[Bug 222074] TCP stall with rfc1323 enabled
bugzilla-noreply at freebsd.org
bugzilla-noreply at freebsd.org
Tue Sep 5 16:44:11 UTC 2017
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=222074
Bug ID: 222074
Summary: TCP stall with rfc1323 enabled
Product: Base System
Version: 11.1-RELEASE
Hardware: Any
OS: Any
Status: New
Severity: Affects Only Me
Priority: ---
Component: kern
Assignee: freebsd-bugs at FreeBSD.org
Reporter: aragon at phat.za.net
I've stumbled upon some strange behaviour when RFC1323 is enabled in
conjunction with multiple layers of MPD interfaces. TCP transfers stall, and
with net.inet.tcp.log_debug enabled I see one kernel message get logged when
the stall occurs:
Sep 5 18:12:28 <kern.debug> roo kernel: TCP: [213.138.116.73]:80 to
[192.168.104.0]:48841 tcpflags 0x12<SYN,ACK>; tcp_do_segment: Timestamp not
expected, no action
My network setup looks like this:
192.168.104.0 [ng1] <-> MPD L2TP <-> 197.215.183.131 [ng0] <-> MPD PPPoE <->
Internet <-> 213.138.116.73
So in words, I'm running an L2TP tunnel over a PPPoE tunnel to my ISP, and all
these layers operate on the same host that's experiencing the RFC1323 related
TCP issue.
213.138.116.73 above is pkg.FreeBSD.org, and 192.168.104.0 is the local tunnel
address on the affected host. When I do an HTTP GET, eg.
curl -o /dev/null
http://pkg.FreeBSD.org/FreeBSD:11:amd64/quarterly/All/bird-1.6.3_3.txz
The transfer stalls after a few KB, and a tcpdump of ng1 shows this:
18:28:13.643389 IP 192.168.104.0.35277 > 213.138.116.73.80: Flags [S], seq
353584016, win 65535, options [mss 1360,nop,wscale 6,sackOK,TS val 764211736
ecr 0], length 0
18:28:13.835812 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [S.], seq
4183396526, ack 353584017, win 65535, options [mss 1310,nop,wscale 11,sackOK,TS
val 3582066608 ecr 764211736], length 0
18:28:13.835882 IP 192.168.104.0.35277 > 213.138.116.73.80: Flags [.], ack 1,
win 1043, options [nop,nop,TS val 764211928 ecr 3582066608], length 0
18:28:13.835970 IP 192.168.104.0.35277 > 213.138.116.73.80: Flags [P.], seq
1:127, ack 1, win 1043, options [nop,nop,TS val 764211928 ecr 3582066608],
length 126: HTTP: GET /FreeBSD:11:amd64/quarterly/All/bird-1.6.3_3.txz HTTP/1.1
18:28:14.028199 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], ack 127,
win 512, options [nop,nop,TS val 3582066800 ecr 764211928], length 0
18:28:14.028317 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
1:1299, ack 127, win 512, options [nop,nop,TS val 3582066800 ecr 764211928],
length 1298: HTTP: HTTP/1.1 200 OK
18:28:14.028482 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
1299:2597, ack 127, win 512, options [nop,nop,TS val 3582066800 ecr 764211928],
length 1298: HTTP
18:28:14.028498 IP 192.168.104.0.35277 > 213.138.116.73.80: Flags [.], ack
2597, win 1023, options [nop,nop,TS val 764212121 ecr 3582066800], length 0
18:28:14.028524 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
2597:3895, ack 127, win 512, options [nop,nop,TS val 3582066800 ecr 764211928],
length 1298: HTTP
18:28:14.028532 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
3895:5193, ack 127, win 512, options [nop,nop,TS val 3582066800 ecr 764211928],
length 1298: HTTP
18:28:14.028744 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
5193:6491, ack 127, win 512, options [nop,nop,TS val 3582066800 ecr 764211928],
length 1298: HTTP
18:28:14.028755 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
6491:7789, ack 127, win 512, options [nop,nop,TS val 3582066800 ecr 764211928],
length 1298: HTTP
18:28:14.028828 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
7789:9087, ack 127, win 512, options [nop,nop,TS val 3582066800 ecr 764211928],
length 1298: HTTP
18:28:14.028944 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
9087:10385, ack 127, win 512, options [nop,nop,TS val 3582066800 ecr
764211928], length 1298: HTTP
18:28:14.029071 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
10385:11683, ack 127, win 512, options [nop,nop,TS val 3582066800 ecr
764211928], length 1298: HTTP
18:28:14.220094 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
11683:12981, ack 127, win 512, options [nop,nop,TS val 3582066992 ecr
764212121], length 1298: HTTP
18:28:14.220112 IP 192.168.104.0.35277 > 213.138.116.73.80: Flags [.], ack
2597, win 1043, options [nop,nop,TS val 764212313 ecr 3582066800,nop,nop,sack 1
{11683:12981}], length 0
18:28:14.220136 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
12981:14279, ack 127, win 512, options [nop,nop,TS val 3582066992 ecr
764212121], length 1298: HTTP
18:28:14.220159 IP 192.168.104.0.35277 > 213.138.116.73.80: Flags [.], ack
2597, win 1043, options [nop,nop,TS val 764212313 ecr 3582066800,nop,nop,sack 1
{11683:14279}], length 0
18:28:14.412476 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
14279:15577, ack 127, win 512, options [nop,nop,TS val 3582067184 ecr
764212313], length 1298: HTTP
18:28:14.412489 IP 192.168.104.0.35277 > 213.138.116.73.80: Flags [.], ack
2597, win 1043, options [nop,nop,TS val 764212505 ecr 3582066800,nop,nop,sack 1
{11683:15577}], length 0
18:28:14.604109 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
