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ipv4: fib: Fix metrics match when deleting a route 

The recently added fib_metrics_match() causes a regression for routes
with both RTAX_FEATURES and RTAX_CC_ALGO if the latter has
TCP_CONG_NEEDS_ECN flag set:

| # ip link add d0 type dummy
| # ip link set d0 up
| # ip route add 172.29.29.0/24 dev d0 features ecn congctl dctcp
| # ip route del 172.29.29.0/24 dev d0 features ecn congctl dctcp
| RTNETLINK answers: No such process

During route insertion, fib_convert_metrics() detects that the given CC
algo requires ECN and hence sets DST_FEATURE_ECN_CA bit in
RTAX_FEATURES.

During route deletion though, fib_metrics_match() compares stored
RTAX_FEATURES value with that from userspace (which obviously has no
knowledge about DST_FEATURE_ECN_CA) and fails.

Fixes: 5f9ae3d9e7 ("ipv4: do metrics match when looking up and deleting a route")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Phil Sutter 2017-12-19 15:17:13 +01:00 committed by David S. Miller
parent a176245699
commit d03a45572e
1 changed files with 6 additions and 2 deletions
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8
net/ipv4/fib_semantics.c
View File

@ -698,7 +698,7 @@ bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
int type = nla_type(nla);
u32 val;
u32 fi_val, val;
if (!type)
continue;
@ -715,7 +715,11 @@ bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
val = nla_get_u32(nla);
}
if (fi->fib_metrics->metrics[type - 1] != val)
fi_val = fi->fib_metrics->metrics[type - 1];
if (type == RTAX_FEATURES)
fi_val &= ~DST_FEATURE_ECN_CA;
if (fi_val != val)
return false;
}