/*
* net/dccp/ackvec.c
*
- * An implementation of the DCCP protocol
+ * An implementation of Ack Vectors for the DCCP protocol
+ * Copyright (c) 2007 University of Aberdeen, Scotland, UK
* 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/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 *dccp_ackvec_alloc(const gfp_t priority)
{
- struct dccp_ackvec_record *avr =
- kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC);
+ struct dccp_ackvec *av = kmem_cache_zalloc(dccp_ackvec_slab, priority);
- if (avr != NULL)
- INIT_LIST_HEAD(&avr->avr_node);
-
- return avr;
+ if (av != NULL) {
+ av->av_buf_head = av->av_buf_tail = DCCPAV_MAX_ACKVEC_LEN - 1;
+ INIT_LIST_HEAD(&av->av_records);
+ }
+ return av;
}
-static void dccp_ackvec_record_delete(struct dccp_ackvec_record *avr)
+static void dccp_ackvec_purge_records(struct dccp_ackvec *av)
{
- if (unlikely(avr == NULL))
- return;
- /* Check if deleting a linked record */
- WARN_ON(!list_empty(&avr->avr_node));
- kmem_cache_free(dccp_ackvec_record_slab, avr);
+ struct dccp_ackvec_record *cur, *next;
+
+ list_for_each_entry_safe(cur, next, &av->av_records, avr_node)
+ kmem_cache_free(dccp_ackvec_record_slab, cur);
+ INIT_LIST_HEAD(&av->av_records);
}
-static void dccp_ackvec_insert_avr(struct dccp_ackvec *av,
- struct dccp_ackvec_record *avr)
+void dccp_ackvec_free(struct dccp_ackvec *av)
{
- /*
- * 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->av_records)) {
- const struct dccp_ackvec_record *head =
- list_entry(av->av_records.next,
- struct dccp_ackvec_record,
- avr_node);
- BUG_ON(before48(avr->avr_ack_seqno, head->avr_ack_seqno));
+ if (likely(av != NULL)) {
+ dccp_ackvec_purge_records(av);
+ kmem_cache_free(dccp_ackvec_slab, av);
}
-
- list_add(&avr->avr_node, &av->av_records);
}
-int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
+/**
+ * dccp_ackvec_update_records - Record information about sent Ack Vectors
+ * @av: Ack Vector records to update
+ * @seqno: Sequence number of the packet carrying the Ack Vector just sent
+ * @nonce_sum: The sum of all buffer nonces contained in the Ack Vector
+ */
+int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seqno, u8 nonce_sum)
{
- 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 u8 nr_opts = DIV_ROUND_UP(av->av_vec_len, DCCP_SINGLE_OPT_MAXLEN);
- u16 len = av->av_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->av_time);
- elapsed_time = delta / 10;
- if (elapsed_time != 0 &&
- dccp_insert_option_elapsed_time(skb, elapsed_time))
- return -1;
-
- avr = dccp_ackvec_record_new();
+ avr = kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC);
if (avr == NULL)
- return -1;
-
- DCCP_SKB_CB(skb)->dccpd_opt_len += len;
-
- to = skb_push(skb, len);
- len = av->av_vec_len;
- from = av->av_buf + av->av_buf_head;
- tail = av->av_buf + DCCP_MAX_ACKVEC_LEN;
-
- for (i = 0; i < nr_opts; ++i) {
- int copylen = len;
-
- if (len > DCCP_SINGLE_OPT_MAXLEN)
- copylen = DCCP_SINGLE_OPT_MAXLEN;
-
- *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->av_buf;
- }
-
- memcpy(to, from, copylen);
- from += copylen;
- to += copylen;
- len -= copylen;
- }
+ return -ENOBUFS;
+ avr->avr_ack_seqno = seqno;
+ avr->avr_ack_ptr = av->av_buf_head;
+ avr->avr_ack_ackno = av->av_buf_ackno;
+ avr->avr_ack_nonce = nonce_sum;
+ avr->avr_ack_runlen = dccp_ackvec_runlen(av->av_buf + av->av_buf_head);
/*
- * 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.
