linux/net/sctp/output.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* SCTP kernel implementation
 * (C) Copyright IBM Corp. 2001, 2004
 * Copyright (c) 1999-2000 Cisco, Inc.
 * Copyright (c) 1999-2001 Motorola, Inc.
 *
 * This file is part of the SCTP kernel implementation
 *
 * These functions handle output processing.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <[email protected]>
 *
 * Written or modified by:
 *    La Monte H.P. Yarroll <[email protected]>
 *    Karl Knutson          <[email protected]>
 *    Jon Grimm             <[email protected]>
 *    Sridhar Samudrala     <[email protected]>
 */

#define pr_fmt(fmt) …

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/wait.h>
#include <linux/time.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <net/inet_ecn.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/net_namespace.h>

#include <linux/socket.h> /* for sa_family_t */
#include <net/sock.h>

#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
#include <net/sctp/checksum.h>

/* Forward declarations for private helpers. */
static enum sctp_xmit __sctp_packet_append_chunk(struct sctp_packet *packet,
						 struct sctp_chunk *chunk);
static enum sctp_xmit sctp_packet_can_append_data(struct sctp_packet *packet,
						  struct sctp_chunk *chunk);
static void sctp_packet_append_data(struct sctp_packet *packet,
				    struct sctp_chunk *chunk);
static enum sctp_xmit sctp_packet_will_fit(struct sctp_packet *packet,
					   struct sctp_chunk *chunk,
					   u16 chunk_len);

static void sctp_packet_reset(struct sctp_packet *packet)
{ … }

/* Config a packet.
 * This appears to be a followup set of initializations.
 */
void sctp_packet_config(struct sctp_packet *packet, __u32 vtag,
			int ecn_capable)
{ … }

/* Initialize the packet structure. */
void sctp_packet_init(struct sctp_packet *packet,
		      struct sctp_transport *transport,
		      __u16 sport, __u16 dport)
{ … }

/* Free a packet.  */
void sctp_packet_free(struct sctp_packet *packet)
{ … }

/* This routine tries to append the chunk to the offered packet. If adding
 * the chunk causes the packet to exceed the path MTU and COOKIE_ECHO chunk
 * is not present in the packet, it transmits the input packet.
 * Data can be bundled with a packet containing a COOKIE_ECHO chunk as long
 * as it can fit in the packet, but any more data that does not fit in this
 * packet can be sent only after receiving the COOKIE_ACK.
 */
enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
					  struct sctp_chunk *chunk,
					  int one_packet, gfp_t gfp)
{ … }

/* Try to bundle a pad chunk into a packet with a heartbeat chunk for PLPMTUTD probe */
static enum sctp_xmit sctp_packet_bundle_pad(struct sctp_packet *pkt, struct sctp_chunk *chunk)
{ … }

/* Try to bundle an auth chunk into the packet. */
static enum sctp_xmit sctp_packet_bundle_auth(struct sctp_packet *pkt,
					      struct sctp_chunk *chunk)
{ … }

/* Try to bundle a SACK with the packet. */
static enum sctp_xmit sctp_packet_bundle_sack(struct sctp_packet *pkt,
					      struct sctp_chunk *chunk)
{ … }


/* Append a chunk to the offered packet reporting back any inability to do
 * so.
 */
static enum sctp_xmit __sctp_packet_append_chunk(struct sctp_packet *packet,
						 struct sctp_chunk *chunk)
{ … }

/* Append a chunk to the offered packet reporting back any inability to do
 * so.
 */
enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
					struct sctp_chunk *chunk)
{ … }

static void sctp_packet_gso_append(struct sk_buff *head, struct sk_buff *skb)
{ … }

static int sctp_packet_pack(struct sctp_packet *packet,
			    struct sk_buff *head, int gso, gfp_t gfp)
{ … }

/* All packets are sent to the network through this function from
 * sctp_outq_tail().
 *
 * The return value is always 0 for now.
 */
int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp)
{ … }

/********************************************************************
 * 2nd Level Abstractions
 ********************************************************************/

/* This private function check to see if a chunk can be added */
static enum sctp_xmit sctp_packet_can_append_data(struct sctp_packet *packet,
						  struct sctp_chunk *chunk)
{ … }

/* This private function does management things when adding DATA chunk */
static void sctp_packet_append_data(struct sctp_packet *packet,
				struct sctp_chunk *chunk)
{ … }

static enum sctp_xmit sctp_packet_will_fit(struct sctp_packet *packet,
					   struct sctp_chunk *chunk,
					   u16 chunk_len)
{ … }