* [PATCH linux-next] Documentation: fix outdated interpretation of ip_no_pmtu_disc
@ 2021-12-29 3:12 cgel.zte
2021-12-29 20:15 ` Jakub Kicinski
0 siblings, 1 reply; 4+ messages in thread
From: cgel.zte @ 2021-12-29 3:12 UTC (permalink / raw)
To: davem; +Cc: kuba, corbet, netdev, linux-doc, linux-kernel, xu xin, Zeal Robot
From: xu xin <xu.xin16@zte.com.cn>
The updating way of pmtu has changed, but documentation is still in the
old way. See commit-id 28d35bcdd3925e7293408cdb8aa5f2aac5f0d6e3. So This
patch fix interpretation of ip_no_pmtu_disc.
Besides, min_pmtu seems not to be discoverd, but set.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
---
Documentation/networking/ip-sysctl.rst | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index c04431144f7a..dd5e53318805 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -25,9 +25,11 @@ ip_default_ttl - INTEGER
ip_no_pmtu_disc - INTEGER
Disable Path MTU Discovery. If enabled in mode 1 and a
fragmentation-required ICMP is received, the PMTU to this
- destination will be set to min_pmtu (see below). You will need
- to raise min_pmtu to the smallest interface MTU on your system
- manually if you want to avoid locally generated fragments.
+ destination will be set to the smallest of the old MTU
+ and ip_rt_min_pmtu (see __ip_rt_update_pmtu() in
+ net/ipv4/route.c). You will need to raise min_pmtu to the
+ smallest interface MTU on your system manually if you want to
+ avoid locally generated fragments.
In mode 2 incoming Path MTU Discovery messages will be
discarded. Outgoing frames are handled the same as in mode 1,
@@ -49,7 +51,7 @@ ip_no_pmtu_disc - INTEGER
Default: FALSE
min_pmtu - INTEGER
- default 552 - minimum discovered Path MTU
+ default 552 - minimum set Path MTU
ip_forward_use_pmtu - BOOLEAN
By default we don't trust protocol path MTUs while forwarding
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH linux-next] Documentation: fix outdated interpretation of ip_no_pmtu_disc
2021-12-29 3:12 [PATCH linux-next] Documentation: fix outdated interpretation of ip_no_pmtu_disc cgel.zte
@ 2021-12-29 20:15 ` Jakub Kicinski
2021-12-30 3:28 ` [PATCH v2] " cgel.zte
0 siblings, 1 reply; 4+ messages in thread
From: Jakub Kicinski @ 2021-12-29 20:15 UTC (permalink / raw)
To: cgel.zte
Cc: davem, corbet, netdev, linux-doc, linux-kernel, xu xin, Zeal Robot
On Wed, 29 Dec 2021 03:12:45 +0000 cgel.zte@gmail.com wrote:
> From: xu xin <xu.xin16@zte.com.cn>
>
> The updating way of pmtu has changed, but documentation is still in the
> old way. See commit-id 28d35bcdd3925e7293408cdb8aa5f2aac5f0d6e3. So This
not a correct way to quote a commit, please use: %h (\"%s\")
as the format.
> patch fix interpretation of ip_no_pmtu_disc.
>
> Besides, min_pmtu seems not to be discoverd, but set.
>
> Reported-by: Zeal Robot <zealci@zte.com.cn>
How does the bot discover this sort of problem?
> Signed-off-by: xu xin <xu.xin16@zte.com.cn>
> ---
> Documentation/networking/ip-sysctl.rst | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
> index c04431144f7a..dd5e53318805 100644
> --- a/Documentation/networking/ip-sysctl.rst
> +++ b/Documentation/networking/ip-sysctl.rst
> @@ -25,9 +25,11 @@ ip_default_ttl - INTEGER
> ip_no_pmtu_disc - INTEGER
> Disable Path MTU Discovery. If enabled in mode 1 and a
> fragmentation-required ICMP is received, the PMTU to this
> - destination will be set to min_pmtu (see below). You will need
> - to raise min_pmtu to the smallest interface MTU on your system
> - manually if you want to avoid locally generated fragments.
