diff --git a/c_gen/c_test_gen.py b/c_gen/c_test_gen.py
index 5501ed3..aff1ca6 100644
--- a/c_gen/c_test_gen.py
+++ b/c_gen/c_test_gen.py
@@ -271,10 +271,8 @@
 
 """)
 
-    populate_match_version(1, match.of_v1_keys)
-    populate_match_version(2, match.of_v2_keys)
-    populate_match_version(3, match.match_keys_sorted)
-    populate_match_version(4, match.match_keys_sorted)
+    for wire_version, match_keys in match.match_keys.items():
+        populate_match_version(wire_version, match_keys)
 
     out.write("""
     if (value % 2) {
diff --git a/c_gen/match.py b/c_gen/match.py
index a7da751..7b7dcce 100644
--- a/c_gen/match.py
+++ b/c_gen/match.py
@@ -33,6 +33,7 @@
 import c_gen.of_g_legacy as of_g
 from generic_utils import *
 import c_gen.loxi_utils_legacy as loxi_utils
+import loxi_globals
 
 #
 # Use 1.2 match semantics for common case
@@ -47,512 +48,13 @@
 # Keys:
 #   name The unified name used for the member
 #   m_type The data type used for the object in unified structure
-#   print_type The id to use when printing
-#   conditions The condition underwhich the field could occur TBD
-#   takes_mask_in_spec Shown as taking mask in OF 1.2 spec; IGNORED NOW
 #   order Used to define an order for readability
 #   v1_wc_shift The WC shift in OF 1.0
 #   v2_wc_shift The WC shift in OF 1.1
 #
-# Unless noted otherwise, class is 0x8000, OFPXMC_OPENFLOW_BASIC
 # We use the 1.2 names and alias older names
-# Conditions:
-#  is_ipv4(_m):  ((_m)->eth_type == 0x0800)
-#  is_ipv6(_m):  ((_m)->eth_type == 0x86dd)
-#  is_ip(_m):    (is_ipv4(_m) || is_ipv6(_m))
-#  is_arp(_m):   ((_m)->eth_type == 0x0806)
-#  is_tcp(_m):   (is_ip(_m) && ((_m)->ip_proto == 6))
-#  is_udp(_m):   (is_ip(_m) && ((_m)->ip_proto == 17))
-#  is_sctp(_m):  (is_ip(_m) && ((_m)->ip_proto == 132))
-#  is_icmpv4(_m):  (is_ipv4(_m) && ((_m)->ip_proto == 1))
-#  is_icmpv6(_m):  (is_ipv6(_m) && ((_m)->ip_proto == 58))
-#
 
