diff mbox series

[net-next,v4] bonding: add a vlan+srcmac tx hashing option

Message ID 20210119010927.1191922-1-jarod@redhat.com (mailing list archive)
State Accepted
Commit 7b8fc0103bb51d1d3e1fb5fd67958612e709f883
Delegated to: Netdev Maintainers
Headers show
Series [net-next,v4] bonding: add a vlan+srcmac tx hashing option | expand

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netdev/tree_selection success Clearly marked for net-next
netdev/subject_prefix success Link
netdev/cc_maintainers warning 2 maintainers not CCed: corbet@lwn.net linux-doc@vger.kernel.org
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 7149 this patch: 7149
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch warning WARNING: quoted string split across lines
netdev/build_allmodconfig_warn success Errors and warnings before: 7549 this patch: 7549
netdev/header_inline success Link
netdev/stable success Stable not CCed

Commit Message

Jarod Wilson Jan. 19, 2021, 1:09 a.m. UTC
This comes from an end-user request, where they're running multiple VMs on
hosts with bonded interfaces connected to some interest switch topologies,
where 802.3ad isn't an option. They're currently running a proprietary
solution that effectively achieves load-balancing of VMs and bandwidth
utilization improvements with a similar form of transmission algorithm.

Basically, each VM has it's own vlan, so it always sends its traffic out
the same interface, unless that interface fails. Traffic gets split
between the interfaces, maintaining a consistent path, with failover still
available if an interface goes down.

Unlike bond_eth_hash(), this hash function is using the full source MAC
address instead of just the last byte, as there are so few components to
the hash, and in the no-vlan case, we would be returning just the last
byte of the source MAC as the hash value. It's entirely possible to have
two NICs in a bond with the same last byte of their MAC, but not the same
MAC, so this adjustment should guarantee distinct hashes in all cases.

This has been rudimetarily tested to provide similar results to the
proprietary solution it is aiming to replace. A patch for iproute2 is also
posted, to properly support the new mode there as well.

Cc: Jay Vosburgh <j.vosburgh@gmail.com>
Cc: Veaceslav Falico <vfalico@gmail.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Thomas Davis <tadavis@lbl.gov>
Cc: netdev@vger.kernel.org
Signed-off-by: Jarod Wilson <jarod@redhat.com>
---
v2: verified netlink interfaces working, added Documentation, changed
tx hash mode name to vlan+mac for consistency and clarity.
v3: drop inline from hash function, use full source MAC, not just the
last byte, expand explanation in patch description, extend hash name to
vlan+srcmac.
v4: fix documentation issues pointed out by David Ahern

 Documentation/networking/bonding.rst | 13 +++++++++++
 drivers/net/bonding/bond_main.c      | 34 ++++++++++++++++++++++++++--
 drivers/net/bonding/bond_options.c   | 13 ++++++-----
 include/linux/netdevice.h            |  1 +
 include/uapi/linux/if_bonding.h      |  1 +
 5 files changed, 54 insertions(+), 8 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org Jan. 20, 2021, 6:10 a.m. UTC | #1
Hello:

This patch was applied to netdev/net-next.git (refs/heads/master):

On Mon, 18 Jan 2021 20:09:27 -0500 you wrote:
> This comes from an end-user request, where they're running multiple VMs on
> hosts with bonded interfaces connected to some interest switch topologies,
> where 802.3ad isn't an option. They're currently running a proprietary
> solution that effectively achieves load-balancing of VMs and bandwidth
> utilization improvements with a similar form of transmission algorithm.
> 
> Basically, each VM has it's own vlan, so it always sends its traffic out
> the same interface, unless that interface fails. Traffic gets split
> between the interfaces, maintaining a consistent path, with failover still
> available if an interface goes down.
> 
> [...]

