linux/net/sctp/chunk.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* 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.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <[email protected]>
 *
 * Written or modified by:
 *    Jon Grimm             <[email protected]>
 *    Sridhar Samudrala     <[email protected]>
 */

#define pr_fmt(fmt) …

#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)
{ … }

/* Allocate and initialize datamsg. */
static struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp)
{ … }

void sctp_datamsg_free(struct sctp_datamsg *msg)
{ … }

/* Final destructruction of datamsg memory. */
static void sctp_datamsg_destroy(struct sctp_datamsg *msg)
{ … }

/* Hold a reference. */
static void sctp_datamsg_hold(struct sctp_datamsg *msg)
{ … }

/* Release a reference. */
void sctp_datamsg_put(struct sctp_datamsg *msg)
{ … }

/* Assign a chunk to this datamsg. */
static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk)
{ … }


/* 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 iov_iter *from)
{ … }

/* Check whether this message has expired. */
int sctp_chunk_abandoned(struct sctp_chunk *chunk)
{ … }

/* This chunk (and consequently entire message) has failed in its sending. */
void sctp_chunk_fail(struct sctp_chunk *chunk, int error)
{ … }