From 398958ae48f44bb036d0fa9829cd489270bf1fc2 Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Tue, 9 Jan 2018 16:40:28 +0200 Subject: [PATCH] ipv6: Add support for non-equal-cost multipath The use of hash-threshold instead of modulo-N makes it trivial to add support for non-equal-cost multipath. Instead of dividing the multipath hash function's output space equally between the nexthops, each nexthop is assigned a region size which is proportional to its weight. Signed-off-by: Ido Schimmel Acked-by: David Ahern Signed-off-by: David S. Miller --- include/net/ip6_fib.h | 1 + net/ipv6/route.c | 11 +++++++---- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h index 97cd05d87780..34ec321d6a03 100644 --- a/include/net/ip6_fib.h +++ b/include/net/ip6_fib.h @@ -171,6 +171,7 @@ struct rt6_info { u32 rt6i_metric; u32 rt6i_pmtu; /* more non-fragment space at head required */ + int rt6i_nh_weight; unsigned short rt6i_nfheader_len; u8 rt6i_protocol; u8 exception_bucket_flushed:1, diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 7837b8c754a3..1076ae0ea9d5 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2594,6 +2594,7 @@ static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg, #endif rt->rt6i_metric = cfg->fc_metric; + rt->rt6i_nh_weight = 1; /* We cannot add true routes via loopback here, they would result in kernel looping; promote them to reject routes @@ -3507,11 +3508,11 @@ static int rt6_multipath_total_weight(const struct rt6_info *rt) int total = 0; if (!rt6_is_dead(rt)) - total++; + total += rt->rt6i_nh_weight; list_for_each_entry(iter, &rt->rt6i_siblings, rt6i_siblings) { if (!rt6_is_dead(iter)) - total++; + total += iter->rt6i_nh_weight; } return total; @@ -3522,7 +3523,7 @@ static void rt6_upper_bound_set(struct rt6_info *rt, int *weight, int total) int upper_bound = -1; if (!rt6_is_dead(rt)) { - (*weight)++; + *weight += rt->rt6i_nh_weight; upper_bound = DIV_ROUND_CLOSEST_ULL((u64) (*weight) << 31, total) - 1; } @@ -4024,6 +4025,8 @@ static int ip6_route_multipath_add(struct fib6_config *cfg, goto cleanup; } + rt->rt6i_nh_weight = rtnh->rtnh_hops + 1; + err = ip6_route_info_append(&rt6_nh_list, rt, &r_cfg); if (err) { dst_release_immediate(&rt->dst); @@ -4246,7 +4249,7 @@ static int rt6_add_nexthop(struct sk_buff *skb, struct rt6_info *rt) if (!rtnh) goto nla_put_failure; - rtnh->rtnh_hops = 0; + rtnh->rtnh_hops = rt->rt6i_nh_weight - 1; rtnh->rtnh_ifindex = rt->dst.dev ? rt->dst.dev->ifindex : 0; if (rt6_nexthop_info(skb, rt, &flags, true) < 0) -- 2.30.2