// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   * net/sched/cls_fw.c	Classifier mapping ipchains' fwmark to traffic class.
   *

   * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   *
   * Changes:
   * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_walk off by one
   * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_delete killed all the filter (and kernel).
   * Alex <alex@pilotsoft.com> : 2004xxyy: Added Action extension

   */

  #include <linux/module.h>

  #include <linux/slab.h>

  #include <linux/types.h>
  #include <linux/kernel.h>

  #include <linux/string.h>

  #include <linux/errno.h>

  #include <linux/skbuff.h>

  #include <net/netlink.h>

  #include <net/act_api.h>
  #include <net/pkt_cls.h>

  #include <net/sch_generic.h>

  #define HTSIZE 256

  struct fw_head {

  	u32			mask;

  	struct fw_filter __rcu	*ht[HTSIZE];
  	struct rcu_head		rcu;

  };

  struct fw_filter {

  	struct fw_filter __rcu	*next;

  	u32			id;
  	struct tcf_result	res;

  	int			ifindex;

  	struct tcf_exts		exts;

  	struct tcf_proto	*tp;

  	struct rcu_work		rwork;

  };

  static u32 fw_hash(u32 handle)

  {

  	handle ^= (handle >> 16);
  	handle ^= (handle >> 8);
  	return handle % HTSIZE;

  }

  static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,

  		       struct tcf_result *res)

  {

  	struct fw_head *head = rcu_dereference_bh(tp->root);

  	struct fw_filter *f;
  	int r;

  	u32 id = skb->mark;

  
  	if (head != NULL) {

  		id &= head->mask;

  
  		for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
  		     f = rcu_dereference_bh(f->next)) {

  			if (f->id == id) {
  				*res = f->res;

  				if (!tcf_match_indev(skb, f->ifindex))

  					continue;

  				r = tcf_exts_exec(skb, &f->exts, res);
  				if (r < 0)
  					continue;
  
  				return r;
  			}
  		}
  	} else {

  		struct Qdisc *q = tcf_block_q(tp->chain->block);

  		/* Old method: classify the packet using its skb mark. */

  		if (id && (TC_H_MAJ(id) == 0 ||

  			   !(TC_H_MAJ(id ^ q->handle)))) {

  			res->classid = id;
  			res->class = 0;
  			return 0;
  		}
  	}
  
  	return -1;
  }

  static void *fw_get(struct tcf_proto *tp, u32 handle)

  {

  	struct fw_head *head = rtnl_dereference(tp->root);

  	struct fw_filter *f;
  
  	if (head == NULL)

  		return NULL;

  	f = rtnl_dereference(head->ht[fw_hash(handle)]);
  	for (; f; f = rtnl_dereference(f->next)) {

  		if (f->id == handle)

  			return f;

  	}

  	return NULL;

  }

  static int fw_init(struct tcf_proto *tp)
  {

  	/* We don't allocate fw_head here, because in the old method
  	 * we don't need it at all.
  	 */

  	return 0;
  }

  static void __fw_delete_filter(struct fw_filter *f)
  {
  	tcf_exts_destroy(&f->exts);
  	tcf_exts_put_net(&f->exts);
  	kfree(f);
  }

  static void fw_delete_filter_work(struct work_struct *work)

  {

  	struct fw_filter *f = container_of(to_rcu_work(work),
  					   struct fw_filter,
  					   rwork);

  	rtnl_lock();

  	__fw_delete_filter(f);

  	rtnl_unlock();
  }

  static void fw_destroy(struct tcf_proto *tp, bool rtnl_held,
  		       struct netlink_ext_ack *extack)

  {

  	struct fw_head *head = rtnl_dereference(tp->root);

  	struct fw_filter *f;
  	int h;
  
  	if (head == NULL)

  		return;

  	for (h = 0; h < HTSIZE; h++) {

  		while ((f = rtnl_dereference(head->ht[h])) != NULL) {
  			RCU_INIT_POINTER(head->ht[h],
  					 rtnl_dereference(f->next));

  			tcf_unbind_filter(tp, &f->res);

  			if (tcf_exts_get_net(&f->exts))

  				tcf_queue_work(&f->rwork, fw_delete_filter_work);

  			else
  				__fw_delete_filter(f);

  		}
  	}

  	kfree_rcu(head, rcu);

  }

  static int fw_delete(struct tcf_proto *tp, void *arg, bool *last,

  		     bool rtnl_held, struct netlink_ext_ack *extack)

