ip6.h

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/*
 * ip6.h
 *
 * Internet Protocol, Version 6 (RFC 2460).
 *
 * Copyright (c) 2002 Dug Song <dugsong@monkey.org>
 *
 * $Id: ip6.h,v 1.6 2004/02/23 10:01:15 dugsong Exp $
 */

#ifndef DNET_IP6_H
#define DNET_IP6_H

#define IP6_ADDR_LEN    16
#define IP6_ADDR_BITS   128

#define IP6_HDR_LEN     40              /* IPv6 header length */
#define IP6_LEN_MIN     IP6_HDR_LEN
#define IP6_LEN_MAX     65535           /* non-jumbo payload */

#define IP6_MTU_MIN     1280            /* minimum MTU (1024 + 256) */

typedef struct ip6_addr {
        uint8_t         data[IP6_ADDR_LEN];
} ip6_addr_t;

#ifndef __GNUC__
# define __attribute__(x)
# pragma pack(1)
#endif

/*
 * IPv6 header
 */
struct ip6_hdr {
        union {
                struct ip6_hdr_ctl {
                        uint32_t        ip6_un1_flow; /* 20 bits of flow ID */
                        uint16_t        ip6_un1_plen; /* payload length */
                        uint8_t         ip6_un1_nxt;  /* next header */
                        uint8_t         ip6_un1_hlim; /* hop limit */
                } ip6_un1;
                uint8_t ip6_un2_vfc;    /* 4 bits version, top 4 bits class */
        } ip6_ctlun;
        ip6_addr_t      ip6_src;
        ip6_addr_t      ip6_dst;
} __attribute__((__packed__));

#define ip6_vfc         ip6_ctlun.ip6_un2_vfc
#define ip6_flow        ip6_ctlun.ip6_un1.ip6_un1_flow
#define ip6_plen        ip6_ctlun.ip6_un1.ip6_un1_plen
#define ip6_nxt         ip6_ctlun.ip6_un1.ip6_un1_nxt   /* IP_PROTO_* */
#define ip6_hlim        ip6_ctlun.ip6_un1.ip6_un1_hlim

#define IP6_VERSION             0x60
#define IP6_VERSION_MASK        0xf0            /* ip6_vfc version */

#if DNET_BYTESEX == DNET_BIG_ENDIAN
#define IP6_FLOWINFO_MASK       0x0fffffff      /* ip6_flow info (28 bits) */
#define IP6_FLOWLABEL_MASK      0x000fffff      /* ip6_flow label (20 bits) */
#elif DNET_BYTESEX == DNET_LIL_ENDIAN
#define IP6_FLOWINFO_MASK       0xffffff0f      /* ip6_flow info (28 bits) */
#define IP6_FLOWLABEL_MASK      0xffff0f00      /* ip6_flow label (20 bits) */
#endif

/*
 * Hop limit (ip6_hlim)
 */
#define IP6_HLIM_DEFAULT        64
#define IP6_HLIM_MAX            255

/*
 * Preferred extension header order from RFC 2460, 4.1:
 *
 * IP_PROTO_IPV6, IP_PROTO_HOPOPTS, IP_PROTO_DSTOPTS, IP_PROTO_ROUTING,
 * IP_PROTO_FRAGMENT, IP_PROTO_AH, IP_PROTO_ESP, IP_PROTO_DSTOPTS, IP_PROTO_*
 */

/*
 * Routing header data (IP_PROTO_ROUTING)
 */
struct ip6_ext_data_routing {
        uint8_t  type;                  /* routing type */
        uint8_t  segleft;               /* segments left */
        /* followed by routing type specific data */
} __attribute__((__packed__));

struct ip6_ext_data_routing0 {
        uint8_t  type;                  /* always zero */
        uint8_t  segleft;               /* segments left */
        uint8_t  reserved;              /* reserved field */
        uint8_t  slmap[3];              /* strict/loose bit map */
        ip6_addr_t  addr[1];            /* up to 23 addresses */
} __attribute__((__packed__));

/*
 * Fragment header data (IP_PROTO_FRAGMENT)
 */
struct ip6_ext_data_fragment {
        uint16_t  offlg;                /* offset, reserved, and flag */
        uint32_t  ident;                /* identification */
} __attribute__((__packed__));

