHEAD BUF_HEADROOM
0052 #endif
0053
0054 const int one_page_mtu = PAGE_SIZE - SKB_DATA_ALIGN(BUF_OVERHEAD) -
0055              SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
0056
0057 /**
0058  * tipc_buf_acquire - creates a TIPC message buffer
0059  * @size: message size (including TIPC header)
0060  * @gfp: memory allocation flags
0061  *
0062  * Return: a new buffer with data pointers set to the specified size.
0063  *
0064  * NOTE:
0065  * Headroom is reserved to allow prepending of a data link header.
0066  * There may also be unrequested tailroom present at the buffer's end.
0067  */
0068 struct sk_buff *tipc_buf_acquire(u32 size, gfp_t gfp)
0069 {
0070     struct sk_buff *skb;
0071
0072     skb = alloc_skb_fclone(BUF_OVERHEAD + size, gfp);
0073     if (skb) {
0074         skb_reserve(skb, BUF_HEADROOM);
0075         skb_put(skb, size);
0076         skb->next = NULL;
0077     }
0078     return skb;
0079 }
0080
0081 void tipc_msg_init(u32 own_node, struct tipc_msg *m, u32 user, u32 type,
0082            u32 hsize, u32 dnode)
0083 {
0084     memset(m, 0, hsize);
0085     msg_set_version(m);
0086     msg_set_user(m, user);
0087     msg_set_hdr_sz(m, hsize);
0088     msg_set_size(m, hsize);
0089     msg_set_prevnode(m, own_node);
0090     msg_set_type(m, type);
0091     if (hsize > SHORT_H_SIZE) {
0092         msg_set_orignode(m, own_node);
0093         msg_set_destnode(m, dnode);
0094     }
0095 }
0096
0097 struct sk_buff *tipc_msg_create(uint user, uint type,
0098                 uint hdr_sz, uint data_sz, u32 dnode,
0099                 u32 onode, u32 dport, u32 oport, int errcode)
0100 {
0101     struct tipc_msg *msg;
0102     struct sk_buff *buf;
0103
0104     buf = tipc_buf_acquire(hdr_sz + data_sz, GFP_ATOMIC);
0105     if (unlikely(!buf))
0106         return NULL;
0107
0108     msg = buf_msg(buf);
0109     tipc_msg_init(onode, msg, user, type, hdr_sz, dnode);
0110     msg_set_size(msg, hdr_sz + data_sz);
0111     msg_set_origport(msg, oport);
0112     msg_set_destport(msg, dport);
0113     msg_set_errcode(msg, errcode);
0114     return buf;
0115 }
0116
0117 /* tipc_buf_append(): Append a buffer to the fragment list of another buffer
0118  * @*headbuf: in:  NULL for first frag, otherwise value returned from prev call
0119  *            out: set when successful non-complete reassembly, otherwise NULL
0120  * @*buf:     in:  the buffer to append. Always defined
0121  *            out: head buf after successful complete reassembly, otherwise NULL
0122  * Returns 1 when reassembly complete, otherwise 0
0123  */
0124 int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
0125 {
0126     struct sk_buff *head = *headbuf;
0127     struct sk_buff *frag = *buf;
0128     struct sk_buff *tail = NULL;
0129     struct tipc_msg *msg;
0130     u32 fragid;
0131     int delta;
0132     bool headstolen;
0133
0134     if (!frag)
0135         goto err;
0136
0137     msg = buf_msg(frag);
0138     fragid = msg_type(msg);
0139     frag->next = NULL;
0140     skb_pull(frag, msg_hdr_sz(msg));
0141
0142     if (fragid == FIRST_FRAGMENT) {
0143         if (unlikely(head))
0144             goto err;
0145         *buf = NULL;
0146         if (skb_has_frag_list(frag) && __skb_linearize(frag))
0147             goto err;
0148         frag = skb_unshare(frag, GFP_ATOMIC);
0149         if (unlikely(!frag))
0150             goto err;
0151         head = *headbuf = frag;
0152         TIPC_SKB_CB(head)->tail = NULL;
0153         return 0;