2597:3895, ack 127, win 512, options [nop,nop,TS val 3582067376 ecr 764212505],
length 1298: HTTP
18:28:14.604127 IP 192.168.104.0.35277 > 213.138.116.73.80: Flags [.], ack
3895, win 1023, options [nop,nop,TS val 764212697 ecr 3582067376,nop,nop,sack 1
{11683:15577}], length 0
18:28:14.604236 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
3895:5193, ack 127, win 512, options [nop,nop,TS val 3582067376 ecr 764212505],
length 1298: HTTP
18:28:14.604257 IP 192.168.104.0.35277 > 213.138.116.73.80: Flags [.], ack
5193, win 1023, options [nop,nop,TS val 764212697 ecr 3582067376,nop,nop,sack 1
{11683:15577}], length 0
18:28:14.604287 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
5193:6491, ack 127, win 512, options [nop,nop,TS val 3582067376 ecr 764212505],
length 1298: HTTP
18:28:14.604298 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
6491:7789, ack 127, win 512, options [nop,nop,TS val 3582067376 ecr 764212505],
length 1298: HTTP
18:28:14.604357 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
7789:7837, ack 127, win 512, options [nop,nop,TS val 3582067376 ecr 764212505],
length 48: HTTP
18:28:14.604367 IP 192.168.104.0.35277 > 213.138.116.73.80: Flags [.], ack
5193, win 1043, options [nop,nop,TS val 764212697 ecr 3582067376,nop,nop,sack 2
{7789:7837}{11683:15577}], length 0
18:28:14.796498 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
7837:9135, ack 127, win 512, options [nop,nop,TS val 3582067568 ecr 764212697],
length 1298: HTTP
18:28:14.796513 IP 192.168.104.0.35277 > 213.138.116.73.80: Flags [.], ack
5193, win 1043, options [nop,nop,TS val 764212889 ecr 3582067376,nop,nop,sack 2
{7789:9135}{11683:15577}], length 0
18:28:14.796533 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
9135:10433, ack 127, win 512, options [nop,nop,TS val 3582067568 ecr
764212697], length 1298: HTTP
18:28:14.796544 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
10433:10481, ack 127, win 512, options [nop,nop,TS val 3582067568 ecr
764212697], length 48: HTTP
18:28:14.988262 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
10481:11683, ack 127, win 512, options [nop,nop,TS val 3582067760 ecr
764212889], length 1202: HTTP
18:28:14.988275 IP 192.168.104.0.35277 > 213.138.116.73.80: Flags [.], ack
5193, win 1043, options [nop,nop,TS val 764213081 ecr 3582067376,nop,nop,sack 2
{10481:15577}{7789:9135}], length 0
18:28:15.204013 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
5193:6491, ack 127, win 512, options [nop,nop,TS val 3582067976 ecr 764213081],
length 1298: HTTP
18:28:15.204030 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
6491:6503, ack 127, win 512, options [nop,nop,TS val 3582067976 ecr 764213081],
length 12: HTTP
18:28:15.820052 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
5193:6491, ack 127, win 512, options [nop,nop,TS val 3582068592 ecr 764213081],
length 1298: HTTP
18:28:15.820066 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
6491:6503, ack 127, win 512, options [nop,nop,TS val 3582068592 ecr 764213081],
length 12: HTTP
18:28:16.852097 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
5193:6491, ack 127, win 512, options [nop,nop,TS val 3582069624 ecr 764213081],
length 1298: HTTP
18:28:16.852110 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
6491:6503, ack 127, win 512, options [nop,nop,TS val 3582069624 ecr 764213081],
length 12: HTTP
18:28:18.716112 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
5193:6491, ack 127, win 512, options [nop,nop,TS val 3582071488 ecr 764213081],
length 1298: HTTP
18:28:18.716125 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
6491:6503, ack 127, win 512, options [nop,nop,TS val 3582071488 ecr 764213081],
length 12: HTTP
18:28:22.243953 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
5193:6491, ack 127, win 512, options [nop,nop,TS val 3582075016 ecr 764213081],
length 1298: HTTP
18:28:22.243965 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
6491:6503, ack 127, win 512, options [nop,nop,TS val 3582075016 ecr 764213081],
length 12: HTTP
18:28:29.099858 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
5193:6491, ack 127, win 512, options [nop,nop,TS val 3582081872 ecr 764213081],
length 1298: HTTP
18:28:29.099872 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
6491:6503, ack 127, win 512, options [nop,nop,TS val 3582081872 ecr 764213081],
length 12: HTTP
18:28:42.614902 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
5193:6491, ack 127, win 512, options [nop,nop,TS val 3582095387 ecr 764213081],
length 1298: HTTP
18:28:42.614915 IP 213.138.116.73.80 > 192.168.104.0.35277: Flags [.], seq
6491:6503, ack 127, win 512, options [nop,nop,TS val 3582095387 ecr 764213081],
length 12: HTTP
If I disable net.inet.tcp.rfc1323, the transfer succeeds with no kernel
messages.
If I enable net.inet.tcp.rfc1323, but I route IP traffic via the PPPoE
interface (one less NG/MPD layer), the transfer succeeds with 1 kernel message:
Sep 5 18:39:45 <kern.debug> roo kernel: TCP: [213.138.116.73]:80 to
[197.215.183.131]:59766 tcpflags 0x12<SYN,ACK>; tcp_do_segment: Timestamp not
expected, no action
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