net_gen: replace net_gen with libc

The libc crate provides all functionality provided by the net_gen crate.
Removing the net_gen crate reduces the maintenance burden.

The switch to libc required some fixes, most notably the switch from a
`Vec<u8>` to a `CString` for the `net_util::Tap.if_name` field.

On-behalf-of: SAP julian.schindel@sap.com
Signed-off-by: Julian Schindel <julian.schindel@cyberus-technology.de>

fuzz/Cargo.lock

@@ -801,13 +801,6 @@ dependencies = [
  "zerocopy",
 ]
 
-[[package]]
-name = "net_gen"
-version = "0.1.0"
-dependencies = [
- "vmm-sys-util",
-]
-
 [[package]]
 name = "net_util"
 version = "0.1.0"
@@ -816,7 +809,6 @@ dependencies = [
  "getrandom 0.4.2",
  "libc",
  "log",
- "net_gen",
  "rate_limiter",
  "serde",
  "thiserror",
@@ -1235,7 +1227,6 @@ dependencies = [
  "anyhow",
  "libc",
  "log",
- "net_gen",
  "thiserror",
  "vmm-sys-util",
 ]

fuzz/fuzz_targets/net.rs

@@ -64,7 +64,7 @@ fuzz_target!(|bytes: &[u8]| -> Corpus {
     }
 
     let (dummy_tap_frontend, dummy_tap_backend) = create_socketpair().unwrap();
-    let if_name = "fuzzer_tap_name".as_bytes().to_vec();
+    let if_name = "fuzzer_tap_name";
     let tap = net_util::Tap::new_for_fuzzing(dummy_tap_frontend, if_name);
 
     let mut net = virtio_devices::Net::new_with_tap(