+ * When the buffer overflows, we keep no more than one record. This is
+ * the simplest way of disambiguating sender-Acks dating from before the
+ * overflow from sender-Acks which refer to after the overflow; a simple
+ * solution is preferable here since we are handling an exception.
*/
- avr->avr_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
- avr->avr_ack_ptr = av->av_buf_head;
- avr->avr_ack_ackno = av->av_buf_ackno;
- avr->avr_ack_nonce = av->av_buf_nonce;
- avr->avr_sent_len = av->av_vec_len;
-
- dccp_ackvec_insert_avr(av, avr);
+ if (av->av_overflow)
+ dccp_ackvec_purge_records(av);
+ /*
+ * Since GSS is incremented for each packet, the list is automatically
+ * arranged in descending order of @ack_seqno.
+ */
+ list_add(&avr->avr_node, &av->av_records);
- dccp_pr_debug("%s ACK Vector 0, len=%d, ack_seqno=%llu, "
- "ack_ackno=%llu\n",
- dccp_role(sk), avr->avr_sent_len,
+ dccp_pr_debug("Added Vector, ack_seqno=%llu, ack_ackno=%llu (rl=%u)\n",
(unsigned long long)avr->avr_ack_seqno,
- (unsigned long long)avr->avr_ack_ackno);
+ (unsigned long long)avr->avr_ack_ackno,
+ avr->avr_ack_runlen);
return 0;
}
-struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
+static struct dccp_ackvec_record *dccp_ackvec_lookup(struct list_head *av_list,
+ const u64 ackno)
{
- struct dccp_ackvec *av = kmem_cache_alloc(dccp_ackvec_slab, priority);
-
- if (av != NULL) {
- av->av_buf_head = DCCP_MAX_ACKVEC_LEN - 1;
- av->av_buf_ackno = UINT48_MAX + 1;
- av->av_buf_nonce = 0;
- av->av_time = ktime_set(0, 0);
- av->av_vec_len = 0;
- INIT_LIST_HEAD(&av->av_records);
+ struct dccp_ackvec_record *avr;
+ /*
+ * Exploit that records are inserted in descending order of sequence
+ * number, start with the oldest record first. If @ackno is `before'
+ * the earliest ack_ackno, the packet is too old to be considered.
+ */
+ list_for_each_entry_reverse(avr, av_list, avr_node) {
+ if (avr->avr_ack_seqno == ackno)
+ return avr;
+ if (before48(ackno, avr->avr_ack_seqno))
+ break;
}
-
- return av;
+ return NULL;
}
-void dccp_ackvec_free(struct dccp_ackvec *av)
+/*
+ * Buffer index and length computation using modulo-buffersize arithmetic.
+ * Note that, as pointers move from right to left, head is `before' tail.
+ */
+static inline u16 __ackvec_idx_add(const u16 a, const u16 b)
{
- if (unlikely(av == NULL))
- return;
-
- if (!list_empty(&av->av_records)) {
- struct dccp_ackvec_record *avr, *next;
-
- list_for_each_entry_safe(avr, next, &av->av_records, avr_node) {
- list_del_init(&avr->avr_node);
- dccp_ackvec_record_delete(avr);
- }
- }
-
- kmem_cache_free(dccp_ackvec_slab, av);
+ return (a + b) % DCCPAV_MAX_ACKVEC_LEN;
}
-static inline u8 dccp_ackvec_state(const struct dccp_ackvec *av,
- const u32 index)
+static inline u16 __ackvec_idx_sub(const u16 a, const u16 b)
{
- return av->av_buf[index] & DCCP_ACKVEC_STATE_MASK;
+ return __ackvec_idx_add(a, DCCPAV_MAX_ACKVEC_LEN - b);
}
-static inline u8 dccp_ackvec_len(const struct dccp_ackvec *av,
- const u32 index)
+u16 dccp_ackvec_buflen(const struct dccp_ackvec *av)
{
- return av->av_buf[index] & DCCP_ACKVEC_LEN_MASK;
+ if (unlikely(av->av_overflow))
+ return DCCPAV_MAX_ACKVEC_LEN;
+ return __ackvec_idx_sub(av->av_buf_tail, av->av_buf_head);
}
-/*
- * 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.