-of_match_members = dict(
-    in_port = dict(
-        name="in_port",
-        m_type="of_port_no_t",
-        print_type="PRIx32",
-        conditions="",
-        v1_wc_shift=0,
-        v2_wc_shift=0,
-        takes_mask_in_spec=False,
-        order=100,
-        ),
-    in_phy_port = dict(
-        name="in_phy_port",
-        m_type="of_port_no_t",
-        print_type="PRIx32",
-        conditions="", # OXM_OF_IN_PORT must be present
-        takes_mask_in_spec=False,
-        order=101,
-        ),
-    metadata = dict(
-        name="metadata",
-        m_type="uint64_t",
-        print_type="PRIx64",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=102,
-        ),
-
-    eth_dst = dict(
-        name="eth_dst",
-        m_type="of_mac_addr_t",
-        v1_wc_shift=3,
-        print_type="\"p\"",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=200,
-        ),
-    eth_src = dict(
-        name="eth_src",
-        m_type="of_mac_addr_t",
-        v1_wc_shift=2,
-        print_type="\"p\"",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=201,
-        ),
-    eth_type = dict(
-        name="eth_type",
-        m_type="uint16_t",
-        v1_wc_shift=4,
-        v2_wc_shift=3,
-        print_type="PRIx16",
-        conditions="",
-        takes_mask_in_spec=False,
-        order=203,
-        ),
-    vlan_vid = dict(  # FIXME: Semantics changed in 1.2
-        # Use CFI bit to indicate tag presence
-        name="vlan_vid",
-        m_type="uint16_t",
-        v1_wc_shift=1,
-        v2_wc_shift=1,
-        print_type="PRIx16",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=210,
-        ),
-    vlan_pcp = dict(
-        name="vlan_pcp",
-        m_type="uint8_t",
-        v1_wc_shift=20,
-        v2_wc_shift=2,
-        print_type="PRIx8",
-        conditions="",
-        takes_mask_in_spec=False,
-        order=211,
-        ),
-
-    ip_dscp = dict(
-        name="ip_dscp",
-        m_type="uint8_t",
-        v1_wc_shift=21,
-        v2_wc_shift=4,
-        print_type="PRIx8",
-        conditions="is_ip(match)",
-        takes_mask_in_spec=False,
-        order=310,
-        ),
-    ip_ecn = dict(
-        name="ip_ecn",
-        m_type="uint8_t",
-        print_type="PRIx8",
-        conditions="is_ip(match)",
-        takes_mask_in_spec=False,
-        order=311,
-        ),
-    ip_proto = dict(
-        name="ip_proto",
-        m_type="uint8_t",
-        v1_wc_shift=5,
-        v2_wc_shift=5,
-        print_type="PRIx8",
-        conditions="is_ip(match)",
-        takes_mask_in_spec=False,
-        order=320,
-        ),
-    ipv4_src = dict(
-        name="ipv4_src",
-        m_type="of_ipv4_t",
-        v1_wc_shift=8,
-        print_type="PRIx32",
-        conditions="is_ipv4(match)",
-        takes_mask_in_spec=True,
-        order=330,
-        ),
-    ipv4_dst = dict(
-        name="ipv4_dst",
-        m_type="of_ipv4_t",
-        v1_wc_shift=14,
-        print_type="PRIx32",
-        conditions="is_ipv4(match)",
-        takes_mask_in_spec=True,
-        order=331,
-        ),
-
-    tcp_dst = dict(
-        name="tcp_dst",
-        m_type="uint16_t",
-        v1_wc_shift=7,
-        v2_wc_shift=7,
-        print_type="PRIx16",
-        conditions="is_tcp(match)",
-        takes_mask_in_spec=False,
-        order=400,
-        ),
-    tcp_src = dict(
-        name="tcp_src",
-        m_type="uint16_t",
-        v1_wc_shift=6,
-        v2_wc_shift=6,
-        print_type="PRIx16",
-        conditions="is_tcp(match)",
-        takes_mask_in_spec=False,
-        order=401,
-        ),
-
-    udp_dst = dict(
-        name="udp_dst",
-        m_type="uint16_t",
-        print_type="PRIx16",
-        conditions="is_udp(match)",
-        takes_mask_in_spec=False,
-        order=410,
-        ),
-    udp_src = dict(
-        name="udp_src",
-        m_type="uint16_t",
-        print_type="PRIx16",
-        conditions="is_udp(match)",
-        takes_mask_in_spec=False,
-        order=411,
-        ),
-
-    sctp_dst = dict(
-        name="sctp_dst",
-        m_type="uint16_t",
-        print_type="PRIx16",
-        conditions="is_sctp(match)",
-        takes_mask_in_spec=False,
-        order=420,
-        ),
-    sctp_src = dict(
-        name="sctp_src",
-        m_type="uint16_t",
-        print_type="PRIx16",
-        conditions="is_sctp(match)",
-        takes_mask_in_spec=False,
-        order=421,
-        ),
-
-    icmpv4_type = dict(
-        name="icmpv4_type",
-        m_type="uint8_t",
-        print_type="PRIx8",
-        conditions="is_icmp_v4(match)",
-        takes_mask_in_spec=False,
-        order=430,
-        ),
-    icmpv4_code = dict(
-        name="icmpv4_code",
-        m_type="uint8_t",
-        print_type="PRIx8",
-        conditions="is_icmp_v4(match)",
-        takes_mask_in_spec=False,
-        order=431,
-        ),
-
-    arp_op = dict(
-        name="arp_op",
-        m_type="uint16_t",
-        print_type="PRIx16",
-        conditions="is_arp(match)",
-        takes_mask_in_spec=False,
-        order=450,
-        ),
-
-    arp_spa = dict(
-        name="arp_spa",
-        m_type="uint32_t",
-        print_type="PRIx32",
-        conditions="is_arp(match)",
-        takes_mask_in_spec=True,
-        order=451,
-        ),
-    arp_tpa = dict(
-        name="arp_tpa",
-        m_type="uint32_t",
-        print_type="PRIx32",
-        conditions="is_arp(match)",
-        takes_mask_in_spec=True,
-        order=452,
-        ),
-
-    arp_sha = dict(
-        name="arp_sha",
-        m_type="of_mac_addr_t",
-        print_type="\"p\"",
-        conditions="is_arp(match)",
-        takes_mask_in_spec=False,
-        order=453,
-        ),
-    arp_tha = dict(
-        name="arp_tha",
-        m_type="of_mac_addr_t",
