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Code Issues Releases Wiki Activity

Fixed some bugs in DNS. Added some helper functions.

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This commit is contained in:
Matias Fontanini
2012-04-02 17:12:04 -03:00
parent 44dbdbb116
commit ae7e1b3d0d
2 changed files with 190 additions and 33 deletions
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84
include/dns.h
View File

@@ -144,6 +144,13 @@ namespace Tins {
*/
DNS(const uint8_t *buffer, uint32_t total_sz);
/**
* \brief Copy constructor.
*
* \param other The DNS object to be copied.
*/
DNS(const DNS &other);
/**
* \brief Destructor.
*/
@@ -368,6 +375,13 @@ namespace Tins {
*/
void add_query(const std::string &name, QueryType type, QueryClass qclass);
/**
* \brief Add a query to perform.
*
* \param query The query to be added.
*/
void add_query(const Query &query);
/**
* \brief Add a query response.
*
@@ -379,6 +393,31 @@ namespace Tins {
*/
void add_answer(const std::string &name, QueryType type, QueryClass qclass,
uint32_t ttl, uint32_t ip);
/**
* \brief Add a query response.
*
* \param name The resolved name.
* \param type The type of this answer.
* \param qclass The class of this answer.
* \param ttl The time-to-live of this answer.
* \param dname The domain of the resolved name.
*/
void add_answer(const std::string &name, QueryType type, QueryClass qclass,
uint32_t ttl, const std::string &dname);
/**
* \brief Add a query response.
*
* \param name The resolved name.
* \param type The type of this answer.
* \param qclass The class of this answer.
* \param ttl The time-to-live of this answer.
* \param data The data of this option.
* \param sz The size of the data.
*/
void add_answer(const std::string &name, QueryType type, QueryClass qclass,
uint32_t ttl, const uint8_t *data, uint32_t sz);
/**
* \brief Add an authority record.
@@ -387,10 +426,11 @@ namespace Tins {
* \param type The type of this record.
* \param qclass The class of this record.
* \param ttl The time-to-live of this record.
* \param ip The ip address of the resolved name.
* \param data The data of this option.
* \param sz The size of the data.
*/
void add_authority(const std::string &name, QueryType type, QueryClass qclass,
uint32_t ttl, uint32_t ip);
uint32_t ttl, const uint8_t *data, uint32_t sz);
/**
* \brief Add an additional record.
@@ -418,6 +458,13 @@ namespace Tins {
* record.
*/
std::list<Resource> dns_answers();
/**
* \brief Clones this PDU.
*
* \sa PDU::clone_pdu
*/
PDU *clone_pdu() const;
private:
struct dnshdr {
uint16_t id;
@@ -445,22 +492,17 @@ namespace Tins {
uint8_t *data;
uint16_t data_sz;
ResourceRecord(uint8_t *d = 0, uint16_t len = 0) : data_sz(len) {
if(d)
ResourceRecord(const uint8_t *d = 0, uint16_t len = 0) : data_sz(len) {
if(d && len) {
data = new uint8_t[len];
std::memcpy(data, d, data_sz);
}
}
virtual ~ResourceRecord() {}
uint32_t write(uint8_t *buffer) const {
uint32_t sz(do_write(buffer));
buffer += sz;
std::memcpy(buffer, &info, sizeof(info));
buffer += sizeof(info);
*((uint16_t*)buffer) = Utils::net_to_host_s(data_sz);
buffer += sizeof(uint16_t);
std::memcpy(buffer, data, data_sz);
return sz + sizeof(info) + sizeof(uint16_t) + data_sz;
}
virtual ResourceRecord *clone() const = 0;
