From 55d8bcf3860d2cf5db7f59b8b5caaa32de6e668d Mon Sep 17 00:00:00 2001
From: Alessandro Decina <alessandro.d@gmail.com>
Date: Sun, 14 Feb 2021 06:11:20 +0000
Subject: [PATCH] xdp: add support for attaching with custom xdp flags

---
 aya/Cargo.toml          |  1 +
 aya/src/lib.rs          |  2 ++
 aya/src/programs/mod.rs | 16 ++++++++--------
 aya/src/programs/xdp.rs | 21 ++++++++++++++++++---
 4 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/aya/Cargo.toml b/aya/Cargo.toml
index 46df8cd0..28471b14 100644
--- a/aya/Cargo.toml
+++ b/aya/Cargo.toml
@@ -8,6 +8,7 @@ edition = "2018"
 libc = { version = "0.2" }
 thiserror = "1"
 object = { version = "0.23", default-features = false, features = ["std", "read_core", "elf"] }
+bitflags = "1.2.1"
 bytes = "1"
 lazy_static = "1"
 parking_lot = { version = "0.11.1", features = ["send_guard"] }
diff --git a/aya/src/lib.rs b/aya/src/lib.rs
index af8b572c..fe7dc5d4 100644
--- a/aya/src/lib.rs
+++ b/aya/src/lib.rs
@@ -2,6 +2,8 @@
 
 #[macro_use]
 extern crate lazy_static;
+#[macro_use]
+extern crate bitflags;
 
 mod bpf;
 mod generated;
diff --git a/aya/src/programs/mod.rs b/aya/src/programs/mod.rs
index b78eebfb..60f81c12 100644
--- a/aya/src/programs/mod.rs
+++ b/aya/src/programs/mod.rs
@@ -1,18 +1,18 @@
 mod perf_attach;
-mod probe;
-mod socket_filter;
-mod trace_point;
-mod xdp;
+pub mod probe;
+pub mod socket_filter;
+pub mod trace_point;
+pub mod xdp;
 
 use libc::{close, ENOSPC};
 use std::{cell::RefCell, cmp, convert::TryFrom, ffi::CStr, io, os::raw::c_uint, rc::Rc};
 use thiserror::Error;
 
 use perf_attach::*;
-pub use probe::*;
-pub use socket_filter::*;
-pub use trace_point::*;
-pub use xdp::*;
+pub use probe::{KProbe, KProbeError, UProbe, UProbeError};
+pub use socket_filter::{SocketFilter, SocketFilterError};
+pub use trace_point::{TracePoint, TracePointError};
+pub use xdp::{Xdp, XdpError};
 
 use crate::{obj, sys::bpf_load_program, RawFd};
 #[derive(Debug, Error)]
diff --git a/aya/src/programs/xdp.rs b/aya/src/programs/xdp.rs
index 97bfc7eb..d36ea65f 100644
--- a/aya/src/programs/xdp.rs
+++ b/aya/src/programs/xdp.rs
@@ -1,9 +1,13 @@
+use bitflags;
 use libc::if_nametoindex;
 use std::{ffi::CString, io};
 use thiserror::Error;
 
 use crate::{
-    generated::{bpf_attach_type::BPF_XDP, bpf_prog_type::BPF_PROG_TYPE_XDP, XDP_FLAGS_REPLACE},
+    generated::{
+        bpf_attach_type::BPF_XDP, bpf_prog_type::BPF_PROG_TYPE_XDP, XDP_FLAGS_DRV_MODE,
+        XDP_FLAGS_HW_MODE, XDP_FLAGS_REPLACE, XDP_FLAGS_SKB_MODE, XDP_FLAGS_UPDATE_IF_NOEXIST,
+    },
     programs::{load_program, FdLink, Link, LinkRef, ProgramData, ProgramError},
     sys::bpf_link_create,
     sys::kernel_version,
@@ -20,6 +24,17 @@ pub enum XdpError {
     },
 }
 
+bitflags! {
+    #[derive(Default)]
+    pub struct XdpFlags: u32 {
+        const SKB_MODE = XDP_FLAGS_SKB_MODE;
+        const DRV_MODE = XDP_FLAGS_DRV_MODE;
+        const HW_MODE = XDP_FLAGS_HW_MODE;
+        const REPLACE = XDP_FLAGS_REPLACE;
+        const UPDATE_IF_NOEXIST = XDP_FLAGS_UPDATE_IF_NOEXIST;
+    }
+}
+
 #[derive(Debug)]
 pub struct Xdp {
     pub(crate) data: ProgramData,
@@ -34,7 +49,7 @@ impl Xdp {
         self.data.name.to_string()
     }
 
-    pub fn attach(&mut self, interface: &str) -> Result<LinkRef, ProgramError> {
+    pub fn attach(&mut self, interface: &str, flags: XdpFlags) -> Result<LinkRef, ProgramError> {
         let prog_fd = self.data.fd_or_err()?;
 
         let c_interface = CString::new(interface).unwrap();
@@ -47,7 +62,7 @@ impl Xdp {
 
         let k_ver = kernel_version().unwrap();
         if k_ver >= (5, 7, 0) {
-            let link_fd = bpf_link_create(prog_fd, if_index + 42, BPF_XDP, 0)
+            let link_fd = bpf_link_create(prog_fd, if_index, BPF_XDP, flags.bits)
                 .map_err(|(_, io_error)| ProgramError::BpfLinkCreateError { io_error })?
                 as RawFd;
             Ok(self