/*
   * Copyright (c) 2014 Jiri Pirko <jiri@resnulli.us>
   *
   * 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/module.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/skbuff.h>
  #include <linux/rtnetlink.h>
  #include <linux/if_vlan.h>
  #include <net/netlink.h>
  #include <net/pkt_sched.h>
  
  #include <linux/tc_act/tc_vlan.h>
  #include <net/tc_act/tc_vlan.h>
  
  #define VLAN_TAB_MASK     15

  static int vlan_net_id;

  static struct tc_action_ops act_vlan_ops;

  static int tcf_vlan(struct sk_buff *skb, const struct tc_action *a,
  		    struct tcf_result *res)
  {

  	struct tcf_vlan *v = to_vlan(a);

  	int action;
  	int err;

  	u16 tci;

  
  	spin_lock(&v->tcf_lock);

  	tcf_lastuse_update(&v->tcf_tm);

  	bstats_update(&v->tcf_bstats, skb);
  	action = v->tcf_action;

  	/* Ensure 'data' points at mac_header prior calling vlan manipulating
  	 * functions.
  	 */
  	if (skb_at_tc_ingress(skb))
  		skb_push_rcsum(skb, skb->mac_len);

  	switch (v->tcfv_action) {
  	case TCA_VLAN_ACT_POP:
  		err = skb_vlan_pop(skb);
  		if (err)
  			goto drop;
  		break;
  	case TCA_VLAN_ACT_PUSH:

  		err = skb_vlan_push(skb, v->tcfv_push_proto, v->tcfv_push_vid |
  				    (v->tcfv_push_prio << VLAN_PRIO_SHIFT));

  		if (err)
  			goto drop;
  		break;

  	case TCA_VLAN_ACT_MODIFY:
  		/* No-op if no vlan tag (either hw-accel or in-payload) */
  		if (!skb_vlan_tagged(skb))
  			goto unlock;
  		/* extract existing tag (and guarantee no hw-accel tag) */
  		if (skb_vlan_tag_present(skb)) {
  			tci = skb_vlan_tag_get(skb);
  			skb->vlan_tci = 0;
  		} else {
  			/* in-payload vlan tag, pop it */
  			err = __skb_vlan_pop(skb, &tci);
  			if (err)
  				goto drop;
  		}
  		/* replace the vid */
  		tci = (tci & ~VLAN_VID_MASK) | v->tcfv_push_vid;
  		/* replace prio bits, if tcfv_push_prio specified */
  		if (v->tcfv_push_prio) {
  			tci &= ~VLAN_PRIO_MASK;
  			tci |= v->tcfv_push_prio << VLAN_PRIO_SHIFT;
  		}
  		/* put updated tci as hwaccel tag */
  		__vlan_hwaccel_put_tag(skb, v->tcfv_push_proto, tci);
  		break;

  	default:
  		BUG();
  	}
  
  	goto unlock;
  
  drop:
  	action = TC_ACT_SHOT;
  	v->tcf_qstats.drops++;
  unlock:

  	if (skb_at_tc_ingress(skb))
  		skb_pull_rcsum(skb, skb->mac_len);

  	spin_unlock(&v->tcf_lock);
  	return action;
  }
  
  static const struct nla_policy vlan_policy[TCA_VLAN_MAX + 1] = {
  	[TCA_VLAN_PARMS]		= { .len = sizeof(struct tc_vlan) },
  	[TCA_VLAN_PUSH_VLAN_ID]		= { .type = NLA_U16 },
  	[TCA_VLAN_PUSH_VLAN_PROTOCOL]	= { .type = NLA_U16 },

  	[TCA_VLAN_PUSH_VLAN_PRIORITY]	= { .type = NLA_U8 },

  };
  
  static int tcf_vlan_init(struct net *net, struct nlattr *nla,

  			 struct nlattr *est, struct tc_action **a,

  			 int ovr, int bind)
  {

  	struct tc_action_net *tn = net_generic(net, vlan_net_id);

  	struct nlattr *tb[TCA_VLAN_MAX + 1];
  	struct tc_vlan *parm;
  	struct tcf_vlan *v;
  	int action;
  	__be16 push_vid = 0;
  	__be16 push_proto = 0;

  	u8 push_prio = 0;

  	bool exists = false;
  	int ret = 0, err;

  
  	if (!nla)
  		return -EINVAL;
  
  	err = nla_parse_nested(tb, TCA_VLAN_MAX, nla, vlan_policy);
  	if (err < 0)
  		return err;
  
  	if (!tb[TCA_VLAN_PARMS])
  		return -EINVAL;
  	parm = nla_data(tb[TCA_VLAN_PARMS]);

  	exists = tcf_hash_check(tn, parm->index, a, bind);
  	if (exists && bind)
  		return 0;

  	switch (parm->v_action) {
  	case TCA_VLAN_ACT_POP:
  		break;
  	case TCA_VLAN_ACT_PUSH:

  	case TCA_VLAN_ACT_MODIFY:

  		if (!tb[TCA_VLAN_PUSH_VLAN_ID]) {
  			if (exists)

  				tcf_hash_release(*a, bind);

  			return -EINVAL;

  		}

  		push_vid = nla_get_u16(tb[TCA_VLAN_PUSH_VLAN_ID]);

  		if (push_vid >= VLAN_VID_MASK) {
  			if (exists)

  				tcf_hash_release(*a, bind);

  			return -ERANGE;

