From 73c2c5cbb15a8a82d5bea52594b0beb038963bcc Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Mon, 17 May 2021 21:15:23 +0300 Subject: [PATCH] ipv6: Add custom multipath hash policy Add a new multipath hash policy where the packet fields used for hash calculation are determined by user space via the fib_multipath_hash_fields sysctl that was introduced in the previous patch. The current set of available packet fields includes both outer and inner fields, which requires two invocations of the flow dissector. Avoid unnecessary dissection of the outer or inner flows by skipping dissection if none of the outer or inner fields are required. In accordance with the existing policies, when an skb is not available, packet fields are extracted from the provided flow key. In which case, only outer fields are considered. Signed-off-by: Ido Schimmel Reviewed-by: David Ahern Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.rst | 2 + net/ipv6/route.c | 125 +++++++++++++++++++++++++ net/ipv6/sysctl_net_ipv6.c | 3 +- 3 files changed, 129 insertions(+), 1 deletion(-) diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index 4246cc4ae35b..a5c250044500 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -1772,6 +1772,8 @@ fib_multipath_hash_policy - INTEGER - 0 - Layer 3 (source and destination addresses plus flow label) - 1 - Layer 4 (standard 5-tuple) - 2 - Layer 3 or inner Layer 3 if present + - 3 - Custom multipath hash. Fields used for multipath hash calculation + are determined by fib_multipath_hash_fields sysctl fib_multipath_hash_fields - UNSIGNED INTEGER When fib_multipath_hash_policy is set to 3 (custom multipath hash), the diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 9935e18146e5..c46889381ae4 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2326,6 +2326,125 @@ static void ip6_multipath_l3_keys(const struct sk_buff *skb, } } +static u32 rt6_multipath_custom_hash_outer(const struct net *net, + const struct sk_buff *skb, + bool *p_has_inner) +{ + u32 hash_fields = ip6_multipath_hash_fields(net); + 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_IPV6_ADDRS; + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP) + hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src; + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP) + hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.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_FLOWLABEL) + hash_keys.tags.flow_label = keys.tags.flow_label; + 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 rt6_multipath_custom_hash_inner(const struct net *net, + const struct sk_buff *skb, + bool has_inner) +{ + u32 hash_fields = ip6_multipath_hash_fields(net); + 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 rt6_multipath_custom_hash_skb(const struct net *net, + const struct sk_buff *skb) +{ + u32 mhash, mhash_inner; + bool has_inner = true; + + mhash = rt6_multipath_custom_hash_outer(net, skb, &has_inner); + mhash_inner = rt6_multipath_custom_hash_inner(net, skb, has_inner); + + return jhash_2words(mhash, mhash_inner, 0); +} + +static u32 rt6_multipath_custom_hash_fl6(const struct net *net, + const struct flowi6 *fl6) +{ + u32 hash_fields = ip6_multipath_hash_fields(net); + 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_IPV6_ADDRS; + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP) + hash_keys.addrs.v6addrs.src = fl6->saddr; + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP) + hash_keys.addrs.v6addrs.dst = fl6->daddr; + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO) + hash_keys.basic.ip_proto = fl6->flowi6_proto; + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_FLOWLABEL) + hash_keys.tags.flow_label = (__force u32)flowi6_get_flowlabel(fl6); + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT) + hash_keys.ports.src = fl6->fl6_sport; + if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT) + hash_keys.ports.dst = fl6->fl6_dport; + + return flow_hash_from_keys(&hash_keys); +} + /* if skb is set it will be used and fl6 can be NULL */ u32 rt6_multipath_hash(const struct net *net, const struct flowi6 *fl6, const struct sk_buff *skb, struct flow_keys *flkeys) @@ -2416,6 +2535,12 @@ u32 rt6_multipath_hash(const struct net *net, const struct flowi6 *fl6, } mhash = flow_hash_from_keys(&hash_keys); break; + case 3: + if (skb) + mhash = rt6_multipath_custom_hash_skb(net, skb); + else + mhash = rt6_multipath_custom_hash_fl6(net, fl6); + break; } return mhash >> 1; diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c index ce23c8f7ceb3..160bea5db973 100644 --- a/net/ipv6/sysctl_net_ipv6.c +++ b/net/ipv6/sysctl_net_ipv6.c @@ -23,6 +23,7 @@ #endif static int two = 2; +static int three = 3; static int flowlabel_reflect_max = 0x7; static int auto_flowlabels_max = IP6_AUTO_FLOW_LABEL_MAX; static u32 rt6_multipath_hash_fields_all_mask = @@ -152,7 +153,7 @@ static struct ctl_table ipv6_table_template[] = { .mode = 0644, .proc_handler = proc_rt6_multipath_hash_policy, .extra1 = SYSCTL_ZERO, - .extra2 = &two, + .extra2 = &three, }, { .procname = "fib_multipath_hash_fields", -- GitLab