/*

   * net/sched/act_pedit.c	Generic packet editor

   *
   *		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.
   *
   * Authors:	Jamal Hadi Salim (2002-4)
   */

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

  #include <linux/string.h>

  #include <linux/errno.h>

  #include <linux/skbuff.h>
  #include <linux/rtnetlink.h>
  #include <linux/module.h>
  #include <linux/init.h>

  #include <linux/slab.h>

  #include <net/netlink.h>

  #include <net/pkt_sched.h>
  #include <linux/tc_act/tc_pedit.h>
  #include <net/tc_act/tc_pedit.h>

  #include <uapi/linux/tc_act/tc_pedit.h>

  static unsigned int pedit_net_id;

  static struct tc_action_ops act_pedit_ops;

  static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {

  	[TCA_PEDIT_PARMS]	= { .len = sizeof(struct tc_pedit) },

  	[TCA_PEDIT_KEYS_EX]   = { .type = NLA_NESTED },

  };

  static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
  	[TCA_PEDIT_KEY_EX_HTYPE]  = { .type = NLA_U16 },

  	[TCA_PEDIT_KEY_EX_CMD]	  = { .type = NLA_U16 },

  };
  
  static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
  							u8 n)
  {
  	struct tcf_pedit_key_ex *keys_ex;
  	struct tcf_pedit_key_ex *k;
  	const struct nlattr *ka;
  	int err = -EINVAL;
  	int rem;
  
  	if (!nla || !n)
  		return NULL;
  
  	keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
  	if (!keys_ex)
  		return ERR_PTR(-ENOMEM);
  
  	k = keys_ex;
  
  	nla_for_each_nested(ka, nla, rem) {
  		struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
  
  		if (!n) {
  			err = -EINVAL;
  			goto err_out;
  		}
  		n--;
  
  		if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
  			err = -EINVAL;
  			goto err_out;
  		}
  
  		err = nla_parse_nested(tb, TCA_PEDIT_KEY_EX_MAX, ka,

  				       pedit_key_ex_policy, NULL);

  		if (err)
  			goto err_out;

  		if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
  		    !tb[TCA_PEDIT_KEY_EX_CMD]) {

  			err = -EINVAL;
  			goto err_out;
  		}
  
  		k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);

  		k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);

  		if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
  		    k->cmd > TCA_PEDIT_CMD_MAX) {

  			err = -EINVAL;
  			goto err_out;
  		}
  
  		k++;
  	}

  	if (n) {
  		err = -EINVAL;

  		goto err_out;

  	}

  
  	return keys_ex;
  
  err_out:
  	kfree(keys_ex);
  	return ERR_PTR(err);
  }
  
  static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
  				 struct tcf_pedit_key_ex *keys_ex, int n)
  {
  	struct nlattr *keys_start = nla_nest_start(skb, TCA_PEDIT_KEYS_EX);

  	if (!keys_start)
  		goto nla_failure;

  	for (; n > 0; n--) {
  		struct nlattr *key_start;
  
  		key_start = nla_nest_start(skb, TCA_PEDIT_KEY_EX);

  		if (!key_start)
  			goto nla_failure;

  		if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||

  		    nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd))
  			goto nla_failure;

  
  		nla_nest_end(skb, key_start);
  
  		keys_ex++;
  	}
  
  	nla_nest_end(skb, keys_start);
  
  	return 0;

  nla_failure:
  	nla_nest_cancel(skb, keys_start);
  	return -EINVAL;

  }

  static int tcf_pedit_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, pedit_net_id);

  	struct nlattr *tb[TCA_PEDIT_MAX + 1];

  	struct nlattr *pattr;

  	struct tc_pedit *parm;

  	int ret = 0, err;

  	struct tcf_pedit *p;
  	struct tc_pedit_key *keys = NULL;

  	struct tcf_pedit_key_ex *keys_ex;

  	int ksize;

  	if (nla == NULL)

  		return -EINVAL;

  	err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy, NULL);

  	if (err < 0)
  		return err;

  	pattr = tb[TCA_PEDIT_PARMS];
  	if (!pattr)
  		pattr = tb[TCA_PEDIT_PARMS_EX];
  	if (!pattr)

  		return -EINVAL;

  
  	parm = nla_data(pattr);

  	ksize = parm->nkeys * sizeof(struct tc_pedit_key);

  	if (nla_len(pattr) < sizeof(*parm) + ksize)

  		return -EINVAL;

  	keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
  	if (IS_ERR(keys_ex))
  		return PTR_ERR(keys_ex);

