Coalesce two identical UCB licenses into a single license instance with
one set of copyright years. White space and comment cleanup. Export $FreeBSD$ via __FBSDID.
This commit is contained in:
Robert Watson
parent
b31d5b56ec
commit
632bbf0f5b
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=169469
@ -1,6 +1,7 @@
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/*-
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* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995
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* The Regents of the University of California. All rights reserved.
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* The Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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@ -27,37 +28,9 @@
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* SUCH DAMAGE.
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*
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* @(#)tcp_sack.c 8.12 (Berkeley) 5/24/95
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* $FreeBSD$
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*/
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/*-
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* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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||||
* modification, are permitted provided that the following conditions
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||||
* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @@(#)COPYRIGHT 1.1 (NRL) 17 January 1995
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*
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* NRL grants permission for redistribution and use in source and binary
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@ -96,6 +69,10 @@
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* official policies, either expressed or implied, of the US Naval
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* Research Laboratory (NRL).
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_inet.h"
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#include "opt_inet6.h"
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#include "opt_tcpdebug.h"
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@ -168,8 +145,8 @@ SYSCTL_INT(_net_inet_tcp_sack, OID_AUTO, globalholes, CTLFLAG_RD,
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"Global number of TCP SACK holes currently allocated");
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/*
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* This function is called upon receipt of new valid data (while not in header
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* prediction mode), and it updates the ordered list of sacks.
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* This function is called upon receipt of new valid data (while not in
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* header prediction mode), and it updates the ordered list of sacks.
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*/
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void
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tcp_update_sack_list(struct tcpcb *tp, tcp_seq rcv_start, tcp_seq rcv_end)
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@ -185,7 +162,7 @@ tcp_update_sack_list(struct tcpcb *tp, tcp_seq rcv_start, tcp_seq rcv_end)
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INP_LOCK_ASSERT(tp->t_inpcb);
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/* Check arguments */
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/* Check arguments. */
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KASSERT(SEQ_LT(rcv_start, rcv_end), ("rcv_start < rcv_end"));
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/* SACK block for the received segment. */
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@ -193,9 +170,9 @@ tcp_update_sack_list(struct tcpcb *tp, tcp_seq rcv_start, tcp_seq rcv_end)
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head_blk.end = rcv_end;
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/*
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* Merge updated SACK blocks into head_blk, and
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* save unchanged SACK blocks into saved_blks[].
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* num_saved will have the number of the saved SACK blocks.
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* Merge updated SACK blocks into head_blk, and save unchanged SACK
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* blocks into saved_blks[]. num_saved will have the number of the
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* saved SACK blocks.
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*/
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num_saved = 0;
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for (i = 0; i < tp->rcv_numsacks; i++) {
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@ -208,8 +185,8 @@ tcp_update_sack_list(struct tcpcb *tp, tcp_seq rcv_start, tcp_seq rcv_end)
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} else if (SEQ_LEQ(head_blk.start, end) &&
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SEQ_GEQ(head_blk.end, start)) {
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/*
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* Merge this SACK block into head_blk.
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* This SACK block itself will be discarded.
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* Merge this SACK block into head_blk. This SACK
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* block itself will be discarded.
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*/
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if (SEQ_GT(head_blk.start, start))
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head_blk.start = start;
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@ -231,8 +208,8 @@ tcp_update_sack_list(struct tcpcb *tp, tcp_seq rcv_start, tcp_seq rcv_end)
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num_head = 0;
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if (SEQ_GT(head_blk.start, tp->rcv_nxt)) {
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/*
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* The received data segment is an out-of-order segment.
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* Put head_blk at the top of SACK list.
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* The received data segment is an out-of-order segment. Put
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* head_blk at the top of SACK list.
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*/
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tp->sackblks[0] = head_blk;
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num_head = 1;
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@ -303,6 +280,7 @@ tcp_sackhole_alloc(struct tcpcb *tp, tcp_seq start, tcp_seq end)
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static void
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tcp_sackhole_free(struct tcpcb *tp, struct sackhole *hole)
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{
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uma_zfree(sack_hole_zone, hole);
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tp->snd_numholes--;
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@ -326,7 +304,7 @@ tcp_sackhole_insert(struct tcpcb *tp, tcp_seq start, tcp_seq end,
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if (hole == NULL)
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return NULL;
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/* Insert the new SACK hole into scoreboard */
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/* Insert the new SACK hole into scoreboard. */
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if (after != NULL)
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TAILQ_INSERT_AFTER(&tp->snd_holes, after, hole, scblink);
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else
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@ -345,6 +323,7 @@ tcp_sackhole_insert(struct tcpcb *tp, tcp_seq start, tcp_seq end,
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static void
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tcp_sackhole_remove(struct tcpcb *tp, struct sackhole *hole)
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{
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/* Update SACK hint. */
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if (tp->sackhint.nexthole == hole)
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tp->sackhint.nexthole = TAILQ_NEXT(hole, scblink);
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@ -380,8 +359,8 @@ tcp_sack_doack(struct tcpcb *tp, struct tcpopt *to, tcp_seq th_ack)
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sack_blocks[num_sack_blks++].end = th_ack;
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}
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/*
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* Append received valid SACK blocks to sack_blocks[], but only
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* if we received new blocks from the other side.
