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The official Google release of packetdrill
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net-test: packetdrill: add support of tcp option wildcard "wscale *" #75

Open chantra opened 1 year ago

chantra commented 1 year ago

Summary: In current script, we can either specify every tcp option of a packet, or use <...> for "any tcp options". This is not flexible enough, as some script may have requirements for some tcp options; while be flexible with other options.

This patch tries to address this by adding wildcard for option wscale. Specifically, "wscale *" in the tcp option list means any wscale value.

To mark a tcp option in the script as wildcard, we leverage the highest bit of tcp_option->kind, as TCPOPT_WILDCARD (0x80). tcp_option->kind of TCPOPT_WILDCARD | TCPOPT_WINDOW (0x83) means wscale option of any value.

verify_outbound_live_tcp_options() is updated to be able to understand TCPOPT_WILDCARD when set on the script packet and with TCPOPT_WINDOW.

Testing: Using a script that currently fail on my environment with wscale:

$ sudo ./packetdrill/run_all.py -S -v  -L -l
tcp/zerocopy/fastopen-client.pkt
FAIL
[/data/users/chantra/google-packetdrill/gtests/net/tcp/zerocopy/fastopen-client.pkt
(ipv4)]
stdout:
stderr:
fastopen-client.pkt:17: error handling packet: bad value outbound TCP
option 3
script packet:  0.000105 S 0:0(0) <mss 1460,sackOK,TS val 1000 ecr
0,nop,wscale 8,FO,nop,nop>
actual packet:  0.000095 S 0:0(0) win 65535 <mss 1460,sackOK,TS val 1000
ecr 0,nop,wscale 9,FO,nop,nop>
FAIL
[/data/users/chantra/google-packetdrill/gtests/net/tcp/zerocopy/fastopen-client.pkt
(ipv6)]
stdout:
stderr:
fastopen-client.pkt:17: error handling packet: bad value outbound TCP
option 3
script packet:  0.000157 S 0:0(0) <mss 1460,sackOK,TS val 1000 ecr
0,nop,wscale 8,FO,nop,nop>
actual packet:  0.000145 S 0:0(0) win 65535 <mss 1460,sackOK,TS val 1000
ecr 0,nop,wscale 9,FO,nop,nop>
FAIL
[/data/users/chantra/google-packetdrill/gtests/net/tcp/zerocopy/fastopen-client.pkt
(ipv4-mapped-v6)]
stdout:
stderr:
fastopen-client.pkt:17: error handling packet: bad value outbound TCP
option 3
script packet:  0.000118 S 0:0(0) <mss 1460,sackOK,TS val 1000 ecr
0,nop,wscale 8,FO,nop,nop>
actual packet:  0.000106 S 0:0(0) win 65535 <mss 1460,sackOK,TS val 1000
ecr 0,nop,wscale 9,FO,nop,nop>
Ran    3 tests:    0 passing,    3 failing,    0 timed out (2.69 sec):
tcp/zerocopy/fastopen-client.pkt

Changed the wscale to wildcard:

$ diff -ruN tcp/zerocopy/fastopen-client.pkt
tcp/zerocopy/fastopen-client-wscale-wildcard.pkt
--- tcp/zerocopy/fastopen-client.pkt    2023-06-27 18:36:22.956369457
-0700
+++ tcp/zerocopy/fastopen-client-wscale-wildcard.pkt    2023-06-27
18:37:29.306312093 -0700
@@ -14,7 +14,7 @@
    +0 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0
    +0 setsockopt(3, SOL_SOCKET, SO_ZEROCOPY, [1], 4) = 0
    +0 sendto(3, ..., 500, MSG_FASTOPEN|MSG_ZEROCOPY, ..., ...) = -1
EINPROGRESS (Operation now in progress)
-   +0 > S 0:0(0) <mss 1460,sackOK,TS val 1000 ecr 0,nop,wscale
    8,FO,nop,nop>
+   +0 > S 0:0(0) <mss 1460,sackOK,TS val 1000 ecr 0,nop,wscale
    *,FO,nop,nop>
  +.01 < S. 123:123(0) ack 1 win 14600 <mss 940,TS val 2000 ecr
1000,sackOK,nop,wscale 6, FO abcd1234,nop,nop>
    +0 > . 1:1(0) ack 1 <nop,nop,TS val 1001 ecr 2000>