-        print_type="\"p\"",
-        conditions="is_arp(match)",
-        takes_mask_in_spec=False,
-        order=454,
-        ),
-
-    ipv6_src = dict(
-        name="ipv6_src",
-        m_type="of_ipv6_t",
-        print_type="\"p\"",
-        conditions="is_ipv6(match)",
-        takes_mask_in_spec=True,
-        order=500,
-        ),
-    ipv6_dst = dict(
-        name="ipv6_dst",
-        m_type="of_ipv6_t",
-        print_type="\"p\"",
-        conditions="is_ipv6(match)",
-        takes_mask_in_spec=True,
-        order=501,
-        ),
-
-    ipv6_flabel = dict(
-        name="ipv6_flabel",
-        m_type="uint32_t",
-        print_type="PRIx32",
-        conditions="is_ipv6(match)",
-        takes_mask_in_spec=False, # Comment in openflow.h says True
-        order=502,
-        ),
-
-    icmpv6_type = dict(
-        name="icmpv6_type",
-        m_type="uint8_t",
-        print_type="PRIx8",
-        conditions="is_icmp_v6(match)",
-        takes_mask_in_spec=False,
-        order=510,
-        ),
-    icmpv6_code = dict(
-        name="icmpv6_code",
-        m_type="uint8_t",
-        print_type="PRIx8",
-        conditions="is_icmp_v6(match)",
-        takes_mask_in_spec=False,
-        order=511,
-        ),
-
-    ipv6_nd_target = dict(
-        name="ipv6_nd_target",
-        m_type="of_ipv6_t",
-        print_type="\"p\"",
-        conditions="", # fixme
-        takes_mask_in_spec=False,
-        order=512,
-        ),
-
-    ipv6_nd_sll = dict(
-        name="ipv6_nd_sll",
-        m_type="of_mac_addr_t",
-        print_type="\"p\"",
-        conditions="", # fixme
-        takes_mask_in_spec=False,
-        order=520,
-        ),
-    ipv6_nd_tll = dict(
-        name="ipv6_nd_tll",
-        m_type="of_mac_addr_t",
-        print_type="\"p\"",
-        conditions="", # fixme
-        takes_mask_in_spec=False,
-        order=521,
-        ),
-
-    mpls_label = dict(
-        name="mpls_label",
-        m_type="uint32_t",
-        v2_wc_shift=8,
-        print_type="PRIx32",
-        conditions="",
-        takes_mask_in_spec=False,
-        order=600,
-        ),
-    mpls_tc = dict(
-        name="mpls_tc",
-        m_type="uint8_t",
-        v2_wc_shift=9,
-        print_type="PRIx8",
-        conditions="",
-        takes_mask_in_spec=False,
-        order=601,
-        ),
-
-    bsn_in_ports_128 = dict(
-        name="bsn_in_ports_128",
-        m_type="of_bitmap_128_t",
-        v2_wc_shift=9,
-        print_type="p",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=1000,
-        ),
-
-    bsn_lag_id = dict(
-        name="bsn_lag_id",
-        m_type="uint32_t",
-        print_type="PRIu32",
-        conditions="",
-        takes_mask_in_spec=False,
-        order=1001,
-        ),
-
-    bsn_vrf = dict(
-        name="bsn_vrf",
-        m_type="uint32_t",
-        print_type="PRIu32",
-        conditions="",
-        takes_mask_in_spec=False,
-        order=1002,
-        ),
-
-    bsn_global_vrf_allowed = dict(
-        name="bsn_global_vrf_allowed",
-        m_type="uint8_t",
-        print_type="PRIu8",
-        conditions="",
-        takes_mask_in_spec=False,
-        order=1003,
-        ),
-
-    bsn_l3_interface_class_id = dict(
-        name="bsn_l3_interface_class_id",
-        m_type="uint32_t",
-        print_type="PRIu32",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=1003,
-        ),
-
-    bsn_l3_src_class_id = dict(
-        name="bsn_l3_src_class_id",
-        m_type="uint32_t",
-        print_type="PRIu32",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=1004,
-        ),
-
-    bsn_l3_dst_class_id = dict(
-        name="bsn_l3_dst_class_id",
-        m_type="uint32_t",
-        print_type="PRIu32",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=1005,
-        ),
-
-    bsn_egr_port_group_id = dict(
-        name="bsn_egr_port_group_id",
-        m_type="uint32_t",
-        print_type="PRIu32",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=1006,
-        ),
-
-    bsn_udf0 = dict(
-        name="bsn_udf0",
-        m_type="uint32_t",
-        print_type="PRIu32",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=1010,
-        ),
-
-    bsn_udf1 = dict(
-        name="bsn_udf1",
-        m_type="uint32_t",
-        print_type="PRIu32",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=1010,
-        ),
-
-    bsn_udf2 = dict(
-        name="bsn_udf2",
-        m_type="uint32_t",
-        print_type="PRIu32",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=1010,
-        ),
-
-    bsn_udf3 = dict(
-        name="bsn_udf3",
-        m_type="uint32_t",
-        print_type="PRIu32",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=1010,
-        ),
-
-    bsn_udf4 = dict(
-        name="bsn_udf4",
-        m_type="uint32_t",
-        print_type="PRIu32",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=1010,
-        ),
-
-    bsn_udf5 = dict(
-        name="bsn_udf5",
-        m_type="uint32_t",
-        print_type="PRIu32",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=1010,
-        ),
-
-    bsn_udf6 = dict(
-        name="bsn_udf6",
-        m_type="uint32_t",
-        print_type="PRIu32",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=1010,
-        ),
-
-    bsn_udf7 = dict(
-        name="bsn_udf7",
-        m_type="uint32_t",
-        print_type="PRIu32",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=1010,
-        ),
-
-    bsn_tcp_flags = dict(
-        name="bsn_tcp_flags",
-        m_type="uint16_t",
-        print_type="PRIx16",
-        conditions="",
-        takes_mask_in_spec=True,
-        order=1010,
-        ),
-)
-
-match_keys_sorted = of_match_members.keys()
-match_keys_sorted.sort(key=lambda entry:of_match_members[entry]["order"])
+of_match_members = dict()
 
