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selftests/net: packetdrill: import tcp/ecn, tcp/close, tcp/sack, tcp/…
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…tcp_info

Same as initial tests, import verbatim from
github.com/google/packetdrill, aside from:

- update `source ./defaults.sh` path to adjust for flat dir
- add SPDX headers
- remove author statements if any
- drop blank lines at EOF

Same test process as previous tests. Both with and without debug mode.
Recording the steps once:

make mrproper
vng --build \
--config tools/testing/selftests/net/packetdrill/config \
--config kernel/configs/debug.config
vng -v --run . --user root --cpus 4 -- \
make -C tools/testing/selftests TARGETS=net/packetdrill run_tests

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Soham Chakradeo <sohamch@google.com>
Link: https://patch.msgid.link/20241217185203.297935-2-sohamch.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Soham Chakradeo authored and Jakub Kicinski committed Dec 18, 2024
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// SPDX-License-Identifier: GPL-2.0
// Test basic connection teardown where local process closes first:
// the local process calls close() first, so we send a FIN, and receive an ACK.
// Then we receive a FIN and ACK it.

`./defaults.sh`

0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
+.01...0.011 connect(3, ..., ...) = 0
+0 > S 0:0(0) <...>
+0 < S. 0:0(0) ack 1 win 32768 <mss 1000,nop,wscale 6,nop,nop,sackOK>
+0 > . 1:1(0) ack 1

+0 write(3, ..., 1000) = 1000
+0 > P. 1:1001(1000) ack 1
+0 < . 1:1(0) ack 1001 win 257

+0 close(3) = 0
+0 > F. 1001:1001(0) ack 1
+0 < . 1:1(0) ack 1002 win 257

+0 < F. 1:1(0) ack 1002 win 257
+0 > . 1002:1002(0) ack 2
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// SPDX-License-Identifier: GPL-2.0
// Test to make sure no RST is being sent when close()
// is called on a socket with SYN_SENT state.

`./defaults.sh`

0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
+0 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0

+0 connect(3, ..., ...) = -1 EINPROGRESS (Operation now in progress)
+0 > S 0:0(0) <...>

// Application decideds to close the socket in SYN_SENT state
// Make sure no RST is sent after close().
+0 close(3) = 0

// Receive syn-ack to trigger the send side packet examination:
// If a RESET were sent right after close(), it would have failed with
// a mismatched timestamp.
+.1 < S. 0:0(0) ack 1 win 32000 <mss 1460,nop,wscale 7>
+0 > R 1:1(0)
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// SPDX-License-Identifier: GPL-2.0
// Verify behavior for the sequence: remote side sends FIN, then we close().
// Since the remote side (client) closes first, we test our LAST_ACK code path.

`./defaults.sh`

// Initialize a server socket.
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>
+0 < . 1:1(0) ack 1 win 257

+0 accept(3, ..., ...) = 4

// Client closes first.
+.01 < F. 1:1(0) ack 1 win 257
+0 > . 1:1(0) ack 2

// App notices that client closed.
+0 read(4, ..., 1000) = 0

// Then we close.
+.01 close(4) = 0
+0 > F. 1:1(0) ack 2

// Client ACKs our FIN.
+.01 < . 2:2(0) ack 2 win 257

// Verify that we send RST in response to any incoming segments
// (because the kernel no longer has any record of this socket).
+.01 < . 2:2(0) ack 2 win 257
+0 > R 2:2(0)
21 changes: 21 additions & 0 deletions tools/testing/selftests/net/packetdrill/tcp_ecn_ecn-uses-ect0.pkt
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// SPDX-License-Identifier: GPL-2.0
// Test ECN: verify that Linux TCP ECN sending code uses ECT0 (not ECT1).
//
`./defaults.sh
sysctl -q net.ipv4.tcp_ecn=1 # fully enabled
`

// Initialize connection
0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 4

// ECN handshake: send EW flags in SYN packet, E flag in SYN-ACK response
+.002 ... 0.004 connect(4, ..., ...) = 0

+0 > SEW 0:0(0) <mss 1460,sackOK,TS val 100 ecr 0,nop,wscale 8>
+.002 < SE. 0:0(0) ack 1 win 32767 <mss 1000,nop,wscale 6,nop,nop,sackOK>
+0 > . 1:1(0) ack 1

// Write 1 MSS.
+.002 write(4, ..., 1000) = 1000
// Send 1 MSS with ect0.
+0 > [ect0] P. 1:1001(1000) ack 1
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// SPDX-License-Identifier: GPL-2.0
// Verify that setsockopt calls that force a route refresh do not
// cause problems matching SACKs with packets in the write queue.
// This variant tests IP_TOS.

