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c-ares/test/dns-proto.cc

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#include "dns-proto.h"
// Include ares internal file for DNS protocol details
#include "ares.h"
#include "ares_dns.h"
#include <stdio.h>
#include <stdlib.h>
#include <sstream>
namespace ares {
std::string HexDump(std::vector<byte> data) {
std::stringstream ss;
for (size_t ii = 0; ii < data.size(); ii++) {
char buffer[2 + 1];
sprintf(buffer, "%02x", data[ii]);
ss << buffer;
}
return ss.str();
}
std::string HexDump(const byte *data, int len) {
return HexDump(std::vector<byte>(data, data + len));
}
std::string HexDump(const char *data, int len) {
return HexDump(reinterpret_cast<const byte*>(data), len);
}
std::string StatusToString(int status) {
switch (status) {
case ARES_SUCCESS: return "ARES_SUCCESS";
case ARES_ENODATA: return "ARES_ENODATA";
case ARES_EFORMERR: return "ARES_EFORMERR";
case ARES_ESERVFAIL: return "ARES_ESERVFAIL";
case ARES_ENOTFOUND: return "ARES_ENOTFOUND";
case ARES_ENOTIMP: return "ARES_ENOTIMP";
case ARES_EREFUSED: return "ARES_EREFUSED";
case ARES_EBADQUERY: return "ARES_EBADQUERY";
case ARES_EBADNAME: return "ARES_EBADNAME";
case ARES_EBADFAMILY: return "ARES_EBADFAMILY";
case ARES_EBADRESP: return "ARES_EBADRESP";
case ARES_ECONNREFUSED: return "ARES_ECONNREFUSED";
case ARES_ETIMEOUT: return "ARES_ETIMEOUT";
case ARES_EOF: return "ARES_EOF";
case ARES_EFILE: return "ARES_EFILE";
case ARES_ENOMEM: return "ARES_ENOMEM";
case ARES_EDESTRUCTION: return "ARES_EDESTRUCTION";
case ARES_EBADSTR: return "ARES_EBADSTR";
case ARES_EBADFLAGS: return "ARES_EBADFLAGS";
case ARES_ENONAME: return "ARES_ENONAME";
case ARES_EBADHINTS: return "ARES_EBADHINTS";
case ARES_ENOTINITIALIZED: return "ARES_ENOTINITIALIZED";
case ARES_ELOADIPHLPAPI: return "ARES_ELOADIPHLPAPI";
case ARES_EADDRGETNETWORKPARAMS: return "ARES_EADDRGETNETWORKPARAMS";
case ARES_ECANCELLED: return "ARES_ECANCELLED";
default: return "UNKNOWN";
}
}
std::string RcodeToString(int rcode) {
switch (rcode) {
case ns_r_noerror: return "NOERROR";
case ns_r_formerr: return "FORMERR";
case ns_r_servfail: return "SERVFAIL";
case ns_r_nxdomain: return "NXDOMAIN";
case ns_r_notimpl: return "NOTIMPL";
case ns_r_refused: return "REFUSED";
case ns_r_yxdomain: return "YXDOMAIN";
case ns_r_yxrrset: return "YXRRSET";
case ns_r_nxrrset: return "NXRRSET";
case ns_r_notauth: return "NOTAUTH";
case ns_r_notzone: return "NOTZONE";
case ns_r_badsig: return "BADSIG";
case ns_r_badkey: return "BADKEY";
case ns_r_badtime: return "BADTIME";
default: return "UNKNOWN";
}
}
std::string RRTypeToString(int rrtype) {
switch (rrtype) {
case ns_t_a: return "A";
case ns_t_ns: return "NS";
case ns_t_md: return "MD";
case ns_t_mf: return "MF";
case ns_t_cname: return "CNAME";
case ns_t_soa: return "SOA";
case ns_t_mb: return "MB";
case ns_t_mg: return "MG";
case ns_t_mr: return "MR";
case ns_t_null: return "NULL";
case ns_t_wks: return "WKS";
case ns_t_ptr: return "PTR";
case ns_t_hinfo: return "HINFO";
case ns_t_minfo: return "MINFO";
case ns_t_mx: return "MX";
case ns_t_txt: return "TXT";
case ns_t_rp: return "RP";
case ns_t_afsdb: return "AFSDB";
case ns_t_x25: return "X25";
case ns_t_isdn: return "ISDN";
case ns_t_rt: return "RT";
case ns_t_nsap: return "NSAP";
case ns_t_nsap_ptr: return "NSAP_PTR";
case ns_t_sig: return "SIG";
case ns_t_key: return "KEY";
