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extern crate libc;
#[repr(C)]
pub struct bpf_insn {
code: libc::c_ushort,
jt: libc::c_uchar,
jf: libc::c_uchar,
k: libc::uint32_t,
}
#[allow(non_camel_case_types)]
type bpf_filter_func = extern "C" fn(*const libc::c_uchar, libc::c_uint, libc::c_uint) -> libc::c_uint;
extern "C" {
fn bpf_jit_compile(filter: *const bpf_insn, nins: libc::c_uint, size: *mut libc::size_t) -> Option<bpf_filter_func>;
}
pub struct BpfJitFilter {
func: bpf_filter_func,
size: usize,
}
impl BpfJitFilter {
pub fn compile(instructions: &[bpf_insn]) -> Option<BpfJitFilter> {
let mut size: libc::size_t = 0;
match unsafe { bpf_jit_compile(instructions.as_ptr(), instructions.len() as u32, &mut size) } {
Some(f) => Some(BpfJitFilter {
func: f,
size: size,
}),
None => None,
}
}
pub fn matched(&self, buf: &[u8]) -> bool {
(self.func)(buf.as_ptr(), buf.len() as u32, buf.len() as u32) > 0
}
}
impl Drop for BpfJitFilter {
fn drop(&mut self) {
use std::mem;
unsafe {
let ptr = mem::transmute(self.func);
libc::munmap(ptr, self.size);
}
}
}
impl Clone for BpfJitFilter {
fn clone(&self) -> Self {
use std::ptr;
use std::mem;
let code = unsafe {
let mem = libc::mmap(ptr::null_mut(), self.size, libc::PROT_READ | libc::PROT_WRITE,
libc::MAP_ANON | libc::MAP_PRIVATE, -1, 0);
ptr::copy_nonoverlapping(mem::transmute(self.func), mem, self.size);
libc::mprotect(mem, self.size, libc::PROT_READ | libc::PROT_EXEC);
mem
};
BpfJitFilter {
func: unsafe { mem::transmute(code) },
size: self.size,
}
}
}
#[test]
fn simple_match() {
let filter = [
bpf_insn { code: 0x28, jt: 0, jf: 0, k: 0x0000000c },
bpf_insn { code: 0x15, jt: 8, jf: 0, k: 0x000086dd },
bpf_insn { code: 0x15, jt: 0, jf: 7, k: 0x00000800 },
bpf_insn { code: 0x30, jt: 0, jf: 0, k: 0x00000017 },
bpf_insn { code: 0x15, jt: 0, jf: 5, k: 0x00000006 },
bpf_insn { code: 0x20, jt: 0, jf: 0, k: 0x0000001a },
bpf_insn { code: 0x15, jt: 2, jf: 0, k: 0xb9321902 },
bpf_insn { code: 0x20, jt: 0, jf: 0, k: 0x0000001e },
bpf_insn { code: 0x15, jt: 0, jf: 1, k: 0xb9321902 },
bpf_insn { code: 0x6, jt: 0, jf: 0, k: 0x0000ffff },
bpf_insn { code: 0x6, jt: 0, jf: 0, k: 0x00000000 },
];
let packet = [
0x68, 0x05, 0xca, 0x21, 0x58, 0x86,
0x94, 0xde, 0x80, 0x69, 0xbb, 0xe6,
0x08, 0x00, 0x45, 0x00,
0x00, 0x3c, 0x78, 0x85, 0x40, 0x00,
0x40, 0x06, 0x13, 0xb6, 0x0a, 0x64,
0xd1, 0xe8, 0xb9, 0x32,
0x19, 0x02, 0x83, 0xbf, 0x00, 0x16,
0x8d, 0x70, 0xa5, 0x97, 0x00, 0x00,
0x00, 0x00, 0xa0, 0x02,
0x72, 0x10, 0x74, 0x3e, 0x00, 0x00,
0x02, 0x04, 0x05, 0xb4, 0x04, 0x02,
0x08, 0x0a, 0x1f, 0x40,
0xdd, 0x12, 0x00, 0x00, 0x00, 0x00,
0x01, 0x03, 0x03, 0x07,
];
let jit_filter = BpfJitFilter::compile(&filter).unwrap();
assert!(jit_filter.matched(&packet) == true);
}
#[test]
fn simple_match_cloned() {
let filter = [
bpf_insn { code: 0x28, jt: 0, jf: 0, k: 0x0000000c },
bpf_insn { code: 0x15, jt: 8, jf: 0, k: 0x000086dd },
bpf_insn { code: 0x15, jt: 0, jf: 7, k: 0x00000800 },
bpf_insn { code: 0x30, jt: 0, jf: 0, k: 0x00000017 },
bpf_insn { code: 0x15, jt: 0, jf: 5, k: 0x00000006 },
bpf_insn { code: 0x20, jt: 0, jf: 0, k: 0x0000001a },
bpf_insn { code: 0x15, jt: 2, jf: 0, k: 0xb9321902 },
bpf_insn { code: 0x20, jt: 0, jf: 0, k: 0x0000001e },
bpf_insn { code: 0x15, jt: 0, jf: 1, k: 0xb9321902 },
bpf_insn { code: 0x6, jt: 0, jf: 0, k: 0x0000ffff },
bpf_insn { code: 0x6, jt: 0, jf: 0, k: 0x00000000 },
];
let packet = [
0x68, 0x05, 0xca, 0x21, 0x58, 0x86,
0x94, 0xde, 0x80, 0x69, 0xbb, 0xe6,
0x08, 0x00, 0x45, 0x00,
0x00, 0x3c, 0x78, 0x85, 0x40, 0x00,
0x40, 0x06, 0x13, 0xb6, 0x0a, 0x64,
0xd1, 0xe8, 0xb9, 0x32,
0x19, 0x02, 0x83, 0xbf, 0x00, 0x16,
0x8d, 0x70, 0xa5, 0x97, 0x00, 0x00,
0x00, 0x00, 0xa0, 0x02,
0x72, 0x10, 0x74, 0x3e, 0x00, 0x00,
0x02, 0x04, 0x05, 0xb4, 0x04, 0x02,
0x08, 0x0a, 0x1f, 0x40,
0xdd, 0x12, 0x00, 0x00, 0x00, 0x00,
0x01, 0x03, 0x03, 0x07,
];
let jit_filter = BpfJitFilter::compile(&filter).unwrap();
let cloned_filter = jit_filter.clone();
assert!(cloned_filter.matched(&packet) == true);
}