bridge: per vlan dst_metadata netlink support

This patch adds support to attach per vlan tunnel info dst
metadata. This enables bridge driver to map vlan to tunnel_info
at ingress and egress. It uses the kernel dst_metadata infrastructure.

The initial use case is vlan to vni bridging, but the api is generic
to extend to any tunnel_info in the future:
    - Uapi to configure/unconfigure/dump per vlan tunnel data
    - netlink functions to configure vlan and tunnel_info mapping
    - Introduces bridge port flag BR_LWT_VLAN to enable attach/detach
    dst_metadata to bridged packets on ports. off by default.
    - changes to existing code is mainly refactor some existing vlan
    handling netlink code + hooks for new vlan tunnel code
    - I have kept the vlan tunnel code isolated in separate files.
    - most of the netlink vlan tunnel code is handling of vlan-tunid
    ranges (follows the vlan range handling code). To conserve space
    vlan-tunid by default are always dumped in ranges if applicable.

Use case:
example use for this is a vxlan bridging gateway or vtep
which maps vlans to vn-segments (or vnis).

iproute2 example (patched and pruned iproute2 output to just show
relevant fdb entries):
example shows same host mac learnt on two vni's and
vlan 100 maps to vni 1000, vlan 101 maps to vni 1001

before (netdev per vni):
$bridge fdb show | grep "00:02:00:00:00:03"
00:02:00:00:00:03 dev vxlan1001 vlan 101 master bridge
00:02:00:00:00:03 dev vxlan1001 dst 12.0.0.8 self
00:02:00:00:00:03 dev vxlan1000 vlan 100 master bridge
00:02:00:00:00:03 dev vxlan1000 dst 12.0.0.8 self

after this patch with collect metdata in bridged mode (single netdev):
$bridge fdb show | grep "00:02:00:00:00:03"
00:02:00:00:00:03 dev vxlan0 vlan 101 master bridge
00:02:00:00:00:03 dev vxlan0 src_vni 1001 dst 12.0.0.8 self
00:02:00:00:00:03 dev vxlan0 vlan 100 master bridge
00:02:00:00:00:03 dev vxlan0 src_vni 1000 dst 12.0.0.8 self

CC: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 296 insertions, 0 deletions