> + destination will be set to the smallest of the old MTU
> + and ip_rt_min_pmtu (see __ip_rt_update_pmtu() in
I don't see how this is a meaningful distinction to someone reading
this documentation, more of a corner case.
> + net/ipv4/route.c). You will need to raise min_pmtu to the
> + smallest interface MTU on your system manually if you want to
> + avoid locally generated fragments.
Use tabs instead of spaces.
> In mode 2 incoming Path MTU Discovery messages will be
> discarded. Outgoing frames are handled the same as in mode 1,
> @@ -49,7 +51,7 @@ ip_no_pmtu_disc - INTEGER
> Default: FALSE
>
> min_pmtu - INTEGER
> - default 552 - minimum discovered Path MTU
> + default 552 - minimum set Path MTU
Also not must of an improvement IMHO.
> ip_forward_use_pmtu - BOOLEAN
> By default we don't trust protocol path MTUs while forwarding
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v2] Documentation: fix outdated interpretation of ip_no_pmtu_disc
2021-12-29 20:15 ` Jakub Kicinski
@ 2021-12-30 3:28 ` cgel.zte
2021-12-30 13:30 ` patchwork-bot+netdevbpf
0 siblings, 1 reply; 4+ messages in thread
From: cgel.zte @ 2021-12-30 3:28 UTC (permalink / raw)
To: kuba, davem, corbet; +Cc: netdev, linux-kernel, linux-doc, xu xin, Zeal Robot
From: xu xin <xu.xin16@zte.com.cn>
The updating way of pmtu has changed, but documentation is still in the
old way. So this patch updates the interpretation of ip_no_pmtu_disc and
min_pmtu.
See commit 28d35bcdd3925 ("net: ipv4: don't let PMTU updates increase
route MTU")
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
---
Documentation/networking/ip-sysctl.rst | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index c04431144f7a..2572eecc3e86 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -25,7 +25,8 @@ ip_default_ttl - INTEGER
ip_no_pmtu_disc - INTEGER
Disable Path MTU Discovery. If enabled in mode 1 and a
fragmentation-required ICMP is received, the PMTU to this
- destination will be set to min_pmtu (see below). You will need
+ destination will be set to the smallest of the old MTU to
+ this destination and min_pmtu (see below). You will need
to raise min_pmtu to the smallest interface MTU on your system
manually if you want to avoid locally generated fragments.
@@ -49,7 +50,8 @@ ip_no_pmtu_disc - INTEGER
Default: FALSE
min_pmtu - INTEGER
- default 552 - minimum discovered Path MTU
+ default 552 - minimum Path MTU. Unless this is changed mannually,
+ each cached pmtu will never be lower than this setting.
ip_forward_use_pmtu - BOOLEAN
By default we don't trust protocol path MTUs while forwarding
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] Documentation: fix outdated interpretation of ip_no_pmtu_disc
2021-12-30 3:28 ` [PATCH v2] " cgel.zte
@ 2021-12-30 13:30 ` patchwork-bot+netdevbpf
0 siblings, 0 replies; 4+ messages in thread
From: patchwork-bot+netdevbpf @ 2021-12-30 13:30 UTC (permalink / raw)
To: CGEL
Cc: kuba, davem, corbet, netdev, linux-kernel, linux-doc, xu.xin16, zealci
Hello:
This patch was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:
On Thu, 30 Dec 2021 03:28:56 +0000 you wrote:
> From: xu xin <xu.xin16@zte.com.cn>
>
> The updating way of pmtu has changed, but documentation is still in the
> old way. So this patch updates the interpretation of ip_no_pmtu_disc and
> min_pmtu.
>
> See commit 28d35bcdd3925 ("net: ipv4: don't let PMTU updates increase
> route MTU")
>
> [...]
Here is the summary with links:
- [v2] Documentation: fix outdated interpretation of ip_no_pmtu_disc
https://git.kernel.org/netdev/net/c/be1c5b53227b
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-12-29 3:12 [PATCH linux-next] Documentation: fix outdated interpretation of ip_no_pmtu_disc cgel.zte
2021-12-29 20:15 ` Jakub Kicinski
2021-12-30 3:28 ` [PATCH v2] " cgel.zte
2021-12-30 13:30 ` patchwork-bot+netdevbpf
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