refactor clean up (pass 1)

pull/6/head
Ryan Tharp 6 years ago
parent a9e8584acd
commit ca06f1dded

@ -1,8 +1,9 @@
#ifndef LLARP_DNS_H_
#define LLARP_DNS_H_
#include <llarp/ev.h>
#include <llarp/ev.h> // for sockaadr
#include <sys/types.h> // for uint & ssize_t
#include <map> // for udp DNS tracker
/**
* dns.h
@ -10,53 +11,16 @@
* dns client/server
*/
#include <mutex>
typedef std::mutex mtx_t;
typedef std::lock_guard< mtx_t > lock_t;
#include <string>
struct dns_msg_header
{
uint id;
uint qr;
uint opcode;
uint aa;
uint tc;
uint rd;
uint ra;
uint rcode;
uint qdCount;
uint anCount;
uint nsCount;
uint arCount;
};
struct dns_msg_question
{
std::string name;
uint type;
uint qClass;
};
struct dns_msg_answer
{
std::string name;
uint type;
uint aClass;
u_int32_t ttl;
uint rdLen;
uint rData;
};
//#include <mutex>
//typedef std::mutex mtx_t;
//typedef std::lock_guard< mtx_t > lock_t;
// fwd declr
struct dns_query;
//struct dns_query;
struct dnsc_context;
struct dnsd_context;
struct dns_request;
struct dns_client_request;
typedef bool (*intercept_query_hook)(struct dnsc_context *, const dns_query *);
//struct dnsd_question_request;
struct dnsc_answer_request;
// dnsc can work over any UDP socket
// however we can't ignore udp->user
@ -64,128 +28,26 @@ typedef bool (*intercept_query_hook)(struct dnsc_context *, const dns_query *);
// bottom line is we can't use udp->user
// so we'll need to track all incoming and outgoing requests
#include <map>
struct dns_tracker
{
uint c_responses;
//uint c_responses;
uint c_requests;
std::map< uint, dns_client_request * > client_request;
std::map< uint, dnsc_answer_request * > client_request;
dnsd_context *dnsd;
std::map< uint, dns_request * > daemon_request;
//std::map< uint, dnsd_question_request * > daemon_request;
};
struct dnsc_context
{
/// DNS server hostname to use
// char *server;
/// DNS server port to use
// uint port;
/// Target: DNS server hostname/port to use
// FIXME: ipv6 it
sockaddr *server;
// where to create the new sockets
// struct llarp_ev_loop *netloop;
// FIXME: UDP socket pooling (or maybe at the libev level)
struct llarp_udp_io *udp;
};
struct dnsd_context
{
/// DNS daemon port to listen on
struct llarp_udp_io udp;
dnsc_context client;
/// custom data for intercept query hook
void *user;
/// hook function for intercepting dns requests
intercept_query_hook intercept;
};
/// initialize dns subsystem and bind socket
/// returns true on bind success otherwise returns false
bool
llarp_dnsc_init(struct dnsc_context *dnsc, struct llarp_udp_io *udp,
const char *dnsc_hostname, uint16_t dnsc_port);
bool
llarp_dnsc_stop(struct dnsc_context *dnsc);
bool
llarp_dnsc_unbind(struct dns_client_request *request);
bool
llarp_dnsc_bind(struct llarp_udp_io *udp, struct dns_client_request *request);
/// initialize dns subsystem and bind socket
/// returns true on bind success otherwise returns false
bool
llarp_dnsd_init(struct dnsd_context *dns, struct llarp_ev_loop *netloop,
const char *dnsd_ifname, uint16_t dnsd_port,
const char *dnsc_hostname, uint16_t dnsc_port);
#define DNC_BUF_SIZE 512
struct dns_query
{
uint16_t length;
char *url;
unsigned char request[DNC_BUF_SIZE];
uint16_t reqType;
};
struct dns_client_request;
// should we pass by llarp::Addr
// not as long as we're supporting raw
typedef void (*resolve_dns_hook_func)(dns_client_request *request);
// FIXME: separate generic from llarp
struct dns_client_request
{
/// sock type
void *sock; // pts to udp...
/// customizeable (used for outer request)
void *user;
/// storage
dns_query query;
/// hook
resolve_dns_hook_func resolved;
/// result
bool found;
struct sockaddr result;
/// Source: UDP port to use
// FIXME: separate socket for now
struct llarp_udp_io udp;
// maybe a link to dnsc_context
};
bool
llarp_dnsc_bind(struct llarp_ev_loop *netloop,
struct dns_client_request *request);
typedef void (*dnsc_answer_hook_func)(dnsc_answer_request *request);
struct sockaddr *
resolveHost(const char *url);
raw_resolve_host(const char *url);
bool
llarp_resolve_host(struct dnsc_context *dns, const char *url,
resolve_dns_hook_func resolved, void *user);
void
llarp_host_resolved(dns_client_request *request);
void
llarp_handle_recvfrom(struct llarp_udp_io *udp, const struct sockaddr *paddr,
const void *buf, ssize_t sz);
void
llarp_handle_dns_recvfrom(struct llarp_udp_io *udp,
const struct sockaddr *saddr, const void *buf,
ssize_t sz);
void
llarp_handle_recvfrom(struct llarp_udp_io *udp, const struct sockaddr *saddr,
const void *buf, ssize_t sz);
dnsc_answer_hook_func resolved, void *user);
void
raw_handle_recvfrom(int *sockfd, const struct sockaddr *saddr, const void *buf,
ssize_t sz);
llarp_host_resolved(dnsc_answer_request *request);
#endif

@ -0,0 +1,187 @@
#include "dnsd.hpp" // for llarp_handle_dnsd_recvfrom, dnsc
#include "logger.hpp"
uint16_t
get16bits(const char *&buffer) throw()
{
uint16_t value = static_cast< unsigned char >(buffer[0]);
value = value << 8;
value += static_cast< unsigned char >(buffer[1]);
buffer += 2;
return value;