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* Append received valid SACK blocks to sack_blocks[], but only if we
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* received new blocks from the other side.
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*/
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if (to->to_flags & TOF_SACK) {
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for (i = 0; i < to->to_nsacks; i++) {
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@ -399,16 +378,16 @@ tcp_sack_doack(struct tcpcb *tp, struct tcpopt *to, tcp_seq th_ack)
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}
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}
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/*
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* Return if SND.UNA is not advanced and no valid SACK block
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* is received.
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* Return if SND.UNA is not advanced and no valid SACK block is
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* received.
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*/
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if (num_sack_blks == 0)
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return;
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/*
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* Sort the SACK blocks so we can update the scoreboard
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* with just one pass. The overhead of sorting upto 4+1 elements
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* is less than making upto 4+1 passes over the scoreboard.
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* Sort the SACK blocks so we can update the scoreboard with just one
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* pass. The overhead of sorting upto 4+1 elements is less than
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* making upto 4+1 passes over the scoreboard.
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*/
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for (i = 0; i < num_sack_blks; i++) {
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for (j = i + 1; j < num_sack_blks; j++) {
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@ -423,15 +402,17 @@ tcp_sack_doack(struct tcpcb *tp, struct tcpopt *to, tcp_seq th_ack)
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/*
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* Empty scoreboard. Need to initialize snd_fack (it may be
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* uninitialized or have a bogus value). Scoreboard holes
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* (from the sack blocks received) are created later below (in
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* the logic that adds holes to the tail of the scoreboard).
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* (from the sack blocks received) are created later below
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* (in the logic that adds holes to the tail of the
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* scoreboard).
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*/
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tp->snd_fack = SEQ_MAX(tp->snd_una, th_ack);
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/*
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* In the while-loop below, incoming SACK blocks (sack_blocks[])
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* and SACK holes (snd_holes) are traversed from their tails with
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* just one pass in order to reduce the number of compares especially
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* when the bandwidth-delay product is large.
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* In the while-loop below, incoming SACK blocks (sack_blocks[]) and
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* SACK holes (snd_holes) are traversed from their tails with just
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* one pass in order to reduce the number of compares especially when
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* the bandwidth-delay product is large.
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*
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* Note: Typically, in the first RTT of SACK recovery, the highest
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* three or four SACK blocks with the same ack number are received.
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* In the second RTT, if retransmitted data segments are not lost,
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@ -441,11 +422,10 @@ tcp_sack_doack(struct tcpcb *tp, struct tcpopt *to, tcp_seq th_ack)
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sblkp = &sack_blocks[num_sack_blks - 1]; /* Last SACK block */
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if (SEQ_LT(tp->snd_fack, sblkp->start)) {
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/*
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* The highest SACK block is beyond fack.
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* Append new SACK hole at the tail.
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* If the second or later highest SACK blocks are also
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* beyond the current fack, they will be inserted by
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* way of hole splitting in the while-loop below.
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* The highest SACK block is beyond fack. Append new SACK
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* hole at the tail. If the second or later highest SACK
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* blocks are also beyond the current fack, they will be
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* inserted by way of hole splitting in the while-loop below.
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*/
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temp = tcp_sackhole_insert(tp, tp->snd_fack,sblkp->start,NULL);
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if (temp != NULL) {
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@ -456,10 +436,10 @@ tcp_sack_doack(struct tcpcb *tp, struct tcpopt *to, tcp_seq th_ack)
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/*
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* We failed to add a new hole based on the current
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* sack block. Skip over all the sack blocks that
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* fall completely to the right of snd_fack and proceed
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* to trim the scoreboard based on the remaining sack
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* blocks. This also trims the scoreboard for th_ack
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* (which is sack_blocks[0]).
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* fall completely to the right of snd_fack and
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* proceed to trim the scoreboard based on the
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* remaining sack blocks. This also trims the
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* scoreboard for th_ack (which is sack_blocks[0]).