+/**
+ * dccp_ackvec_update_old - Update previous state as per RFC 4340, 11.4.1
+ * @av: non-empty buffer to update
+ * @distance: negative or zero distance of @seqno from buf_ackno downward
+ * @seqno: the (old) sequence number whose record is to be updated
+ * @state: state in which packet carrying @seqno was received
*/
-static inline int dccp_ackvec_set_buf_head_state(struct dccp_ackvec *av,
- const unsigned int packets,
- const unsigned char state)
+static void dccp_ackvec_update_old(struct dccp_ackvec *av, s64 distance,
+ u64 seqno, enum dccp_ackvec_states state)
{
- long gap;
- long new_head;
+ u16 ptr = av->av_buf_head;
- if (av->av_vec_len + packets > DCCP_MAX_ACKVEC_LEN)
- return -ENOBUFS;
+ BUG_ON(distance > 0);
+ if (unlikely(dccp_ackvec_is_empty(av)))
+ return;
- gap = packets - 1;
- new_head = av->av_buf_head - packets;
+ do {
+ u8 runlen = dccp_ackvec_runlen(av->av_buf + ptr);
- if (new_head < 0) {
- if (gap > 0) {
- memset(av->av_buf, DCCP_ACKVEC_STATE_NOT_RECEIVED,
- gap + new_head + 1);
- gap = -new_head;
+ if (distance + runlen >= 0) {
+ /*
+ * Only update the state if packet has not been received
+ * yet. This is OK as per the second table in RFC 4340,
+ * 11.4.1; i.e. here we are using the following table:
+ * RECEIVED
+ * 0 1 3
+ * S +---+---+---+
+ * T 0 | 0 | 0 | 0 |
+ * O +---+---+---+
+ * R 1 | 1 | 1 | 1 |
+ * E +---+---+---+
+ * D 3 | 0 | 1 | 3 |
+ * +---+---+---+
+ * The "Not Received" state was set by reserve_seats().
+ */
+ if (av->av_buf[ptr] == DCCPAV_NOT_RECEIVED)
+ av->av_buf[ptr] = state;
+ else
+ dccp_pr_debug("Not changing %llu state to %u\n",
+ (unsigned long long)seqno, state);
+ break;
}
- new_head += DCCP_MAX_ACKVEC_LEN;
- }
- av->av_buf_head = new_head;
+ distance += runlen + 1;
+ ptr = __ackvec_idx_add(ptr, 1);
- if (gap > 0)
- memset(av->av_buf + av->av_buf_head + 1,
- DCCP_ACKVEC_STATE_NOT_RECEIVED, gap);
+ } while (ptr != av->av_buf_tail);
+}
- av->av_buf[av->av_buf_head] = state;
- av->av_vec_len += packets;
- return 0;
+/* Mark @num entries after buf_head as "Not yet received". */
+static void dccp_ackvec_reserve_seats(struct dccp_ackvec *av, u16 num)
+{
+ u16 start = __ackvec_idx_add(av->av_buf_head, 1),
+ len = DCCPAV_MAX_ACKVEC_LEN - start;
+
+ /* check for buffer wrap-around */
+ if (num > len) {
+ memset(av->av_buf + start, DCCPAV_NOT_RECEIVED, len);
+ start = 0;
+ num -= len;
+ }
+ if (num)
+ memset(av->av_buf + start, DCCPAV_NOT_RECEIVED, num);
}
-/*
- * Implements the RFC 4340, Appendix A
+/**
+ * dccp_ackvec_add_new - Record one or more new entries in Ack Vector buffer
+ * @av: container of buffer to update (can be empty or non-empty)
+ * @num_packets: number of packets to register (must be >= 1)
+ * @seqno: sequence number of the first packet in @num_packets
+ * @state: state in which packet carrying @seqno was received
*/
-int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
- const u64 ackno, const u8 state)
+static void dccp_ackvec_add_new(struct dccp_ackvec *av, u32 num_packets,
+ u64 seqno, enum dccp_ackvec_states 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 av_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.
