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Message-ID: <0a199bbf-0ee7-1826-0906-dcfed8c86c7d@gmail.com>
Date: Tue, 11 May 2021 09:46:27 -0600
From: David Ahern <dsahern@...il.com>
To: Ido Schimmel <idosch@...sch.org>, netdev@...r.kernel.org
Cc: davem@...emloft.net, kuba@...nel.org, petrm@...dia.com,
roopa@...dia.com, nikolay@...dia.com, ssuryaextr@...il.com,
mlxsw@...dia.com, Ido Schimmel <idosch@...dia.com>
Subject: Re: [RFC PATCH net-next v2 03/10] ipv4: Add custom multipath hash
policy
On 5/9/21 9:16 AM, Ido Schimmel wrote:
> diff --git a/net/ipv4/route.c b/net/ipv4/route.c
> index 9d61e969446e..a4c477475f4c 100644
> --- a/net/ipv4/route.c
> +++ b/net/ipv4/route.c
> @@ -1906,6 +1906,121 @@ static void ip_multipath_l3_keys(const struct sk_buff *skb,
> hash_keys->addrs.v4addrs.dst = key_iph->daddr;
> }
>
> +static u32 fib_multipath_custom_hash_outer(const struct net *net,
> + const struct sk_buff *skb,
> + bool *p_has_inner)
> +{
> + u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
> + struct flow_keys keys, hash_keys;
> +
> + if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
> + return 0;
> +
> + memset(&hash_keys, 0, sizeof(hash_keys));
> + skb_flow_dissect_flow_keys(skb, &keys, FLOW_DISSECTOR_F_STOP_AT_ENCAP);
> +
> + hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
> + hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
> + hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
> + hash_keys.basic.ip_proto = keys.basic.ip_proto;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
> + hash_keys.ports.src = keys.ports.src;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
> + hash_keys.ports.dst = keys.ports.dst;
> +
> + *p_has_inner = !!(keys.control.flags & FLOW_DIS_ENCAPSULATION);
> + return flow_hash_from_keys(&hash_keys);
> +}
> +
> +static u32 fib_multipath_custom_hash_inner(const struct net *net,
> + const struct sk_buff *skb,
> + bool has_inner)
> +{
> + u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
> + struct flow_keys keys, hash_keys;
> +
> + /* We assume the packet carries an encapsulation, but if none was
> + * encountered during dissection of the outer flow, then there is no
> + * point in calling the flow dissector again.
> + */
> + if (!has_inner)
> + return 0;
> +
> + if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_MASK))
> + return 0;
> +
> + memset(&hash_keys, 0, sizeof(hash_keys));
> + skb_flow_dissect_flow_keys(skb, &keys, 0);
> +
> + if (!(keys.control.flags & FLOW_DIS_ENCAPSULATION))
> + return 0;
> +
> + if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
> + hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
> + hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
> + hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
> + } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
> + hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
> + hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
> + hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL)
> + hash_keys.tags.flow_label = keys.tags.flow_label;
> + }
> +
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO)
> + hash_keys.basic.ip_proto = keys.basic.ip_proto;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT)
> + hash_keys.ports.src = keys.ports.src;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT)
> + hash_keys.ports.dst = keys.ports.dst;
> +
> + return flow_hash_from_keys(&hash_keys);
> +}
> +
> +static u32 fib_multipath_custom_hash_skb(const struct net *net,
> + const struct sk_buff *skb)
> +{
> + u32 mhash, mhash_inner;
> + bool has_inner = true;
> +
Is it not possible to do the dissect once here and pass keys to outer
and inner functions?
memset(&hash_keys, 0, sizeof(hash_keys));
skb_flow_dissect_flow_keys(skb, &keys, flag);
> + mhash = fib_multipath_custom_hash_outer(net, skb, &has_inner);
> + mhash_inner = fib_multipath_custom_hash_inner(net, skb, has_inner);
> +
> + return jhash_2words(mhash, mhash_inner, 0);
> +}
> +
> +static u32 fib_multipath_custom_hash_fl4(const struct net *net,
> + const struct flowi4 *fl4)
> +{
> + u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
> + struct flow_keys hash_keys;
> +
> + if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
> + return 0;
> +
> + memset(&hash_keys, 0, sizeof(hash_keys));
> + hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
> + hash_keys.addrs.v4addrs.src = fl4->saddr;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
> + hash_keys.addrs.v4addrs.dst = fl4->daddr;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
> + hash_keys.basic.ip_proto = fl4->flowi4_proto;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
> + hash_keys.ports.src = fl4->fl4_sport;
> + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
> + hash_keys.ports.dst = fl4->fl4_dport;
> +
> + return flow_hash_from_keys(&hash_keys);
> +}
> +
> /* if skb is set it will be used and fl4 can be NULL */
> int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
> const struct sk_buff *skb, struct flow_keys *flkeys)
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