/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * INET         An implementation of the TCP/IP protocol suite for the LINUX
 *              operating system.  INET is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              Definitions for the protocol dispatcher.
 *
 * Version:     @(#)protocol.h  1.0.2   05/07/93
 *
 * Author:      Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *
 *      Changes:
 *              Alan Cox        :       Added a name field and a frag handler
 *                                      field for later.
 *              Alan Cox        :       Cleaned up, and sorted types.
 *              Pedro Roque     :       inet6 protocols
 */
 
#ifndef _PROTOCOL_H
#define _PROTOCOL_H

#include <linux/in6.h>
#include <linux/skbuff.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <linux/ipv6.h>
#endif
#include <linux/netdevice.h>

/* This is one larger than the largest protocol value that can be
 * found in an ipv4 or ipv6 header.  Since in both cases the protocol
 * value is presented in a __u8, this is defined to be 256.
 */
#define MAX_INET_PROTOS         256

/* This is used to register protocols. */
struct net_protocol {
        int                     (*handler)(struct sk_buff *skb);

        /* This returns an error if we weren't able to handle the error. */
        int                     (*err_handler)(struct sk_buff *skb, u32 info);

        unsigned int            no_policy:1,
                                /* does the protocol do more stringent
                                 * icmp tag validation than simple
                                 * socket lookup?
                                 */
                                icmp_strict_tag_validation:1;
        u32                     secret;
};

#if IS_ENABLED(CONFIG_IPV6)
struct inet6_protocol {
        int     (*handler)(struct sk_buff *skb);

        /* This returns an error if we weren't able to handle the error. */
        int     (*err_handler)(struct sk_buff *skb,
                               struct inet6_skb_parm *opt,
                               u8 type, u8 code, int offset,
                               __be32 info);

        unsigned int    flags;  /* INET6_PROTO_xxx */
        u32             secret;
};

#define INET6_PROTO_NOPOLICY    0x1
#define INET6_PROTO_FINAL       0x2
#endif

struct net_offload {
        struct offload_callbacks callbacks;
        unsigned int             flags; /* Flags used by IPv6 for now */
        u32                      secret;
};
/* This should be set for any extension header which is compatible with GSO. */
#define INET6_PROTO_GSO_EXTHDR  0x1

/* This is used to register socket interfaces for IP protocols.  */
struct inet_protosw {
        struct list_head list;

        /* These two fields form the lookup key.  */
        unsigned short   type;     /* This is the 2nd argument to socket(2). */
        unsigned short   protocol; /* This is the L4 protocol number.  */

        struct proto     *prot;
        const struct proto_ops *ops;
  
        unsigned char    flags;      /* See INET_PROTOSW_* below.  */
};
#define INET_PROTOSW_REUSE 0x01      /* Are ports automatically reusable? */
#define INET_PROTOSW_PERMANENT 0x02  /* Permanent protocols are unremovable. */
#define INET_PROTOSW_ICSK      0x04  /* Is this an inet_connection_sock? */

extern struct net_protocol __rcu *inet_protos[MAX_INET_PROTOS];
extern const struct net_offload __rcu *inet_offloads[MAX_INET_PROTOS];
extern const struct net_offload __rcu *inet6_offloads[MAX_INET_PROTOS];

#if IS_ENABLED(CONFIG_IPV6)
extern struct inet6_protocol __rcu *inet6_protos[MAX_INET_PROTOS];
#endif

int inet_add_protocol(const struct net_protocol *prot, unsigned char num);
int inet_del_protocol(const struct net_protocol *prot, unsigned char num);
int inet_add_offload(const struct net_offload *prot, unsigned char num);
int inet_del_offload(const struct net_offload *prot, unsigned char num);
void inet_register_protosw(struct inet_protosw *p);
void inet_unregister_protosw(struct inet_protosw *p);

#if IS_ENABLED(CONFIG_IPV6)
int inet6_add_protocol(const struct inet6_protocol *prot, unsigned char num);
int inet6_del_protocol(const struct inet6_protocol *prot, unsigned char num);
int inet6_register_protosw(struct inet_protosw *p);
void inet6_unregister_protosw(struct inet_protosw *p);
#endif
int inet6_add_offload(const struct net_offload *prot, unsigned char num);
int inet6_del_offload(const struct net_offload *prot, unsigned char num);

#endif  /* _PROTOCOL_H */