dccp ccid-2: Remove old infrastructure
This removes * functions for which updates have been provided in the preceding patches and * the @av_vec_len field - it is no longer necessary since the buffer length is now always computed dynamically. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This commit is contained in:
Gerrit Renker
parent
d83447f094
commit
52394eecec
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@ -9,18 +9,10 @@
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; version 2 of the License;
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*/
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#include "ackvec.h"
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#include "dccp.h"
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#include <linux/init.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/skbuff.h>
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#include <linux/slab.h>
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#include <net/sock.h>
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static struct kmem_cache *dccp_ackvec_slab;
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static struct kmem_cache *dccp_ackvec_record_slab;
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@ -281,249 +273,6 @@ void dccp_ackvec_input(struct dccp_ackvec *av, struct sk_buff *skb)
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}
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}
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/*
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* If several packets are missing, the HC-Receiver may prefer to enter multiple
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* bytes with run length 0, rather than a single byte with a larger run length;
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* this simplifies table updates if one of the missing packets arrives.
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*/
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static inline int dccp_ackvec_set_buf_head_state(struct dccp_ackvec *av,
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const unsigned int packets,
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const unsigned char state)
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{
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long gap;
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long new_head;
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if (av->av_vec_len + packets > DCCPAV_MAX_ACKVEC_LEN)
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return -ENOBUFS;
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gap = packets - 1;
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new_head = av->av_buf_head - packets;
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if (new_head < 0) {
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if (gap > 0) {
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memset(av->av_buf, DCCPAV_NOT_RECEIVED,
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gap + new_head + 1);
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gap = -new_head;
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}
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new_head += DCCPAV_MAX_ACKVEC_LEN;
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}
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av->av_buf_head = new_head;
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if (gap > 0)
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memset(av->av_buf + av->av_buf_head + 1,
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DCCPAV_NOT_RECEIVED, gap);
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av->av_buf[av->av_buf_head] = state;
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av->av_vec_len += packets;
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return 0;
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}
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/*
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* Implements the RFC 4340, Appendix A
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*/
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int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
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const u64 ackno, const u8 state)
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{
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u8 *cur_head = av->av_buf + av->av_buf_head,
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*buf_end = av->av_buf + DCCPAV_MAX_ACKVEC_LEN;
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/*
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* Check at the right places if the buffer is full, if it is, tell the
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* caller to start dropping packets till the HC-Sender acks our ACK
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* vectors, when we will free up space in av_buf.
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*
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* We may well decide to do buffer compression, etc, but for now lets
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* just drop.
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*
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* From Appendix A.1.1 (`New Packets'):
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*
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* Of course, the circular buffer may overflow, either when the
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* HC-Sender is sending data at a very high rate, when the
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* HC-Receiver's acknowledgements are not reaching the HC-Sender,
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* or when the HC-Sender is forgetting to acknowledge those acks
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* (so the HC-Receiver is unable to clean up old state). In this
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* case, the HC-Receiver should either compress the buffer (by
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* increasing run lengths when possible), transfer its state to
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* a larger buffer, or, as a last resort, drop all received
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* packets, without processing them whatsoever, until its buffer
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* shrinks again.
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*/
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/* See if this is the first ackno being inserted */
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if (av->av_vec_len == 0) {
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*cur_head = state;
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av->av_vec_len = 1;
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} else if (after48(ackno, av->av_buf_ackno)) {
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const u64 delta = dccp_delta_seqno(av->av_buf_ackno, ackno);
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/*
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* Look if the state of this packet is the same as the
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* previous ackno and if so if we can bump the head len.
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*/
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if (delta == 1 && dccp_ackvec_state(cur_head) == state &&
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dccp_ackvec_runlen(cur_head) < DCCPAV_MAX_RUNLEN)
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*cur_head += 1;
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else if (dccp_ackvec_set_buf_head_state(av, delta, state))
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return -ENOBUFS;
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} else {
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/*
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* A.1.2. Old Packets
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*
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* When a packet with Sequence Number S <= buf_ackno
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* arrives, the HC-Receiver will scan the table for
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* the byte corresponding to S. (Indexing structures
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* could reduce the complexity of this scan.)
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*/
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u64 delta = dccp_delta_seqno(ackno, av->av_buf_ackno);
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while (1) {
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const u8 len = dccp_ackvec_runlen(cur_head);
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/*
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* valid packets not yet in av_buf have a reserved
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* entry, with a len equal to 0.
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*/
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if (*cur_head == DCCPAV_NOT_RECEIVED && delta == 0) {
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dccp_pr_debug("Found %llu reserved seat!\n",
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(unsigned long long)ackno);
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*cur_head = state;
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goto out;
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}
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/* len == 0 means one packet */
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if (delta < len + 1)
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goto out_duplicate;
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delta -= len + 1;
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if (++cur_head == buf_end)
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cur_head = av->av_buf;
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}
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}
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av->av_buf_ackno = ackno;
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out:
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return 0;
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out_duplicate:
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/* Duplicate packet */
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dccp_pr_debug("Received a dup or already considered lost "
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"packet: %llu\n", (unsigned long long)ackno);
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return -EILSEQ;
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}
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static void dccp_ackvec_throw_record(struct dccp_ackvec *av,
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struct dccp_ackvec_record *avr)
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{
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struct dccp_ackvec_record *next;
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/* sort out vector length */
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if (av->av_buf_head <= avr->avr_ack_ptr)
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av->av_vec_len = avr->avr_ack_ptr - av->av_buf_head;
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else
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av->av_vec_len = DCCPAV_MAX_ACKVEC_LEN - 1 -
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av->av_buf_head + avr->avr_ack_ptr;
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/* free records */
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list_for_each_entry_safe_from(avr, next, &av->av_records, avr_node) {
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list_del(&avr->avr_node);
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kmem_cache_free(dccp_ackvec_record_slab, avr);
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}
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}
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void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, struct sock *sk,
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const u64 ackno)
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{
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struct dccp_ackvec_record *avr;
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/*
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* If we traverse backwards, it should be faster when we have large
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* windows. We will be receiving ACKs for stuff we sent a while back
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* -sorbo.
