310 lines
8 KiB
C
310 lines
8 KiB
C
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/* SCTP kernel reference Implementation
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* (C) Copyright IBM Corp. 2003, 2004
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*
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* This file is part of the SCTP kernel reference Implementation
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*
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* This file contains the code relating the the chunk abstraction.
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*
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* The SCTP reference implementation is free software;
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* you can redistribute it and/or modify it under the terms of
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* the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* The SCTP reference implementation is distributed in the hope that it
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* will be useful, but WITHOUT ANY WARRANTY; without even the implied
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* ************************
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* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU CC; see the file COPYING. If not, write to
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* the Free Software Foundation, 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*
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* Please send any bug reports or fixes you make to the
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* email address(es):
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* lksctp developers <lksctp-developers@lists.sourceforge.net>
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*
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* Or submit a bug report through the following website:
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* http://www.sf.net/projects/lksctp
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*
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* Written or modified by:
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* Jon Grimm <jgrimm@us.ibm.com>
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* Sridhar Samudrala <sri@us.ibm.com>
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*
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* Any bugs reported given to us we will try to fix... any fixes shared will
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* be incorporated into the next SCTP release.
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/net.h>
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#include <linux/inet.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <net/sctp/sctp.h>
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#include <net/sctp/sm.h>
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/* This file is mostly in anticipation of future work, but initially
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* populate with fragment tracking for an outbound message.
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*/
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/* Initialize datamsg from memory. */
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static void sctp_datamsg_init(struct sctp_datamsg *msg)
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{
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atomic_set(&msg->refcnt, 1);
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msg->send_failed = 0;
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msg->send_error = 0;
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msg->can_abandon = 0;
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msg->expires_at = 0;
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INIT_LIST_HEAD(&msg->chunks);
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}
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/* Allocate and initialize datamsg. */
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SCTP_STATIC struct sctp_datamsg *sctp_datamsg_new(int gfp)
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{
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struct sctp_datamsg *msg;
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msg = kmalloc(sizeof(struct sctp_datamsg), gfp);
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if (msg)
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sctp_datamsg_init(msg);
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SCTP_DBG_OBJCNT_INC(datamsg);
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return msg;
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}
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/* Final destructruction of datamsg memory. */
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static void sctp_datamsg_destroy(struct sctp_datamsg *msg)
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{
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struct list_head *pos, *temp;
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struct sctp_chunk *chunk;
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struct sctp_sock *sp;
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struct sctp_ulpevent *ev;
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struct sctp_association *asoc = NULL;
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int error = 0, notify;
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/* If we failed, we may need to notify. */
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notify = msg->send_failed ? -1 : 0;
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/* Release all references. */
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list_for_each_safe(pos, temp, &msg->chunks) {
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list_del_init(pos);
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chunk = list_entry(pos, struct sctp_chunk, frag_list);
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/* Check whether we _really_ need to notify. */
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if (notify < 0) {
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asoc = chunk->asoc;
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if (msg->send_error)
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error = msg->send_error;
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else
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error = asoc->outqueue.error;
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sp = sctp_sk(asoc->base.sk);
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notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED,
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&sp->subscribe);
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}
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/* Generate a SEND FAILED event only if enabled. */
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if (notify > 0) {
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int sent;
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if (chunk->has_tsn)
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sent = SCTP_DATA_SENT;
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else
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sent = SCTP_DATA_UNSENT;
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ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent,
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error, GFP_ATOMIC);
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if (ev)
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sctp_ulpq_tail_event(&asoc->ulpq, ev);
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}
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sctp_chunk_put(chunk);
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}
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SCTP_DBG_OBJCNT_DEC(datamsg);
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kfree(msg);
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}
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/* Hold a reference. */
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static void sctp_datamsg_hold(struct sctp_datamsg *msg)
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{
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atomic_inc(&msg->refcnt);
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}
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/* Release a reference. */
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void sctp_datamsg_put(struct sctp_datamsg *msg)
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{
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if (atomic_dec_and_test(&msg->refcnt))
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sctp_datamsg_destroy(msg);
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}
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/* Free a message. Really just give up a reference, the
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* really free happens in sctp_datamsg_destroy().
