[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / dccp / ackvec.c

/*
 *  net/dccp/ackvec.c
 *
 *  An implementation of the DCCP protocol
 *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
 *
 *      This program 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; version 2 of the License;
 */

#include "ackvec.h"
#include "dccp.h"

#include <linux/dccp.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/slab.h>

#include <net/sock.h>

static struct kmem_cache *dccp_ackvec_slab;
static struct kmem_cache *dccp_ackvec_record_slab;

static struct dccp_ackvec_record *dccp_ackvec_record_new(void)
{
	struct dccp_ackvec_record *avr =
			kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC);

	if (avr != NULL)
		INIT_LIST_HEAD(&avr->dccpavr_node);

	return avr;
}

static void dccp_ackvec_record_delete(struct dccp_ackvec_record *avr)
{
	if (unlikely(avr == NULL))
		return;
	/* Check if deleting a linked record */
	WARN_ON(!list_empty(&avr->dccpavr_node));
	kmem_cache_free(dccp_ackvec_record_slab, avr);
}

static void dccp_ackvec_insert_avr(struct dccp_ackvec *av,
				   struct dccp_ackvec_record *avr)
{
	/*
	 * AVRs are sorted by seqno. Since we are sending them in order, we
	 * just add the AVR at the head of the list.
	 * -sorbo.
	 */
	if (!list_empty(&av->dccpav_records)) {
		const struct dccp_ackvec_record *head =
					list_entry(av->dccpav_records.next,
						   struct dccp_ackvec_record,
						   dccpavr_node);
		BUG_ON(before48(avr->dccpavr_ack_seqno,
				head->dccpavr_ack_seqno));
	}

	list_add(&avr->dccpavr_node, &av->dccpav_records);
}

int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
{
	struct dccp_sock *dp = dccp_sk(sk);
	struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec;
	/* Figure out how many options do we need to represent the ackvec */
	const u16 nr_opts = DIV_ROUND_UP(av->dccpav_vec_len,
					 DCCP_MAX_ACKVEC_OPT_LEN);
	u16 len = av->dccpav_vec_len + 2 * nr_opts, i;
	u32 elapsed_time;
	const unsigned char *tail, *from;
	unsigned char *to;
	struct dccp_ackvec_record *avr;
	suseconds_t delta;

	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
		return -1;

	delta = ktime_us_delta(ktime_get_real(), av->dccpav_time);
	elapsed_time = delta / 10;

	if (elapsed_time != 0 &&
	    dccp_insert_option_elapsed_time(sk, skb, elapsed_time))
		return -1;

	avr = dccp_ackvec_record_new();
	if (avr == NULL)
		return -1;

	DCCP_SKB_CB(skb)->dccpd_opt_len += len;

	to   = skb_push(skb, len);
	len  = av->dccpav_vec_len;
	from = av->dccpav_buf + av->dccpav_buf_head;
	tail = av->dccpav_buf + DCCP_MAX_ACKVEC_LEN;

	for (i = 0; i < nr_opts; ++i) {
		int copylen = len;

		if (len > DCCP_MAX_ACKVEC_OPT_LEN)
			copylen = DCCP_MAX_ACKVEC_OPT_LEN;

		*to++ = DCCPO_ACK_VECTOR_0;
		*to++ = copylen + 2;

		/* Check if buf_head wraps */
		if (from + copylen > tail) {
			const u16 tailsize = tail - from;

			memcpy(to, from, tailsize);
			to	+= tailsize;
			len	-= tailsize;
			copylen	-= tailsize;
			from	= av->dccpav_buf;
		}

		memcpy(to, from, copylen);
		from += copylen;
		to   += copylen;
		len  -= copylen;
	}

	/*
	 *	From RFC 4340, A.2:
	 *
	 *	For each acknowledgement it sends, the HC-Receiver will add an
	 *	acknowledgement record.  ack_seqno will equal the HC-Receiver
	 *	sequence number it used for the ack packet; ack_ptr will equal
	 *	buf_head; ack_ackno will equal buf_ackno; and ack_nonce will
	 *	equal buf_nonce.
	 */
	avr->dccpavr_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
	avr->dccpavr_ack_ptr   = av->dccpav_buf_head;
	avr->dccpavr_ack_ackno = av->dccpav_buf_ackno;
	avr->dccpavr_ack_nonce = av->dccpav_buf_nonce;
	avr->dccpavr_sent_len  = av->dccpav_vec_len;

	dccp_ackvec_insert_avr(av, avr);

	dccp_pr_debug("%s ACK Vector 0, len=%d, ack_seqno=%llu, "
		      "ack_ackno=%llu\n",
		      dccp_role(sk), avr->dccpavr_sent_len,
		      (unsigned long long)avr->dccpavr_ack_seqno,
		      (unsigned long long)avr->dccpavr_ack_ackno);
	return 0;
}

struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
{
	struct dccp_ackvec *av = kmem_cache_alloc(dccp_ackvec_slab, priority);

