mirror of
https://github.com/zaphar/icmp-socket.git
synced 2025-07-21 19:29:47 -04:00
Fix bug in packet parsing and ip_to_socket
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parent
89f866f4c0
commit
07d8ee676a
107
src/packet.rs
107
src/packet.rs
@ -25,20 +25,21 @@ fn sum_big_endian_words(bs: &[u8]) -> u32 {
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let len = bs.len();
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let mut data = &bs[..];
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let mut sum = 032;
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// We need to stop when we have less than 2 bytes left.
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let mut sum = 0u32;
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// Iterate by word which is two bytes.
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while data.len() >= 2 {
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sum += BigEndian::read_u16(&data[0..2]) as u32;
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// remove the first two now that we've already summed them
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// remove the first two bytes now that we've already summed them
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data = &data[2..];
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}
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if len % 2 != 0 { // If odd then checksum the last byte
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sum += (bs[len - 1] as u32) << 8;
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if (len % 2) != 0 { // If odd then checksum the last byte
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sum += (data[0] as u32) << 8;
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}
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return sum;
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}
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#[derive(Debug)]
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pub enum Icmpv6Message {
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// NOTE(JWALL): All of the below integers should be parsed as big endian on the
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// wire.
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@ -112,6 +113,7 @@ impl Icmpv6Message {
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}
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}
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#[derive(Debug)]
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pub struct Icmpv6Packet {
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// NOTE(JWALL): All of the below integers should be parsed as big endian on the
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// wire.
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@ -135,8 +137,8 @@ impl Icmpv6Packet {
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if bytes.len() < 8 {
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return Err(PacketParseError::PacketTooSmall(bytes.len()));
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}
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let (typ, code, checksum) = (bytes[0], bytes[1], BigEndian::read_u16(&bytes[2..3]));
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let next_field = BigEndian::read_u32(&bytes[4..7]);
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let (typ, code, checksum) = (bytes[0], bytes[1], BigEndian::read_u16(&bytes[2..4]));
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let next_field = BigEndian::read_u32(&bytes[4..8]);
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let payload = bytes[8..].to_owned();
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let message = match typ {
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1 => Unreachable{
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@ -160,13 +162,13 @@ impl Icmpv6Packet {
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payload: payload,
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},
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128 => EchoRequest{
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identifier: BigEndian::read_u16(&bytes[4..5]),
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sequence: BigEndian::read_u16(&bytes[6..7]),
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identifier: BigEndian::read_u16(&bytes[4..6]),
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sequence: BigEndian::read_u16(&bytes[6..8]),
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payload: payload,
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},
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129 => EchoReply{
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identifier: BigEndian::read_u16(&bytes[4..5]),
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sequence: BigEndian::read_u16(&bytes[6..7]),
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identifier: BigEndian::read_u16(&bytes[4..6]),
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sequence: BigEndian::read_u16(&bytes[6..8]),
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payload: payload,
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},
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_ => return Err(PacketParseError::UnrecognizedICMPType),
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@ -205,13 +207,13 @@ impl Icmpv6Packet {
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sum += ipv6_sum_words(dest);
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// according to rfc4443: https://tools.ietf.org/html/rfc4443#section-2.3
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// the ip next header value is 58
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sum += 58u32;
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sum += 58;
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// Then sum the len of the message bytes and then the message bytes starting
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// with the message type field and with the checksum field set to 0.
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let bytes = self.get_bytes(false);
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let len = bytes.len();
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sum += len as u32;
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// Then append the message bytes as a byte buffer starting with the message
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// type field with the checksum field set to 0.
