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packetdrill segfault #23

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cpaasch opened this issue May 25, 2014 · 3 comments
Closed

packetdrill segfault #23

cpaasch opened this issue May 25, 2014 · 3 comments

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@cpaasch
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cpaasch commented May 25, 2014

I have the following segfault (seen in dmesg):

934.129310] packetdrill[1530]: segfault at 8 ip 080749ba sp bfb02230 error 4 in packetdrill[8048000+1e3000]

with the script:

0       `sysctl -w net.ipv4.tcp_keepalive_intvl=1`
+0      `sysctl -w net.ipv4.tcp_keepalive_probes=5`
+0      `sysctl -w net.ipv4.tcp_keepalive_time=10`
+0      `ip tcp_metrics flush`

+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      setsockopt(3, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0

+0      < S 0:0(0) win 32792 <mss 1460,mp_capable a> sock(3)
+0      > S. 0:0(0) ack 1 <mss 1460,mp_capable b> sock(3)
+0      < . 1:1(0) ack 1 win 29200 <mp_capable a b> sock(3)

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

/* Client send 1000 bytes */
+0      < . 1:1001(1000) ack 1 win 32792 <dss dack4 dsn4> sock(4)
+0      > . 1:1(0) ack 1001 <dss dack4> sock(4)

+0      read(4, ..., 1000) = 1000

/* establish an additional subflow */
+0      socket(..., SOCK_STREAM, IPPROTO_TCP) = 5
+0      setsockopt(5, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
+0      bind(5, {sa_family = AF_INET, sin_port = htons(13001), sin_addr = inet_addr("192.168.0.1")}, ...) = 0
+0      listen(5,1) = 0

+0      < S 0:0(0) win 32792 <mss 1460,mp_join_syn backup=0 address_id=0 token=sha1_32(b)> sock(5)
+0      > S. 0:0(0) ack 1 <mss 1460,mp_join_syn_ack backup=0 address_id=0 sender_hmac=trunc_l64_hmac(key_b key_a) > sock(5)
+0.1    < . 1:1(0) ack 1 win 32792 <mp_join_ack sender_hmac=full_160_hmac(key_a key_b)> sock(5)
+0      > . 1:1(0) ack 1 <...> sock(6)

+0      mp_join_accept(5) = 6

/* Keepalives are sent on all subflows */
+9.9    > . 0:0(0) ack 1 <dss dack4> sock(6)
+0      > . 0:0(0) ack 1001 <dss dack4> sock(4)
/* And repeat the probe every 3 seconds if there are no response. */
+1      > . 0:0(0) ack 1 <dss dack4> sock(6)
+0      > . 0:0(0) ack 1001 <dss dack4> sock(4)
+1      > . 0:0(0) ack 1 <dss dack4> sock(6)
+0      > . 0:0(0) ack 1001 <dss dack4> sock(4)
+1      > . 0:0(0) ack 1 <dss dack4> sock(6)
+0      > . 0:0(0) ack 1001 <dss dack4> sock(4)
+1      > . 0:0(0) ack 1 <dss dack4> sock(6)
+0      > . 0:0(0) ack 1001 <dss dack4> sock(4)

/* should fastclose */
+1      > . 1:1(0) ack 1001 <mp_fastclose> sock(4)
+0      > R. 1:1(0) ack 1 <dss dack4> sock(6)
+0      < R. 1001:1001(0) ack 1 win 32792 sock(4)

+0.1    `sysctl -w net.ipv4.tcp_keepalive_intvl=75`
+0      `sysctl -w net.ipv4.tcp_keepalive_probes=9`
+0      `sysctl -w net.ipv4.tcp_keepalive_time=7200`

Seems to happen when it sends (or receives) the reset at the end.
@redward
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redward commented May 26, 2014

I got the next message when I run it:

net.ipv4.tcp_keepalive_intvl = 1
net.ipv4.tcp_keepalive_probes = 5
net.ipv4.tcp_keepalive_time = 10
Object "tcp_metrics" is unknown, try "ip help".
examples/tests/bugs/reset_seg_fault.pkt:4: error executing `ip tcp_metrics flush` command: non-zero status 1

@cpaasch
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cpaasch commented May 27, 2014

Just remove the 'ip tcp_metrics flush' command from the script.

@redward
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redward commented Jul 7, 2014

This issue is now corrected. I didn't close it at right time, sorry.
The example I modified to expect the right socket is as following:

0       `sysctl -w net.ipv4.tcp_keepalive_intvl=1`
+0      `sysctl -w net.ipv4.tcp_keepalive_probes=5`
+0      `sysctl -w net.ipv4.tcp_keepalive_time=10`
+0      `ip tcp_metrics flush`

+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      setsockopt(3, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0

+0      < S 0:0(0) win 32792 <mss 1460,mp_capable a> sock(3)
+0      > S. 0:0(0) ack 1 <mss 1460,mp_capable b> sock(3)
+0      < . 1:1(0) ack 1 win 29200 <mp_capable a b> sock(3)

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

/* Client send 1000 bytes */
+0      < . 1:1001(1000) ack 1 win 32792 <dss dack4 dsn4> sock(4)
+0      > . 1:1(0) ack 1001 <dss dack4> sock(4)

+0      read(4, ..., 1000) = 1000

/* establish an additional subflow */
+0      socket(..., SOCK_STREAM, IPPROTO_TCP) = 5
+0      setsockopt(5, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
+0      bind(5, {sa_family = AF_INET, sin_port = htons(13001), sin_addr = inet_addr("192.168.0.1")}, ...) = 0
+0      listen(5,1) = 0