}
// uint32_t
uint32_t
get32bits(const char *&buffer) throw()
{
uint32_t value = uint32_t(
(unsigned char)(buffer[0]) << 24 | (unsigned char)(buffer[1]) << 16
| (unsigned char)(buffer[2]) << 8 | (unsigned char)(buffer[3]));
buffer += 4;
return value;
}
dns_msg_header *
decode_hdr(const char *buffer)
{
dns_msg_header *hdr = new dns_msg_header;
hdr->id = get16bits(buffer);
uint fields = get16bits(buffer);
uint8_t lFields = (fields & 0x00FF) >> 0;
uint8_t hFields = (fields & 0xFF00) >> 8;
// hdr->qr = fields & 0x8000;
hdr->qr = (hFields >> 7) & 0x1;
hdr->opcode = fields & 0x7800;
hdr->aa = fields & 0x0400;
hdr->tc = fields & 0x0200;
hdr->rd = fields & 0x0100;
hdr->ra = (lFields >> 7) & 0x1;
//hdr->z = (lFields >> 6) & 0x1;
//hdr->ad = (lFields >> 5) & 0x1;
//hdr->cd = (lFields >> 4) & 0x1;
hdr->rcode = lFields & 0xf;
hdr->qdCount = get16bits(buffer);
hdr->anCount = get16bits(buffer);
hdr->nsCount = get16bits(buffer);
hdr->arCount = get16bits(buffer);
return hdr;
}
dns_msg_question *
decode_question(const char *buffer)
{
dns_msg_question *question = new dns_msg_question;
std::string m_qName = "";
int length = *buffer++;
// llarp::LogInfo("qNamLen", length);
while(length != 0)
{
for(int i = 0; i < length; i++)
{
char c = *buffer++;
m_qName.append(1, c);
}
length = *buffer++;
if(length != 0)
m_qName.append(1, '.');
}
question->name = m_qName;
question->type = get16bits(buffer);
question->qClass = get16bits(buffer);
return question;
}
dns_msg_answer *
decode_answer(const char *buffer)
{
dns_msg_answer *answer = new dns_msg_answer;
answer->type = get16bits(buffer);
//assert(answer->type < 259);
if (answer->type > 259)
{
llarp::LogWarn("Answer type is off the charts");
}
answer->aClass = get16bits(buffer);
answer->ttl = get32bits(buffer);
answer->rdLen = get16bits(buffer);
if (answer->rdLen == 4)
{
answer->rData = new uint8_t[answer->rdLen];
memcpy(answer->rData, buffer, answer->rdLen);
}
else
{
llarp::LogWarn("Unknown Type ", answer->type);
}
return answer;
}
void
put16bits(char *&buffer, uint16_t value) throw()
{
buffer[0] = (value & 0xFF00) >> 8;
buffer[1] = value & 0xFF;
buffer += 2;
}
void
put32bits(char *&buffer, uint32_t value) throw()
{
buffer[0] = (value & 0xFF000000) >> 24;
buffer[1] = (value & 0x00FF0000) >> 16;
buffer[2] = (value & 0x0000FF00) >> 8;
buffer[3] = (value & 0x000000FF) >> 0;
buffer += 4;
}
void
code_domain(char *&buffer, const std::string &domain) throw()
{
int start(0), end; // indexes
// llarp::LogInfo("domain [", domain, "]");
while((end = domain.find('.', start)) != std::string::npos)
{
*buffer++ = end - start; // label length octet
for(int i = start; i < end; i++)
{
*buffer++ = domain[i]; // label octets
// llarp::LogInfo("Writing ", domain[i], " at ", i);
}
start = end + 1; // Skip '.'
}
// llarp::LogInfo("start ", start, " domain size ", domain.size());
*buffer++ = domain.size() - start; // last label length octet
for(int i = start; i < domain.size(); i++)
{
*buffer++ = domain[i]; // last label octets
// llarp::LogInfo("Writing ", domain[i], " at ", i);
}
*buffer++ = 0;
}
void
llarp_handle_dns_recvfrom(struct llarp_udp_io *udp,
const struct sockaddr *saddr, const void *buf,
ssize_t sz)
{
unsigned char *castBuf = (unsigned char *)buf;
// auto buffer = llarp::StackBuffer< decltype(castBuf) >(castBuf);
dns_msg_header *hdr = decode_hdr((const char *)castBuf);
// castBuf += 12;
llarp::LogInfo("msg id ", hdr->id);
llarp::LogInfo("msg qr ", (uint8_t)hdr->qr);
if(hdr->qr)
{
llarp::LogInfo("handling as dnsc answer");
llarp_handle_dnsc_recvfrom(udp, saddr, buf, sz);
}
else
{
llarp::LogInfo("handling as dnsd question");
llarp_handle_dnsd_recvfrom(udp, saddr, buf, sz);
}
/*
llarp::LogInfo("msg op ", hdr->opcode);
llarp::LogInfo("msg rc ", hdr->rcode);
for(uint i = 0; i < hdr->qdCount; i++)
{
dns_msg_question *question = decode_question((const char*)castBuf);
llarp::LogInfo("Read a question");
castBuf += question->name.length() + 8;
}
for(uint i = 0; i < hdr->anCount; i++)
{
dns_msg_answer *answer = decode_answer((const char*)castBuf);
llarp::LogInfo("Read an answer");
castBuf += answer->name.length() + 4 + 4 + 4 + answer->rdLen;
}
*/
}

@ -0,0 +1,75 @@
#ifndef LIBLLARP_DNS_HPP
#define LIBLLARP_DNS_HPP
#include <string>
#include <sys/types.h> // for uint & ssize_t
// 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 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;
uint8_t *rData;
};
uint16_t
get16bits(const char *&buffer) throw();
uint32_t
get32bits(const char *&buffer) throw();
dns_msg_header *
decode_hdr(const char *buffer);
dns_msg_question *
decode_question(const char *buffer);
dns_msg_answer *
decode_answer(const char *buffer);
void
put16bits(char *&buffer, uint16_t value) throw();
void
put32bits(char *&buffer, uint32_t value) throw();
void
code_domain(char *&buffer, const std::string &domain) throw();
void
llarp_handle_dns_recvfrom(struct llarp_udp_io *udp,
const struct sockaddr *saddr, const void *buf,
ssize_t sz);
#endif

@ -1,6 +1,6 @@
// why dnsd? what do you need from that?