	if (av != NULL) {
		av->dccpav_buf_head	= DCCP_MAX_ACKVEC_LEN - 1;
		av->dccpav_buf_ackno	= UINT48_MAX + 1;
		av->dccpav_buf_nonce = av->dccpav_buf_nonce = 0;
		av->dccpav_time	     = ktime_set(0, 0);
		av->dccpav_vec_len	= 0;
		INIT_LIST_HEAD(&av->dccpav_records);
	}

	return av;
}

void dccp_ackvec_free(struct dccp_ackvec *av)
{
	if (unlikely(av == NULL))
		return;

	if (!list_empty(&av->dccpav_records)) {
		struct dccp_ackvec_record *avr, *next;

		list_for_each_entry_safe(avr, next, &av->dccpav_records,
					 dccpavr_node) {
			list_del_init(&avr->dccpavr_node);
			dccp_ackvec_record_delete(avr);
		}
	}

	kmem_cache_free(dccp_ackvec_slab, av);
}

static inline u8 dccp_ackvec_state(const struct dccp_ackvec *av,
				   const u32 index)
{
	return av->dccpav_buf[index] & DCCP_ACKVEC_STATE_MASK;
}

static inline u8 dccp_ackvec_len(const struct dccp_ackvec *av,
				 const u32 index)
{
	return av->dccpav_buf[index] & DCCP_ACKVEC_LEN_MASK;
}

/*
 * If several packets are missing, the HC-Receiver may prefer to enter multiple
 * bytes with run length 0, rather than a single byte with a larger run length;
 * this simplifies table updates if one of the missing packets arrives.
 */
static inline int dccp_ackvec_set_buf_head_state(struct dccp_ackvec *av,
						 const unsigned int packets,
						 const unsigned char state)
{
	unsigned int gap;
	long new_head;

	if (av->dccpav_vec_len + packets > DCCP_MAX_ACKVEC_LEN)
		return -ENOBUFS;

	gap	 = packets - 1;
	new_head = av->dccpav_buf_head - packets;

	if (new_head < 0) {
		if (gap > 0) {
			memset(av->dccpav_buf, DCCP_ACKVEC_STATE_NOT_RECEIVED,
			       gap + new_head + 1);
			gap = -new_head;
		}
		new_head += DCCP_MAX_ACKVEC_LEN;
	}

	av->dccpav_buf_head = new_head;

	if (gap > 0)
		memset(av->dccpav_buf + av->dccpav_buf_head + 1,
		       DCCP_ACKVEC_STATE_NOT_RECEIVED, gap);

	av->dccpav_buf[av->dccpav_buf_head] = state;
	av->dccpav_vec_len += packets;
	return 0;
}

/*
 * Implements the RFC 4340, Appendix A
 */
int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
		    const u64 ackno, const u8 state)
{
	/*
	 * Check at the right places if the buffer is full, if it is, tell the
	 * caller to start dropping packets till the HC-Sender acks our ACK
	 * vectors, when we will free up space in dccpav_buf.
	 *
	 * We may well decide to do buffer compression, etc, but for now lets
	 * just drop.
	 *
	 * From Appendix A.1.1 (`New Packets'):
	 *
	 *	Of course, the circular buffer may overflow, either when the
	 *	HC-Sender is sending data at a very high rate, when the
	 *	HC-Receiver's acknowledgements are not reaching the HC-Sender,
	 *	or when the HC-Sender is forgetting to acknowledge those acks
	 *	(so the HC-Receiver is unable to clean up old state). In this
	 *	case, the HC-Receiver should either compress the buffer (by
	 *	increasing run lengths when possible), transfer its state to
	 *	a larger buffer, or, as a last resort, drop all received
	 *	packets, without processing them whatsoever, until its buffer
	 *	shrinks again.
	 */

	/* See if this is the first ackno being inserted */
	if (av->dccpav_vec_len == 0) {
		av->dccpav_buf[av->dccpav_buf_head] = state;
		av->dccpav_vec_len = 1;
	} else if (after48(ackno, av->dccpav_buf_ackno)) {
		const u64 delta = dccp_delta_seqno(av->dccpav_buf_ackno,
						   ackno);

		/*
		 * Look if the state of this packet is the same as the
		 * previous ackno and if so if we can bump the head len.
		 */
		if (delta == 1 &&
		    dccp_ackvec_state(av, av->dccpav_buf_head) == state &&
		    (dccp_ackvec_len(av, av->dccpav_buf_head) <
		     DCCP_ACKVEC_LEN_MASK))
			av->dccpav_buf[av->dccpav_buf_head]++;
		else if (dccp_ackvec_set_buf_head_state(av, delta, state))
			return -ENOBUFS;
	} else {
		/*
		 * A.1.2.  Old Packets
		 *
		 *	When a packet with Sequence Number S <= buf_ackno
		 *	arrives, the HC-Receiver will scan the table for
		 *	the byte corresponding to S. (Indexing structures
		 *	could reduce the complexity of this scan.)
		 */
		u64 delta = dccp_delta_seqno(ackno, av->dccpav_buf_ackno);
		u32 index = av->dccpav_buf_head;