0154     }
0155
0156     if (!head)
0157         goto err;
0158
0159     if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
0160         kfree_skb_partial(frag, headstolen);
0161     } else {
0162         tail = TIPC_SKB_CB(head)->tail;
0163         if (!skb_has_frag_list(head))
0164             skb_shinfo(head)->frag_list = frag;
0165         else
0166             tail->next = frag;
0167         head->truesize += frag->truesize;
0168         head->data_len += frag->len;
0169         head->len += frag->len;
0170         TIPC_SKB_CB(head)->tail = frag;
0171     }
0172
0173     if (fragid == LAST_FRAGMENT) {
0174         TIPC_SKB_CB(head)->validated = 0;
0175         if (unlikely(!tipc_msg_validate(&head)))
0176             goto err;
0177         *buf = head;
0178         TIPC_SKB_CB(head)->tail = NULL;
0179         *headbuf = NULL;
0180         return 1;
0181     }
0182     *buf = NULL;
0183     return 0;
0184 err:
0185     kfree_skb(*buf);
0186     kfree_skb(*headbuf);
0187     *buf = *headbuf = NULL;
0188     return 0;
0189 }
0190
0191 /**
0192  * tipc_msg_append(): Append data to tail of an existing buffer queue
0193  * @_hdr: header to be used
0194  * @m: the data to be appended
0195  * @mss: max allowable size of buffer
0196  * @dlen: size of data to be appended
0197  * @txq: queue to append to
0198  *
0199  * Return: the number of 1k blocks appended or errno value
0200  */
0201 int tipc_msg_append(struct tipc_msg *_hdr, struct msghdr *m, int dlen,
0202             int mss, struct sk_buff_head *txq)
0203 {
0204     struct sk_buff *skb;
0205     int accounted, total, curr;
0206     int mlen, cpy, rem = dlen;
0207     struct tipc_msg *hdr;
0208
0209     skb = skb_peek_tail(txq);
0210     accounted = skb ? msg_blocks(buf_msg(skb)) : 0;
0211     total = accounted;
0212
0213     do {
0214         if (!skb || skb->len >= mss) {
0215             skb = tipc_buf_acquire(mss, GFP_KERNEL);
0216             if (unlikely(!skb))
0217                 return -ENOMEM;
0218             skb_orphan(skb);
0219             skb_trim(skb, MIN_H_SIZE);
0220             hdr = buf_msg(skb);
0221             skb_copy_to_linear_data(skb, _hdr, MIN_H_SIZE);
0222             msg_set_hdr_sz(hdr, MIN_H_SIZE);
0223             msg_set_size(hdr, MIN_H_SIZE);
0224             __skb_queue_tail(txq, skb);
0225             total += 1;
0226         }
0227         hdr = buf_msg(skb);
0228         curr = msg_blocks(hdr);
0229         mlen = msg_size(hdr);
0230         cpy = min_t(size_t, rem, mss - mlen);
0231         if (cpy != copy_from_iter(skb->data + mlen, cpy, &m->msg_iter))
0232             return -EFAULT;
0233         msg_set_size(hdr, mlen + cpy);
0234         skb_put(skb, cpy);
0235         rem -= cpy;
0236         total += msg_blocks(hdr) - curr;
0237     } while (rem > 0);
0238     return total - accounted;
0239 }
0240
0241 /* tipc_msg_validate - validate basic format of received message
0242  *
0243  * This routine ensures a TIPC message has an acceptable header, and at least
0244  * as much data as the header indicates it should.  The routine also ensures
0245  * that the entire message header is stored in the main fragment of the message
0246  * buffer, to simplify future access to message header fields.
0247  *
0248  * Note: Having extra info present in the message header or data areas is OK.
0249  * TIPC will ignore the excess, under the assumption that it is optional info
0250  * introduced by a later release of the protocol.