#include "dnsc.hpp"
#include <llarp/dns.h>
#include "buffer.hpp"
#include "dnsd.hpp"
#include <netdb.h> /* getaddrinfo, getnameinfo */
#include <stdlib.h> /* exit */
@ -20,14 +20,80 @@
#define SERVER "8.8.8.8"
#define PORT 53
mtx_t m_dnsc_Mutex;
mtx_t m_dnsc2_Mutex;
#define DNC_BUF_SIZE 512
// a question to be asked remotely
// header, question
struct dns_query
{
uint16_t length;
//char *url;
unsigned char request[DNC_BUF_SIZE];
//uint16_t reqType;
};
struct dns_query*
build_dns_packet(char *url, uint16_t id, uint16_t reqType)
{
dns_query *dnsQuery = new dns_query;
dnsQuery->length = 12;
// ID
// buffer[0] = (value & 0xFF00) >> 8;
// buffer[1] = value & 0xFF;
llarp::LogInfo("building request ", id);
dnsQuery->request[0] = (id & 0xFF00) >> 8;
dnsQuery->request[1] = (id & 0x00FF) >> 0;
// field
dnsQuery->request[2] = 0x01;
dnsQuery->request[3] = 0x00;
// questions
dnsQuery->request[4] = 0x00;
dnsQuery->request[5] = 0x01;
// answers
dnsQuery->request[6] = 0x00;
dnsQuery->request[7] = 0x00;
// ns
dnsQuery->request[8] = 0x00;
dnsQuery->request[9] = 0x00;
// ar
dnsQuery->request[10] = 0x00;
dnsQuery->request[11] = 0x00;
char *word;
// llarp::LogDebug("Asking DNS server %s about %s", SERVER, dnsQuery->url);
char *strTemp = strdup(url);
word = strtok(strTemp, ".");
while(word)
{
// llarp::LogDebug("parsing hostname: \"%s\" is %zu characters", word,
// strlen(word));
dnsQuery->request[dnsQuery->length++] = strlen(word);
for(unsigned int i = 0; i < strlen(word); i++)
{
dnsQuery->request[dnsQuery->length++] = word[i];
}
word = strtok(NULL, ".");
}
dnsQuery->request[dnsQuery->length++] = 0x00; // End of the host name
dnsQuery->request[dnsQuery->length++] =
0x00; // 0x0001 - Query is a Type A query (host address)
dnsQuery->request[dnsQuery->length++] = reqType;
dnsQuery->request[dnsQuery->length++] =
0x00; // 0x0001 - Query is class IN (Internet address)
dnsQuery->request[dnsQuery->length++] = 0x01;
return dnsQuery;
}
struct sockaddr *
resolveHost(const char *url)
raw_resolve_host(const char *url)
{
char *sUrl = strdup(url);
struct dns_query dnsQuery;
//char *sUrl = strdup(url);
//struct dns_query dnsQuery;
dns_query *dns_packet = build_dns_packet((char *)url, 0xDB42, 1);
/*
dnsQuery.length = 12;
dnsQuery.url = sUrl;
dnsQuery.reqType = 0x01;
@ -45,12 +111,13 @@ resolveHost(const char *url)
dnsQuery.request[9] = 0x00;
dnsQuery.request[10] = 0x00;
dnsQuery.request[11] = 0x00;
*/
char *word;
unsigned int i;
llarp::LogDebug("Asking DNS server ", SERVER, " about ", url);
// dnsQuery.reqType = 0x01;
/*
word = strtok(sUrl, ".");
while(word)
{
@ -71,7 +138,8 @@ resolveHost(const char *url)
dnsQuery.request[dnsQuery.length++] =
0x00; // 0x0001 - Query is class IN (Internet address)
dnsQuery.request[dnsQuery.length++] = 0x01;
*/
struct sockaddr_in addr;
// int socket;
ssize_t ret;
@ -109,8 +177,9 @@ resolveHost(const char *url)
size = sizeof(addr);
// hexdump("sending packet", &dnsQuery.request, dnsQuery.length);
ret = sendto(sockfd, dnsQuery.request, dnsQuery.length, 0,
ret = sendto(sockfd, dns_packet->request, dns_packet->length, 0,
(struct sockaddr *)&addr, size);
delete dns_packet;
if(ret < 0)
{
llarp::LogWarn("Error Sending Request");
@ -148,7 +217,8 @@ resolveHost(const char *url)
llarp::LogDebug("name server resource record count: %u\n", NSCOUNT);
ARCOUNT = (uint16_t)buffer[10] * 0x100 + buffer[11];
llarp::LogDebug("additional records count: %u\n", ARCOUNT);
/*
llarp::LogDebug("query type: %u\n", dnsQuery.reqType);
QCLASS = (uint16_t)dnsQuery.request[dnsQuery.length - 2] * 0x100
+ dnsQuery.request[dnsQuery.length - 1];
@ -165,6 +235,7 @@ resolveHost(const char *url)
llarp::LogDebug("bytes in answer: %u\n", RDLENGTH);
MSGID = (uint16_t)buffer[0] * 0x100 + buffer[1];
llarp::LogDebug("answer msg id: %u\n", MSGID);
*/
if(rcode == 2)
{
@ -176,15 +247,15 @@ resolveHost(const char *url)
}
else if(rcode == 3)
{
llarp::LogWarn("nameserver %s returned NXDOMAIN for %s:\n", SERVER,
dnsQuery.url);
llarp::LogWarn("nameserver %s returned NXDOMAIN for ", SERVER);
llarp::LogWarn(
" the domain name referenced in the query does not exist\n");
return nullptr;
}
/* search for and print IPv4 addresses */
if(dnsQuery.reqType == 0x01)
//if(dnsQuery.reqType == 0x01)
if (1)
{
llarp::LogDebug("DNS server's answer is: (type#=%u):", ATYPE);
// printf("IPv4 address(es) for %s:\n", dnsQuery.url);
@ -224,11 +295,11 @@ resolveHost(const char *url)
}
void
llarp_handle_dnsclient_recvfrom(struct llarp_udp_io *udp,
llarp_handle_dnsc_recvfrom(struct llarp_udp_io *udp,
const struct sockaddr *saddr, const void *buf,
ssize_t sz)
{
lock_t lock(m_dnsc_Mutex);
//lock_t lock(m_dnsc_Mutex);
