CRITICAL BUGS FIXED:
1. STP build_bpdu runtime panic (link/stp.rs:121-123)
- Duration::total_millis() returns i64, to_be_bytes() = [u8; 8]
- But destination buffers (buf[29..31], buf[31..33], buf[33..35]) are 2 bytes
- copy_from_slice panics on length mismatch
- Triggered by every root bridge hello BPDU — daemon crash
- Fix: convert to ticks (1s = 256 ticks per IEEE 802.1D) as u16
2. SLAAC PIO off-by-2 byte parsing (slaac.rs:155-180)
- parse_router_advertisement used opt_data[2] for prefix length
- After pos += 2 consumed type+length, opt_data[0] is the prefix length
- All PIO fields were off by 2 — SLAAC got wrong prefix length, flags,
valid_lifetime (read Preferred Lifetime), preferred_lifetime (read Reserved2)
- Fix: use opt_data[0] for prefix length, [1] for flags, [2..6] for valid,
[6..10] for preferred, [14..30] for prefix bytes
3. ICMPv4 error wrong IHL extraction (icmp_error.rs:25, 62)
- (ipv4.version() & 0x0f) * 4 always computed 16
- smoltcp's version() returns 4 (version), not combined byte
- Fix: use ipv4.header_len()
4. UDP can_recv panic on port-only endpoint (scheme/udp.rs:54)
- data.addr.unwrap() panics if addr is None (e.g. udp/:53)
- is_specified() returns true when port is non-zero, even if addr is None
- Fix: use let-else pattern, accept all packets if addr is None
5. TCP .expect() calls crash daemon (scheme/tcp.rs)
- 5 .expect() calls in connect/listen/send/recv paths
- Any socket error panics the entire netstack daemon
- Fix: replace with .map_err() returning EIO
6. ICMP .unwrap() on malformed packets (scheme/icmp.rs:217-220)
- recv().expect() panics, Icmpv4Repr::parse().unwrap() panics
- Crafted/malformed ICMP packets would crash the daemon
- Fix: use match, drop unparseable packets
NEW TESTS (6 added, 29 total now passing):
- icmp_error::icmpv4_short_packet_returns_none
- icmp_error::icmpv4_preserves_destination_address (regression for bug 3)
- icmp_error::icmpv4_with_ip_options_includes_extended_header
- slaac::ra_with_pio_64_parses_correctly (regression for bug 2)
- link::stp::bpdu_minimal_parses
- link::stp::bpdu_short_returns_none
- link::stp::bpdu_wrong_protocol_returns_none
- link::stp::build_bpdu_does_not_panic (regression for bug 1)
The SLAAC test would have failed before the off-by-2 fix.
The STP build_bpdu test would have panicked before the ticks fix.
The ICMP tests verify the full IP header (incl. IHL=6 options) is preserved.
Red Bear OS
efa24228e3