- */
+ u32 num_cells = num_packets;
- /* See if this is the first ackno being inserted */
- if (av->av_vec_len == 0) {
- av->av_buf[av->av_buf_head] = state;
- av->av_vec_len = 1;
- } else if (after48(ackno, av->av_buf_ackno)) {
- const u64 delta = dccp_delta_seqno(av->av_buf_ackno, ackno);
+ if (num_packets > DCCPAV_BURST_THRESH) {
+ u32 lost_packets = num_packets - 1;
+ DCCP_WARN("Warning: large burst loss (%u)\n", lost_packets);
/*
- * Look if the state of this packet is the same as the
- * previous ackno and if so if we can bump the head len.
+ * We received 1 packet and have a loss of size "num_packets-1"
+ * which we squeeze into num_cells-1 rather than reserving an
+ * entire byte for each lost packet.
+ * The reason is that the vector grows in O(burst_length); when
+ * it grows too large there will no room left for the payload.
+ * This is a trade-off: if a few packets out of the burst show
+ * up later, their state will not be changed; it is simply too
+ * costly to reshuffle/reallocate/copy the buffer each time.
+ * Should such problems persist, we will need to switch to a
+ * different underlying data structure.
*/
- if (delta == 1 &&
- dccp_ackvec_state(av, av->av_buf_head) == state &&
- dccp_ackvec_len(av, av->av_buf_head) < DCCP_ACKVEC_LEN_MASK)
- av->av_buf[av->av_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->av_buf_ackno);
- u32 index = av->av_buf_head;
+ for (num_packets = num_cells = 1; lost_packets; ++num_cells) {
+ u8 len = min(lost_packets, (u32)DCCPAV_MAX_RUNLEN);
- while (1) {
- const u8 len = dccp_ackvec_len(av, index);
- const u8 av_state = dccp_ackvec_state(av, index);
- /*
- * valid packets not yet in av_buf have a reserved
- * entry, with a len equal to 0.
- */
- if (av_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->av_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->av_buf_head = __ackvec_idx_sub(av->av_buf_head, 1);
+ av->av_buf[av->av_buf_head] = DCCPAV_NOT_RECEIVED | len;
+
+ lost_packets -= len;
}
}
- av->av_buf_ackno = ackno;
- av->av_time = ktime_get_real();
-out:
- return 0;
+ if (num_cells + dccp_ackvec_buflen(av) >= DCCPAV_MAX_ACKVEC_LEN) {
+ DCCP_CRIT("Ack Vector buffer overflow: dropping old entries\n");
+ av->av_overflow = true;
+ }
+
+ av->av_buf_head = __ackvec_idx_sub(av->av_buf_head, num_packets);
+ if (av->av_overflow)
+ av->av_buf_tail = av->av_buf_head;
-out_duplicate:
- /* Duplicate packet */
- dccp_pr_debug("Received a dup or already considered lost "
- "packet: %llu\n", (unsigned long long)ackno);
- return -EILSEQ;
+ av->av_buf[av->av_buf_head] = state;
+ av->av_buf_ackno = seqno;
+
+ if (num_packets > 1)
+ dccp_ackvec_reserve_seats(av, num_packets - 1);
}
-static void dccp_ackvec_throw_record(struct dccp_ackvec *av,
- struct dccp_ackvec_record *avr)
+/**
+ * dccp_ackvec_input - Register incoming packet in the buffer
+ */
+void dccp_ackvec_input(struct dccp_ackvec *av, struct sk_buff *skb)
{
- struct dccp_ackvec_record *next;
+ u64 seqno = DCCP_SKB_CB(skb)->dccpd_seq;
+ enum dccp_ackvec_states state = DCCPAV_RECEIVED;
- /* sort out vector length */