// llarp::LogInfo("got a response, udp user is ", udp->user);
unsigned char *castBuf = (unsigned char *)buf;
@ -239,12 +310,12 @@ llarp_handle_dnsclient_recvfrom(struct llarp_udp_io *udp,
// if we sent this out, then there's an id
struct dns_tracker *tracker = (struct dns_tracker *)udp->user;
struct dns_client_request *request = tracker->client_request[hdr->id];
struct dnsc_answer_request *request = tracker->client_request[hdr->id];
if(!request)
{
llarp::LogError(
"User data to DNS Client response not a dns_client_request");
"User data to DNS Client response not a dnsc_answer_request");
// we can't call back the hook
return;
}
@ -261,7 +332,7 @@ llarp_handle_dnsclient_recvfrom(struct llarp_udp_io *udp,
// auto buffer = llarp::StackBuffer< decltype(castBuf) >(castBuf);
// hexdump("received packet", &buffer, ret);
/*
uint16_t QDCOUNT; // No. of items in Question Section
uint16_t ANCOUNT; // No. of items in Answer Section
uint16_t NSCOUNT; // No. of items in Authority Section
@ -272,36 +343,24 @@ llarp_handle_dnsclient_recvfrom(struct llarp_udp_io *udp,
uint32_t TTL; // The number of seconds the results can be cached
uint16_t RDLENGTH; // The length of the RDATA field
uint16_t MSGID;
int rcode;
int length;
*/
uint8_t rcode;
//int length;
struct dns_query *dnsQuery = &request->query;
//struct dns_query *dnsQuery = &request->query;
rcode = (buffer[3] & 0x0F);
llarp::LogInfo("dnsc rcode ", rcode);
//rcode = (buffer[3] & 0x0F);
//llarp::LogInfo("dnsc rcode ", rcode);
dns_msg_header *msg = decode_hdr((const char *)castBuf);
castBuf += 12;
llarp::LogInfo("msg id ", msg->id);
llarp::LogInfo("msg qr ", msg->qr);
llarp::LogInfo("msg op ", msg->opcode);
llarp::LogInfo("msg rc ", msg->rcode);
// tempBuf[0] = buffer[4];
// tempBuf[1] = buffer[5];
// tempBuf[2] = '\0';
// printf("%0x %0x %0x %0x\n", buffer[4], buffer[5], tempBuf[0], tempBuf[1]);
// QDCOUNT = (uint16_t) strtol(tempBuf, NULL, 16);
QDCOUNT = (uint16_t)buffer[4] * 0x100 + buffer[5];
llarp::LogInfo("entries in question section: ", QDCOUNT);
ANCOUNT = (uint16_t)buffer[6] * 0x100 + buffer[7];
llarp::LogInfo("records in answer section: ", ANCOUNT);
NSCOUNT = (uint16_t)buffer[8] * 0x100 + buffer[9];
llarp::LogInfo("name server resource record count: ", NSCOUNT);
ARCOUNT = (uint16_t)buffer[10] * 0x100 + buffer[11];
llarp::LogInfo("additional records count: ", ARCOUNT);
uint8_t qr = msg->qr;
llarp::LogInfo("msg qr ", qr);
uint8_t opcode = msg->opcode;
llarp::LogInfo("msg op ", opcode);
rcode = msg->rcode;
llarp::LogInfo("msg rc ", rcode);
llarp::LogInfo("msg qdc ", msg->qdCount);
llarp::LogInfo("msg anc ", msg->anCount);
@ -309,18 +368,48 @@ llarp_handle_dnsclient_recvfrom(struct llarp_udp_io *udp,
llarp::LogInfo("msg arc ", msg->arCount);
// we may need to parse question first
/*
dns_msg_question *question = decode_question((const char *)castBuf);
llarp::LogInfo("que name ", question->name);
castBuf += question->name.length() + 8;
dns_msg_answer *answer = decode_answer((const char *)castBuf);
castBuf += answer->name.length() + 4 + 4 + 4 + answer->rdLen;
*/
// FIXME: only handling one atm
dns_msg_question *question = nullptr;
for(uint i = 0; i < hdr->qdCount; i++)
{
question = decode_question((const char*)castBuf);
llarp::LogInfo("Read a question");
castBuf += question->name.length() + 8;
}
// FIXME: only handling one atm
dns_msg_answer *answer = nullptr;
for(uint i = 0; i < hdr->anCount; i++)
{
answer = decode_answer((const char*)castBuf);
llarp::LogInfo("Read an answer");
castBuf += answer->name.length() + 4 + 4 + 4 + answer->rdLen;
}
// handle authority records (usually no answers with these, so we'll just stomp)
// usually NS records tho
for(uint i = 0; i < hdr->nsCount; i++)
{
answer = decode_answer((const char*)castBuf);
llarp::LogInfo("Read an authority");
castBuf += answer->name.length() + 4 + 4 + 4 + answer->rdLen;
}
// dns_msg_answer *answer2 = decode_answer((const char*)castBuf);
// castBuf += answer->name.length() + 4 + 4 + 4 + answer->rdLen;
// llarp::LogDebug("query type: %u\n", dnsQuery->reqType);
/*
QCLASS = (uint16_t)dnsQuery->request[dnsQuery->length - 2] * 0x100
+ dnsQuery->request[dnsQuery->length - 1];
llarp::LogInfo("query class: ", QCLASS);
@ -339,7 +428,15 @@ llarp_handle_dnsclient_recvfrom(struct llarp_udp_io *udp,
MSGID = (uint16_t)buffer[0] * 0x100 + buffer[1];
// llarp::LogDebug("answer msg id: %u\n", MSGID);
*/
if(answer == nullptr)
{
llarp::LogWarn("nameserver ", SERVER, " didnt return any answers:");
request->resolved(request);
return;
}
llarp::LogInfo("ans class ", answer->aClass);
llarp::LogInfo("ans type ", answer->type);
llarp::LogInfo("ans ttl ", answer->ttl);
