[PATCH] Age Entry For IPv4 Route Table

[PATCH] Age Entry For IPv4 Route Table

[Varun Chandramohan]

According to the RFC 4292 (IP Forwarding Table MIB) there is a need for an age entry for all the routes in the routing table. The entry in the RFC is inetCidrRouteAge and oid is inetCidrRouteAge.1.10.
Many snmp application require this age entry. So iam adding the age field in the routing table and providing
the interface for this value via /proc/net/route.

Signed-off-by: Varun Chandramohan <varunc@linux.vnet.ibm.com>
---
 net/ipv4/fib_hash.c   |   16 +++++++++++-----
 net/ipv4/fib_lookup.h |    1 +
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/net/ipv4/fib_hash.c b/net/ipv4/fib_hash.c
index 07e843a..2000f1e 100644
--- a/net/ipv4/fib_hash.c
+++ b/net/ipv4/fib_hash.c
@@ -448,6 +448,7 @@ static int fn_hash_insert(struct fib_tab
 			fa->fa_info = fi;
 			fa->fa_type = cfg->fc_type;
 			fa->fa_scope = cfg->fc_scope;
+			fa->fa_age = jiffies;
 			state = fa->fa_state;
 			fa->fa_state &= ~FA_S_ACCESSED;
 			fib_hash_genid++;
@@ -507,6 +508,7 @@ static int fn_hash_insert(struct fib_tab
 	new_fa->fa_type = cfg->fc_type;
 	new_fa->fa_scope = cfg->fc_scope;
 	new_fa->fa_state = 0;
+	new_fa->fa_age = jiffies;
 
 	/*
 	 * Insert new entry to the list.
@@ -998,10 +1000,11 @@ static int fib_seq_show(struct seq_file
 	struct fib_alias *fa;
 	struct fib_info *fi;
 
+#define JIFFIES_TO_SECS(jiffies)   ((jiffies)/HZ)
 	if (v == SEQ_START_TOKEN) {
 		seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
 			   "\tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU"
-			   "\tWindow\tIRTT");
+			   "\tWindow\tIRTT\tAge");
 		goto out;
 	}
 
@@ -1014,17 +1017,20 @@ static int fib_seq_show(struct seq_file
 	flags	= fib_flag_trans(fa->fa_type, mask, fi);
 	if (fi)
 		snprintf(bf, sizeof(bf),
-			 "%s\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u",
+			 "%s\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u\t%lu",
 			 fi->fib_dev ? fi->fib_dev->name : "*", prefix,
 			 fi->fib_nh->nh_gw, flags, 0, 0, fi->fib_priority,
 			 mask, (fi->fib_advmss ? fi->fib_advmss + 40 : 0),
 			 fi->fib_window,
-			 fi->fib_rtt >> 3);
+			 fi->fib_rtt >> 3,
+			 JIFFIES_TO_SECS(jiffies - fa->fa_age));	
 	else
 		snprintf(bf, sizeof(bf),
-			 "*\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u",
-			 prefix, 0, flags, 0, 0, 0, mask, 0, 0, 0);
+			 "*\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u\t%lu",
+			 prefix, 0, flags, 0, 0, 0, mask, 0, 0, 0, 0);
 	seq_printf(seq, "%-127s\n", bf);
+
+#undef JIFFIES_TO_SECS
 out:
 	return 0;
 }
diff --git a/net/ipv4/fib_lookup.h b/net/ipv4/fib_lookup.h
index eef9eec..cc403d4 100644
--- a/net/ipv4/fib_lookup.h
+++ b/net/ipv4/fib_lookup.h
@@ -13,6 +13,7 @@ struct fib_alias {
 	u8			fa_type;
 	u8			fa_scope;
 	u8			fa_state;
+	unsigned long		fa_age;
 };
 
 #define FA_S_ACCESSED	0x01
-- 
1.4.3.4

Re: [PATCH] Age Entry For IPv4 Route Table

[YOSHIFUJI Hideaki / 吉藤英明]

In article <20070625102838.9d1fee20.varunc@linux.vnet.ibm.com> (at Mon, 25 Jun 2007 10:28:38 +0530), Varun Chandramohan <varunc@linux.vnet.ibm.com> says:

> According to the RFC 4292 (IP Forwarding Table MIB) there is a need for an age entry for all the routes in the routing table. The entry in the RFC is inetCidrRouteAge and oid is inetCidrRouteAge.1.10.
> Many snmp application require this age entry. So iam adding the age field in the routing table and providing
> the interface for this value via /proc/net/route.