		while (1) {
			const u8 len = dccp_ackvec_len(av, index);
			const u8 state = dccp_ackvec_state(av, index);
			/*
			 * valid packets not yet in dccpav_buf have a reserved
			 * entry, with a len equal to 0.
			 */
			if (state == DCCP_ACKVEC_STATE_NOT_RECEIVED &&
			    len == 0 && delta == 0) { /* Found our
							 reserved seat! */
				dccp_pr_debug("Found %llu reserved seat!\n",
					      (unsigned long long)ackno);
				av->dccpav_buf[index] = state;
				goto out;
			}
			/* len == 0 means one packet */
			if (delta < len + 1)
				goto out_duplicate;

			delta -= len + 1;
			if (++index == DCCP_MAX_ACKVEC_LEN)
				index = 0;
		}
	}

	av->dccpav_buf_ackno = ackno;
	av->dccpav_time = ktime_get_real();
out:
	return 0;

out_duplicate:
	/* Duplicate packet */
	dccp_pr_debug("Received a dup or already considered lost "
		      "packet: %llu\n", (unsigned long long)ackno);
	return -EILSEQ;
}

#ifdef CONFIG_IP_DCCP_DEBUG
void dccp_ackvector_print(const u64 ackno, const unsigned char *vector, int len)
{
	dccp_pr_debug_cat("ACK vector len=%d, ackno=%llu |", len,
			 (unsigned long long)ackno);

	while (len--) {
		const u8 state = (*vector & DCCP_ACKVEC_STATE_MASK) >> 6;
		const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;

		dccp_pr_debug_cat("%d,%d|", state, rl);
		++vector;
	}

	dccp_pr_debug_cat("\n");
}

void dccp_ackvec_print(const struct dccp_ackvec *av)
{
	dccp_ackvector_print(av->dccpav_buf_ackno,
			     av->dccpav_buf + av->dccpav_buf_head,
			     av->dccpav_vec_len);
}
#endif

static void dccp_ackvec_throw_record(struct dccp_ackvec *av,
				     struct dccp_ackvec_record *avr)
{
	struct dccp_ackvec_record *next;

	/* sort out vector length */
	if (av->dccpav_buf_head <= avr->dccpavr_ack_ptr)
		av->dccpav_vec_len = avr->dccpavr_ack_ptr - av->dccpav_buf_head;
	else
		av->dccpav_vec_len = DCCP_MAX_ACKVEC_LEN - 1
				     - av->dccpav_buf_head
				     + avr->dccpavr_ack_ptr;

	/* free records */
	list_for_each_entry_safe_from(avr, next, &av->dccpav_records,
				      dccpavr_node) {
		list_del_init(&avr->dccpavr_node);
		dccp_ackvec_record_delete(avr);
	}
}

void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, struct sock *sk,
				 const u64 ackno)
{
	struct dccp_ackvec_record *avr;

	/*
	 * If we traverse backwards, it should be faster when we have large
	 * windows. We will be receiving ACKs for stuff we sent a while back
	 * -sorbo.
	 */
	list_for_each_entry_reverse(avr, &av->dccpav_records, dccpavr_node) {
		if (ackno == avr->dccpavr_ack_seqno) {
			dccp_pr_debug("%s ACK packet 0, len=%d, ack_seqno=%llu, "
				      "ack_ackno=%llu, ACKED!\n",
				      dccp_role(sk), 1,
				      (unsigned long long)avr->dccpavr_ack_seqno,
				      (unsigned long long)avr->dccpavr_ack_ackno);
			dccp_ackvec_throw_record(av, avr);
			break;
		} else if (avr->dccpavr_ack_seqno > ackno)
			break; /* old news */
	}
}

static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
					    struct sock *sk, u64 *ackno,
					    const unsigned char len,
					    const unsigned char *vector)
{
	unsigned char i;
	struct dccp_ackvec_record *avr;

	/* Check if we actually sent an ACK vector */
	if (list_empty(&av->dccpav_records))
		return;

	i = len;
	/*
	 * XXX
	 * I think it might be more efficient to work backwards. See comment on
	 * rcv_ackno. -sorbo.
	 */
	avr = list_entry(av->dccpav_records.next, struct dccp_ackvec_record,
			 dccpavr_node);
	while (i--) {
		const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
		u64 ackno_end_rl;

		dccp_set_seqno(&ackno_end_rl, *ackno - rl);

		/*
		 * If our AVR sequence number is greater than the ack, go
		 * forward in the AVR list until it is not so.
		 */
		list_for_each_entry_from(avr, &av->dccpav_records,
					 dccpavr_node) {
			if (!after48(avr->dccpavr_ack_seqno, *ackno))
				goto found;
		}
		/* End of the dccpav_records list, not found, exit */
		break;
found:
		if (between48(avr->dccpavr_ack_seqno, ackno_end_rl, *ackno)) {
			const u8 state = *vector & DCCP_ACKVEC_STATE_MASK;
			if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED) {
				dccp_pr_debug("%s ACK vector 0, len=%d, "
					      "ack_seqno=%llu, ack_ackno=%llu, "
					      "ACKED!\n",
					      dccp_role(sk), len,
					      (unsigned long long)
					      avr->dccpavr_ack_seqno,
					      (unsigned long long)
					      avr->dccpavr_ack_ackno);
				dccp_ackvec_throw_record(av, avr);
				break;
			}
			/*
			 * If it wasn't received, continue scanning... we might
			 * find another one.
			 */
		}

		dccp_set_seqno(ackno, ackno_end_rl - 1);
		++vector;
	}
}

int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
		      u64 *ackno, const u8 opt, const u8 *value, const u8 len)
{
	if (len > DCCP_MAX_ACKVEC_OPT_LEN)
		return -1;

