// SPDX-License-Identifier: GPL-2.0-only

  /*
   * Copyright (c) 2008, Intel Corporation.
   *

   * Author: Alexander Duyck <alexander.h.duyck@intel.com>
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/skbuff.h>
  #include <linux/rtnetlink.h>
  #include <net/netlink.h>
  #include <net/pkt_sched.h>

  #include <net/ip.h>
  #include <net/ipv6.h>
  #include <net/dsfield.h>

  #include <net/pkt_cls.h>

  
  #include <linux/tc_act/tc_skbedit.h>
  #include <net/tc_act/tc_skbedit.h>

  static unsigned int skbedit_net_id;

  static struct tc_action_ops act_skbedit_ops;

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

  {

  	struct tcf_skbedit *d = to_skbedit(a);

  	struct tcf_skbedit_params *params;
  	int action;

  	tcf_lastuse_update(&d->tcf_tm);

  	bstats_cpu_update(this_cpu_ptr(d->common.cpu_bstats), skb);

  	params = rcu_dereference_bh(d->params);

  	action = READ_ONCE(d->tcf_action);
  
  	if (params->flags & SKBEDIT_F_PRIORITY)
  		skb->priority = params->priority;
  	if (params->flags & SKBEDIT_F_INHERITDSFIELD) {

  		int wlen = skb_network_offset(skb);

  		switch (skb_protocol(skb, true)) {

  		case htons(ETH_P_IP):
  			wlen += sizeof(struct iphdr);
  			if (!pskb_may_pull(skb, wlen))
  				goto err;
  			skb->priority = ipv4_get_dsfield(ip_hdr(skb)) >> 2;
  			break;
  
  		case htons(ETH_P_IPV6):
  			wlen += sizeof(struct ipv6hdr);
  			if (!pskb_may_pull(skb, wlen))
  				goto err;
  			skb->priority = ipv6_get_dsfield(ipv6_hdr(skb)) >> 2;
  			break;
  		}
  	}

  	if (params->flags & SKBEDIT_F_QUEUE_MAPPING &&
  	    skb->dev->real_num_tx_queues > params->queue_mapping)
  		skb_set_queue_mapping(skb, params->queue_mapping);
  	if (params->flags & SKBEDIT_F_MARK) {
  		skb->mark &= ~params->mask;
  		skb->mark |= params->mark & params->mask;

  	}

  	if (params->flags & SKBEDIT_F_PTYPE)
  		skb->pkt_type = params->ptype;

  	return action;

  err:

  	qstats_drop_inc(this_cpu_ptr(d->common.cpu_qstats));

  	return TC_ACT_SHOT;

  }

  static void tcf_skbedit_stats_update(struct tc_action *a, u64 bytes,

  				     u64 packets, u64 drops,
  				     u64 lastuse, bool hw)

  {
  	struct tcf_skbedit *d = to_skbedit(a);
  	struct tcf_t *tm = &d->tcf_tm;

  	tcf_action_update_stats(a, bytes, packets, drops, hw);

  	tm->lastuse = max_t(u64, tm->lastuse, lastuse);
  }

  static const struct nla_policy skbedit_policy[TCA_SKBEDIT_MAX + 1] = {
  	[TCA_SKBEDIT_PARMS]		= { .len = sizeof(struct tc_skbedit) },
  	[TCA_SKBEDIT_PRIORITY]		= { .len = sizeof(u32) },
  	[TCA_SKBEDIT_QUEUE_MAPPING]	= { .len = sizeof(u16) },

  	[TCA_SKBEDIT_MARK]		= { .len = sizeof(u32) },

  	[TCA_SKBEDIT_PTYPE]		= { .len = sizeof(u16) },

  	[TCA_SKBEDIT_MASK]		= { .len = sizeof(u32) },

  	[TCA_SKBEDIT_FLAGS]		= { .len = sizeof(u64) },

  };

  static int tcf_skbedit_init(struct net *net, struct nlattr *nla,

  			    struct nlattr *est, struct tc_action **a,

  			    int ovr, int bind, bool rtnl_held,

  			    struct tcf_proto *tp, u32 act_flags,

  			    struct netlink_ext_ack *extack)

  {

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

  	struct tcf_skbedit_params *params_new;

  	struct nlattr *tb[TCA_SKBEDIT_MAX + 1];

  	struct tcf_chain *goto_ch = NULL;

  	struct tc_skbedit *parm;
  	struct tcf_skbedit *d;

  	u32 flags = 0, *priority = NULL, *mark = NULL, *mask = NULL;

  	u16 *queue_mapping = NULL, *ptype = NULL;