0251  */
0252 bool tipc_msg_validate(struct sk_buff **_skb)
0253 {
0254     struct sk_buff *skb = *_skb;
0255     struct tipc_msg *hdr;
0256     int msz, hsz;
0257
0258     /* Ensure that flow control ratio condition is satisfied */
0259     if (unlikely(skb->truesize / buf_roundup_len(skb) >= 4)) {
0260         skb = skb_copy_expand(skb, BUF_HEADROOM, 0, GFP_ATOMIC);
0261         if (!skb)
0262             return false;
0263         kfree_skb(*_skb);
0264         *_skb = skb;
0265     }
0266
0267     if (unlikely(TIPC_SKB_CB(skb)->validated))
0268         return true;
0269
0270     if (unlikely(!pskb_may_pull(skb, MIN_H_SIZE)))
0271         return false;
0272
0273     hsz = msg_hdr_sz(buf_msg(skb));
0274     if (unlikely(hsz < MIN_H_SIZE) || (hsz > MAX_H_SIZE))
0275         return false;
0276     if (unlikely(!pskb_may_pull(skb, hsz)))
0277         return false;
0278
0279     hdr = buf_msg(skb);
0280     if (unlikely(msg_version(hdr) != TIPC_VERSION))
0281         return false;
0282
0283     msz = msg_size(hdr);
0284     if (unlikely(msz < hsz))
0285         return false;
0286     if (unlikely((msz - hsz) > TIPC_MAX_USER_MSG_SIZE))
0287         return false;
0288     if (unlikely(skb->len < msz))
0289         return false;
0290
0291     TIPC_SKB_CB(skb)->validated = 1;
0292     return true;
0293 }
0294
0295 /**
0296  * tipc_msg_fragment - build a fragment skb list for TIPC message
0297  *
0298  * @skb: TIPC message skb
0299  * @hdr: internal msg header to be put on the top of the fragments
0300  * @pktmax: max size of a fragment incl. the header
0301  * @frags: returned fragment skb list
0302  *
0303  * Return: 0 if the fragmentation is successful, otherwise: -EINVAL
0304  * or -ENOMEM
0305  */
0306 int tipc_msg_fragment(struct sk_buff *skb, const struct tipc_msg *hdr,
0307               int pktmax, struct sk_buff_head *frags)
0308 {
0309     int pktno, nof_fragms, dsz, dmax, eat;
0310     struct tipc_msg *_hdr;
0311     struct sk_buff *_skb;
0312     u8 *data;
0313
0314     /* Non-linear buffer? */
0315     if (skb_linearize(skb))
0316         return -ENOMEM;
0317
0318     data = (u8 *)skb->data;
0319     dsz = msg_size(buf_msg(skb));
0320     dmax = pktmax - INT_H_SIZE;
0321     if (dsz <= dmax || !dmax)
0322         return -EINVAL;
0323
0324     nof_fragms = dsz / dmax + 1;
0325     for (pktno = 1; pktno <= nof_fragms; pktno++) {
0326         if (pktno < nof_fragms)
0327             eat = dmax;
0328         else
0329             eat = dsz % dmax;
0330         /* Allocate a new fragment */
0331         _skb = tipc_buf_acquire(INT_H_SIZE + eat, GFP_ATOMIC);
0332         if (!_skb)
0333             goto error;
0334         skb_orphan(_skb);
0335         __skb_queue_tail(frags, _skb);
0336         /* Copy header & data to the fragment */
0337         skb_copy_to_linear_data(_skb, hdr, INT_H_SIZE);
0338         skb_copy_to_linear_data_offset(_skb, INT_H_SIZE, data, eat);
0339         data += eat;
0340         /* Update the fragment's header */
0341         _hdr = buf_msg(_skb);
0342         msg_set_fragm_no(_hdr, pktno);
0343         msg_set_nof_fragms(_hdr, nof_fragms);
0344         msg_set_size(_hdr, INT_H_SIZE + eat);
0345     }
0346     return 0;
0347
0348 error:
0349     __skb_queue_purge(frags);
0350     __skb_queue_head_init(frags);
0351     return -ENOMEM;
0352 }
0353
0354 /**
0355  * tipc_msg_build - create buffer chain containing specified header and data
0356  * @mhdr: Message header, to be prepended to data
0357  * @m: User message
0358  * @offset: buffer offset for fragmented messages (FIXME)
0359  * @dsz: Total length of user data
0360  * @pktmax: Max packet size that can be used
0361  * @list: Buffer or chain of buffers to be returned to caller
0362  *
0363  * Note that the recursive call we are making here is safe, since it can
0364  * logically go only one further level down.
