server/suser.rs

   1 // Copyright 2021 Ian Jackson and contributors to Hippotat
   2 // SPDX-License-Identifier: GPL-3.0-or-later
   3 // There is NO WARRANTY.
   4
   5 use super::*;
   6
   7 #[derive(Debug)]
   8 pub struct User {
   9   pub ic: Arc<InstanceConfig>,
  10   pub web: mpsc::Sender<WebRequest>,
  11   pub route: mpsc::Sender<RoutedPacket>,
  12 }
  13
  14 pub async fn run(global: Arc<Global>,
  15                  ic: Arc<InstanceConfig>,
  16                  mut web: mpsc::Receiver<WebRequest>,
  17                  mut routed: mpsc::Receiver<RoutedPacket>)
  18                  -> Result<Void, AE>
  19 {
  20   struct Outstanding {
  21     reply_to: oneshot::Sender<WebResponse>,
  22     oi: OutstandingInner,
  23   }
  24   #[derive(Debug)]
  25   struct OutstandingInner {
  26     deadline: Instant,
  27     target_requests_outstanding: u32,
  28     max_batch_down: u32,
  29   }
  30   let mut outstanding: VecDeque<Outstanding> = default();
  31   let mut downbound: PacketQueue<RoutedPacketData> = default();
  32
  33   let try_send_response = |
  34     reply_to: oneshot::Sender<WebResponse>,
  35     response: WebResponse
  36   | {
  37     reply_to.send(response)
  38       .unwrap_or_else(|_: WebResponse| {
  39         /* oh dear */
  40         error!("unable to send response back to webserver! user={}",
  41                &ic.link.client);
  42       });
  43   };
  44
  45   loop {
  46     let eff_max_batch_down = outstanding
  47       .iter()
  48       .map(|o| o.oi.max_batch_down)
  49       .min()
  50       .unwrap_or(ic.max_batch_down)
  51       .sat();
  52
  53     if let Some(req) = {
  54       if ! downbound.is_empty() {
  55         outstanding.pop_front()
  56       } else if let Some((i,_)) = outstanding.iter().enumerate().find({
  57         |(_,o)| outstanding.len() > o.oi.target_requests_outstanding.sat()
  58         // xxx need timeout-based return too
  59       }) {
  60         Some(outstanding.remove(i).unwrap())
  61       } else {
  62         None
  63       }
  64     } {
  65       let mut build: FrameQueueBuf = default();
  66
  67       loop {
  68         let next = if let Some(n) = downbound.peek_front() { n }
  69                    else { break };
  70         // Don't add 1 for the ESC since we will strip one
  71         if build.len() + next.len() >= eff_max_batch_down { break }
  72         build.esc_push(downbound.pop_front().unwrap());
  73       }
  74       if ! build.is_empty() {
  75         // skip leading ESC
  76         build.advance(1);
  77       }
  78
  79       let response = WebResponse {
  80         data: Ok(build),
  81         warnings: default(),
  82       };
  83
  84       try_send_response(req.reply_to, response);
  85     }
  86
  87     let max = usize::saturating_mul(
  88       ic.max_requests_outstanding.sat(),
  89       eff_max_batch_down,
  90     ).saturating_add(1 /* one boundary SLIP_ESC which we'll trim */);
  91
  92     while downbound.total_len() > max {
  93       let _ = downbound.pop_front();
  94     }
  95
  96     select!{
  97       biased;
  98
  99       data = routed.recv() =>
 100       {
 101         let data = data.ok_or_else(|| anyhow!("routers shut down!"))?;
 102         downbound.push_back(data.data);
 103       },
 104
 105       req = web.recv() =>
 106       {
 107         let WebRequest {
 108           initial, initial_remaining, length_hint, mut body,
 109           boundary_finder,
 110           reply_to, conn, mut warnings, may_route,
 111         } = req.ok_or_else(|| anyhow!("webservers all shut down!"))?;
 112
 113         match async {
 114
 115           let initial_used = initial.len() - initial_remaining;
 116
 117           let whole_request = read_limited_bytes(
 118             ic.max_batch_up.sat(),
 119             initial,
 120             length_hint,
 121             &mut body
 122           ).await.context("read request body")?;
 123
 124           let (meta, mut comps) =
 125             multipart::ComponentIterator::resume_mid_component(
 126               &whole_request[initial_used..],
 127               boundary_finder
 128             ).context("resume parsing body, after auth checks")?;
 129
 130           let mut meta = MetadataFieldIterator::new(&meta);
 131
 132           macro_rules! meta {
 133             { $v:ident, ( $( $badcmp:tt )? ), $ret:expr,
 134               let $server:ident, $client:ident $($code:tt)*
 135             } => {
 136               let $v = (||{
 137                 let $server = ic.$v;
 138                 let $client $($code)*
 139                 $(
 140                   if $client $badcmp $server {
 141                     throw!(anyhow!("mismatch: client={:?} {} server={:?}",
 142                                    $client, stringify!($badcmp), $server));
 143                   }
 144                 )?
 145                 Ok::<_,AE>($ret)
 146               })().context(stringify!($v))?;
 147               //dbg!(&$v);
 148             }
 149           }
 150           meta!{
 151             target_requests_outstanding, ( != ), client,
 152             let server, client: u32 = meta.need_parse()?;
 153           }
 154           meta!{
 155             http_timeout, ( > ), client,
 156             let server, client = Duration::from_secs(meta.need_parse()?);
 157           }
 158           meta!{
 159             mtu, ( != ), client,
 160             let server, client: u32 = meta.parse()?.unwrap_or(server);
 161           }
 162           meta!{
 163             max_batch_down, (), min(client, server),
 164             let server, client: u32 = meta.parse()?.unwrap_or(server);
 165           }
 166           meta!{
 167             max_batch_up, ( > ), client,
 168             let server, client = meta.parse()?.unwrap_or(server);
 169           }
 170           let _ = max_batch_up; // we don't use this further
 171
 172           while let Some(comp) = comps.next(&mut warnings, PartName::d)? {
 173             if comp.name != PartName::d {
 174               warnings.add(&format_args!("unexpected part {:?}", comp.name))?;
 175             }
 176             slip::processn(Mime2Slip, mtu, comp.payload, |header| {
 177               let saddr = ip_packet_addr::<false>(header)?;
 178               if saddr != ic.link.client.0 { throw!(PE::Src(saddr)) }
 179               let daddr = ip_packet_addr::<true>(header)?;
 180               Ok(daddr)
 181             }, |(daddr,packet)| route_packet(
 182               &global, &conn, Some(&ic.link.client), daddr,
 183               packet, may_route.clone(),
 184             ).map(Ok),
 185               |e| Ok::<_,SlipFramesError<_>>({ warnings.add(&e)?; })
 186             ).await?;
 187           }
 188
 189           let deadline = Instant::now() + http_timeout;
 190
 191           let oi = OutstandingInner {
 192             target_requests_outstanding,
 193             max_batch_down,
 194             deadline,
 195           };
 196           Ok::<_,AE>(oi)
 197         }.await {
 198           Ok(oi) => outstanding.push_back(Outstanding { reply_to, oi }),
 199           Err(e) => {
 200             try_send_response(reply_to, WebResponse {
 201               data: Err(e),
 202               warnings,
 203             });
 204           },
 205         }
 206       }
 207     }
 208   }
 209 }