fix: prevent pkg_config from emitting Cargo linking instructions

Cargo.toml

@@ -20,13 +20,13 @@ strip = true
 default = ["aya", "pkg-config"]
 # Enable IPv6 NAPT
 ipv6 = []
-# Enable Aya BPF loader, requires Rust>=1.80.0
+# Enable Aya BPF loader
 aya = [
     # the dep:aya is also used for determine kernel version so it's already included
 ]
 # Enable libbpf BPF loader
 libbpf = ["dep:libbpf-rs", "dep:libbpf-sys"]
-# Enable libbpf skeleton-wrapped BPF loader, requires unpublish self_cell for now
+# Enable libbpf skeleton-wrapped BPF loader
 libbpf-skel = [
     "dep:libbpf-rs",
     "dep:libbpf-sys",
@@ -39,9 +39,7 @@ bindgen = ["libbpf-sys?/bindgen"]
 static = ["libbpf-sys?/static"]
 #
 # libbpf is vendrored and static in any case.
-# Note currently there is a bug in libbpf-sys that prevent static linking if
-# system libbpf is present, delete system libbpf or /path/to/pkgconfig/libbpf.pc
-# to work around it. See https://github.com/libbpf/libbpf-sys/issues/112
+#
 
 [dependencies]
 anyhow = "1.0.93"

build.rs

@@ -49,7 +49,10 @@ fn einat_obj_build() {
     // Specify environment variable LIBBPF_NO_PKG_CONFIG=1 to disable pkg-config lookup.
     // Or just disable the "pkg-config" feature.
     #[cfg(feature = "pkg-config")]
-    match pkg_config::probe_library("libbpf") {
+    match pkg_config::Config::new()
+        .cargo_metadata(false)
+        .probe("libbpf")
+    {
         Ok(libbpf) => {
             let includes = libbpf
                 .include_paths

src/instance/mod.rs

@@ -12,6 +12,7 @@ use anyhow::{anyhow, Result};
 use cfg_if::cfg_if;
 #[cfg(any(feature = "aya", feature = "libbpf", feature = "libbpf-skel"))]
 use enum_dispatch::enum_dispatch;
+use ipnet::IpNet;
 use tracing::{debug, info};
 
 use crate::skel::einat;
@@ -202,6 +203,7 @@ fn apply_inet_config<P: InetPrefix, T: EinatEbpf + EinatEbpfInet<P>>(
     Ok(())
 }
 
+// FIXME: matching network prefix instead of simple `==` comparison
 fn remove_binding_and_ct_entries<T: EinatEbpf>(skel: &mut T, external_addr: IpAddr) -> Result<()> {
     let addr_flag = if external_addr.is_ipv4() {
         BindingFlags::ADDR_IPV4