@@ -35,7 +35,7 @@
    +0 fcntl(5, F_SETFL, O_RDWR|O_NONBLOCK) = 0
    +0 setsockopt(5, SOL_SOCKET, SO_ZEROCOPY, [1], 4) = 0
    +0 sendto(5, ..., 500, MSG_FASTOPEN|MSG_ZEROCOPY, ..., ...) = 500
-   +0 > S 0:500(500) <mss 1460,nop,nop,sackOK,nop,wscale 8,FO
    abcd1234,nop,nop>
+   +0 > S 0:500(500) <mss 1460,nop,nop,sackOK,nop,wscale *,FO
    abcd1234,nop,nop>
  +.05 < S. 5678:5678(0) ack 501 win 14600 <mss
1460,nop,nop,sackOK,nop,wscale 6>
    +0 > . 501:501(0) ack 1

and confirmed the test now pass:

$ sudo ./packetdrill/run_all.py -S -v  -L -l
tcp/zerocopy/fastopen-client-wscale-wildcard.pkt
OK
[/data/users/chantra/google-packetdrill/gtests/net/tcp/zerocopy/fastopen-client-wscale-wildcard.pkt
(ipv4)]
stdout:
stderr:
OK
[/data/users/chantra/google-packetdrill/gtests/net/tcp/zerocopy/fastopen-client-wscale-wildcard.pkt
(ipv6)]
stdout:
stderr:
OK
[/data/users/chantra/google-packetdrill/gtests/net/tcp/zerocopy/fastopen-client-wscale-wildcard.pkt
(ipv4-mapped-v6)]
stdout:
stderr:
Ran    3 tests:    3 passing,    0 failing,    0 timed out (7.91 sec):
tcp/zerocopy/fastopen-client-wscale-wildcard.pkt

and also still work properly when the wscale is matching expectations:

$ diff -ruN tcp/zerocopy/fastopen-client.pkt tcp/zerocopy/fastopen-client-correct-wscale.pkt
--- tcp/zerocopy/fastopen-client.pkt    2023-06-27 18:36:22.956369457
-0700
+++ tcp/zerocopy/fastopen-client-correct-wscale.pkt     2023-06-27
18:39:24.630212385 -0700
@@ -14,7 +14,7 @@
    +0 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0
    +0 setsockopt(3, SOL_SOCKET, SO_ZEROCOPY, [1], 4) = 0
    +0 sendto(3, ..., 500, MSG_FASTOPEN|MSG_ZEROCOPY, ..., ...) = -1
EINPROGRESS (Operation now in progress)
-   +0 > S 0:0(0) <mss 1460,sackOK,TS val 1000 ecr 0,nop,wscale
    8,FO,nop,nop>
+   +0 > S 0:0(0) <mss 1460,sackOK,TS val 1000 ecr 0,nop,wscale
    9,FO,nop,nop>
  +.01 < S. 123:123(0) ack 1 win 14600 <mss 940,TS val 2000 ecr
1000,sackOK,nop,wscale 6, FO abcd1234,nop,nop>
    +0 > . 1:1(0) ack 1 <nop,nop,TS val 1001 ecr 2000>

@@ -35,7 +35,7 @@
    +0 fcntl(5, F_SETFL, O_RDWR|O_NONBLOCK) = 0
    +0 setsockopt(5, SOL_SOCKET, SO_ZEROCOPY, [1], 4) = 0
    +0 sendto(5, ..., 500, MSG_FASTOPEN|MSG_ZEROCOPY, ..., ...) = 500
-   +0 > S 0:500(500) <mss 1460,nop,nop,sackOK,nop,wscale 8,FO
    abcd1234,nop,nop>
+   +0 > S 0:500(500) <mss 1460,nop,nop,sackOK,nop,wscale 9,FO
    abcd1234,nop,nop>
  +.05 < S. 5678:5678(0) ack 501 win 14600 <mss
1460,nop,nop,sackOK,nop,wscale 6>
    +0 > . 501:501(0) ack 1

