lokinet/llarp/dns.hpp
2019-02-03 00:48:10 +00:00

153 lines
3.5 KiB
C++

#ifndef LLARP_DNS_HPP
#define LLARP_DNS_HPP
#include <dns.h>
#include <sys/types.h> // for uint & ssize_t
#ifndef _WIN32
#include <sys/socket.h>
#endif
#include <dns/rectypes.hpp>
#include <net/net.hpp> // for llarp::Addr , llarp::huint32_t
#include <map>
#include <string>
#include <vector>
#define LLARP_DNS_RECTYPE_A 1
#define LLARP_DNS_RECTYPE_NS 2
#define LLARP_DNS_RECTYPE_CNAME 5
#define LLARP_DNS_RECTYPE_SOA 6
#define LLARP_DNS_RECTYPE_PTR 12
#define LLARP_DNS_RECTYPE_MX 15
#define LLARP_DNS_RECTYPE_TXT 16
struct dnsc_answer_request;
struct dnsd_context;
// dnsc can work over any UDP socket
// however we can't ignore udp->user
// we need to be able to reference the request (being a request or response)
// bottom line is we can't use udp->user
// so we'll need to track all incoming and outgoing requests
struct dns_tracker
{
// uint c_responses;
uint32_t c_requests;
// request has to be a pointer
std::unordered_map< uint32_t, std::unique_ptr< dnsc_answer_request > >
client_request;
// FIXME: support multiple dns server contexts
dnsd_context *dnsd;
// rn we need 1 tracker per DNSd and each DNSd needs it's own IP
// actually we can bind once and use the tracker to sort
// but no way to tell what DNSd they want...
// std::map< llarp::Addr, std::unique_ptr< dnsc_answer_request > > dnsds;
// std::map< uint, dnsd_question_request * > daemon_request;
};
// protocol parsing/writing structures & functions
struct dns_msg_header
{
uint16_t id;
uint8_t qr : 1;
uint8_t opcode : 4;
uint8_t aa : 1;
uint8_t tc : 1;
uint8_t rd : 1;
uint8_t ra : 1;
uint8_t z : 1;
uint8_t ad : 1;
uint8_t cd : 1;
uint8_t rcode : 4;
uint16_t
fields() const
{
return (qr << 15) | (opcode << 14) | (aa << 10) | (tc << 9)
| (rd << 8) << (ra << 7) | (z << 6) | rcode;
}
uint16_t qdCount;
uint16_t anCount;
uint16_t nsCount;
uint16_t arCount;
};
struct dns_msg_question
{
std::string name;
uint16_t type;
uint16_t qClass;
};
struct dns_msg_answer
{
std::string name;
uint16_t type;
uint16_t aClass;
uint32_t ttl;
uint16_t rdLen;
std::vector< byte_t > rData;
std::unique_ptr< llarp::dns::record > record;
};
struct dns_packet
{
struct dns_msg_header header;
std::vector< std::unique_ptr< dns_msg_question > > questions;
std::vector< std::unique_ptr< dns_msg_answer > > answers;
std::vector< std::unique_ptr< dns_msg_answer > > auth_rrs;
std::vector< std::unique_ptr< dns_msg_answer > > additional_rrs;
};
std::vector< byte_t >
packet2bytes(dns_packet &in);
std::string
getDNSstring(const char *const buffer, uint32_t *pos);
void
code_domain(char *&buffer, const std::string &domain) throw();
void
vcode_domain(std::vector< byte_t > &bytes, const std::string &domain) throw();
void
vput16bits(std::vector< byte_t > &bytes, uint16_t value) throw();
void
vput32bits(std::vector< byte_t > &bytes, uint32_t value) throw();
extern "C"
{
uint16_t
get16bits(const char *&buffer) throw();
uint32_t
get32bits(const char *&buffer) throw();
bool
decode_hdr(llarp_buffer_t *buffer, dns_msg_header *hdr);
dns_msg_question *
decode_question(const char *buffer, uint32_t *pos);
dns_msg_answer *
decode_answer(const char *const buffer, uint32_t *pos);
void
put16bits(char *&buffer, uint16_t value) throw();
void
put32bits(char *&buffer, uint32_t value) throw();
void
llarp_handle_dns_recvfrom(struct llarp_udp_io *udp,
const struct sockaddr *addr, ManagedBuffer buf);
}
#endif