Merge 'master' into 'next'.
[sliver-openvswitch.git] / lib / ofp-util.c
index 99ef722..3487cba 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
 
 #include <config.h>
 #include "ofp-print.h"
+#include <errno.h>
 #include <inttypes.h>
 #include <stdlib.h>
+#include "autopath.h"
 #include "byte-order.h"
 #include "classifier.h"
+#include "dynamic-string.h"
+#include "multipath.h"
 #include "nx-match.h"
+#include "ofp-errors.h"
 #include "ofp-util.h"
 #include "ofpbuf.h"
 #include "packets.h"
 #include "random.h"
+#include "unaligned.h"
+#include "type-props.h"
 #include "vlog.h"
 
 VLOG_DEFINE_THIS_MODULE(ofp_util);
@@ -95,43 +102,32 @@ enum {
 };
 
 /* Converts the ofp_match in 'match' into a cls_rule in 'rule', with the given
- * 'priority'.
- *
- * 'flow_format' must either NXFF_OPENFLOW10 or NXFF_TUN_ID_FROM_COOKIE.  In
- * the latter case only, 'flow''s tun_id field will be taken from the high bits
- * of 'cookie', if 'match''s wildcards do not indicate that tun_id is
- * wildcarded. */
+ * 'priority'. */
 void
 ofputil_cls_rule_from_match(const struct ofp_match *match,
-                            unsigned int priority,
-                            enum nx_flow_format flow_format,
-                            uint64_t cookie, struct cls_rule *rule)
+                            unsigned int priority, struct cls_rule *rule)
 {
     struct flow_wildcards *wc = &rule->wc;
     unsigned int ofpfw;
     ovs_be16 vid, pcp;
 
     /* Initialize rule->priority. */
-    ofpfw = ntohl(match->wildcards);
-    ofpfw &= flow_format == NXFF_TUN_ID_FROM_COOKIE ? OVSFW_ALL : OFPFW_ALL;
+    ofpfw = ntohl(match->wildcards) & OFPFW_ALL;
     rule->priority = !ofpfw ? UINT16_MAX : priority;
 
     /* Initialize most of rule->wc. */
+    flow_wildcards_init_catchall(wc);
     wc->wildcards = ofpfw & WC_INVARIANTS;
+
+    /* Wildcard fields that aren't defined by ofp_match or tun_id. */
+    wc->wildcards |= (FWW_ARP_SHA | FWW_ARP_THA | FWW_ND_TARGET);
+
     if (ofpfw & OFPFW_NW_TOS) {
         wc->wildcards |= FWW_NW_TOS;
     }
-    memset(wc->reg_masks, 0, sizeof wc->reg_masks);
     wc->nw_src_mask = ofputil_wcbits_to_netmask(ofpfw >> OFPFW_NW_SRC_SHIFT);
     wc->nw_dst_mask = ofputil_wcbits_to_netmask(ofpfw >> OFPFW_NW_DST_SHIFT);
 
-    if (flow_format == NXFF_TUN_ID_FROM_COOKIE && !(ofpfw & NXFW_TUN_ID)) {
-        rule->flow.tun_id = htonl(ntohll(cookie) >> 32);
-    } else {
-        wc->wildcards |= FWW_TUN_ID;
-        rule->flow.tun_id = 0;
-    }
-
     if (ofpfw & OFPFW_DL_DST) {
         /* OpenFlow 1.0 OFPFW_DL_DST covers the whole Ethernet destination, but
          * Open vSwitch breaks the Ethernet destination into bits as FWW_DL_DST
@@ -142,9 +138,8 @@ ofputil_cls_rule_from_match(const struct ofp_match *match,
     /* Initialize most of rule->flow. */
     rule->flow.nw_src = match->nw_src;
     rule->flow.nw_dst = match->nw_dst;
-    rule->flow.in_port = (match->in_port == htons(OFPP_LOCAL) ? ODPP_LOCAL
-                     : ntohs(match->in_port));
-    rule->flow.dl_type = match->dl_type;
+    rule->flow.in_port = ntohs(match->in_port);
+    rule->flow.dl_type = ofputil_dl_type_from_openflow(match->dl_type);
     rule->flow.tp_src = match->tp_src;
     rule->flow.tp_dst = match->tp_dst;
     memcpy(rule->flow.dl_src, match->dl_src, ETH_ADDR_LEN);
@@ -199,16 +194,9 @@ ofputil_cls_rule_from_match(const struct ofp_match *match,
     cls_rule_zero_wildcarded_fields(rule);
 }
 
-/* Extract 'flow' with 'wildcards' into the OpenFlow match structure
- * 'match'.
