bird/lib/ip.h

/*
 *	BIRD Internet Routing Daemon -- The Internet Protocol
 *
 *	(c) 1998 Martin Mares <mj@ucw.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

#ifndef _BIRD_IP_H_
#define _BIRD_IP_H_

#include "lib/endian.h"
#include "lib/string.h"
#include "lib/bitops.h"
#include "lib/unaligned.h"


#define IP4_ALL_NODES		ipa_build4(224, 0, 0, 1)
#define IP4_ALL_ROUTERS		ipa_build4(224, 0, 0, 2)
#define IP4_OSPF_ALL_ROUTERS	ipa_build4(224, 0, 0, 5)
#define IP4_OSPF_DES_ROUTERS	ipa_build4(224, 0, 0, 6)
#define IP4_RIP_ROUTERS		ipa_build4(224, 0, 0, 9)

#define IP6_ALL_NODES		ipa_build6(0xFF020000, 0, 0, 1)
#define IP6_ALL_ROUTERS		ipa_build6(0xFF020000, 0, 0, 2)
#define IP6_OSPF_ALL_ROUTERS	ipa_build6(0xFF020000, 0, 0, 5)
#define IP6_OSPF_DES_ROUTERS	ipa_build6(0xFF020000, 0, 0, 6)
#define IP6_RIP_ROUTERS		ipa_build6(0xFF020000, 0, 0, 9)

#define IP4_NONE		_MI4(0)
#define IP6_NONE		_MI6(0,0,0,0)

#define IP4_MIN_MTU		576
#define IP6_MIN_MTU		1280

#define IP_PREC_INTERNET_CONTROL 0xc0

#define IP4_HEADER_LENGTH	20
#define IP6_HEADER_LENGTH	40
#define UDP_HEADER_LENGTH	8


#ifdef IPV6
#define MAX_PREFIX_LENGTH 128
#define BITS_PER_IP_ADDRESS 128
#define STD_ADDRESS_P_LENGTH 39
#define SIZE_OF_IP_HEADER 40
#else
#define MAX_PREFIX_LENGTH 32
#define BITS_PER_IP_ADDRESS 32
#define STD_ADDRESS_P_LENGTH 15
#define SIZE_OF_IP_HEADER 24
#endif


#ifdef DEBUGGING

typedef struct ip4_addr {
  u32 addr;
} ip4_addr;

#define _MI4(x) ((struct ip4_addr) { x })
#define _I(x) (x).addr

#else

typedef u32 ip4_addr;

#define _MI4(x) (x)
#define _I(x) (x)

#endif


typedef struct ip6_addr {
  u32 addr[4];
} ip6_addr;

#define _MI6(a,b,c,d) ((struct ip6_addr) {{ a, b, c, d }})
#define _I0(a) ((a).addr[0])
#define _I1(a) ((a).addr[1])
#define _I2(a) ((a).addr[2])
#define _I3(a) ((a).addr[3])


#ifdef IPV6

/* Structure ip_addr may contain both IPv4 and IPv6 addresses */
typedef ip6_addr ip_addr;
#define IPA_NONE IP6_NONE

#define ipa_from_ip4(x) _MI6(0,0,0xffff,_I(x))
#define ipa_from_ip6(x) x
#define ipa_from_u32(x) ipa_from_ip4(ip4_from_u32(x))

#define ipa_to_ip4(x) _MI4(_I3(x))
#define ipa_to_ip6(x) x
#define ipa_to_u32(x) ip4_to_u32(ipa_to_ip4(x))

#define ipa_is_ip4(a) ip6_is_v4mapped(a)

#else

/* Provisionary ip_addr definition same as ip4_addr */
typedef ip4_addr ip_addr;
#define IPA_NONE IP4_NONE

#define ipa_from_ip4(x) x
#define ipa_from_ip6(x) IPA_NONE
#define ipa_from_u32(x) ipa_from_ip4(ip4_from_u32(x))

#define ipa_to_ip4(x) x
#define ipa_to_ip6(x) IP6_NONE
#define ipa_to_u32(x) ip4_to_u32(ipa_to_ip4(x))

#define ipa_is_ip4(a) 1

#endif


/*
 *	Public constructors
 */

#define ip4_from_u32(x) _MI4(x)
#define ip4_to_u32(x) _I(x)

#define ip4_build(a,b,c,d) _MI4(((a) << 24) | ((b) << 16) | ((c) << 8) | (d))
#define ip6_build(a,b,c,d) _MI6(a,b,c,d)