void copy_fields(ResourceRecord *other) const;
uint32_t write(uint8_t *buffer) const;
virtual uint32_t do_write(uint8_t *buffer) const = 0;
virtual uint32_t size() const = 0;
virtual bool matches(const std::string &dname) { return false; }
@@ -476,19 +518,20 @@ namespace Tins {
struct OffsetedResourceRecord : public ResourceRecord {
uint16_t offset;
OffsetedResourceRecord(uint16_t off, uint8_t *data = 0, uint16_t len = 0) : ResourceRecord(data,len), offset(off | 0xc0) {}
OffsetedResourceRecord(uint16_t off, const uint8_t *data = 0, uint16_t len = 0) : ResourceRecord(data,len), offset(off | 0xc0) {}
uint32_t do_write(uint8_t *buffer) const {
std::memcpy(buffer, &offset, sizeof(offset));
return sizeof(offset);
}
uint32_t size() const { return sizeof(ResourceRecord::info) + sizeof(offset) + data_sz + sizeof(uint16_t); }
ResourceRecord *clone() const;
};
struct NamedResourceRecord : public ResourceRecord {
std::string name;
NamedResourceRecord(const std::string &nm, uint8_t *data = 0, uint16_t len = 0) : ResourceRecord(data,len), name(nm) {}
NamedResourceRecord(const std::string &nm, const uint8_t *data = 0, uint16_t len = 0) : ResourceRecord(data,len), name(nm) {}
uint32_t do_write(uint8_t *buffer) const {
std::memcpy(buffer, name.c_str(), name.size() + 1);
@@ -504,9 +547,11 @@ namespace Tins {
const std::string *dname_pointer() const {
return &name;
}
ResourceRecord *clone() const;
};
typedef std::map<uint16_t, std::string> SuffixMap;
typedef std::map<uint16_t, uint16_t> SuffixIndices;
const uint8_t *build_resource_list(std::list<ResourceRecord*> &lst, const uint8_t *ptr, uint32_t &sz, uint16_t nrecs);
uint32_t find_domain_name(const std::string &dname);
@@ -519,17 +564,24 @@ namespace Tins {
void compose_name(const uint8_t *ptr, uint32_t sz, std::string &out);
void convert_resources(const std::list<ResourceRecord*> &lst, std::list<Resource> &res);
ResourceRecord *make_record(const std::string &name, QueryType type, QueryClass qclass, uint32_t ttl, uint32_t ip);
ResourceRecord *make_record(const std::string &name, QueryType type, QueryClass qclass, uint32_t ttl, const std::string &dname);
ResourceRecord *make_record(const std::string &name, QueryType type, QueryClass qclass, uint32_t ttl, const uint8_t *ptr, uint32_t len);
void add_suffix(uint32_t index, const uint8_t *data, uint32_t sz);
uint32_t build_suffix_map(uint32_t index, const std::list<ResourceRecord*> &lst);
uint32_t build_suffix_map(uint32_t index, const std::list<Query> &lst);
void build_suffix_map();
void copy_list(const std::list<ResourceRecord*> &from, std::list<ResourceRecord*> &to) const;
void copy_fields(const DNS *other);
dnshdr dns;
uint32_t extra_size;
std::list<Query> queries;
std::list<ResourceRecord*> ans, arity, addit;
SuffixMap suffixes;
SuffixIndices suffix_indices;
};
};
#endif // __DNS_H

139
src/dns.cpp
View File

@@ -62,6 +62,11 @@ Tins::DNS::DNS(const uint8_t *buffer, uint32_t total_sz) : PDU(255), extra_size(
build_resource_list(addit, buffer, total_sz, additional());
}
Tins::DNS::DNS(const DNS &other) : PDU(255) {
copy_fields(&other);
copy_inner_pdu(other);
}
const uint8_t *Tins::DNS::build_resource_list(list<ResourceRecord*> &lst, const uint8_t *ptr, uint32_t &sz, uint16_t nrecs) {
const uint8_t *ptr_end(ptr + sz);
const uint8_t *parse_start(ptr);
