Mirror/zeek
1
0
Fork 0
mirror of https://github.com/zeek/zeek.git synced 2025-10-06 08:38:20 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 2

Store all mappings in a single map instead of split by type

Browse source 
This opens up the possibility of storing other request types outside
of T_A, T_PTR and T_TXT without requiring redoing the caching. It
also fixes the caching code in DNS_Mapping, adding a version number
to the start of the cache file so the cache structure can be modified
and old caches invalidated more easily.
This commit is contained in:
Tim Wojtulewicz 2022-02-07 12:41:03 -07:00
parent fb59239f41
commit e8f833b8a6
5 changed files with 261 additions and 154 deletions
Download patch file Download diff file Expand all files Collapse all files

45
src/DNS_Mapping.cc
View file

@ -1,16 +1,20 @@
#include "zeek/DNS_Mapping.h"
#include <ares_nameser.h>
#include "zeek/3rdparty/doctest.h"
#include "zeek/DNS_Mgr.h"
#include "zeek/Reporter.h"
namespace zeek::detail
{
DNS_Mapping::DNS_Mapping(std::string host, struct hostent* h, uint32_t ttl)
DNS_Mapping::DNS_Mapping(std::string host, struct hostent* h, uint32_t ttl, int type)
{
Init(h);
req_host = host;
req_ttl = ttl;
req_type = type;
if ( names.empty() )
names.push_back(std::move(host));
@ -21,6 +25,7 @@ DNS_Mapping::DNS_Mapping(const IPAddr& addr, struct hostent* h, uint32_t ttl)
Init(h);
req_addr = addr;
req_ttl = ttl;
req_type = T_PTR;
}
DNS_Mapping::DNS_Mapping(FILE* f)
@ -45,7 +50,7 @@ DNS_Mapping::DNS_Mapping(FILE* f)
int num_addrs;
if ( sscanf(buf, "%lf %d %512s %d %512s %d %d %" PRIu32, &creation_time, &is_req_host, req_buf,
&failed_local, name_buf, &map_type, &num_addrs, &req_ttl) != 8 )
&failed_local, name_buf, &req_type, &num_addrs, &req_ttl) != 8 )
{
no_mapping = true;
return;
@ -126,7 +131,6 @@ void DNS_Mapping::Init(struct hostent* h)
return;
}
map_type = h->h_addrtype;
if ( h->h_name )
// for now, just use the official name
// TODO: this could easily be expanded to include all of the aliases as well
@ -153,7 +157,7 @@ void DNS_Mapping::Clear()
addrs.clear();
addrs_val = nullptr;
no_mapping = false;
map_type = 0;
req_type = 0;
failed = true;
}
@ -161,7 +165,7 @@ void DNS_Mapping::Save(FILE* f) const
{
fprintf(f, "%.0f %d %s %d %s %d %zu %" PRIu32 "\n", creation_time, ! req_host.empty(),
req_host.empty() ? req_addr.AsString().c_str() : req_host.c_str(), failed,
names.empty() ? "*" : names[0].c_str(), map_type, addrs.size(), req_ttl);
names.empty() ? "*" : names[0].c_str(), req_type, addrs.size(), req_ttl);
for ( const auto& addr : addrs )
fprintf(f, "%s\n", addr.AsString().c_str());
@ -173,13 +177,38 @@ void DNS_Mapping::Merge(DNS_Mapping* other)
std::copy(other->addrs.begin(), other->addrs.end(), std::back_inserter(addrs));
}
// This value needs to be incremented if something changes in the data stored by Save(). This
// allows us to change the structure of the cache without breaking something in DNS_Mgr.
constexpr int FILE_VERSION = 1;
void DNS_Mapping::InitializeCache(FILE* f)
{
fprintf(f, "%d\n", FILE_VERSION);
}
bool DNS_Mapping::ValidateCacheVersion(FILE* f)
{
char buf[512];
if ( ! fgets(buf, sizeof(buf), f) )
return false;
int version;
if ( sscanf(buf, "%d", &version) != 1 )
{
reporter->Warning("Existing DNS cache did not have correct version, ignoring");
return false;
}
return FILE_VERSION == version;
}
//////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////
TEST_CASE("dns_mapping init null hostent")
{
DNS_Mapping mapping(std::string("www.apple.com"), nullptr, 123);
DNS_Mapping mapping("www.apple.com", nullptr, 123, T_A);
CHECK(! mapping.Valid());
CHECK(mapping.Addrs() == nullptr);
@ -202,7 +231,7 @@ TEST_CASE("dns_mapping init host")
std::vector<in_addr*> addrs = {&in4, NULL};
he.h_addr_list = reinterpret_cast<char**>(addrs.data());
DNS_Mapping mapping(std::string("testing.home"), &he, 123);
DNS_Mapping mapping("testing.home", &he, 123, T_A);
CHECK(mapping.Valid());
CHECK(mapping.ReqAddr() == IPAddr::v6_unspecified);
CHECK(strcmp(mapping.ReqHost(), "testing.home") == 0);
@ -347,7 +376,7 @@ TEST_CASE("dns_mapping multiple addresses")
std::vector<in_addr*> addrs = {&in4_1, &in4_2, NULL};
he.h_addr_list = reinterpret_cast<char**>(addrs.data());
DNS_Mapping mapping(std::string("testing.home"), &he, 123);
DNS_Mapping mapping("testing.home", &he, 123, T_A);
CHECK(mapping.Valid());
auto lva = mapping.Addrs();