Unconnected raw ICMP sockets receive every ICMP packet arriving at the
host, so any ICMP traffic refreshed the read deadline of every flow and
stale flows (with their raw sockets and goroutines) accumulated forever,
making per-ping cost grow linearly with uptime.
Expire flows based on their own activity only, and on Linux attach a
classic BPF ident filter to each raw socket so other flows' packets are
dropped in the kernel instead of waking every flow.
Unconnected raw ICMP sockets receive every ICMP packet arriving at the
host, so any ICMP traffic refreshed the read deadline of every flow and
stale flows (with their raw sockets and goroutines) were only reclaimed
by LRU eviction while processing all host ICMP traffic in the meantime.
Expire flows based on their own activity only, and on Linux attach a
classic BPF ident filter to each raw socket so other flows' packets are
dropped in the kernel instead of waking every flow.
When To() is 255.255.255.255 / ffff:...:ffff, Next() is invalid. Using
From() as the end key duplicated the start element and caused EEXIST.
Omit the end element so the half-open interval covers through max.
FixesSagerNet/sing-box#4316
The acceptLoop was rewriting any TCP destination within the TUN
address prefix to 127.0.0.1/::1. This incorrectly caught the
gateway address and other subnet addresses, not just the interface
address itself.