@@ -188,14 +193,39 @@ void Tins::DNS::add_query(const string &name, QueryType type, QueryClass qclass)
dns.questions = Utils::net_to_host_s(queries.size());
}
void Tins::DNS::add_query(const Query &query) {
add_query(
query.name,
static_cast<QueryType>(query.type),
static_cast<QueryClass>(query.qclass)
);
}
void Tins::DNS::add_answer(const string &name, QueryType type, QueryClass qclass, uint32_t ttl, uint32_t ip) {
ResourceRecord *res = make_record(name, type, qclass, ttl, ip);
ans.push_back(res);
dns.answers = Utils::net_to_host_s(ans.size());
}
void Tins::DNS::add_authority(const string &name, QueryType type, QueryClass qclass, uint32_t ttl, uint32_t ip) {
ResourceRecord *res = make_record(name, type, qclass, ttl, ip);
void Tins::DNS::add_answer(const std::string &name, QueryType type, QueryClass qclass,
uint32_t ttl, const std::string &dname) {
string new_str;
parse_domain_name(dname, new_str);
ResourceRecord *res = make_record(name, type, qclass, ttl, new_str);
ans.push_back(res);
dns.answers = Utils::net_to_host_s(ans.size());
}
void Tins::DNS::add_answer(const std::string &name, QueryType type, QueryClass qclass,
uint32_t ttl, const uint8_t *data, uint32_t sz) {
ResourceRecord *res = make_record(name, type, qclass, ttl, data, sz);
ans.push_back(res);
dns.answers = Utils::net_to_host_s(ans.size());
}
void Tins::DNS::add_authority(const string &name, QueryType type,
QueryClass qclass, uint32_t ttl, const uint8_t *data, uint32_t sz) {
ResourceRecord *res = make_record(name, type, qclass, ttl, data, sz);
arity.push_back(res);
dns.authority = Utils::net_to_host_s(arity.size());
}
@@ -207,15 +237,23 @@ void Tins::DNS::add_additional(const string &name, QueryType type, QueryClass qc
}
Tins::DNS::ResourceRecord *Tins::DNS::make_record(const std::string &name, QueryType type, QueryClass qclass, uint32_t ttl, uint32_t ip) {
ip = Utils::net_to_host_l(ip);
return make_record(name, type, qclass, ttl, reinterpret_cast<uint8_t*>(&ip), sizeof(ip));
}
Tins::DNS::ResourceRecord *Tins::DNS::make_record(const std::string &name, QueryType type, QueryClass qclass, uint32_t ttl, const std::string &dname) {
return make_record(name, type, qclass, ttl, reinterpret_cast<const uint8_t*>(dname.c_str()), dname.size() + 1);
}
Tins::DNS::ResourceRecord *Tins::DNS::make_record(const std::string &name, QueryType type, QueryClass qclass, uint32_t ttl, const uint8_t *ptr, uint32_t len) {
string nm;
parse_domain_name(name, nm);
uint16_t index = find_domain_name(nm);
ResourceRecord *res;
ip = Utils::net_to_host_l(ip);
if(index)
res = new OffsetedResourceRecord(Utils::net_to_host_s(index), (uint8_t*)&ip, sizeof(uint32_t));
res = new OffsetedResourceRecord(Utils::net_to_host_s(index), ptr, len);
else
res = new NamedResourceRecord(nm, (uint8_t*)&ip, sizeof(uint32_t));
res = new NamedResourceRecord(nm, ptr, len);
res->info.type = Utils::net_to_host_s(type);
res->info.qclass = Utils::net_to_host_s(qclass);
res->info.ttl = Utils::net_to_host_l(ttl);
@@ -303,10 +341,18 @@ uint8_t *Tins::DNS::serialize_list(const std::list<ResourceRecord*> &lst, uint8_
void Tins::DNS::add_suffix(uint32_t index, const uint8_t *data, uint32_t sz) {
uint32_t i(0), suff_sz(data[0]);
while(i + suff_sz + 1 <= sz && suff_sz) {
i++;
