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bird/lib/ip.c
Maria Matejka a1b61a271a IPv6 address parser: fail on incomplete addresses
2020-05-01 15:19:12 +02:00

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/*
* BIRD Library -- IP address functions
*
* (c) 1998--2000 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
/**
* DOC: IP addresses
*
* BIRD uses its own abstraction of IP address in order to share the same
* code for both IPv4 and IPv6. IP addresses are represented as entities
* of type &ip_addr which are never to be treated as numbers and instead
* they must be manipulated using the following functions and macros.
*/
#include <stdlib.h>
#include "nest/bird.h"
#include "lib/ip.h"
int
ip6_compare(ip6_addr a, ip6_addr b)
{
int i;
for (i=0; i<4; i++)
if (a.addr[i] > b.addr[i])
return 1;
else if (a.addr[i] < b.addr[i])
return -1;
return 0;
}
ip6_addr
ip6_mkmask(uint n)
{
ip6_addr a;
int i;
for (i=0; i<4; i++)
{
if (!n)
a.addr[i] = 0;
else if (n >= 32)
{
a.addr[i] = ~0;
n -= 32;
}
else
{
a.addr[i] = u32_mkmask(n);
n = 0;
}
}
return a;
}
uint
ip6_masklen(ip6_addr *a)
{
int i, j, n;
for (i=0, n=0; i<4; i++, n+=32)
if (a->addr[i] != ~0U)
{
j = u32_masklen(a->addr[i]);
if (j == 255)
return j;
n += j;
while (++i < 4)
if (a->addr[i])
return 255;
break;
}
return n;
}
int
ip4_classify(ip4_addr ad)
{
u32 a = _I(ad);
u32 b = a >> 24U;
if (b && b <= 0xdf)
{
if (b == 0x7f)
return IADDR_HOST | SCOPE_HOST;
else if ((b == 0x0a) ||
((a & 0xffff0000) == 0xc0a80000) ||
((a & 0xfff00000) == 0xac100000))
return IADDR_HOST | SCOPE_SITE;
else
return IADDR_HOST | SCOPE_UNIVERSE;
}
if (b >= 0xe0 && b <= 0xef)
return IADDR_MULTICAST | SCOPE_UNIVERSE;
if (a == 0xffffffff)
return IADDR_BROADCAST | SCOPE_LINK;
return IADDR_INVALID;
}
int
ip6_classify(ip6_addr *a)
{
u32 x = a->addr[0];
if ((x & 0xe0000000) == 0x20000000) /* 2000::/3 Aggregatable Global Unicast Address */
return IADDR_HOST | SCOPE_UNIVERSE;
if ((x & 0xffc00000) == 0xfe800000) /* fe80::/10 Link-Local Address */
return IADDR_HOST | SCOPE_LINK;
if ((x & 0xffc00000) == 0xfec00000) /* fec0::/10 Site-Local Address */
return IADDR_HOST | SCOPE_SITE;
if ((x & 0xfe000000) == 0xfc000000) /* fc00::/7 Unique Local Unicast Address (RFC 4193) */
return IADDR_HOST | SCOPE_SITE;
if ((x & 0xff000000) == 0xff000000) /* ff00::/8 Multicast Address */
{
uint scope = (x >> 16) & 0x0f;
switch (scope)
{
case 1: return IADDR_MULTICAST | SCOPE_HOST;
case 2: return IADDR_MULTICAST | SCOPE_LINK;
case 5: return IADDR_MULTICAST | SCOPE_SITE;
case 8: return IADDR_MULTICAST | SCOPE_ORGANIZATION;
case 14: return IADDR_MULTICAST | SCOPE_UNIVERSE;
default: return IADDR_MULTICAST | SCOPE_UNDEFINED;
}
}
if (!x && !a->addr[1])
{
u32 a2 = a->addr[2];
u32 a3 = a->addr[3];
if (a2 == 0 && a3 == 1)
return IADDR_HOST | SCOPE_HOST; /* Loopback address */
if (a2 == 0)
return ip4_classify(_MI4(a3)); /* IPv4 compatible addresses */
if (a2 == 0xffff)
return ip4_classify(_MI4(a3)); /* IPv4 mapped addresses */
return IADDR_INVALID;
}
return IADDR_HOST | SCOPE_UNDEFINED;
}
/*
* Conversion of IPv6 address to presentation format and vice versa.
* Heavily inspired by routines written by Paul Vixie for the BIND project
* and of course by RFC 2373.