- *
- * 'flow_format' must either NXFF_OPENFLOW10 or NXFF_TUN_ID_FROM_COOKIE.  In
- * the latter case only, 'match''s NXFW_TUN_ID bit will be filled in; otherwise
- * it is always set to 0. */
+/* Convert 'rule' into the OpenFlow match structure 'match'. */
 void
-ofputil_cls_rule_to_match(const struct cls_rule *rule,
-                          enum nx_flow_format flow_format,
-                          struct ofp_match *match)
+ofputil_cls_rule_to_match(const struct cls_rule *rule, struct ofp_match *match)
 {
     const struct flow_wildcards *wc = &rule->wc;
     unsigned int ofpfw;
@@ -220,9 +208,6 @@ ofputil_cls_rule_to_match(const struct cls_rule *rule,
     if (wc->wildcards & FWW_NW_TOS) {
         ofpfw |= OFPFW_NW_TOS;
     }
-    if (flow_format == NXFF_TUN_ID_FROM_COOKIE && wc->wildcards & FWW_TUN_ID) {
-        ofpfw |= NXFW_TUN_ID;
-    }
 
     /* Translate VLANs. */
     match->dl_vlan = htons(0);
@@ -248,11 +233,10 @@ ofputil_cls_rule_to_match(const struct cls_rule *rule,
 
     /* Compose most of the match structure. */
     match->wildcards = htonl(ofpfw);
-    match->in_port = htons(rule->flow.in_port == ODPP_LOCAL ? OFPP_LOCAL
-                           : rule->flow.in_port);
+    match->in_port = htons(rule->flow.in_port);
     memcpy(match->dl_src, rule->flow.dl_src, ETH_ADDR_LEN);
     memcpy(match->dl_dst, rule->flow.dl_dst, ETH_ADDR_LEN);
-    match->dl_type = rule->flow.dl_type;
+    match->dl_type = ofputil_dl_type_to_openflow(rule->flow.dl_type);
     match->nw_src = rule->flow.nw_src;
     match->nw_dst = rule->flow.nw_dst;
     match->nw_tos = rule->flow.nw_tos;
@@ -263,6 +247,27 @@ ofputil_cls_rule_to_match(const struct cls_rule *rule,
     memset(match->pad2, '\0', sizeof match->pad2);
 }
 
+/* Given a 'dl_type' value in the format used in struct flow, returns the
+ * corresponding 'dl_type' value for use in an OpenFlow ofp_match structure. */
+ovs_be16
+ofputil_dl_type_to_openflow(ovs_be16 flow_dl_type)
+{
+    return (flow_dl_type == htons(FLOW_DL_TYPE_NONE)
+            ? htons(OFP_DL_TYPE_NOT_ETH_TYPE)
+            : flow_dl_type);
+}
+
+/* Given a 'dl_type' value in the format used in an OpenFlow ofp_match
+ * structure, returns the corresponding 'dl_type' value for use in struct
+ * flow. */
+ovs_be16
+ofputil_dl_type_from_openflow(ovs_be16 ofp_dl_type)
+{
+    return (ofp_dl_type == htons(OFP_DL_TYPE_NOT_ETH_TYPE)
+            ? htons(FLOW_DL_TYPE_NONE)
+            : ofp_dl_type);
+}
+
 /* Returns a transaction ID to use for an outgoing OpenFlow message. */
 static ovs_be32
 alloc_xid(void)
@@ -270,7 +275,1149 @@ alloc_xid(void)
     static uint32_t next_xid = 1;
     return htonl(next_xid++);
 }
+\f
+/* Basic parsing of OpenFlow messages. */
+
+struct ofputil_msg_type {
+    enum ofputil_msg_code code; /* OFPUTIL_*. */
+    uint32_t value;             /* OFPT_*, OFPST_*, NXT_*, or NXST_*. */
+    const char *name;           /* e.g. "OFPT_FLOW_REMOVED". */
+    unsigned int min_size;      /* Minimum total message size in bytes. */
+    /* 0 if 'min_size' is the exact size that the message must be.  Otherwise,
+     * the message may exceed 'min_size' by an even multiple of this value. */
+    unsigned int extra_multiple;
+};
+
+struct ofputil_msg_category {
+    const char *name;           /* e.g. "OpenFlow message" */