#define ipa_build4(a,b,c,d) ipa_from_ip4(ip4_build(a,b,c,d))
#define ipa_build6(a,b,c,d) ipa_from_ip6(ip6_build(a,b,c,d))


/*
 *	Basic algebraic functions
 */

static inline int ip4_equal(ip4_addr a, ip4_addr b)
{ return _I(a) == _I(b); }

static inline int ip4_zero(ip4_addr a)
{ return _I(a) == 0; }

static inline int ip4_nonzero(ip4_addr a)
{ return _I(a) != 0; }

static inline ip4_addr ip4_and(ip4_addr a, ip4_addr b)
{ return _MI4(_I(a) & _I(b)); }

static inline ip4_addr ip4_or(ip4_addr a, ip4_addr b)
{ return _MI4(_I(a) | _I(b)); }

static inline ip4_addr ip4_xor(ip4_addr a, ip4_addr b)
{ return _MI4(_I(a) ^ _I(b)); }

static inline ip4_addr ip4_not(ip4_addr a)
{ return _MI4(~_I(a)); }


static inline int ip6_equal(ip6_addr a, ip6_addr b)
{ return _I0(a) == _I0(b) && _I1(a) == _I1(b) && _I2(a) == _I2(b) && _I3(a) == _I3(b); }

static inline int ip6_zero(ip6_addr a)
{ return  !_I0(a) && !_I1(a) && !_I2(a) && !_I3(a); }

static inline int ip6_nonzero(ip6_addr a)
{ return _I0(a) || _I1(a) || _I2(a) || _I3(a); }

static inline ip6_addr ip6_and(ip6_addr a, ip6_addr b)
{ return _MI6(_I0(a) & _I0(b), _I1(a) & _I1(b), _I2(a) & _I2(b), _I3(a) & _I3(b)); }

static inline ip6_addr ip6_or(ip6_addr a, ip6_addr b)
{ return _MI6(_I0(a) | _I0(b), _I1(a) | _I1(b), _I2(a) | _I2(b), _I3(a) | _I3(b)); }

static inline ip6_addr ip6_xor(ip6_addr a, ip6_addr b)
{ return _MI6(_I0(a) ^ _I0(b), _I1(a) ^ _I1(b), _I2(a) ^ _I2(b), _I3(a) ^ _I3(b)); }

static inline ip6_addr ip6_not(ip6_addr a)
{ return _MI6(~_I0(a), ~_I1(a), ~_I2(a), ~_I3(a)); }


#ifdef IPV6
#define ipa_equal(x,y) ip6_equal(x,y)
#define ipa_zero(x) ip6_zero(x)
#define ipa_nonzero(x) ip6_nonzero(x)
#define ipa_and(x,y) ip6_and(x,y)
#define ipa_or(x,y) ip6_or(x,y)
#define ipa_xor(x,y) ip6_xor(x,y)
#define ipa_not(x) ip6_not(x)
#else
#define ipa_equal(x,y) ip4_equal(x,y)
#define ipa_zero(x) ip4_zero(x)
#define ipa_nonzero(x) ip4_nonzero(x)
#define ipa_and(x,y) ip4_and(x,y)
#define ipa_or(x,y) ip4_or(x,y)
#define ipa_xor(x,y) ip4_xor(x,y)
#define ipa_not(x) ip4_not(x)
#endif



#ifdef IPV6
/*
 * A zero address is either a token for invalid/unused, or the prefix of default
 * routes. These functions should be used in the second case, where both IPv4
 * and IPv6 zero addresses should be checked.
 */

static inline int ipa_zero2(ip_addr a)
{ return  !_I0(a) && !_I1(a) && ((_I2(a) == 0) || (_I2(a) == 0xffff)) && !_I3(a); }

static inline int ipa_nonzero2(ip_addr a)
{ return _I0(a) || _I1(a) || ((_I2(a) != 0) && (_I2(a) != 0xffff)) || _I3(a); }

#else
#define ipa_zero2(x) ip4_zero(x)
#define ipa_nonzero2(x) ip4_nonzero(x)
#endif