with

$ sudo ./packetdrill/run_all.py -S -v  -L -l tcp/zerocopy/fastopen-client-correct-wscale.pkt
OK
[/data/users/chantra/google-packetdrill/gtests/net/tcp/zerocopy/fastopen-client-correct-wscale.pkt
(ipv4)]
stdout:
stderr:
OK
[/data/users/chantra/google-packetdrill/gtests/net/tcp/zerocopy/fastopen-client-correct-wscale.pkt
(ipv6)]
stdout:
stderr:
OK
[/data/users/chantra/google-packetdrill/gtests/net/tcp/zerocopy/fastopen-client-correct-wscale.pkt
(ipv4-mapped-v6)]
stdout:
stderr:
Ran    3 tests:    3 passing,    0 failing,    0 timed out (8.16 sec):
tcp/zerocopy/fastopen-client-correct-wscale.pkt

Also comfirmed that wscale wildcard would not cause and option which has 0x80 set to pass.

For instance with:

$ diff -ruN tcp/fastopen/server/simple2.pkt
tcp/fastopen/server/simple2-wscale.pkt
--- tcp/fastopen/server/simple2.pkt     2023-06-27 17:28:58.547790456
-0700
+++ tcp/fastopen/server/simple2-wscale.pkt      2023-06-27
19:00:49.460036441 -0700
@@ -22,7 +22,7 @@

    +0 < S 9873242:9873242(0) win 10000 <mss 1012,FOEXP,sackOK,TS val 1
ecr 0,nop,wscale 7>
 // Test the cookie is as expected by encoding both IPs w/ key
-   +0 > S. 0:0(0) ack 9873243 <mss 1460,sackOK,TS val 10000 ecr
    1,nop,wscale 8, FOEXP 1313a2da994a0951>
+   +0 > S. 0:0(0) ack 9873243 <mss 1460,sackOK,TS val 10000 ecr
    1,nop,wscale *, FOEXP f49b0ef989d9f624>
   +.1 < . 1:1(0) ack 1 win 257 <nop,nop,TS val 2 ecr 10000>
    +0 accept(3, ..., ...) = 4
    +0 close(4) = 0
@@ -38,8 +38,8 @@
    +0 bind(3, ..., ...) = 0
    +0 listen(3, 1) = 0

- +.05 < S 19124022:19125022(1000) win 10000 <mss 1012,FOEXP
  1313a2da994a0951,sackOK,TS val 10 ecr 0,nop,wscale 7>
-   +0 > S. 0:0(0) ack 19125023 <mss 1460,sackOK,TS val 100000 ecr
    10,nop,wscale 8>
+ +.05 < S 19124022:19125022(1000) win 10000 <mss 1012,FOEXP
  f49b0ef989d9f624,sackOK,TS val 10 ecr 0,nop,wscale 7>
+   +0 > S. 0:0(0) ack 19125023 <mss 1460,sackOK,TS val 100000 ecr
    10,nop,wscale 9>
    +0 accept(3, ..., ...) = 4

 `/tmp/sysctl_restore_${PPID}.sh`

The test fails at handling Fast Open Experimental

simple2-wscale.pkt:25: error handling packet: bad value outbound TCP
option 254
script packet:  0.000163 S. 0:0(0) ack 9873243 <mss 1460,sackOK,TS val
10000 ecr 1,nop,wscale *,FOEXP f49b0ef989d9f624>
actual packet:  0.000159 S. 0:0(0) ack 9873243 win 65535 <mss
1460,sackOK,TS val 10000 ecr 1,nop,wscale 9,FOEXP 792f542eed8979b8>
OK
[/data/users/chantra/google-packetdrill/gtests/net/tcp/fastopen/server/simple2-wscale.pkt
(ipv4-mapped-v6)]
google-cla[bot] commented 1 year ago

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chantra commented 1 year ago

@nealcardwell I forced pushed the change with my corp email address. CLA bot is now happy.