@ -364,7 +461,7 @@ llarp_handle_dnsclient_recvfrom(struct llarp_udp_io *udp,
else if(rcode == 3)
{
llarp::LogWarn("nameserver ", SERVER,
" returned NXDOMAIN for: ", dnsQuery->url);
" returned NXDOMAIN for: ", request->question.name);
llarp::LogWarn(" the domain name referenced in the query does not exist");
request->resolved(request);
return;
@ -373,187 +470,100 @@ llarp_handle_dnsclient_recvfrom(struct llarp_udp_io *udp,
int ip = 0;
/* search for and print IPv4 addresses */
if(dnsQuery->reqType == 0x01)
//if(dnsQuery->reqType == 0x01)
if(request->question.type == 1)
{
llarp::LogInfo("DNS server's answer is: (type#=", ATYPE, "):");
llarp::LogInfo("IPv4 address(es) for ", dnsQuery->url, ":");
for(unsigned int i = 0; i < sz; i++)
//llarp::LogInfo("DNS server's answer is: (type#=", ATYPE, "):");
llarp::LogInfo("IPv4 address(es) for ", request->question.name, ":");
if (answer->rdLen == 4)
{
if(buffer[i] == 0xC0 && buffer[i + 3] == 0x01)
{
ip++;
i += 12; /* ! += buf[i+1]; */
// llarp::LogInfo(" %u.%u.%u.%u\n", buffer[i], buffer[i+1], buffer[i+2],
// buffer[i+3]);
/*
struct sockaddr *g_addr = new sockaddr;
g_addr->sa_family = AF_INET;
g_addr->sa_len = sizeof(in_addr);
struct in_addr *addr = &((struct sockaddr_in *)g_addr)->sin_addr;
*/
unsigned char *ip;
// have ip point to s_addr
request->result.sa_family = AF_INET;
request->result.sa_len = sizeof(in_addr);
struct in_addr *addr =
&((struct sockaddr_in *)&request->result)->sin_addr;
// ip = (unsigned char *) &request->result.sa_data;
ip = (unsigned char *)&(addr->s_addr);
ip[0] = buffer[i + 0];
ip[1] = buffer[i + 1];
ip[2] = buffer[i + 2];
ip[3] = buffer[i + 3];
llarp::Addr test(request->result);
llarp::LogInfo(test);
// return g_addr;
// request->result = g_addr;
request->found = true;
request->resolved(request);
return;
}
request->result.sa_family = AF_INET;
request->result.sa_len = sizeof(in_addr);
struct in_addr *addr =
&((struct sockaddr_in *)&request->result)->sin_addr;
unsigned char *ip = (unsigned char *)&(addr->s_addr);
ip[0] = answer->rData[0];
ip[1] = answer->rData[1];
ip[2] = answer->rData[2];
ip[3] = answer->rData[3];
llarp::Addr test(request->result);
llarp::LogInfo(test);
request->found = true;
request->resolved(request);
return;
}
if(!ip)
{
llarp::LogWarn(" No IPv4 address found in the DNS response!");
llarp::LogWarn(" No IPv4 address found in the DNS answer!");
request->resolved(request);
return;
}
}
}
void
llarp_handle_dns_recvfrom(struct llarp_udp_io *udp,
const struct sockaddr *saddr, const void *buf,
ssize_t sz)
{
unsigned char *castBuf = (unsigned char *)buf;
// auto buffer = llarp::StackBuffer< decltype(castBuf) >(castBuf);
dns_msg_header *hdr = decode_hdr((const char *)castBuf);
// castBuf += 12;
llarp::LogInfo("msg id ", hdr->id);
llarp::LogInfo("msg qr ", hdr->qr);
if(hdr->qr)
{
llarp_handle_dnsclient_recvfrom(udp, saddr, buf, sz);
}
else
{
llarp_handle_recvfrom(udp, saddr, buf, sz);
}
/*
llarp::LogInfo("msg op ", hdr->opcode);
llarp::LogInfo("msg rc ", hdr->rcode);
for(uint i = 0; i < hdr->qdCount; i++)
{
dns_msg_question *question = decode_question((const char*)castBuf);
llarp::LogInfo("Read a question");
castBuf += question->name.length() + 8;
}
for(uint i = 0; i < hdr->anCount; i++)
{
dns_msg_answer *answer = decode_answer((const char*)castBuf);
llarp::LogInfo("Read an answer");
castBuf += answer->name.length() + 4 + 4 + 4 + answer->rdLen;
}
*/
}
void
build_dns_query(struct dns_query *dnsQuery, uint id)
{
dnsQuery->length = 12;
dnsQuery->reqType = 0x01;
// ID
// buffer[0] = (value & 0xFF00) >> 8;
// buffer[1] = value & 0xFF;
llarp::LogInfo("building request ", id);
dnsQuery->request[0] = (id & 0xFF00) >> 8;
dnsQuery->request[1] = (id & 0x00FF) >> 0;
// field
dnsQuery->request[2] = 0x01;
dnsQuery->request[3] = 0x00;
// questions
dnsQuery->request[4] = 0x00;
dnsQuery->request[5] = 0x01;
// answers
dnsQuery->request[6] = 0x00;
dnsQuery->request[7] = 0x00;
// ns
dnsQuery->request[8] = 0x00;
dnsQuery->request[9] = 0x00;
// ar
dnsQuery->request[10] = 0x00;
dnsQuery->request[11] = 0x00;
char *word;
// llarp::LogDebug("Asking DNS server %s about %s", SERVER, dnsQuery->url);
char *strTemp = strdup(dnsQuery->url);
word = strtok(strTemp, ".");
while(word)
{
// llarp::LogDebug("parsing hostname: \"%s\" is %zu characters", word,
// strlen(word));
dnsQuery->request[dnsQuery->length++] = strlen(word);
for(unsigned int i = 0; i < strlen(word); i++)
{
dnsQuery->request[dnsQuery->length++] = word[i];
}
word = strtok(NULL, ".");
}
dnsQuery->request[dnsQuery->length++] = 0x00; // End of the host name
dnsQuery->request[dnsQuery->length++] =
0x00; // 0x0001 - Query is a Type A query (host address)