	/* dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq, value, len); */
	dccp_ackvec_check_rcv_ackvector(dccp_sk(sk)->dccps_hc_rx_ackvec, sk,
					ackno, len, value);
	return 0;
}

int __init dccp_ackvec_init(void)
{
	dccp_ackvec_slab = kmem_cache_create("dccp_ackvec",
					     sizeof(struct dccp_ackvec), 0,
					     SLAB_HWCACHE_ALIGN, NULL);
	if (dccp_ackvec_slab == NULL)
		goto out_err;

	dccp_ackvec_record_slab =
			kmem_cache_create("dccp_ackvec_record",
					  sizeof(struct dccp_ackvec_record),
					  0, SLAB_HWCACHE_ALIGN, NULL);
	if (dccp_ackvec_record_slab == NULL)
		goto out_destroy_slab;

	return 0;

out_destroy_slab:
	kmem_cache_destroy(dccp_ackvec_slab);
	dccp_ackvec_slab = NULL;
out_err:
	DCCP_CRIT("Unable to create Ack Vector slab cache");
	return -ENOBUFS;
}

void dccp_ackvec_exit(void)
{
	if (dccp_ackvec_slab != NULL) {
		kmem_cache_destroy(dccp_ackvec_slab);
		dccp_ackvec_slab = NULL;
	}
	if (dccp_ackvec_record_slab != NULL) {
		kmem_cache_destroy(dccp_ackvec_record_slab);
		dccp_ackvec_record_slab = NULL;
	}
}
Commit	Line	Data
ae31c339 ACM	1	/*
	2	* net/dccp/ackvec.c
	3	*
	4	* An implementation of the DCCP protocol
	5	* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
	6	*
	7	* This program is free software; you can redistribute it and/or modify it
	8	* under the terms of the GNU General Public License as published by the
	9	* Free Software Foundation; version 2 of the License;
	10	*/
	11
	12	#include "ackvec.h"
	13	#include "dccp.h"
	14
	15	#include <linux/dccp.h>
9b07ef5d ACM	16	#include <linux/init.h>
	17	#include <linux/errno.h>
	18	#include <linux/kernel.h>
ae31c339	19	#include <linux/skbuff.h>
9b07ef5d	20	#include <linux/slab.h>
ae31c339 ACM	21
	22	#include <net/sock.h>
	23
e18b890b CL	24	static struct kmem_cache *dccp_ackvec_slab;
e18b890b CL	25	static struct kmem_cache *dccp_ackvec_record_slab;
02bcf28c AB	26
	27	static struct dccp_ackvec_record *dccp_ackvec_record_new(void)
	28	{
	29	struct dccp_ackvec_record *avr =
	30	kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC);
	31
	32	if (avr != NULL)
	33	INIT_LIST_HEAD(&avr->dccpavr_node);
	34
	35	return avr;
	36	}
	37
	38	static void dccp_ackvec_record_delete(struct dccp_ackvec_record *avr)
	39	{
	40	if (unlikely(avr == NULL))
	41	return;
	42	/* Check if deleting a linked record */
	43	WARN_ON(!list_empty(&avr->dccpavr_node));
	44	kmem_cache_free(dccp_ackvec_record_slab, avr);
	45	}
	46
	47	static void dccp_ackvec_insert_avr(struct dccp_ackvec *av,
	48	struct dccp_ackvec_record *avr)
	49	{
	50	/*
	51	* AVRs are sorted by seqno. Since we are sending them in order, we
	52	* just add the AVR at the head of the list.
	53	* -sorbo.
	54	*/
	55	if (!list_empty(&av->dccpav_records)) {
	56	const struct dccp_ackvec_record *head =
	57	list_entry(av->dccpav_records.next,
	58	struct dccp_ackvec_record,
	59	dccpavr_node);
	60	BUG_ON(before48(avr->dccpavr_ack_seqno,
	61	head->dccpavr_ack_seqno));
	62	}
	63
	64	list_add(&avr->dccpavr_node, &av->dccpav_records);
	65	}
9b07ef5d	66
ae31c339 ACM	67	int dccp_insert_option_ackvec(struct sock sk, struct sk_buff skb)
	68	{
	69	struct dccp_sock *dp = dccp_sk(sk);
	70	struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec;
522f1d09	71	/* Figure out how many options do we need to represent the ackvec */
172589cc IJ	72	const u16 nr_opts = DIV_ROUND_UP(av->dccpav_vec_len,
172589cc IJ	73	DCCP_MAX_ACKVEC_OPT_LEN);
522f1d09	74	u16 len = av->dccpav_vec_len + 2 * nr_opts, i;
ae31c339	75	u32 elapsed_time;
522f1d09 AB	76	const unsigned char tail, from;
522f1d09 AB	77	unsigned char *to;
02bcf28c	78	struct dccp_ackvec_record *avr;
b8bda9d7	79	suseconds_t delta;
02bcf28c AB	80
