From ca7fafd9d8b228bd8a1a46a4defbda311b244095 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stanis=C5=82aw=20Pitucha?= <viraptor@gmail.com>
Date: Wed, 1 Sep 2021 21:23:45 +1000
Subject: [PATCH] Add message receiving usdts

This requires the systemtap development package as well as dtrace tool
to be present during building.

The specific notifications are configured in radicle_link.d and the
names can be used to filter the results. Currently the notifications
work only on Linux, but a different crate can be used for the same
result on MacOS.

The result can be tested on a running seed with:

```
sudo bpftrace -p $(pgrep -f radicle-seed-node) -e '
  usdt:*/radicle-seed-node:radicleusdt:have_recv {
    printf("have, peer %s, urn %s\n", str(arg0), str(arg1));
  }
  usdt:*/radicle-seed-node:radicleusdt:want_recv {
    printf("want, peer %s, urn %s\n", str(arg0), str(arg1));
  }'
```
---
 librad/Cargo.toml              |  8 ++++++++
 librad/build.rs                |  6 ++++++
 librad/radicle_link.d          |  4 ++++
 librad/src/lib.rs              |  5 +++++
 librad/src/net/peer/storage.rs | 23 +++++++++++++++++++++++
 5 files changed, 46 insertions(+)
 create mode 100644 librad/build.rs
 create mode 100644 librad/radicle_link.d

diff --git a/librad/Cargo.toml b/librad/Cargo.toml
index f98a82837..00a595784 100644
--- a/librad/Cargo.toml
+++ b/librad/Cargo.toml
@@ -61,6 +61,11 @@ uuid = { version = "0.8", features = ["v4"] }
 webpki = "0.21"
 xorf = "0.7"
 
+[build-dependencies.sonde]
+git = "https://github.com/viraptor/sonde-rs"
+rev = "88c3b872eaa7fdfe6ffbef34e1c920d4c9401544"
+optional = true
+
 [dependencies.deadpool]
 version = "0.7"
 default-features = false
@@ -143,3 +148,6 @@ features = ["serde"]
 [dependencies.zeroize]
 version = "1.1"
 features = ["zeroize_derive"]
+
+[features]
+usdt = ["sonde"]
diff --git a/librad/build.rs b/librad/build.rs
new file mode 100644
index 000000000..2a3babc69
--- /dev/null
+++ b/librad/build.rs
@@ -0,0 +1,6 @@
+fn main() {
+    #[cfg(feature = "usdt")]
+    sonde::Builder::new()
+        .file("./radicle_link.d")
+        .compile();
+}
diff --git a/librad/radicle_link.d b/librad/radicle_link.d
new file mode 100644
index 000000000..1b5e1c381
--- /dev/null
+++ b/librad/radicle_link.d
@@ -0,0 +1,4 @@
+provider radicle_link {
+    probe have_recv(char*, char*);
+    probe want_recv(char*, char*);
+};
diff --git a/librad/src/lib.rs b/librad/src/lib.rs
index 12c728b25..da316b9ea 100644
--- a/librad/src/lib.rs
+++ b/librad/src/lib.rs
@@ -18,6 +18,11 @@
 #![feature(try_trait_v2)]
 #![feature(control_flow_enum)]
 
+#[cfg(feature = "usdt")]
+pub mod usdt {
+    include!(env!("SONDE_RUST_API_FILE"));
+}
+
 #[macro_use]
 extern crate async_trait;
 #[macro_use]
diff --git a/librad/src/net/peer/storage.rs b/librad/src/net/peer/storage.rs
index dab06174c..03275742a 100644
--- a/librad/src/net/peer/storage.rs
+++ b/librad/src/net/peer/storage.rs
@@ -174,6 +174,25 @@ pub fn urn_context(local_peer_id: PeerId, urn: Either<Urn, Originates<Urn>>) ->
     }
 }
 
+#[cfg(feature = "usdt")]
+fn report_have(peer: &PeerId, urn: &Urn) {
+    let p: &str = &peer.default_encoding();
+    let u: &str = &urn.encode_id();
+    crate::usdt::radicle_link::have_recv(p.as_ptr() as *mut _, u.as_ptr() as *mut _);
+}
+
+#[cfg(not(feature = "usdt"))]
+fn report_have(peer: &PeerId, urn: &Urn) { }
+
+#[cfg(feature = "usdt")]
+fn report_want(peer: &Option<PeerId>, urn: &Urn) {
+    let p: &str = &peer.map_or_else(|| "unknown".to_owned(), |o| o.default_encoding());
+    let u: &str = &urn.encode_id();
+    crate::usdt::radicle_link::want_recv(p.as_ptr() as *mut _, u.as_ptr() as *mut _);
+}
+#[cfg(not(feature = "usdt"))]
+fn report_want(peer: &Option<PeerId>, urn: &Urn) { }
+
 #[async_trait]
 impl broadcast::LocalStorage<SocketAddr> for Storage {
     type Update = gossip::Payload;
@@ -187,6 +206,8 @@ impl broadcast::LocalStorage<SocketAddr> for Storage {
 
         let (provider, addr_hints) = provider.into();
 
+        report_have(&provider, &has.urn);
+
         // If the `has` doesn't tell us to look into a specific remote-tracking
         // branch, assume we want the `provider`'s.
         let origin = has.origin.unwrap_or(provider);
@@ -258,6 +279,8 @@ impl broadcast::LocalStorage<SocketAddr> for Storage {
 
     #[tracing::instrument(level = "debug", skip(self))]
     async fn ask(&self, want: Self::Update) -> bool {
+        report_want(&want.origin, &want.urn);
+
         self.git_has(
             match want.origin {
                 Some(origin) => Right(Originates {