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

  	u32 index;

  
  	if (nla == NULL)
  		return -EINVAL;

  	err = nla_parse_nested_deprecated(tb, TCA_SKBEDIT_MAX, nla,
  					  skbedit_policy, NULL);

  	if (err < 0)
  		return err;
  
  	if (tb[TCA_SKBEDIT_PARMS] == NULL)
  		return -EINVAL;
  
  	if (tb[TCA_SKBEDIT_PRIORITY] != NULL) {
  		flags |= SKBEDIT_F_PRIORITY;
  		priority = nla_data(tb[TCA_SKBEDIT_PRIORITY]);
  	}
  
  	if (tb[TCA_SKBEDIT_QUEUE_MAPPING] != NULL) {
  		flags |= SKBEDIT_F_QUEUE_MAPPING;
  		queue_mapping = nla_data(tb[TCA_SKBEDIT_QUEUE_MAPPING]);
  	}

  	if (tb[TCA_SKBEDIT_PTYPE] != NULL) {
  		ptype = nla_data(tb[TCA_SKBEDIT_PTYPE]);
  		if (!skb_pkt_type_ok(*ptype))
  			return -EINVAL;
  		flags |= SKBEDIT_F_PTYPE;
  	}

  	if (tb[TCA_SKBEDIT_MARK] != NULL) {
  		flags |= SKBEDIT_F_MARK;
  		mark = nla_data(tb[TCA_SKBEDIT_MARK]);
  	}

  	if (tb[TCA_SKBEDIT_MASK] != NULL) {
  		flags |= SKBEDIT_F_MASK;
  		mask = nla_data(tb[TCA_SKBEDIT_MASK]);
  	}

  	if (tb[TCA_SKBEDIT_FLAGS] != NULL) {
  		u64 *pure_flags = nla_data(tb[TCA_SKBEDIT_FLAGS]);
  
  		if (*pure_flags & SKBEDIT_F_INHERITDSFIELD)
  			flags |= SKBEDIT_F_INHERITDSFIELD;
  	}

  	parm = nla_data(tb[TCA_SKBEDIT_PARMS]);

  	index = parm->index;
  	err = tcf_idr_check_alloc(tn, &index, a, bind);

  	if (err < 0)
  		return err;
  	exists = err;

  	if (exists && bind)
  		return 0;
  
  	if (!flags) {

  		if (exists)
  			tcf_idr_release(*a, bind);

  		else

  			tcf_idr_cleanup(tn, index);

  		return -EINVAL;
  	}
  
  	if (!exists) {

  		ret = tcf_idr_create(tn, index, est, a,

  				     &act_skbedit_ops, bind, true, 0);

  		if (ret) {

  			tcf_idr_cleanup(tn, index);

  			return ret;

  		}

  		d = to_skbedit(*a);

  		ret = ACT_P_CREATED;
  	} else {

  		d = to_skbedit(*a);

  		if (!ovr) {
  			tcf_idr_release(*a, bind);

  			return -EEXIST;

  		}

  	}

  	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
  	if (err < 0)
  		goto release_idr;

  	params_new = kzalloc(sizeof(*params_new), GFP_KERNEL);
  	if (unlikely(!params_new)) {

  		err = -ENOMEM;
  		goto put_chain;

  	}
  
  	params_new->flags = flags;

  	if (flags & SKBEDIT_F_PRIORITY)

  		params_new->priority = *priority;

  	if (flags & SKBEDIT_F_QUEUE_MAPPING)

  		params_new->queue_mapping = *queue_mapping;

  	if (flags & SKBEDIT_F_MARK)

  		params_new->mark = *mark;

  	if (flags & SKBEDIT_F_PTYPE)

  		params_new->ptype = *ptype;

  	/* default behaviour is to use all the bits */

  	params_new->mask = 0xffffffff;

  	if (flags & SKBEDIT_F_MASK)

  		params_new->mask = *mask;

  	spin_lock_bh(&d->tcf_lock);

  	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);

  	params_new = rcu_replace_pointer(d->params, params_new,
  					 lockdep_is_held(&d->tcf_lock));

  	spin_unlock_bh(&d->tcf_lock);
  	if (params_new)
  		kfree_rcu(params_new, rcu);

  	if (goto_ch)
  		tcf_chain_put_by_act(goto_ch);

  	return ret;

  put_chain:
  	if (goto_ch)
  		tcf_chain_put_by_act(goto_ch);
  release_idr:
  	tcf_idr_release(*a, bind);
  	return err;

  }

  static int tcf_skbedit_dump(struct sk_buff *skb, struct tc_action *a,
  			    int bind, int ref)

  {
  	unsigned char *b = skb_tail_pointer(skb);

  	struct tcf_skbedit *d = to_skbedit(a);

  	struct tcf_skbedit_params *params;

  	struct tc_skbedit opt = {
  		.index   = d->tcf_index,

  		.refcnt  = refcount_read(&d->tcf_refcnt) - ref,
  		.bindcnt = atomic_read(&d->tcf_bindcnt) - bind,