- if (av->av_buf_head <= avr->avr_ack_ptr)
- av->av_vec_len = avr->avr_ack_ptr - av->av_buf_head;
- else
- av->av_vec_len = DCCP_MAX_ACKVEC_LEN - 1 -
- av->av_buf_head + avr->avr_ack_ptr;
+ if (dccp_ackvec_is_empty(av)) {
+ dccp_ackvec_add_new(av, 1, seqno, state);
+ av->av_tail_ackno = seqno;
- /* free records */
- list_for_each_entry_safe_from(avr, next, &av->av_records, avr_node) {
- list_del_init(&avr->avr_node);
- dccp_ackvec_record_delete(avr);
- }
-}
+ } else {
+ s64 num_packets = dccp_delta_seqno(av->av_buf_ackno, seqno);
+ u8 *current_head = av->av_buf + av->av_buf_head;
-void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, struct sock *sk,
- const u64 ackno)
-{
- struct dccp_ackvec_record *avr;
+ if (num_packets == 1 &&
+ dccp_ackvec_state(current_head) == state &&
+ dccp_ackvec_runlen(current_head) < DCCPAV_MAX_RUNLEN) {
- /*
- * 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->av_records, avr_node) {
- if (ackno == avr->avr_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->avr_ack_seqno,
- (unsigned long long)avr->avr_ack_ackno);
- dccp_ackvec_throw_record(av, avr);
- break;
- } else if (avr->avr_ack_seqno > ackno)
- break; /* old news */
+ *current_head += 1;
+ av->av_buf_ackno = seqno;
+
+ } else if (num_packets > 0) {
+ dccp_ackvec_add_new(av, num_packets, seqno, state);
+ } else {
+ dccp_ackvec_update_old(av, num_packets, seqno, state);
+ }
}
}
-static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
- struct sock *sk, u64 *ackno,
- const unsigned char len,
- const unsigned char *vector)
+/**
+ * dccp_ackvec_clear_state - Perform house-keeping / garbage-collection
+ * This routine is called when the peer acknowledges the receipt of Ack Vectors
+ * up to and including @ackno. While based on on section A.3 of RFC 4340, here
+ * are additional precautions to prevent corrupted buffer state. In particular,
+ * we use tail_ackno to identify outdated records; it always marks the earliest
+ * packet of group (2) in 11.4.2.
+ */
+void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno)
{
- unsigned char i;
- struct dccp_ackvec_record *avr;
+ struct dccp_ackvec_record *avr, *next;
+ u8 runlen_now, eff_runlen;
+ s64 delta;
- /* Check if we actually sent an ACK vector */
- if (list_empty(&av->av_records))
+ avr = dccp_ackvec_lookup(&av->av_records, ackno);
+ if (avr == NULL)
return;
+ /*
+ * Deal with outdated acknowledgments: this arises when e.g. there are
+ * several old records and the acks from the peer come in slowly. In
+ * that case we may still have records that pre-date tail_ackno.
+ */
+ delta = dccp_delta_seqno(av->av_tail_ackno, avr->avr_ack_ackno);
+ if (delta < 0)
+ goto free_records;
+ /*
+ * Deal with overlapping Ack Vectors: don't subtract more than the
+ * number of packets between tail_ackno and ack_ackno.
+ */
+ eff_runlen = delta < avr->avr_ack_runlen ? delta : avr->avr_ack_runlen;
- i = len;
+ runlen_now = dccp_ackvec_runlen(av->av_buf + avr->avr_ack_ptr);
/*
- * XXX
- * I think it might be more efficient to work backwards. See comment on
- * rcv_ackno. -sorbo.
