Commit f8337efa authored by Petr Machata's avatar Petr Machata Committed by Jakub Kicinski
Browse files

vxlan: Support MC routing in the underlay 



Locally-generated MC packets have so far not been subject to MC routing.
Instead an MC-enabled installation would maintain the MC routing tables,
and separately from that the list of interfaces to send packets to as part
of the VXLAN FDB and MDB.

In a previous patch, a ip_mr_output() and ip6_mr_output() routines were
added for IPv4 and IPv6. All locally generated MC traffic is now passed
through these functions. For reasons of backward compatibility, an SKB
(IPCB / IP6CB) flag guards the actual MC routing.

This patch adds logic to set the flag, and the UAPI to enable the behavior.

Signed-off-by: default avatarPetr Machata <petrm@nvidia.com>
Reviewed-by: default avatarIdo Schimmel <idosch@nvidia.com>
Reviewed-by: default avatarNikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/d899655bb7e9b2521ee8c793e67056b9fd02ba12.1750113335.git.petrm@nvidia.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 96e8f5a9

drivers/net/vxlan/vxlan_core.c

+20 −2
Original line number Diff line number Diff line
@@ -2451,6 +2451,7 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, 
	rcu_read_lock();

	if (addr_family == AF_INET) {

		struct vxlan_sock *sock4 = rcu_dereference(vxlan->vn4_sock);

		u16 ipcb_flags = 0;

		struct rtable *rt;

		__be16 df = 0;

		__be32 saddr;
@@ -2467,6 +2468,9 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, 
			goto tx_error;

		}



		if (flags & VXLAN_F_MC_ROUTE)

			ipcb_flags |= IPSKB_MCROUTE;



		if (!info) {

			/* Bypass encapsulation if the destination is local */

			err = encap_bypass_if_local(skb, dev, vxlan, AF_INET,
@@ -2522,11 +2526,13 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, 


		udp_tunnel_xmit_skb(rt, sock4->sock->sk, skb, saddr,

				    pkey->u.ipv4.dst, tos, ttl, df,

				    src_port, dst_port, xnet, !udp_sum, 0);

				    src_port, dst_port, xnet, !udp_sum,

				    ipcb_flags);

#if IS_ENABLED(CONFIG_IPV6)

	} else {

		struct vxlan_sock *sock6 = rcu_dereference(vxlan->vn6_sock);

		struct in6_addr saddr;

		u16 ip6cb_flags = 0;



		if (!ifindex)

			ifindex = sock6->sock->sk->sk_bound_dev_if;
@@ -2542,6 +2548,9 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, 
			goto tx_error;

		}



		if (flags & VXLAN_F_MC_ROUTE)

			ip6cb_flags |= IP6SKB_MCROUTE;



		if (!info) {

			u32 rt6i_flags = dst_rt6_info(ndst)->rt6i_flags;
@@ -2587,7 +2596,7 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, 
		udp_tunnel6_xmit_skb(ndst, sock6->sock->sk, skb, dev,

				     &saddr, &pkey->u.ipv6.dst, tos, ttl,

				     pkey->label, src_port, dst_port, !udp_sum,

				     0);

				     ip6cb_flags);

#endif

	}

	vxlan_vnifilter_count(vxlan, vni, NULL, VXLAN_VNI_STATS_TX, pkt_len);
@@ -3402,6 +3411,7 @@ static const struct nla_policy vxlan_policy[IFLA_VXLAN_MAX + 1] = { 
	[IFLA_VXLAN_LOCALBYPASS]	= NLA_POLICY_MAX(NLA_U8, 1),

	[IFLA_VXLAN_LABEL_POLICY]       = NLA_POLICY_MAX(NLA_U32, VXLAN_LABEL_MAX),

	[IFLA_VXLAN_RESERVED_BITS] = NLA_POLICY_EXACT_LEN(sizeof(struct vxlanhdr)),

	[IFLA_VXLAN_MC_ROUTE]		= NLA_POLICY_MAX(NLA_U8, 1),

};



static int vxlan_validate(struct nlattr *tb[], struct nlattr *data[],
@@ -4315,6 +4325,14 @@ static int vxlan_nl2conf(struct nlattr *tb[], struct nlattr *data[], 
			return err;

	}



	if (data[IFLA_VXLAN_MC_ROUTE]) {

		err = vxlan_nl2flag(conf, data, IFLA_VXLAN_MC_ROUTE,

				    VXLAN_F_MC_ROUTE, changelink,

				    true, extack);

		if (err)

			return err;

	}



	if (tb[IFLA_MTU]) {

		if (changelink) {

			NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_MTU],

include/net/vxlan.h

+4 −1
Original line number Diff line number Diff line
@@ -332,6 +332,7 @@ struct vxlan_dev { 
#define VXLAN_F_VNIFILTER               0x20000

#define VXLAN_F_MDB			0x40000

#define VXLAN_F_LOCALBYPASS		0x80000

#define VXLAN_F_MC_ROUTE		0x100000



/* Flags that are used in the receive path. These flags must match in

 * order for a socket to be shareable
@@ -353,7 +354,9 @@ struct vxlan_dev { 
					 VXLAN_F_UDP_ZERO_CSUM6_RX |	\

					 VXLAN_F_COLLECT_METADATA  |	\

					 VXLAN_F_VNIFILTER         |    \

					 VXLAN_F_LOCALBYPASS)

					 VXLAN_F_LOCALBYPASS       |	\

					 VXLAN_F_MC_ROUTE          |	\

					 0)



struct net_device *vxlan_dev_create(struct net *net, const char *name,

				    u8 name_assign_type, struct vxlan_config *conf);

include/uapi/linux/if_link.h

+1 −0
Original line number Diff line number Diff line
@@ -1398,6 +1398,7 @@ enum { 
	IFLA_VXLAN_LOCALBYPASS,

	IFLA_VXLAN_LABEL_POLICY, /* IPv6 flow label policy; ifla_vxlan_label_policy */

	IFLA_VXLAN_RESERVED_BITS,

	IFLA_VXLAN_MC_ROUTE,

	__IFLA_VXLAN_MAX

};

#define IFLA_VXLAN_MAX	(__IFLA_VXLAN_MAX - 1)