// SPDX-License-Identifier: GPL-2.0 // Test shifting of newly-SACKed ranges onto the previous already-SACKed skb. // This variant tests the case where we mark packets 0-4 lost, then // get a SACK for 3, and then a SACK for 4. `./defaults.sh` // Establish a connection and send 10 MSS. 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1) = 0 +0 < S 0:0(0) win 32792 +0 > S. 0:0(0) ack 1 +.1 < . 1:1(0) ack 1 win 1024 +0 accept(3, ..., ...) = 4 +0 write(4, ..., 10000) = 10000 +0 > P. 1:10001(10000) ack 1 // SACK for 7001:8001. Using RACK we delay the fast retransmit. +.1 < . 1:1(0) ack 1 win 257 // RACK reordering timer +.027 > . 1:1001(1000) ack 1 +0 %{ assert tcpi_ca_state == TCP_CA_Recovery, tcpi_ca_state assert tcpi_lost == 7, tcpi_lost # RACK thinks 1:7001 are lost assert tcpi_reordering == 3, tcpi_reordering }% // SACK for 3001:4001. +.002 < . 1:1(0) ack 1 win 257 +0 > . 1001:2001(1000) ack 1 +0 %{ assert tcpi_lost == 6, tcpi_lost # since 3001:4001 is no longer lost assert tcpi_reordering == 5, tcpi_reordering # 7001:8001 -> 3001:4001 }% // SACK for 4001:5001. // This SACK for an adjacent range causes the sender to // shift the newly-SACKed range onto the previous skb. // It uses the RFC3517 algorithm to mark 1:3001 lost // because >=3 higher-sequence packets are SACKed. +.002 < . 1:1(0) ack 1 win 257 +0 > . 2001:3001(1000) ack 1 +0 %{ assert tcpi_lost == 5,tcpi_lost # SACK/RFC3517 thinks 1:3001 are lost }% // SACK for 8001:9001. +.002 < . 1:1(0) ack 1 win 257 // SACK for 9001:10001. +.002 < . 1:1(0) ack 1 win 257 +0 > . 5001:6001(1000) ack 1 // To simplify clean-up, say we get an ACK for all data. +.1 < . 1:1(0) ack 10001 win 257 +0 %{ assert tcpi_ca_state == TCP_CA_Open, tcpi_ca_state assert tcpi_unacked == 0, tcpi_unacked assert tcpi_sacked == 0, tcpi_sacked assert tcpi_lost == 0, tcpi_lost assert tcpi_retrans == 0, tcpi_retrans }%