0365  *
0366  * Return: message data size or errno: -ENOMEM, -EFAULT
0367  */
0368 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m, int offset,
0369            int dsz, int pktmax, struct sk_buff_head *list)
0370 {
0371     int mhsz = msg_hdr_sz(mhdr);
0372     struct tipc_msg pkthdr;
0373     int msz = mhsz + dsz;
0374     int pktrem = pktmax;
0375     struct sk_buff *skb;
0376     int drem = dsz;
0377     int pktno = 1;
0378     char *pktpos;
0379     int pktsz;
0380     int rc;
0381
0382     msg_set_size(mhdr, msz);
0383
0384     /* No fragmentation needed? */
0385     if (likely(msz <= pktmax)) {
0386         skb = tipc_buf_acquire(msz, GFP_KERNEL);
0387
0388         /* Fall back to smaller MTU if node local message */
0389         if (unlikely(!skb)) {
0390             if (pktmax != MAX_MSG_SIZE)
0391                 return -ENOMEM;
0392             rc = tipc_msg_build(mhdr, m, offset, dsz,
0393                         one_page_mtu, list);
0394             if (rc != dsz)
0395                 return rc;
0396             if (tipc_msg_assemble(list))
0397                 return dsz;
0398             return -ENOMEM;
0399         }
0400         skb_orphan(skb);
0401         __skb_queue_tail(list, skb);
0402         skb_copy_to_linear_data(skb, mhdr, mhsz);
0403         pktpos = skb->data + mhsz;
0404         if (copy_from_iter_full(pktpos, dsz, &m->msg_iter))
0405             return dsz;
0406         rc = -EFAULT;
0407         goto error;
0408     }
0409
0410     /* Prepare reusable fragment header */
0411     tipc_msg_init(msg_prevnode(mhdr), &pkthdr, MSG_FRAGMENTER,
0412               FIRST_FRAGMENT, INT_H_SIZE, msg_destnode(mhdr));
0413     msg_set_size(&pkthdr, pktmax);
0414     msg_set_fragm_no(&pkthdr, pktno);
0415     msg_set_importance(&pkthdr, msg_importance(mhdr));
0416
0417     /* Prepare first fragment */
0418     skb = tipc_buf_acquire(pktmax, GFP_KERNEL);
0419     if (!skb)
0420         return -ENOMEM;
0421     skb_orphan(skb);
0422     __skb_queue_tail(list, skb);
0423     pktpos = skb->data;
0424     skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
0425     pktpos += INT_H_SIZE;
0426     pktrem -= INT_H_SIZE;
0427     skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
0428     pktpos += mhsz;
0429     pktrem -= mhsz;
0430
0431     do {
0432         if (drem < pktrem)
0433             pktrem = drem;
0434
0435         if (!copy_from_iter_full(pktpos, pktrem, &m->msg_iter)) {
0436             rc = -EFAULT;
0437             goto error;
0438         }
0439         drem -= pktrem;
0440
0441         if (!drem)
0442             break;
0443
0444         /* Prepare new fragment: */
0445         if (drem < (pktmax - INT_H_SIZE))
0446             pktsz = drem + INT_H_SIZE;
0447         else
0448             pktsz = pktmax;
0449         skb = tipc_buf_acquire(pktsz, GFP_KERNEL);
0450         if (!skb) {
0451             rc = -ENOMEM;
0452             goto error;
0453         }
0454         skb_orphan(skb);
0455         __skb_queue_tail(list, skb);
0456         msg_set_type(&pkthdr, FRAGMENT);
0457         msg_set_size(&pkthdr, pktsz);
0458         msg_set_fragm_no(&pkthdr, ++pktno);
0459         skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
0460         pktpos = skb->data + INT_H_SIZE;
0461         pktrem = pktsz - INT_H_SIZE;
0462
0463     } while (1);
0464     msg_set_type(buf_msg(skb), LAST_FRAGMENT);
0465     return dsz;
0466 error:
0467     __skb_queue_purge(list);
0468     __skb_queue_head_init(list);
0469     return rc;
0470 }
0471
0472 /**
0473  * tipc_msg_bundle - Append contents of a buffer to tail of an existing one
