netstack: Remove dnsd

It isn't used anywhere. Relibc has it's own dns resolver.
This commit is contained in:
bjorn3
2025-06-28 16:14:29 +02:00
parent e9b839b484
commit cfef0413e5
4 changed files with 0 additions and 731 deletions
-6
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@@ -3,10 +3,6 @@ name = "redox_netstack"
version = "0.1.0"
edition = "2021"
[[bin]]
name = "dnsd"
path = "src/dnsd/main.rs"
[[bin]]
name = "smolnetd"
path = "src/smolnetd/main.rs"
@@ -21,10 +17,8 @@ redox_event = "0.4.1"
redox-daemon = "0.1.2"
redox_syscall = { version = "0.5", features = ["std"] }
redox-log = "0.1"
dns-parser = "0.7.1"
libredox = { version = "0.1.3", features = ["mkns"] }
anyhow = "1.0.81"
ioslice = "0.6.0"
#redox-scheme = "0.5.0"
redox-scheme = { git = "https://gitlab.redox-os.org/redox-os/redox-scheme.git" }
-97
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@@ -1,97 +0,0 @@
#[macro_use]
extern crate log;
use anyhow::{Context, Result};
use event::EventQueue;
use ioslice::IoSlice;
use libredox::Fd;
use redox_netstack::logger;
use redox_scheme::Socket;
use scheme::Dnsd;
use std::fs::File;
use std::os::unix::io::{FromRawFd, RawFd};
use std::process;
mod scheme;
fn run(daemon: redox_daemon::Daemon) -> Result<()> {
use libredox::flag::*;
let dns_socket = Socket::nonblock("dns").context("failed to open :dns")?;
let time_path = format!("/scheme/time/{}", CLOCK_MONOTONIC);
let time_fd = Fd::open(&time_path, O_RDWR, 0).context("failed to open time")?;
let nameserver_fd = Fd::open(
"/scheme/netcfg/resolv/nameserver",
O_RDWR | O_CREAT | O_NONBLOCK,
0,
)
.context("failed to open nameserver")?;
let event_queue = EventQueue::<EventSource>::new().context("failed to create event queue")?;
event_queue
.subscribe(
dns_socket.inner().raw(),
EventSource::DnsScheme,
event::EventFlags::READ,
)
.context("failed to listen to time events")?;
event_queue
.subscribe(
nameserver_fd.raw(),
EventSource::NameserverScheme,
event::EventFlags::READ,
)
.context("failed to listen to nameserver socket events")?;
event_queue
.subscribe(time_fd.raw(), EventSource::Timer, event::EventFlags::READ)
.context("failed to listen to timer events")?;
let time_file = unsafe { File::from_raw_fd(time_fd.into_raw() as RawFd) };
let mut dnsd = Dnsd::new(dns_socket, time_file, &event_queue);
let new_ns =
libredox::call::mkns(&[IoSlice::new(b"dns")]).expect("dnsd: failed to create namespace");
libredox::call::setrens(new_ns, new_ns).expect("dnsd: failed to enter namespace");
daemon.ready().expect("dnsd: failed to notify parent");
for event_res in event_queue.iter() {
let event = event_res.context("failed to read from event queue")?;
match event.user_data {
EventSource::DnsScheme => {
if !dnsd.on_dns_file_event()? {
break;
}
}
EventSource::NameserverScheme => dnsd.on_nameserver_event()?,
EventSource::Timer => dnsd.on_time_event()?,
EventSource::Other => dnsd.on_unknown_fd_event(event.fd as RawFd)?,
}
}
Ok(())
}
fn main() {
redox_daemon::Daemon::new(move |daemon| {
logger::init_logger("dnsd");
if let Err(err) = run(daemon) {
error!("dnsd: {}", err);
process::exit(1);
}
process::exit(0);
})
.expect("dnsd: failed to daemonize");
}
event::user_data! {
enum EventSource {
DnsScheme,
NameserverScheme,
Timer,
Other,
}
}
-610
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@@ -1,610 +0,0 @@
use std::borrow::ToOwned;
use std::collections::btree_map::Entry;
use std::collections::{BTreeMap, BTreeSet};
use std::collections::{HashMap, VecDeque};
use std::fs::File;
use std::io::{Read, Write};