  	};

  	u64 pure_flags = 0;

  	struct tcf_t t;

  	spin_lock_bh(&d->tcf_lock);
  	params = rcu_dereference_protected(d->params,
  					   lockdep_is_held(&d->tcf_lock));
  	opt.action = d->tcf_action;

  	if (nla_put(skb, TCA_SKBEDIT_PARMS, sizeof(opt), &opt))
  		goto nla_put_failure;

  	if ((params->flags & SKBEDIT_F_PRIORITY) &&
  	    nla_put_u32(skb, TCA_SKBEDIT_PRIORITY, params->priority))

  		goto nla_put_failure;

  	if ((params->flags & SKBEDIT_F_QUEUE_MAPPING) &&
  	    nla_put_u16(skb, TCA_SKBEDIT_QUEUE_MAPPING, params->queue_mapping))

  		goto nla_put_failure;

  	if ((params->flags & SKBEDIT_F_MARK) &&
  	    nla_put_u32(skb, TCA_SKBEDIT_MARK, params->mark))

  		goto nla_put_failure;

  	if ((params->flags & SKBEDIT_F_PTYPE) &&
  	    nla_put_u16(skb, TCA_SKBEDIT_PTYPE, params->ptype))

  		goto nla_put_failure;

  	if ((params->flags & SKBEDIT_F_MASK) &&
  	    nla_put_u32(skb, TCA_SKBEDIT_MASK, params->mask))

  		goto nla_put_failure;

  	if (params->flags & SKBEDIT_F_INHERITDSFIELD)

  		pure_flags |= SKBEDIT_F_INHERITDSFIELD;
  	if (pure_flags != 0 &&
  	    nla_put(skb, TCA_SKBEDIT_FLAGS, sizeof(pure_flags), &pure_flags))
  		goto nla_put_failure;

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

  	if (nla_put_64bit(skb, TCA_SKBEDIT_TM, sizeof(t), &t, TCA_SKBEDIT_PAD))

  		goto nla_put_failure;

  	spin_unlock_bh(&d->tcf_lock);

  	return skb->len;
  
  nla_put_failure:

  	spin_unlock_bh(&d->tcf_lock);

  	nlmsg_trim(skb, b);
  	return -1;
  }

  static void tcf_skbedit_cleanup(struct tc_action *a)
  {
  	struct tcf_skbedit *d = to_skbedit(a);
  	struct tcf_skbedit_params *params;
  
  	params = rcu_dereference_protected(d->params, 1);
  	if (params)
  		kfree_rcu(params, rcu);
  }

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

  			      const struct tc_action_ops *ops,
  			      struct netlink_ext_ack *extack)

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

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

  }

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

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

  	return tcf_idr_search(tn, a, index);

  }

  static size_t tcf_skbedit_get_fill_size(const struct tc_action *act)
  {
  	return nla_total_size(sizeof(struct tc_skbedit))
  		+ nla_total_size(sizeof(u32)) /* TCA_SKBEDIT_PRIORITY */
  		+ nla_total_size(sizeof(u16)) /* TCA_SKBEDIT_QUEUE_MAPPING */
  		+ nla_total_size(sizeof(u32)) /* TCA_SKBEDIT_MARK */
  		+ nla_total_size(sizeof(u16)) /* TCA_SKBEDIT_PTYPE */
  		+ nla_total_size(sizeof(u32)) /* TCA_SKBEDIT_MASK */
  		+ nla_total_size_64bit(sizeof(u64)); /* TCA_SKBEDIT_FLAGS */
  }

  static struct tc_action_ops act_skbedit_ops = {
  	.kind		=	"skbedit",

  	.id		=	TCA_ID_SKBEDIT,

  	.owner		=	THIS_MODULE,

  	.act		=	tcf_skbedit_act,

  	.stats_update	=	tcf_skbedit_stats_update,

  	.dump		=	tcf_skbedit_dump,

  	.init		=	tcf_skbedit_init,

  	.cleanup	=	tcf_skbedit_cleanup,

  	.walk		=	tcf_skbedit_walker,

  	.get_fill_size	=	tcf_skbedit_get_fill_size,

  	.lookup		=	tcf_skbedit_search,

  	.size		=	sizeof(struct tcf_skbedit),

  };
  
  static __net_init int skbedit_init_net(struct net *net)
  {
  	struct tc_action_net *tn = net_generic(net, skbedit_net_id);

  	return tc_action_net_init(net, tn, &act_skbedit_ops);

  }

  static void __net_exit skbedit_exit_net(struct list_head *net_list)

  {

  	tc_action_net_exit(net_list, skbedit_net_id);

  }
  
  static struct pernet_operations skbedit_net_ops = {
  	.init = skbedit_init_net,

  	.exit_batch = skbedit_exit_net,

  	.id   = &skbedit_net_id,
  	.size = sizeof(struct tc_action_net),

  };
  
  MODULE_AUTHOR("Alexander Duyck, <alexander.h.duyck@intel.com>");
  MODULE_DESCRIPTION("SKB Editing");
  MODULE_LICENSE("GPL");
  
  static int __init skbedit_init_module(void)
  {

  	return tcf_register_action(&act_skbedit_ops, &skbedit_net_ops);

  }
  
  static void __exit skbedit_cleanup_module(void)
  {

  	tcf_unregister_action(&act_skbedit_ops, &skbedit_net_ops);

  }
  
  module_init(skbedit_init_module);
  module_exit(skbedit_cleanup_module);