CONFIG_ARPD help text

CONFIG_ARPD help text

[Timo Teräs]

Hi,

I just re-read again the CONFIG_ARPD help text. It says it's
"experimental and also obsolete".

But as opennhrp relies on this, and has shown the usefulness for
this interface - it can be used to implement other protocols that
resolve neighbor address than ARP in userland. In this case the
NHRP protocol.

Would it be acceptable to remove the designation as "obsolete"?

Also, I'm running the opennhrp on production with reasonable
size network (100+ nodes in gre subnet). And with the fix I sent
previously it seems to work very stable. Is there something more
to be done, or could the "experimental" marking be removed also?

I could also update the help to explain where the option is useful.
Or should the option be renamed to something like NEIGH_NETLINK?
It also seems that IPv6 supports CONFIG_ARPD so it should probably
be moved from net/ipv4/Kconfig to likely net/core/Kconfig?

Thanks,
  Timo

Re: CONFIG_ARPD help text

[David Miller]

From: Timo Teräs <timo.teras@iki.fi>
Date: Thu, 11 Jun 2009 21:28:21 +0300

> I just re-read again the CONFIG_ARPD help text. It says it's
> "experimental and also obsolete".
> 
> But as opennhrp relies on this, and has shown the usefulness for
> this interface - it can be used to implement other protocols that
> resolve neighbor address than ARP in userland. In this case the
> NHRP protocol.
> 
> Would it be acceptable to remove the designation as "obsolete"?
> 
> Also, I'm running the opennhrp on production with reasonable
> size network (100+ nodes in gre subnet). And with the fix I sent
> previously it seems to work very stable. Is there something more
> to be done, or could the "experimental" marking be removed also?
> 
> I could also update the help to explain where the option is useful.
> Or should the option be renamed to something like NEIGH_NETLINK?
> It also seems that IPv6 supports CONFIG_ARPD so it should probably
> be moved from net/ipv4/Kconfig to likely net/core/Kconfig?

I think it's rediculious to have these tags on something that's
been in active, useful, use for years.  Feel free to remove them
and to expand the help text.

Thanks!

[PATCH] ipv4: update ARPD help text

[Timo Teras]

Removed the statements about ARP cache size as this config option does
not affect it. The cache size is controlled by neigh_table gc thresholds.

Remove also expiremental and obsolete markings as the API originally
intended for arp caching is useful for implementing ARP-like protocols
(e.g. NHRP) in user space and has been there for a long enough time.

Signed-off-by: Timo Teras <timo.teras@iki.fi>
---
 net/ipv4/Kconfig |   35 +++++++++++++----------------------
 1 files changed, 13 insertions(+), 22 deletions(-)

diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index 5b919f7..70491d9 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -273,29 +273,20 @@ config IP_PIMSM_V2
 	  you want to play with it.
 
 config ARPD
-	bool "IP: ARP daemon support (EXPERIMENTAL)"
-	depends on EXPERIMENTAL
+	bool "IP: ARP daemon support"
 	---help---
-	  Normally, the kernel maintains an internal cache which maps IP
-	  addresses to hardware addresses on the local network, so that
-	  Ethernet/Token Ring/ etc. frames are sent to the proper address on
-	  the physical networking layer. For small networks having a few
-	  hundred directly connected hosts or less, keeping this address
-	  resolution (ARP) cache inside the kernel works well. However,
-	  maintaining an internal ARP cache does not work well for very large
-	  switched networks, and will use a lot of kernel memory if TCP/IP
-	  connections are made to many machines on the network.
-
-	  If you say Y here, the kernel's internal ARP cache will never grow
-	  to more than 256 entries (the oldest entries are expired in a LIFO
-	  manner) and communication will be attempted with the user space ARP
-	  daemon arpd. Arpd then answers the address resolution request either
-	  from its own cache or by asking the net.
-
-	  This code is experimental and also obsolete. If you want to use it,
-	  you need to find a version of the daemon arpd on the net somewhere,
-	  and you should also say Y to "Kernel/User network link driver",
-	  below. If unsure, say N.
+	  The kernel maintains an internal cache which maps IP addresses to
+	  hardware addresses on the local network, so that Ethernet/Token Ring/
+	  etc. frames are sent to the proper address on the physical networking
+	  layer. Normally, kernel uses the ARP protocol to resolve these
+	  mappings.
+
+	  Saying Y here adds support to have an user space daemon to do this
+	  resolution instead. This is useful for implementing an alternate
+	  address resolution protocol (e.g. NHRP on mGRE tunnels) and also for
+	  testing purposes.
+
+	  If unsure, say N.
 
 config SYN_COOKIES
 	bool "IP: TCP syncookie support (disabled per default)"
-- 
1.6.0.4

Re: [PATCH] ipv4: update ARPD help text

[David Miller]

From: Timo Teras <timo.teras@iki.fi>
Date: Fri, 12 Jun 2009 08:38:02 +0300

> Removed the statements about ARP cache size as this config option does
> not affect it. The cache size is controlled by neigh_table gc thresholds.
> 
> Remove also expiremental and obsolete markings as the API originally
> intended for arp caching is useful for implementing ARP-like protocols
> (e.g. NHRP) in user space and has been there for a long enough time.
> 
> Signed-off-by: Timo Teras <timo.teras@iki.fi>

Applied.