1// SPDX-License-Identifier: GPL-2.0 2// Test shifting of newly-SACKed ranges onto the previous already-SACKed skb. 3// This variant tests the case where we mark packets 0-4 lost, then 4// get a SACK for 3, and then a SACK for 4. 5 6`./defaults.sh` 7 8// Establish a connection and send 10 MSS. 9 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 10 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 11 +0 bind(3, ..., ...) = 0 12 +0 listen(3, 1) = 0 13 14 +0 < S 0:0(0) win 32792 <mss 1000,sackOK,nop,nop,nop,wscale 7> 15 +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8> 16 +.1 < . 1:1(0) ack 1 win 1024 17 +0 accept(3, ..., ...) = 4 18 19 +0 write(4, ..., 10000) = 10000 20 +0 > P. 1:10001(10000) ack 1 21 22// SACK for 7001:8001. Using RACK we delay the fast retransmit. 23 +.1 < . 1:1(0) ack 1 win 257 <sack 7001:8001,nop,nop> 24// RACK reordering timer 25+.027 > . 1:1001(1000) ack 1 26 +0 %{ 27assert tcpi_ca_state == TCP_CA_Recovery, tcpi_ca_state 28assert tcpi_lost == 7, tcpi_lost # RACK thinks 1:7001 are lost 29assert tcpi_reordering == 3, tcpi_reordering 30}% 31 32// SACK for 3001:4001. 33+.002 < . 1:1(0) ack 1 win 257 <sack 3001:4001 7001:8001,nop,nop> 34 +0 > . 1001:2001(1000) ack 1 35 +0 %{ 36assert tcpi_lost == 6, tcpi_lost # since 3001:4001 is no longer lost 37assert tcpi_reordering == 5, tcpi_reordering # 7001:8001 -> 3001:4001 38}% 39 40// SACK for 4001:5001. 41// This SACK for an adjacent range causes the sender to 42// shift the newly-SACKed range onto the previous skb. 43// It uses the RFC3517 algorithm to mark 1:3001 lost 44// because >=3 higher-sequence packets are SACKed. 45+.002 < . 1:1(0) ack 1 win 257 <sack 3001:5001 7001:8001,nop,nop> 46 +0 > . 2001:3001(1000) ack 1 47 +0 %{ 48assert tcpi_lost == 5,tcpi_lost # SACK/RFC3517 thinks 1:3001 are lost 49}% 50 51// SACK for 8001:9001. 52+.002 < . 1:1(0) ack 1 win 257 <sack 3001:5001 7001:9001,nop,nop> 53 54// SACK for 9001:10001. 55+.002 < . 1:1(0) ack 1 win 257 <sack 3001:5001 7001:10001,nop,nop> 56 +0 > . 5001:6001(1000) ack 1 57 58// To simplify clean-up, say we get an ACK for all data. 59 +.1 < . 1:1(0) ack 10001 win 257 60 +0 %{ 61assert tcpi_ca_state == TCP_CA_Open, tcpi_ca_state 62assert tcpi_unacked == 0, tcpi_unacked 63assert tcpi_sacked == 0, tcpi_sacked 64assert tcpi_lost == 0, tcpi_lost 65assert tcpi_retrans == 0, tcpi_retrans 66}% 67