+ycheng On Fri, Jan 4, 2013 at 1:11 PM, Dave Taht wrote: > Hmm. I would lean towards there being an issue with the new (freshly > ported forward to 3.7.1) unaligned checksum code for mips based on > what you say here. Or an offload... > > As for the 239.x multicast issue, hmm... separate issue entirely. > Probably... > > And then there's TFO. I note that in order to use it properly you need > to turn it on in proc. Last I remember that was > > echo 3 > /proc/sys/net/ipv4/tcp_fastopen > Correct - to enable the normal use of TFO for both client and server. There are other flags for advanced usage: /* Bit Flags for sysctl_tcp_fastopen */ #define TFO_CLIENT_ENABLE 1 #define TFO_SERVER_ENABLE 2 #define TFO_CLIENT_NO_COOKIE 4 /* Send data-in-SYN w/o cookie */ /* Process SYN data but skip cookie validation */ #define TFO_SERVER_COOKIE_NOT_CHKED 0x100 /* Accept SYN data w/o any cookie option */ #define TFO_SERVER_COOKIE_NOT_REQD 0x200 /* Force enable TFO on all listeners, i.e., not requiring the * TCP_FASTOPEN socket option. SOCKOPT1/2 determine how to set max_qlen. */ #define TFO_SERVER_WO_SOCKOPT1 0x400 #define TFO_SERVER_WO_SOCKOPT2 0x800 /* Always create TFO child sockets on a TFO listener even when * cookie/data not present. (For testing purpose!) */ #define TFO_SERVER_ALWAYS 0x1000 > However that's an old memory and there is this tcp_fastopen_key file I > don't know anything about yet (this is such bleeding edge stuff!) > > ... and with tcp_fastopen disabled things should still work right... > so I'm thinking something else is busted in the stack. > > I've also observed a dns slowdown in what I've been testing but hadn't > dug into packet dumps. (and was assuming, until now, it was due to me > fiddling with ULAs inside the network) Thanks for digging this deep! > > I never said this first attempt at 3.7 for cero was going to be > perfect, but we've entered a new age of subtle problems here. > > I strongly suggest nobody else try this dev build as a default gw, and > that the TFO folk ignore the noise for now. > SG. Jerry > > I just got a 3.7.1 box built on x86_64 so as to a/b some captures. > Regrettably I'm short on time through the weekend... > > On Fri, Jan 4, 2013 at 12:42 PM, Maciej Soltysiak > wrote: > > I am seeing something strange here, with polipo related to TFO but also > DNS. > > When I just took 3.7.1-1 and set my windows 7 laptop to use > gw.home.lan:8123 > > as http proxy it didn't work. What I observed was: > > A) after quite a while polipo's response to browser was 504 Host > > www.osnews.com lookup failed: Timeout > > b) this error in ssh console: Host osnews.com lookup failed: Timeout > > (131072) > > c) Disabling TFO by adding option useTCPFastOpen 'false' to config > 'polipo' > > 'general' works around the problem > > d) Alternatively, you can keep TFO enabled in polipo but change option > > 'dnsUseGethostbyname' from 'reluctantly' to 'true' (!) > > This is very weird, because TFO is TCP and the DNS queries fired off by > > polipo are UDP: > > root@OpenWrt:/tmp/log# tcpdump -n -v -vv -vvv -x -X -s 1500 -i lo > > 20:21:56.160245 IP (tos 0x0, ttl 64, id 50129, offset 0, flags [DF], > proto > > UDP (17), length 60) > > 127.0.0.1.47304 > 127.0.0.1.53: [bad udp cksum 0xfe3b -> 0xd17f!] 55396+ > A? > > www.osnews.com. (32) > > 0x0000: 4500 003c c3d1 4000 4011 78dd 7f00 0001 E..<..@.@.x..... > > 0x0010: 7f00 0001 b8c8 0035 0028 fe3b d864 0100 .......5.(.;.d.. > > 0x0020: 0001 0000 0000 0000 0377 7777 066f 736e .........www.osn > > 0x0030: 6577 7303 636f 6d00 0001 0001 ews.com..... > > 20:21:56.160319 IP (tos 0x0, ttl 64, id 50130, offset 0, flags [DF], > proto > > UDP (17), length 60) > > 127.0.0.1.47304 > 127.0.0.1.53: [bad udp cksum 0xfe3b -> 0xd164!] 