diff --git a/net/bridge/br_netlink_tunnel.c b/net/bridge/br_netlink_tunnel.c
new file mode 100644
index 000000000000..99c68012c9d4
--- /dev/null
+++ b/net/bridge/br_netlink_tunnel.c
@@ -0,0 +1,296 @@
+/*
+ *	Bridge per vlan tunnel port dst_metadata netlink control interface
+ *
+ *	Authors:
+ *	Roopa Prabhu		<roopa@cumulusnetworks.com>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/etherdevice.h>
+#include <net/rtnetlink.h>
+#include <net/net_namespace.h>
+#include <net/sock.h>
+#include <uapi/linux/if_bridge.h>
+#include <net/dst_metadata.h>
+
+#include "br_private.h"
+#include "br_private_tunnel.h"
+
+static size_t __get_vlan_tinfo_size(void)
+{
+	return nla_total_size(0) + /* nest IFLA_BRIDGE_VLAN_TUNNEL_INFO */
+		  nla_total_size(sizeof(u32)) + /* IFLA_BRIDGE_VLAN_TUNNEL_ID */
+		  nla_total_size(sizeof(u16)) + /* IFLA_BRIDGE_VLAN_TUNNEL_VID */
+		  nla_total_size(sizeof(u16)); /* IFLA_BRIDGE_VLAN_TUNNEL_FLAGS */
+}
+
+static bool vlan_tunnel_id_isrange(struct net_bridge_vlan *v,
+				   struct net_bridge_vlan *v_end)
+{
+	__be32 tunid_curr = tunnel_id_to_key32(v->tinfo.tunnel_id);
+	__be32 tunid_end = tunnel_id_to_key32(v_end->tinfo.tunnel_id);
+
+	return (be32_to_cpu(tunid_curr) - be32_to_cpu(tunid_end)) == 1;
+}
+
+static int __get_num_vlan_tunnel_infos(struct net_bridge_vlan_group *vg)
+{
+	struct net_bridge_vlan *v, *v_start = NULL, *v_end = NULL;
+	int num_tinfos = 0;
+
+	/* Count number of vlan infos */
+	list_for_each_entry_rcu(v, &vg->vlan_list, vlist) {
+		/* only a context, bridge vlan not activated */
+		if (!br_vlan_should_use(v) || !v->tinfo.tunnel_id)
+			continue;
+
+		if (!v_start) {
+			goto initvars;
+		} else if ((v->vid - v_end->vid) == 1 &&
+			   vlan_tunnel_id_isrange(v_end, v) == 1) {
+			v_end = v;
+			continue;
+		} else {
+			if ((v_end->vid - v->vid) > 0 &&
+			    vlan_tunnel_id_isrange(v_end, v) > 0)
+				num_tinfos += 2;
+			else
+				num_tinfos += 1;
+		}
+initvars:
+		v_start = v;
+		v_end = v;
+	}
+
+	if (v_start) {
+		if ((v_end->vid - v->vid) > 0 &&
+		    vlan_tunnel_id_isrange(v_end, v) > 0)
+			num_tinfos += 2;
+		else
+			num_tinfos += 1;
+	}
+
+	return num_tinfos;
+}
+
+int br_get_vlan_tunnel_info_size(struct net_bridge_vlan_group *vg)
+{
+	int num_tinfos;
+
+	if (!vg)
+		return 0;
+
+	rcu_read_lock();
+	num_tinfos = __get_num_vlan_tunnel_infos(vg);
+	rcu_read_unlock();
+
+	return num_tinfos * __get_vlan_tinfo_size();
+}
+
+static int br_fill_vlan_tinfo(struct sk_buff *skb, u16 vid,
+			      __be64 tunnel_id, u16 flags)
+{
+	__be32 tid = tunnel_id_to_key32(tunnel_id);
+	struct nlattr *tmap;
+
+	tmap = nla_nest_start(skb, IFLA_BRIDGE_VLAN_TUNNEL_INFO);
+	if (!tmap)
+		return -EMSGSIZE;
+	if (nla_put_u32(skb, IFLA_BRIDGE_VLAN_TUNNEL_ID,
+			be32_to_cpu(tid)))
+		goto nla_put_failure;
+	if (nla_put_u16(skb, IFLA_BRIDGE_VLAN_TUNNEL_VID,
+			vid))
+		goto nla_put_failure;
+	if (nla_put_u16(skb, IFLA_BRIDGE_VLAN_TUNNEL_FLAGS,
+			flags))
+		goto nla_put_failure;
+	nla_nest_end(skb, tmap);
+
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(skb, tmap);
+
+	return -EMSGSIZE;
+}
+
+static int br_fill_vlan_tinfo_range(struct sk_buff *skb,
+				    struct net_bridge_vlan *vtbegin,
+				    struct net_bridge_vlan *vtend)
+{
+	int err;
+
+	if (vtbegin && vtend && (vtend->vid - vtbegin->vid) > 0) {
+		/* add range to skb */
+		err = br_fill_vlan_tinfo(skb, vtbegin->vid,
+					 vtbegin->tinfo.tunnel_id,
+					 BRIDGE_VLAN_INFO_RANGE_BEGIN);
+		if (err)
+			return err;
+
+		err = br_fill_vlan_tinfo(skb, vtend->vid,
+					 vtend->tinfo.tunnel_id,
+					 BRIDGE_VLAN_INFO_RANGE_END);
+		if (err)
+			return err;
+	} else {
+		err = br_fill_vlan_tinfo(skb, vtbegin->vid,
