Re: ip_no_pmtu_disc and UDP

2015-10-26 Thread Hannes Frederic Sowa
On Mon, Oct 26, 2015, at 23:53, Vincent Li wrote: > ok, I observed if i increase the UDP client packet size > local > interface MTU 1500, the client will fragment the packet first and > then send it out, if the UDP client packet size < local interface MTU > 1500, the DF bit will be set when ip_no

Re: ip_no_pmtu_disc and UDP

2015-10-26 Thread Vincent Li
ok, I observed if i increase the UDP client packet size > local interface MTU 1500, the client will fragment the packet first and then send it out, if the UDP client packet size < local interface MTU 1500, the DF bit will be set when ip_no_pmtu_disc set to 0, is this expected behavior ? On Mon

Re: ip_no_pmtu_disc and UDP

2015-10-26 Thread Vincent Li
I test again and i did see DF bit now, it is weird. I am going to do more test, sorry for the noise. On Mon, Oct 26, 2015 at 3:12 PM, Hannes Frederic Sowa wrote: > Hello, > > On Mon, Oct 26, 2015, at 23:00, Vincent Li wrote: >> the UDP packet size is about 768, here is how packet path like: >> >

Re: ip_no_pmtu_disc and UDP

2015-10-26 Thread Hannes Frederic Sowa
Hello, On Mon, Oct 26, 2015, at 23:00, Vincent Li wrote: > the UDP packet size is about 768, here is how packet path like: > > client > server > (eth0 mtu 1500 ip 10.3.72.69) (eth0 mtu 1500 ip

Re: ip_no_pmtu_disc and UDP

2015-10-26 Thread Vincent Li
the UDP packet size is about 768, here is how packet path like: client server (eth0 mtu 1500 ip 10.3.72.69) (eth0 mtu 1500 ip 10.3.72.1, (eth0 mtu 1500 ip 10.2.72.99)

Re: ip_no_pmtu_disc and UDP

2015-10-23 Thread David Miller
From: Vincent Li Date: Fri, 23 Oct 2015 10:01:50 -0700 > I think the no_pmtu_disc could be renamed to pmtu_disc to be less > confusion to users. We cannot rename sysctl values exported to the user without breaking things. -- To unsubscribe from this list: send the line "unsubscribe netdev" in t

Re: ip_no_pmtu_disc and UDP

2015-10-23 Thread Hannes Frederic Sowa
Hello, On Fri, Oct 23, 2015, at 18:45, Vincent Li wrote: > It looks ip_no_pmtu_disc setting does not affect UDP IP packet DF bit > setting, is that intended behavior? echo 0, 1, 2, 3 respectively to > ip_no_pmtu_disc, UDP IP packet always have DF bit cleared, unless use > IP_PMTUDISC_DO on IP_MTU_

Re: ip_no_pmtu_disc and UDP

2015-10-23 Thread Vincent Li
I think the no_pmtu_disc could be renamed to pmtu_disc to be less confusion to users. pmtu_disc: IP_PMTUDISC_DONT, clear DF bit pmtu_disc: IP_PMTUDISC_WANT, set DF bit just my .2 cents On Fri, Oct 23, 2015 at 9:45 AM, Vincent Li wrote: > Hi, > > It looks ip_no_pmtu_disc setting does not affec

ip_no_pmtu_disc and UDP

2015-10-23 Thread Vincent Li
Hi, It looks ip_no_pmtu_disc setting does not affect UDP IP packet DF bit setting, is that intended behavior? echo 0, 1, 2, 3 respectively to ip_no_pmtu_disc, UDP IP packet always have DF bit cleared, unless use IP_PMTUDISC_DO on IP_MTU_DISCOVER as ip man page says. in inet_create, seems to prove