use std::mem;
use std::net::Ipv4Addr;
use std::os::unix::io::RawFd;
use std::rc::Rc;
use std::str;
use std::str::FromStr;
use libredox::flag;
use redox_scheme::scheme::{IntoTag, Op, OpRead, SchemeSync};
use redox_scheme::{CallerCtx, Id, OpenResult, RequestKind, Response, SignalBehavior};
use syscall::data::TimeSpec;
use syscall::schemev2::NewFdFlags;
use syscall::{self, EAGAIN, ECANCELED, ENOSYS, EWOULDBLOCK};
use syscall::{Error as SyscallError, EventFlags as SyscallEventFlags, Result as SyscallResult};
use event::EventQueue;
use redox_netstack::error::{Error, Result, ResultExt};
use dns_parser::{Builder, Packet as DNSPacket, RRData, ResponseCode};
use dns_parser::{QueryClass, QueryType};
use crate::EventSource;
enum DnsFile {
Resolved { data: Rc<[u8]>, pos: usize },
Waiting { domain: String },
Timeout,
Failed,
}
enum Domain {
Resolved {
data: Rc<[u8]>,
},
Requested {
waiting_fds: BTreeSet<usize>,
socket_fd: RawFd,
},
}
enum DnsParsingResult {
WakeUpFiles(BTreeSet<usize>),
FailFiles(BTreeSet<usize>),
}
struct Domains {
nameserver: Ipv4Addr,
domains: BTreeMap<Rc<str>, Domain>,
requests: BTreeMap<RawFd, Rc<str>>,
resolved_timeouts: VecDeque<(TimeSpec, Rc<str>)>,
requested_timeouts: VecDeque<(TimeSpec, Rc<str>)>,
}
impl Domains {
fn new() -> Domains {
let mut domains = Domains {
nameserver: Ipv4Addr::new(8, 8, 8, 8),
domains: BTreeMap::new(),
requests: BTreeMap::new(),
resolved_timeouts: VecDeque::new(),
requested_timeouts: VecDeque::new(),
};
domains.update_nameserver();
domains
}
pub fn update_nameserver(&mut self) {
if let Ok(mut file) = File::open("/scheme/netcfg/resolv/nameserver") {
let mut nameserver = String::new();
if file.read_to_string(&mut nameserver).is_ok() {
if let Some(line) = nameserver.lines().next() {
if let Ok(ip) = Ipv4Addr::from_str(line) {
trace!("Changing nameserver to {}", ip);
self.nameserver = ip;
}
}
}
}
}
fn request_domain(&mut self, domain: &str, queue: &EventQueue<EventSource>) -> Option<RawFd> {
trace!("Requesting domain {}", domain);
let mut builder = Builder::new_query(1, true);
builder.add_question(domain, QueryType::A, QueryClass::IN);
let packet = builder.build().ok()?;
let udp_fd = libredox::call::open(
&format!("udp:{}:53", self.nameserver),
libredox::flag::O_RDWR | libredox::flag::O_CREAT | libredox::flag::O_NONBLOCK,
0,
)
.ok()?;
if libredox::call::write(udp_fd, &packet) != Ok(packet.len()) {
libredox::call::close(udp_fd).ok()?;
return None;
}
queue
.subscribe(udp_fd, EventSource::Other, event::EventFlags::READ)
.ok()?;
self.requests
.insert(udp_fd as RawFd, domain.to_owned().into());
Some(udp_fd as RawFd)
}
fn on_time_event(
&mut self,
cur_time: &TimeSpec,
queue: &EventQueue<EventSource>,
) -> Result<BTreeSet<usize>> {
while let Some((timeout, domain)) = self.resolved_timeouts.pop_front() {
if timeout.tv_sec > cur_time.tv_sec
|| (timeout.tv_sec == cur_time.tv_sec && timeout.tv_nsec > cur_time.tv_nsec)
{
self.resolved_timeouts.push_front((timeout, domain));
break;
}
trace!("Timing out resolved domain {:?}", domain);
match self.domains.entry(domain) {
Entry::Vacant(_) => {}
Entry::Occupied(e) => {
if let Domain::Resolved { .. } = *e.get() {
e.remove();
}
}
}
}
let mut fds_to_wakeup = BTreeSet::new();
while let Some((timeout, domain)) = self.requested_timeouts.pop_front() {
if timeout.tv_sec > cur_time.tv_sec
|| (timeout.tv_sec == cur_time.tv_sec && timeout.tv_nsec > cur_time.tv_nsec)
{
self.requested_timeouts.push_front((timeout, domain));
break;
}
trace!("Timing out requested domain {:?}", domain);