+ * The run length of Ack Vector cells does not decrease over time. If
+ * the run length is the same as at the time the Ack Vector was sent, we
+ * free the ack_ptr cell. That cell can however not be freed if the run
+ * length has increased: in this case we need to move the tail pointer
+ * backwards (towards higher indices), to its next-oldest neighbour.
*/
- avr = list_entry(av->av_records.next, struct dccp_ackvec_record, avr_node);
- while (i--) {
- const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
- u64 ackno_end_rl;
+ if (runlen_now > eff_runlen) {
- dccp_set_seqno(&ackno_end_rl, *ackno - rl);
+ av->av_buf[avr->avr_ack_ptr] -= eff_runlen + 1;
+ av->av_buf_tail = __ackvec_idx_add(avr->avr_ack_ptr, 1);
+ /* This move may not have cleared the overflow flag. */
+ if (av->av_overflow)
+ av->av_overflow = (av->av_buf_head == av->av_buf_tail);
+ } else {
+ av->av_buf_tail = avr->avr_ack_ptr;
/*
- * If our AVR sequence number is greater than the ack, go
- * forward in the AVR list until it is not so.
+ * We have made sure that avr points to a valid cell within the
+ * buffer. This cell is either older than head, or equals head
+ * (empty buffer): in both cases we no longer have any overflow.
*/
- list_for_each_entry_from(avr, &av->av_records, avr_node) {
- if (!after48(avr->avr_ack_seqno, *ackno))
- goto found;
- }
- /* End of the av_records list, not found, exit */
- break;
-found:
- if (between48(avr->avr_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->avr_ack_seqno,
- (unsigned long long)
- avr->avr_ack_ackno);
- dccp_ackvec_throw_record(av, avr);
- break;
- }
- /*
- * If it wasn't received, continue scanning... we might
- * find another one.
- */
- }
+ av->av_overflow = 0;
+ }
- dccp_set_seqno(ackno, ackno_end_rl - 1);
- ++vector;
+ /*
+ * The peer has acknowledged up to and including ack_ackno. Hence the
+ * first packet in group (2) of 11.4.2 is the successor of ack_ackno.
+ */
+ av->av_tail_ackno = ADD48(avr->avr_ack_ackno, 1);
+
+free_records:
+ list_for_each_entry_safe_from(avr, next, &av->av_records, avr_node) {
+ list_del(&avr->avr_node);
+ kmem_cache_free(dccp_ackvec_record_slab, avr);
}
}
-int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
- u64 *ackno, const u8 opt, const u8 *value, const u8 len)
+/*
+ * Routines to keep track of Ack Vectors received in an skb
+ */
+int dccp_ackvec_parsed_add(struct list_head *head, u8 *vec, u8 len, u8 nonce)
{
- if (len > DCCP_SINGLE_OPT_MAXLEN)
- return -1;
+ struct dccp_ackvec_parsed *new = kmalloc(sizeof(*new), GFP_ATOMIC);
+
+ if (new == NULL)
+ return -ENOBUFS;
+ new->vec = vec;
+ new->len = len;
+ new->nonce = nonce;
- /* 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);
+ list_add_tail(&new->node, head);
return 0;
}
+EXPORT_SYMBOL_GPL(dccp_ackvec_parsed_add);
+
+void dccp_ackvec_parsed_cleanup(struct list_head *parsed_chunks)
+{
+ struct dccp_ackvec_parsed *cur, *next;
+
+ list_for_each_entry_safe(cur, next, parsed_chunks, node)
+ kfree(cur);
+ INIT_LIST_HEAD(parsed_chunks);
+}
+EXPORT_SYMBOL_GPL(dccp_ackvec_parsed_cleanup);
int __init dccp_ackvec_init(void)
{
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);
+ 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;
projects / mv-sheeva.git / blobdiff