0474  * @bskb: the bundle buffer to append to
0475  * @msg: message to be appended
0476  * @max: max allowable size for the bundle buffer
0477  *
0478  * Return: "true" if bundling has been performed, otherwise "false"
0479  */
0480 static bool tipc_msg_bundle(struct sk_buff *bskb, struct tipc_msg *msg,
0481                 u32 max)
0482 {
0483     struct tipc_msg *bmsg = buf_msg(bskb);
0484     u32 msz, bsz, offset, pad;
0485
0486     msz = msg_size(msg);
0487     bsz = msg_size(bmsg);
0488     offset = BUF_ALIGN(bsz);
0489     pad = offset - bsz;
0490
0491     if (unlikely(skb_tailroom(bskb) < (pad + msz)))
0492         return false;
0493     if (unlikely(max < (offset + msz)))
0494         return false;
0495
0496     skb_put(bskb, pad + msz);
0497     skb_copy_to_linear_data_offset(bskb, offset, msg, msz);
0498     msg_set_size(bmsg, offset + msz);
0499     msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
0500     return true;
0501 }
0502
0503 /**
0504  * tipc_msg_try_bundle - Try to bundle a new message to the last one
0505  * @tskb: the last/target message to which the new one will be appended
0506  * @skb: the new message skb pointer
0507  * @mss: max message size (header inclusive)
0508  * @dnode: destination node for the message
0509  * @new_bundle: if this call made a new bundle or not
0510  *
0511  * Return: "true" if the new message skb is potential for bundling this time or
0512  * later, in the case a bundling has been done this time, the skb is consumed
0513  * (the skb pointer = NULL).
0514  * Otherwise, "false" if the skb cannot be bundled at all.
0515  */
0516 bool tipc_msg_try_bundle(struct sk_buff *tskb, struct sk_buff **skb, u32 mss,
0517              u32 dnode, bool *new_bundle)
0518 {
0519     struct tipc_msg *msg, *inner, *outer;
0520     u32 tsz;
0521
0522     /* First, check if the new buffer is suitable for bundling */
0523     msg = buf_msg(*skb);
0524     if (msg_user(msg) == MSG_FRAGMENTER)
0525         return false;
0526     if (msg_user(msg) == TUNNEL_PROTOCOL)
0527         return false;
0528     if (msg_user(msg) == BCAST_PROTOCOL)
0529         return false;
0530     if (mss <= INT_H_SIZE + msg_size(msg))
0531         return false;
0532
0533     /* Ok, but the last/target buffer can be empty? */
0534     if (unlikely(!tskb))
0535         return true;
0536
0537     /* Is it a bundle already? Try to bundle the new message to it */
0538     if (msg_user(buf_msg(tskb)) == MSG_BUNDLER) {
0539         *new_bundle = false;
0540         goto bundle;
0541     }
0542
0543     /* Make a new bundle of the two messages if possible */
0544     tsz = msg_size(buf_msg(tskb));
0545     if (unlikely(mss < BUF_ALIGN(INT_H_SIZE + tsz) + msg_size(msg)))
0546         return true;
0547     if (unlikely(pskb_expand_head(tskb, INT_H_SIZE, mss - tsz - INT_H_SIZE,
0548                       GFP_ATOMIC)))
0549         return true;
0550     inner = buf_msg(tskb);
0551     skb_push(tskb, INT_H_SIZE);
0552     outer = buf_msg(tskb);
0553     tipc_msg_init(msg_prevnode(inner), outer, MSG_BUNDLER, 0, INT_H_SIZE,
0554               dnode);
0555     msg_set_importance(outer, msg_importance(inner));
0556     msg_set_size(outer, INT_H_SIZE + tsz);
0557     msg_set_msgcnt(outer, 1);
0558     *new_bundle = true;
0559
0560 bundle:
0561     if (likely(tipc_msg_bundle(tskb, msg, mss))) {
0562         consume_skb(*skb);
0563         *skb = NULL;
0564     }
0565     return true;
0566 }
0567
0568 /**
0569  *  tipc_msg_extract(): extract bundled inner packet from buffer
0570  *  @skb: buffer to be extracted from.
