RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-25 16:27:35 +00:00
Code Issues Activity Actions

LookupServer: Cache successful DNS lookup responses for 1 minute

Browse source 
This reduces DNS traffic spam during web browsing. We can definitely do
a lot better here, this is just a very low-hanging fruit.
This commit is contained in:
Andreas Kling 2019-10-16 12:10:16 +02:00
parent 005b416639
commit 3a4da5aa05
1 changed files with 17 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

17
Servers/LookupServer/main.cpp
View file

@ -16,6 +16,7 @@
#include <sys/select.h> #include <sys/select.h>
#include <sys/socket.h> #include <sys/socket.h>
#include <sys/time.h> #include <sys/time.h>
#include <time.h>
#include <unistd.h> #include <unistd.h>
#define T_A 1 #define T_A 1
@ -27,6 +28,13 @@
#define C_IN 1 #define C_IN 1
struct CachedLookup {
time_t timestamp { 0 };
unsigned short record_type { 0 };
Vector<String> responses;
};
static HashMap<String, CachedLookup> lookup_cache;
static HashMap<String, String> dns_custom_hostnames; static HashMap<String, String> dns_custom_hostnames;
static Vector<String> lookup(const String& hostname, bool& did_timeout, const String& DNS_IP, unsigned short record_type); static Vector<String> lookup(const String& hostname, bool& did_timeout, const String& DNS_IP, unsigned short record_type);
@ -207,6 +215,14 @@ static u16 get_next_id()
Vector<String> lookup(const String& hostname, bool& did_timeout, const String& DNS_IP, unsigned short record_type) Vector<String> lookup(const String& hostname, bool& did_timeout, const String& DNS_IP, unsigned short record_type)
{ {
if (auto it = lookup_cache.find(hostname); it != lookup_cache.end()) {
auto& cached_lookup = it->value;
if (cached_lookup.record_type == record_type && cached_lookup.timestamp < (time(nullptr) + 60)) {
return it->value.responses;
}
lookup_cache.remove(it);
}
DNSPacket request_header; DNSPacket request_header;
request_header.set_id(get_next_id()); request_header.set_id(get_next_id());
request_header.set_is_query(); request_header.set_is_query();
@ -335,6 +351,7 @@ Vector<String> lookup(const String& hostname, bool& did_timeout, const String& D
// FIXME: Parse some other record types perhaps? // FIXME: Parse some other record types perhaps?
} }
lookup_cache.set(hostname, { time(nullptr), record_type, addresses });
return addresses; return addresses;
} }