+					 vtbegin->tinfo.tunnel_id,
+					 0);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+int br_fill_vlan_tunnel_info(struct sk_buff *skb,
+			     struct net_bridge_vlan_group *vg)
+{
+	struct net_bridge_vlan *vtbegin = NULL;
+	struct net_bridge_vlan *vtend = NULL;
+	struct net_bridge_vlan *v;
+	int err;
+
+	/* Count number of vlan infos */
+	list_for_each_entry_rcu(v, &vg->vlan_list, vlist) {
+		/* only a context, bridge vlan not activated */
+		if (!br_vlan_should_use(v))
+			continue;
+
+		if (!v->tinfo.tunnel_dst)
+			continue;
+
+		if (!vtbegin) {
+			goto initvars;
+		} else if ((v->vid - vtend->vid) == 1 &&
+			    vlan_tunnel_id_isrange(v, vtend)) {
+			vtend = v;
+			continue;
+		} else {
+			err = br_fill_vlan_tinfo_range(skb, vtbegin, vtend);
+			if (err)
+				return err;
+		}
+initvars:
+		vtbegin = v;
+		vtend = v;
+	}
+
+	if (vtbegin) {
+		err = br_fill_vlan_tinfo_range(skb, vtbegin, vtend);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static const struct nla_policy vlan_tunnel_policy[IFLA_BRIDGE_VLAN_TUNNEL_MAX + 1] = {
+	[IFLA_BRIDGE_VLAN_TUNNEL_ID] = { .type = NLA_U32 },
+	[IFLA_BRIDGE_VLAN_TUNNEL_VID] = { .type = NLA_U16 },
+	[IFLA_BRIDGE_VLAN_TUNNEL_FLAGS] = { .type = NLA_U16 },
+};
+
+static int br_vlan_tunnel_info(struct net_bridge_port *p, int cmd,
+			       u16 vid, u32 tun_id)
+{
+	int err = 0;
+
+	if (!p)
+		return -EINVAL;
+
+	switch (cmd) {
+	case RTM_SETLINK:
+		err = nbp_vlan_tunnel_info_add(p, vid, tun_id);
+		break;
+	case RTM_DELLINK:
+		nbp_vlan_tunnel_info_delete(p, vid);
+		break;
+	}
+
+	return err;
+}
+
+int br_parse_vlan_tunnel_info(struct nlattr *attr,
+			      struct vtunnel_info *tinfo)
+{
+	struct nlattr *tb[IFLA_BRIDGE_VLAN_TUNNEL_MAX + 1];
+	u32 tun_id;
+	u16 vid, flags = 0;
+	int err;
+
+	memset(tinfo, 0, sizeof(*tinfo));
+
+	if (!tb[IFLA_BRIDGE_VLAN_TUNNEL_ID] ||
+	    !tb[IFLA_BRIDGE_VLAN_TUNNEL_VID])
+		return -EINVAL;
+
+	err = nla_parse_nested(tb, IFLA_BRIDGE_VLAN_TUNNEL_MAX,
+			       attr, vlan_tunnel_policy);
+	if (err < 0)
+		return err;
+
+	tun_id = nla_get_u32(tb[IFLA_BRIDGE_VLAN_TUNNEL_ID]);
+	vid = nla_get_u16(tb[IFLA_BRIDGE_VLAN_TUNNEL_VID]);
+	if (vid >= VLAN_VID_MASK)
+		return -ERANGE;
+
+	if (tb[IFLA_BRIDGE_VLAN_TUNNEL_FLAGS])
+		flags = nla_get_u16(tb[IFLA_BRIDGE_VLAN_TUNNEL_FLAGS]);
+
+	tinfo->tunid = tun_id;
+	tinfo->vid = vid;
+	tinfo->flags = flags;
+
+	return 0;
+}
+
+int br_process_vlan_tunnel_info(struct net_bridge *br,
+				struct net_bridge_port *p, int cmd,
+				struct vtunnel_info *tinfo_curr,
+				struct vtunnel_info *tinfo_last)
+{
+	int err;
+
+	if (tinfo_curr->flags & BRIDGE_VLAN_INFO_RANGE_BEGIN) {
+		if (tinfo_last->flags & BRIDGE_VLAN_INFO_RANGE_BEGIN)
+			return -EINVAL;
+		memcpy(tinfo_last, tinfo_curr, sizeof(struct vtunnel_info));
+	} else if (tinfo_curr->flags & BRIDGE_VLAN_INFO_RANGE_END) {
+		int t, v;
+
+		if (!(tinfo_last->flags & BRIDGE_VLAN_INFO_RANGE_BEGIN))
+			return -EINVAL;
+		if ((tinfo_curr->vid - tinfo_last->vid) !=
+		    (tinfo_curr->tunid - tinfo_last->tunid))
+			return -EINVAL;
+		t = tinfo_last->tunid;
+		for (v = tinfo_last->vid; v <= tinfo_curr->vid; v++) {
+			err = br_vlan_tunnel_info(p, cmd, v, t);
+			if (err)
+				return err;
+			t++;
+		}
+		memset(tinfo_last, 0, sizeof(struct vtunnel_info));
+		memset(tinfo_curr, 0, sizeof(struct vtunnel_info));
+	} else {
+		if (tinfo_last->flags)
+			return -EINVAL;
+		err = br_vlan_tunnel_info(p, cmd, tinfo_curr->vid,
+					  tinfo_curr->tunid);
+		if (err)
+			return err;
+		memset(tinfo_last, 0, sizeof(struct vtunnel_info));
+		memset(tinfo_curr, 0, sizeof(struct vtunnel_info));
+	}
+
+	return 0;
+}