// SPDX-License-Identifier: GPL-2.0

  /*
   * xfrm4_state.c
   *
   * Changes:
   * 	YOSHIFUJI Hideaki @USAGI
   * 		Split up af-specific portion
   *
   */

  #include <net/ip.h>

  #include <net/xfrm.h>
  #include <linux/pfkeyv2.h>
  #include <linux/ipsec.h>

  #include <linux/netfilter_ipv4.h>

  #include <linux/export.h>

  static int xfrm4_init_flags(struct xfrm_state *x)
  {

  	if (xs_net(x)->ipv4.sysctl_ip_no_pmtu_disc)

  		x->props.flags |= XFRM_STATE_NOPMTUDISC;
  	return 0;
  }

  static void

  __xfrm4_init_tempsel(struct xfrm_selector *sel, const struct flowi *fl)

  {

  	const struct flowi4 *fl4 = &fl->u.ip4;
  
  	sel->daddr.a4 = fl4->daddr;
  	sel->saddr.a4 = fl4->saddr;
  	sel->dport = xfrm_flowi_dport(fl, &fl4->uli);

  	sel->dport_mask = htons(0xffff);

  	sel->sport = xfrm_flowi_sport(fl, &fl4->uli);

  	sel->sport_mask = htons(0xffff);
  	sel->family = AF_INET;
  	sel->prefixlen_d = 32;
  	sel->prefixlen_s = 32;

  	sel->proto = fl4->flowi4_proto;
  	sel->ifindex = fl4->flowi4_oif;

  }
  
  static void

  xfrm4_init_temprop(struct xfrm_state *x, const struct xfrm_tmpl *tmpl,
  		   const xfrm_address_t *daddr, const xfrm_address_t *saddr)

  {

  	x->id = tmpl->id;
  	if (x->id.daddr.a4 == 0)
  		x->id.daddr.a4 = daddr->a4;
  	x->props.saddr = tmpl->saddr;
  	if (x->props.saddr.a4 == 0)
  		x->props.saddr.a4 = saddr->a4;
  	x->props.mode = tmpl->mode;
  	x->props.reqid = tmpl->reqid;
  	x->props.family = AF_INET;
  }

  int xfrm4_extract_header(struct sk_buff *skb)
  {

  	const struct iphdr *iph = ip_hdr(skb);

  	XFRM_MODE_SKB_CB(skb)->ihl = sizeof(*iph);

  	XFRM_MODE_SKB_CB(skb)->id = iph->id;
  	XFRM_MODE_SKB_CB(skb)->frag_off = iph->frag_off;
  	XFRM_MODE_SKB_CB(skb)->tos = iph->tos;
  	XFRM_MODE_SKB_CB(skb)->ttl = iph->ttl;

  	XFRM_MODE_SKB_CB(skb)->optlen = iph->ihl * 4 - sizeof(*iph);

  	memset(XFRM_MODE_SKB_CB(skb)->flow_lbl, 0,
  	       sizeof(XFRM_MODE_SKB_CB(skb)->flow_lbl));
  
  	return 0;
  }

  static struct xfrm_state_afinfo xfrm4_state_afinfo = {
  	.family			= AF_INET,

  	.proto			= IPPROTO_IPIP,

  	.eth_proto		= htons(ETH_P_IP),

  	.owner			= THIS_MODULE,

  	.init_flags		= xfrm4_init_flags,

  	.init_tempsel		= __xfrm4_init_tempsel,

  	.init_temprop		= xfrm4_init_temprop,

  	.output			= xfrm4_output,

  	.output_finish		= xfrm4_output_finish,

  	.extract_input		= xfrm4_extract_input,

  	.extract_output		= xfrm4_extract_output,

  	.transport_finish	= xfrm4_transport_finish,

  	.local_error		= xfrm4_local_error,

  };
  
  void __init xfrm4_state_init(void)
  {
  	xfrm_state_register_afinfo(&xfrm4_state_afinfo);
  }