/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/ipv6.h>
#include <net/dsfield.h>
#include <net/xfrm.h>

#ifndef XFRM_INOUT_H
#define XFRM_INOUT_H 1

static inline void 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));
}

static inline void xfrm6_extract_header(struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_IPV6)
        struct ipv6hdr *iph = ipv6_hdr(skb);

        XFRM_MODE_SKB_CB(skb)->ihl = sizeof(*iph);
        XFRM_MODE_SKB_CB(skb)->id = 0;
        XFRM_MODE_SKB_CB(skb)->frag_off = htons(IP_DF);
        XFRM_MODE_SKB_CB(skb)->tos = ipv6_get_dsfield(iph);
        XFRM_MODE_SKB_CB(skb)->ttl = iph->hop_limit;
        XFRM_MODE_SKB_CB(skb)->optlen = 0;
        memcpy(XFRM_MODE_SKB_CB(skb)->flow_lbl, iph->flow_lbl,
               sizeof(XFRM_MODE_SKB_CB(skb)->flow_lbl));
#else
        WARN_ON_ONCE(1);
#endif
}

static inline void xfrm6_beet_make_header(struct sk_buff *skb)
{
        struct ipv6hdr *iph = ipv6_hdr(skb);

        iph->version = 6;

        memcpy(iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
               sizeof(iph->flow_lbl));
        iph->nexthdr = XFRM_MODE_SKB_CB(skb)->protocol;

        ipv6_change_dsfield(iph, 0, XFRM_MODE_SKB_CB(skb)->tos);
        iph->hop_limit = XFRM_MODE_SKB_CB(skb)->ttl;
}

static inline void xfrm4_beet_make_header(struct sk_buff *skb)
{
        struct iphdr *iph = ip_hdr(skb);

        iph->ihl = 5;
        iph->version = 4;

        iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
        iph->tos = XFRM_MODE_SKB_CB(skb)->tos;

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

#endif