dnsQuery->request[dnsQuery->length++] = dnsQuery->reqType;
dnsQuery->request[dnsQuery->length++] =
0x00; // 0x0001 - Query is class IN (Internet address)
dnsQuery->request[dnsQuery->length++] = 0x01;
}
bool
llarp_resolve_host(struct dnsc_context *dnsc, const char *url,
resolve_dns_hook_func resolved, void *user)
dnsc_answer_hook_func resolved, void *user)
{
dns_client_request *request = new dns_client_request;
request->sock = (void *)&request->udp;
request->user = user;
// configure query
request->query.url = strdup(url);
request->resolved = resolved;
request->found = false;
// request address holds through the packet recv
// request->udp.user = request;
// finish setting up our query
struct dns_query *dnsQuery = &request->query;
dnsc_answer_request *request = new dnsc_answer_request;
request->sock = (void *)&dnsc->udp;
request->user = user;
request->resolved = resolved;
request->found = false;
request->context = dnsc;
char *sUrl = strdup(url);
request->question.name = sUrl;
request->question.type = 1;
request->question.qClass = 1;
// register request with udp response tracker
dns_tracker *tracker = (dns_tracker *)dnsc->udp->user;
build_dns_query(dnsQuery, ++tracker->c_requests);
// build a socket per request because we're multithreaded and will have many
// inflight
/*
if (!llarp_dnsc_bind(dnsc->netloop, request))
{
llarp::LogWarn("Error binding");
return false;
}
uint16_t length = 0;
dns_msg_header header;
header.id = htons(id);
header.qr = 0;
header.opcode = 0;
header.aa = 0;
header.tc = 0;
header.rd = 1;
header.ra = 0;
header.rcode = 0;
header.qdCount = htons(1);
header.anCount = 0;
header.nsCount = 0;
header.arCount = 0;
length += 12;
//request->question.name = sUrl;
request->question.type = htons(1);
request->question.qClass = htons(1);
uint16_t qLen = request->question.name.length() + 8;
length += qLen;
unsigned char bytes[length];
// memcpy isn't going to fix the network endian issue
// encode header into bytes
memcpy(bytes, &header, 12);
// encode question into bytes
memcpy(bytes + 12, &request->question, qLen);
*/
tracker->client_request[tracker->c_requests] = request;
ssize_t ret = llarp_ev_udp_sendto(dnsc->udp, dnsc->server, dnsQuery->request,
dnsQuery->length);
uint16_t id = ++tracker->c_requests;
tracker->client_request[id] = request;
//llarp::LogInfo("Sending request #", tracker->c_requests, " ", length, " bytes");
dns_query *dns_packet = build_dns_packet((char *)url, id, 1);
//ssize_t ret = llarp_ev_udp_sendto(dnsc->udp, dnsc->server, bytes, length);
ssize_t ret = llarp_ev_udp_sendto(dnsc->udp, dnsc->server, dns_packet->request, dns_packet->length);
delete dns_packet;
if(ret < 0)
{
llarp::LogWarn("Error Sending Request");
@ -564,42 +574,11 @@ llarp_resolve_host(struct dnsc_context *dnsc, const char *url,
}
void
llarp_host_resolved(dns_client_request *request)
llarp_host_resolved(dnsc_answer_request *request)
{
delete request;
}
bool
llarp_dnsc_bind(struct llarp_ev_loop *netloop,
struct dns_client_request *request)
{
lock_t lock(m_dnsc2_Mutex);
// just grab a random open port
struct sockaddr_in srcaddr;
srcaddr.sin_addr.s_addr = inet_addr("0.0.0.0");
srcaddr.sin_family = AF_INET;
// we'll need to make sure the port is >1024 if not root
// llarp::LogInfo("outgoing port check ", ntohs(srcaddr.sin_port));
if(ntohs(srcaddr.sin_port) < 1024)
srcaddr.sin_port = htons(ntohs(srcaddr.sin_port) + 1024);
request->udp.user = request;
request->udp.recvfrom = &llarp_handle_dns_recvfrom;
request->udp.tick = nullptr;
// create new listener for this request
return llarp_ev_add_udp(netloop, &request->udp, (const sockaddr *)&srcaddr)
!= -1;
}
// FIXME: drop the bool
bool
llarp_dnsc_unbind(struct dns_client_request *request)
{
llarp_ev_close_udp(&request->udp); // stop listening
return true;
}
bool
llarp_dnsc_init(struct dnsc_context *dnsc, struct llarp_udp_io *udp,
const char *dnsc_hostname, uint16_t dnsc_port)
@ -616,7 +595,6 @@ llarp_dnsc_init(struct dnsc_context *dnsc, struct llarp_udp_io *udp,
bool
llarp_dnsc_stop(struct dnsc_context *dnsc)
{
// llarp_ev_close_udp(&dnsc->udp); // stop listening
delete(sockaddr_in *)dnsc->server; // deallocation
return true;
}

@ -1,6 +1,61 @@
#ifndef LIBLLARP_DNSC_HPP
#define LIBLLARP_DNSC_HPP
#include <llarp/dns.h>
#include <llarp/ev.h> // for sockaadr
#include "dns.hpp" // get protocol structs
// internal, non-public functions
// well dnsc init/stop are public...
struct dnsc_answer_request;
// should we pass by llarp::Addr
// not as long as we're supporting raw
typedef void (*dnsc_answer_hook_func)(dnsc_answer_request *request);
// FIXME: separate generic from llarp
struct dnsc_answer_request
{
/// sock type
void *sock; // pts to udp...