0571  *  @iskb: extracted inner buffer, to be returned
0572  *  @pos: position in outer message of msg to be extracted.
0573  *  Returns position of next msg.
0574  *  Consumes outer buffer when last packet extracted
0575  *  Return: true when there is an extracted buffer, otherwise false
0576  */
0577 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
0578 {
0579     struct tipc_msg *hdr, *ihdr;
0580     int imsz;
0581
0582     *iskb = NULL;
0583     if (unlikely(skb_linearize(skb)))
0584         goto none;
0585
0586     hdr = buf_msg(skb);
0587     if (unlikely(*pos > (msg_data_sz(hdr) - MIN_H_SIZE)))
0588         goto none;
0589
0590     ihdr = (struct tipc_msg *)(msg_data(hdr) + *pos);
0591     imsz = msg_size(ihdr);
0592
0593     if ((*pos + imsz) > msg_data_sz(hdr))
0594         goto none;
0595
0596     *iskb = tipc_buf_acquire(imsz, GFP_ATOMIC);
0597     if (!*iskb)
0598         goto none;
0599
0600     skb_copy_to_linear_data(*iskb, ihdr, imsz);
0601     if (unlikely(!tipc_msg_validate(iskb)))
0602         goto none;
0603
0604     *pos += BUF_ALIGN(imsz);
0605     return true;
0606 none:
0607     kfree_skb(skb);
0608     kfree_skb(*iskb);
0609     *iskb = NULL;
0610     return false;
0611 }
0612
0613 /**
0614  * tipc_msg_reverse(): swap source and destination addresses and add error code
0615  * @own_node: originating node id for reversed message
0616  * @skb:  buffer containing message to be reversed; will be consumed
0617  * @err:  error code to be set in message, if any
0618  * Replaces consumed buffer with new one when successful
0619  * Return: true if success, otherwise false
0620  */
0621 bool tipc_msg_reverse(u32 own_node,  struct sk_buff **skb, int err)
0622 {
0623     struct sk_buff *_skb = *skb;
0624     struct tipc_msg *_hdr, *hdr;
0625     int hlen, dlen;
0626
0627     if (skb_linearize(_skb))
0628         goto exit;
0629     _hdr = buf_msg(_skb);
0630     dlen = min_t(uint, msg_data_sz(_hdr), MAX_FORWARD_SIZE);
0631     hlen = msg_hdr_sz(_hdr);
0632
0633     if (msg_dest_droppable(_hdr))
0634         goto exit;
0635     if (msg_errcode(_hdr))
0636         goto exit;
0637
0638     /* Never return SHORT header */
0639     if (hlen == SHORT_H_SIZE)
0640         hlen = BASIC_H_SIZE;
0641
0642     /* Don't return data along with SYN+, - sender has a clone */
0643     if (msg_is_syn(_hdr) && err == TIPC_ERR_OVERLOAD)
0644         dlen = 0;
0645
0646     /* Allocate new buffer to return */
0647     *skb = tipc_buf_acquire(hlen + dlen, GFP_ATOMIC);
0648     if (!*skb)
0649         goto exit;
0650     memcpy((*skb)->data, _skb->data, msg_hdr_sz(_hdr));
0651     memcpy((*skb)->data + hlen, msg_data(_hdr), dlen);
0652
0653     /* Build reverse header in new buffer */
0654     hdr = buf_msg(*skb);
0655     msg_set_hdr_sz(hdr, hlen);
0656     msg_set_errcode(hdr, err);
0657     msg_set_non_seq(hdr, 0);
0658     msg_set_origport(hdr, msg_destport(_hdr));
0659     msg_set_destport(hdr, msg_origport(_hdr));
0660     msg_set_destnode(hdr, msg_prevnode(_hdr));