*/
char *
ip4_ntop(ip4_addr a, char *b)
{
u32 x = _I(a);
return b + bsprintf(b, "%d.%d.%d.%d", (x >> 24) & 0xff, (x >> 16) & 0xff, (x >> 8) & 0xff, x & 0xff);
}
char *
ip6_ntop(ip6_addr a, char *b)
{
u16 words[8];
int bestpos, bestlen, curpos, curlen, i;
/* First of all, preprocess the address and find the longest run of zeros */
bestlen = bestpos = curpos = curlen = 0;
for (i=0; i<8; i++)
{
u32 x = a.addr[i/2];
words[i] = ((i%2) ? x : (x >> 16)) & 0xffff;
if (words[i])
curlen = 0;
else
{
if (!curlen)
curpos = i;
curlen++;
if (curlen > bestlen)
{
bestpos = curpos;
bestlen = curlen;
}
}
}
if (bestlen < 2)
bestpos = -1;
/* Is it an encapsulated IPv4 address? */
if (!bestpos && ((bestlen == 5 && a.addr[2] == 0xffff) || (bestlen == 6)))
{
u32 x = a.addr[3];
b += bsprintf(b, "::%s%d.%d.%d.%d",
a.addr[2] ? "ffff:" : "",
(x >> 24) & 0xff,
(x >> 16) & 0xff,
(x >> 8) & 0xff,
x & 0xff);
return b;
}
/* Normal IPv6 formatting, compress the largest sequence of zeros */
for (i=0; i<8; i++)
{
if (i == bestpos)
{
i += bestlen - 1;
*b++ = ':';
if (i == 7)
*b++ = ':';
}
else
{
if (i)
*b++ = ':';
b += bsprintf(b, "%x", words[i]);
}
}
*b = 0;
return b;
}
int
ip4_pton(const char *a, ip4_addr *o)
{
int i;
unsigned long int l;
u32 ia = 0;
i=4;
while (i--)
{
char *d, *c = strchr(a, '.');
if (!c != !i)
return 0;
l = bstrtoul10(a, &d);
if (((d != c) && *d) || (l > 255))
return 0;
ia = (ia << 8) | l;
if (c)
c++;
a = c;
}
*o = ip4_from_u32(ia);
return 1;
}
int
ip6_pton(const char *a, ip6_addr *o)
{
u16 words[8];
int i, j, k, l, hfil;
const char *start;
if (!a[0]) /* Empty string check */
return 0;
if (a[0] == ':') /* Leading :: */
{
if (a[1] != ':')
return 0;
a++;
}
hfil = -1;
i = 0;
while (*a)
{
if (*a == ':') /* :: */
{
if (hfil >= 0)
return 0;
hfil = i;
a++;
continue;
}
j = 0;
l = 0;
start = a;
for (;;)
{
if (*a >= '0' && *a <= '9')
k = *a++ - '0';
else if (*a >= 'A' && *a <= 'F')
k = *a++ - 'A' + 10;
else if (*a >= 'a' && *a <= 'f')
k = *a++ - 'a' + 10;
else
break;
j = (j << 4) + k;
if (j >= 0x10000 || ++l > 4)
return 0;
}
if (*a == ':' && a[1])
a++;
else if (*a == '.' && (i == 6 || (i < 6 && hfil >= 0)))
{ /* Embedded IPv4 address */
ip4_addr x;
if (!ip4_pton(start, &x))
return 0;
words[i++] = _I(x) >> 16;
words[i++] = _I(x);
break;
}
else if (*a)
return 0;
if (i >= 8)
return 0;
words[i++] = j;
}
/* Replace :: with an appropriate number of zeros */
if (hfil >= 0)
{
j = 8 - i;
for (i=7; i-j >= hfil; i--)
words[i] = words[i-j];
for (; i>=hfil; i--)
words[i] = 0;
}
else if (i != 8) /* Incomplete address */
return 0;
/* Convert the address to ip6_addr format */
for (i=0; i<4; i++)
o->addr[i] = (words[2*i] << 16) | words[2*i+1];
return 1;
}
/**
* ip_scope_text - get textual representation of address scope
* @scope: scope (%SCOPE_xxx)
*
* Returns a pointer to a textual name of the scope given.
*/
char *
ip_scope_text(uint scope)
{
static char *scope_table[] = { "host", "link", "site", "org", "univ", "undef" };
if (scope > SCOPE_UNDEFINED)
return "?";
else
return scope_table[scope];
}
ip4_addr
ip4_class_mask(ip4_addr ad)
{
u32 m, a = _I(ad);
if (a == 0x00000000)
m = 0x00000000;
else if (a < 0x80000000)
m = 0xff000000;
else if (a < 0xc0000000)
m = 0xffff0000;
else
m = 0xffffff00;
if (a & ~m)
m = 0xffffffff;
return _MI4(m);
}
#if 0
/**
* ipa_equal - compare two IP addresses for equality
* @x: IP address
* @y: IP address
*
* ipa_equal() returns 1 if @x and @y represent the same IP address, else 0.
*/
int ipa_equal(ip_addr x, ip_addr y) { DUMMY }
/**
* ipa_nonzero - test if an IP address is defined
* @x: IP address
*
* ipa_nonzero returns 1 if @x is a defined IP address (not all bits are zero),
* else 0.
*
* The undefined all-zero address is reachable as a |IPA_NONE| macro.
*/
int ipa_nonzero(ip_addr x) { DUMMY }
/**
* ipa_and - compute bitwise and of two IP addresses
* @x: IP address
* @y: IP address
*
* This function returns a bitwise and of @x and @y. It's primarily
* used for network masking.