  {

  	struct fw_head *head = rtnl_dereference(tp->root);

  	struct fw_filter *f = arg;

  	struct fw_filter __rcu **fp;
  	struct fw_filter *pfp;

  	int ret = -EINVAL;
  	int h;

  
  	if (head == NULL || f == NULL)
  		goto out;

  	fp = &head->ht[fw_hash(f->id)];
  
  	for (pfp = rtnl_dereference(*fp); pfp;
  	     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
  		if (pfp == f) {
  			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));

  			tcf_unbind_filter(tp, &f->res);

  			tcf_exts_get_net(&f->exts);

  			tcf_queue_work(&f->rwork, fw_delete_filter_work);

  			ret = 0;
  			break;

  		}
  	}

  
  	*last = true;
  	for (h = 0; h < HTSIZE; h++) {
  		if (rcu_access_pointer(head->ht[h])) {
  			*last = false;
  			break;
  		}
  	}

  out:

  	return ret;

  }

  static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
  	[TCA_FW_CLASSID]	= { .type = NLA_U32 },
  	[TCA_FW_INDEV]		= { .type = NLA_STRING, .len = IFNAMSIZ },
  	[TCA_FW_MASK]		= { .type = NLA_U32 },
  };

  static int fw_set_parms(struct net *net, struct tcf_proto *tp,
  			struct fw_filter *f, struct nlattr **tb,

  			struct nlattr **tca, unsigned long base, bool ovr,
  			struct netlink_ext_ack *extack)

  {

  	struct fw_head *head = rtnl_dereference(tp->root);

  	u32 mask;

  	int err;

  	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr,

  				true, extack);

  	if (err < 0)
  		return err;

  	if (tb[TCA_FW_CLASSID]) {

  		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);

  		tcf_bind_filter(tp, &f->res, base);
  	}

  	if (tb[TCA_FW_INDEV]) {

  		int ret;

  		ret = tcf_change_indev(net, tb[TCA_FW_INDEV], extack);

  		if (ret < 0)
  			return ret;

  		f->ifindex = ret;

  	}

  	err = -EINVAL;

  	if (tb[TCA_FW_MASK]) {

  		mask = nla_get_u32(tb[TCA_FW_MASK]);

  		if (mask != head->mask)

  			return err;

  	} else if (head->mask != 0xFFFFFFFF)

  		return err;

  
  	return 0;

  }

  static int fw_change(struct net *net, struct sk_buff *in_skb,

  		     struct tcf_proto *tp, unsigned long base,

  		     u32 handle, struct nlattr **tca, void **arg,

  		     bool ovr, bool rtnl_held,
  		     struct netlink_ext_ack *extack)

  {

  	struct fw_head *head = rtnl_dereference(tp->root);

  	struct fw_filter *f = *arg;

  	struct nlattr *opt = tca[TCA_OPTIONS];
  	struct nlattr *tb[TCA_FW_MAX + 1];

  	int err;
  
  	if (!opt)

  		return handle ? -EINVAL : 0; /* Succeed if it is old method. */

  	err = nla_parse_nested_deprecated(tb, TCA_FW_MAX, opt, fw_policy,
  					  NULL);

  	if (err < 0)
  		return err;

  	if (f) {
  		struct fw_filter *pfp, *fnew;
  		struct fw_filter __rcu **fp;

  		if (f->id != handle && handle)
  			return -EINVAL;

  
  		fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
  		if (!fnew)
  			return -ENOBUFS;
  
  		fnew->id = f->id;
  		fnew->res = f->res;

  		fnew->ifindex = f->ifindex;

  		fnew->tp = f->tp;

  		err = tcf_exts_init(&fnew->exts, net, TCA_FW_ACT,
  				    TCA_FW_POLICE);

  		if (err < 0) {
  			kfree(fnew);
  			return err;
  		}

  		err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr, extack);

  		if (err < 0) {

  			tcf_exts_destroy(&fnew->exts);

  			kfree(fnew);
  			return err;
  		}
  
  		fp = &head->ht[fw_hash(fnew->id)];
  		for (pfp = rtnl_dereference(*fp); pfp;
  		     fp = &pfp->next, pfp = rtnl_dereference(*fp))
  			if (pfp == f)
  				break;
  
  		RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
  		rcu_assign_pointer(*fp, fnew);

  		tcf_unbind_filter(tp, &f->res);

  		tcf_exts_get_net(&f->exts);

  		tcf_queue_work(&f->rwork, fw_delete_filter_work);

