n2n_wire.h

/* (c) 2009 Richard Andrews <andrews@ntop.org> 
 *
 * Contributions by:
 *    Luca Deri
 *    Lukasz Taczuk
 */

#if !defined( N2N_WIRE_H_ )
#define N2N_WIRE_H_

#include <stdlib.h>

#if defined(WIN32)
#include "win32/n2n_win32.h"

#if defined(__MINGW32__)
#include <stdint.h>
#endif /* #ifdef __MINGW32__ */

#else /* #if defined(WIN32) */
#include <stdint.h>
#include <netinet/in.h>
#include <sys/socket.h> /* AF_INET and AF_INET6 */
#endif /* #if defined(WIN32) */


#include "n2n_net.h"



#define N2N_PKT_VERSION                 2
#define N2N_DEFAULT_TTL                 2       /* can be forwarded twice at most */
#define N2N_PKT_BUF_SIZE                2048
#define N2N_COMMUNITY_SIZE              16
#define N2N_SOCKBUF_SIZE                64      /* string representation of INET or INET6 sockets */
#define N2N_COOKIE_SIZE                 4

typedef uint8_t n2n_community_t[N2N_COMMUNITY_SIZE];
typedef uint8_t n2n_cookie_t[N2N_COOKIE_SIZE];


/**
 * Message types
 */
enum n2n_pc
{
    n2n_ping=0,                 /* Not used */
    n2n_register=1,             /* Register edge to edge */
    n2n_deregister=2,           /* Deregister this edge */
    n2n_packet=3,               /* PACKET data content */
    n2n_register_ack=4,         /* ACK of a registration from edge to edge */
    n2n_register_super=5,       /* Register edge to supernode */
    n2n_register_super_ack=6,   /* ACK from supernode to edge */
    n2n_register_super_nak=7,   /* NAK from supernode to edge - registration refused */
    n2n_federation=8            /* Not used by edge */

#ifdef N2N_MULTIPLE_SUPERNODES
    , /* because of -pedantic */
    n2n_query_super = 9,
    n2n_query_super_ack = 10,
#endif
};

typedef enum n2n_pc n2n_pc_t;

/**
 * Flags
 */
#define N2N_FLAGS_OPTIONS               0x0080
#define N2N_FLAGS_SOCKET                0x0040
#define N2N_FLAGS_FROM_SUPERNODE        0x0020

/* The bits in flag that are the packet type */
#define N2N_FLAGS_TYPE_MASK             0x001f  /* 0 - 31 */
#define N2N_FLAGS_BITS_MASK             0xffe0

/* The bits in flag that are used in federation */

/* | | |A|S| */
#define N2N_FLAGS_FED_SUBSCRIBE         0x1000
#define N2N_FLAGS_FED_ACK               0x2000
#define N2N_FLAGS_FED_C                 0x4000


#define N2N_AUTH_TOKEN_SIZE             32      /* bytes */


#define N2N_EUNKNOWN                    -1
#define N2N_ENOTIMPL                    -2
#define N2N_EINVAL                      -3
#define N2N_ENOSPACE                    -4


typedef uint16_t n2n_flags_t;
typedef uint16_t n2n_transform_t;       /* Encryption, compression type. */
typedef uint32_t n2n_sa_t;              /* security association number */



struct n2n_auth
{
    uint16_t    scheme;                         /* What kind of auth */
    uint16_t    toksize;                        /* Size of auth token */
    uint8_t     token[N2N_AUTH_TOKEN_SIZE];     /* Auth data interpreted based on scheme */
};

typedef struct n2n_auth n2n_auth_t;


/******************************************************************************
 *
 * MESSAGES STRUCTURES
 *
 */

struct n2n_common
{
    /* int                 version; */
    uint8_t             ttl;
    n2n_pc_t            pc;
    n2n_flags_t         flags;
    n2n_community_t     community;
};

typedef struct n2n_common n2n_common_t;


struct n2n_REGISTER
{
    n2n_cookie_t        cookie;         /* Link REGISTER and REGISTER_ACK */
    n2n_mac_t           srcMac;         /* MAC of registering party */
    n2n_mac_t           dstMac;         /* MAC of target edge */
    n2n_sock_t          sock;           /* REVISIT: unused? */
};

typedef struct n2n_REGISTER n2n_REGISTER_t;


struct n2n_REGISTER_ACK
{
    n2n_cookie_t        cookie;         /* Return cookie from REGISTER */
    n2n_mac_t           srcMac;         /* MAC of acknowledging party (supernode or edge) */
    n2n_mac_t           dstMac;         /* Reflected MAC of registering edge from REGISTER */
    n2n_sock_t          sock;           /* Supernode's view of edge socket (IP Addr, port) */
};

typedef struct n2n_REGISTER_ACK n2n_REGISTER_ACK_t;


struct n2n_PACKET
{
    n2n_mac_t           srcMac;
    n2n_mac_t           dstMac;
    n2n_sock_t          sock;
    n2n_transform_t     transform;
};

typedef struct n2n_PACKET n2n_PACKET_t;


