net: sched: add erspan option support to act_tunnel_key

This patch is to allow setting erspan options using the
act_tunnel_key action. Different from geneve options,
only one option can be set. And also, geneve options,
vxlan options or erspan options can't be set at the
same time.

Options are expressed as ver:index:dir:hwid, when ver
is set to 1, index will be applied while dir and hwid
will be ignored, and when ver is set to 2, dir and
hwid will be used while index will be ignored.

# ip link add name erspan1 type erspan external
# tc qdisc add dev eth0 ingress
# tc filter add dev eth0 protocol ip parent ffff: \
flower indev eth0 \
ip_proto udp \
action tunnel_key \
set src_ip 10.0.99.192 \
dst_ip 10.0.99.193 \
dst_port 6081 \
id 11 \
erspan_opts 1:2:0:0 \
action mirred egress redirect dev erspan1

v1->v2:
- do the validation when dst is not yet allocated as Jakub suggested.
- use Duplicate instead of Wrong in err msg for extack.

Signed-off-by: Xin Long <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/uapi/linux/tc_act/tc_tunnel_key.h

···
 						 * TCA_TUNNEL_KEY_ENC_OPTS_
 						 * attributes
 						 */
+	TCA_TUNNEL_KEY_ENC_OPTS_ERSPAN,		/* Nested
+						 * TCA_TUNNEL_KEY_ENC_OPTS_
+						 * attributes
+						 */
 	__TCA_TUNNEL_KEY_ENC_OPTS_MAX,
 };
 
···
 
 #define TCA_TUNNEL_KEY_ENC_OPT_VXLAN_MAX \
 	(__TCA_TUNNEL_KEY_ENC_OPT_VXLAN_MAX - 1)
+
+enum {
+	TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_UNSPEC,
+	TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_VER,		/* u8 */
+	TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_INDEX,		/* be32 */
+	TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_DIR,		/* u8 */
+	TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_HWID,		/* u8 */
+	__TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_MAX,
+};
+
+#define TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_MAX \
+	(__TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_MAX - 1)
 
 #endif

net/sched/act_tunnel_key.c

···
 #include <linux/rtnetlink.h>
 #include <net/geneve.h>
 #include <net/vxlan.h>
+#include <net/erspan.h>
 #include <net/netlink.h>
 #include <net/pkt_sched.h>
 #include <net/dst.h>
···
 		.strict_start_type = TCA_TUNNEL_KEY_ENC_OPTS_VXLAN },
 	[TCA_TUNNEL_KEY_ENC_OPTS_GENEVE]	= { .type = NLA_NESTED },
 	[TCA_TUNNEL_KEY_ENC_OPTS_VXLAN]		= { .type = NLA_NESTED },
+	[TCA_TUNNEL_KEY_ENC_OPTS_ERSPAN]	= { .type = NLA_NESTED },
 };
 
 static const struct nla_policy
···
 static const struct nla_policy
 vxlan_opt_policy[TCA_TUNNEL_KEY_ENC_OPT_VXLAN_MAX + 1] = {
 	[TCA_TUNNEL_KEY_ENC_OPT_VXLAN_GBP]	   = { .type = NLA_U32 },
+};
+
+static const struct nla_policy
+erspan_opt_policy[TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_MAX + 1] = {
+	[TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_VER]	   = { .type = NLA_U8 },
+	[TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_INDEX]	   = { .type = NLA_U32 },
+	[TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_DIR]	   = { .type = NLA_U8 },
+	[TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_HWID]	   = { .type = NLA_U8 },
 };
 
