[ip6] no anycast as source address (#5632)

- Check source address of packets from users
- Determine anycast address by MLE API for accuracy
- Replace anycast address with a valid unicast address when sending
  with platform UDP in UDP layer
- Replace anycast address with a valid unicast address in IP layer

tests/scripts/expect/cli-anycast.exp

@@ -0,0 +1,56 @@
+#!/usr/bin/expect -f
+#
+#  Copyright (c) 2020, The OpenThread Authors.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions are met:
+#  1. Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#  2. Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in the
+#     documentation and/or other materials provided with the distribution.
+#  3. Neither the name of the copyright holder nor the
+#     names of its contributors may be used to endorse or promote products
+#     derived from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+#  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+#  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+#  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+#  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+#  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+#  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+#  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+#  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+#  POSSIBILITY OF SUCH DAMAGE.
+#
+
+source "tests/scripts/expect/_common.exp"
+
+
+set spawn_id [spawn_node 1]
+
+send "panid 0xface\n"
+expect "Done"
+send "ifconfig up\n"
+expect "Done"
+send "thread start\n"
+expect "Done"
+
+wait_for "state" "leader"
+expect "Done"
+
+send "ping fdde:ad00:beef:0:0:ff:fe00:fc00\n"
+expect "Done"
+expect "16 bytes from "
+expect {
+    "fdde:ad00:beef:0:0:ff:fe00:fc00" abort
+
+    -re {(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4})} {}
+
+    timeout abort
+}
+
+dispose

tests/scripts/expect/v1_2-rcp.exp

@@ -40,7 +40,7 @@ expect "Done"
 wait_for "state" "leader"
 expect "Done"
 
-send "ipaddr\n"
+send "ipaddr mleid\n"
 expect -re {(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4})}
 set addr $expect_out(1,string)
 expect "Done"