#include "fmt.h"
#include "ip.h"
#include "scan.h"
#include "str.h"

/**
  @file ip4.c
  @author djb, fefe, feh, kp
  @source ucspi-tcp, ucspi-tcp6
  @brief handling of IPv4 addresses
*/

/**
 @brief ip4_fmt
        converts IPv4 address to dotted decimal string format
 @param input:  IPv4 char array
        output: IPv4 address string
 @return int length of address (ok > 0)
 */

unsigned int ip4_fmt(char *s, char ip[4])
{
  unsigned int len;
  unsigned int i;

  len = 0;
  // clang-format off
  i = fmt_ulong(s,(unsigned long) (unsigned char) ip[0]); len += i; if (s) s += i;
  if (s) { *s++ = '.'; } ++len;
  i = fmt_ulong(s,(unsigned long) (unsigned char) ip[1]); len += i; if (s) s += i;
  if (s) { *s++ = '.'; } ++len;
  i = fmt_ulong(s,(unsigned long) (unsigned char) ip[2]); len += i; if (s) s += i;
  if (s) { *s++ = '.'; } ++len;
  i = fmt_ulong(s,(unsigned long) (unsigned char) ip[3]); len += i; if (s) s += i;
  // clang-format on
  return len;
}

/**
 @brief ia4_fmt
        converts IPv4 address into DNS inverse nibble format
 @param input:  IPv4 char array
        output: IPv4 address string
 @return int length of address (ok > 0)
 */

unsigned int ia4_fmt(char *s, char ip[4])
{
  unsigned int i;
  unsigned int len;

  len = 0;
  // clang-format off
  i = fmt_ulong(s,(unsigned long) ip[3]); len += i; if (s) s += i;
  i = fmt_str(s,"."); len += i; if (s) s += i;
  i = fmt_ulong(s,(unsigned long) ip[2]); len += i; if (s) s += i;
  i = fmt_str(s,"."); len += i; if (s) s += i;
  i = fmt_ulong(s,(unsigned long) ip[1]); len += i; if (s) s += i;
  i = fmt_str(s,"."); len += i; if (s) s += i;
  i = fmt_ulong(s,(unsigned long) ip[0]); len += i; if (s) s += i;
  i = fmt_str(s,".in-addr.arpa."); len += i; if (s) s += i;
  // clang-format on
  return len;
}

/**
 @brief ip4_scan
        parse IPv4 address string and convert to IP address array
 @param input:  IPv4 address string
        output: IPv4 char array
 @return int length of ip_address (ok > 0)
 */

unsigned int ip4_scan(const char *s, char ip[4])
{
  unsigned int i;
  unsigned int len;
  unsigned long u;

  byte_zero(ip, 4);
  len = 0;
  // clang-format off
  i = scan_ulong((char *)s,&u); if (!i) { return 0; } ip[0] = u; s += i; len += i;
  if (*s != '.') { return 0; } ++s; ++len;
  i = scan_ulong((char *)s,&u); if (!i) { return 0; } ip[1] = u; s += i; len += i;
  if (*s != '.') { return 0; } ++s; ++len;
  i = scan_ulong((char *)s,&u); if (!i) { return 0; } ip[2] = u; s += i; len += i;
  if (*s != '.') { return 0; } ++s; ++len;
  i = scan_ulong((char *)s,&u); if (!i) { return 0; } ip[3] = u; s += i; len += i;
  // clang-format on
  return len;
}

/**
 @brief ip4_scanbracket
        parse IPv4 address string enclosed in brackets and convert to IP address array
 @param input:  IPv4 char array
        output: IPv4 char array
 @return int length of ip_address (ok > 0)
 */

unsigned int ip4_scanbracket(const char *s, char ip[4])
{
  unsigned int len;

  if (*s != '[') return 0;
  len = ip4_scan(s + 1, ip);
  if (!len) return 0;
  if (s[len + 1] != ']') return 0;
  return len + 2;
}

/**
 @brief ip4_cidr
        parse IPv4 address string
        concatinated with the prefix length:  192.168.1/24
 @param input:  IPv6 char array
        output: IPv6 char array, long plen
 @return int length of ip6_address/ip
 */

unsigned int ip4_cidr(char *s, char ip[4], unsigned long *plen)
{
  unsigned int j = 0;
  *plen = 32UL;

  j = str_chr(s, '/');
  if (s[j] == '/') {
    s[j] = 0;
    j = scan_ulong(s + j + 1, plen);
  }
  return ip4_scan((const char *)s, ip);
}

/**
 @brief ip4_bytestring
        parse IPv4 address and represent as char string with length prefix
 @param input:  IPv4 char array, prefix length
        output: pointer to stralloc bytestring
 @return n: number of bytes, if ok; -1: memory shortage; -2: input error
 */

unsigned int ip4_bytestring(stralloc *ipstring, char ip[4], int prefix)
{
  int i, j, n = 0;
  unsigned char number;

  if (!stralloc_readyplus(ipstring, 32)) return -1;
  if (!stralloc_copys(ipstring, "")) return -1;

  for (i = 0; i < 4; i++) {
    number = (unsigned char)ip[i];
    if (number > 255) return -2;

    for (j = 7; j >= 0; j--) {
      if (number & (1 << j)) {
        n++;
        if (!stralloc_cats(ipstring, "1")) return -1;
      } else {
        n++;
        if (!stralloc_cats(ipstring, "0")) return -1;
      }
      prefix--;
      if (!prefix) goto DONE;
    }
  }

DONE:
  if (!stralloc_0(ipstring)) return 1;

  return n;
}