RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-27 03:57:44 +00:00
Code Issues Activity Actions

LookupServer: Switch to LibIPC :^)

Browse source 
The ad-hoc IPC we were doing with LookupServer was kinda gross. With this,
LookupServer is a regular IPC server. In the future, we want to add more APIs
for LookupServer to talk to its clients (such as DHCPClient telling LookupServer
about the DNS server discovered via DHCP, and DNS-SD client browsing for
services), which calls for a more expressive IPC format; this is what LibIPC is
perfect for.

While the LookupServer side is using the regular LibIPC mechanics and patterns,
the LibC side has to hand-roll LibIPC format serialization without actually
using LibIPC. We might be able to get rid of this in the future, but for now it
has to be like that. The good news is the format is not that bad at all.
This commit is contained in:
Sergey Bugaev 2021-02-05 13:20:05 +03:00 • committed by Andreas Kling
parent 314f966745
commit 547130584c
8 changed files with 273 additions and 74 deletions
Download patch file Download diff file Expand all files Collapse all files

69
Userland/Services/LookupServer/LookupServer.cpp
View file

@ -25,6 +25,7 @@
*/
#include "LookupServer.h"
#include "ClientConnection.h"
#include "DNSRequest.h"
#include "DNSResponse.h"
#include <AK/ByteBuffer.h>
@ -43,8 +44,19 @@
namespace LookupServer {
static LookupServer* s_the;
LookupServer& LookupServer::the()
{
ASSERT(s_the);
return *s_the;
}
LookupServer::LookupServer()
{
ASSERT(s_the == nullptr);
s_the = this;
auto config = Core::ConfigFile::get_for_system("LookupServer");
dbgln("Using network config file at {}", config->file_name());
m_nameservers = config->read_entry("DNS", "Nameservers", "1.1.1.1,1.0.0.1").split(',');
@ -54,13 +66,13 @@ LookupServer::LookupServer()
m_local_server = Core::LocalServer::construct(this);
m_local_server->on_ready_to_accept = [this]() {
auto socket = m_local_server->accept();
if (!socket)
if (!socket) {
dbgln("Failed to accept a client connection");
return;
socket->on_ready_to_read = [this, socket]() {
service_client(*socket);
NonnullRefPtr keeper = *socket;
const_cast<Core::LocalSocket&>(*socket).on_ready_to_read = [] {};
};
}
static int s_next_client_id = 0;
int client_id = ++s_next_client_id;
IPC::new_client_connection<ClientConnection>(socket.release_nonnull(), client_id);
};
bool ok = m_local_server->take_over_from_system_server();
ASSERT(ok);
@ -101,32 +113,17 @@ void LookupServer::load_etc_hosts()
}
}
void LookupServer::service_client(NonnullRefPtr<Core::LocalSocket> socket)
Vector<String> LookupServer::lookup(const String& name, unsigned short record_type)
{
u8 client_buffer[1024];
int nrecv = socket->read(client_buffer, sizeof(client_buffer) - 1);
if (nrecv < 0) {
perror("read");
return;
}
client_buffer[nrecv] = '\0';
char lookup_type = client_buffer[0];
if (lookup_type != 'L' && lookup_type != 'R') {
dbgln("Invalid lookup_type '{}'", lookup_type);
return;
}
auto hostname = String((const char*)client_buffer + 1, nrecv - 1, Chomp);
#if LOOKUPSERVER_DEBUG
dbgln("Got request for '{}'", hostname);
dbgln("Got request for '{}'", name);
#endif
Vector<String> responses;
if (auto known_host = m_etc_hosts.get(hostname); known_host.has_value()) {
if (auto known_host = m_etc_hosts.get(name); known_host.has_value()) {
responses.append(known_host.value());
} else if (!hostname.is_empty()) {
} else if (!name.is_empty()) {
for (auto& nameserver : m_nameservers) {
#if LOOKUPSERVER_DEBUG
dbgln("Doing lookup using nameserver '{}'", nameserver);
@ -134,10 +131,7 @@ void LookupServer::service_client(NonnullRefPtr<Core::LocalSocket> socket)
bool did_get_response = false;
int retries = 3;
do {
if (lookup_type == 'L')
responses = lookup(hostname, nameserver, did_get_response, T_A);
else if (lookup_type == 'R')
responses = lookup(hostname, nameserver, did_get_response, T_PTR);
responses = lookup(name, nameserver, did_get_response, record_type);
if (did_get_response)
break;
} while (--retries);
@ -152,24 +146,11 @@ void LookupServer::service_client(NonnullRefPtr<Core::LocalSocket> socket)
}
if (responses.is_empty()) {
fprintf(stderr, "LookupServer: Tried all nameservers but never got a response :(\n");
return;
return {};
}
}
if (responses.is_empty()) {
int nsent = socket->write("Not found.\n");
if (nsent < 0)
perror("write");
return;
}
for (auto& response : responses) {
auto line = String::formatted("{}\n", response);
int nsent = socket->write(line);
if (nsent < 0) {
perror("write");
break;
}
}
return move(responses);
}
Vector<String> LookupServer::lookup(const String& hostname, const String& nameserver, bool& did_get_response, unsigned short record_type, ShouldRandomizeCase should_randomize_case)