net: update document on limitation of iprawsock on Windows

Fixed: golang#23209

Change-Id: I3bfe9f5192cbacf387386efda72f04eeec5ff3be
GitHub-Last-Rev: 660a62d
GitHub-Pull-Request: golang#74857
Reviewed-on: https://go-review.googlesource.com/c/go/+/692895
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Sean Liao <[email protected]>
Reviewed-by: Cherry Mui <[email protected]>
Reviewed-by: Damien Neil <[email protected]>
Auto-Submit: Sean Liao <[email protected]>

Author: aisk

src/net/iprawsock.go

@@ -25,6 +25,12 @@ import (
 // BUG(mikio): On JS and Plan 9, methods and functions related
 // to IPConn are not implemented.
 
+// BUG: On Windows, raw IP sockets are restricted by the operating system.
+// Sending TCP data, sending UDP data with invalid source addresses,
+// and calling bind with TCP protocol don't work.
+//
+// See Winsock reference for details.
+
 func ipAddrFromAddr(addr netip.Addr) *IPAddr {
 	return &IPAddr{
 		IP:   addr.AsSlice(),