0661     msg_set_prevnode(hdr, own_node);
0662     msg_set_orignode(hdr, own_node);
0663     msg_set_size(hdr, hlen + dlen);
0664     skb_orphan(_skb);
0665     kfree_skb(_skb);
0666     return true;
0667 exit:
0668     kfree_skb(_skb);
0669     *skb = NULL;
0670     return false;
0671 }
0672
0673 bool tipc_msg_skb_clone(struct sk_buff_head *msg, struct sk_buff_head *cpy)
0674 {
0675     struct sk_buff *skb, *_skb;
0676
0677     skb_queue_walk(msg, skb) {
0678         _skb = skb_clone(skb, GFP_ATOMIC);
0679         if (!_skb) {
0680             __skb_queue_purge(cpy);
0681             pr_err_ratelimited("Failed to clone buffer chain\n");
0682             return false;
0683         }
0684         __skb_queue_tail(cpy, _skb);
0685     }
0686     return true;
0687 }
0688
0689 /**
0690  * tipc_msg_lookup_dest(): try to find new destination for named message
0691  * @net: pointer to associated network namespace
0692  * @skb: the buffer containing the message.
0693  * @err: error code to be used by caller if lookup fails
0694  * Does not consume buffer
0695  * Return: true if a destination is found, false otherwise
0696  */
0697 bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, int *err)
0698 {
0699     struct tipc_msg *msg = buf_msg(skb);
0700     u32 scope = msg_lookup_scope(msg);
0701     u32 self = tipc_own_addr(net);
0702     u32 inst = msg_nameinst(msg);
0703     struct tipc_socket_addr sk;
0704     struct tipc_uaddr ua;
0705
0706     if (!msg_isdata(msg))
0707         return false;
0708     if (!msg_named(msg))
0709         return false;
0710     if (msg_errcode(msg))
0711         return false;
0712     *err = TIPC_ERR_NO_NAME;
0713     if (skb_linearize(skb))
0714         return false;
0715     msg = buf_msg(skb);
0716     if (msg_reroute_cnt(msg))
0717         return false;
0718     tipc_uaddr(&ua, TIPC_SERVICE_RANGE, scope,
0719            msg_nametype(msg), inst, inst);
0720     sk.node = tipc_scope2node(net, scope);
0721     if (!tipc_nametbl_lookup_anycast(net, &ua, &sk))
0722         return false;
0723     msg_incr_reroute_cnt(msg);
0724     if (sk.node != self)
0725         msg_set_prevnode(msg, self);
0726     msg_set_destnode(msg, sk.node);
0727     msg_set_destport(msg, sk.ref);
0728     *err = TIPC_OK;
0729
0730     return true;
0731 }
0732
0733 /* tipc_msg_assemble() - assemble chain of fragments into one message
0734  */
0735 bool tipc_msg_assemble(struct sk_buff_head *list)
0736 {
0737     struct sk_buff *skb, *tmp = NULL;
0738
0739     if (skb_queue_len(list) == 1)
0740         return true;
0741
0742     while ((skb = __skb_dequeue(list))) {
0743         skb->next = NULL;
0744         if (tipc_buf_append(&tmp, &skb)) {
0745             __skb_queue_tail(list, skb);
0746             return true;
0747         }
0748         if (!tmp)
0749             break;
0750     }
0751     __skb_queue_purge(list);
0752     __skb_queue_head_init(list);
0753     pr_warn("Failed do assemble buffer\n");
0754     return false;
0755 }
0756
0757 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
