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net: Fix behaviour of unreachable, blackhole and prohibit routes

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Man page of ip-route(8) says following about route types:

  unreachable - these destinations are unreachable.  Packets are dis‐
  carded and the ICMP message host unreachable is generated.  The local
  senders get an EHOSTUNREACH error.

  blackhole - these destinations are unreachable.  Packets are dis‐
  carded silently.  The local senders get an EINVAL error.

  prohibit - these destinations are unreachable.  Packets are discarded
  and the ICMP message communication administratively prohibited is
  generated.  The local senders get an EACCES error.

In the inet6 address family, this was correct, except the local senders
got ENETUNREACH error instead of EHOSTUNREACH in case of unreachable route.
In the inet address family, all three route types generated ICMP message
net unreachable, and the local senders got ENETUNREACH error.

In both address families all three route types now behave consistently
with documentation.

Signed-off-by: Nikola Forró <nforro@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Nikola Forró 2015-09-17 16:01:32 +02:00 committed by David S. Miller
parent ba5ca7848b
commit 0315e38270
3 changed files with 26 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
include/net/ip_fib.h
View File

@ -236,8 +236,11 @@ static inline int fib_lookup(struct net *net, const struct flowi4 *flp,
rcu_read_lock();
tb = fib_get_table(net, RT_TABLE_MAIN);
if (tb && !fib_table_lookup(tb, flp, res, flags | FIB_LOOKUP_NOREF))
err = 0;
if (tb)
err = fib_table_lookup(tb, flp, res, flags | FIB_LOOKUP_NOREF);
if (err == -EAGAIN)
err = -ENETUNREACH;
rcu_read_unlock();
@ -258,7 +261,7 @@ static inline int fib_lookup(struct net *net, struct flowi4 *flp,
struct fib_result *res, unsigned int flags)
{
struct fib_table *tb;
int err;
int err = -ENETUNREACH;
flags |= FIB_LOOKUP_NOREF;
if (net->ipv4.fib_has_custom_rules)
@ -268,15 +271,20 @@ static inline int fib_lookup(struct net *net, struct flowi4 *flp,
res->tclassid = 0;
for (err = 0; !err; err = -ENETUNREACH) {
tb = rcu_dereference_rtnl(net->ipv4.fib_main);
if (tb && !fib_table_lookup(tb, flp, res, flags))
break;
if (tb)
err = fib_table_lookup(tb, flp, res, flags);
if (!err)
goto out;
tb = rcu_dereference_rtnl(net->ipv4.fib_default);
if (tb && !fib_table_lookup(tb, flp, res, flags))
break;
}
if (tb)
err = fib_table_lookup(tb, flp, res, flags);
out:
if (err == -EAGAIN)
err = -ENETUNREACH;
rcu_read_unlock();

6
net/ipv4/route.c
View File

@ -2045,6 +2045,7 @@ struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *fl4)
struct fib_result res;
struct rtable *rth;
int orig_oif;
int err = -ENETUNREACH;
res.tclassid = 0;
res.fi = NULL;
@ -2153,7 +2154,8 @@ struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *fl4)
goto make_route;
}
if (fib_lookup(net, fl4, &res, 0)) {
err = fib_lookup(net, fl4, &res, 0);
if (err) {
res.fi = NULL;
res.table = NULL;
if (fl4->flowi4_oif) {
@ -2181,7 +2183,7 @@ struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *fl4)
res.type = RTN_UNICAST;
goto make_route;
}
rth = ERR_PTR(-ENETUNREACH);
rth = ERR_PTR(err);
goto out;
}

4
net/ipv6/route.c
View File

@ -1885,9 +1885,11 @@ int ip6_route_info_create(struct fib6_config *cfg, struct rt6_info **rt_ret)
rt->dst.input = ip6_pkt_prohibit;
break;
case RTN_THROW:
case RTN_UNREACHABLE:
default:
rt->dst.error = (cfg->fc_type == RTN_THROW) ? -EAGAIN
: -ENETUNREACH;
: (cfg->fc_type == RTN_UNREACHABLE)
? -EHOSTUNREACH : -ENETUNREACH;
rt->dst.output = ip6_pkt_discard_out;
rt->dst.input = ip6_pkt_discard;
break;