CSIT-197: Add basic mapping rule tests for MAP-E

- IPv4 prefix length + ea bits length < 32
- IPv4 prefix length + ea bits length == 32
- IPv4 prefix length + ea bits length > 32
- End user IPv6 prefix is 64
- IPv4 preffix is 0

Change-Id: Ib8d76abfebfb206fbbaa3c1422b2d321a3ed8712
Signed-off-by: Matej Klotton <mklotton@cisco.com>

1 files changed, 180 insertions, 0 deletions

diff --git a/resources/libraries/python/Map.py b/resources/libraries/python/Map.py
index 7d48c20d2e..b98d488e73 100644
--- a/resources/libraries/python/Map.py
+++ b/resources/libraries/python/Map.py
@@ -14,6 +14,8 @@
 """Map utilities library."""
 
 
+import ipaddress
+
 from resources.libraries.python.VatExecutor import VatExecutor
 
 
@@ -81,3 +83,181 @@ class Map(object):
         if output[0]["retval"] != 0:
             raise RuntimeError('Unable to add map rule on node {}'
                                .format(vpp_node['host']))
+
+    @staticmethod
+    def map_del_domain(vpp_node, index):
+        """Delete map domain on node.
+
+        :param vpp_node: VPP node to delete map domain on.
+        :param index: Index of the map domain.
+        :type vpp_node: dict
+        :type index: int
+        :raises RuntimeError: If unable to delete map domain.
+        """
+        output = VatExecutor.cmd_from_template(vpp_node, "map_del_domain.vat",
+                                               index=index)
+        if output[0]["retval"] != 0:
+            raise RuntimeError('Unable to delete map domain {} on node {}'
+                               .format(index, vpp_node['host']))
+
+    @staticmethod
+    def get_psid_from_port(port, psid_len, psid_offset):
+        """Return PSID from port.
+                              0                   1
+                              0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+                             +-----------+-----------+-------+
+               Ports in      |     A     |    PSID   |   j   |
+            the CE port set  |    > 0    |           |       |
+                             +-----------+-----------+-------+
+                             |  a bits   |  k bits   |m bits |
+
+
+        :param port: Port to compute PSID from.
+        :param psid_len: PSID length.
+        :param psid_offset: PSID offset.
+        :type port: int
+        :type psid_len: int
+        :type psid_offset: int
+
+        :return: PSID.
+        :rtype: int
+        """
+        ones = 2**16-1
+        mask = ones >> (16 - psid_len)
+        psid = port >> (16 - psid_len - psid_offset)
+        psid &= mask
+        return psid
+
+    @staticmethod
+    def _make_ea_bits(ipv4_net, ipv4_host, ea_bit_len, psid_len, psid):
+        """
+        _note_: host(or prefix) part of destination ip in rule prefix, + psid
+
+        :param ipv4_net: IPv4 domain prefix.
+        :param ipv4_host: Destination IPv4 address.
+        :param ea_bit_len: EA bit length.
+        :param psid_len: PSID length.
+        :param psid: PSID.
+        :type ipv4_net: ipaddress.IPv4Network
+        :type ipv4_host: ipaddress.IPv4Address
+        :type ea_bit_len: int
+        :type psid_len: int
+        :type psid: int
+        :return: Number representing EA bit field of destination IPv6 address.
+        :rtype: int
+        """
+        v4_suffix_len = ipv4_net._max_prefixlen - ipv4_net.prefixlen
+        v4_suffix = ipv4_net.network_address._ip ^ ipv4_host._ip
+
+        if ipv4_net.prefixlen + ea_bit_len <= 32:
+            ea_bits = v4_suffix >> (v4_suffix_len - ea_bit_len)
+            return ea_bits
+        else:
+            q_len = ea_bit_len - v4_suffix_len
+            # p_bits = v4_suffix << q_len  # option 1: psid right padded
+            p_bits = v4_suffix << psid_len  # option 2: psid left padded
+            if q_len < psid_len:
+                raise Exception("invalid configuration: q_len < psid_len")
+            ea_bits = p_bits | psid
+            ea_bits <<= q_len - psid_len  # option 2: psid left padded
+            return ea_bits
+
+    @staticmethod
+    def _make_interface_id(rule_net, dst_ip, ea_bit_len, psid):