/* Linked with n2n_register_super in n2n_pc_t. Only from edge to supernode. */
struct n2n_REGISTER_SUPER
{
    n2n_cookie_t        cookie;         /* Link REGISTER_SUPER and REGISTER_SUPER_ACK */
    n2n_mac_t           edgeMac;        /* MAC to register with edge sending socket */
    n2n_auth_t          auth;           /* Authentication scheme and tokens */
};

typedef struct n2n_REGISTER_SUPER n2n_REGISTER_SUPER_t;


/* Linked with n2n_register_super_ack in n2n_pc_t. Only from supernode to edge. */
struct n2n_REGISTER_SUPER_ACK
{
    n2n_cookie_t        cookie;         /* Return cookie from REGISTER_SUPER */
    n2n_mac_t           edgeMac;        /* MAC registered to edge sending socket */
    uint16_t            lifetime;       /* How long the registration will live */
    n2n_sock_t          sock;           /* Sending sockets associated with edgeMac */

    /* The packet format provides additional supernode definitions here. 
     * uint8_t count, then for each count there is one
     * n2n_sock_t.
     */
    uint8_t             num_sn;         /* Number of supernodes that were send
                                         * even if we cannot store them all. If
                                         * non-zero then sn_bak is valid. */

#ifdef N2N_MULTIPLE_SUPERNODES
    n2n_sock_t          sn_bak[4];
#else
    n2n_sock_t          sn_bak;         /* Socket of the first backup supernode */
#endif

};

typedef struct n2n_REGISTER_SUPER_ACK n2n_REGISTER_SUPER_ACK_t;


/* Linked with n2n_register_super_ack in n2n_pc_t. Only from supernode to edge. */
struct n2n_REGISTER_SUPER_NAK
{
    n2n_cookie_t        cookie;         /* Return cookie from REGISTER_SUPER */
};

typedef struct n2n_REGISTER_SUPER_NAK n2n_REGISTER_SUPER_NAK_t;


#ifdef N2N_MULTIPLE_SUPERNODES

struct n2n_FEDERATION
{
    uint16_t            edges_num;
};

//TODO flags: keepalive, someones dead

typedef struct n2n_FEDERATION n2n_FEDERATION_t;


struct n2n_QUERY_SUPER
{
    n2n_cookie_t        cookie;         /* Link QUERY_SUPER and QUERY_SUPER_ACK */
};

typedef struct n2n_QUERY_SUPER n2n_QUERY_SUPER_t;


struct n2n_QUERY_SUPER_ACK
{
    n2n_cookie_t        cookie;         /* Link QUERY_SUPER and QUERY_SUPER_ACK */
    uint8_t             num_sn;         /* Number of supernodes that were send
                                         * even if we cannot store them all. If
                                         * non-zero then members is valid. */
    n2n_sock_t          members[4];//TODO number
};

typedef struct n2n_QUERY_SUPER_ACK n2n_QUERY_SUPER_ACK_t;

#endif /* #ifdef N2N_MULTIPLE_SUPERNODES */


struct n2n_buf
{
    uint8_t       *data;
    size_t         size;
};

typedef struct n2n_buf n2n_buf_t;



/******************************************************************************
 *
 * ENCODING/DECODING FUNCTIONS
 *
 */

/**
 * Utils
 */

int encode_uint8(uint8_t *base,
                 size_t *idx,
                 const uint8_t v);

int decode_uint8(uint8_t *out,
                 const uint8_t *base,
                 size_t *rem,
                 size_t *idx);

int encode_uint16(uint8_t *base,
                  size_t *idx,
                  const uint16_t v);

int decode_uint16(uint16_t *out,
                  const uint8_t *base,
                  size_t *rem,
                  size_t *idx);

int encode_uint32(uint8_t *base,
                  size_t *idx,
                  const uint32_t v);

int decode_uint32(uint32_t *out,
                  const uint8_t *base,
                  size_t *rem,
                  size_t *idx);

int encode_buf(uint8_t *base,
               size_t *idx,
               const void *p,
               size_t s);

int decode_buf(uint8_t *out,
               size_t bufsize,
               const uint8_t *base,
               size_t *rem,
               size_t *idx);

int encode_mac(uint8_t *base,
               size_t *idx,
               const n2n_mac_t m);

int decode_mac(uint8_t *out, /* of size N2N_MAC_SIZE. This clearer than passing a n2n_mac_t */
               const uint8_t *base,
               size_t *rem,
               size_t *idx);

int encode_sock(uint8_t *base,
                size_t *idx,
                const n2n_sock_t *sock);

int decode_sock(n2n_sock_t *sock,
                const uint8_t *base,
                size_t *rem,
                size_t *idx);