case ns_t_px: return "PX";
case ns_t_gpos: return "GPOS";
case ns_t_aaaa: return "AAAA";
case ns_t_loc: return "LOC";
case ns_t_nxt: return "NXT";
case ns_t_eid: return "EID";
case ns_t_nimloc: return "NIMLOC";
case ns_t_srv: return "SRV";
case ns_t_atma: return "ATMA";
case ns_t_naptr: return "NAPTR";
case ns_t_kx: return "KX";
case ns_t_cert: return "CERT";
case ns_t_a6: return "A6";
case ns_t_dname: return "DNAME";
case ns_t_sink: return "SINK";
case ns_t_opt: return "OPT";
case ns_t_apl: return "APL";
case ns_t_ds: return "DS";
case ns_t_sshfp: return "SSHFP";
case ns_t_rrsig: return "RRSIG";
case ns_t_nsec: return "NSEC";
case ns_t_dnskey: return "DNSKEY";
case ns_t_tkey: return "TKEY";
case ns_t_tsig: return "TSIG";
case ns_t_ixfr: return "IXFR";
case ns_t_axfr: return "AXFR";
case ns_t_mailb: return "MAILB";
case ns_t_maila: return "MAILA";
case ns_t_any: return "ANY";
case ns_t_zxfr: return "ZXFR";
case ns_t_max: return "MAX";
default: return "UNKNOWN";
}
}
std::string ClassToString(int qclass) {
switch (qclass) {
case ns_c_in: return "IN";
case ns_c_chaos: return "CHAOS";
case ns_c_hs: return "HESIOD";
case ns_c_none: return "NONE";
case ns_c_any: return "ANY";
default: return "UNKNOWN";
}
}
std::string AddressToString(const void* vaddr, int len) {
const byte* addr = reinterpret_cast<const byte*>(vaddr);
std::stringstream ss;
if (len == 4) {
char buffer[4*4 + 3 + 1];
sprintf(buffer, "%u.%u.%u.%u",
(unsigned char)addr[0],
(unsigned char)addr[1],
(unsigned char)addr[2],
(unsigned char)addr[3]);
ss << buffer;
} else if (len == 16) {
for (int ii = 0; ii < 16; ii+=2) {
if (ii > 0) ss << ':';
char buffer[4 + 1];
sprintf(buffer, "%02x%02x", (unsigned char)addr[ii], (unsigned char)addr[ii+1]);
ss << buffer;
}
} else {
ss << "!" << HexDump(addr, len) << "!";
}
return ss.str();
}
std::string PacketToString(const std::vector<byte>& packet) {
const byte* data = packet.data();
int len = packet.size();
std::stringstream ss;
if (len < NS_HFIXEDSZ) {
ss << "(too short, len " << len << ")";
return ss.str();
}
ss << ((DNS_HEADER_QR(data) == 0) ? "REQ " : "RSP ");
switch (DNS_HEADER_OPCODE(data)) {
case ns_o_query: ss << "QRY "; break;
case ns_o_iquery: ss << "IQRY "; break;
case ns_o_status: ss << "STATUS "; break;
case ns_o_notify: ss << "NOTIFY "; break;
case ns_o_update: ss << "UPDATE "; break;
default: ss << "UNKNOWN(" << DNS_HEADER_OPCODE(data) << ") "; break;
}
if (DNS_HEADER_AA(data)) ss << "AA ";
if (DNS_HEADER_TC(data)) ss << "TC ";
if (DNS_HEADER_RD(data)) ss << "RD ";
if (DNS_HEADER_RA(data)) ss << "RA ";
if (DNS_HEADER_Z(data)) ss << "Z ";
if (DNS_HEADER_QR(data) == 1) ss << RcodeToString(DNS_HEADER_RCODE(data));
int nquestions = DNS_HEADER_QDCOUNT(data);
int nanswers = DNS_HEADER_ANCOUNT(data);
int nauths = DNS_HEADER_NSCOUNT(data);
int nadds = DNS_HEADER_ARCOUNT(data);
const byte* pq = data + NS_HFIXEDSZ;
len -= NS_HFIXEDSZ;
for (int ii = 0; ii < nquestions; ii++) {
ss << " Q:" << QuestionToString(packet, &pq, &len);
}
const byte* prr = pq;
for (int ii = 0; ii < nanswers; ii++) {
ss << " A:" << RRToString(packet, &prr, &len);
}
for (int ii = 0; ii < nauths; ii++) {
ss << " AUTH:" << RRToString(packet, &prr, &len);
}
for (int ii = 0; ii < nadds; ii++) {
ss << " ADD:" << RRToString(packet, &prr, &len);
}
return ss.str();
}
std::string QuestionToString(const std::vector<byte>& packet,
const byte** data, int* len) {
std::stringstream ss;
ss << "{";
