From d03a45572efa068fa64db211d6d45222660e76c5 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Tue, 19 Dec 2017 15:17:13 +0100 Subject: [PATCH] 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: 5f9ae3d9e7e4a ("ipv4: do metrics match when looking up and deleting a route") Signed-off-by: Phil Sutter Signed-off-by: David S. Miller --- net/ipv4/fib_semantics.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index f04d944f8abe..c586597da20d 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -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; }