/*
 *	Hash and compare functions
 */

static inline uint ip4_hash(ip4_addr a)
{
  /* Returns a 16-bit value */
  u32 x = _I(a);
  x ^= x >> 16;
  x ^= x << 10;
  return x & 0xffff;
}

static inline u32 ip4_hash32(ip4_addr a)
{
  /* Returns a 32-bit value, although low-order bits are not mixed */
  u32 x = _I(a);
  x ^= x << 16;
  x ^= x << 12;
  return x;
}

static inline uint ip6_hash(ip6_addr a)
{
  /* Returns a 16-bit hash key */
  u32 x = _I0(a) ^ _I1(a) ^ _I2(a) ^ _I3(a);
  return (x ^ (x >> 16) ^ (x >> 8)) & 0xffff;
}

static inline u32 ip6_hash32(ip6_addr a)
{
  /* Returns a 32-bit hash key, although low-order bits are not mixed */
  u32 x = _I0(a) ^ _I1(a) ^ _I2(a) ^ _I3(a);
  return x ^ (x << 16) ^ (x << 24);
}

static inline int ip4_compare(ip4_addr a, ip4_addr b)
{ return (_I(a) > _I(b)) - (_I(a) < _I(b)); }

int ip6_compare(ip6_addr a, ip6_addr b);


#ifdef IPV6
#define ipa_hash(x) ip6_hash(x)
#define ipa_hash32(x) ip6_hash32(x)
#define ipa_compare(x,y) ip6_compare(x,y)
#else
#define ipa_hash(x) ip4_hash(x)
#define ipa_hash32(x) ip4_hash32(x)
#define ipa_compare(x,y) ip4_compare(x,y)
#endif


/*
 *	IP address classification
 */

/* Address class */
#define IADDR_INVALID		-1
#define IADDR_SCOPE_MASK       	0xfff
#define IADDR_HOST		0x1000
#define IADDR_BROADCAST		0x2000
#define IADDR_MULTICAST		0x4000

/* Address scope */
#define SCOPE_HOST		0
#define SCOPE_LINK		1
#define SCOPE_SITE		2
#define SCOPE_ORGANIZATION	3
#define SCOPE_UNIVERSE		4
#define SCOPE_UNDEFINED		5

int ip4_classify(ip4_addr ad);
int ip6_classify(ip6_addr *a);

static inline int ip6_is_link_local(ip6_addr a)
{ return (_I0(a) & 0xffc00000) == 0xfe800000; }

static inline int ip6_is_v4mapped(ip6_addr a)
{ return _I0(a) == 0 && _I1(a) == 0 && _I2(a) == 0xffff; }

#ifdef IPV6
#define ipa_classify(x) ip6_classify(&(x))
#define ipa_is_link_local(x) ip6_is_link_local(x)
#else
#define ipa_classify(x) ip4_classify(x)
#define ipa_is_link_local(x) 0
#endif

static inline int ipa_classify_net(ip_addr a)
{ return ipa_zero2(a) ? (IADDR_HOST | SCOPE_UNIVERSE) : ipa_classify(a); }


/*
 *	Miscellaneous IP prefix manipulation
 */

static inline ip4_addr ip4_mkmask(uint n)
{ return _MI4(u32_mkmask(n)); }

static inline int ip4_masklen(ip4_addr a)
{ return u32_masklen(_I(a)); }

ip6_addr ip6_mkmask(uint n);
int ip6_masklen(ip6_addr *a);

/* ipX_pxlen() requires that x != y */
static inline uint ip4_pxlen(ip4_addr a, ip4_addr b)
{ return 31 - u32_log2(_I(a) ^ _I(b)); }

static inline uint ip6_pxlen(ip6_addr a, ip6_addr b)
{
  int i = 0;
  i += (a.addr[i] == b.addr[i]);
  i += (a.addr[i] == b.addr[i]);
  i += (a.addr[i] == b.addr[i]);
  i += (a.addr[i] == b.addr[i]);
  return 32 * i + 31 - u32_log2(a.addr[i] ^ b.addr[i]);
}

static inline u32 ip4_getbit(ip4_addr a, uint pos)
{ return _I(a) & (0x80000000 >> pos); }

static inline u32 ip6_getbit(ip6_addr a, uint pos)
{ return a.addr[pos / 32] & (0x80000000 >> (pos % 32)); }

static inline ip4_addr ip4_opposite_m1(ip4_addr a)
{ return _MI4(_I(a) ^ 1); }

static inline ip4_addr ip4_opposite_m2(ip4_addr a)
{ return _MI4(_I(a) ^ 3); }

static inline ip6_addr ip6_opposite_m1(ip6_addr a)
{ return _MI6(_I0(a), _I1(a), _I2(a), _I3(a) ^ 1); }

static inline ip6_addr ip6_opposite_m2(ip6_addr a)
{ return _MI6(_I0(a), _I1(a), _I2(a), _I3(a) ^ 3); }

ip4_addr ip4_class_mask(ip4_addr ad);

