// 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) KBUILD_MODNAME ": " 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)
{
refcount_set(&msg->refcnt, 1);
msg->send_failed = 0;
msg->send_error = 0;
msg->can_delay = 1;
msg->abandoned = 0;
msg->expires_at = 0;
INIT_LIST_HEAD(&msg->chunks);
}
/* Allocate and initialize datamsg. */
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 sctp_association *asoc = NULL;
struct list_head *pos, *temp;
struct sctp_chunk *chunk;
struct sctp_ulpevent *ev;
int error, sent;
/* Release all references. */
list_for_each_safe(pos, temp, &msg->chunks) {
list_del_init(pos);
chunk = list_entry(pos, struct sctp_chunk, frag_list);
if (!msg->send_failed) {
sctp_chunk_put(chunk);
continue;
}
asoc = chunk->asoc;
error = msg->send_error ?: asoc->outqueue.error;
sent = chunk->has_tsn ? SCTP_DATA_SENT : SCTP_DATA_UNSENT;
if (sctp_ulpevent_type_enabled(asoc->subscribe,
SCTP_SEND_FAILED)) {
ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent,
error, GFP_ATOMIC);
if (ev)
asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
}
if (sctp_ulpevent_type_enabled(asoc->subscribe,
SCTP_SEND_FAILED_EVENT)) {
ev = sctp_ulpevent_make_send_failed_event(asoc, chunk,
sent, error,
GFP_ATOMIC);
if (ev)
asoc->stream.si->enqueue_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)
{
refcount_inc(&msg->refcnt);
}
/* Release a reference. */
void sctp_datamsg_put(struct sctp_datamsg *msg)
{
if (refcount_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 iov_iter *from)
{
size_t len, first_len, max_data, remaining;
size_t msg_len = iov_iter_count(from);
struct sctp_shared_key *shkey = NULL;
struct list_head *pos, *temp;
struct sctp_chunk *chunk;
struct sctp_datamsg *msg;
int err;
msg = sctp_datamsg_new(GFP_KERNEL);
if (!msg)
return ERR_PTR(-ENOMEM);
/* Note: Calculate this outside of the loop, so that all fragments
* have the same expiration.
*/
if (asoc->peer.prsctp_capable && sinfo->sinfo_timetolive &&
(SCTP_PR_TTL_ENABLED(sinfo->sinfo_flags) ||
!SCTP_PR_POLICY(sinfo->sinfo_flags)))
msg->expires_at = jiffies +
msecs_to_jiffies(sinfo->sinfo_timetolive);
/* This is the biggest possible DATA chunk that can fit into
* the packet
*/
max_data = asoc->frag_point;
if (unlikely(!max_data)) {
max_data = sctp_min_frag_point(sctp_sk(asoc->base.sk),
sctp_datachk_len(&asoc->stream));
pr_warn_ratelimited("%s: asoc:%p frag_point is zero, forcing max_data to default minimum (%zu)",
__func__, asoc, max_data);
}
/* If the peer requested that we authenticate DATA chunks
* we need to account 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 -= SCTP_PAD4(sizeof(struct sctp_auth_chunk) +
hmac_desc->hmac_len);
if (sinfo->sinfo_tsn &&
sinfo->sinfo_ssn != asoc->active_key_id) {
shkey = sctp_auth_get_shkey(asoc, sinfo->sinfo_ssn);
if (!shkey) {
err = -EINVAL;
goto errout;
}
} else {
shkey = asoc->shkey;
}
}
/* Set first_len and then account for possible bundles on first frag */
first_len = max_data;
/* 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_data)
first_len -= SCTP_PAD4(sizeof(struct sctp_sack_chunk));
/* Encourage Cookie-ECHO bundling. */
if (asoc->state < SCTP_STATE_COOKIE_ECHOED)
first_len -= SCTP_ARBITRARY_COOKIE_ECHO_LEN;
/* Account for a different sized first fragment */
if (msg_len >= first_len) {
msg->can_delay = 0;
if (msg_len > first_len)
SCTP_INC_STATS(asoc->base.net,
SCTP_MIB_FRAGUSRMSGS);
} else {
/* Which may be the only one... */
first_len = msg_len;
}
/* Create chunks for all DATA chunks. */
for (remaining = msg_len; remaining; remaining -= len) {
u8 frag = SCTP_DATA_MIDDLE_FRAG;
if (remaining == msg_len) {
/* First frag, which may also be the last */
frag |= SCTP_DATA_FIRST_FRAG;
len = first_len;
} else {
/* Middle frags */
len = max_data;
}
if (len >= remaining) {
/* Last frag, which may also be the first */
len = remaining;
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 = asoc->stream.si->make_datafrag(asoc, sinfo, len, frag,
GFP_KERNEL);
if (!chunk) {
err = -ENOMEM;
goto errout;
}
err = sctp_user_addto_chunk(chunk, len, from);
if (err < 0)
goto errout_chunk_free;
chunk->shkey = shkey;
/* Put the chunk->skb back into the form expected by send. */
__skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr -
chunk->skb->data);
sctp_datamsg_assign(msg, chunk);
list_add_tail(&chunk->frag_list, &msg->chunks);
}
return msg;
errout_chunk_free:
sctp_chunk_free(chunk);
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 ERR_PTR(err);
}
/* Check whether this message has expired. */
int sctp_chunk_abandoned(struct sctp_chunk *chunk)
{
if (!chunk->asoc->peer.prsctp_capable)
return 0;
if (chunk->msg->abandoned)
return 1;
if (!chunk->has_tsn &&
!(chunk->chunk_hdr->flags & SCTP_DATA_FIRST_FRAG))
return 0;
if (SCTP_PR_TTL_ENABLED(chunk->sinfo.sinfo_flags) &&
time_after(jiffies, chunk->msg->expires_at)) {
struct sctp_stream_out *streamout =
SCTP_SO(&chunk->asoc->stream,
chunk->sinfo.sinfo_stream);
if (chunk->sent_count) {
chunk->asoc->abandoned_sent[SCTP_PR_INDEX(TTL)]++;
streamout->ext->abandoned_sent[SCTP_PR_INDEX(TTL)]++;
} else {
chunk->asoc->abandoned_unsent[SCTP_PR_INDEX(TTL)]++;
streamout->ext->abandoned_unsent[SCTP_PR_INDEX(TTL)]++;
}
chunk->msg->abandoned = 1;
return 1;
} else if (SCTP_PR_RTX_ENABLED(chunk->sinfo.sinfo_flags) &&
chunk->sent_count > chunk->sinfo.sinfo_timetolive) {
struct sctp_stream_out *streamout =
SCTP_SO(&chunk->asoc->stream,
chunk->sinfo.sinfo_stream);
chunk->asoc->abandoned_sent[SCTP_PR_INDEX(RTX)]++;
streamout->ext->abandoned_sent[SCTP_PR_INDEX(RTX)]++;
chunk->msg->abandoned = 1;
return 1;
} else if (!SCTP_PR_POLICY(chunk->sinfo.sinfo_flags) &&
chunk->msg->expires_at &&
time_after(jiffies, chunk->msg->expires_at)) {
chunk->msg->abandoned = 1;
return 1;
}
/* PRIO policy is processed by sendmsg, not here */
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;
}
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