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*/
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while (sblkp >= sack_blocks &&
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SEQ_LT(tp->snd_fack, sblkp->start))
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@ -471,9 +451,10 @@ tcp_sack_doack(struct tcpcb *tp, struct tcpopt *to, tcp_seq th_ack)
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} else if (SEQ_LT(tp->snd_fack, sblkp->end))
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/* fack is advanced. */
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tp->snd_fack = sblkp->end;
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/* We must have at least one SACK hole in scoreboard */
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KASSERT(!TAILQ_EMPTY(&tp->snd_holes), ("SACK scoreboard must not be empty"));
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cur = TAILQ_LAST(&tp->snd_holes, sackhole_head); /* Last SACK hole */
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/* We must have at least one SACK hole in scoreboard. */
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KASSERT(!TAILQ_EMPTY(&tp->snd_holes),
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("SACK scoreboard must not be empty"));
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cur = TAILQ_LAST(&tp->snd_holes, sackhole_head); /* Last SACK hole. */
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/*
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* Since the incoming sack blocks are sorted, we can process them
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* making one sweep of the scoreboard.
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@ -481,63 +462,64 @@ tcp_sack_doack(struct tcpcb *tp, struct tcpopt *to, tcp_seq th_ack)
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while (sblkp >= sack_blocks && cur != NULL) {
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if (SEQ_GEQ(sblkp->start, cur->end)) {
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/*
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* SACKs data beyond the current hole.
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* Go to the previous sack block.
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* SACKs data beyond the current hole. Go to the
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* previous sack block.
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*/
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sblkp--;
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continue;
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}
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if (SEQ_LEQ(sblkp->end, cur->start)) {
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/*
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* SACKs data before the current hole.
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* Go to the previous hole.
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* SACKs data before the current hole. Go to the
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* previous hole.
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*/
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cur = TAILQ_PREV(cur, sackhole_head, scblink);
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continue;
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}
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tp->sackhint.sack_bytes_rexmit -= (cur->rxmit - cur->start);
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KASSERT(tp->sackhint.sack_bytes_rexmit >= 0,
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("sackhint bytes rtx >= 0"));
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("sackhint bytes rtx >= 0"));
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if (SEQ_LEQ(sblkp->start, cur->start)) {
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/* Data acks at least the beginning of hole */
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/* Data acks at least the beginning of hole. */
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if (SEQ_GEQ(sblkp->end, cur->end)) {
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/* Acks entire hole, so delete hole */
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/* Acks entire hole, so delete hole. */
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temp = cur;
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cur = TAILQ_PREV(cur, sackhole_head, scblink);
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tcp_sackhole_remove(tp, temp);
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/*
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* The sack block may ack all or part of the next
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* hole too, so continue onto the next hole.
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* The sack block may ack all or part of the
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* next hole too, so continue onto the next
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* hole.
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*/
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continue;
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} else {
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/* Move start of hole forward */
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/* Move start of hole forward. */
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cur->start = sblkp->end;
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cur->rxmit = SEQ_MAX(cur->rxmit, cur->start);
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}
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} else {
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/* Data acks at least the end of hole */
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/* Data acks at least the end of hole. */
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if (SEQ_GEQ(sblkp->end, cur->end)) {
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/* Move end of hole backward */
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/* Move end of hole backward. */
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cur->end = sblkp->start;
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cur->rxmit = SEQ_MIN(cur->rxmit, cur->end);
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} else {
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/*
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* ACKs some data in middle of a hole; need to
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* split current hole
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* ACKs some data in middle of a hole; need
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* to split current hole
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*/
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temp = tcp_sackhole_insert(tp, sblkp->end,
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cur->end, cur);
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cur->end, cur);
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if (temp != NULL) {
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if (SEQ_GT(cur->rxmit, temp->rxmit)) {
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temp->rxmit = cur->rxmit;
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tp->sackhint.sack_bytes_rexmit
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+= (temp->rxmit
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- temp->start);
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+= (temp->rxmit
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- temp->start);
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}
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cur->end = sblkp->start;
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cur->rxmit = SEQ_MIN(cur->rxmit,
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cur->end);
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cur->end);
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}
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}
|
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}
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@ -573,14 +555,12 @@ tcp_free_sackholes(struct tcpcb *tp)
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}
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/*
|
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* Partial ack handling within a sack recovery episode.
|
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* Keeping this very simple for now. When a partial ack
|
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* is received, force snd_cwnd to a value that will allow
|
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* the sender to transmit no more than 2 segments.
|
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* If necessary, a better scheme can be adopted at a
|
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* later point, but for now, the goal is to prevent the
|
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* sender from bursting a large amount of data in the midst
|
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* of sack recovery.