	81	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
	82	return -1;
	83
b8bda9d7 ACM	84	delta = ktime_us_delta(ktime_get_real(), av->dccpav_time);
b8bda9d7 ACM	85	elapsed_time = delta / 10;
ae31c339	86
2d0817d1 ACM	87	if (elapsed_time != 0 &&
	88	dccp_insert_option_elapsed_time(sk, skb, elapsed_time))
	89	return -1;
	90
	91	avr = dccp_ackvec_record_new();
	92	if (avr == NULL)
	93	return -1;
ae31c339	94
ae31c339 ACM	95	DCCP_SKB_CB(skb)->dccpd_opt_len += len;
ae31c339 ACM	96
522f1d09	97	to = skb_push(skb, len);
ae31c339 ACM	98	len = av->dccpav_vec_len;
ae31c339 ACM	99	from = av->dccpav_buf + av->dccpav_buf_head;
522f1d09 AB	100	tail = av->dccpav_buf + DCCP_MAX_ACKVEC_LEN;
	101
	102	for (i = 0; i < nr_opts; ++i) {
	103	int copylen = len;
	104
	105	if (len > DCCP_MAX_ACKVEC_OPT_LEN)
	106	copylen = DCCP_MAX_ACKVEC_OPT_LEN;
	107
	108	*to++ = DCCPO_ACK_VECTOR_0;
	109	*to++ = copylen + 2;
	110
	111	/* Check if buf_head wraps */
	112	if (from + copylen > tail) {
	113	const u16 tailsize = tail - from;
ae31c339	114
522f1d09 AB	115	memcpy(to, from, tailsize);
	116	to += tailsize;
	117	len -= tailsize;
	118	copylen -= tailsize;
	119	from = av->dccpav_buf;
	120	}
ae31c339	121
522f1d09 AB	122	memcpy(to, from, copylen);
	123	from += copylen;
	124	to += copylen;
	125	len -= copylen;
ae31c339 ACM	126	}
ae31c339 ACM	127
ae31c339	128	/*
0e64e94e	129	* From RFC 4340, A.2:
ae31c339 ACM	130	*
	131	* For each acknowledgement it sends, the HC-Receiver will add an
	132	* acknowledgement record. ack_seqno will equal the HC-Receiver
	133	* sequence number it used for the ack packet; ack_ptr will equal
	134	* buf_head; ack_ackno will equal buf_ackno; and ack_nonce will
	135	* equal buf_nonce.
ae31c339	136	*/
02bcf28c AB	137	avr->dccpavr_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
	138	avr->dccpavr_ack_ptr = av->dccpav_buf_head;
	139	avr->dccpavr_ack_ackno = av->dccpav_buf_ackno;
	140	avr->dccpavr_ack_nonce = av->dccpav_buf_nonce;
	141	avr->dccpavr_sent_len = av->dccpav_vec_len;
	142
	143	dccp_ackvec_insert_avr(av, avr);
ae31c339	144
09dbc389	145	dccp_pr_debug("%s ACK Vector 0, len=%d, ack_seqno=%llu, "
ae31c339	146	"ack_ackno=%llu\n",
09dbc389	147	dccp_role(sk), avr->dccpavr_sent_len,
02bcf28c AB	148	(unsigned long long)avr->dccpavr_ack_seqno,
	149	(unsigned long long)avr->dccpavr_ack_ackno);
	150	return 0;
ae31c339 ACM	151	}
ae31c339 ACM	152
7400d781	153	struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
ae31c339	154	{
9b07ef5d	155	struct dccp_ackvec *av = kmem_cache_alloc(dccp_ackvec_slab, priority);
e4dfd449	156
ae31c339	157	if (av != NULL) {
4a0a50fb	158	av->dccpav_buf_head = DCCP_MAX_ACKVEC_LEN - 1;
6b811d43	159	av->dccpav_buf_ackno = UINT48_MAX + 1;
ae31c339	160	av->dccpav_buf_nonce = av->dccpav_buf_nonce = 0;
b8bda9d7	161	av->dccpav_time = ktime_set(0, 0);
4a0a50fb	162	av->dccpav_vec_len = 0;
02bcf28c	163	INIT_LIST_HEAD(&av->dccpav_records);
ae31c339 ACM	164	}
	165
	166	return av;
	167	}
	168
	169	void dccp_ackvec_free(struct dccp_ackvec *av)
	170	{
02bcf28c AB	171	if (unlikely(av == NULL))
02bcf28c AB	172	return;
d5e9b2c7 ACM	173
	174	if (!list_empty(&av->dccpav_records)) {
	175	struct dccp_ackvec_record avr, next;
	176
	177	list_for_each_entry_safe(avr, next, &av->dccpav_records,
	178	dccpavr_node) {
	179	list_del_init(&avr->dccpavr_node);
	180	dccp_ackvec_record_delete(avr);
	181	}
	182	}
	183
9b07ef5d	184	kmem_cache_free(dccp_ackvec_slab, av);
ae31c339 ACM	185	}
	186
	187	static inline u8 dccp_ackvec_state(const struct dccp_ackvec *av,
bdf13d20	188	const u32 index)
ae31c339 ACM	189	{
	190	return av->dccpav_buf[index] & DCCP_ACKVEC_STATE_MASK;
	191	}
	192
	193	static inline u8 dccp_ackvec_len(const struct dccp_ackvec *av,