 static int
···
 	return sizeof(struct vxlan_metadata);
 }
 
+static int
+tunnel_key_copy_erspan_opt(const struct nlattr *nla, void *dst, int dst_len,
+			   struct netlink_ext_ack *extack)
+{
+	struct nlattr *tb[TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_MAX + 1];
+	int err;
+	u8 ver;
+
+	err = nla_parse_nested(tb, TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_MAX, nla,
+			       erspan_opt_policy, extack);
+	if (err < 0)
+		return err;
+
+	if (!tb[TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_VER]) {
+		NL_SET_ERR_MSG(extack, "Missing tunnel key erspan option ver");
+		return -EINVAL;
+	}
+
+	ver = nla_get_u8(tb[TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_VER]);
+	if (ver == 1) {
+		if (!tb[TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_INDEX]) {
+			NL_SET_ERR_MSG(extack, "Missing tunnel key erspan option index");
+			return -EINVAL;
+		}
+	} else if (ver == 2) {
+		if (!tb[TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_DIR] ||
+		    !tb[TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_HWID]) {
+			NL_SET_ERR_MSG(extack, "Missing tunnel key erspan option dir or hwid");
+			return -EINVAL;
+		}
+	} else {
+		NL_SET_ERR_MSG(extack, "Tunnel key erspan option ver is incorrect");
+		return -EINVAL;
+	}
+
+	if (dst) {
+		struct erspan_metadata *md = dst;
+
+		md->version = ver;
+		if (ver == 1) {
+			nla = tb[TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_INDEX];
+			md->u.index = nla_get_be32(nla);
+		} else {
+			nla = tb[TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_DIR];
+			md->u.md2.dir = nla_get_u8(nla);
+			nla = tb[TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_HWID];
+			set_hwid(&md->u.md2, nla_get_u8(nla));
+		}
+	}
+
+	return sizeof(struct erspan_metadata);
+}
+
 static int tunnel_key_copy_opts(const struct nlattr *nla, u8 *dst,
 				int dst_len, struct netlink_ext_ack *extack)
 {
···
 			opts_len += opt_len;
 			type = TUNNEL_VXLAN_OPT;
 			break;
+		case TCA_TUNNEL_KEY_ENC_OPTS_ERSPAN:
+			if (type) {
+				NL_SET_ERR_MSG(extack, "Duplicate type for erspan options");
+				return -EINVAL;
+			}
+			opt_len = tunnel_key_copy_erspan_opt(attr, dst,
+							     dst_len, extack);
+			if (opt_len < 0)
+				return opt_len;
+			opts_len += opt_len;
+			type = TUNNEL_ERSPAN_OPT;
+			break;
 		}
 	}
 
···
 	case TCA_TUNNEL_KEY_ENC_OPTS_VXLAN:
 #if IS_ENABLED(CONFIG_INET)
 		info->key.tun_flags |= TUNNEL_VXLAN_OPT;
+		return tunnel_key_copy_opts(nla, ip_tunnel_info_opts(info),
+					    opts_len, extack);
+#else
+		return -EAFNOSUPPORT;
+#endif
+	case TCA_TUNNEL_KEY_ENC_OPTS_ERSPAN:
+#if IS_ENABLED(CONFIG_INET)
+		info->key.tun_flags |= TUNNEL_ERSPAN_OPT;
 		return tunnel_key_copy_opts(nla, ip_tunnel_info_opts(info),
 					    opts_len, extack);
 #else
···
 	return 0;
 }
 
+static int tunnel_key_erspan_opts_dump(struct sk_buff *skb,
+				       const struct ip_tunnel_info *info)
+{
+	struct erspan_metadata *md = (struct erspan_metadata *)(info + 1);
+	struct nlattr *start;
+
+	start = nla_nest_start_noflag(skb, TCA_TUNNEL_KEY_ENC_OPTS_ERSPAN);
+	if (!start)
+		return -EMSGSIZE;
+
+	if (nla_put_u8(skb, TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_VER, md->version))
+		goto err;
+
+	if (md->version == 1 &&
+	    nla_put_be32(skb, TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_INDEX, md->u.index))
+		goto err;
+
+	if (md->version == 2 &&
+	    (nla_put_u8(skb, TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_DIR,
+			md->u.md2.dir) ||
+	     nla_put_u8(skb, TCA_TUNNEL_KEY_ENC_OPT_ERSPAN_HWID,
+			get_hwid(&md->u.md2))))
+		goto err;
+
+	nla_nest_end(skb, start);
+	return 0;
+err:
+	nla_nest_cancel(skb, start);
+	return -EMSGSIZE;
+}
+
 static int tunnel_key_opts_dump(struct sk_buff *skb,
 				const struct ip_tunnel_info *info)
 {
···
 			goto err_out;
 	} else if (info->key.tun_flags & TUNNEL_VXLAN_OPT) {
 		err = tunnel_key_vxlan_opts_dump(skb, info);
+		if (err)
+			goto err_out;
+	} else if (info->key.tun_flags & TUNNEL_ERSPAN_OPT) {
+		err = tunnel_key_erspan_opts_dump(skb, info);
 		if (err)
 			goto err_out;
 	} else {