match self.domains.entry(domain) {
Entry::Vacant(_) => {}
Entry::Occupied(e) => {
if let Domain::Requested { .. } = *e.get() {
if let Domain::Requested {
mut waiting_fds,
socket_fd,
} = e.remove()
{
fds_to_wakeup.append(&mut waiting_fds);
queue.unsubscribe(socket_fd as usize).map_err(|e| {
Error::from_syscall_error(e.into(), "unsubscribe failure")
})?;
let _ = libredox::call::close(socket_fd as usize);
}
}
}
}
}
Ok(fds_to_wakeup)
}
fn on_fd_event(
&mut self,
fd: RawFd,
cur_time: &TimeSpec,
queue: &EventQueue<EventSource>,
) -> Option<DnsParsingResult> {
let e = match self.requests.entry(fd) {
Entry::Vacant(_) => {
return None;
}
Entry::Occupied(e) => e,
};
let mut buf = [0u8; 0x1000];
let readed = libredox::call::read(fd as usize, &mut buf).ok()?;
if readed == 0 {
return None;
}
let pkt = DNSPacket::parse(&buf).ok()?;
if pkt.header.response_code != ResponseCode::NoError || pkt.answers.is_empty() {
if let Some(query) = pkt.questions.iter().next() {
if query.qname.to_string().to_lowercase() == e.get().as_ref() {
queue.unsubscribe(fd as usize).ok()?;
libredox::call::close(fd as usize).ok()?;
let domain = e.remove();
self.requested_timeouts
.retain(|&(_, ref d)| d.as_ref() != domain.as_ref());
if let Entry::Occupied(e) = self.domains.entry(domain) {
let domain_data = e.remove();
return if let Domain::Requested { waiting_fds, .. } = domain_data {
Some(DnsParsingResult::FailFiles(waiting_fds))
} else {
None
};
}
}
}
return None;
}
let mut result = String::new();
for answer in pkt.answers {
if answer.name.to_string().to_lowercase() != e.get().as_ref() {
continue;
}
if let RRData::A(ip) = answer.data {
result += &format!("{}\n", ip);
}
}
if result.is_empty() {
return None;
}
let data = Rc::from(result.into_bytes());
queue.unsubscribe(fd as usize).ok()?;
libredox::call::close(fd as usize).ok()?;
let domain = e.remove();
let mut domain_data = Domain::Resolved { data };
trace!("On FD event {} {} resolved", fd, domain);
let mut resolved_timeout = *cur_time;
resolved_timeout.tv_sec += Dnsd::RESOLVED_TIMEOUT_S;
self.resolved_timeouts
.push_back((resolved_timeout, Rc::clone(&domain)));
self.requested_timeouts
.retain(|&(_, ref d)| d.as_ref() != domain.as_ref());
match self.domains.entry(domain) {
Entry::Vacant(e) => {
e.insert(domain_data);
None
}
Entry::Occupied(mut e) => {
mem::swap(e.get_mut(), &mut domain_data);
if let Domain::Requested { waiting_fds, .. } = domain_data {
Some(DnsParsingResult::WakeUpFiles(waiting_fds))
} else {
None
}
}
}
}
fn file_from_domain(
&mut self,
domain: &str,
fd: usize,
cur_time: &TimeSpec,
queue: &EventQueue<EventSource>,
) -> DnsFile {
if let Some(domain_data) = self.domains.get_mut(domain) {
match *domain_data {
Domain::Resolved { ref data } => DnsFile::Resolved {
data: Rc::clone(data),
pos: 0,
},
Domain::Requested {
ref mut waiting_fds,
..
} => {
waiting_fds.insert(fd);
DnsFile::Waiting {
domain: domain.to_owned(),
}
}
}
} else {
if let Some(socket_fd) = self.request_domain(domain, queue) {
let mut waiting_fds = BTreeSet::new();
let domain = domain.to_owned().into();
waiting_fds.insert(fd);
self.domains.insert(
Rc::clone(&domain),
Domain::Requested {
waiting_fds,
socket_fd,
},
);
let mut timeout = *cur_time;
timeout.tv_sec += Dnsd::REQUEST_TIMEOUT_S;
self.requested_timeouts.push_back((timeout, domain));
}
DnsFile::Waiting {
domain: domain.to_owned(),
}
}
}
fn unwait_fd(&mut self, domain: &str, fd: usize) {
if let Some(domain_data) = self.domains.get_mut(domain) {
if let Domain::Requested {
ref mut waiting_fds,
..
