On Tue, 26 Feb 2008 18:59:08 +0900
Wei Yongjun <[EMAIL PROTECTED]> wrote:
> Jarek Poplawski wrote:
>
> Maybe ip_error() does not handle the ESRCH error. In this place ESRCH eq
> to ENETUNREACH?
>
> static int ip_error(struct sk_buff *skb)
> {
> struct rtable *rt = (struct rtable*)skb->dst;
> unsigned long now;
> int code;
>
> switch (rt->u.dst.error) {
> case EINVAL:
> default:
> goto out;
> case EHOSTUNREACH:
> code = ICMP_HOST_UNREACH;
> break;
> case ENETUNREACH:
> code = ICMP_NET_UNREACH;
> break;
> case EACCES:
> code = ICMP_PKT_FILTERED;
> break;
> }
> ...............snip....................
> }
>
>
>
> > On 26-02-2008 07:34, Li Yewang wrote:
> >
> >> Hi All
> >>
> >> There is a bug about icmp netunreach.
> >> If the kernel does not find a route for a packet,
> >> it must send a icmp netunreach packet to the source host,
> >> and discard the packet. But the kernel does not send
> >> a icmp netunreach packet because of the fib_lookup
> >> return value of -ESRCH when a route is not found.
> >>
> >
> > ...or because some function doesn't handle -ESRCH return from
> > fib_lookup? It seems changing this to -ESRCH was needed in some cases.
> > And you don't explain enough why it can't be handled later (like in
> > ipv4/route.c: ip_route_input_slow)?
> >
>
>
> > Regards,
> > Jarek P.
> >
> >
> >> Signed-off-by: Li Yewang <[EMAIL PROTECTED]>
> >>
> >> diff -Nurp net/core_back/fib_rules.c net/core/fib_rules.c
> >> --- net/core_back/fib_rules.c 2008-02-25 13:15:37.000000000 +0800
> >> +++ net/core/fib_rules.c 2008-02-25 13:16:01.000000000 +0800
> >> @@ -188,7 +188,7 @@ jumped:
> >> }
> >> }
> >>
> >> - err = -ESRCH;
> >> + err = -ENETUNREACH;
> >> out:
> >> rcu_read_unlock();
> >>
> >>
The switch shouldn't see a problem because ENETUNREACH is already substituted
for ESRCH in:
static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
u8 tos, struct net_device *dev)
{
...
/*
* Now we are ready to route packet.
*/
if ((err = fib_lookup(net, &fl, &res)) != 0) {
if (!IN_DEV_FORWARD(in_dev))
goto e_hostunreach;
goto no_route;
...
no_route:
RT_CACHE_STAT_INC(in_no_route);
spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
res.type = RTN_UNREACHABLE;
if (err == -ESRCH)
err = -ENETUNREACH;
goto local_input;
--
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