bdf13d20	194	const u32 index)
ae31c339 ACM	195	{
	196	return av->dccpav_buf[index] & DCCP_ACKVEC_LEN_MASK;
	197	}
	198
	199	/*
	200	* If several packets are missing, the HC-Receiver may prefer to enter multiple
	201	* bytes with run length 0, rather than a single byte with a larger run length;
	202	* this simplifies table updates if one of the missing packets arrives.
	203	*/
	204	static inline int dccp_ackvec_set_buf_head_state(struct dccp_ackvec *av,
	205	const unsigned int packets,
e4dfd449	206	const unsigned char state)
ae31c339 ACM	207	{
ae31c339 ACM	208	unsigned int gap;
a8fc3d8d	209	long new_head;
ae31c339	210
7400d781	211	if (av->dccpav_vec_len + packets > DCCP_MAX_ACKVEC_LEN)
ae31c339 ACM	212	return -ENOBUFS;
	213
	214	gap = packets - 1;
	215	new_head = av->dccpav_buf_head - packets;
	216
	217	if (new_head < 0) {
	218	if (gap > 0) {
	219	memset(av->dccpav_buf, DCCP_ACKVEC_STATE_NOT_RECEIVED,
	220	gap + new_head + 1);
	221	gap = -new_head;
	222	}
7400d781	223	new_head += DCCP_MAX_ACKVEC_LEN;
8109b02b	224	}
ae31c339 ACM	225
	226	av->dccpav_buf_head = new_head;
	227
	228	if (gap > 0)
	229	memset(av->dccpav_buf + av->dccpav_buf_head + 1,
	230	DCCP_ACKVEC_STATE_NOT_RECEIVED, gap);
	231
	232	av->dccpav_buf[av->dccpav_buf_head] = state;
	233	av->dccpav_vec_len += packets;
	234	return 0;
	235	}
	236
	237	/*
0e64e94e	238	* Implements the RFC 4340, Appendix A
ae31c339 ACM	239	*/
	240	int dccp_ackvec_add(struct dccp_ackvec av, const struct sock sk,
	241	const u64 ackno, const u8 state)
	242	{
	243	/*
	244	* Check at the right places if the buffer is full, if it is, tell the
	245	* caller to start dropping packets till the HC-Sender acks our ACK
	246	* vectors, when we will free up space in dccpav_buf.
	247	*
	248	* We may well decide to do buffer compression, etc, but for now lets
	249	* just drop.
	250	*
0e64e94e	251	* From Appendix A.1.1 (`New Packets'):
ae31c339 ACM	252	*
	253	* Of course, the circular buffer may overflow, either when the
	254	* HC-Sender is sending data at a very high rate, when the
	255	* HC-Receiver's acknowledgements are not reaching the HC-Sender,
	256	* or when the HC-Sender is forgetting to acknowledge those acks
	257	* (so the HC-Receiver is unable to clean up old state). In this
	258	* case, the HC-Receiver should either compress the buffer (by
	259	* increasing run lengths when possible), transfer its state to
	260	* a larger buffer, or, as a last resort, drop all received
	261	* packets, without processing them whatsoever, until its buffer
	262	* shrinks again.
	263	*/
	264
	265	/* See if this is the first ackno being inserted */
	266	if (av->dccpav_vec_len == 0) {
	267	av->dccpav_buf[av->dccpav_buf_head] = state;
	268	av->dccpav_vec_len = 1;
	269	} else if (after48(ackno, av->dccpav_buf_ackno)) {
	270	const u64 delta = dccp_delta_seqno(av->dccpav_buf_ackno,
	271	ackno);
	272
	273	/*
	274	* Look if the state of this packet is the same as the
	275	* previous ackno and if so if we can bump the head len.
	276	*/
	277	if (delta == 1 &&
	278	dccp_ackvec_state(av, av->dccpav_buf_head) == state &&
	279	(dccp_ackvec_len(av, av->dccpav_buf_head) <
	280	DCCP_ACKVEC_LEN_MASK))
	281	av->dccpav_buf[av->dccpav_buf_head]++;
	282	else if (dccp_ackvec_set_buf_head_state(av, delta, state))
	283	return -ENOBUFS;
	284	} else {
	285	/*
	286	* A.1.2. Old Packets
	287	*
0e64e94e GR	288	* When a packet with Sequence Number S <= buf_ackno
	289	* arrives, the HC-Receiver will scan the table for
	290	* the byte corresponding to S. (Indexing structures
ae31c339 ACM	291	* could reduce the complexity of this scan.)
	292	*/
	293	u64 delta = dccp_delta_seqno(ackno, av->dccpav_buf_ackno);
