mirror of
https://github.com/matrix-construct/construct
synced 2024-11-25 16:22:35 +01:00
281 lines
6.7 KiB
C++
281 lines
6.7 KiB
C++
// Matrix Construct
|
|
//
|
|
// Copyright (C) Matrix Construct Developers, Authors & Contributors
|
|
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
|
|
//
|
|
// Permission to use, copy, modify, and/or distribute this software for any
|
|
// purpose with or without fee is hereby granted, provided that the above
|
|
// copyright notice and this permission notice is present in all copies. The
|
|
// full license for this software is available in the LICENSE file.
|
|
|
|
#include "s_dns.h"
|
|
|
|
decltype(ircd::net::dns::cache::clear_nxdomain)
|
|
ircd::net::dns::cache::clear_nxdomain
|
|
{
|
|
{ "name", "ircd.net.dns.cache.clear_nxdomain" },
|
|
{ "default", 43200L },
|
|
};
|
|
|
|
decltype(ircd::net::dns::cache::min_ttl)
|
|
ircd::net::dns::cache::min_ttl
|
|
{
|
|
{ "name", "ircd.net.dns.cache.min_ttl" },
|
|
{ "default", 900L },
|
|
};
|
|
|
|
decltype(ircd::net::dns::cache::cache_A)
|
|
ircd::net::dns::cache::cache_A;
|
|
|
|
decltype(ircd::net::dns::cache::cache_SRV)
|
|
ircd::net::dns::cache::cache_SRV;
|
|
|
|
bool
|
|
ircd::net::dns::cache::_for_each(const uint16_t &type,
|
|
const closure &closure)
|
|
{
|
|
switch(type)
|
|
{
|
|
case 1: // A
|
|
return _for_each_(cache_A, closure);
|
|
|
|
case 33: // SRV
|
|
return _for_each_(cache_SRV, closure);
|
|
|
|
default:
|
|
return true;
|
|
}
|
|
}
|
|
|
|
/// This function has an opportunity to respond from the DNS cache. If it
|
|
/// returns true, that indicates it responded by calling back the user and
|
|
/// nothing further should be done for them. If it returns false, that
|
|
/// indicates it did not respond and to proceed normally. The response can
|
|
/// be of a cached successful result, or a cached error. Both will return
|
|
/// true.
|
|
bool
|
|
ircd::net::dns::cache::_get(const hostport &hp,
|
|
const opts &opts,
|
|
const callback &cb)
|
|
{
|
|
// It's no use putting the result record array on the stack in case this
|
|
// function is either called from an ircd::ctx or calls back an ircd::ctx.
|
|
// If the ctx yields the records can still be evicted from the cache.
|
|
// It's better to just force the user to conform here rather than adding
|
|
// ref counting and other pornographic complications to this cache.
|
|
const ctx::critical_assertion ca;
|
|
thread_local std::array<const rfc1035::record *, MAX_COUNT> record;
|
|
std::exception_ptr eptr;
|
|
size_t count{0};
|
|
|
|
if(opts.qtype == 33) // deduced SRV query
|
|
{
|
|
assert(!empty(host(hp)));
|
|
thread_local char srvbuf[512];
|
|
const string_view srvhost
|
|
{
|
|
make_SRV_key(srvbuf, hp, opts)
|
|
};
|
|
|
|
auto &map{cache_SRV};
|
|
const auto pit{map.equal_range(srvhost)};
|
|
if(pit.first == pit.second)
|
|
return false;
|
|
|
|
const auto &now{ircd::time()};
|
|
for(auto it(pit.first); it != pit.second; )
|
|
{
|
|
const auto &rr{it->second};
|
|
|
|
// Cached entry is too old, ignore and erase
|
|
if(rr.ttl < now)
|
|
{
|
|
it = map.erase(it);
|
|
continue;
|
|
}
|
|
|
|
// Cached entry is a cached error, we set the eptr, but also
|
|
// include the record and increment the count like normal.
|
|
if((!rr.tgt || !rr.port) && opts.nxdomain_exceptions && !eptr)
|
|
{
|
|
//TODO: we don't cache what the error was, assuming it's
|
|
//TODO: NXDomain can be incorrect and in bad ways downstream...
