/*

* Various string utils and parsing functions

* (C) 1999-2007,2013,2014,2015,2018 Jack Lloyd

* (C) 2015 Simon Warta (Kullo GmbH)

* (C) 2017 René Korthaus, Rohde & Schwarz Cybersecurity

*

* Botan is released under the Simplified BSD License (see license.txt)

*/

#include <botan/internal/parsing.h>

#include <botan/internal/loadstor.h>

#include <botan/exceptn.h>

#include <algorithm>

#include <cctype>

#include <limits>

#include <sstream>

namespace Botan {

uint16_t to_uint16(const std::string& str)

   {

   const uint32_t x = to_u32bit(str);

   if(x >> 16)

      throw Invalid_Argument("Integer value exceeds 16 bit range");

   return static_cast<uint16_t>(x);

   }

uint32_t to_u32bit(const std::string& str)

   {

   // std::stoul is not strict enough. Ensure that str is digit only [0-9]*

   for(const char chr : str)

      {

      if(chr < '0' || chr > '9')

         {

         std::string chrAsString(1, chr);

         throw Invalid_Argument("String contains non-digit char: " + chrAsString);

         }

      }

   const unsigned long int x = std::stoul(str);

   if constexpr(sizeof(unsigned long int) > 4)

      {

      // x might be uint64

      if(x > std::numeric_limits<uint32_t>::max())

         {

         throw Invalid_Argument("Integer value of " + str + " exceeds 32 bit range");

         }

      }

   return static_cast<uint32_t>(x);

   }

/*

* Parse a SCAN-style algorithm name

*/

std::vector<std::string> parse_algorithm_name(const std::string& namex)

   {

   if(namex.find('(') == std::string::npos &&

      namex.find(')') == std::string::npos)

      return std::vector<std::string>(1, namex);

   std::string name = namex, substring;

   std::vector<std::string> elems;

   size_t level = 0;

   elems.push_back(name.substr(0, name.find('(')));

   name = name.substr(name.find('('));

   for(auto i = name.begin(); i != name.end(); ++i)

      {

      char c = *i;

      if(c == '(')

         ++level;

      if(c == ')')

         {

         if(level == 1 && i == name.end() - 1)

            {

            if(elems.size() == 1)

               elems.push_back(substring.substr(1));

            else

               elems.push_back(substring);

            return elems;

            }

         if(level == 0 || (level == 1 && i != name.end() - 1))

            throw Invalid_Algorithm_Name(namex);

         --level;

         }

      if(c == ',' && level == 1)

         {

         if(elems.size() == 1)

            elems.push_back(substring.substr(1));

         else

            elems.push_back(substring);

         substring.clear();

         }

      else

         substring += c;

      }

   if(!substring.empty())

      throw Invalid_Algorithm_Name(namex);

   return elems;

   }

std::vector<std::string> split_on(const std::string& str, char delim)

   {

   std::vector<std::string> elems;

   if(str.empty()) return elems;

   std::string substr;

   for(auto i = str.begin(); i != str.end(); ++i)

      {

      if(*i == delim)

         {

         if(!substr.empty())

            elems.push_back(substr);

         substr.clear();

         }

      else

         substr += *i;

      }

   if(substr.empty())

      throw Invalid_Argument("Unable to split string: " + str);

   elems.push_back(substr);

   return elems;

   }

/*

* Join a string

*/

std::string string_join(const std::vector<std::string>& strs, char delim)

   {

   std::ostringstream out;

   for(size_t i = 0; i != strs.size(); ++i)

      {

      if(i != 0)

         out << delim;

      out << strs[i];

      }

   return out.str();

   }

/*

* Convert a decimal-dotted string to binary IP

*/

uint32_t string_to_ipv4(const std::string& str)

   {

   std::vector<std::string> parts = split_on(str, '.');

   if(parts.size() != 4)

      throw Decoding_Error("Invalid IP string " + str);

   uint32_t ip = 0;

   for(auto part = parts.begin(); part != parts.end(); ++part)

