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-rw-r--r--net/dccp/ackvec.c619
1 files changed, 345 insertions, 274 deletions
diff --git a/net/dccp/ackvec.c b/net/dccp/ackvec.c
index 41819848bdd..1e8be246ad1 100644
--- a/net/dccp/ackvec.c
+++ b/net/dccp/ackvec.c
@@ -1,375 +1,445 @@
/*
* net/dccp/ackvec.c
*
- * An implementation of Ack Vectors for the DCCP protocol
- * Copyright (c) 2007 University of Aberdeen, Scotland, UK
+ * 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;
-struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
+static struct dccp_ackvec_record *dccp_ackvec_record_new(void)
{
- struct dccp_ackvec *av = kmem_cache_zalloc(dccp_ackvec_slab, priority);
+ struct dccp_ackvec_record *avr =
+ kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC);
- if (av != NULL) {
- av->av_buf_head = av->av_buf_tail = DCCPAV_MAX_ACKVEC_LEN - 1;
- INIT_LIST_HEAD(&av->av_records);
- }
- return av;
+ if (avr != NULL)
+ INIT_LIST_HEAD(&avr->avr_node);
+
+ return avr;
}
-static void dccp_ackvec_purge_records(struct dccp_ackvec *av)
+static void dccp_ackvec_record_delete(struct dccp_ackvec_record *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);
+ 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);
}
-void dccp_ackvec_free(struct dccp_ackvec *av)
+static void dccp_ackvec_insert_avr(struct dccp_ackvec *av,
+ struct dccp_ackvec_record *avr)
{
- if (likely(av != NULL)) {
- dccp_ackvec_purge_records(av);
- kmem_cache_free(dccp_ackvec_slab, 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));
}
+
+ list_add(&avr->avr_node, &av->av_records);
}
-/**
- * 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)
+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->av_vec_len, DCCP_MAX_ACKVEC_OPT_LEN);
+ 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;
- avr = kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC);
+ if (elapsed_time != 0 &&
+ dccp_insert_option_elapsed_time(sk, skb, elapsed_time))
+ return -1;
+
+ avr = dccp_ackvec_record_new();
if (avr == NULL)
- return -ENOBUFS;
+ 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_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->av_buf;
+ }
+
+ memcpy(to, from, copylen);
+ from += copylen;
+ to += copylen;
+ len -= copylen;
+ }
- 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);
- /*
- * 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.
- */
- 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.
+ * 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.
*/
- list_add(&avr->avr_node, &av->av_records);
+ 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_pr_debug("Added Vector, ack_seqno=%llu, ack_ackno=%llu (rl=%u)\n",
+ 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->avr_sent_len,
(unsigned long long)avr->avr_ack_seqno,
- (unsigned long long)avr->avr_ack_ackno,
- avr->avr_ack_runlen);
+ (unsigned long long)avr->avr_ack_ackno);
return 0;
}
-static struct dccp_ackvec_record *dccp_ackvec_lookup(struct list_head *av_list,
- const u64 ackno)
+struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
{
- 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;
+ 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);
}
- return NULL;
+
+ return 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)
+void dccp_ackvec_free(struct dccp_ackvec *av)
{
- return (a + b) % DCCPAV_MAX_ACKVEC_LEN;
+ 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);
}
-static inline u16 __ackvec_idx_sub(const u16 a, const u16 b)
+static inline u8 dccp_ackvec_state(const struct dccp_ackvec *av,
+ const u32 index)
{
- return __ackvec_idx_add(a, DCCPAV_MAX_ACKVEC_LEN - b);
+ return av->av_buf[index] & DCCP_ACKVEC_STATE_MASK;
}
-u16 dccp_ackvec_buflen(const struct dccp_ackvec *av)
+static inline u8 dccp_ackvec_len(const struct dccp_ackvec *av,
+ const u32 index)
{
- if (unlikely(av->av_overflow))
- return DCCPAV_MAX_ACKVEC_LEN;
- return __ackvec_idx_sub(av->av_buf_tail, av->av_buf_head);
+ return av->av_buf[index] & DCCP_ACKVEC_LEN_MASK;
}
-/**
- * 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
+/*
+ * 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 void dccp_ackvec_update_old(struct dccp_ackvec *av, s64 distance,
- u64 seqno, enum dccp_ackvec_states state)
+static inline int dccp_ackvec_set_buf_head_state(struct dccp_ackvec *av,
+ const unsigned int packets,
+ const unsigned char state)
{
- u16 ptr = av->av_buf_head;
+ unsigned int gap;
+ long new_head;
- BUG_ON(distance > 0);
- if (unlikely(dccp_ackvec_is_empty(av)))
- return;
+ if (av->av_vec_len + packets > DCCP_MAX_ACKVEC_LEN)
+ return -ENOBUFS;
- do {
- u8 runlen = dccp_ackvec_runlen(av->av_buf + ptr);
+ gap = packets - 1;
+ new_head = av->av_buf_head - packets;
- 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;
+ if (new_head < 0) {
+ if (gap > 0) {
+ memset(av->av_buf, DCCP_ACKVEC_STATE_NOT_RECEIVED,
+ gap + new_head + 1);
+ gap = -new_head;
}
+ new_head += DCCP_MAX_ACKVEC_LEN;
+ }
- distance += runlen + 1;
- ptr = __ackvec_idx_add(ptr, 1);
+ av->av_buf_head = new_head;
- } while (ptr != av->av_buf_tail);
-}
+ if (gap > 0)
+ memset(av->av_buf + av->av_buf_head + 1,
+ DCCP_ACKVEC_STATE_NOT_RECEIVED, gap);
-/* 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);
+ av->av_buf[av->av_buf_head] = state;
+ av->av_vec_len += packets;
+ return 0;
}
-/**
- * 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
+/*
+ * Implements the RFC 4340, Appendix A
*/
-static void dccp_ackvec_add_new(struct dccp_ackvec *av, u32 num_packets,
- u64 seqno, enum dccp_ackvec_states state)
+int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
+ const u64 ackno, const u8 state)
{
- u32 num_cells = num_packets;
+ /*
+ * 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.
