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// 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 <mss 1000,sackOK,nop,nop,nop,wscale 7>
+0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8>
+.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 <sack 7001:8001,nop,nop>
// 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 <sack 3001:4001 7001:8001,nop,nop>
+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 <sack 3001:5001 7001:8001,nop,nop>
+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 3001:5001 7001:9001,nop,nop>
// SACK for 9001:10001.
+.002 < . 1:1(0) ack 1 win 257 <sack 3001:5001 7001:10001,nop,nop>
+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
}%
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