Capture ENOBUFS message into Sentry only once (#19)

* Populate Sentry Release

* Reverted new line

* Update src/main.rs

Co-authored-by: Nikolay Edigaryev <edigaryev@gmail.com>

Co-authored-by: Nikolay Edigaryev <edigaryev@gmail.com>

.cirrus.yml

@@ -23,12 +23,11 @@ task:
     SENTRY_AUTH_TOKEN: ENCRYPTED[!c16a5cf7da5f856b4bc2f21fe8cb7aa2a6c981f851c094ed4d3025fd02ea59a58a86cee8b193a69a1fc20fa217e56ac3!]
   install_rust_script:
     - curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y
-  install_goreleaser_script:
-    - brew install go goreleaser/tap/goreleaser-pro
+  install_script:
+    - brew install go goreleaser/tap/goreleaser-pro getsentry/tools/sentry-cli
   build_script:
     - cargo build --profile release-with-debug
-  install_sentry_cli_script:
-    - brew install getsentry/tools/sentry-cli
+  release_script: goreleaser
   upload_sentry_debug_files_script:
     - cd target/release-with-debug/
     # Generate and upload symbols
@@ -37,4 +36,8 @@ task:
     # Bundle and upload sources
     - sentry-cli debug-files bundle-sources softnet.dSYM/
     - sentry-cli debug-files upload -o $SENTRY_ORG -p $SENTRY_PROJECT softnet.src.zip
-  release_script: goreleaser
+  create_sentry_release_script:
+    - export SENTRY_RELEASE="softnet@$CIRRUS_TAG"
+    - sentry-cli releases new $SENTRY_RELEASE
+    - sentry-cli releases set-commits $SENTRY_RELEASE --auto
+    - sentry-cli releases finalize $SENTRY_RELEASE

lib/poller.rs

@@ -52,8 +52,14 @@ impl Poller {
         self.poller
             .wait(&mut self.events, Some(Duration::from_millis(100)))?;
 
-        let vm_readable = self.events.iter().any(|ev| ev.key == EventKey::VM.into());
-        let host_readable = self.events.iter().any(|ev| ev.key == EventKey::Host.into());
+        let vm_readable = self
+            .events
+            .iter()
+            .any(|ev| ev.key == Into::<usize>::into(EventKey::VM));
+        let host_readable = self
+            .events
+            .iter()
+            .any(|ev| ev.key == Into::<usize>::into(EventKey::Host));
 
         Ok((vm_readable, host_readable))
     }

lib/proxy/host.rs

@@ -16,10 +16,24 @@ impl Proxy {
             self.snoop(frame);
         }
 
-        self.vm
-            .write(frame.as_ref())
-            .map(|_| ())
-            .context("failed to write to the VM")
+        match self.vm.write(frame.as_ref()) {
+            Ok(_) => Ok(()),
+            Err(err) => {
+                if let Some(libc::ENOBUFS) = err.raw_os_error() {
+                    if !self.enobufs_encountered {
+                        sentry::capture_message(
+                            "No buffer space available in VM's socket",
+                            sentry::Level::Warning,
+                        );
+                        self.enobufs_encountered = true;
+                    }
+
+                    return Ok(());
+                }
+
+                Err(err).context("failed to write to the VM")
+            }
+        }
     }
 
     fn allowed_from_host(&mut self, frame: &EthernetFrame<&[u8]>) -> Option<()> {

lib/proxy/mod.rs

@@ -18,6 +18,7 @@ pub struct Proxy {
     poller: Poller,
     vm_mac_address: smoltcp::wire::EthernetAddress,
     dhcp_snooper: DhcpSnooper,
+    enobufs_encountered: bool,
 }
 
 impl Proxy {
@@ -32,6 +33,7 @@ impl Proxy {
             poller,
             vm_mac_address: smoltcp::wire::EthernetAddress(vm_mac_address.bytes()),
             dhcp_snooper: Default::default(),
+            enobufs_encountered: false,
         })
     }
 

rust-toolchain

@@ -0,0 +1 @@
+nightly

src/main.rs

@@ -2,6 +2,7 @@ use anyhow::{anyhow, Context};
 use clap::Parser;
 use privdrop::PrivDrop;
 use softnet::proxy::Proxy;
+use std::borrow::Cow;
 use std::env;
 use std::os::raw::c_int;
 use std::os::unix::io::RawFd;
@@ -54,13 +55,14 @@ fn main() -> ExitCode {
 
     // Initialize Sentry
     let _sentry = sentry::init(sentry::ClientOptions {
+        release: option_env!("CIRRUS_TAG").map(|tag| { Cow::from(format!("softnet@{tag}")) }),
         ..Default::default()
     });
 
     // Enrich future events with Cirrus CI-specific tags
     if let Ok(tags) = env::var("CIRRUS_SENTRY_TAGS") {
         sentry::configure_scope(|scope| {
-            for (key, value) in tags.split(",").map(|tag| tag.split_once("=")).flatten() {
+            for (key, value) in tags.split(',').filter_map(|tag| tag.split_once('=')) {
                 scope.set_tag(key, value);
             }
         });