/// customizable (used for hook (outer request))
void *user;
/// storage
dns_msg_question question;
/// hook
dnsc_answer_hook_func resolved;
/// result
bool found;
struct sockaddr result;
// a reference to dnsc_context incase of multiple contexts
struct dnsc_context *context;
};
void
llarp_handle_dnsc_recvfrom(struct llarp_udp_io *udp,
const struct sockaddr *saddr, const void *buf,
ssize_t sz);
void
raw_handle_recvfrom(int *sockfd, const struct sockaddr *saddr, const void *buf,
ssize_t sz);
struct dnsc_context
{
/// Target: DNS server hostname/port to use
// FIXME: ipv6 it
sockaddr *server;
// where to create the new sockets
struct llarp_udp_io *udp;
};
/// initialize dns subsystem and bind socket
/// returns true on bind success otherwise returns false
bool
llarp_dnsc_init(struct dnsc_context *dnsc, struct llarp_udp_io *udp,
const char *dnsc_hostname, uint16_t dnsc_port);
bool
llarp_dnsc_stop(struct dnsc_context *dnsc);
#endif

@ -1,139 +1,10 @@
#include "dnsd.hpp"
#include <llarp/dns.h>
#include <string>
#include "ev.hpp"
#include "logger.hpp"
#include "net.hpp"
mtx_t m_dnsd_Mutex;
mtx_t m_dnsd2_Mutex;
mtx_t m_dnsd3_Mutex;
int
get16bits(const char *&buffer) throw()
{
int value = static_cast< unsigned char >(buffer[0]);
value = value << 8;
value += static_cast< unsigned char >(buffer[1]);
buffer += 2;
return value;
}
// uint32_t
uint32_t
get32bits(const char *&buffer) throw()
{
uint32_t value = uint32_t(
(unsigned char)(buffer[0]) << 24 | (unsigned char)(buffer[1]) << 16
| (unsigned char)(buffer[2]) << 8 | (unsigned char)(buffer[3]));
buffer += 4;
return value;
}
void
put16bits(char *&buffer, uint value) throw()
{
buffer[0] = (value & 0xFF00) >> 8;
buffer[1] = value & 0xFF;
buffer += 2;
}
void
put32bits(char *&buffer, unsigned long value) throw()
{
buffer[0] = (value & 0xFF000000) >> 24;
buffer[1] = (value & 0x00FF0000) >> 16;
buffer[2] = (value & 0x0000FF00) >> 8;
buffer[3] = (value & 0x000000FF) >> 0;
buffer += 4;
}
dns_msg_header *
decode_hdr(const char *buffer)
{
dns_msg_header *hdr = new dns_msg_header;
hdr->id = get16bits(buffer);
uint fields = get16bits(buffer);
// hdr->qr = fields & 0x8000;
hdr->qr = (fields >> 7) & 0x1;
hdr->opcode = fields & 0x7800;
hdr->aa = fields & 0x0400;
hdr->tc = fields & 0x0200;
hdr->rd = fields & 0x0100;
hdr->ra = fields & 0x8000;
// z, ad, cd
hdr->rcode = (buffer[3] & 0x0F);
hdr->qdCount = get16bits(buffer);
hdr->anCount = get16bits(buffer);
hdr->nsCount = get16bits(buffer);
hdr->arCount = get16bits(buffer);
return hdr;
}
dns_msg_question *
decode_question(const char *buffer)
{
dns_msg_question *question = new dns_msg_question;
std::string m_qName = "";
int length = *buffer++;
// llarp::LogInfo("qNamLen", length);
while(length != 0)
{
for(int i = 0; i < length; i++)
{
char c = *buffer++;
m_qName.append(1, c);
}
length = *buffer++;
if(length != 0)
m_qName.append(1, '.');
}
question->name = m_qName;
question->type = get16bits(buffer);
question->qClass = get16bits(buffer);
return question;
}
dns_msg_answer *
decode_answer(const char *buffer)
{
dns_msg_answer *answer = new dns_msg_answer;
answer->type = get16bits(buffer);
answer->aClass = get16bits(buffer);
answer->ttl = get32bits(buffer);
answer->rdLen = get16bits(buffer);
answer->rData = get16bits(buffer);
return answer;
}
void
code_domain(char *&buffer, const std::string &domain) throw()
{
int start(0), end; // indexes
// llarp::LogInfo("domain [", domain, "]");
while((end = domain.find('.', start)) != std::string::npos)
{
*buffer++ = end - start; // label length octet
for(int i = start; i < end; i++)
{
*buffer++ = domain[i]; // label octets
// llarp::LogInfo("Writing ", domain[i], " at ", i);
}
start = end + 1; // Skip '.'
}
// llarp::LogInfo("start ", start, " domain size ", domain.size());
*buffer++ = domain.size() - start; // last label length octet
for(int i = start; i < domain.size(); i++)
{
*buffer++ = domain[i]; // last label octets
// llarp::LogInfo("Writing ", domain[i], " at ", i);
}
*buffer++ = 0;
}
ssize_t
raw_sendto_dns_hook_func(void *sock, const struct sockaddr *from,
const void *buffer, size_t length)
@ -168,11 +39,13 @@ forward_dns_request(std::string request)
return true;
}
// FIXME: we need an DNS answer not a sockaddr
// otherwise ttl, type and class can't be relayed correctly
void
writesend_dnss_response(struct sockaddr *hostRes, const struct sockaddr *from,
dns_request *request)
dnsd_question_request *request)
{
lock_t lock(m_dnsd2_Mutex);
//lock_t lock(m_dnsd2_Mutex);
if(!hostRes)
{
llarp::LogWarn("Failed to resolve");
@ -198,15 +71,15 @@ writesend_dnss_response(struct sockaddr *hostRes, const struct sockaddr *from,
put16bits(write_buffer, 0); // AR (number of Additional RRs)
// code question
code_domain(write_buffer, request->m_qName);
put16bits(write_buffer, request->m_qType);
put16bits(write_buffer, request->m_qClass);
code_domain(write_buffer, request->question.name);
put16bits(write_buffer, request->question.type);
put16bits(write_buffer, request->question.qClass);
// code answer
code_domain(write_buffer, request->m_qName); // com, type=6, ttl=0
put16bits(write_buffer, request->m_qType);
put16bits(write_buffer, request->m_qClass);
put32bits(write_buffer, 1453); // ttl
code_domain(write_buffer, request->question.name); // com, type=6, ttl=0
put16bits(write_buffer, request->question.type);
put16bits(write_buffer, request->question.qClass);
put32bits(write_buffer, 1); // ttl
// has to be a string of 4 bytes
struct sockaddr_in *sin = (struct sockaddr_in *)hostRes;
@ -225,12 +98,12 @@ writesend_dnss_response(struct sockaddr *hostRes, const struct sockaddr *from,
}
void
handle_dnsc_result(dns_client_request *client_request)
handle_dnsc_result(dnsc_answer_request *client_request)
{
// llarp::LogInfo("phase2 client ", client_request);
// writesend_dnss_response(struct sockaddr *hostRes, const struct sockaddr
// *from, dns_request *request)
dns_request *server_request = (dns_request *)client_request->user;
// *from, dnsd_question_request *request)
dnsd_question_request *server_request = (dnsd_question_request *)client_request->user;
// llarp::Addr test(*server_request->from);
// llarp::LogInfo("server request sock ", server_request->from, " is ", test);
// llarp::LogInfo("phase2 server ", server_request);
@ -243,9 +116,9 @@ handle_dnsc_result(dns_client_request *client_request)
// our generic version
void
handle_recvfrom(const char *buffer, ssize_t nbytes, const struct sockaddr *from,
dns_request *request)
dnsd_question_request *request)
{
lock_t lock(m_dnsd_Mutex);
//lock_t lock(m_dnsd_Mutex);
const size_t HDR_OFFSET = 12;
const char *p_buffer = buffer;
@ -270,12 +143,16 @@ handle_recvfrom(const char *buffer, ssize_t nbytes, const struct sockaddr *from,
if(length != 0)
m_qName.append(1, '.');
}
request->m_qName = m_qName;
request->m_qType = get16bits(p_buffer);
request->m_qClass = get16bits(p_buffer);
llarp::LogInfo("qName ", m_qName);
llarp::LogInfo("qType ", request->m_qType);
llarp::LogInfo("qClass ", request->m_qClass);
request->question.name = m_qName;
request->question.type = get16bits(p_buffer);
request->question.qClass = get16bits(p_buffer);
//request->m_qName = m_qName;
//request->m_qType = request->question.type;
//request->m_qClass = request->question.qClass;
llarp::LogInfo("qName ", request->question.name);
llarp::LogInfo("qType ", request->question.type);
llarp::LogInfo("qClass ", request->question.qClass);
/*
llarp::Addr test(*request->from);
@ -291,20 +168,7 @@ handle_recvfrom(const char *buffer, ssize_t nbytes, const struct sockaddr *from,
}
sockaddr *hostRes = nullptr;
// FIXME: how can we tell the mode?
