Johnathan Corgan 70e365b14d Fix PMTUD: per-destination path MTU check and ICMPv6 MTU field width ...

Two bugs prevented Path MTU Discovery from working across heterogeneous
links (e.g., ethernet→UDP boundary):

1. ICMPv6 Packet Too Big wrote the MTU as u16 into a 32-bit field
   (RFC 4443 §3.2), causing the kernel to read an inflated value.
   Fixed by changing build_packet_too_big() to use u32 and writing
   all 4 bytes.

2. handle_tun_outbound() only checked the local transport MTU, not
   the per-destination PathMtuState updated by MtuExceeded signals.
   Added a PathMtuState check after session lookup so subsequent
   oversized packets generate ICMPv6 PTB on TUN instead of being
   forwarded and dropped at the bottleneck hop.

Added integration test exercising the full PMTUD loop across a 3-node
chain with heterogeneous MTUs: oversized packet → forwarding failure →
MtuExceeded signal → PathMtuState update → ICMPv6 PTB on TUN.

2026-03-04 03:34:41 +00:00

..

config.rs

Improve README and enable DNS resolver by default

2026-02-24 18:58:32 +00:00

dns.rs

Module reorganization, identity test coverage, design doc corrections

2026-02-15 17:11:58 +00:00

icmp_rate_limit.rs

feat: implement ICMP Packet Too Big and TCP MSS clamping for MTU handling

2026-02-16 21:33:21 +00:00

icmp.rs

Fix PMTUD: per-destination path MTU check and ICMPv6 MTU field width

2026-03-04 03:34:41 +00:00

mod.rs

feat: implement ICMP Packet Too Big and TCP MSS clamping for MTU handling

2026-02-16 21:33:21 +00:00

tcp_mss.rs

feat: implement ICMP Packet Too Big and TCP MSS clamping for MTU handling

2026-02-16 21:33:21 +00:00

tun.rs

Update dependencies: rand 0.10, rtnetlink 0.20, tun 0.8, and others

2026-02-24 18:02:06 +00:00