+    const struct ofputil_msg_type *types;
+    size_t n_types;
+    int missing_error;          /* ofp_mkerr() value for missing type. */
+};
+
+static bool
+ofputil_length_ok(const struct ofputil_msg_category *cat,
+                  const struct ofputil_msg_type *type,
+                  unsigned int size)
+{
+    switch (type->extra_multiple) {
+    case 0:
+        if (size != type->min_size) {
+            VLOG_WARN_RL(&bad_ofmsg_rl, "received %s %s with incorrect "
+                         "length %u (expected length %u)",
+                         cat->name, type->name, size, type->min_size);
+            return false;
+        }
+        return true;
+
+    case 1:
+        if (size < type->min_size) {
+            VLOG_WARN_RL(&bad_ofmsg_rl, "received %s %s with incorrect "
+                         "length %u (expected length at least %u bytes)",
+                         cat->name, type->name, size, type->min_size);
+            return false;
+        }
+        return true;
+
+    default:
+        if (size < type->min_size
+            || (size - type->min_size) % type->extra_multiple) {
+            VLOG_WARN_RL(&bad_ofmsg_rl, "received %s %s with incorrect "
+                         "length %u (must be exactly %u bytes or longer "
+                         "by an integer multiple of %u bytes)",
+                         cat->name, type->name, size,
+                         type->min_size, type->extra_multiple);
+            return false;
+        }
+        return true;
+    }
+}
+
+static int
+ofputil_lookup_openflow_message(const struct ofputil_msg_category *cat,
+                                uint32_t value, unsigned int size,
+                                const struct ofputil_msg_type **typep)
+{
+    const struct ofputil_msg_type *type;
+    bool found;
+
+    found = false;
+    for (type = cat->types; type < &cat->types[cat->n_types]; type++) {
+        if (type->value == value) {
+            if (ofputil_length_ok(cat, type, size)) {
+                *typep = type;
+                return 0;
+            }
+
+            /* We found a matching command type but it had the wrong length.
+             * Probably this is just an error.  However, a screwup means that
+             * NXT_SET_FLOW_FORMAT and NXT_FLOW_MOD_TABLE_ID have the same
+             * value.  They do have different lengths, so we can distinguish
+             * them that way. */
+            found = true;
+        }
+    }
+    if (found) {
+        return ofp_mkerr(OFPET_BAD_REQUEST, OFPBRC_BAD_LEN);
+    }
+
+    VLOG_WARN_RL(&bad_ofmsg_rl, "received %s of unknown type %"PRIu32,
+                 cat->name, value);
+    return cat->missing_error;
+}
+
+static int
+ofputil_decode_vendor(const struct ofp_header *oh,
+                      const struct ofputil_msg_type **typep)
+{
+    BUILD_ASSERT_DECL(sizeof(struct nxt_set_flow_format)
+                      != sizeof(struct nxt_flow_mod_table_id));
+
+    static const struct ofputil_msg_type nxt_messages[] = {
+        { OFPUTIL_NXT_ROLE_REQUEST,
+          NXT_ROLE_REQUEST, "NXT_ROLE_REQUEST",
+          sizeof(struct nx_role_request), 0 },
+
+        { OFPUTIL_NXT_ROLE_REPLY,
+          NXT_ROLE_REPLY, "NXT_ROLE_REPLY",
+          sizeof(struct nx_role_request), 0 },