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*/
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list_for_each_entry_reverse(avr, &av->av_records, avr_node) {
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if (ackno == avr->avr_ack_seqno) {
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dccp_pr_debug("%s ACK packet 0, len=%d, ack_seqno=%llu, "
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"ack_ackno=%llu, ACKED!\n",
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dccp_role(sk), avr->avr_ack_runlen,
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(unsigned long long)avr->avr_ack_seqno,
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(unsigned long long)avr->avr_ack_ackno);
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dccp_ackvec_throw_record(av, avr);
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break;
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} else if (avr->avr_ack_seqno > ackno)
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break; /* old news */
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}
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}
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static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
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struct sock *sk, u64 *ackno,
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const unsigned char len,
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const unsigned char *vector)
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{
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unsigned char i;
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struct dccp_ackvec_record *avr;
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/* Check if we actually sent an ACK vector */
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if (list_empty(&av->av_records))
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return;
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i = len;
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/*
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* XXX
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* I think it might be more efficient to work backwards. See comment on
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* rcv_ackno. -sorbo.
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*/
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avr = list_entry(av->av_records.next, struct dccp_ackvec_record, avr_node);
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while (i--) {
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const u8 rl = dccp_ackvec_runlen(vector);
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u64 ackno_end_rl;
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dccp_set_seqno(&ackno_end_rl, *ackno - rl);
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/*
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* If our AVR sequence number is greater than the ack, go
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* forward in the AVR list until it is not so.
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*/
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list_for_each_entry_from(avr, &av->av_records, avr_node) {
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if (!after48(avr->avr_ack_seqno, *ackno))
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goto found;
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}
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/* End of the av_records list, not found, exit */
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break;
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found:
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if (between48(avr->avr_ack_seqno, ackno_end_rl, *ackno)) {
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if (dccp_ackvec_state(vector) != DCCPAV_NOT_RECEIVED) {
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dccp_pr_debug("%s ACK vector 0, len=%d, "
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"ack_seqno=%llu, ack_ackno=%llu, "
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"ACKED!\n",
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dccp_role(sk), len,
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(unsigned long long)
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avr->avr_ack_seqno,
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(unsigned long long)
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avr->avr_ack_ackno);
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dccp_ackvec_throw_record(av, avr);
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break;
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}
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/*
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* If it wasn't received, continue scanning... we might
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* find another one.
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*/
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}
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dccp_set_seqno(ackno, ackno_end_rl - 1);
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++vector;
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}
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}
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int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
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u64 *ackno, const u8 opt, const u8 *value, const u8 len)
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{
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if (len > DCCP_SINGLE_OPT_MAXLEN)
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return -1;
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/* dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq, value, len); */
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dccp_ackvec_check_rcv_ackvector(dccp_sk(sk)->dccps_hc_rx_ackvec, sk,
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ackno, len, value);
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return 0;
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}
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/**
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* dccp_ackvec_clear_state - Perform house-keeping / garbage-collection
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* This routine is called when the peer acknowledges the receipt of Ack Vectors
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@ -64,7 +64,6 @@ static inline u8 dccp_ackvec_state(const u8 *cell)
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* %DCCP_SINGLE_OPT_MAXLEN cells in the live portion of @av_buf
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* @av_overflow: if 1 then buf_head == buf_tail indicates buffer wraparound
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* @av_records: list of %dccp_ackvec_record (Ack Vectors sent previously)
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* @av_veclen: length of the live portion of @av_buf
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*/
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struct dccp_ackvec {
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u8 av_buf[DCCPAV_MAX_ACKVEC_LEN];
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@ -75,7 +74,6 @@ struct dccp_ackvec {
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bool av_buf_nonce[DCCPAV_NUM_ACKVECS];
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u8 av_overflow:1;
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struct list_head av_records;
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u16 av_vec_len;
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};
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/** struct dccp_ackvec_record - Records information about sent Ack Vectors
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@ -101,24 +99,12 @@ struct dccp_ackvec_record {
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u8 avr_ack_nonce:1;
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};
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struct sock;
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struct sk_buff;
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extern int dccp_ackvec_init(void);
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extern void dccp_ackvec_exit(void);
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extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority);
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extern void dccp_ackvec_free(struct dccp_ackvec *av);
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extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
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const u64 ackno, const u8 state);
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extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
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struct sock *sk, const u64 ackno);
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extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
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u64 *ackno, const u8 opt,
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const u8 *value, const u8 len);
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extern void dccp_ackvec_input(struct dccp_ackvec *av, struct sk_buff *skb);
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extern int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8 sum);
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extern void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno);
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