+ */
- if (num_packets > DCCPAV_BURST_THRESH) {
- u32 lost_packets = num_packets - 1;
+ /* 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);
- DCCP_WARN("Warning: large burst loss (%u)\n", lost_packets);
/*
- * 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.
+ * Look if the state of this packet is the same as the
+ * previous ackno and if so if we can bump the head len.
*/
- for (num_packets = num_cells = 1; lost_packets; ++num_cells) {
- u8 len = min(lost_packets, (u32)DCCPAV_MAX_RUNLEN);
-
- av->av_buf_head = __ackvec_idx_sub(av->av_buf_head, 1);
- av->av_buf[av->av_buf_head] = DCCPAV_NOT_RECEIVED | len;
+ 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;
- lost_packets -= len;
+ 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;
}
}
- 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;
-
- av->av_buf[av->av_buf_head] = state;
- av->av_buf_ackno = seqno;
+ av->av_buf_ackno = ackno;
+ av->av_time = ktime_get_real();
+out:
+ return 0;
- if (num_packets > 1)
- dccp_ackvec_reserve_seats(av, num_packets - 1);
+out_duplicate:
+ /* Duplicate packet */
+ dccp_pr_debug("Received a dup or already considered lost "
+ "packet: %llu\n", (unsigned long long)ackno);
+ return -EILSEQ;
}
-/**
- * dccp_ackvec_input - Register incoming packet in the buffer
- */
-void dccp_ackvec_input(struct dccp_ackvec *av, struct sk_buff *skb)
+static void dccp_ackvec_throw_record(struct dccp_ackvec *av,
+ struct dccp_ackvec_record *avr)
{
- u64 seqno = DCCP_SKB_CB(skb)->dccpd_seq;
- enum dccp_ackvec_states state = DCCPAV_RECEIVED;
+ struct dccp_ackvec_record *next;
- if (dccp_ackvec_is_empty(av)) {
- dccp_ackvec_add_new(av, 1, seqno, state);
- av->av_tail_ackno = seqno;
+ /* 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;
- } else {
- s64 num_packets = dccp_delta_seqno(av->av_buf_ackno, seqno);
- u8 *current_head = av->av_buf + av->av_buf_head;
-
- if (num_packets == 1 &&
- dccp_ackvec_state(current_head) == state &&
- dccp_ackvec_runlen(current_head) < DCCPAV_MAX_RUNLEN) {
+ /* 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);
+ }
+}
- *current_head += 1;
- av->av_buf_ackno = seqno;
+void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, struct sock *sk,
+ const u64 ackno)
+{
+ struct dccp_ackvec_record *avr;
- } else if (num_packets > 0) {
- dccp_ackvec_add_new(av, num_packets, seqno, state);
- } else {
- dccp_ackvec_update_old(av, num_packets, seqno, state);
- }
+ /*
+ * 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 */
}
}
-/**
- * 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)
- {
- struct dccp_ackvec_record *avr, *next;
- u8 runlen_now, eff_runlen;
- s64 delta;
+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;
- avr = dccp_ackvec_lookup(&av->av_records, ackno);
- if (avr == NULL)
+ /* Check if we actually sent an ACK vector */
+ if (list_empty(&av->av_records))
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;
- runlen_now = dccp_ackvec_runlen(av->av_buf + avr->avr_ack_ptr);
+ i = len;
/*
- * 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.
+ * XXX
+ * I think it might be more efficient to work backwards. See comment on
+ * rcv_ackno. -sorbo.
*/
- if (runlen_now > eff_runlen) {
+ 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;
- av->av_buf[avr->avr_ack_ptr] -= eff_runlen + 1;
- av->av_buf_tail = __ackvec_idx_add(avr->avr_ack_ptr, 1);
+ dccp_set_seqno(&ackno_end_rl, *ackno - rl);
- /* 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;
/*
- * 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.
+ * If our AVR sequence number is greater than the ack, go
+ * forward in the AVR list until it is not so.
*/
- av->av_overflow = 0;
- }
-
- /*
- * 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);
+ 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.
+ */
+ }
-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);
+ dccp_set_seqno(ackno, ackno_end_rl - 1);
+ ++vector;
}
}
-/*
- * 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)
+int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
+ u64 *ackno, const u8 opt, const u8 *value, const u8 len)
{
- struct dccp_ackvec_parsed *new = kmalloc(sizeof(*new), GFP_ATOMIC);
-
- if (new == NULL)
- return -ENOBUFS;
- new->vec = vec;
- new->len = len;
- new->nonce = nonce;
+ if (len > DCCP_MAX_ACKVEC_OPT_LEN)
+ return -1;
- list_add_tail(&new->node, head);
+ /* 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;
}
-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)
{
@@ -379,9 +449,10 @@ 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;