suffixes.insert(std::make_pair(index + i - 1, string(data + i, data + i + suff_sz)));
i += suff_sz;
SuffixMap::iterator it;
while((i + suff_sz + 1 <= sz || (suff_sz == 0xc0 && i + 1 < sz)) && suff_sz) {
if((suff_sz & 0xc0)) {
if((it = suffixes.find(data[i+1])) != suffixes.end())
suffix_indices[index + i] = data[i+1];
i += sizeof(uint16_t);
}
else {
++i;
suffixes.insert(std::make_pair(index + i - 1, string(data + i, data + i + suff_sz)));
i += suff_sz;
}
if(i < sz)
suff_sz = data[i];
}
@@ -331,7 +377,6 @@ uint32_t Tins::DNS::build_suffix_map(uint32_t index, const list<ResourceRecord*>
return index;
}
uint32_t Tins::DNS::build_suffix_map(uint32_t index, const list<Query> &lst) {
for(list<Query>::const_iterator it(lst.begin()); it != lst.end(); ++it) {
add_suffix(index, (uint8_t*)it->name.c_str(), it->name.size());
@@ -357,16 +402,24 @@ void Tins::DNS::compose_name(const uint8_t *ptr, uint32_t sz, std::string &out)
uint16_t index = Utils::net_to_host_s(*((uint16_t*)(ptr + i)));
index &= 0x3fff;
SuffixMap::iterator it(suffixes.find(index));
assert(it != suffixes.end());
SuffixIndices::iterator suff_it(suffix_indices.find(index));
assert(it != suffixes.end() && suff_it == suffix_indices.end());
bool first(true);
do {
if(!first)
out.push_back('.');
first = false;
out += it->second;
index += it->second.size() + 1;
if(it != suffixes.end()) {
if(!first)
out.push_back('.');
first = false;
out += it->second;
index += it->second.size() + 1;
}
else
index = suff_it->second;
it = suffixes.find(index);
} while(it != suffixes.end());
if(it == suffixes.end())
suff_it = suffix_indices.find(index);
} while(it != suffixes.end() || suff_it != suffix_indices.end());
break;
}
else {
@@ -422,4 +475,56 @@ list<Tins::DNS::Resource> Tins::DNS::dns_answers() {
return res;
}
Tins::PDU *Tins::DNS::clone_pdu() const {
DNS *new_pdu = new DNS();
new_pdu->copy_fields(this);
new_pdu->copy_inner_pdu(*this);
return new_pdu;
}
void Tins::DNS::copy_fields(const DNS *other) {
std::memcpy(&dns, &other->dns, sizeof(dns));
extra_size = other->extra_size;
queries = other->queries;
copy_list(other->ans, ans);
copy_list(other->arity, arity);
copy_list(other->addit, addit);
}
void Tins::DNS::copy_list(const list<ResourceRecord*> &from, list<ResourceRecord*> &to) const {
for(list<ResourceRecord*>::const_iterator it(from.begin()); it != from.end(); ++it) {
to.push_back((*it)->clone());
}
}
// ResourceRecord
void Tins::DNS::ResourceRecord::copy_fields(ResourceRecord *other) const {
std::memcpy(&other->info, &info, sizeof(info));
other->data_sz = data_sz;
other->data = new uint8_t[data_sz];
std::memcpy(other->data, data, data_sz);
}
uint32_t Tins::DNS::ResourceRecord::write(uint8_t *buffer) const {
uint32_t sz(do_write(buffer));
buffer += sz;
std::memcpy(buffer, &info, sizeof(info));
buffer += sizeof(info);
*((uint16_t*)buffer) = Utils::net_to_host_s(data_sz);
buffer += sizeof(uint16_t);
std::memcpy(buffer, data, data_sz);
return sz + sizeof(info) + sizeof(uint16_t) + data_sz;
}
Tins::DNS::ResourceRecord *Tins::DNS::OffsetedResourceRecord::clone() const {
ResourceRecord *r = new OffsetedResourceRecord(offset);
copy_fields(r);
return r;
}
Tins::DNS::ResourceRecord *Tins::DNS::NamedResourceRecord::clone() const {
ResourceRecord *r = new NamedResourceRecord(name);
copy_fields(r);
return r;
}