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Commit 1a66a836 authored by William Tu's avatar William Tu Committed by David S. Miller
Browse files

gre: add collect_md mode to ERSPAN tunnel 



Similar to gre, vxlan, geneve, ipip tunnels, allow ERSPAN tunnels to
operate in 'collect metadata' mode.  bpf_skb_[gs]et_tunnel_key() helpers
can make use of it right away.  OVS can use it as well in the future.

Signed-off-by: default avatarWilliam Tu <u9012063@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 862a03c3

include/net/ip_tunnels.h

+3 −1
Original line number Diff line number Diff line
@@ -154,8 +154,10 @@ struct ip_tunnel { 
#define TUNNEL_GENEVE_OPT	__cpu_to_be16(0x0800)

#define TUNNEL_VXLAN_OPT	__cpu_to_be16(0x1000)

#define TUNNEL_NOCACHE		__cpu_to_be16(0x2000)

#define TUNNEL_ERSPAN_OPT	__cpu_to_be16(0x4000)



#define TUNNEL_OPTIONS_PRESENT	(TUNNEL_GENEVE_OPT | TUNNEL_VXLAN_OPT)

#define TUNNEL_OPTIONS_PRESENT \

		(TUNNEL_GENEVE_OPT | TUNNEL_VXLAN_OPT | TUNNEL_ERSPAN_OPT)



struct tnl_ptk_info {

	__be16 flags;

net/ipv4/ip_gre.c

+98 −4
Original line number Diff line number Diff line
@@ -113,6 +113,8 @@ MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN"); 


static struct rtnl_link_ops ipgre_link_ops __read_mostly;

static int ipgre_tunnel_init(struct net_device *dev);

static void erspan_build_header(struct sk_buff *skb,

				__be32 id, u32 index, bool truncate);



static unsigned int ipgre_net_id __read_mostly;

static unsigned int gre_tap_net_id __read_mostly;
@@ -287,7 +289,33 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi, 
					   false, false) < 0)

			goto drop;



		if (tunnel->collect_md) {

			struct ip_tunnel_info *info;

			struct erspan_metadata *md;

			__be64 tun_id;

			__be16 flags;



			tpi->flags |= TUNNEL_KEY;

			flags = tpi->flags;

			tun_id = key32_to_tunnel_id(tpi->key);



			tun_dst = ip_tun_rx_dst(skb, flags,

						tun_id, sizeof(*md));

			if (!tun_dst)

				return PACKET_REJECT;



			md = ip_tunnel_info_opts(&tun_dst->u.tun_info);

			if (!md)

				return PACKET_REJECT;



			md->index = index;

			info = &tun_dst->u.tun_info;

			info->key.tun_flags |= TUNNEL_ERSPAN_OPT;

			info->options_len = sizeof(*md);

		} else {

			tunnel->index = ntohl(index);

		}



		skb_reset_mac_header(skb);

		ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);

		return PACKET_RCVD;
@@ -523,6 +551,64 @@ static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev, 
	dev->stats.tx_dropped++;

}



static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev,

			   __be16 proto)

{

	struct ip_tunnel *tunnel = netdev_priv(dev);

	struct ip_tunnel_info *tun_info;

	const struct ip_tunnel_key *key;

	struct erspan_metadata *md;

	struct rtable *rt = NULL;

	bool truncate = false;

	struct flowi4 fl;

	int tunnel_hlen;

	__be16 df;



	tun_info = skb_tunnel_info(skb);

	if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||

		     ip_tunnel_info_af(tun_info) != AF_INET))

		goto err_free_skb;



	key = &tun_info->key;



	/* ERSPAN has fixed 8 byte GRE header */

	tunnel_hlen = 8 + sizeof(struct erspanhdr);



	rt = prepare_fb_xmit(skb, dev, &fl, tunnel_hlen);

	if (!rt)

		return;



	if (gre_handle_offloads(skb, false))

		goto err_free_rt;



	if (skb->len > dev->mtu) {

		pskb_trim(skb, dev->mtu);

		truncate = true;

	}



	md = ip_tunnel_info_opts(tun_info);

	if (!md)

		goto err_free_rt;



	erspan_build_header(skb, tunnel_id_to_key32(key->tun_id),

			    ntohl(md->index), truncate);



	gre_build_header(skb, 8, TUNNEL_SEQ,

			 htons(ETH_P_ERSPAN), 0, htonl(tunnel->o_seqno++));



	df = key->tun_flags & TUNNEL_DONT_FRAGMENT ?  htons(IP_DF) : 0;



	iptunnel_xmit(skb->sk, rt, skb, fl.saddr, key->u.ipv4.dst, IPPROTO_GRE,

		      key->tos, key->ttl, df, false);

	return;



err_free_rt:

	ip_rt_put(rt);

err_free_skb:

	kfree_skb(skb);

	dev->stats.tx_dropped++;

}



static int gre_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)

{

	struct ip_tunnel_info *info = skb_tunnel_info(skb);
@@ -636,6 +722,11 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb, 
	struct ip_tunnel *tunnel = netdev_priv(dev);

	bool truncate = false;



	if (tunnel->collect_md) {

		erspan_fb_xmit(skb, dev, skb->protocol);

		return NETDEV_TX_OK;

	}



	if (gre_handle_offloads(skb, false))

		goto free_skb;
@@ -998,9 +1089,12 @@ static int erspan_validate(struct nlattr *tb[], struct nlattr *data[], 
		return ret;



	/* ERSPAN should only have GRE sequence and key flag */

	if (data[IFLA_GRE_OFLAGS])

		flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);

	if (data[IFLA_GRE_IFLAGS])

		flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);

	if (flags != (GRE_SEQ | GRE_KEY))

	if (!data[IFLA_GRE_COLLECT_METADATA] &&

	    flags != (GRE_SEQ | GRE_KEY))

		return -EINVAL;



	/* ERSPAN Session ID only has 10-bit. Since we reuse