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Date: Sun, 9 May 2021 18:16:07 +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 02/10] ipv4: 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.ipv4.fib_multipath_hash_fields=0x0037
net.ipv4.fib_multipath_hash_fields = 0x0037
The kernel rejects unknown fields, for example:
# sysctl -w net.ipv4.fib_multipath_hash_fields=0x1000
sysctl: setting key "net.ipv4.fib_multipath_hash_fields": Invalid argument
More fields can be added in the future, if needed.
Signed-off-by: Ido Schimmel <idosch@...dia.com>
---
Documentation/networking/ip-sysctl.rst | 27 ++++++++++++++++
include/net/ip_fib.h | 43 ++++++++++++++++++++++++++
include/net/netns/ipv4.h | 1 +
net/ipv4/fib_frontend.c | 6 ++++
net/ipv4/sysctl_net_ipv4.c | 11 +++++++
5 files changed, 88 insertions(+)
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index c2ecc9894fd0..15982f830abc 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -100,6 +100,33 @@ fib_multipath_hash_policy - INTEGER
- 1 - Layer 4
- 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 Unused
+ 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)
+
fib_sync_mem - UNSIGNED INTEGER
Amount of dirty memory from fib entries that can be backlogged before
synchronize_rcu is forced.
diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index a914f33f3ed5..3ab2563b1a23 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -466,6 +466,49 @@ int fib_sync_up(struct net_device *dev, unsigned char nh_flags);
void fib_sync_mtu(struct net_device *dev, u32 orig_mtu);
void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig);
+/* Fields used for sysctl_fib_multipath_hash_fields.
+ * Common to IPv4 and IPv6.
+ *
+ * Add new fields at the end. This is user API.
+ */
+#define FIB_MULTIPATH_HASH_FIELD_SRC_IP BIT(0)
+#define FIB_MULTIPATH_HASH_FIELD_DST_IP BIT(1)
+#define FIB_MULTIPATH_HASH_FIELD_IP_PROTO BIT(2)
+#define FIB_MULTIPATH_HASH_FIELD_FLOWLABEL BIT(3)
+#define FIB_MULTIPATH_HASH_FIELD_SRC_PORT BIT(4)
+#define FIB_MULTIPATH_HASH_FIELD_DST_PORT BIT(5)
+#define FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP BIT(6)
+#define FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP BIT(7)
+#define FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO BIT(8)
+#define FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL BIT(9)
+#define FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT BIT(10)
+#define FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT BIT(11)
+
+#define FIB_MULTIPATH_HASH_FIELD_OUTER_MASK \
+ (FIB_MULTIPATH_HASH_FIELD_SRC_IP | \
+ FIB_MULTIPATH_HASH_FIELD_DST_IP | \
+ FIB_MULTIPATH_HASH_FIELD_IP_PROTO | \
+ FIB_MULTIPATH_HASH_FIELD_FLOWLABEL | \
+ FIB_MULTIPATH_HASH_FIELD_SRC_PORT | \
+ FIB_MULTIPATH_HASH_FIELD_DST_PORT)
+
+#define FIB_MULTIPATH_HASH_FIELD_INNER_MASK \
+ (FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP | \
+ FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP | \
+ FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO | \
+ FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL | \
+ FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT | \
+ FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT)
+
+#define FIB_MULTIPATH_HASH_FIELD_ALL_MASK \
+ (FIB_MULTIPATH_HASH_FIELD_OUTER_MASK | \
+ FIB_MULTIPATH_HASH_FIELD_INNER_MASK)
+
+#define FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK \
+ (FIB_MULTIPATH_HASH_FIELD_SRC_IP | \
+ FIB_MULTIPATH_HASH_FIELD_DST_IP | \
+ FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
+
#ifdef CONFIG_IP_ROUTE_MULTIPATH
int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
const struct sk_buff *skb, struct flow_keys *flkeys);
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index f6af8d96d3c6..746c80cd4257 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -210,6 +210,7 @@ struct netns_ipv4 {
#endif
#endif
#ifdef CONFIG_IP_ROUTE_MULTIPATH
+ u32 sysctl_fib_multipath_hash_fields;
u8 sysctl_fib_multipath_use_neigh;
u8 sysctl_fib_multipath_hash_policy;
#endif
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 84bb707bd88d..129213b7d834 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1516,6 +1516,12 @@ static int __net_init ip_fib_net_init(struct net *net)
if (err)
return err;
+#ifdef CONFIG_IP_ROUTE_MULTIPATH
+ /* Default to 3-tuple */
+ net->ipv4.sysctl_fib_multipath_hash_fields =
+ FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK;
+#endif
+
/* Avoid false sharing : Use at least a full cache line */
size = max_t(size_t, size, L1_CACHE_BYTES);
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index a62934b9f15a..da627c4d633a 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -19,6 +19,7 @@
#include <net/snmp.h>
#include <net/icmp.h>
#include <net/ip.h>
+#include <net/ip_fib.h>
#include <net/route.h>
#include <net/tcp.h>
#include <net/udp.h>
@@ -48,6 +49,8 @@ static int ip_ping_group_range_min[] = { 0, 0 };
static int ip_ping_group_range_max[] = { GID_T_MAX, GID_T_MAX };
static u32 u32_max_div_HZ = UINT_MAX / HZ;
static int one_day_secs = 24 * 3600;
+static u32 fib_multipath_hash_fields_all_mask __maybe_unused =
+ FIB_MULTIPATH_HASH_FIELD_ALL_MASK;
/* obsolete */
static int sysctl_tcp_low_latency __read_mostly;
@@ -1052,6 +1055,14 @@ static struct ctl_table ipv4_net_table[] = {
.extra1 = SYSCTL_ZERO,
.extra2 = &two,
},
+ {
+ .procname = "fib_multipath_hash_fields",
+ .data = &init_net.ipv4.sysctl_fib_multipath_hash_fields,
+ .maxlen = sizeof(u32),
+ .mode = 0644,
+ .proc_handler = proc_douintvec_minmax,
+ .extra2 = &fib_multipath_hash_fields_all_mask,
+ },
#endif
{
.procname = "ip_unprivileged_port_start",
--
2.31.1
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