if (*len < NS_QFIXEDSZ) {
ss << "(too short, len " << *len << ")";
return ss.str();
}
char *name = nullptr;
long enclen;
int rc = ares_expand_name(*data, packet.data(), packet.size(), &name, &enclen);
if (rc != ARES_SUCCESS) {
ss << "(error from ares_expand_name)";
return ss.str();
}
if (enclen > *len) {
ss << "(error, encoded name len " << enclen << "bigger than remaining data " << *len << " bytes)";
return ss.str();
}
*len -= enclen;
*data += enclen;
ss << "'" << name << "' ";
free(name);
if (*len < NS_QFIXEDSZ) {
ss << "(too short, len left " << *len << ")";
return ss.str();
}
ss << ClassToString(DNS_QUESTION_CLASS(*data)) << " ";
ss << RRTypeToString(DNS_QUESTION_TYPE(*data));
*data += NS_QFIXEDSZ;
*len -= NS_QFIXEDSZ;
ss << "}";
return ss.str();
}
std::string RRToString(const std::vector<byte>& packet,
const byte** data, int* len) {
std::stringstream ss;
ss << "{";
if (*len < NS_RRFIXEDSZ) {
ss << "too short, len " << *len << ")";
return ss.str();
}
char *name = nullptr;
long enclen;
int rc = ares_expand_name(*data, packet.data(), packet.size(), &name, &enclen);
if (rc != ARES_SUCCESS) {
ss << "(error from ares_expand_name)";
return ss.str();
}
if (enclen > *len) {
ss << "(error, encoded name len " << enclen << "bigger than remaining data " << *len << " bytes)";
return ss.str();
}
*len -= enclen;
*data += enclen;
ss << "'" << name << "' ";
free(name);
name = nullptr;
if (*len < NS_RRFIXEDSZ) {
ss << "(too short, len left " << *len << ")";
return ss.str();
}
int rrtype = DNS_RR_TYPE(*data);
if (rrtype == ns_t_opt) {
ss << "MAXUDP=" << DNS_RR_CLASS(*data) << " ";
ss << RRTypeToString(rrtype) << " ";
ss << "RCODE2=" << DNS_RR_TTL(*data);
} else {
ss << ClassToString(DNS_RR_CLASS(*data)) << " ";
ss << RRTypeToString(rrtype) << " ";
ss << "TTL=" << DNS_RR_TTL(*data);
}
int rdatalen = DNS_RR_LEN(*data);
*data += NS_RRFIXEDSZ;
*len -= NS_RRFIXEDSZ;
if (*len < rdatalen) {
ss << "(RR too long at " << rdatalen << ", len left " << *len << ")";
} else {
switch (rrtype) {
case ns_t_a:
case ns_t_aaaa:
ss << " " << AddressToString(*data, rdatalen);
break;
case ns_t_txt: {
const byte* p = *data;
while (p < (*data + rdatalen)) {
int len = *p++;
if ((p + len) <= (*data + rdatalen)) {
std::string txt(p, p + len);
ss << " " << len << ":'" << txt << "'";
} else {
ss << "(string too long)";
}
p += len;
}
break;
}
case ns_t_cname:
case ns_t_ns:
case ns_t_ptr: {
int rc = ares_expand_name(*data, packet.data(), packet.size(), &name, &enclen);
if (rc != ARES_SUCCESS) {
ss << "(error from ares_expand_name)";
break;
}
ss << " '" << name << "'";
free(name);
break;
}
case ns_t_mx:
if (rdatalen > 2) {
int rc = ares_expand_name(*data + 2, packet.data(), packet.size(), &name, &enclen);
if (rc != ARES_SUCCESS) {
ss << "(error from ares_expand_name)";
break;
}
ss << " " << DNS__16BIT(*data) << " '" << name << "'";
free(name);
} else {
ss << "(RR too short)";
}
break;
case ns_t_srv: {
if (rdatalen > 6) {
const byte* p = *data;
unsigned long prio = DNS__16BIT(p);
unsigned long weight = DNS__16BIT(p + 2);
unsigned long port = DNS__16BIT(p + 4);
p += 6;
int rc = ares_expand_name(p, packet.data(), packet.size(), &name, &enclen);
if (rc != ARES_SUCCESS) {
ss << "(error from ares_expand_name)";
break;
}
ss << prio << " " << weight << " " << port << " '" << name << "'";
free(name);
} else {
ss << "(RR too short)";
}
break;
}
case ns_t_soa: {
const byte* p = *data;