} = *domain_data
{
waiting_fds.remove(&fd);
}
}
}
}
pub struct Dnsd<'q> {
scheme_socket: redox_scheme::Socket,
time_file: File,
queue: &'q EventQueue<EventSource>,
files: BTreeMap<usize, DnsFile>,
domains: Domains,
blocked_ids: HashMap<Id, (CallerCtx, OpRead)>,
blocked_fds: HashMap<usize, Vec<Id>>,
next_fd: usize,
}
impl<'q> Dnsd<'q> {
const RESOLVED_TIMEOUT_S: i64 = 5 * 60;
const REQUEST_TIMEOUT_S: i64 = 30;
const TIME_EVENT_TIMEOUT_S: i64 = 5;
pub fn new(
scheme_socket: redox_scheme::Socket,
time_file: File,
queue: &'q EventQueue<EventSource>,
) -> Self {
Dnsd {
scheme_socket,
time_file,
queue,
files: BTreeMap::new(),
domains: Domains::new(),
blocked_ids: HashMap::new(),
blocked_fds: HashMap::new(),
next_fd: 1,
}
}
pub fn on_time_event(&mut self) -> Result<()> {
let mut time = TimeSpec::default();
if self.time_file.read(&mut time)? < mem::size_of::<TimeSpec>() {
return Err(Error::from_syscall_error(
syscall::Error::new(syscall::EBADF),
"Can't read current time",
));
}
let fds_to_wakeup = self.domains.on_time_event(&time, self.queue)?;
if !fds_to_wakeup.is_empty() {
for fd in &fds_to_wakeup {
if let Some(file) = self.files.get_mut(fd) {
*file = DnsFile::Timeout;
}
}
self.wakeup_fds(&fds_to_wakeup)?;
}
time.tv_sec += Dnsd::TIME_EVENT_TIMEOUT_S;
self.time_file
.write_all(&time)
.map_err(|e| Error::from_io_error(e, "Failed to write to time file"))?;
Ok(())
}
pub fn on_dns_file_event(&mut self) -> Result<bool> {
loop {
let req = match self.scheme_socket.next_request(SignalBehavior::Restart) {
Ok(None) => {
//TODO: Cleanup must occur
return Ok(false);
}
Ok(Some(req)) => req,
Err(err) if err.errno == EWOULDBLOCK || err.errno == EAGAIN => {
return Ok(true);
}
Err(err) => return Err(err).context("scheme read error"),
};
let req = match req.kind() {
RequestKind::Call(call) => call,
RequestKind::OnClose { id } => {
self.on_close(id);
continue;
}
RequestKind::Cancellation(req) => {
if let Some((_, op)) = self.blocked_ids.remove(&req.id) {
if let Some(blocked) = self.blocked_fds.get_mut(&op.fd) {
blocked.retain(|id| *id != req.id);
}
self.scheme_socket
.write_response(Response::err(ECANCELED, op), SignalBehavior::Restart)
.context("scheme write fail")?;
}
continue;
}
_ => continue,
};
let ctx = req.caller();
let resp = match req.op() {
Err(req) => Response::err(ENOSYS, req),
Ok(Op::Read(mut op)) => {
let fd = op.fd;
// TODO: nonblock read flag to bypass blocking
let res = self.read(fd, op.buf(), 0, 0, &ctx);
if res == Err(SyscallError::new(EWOULDBLOCK)) {
let id = op.req_id();
self.blocked_ids.insert(id, (ctx, op));
self.blocked_fds.entry(fd).or_default().push(id);
continue;
} else {
Response::new(res, op)
}
}
Ok(op) => op.handle_sync(ctx, self),
};
self.scheme_socket
.write_response(resp, SignalBehavior::Restart)
.context("scheme write fail")?;
}
}
pub fn on_unknown_fd_event(&mut self, fd: RawFd) -> Result<()> {
trace!("Unknown fd event {}", fd);
let cur_time = libredox::call::clock_gettime(libredox::flag::CLOCK_MONOTONIC)
.map_err(|e| Error::from_syscall_error(e.into(), "Can't get time"))?;
// TODO
let cur_time = TimeSpec {
tv_sec: cur_time.tv_sec,
tv_nsec: cur_time.tv_nsec as _,
};
match self.domains.on_fd_event(fd, &cur_time, self.queue) {
Some(DnsParsingResult::FailFiles(fds_to_fail)) => {
for fd in &fds_to_fail {
if let Some(file) = self.files.get_mut(fd) {
