From c0b8c32b1c96afc9b32b717927330025cc1c501e Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Thu, 10 Apr 2008 04:00:28 -0700 Subject: [PATCH] IPV4: use xor rather than multiple ands for route compare The comparison in ip_route_input is a hot path, by recoding the C "and" as bit operations, fewer conditional branches get generated so the code should be faster. Maybe someday Gcc will be smart enough to do this? Signed-off-by: Stephen Hemminger Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/route.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index a1c5b8dbdf..139799f8a8 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2077,12 +2077,12 @@ int ip_route_input(struct sk_buff *skb, __be32 daddr, __be32 saddr, rcu_read_lock(); for (rth = rcu_dereference(rt_hash_table[hash].chain); rth; rth = rcu_dereference(rth->u.dst.rt_next)) { - if (rth->fl.fl4_dst == daddr && - rth->fl.fl4_src == saddr && - rth->fl.iif == iif && - rth->fl.oif == 0 && + if (((rth->fl.fl4_dst ^ daddr) | + (rth->fl.fl4_src ^ saddr) | + (rth->fl.iif ^ iif) | + rth->fl.oif | + (rth->fl.fl4_tos ^ tos)) == 0 && rth->fl.mark == skb->mark && - rth->fl.fl4_tos == tos && net_eq(dev_net(rth->u.dst.dev), net) && rth->rt_genid == atomic_read(&rt_genid)) { dst_use(&rth->u.dst, jiffies); -- 2.39.5