int rc = ares_expand_name(p, packet.data(), packet.size(), &name, &enclen);
if (rc != ARES_SUCCESS) {
ss << "(error from ares_expand_name)";
break;
}
ss << " '" << name << "'";
free(name);
p += enclen;
rc = ares_expand_name(p, packet.data(), packet.size(), &name, &enclen);
if (rc != ARES_SUCCESS) {
ss << "(error from ares_expand_name)";
break;
}
ss << " '" << name << "'";
free(name);
p += enclen;
if ((p + 20) <= (*data + rdatalen)) {
unsigned long serial = DNS__32BIT(p);
unsigned long refresh = DNS__32BIT(p + 4);
unsigned long retry = DNS__32BIT(p + 8);
unsigned long expire = DNS__32BIT(p + 12);
unsigned long minimum = DNS__32BIT(p + 16);
ss << " " << serial << " " << refresh << " " << retry << " " << expire << " " << minimum;
} else {
ss << "(RR too short)";
}
break;
}
case ns_t_naptr: {
if (rdatalen > 7) {
const byte* p = *data;
unsigned long order = DNS__16BIT(p);
unsigned long pref = DNS__16BIT(p + 2);
p += 4;
ss << order << " " << pref;
int len = *p++;
std::string flags(p, p + len);
ss << " " << flags;
p += len;
len = *p++;
std::string service(p, p + len);
ss << " '" << service << "'";
p += len;
len = *p++;
std::string regexp(p, p + len);
ss << " '" << regexp << "'";
p += len;
int rc = ares_expand_name(p, packet.data(), packet.size(), &name, &enclen);
if (rc != ARES_SUCCESS) {
ss << "(error from ares_expand_name)";
break;
}
ss << " '" << name << "'";
free(name);
} else {
ss << "(RR too short)";
}
break;
}
default:
ss << " " << HexDump(*data, rdatalen);
break;
}
}
*data += rdatalen;
*len -= rdatalen;
ss << "}";
return ss.str();
}
void PushInt32(std::vector<byte>* data, int value) {
data->push_back((value & 0xff000000) >> 24);
data->push_back((value & 0x00ff0000) >> 16);
data->push_back((value & 0x0000ff00) >> 8);
data->push_back(value & 0x000000ff);
}
void PushInt16(std::vector<byte>* data, int value) {
data->push_back((value & 0xff00) >> 8);
data->push_back(value & 0x00ff);
}
std::vector<byte> EncodeString(const std::string& name) {
std::vector<byte> data;
std::stringstream ss(name);
std::string label;
// TODO: cope with escapes
while (std::getline(ss, label, '.')) {
data.push_back(label.length());
data.insert(data.end(), label.begin(), label.end());
}
data.push_back(0);
return data;
}
std::vector<byte> DNSQuestion::data() const {
std::vector<byte> data;
std::vector<byte> encname = EncodeString(name_);
data.insert(data.end(), encname.begin(), encname.end());
PushInt16(&data, rrtype_);
PushInt16(&data, qclass_);
return data;
}
std::vector<byte> DNSRR::data() const {
std::vector<byte> data = DNSQuestion::data();
PushInt32(&data, ttl_);
return data;
}
std::vector<byte> DNSSingleNameRR::data() const {
std::vector<byte> data = DNSRR::data();
std::vector<byte> encname = EncodeString(other_);
int len = encname.size();
PushInt16(&data, len);
data.insert(data.end(), encname.begin(), encname.end());
return data;
}
std::vector<byte> DNSTxtRR::data() const {
std::vector<byte> data = DNSRR::data();
int len = 0;
for (const std::string& txt : txt_) {
len += (1 + txt.size());
}
PushInt16(&data, len);
for (const std::string& txt : txt_) {
data.push_back(txt.size());
data.insert(data.end(), txt.begin(), txt.end());
}
return data;
}
std::vector<byte> DNSMxRR::data() const {
std::vector<byte> data = DNSRR::data();
std::vector<byte> encname = EncodeString(other_);
int len = 2 + encname.size();
PushInt16(&data, len);
PushInt16(&data, pref_);
