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use ip::IpNextHeaderProtocol;
use pnet_macros_support::types::u16be;
use std::convert::TryInto;
use std::net::{Ipv4Addr, Ipv6Addr};
use std::u16;
use std::u8;
pub trait Octets {
type Output;
fn octets(&self) -> Self::Output;
}
impl Octets for u64 {
type Output = [u8; 8];
fn octets(&self) -> Self::Output {
[
(*self >> 56) as u8,
(*self >> 48) as u8,
(*self >> 40) as u8,
(*self >> 32) as u8,
(*self >> 24) as u8,
(*self >> 16) as u8,
(*self >> 8) as u8,
*self as u8,
]
}
}
impl Octets for u32 {
type Output = [u8; 4];
fn octets(&self) -> Self::Output {
[
(*self >> 24) as u8,
(*self >> 16) as u8,
(*self >> 8) as u8,
*self as u8,
]
}
}
impl Octets for u16 {
type Output = [u8; 2];
fn octets(&self) -> Self::Output {
[(*self >> 8) as u8, *self as u8]
}
}
impl Octets for u8 {
type Output = [u8; 1];
fn octets(&self) -> Self::Output {
[*self]
}
}
pub fn checksum(data: &[u8], skipword: usize) -> u16be {
if data.len() == 0 {
return 0;
}
let sum = sum_be_words(data, skipword);
finalize_checksum(sum)
}
fn finalize_checksum(mut sum: u32) -> u16be {
while sum >> 16 != 0 {
sum = (sum >> 16) + (sum & 0xFFFF);
}
!sum as u16
}
pub fn ipv4_checksum(
data: &[u8],
skipword: usize,
extra_data: &[u8],
source: &Ipv4Addr,
destination: &Ipv4Addr,
next_level_protocol: IpNextHeaderProtocol,
) -> u16be {
let mut sum = 0u32;
sum += ipv4_word_sum(source);
sum += ipv4_word_sum(destination);
let IpNextHeaderProtocol(next_level_protocol) = next_level_protocol;
sum += next_level_protocol as u32;
let len = data.len() + extra_data.len();
sum += len as u32;
sum += sum_be_words(data, skipword);
sum += sum_be_words(extra_data, extra_data.len() / 2);
finalize_checksum(sum)
}
fn ipv4_word_sum(ip: &Ipv4Addr) -> u32 {
let octets = ip.octets();
((octets[0] as u32) << 8 | octets[1] as u32) + ((octets[2] as u32) << 8 | octets[3] as u32)
}
pub fn ipv6_checksum(
data: &[u8],
skipword: usize,
extra_data: &[u8],
source: &Ipv6Addr,
destination: &Ipv6Addr,
next_level_protocol: IpNextHeaderProtocol,
) -> u16be {
let mut sum = 0u32;
sum += ipv6_word_sum(source);
sum += ipv6_word_sum(destination);
let IpNextHeaderProtocol(next_level_protocol) = next_level_protocol;
sum += next_level_protocol as u32;
let len = data.len() + extra_data.len();
sum += len as u32;
sum += sum_be_words(data, skipword);
sum += sum_be_words(extra_data, extra_data.len() / 2);
finalize_checksum(sum)
}
fn ipv6_word_sum(ip: &Ipv6Addr) -> u32 {
ip.segments().iter().map(|x| *x as u32).sum()
}
fn sum_be_words(data: &[u8], skipword: usize) -> u32 {
if data.len() == 0 {
return 0;
}
let len = data.len();
let mut cur_data = &data[..];
let mut sum = 0u32;
let mut i = 0;
while cur_data.len() >= 2 {
if i != skipword {
sum += u16::from_be_bytes(cur_data[0..2].try_into().unwrap()) as u32;
}
cur_data = &cur_data[2..];
i += 1;
}
if i != skipword && len & 1 != 0 {
sum += (data[len - 1] as u32) << 8;
}
sum
}
#[cfg(test)]
mod tests {
use super::sum_be_words;
use std::slice;
#[test]
fn sum_be_words_different_skipwords() {
let data = (0..11).collect::<Vec<u8>>();
assert_eq!(7190, sum_be_words(&data, 1));
assert_eq!(6676, sum_be_words(&data, 2));
assert_eq!(7705, sum_be_words(&data, 99));
assert_eq!(7705, sum_be_words(&data, 101));
}
#[test]
fn sum_be_words_small_sizes() {
let data_zero = vec![0; 0];
assert_eq!(0, sum_be_words(&data_zero, 0));
assert_eq!(0, sum_be_words(&data_zero, 10));
let data_one = vec![1; 1];
assert_eq!(0, sum_be_words(&data_zero, 0));
assert_eq!(256, sum_be_words(&data_one, 1));
let data_two = vec![1; 2];
assert_eq!(0, sum_be_words(&data_two, 0));
assert_eq!(257, sum_be_words(&data_two, 1));
let data_three = vec![4; 3];
assert_eq!(1024, sum_be_words(&data_three, 0));
assert_eq!(1028, sum_be_words(&data_three, 1));
assert_eq!(2052, sum_be_words(&data_three, 2));
assert_eq!(2052, sum_be_words(&data_three, 3));
}
#[test]
fn sum_be_words_misaligned_ptr() {
let mut data = vec![0; 13];
let ptr = match data.as_ptr() as usize % 2 {
0 => unsafe { data.as_mut_ptr().offset(1) },
_ => data.as_mut_ptr(),
};
unsafe {
let slice_data = slice::from_raw_parts_mut(ptr, 12);
for i in 0..11 {
slice_data[i] = i as u8;
}
assert_eq!(7190, sum_be_words(&slice_data, 1));
assert_eq!(6676, sum_be_words(&slice_data, 2));
assert_eq!(7705, sum_be_words(&slice_data, 99));
assert_eq!(7705, sum_be_words(&slice_data, 101));
}
}
}
#[cfg(all(test, feature = "benchmark"))]
mod checksum_benchmarks {
use super::checksum;
use test::{black_box, Bencher};
#[bench]
fn bench_checksum_small(b: &mut Bencher) {
let data = vec![99u8; 20];
b.iter(|| checksum(black_box(&data), 5));
}
#[bench]
fn bench_checksum_large(b: &mut Bencher) {
let data = vec![123u8; 1024];
b.iter(|| checksum(black_box(&data), 5));
}
}