  	if (!tcf_idr_check(tn, parm->index, a, bind)) {

  		if (!parm->nkeys)
  			return -EINVAL;

  		ret = tcf_idr_create(tn, parm->index, est, a,
  				     &act_pedit_ops, bind, false);

  		if (ret)
  			return ret;

  		p = to_pedit(*a);

  		keys = kmalloc(ksize, GFP_KERNEL);
  		if (keys == NULL) {

  			tcf_idr_release(*a, bind);

  			kfree(keys_ex);

  			return -ENOMEM;
  		}
  		ret = ACT_P_CREATED;
  	} else {

  		if (bind)
  			return 0;

  		tcf_idr_release(*a, bind);

  		if (!ovr)

  			return -EEXIST;

  		p = to_pedit(*a);

  		if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {

  			keys = kmalloc(ksize, GFP_KERNEL);

  			if (!keys) {
  				kfree(keys_ex);

  				return -ENOMEM;

  			}

  		}
  	}

  	spin_lock_bh(&p->tcf_lock);
  	p->tcfp_flags = parm->flags;
  	p->tcf_action = parm->action;

  	if (keys) {

  		kfree(p->tcfp_keys);
  		p->tcfp_keys = keys;
  		p->tcfp_nkeys = parm->nkeys;

  	}

  	memcpy(p->tcfp_keys, parm->keys, ksize);

  
  	kfree(p->tcfp_keys_ex);
  	p->tcfp_keys_ex = keys_ex;

  	spin_unlock_bh(&p->tcf_lock);

  	if (ret == ACT_P_CREATED)

  		tcf_idr_insert(tn, *a);

  	return ret;
  }

  static void tcf_pedit_cleanup(struct tc_action *a, int bind)

  {

  	struct tcf_pedit *p = to_pedit(a);

  	struct tc_pedit_key *keys = p->tcfp_keys;
  	kfree(keys);

  	kfree(p->tcfp_keys_ex);

  }

  static bool offset_valid(struct sk_buff *skb, int offset)
  {
  	if (offset > 0 && offset > skb->len)
  		return false;
  
  	if  (offset < 0 && -offset > skb_headroom(skb))
  		return false;
  
  	return true;
  }

  static int pedit_skb_hdr_offset(struct sk_buff *skb,
  				enum pedit_header_type htype, int *hoffset)
  {
  	int ret = -EINVAL;
  
  	switch (htype) {
  	case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
  		if (skb_mac_header_was_set(skb)) {
  			*hoffset = skb_mac_offset(skb);
  			ret = 0;
  		}
  		break;
  	case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
  	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
  	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
  		*hoffset = skb_network_offset(skb);
  		ret = 0;
  		break;
  	case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
  	case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
  		if (skb_transport_header_was_set(skb)) {
  			*hoffset = skb_transport_offset(skb);
  			ret = 0;
  		}
  		break;
  	default:
  		ret = -EINVAL;
  		break;
  	};
  
  	return ret;
  }

  static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a,

  		     struct tcf_result *res)

  {

  	struct tcf_pedit *p = to_pedit(a);

  	int i;

  	if (skb_unclone(skb, GFP_ATOMIC))

  		return p->tcf_action;

  	spin_lock(&p->tcf_lock);

  	tcf_lastuse_update(&p->tcf_tm);

  	if (p->tcfp_nkeys > 0) {
  		struct tc_pedit_key *tkey = p->tcfp_keys;

  		struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
  		enum pedit_header_type htype = TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;

  		enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;

  		for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {

  			u32 *ptr, _data;

  			int offset = tkey->off;

  			int hoffset;

  			u32 val;

  			int rc;
  
  			if (tkey_ex) {
  				htype = tkey_ex->htype;

  				cmd = tkey_ex->cmd;

  				tkey_ex++;
  			}
  
  			rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
  			if (rc) {
  				pr_info("tc filter pedit bad header type specified (0x%x)
  ",
  					htype);
  				goto bad;
  			}

  
  			if (tkey->offmask) {

  				char *d, _d;

  				if (!offset_valid(skb, hoffset + tkey->at)) {

  					pr_info("tc filter pedit 'at' offset %d out of bounds
  ",

  						hoffset + tkey->at);

  					goto bad;
  				}

  				d = skb_header_pointer(skb, hoffset + tkey->at, 1,

  						       &_d);
  				if (!d)

  					goto bad;

  				offset += (*d & tkey->offmask) >> tkey->shift;