55396+ > > AAAA? www.osnews.com. (32) > > 0x0000: 4500 003c c3d2 4000 4011 78dc 7f00 0001 E..<..@.@.x..... > > 0x0010: 7f00 0001 b8c8 0035 0028 fe3b d864 0100 .......5.(.;.d.. > > 0x0020: 0001 0000 0000 0000 0377 7777 066f 736e .........www.osn > > 0x0030: 6577 7303 636f 6d00 001c 0001 ews.com..... > > 20:21:56.169942 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto > UDP > > (17), length 123) > > 127.0.0.1.53 > 127.0.0.1.47304: [bad udp cksum 0xfe7a -> 0x5f73!] 55396 > q: > > A? www.osnews.com. 1/2/0 www.osnews.com. [29m3s] A 74.86.31.159 ns: > > osnews.com. [29m3s] NS ns2.swelter.net., osnews.com. [29m3s] NS > > ns1.swelter.net. (95) > > 0x0000: 4500 007b 0000 4000 4011 3c70 7f00 0001 E..{..@.@. > 0x0010: 7f00 0001 0035 b8c8 0067 fe7a d864 8180 .....5...g.z.d.. > > 0x0020: 0001 0001 0002 0000 0377 7777 066f 736e .........www.osn > > 0x0030: 6577 7303 636f 6d00 0001 0001 c00c 0001 ews.com......... > > 0x0040: 0001 0000 06cf 0004 4a56 1f9f c010 0002 ........JV...... > > 0x0050: 0001 0000 06cf 0011 036e 7332 0773 7765 .........ns2.swe > > 0x0060: 6c74 6572 036e 6574 00c0 1000 0200 0100 lter.net........ > > 0x0070: 0006 cf00 0603 6e73 31c0 40 ......ns1.@ > > 20:21:56.173901 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto > UDP > > (17), length 135) > > 127.0.0.1.53 > 127.0.0.1.47304: [bad udp cksum 0xfe86 -> 0x8ecb!] 55396 > q: > > AAAA? www.osnews.com. 1/2/0 www.osnews.com. [54m44s] AAAA > > 2607:f0d0:1002:62::3 ns: osnews.com. [29m3s] NS ns1.swelter.net., > > osnews.com. [29m3s] NS ns2.swelter.net. (107) > > 0x0000: 4500 0087 0000 4000 4011 3c64 7f00 0001 E.....@.@. > 0x0010: 7f00 0001 0035 b8c8 0073 fe86 d864 8180 .....5...s...d.. > > 0x0020: 0001 0001 0002 0000 0377 7777 066f 736e .........www.osn > > 0x0030: 6577 7303 636f 6d00 001c 0001 c00c 001c ews.com......... > > 0x0040: 0001 0000 0cd4 0010 2607 f0d0 1002 0062 ........&......b > > 0x0050: 0000 0000 0000 0003 c010 0002 0001 0000 ................ > > 0x0060: 06cf 0011 036e 7331 0773 7765 6c74 6572 .....ns1.swelter > > 0x0070: 036e 6574 00c0 1000 0200 0100 0006 cf00 .net............ > > 0x0080: 0603 6e73 32c0 4c ..ns2.L > > This is the only DNS traffic I saw during the attempts. The tcpdumps have > > udp bad checksum but when I disabled TFO in polipo, the UDP where still > bad > > checksum but they worked. > > Really weird. > > p.s. UPNP still works for port forwarding negotiation as it did in > 3.6.11-4 > > I still couldn't get the UPNP/SSDP broadcasts (udp to 239.255.255.250) to > > being forwarded between se00 and sw00/sw10. Last time it worked was > ~3.3.8. > > I'm starting not to question why it doesn't work, I'm starting to wonder > why > > it did work then ;-) > > Regards, > > Maciej > > On Fri, Jan 4, 2013 at 6:33 PM, Dave Taht wrote: > >> > >> On Fri, Jan 4, 2013 at 9:27 AM, Eric Dumazet > wrote: > >> > Sorry, could you give us a copy of the panic stack trace ? > >> > >> I will get a serial console up on a wndr3800 by sunday. (sorry, just > >> landed in california, am in disarray) > >> > >> The latest dev build of cero for the wndr3800 and wndr3700v2 is at: > >> > >> http://snapon.lab.bufferbloat.net/~cero2/cerowrt/wndr/3.7.1-1/ > >> > >> -- > >> Dave Täht > >> > >> Fixing bufferbloat with cerowrt: > >> http://www.teklibre.com/cerowrt/subscribe.html > >> _______________________________________________ > >> Cerowrt-devel mailing list > >> Cerowrt-devel@lists.bufferbloat.net > >> https://lists.bufferbloat.net/listinfo/cerowrt-devel > > > > > > > > -- > Dave Täht > > Fixing bufferbloat with cerowrt: > http://www.teklibre.com/cerowrt/subscribe.html >