Subject: Re: [PATCH] [IPv4] Reply net unreachable ICMP message

From: Jarek Poplawski <[email-masked]>
Date: Thu, 6 Dec 2007 08:49:47 +0100

On 06-12-2007 07:31, Mitsuru Chinen wrote:
> IPv4 stack doesn't reply any ICMP destination unreachable message
> with net unreachable code when IP detagrams are being discarded
> because of no route could be found in the forwarding path.
> Incidentally, IPv6 stack replies such ICMPv6 message in the similar
> situation.
> 
> Signed-off-by: Mitsuru Chinen <[email-masked]>
> ---
>  net/ipv4/route.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/net/ipv4/route.c b/net/ipv4/route.c
> index 6714bbc..ba85ec9 100644
> --- a/net/ipv4/route.c
> +++ b/net/ipv4/route.c
> @@ -1375,6 +1375,7 @@ static int ip_error(struct sk_buff *skb)
>  			break;
>  		case ENETUNREACH:
>  			code = ICMP_NET_UNREACH;
> +			IP_INC_STATS_BH(IPSTATS_MIB_INNOROUTES);
>  			break;
>  		case EACCES:
>  			code = ICMP_PKT_FILTERED;
> @@ -2004,6 +2005,7 @@ no_route:
>  	RT_CACHE_STAT_INC(in_no_route);
>  	spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
>  	res.type = RTN_UNREACHABLE;
> +	err = -ENETUNREACH;
>  	goto local_input;
>  
>  	/*

This patch seems to be wrong. It overrides err codes from
fib_lookup, where such decisions should be made.

Regards,
Jarek P.