bdf13d20	294	u32 index = av->dccpav_buf_head;
ae31c339 ACM	295
	296	while (1) {
	297	const u8 len = dccp_ackvec_len(av, index);
	298	const u8 state = dccp_ackvec_state(av, index);
	299	/*
	300	* valid packets not yet in dccpav_buf have a reserved
	301	* entry, with a len equal to 0.
	302	*/
	303	if (state == DCCP_ACKVEC_STATE_NOT_RECEIVED &&
	304	len == 0 && delta == 0) { /* Found our
	305	reserved seat! */
	306	dccp_pr_debug("Found %llu reserved seat!\n",
	307	(unsigned long long)ackno);
	308	av->dccpav_buf[index] = state;
	309	goto out;
	310	}
	311	/* len == 0 means one packet */
	312	if (delta < len + 1)
	313	goto out_duplicate;
	314
	315	delta -= len + 1;
7400d781	316	if (++index == DCCP_MAX_ACKVEC_LEN)
ae31c339 ACM	317	index = 0;
	318	}
	319	}
	320
	321	av->dccpav_buf_ackno = ackno;
b8bda9d7	322	av->dccpav_time = ktime_get_real();
ae31c339	323	out:
ae31c339 ACM	324	return 0;
	325
	326	out_duplicate:
	327	/* Duplicate packet */
	328	dccp_pr_debug("Received a dup or already considered lost "
	329	"packet: %llu\n", (unsigned long long)ackno);
	330	return -EILSEQ;
	331	}
	332
	333	#ifdef CONFIG_IP_DCCP_DEBUG
	334	void dccp_ackvector_print(const u64 ackno, const unsigned char *vector, int len)
	335	{
84116716	336	dccp_pr_debug_cat("ACK vector len=%d, ackno=%llu \|", len,
8109b02b	337	(unsigned long long)ackno);
ae31c339 ACM	338
	339	while (len--) {
	340	const u8 state = (*vector & DCCP_ACKVEC_STATE_MASK) >> 6;
	341	const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
	342
84116716	343	dccp_pr_debug_cat("%d,%d\|", state, rl);
ae31c339 ACM	344	++vector;
	345	}
	346
84116716	347	dccp_pr_debug_cat("\n");
ae31c339 ACM	348	}
	349
	350	void dccp_ackvec_print(const struct dccp_ackvec *av)
	351	{
	352	dccp_ackvector_print(av->dccpav_buf_ackno,
	353	av->dccpav_buf + av->dccpav_buf_head,
	354	av->dccpav_vec_len);
	355	}
	356	#endif
	357
02bcf28c AB	358	static void dccp_ackvec_throw_record(struct dccp_ackvec *av,
02bcf28c AB	359	struct dccp_ackvec_record *avr)
ae31c339	360	{
02bcf28c AB	361	struct dccp_ackvec_record *next;
02bcf28c AB	362
23d06e3b AB	363	/* sort out vector length */
	364	if (av->dccpav_buf_head <= avr->dccpavr_ack_ptr)
	365	av->dccpav_vec_len = avr->dccpavr_ack_ptr - av->dccpav_buf_head;
	366	else
	367	av->dccpav_vec_len = DCCP_MAX_ACKVEC_LEN - 1
	368	- av->dccpav_buf_head
	369	+ avr->dccpavr_ack_ptr;
02bcf28c AB	370
	371	/* free records */
	372	list_for_each_entry_safe_from(avr, next, &av->dccpav_records,
	373	dccpavr_node) {
	374	list_del_init(&avr->dccpavr_node);
	375	dccp_ackvec_record_delete(avr);
	376	}
ae31c339 ACM	377	}
	378
	379	void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec av, struct sock sk,
	380	const u64 ackno)
	381	{
02bcf28c	382	struct dccp_ackvec_record *avr;
ae31c339	383
02bcf28c AB	384	/*
	385	* If we traverse backwards, it should be faster when we have large
	386	* windows. We will be receiving ACKs for stuff we sent a while back
	387	* -sorbo.
	388	*/
	389	list_for_each_entry_reverse(avr, &av->dccpav_records, dccpavr_node) {
	390	if (ackno == avr->dccpavr_ack_seqno) {
09dbc389	391	dccp_pr_debug("%s ACK packet 0, len=%d, ack_seqno=%llu, "
02bcf28c	392	"ack_ackno=%llu, ACKED!\n",
09dbc389	393	dccp_role(sk), 1,
02bcf28c AB	394	(unsigned long long)avr->dccpavr_ack_seqno,
	395	(unsigned long long)avr->dccpavr_ack_ackno);
	396	dccp_ackvec_throw_record(av, avr);
	397	break;
d23ca15a AB	398	} else if (avr->dccpavr_ack_seqno > ackno)
d23ca15a AB	399	break; /* old news */
ae31c339 ACM	400	}
	401	}
	402
	403	static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
bdf13d20	404	struct sock sk, u64 ackno,
ae31c339 ACM	405	const unsigned char len,
