android_kernel_xiaomi_sm8350/net/sctp/chunk.c
Vlad Yasevich 60c778b259 [SCTP]: Stop claiming that this is a "reference implementation"
I was notified by Randy Stewart that lksctp claims to be
"the reference implementation".  First of all, "the
refrence implementation" was the original implementation
of SCTP in usersapce written ty Randy and a few others.
Second, after looking at the definiton of 'reference implementation',
we don't really meet the requirements.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
2008-02-05 10:59:07 -05:00

322 lines
8.3 KiB
C

/* 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 <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->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;
}
/* 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);
}
/* Free a message. Really just give up a reference, the
* really free happens in sctp_datamsg_destroy().
*/
void sctp_datamsg_free(struct sctp_datamsg *msg)
{
sctp_datamsg_put(msg);
}
/* Hold on to all the fragments until all chunks have been sent. */
void sctp_datamsg_track(struct sctp_chunk *chunk)
{
sctp_chunk_hold(chunk);
}
/* 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;
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",
__FUNCTION__, msg, msg->expires_at, jiffies);
}
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 -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
hmac_desc->hmac_len);
}
whole = 0;
first_len = max;
/* Encourage Cookie-ECHO bundling. */
if (asoc->state < SCTP_STATE_COOKIE_ECHOED) {
whole = msg_len / (max - SCTP_ARBITRARY_COOKIE_ECHO_LEN);
/* Account for the DATA to be bundled with the COOKIE-ECHO. */
if (whole) {
first_len = max - SCTP_ARBITRARY_COOKIE_ECHO_LEN;
msg_len -= first_len;
whole = 1;
}
}
/* 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;
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;
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_free(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;
}