#ifdef IPV6
#define ipa_mkmask(x) ip6_mkmask(x)
#define ipa_masklen(x) ip6_masklen(&x)
#define ipa_pxlen(x,y) ip6_pxlen(x,y)
#define ipa_getbit(x,n) ip6_getbit(x,n)
#define ipa_opposite_m1(x) ip6_opposite_m1(x)
#define ipa_opposite_m2(x) ip6_opposite_m2(x)
#else
#define ipa_mkmask(x) ip4_mkmask(x)
#define ipa_masklen(x) ip4_masklen(x)
#define ipa_pxlen(x,y) ip4_pxlen(x,y)
#define ipa_getbit(x,n) ip4_getbit(x,n)
#define ipa_opposite_m1(x) ip4_opposite_m1(x)
#define ipa_opposite_m2(x) ip4_opposite_m2(x)
#endif


/*
 *	Host/network order conversions
 */

static inline ip4_addr ip4_hton(ip4_addr a)
{ return _MI4(htonl(_I(a))); }

static inline ip4_addr ip4_ntoh(ip4_addr a)
{ return _MI4(ntohl(_I(a))); }

static inline ip6_addr ip6_hton(ip6_addr a)
{ return _MI6(htonl(_I0(a)), htonl(_I1(a)), htonl(_I2(a)), htonl(_I3(a))); }

static inline ip6_addr ip6_ntoh(ip6_addr a)
{ return _MI6(ntohl(_I0(a)), ntohl(_I1(a)), ntohl(_I2(a)), ntohl(_I3(a))); }

#ifdef IPV6
#define ipa_hton(x) x = ip6_hton(x)
#define ipa_ntoh(x) x = ip6_ntoh(x)
#else
#define ipa_hton(x) x = ip4_hton(x)
#define ipa_ntoh(x) x = ip4_ntoh(x)
#endif


/*
 *	Unaligned data access (in network order)
 */

static inline ip4_addr get_ip4(void *buf)
{
  return _MI4(get_u32(buf));
}

static inline ip6_addr get_ip6(void *buf)
{
  ip6_addr a;
  memcpy(&a, buf, 16);
  return ip6_ntoh(a);
}

static inline void * put_ip4(void *buf, ip4_addr a)
{
  put_u32(buf, _I(a));
  return buf+4;
}

static inline void * put_ip6(void *buf, ip6_addr a)
{
  a = ip6_hton(a);
  memcpy(buf, &a, 16);
  return buf+16;
}

// XXXX these functions must be redesigned or removed
#ifdef IPV6
#define get_ipa(x) get_ip6(x)
#define put_ipa(x,y) put_ip6(x,y)
#else
#define get_ipa(x) get_ip4(x)
#define put_ipa(x,y) put_ip4(x,y)
#endif


/*
 *	Binary/text form conversions
 */

char *ip4_ntop(ip4_addr a, char *b);
char *ip6_ntop(ip6_addr a, char *b);

static inline char * ip4_ntox(ip4_addr a, char *b)
{ return b + bsprintf(b, "%08x", _I(a)); }

static inline char * ip6_ntox(ip6_addr a, char *b)
{ return b + bsprintf(b, "%08x.%08x.%08x.%08x", _I0(a), _I1(a), _I2(a), _I3(a)); }

int ip4_pton(const char *a, ip4_addr *o);
int ip6_pton(const char *a, ip6_addr *o);

// XXXX these functions must be redesigned or removed
#ifdef IPV6
#define ipa_ntop(x,y) ip6_ntop(x,y)
#define ipa_ntox(x,y) ip6_ntox(x,y)
#define ipa_pton(x,y) ip6_pton(x,y)
#else
#define ipa_ntop(x,y) ip4_ntop(x,y)
#define ipa_ntox(x,y) ip4_ntox(x,y)
#define ipa_pton(x,y) ip4_pton(x,y)
#endif


/*
 *	Miscellaneous
 */

// XXXX review this

#define ip_is_prefix(a,l) (!ipa_nonzero(ipa_and(a, ipa_not(ipa_mkmask(l)))))
#define ipa_in_net(x,n,p) (ipa_zero(ipa_and(ipa_xor((n),(x)),ipa_mkmask(p))))
#define net_in_net(n1,l1,n2,l2) (((l1) >= (l2)) && (ipa_zero(ipa_and(ipa_xor((n1),(n2)),ipa_mkmask(l2)))))

char *ip_scope_text(uint);

struct prefix {
  ip_addr addr;
  uint len;
};


#endif