	406	const unsigned char *vector)
	407	{
	408	unsigned char i;
02bcf28c	409	struct dccp_ackvec_record *avr;
ae31c339 ACM	410
ae31c339 ACM	411	/* Check if we actually sent an ACK vector */
02bcf28c	412	if (list_empty(&av->dccpav_records))
ae31c339	413	return;
ae31c339 ACM	414
ae31c339 ACM	415	i = len;
02bcf28c AB	416	/*
	417	* XXX
	418	* I think it might be more efficient to work backwards. See comment on
	419	* rcv_ackno. -sorbo.
	420	*/
	421	avr = list_entry(av->dccpav_records.next, struct dccp_ackvec_record,
	422	dccpavr_node);
ae31c339 ACM	423	while (i--) {
	424	const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
	425	u64 ackno_end_rl;
	426
bdf13d20	427	dccp_set_seqno(&ackno_end_rl, *ackno - rl);
ae31c339 ACM	428
ae31c339 ACM	429	/*
02bcf28c AB	430	* If our AVR sequence number is greater than the ack, go
02bcf28c AB	431	* forward in the AVR list until it is not so.
ae31c339	432	*/
02bcf28c AB	433	list_for_each_entry_from(avr, &av->dccpav_records,
02bcf28c AB	434	dccpavr_node) {
bdf13d20	435	if (!after48(avr->dccpavr_ack_seqno, *ackno))
02bcf28c AB	436	goto found;
	437	}
	438	/* End of the dccpav_records list, not found, exit */
	439	break;
	440	found:
bdf13d20	441	if (between48(avr->dccpavr_ack_seqno, ackno_end_rl, *ackno)) {
8e27e465	442	const u8 state = *vector & DCCP_ACKVEC_STATE_MASK;
ae31c339	443	if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED) {
09dbc389	444	dccp_pr_debug("%s ACK vector 0, len=%d, "
ae31c339 ACM	445	"ack_seqno=%llu, ack_ackno=%llu, "
ae31c339 ACM	446	"ACKED!\n",
09dbc389	447	dccp_role(sk), len,
ae31c339	448	(unsigned long long)
02bcf28c	449	avr->dccpavr_ack_seqno,
ae31c339	450	(unsigned long long)
02bcf28c AB	451	avr->dccpavr_ack_ackno);
02bcf28c AB	452	dccp_ackvec_throw_record(av, avr);
afec35e3	453	break;
ae31c339 ACM	454	}
ae31c339 ACM	455	/*
02bcf28c AB	456	* If it wasn't received, continue scanning... we might
02bcf28c AB	457	* find another one.
ae31c339	458	*/
ae31c339	459	}
ae31c339	460
bdf13d20	461	dccp_set_seqno(ackno, ackno_end_rl - 1);
ae31c339 ACM	462	++vector;
	463	}
	464	}
	465
	466	int dccp_ackvec_parse(struct sock sk, const struct sk_buff skb,
bdf13d20	467	u64 ackno, const u8 opt, const u8 value, const u8 len)
ae31c339	468	{
bdf13d20	469	if (len > DCCP_MAX_ACKVEC_OPT_LEN)
ae31c339 ACM	470	return -1;
	471
	472	/* dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq, value, len); */
	473	dccp_ackvec_check_rcv_ackvector(dccp_sk(sk)->dccps_hc_rx_ackvec, sk,
bdf13d20	474	ackno, len, value);
ae31c339 ACM	475	return 0;
ae31c339 ACM	476	}
9b07ef5d	477
9b07ef5d ACM	478	int __init dccp_ackvec_init(void)
	479	{
	480	dccp_ackvec_slab = kmem_cache_create("dccp_ackvec",
	481	sizeof(struct dccp_ackvec), 0,
20c2df83	482	SLAB_HWCACHE_ALIGN, NULL);
02bcf28c AB	483	if (dccp_ackvec_slab == NULL)
	484	goto out_err;
	485
	486	dccp_ackvec_record_slab =
	487	kmem_cache_create("dccp_ackvec_record",
	488	sizeof(struct dccp_ackvec_record),
20c2df83	489	0, SLAB_HWCACHE_ALIGN, NULL);
02bcf28c AB	490	if (dccp_ackvec_record_slab == NULL)
02bcf28c AB	491	goto out_destroy_slab;
9b07ef5d ACM	492
9b07ef5d ACM	493	return 0;
02bcf28c AB	494
	495	out_destroy_slab:
	496	kmem_cache_destroy(dccp_ackvec_slab);
	497	dccp_ackvec_slab = NULL;
	498	out_err:
59348b19	499	DCCP_CRIT("Unable to create Ack Vector slab cache");
02bcf28c	500	return -ENOBUFS;
9b07ef5d ACM	501	}
	502
	503	void dccp_ackvec_exit(void)
	504	{
	505	if (dccp_ackvec_slab != NULL) {
	506	kmem_cache_destroy(dccp_ackvec_slab);
	507	dccp_ackvec_slab = NULL;
	508	}
02bcf28c AB	509	if (dccp_ackvec_record_slab != NULL) {
	510	kmem_cache_destroy(dccp_ackvec_record_slab);
	511	dccp_ackvec_record_slab = NULL;
	512	}
9b07ef5d	513	}