commit 3b69d09c80 corrected the
unreachable handling for net/udp/icmp but introduced an unaligned store.
This splits the uint32_t data field into a two element uint16_t data
field to avoid the unaligned store.
Reference RFC1122:
https://datatracker.ietf.org/doc/html/rfc1122
----------------------------------------------
4.1.3 SPECIFIC ISSUES
4.1.3.1 Ports
If a datagram arrives addressed to a UDP port for which
there is no pending LISTEN call, UDP SHOULD send an ICMP
Port Unreachable message.
Signed-off-by: chao.an <anchao@xiaomi.com>