0758  *                         reassemble the clones into one message
0759  */
0760 bool tipc_msg_reassemble(struct sk_buff_head *list, struct sk_buff_head *rcvq)
0761 {
0762     struct sk_buff *skb, *_skb;
0763     struct sk_buff *frag = NULL;
0764     struct sk_buff *head = NULL;
0765     int hdr_len;
0766
0767     /* Copy header if single buffer */
0768     if (skb_queue_len(list) == 1) {
0769         skb = skb_peek(list);
0770         hdr_len = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
0771         _skb = __pskb_copy(skb, hdr_len, GFP_ATOMIC);
0772         if (!_skb)
0773             return false;
0774         __skb_queue_tail(rcvq, _skb);
0775         return true;
0776     }
0777
0778     /* Clone all fragments and reassemble */
0779     skb_queue_walk(list, skb) {
0780         frag = skb_clone(skb, GFP_ATOMIC);
0781         if (!frag)
0782             goto error;
0783         frag->next = NULL;
0784         if (tipc_buf_append(&head, &frag))
0785             break;
0786         if (!head)
0787             goto error;
0788     }
0789     __skb_queue_tail(rcvq, frag);
0790     return true;
0791 error:
0792     pr_warn("Failed do clone local mcast rcv buffer\n");
0793     kfree_skb(head);
0794     return false;
0795 }
0796
0797 bool tipc_msg_pskb_copy(u32 dst, struct sk_buff_head *msg,
0798             struct sk_buff_head *cpy)
0799 {
0800     struct sk_buff *skb, *_skb;
0801
0802     skb_queue_walk(msg, skb) {
0803         _skb = pskb_copy(skb, GFP_ATOMIC);
0804         if (!_skb) {
0805             __skb_queue_purge(cpy);
0806             return false;
0807         }
0808         msg_set_destnode(buf_msg(_skb), dst);
0809         __skb_queue_tail(cpy, _skb);
0810     }
0811     return true;
0812 }
0813
0814 /* tipc_skb_queue_sorted(); sort pkt into list according to sequence number
0815  * @list: list to be appended to
0816  * @seqno: sequence number of buffer to add
0817  * @skb: buffer to add
0818  */
0819 bool __tipc_skb_queue_sorted(struct sk_buff_head *list, u16 seqno,
0820                  struct sk_buff *skb)
0821 {
0822     struct sk_buff *_skb, *tmp;
0823
0824     if (skb_queue_empty(list) || less(seqno, buf_seqno(skb_peek(list)))) {
0825         __skb_queue_head(list, skb);
0826         return true;
0827     }
0828
0829     if (more(seqno, buf_seqno(skb_peek_tail(list)))) {
0830         __skb_queue_tail(list, skb);
0831         return true;
0832     }
0833
0834     skb_queue_walk_safe(list, _skb, tmp) {
0835         if (more(seqno, buf_seqno(_skb)))
0836             continue;
0837         if (seqno == buf_seqno(_skb))
0838             break;
0839         __skb_queue_before(list, _skb, skb);
0840         return true;
0841     }
0842     kfree_skb(skb);
0843     return false;
0844 }
0845
0846 void tipc_skb_reject(struct net *net, int err, struct sk_buff *skb,
0847              struct sk_buff_head *xmitq)
0848 {
0849     if (tipc_msg_reverse(tipc_own_addr(net), &skb, err))
0850         __skb_queue_tail(xmitq, skb);
0851 }