Here is the summary with links:
  - [net-next,v4] bonding: add a vlan+srcmac tx hashing option
    https://git.kernel.org/netdev/net-next/c/7b8fc0103bb5

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
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diff mbox series

Patch

diff --git a/Documentation/networking/bonding.rst b/Documentation/networking/bonding.rst
index adc314639085..36562dcd3e1e 100644
--- a/Documentation/networking/bonding.rst
+++ b/Documentation/networking/bonding.rst
@@ -951,6 +951,19 @@  xmit_hash_policy
 		packets will be distributed according to the encapsulated
 		flows.
 
+	vlan+srcmac
+
+		This policy uses a very rudimentary vlan ID and source mac
+		hash to load-balance traffic per-vlan, with failover
+		should one leg fail. The intended use case is for a bond
+		shared by multiple virtual machines, all configured to
+		use their own vlan, to give lacp-like functionality
+		without requiring lacp-capable switching hardware.
+
+		The formula for the hash is simply
+
+		hash = (vlan ID) XOR (source MAC vendor) XOR (source MAC dev)
+
 	The default value is layer2.  This option was added in bonding
 	version 2.6.3.  In earlier versions of bonding, this parameter
 	does not exist, and the layer2 policy is the only policy.  The
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 5fe5232cc3f3..d4bc4d4e953b 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -164,7 +164,7 @@  module_param(xmit_hash_policy, charp, 0);
 MODULE_PARM_DESC(xmit_hash_policy, "balance-alb, balance-tlb, balance-xor, 802.3ad hashing method; "
 				   "0 for layer 2 (default), 1 for layer 3+4, "
 				   "2 for layer 2+3, 3 for encap layer 2+3, "
-				   "4 for encap layer 3+4");
+				   "4 for encap layer 3+4, 5 for vlan+srcmac");
 module_param(arp_interval, int, 0);
 MODULE_PARM_DESC(arp_interval, "arp interval in milliseconds");
 module_param_array(arp_ip_target, charp, NULL, 0);
@@ -1434,6 +1434,8 @@  static enum netdev_lag_hash bond_lag_hash_type(struct bonding *bond,
 		return NETDEV_LAG_HASH_E23;
 	case BOND_XMIT_POLICY_ENCAP34:
 		return NETDEV_LAG_HASH_E34;
+	case BOND_XMIT_POLICY_VLAN_SRCMAC:
+		return NETDEV_LAG_HASH_VLAN_SRCMAC;
 	default:
 		return NETDEV_LAG_HASH_UNKNOWN;
 	}
@@ -3494,6 +3496,27 @@  static bool bond_flow_ip(struct sk_buff *skb, struct flow_keys *fk,
 	return true;
 }
 
+static u32 bond_vlan_srcmac_hash(struct sk_buff *skb)
+{
+	struct ethhdr *mac_hdr = (struct ethhdr *)skb_mac_header(skb);
+	u32 srcmac_vendor = 0, srcmac_dev = 0;
+	u16 vlan;
+	int i;
+
+	for (i = 0; i < 3; i++)
+		srcmac_vendor = (srcmac_vendor << 8) | mac_hdr->h_source[i];
+
+	for (i = 3; i < ETH_ALEN; i++)
+		srcmac_dev = (srcmac_dev << 8) | mac_hdr->h_source[i];
+
+	if (!skb_vlan_tag_present(skb))
+		return srcmac_vendor ^ srcmac_dev;
+
+	vlan = skb_vlan_tag_get(skb);
+
+	return vlan ^ srcmac_vendor ^ srcmac_dev;
+}
+
 /* Extract the appropriate headers based on bond's xmit policy */
 static bool bond_flow_dissect(struct bonding *bond, struct sk_buff *skb,
 			      struct flow_keys *fk)
@@ -3501,10 +3524,14 @@  static bool bond_flow_dissect(struct bonding *bond, struct sk_buff *skb,
 	bool l34 = bond->params.xmit_policy == BOND_XMIT_POLICY_LAYER34;
 	int noff, proto = -1;
 
