fix: validate ICMP ID per socket, fix dual-stack ID mismatch

src/pinger.rs

@@ -56,8 +56,9 @@ pub fn run(args: Args, hosts_in: Vec<(String, IpAddr)>) {
   let fd4 = owned_fd4.as_ref().map(|o| o.as_raw_fd());
   let fd6 = owned_fd6.as_ref().map(|o| o.as_raw_fd());
 
-  let pid_id = (std::process::id() & 0xFFFF) as u16;
-  let my_id = dgram_id4.or(dgram_id6).unwrap_or(pid_id);
+  let pid_id  = (std::process::id() & 0xFFFF) as u16;
+  let my_id4  = dgram_id4.unwrap_or(pid_id);
+  let my_id6  = dgram_id6.unwrap_or(pid_id);
 
   let interval = Duration::from_millis(args.interval);
   let period   = Duration::from_millis(args.period);
@@ -103,7 +104,8 @@ pub fn run(args: Args, hosts_in: Vec<(String, IpAddr)>) {
 
       let is_ipv6  = hosts[idx].is_ipv6;
       let kind = if is_ipv6 { kind6 } else { kind4 };
-      let pkt = build_icmp_packet(my_id, seq, args.size, is_ipv6, kind);
+      let pkt_id = if is_ipv6 { my_id6 } else { my_id4 };
+      let pkt = build_icmp_packet(pkt_id, seq, args.size, is_ipv6, kind);
 
       let sent = match hosts[idx].addr {
         IpAddr::V4(ref a) => fd4.map(|fd| send_ping_v4(fd, a, &pkt)).unwrap_or(false),
@@ -136,16 +138,14 @@ pub fn run(args: Args, hosts_in: Vec<(String, IpAddr)>) {
       }
     }
 
-    for (fd_opt, is_v6, kind) in &[(fd4, false, kind4), (fd6, true, kind6)] {
+    for (fd_opt, is_v6, kind, expected_id) in &[(fd4, false, kind4, my_id4), (fd6, true,  kind6, my_id6),] {
       let fd = match fd_opt { Some(f) => *f, None => continue };
       loop {
-        let received = match recv_ping(fd, &mut recv_buf, *is_v6, *kind) {
+        let received = match recv_ping(fd, &mut recv_buf, *is_v6, *kind, Some(*expected_id)) {
           Some(r) => r,
           None => break,
         };
 
-        if received.id != my_id { continue; }
-
         if let Some(pending) = seqmap.get(&received.seq) {
           if Instant::now().duration_since(pending.sent_at) > timeout {
             seqmap.remove(&received.seq);

src/socket.rs

@@ -166,12 +166,11 @@ pub fn send_ping_v6(fd: RawFd, addr: &Ipv6Addr, pkt: &[u8]) -> bool {
 }
 
 pub struct ReceivedPing {
-  pub id: u16,
   pub seq: u16,
   pub raw_len: usize,
 }
 
-pub fn recv_ping(fd: RawFd, buf: &mut [u8], is_ipv6: bool, kind: SocketKind) -> Option<ReceivedPing> {
+pub fn recv_ping(fd: RawFd, buf: &mut [u8], is_ipv6: bool, kind: SocketKind, expected_id: Option<u16>) -> Option<ReceivedPing> {
   let mut src: libc::sockaddr_storage = unsafe { std::mem::zeroed() };
   let mut src_len = std::mem::size_of::<libc::sockaddr_storage>() as socklen_t;
 
@@ -211,8 +210,11 @@ pub fn recv_ping(fd: RawFd, buf: &mut [u8], is_ipv6: bool, kind: SocketKind) ->
 
   let id = u16::from_be_bytes([icmp[4], icmp[5]]);
 
+  if let Some(eid) = expected_id {
+    if id != eid { return None; }
+  }
+
   Some(ReceivedPing {
-    id,
     seq: u16::from_be_bytes([icmp[6], icmp[7]]),
     raw_len,
   })