  		}

  
  		if (tb[TCA_VLAN_PUSH_VLAN_PROTOCOL]) {
  			push_proto = nla_get_be16(tb[TCA_VLAN_PUSH_VLAN_PROTOCOL]);
  			switch (push_proto) {
  			case htons(ETH_P_8021Q):
  			case htons(ETH_P_8021AD):
  				break;
  			default:
  				return -EPROTONOSUPPORT;
  			}
  		} else {
  			push_proto = htons(ETH_P_8021Q);
  		}

  
  		if (tb[TCA_VLAN_PUSH_VLAN_PRIORITY])
  			push_prio = nla_get_u8(tb[TCA_VLAN_PUSH_VLAN_PRIORITY]);

  		break;
  	default:

  		if (exists)

  			tcf_hash_release(*a, bind);

  		return -EINVAL;
  	}
  	action = parm->v_action;

  	if (!exists) {

  		ret = tcf_hash_create(tn, parm->index, est, a,

  				      &act_vlan_ops, bind, false);

  		if (ret)
  			return ret;
  
  		ret = ACT_P_CREATED;
  	} else {

  		tcf_hash_release(*a, bind);

  		if (!ovr)
  			return -EEXIST;
  	}

  	v = to_vlan(*a);

  
  	spin_lock_bh(&v->tcf_lock);
  
  	v->tcfv_action = action;
  	v->tcfv_push_vid = push_vid;

  	v->tcfv_push_prio = push_prio;

  	v->tcfv_push_proto = push_proto;
  
  	v->tcf_action = parm->action;
  
  	spin_unlock_bh(&v->tcf_lock);
  
  	if (ret == ACT_P_CREATED)

  		tcf_hash_insert(tn, *a);

  	return ret;
  }
  
  static int tcf_vlan_dump(struct sk_buff *skb, struct tc_action *a,
  			 int bind, int ref)
  {
  	unsigned char *b = skb_tail_pointer(skb);

  	struct tcf_vlan *v = to_vlan(a);

  	struct tc_vlan opt = {
  		.index    = v->tcf_index,
  		.refcnt   = v->tcf_refcnt - ref,
  		.bindcnt  = v->tcf_bindcnt - bind,
  		.action   = v->tcf_action,
  		.v_action = v->tcfv_action,
  	};
  	struct tcf_t t;
  
  	if (nla_put(skb, TCA_VLAN_PARMS, sizeof(opt), &opt))
  		goto nla_put_failure;

  	if ((v->tcfv_action == TCA_VLAN_ACT_PUSH ||
  	     v->tcfv_action == TCA_VLAN_ACT_MODIFY) &&

  	    (nla_put_u16(skb, TCA_VLAN_PUSH_VLAN_ID, v->tcfv_push_vid) ||

  	     nla_put_be16(skb, TCA_VLAN_PUSH_VLAN_PROTOCOL,

  			  v->tcfv_push_proto) ||
  	     (nla_put_u8(skb, TCA_VLAN_PUSH_VLAN_PRIORITY,
  					      v->tcfv_push_prio))))

  		goto nla_put_failure;

  	tcf_tm_dump(&t, &v->tcf_tm);

  	if (nla_put_64bit(skb, TCA_VLAN_TM, sizeof(t), &t, TCA_VLAN_PAD))

  		goto nla_put_failure;
  	return skb->len;
  
  nla_put_failure:
  	nlmsg_trim(skb, b);
  	return -1;
  }

  static int tcf_vlan_walker(struct net *net, struct sk_buff *skb,
  			   struct netlink_callback *cb, int type,

  			   const struct tc_action_ops *ops)

  {
  	struct tc_action_net *tn = net_generic(net, vlan_net_id);

  	return tcf_generic_walker(tn, skb, cb, type, ops);

  }

  static int tcf_vlan_search(struct net *net, struct tc_action **a, u32 index)

  {
  	struct tc_action_net *tn = net_generic(net, vlan_net_id);
  
  	return tcf_hash_search(tn, a, index);
  }

  static struct tc_action_ops act_vlan_ops = {
  	.kind		=	"vlan",
  	.type		=	TCA_ACT_VLAN,
  	.owner		=	THIS_MODULE,
  	.act		=	tcf_vlan,
  	.dump		=	tcf_vlan_dump,
  	.init		=	tcf_vlan_init,

  	.walk		=	tcf_vlan_walker,
  	.lookup		=	tcf_vlan_search,

  	.size		=	sizeof(struct tcf_vlan),

  };
  
  static __net_init int vlan_init_net(struct net *net)
  {
  	struct tc_action_net *tn = net_generic(net, vlan_net_id);
  
  	return tc_action_net_init(tn, &act_vlan_ops, VLAN_TAB_MASK);
  }
  
  static void __net_exit vlan_exit_net(struct net *net)
  {
  	struct tc_action_net *tn = net_generic(net, vlan_net_id);
  
  	tc_action_net_exit(tn);
  }
  
  static struct pernet_operations vlan_net_ops = {
  	.init = vlan_init_net,
  	.exit = vlan_exit_net,
  	.id   = &vlan_net_id,
  	.size = sizeof(struct tc_action_net),

  };
  
  static int __init vlan_init_module(void)
  {

  	return tcf_register_action(&act_vlan_ops, &vlan_net_ops);

  }
  
  static void __exit vlan_cleanup_module(void)
  {

  	tcf_unregister_action(&act_vlan_ops, &vlan_net_ops);

  }
  
  module_init(vlan_init_module);
  module_exit(vlan_cleanup_module);
  
  MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
  MODULE_DESCRIPTION("vlan manipulation actions");
  MODULE_LICENSE("GPL v2");