#include <tls_extensions.h>

Inheritance diagram for Botan::TLS::Server_Name_Indicator:

Public Member Functions
bool	empty () const override
std::string	host_name () const
virtual bool	is_implemented () const
std::vector< uint8_t >	serialize (Connection_Side whoami) const override
	Server_Name_Indicator (std::string_view host_name)
	Server_Name_Indicator (TLS_Data_Reader &reader, uint16_t extension_size)
Extension_Code	type () const override

Static Public Member Functions
static bool	hostname_acceptable_for_sni (std::string_view hostname)
static Extension_Code	static_type ()

Detailed Description

Server Name Indicator extension (RFC 3546)

Definition at line 103 of file tls_extensions.h.

Constructor & Destructor Documentation

◆ Server_Name_Indicator() [1/2]

Botan::TLS::Server_Name_Indicator::Server_Name_Indicator ( std::string_view host_name )

inlineexplicit

Definition at line 109 of file tls_extensions.h.

109: m_sni_host_name(host_name) {}

Botan::TLS::Server_Name_Indicator::host_name

std::string host_name() const

Definition tls_extensions.h:113

References host_name().

◆ Server_Name_Indicator() [2/2]

Botan::TLS::Server_Name_Indicator::Server_Name_Indicator	(	TLS_Data_Reader &	reader,
		uint16_t	extension_size )

Definition at line 266 of file tls_extensions.cpp.

                                                                                             {
   /*
   * This is used by the server to confirm that it knew the name
   */
   if(extension_size == 0) {
      return;
   }
 
   uint16_t name_bytes = reader.get_uint16_t();
 
   if(name_bytes + 2 != extension_size) {
      throw Decoding_Error("Bad encoding of SNI extension");
   }
 
   while(name_bytes > 0) {
      const uint8_t name_type = reader.get_byte();
      name_bytes--;
 
      if(name_type == 0) {
         // DNS
         m_sni_host_name = reader.get_string(2, 1, 65535);
         name_bytes -= static_cast<uint16_t>(2 + m_sni_host_name.size());
      } else {
         // some other unknown name type, which we will ignore
         reader.discard_next(name_bytes);
         name_bytes = 0;
      }
   }
}

References Botan::TLS::TLS_Data_Reader::discard_next(), Botan::TLS::TLS_Data_Reader::get_byte(), Botan::TLS::TLS_Data_Reader::get_string(), and Botan::TLS::TLS_Data_Reader::get_uint16_t().

Member Function Documentation

◆ empty()

bool Botan::TLS::Server_Name_Indicator::empty ( ) const

inlineoverridevirtual

Returns: if we should encode this extension or not

Implements Botan::TLS::Extension.

Definition at line 117 of file tls_extensions.h.

117{ return false; }

◆ host_name()

std::string Botan::TLS::Server_Name_Indicator::host_name ( ) const

inline

Definition at line 113 of file tls_extensions.h.

113{ return m_sni_host_name; }

Referenced by Server_Name_Indicator().

◆ hostname_acceptable_for_sni()

bool Botan::TLS::Server_Name_Indicator::hostname_acceptable_for_sni ( std::string_view hostname )

static

Definition at line 321 of file tls_extensions.cpp.

                                                                               {
   // Avoid sending an IPv4/IPv6 address in SNI as this is prohibited
 
   if(hostname.empty()) {
      return false;
   }
 
   if(string_to_ipv4(hostname).has_value()) {
      return false;
   }
 
   // IPv6? Anyway ':' is not valid in DNS
   if(hostname.find(':') != std::string_view::npos) {
      return false;
   }
 
   return true;
}

References Botan::string_to_ipv4().

Referenced by Botan::TLS::Client_Hello_12::Client_Hello_12(), Botan::TLS::Client_Hello_12::Client_Hello_12(), and Botan::TLS::Client_Hello_13::Client_Hello_13().

◆ is_implemented()

virtual bool Botan::TLS::Extension::is_implemented ( ) const

inlinevirtualinherited

Returns: true if this extension is known and implemented by Botan

Reimplemented in Botan::TLS::Unknown_Extension.

Definition at line 95 of file tls_extensions.h.

95{ return true; }

◆ serialize()

std::vector< uint8_t > Botan::TLS::Server_Name_Indicator::serialize ( Connection_Side whoami ) const

overridevirtual

Returns: serialized binary for the extension

Implements Botan::TLS::Extension.

Definition at line 296 of file tls_extensions.cpp.

                                                                                {
   // RFC 6066
   //    [...] the server SHALL include an extension of type "server_name" in
   //    the (extended) server hello. The "extension_data" field of this
   //    extension SHALL be empty.
   if(whoami == Connection_Side::Server) {
      return {};
   }
 
   std::vector<uint8_t> buf;
 
   const size_t name_len = m_sni_host_name.size();
 
   buf.push_back(get_byte<0>(static_cast<uint16_t>(name_len + 3)));
   buf.push_back(get_byte<1>(static_cast<uint16_t>(name_len + 3)));
   buf.push_back(0);  // DNS
 
   buf.push_back(get_byte<0>(static_cast<uint16_t>(name_len)));
   buf.push_back(get_byte<1>(static_cast<uint16_t>(name_len)));
 
   buf += as_span_of_bytes(m_sni_host_name);
 
   return buf;
}