  		*arg = fnew;

  		return err;

  	}
  
  	if (!handle)
  		return -EINVAL;

  	if (!head) {
  		u32 mask = 0xFFFFFFFF;

  		if (tb[TCA_FW_MASK])

  			mask = nla_get_u32(tb[TCA_FW_MASK]);
  
  		head = kzalloc(sizeof(*head), GFP_KERNEL);
  		if (!head)
  			return -ENOBUFS;
  		head->mask = mask;
  
  		rcu_assign_pointer(tp->root, head);

  	}

  	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);

  	if (f == NULL)
  		return -ENOBUFS;

  	err = tcf_exts_init(&f->exts, net, TCA_FW_ACT, TCA_FW_POLICE);

  	if (err < 0)
  		goto errout;

  	f->id = handle;

  	f->tp = tp;

  	err = fw_set_parms(net, tp, f, tb, tca, base, ovr, extack);

  	if (err < 0)
  		goto errout;

  	RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
  	rcu_assign_pointer(head->ht[fw_hash(handle)], f);

  	*arg = f;

  	return 0;
  
  errout:

  	tcf_exts_destroy(&f->exts);

  	kfree(f);

  	return err;
  }

  static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg,
  		    bool rtnl_held)

  {

  	struct fw_head *head = rtnl_dereference(tp->root);

  	int h;

  	if (head == NULL)
  		arg->stop = 1;
  
  	if (arg->stop)

  		return;

  	for (h = 0; h < HTSIZE; h++) {

  		struct fw_filter *f;

  		for (f = rtnl_dereference(head->ht[h]); f;
  		     f = rtnl_dereference(f->next)) {

  			if (arg->count < arg->skip) {
  				arg->count++;
  				continue;
  			}

  			if (arg->fn(tp, f, arg) < 0) {

  				arg->stop = 1;
  				return;
  			}
  			arg->count++;
  		}
  	}
  }

  static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,

  		   struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)

  {

  	struct fw_head *head = rtnl_dereference(tp->root);

  	struct fw_filter *f = fh;

  	struct nlattr *nest;

  
  	if (f == NULL)
  		return skb->len;
  
  	t->tcm_handle = f->id;

  	if (!f->res.classid && !tcf_exts_has_actions(&f->exts))

  		return skb->len;

  	nest = nla_nest_start_noflag(skb, TCA_OPTIONS);

  	if (nest == NULL)
  		goto nla_put_failure;

  	if (f->res.classid &&
  	    nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
  		goto nla_put_failure;

  	if (f->ifindex) {
  		struct net_device *dev;
  		dev = __dev_get_by_index(net, f->ifindex);
  		if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
  			goto nla_put_failure;
  	}

  	if (head->mask != 0xFFFFFFFF &&
  	    nla_put_u32(skb, TCA_FW_MASK, head->mask))
  		goto nla_put_failure;

  	if (tcf_exts_dump(skb, &f->exts) < 0)

  		goto nla_put_failure;

  	nla_nest_end(skb, nest);

  	if (tcf_exts_dump_stats(skb, &f->exts) < 0)

  		goto nla_put_failure;

  
  	return skb->len;

  nla_put_failure:

  	nla_nest_cancel(skb, nest);

  	return -1;
  }

  static void fw_bind_class(void *fh, u32 classid, unsigned long cl, void *q,
  			  unsigned long base)

  {
  	struct fw_filter *f = fh;

  	if (f && f->res.classid == classid) {
  		if (cl)
  			__tcf_bind_filter(q, &f->res, base);
  		else
  			__tcf_unbind_filter(q, &f->res);
  	}

  }

  static struct tcf_proto_ops cls_fw_ops __read_mostly = {

  	.kind		=	"fw",
  	.classify	=	fw_classify,
  	.init		=	fw_init,
  	.destroy	=	fw_destroy,
  	.get		=	fw_get,

  	.change		=	fw_change,
  	.delete		=	fw_delete,
  	.walk		=	fw_walk,
  	.dump		=	fw_dump,

  	.bind_class	=	fw_bind_class,

  	.owner		=	THIS_MODULE,
  };
  
  static int __init init_fw(void)
  {
  	return register_tcf_proto_ops(&cls_fw_ops);
  }

  static void __exit exit_fw(void)

  {
  	unregister_tcf_proto_ops(&cls_fw_ops);
  }
  
  module_init(init_fw)
  module_exit(exit_fw)
  MODULE_LICENSE("GPL");