data.insert(data.end(), encname.begin(), encname.end());
return data;
}
std::vector<byte> DNSSrvRR::data() const {
std::vector<byte> data = DNSRR::data();
std::vector<byte> encname = EncodeString(target_);
int len = 6 + encname.size();
PushInt16(&data, len);
PushInt16(&data, prio_);
PushInt16(&data, weight_);
PushInt16(&data, port_);
data.insert(data.end(), encname.begin(), encname.end());
return data;
}
std::vector<byte> DNSAddressRR::data() const {
std::vector<byte> data = DNSRR::data();
int len = addr_.size();
PushInt16(&data, len);
data.insert(data.end(), addr_.begin(), addr_.end());
return data;
}
std::vector<byte> DNSSoaRR::data() const {
std::vector<byte> data = DNSRR::data();
std::vector<byte> encname1 = EncodeString(nsname_);
std::vector<byte> encname2 = EncodeString(rname_);
int len = encname1.size() + encname2.size() + 5*4;
PushInt16(&data, len);
data.insert(data.end(), encname1.begin(), encname1.end());
data.insert(data.end(), encname2.begin(), encname2.end());
PushInt32(&data, serial_);
PushInt32(&data, refresh_);
PushInt32(&data, retry_);
PushInt32(&data, expire_);
PushInt32(&data, minimum_);
return data;
}
std::vector<byte> DNSOptRR::data() const {
std::vector<byte> data = DNSRR::data();
int len = 0;
for (const DNSOption& opt : opts_) {
len += (4 + opt.data_.size());
}
PushInt16(&data, len);
for (const DNSOption& opt : opts_) {
PushInt16(&data, opt.code_);
PushInt16(&data, opt.data_.size());
data.insert(data.end(), opt.data_.begin(), opt.data_.end());
}
return data;
}
std::vector<byte> DNSNaptrRR::data() const {
std::vector<byte> data = DNSRR::data();
std::vector<byte> encname = EncodeString(replacement_);
int len = (4 + 1 + flags_.size() + 1 + service_.size() + 1 + regexp_.size() + encname.size());
PushInt16(&data, len);
PushInt16(&data, order_);
PushInt16(&data, pref_);
data.push_back(flags_.size());
data.insert(data.end(), flags_.begin(), flags_.end());
data.push_back(service_.size());
data.insert(data.end(), service_.begin(), service_.end());
data.push_back(regexp_.size());
data.insert(data.end(), regexp_.begin(), regexp_.end());
data.insert(data.end(), encname.begin(), encname.end());
return data;
}
std::vector<byte> DNSPacket::data() const {
std::vector<byte> data;
PushInt16(&data, qid_);
byte b = 0x00;
if (response_) b |= 0x80;
b |= ((opcode_ & 0x0f) << 3);
if (aa_) b |= 0x04;
if (tc_) b |= 0x02;
if (rd_) b |= 0x01;
data.push_back(b);
b = 0x00;
if (ra_) b |= 0x80;
if (z_) b |= 0x40;
if (ad_) b |= 0x20;
if (cd_) b |= 0x10;
b |= (rcode_ & 0x0f);
data.push_back(b);
int count = questions_.size();
PushInt16(&data, count);
count = answers_.size();
PushInt16(&data, count);
count = auths_.size();
PushInt16(&data, count);
count = adds_.size();
PushInt16(&data, count);
for (const std::unique_ptr<DNSQuestion>& question : questions_) {
std::vector<byte> qdata = question->data();
data.insert(data.end(), qdata.begin(), qdata.end());
}
for (const std::unique_ptr<DNSRR>& rr : answers_) {
std::vector<byte> rrdata = rr->data();
data.insert(data.end(), rrdata.begin(), rrdata.end());
}
for (const std::unique_ptr<DNSRR>& rr : auths_) {
std::vector<byte> rrdata = rr->data();
data.insert(data.end(), rrdata.begin(), rrdata.end());
}
for (const std::unique_ptr<DNSRR>& rr : adds_) {
std::vector<byte> rrdata = rr->data();
data.insert(data.end(), rrdata.begin(), rrdata.end());
}
return data;
}
} // namespace ares
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