Hygiene: scripts, CI, docs and manifests

- scripts/in-namespace.sh set CARGO_TARGET_DIR to the empty string when
  it was unset, which cargo refuses, and dropped RUSTFLAGS, so the run
  in the namespace rebuilt what kernel-tests.sh had just built. Each is
  passed on only where set.
- The README's list of unsupported features still had route reflection
  and graceful restart, both of which exist; the command-line reference
  lacked SIGUSR1 and exit status 75; the HTTP API reference did not say
  what errors look like.
- The event stream said "missed 0 events" for the best-routes stream,
  which does not count what it missed; it leaves the count out now.
- CI lints bgp-bench with its count-memory feature, which nothing built.
- bgp-bench had two unused dev-dependencies; bgp-integration-tests had
  three dependencies that only its tests and examples use.
- install.sh updates apt before installing; two-routers.sh loses an
  unused variable; small things in the web crate.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

crates/bench/Cargo.toml

@@ -21,8 +21,6 @@ bgp-integration-tests.workspace = true
 bgp-rib.workspace = true
 bgp-server.workspace = true
 tokio.workspace = true
-tracing.workspace = true
-tracing-subscriber.workspace = true
 
 [features]
 # Counts every allocation, to report how much memory a table holds. The

crates/bench/benches/full_table.rs

@@ -17,7 +17,7 @@ use std::sync::atomic::{AtomicUsize, Ordering};
 use std::time::{Duration, Instant};
 
 use bgp_bench::memory::{Region, describe};
-use bgp_bench::{Prefixes, Shape, announcements, encoded, wire_context};
+use bgp_bench::{Prefixes, Shape, announcements, encoded, env, wire_context};
 use bgp_integration_tests::test_peer::TestPeer;
 use bgp_integration_tests::test_server::TestServer;
 use bgp_packet::message::{Message, PathAttribute};
@@ -25,13 +25,6 @@ use bgp_primitives::ip_prefix::IpPrefix;
 use bgp_rib::table::{PeerIndex, PeerInfo, RibTable};
 use bytes::BytesMut;
 
-fn env(name: &str, default: usize) -> usize {
-    std::env::var(name)
-        .ok()
-        .and_then(|v| v.parse().ok())
-        .unwrap_or(default)
-}
-
 fn mib(bytes: usize) -> f64 {
     bytes as f64 / (1024.0 * 1024.0)
 }

crates/bench/benches/transit.rs

@@ -7,7 +7,7 @@ use std::net::Ipv4Addr;
 use std::sync::Arc;
 use std::time::{Duration, Instant};
 
-use bgp_bench::{Prefixes, Shape, announcements, encoded};
+use bgp_bench::{Prefixes, Shape, announcements, encoded, env};
 use bgp_integration_tests::test_peer::TestPeer;
 use bgp_integration_tests::test_server::TestServer;
 use bgp_packet::message::PathAttribute;
@@ -15,13 +15,6 @@ use bgp_server::marks::{Control, Marks};
 use bgp_server::policy::ExportPolicy;
 use bytes::BytesMut;
 
-fn env(name: &str, default: usize) -> usize {
-    std::env::var(name)
-        .ok()
-        .and_then(|v| v.parse().ok())
-        .unwrap_or(default)
-}
-
 /// How a server passes routes on in one run.
 #[derive(Clone, Copy)]
 enum Passing {

crates/bench/src/lib.rs

@@ -1,9 +1,10 @@
 //! A synthetic copy of the Internet routing table, as the UPDATE messages a
 //! peer would send to announce it.
 //!
-//! It is made up, not captured, so that the benchmarks need no data files
-//! and give the same input every run. It is shaped like the real thing where
-//! that matters for cost:
+//! It is made up, not captured, so that the benchmarks of a synthetic table
+//! need no data files and give the same input every run; the one of a real
+//! table reads an MRT dump instead, see [`mrt`]. It is shaped like the real
+//! thing where that matters for cost:
 //!
 //! - about a million IPv4 prefixes, most of them /24s, and about a quarter
 //!   of a million IPv6 prefixes, most of them /48s;
@@ -163,7 +164,7 @@ pub fn announcements(prefixes: &Prefixes, shape: Shape, peer: u32) -> Vec<Update
         let hops = 2 + rng.below(4) as usize;
         let mut path = vec![peer_asn];
         path.extend((0..hops).map(|_| 1 + rng.below(400_000) as u32));
-        let mut attributes = vec![
+        let attributes = vec![
             PathAttribute::Origin(OriginPathAttribute::IGP),
             PathAttribute::AsPath(AsPathAttribute {
                 segments: vec![AsPathSegment {
@@ -199,7 +200,7 @@ pub fn announcements(prefixes: &Prefixes, shape: Shape, peer: u32) -> Vec<Update
         } else {
             None
         };
-        (std::mem::take(&mut attributes), later, large)
+        (attributes, later, large)
     };
 
     let mut updates = Vec::new();
@@ -283,3 +284,12 @@ pub fn wire_context() -> ParserContext {
         add_path: Vec::new(),
     }
 }
+
+/// The value of the environment variable `name` as a number, or `default`
+/// when it is not set or is not one: how the benchmarks take their size.
+pub fn env(name: &str, default: usize) -> usize {
+    std::env::var(name)
+        .ok()
+        .and_then(|v| v.parse().ok())
+        .unwrap_or(default)
+}