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bird/lib/ip.h
Ondrej Zajicek (work) 71c18d9f53 Trie: Simplify network matching code 
Introduce ipX_prefix_equal() and use it to simplify network matching code.
2021-11-13 21:11:18 +01:00

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/*
* 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 "sysdep/unix/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 IP6_BABEL_ROUTERS ipa_build6(0xFF020000, 0, 0, 0x00010006)
#define IP4_NONE _MI4(0)
#define IP6_NONE _MI6(0,0,0,0)
#define IP4_MAX_PREFIX_LENGTH 32
#define IP6_MAX_PREFIX_LENGTH 128
#define IP4_MAX_TEXT_LENGTH 15 /* "255.255.255.255" */
#define IP6_MAX_TEXT_LENGTH 39 /* "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff" */
#define IPA_MAX_TEXT_LENGTH 39
#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
#define MPLS_NULL 3
/* IANA Address Family Numbers */
/* https://www.iana.org/assignments/address-family-numbers/address-family-numbers.xhtml */
/* Would use AF_ prefix, but that collides with POSIX address family numbers */
#define AFI_IPV4 1
#define AFI_IPV6 2
#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) ((u32) (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])
/* 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)
#define ipa_is_ip6(a) (! ip6_is_v4mapped(a))
#define IPA_NONE4 ipa_from_ip4(IP4_NONE)
#define IPA_NONE6 ipa_from_ip6(IP6_NONE)
/*
* 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)); }
#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)
/*
* 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); }
/*
* Hash and compare functions
*/
static inline u32 ip4_hash(ip4_addr a)
{ return u32_hash(_I(a)); }
static inline u32 ip6_hash(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);
#define ipa_hash(x) ip6_hash(x)
#define ipa_compare(x,y) ip6_compare(x,y)
/*
* 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; }
#define ipa_classify(x) ip6_classify(&(x))
#define ipa_is_link_local(x) ip6_is_link_local(x)
static inline int ip4_is_unicast(ip4_addr a)
{ return _I(a) < 0xe0000000; }
/* XXXX remove */
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 uint ip4_masklen(ip4_addr a)
{ return u32_masklen(_I(a)); }
ip6_addr ip6_mkmask(uint n);
uint 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 int ip4_prefix_equal(ip4_addr a, ip4_addr b, uint n)
{
return (_I(a) ^ _I(b)) < ((u64) 1 << (32 - n));
}
static inline int ip6_prefix_equal(ip6_addr a, ip6_addr b, uint n)
{
uint n0 = n / 32;
uint n1 = n % 32;
return
((n0 <= 0) || (_I0(a) == _I0(b))) &&
((n0 <= 1) || (_I1(a) == _I1(b))) &&
((n0 <= 2) || (_I2(a) == _I2(b))) &&
((n0 <= 3) || (_I3(a) == _I3(b))) &&
(!n1 || ((a.addr[n0] ^ b.addr[n0]) < (1u << (32 - n1))));
}
static inline u32 ip4_getbit(ip4_addr a, uint pos)
{ return (_I(a) >> (31 - pos)) & 1; }
static inline u32 ip4_getbits(ip4_addr a, uint pos, uint n)
{ return (_I(a) >> ((32 - n) - pos)) & ((1u << n) - 1); }
static inline u32 ip6_getbit(ip6_addr a, uint pos)
{ return (a.addr[pos / 32] >> (31 - (pos % 32))) & 0x1; }
static inline u32 ip6_getbits(ip6_addr a, uint pos, uint n)
{ return (a.addr[pos / 32] >> ((32 - n) - (pos % 32))) & ((1u << n) - 1); }
static inline u32 ip4_setbit(ip4_addr *a, uint pos)
{ return _I(*a) |= (0x80000000 >> pos); }
static inline u32 ip6_setbit(ip6_addr *a, uint pos)
{ return a->addr[pos / 32] |= (0x80000000 >> (pos % 32)); }
static inline u32 ip4_clrbit(ip4_addr *a, uint pos)
{ return _I(*a) &= ~(0x80000000 >> pos); }
static inline u32 ip6_clrbit(ip6_addr *a, uint pos)
{ return a->addr[pos / 32] &= ~(0x80000000 >> (pos % 32)); }
static inline ip4_addr ip4_setbits(ip4_addr a, uint pos, uint val)
{ _I(a) |= val << (31 - pos); return a; }
static inline ip6_addr ip6_setbits(ip6_addr a, uint pos, uint val)
{ a.addr[pos / 32] |= val << (31 - pos % 32); return a; }
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);
#define ipa_opposite_m1(x) ip6_opposite_m1(x)
#define ipa_opposite_m2(x) ip6_opposite_m2(x)
/*
* 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))); }
#define MPLS_MAX_LABEL_STACK 8
typedef struct mpls_label_stack {
uint len;
u32 stack[MPLS_MAX_LABEL_STACK];
} mpls_label_stack;
static inline int
mpls_get(const char *buf, int buflen, u32 *stack)
{
for (int i=0; (i<MPLS_MAX_LABEL_STACK) && (i*4+3 < buflen); i++)
{
u32 s = get_u32(buf + i*4);
stack[i] = s >> 12;
if (s & 0x100)
return i+1;
}
return -1;
}
static inline int
mpls_put(char *buf, int len, u32 *stack)
{
for (int i=0; i<len; i++)
put_u32(buf + i*4, stack[i] << 12 | (i+1 == len ? 0x100 : 0));
return len*4;
}
/*
* Unaligned data access (in network order)
*/
static inline ip4_addr get_ip4(const void *buf)
{
return _MI4(get_u32(buf));
}
static inline ip6_addr get_ip6(const 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;
}
/*
* 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);
/*
* Miscellaneous
*/
char *ip_scope_text(uint);
#endif
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