  			}
  
  			if (offset % 4) {

  				pr_info("tc filter pedit"
  					" offset must be on 32 bit boundaries
  ");

  				goto bad;
  			}

  			if (!offset_valid(skb, hoffset + offset)) {

  				pr_info("tc filter pedit offset %d out of bounds
  ",

  					hoffset + offset);

  				goto bad;
  			}

  			ptr = skb_header_pointer(skb, hoffset + offset, 4, &_data);

  			if (!ptr)
  				goto bad;

  			/* just do it, baby */

  			switch (cmd) {
  			case TCA_PEDIT_KEY_EX_CMD_SET:
  				val = tkey->val;
  				break;
  			case TCA_PEDIT_KEY_EX_CMD_ADD:
  				val = (*ptr + tkey->val) & ~tkey->mask;
  				break;
  			default:
  				pr_info("tc filter pedit bad command (%d)
  ",
  					cmd);
  				goto bad;
  			}
  
  			*ptr = ((*ptr & tkey->mask) ^ val);

  			if (ptr == &_data)

  				skb_store_bits(skb, hoffset + offset, ptr, 4);

  		}

  		goto done;

  	} else
  		WARN(1, "pedit BUG: index %d
  ", p->tcf_index);

  
  bad:

  	p->tcf_qstats.overlimits++;

  done:

  	bstats_update(&p->tcf_bstats, skb);

  	spin_unlock(&p->tcf_lock);
  	return p->tcf_action;

  }

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

  {

  	unsigned char *b = skb_tail_pointer(skb);

  	struct tcf_pedit *p = to_pedit(a);

  	struct tc_pedit *opt;

  	struct tcf_t t;

  	int s;

  	s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);

  
  	/* netlink spinlocks held above us - must use ATOMIC */

  	opt = kzalloc(s, GFP_ATOMIC);

  	if (unlikely(!opt))

  		return -ENOBUFS;

  	memcpy(opt->keys, p->tcfp_keys,
  	       p->tcfp_nkeys * sizeof(struct tc_pedit_key));
  	opt->index = p->tcf_index;
  	opt->nkeys = p->tcfp_nkeys;
  	opt->flags = p->tcfp_flags;
  	opt->action = p->tcf_action;
  	opt->refcnt = p->tcf_refcnt - ref;
  	opt->bindcnt = p->tcf_bindcnt - bind;

  	if (p->tcfp_keys_ex) {

  		if (tcf_pedit_key_ex_dump(skb,
  					  p->tcfp_keys_ex,
  					  p->tcfp_nkeys))
  			goto nla_put_failure;

  
  		if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
  			goto nla_put_failure;
  	} else {
  		if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
  			goto nla_put_failure;
  	}

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

  	if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))

  		goto nla_put_failure;

  	kfree(opt);

  	return skb->len;

  nla_put_failure:

  	nlmsg_trim(skb, b);

  	kfree(opt);

  	return -1;
  }

  static int tcf_pedit_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, pedit_net_id);

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

  }

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

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

  	return tcf_idr_search(tn, a, index);

  }

  static struct tc_action_ops act_pedit_ops = {

  	.kind		=	"pedit",
  	.type		=	TCA_ACT_PEDIT,

  	.owner		=	THIS_MODULE,
  	.act		=	tcf_pedit,
  	.dump		=	tcf_pedit_dump,
  	.cleanup	=	tcf_pedit_cleanup,

  	.init		=	tcf_pedit_init,

  	.walk		=	tcf_pedit_walker,
  	.lookup		=	tcf_pedit_search,

  	.size		=	sizeof(struct tcf_pedit),

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

  	return tc_action_net_init(tn, &act_pedit_ops);

  }
  
  static void __net_exit pedit_exit_net(struct net *net)
  {
  	struct tc_action_net *tn = net_generic(net, pedit_net_id);
  
  	tc_action_net_exit(tn);
  }
  
  static struct pernet_operations pedit_net_ops = {
  	.init = pedit_init_net,
  	.exit = pedit_exit_net,
  	.id   = &pedit_net_id,
  	.size = sizeof(struct tc_action_net),

  };
  
  MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
  MODULE_DESCRIPTION("Generic Packet Editor actions");
  MODULE_LICENSE("GPL");

  static int __init pedit_init_module(void)

  {

  	return tcf_register_action(&act_pedit_ops, &pedit_net_ops);

  }

  static void __exit pedit_cleanup_module(void)

  {

  	tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);

  }
  
  module_init(pedit_init_module);
  module_exit(pedit_cleanup_module);