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*/
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void sctp_datamsg_free(struct sctp_datamsg *msg)
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{
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sctp_datamsg_put(msg);
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}
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/* Hold on to all the fragments until all chunks have been sent. */
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void sctp_datamsg_track(struct sctp_chunk *chunk)
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{
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sctp_chunk_hold(chunk);
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}
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/* Assign a chunk to this datamsg. */
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static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk)
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{
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sctp_datamsg_hold(msg);
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chunk->msg = msg;
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}
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/* A data chunk can have a maximum payload of (2^16 - 20). Break
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* down any such message into smaller chunks. Opportunistically, fragment
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* the chunks down to the current MTU constraints. We may get refragmented
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* later if the PMTU changes, but it is _much better_ to fragment immediately
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* with a reasonable guess than always doing our fragmentation on the
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* soft-interrupt.
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*/
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struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
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struct sctp_sndrcvinfo *sinfo,
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struct msghdr *msgh, int msg_len)
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{
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int max, whole, i, offset, over, err;
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int len, first_len;
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struct sctp_chunk *chunk;
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struct sctp_datamsg *msg;
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struct list_head *pos, *temp;
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__u8 frag;
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msg = sctp_datamsg_new(GFP_KERNEL);
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if (!msg)
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return NULL;
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/* Note: Calculate this outside of the loop, so that all fragments
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* have the same expiration.
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*/
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if (sinfo->sinfo_timetolive) {
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/* sinfo_timetolive is in milliseconds */
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msg->expires_at = jiffies +
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msecs_to_jiffies(sinfo->sinfo_timetolive);
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msg->can_abandon = 1;
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SCTP_DEBUG_PRINTK("%s: msg:%p expires_at: %ld jiffies:%ld\n",
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__FUNCTION__, msg, msg->expires_at, jiffies);
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}
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max = asoc->frag_point;
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whole = 0;
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first_len = max;
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/* Encourage Cookie-ECHO bundling. */
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if (asoc->state < SCTP_STATE_COOKIE_ECHOED) {
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whole = msg_len / (max - SCTP_ARBITRARY_COOKIE_ECHO_LEN);
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/* Account for the DATA to be bundled with the COOKIE-ECHO. */
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if (whole) {
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first_len = max - SCTP_ARBITRARY_COOKIE_ECHO_LEN;
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msg_len -= first_len;
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whole = 1;
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}
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}
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/* How many full sized? How many bytes leftover? */
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whole += msg_len / max;
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over = msg_len % max;
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offset = 0;
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if ((whole > 1) || (whole && over))
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SCTP_INC_STATS_USER(SCTP_MIB_FRAGUSRMSGS);
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/* Create chunks for all the full sized DATA chunks. */
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for (i=0, len=first_len; i < whole; i++) {
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frag = SCTP_DATA_MIDDLE_FRAG;
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if (0 == i)
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frag |= SCTP_DATA_FIRST_FRAG;
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if ((i == (whole - 1)) && !over)
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frag |= SCTP_DATA_LAST_FRAG;
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chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0);
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if (!chunk)
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goto errout;
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err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov);
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if (err < 0)
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goto errout;
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offset += len;
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/* Put the chunk->skb back into the form expected by send. */
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__skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
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- (__u8 *)chunk->skb->data);
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sctp_datamsg_assign(msg, chunk);
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list_add_tail(&chunk->frag_list, &msg->chunks);
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/* The first chunk, the first chunk was likely short
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* to allow bundling, so reset to full size.
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*/
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if (0 == i)
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len = max;
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}
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/* .. now the leftover bytes. */
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if (over) {
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if (!whole)
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frag = SCTP_DATA_NOT_FRAG;
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else
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frag = SCTP_DATA_LAST_FRAG;
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chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0);
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if (!chunk)
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goto errout;
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err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov);
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/* Put the chunk->skb back into the form expected by send. */
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__skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
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- (__u8 *)chunk->skb->data);
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if (err < 0)
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goto errout;
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sctp_datamsg_assign(msg, chunk);
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list_add_tail(&chunk->frag_list, &msg->chunks);
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}
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return msg;
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errout:
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list_for_each_safe(pos, temp, &msg->chunks) {
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list_del_init(pos);
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chunk = list_entry(pos, struct sctp_chunk, frag_list);
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sctp_chunk_free(chunk);
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}
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sctp_datamsg_free(msg);
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return NULL;
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}
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/* Check whether this message has expired. */
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int sctp_chunk_abandoned(struct sctp_chunk *chunk)
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{
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struct sctp_datamsg *msg = chunk->msg;
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if (!msg->can_abandon)
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return 0;
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if (time_after(jiffies, msg->expires_at))
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return 1;
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return 0;
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}
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/* This chunk (and consequently entire message) has failed in its sending. */
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void sctp_chunk_fail(struct sctp_chunk *chunk, int error)
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{
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chunk->msg->send_failed = 1;
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chunk->msg->send_error = error;
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}
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