+
+        { OFPUTIL_NXT_SET_FLOW_FORMAT,
+          NXT_SET_FLOW_FORMAT, "NXT_SET_FLOW_FORMAT",
+          sizeof(struct nxt_set_flow_format), 0 },
+
+        { OFPUTIL_NXT_FLOW_MOD_TABLE_ID,
+          NXT_FLOW_MOD_TABLE_ID, "NXT_FLOW_MOD_TABLE_ID",
+          sizeof(struct nxt_flow_mod_table_id), 0 },
+
+        { OFPUTIL_NXT_FLOW_MOD,
+          NXT_FLOW_MOD, "NXT_FLOW_MOD",
+          sizeof(struct nx_flow_mod), 8 },
+
+        { OFPUTIL_NXT_FLOW_REMOVED,
+          NXT_FLOW_REMOVED, "NXT_FLOW_REMOVED",
+          sizeof(struct nx_flow_removed), 8 },
+    };
+
+    static const struct ofputil_msg_category nxt_category = {
+        "Nicira extension message",
+        nxt_messages, ARRAY_SIZE(nxt_messages),
+        OFP_MKERR(OFPET_BAD_REQUEST, OFPBRC_BAD_SUBTYPE)
+    };
+
+    const struct ofp_vendor_header *ovh;
+    const struct nicira_header *nh;
+
+    ovh = (const struct ofp_vendor_header *) oh;
+    if (ovh->vendor != htonl(NX_VENDOR_ID)) {
+        VLOG_WARN_RL(&bad_ofmsg_rl, "received vendor message for unknown "
+                     "vendor %"PRIx32, ntohl(ovh->vendor));
+        return ofp_mkerr(OFPET_BAD_REQUEST, OFPBRC_BAD_VENDOR);
+    }
+
+    if (ntohs(ovh->header.length) < sizeof(struct nicira_header)) {
+        VLOG_WARN_RL(&bad_ofmsg_rl, "received Nicira vendor message of "
+                     "length %u (expected at least %zu)",
+                     ntohs(ovh->header.length), sizeof(struct nicira_header));
+        return ofp_mkerr(OFPET_BAD_REQUEST, OFPBRC_BAD_LEN);
+    }
+
+    nh = (const struct nicira_header *) oh;
+    return ofputil_lookup_openflow_message(&nxt_category, ntohl(nh->subtype),
+                                           ntohs(oh->length), typep);
+}
+
+static int
+check_nxstats_msg(const struct ofp_header *oh)
+{
+    const struct ofp_stats_request *osr;
+    ovs_be32 vendor;
+
+    osr = (const struct ofp_stats_request *) oh;
+
+    memcpy(&vendor, osr->body, sizeof vendor);
+    if (vendor != htonl(NX_VENDOR_ID)) {
+        VLOG_WARN_RL(&bad_ofmsg_rl, "received vendor stats message for "
+                     "unknown vendor %"PRIx32, ntohl(vendor));
+        return ofp_mkerr(OFPET_BAD_REQUEST, OFPBRC_BAD_VENDOR);
+    }
+
+    if (ntohs(osr->header.length) < sizeof(struct nicira_stats_msg)) {
+        VLOG_WARN_RL(&bad_ofmsg_rl, "truncated Nicira stats message");
+        return ofp_mkerr(OFPET_BAD_REQUEST, OFPBRC_BAD_LEN);
+    }
+
+    return 0;
+}
+
+static int
+ofputil_decode_nxst_request(const struct ofp_header *oh,
+                            const struct ofputil_msg_type **typep)
+{
+    static const struct ofputil_msg_type nxst_requests[] = {
+        { OFPUTIL_NXST_FLOW_REQUEST,
+          NXST_FLOW, "NXST_FLOW request",
+          sizeof(struct nx_flow_stats_request), 8 },
+
+        { OFPUTIL_NXST_AGGREGATE_REQUEST,
+          NXST_AGGREGATE, "NXST_AGGREGATE request",
+          sizeof(struct nx_aggregate_stats_request), 8 },
+    };
+
+    static const struct ofputil_msg_category nxst_request_category = {
+        "Nicira extension statistics request",
+        nxst_requests, ARRAY_SIZE(nxst_requests),
+        OFP_MKERR(OFPET_BAD_REQUEST, OFPBRC_BAD_SUBTYPE)
+    };
+
+    const struct nicira_stats_msg *nsm;
+    int error;
+
+    error = check_nxstats_msg(oh);
