net/sctp/chunk.c - kernel/msm-4.19 - Gitiles

 /* 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)
 {
 	atomic_set(&msg->refcnt, 1);
 	msg->send_failed = 0;
 	msg->send_error = 0;
 	msg->can_abandon = 0;
 	msg->can_delay = 1;
 	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;
 }

 /* 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);
 }

 /* 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)
 {
 	int max, whole, i, offset, over, err;
 	int len, first_len;
 	int max_data;
 	struct sctp_chunk *chunk;
 	struct sctp_datamsg *msg;
 	struct list_head *pos, *temp;
 	size_t msg_len = iov_iter_count(from);
 	__u8 frag;

 	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 (sinfo->sinfo_timetolive) {
 		/* sinfo_timetolive is in milliseconds */
 		msg->expires_at = jiffies +
 				    msecs_to_jiffies(sinfo->sinfo_timetolive);
 		msg->can_abandon = 1;

 		pr_debug("%s: msg:%p expires_at:%ld jiffies:%ld\n", __func__,
 			 msg, msg->expires_at, jiffies);
 	}

 	/* 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) - sizeof(struct sctp_data_chunk)) & ~3;

 	max = asoc->frag_point;
 	/* 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 -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
 					    hmac_desc->hmac_len);
 	}

 	/* Now, check if we need to reduce our max */
 	if (max > max_data)
 		max = max_data;

 	whole = 0;
 	first_len = max;

 	/* 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)
 		max_data -= WORD_ROUND(sizeof(sctp_sack_chunk_t));

 	/* Encourage Cookie-ECHO bundling. */
 	if (asoc->state < SCTP_STATE_COOKIE_ECHOED)
 		max_data -= SCTP_ARBITRARY_COOKIE_ECHO_LEN;

 	/* Now that we adjusted completely, reset first_len */
 	if (first_len > max_data)
 		first_len = max_data;

 	/* Account for a different sized first fragment */
 	if (msg_len >= first_len) {
 		msg_len -= first_len;
 		whole = 1;
 		msg->can_delay = 0;
 	}

 	/* 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(sock_net(asoc->base.sk), 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;

 			/* 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 = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0);

 		if (!chunk) {
 			err = -ENOMEM;
 			goto errout;
 		}

 		err = sctp_user_addto_chunk(chunk, len, from);
 		if (err < 0)
 			goto errout_chunk_free;

 		/* 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;

 		if ((sinfo->sinfo_flags & SCTP_EOF) ||
 		    (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY))
 			frag |= SCTP_DATA_SACK_IMM;

 		chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0);

 		if (!chunk) {
 			err = -ENOMEM;
 			goto errout;
 		}

 		err = sctp_user_addto_chunk(chunk, over, from);

 		/* 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_chunk_free;

 		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)
 {
 	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;
 }
	/* 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)
	{
	atomic_set(&msg->refcnt, 1);
	msg->send_failed = 0;
	msg->send_error = 0;
	msg->can_abandon = 0;
	msg->can_delay = 1;
	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;
	}

	/* 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);
	}

	/* 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)
	{
	int max, whole, i, offset, over, err;
	int len, first_len;
	int max_data;
	struct sctp_chunk *chunk;
	struct sctp_datamsg *msg;
	struct list_head pos, temp;
	size_t msg_len = iov_iter_count(from);
	__u8 frag;

	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 (sinfo->sinfo_timetolive) {
	/* sinfo_timetolive is in milliseconds */
	msg->expires_at = jiffies +
	msecs_to_jiffies(sinfo->sinfo_timetolive);
	msg->can_abandon = 1;

	pr_debug("%s: msg:%p expires_at:%ld jiffies:%ld\n", __func__,
	msg, msg->expires_at, jiffies);
	}

	/* 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) - sizeof(struct sctp_data_chunk)) & ~3;

	max = asoc->frag_point;
	/* 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 -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
	hmac_desc->hmac_len);
	}

	/* Now, check if we need to reduce our max */
	if (max > max_data)
	max = max_data;

	whole = 0;
	first_len = max;

	/* 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)
	max_data -= WORD_ROUND(sizeof(sctp_sack_chunk_t));

	/* Encourage Cookie-ECHO bundling. */
	if (asoc->state < SCTP_STATE_COOKIE_ECHOED)
	max_data -= SCTP_ARBITRARY_COOKIE_ECHO_LEN;

	/* Now that we adjusted completely, reset first_len */
	if (first_len > max_data)
	first_len = max_data;

	/* Account for a different sized first fragment */
	if (msg_len >= first_len) {
	msg_len -= first_len;
	whole = 1;
	msg->can_delay = 0;
	}

	/* 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(sock_net(asoc->base.sk), 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;

	/* 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 = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0);

	if (!chunk) {
	err = -ENOMEM;
	goto errout;
	}

	err = sctp_user_addto_chunk(chunk, len, from);
	if (err < 0)
	goto errout_chunk_free;

	/* 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;

	if ((sinfo->sinfo_flags & SCTP_EOF) \|\|
	(sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY))
	frag \|= SCTP_DATA_SACK_IMM;

	chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0);

	if (!chunk) {
	err = -ENOMEM;
	goto errout;
	}

	err = sctp_user_addto_chunk(chunk, over, from);

	/* 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_chunk_free;

	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)
	{
	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;
	}