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