+    if (error) {
+        return error;
+    }
+
+    nsm = (struct nicira_stats_msg *) oh;
+    return ofputil_lookup_openflow_message(&nxst_request_category,
+                                           ntohl(nsm->subtype),
+                                           ntohs(oh->length), typep);
+}
+
+static int
+ofputil_decode_nxst_reply(const struct ofp_header *oh,
+                          const struct ofputil_msg_type **typep)
+{
+    static const struct ofputil_msg_type nxst_replies[] = {
+        { OFPUTIL_NXST_FLOW_REPLY,
+          NXST_FLOW, "NXST_FLOW reply",
+          sizeof(struct nicira_stats_msg), 8 },
+
+        { OFPUTIL_NXST_AGGREGATE_REPLY,
+          NXST_AGGREGATE, "NXST_AGGREGATE reply",
+          sizeof(struct nx_aggregate_stats_reply), 0 },
+    };
+
+    static const struct ofputil_msg_category nxst_reply_category = {
+        "Nicira extension statistics reply",
+        nxst_replies, ARRAY_SIZE(nxst_replies),
+        OFP_MKERR(OFPET_BAD_REQUEST, OFPBRC_BAD_SUBTYPE)
+    };
+
+    const struct nicira_stats_msg *nsm;
+    int error;
+
+    error = check_nxstats_msg(oh);
+    if (error) {
+        return error;
+    }
+
+    nsm = (struct nicira_stats_msg *) oh;
+    return ofputil_lookup_openflow_message(&nxst_reply_category,
+                                           ntohl(nsm->subtype),
+                                           ntohs(oh->length), typep);
+}
+
+static int
+ofputil_decode_ofpst_request(const struct ofp_header *oh,
+                             const struct ofputil_msg_type **typep)
+{
+    enum { OSR_SIZE = sizeof(struct ofp_stats_request) };
+    static const struct ofputil_msg_type ofpst_requests[] = {
+        { OFPUTIL_OFPST_DESC_REQUEST,
+          OFPST_DESC, "OFPST_DESC request",
+          OSR_SIZE, 0 },
+
+        { OFPUTIL_OFPST_FLOW_REQUEST,
+          OFPST_FLOW, "OFPST_FLOW request",
+          OSR_SIZE + sizeof(struct ofp_flow_stats_request), 0 },
+
+        { OFPUTIL_OFPST_AGGREGATE_REQUEST,
+          OFPST_AGGREGATE, "OFPST_AGGREGATE request",
+          OSR_SIZE + sizeof(struct ofp_aggregate_stats_request), 0 },
+
+        { OFPUTIL_OFPST_TABLE_REQUEST,
+          OFPST_TABLE, "OFPST_TABLE request",
+          OSR_SIZE, 0 },
+
+        { OFPUTIL_OFPST_PORT_REQUEST,
+          OFPST_PORT, "OFPST_PORT request",
+          OSR_SIZE + sizeof(struct ofp_port_stats_request), 0 },
+
+        { OFPUTIL_OFPST_QUEUE_REQUEST,
+          OFPST_QUEUE, "OFPST_QUEUE request",
+          OSR_SIZE + sizeof(struct ofp_queue_stats_request), 0 },
+
+        { 0,
+          OFPST_VENDOR, "OFPST_VENDOR request",
+          OSR_SIZE + sizeof(uint32_t), 1 },
+    };
+
+    static const struct ofputil_msg_category ofpst_request_category = {
+        "OpenFlow statistics",
+        ofpst_requests, ARRAY_SIZE(ofpst_requests),
+        OFP_MKERR(OFPET_BAD_REQUEST, OFPBRC_BAD_STAT)
+    };
+
+    const struct ofp_stats_request *osr;
+    int error;
+
+    osr = (const struct ofp_stats_request *) oh;
+    error = ofputil_lookup_openflow_message(&ofpst_request_category,
+                                            ntohs(osr->type),
+                                            ntohs(oh->length), typep);
+    if (!error && osr->type == htons(OFPST_VENDOR)) {
+        error = ofputil_decode_nxst_request(oh, typep);