|
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* Partial ack handling within a sack recovery episode. Keeping this very
|
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* simple for now. When a partial ack is received, force snd_cwnd to a value
|
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* that will allow the sender to transmit no more than 2 segments. If
|
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* necessary, a better scheme can be adopted at a later point, but for now,
|
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* the goal is to prevent the sender from bursting a large amount of data in
|
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* the midst of sack recovery.
|
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*/
|
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void
|
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tcp_sack_partialack(struct tcpcb *tp, struct tcphdr *th)
|
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@ -590,12 +570,11 @@ tcp_sack_partialack(struct tcpcb *tp, struct tcphdr *th)
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INP_LOCK_ASSERT(tp->t_inpcb);
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tcp_timer_activate(tp, TT_REXMT, 0);
|
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tp->t_rtttime = 0;
|
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/* send one or 2 segments based on how much new data was acked */
|
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/* Send one or 2 segments based on how much new data was acked. */
|
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if (((th->th_ack - tp->snd_una) / tp->t_maxseg) > 2)
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num_segs = 2;
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tp->snd_cwnd = (tp->sackhint.sack_bytes_rexmit +
|
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(tp->snd_nxt - tp->sack_newdata) +
|
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num_segs * tp->t_maxseg);
|
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(tp->snd_nxt - tp->sack_newdata) + num_segs * tp->t_maxseg);
|
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if (tp->snd_cwnd > tp->snd_ssthresh)
|
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tp->snd_cwnd = tp->snd_ssthresh;
|
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tp->t_flags |= TF_ACKNOW;
|
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@ -604,7 +583,7 @@ tcp_sack_partialack(struct tcpcb *tp, struct tcphdr *th)
|
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|
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#if 0
|
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/*
|
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* Debug version of tcp_sack_output() that walks the scoreboard. Used for
|
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* Debug version of tcp_sack_output() that walks the scoreboard. Used for
|
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* now to sanity check the hint.
|
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*/
|
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static struct sackhole *
|
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@ -630,20 +609,20 @@ tcp_sack_output_debug(struct tcpcb *tp, int *sack_bytes_rexmt)
|
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|
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/*
|
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* Returns the next hole to retransmit and the number of retransmitted bytes
|
||||
* from the scoreboard. We store both the next hole and the number of
|
||||
* from the scoreboard. We store both the next hole and the number of
|
||||
* retransmitted bytes as hints (and recompute these on the fly upon SACK/ACK
|
||||
* reception). This avoids scoreboard traversals completely.
|
||||
* reception). This avoids scoreboard traversals completely.
|
||||
*
|
||||
* The loop here will traverse *at most* one link. Here's the argument.
|
||||
* For the loop to traverse more than 1 link before finding the next hole to
|
||||
* retransmit, we would need to have at least 1 node following the current hint
|
||||
* with (rxmit == end). But, for all holes following the current hint,
|
||||
* (start == rxmit), since we have not yet retransmitted from them. Therefore,
|
||||
* in order to traverse more 1 link in the loop below, we need to have at least
|
||||
* one node following the current hint with (start == rxmit == end).
|
||||
* But that can't happen, (start == end) means that all the data in that hole
|
||||
* has been sacked, in which case, the hole would have been removed from the
|
||||
* scoreboard.
|
||||
* The loop here will traverse *at most* one link. Here's the argument. For
|
||||
* the loop to traverse more than 1 link before finding the next hole to
|
||||
* retransmit, we would need to have at least 1 node following the current
|
||||
* hint with (rxmit == end). But, for all holes following the current hint,
|
||||
* (start == rxmit), since we have not yet retransmitted from them.
|
||||
* Therefore, in order to traverse more 1 link in the loop below, we need to
|
||||
* have at least one node following the current hint with (start == rxmit ==
|
||||
* end). But that can't happen, (start == end) means that all the data in
|
||||
* that hole has been sacked, in which case, the hole would have been removed
|
||||
* from the scoreboard.
|
||||
*/
|
||||
struct sackhole *
|
||||
tcp_sack_output(struct tcpcb *tp, int *sack_bytes_rexmt)
|
||||
@ -680,7 +659,7 @@ tcp_sack_adjust(struct tcpcb *tp)
|
||||
return; /* No holes */
|
||||
if (SEQ_GEQ(tp->snd_nxt, tp->snd_fack))
|
||||
return; /* We're already beyond any SACKed blocks */
|
||||
/*
|
||||
/*-
|
||||
* Two cases for which we want to advance snd_nxt:
|
||||
* i) snd_nxt lies between end of one hole and beginning of another
|
||||
* ii) snd_nxt lies between end of last hole and snd_fack
|
||||
|
||||
Loading…
Reference in New Issue
Block a user