I'm not in favor of adding new field(s) to /proc/net/route.

--yoshfuji

Re: [PATCH] Age Entry For IPv4 Route Table

[Varun Chandramohan]

YOSHIFUJI Hideaki / 吉藤英明 wrote:
> In article <20070625102838.9d1fee20.varunc@linux.vnet.ibm.com> (at Mon, 25 Jun 2007 10:28:38 +0530), Varun Chandramohan <varunc@linux.vnet.ibm.com> says:
>
>   
>> According to the RFC 4292 (IP Forwarding Table MIB) there is a need for an age entry for all the routes in the routing table. The entry in the RFC is inetCidrRouteAge and oid is inetCidrRouteAge.1.10.
>> Many snmp application require this age entry. So iam adding the age field in the routing table and providing
>> the interface for this value via /proc/net/route.
>>     
>
> I'm not in favor of adding new field(s) to /proc/net/route.
>
>   
Do you think it will break any user level functionality? I have tested
with netstat, route and net-snmp which reads from the same /proc
interface. They seem to work fine.
> --yoshfuji
> -
> To unsubscribe from this list: send the line "unsubscribe netdev" in
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>   

Re: [PATCH] Age Entry For IPv4 Route Table

[Varun Chandramohan]

David Miller wrote:
> From: Varun Chandramohan <varunc@linux.vnet.ibm.com>
> Date: Mon, 25 Jun 2007 10:51:39 +0530
>
>   
>> YOSHIFUJI Hideaki / ������������ wrote:
>>     
>>> In article <20070625102838.9d1fee20.varunc@linux.vnet.ibm.com> (at Mon, 25 Jun 2007 10:28:38 +0530), Varun Chandramohan <varunc@linux.vnet.ibm.com> says:
>>>
>>>   
>>>       
>>>> According to the RFC 4292 (IP Forwarding Table MIB) there is a need for an age entry for all the routes in the routing table. The entry in the RFC is inetCidrRouteAge and oid is inetCidrRouteAge.1.10.
>>>> Many snmp application require this age entry. So iam adding the age field in the routing table and providing
>>>> the interface for this value via /proc/net/route.
>>>>     
>>>>         
>>> I'm not in favor of adding new field(s) to /proc/net/route.
>>>
>>>   
>>>       
>> Do you think it will break any user level functionality? I have tested
>> with netstat, route and net-snmp which reads from the same /proc
>> interface. They seem to work fine.
>>     
>
> You can't change procfs file output format, someone's shell scripts
> or whatever out there will break.  Just testing some common packages
> isn't a way to be able to change procfs file output, it's a user
> exported API and just like system calls you cannot change them.
>
>   
Hi Dave,
    
        Ok i understand. But can you suggest anyother way to do the above?

Regards,
Varun

Re: [PATCH] Age Entry For IPv4 Route Table

[David Miller]

From: Varun Chandramohan <varunc@linux.vnet.ibm.com>
Date: Mon, 25 Jun 2007 13:28:37 +0530

> Ok i understand. But can you suggest anyother way to do the above?

Just because I found a fault in your patch doesn't mean that
it becomes my job isn't to implement the feature for you.

Re: [PATCH] Age Entry For IPv4 Route Table

[Eric Dumazet]

On Mon, 25 Jun 2007 10:28:38 +0530
Varun Chandramohan <varunc@linux.vnet.ibm.com> wrote:

> According to the RFC 4292 (IP Forwarding Table MIB) there is a need for an age entry for all the routes in the routing table. The entry in the RFC is inetCidrRouteAge and oid is inetCidrRouteAge.1.10.
> Many snmp application require this age entry. So iam adding the age field in the routing table and providing
> the interface for this value via /proc/net/route.
> 

Hi Varun

If you find a way to expose this information without breaking /proc/net/route, please consider that jiffies can wrap
every 49 days on 32 bit platforms.
So you probably want to use an other time infrastructure if you want meaningfull Age information.