/**
 * Message encoding/decoding
 */

int encode_common(uint8_t *base,
                  size_t *idx,
                  const n2n_common_t *common);

int decode_common(n2n_common_t *out,
                  const uint8_t *base,
                  size_t *rem,
                  size_t *idx);

int encode_REGISTER(uint8_t *base,
                    size_t *idx,
                    const n2n_common_t *common,
                    const n2n_REGISTER_t *reg);

int decode_REGISTER(n2n_REGISTER_t *pkt,
                    const n2n_common_t *cmn, /* info on how to interpret it */
                    const uint8_t *base,
                    size_t *rem,
                    size_t *idx);

int encode_REGISTER_SUPER(uint8_t *base,
                          size_t *idx,
                          const n2n_common_t *common,
                          const n2n_REGISTER_SUPER_t *reg);

int decode_REGISTER_SUPER(n2n_REGISTER_SUPER_t *pkt,
                          const n2n_common_t *cmn, /* info on how to interpret it */
                          const uint8_t *base,
                          size_t *rem,
                          size_t *idx);

int encode_REGISTER_ACK(uint8_t *base,
                        size_t *idx,
                        const n2n_common_t *common,
                        const n2n_REGISTER_ACK_t *reg);

int decode_REGISTER_ACK(n2n_REGISTER_ACK_t *pkt,
                        const n2n_common_t *cmn, /* info on how to interpret it */
                        const uint8_t *base,
                        size_t *rem,
                        size_t *idx);

int encode_REGISTER_SUPER_ACK(uint8_t *base,
                              size_t *idx,
                              const n2n_common_t *cmn,
                              const n2n_REGISTER_SUPER_ACK_t *reg);

int decode_REGISTER_SUPER_ACK(n2n_REGISTER_SUPER_ACK_t *reg,
                              const n2n_common_t *cmn, /* info on how to interpret it */
                              const uint8_t *base,
                              size_t *rem,
                              size_t *idx);


#ifdef N2N_MULTIPLE_SUPERNODES

int encode_FEDERATION(uint8_t *base,
                      size_t *idx,
                      const n2n_common_t *cmn,
                      const n2n_FEDERATION_t *fed);

int decode_FEDERATION(n2n_FEDERATION_t *fed,
                      const n2n_common_t *cmn, /* info on how to interpret it */
                      const uint8_t *base,
                      size_t *rem,
                      size_t *idx);

int encode_QUERY_SUPER(uint8_t *base,
                       size_t *idx,
                       const n2n_common_t *cmn,
                       const n2n_QUERY_SUPER_t *q);

int decode_QUERY_SUPER(n2n_QUERY_SUPER_t *q,
                       const n2n_common_t *cmn, /* info on how to interpret it */
                       const uint8_t *base,
                       size_t *rem,
                       size_t *idx);

int encode_QUERY_SUPER_ACK(uint8_t *base,
                           size_t *idx,
                           const n2n_common_t *cmn,
                           const n2n_QUERY_SUPER_ACK_t *qack);

int decode_QUERY_SUPER_ACK(n2n_QUERY_SUPER_ACK_t *qack,
                           const n2n_common_t *cmn, /* info on how to interpret it */
                           const uint8_t *base,
                           size_t *rem,
                           size_t *idx);

#endif /* #ifdef N2N_MULTIPLE_SUPERNODES */


int encode_PACKET(uint8_t *base,
                  size_t *idx,
                  const n2n_common_t *common,
                  const n2n_PACKET_t *pkt);

int decode_PACKET(n2n_PACKET_t *pkt,
                  const n2n_common_t *cmn, /* info on how to interpret it */
                  const uint8_t *base,
                  size_t *rem,
                  size_t *idx);

/**
 * Helper function for initializing n2n_common_t structures.
 */

void init_cmn(n2n_common_t *cmn,
              n2n_pc_t pc,
              n2n_flags_t flags,
              const n2n_community_t community);


#endif /* #if !defined( N2N_WIRE_H_ ) */