+        """
+        _note_: if prefix or complete ip (<= 32), psid is 0
+
+        :param rule_net: IPv4 domain prefix.
+        :param dst_ip: Destination IPv4 address.
+        :param ea_bit_len: EA bit length.
+        :param psid: PSID.
+        :type rule_net: ipaddress.IPv4Network
+        :type dst_ip: ipaddress.IPv4Address
+        :type ea_bit_len: int
+        :type psid: int
+        :return: Number representing interface id field of destination IPv6
+        address.
+        :rtype: int
+        """
+        if rule_net.prefixlen + ea_bit_len < 32:
+            v4_suffix_len = rule_net._max_prefixlen - rule_net.prefixlen
+            v4_suffix = rule_net.network_address._ip ^ dst_ip._ip
+            ea_bits = v4_suffix >> (v4_suffix_len - ea_bit_len)
+            address = rule_net.network_address._ip >> v4_suffix_len
+            address <<= ea_bit_len
+            address |= ea_bits
+            address <<= 32 - rule_net.prefixlen - ea_bit_len
+            address <<= 16
+            # psid_field = 0
+            # address = address | psid_field
+        elif rule_net.prefixlen + ea_bit_len == 32:
+            address = dst_ip._ip << 16
+            # psid_field = 0
+            # address = address | psid_field
+        else:
+            address = dst_ip._ip << 16
+            address |= psid
+            return address
+
+        return address
+
+    @staticmethod
+    def compute_ipv6_map_destination_address(ipv4_pfx, ipv6_pfx, ea_bit_len,
+                                             psid_offset, psid_len, ipv4_dst,
+                                             dst_port):
+        """Compute IPv6 destination address from IPv4 address for MAP algorithm.
+        (RFC 7597)
+
+       |     n bits         |  o bits   | s bits  |   128-n-o-s bits      |
+       +--------------------+-----------+---------+-----------------------+
+       |  Rule IPv6 prefix  |  EA bits  |subnet ID|     interface ID      |
+       +--------------------+-----------+---------+-----------------------+
+       |<---  End-user IPv6 prefix  --->|
+
+
+        :param ipv4_pfx: Domain IPv4 preffix.
+        :param ipv6_pfx: Domain IPv6 preffix.
+        :param ea_bit_len: Domain EA bits length.
+        :param psid_offset: Domain PSID offset.
+        :param psid_len: Domain PSID length.
+        :param ipv4_dst: Destination IPv4 address.
+        :param dst_port: Destination port number or ICMP ID.
+        :type ipv4_pfx: str
+        :type ipv6_pfx: str
+        :type ea_bit_len: int
+        :type psid_offset: int
+        :type psid_len: int
+        :type ipv4_dst: str
+        :type dst_port: int
+        :return: Computed IPv6 address.
+        :rtype: str
+        """
+        ipv6_net = ipaddress.ip_network(unicode(ipv6_pfx))
+        ipv4_net = ipaddress.ip_network(unicode(ipv4_pfx))
+        ipv4_host = ipaddress.ip_address(unicode(ipv4_dst))
+
+        ipv6_host_len = ipv6_net._max_prefixlen - ipv6_net.prefixlen
+        ipv4_host_len = ipv4_net._max_prefixlen - ipv4_net.prefixlen
+        end_user_v6_pfx_len = ipv6_net.prefixlen + ea_bit_len
+        psid = Map.get_psid_from_port(dst_port, psid_len, psid_offset)
+
+        rule_v6_pfx = ipv6_net.network_address._ip >> ipv6_host_len
+        ea_bits = Map._make_ea_bits(ipv4_net, ipv4_host, ea_bit_len, psid_len,
+                                    psid)
+        subnet_id = 0
+        interface_id = Map._make_interface_id(ipv4_net, ipv4_host, ea_bit_len,
+                                              psid)
+
+        address = rule_v6_pfx << ea_bit_len
+        address |= ea_bits  # add EA bits
+
+        if end_user_v6_pfx_len > 64:
+            # If the End-user IPv6 prefix length is larger than 64,
+            # the most significant parts of the interface identifier are
+            # overwritten by the prefix.
+            mask = (2**128-1) >> end_user_v6_pfx_len
+            interface_id &= mask
+        address <<= (128 - end_user_v6_pfx_len)
+        address |= interface_id  # add Interface ID bits
+
+        return str(ipaddress.ip_address(address))