|
|
static const auto rcode{3}; //NXDomain
|
|
eptr = std::make_exception_ptr(rfc1035::error
|
|
{
|
|
"protocol error #%u (cached) :%s", rcode, rfc1035::rcode.at(rcode)
|
|
});
|
|
}
|
|
|
|
if(count < record.size())
|
|
record.at(count++) = &rr;
|
|
|
|
++it;
|
|
}
|
|
}
|
|
else if(opts.qtype == 1)
|
|
{
|
|
auto &map{cache_A};
|
|
const auto &key{rstrip(host(hp), '.')};
|
|
if(unlikely(empty(key)))
|
|
return false;
|
|
|
|
const auto pit{map.equal_range(key)};
|
|
if(pit.first == pit.second)
|
|
return false;
|
|
|
|
const auto &now{ircd::time()};
|
|
for(auto it(pit.first); it != pit.second; )
|
|
{
|
|
const auto &rr{it->second};
|
|
|
|
// Cached entry is too old, ignore and erase
|
|
if(rr.ttl < now)
|
|
{
|
|
it = map.erase(it);
|
|
continue;
|
|
}
|
|
|
|
// Cached entry is a cached error, we set the eptr, but also
|
|
// include the record and increment the count like normal.
|
|
if(!rr.ip4 && !eptr)
|
|
{
|
|
//TODO: we don't cache what the error was, assuming it's
|
|
//TODO: NXDomain can be incorrect and in bad ways downstream...
|
|
static const auto rcode{3}; //NXDomain
|
|
eptr = std::make_exception_ptr(rfc1035::error
|
|
{
|
|
"protocol error #%u (cached) :%s", rcode, rfc1035::rcode.at(rcode)
|
|
});
|
|
}
|
|
|
|
if(count < record.size())
|
|
record.at(count++) = &rr;
|
|
|
|
++it;
|
|
}
|
|
}
|
|
|
|
assert(count || !eptr); // no error if no cache response
|
|
assert(!eptr || count == 1); // if error, should only be one entry.
|
|
|
|
if(count)
|
|
cb(std::move(eptr), hp, vector_view<const rfc1035::record *>(record.data(), count));
|
|
|
|
return count;
|
|
}
|
|
|
|
ircd::rfc1035::record *
|
|
ircd::net::dns::cache::_put(const rfc1035::question &question,
|
|
const rfc1035::answer &answer)
|
|
{
|
|
const auto &host
|
|
{
|
|
rstrip(question.name, '.')
|
|
};
|
|
|
|
assert(!empty(host));
|
|
switch(answer.qtype)
|
|
{
|
|
case 1: // A
|
|
return _cache_answer(cache_A, host, answer);
|
|
|
|
case 33: // SRV
|
|
return _cache_answer(cache_SRV, host, answer);
|
|
|
|
default:
|
|
return nullptr;
|
|
}
|
|
}
|
|
|
|
ircd::rfc1035::record *
|
|
ircd::net::dns::cache::_put_error(const rfc1035::question &question,
|
|
const uint &code)
|
|
{
|
|
const auto &host
|
|
{
|
|
rstrip(question.name, '.')
|
|
};
|
|
|
|
assert(!empty(host));
|
|
switch(question.qtype)
|
|
{
|
|
case 1: // A
|
|
return _cache_error<rfc1035::record::A>(cache_A, host);
|
|
|
|
case 33: // SRV
|
|
return _cache_error<rfc1035::record::SRV>(cache_SRV, host);
|
|
|
|
default:
|
|
return nullptr;
|
|
}
|
|
}
|
|
|
|
template<class Map>
|
|
ircd::rfc1035::record *
|
|
ircd::net::dns::cache::_cache_answer(Map &map,
|
|
const string_view &host,
|
|
const rfc1035::answer &answer)
|
|
{
|
|
auto pit
|
|
{
|
|
map.equal_range(host)
|
|
};
|
|
|
|
auto it(pit.first);
|
|
while(it != pit.second)
|
|
{
|
|
const auto &rr{it->second};
|
|
if(rr == answer)
|
|
it = map.erase(it);
|
|
else
|
|
++it;
|
|
}
|
|
|
|
const auto &iit
|
|
{
|
|
map.emplace_hint(it, host, answer)
|
|
};
|
|
|
|
return &iit->second;
|
|
}
|
|
|
|
template<class T,
|
|
class Map>
|
|
ircd::rfc1035::record *
|
|
ircd::net::dns::cache::_cache_error(Map &map,
|
|
const string_view &host)
|
|
{
|
|
auto pit
|
|
{
|
|
map.equal_range(host)
|
|
};
|
|
|
|
auto it
|
|
{
|
|
pit.first != pit.second?
|
|
map.erase(pit.first, pit.second):
|
|
pit.first
|
|
};
|
|
|
|
T record;
|
|
record.ttl = ircd::time() + seconds(dns::cache::clear_nxdomain).count(); //TODO: code
|
|
it = map.emplace_hint(it, host, record);
|
|
return &it->second;
|
|
}
|
|
|
|
template<class Map>
|
|
bool
|
|
ircd::net::dns::cache::_for_each_(Map &map,
|
|
const closure &closure)
|
|
{
|
|
for(const auto &pair : map)
|
|
{
|
|
const auto &host(pair.first);
|
|
const auto &record(pair.second);
|
|
if(!closure(host, record))
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|