/*
 * Fragmentation offset, reserved, and flags (offlg)
 */
#if DNET_BYTESEX == DNET_BIG_ENDIAN
#define IP6_OFF_MASK            0xfff8  /* mask out offset from offlg */
#define IP6_RESERVED_MASK       0x0006  /* reserved bits in offlg */
#define IP6_MORE_FRAG           0x0001  /* more-fragments flag */
#elif DNET_BYTESEX == DNET_LIL_ENDIAN
#define IP6_OFF_MASK            0xf8ff  /* mask out offset from offlg */
#define IP6_RESERVED_MASK       0x0600  /* reserved bits in offlg */
#define IP6_MORE_FRAG           0x0100  /* more-fragments flag */
#endif

/*
 * Option types, for IP_PROTO_HOPOPTS, IP_PROTO_DSTOPTS headers
 */
#define IP6_OPT_PAD1            0x00    /* 00 0 00000 */
#define IP6_OPT_PADN            0x01    /* 00 0 00001 */
#define IP6_OPT_JUMBO           0xC2    /* 11 0 00010 = 194 */
#define IP6_OPT_JUMBO_LEN       6
#define IP6_OPT_RTALERT         0x05    /* 00 0 00101 */
#define IP6_OPT_RTALERT_LEN     4
#define IP6_OPT_RTALERT_MLD     0       /* Datagram contains an MLD message */
#define IP6_OPT_RTALERT_RSVP    1       /* Datagram contains an RSVP message */
#define IP6_OPT_RTALERT_ACTNET  2       /* contains an Active Networks msg */
#define IP6_OPT_LEN_MIN         2

#define IP6_OPT_TYPE(o)         ((o) & 0xC0)    /* high 2 bits of opt_type */
#define IP6_OPT_TYPE_SKIP       0x00    /* continue processing on failure */
#define IP6_OPT_TYPE_DISCARD    0x40    /* discard packet on failure */
#define IP6_OPT_TYPE_FORCEICMP  0x80    /* discard and send ICMP on failure */
#define IP6_OPT_TYPE_ICMP       0xC0    /* ...only if non-multicast dst */

#define IP6_OPT_MUTABLE         0x20    /* option data may change en route */

/*
 * Extension header (chained via {ip6,ext}_nxt, following IPv6 header)
 */
struct ip6_ext_hdr {
        uint8_t  ext_nxt;       /* next header */
        uint8_t  ext_len;       /* following length in units of 8 octets */
        union {
                struct ip6_ext_data_routing     routing;
                struct ip6_ext_data_fragment    fragment;
        } ext_data;
} __attribute__((__packed__));

#ifndef __GNUC__
# pragma pack()
#endif

/*
 * Reserved addresses
 */
#define IP6_ADDR_UNSPEC \
        "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
#define IP6_ADDR_LOOPBACK \
        "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01"

#define ip6_pack_hdr(hdr, fc, fl, plen, nxt, hlim, src, dst) do {       \
        struct ip6_hdr *ip6 = (struct ip6_hdr *)(hdr);                  \
        ip6->ip6_flow = htonl(((uint32_t)(fc) << 28) &                  \
            (IP6_FLOWLABEL_MASK | (fl)));                               \
        ip6->ip6_vfc = (IP6_VERSION | ((fc) >> 4));                     \
        ip6->ip6_plen = htons((plen));                                  \
        ip6->ip6_nxt = (nxt); ip6->ip6_hlim = (hlim);                   \
        memmove(&ip6->ip6_src, &(src), IP6_ADDR_LEN);                   \
        memmove(&ip6->ip6_dst, &(dst), IP6_ADDR_LEN);                   \
} while (0);

__BEGIN_DECLS
char    *ip6_ntop(const ip6_addr_t *ip6, char *dst, size_t size);
int      ip6_pton(const char *src, ip6_addr_t *dst);
char    *ip6_ntoa(const ip6_addr_t *ip6);
#define  ip6_aton ip6_pton

void     ip6_checksum(void *buf, size_t len);
__END_DECLS

#endif /* DNET_IP6_H */

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