-	if (bond->params.xmit_policy > BOND_XMIT_POLICY_LAYER23) {
+	switch (bond->params.xmit_policy) {
+	case BOND_XMIT_POLICY_ENCAP23:
+	case BOND_XMIT_POLICY_ENCAP34:
 		memset(fk, 0, sizeof(*fk));
 		return __skb_flow_dissect(NULL, skb, &flow_keys_bonding,
 					  fk, NULL, 0, 0, 0, 0);
+	default:
+		break;
 	}
 
 	fk->ports.ports = 0;
@@ -3556,6 +3583,9 @@  u32 bond_xmit_hash(struct bonding *bond, struct sk_buff *skb)
 	    skb->l4_hash)
 		return skb->hash;
 
+	if (bond->params.xmit_policy == BOND_XMIT_POLICY_VLAN_SRCMAC)
+		return bond_vlan_srcmac_hash(skb);
+
 	if (bond->params.xmit_policy == BOND_XMIT_POLICY_LAYER2 ||
 	    !bond_flow_dissect(bond, skb, &flow))
 		return bond_eth_hash(skb);
diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
index a4e4e15f574d..c69400c5bf07 100644
--- a/drivers/net/bonding/bond_options.c
+++ b/drivers/net/bonding/bond_options.c
@@ -96,12 +96,13 @@  static const struct bond_opt_value bond_pps_tbl[] = {
 };
 
 static const struct bond_opt_value bond_xmit_hashtype_tbl[] = {
-	{ "layer2",   BOND_XMIT_POLICY_LAYER2, BOND_VALFLAG_DEFAULT},
-	{ "layer3+4", BOND_XMIT_POLICY_LAYER34, 0},
-	{ "layer2+3", BOND_XMIT_POLICY_LAYER23, 0},
-	{ "encap2+3", BOND_XMIT_POLICY_ENCAP23, 0},
-	{ "encap3+4", BOND_XMIT_POLICY_ENCAP34, 0},
-	{ NULL,       -1,                       0},
+	{ "layer2",      BOND_XMIT_POLICY_LAYER2,      BOND_VALFLAG_DEFAULT},
+	{ "layer3+4",    BOND_XMIT_POLICY_LAYER34,     0},
+	{ "layer2+3",    BOND_XMIT_POLICY_LAYER23,     0},
+	{ "encap2+3",    BOND_XMIT_POLICY_ENCAP23,     0},
+	{ "encap3+4",    BOND_XMIT_POLICY_ENCAP34,     0},
+	{ "vlan+srcmac", BOND_XMIT_POLICY_VLAN_SRCMAC, 0},
+	{ NULL,          -1,                           0},
 };
 
 static const struct bond_opt_value bond_arp_validate_tbl[] = {
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 5b949076ed23..a94ce80a2fe1 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2615,6 +2615,7 @@  enum netdev_lag_hash {
 	NETDEV_LAG_HASH_L23,
 	NETDEV_LAG_HASH_E23,
 	NETDEV_LAG_HASH_E34,
+	NETDEV_LAG_HASH_VLAN_SRCMAC,
 	NETDEV_LAG_HASH_UNKNOWN,
 };
 
diff --git a/include/uapi/linux/if_bonding.h b/include/uapi/linux/if_bonding.h
index 45f3750aa861..e8eb4ad03cf1 100644
--- a/include/uapi/linux/if_bonding.h
+++ b/include/uapi/linux/if_bonding.h
@@ -94,6 +94,7 @@ 
 #define BOND_XMIT_POLICY_LAYER23	2 /* layer 2+3 (IP ^ MAC) */
 #define BOND_XMIT_POLICY_ENCAP23	3 /* encapsulated layer 2+3 */
 #define BOND_XMIT_POLICY_ENCAP34	4 /* encapsulated layer 3+4 */
+#define BOND_XMIT_POLICY_VLAN_SRCMAC	5 /* vlan + source MAC */
 
 /* 802.3ad port state definitions (43.4.2.2 in the 802.3ad standard) */
 #define LACP_STATE_LACP_ACTIVITY   0x1