/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _PFCP_H_
#define _PFCP_H_

#include <uapi/linux/if_ether.h>
#include <net/dst_metadata.h>
#include <linux/netdevice.h>
#include <uapi/linux/ipv6.h>
#include <net/udp_tunnel.h>
#include <uapi/linux/udp.h>
#include <uapi/linux/ip.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/bits.h>

#define PFCP_PORT 8805

/* PFCP protocol header */
struct pfcphdr {
        u8      flags;
        u8      message_type;
        __be16  message_length;
};

/* PFCP header flags */
#define PFCP_SEID_FLAG          BIT(0)
#define PFCP_MP_FLAG            BIT(1)

#define PFCP_VERSION_MASK       GENMASK(4, 0)

#define PFCP_HLEN (sizeof(struct udphdr) + sizeof(struct pfcphdr))

/* PFCP node related messages */
struct pfcphdr_node {
        u8      seq_number[3];
        u8      reserved;
};

/* PFCP session related messages */
struct pfcphdr_session {
        __be64  seid;
        u8      seq_number[3];
#ifdef __LITTLE_ENDIAN_BITFIELD
        u8      message_priority:4,
                reserved:4;
#elif defined(__BIG_ENDIAN_BITFIELD)
        u8      reserved:4,
                message_priority:4;
#else
#error "Please fix <asm/byteorder>"
#endif
};

struct pfcp_metadata {
        u8 type;
        __be64 seid;
} __packed;

enum {
        PFCP_TYPE_NODE          = 0,
        PFCP_TYPE_SESSION       = 1,
};

#define PFCP_HEADROOM (sizeof(struct iphdr) + sizeof(struct udphdr) + \
                       sizeof(struct pfcphdr) + sizeof(struct ethhdr))
#define PFCP6_HEADROOM (sizeof(struct ipv6hdr) + sizeof(struct udphdr) + \
                        sizeof(struct pfcphdr) + sizeof(struct ethhdr))

static inline struct pfcphdr *pfcp_hdr(struct sk_buff *skb)
{
        return (struct pfcphdr *)(udp_hdr(skb) + 1);
}

static inline struct pfcphdr_node *pfcp_hdr_node(struct sk_buff *skb)
{
        return (struct pfcphdr_node *)(pfcp_hdr(skb) + 1);
}

static inline struct pfcphdr_session *pfcp_hdr_session(struct sk_buff *skb)
{
        return (struct pfcphdr_session *)(pfcp_hdr(skb) + 1);
}

static inline bool netif_is_pfcp(const struct net_device *dev)
{
        return dev->rtnl_link_ops &&
               !strcmp(dev->rtnl_link_ops->kind, "pfcp");
}

#endif