gimlet-inspector: first draft.

Cargo.toml

@@ -116,6 +116,7 @@ zip = { version = "0.6", default-features = false, features = ["bzip2"] }
 attest-data = { git = "https://github.com/oxidecomputer/dice-util", default-features = false, version = "0.1.0" }
 dice-mfg-msgs = { git = "https://github.com/oxidecomputer/dice-util", default-features = false, version = "0.2.1" }
 gateway-messages = { git = "https://github.com/oxidecomputer/management-gateway-service", default-features = false, features = ["smoltcp"] }
+gimlet-inspector-protocol = { git = "https://github.com/oxidecomputer/gimlet-inspector-protocol", version = "0.1.0", branch = "initial-protocol" }
 hif = { git = "https://github.com/oxidecomputer/hif", default-features = false }
 humpty = { git = "https://github.com/oxidecomputer/humpty", default-features = false, version = "0.1.3" }
 hubtools = { git = "https://github.com/oxidecomputer/hubtools", default-features = false, version = "0.4.1" }

app/gimlet/base.toml

@@ -154,6 +154,16 @@ copy-to-archive = ["register_defs"]
 fpga_image = "fpga-b.bin"
 register_defs = "gimlet-regs-b.json"
 
+[tasks.gimlet_inspector]
+name = "task-gimlet-inspector"
+priority = 6
+features = ["vlan"]
+max-sizes = {flash = 65536, ram = 8192 }
+stacksize = 1600
+start = true
+task-slots = ["net", {seq = "gimlet_seq"}]
+notifications = ["socket"]
+
 [tasks.hash_driver]
 name = "drv-stm32h7-hash-server"
 features = ["h753"]
@@ -1271,6 +1281,13 @@ port = 11113
 tx = { packets = 3, bytes = 1024 }
 rx = { packets = 3, bytes = 1024 }
 
+[config.net.sockets.inspector]
+kind = "udp"
+owner = {name = "gimlet_inspector", notification = "socket"}
+port = 23547
+tx = { packets = 3, bytes = 1024 }
+rx = { packets = 3, bytes = 512 }
+
 [config.sprot]
 # ROT_IRQ (af=0 for GPIO, af=15 when EXTI is implemneted)
 rot_irq = { port = "E", pin = 3, af = 0}

task/gimlet-inspector/Cargo.toml

@@ -0,0 +1,28 @@
+[package]
+name = "task-gimlet-inspector"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+serde = { workspace = true }
+hubpack = { workspace = true }
+gimlet-inspector-protocol = { workspace = true }
+
+task-net-api = { path = "../net-api" }
+drv-gimlet-seq-api = { path = "../../drv/gimlet-seq-api" }
+userlib = { path = "../../sys/userlib", features = ["panic-messages"] }
+
+
+[build-dependencies]
+build-util = { path = "../../build/util" }
+
+[features]
+vlan = ["task-net-api/vlan"]
+
+# This section is here to discourage RLS/rust-analyzer from doing test builds,
+# since test builds don't work for cross compilation.
+[[bin]]
+name = "task-gimlet-inspector"
+test = false
+doctest = false
+bench = false

task/gimlet-inspector/build.rs

@@ -0,0 +1,8 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    build_util::build_notifications()?;
+    Ok(())
+}

