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Message-Id: <20210509151615.200608-7-idosch@idosch.org>
Date: Sun, 9 May 2021 18:16:11 +0300
From: Ido Schimmel <idosch@...sch.org>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, kuba@...nel.org, dsahern@...il.com,
petrm@...dia.com, roopa@...dia.com, nikolay@...dia.com,
ssuryaextr@...il.com, mlxsw@...dia.com,
Ido Schimmel <idosch@...dia.com>
Subject: [RFC PATCH net-next v2 06/10] ipv6: Add a sysctl to control multipath hash fields
From: Ido Schimmel <idosch@...dia.com>
A subsequent patch will add a new multipath hash policy where the packet
fields used for multipath hash calculation are determined by user space.
This patch adds a sysctl that allows user space to set these fields.
The packet fields are represented using a bitmask and are common between
IPv4 and IPv6 to allow user space to use the same numbering across both
protocols. For example, to hash based on standard 5-tuple:
# sysctl -w net.ipv6.fib_multipath_hash_fields=0x0037
net.ipv6.fib_multipath_hash_fields = 0x0037
To avoid introducing holes in 'struct netns_sysctl_ipv6', move the
'bindv6only' field after the multipath hash fields.
The kernel rejects unknown fields, for example:
# sysctl -w net.ipv6.fib_multipath_hash_fields=0x1000
sysctl: setting key "net.ipv6.fib_multipath_hash_fields": Invalid argument
Signed-off-by: Ido Schimmel <idosch@...dia.com>
---
Documentation/networking/ip-sysctl.rst | 27 ++++++++++++++++++++++++++
include/net/ipv6.h | 8 ++++++++
include/net/netns/ipv6.h | 3 ++-
net/ipv6/ip6_fib.c | 5 +++++
net/ipv6/sysctl_net_ipv6.c | 11 +++++++++++
5 files changed, 53 insertions(+), 1 deletion(-)
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index 2c3b7677222e..f7ae65524ff3 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -1773,6 +1773,33 @@ fib_multipath_hash_policy - INTEGER
- 1 - Layer 4 (standard 5-tuple)
- 2 - Layer 3 or inner Layer 3 if present
+fib_multipath_hash_fields - UNSIGNED INTEGER
+ When fib_multipath_hash_policy is set to 3 (custom multipath hash), the
+ fields used for multipath hash calculation are determined by this
+ sysctl.
+
+ This value is a bitmask which enables various fields for multipath hash
+ calculation.
+
+ Possible fields are:
+
+ ====== ============================
+ 0x0001 Source IP address
+ 0x0002 Destination IP address
+ 0x0004 IP protocol
+ 0x0008 Flow Label
+ 0x0010 Source port
+ 0x0020 Destination port
+ 0x0040 Inner source IP address
+ 0x0080 Inner destination IP address
+ 0x0100 Inner IP protocol
+ 0x0200 Inner Flow Label
+ 0x0400 Inner source port
+ 0x0800 Inner destination port
+ ====== ============================
+
+ Default: 0x0007 (source IP, destination IP and IP protocol)
+
anycast_src_echo_reply - BOOLEAN
Controls the use of anycast addresses as source addresses for ICMPv6
echo reply
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 448bf2b34759..f2d0ecc257bb 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -926,11 +926,19 @@ static inline int ip6_multipath_hash_policy(const struct net *net)
{
return net->ipv6.sysctl.multipath_hash_policy;
}
+static inline u32 ip6_multipath_hash_fields(const struct net *net)
+{
+ return net->ipv6.sysctl.multipath_hash_fields;
+}
#else
static inline int ip6_multipath_hash_policy(const struct net *net)
{
return 0;
}
+static inline u32 ip6_multipath_hash_fields(const struct net *net)
+{
+ return 0;
+}
#endif
/*
diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
index 6153c8067009..bde0b7adb4a3 100644
--- a/include/net/netns/ipv6.h
+++ b/include/net/netns/ipv6.h
@@ -28,8 +28,9 @@ struct netns_sysctl_ipv6 {
int ip6_rt_gc_elasticity;
int ip6_rt_mtu_expires;
int ip6_rt_min_advmss;
- u8 bindv6only;
+ u32 multipath_hash_fields;
u8 multipath_hash_policy;
+ u8 bindv6only;
u8 flowlabel_consistency;
u8 auto_flowlabels;
int icmpv6_time;
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 33d2d6a4e28c..2d650dc24349 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -32,6 +32,7 @@
#include <net/lwtunnel.h>
#include <net/fib_notifier.h>
+#include <net/ip_fib.h>
#include <net/ip6_fib.h>
#include <net/ip6_route.h>
@@ -2355,6 +2356,10 @@ static int __net_init fib6_net_init(struct net *net)
if (err)
return err;
+ /* Default to 3-tuple */
+ net->ipv6.sysctl.multipath_hash_fields =
+ FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK;
+
spin_lock_init(&net->ipv6.fib6_gc_lock);
rwlock_init(&net->ipv6.fib6_walker_lock);
INIT_LIST_HEAD(&net->ipv6.fib6_walkers);
diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
index 27102c3d6e1d..fb73d9839bc8 100644
--- a/net/ipv6/sysctl_net_ipv6.c
+++ b/net/ipv6/sysctl_net_ipv6.c
@@ -17,6 +17,7 @@
#include <net/addrconf.h>
#include <net/inet_frag.h>
#include <net/netevent.h>
+#include <net/ip_fib.h>
#ifdef CONFIG_NETLABEL
#include <net/calipso.h>
#endif
@@ -24,6 +25,8 @@
static int two = 2;
static int flowlabel_reflect_max = 0x7;
static int auto_flowlabels_max = IP6_AUTO_FLOW_LABEL_MAX;
+static u32 rt6_multipath_hash_fields_all_mask =
+ FIB_MULTIPATH_HASH_FIELD_ALL_MASK;
static int proc_rt6_multipath_hash_policy(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
@@ -151,6 +154,14 @@ static struct ctl_table ipv6_table_template[] = {
.extra1 = SYSCTL_ZERO,
.extra2 = &two,
},
+ {
+ .procname = "fib_multipath_hash_fields",
+ .data = &init_net.ipv6.sysctl.multipath_hash_fields,
+ .maxlen = sizeof(u32),
+ .mode = 0644,
+ .proc_handler = proc_douintvec_minmax,
+ .extra2 = &rt6_multipath_hash_fields_all_mask,
+ },
{
.procname = "seg6_flowlabel",
.data = &init_net.ipv6.sysctl.seg6_flowlabel,
--
2.31.1
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