+    }
+    return error;
+}
+
+static int
+ofputil_decode_ofpst_reply(const struct ofp_header *oh,
+                           const struct ofputil_msg_type **typep)
+{
+    enum { OSR_SIZE = sizeof(struct ofp_stats_reply) };
+    static const struct ofputil_msg_type ofpst_replies[] = {
+        { OFPUTIL_OFPST_DESC_REPLY,
+          OFPST_DESC, "OFPST_DESC reply",
+          OSR_SIZE + sizeof(struct ofp_desc_stats), 0 },
+
+        { OFPUTIL_OFPST_FLOW_REPLY,
+          OFPST_FLOW, "OFPST_FLOW reply",
+          OSR_SIZE, 1 },
+
+        { OFPUTIL_OFPST_AGGREGATE_REPLY,
+          OFPST_AGGREGATE, "OFPST_AGGREGATE reply",
+          OSR_SIZE + sizeof(struct ofp_aggregate_stats_reply), 0 },
+
+        { OFPUTIL_OFPST_TABLE_REPLY,
+          OFPST_TABLE, "OFPST_TABLE reply",
+          OSR_SIZE, sizeof(struct ofp_table_stats) },
+
+        { OFPUTIL_OFPST_PORT_REPLY,
+          OFPST_PORT, "OFPST_PORT reply",
+          OSR_SIZE, sizeof(struct ofp_port_stats) },
+
+        { OFPUTIL_OFPST_QUEUE_REPLY,
+          OFPST_QUEUE, "OFPST_QUEUE reply",
+          OSR_SIZE, sizeof(struct ofp_queue_stats) },
+
+        { 0,
+          OFPST_VENDOR, "OFPST_VENDOR reply",
+          OSR_SIZE + sizeof(uint32_t), 1 },
+    };
+
+    static const struct ofputil_msg_category ofpst_reply_category = {
+        "OpenFlow statistics",
+        ofpst_replies, ARRAY_SIZE(ofpst_replies),
+        OFP_MKERR(OFPET_BAD_REQUEST, OFPBRC_BAD_STAT)
+    };
+
+    const struct ofp_stats_reply *osr = (const struct ofp_stats_reply *) oh;
+    int error;
+
+    error = ofputil_lookup_openflow_message(&ofpst_reply_category,
+                                           ntohs(osr->type),
+                                           ntohs(oh->length), typep);
+    if (!error && osr->type == htons(OFPST_VENDOR)) {
+        error = ofputil_decode_nxst_reply(oh, typep);
+    }
+    return error;
+}
+
+/* Decodes the message type represented by 'oh'.  Returns 0 if successful or
+ * an OpenFlow error code constructed with ofp_mkerr() on failure.  Either
+ * way, stores in '*typep' a type structure that can be inspected with the
+ * ofputil_msg_type_*() functions.
+ *
+ * oh->length must indicate the correct length of the message (and must be at
+ * least sizeof(struct ofp_header)).
+ *
+ * Success indicates that 'oh' is at least as long as the minimum-length
+ * message of its type. */
+int
+ofputil_decode_msg_type(const struct ofp_header *oh,
+                        const struct ofputil_msg_type **typep)
+{
+    static const struct ofputil_msg_type ofpt_messages[] = {
+        { OFPUTIL_OFPT_HELLO,
+          OFPT_HELLO, "OFPT_HELLO",
+          sizeof(struct ofp_hello), 1 },
+
+        { OFPUTIL_OFPT_ERROR,
+          OFPT_ERROR, "OFPT_ERROR",
+          sizeof(struct ofp_error_msg), 1 },
+
+        { OFPUTIL_OFPT_ECHO_REQUEST,
+          OFPT_ECHO_REQUEST, "OFPT_ECHO_REQUEST",
+          sizeof(struct ofp_header), 1 },
+
+        { OFPUTIL_OFPT_ECHO_REPLY,
+          OFPT_ECHO_REPLY, "OFPT_ECHO_REPLY",
+          sizeof(struct ofp_header), 1 },
+
+        { OFPUTIL_OFPT_FEATURES_REQUEST,
+          OFPT_FEATURES_REQUEST, "OFPT_FEATURES_REQUEST",
+          sizeof(struct ofp_header), 0 },
+
+        { OFPUTIL_OFPT_FEATURES_REPLY,
+          OFPT_FEATURES_REPLY, "OFPT_FEATURES_REPLY",