 of_v1_keys = [
     "eth_dst",
@@ -569,6 +71,21 @@
     "vlan_vid"
     ]
 
+v1_wc_shifts = dict(
+    in_port=0,
+    vlan_vid=1,
+    eth_src=2,
+    eth_dst=3,
+    eth_type=4,
+    ip_proto=5,
+    tcp_src=6,
+    tcp_dst=7,
+    ipv4_src=8,
+    ipv4_dst=14,
+    vlan_pcp=20,
+    ip_dscp=21,
+)
+
 of_v2_keys = [
     "eth_dst",
     "eth_src",
@@ -595,6 +112,69 @@
     "metadata"
     ]
 
+v2_wc_shifts = dict(
+    in_port=0,
+    vlan_vid=1,
+    vlan_pcp=2,
+    eth_type=3,
+    ip_dscp=4,
+    ip_proto=5,
+    tcp_src=6,
+    tcp_dst=7,
+    mpls_label=8,
+    mpls_tc=9,
+)
+
+# Map from wire version to list of match keys for that version
+match_keys = {
+    1: of_v1_keys,
+    2: of_v2_keys,
+    3: [],
+    4: [],
+}
+
+# Complete list of match keys, sorted by the standard order
+match_keys_sorted = []
+
+# Generate the of_match_members, match_keys, and match_keys_sorted
+# datastructures from the IR and the v1/v2 tables above
+def build():
+    for uclass in loxi_globals.unified.classes:
+        if not uclass.is_oxm or uclass.name == 'of_oxm':
+            continue
+        if uclass.name.endswith('_masked'):
+            continue
+
+        name = uclass.name[7:] # of_oxm_*
+        value_member = uclass.member_by_name('value')
+        type_len = uclass.member_by_name('type_len').value
+
+        # Order match keys by their type_len
+        if (type_len & 0xffff0000) == 0x80000000:
+            # OpenFlow Basic comes first
+            order = type_len & 0x0000ffff
+        else:
+            order = type_len
+
+        match_member = dict(
+            name=name,
+            m_type=value_member.oftype,
+            order=order)
+        if name in v1_wc_shifts:
+            match_member['v1_wc_shift'] = v1_wc_shifts[name]
+        if name in v2_wc_shifts:
+            match_member['v2_wc_shift'] = v2_wc_shifts[name]
+
+        of_match_members[name] = match_member
+
+        for version in uclass.version_classes:
+            assert name not in match_keys[version.wire_version]
+            match_keys[version.wire_version].append(name)
+
+    match_keys_sorted.extend(
+        sorted(of_match_members.keys(),
+               key=lambda entry:of_match_members[entry]["order"]))
+
 ##
 # Check that all members in the hash are recognized as match keys
 def match_sanity_check():
diff --git a/lang_c.py b/lang_c.py
index 24ccc06..8e153fe 100644
--- a/lang_c.py
+++ b/lang_c.py
@@ -41,6 +41,7 @@
 import c_gen.c_show_gen as c_show_gen
 import c_gen.util
 import c_gen.codegen
+import c_gen.match
 import loxi_utils.loxi_utils as loxi_utils
 import template_utils
 
@@ -112,6 +113,7 @@
 }
 
 def generate(install_dir):
+    c_gen.match.build()
     build_of_g.initialize_versions()
     build_of_g.build_ordered_classes()
     build_of_g.populate_type_maps()