`./defaults.sh`

// Establish a connection.
0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
+0 setsockopt(3, SOL_IP, IP_MTU_DISCOVER, [IP_PMTUDISC_DONT], 1) = 0
+0...0.010 connect(3, ..., ...) = 0

+0 > S 0:0(0) <mss 1460,sackOK,TS val 100 ecr 0,nop,wscale 8>
+.01 < S. 0:0(0) ack 1 win 65535 <mss 1460,nop,wscale 2,nop,nop,sackOK>
+0 > . 1:1(0) ack 1

+.01 write(3, ..., 5840) = 5840
+0 > P. 1:5841(5840) ack 1
+.01 < . 1:1(0) ack 5841 win 65535

+.01 write(3, ..., 5840) = 5840
+0 > P. 5841:11681(5840) ack 1
+.01 < . 1:1(0) ack 11681 win 65535

+.01 write(3, ..., 14600) = 14600
+0 > P. 11681:26281(14600) ack 1

// Try the socket option that we know can force a route refresh.
+0 setsockopt(3, SOL_IP, IP_TOS, [4], 1) = 0
// Then revert to avoid routing/mangling/etc implications of that setting.
+0 setsockopt(3, SOL_IP, IP_TOS, [0], 1) = 0

// Verify that we do not retransmit the SACKed segments.
+.01 < . 1:1(0) ack 13141 win 65535 <sack 16061:17521 20441:26281,nop,nop>
+0 > . 13141:16061(2920) ack 1
+0 > P. 17521:20441(2920) ack 1
+.01 < . 1:1(0) ack 26281 win 65535
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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 non-FACK SACK with SACKs coming in the order
// 2 6 8 3 9, to test what happens when we get a new SACKed range
// (for packet 3) that is on the right of an existing SACKed range
// (for packet 2).

`./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

+.1 < . 1:1(0) ack 1 win 257 <sack 2001:3001,nop,nop>
+.001 < . 1:1(0) ack 1 win 257 <sack 2001:3001 6001:7001,nop,nop>
+.001 < . 1:1(0) ack 1 win 257 <sack 2001:3001 6001:7001 8001:9001,nop,nop>

// 3 SACKed packets, so we enter Fast Recovery.
+0 > . 1:1001(1000) ack 1
+0 %{ assert tcpi_ca_state == TCP_CA_Recovery, tcpi_ca_state }%
+0 %{ assert tcpi_lost == 6, tcpi_lost }%

// SACK for 3001:4001.
// This SACK for an adjacent range causes the sender to
// shift the newly-SACKed range onto the previous skb.
+.007 < . 1:1(0) ack 1 win 257 <sack 2001:4001 6001:7001 8001:9001,nop,nop>
+0 > . 1001:2001(1000) ack 1
+0 %{ assert tcpi_lost == 5, tcpi_lost }%
+0 %{ assert tcpi_reordering == 6, tcpi_reordering }% // 8001:9001 -> 3001:4001 is 6

// SACK for 9001:10001.
+.01 < . 1:1(0) ack 1 win 257 <sack 2001:4001 6001:7001 8001:10001,nop,nop>
+0 %{ assert tcpi_lost == 5, tcpi_lost }%

// ACK for 1:1001 as packets from t=0.303 arrive.
+.083 < . 1:1(0) ack 1001 win 257 <sack 2001:4001 6001:7001 8001:10001,nop,nop>
+0 %{ assert tcpi_lost == 4,tcpi_lost }%

// ACK for 1:4001 as packets from t=0.310 arrive.
+.017 < . 1:1(0) ack 4001 win 257 <sack 6001:7001 8001:10001,nop,nop>
+0 %{ assert tcpi_lost == 3,tcpi_lost }%

// ACK for 1:7001 as packets from t=0.320 arrive.
+.01 < . 1:1(0) ack 7001 win 257 <sack 8001:10001,nop,nop>

// ACK for all data as packets from t=0.403 arrive.
+.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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// 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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// 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 5, and then a SACK for 6.

`./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 a fast retransmit.
+.1 < . 1:1(0) ack 1 win 257 <sack 7001:8001,nop,nop>
+.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 5001:6001.
+0 < . 1:1(0) ack 1 win 257 <sack 5001:6001 7001:8001,nop,nop>
+0 > . 1001:2001(1000) ack 1
+0 %{
assert tcpi_lost == 6, tcpi_lost
assert tcpi_reordering == 3, tcpi_reordering # 7001:8001 -> 5001:6001 is 3
}%

// SACK for 6001:7001.
// This SACK for an adjacent range causes the sender to
// shift the newly-SACKed range onto the previous skb.
+0 < . 1:1(0) ack 1 win 257 <sack 5001:8001,nop,nop>
+0 > . 2001:3001(1000) ack 1
+0 %{ assert tcpi_lost == 5, tcpi_lost }%

// SACK for 8001:9001.
+0 < . 1:1(0) ack 1 win 257 <sack 5001:9001,nop,nop>
+0 > . 3001:4001(1000) ack 1

// SACK for 9001:10001.
+0 < . 1:1(0) ack 1 win 257 <sack 5001:10001,nop,nop>
+0 > . 4001:5001(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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// SPDX-License-Identifier: GPL-2.0
// Test tcpi_last_data_recv for active session
`./defaults.sh`

// Create a socket and set it to non-blocking.
+0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
+0 fcntl(3, F_GETFL) = 0x2 (flags O_RDWR)
+0 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0

+0 connect(3, ..., ...) = -1 EINPROGRESS (Operation now in progress)
+0 > S 0:0(0) <mss 1460,sackOK,TS val 100 ecr 0,nop,wscale 8>
+.030 < S. 0:0(0) ack 1 win 10000 <mss 1000,sackOK,nop,nop,nop,wscale 8>
+0 > . 1:1(0) ack 1

+1 %{ assert 990 <= tcpi_last_data_recv <= 1010, tcpi_last_data_recv }%

+0 < . 1:1001(1000) ack 1 win 300
+0 > . 1:1(0) ack 1001

+0 %{ assert tcpi_last_data_recv <= 10, tcpi_last_data_recv }%
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