badvpn/misc/ipaddr6.h
2014-11-26 19:15:26 +01:00

384 lines
10 KiB
C

/**
* @file ipaddr6.h
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* @section DESCRIPTION
*
* IPv6 address parsing functions.
*/
#ifndef BADVPN_MISC_IPADDR6_H
#define BADVPN_MISC_IPADDR6_H
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <limits.h>
#include <misc/debug.h>
#include <misc/byteorder.h>
#include <misc/parse_number.h>
#include <misc/find_char.h>
#include <misc/print_macros.h>
#include <misc/memref.h>
struct ipv6_addr {
uint8_t bytes[16];
};
struct ipv6_ifaddr {
struct ipv6_addr addr;
int prefix;
};
static int ipaddr6_parse_ipv6_addr (MemRef name, struct ipv6_addr *out_addr);
static int ipaddr6_parse_ipv6_prefix (MemRef str, int *out_num);
static int ipaddr6_parse_ipv6_ifaddr (MemRef str, struct ipv6_ifaddr *out);
static int ipaddr6_ipv6_ifaddr_from_addr_mask (struct ipv6_addr addr, struct ipv6_addr mask, struct ipv6_ifaddr *out);
static void ipaddr6_ipv6_mask_from_prefix (int prefix, struct ipv6_addr *out_mask);
static int ipaddr6_ipv6_prefix_from_mask (struct ipv6_addr mask, int *out_prefix);
static int ipaddr6_ipv6_addrs_in_network (struct ipv6_addr addr1, struct ipv6_addr addr2, int netprefix);
#define IPADDR6_PRINT_MAX 44
static void ipaddr6_print_addr (struct ipv6_addr addr, char *out_buf);
static void ipaddr6_print_ifaddr (struct ipv6_ifaddr addr, char *out_buf);
int ipaddr6_parse_ipv6_addr (MemRef name, struct ipv6_addr *out_addr)
{
int num_blocks = 0;
int compress_pos = -1;
uint16_t block = 0;
int empty = 1;
size_t i = 0;
while (i < name.len) {
if (name.ptr[i] == '.') {
goto ipv4_ending;
} else if (name.ptr[i] == ':') {
int is_double = (i + 1 < name.len && name.ptr[i + 1] == ':');
if (i > 0) {
if (empty || num_blocks == 7) {
return 0;
}
out_addr->bytes[2 * num_blocks + 0] = block >> 8;
out_addr->bytes[2 * num_blocks + 1] = block & 0xFF;
num_blocks++;
block = 0;
empty = 1;
}
else if (!is_double) {
return 0;
}
if (is_double) {
if (compress_pos != -1) {
return 0;
}
compress_pos = num_blocks;
}
i += 1 + is_double;
} else {
int digit = decode_hex_digit(name.ptr[i]);
if (digit < 0) {
return 0;
}
if (block > UINT16_MAX / 16) {
return 0;
}
block *= 16;
if (digit > UINT16_MAX - block) {
return 0;
}
block += digit;
empty = 0;
i += 1;
}
}
if (!empty) {
out_addr->bytes[2 * num_blocks + 0] = block >> 8;
out_addr->bytes[2 * num_blocks + 1] = block & 0xFF;
num_blocks++;
}
else if (num_blocks != compress_pos) {
return 0;
}
ipv4_done:
if (compress_pos == -1) {
if (num_blocks != 8) {
return 0;
}
compress_pos = 0;
}
int num_rear = num_blocks - compress_pos;
memmove(out_addr->bytes + 2 * (8 - num_rear), out_addr->bytes + 2 * compress_pos, 2 * num_rear);
memset(out_addr->bytes + 2 * compress_pos, 0, 2 * (8 - num_rear - compress_pos));
return 1;
ipv4_ending:
if (empty || (num_blocks == 0 && compress_pos == -1)) {
return 0;
}
while (name.ptr[i - 1] != ':') {
i--;
}
uint8_t bytes[4];
int cur_byte = 0;
uint8_t byte = 0;
empty = 1;
while (i < name.len) {
if (name.ptr[i] == '.') {
if (empty || cur_byte == 3) {
return 0;
}
bytes[cur_byte] = byte;
cur_byte++;
byte = 0;
empty = 1;
} else {
if (!empty && byte == 0) {
return 0;
}
int digit = decode_decimal_digit(name.ptr[i]);
if (digit < 0) {
return 0;
}
if (byte > UINT8_MAX / 10) {
return 0;
}
byte *= 10;
if (digit > UINT8_MAX - byte) {
return 0;
}
byte += digit;
empty = 0;
}
i++;
}
if (cur_byte != 3 || empty) {
return 0;
}
bytes[cur_byte] = byte;
if (8 - num_blocks < 2) {