*/
ip_addr ipa_and(ip_addr x, ip_addr y) { DUMMY }
/**
* ipa_or - compute bitwise or of two IP addresses
* @x: IP address
* @y: IP address
*
* This function returns a bitwise or of @x and @y.
*/
ip_addr ipa_or(ip_addr x, ip_addr y) { DUMMY }
/**
* ipa_xor - compute bitwise xor of two IP addresses
* @x: IP address
* @y: IP address
*
* This function returns a bitwise xor of @x and @y.
*/
ip_addr ipa_xor(ip_addr x, ip_addr y) { DUMMY }
/**
* ipa_not - compute bitwise negation of two IP addresses
* @x: IP address
*
* This function returns a bitwise negation of @x.
*/
ip_addr ipa_not(ip_addr x) { DUMMY }
/**
* ipa_mkmask - create a netmask
* @x: prefix length
*
* This function returns an &ip_addr corresponding of a netmask
* of an address prefix of size @x.
*/
ip_addr ipa_mkmask(int x) { DUMMY }
/**
* ipa_masklen - calculate netmask length
* @x: IP address
*
* This function checks whether @x represents a valid netmask and
* returns the size of the associate network prefix or -1 for invalid
* mask.
*/
int ipa_masklen(ip_addr x) { DUMMY }
/**
* ipa_hash - hash IP addresses
* @x: IP address
*
* ipa_hash() returns a 16-bit hash value of the IP address @x.
*/
int ipa_hash(ip_addr x) { DUMMY }
/**
* ipa_hton - convert IP address to network order
* @x: IP address
*
* Converts the IP address @x to the network byte order.
*
* Beware, this is a macro and it alters the argument!
*/
void ipa_hton(ip_addr x) { DUMMY }
/**
* ipa_ntoh - convert IP address to host order
* @x: IP address
*
* Converts the IP address @x from the network byte order.
*
* Beware, this is a macro and it alters the argument!
*/
void ipa_ntoh(ip_addr x) { DUMMY }
/**
* ipa_classify - classify an IP address
* @x: IP address
*
* ipa_classify() returns an address class of @x, that is a bitwise or
* of address type (%IADDR_INVALID, %IADDR_HOST, %IADDR_BROADCAST, %IADDR_MULTICAST)
* with address scope (%SCOPE_HOST to %SCOPE_UNIVERSE) or -1 (%IADDR_INVALID)
* for an invalid address.
*/
int ipa_classify(ip_addr x) { DUMMY }
/**
* ip4_class_mask - guess netmask according to address class
* @x: IPv4 address
*
* This function (available in IPv4 version only) returns a
* network mask according to the address class of @x. Although
* classful addressing is nowadays obsolete, there still live
* routing protocols transferring no prefix lengths nor netmasks
* and this function could be useful to them.
*/
ip4_addr ip4_class_mask(ip4_addr x) { DUMMY }
/**
* ipa_from_u32 - convert IPv4 address to an integer
* @x: IP address
*
* This function takes an IPv4 address and returns its numeric
* representation.
*/
u32 ipa_from_u32(ip_addr x) { DUMMY }
/**
* ipa_to_u32 - convert integer to IPv4 address
* @x: a 32-bit integer
*
* ipa_to_u32() takes a numeric representation of an IPv4 address
* and converts it to the corresponding &ip_addr.
*/
ip_addr ipa_to_u32(u32 x) { DUMMY }
/**
* ipa_compare - compare two IP addresses for order
* @x: IP address
* @y: IP address
*
* The ipa_compare() function takes two IP addresses and returns
* -1 if @x is less than @y in canonical ordering (lexicographical
* order of the bit strings), 1 if @x is greater than @y and 0
* if they are the same.
*/
int ipa_compare(ip_addr x, ip_addr y) { DUMMY }
/**
* ipa_build6 - build an IPv6 address from parts
* @a1: part #1
* @a2: part #2
* @a3: part #3
* @a4: part #4
*
* ipa_build() takes @a1 to @a4 and assembles them to a single IPv6
* address. It's used for example when a protocol wants to bind its
* socket to a hard-wired multicast address.
*/
ip_addr ipa_build6(u32 a1, u32 a2, u32 a3, u32 a4) { DUMMY }
/**
* ip_ntop - convert IP address to textual representation
* @a: IP address
* @buf: buffer of size at least %STD_ADDRESS_P_LENGTH
*
* This function takes an IP address and creates its textual
* representation for presenting to the user.
*/
char *ip_ntop(ip_addr a, char *buf) { DUMMY }
/**
* ip_ntox - convert IP address to hexadecimal representation
* @a: IP address
* @buf: buffer of size at least %STD_ADDRESS_P_LENGTH
*
* This function takes an IP address and creates its hexadecimal
* textual representation. Primary use: debugging dumps.
*/
char *ip_ntox(ip_addr a, char *buf) { DUMMY }
/**
* ip_pton - parse textual representation of IP address
* @a: textual representation
* @o: where to put the resulting address
*
* This function parses a textual IP address representation and
* stores the decoded address to a variable pointed to by @o.
* Returns 0 if a parse error has occurred, else 0.
*/
int ip_pton(char *a, ip_addr *o) { DUMMY }
#endif
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