      {

      uint32_t octet = to_u32bit(*part);

      if(octet > 255)

         throw Decoding_Error("Invalid IP string " + str);

      ip = (ip << 8) | (octet & 0xFF);

      }

   return ip;

   }

/*

* Convert an IP address to decimal-dotted string

*/

std::string ipv4_to_string(uint32_t ip)

   {

   std::string str;

   uint8_t bits[4];

   store_be(ip, bits);

   for(size_t i = 0; i != 4; ++i)

      {

      if(i > 0)

         {

         str += ".";

         }

      str += std::to_string(bits[i]);

      }

   return str;

   }

std::string tolower_string(const std::string& in)

   {

   std::string s = in;

   for(size_t i = 0; i != s.size(); ++i)

      {

      const int cu = static_cast<unsigned char>(s[i]);

      if(std::isalpha(cu))

         s[i] = static_cast<char>(std::tolower(cu));

      }

   return s;

   }

bool host_wildcard_match(const std::string& issued_, const std::string& host_)

   {

   const std::string issued = tolower_string(issued_);

   const std::string host = tolower_string(host_);

   if(host.empty() || issued.empty())

      return false;

   /*

   If there are embedded nulls in your issued name

   Well I feel bad for you son

   */

   if(std::count(issued.begin(), issued.end(), char(0)) > 0)

      return false;

   // If more than one wildcard, then issued name is invalid

   const size_t stars = std::count(issued.begin(), issued.end(), '*');

   if(stars > 1)

      return false;

   // '*' is not a valid character in DNS names so should not appear on the host side

   if(std::count(host.begin(), host.end(), '*') != 0)

      return false;

   // Similarly a DNS name can't end in .

   if(host[host.size() - 1] == '.')

      return false;

   // And a host can't have an empty name component, so reject that

   if(host.find("..") != std::string::npos)

      return false;

   // Exact match: accept

   if(issued == host)

      {

      return true;

      }

   /*

   Otherwise it might be a wildcard

   If the issued size is strictly longer than the hostname size it

   couldn't possibly be a match, even if the issued value is a

   wildcard. The only exception is when the wildcard ends up empty

   (eg www.example.com matches www*.example.com)

   */

   if(issued.size() > host.size() + 1)

      {

      return false;

      }

   // If no * at all then not a wildcard, and so not a match

   if(stars != 1)

      {

      return false;

      }

   /*

   Now walk through the issued string, making sure every character

   matches. When we come to the (singular) '*', jump forward in the

   hostname by the corresponding amount. We know exactly how much

   space the wildcard takes because it must be exactly `len(host) -

   len(issued) + 1 chars`.

   We also verify that the '*' comes in the leftmost component, and

   doesn't skip over any '.' in the hostname.

   */

   size_t dots_seen = 0;

   size_t host_idx = 0;

   for(size_t i = 0; i != issued.size(); ++i)

      {

      dots_seen += (issued[i] == '.');

      if(issued[i] == '*')

         {

         // Fail: wildcard can only come in leftmost component

         if(dots_seen > 0)

            {

            return false;

            }

         /*

         Since there is only one * we know the tail of the issued and

         hostname must be an exact match. In this case advance host_idx

         to match.

         */

         const size_t advance = (host.size() - issued.size() + 1);

         if(host_idx + advance > host.size()) // shouldn't happen

            return false;

         // Can't be any intervening .s that we would have skipped

         if(std::count(host.begin() + host_idx,

                       host.begin() + host_idx + advance, '.') != 0)

            return false;

         host_idx += advance;

         }

      else

         {

         if(issued[i] != host[host_idx])

            {

            return false;

            }

         host_idx += 1;

         }

      }

   // Wildcard issued name must have at least 3 components

   if(dots_seen < 2)

      {

      return false;

      }

   return true;

   }

}