// struct llarp_udp_io *udp = static_cast<struct llarp_udp_io
// *>(request->user);
if(0)
{
hostRes = resolveHost(m_qName.c_str());
llarp::Addr anIp(*hostRes);
llarp::LogInfo("DNS got ", anIp);
// writesend_dnss_response(struct sockaddr *hostRes, const struct sockaddr
// *from, dns_request *request)
sockaddr *fromCopy = new sockaddr(*from);
writesend_dnss_response(hostRes, fromCopy, request);
}
else
if(request->llarp)
{
// llarp::Addr anIp;
// llarp::LogInfo("Checking server request ", request);
@ -319,23 +183,34 @@ handle_recvfrom(const char *buffer, ssize_t nbytes, const struct sockaddr *from,
llarp_resolve_host(&dnsd->client, m_qName.c_str(), &handle_dnsc_result,
(void *)request);
}
else
{
hostRes = raw_resolve_host(m_qName.c_str());
llarp::Addr anIp(*hostRes);
llarp::LogInfo("DNS got ", anIp);
// writesend_dnss_response(struct sockaddr *hostRes, const struct sockaddr
// *from, dnsd_question_request *request)
sockaddr *fromCopy = new sockaddr(*from);
writesend_dnss_response(hostRes, fromCopy, request);
}
}
// this is called in net threadpool
void
llarp_handle_recvfrom(struct llarp_udp_io *udp, const struct sockaddr *paddr,
llarp_handle_dnsd_recvfrom(struct llarp_udp_io *udp, const struct sockaddr *paddr,
const void *buf, ssize_t sz)
{
lock_t lock(m_dnsd3_Mutex);
//lock_t lock(m_dnsd3_Mutex);
// llarp_link *link = static_cast< llarp_link * >(udp->user);
llarp::LogInfo("llarp Received Bytes ", sz);
dns_request *llarp_dns_request = new dns_request;
dnsd_question_request *llarp_dns_request = new dnsd_question_request;
// llarp::LogInfo("Creating server request ", &llarp_dns_request);
// llarp::LogInfo("Server UDP address ", udp);
// make a copy of the sockaddr
llarp_dns_request->from = new sockaddr(*paddr);
llarp_dns_request->user = (void *)udp;
llarp_dns_request->from = new sockaddr(*paddr);
llarp_dns_request->user = (void *)udp;
llarp_dns_request->llarp = true;
// set sock hook
llarp_dns_request->hook = &llarp_sendto_dns_hook_func;
@ -348,9 +223,10 @@ raw_handle_recvfrom(int *sockfd, const struct sockaddr *saddr, const void *buf,
ssize_t sz)
{
llarp::LogInfo("raw Received Bytes ", sz);
dns_request *llarp_dns_request = new dns_request;
dnsd_question_request *llarp_dns_request = new dnsd_question_request;
llarp_dns_request->from = (struct sockaddr *)saddr;
llarp_dns_request->user = (void *)sockfd;
llarp_dns_request->llarp = false;
llarp_dns_request->hook = &raw_sendto_dns_hook_func;
handle_recvfrom((char *)buf, sz, saddr, llarp_dns_request);
}

@ -1,29 +1,56 @@
#ifndef LIBLLARP_DNSD_HPP
#define LIBLLARP_DNSD_HPP
#include "dns.hpp" // question and dnsc
#include "dnsc.hpp"
#include <llarp/ev.h> // for sockaadr
typedef ssize_t (*sendto_dns_hook_func)(void *sock, const struct sockaddr *from,
const void *buffer, size_t length);
struct dns_request
struct dnsd_question_request
{
/// sock type
void *user;
// raw or llarp subsystem
bool llarp;
/// request id
int id;
std::string m_qName;
uint m_qType;
uint m_qClass;
/// question being asked
dns_msg_question question;
// request source socket
struct sockaddr *from;
sendto_dns_hook_func hook; // sendto hook tbh
// maybe a reference to dnsd_context incase of multiple
};
dns_msg_header *
decode_hdr(const char *buffer);
dns_msg_question *
decode_question(const char *buffer);
dns_msg_answer *
decode_answer(const char *buffer);
typedef bool (*intercept_query_hook)(struct dnsc_context *);
struct dnsd_context
{
/// DNS daemon socket to listen on
struct llarp_udp_io udp;
dnsc_context client;
/// custom data for intercept query hook
void *user;
/// hook function for intercepting dns requests
intercept_query_hook intercept;
};
void
llarp_handle_dnsd_recvfrom(struct llarp_udp_io *udp,
const struct sockaddr *paddr, const void *buf,
ssize_t sz);
/// initialize dns subsystem and bind socket
/// returns true on bind success otherwise returns false
bool
llarp_dnsd_init(struct dnsd_context *dnsd, struct llarp_ev_loop *netloop,
const char *dnsd_ifname, uint16_t dnsd_port,
const char *dnsc_hostname, uint16_t dnsc_port);
bool
llarp_dnsd_stop(struct dnsd_context *dnsd);
#endif

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