return 0;
}
memcpy(out_addr->bytes + 2 * num_blocks, bytes, 4);
num_blocks += 2;
goto ipv4_done;
}
int ipaddr6_parse_ipv6_prefix (MemRef str, int *out_num)
{
uintmax_t d;
if (!parse_unsigned_integer(str, &d)) {
return 0;
}
if (d > 128) {
return 0;
}
*out_num = d;
return 1;
}
int ipaddr6_parse_ipv6_ifaddr (MemRef str, struct ipv6_ifaddr *out)
{
size_t slash_pos;
if (!MemRef_FindChar(str, '/', &slash_pos)) {
return 0;
}
return (ipaddr6_parse_ipv6_addr(MemRef_SubTo(str, slash_pos), &out->addr) &&
ipaddr6_parse_ipv6_prefix(MemRef_SubFrom(str, slash_pos + 1), &out->prefix));
}
int ipaddr6_ipv6_ifaddr_from_addr_mask (struct ipv6_addr addr, struct ipv6_addr mask, struct ipv6_ifaddr *out)
{
int prefix;
if (!ipaddr6_ipv6_prefix_from_mask(mask, &prefix)) {
return 0;
}
out->addr = addr;
out->prefix = prefix;
return 1;
}
void ipaddr6_ipv6_mask_from_prefix (int prefix, struct ipv6_addr *out_mask)
{
ASSERT(prefix >= 0)
ASSERT(prefix <= 128)
int quot = prefix / 8;
int rem = prefix % 8;
if (quot > 0) {
memset(out_mask->bytes, UINT8_MAX, quot);
}
if (16 - quot > 0) {
memset(out_mask->bytes + quot, 0, 16 - quot);
}
for (int i = 0; i < rem; i++) {
out_mask->bytes[quot] |= (uint8_t)1 << (8 - i - 1);
}
}
int ipaddr6_ipv6_prefix_from_mask (struct ipv6_addr mask, int *out_prefix)
{
int prefix = 0;
int i = 0;
while (i < 16 && mask.bytes[i] == UINT8_MAX) {
prefix += 8;
i++;
}
if (i < 16) {
uint8_t t = 0;
int j;
for (j = 0; j <= 8; j++) {
if (mask.bytes[i] == t) {
break;
}
if (j < 8) {
t |= ((uint8_t)1 << (8 - j - 1));
}
}
if (!(j <= 8)) {
return 0;
}
prefix += j;
i++;
while (i < 16) {
if (mask.bytes[i] != 0) {
return 0;
}
i++;
}
}
*out_prefix = prefix;
return 1;
}
int ipaddr6_ipv6_addrs_in_network (struct ipv6_addr addr1, struct ipv6_addr addr2, int netprefix)
{
ASSERT(netprefix >= 0)
ASSERT(netprefix <= 128)
int quot = netprefix / 8;
int rem = netprefix % 8;
if (memcmp(addr1.bytes, addr2.bytes, quot)) {
return 0;
}
if (rem == 0) {
return 1;
}
uint8_t t = 0;
for (int i = 0; i < rem; i++) {
t |= (uint8_t)1 << (8 - i - 1);
}
return ((addr1.bytes[quot] & t) == (addr2.bytes[quot] & t));
}
void ipaddr6_print_addr (struct ipv6_addr addr, char *out_buf)
{
int largest_start = 0;
int largest_len = 0;
int current_start = 0;
int current_len = 0;
for (int i = 0; i < 8; i++) {
if (addr.bytes[2 * i] == 0 && addr.bytes[2 * i + 1] == 0) {
current_len++;
if (current_len > largest_len) {
largest_start = current_start;
largest_len = current_len;
}
} else {
current_start = i + 1;
current_len = 0;
}
}
if (largest_len > 1) {
for (int i = 0; i < largest_start; i++) {
uint16_t block = ((uint16_t)addr.bytes[2 * i] << 8) | addr.bytes[2 * i + 1];
out_buf += sprintf(out_buf, "%"PRIx16":", block);
}
if (largest_start == 0) {
out_buf += sprintf(out_buf, ":");
}
for (int i = largest_start + largest_len; i < 8; i++) {
uint16_t block = ((uint16_t)addr.bytes[2 * i] << 8) | addr.bytes[2 * i + 1];
out_buf += sprintf(out_buf, ":%"PRIx16, block);
}
if (largest_start + largest_len == 8) {
out_buf += sprintf(out_buf, ":");
}
} else {
const char *prefix = "";
for (int i = 0; i < 8; i++) {
uint16_t block = ((uint16_t)addr.bytes[2 * i] << 8) | addr.bytes[2 * i + 1];
out_buf += sprintf(out_buf, "%s%"PRIx16, prefix, block);
prefix = ":";
}
}
}
void ipaddr6_print_ifaddr (struct ipv6_ifaddr addr, char *out_buf)
{
ASSERT(addr.prefix >= 0)
ASSERT(addr.prefix <= 128)
ipaddr6_print_addr(addr.addr, out_buf);
sprintf(out_buf + strlen(out_buf), "/%d", addr.prefix);
}
#endif