*file = DnsFile::Failed;
}
}
self.wakeup_fds(&fds_to_fail)?;
}
Some(DnsParsingResult::WakeUpFiles(fds_to_wakeup)) => {
self.wakeup_fds(&fds_to_wakeup)?;
}
None => {}
}
Ok(())
}
pub fn on_nameserver_event(&mut self) -> Result<()> {
self.domains.update_nameserver();
Ok(())
}
fn wakeup_fds(&mut self, fds_to_wakeup: &BTreeSet<usize>) -> Result<()> {
for fd in fds_to_wakeup {
let Some(affected) = self.blocked_fds.remove(&fd) else {
continue;
};
for id in affected {
let Some((ctx, mut op)) = self.blocked_ids.remove(&id) else {
continue;
};
// TODO: deduplicate code
let fd = op.fd;
// TODO: nonblock read flag to bypass blocking
let res = self.read(fd, op.buf(), 0, 0, &ctx);
let resp = if res == Err(SyscallError::new(EWOULDBLOCK)) {
self.blocked_ids.insert(id, (ctx, op));
self.blocked_fds.entry(fd).or_default().push(id);
continue;
} else {
Response::new(res, op)
};
self.scheme_socket
.write_response(resp, SignalBehavior::Restart)
.context("scheme write fail")?;
}
}
Ok(())
}
fn validate_domain(domain: &str) -> bool {
if domain.len() > 256 {
return false;
}
for part in domain.split('.') {
if part.len() >= 63 {
return false;
}
}
true
}
}
impl Dnsd<'_> {
fn on_close(&mut self, fd: usize) {
trace!("Close {}", fd);
let Some(file) = self.files.get_mut(&fd) else {
return;
};
if let DnsFile::Waiting { ref domain } = *file {
self.domains.unwait_fd(domain, fd);
}
self.files.remove(&fd);
}
}
impl SchemeSync for Dnsd<'_> {
fn open(&mut self, url: &str, _flags: usize, _ctx: &CallerCtx) -> SyscallResult<OpenResult> {
let domain = url.to_lowercase();
if domain.is_empty() || !Dnsd::validate_domain(&domain) {
return Err(SyscallError::new(syscall::EINVAL));
}
let fd = self.next_fd;
self.next_fd += 1;
let cur_time = libredox::call::clock_gettime(flag::CLOCK_MONOTONIC)?;
let dns_file = self.domains.file_from_domain(
&domain,
fd,
&TimeSpec {
tv_sec: cur_time.tv_sec,
tv_nsec: cur_time.tv_nsec as i32,
},
self.queue,
);
self.files.insert(fd, dns_file);
trace!("Open {} {}", &domain, fd);
Ok(OpenResult::ThisScheme {
number: fd,
flags: NewFdFlags::empty(),
})
}
fn write(
&mut self,
_fd: usize,
_buf: &[u8],
_off: u64,
_flags: u32,
_ctx: &CallerCtx,
) -> SyscallResult<usize> {
Err(SyscallError::new(syscall::EINVAL))
}
fn read(
&mut self,
fd: usize,
buf: &mut [u8],
_off: u64,
_flags: u32,
_ctx: &CallerCtx,
) -> SyscallResult<usize> {
trace!("Read {}", fd);
let file = self
.files
.get_mut(&fd)
.ok_or_else(|| SyscallError::new(syscall::EBADF))?;
let cur_time = libredox::call::clock_gettime(flag::CLOCK_MONOTONIC)?;
if let DnsFile::Waiting { ref domain } = *file {
*file = self.domains.file_from_domain(
domain,
fd,
&TimeSpec {
tv_sec: cur_time.tv_sec,
tv_nsec: cur_time.tv_nsec as i32,
},
self.queue,
);
}
match *file {
DnsFile::Resolved {
ref data,
ref mut pos,
} => {
let mut i = 0;
while i < buf.len() && *pos < data.len() {
buf[i] = data[*pos];
i += 1;
*pos += 1;
}
Ok(i)
}
DnsFile::Waiting { .. } => Err(SyscallError::new(syscall::EWOULDBLOCK)),
DnsFile::Timeout => Err(SyscallError::new(syscall::ETIMEDOUT)),
DnsFile::Failed => Err(SyscallError::new(syscall::ENODATA)),
}
}
fn fevent(
&mut self,
_fd: usize,
_events: SyscallEventFlags,
_ctx: &CallerCtx,
) -> SyscallResult<SyscallEventFlags> {
Ok(SyscallEventFlags::empty())
}
fn fsync(&mut self, _fd: usize, _ctx: &CallerCtx) -> SyscallResult<()> {
Ok(())
}
}