task/gimlet-inspector/src/main.rs

@@ -0,0 +1,134 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+//! The Gimlet Inspector provides a deliberately limited set of IPCs over the
+//! network, for extracting diagnostic data from a live system. This is intended
+//! to supplement the more general `dump_agent`.
+
+#![no_std]
+#![no_main]
+
+use task_net_api::*;
+use userlib::*;
+use gimlet_inspector_protocol::{Request, Query, SequencerRegistersResponse};
+use drv_gimlet_seq_api::{Sequencer, SeqError};
+use hubpack::SerializedSize;
+
+task_slot!(NET, net);
+task_slot!(SEQ, seq);
+
+// Increase this if a new message requires a larger trailer.
+const MAX_REQ_TRAILER_SIZE: usize = 0;
+
+#[export_name = "main"]
+fn main() -> ! {
+    // Look up our peer task IDs and make clients.
+    let net = Net::from(NET.get_task_id());
+    let seq = Sequencer::from(SEQ.get_task_id());
+
+    const SOCKET: SocketName = SocketName::inspector;
+
+    loop {
+        // These buffers are currently kept kinda small because our protocol
+        // messages are small.
+        let mut rx_data_buf = [0u8; Request::MAX_SIZE + MAX_REQ_TRAILER_SIZE];
+        let mut tx_data_buf = [0u8; 128];
+
+        match net.recv_packet(
+            SOCKET,
+            LargePayloadBehavior::Discard,
+            &mut rx_data_buf,
+        ) {
+            Ok(mut meta) => {
+                let Ok((request, _trailer)) = hubpack::deserialize::<Request>(&rx_data_buf) else {
+                    // We ignore malformatted, truncated, etc. packets.
+                    continue;
+                };
+
+                match request {
+                    Request::V0(Query::SequencerRegisters) => {
+                        let (resp, trailer) = match seq.read_fpga_regs() {
+                            Ok(regs) => {
+                                (SequencerRegistersResponse::Success, Some(regs))
+                            }
+                            Err(SeqError::ServerRestarted) => {
+                                (SequencerRegistersResponse::SequencerTaskDead, None)
+                            }
+                            Err(_) => {
+                                // The SeqError type represents a mashing
+                                // together of all possible errors for all
+                                // possible sequencer IPC operations. The only
+                                // one we _expect_ here is ReadRegsFailed.
+                                (SequencerRegistersResponse::SequencerReadRegsFailed, None)
+                            }
+                        };
+                        let mut len = hubpack::serialize(&mut tx_data_buf, &resp)
+                            .unwrap_lite();
+                        if let Some(t) = trailer {
+                            tx_data_buf[len..len + t.len()].copy_from_slice(&t);
+                            len += t.len();
+                        }
+                        meta.size = len as u32;
+                    }
+                }
+
+                // With the response packet prepared, we may need to attempt
+                // sending more than once.
+                loop {
+                    match net.send_packet(
+                        SOCKET,
+                        meta,
+                        &tx_data_buf[0..(meta.size as usize)],
+                    ) {
+                        Ok(()) => break,
+                        // If `net` just restarted, immediately retry our send.
+                        Err(SendError::ServerRestarted) => continue,
+                        // If our tx queue is full, wait for space. This is the
+                        // same notification we get for incoming packets, so we
+                        // might spuriously wake up due to an incoming packet
+                        // (which we can't service anyway because we are still
+                        // waiting to respond to a previous request); once we
+                        // finally succeed in sending we'll peel any queued
+                        // packets off our recv queue at the top of our main
+                        // loop.
+                        Err(SendError::QueueFull) => {
+                            sys_recv_closed(
+                                &mut [],
+                                notifications::SOCKET_MASK,
+                                TaskId::KERNEL,
+                            )
+                            .unwrap_lite();
+                        }
+                        // These errors should be impossible if we're configured
+                        // correctly.
+                        Err(SendError::NotYours | SendError::InvalidVLan) => {
+                            unreachable!()
+                        }
+                        // Unclear under what conditions we could se `Other` -
+                        // just panic for now? At the time of this writing
+                        // `Other` should only come back if the destination
+                        // address in `meta` is bogus or our socket is closed,
+                        // neither of which should be possible here.
+                        Err(SendError::Other) => panic!(),
+                    }
+                }
+            }
+            Err(RecvError::QueueEmpty) => {
+                // Our incoming queue is empty. Wait for more packets.
+                sys_recv_closed(
+                    &mut [],
+                    notifications::SOCKET_MASK,
+                    TaskId::KERNEL,
+                )
+                .unwrap_lite();
+            }
+            Err(RecvError::ServerRestarted) => {
+                // `net` restarted (probably due to the watchdog); just retry.
+            }
+            Err(RecvError::NotYours | RecvError::Other) => panic!(),
+        }
+    }
+}
+
+include!(concat!(env!("OUT_DIR"), "/notifications.rs"));