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sum += sum_big_endian_words(&bytes);
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// handle the carry
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@ -342,3 +344,80 @@ impl From<Icmpv6PacketBuildError> for std::io::Error {
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std::io::Error::new(std::io::ErrorKind::Other, format!("{}", err))
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}
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}
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#[cfg(test)]
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mod checksum_tests {
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use super::*;
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#[test]
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fn echo_packet_parse_test() {
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// NOTE(jwall): I am shamelessly ripping ff the cases for this from libpnet
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// The equivalent of your typical ping -6 ::1%lo
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let lo = &Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1);
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let mut data = vec![
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0x80, // Icmpv6 Type
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0x00, // Code
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0xff, 0xff, // Checksum
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0x00, 0x00, // Id
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0x00, 0x01, // Sequence
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// 56 bytes of "random" data
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0x20, 0x20, 0x75, 0x73, 0x74, 0x20, 0x61, 0x20,
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0x66, 0x6c, 0x65, 0x73, 0x68, 0x20, 0x77, 0x6f,
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0x75, 0x6e, 0x64, 0x20, 0x20, 0x74, 0x69, 0x73,
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0x20, 0x62, 0x75, 0x74, 0x20, 0x61, 0x20, 0x73,
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0x63, 0x72, 0x61, 0x74, 0x63, 0x68, 0x20, 0x20,
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0x6b, 0x6e, 0x69, 0x67, 0x68, 0x74, 0x73, 0x20,
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0x6f, 0x66, 0x20, 0x6e, 0x69, 0x20, 0x20, 0x20
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];
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let pkt = Icmpv6Packet::parse(&data).unwrap();
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assert_eq!(pkt.typ, 128);
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assert_eq!(pkt.code, 0x00);
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if let EchoRequest{
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identifier,
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sequence,
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payload,
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}= &pkt.message {
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assert_eq!(*identifier, 0);
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assert_eq!(*sequence, 1);
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assert_eq!(payload, &[
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0x20, 0x20, 0x75, 0x73, 0x74, 0x20, 0x61, 0x20,
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0x66, 0x6c, 0x65, 0x73, 0x68, 0x20, 0x77, 0x6f,
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0x75, 0x6e, 0x64, 0x20, 0x20, 0x74, 0x69, 0x73,
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0x20, 0x62, 0x75, 0x74, 0x20, 0x61, 0x20, 0x73,
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0x63, 0x72, 0x61, 0x74, 0x63, 0x68, 0x20, 0x20,
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0x6b, 0x6e, 0x69, 0x67, 0x68, 0x74, 0x73, 0x20,
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0x6f, 0x66, 0x20, 0x6e, 0x69, 0x20, 0x20, 0x20
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]);
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} else {
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assert!(false, "Packet did not parse as an EchoRequest {:?}", pkt.message);
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}
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assert_eq!(pkt.get_bytes(true), data);
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assert_eq!(pkt.calculate_checksum(lo, lo), 0x1d2e);
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// Check echo response as well
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data[0] = 0x81;
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let pkt = Icmpv6Packet::parse(&data).unwrap();
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assert_eq!(pkt.typ, 129);
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assert_eq!(pkt.code, 0);
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if let EchoReply{
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identifier,
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sequence,
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payload,
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}= &pkt.message {
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assert_eq!(*identifier, 0);
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assert_eq!(*sequence, 1);
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assert_eq!(payload, &[
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0x20, 0x20, 0x75, 0x73, 0x74, 0x20, 0x61, 0x20,
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0x66, 0x6c, 0x65, 0x73, 0x68, 0x20, 0x77, 0x6f,
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0x75, 0x6e, 0x64, 0x20, 0x20, 0x74, 0x69, 0x73,
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0x20, 0x62, 0x75, 0x74, 0x20, 0x61, 0x20, 0x73,
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0x63, 0x72, 0x61, 0x74, 0x63, 0x68, 0x20, 0x20,
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0x6b, 0x6e, 0x69, 0x67, 0x68, 0x74, 0x73, 0x20,
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0x6f, 0x66, 0x20, 0x6e, 0x69, 0x20, 0x20, 0x20
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]);
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} else {
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assert!(false, "Packet did not parse as an EchoReply {:?}", pkt.message);
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}
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assert_eq!(pkt.calculate_checksum(lo, lo), 0x1c2e);
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}
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}
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@ -20,7 +20,7 @@ use socket2::{Socket, Domain, Type, Protocol};
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use crate::packet::Icmpv6Packet;
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fn ip_to_socket(ip: &IpAddr) -> SocketAddr {
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format!("{}:0", ip).parse::<SocketAddr>().unwrap()
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SocketAddr::new(*ip, 0)
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}
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pub struct Opts {
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