+          sizeof(struct ofp_switch_features), sizeof(struct ofp_phy_port) },
+
+        { OFPUTIL_OFPT_GET_CONFIG_REQUEST,
+          OFPT_GET_CONFIG_REQUEST, "OFPT_GET_CONFIG_REQUEST",
+          sizeof(struct ofp_header), 0 },
+
+        { OFPUTIL_OFPT_GET_CONFIG_REPLY,
+          OFPT_GET_CONFIG_REPLY, "OFPT_GET_CONFIG_REPLY",
+          sizeof(struct ofp_switch_config), 0 },
+
+        { OFPUTIL_OFPT_SET_CONFIG,
+          OFPT_SET_CONFIG, "OFPT_SET_CONFIG",
+          sizeof(struct ofp_switch_config), 0 },
+
+        { OFPUTIL_OFPT_PACKET_IN,
+          OFPT_PACKET_IN, "OFPT_PACKET_IN",
+          offsetof(struct ofp_packet_in, data), 1 },
+
+        { OFPUTIL_OFPT_FLOW_REMOVED,
+          OFPT_FLOW_REMOVED, "OFPT_FLOW_REMOVED",
+          sizeof(struct ofp_flow_removed), 0 },
+
+        { OFPUTIL_OFPT_PORT_STATUS,
+          OFPT_PORT_STATUS, "OFPT_PORT_STATUS",
+          sizeof(struct ofp_port_status), 0 },
+
+        { OFPUTIL_OFPT_PACKET_OUT,
+          OFPT_PACKET_OUT, "OFPT_PACKET_OUT",
+          sizeof(struct ofp_packet_out), 1 },
+
+        { OFPUTIL_OFPT_FLOW_MOD,
+          OFPT_FLOW_MOD, "OFPT_FLOW_MOD",
+          sizeof(struct ofp_flow_mod), 1 },
+
+        { OFPUTIL_OFPT_PORT_MOD,
+          OFPT_PORT_MOD, "OFPT_PORT_MOD",
+          sizeof(struct ofp_port_mod), 0 },
+
+        { 0,
+          OFPT_STATS_REQUEST, "OFPT_STATS_REQUEST",
+          sizeof(struct ofp_stats_request), 1 },
+
+        { 0,
+          OFPT_STATS_REPLY, "OFPT_STATS_REPLY",
+          sizeof(struct ofp_stats_reply), 1 },
+
+        { OFPUTIL_OFPT_BARRIER_REQUEST,
+          OFPT_BARRIER_REQUEST, "OFPT_BARRIER_REQUEST",
+          sizeof(struct ofp_header), 0 },
+
+        { OFPUTIL_OFPT_BARRIER_REPLY,
+          OFPT_BARRIER_REPLY, "OFPT_BARRIER_REPLY",
+          sizeof(struct ofp_header), 0 },
+
+        { 0,
+          OFPT_VENDOR, "OFPT_VENDOR",
+          sizeof(struct ofp_vendor_header), 1 },
+    };
+
+    static const struct ofputil_msg_category ofpt_category = {
+        "OpenFlow message",
+        ofpt_messages, ARRAY_SIZE(ofpt_messages),
+        OFP_MKERR(OFPET_BAD_REQUEST, OFPBRC_BAD_TYPE)
+    };
+
+    int error;
+
+    error = ofputil_lookup_openflow_message(&ofpt_category, oh->type,
+                                            ntohs(oh->length), typep);
+    if (!error) {
+        switch (oh->type) {
+        case OFPT_VENDOR:
+            error = ofputil_decode_vendor(oh, typep);
+            break;
+
+        case OFPT_STATS_REQUEST:
+            error = ofputil_decode_ofpst_request(oh, typep);
+            break;
+
+        case OFPT_STATS_REPLY:
+            error = ofputil_decode_ofpst_reply(oh, typep);
+
+        default:
+            break;
+        }
+    }
+    if (error) {
+        static const struct ofputil_msg_type ofputil_invalid_type = {
+            OFPUTIL_INVALID,
+            0, "OFPUTIL_INVALID",
+            0, 0
+        };
+
+        *typep = &ofputil_invalid_type;
+    }
+    return error;
+}
+
+/* Returns an OFPUTIL_* message type code for 'type'. */
+enum ofputil_msg_code
+ofputil_msg_type_code(const struct ofputil_msg_type *type)
+{
+    return type->code;
+}
+\f
+/* Flow formats. */
+
+bool
+ofputil_flow_format_is_valid(enum nx_flow_format flow_format)
+{
+    switch (flow_format) {