+0      < S 0:0(0) win 32792 <mss 1460,mp_join_syn backup=0 address_id=0 token=sha1_32(b)> sock(5)
+0      > S. 0:0(0) ack 1 <mss 1460,mp_join_syn_ack backup=0 address_id=0 sender_hmac=trunc_l64_hmac(key_b key_a) > sock(5)
+0.1    < . 1:1(0) ack 1 win 32792 <mp_join_ack sender_hmac=full_160_hmac(key_a key_b)> sock(5)
+0      > . 1:1(0) ack 1 <...> sock(6)

+0      mp_join_accept(5) = 6

/* Keepalives are sent on all subflows */
+9.9      > . 0:0(0) ack 1001 <dss dack4> sock(4)
+0    > . 0:0(0) ack 1 <dss dack4> sock(6)

/* And repeat the probe every 3 seconds if there are no response. */

+1      > . 0:0(0) ack 1001 <dss dack4> sock(4)
+0      > . 0:0(0) ack 1 <dss dack4> sock(6)

+1      > . 0:0(0) ack 1001 <dss dack4> sock(4)
+0      > . 0:0(0) ack 1 <dss dack4> sock(6)

+1      > . 0:0(0) ack 1001 <dss dack4> sock(4)
+0      > . 0:0(0) ack 1 <dss dack4> sock(6)

+1      > . 0:0(0) ack 1001 <dss dack4> sock(4)
+0      > . 0:0(0) ack 1 <dss dack4> sock(6)

/* should fastclose */
+1      > . 1:1(0) ack 1001 <mp_fastclose> sock(4)
+0      > R. 1:1(0) ack 1 <dss dack4> sock(6)
+0      < R. 1001:1001(0) ack 1 win 32792 sock(4)

+0.1    `sysctl -w net.ipv4.tcp_keepalive_intvl=75`
+0      `sysctl -w net.ipv4.tcp_keepalive_probes=9`
+0      `sysctl -w net.ipv4.tcp_keepalive_time=7200`

I ran it with :
$ sudo ./packetdrill examples/corrections/data_fin.pkt --tolerance_usecs=100000 -v

and got

net.ipv4.tcp_keepalive_intvl = 1
net.ipv4.tcp_keepalive_probes = 5
net.ipv4.tcp_keepalive_time = 10
inbound injected packet:  0.025234 S 0:0(0) win 32792 <mss 1460,mp_capable sender_key: 153199658677876282, flags: 129>
outbound sniffed packet:  0.026556 S. 3300006548:3300006548(0) ack 1 win 28800 <mss 1460,mp_capable sender_key: 4858591269394488144, flags: 129>
inbound injected packet:  0.026604 . 1:1(0) ack 3300006549 win 29200 <mp_capable sender_key: 153199658677876282 receiver_key: 4858591269394488144, flags 129>
inbound injected packet:  0.026690 . 1:1001(1000) ack 3300006549 win 32792 <dss dack4 4102526830 dsn4 2070503321 ssn 1 dll 1000 checksum 57145 flags: MA>
outbound sniffed packet:  0.026718 . 3300006549:3300006549(0) ack 1001 win 59000 <dss dack4 2070504321 flags: A>
inbound injected packet:  0.027104 S 0:0(0) win 32792 <mss 1460,mp_join_syn flags: 0, address id: 0, receiver token: 143956527, sender random number: 590657082>
outbound sniffed packet:  0.027132 S. 1885174322:1885174322(0) ack 1 win 28800 <mss 1460,mp_join_syn_ack flags: 0, address id: 0, sender hmac: 8484337386671086230, sender random number: 845585034>
inbound injected packet:  0.127791 . 1:1(0) ack 1885174323 win 32792 <mp_join_ack sender hmac (160) bits, by 32bits bloc from [0] to [4]: 3127187271, 3807341752, 4065235748, 2785452501, 141418444>
outbound sniffed packet:  0.127937 . 1885174323:1885174323(0) ack 1 win 65535 <dss dack4 2070504321 flags: A>
outbound sniffed packet: 10.036222 . 3300006548:3300006548(0) ack 1001 win 65535 <dss dack4 2070504321 flags: A>
outbound sniffed packet: 10.132214 . 1885174322:1885174322(0) ack 1 win 65535 <dss dack4 2070504321 flags: A>
outbound sniffed packet: 11.036273 . 3300006548:3300006548(0) ack 1001 win 65535 <dss dack4 2070504321 flags: A>
outbound sniffed packet: 11.132249 . 1885174322:1885174322(0) ack 1 win 65535 <dss dack4 2070504321 flags: A>
outbound sniffed packet: 12.036301 . 3300006548:3300006548(0) ack 1001 win 65535 <dss dack4 2070504321 flags: A>
outbound sniffed packet: 12.132297 . 1885174322:1885174322(0) ack 1 win 65535 <dss dack4 2070504321 flags: A>
outbound sniffed packet: 13.036336 . 3300006548:3300006548(0) ack 1001 win 65535 <dss dack4 2070504321 flags: A>
outbound sniffed packet: 13.132342 . 1885174322:1885174322(0) ack 1 win 65535 <dss dack4 2070504321 flags: A>
outbound sniffed packet: 14.036394 . 3300006548:3300006548(0) ack 1001 win 65535 <dss dack4 2070504321 flags: A>
outbound sniffed packet: 14.132403 . 1885174322:1885174322(0) ack 1 win 65535 <dss dack4 2070504321 flags: A>
outbound sniffed packet: 15.036453 R. 3300006549:3300006549(0) ack 1001 win 65535 <dss dack4 2070504321 flags: A>

@redward redward closed this as completed Jul 7, 2014
matttbe pushed a commit to multipath-tcp/packetdrill_mptcp that referenced this issue Mar 1, 2022
@dcaratti
Merge pull request aschils#23 from matttbe/alg_bind_err
910aeb8 
Alg bind err
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@cpaasch @redward