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

From: Mitsuru Chinen <[email-masked]>
Date: Thu, 6 Dec 2007 17:14:21 +0900

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

> 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.

fib_lookup() replies -ESRCH in this situation.
It is necessary to override the variable by the suitable error
number like the code under e_hostunreach label.

Best Regards,
----
Mitsuru Chinen <[email-masked]>