linux/net/sctp/chunk.c
Xin Long 3ff547c06a sctp: add support for SCTP AUTH Information for sendmsg
This patch is to add support for SCTP AUTH Information for sendmsg,
as described in section 5.3.8 of RFC6458.

With this option, you can provide shared key identifier used for
sending the user message.

It's also a necessary send info for sctp_sendv.

Note that it reuses sinfo->sinfo_tsn to indicate if this option is
set and sinfo->sinfo_ssn to save the shkey ID which can be 0.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-03-14 13:48:27 -04:00

369 lines
10 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, see
* <http://www.gnu.org/licenses/>.
*
* Please send any bug reports or fixes you make to the
* email address(es):
* lksctp developers <linux-sctp@vger.kernel.org>
*
* Written or modified by:
* Jon Grimm <jgrimm@us.ibm.com>
* Sridhar Samudrala <sri@us.ibm.com>
*/
#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 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)
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->pathmtu -
sctp_sk(asoc->base.sk)->pf->af->net_header_len -
sizeof(struct sctphdr) - sctp_datachk_len(&asoc->stream);
max_data = SCTP_TRUNC4(max_data);
/* If the 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;
}
}
/* Check what's our max considering the above */
max_data = min_t(size_t, max_data, asoc->frag_point);
/* 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;
SCTP_INC_STATS(sock_net(asoc->base.sk), 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 =
&chunk->asoc->stream.out[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 =
&chunk->asoc->stream.out[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;
}