+    case NXFF_OPENFLOW10:
+    case NXFF_NXM:
+        return true;
+    }
+
+    return false;
+}
+
+const char *
+ofputil_flow_format_to_string(enum nx_flow_format flow_format)
+{
+    switch (flow_format) {
+    case NXFF_OPENFLOW10:
+        return "openflow10";
+    case NXFF_NXM:
+        return "nxm";
+    default:
+        NOT_REACHED();
+    }
+}
+
+int
+ofputil_flow_format_from_string(const char *s)
+{
+    return (!strcmp(s, "openflow10") ? NXFF_OPENFLOW10
+            : !strcmp(s, "nxm") ? NXFF_NXM
+            : -1);
+}
+
+static bool
+regs_fully_wildcarded(const struct flow_wildcards *wc)
+{
+    int i;
+
+    for (i = 0; i < FLOW_N_REGS; i++) {
+        if (wc->reg_masks[i] != 0) {
+            return false;
+        }
+    }
+    return true;
+}
+
+/* Returns the minimum nx_flow_format to use for sending 'rule' to a switch
+ * (e.g. to add or remove a flow).  Only NXM can handle tunnel IDs, registers,
+ * or fixing the Ethernet multicast bit.  Otherwise, it's better to use
+ * NXFF_OPENFLOW10 for backward compatibility. */
+enum nx_flow_format
+ofputil_min_flow_format(const struct cls_rule *rule)
+{
+    const struct flow_wildcards *wc = &rule->wc;
+
+    /* Only NXM supports separately wildcards the Ethernet multicast bit. */
+    if (!(wc->wildcards & FWW_DL_DST) != !(wc->wildcards & FWW_ETH_MCAST)) {
+        return NXFF_NXM;
+    }
+
+    /* Only NXM supports matching ARP hardware addresses. */
+    if (!(wc->wildcards & FWW_ARP_SHA) || !(wc->wildcards & FWW_ARP_THA)) {
+        return NXFF_NXM;
+    }
+
+    /* Only NXM supports matching IPv6 traffic. */
+    if (!(wc->wildcards & FWW_DL_TYPE)
+            && (rule->flow.dl_type == htons(ETH_TYPE_IPV6))) {
+        return NXFF_NXM;
+    }
+
+    /* Only NXM supports matching registers. */
+    if (!regs_fully_wildcarded(wc)) {
+        return NXFF_NXM;
+    }
+
+    /* Only NXM supports matching tun_id. */
+    if (wc->tun_id_mask != htonll(0)) {
+        return NXFF_NXM;
+    }
+
+    /* Other formats can express this rule. */
+    return NXFF_OPENFLOW10;
+}
+
+/* Returns an OpenFlow message that can be used to set the flow format to
+ * 'flow_format'.  */
+struct ofpbuf *
+ofputil_make_set_flow_format(enum nx_flow_format flow_format)
+{
+    struct nxt_set_flow_format *sff;
+    struct ofpbuf *msg;
+
+    sff = make_nxmsg(sizeof *sff, NXT_SET_FLOW_FORMAT, &msg);
+    sff->format = htonl(flow_format);
+
+    return msg;
+}
+
+/* Returns an OpenFlow message that can be used to turn the flow_mod_table_id
+ * extension on or off (according to 'flow_mod_table_id'). */
+struct ofpbuf *
+ofputil_make_flow_mod_table_id(bool flow_mod_table_id)
+{
+    struct nxt_flow_mod_table_id *nfmti;
+    struct ofpbuf *msg;
+
+    nfmti = make_nxmsg(sizeof *nfmti, NXT_FLOW_MOD_TABLE_ID, &msg);
+    nfmti->set = flow_mod_table_id;
+    return msg;
+}
+
+/* Converts an OFPT_FLOW_MOD or NXT_FLOW_MOD message 'oh' into an abstract
+ * flow_mod in 'fm'.  Returns 0 if successful, otherwise an OpenFlow error
+ * code.
+ *
+ * 'flow_mod_table_id' should be true if the NXT_FLOW_MOD_TABLE_ID extension is
+ * enabled, false otherwise.
+ *
+ * Does not validate the flow_mod actions. */
+int
+ofputil_decode_flow_mod(struct flow_mod *fm, const struct ofp_header *oh,
+                        bool flow_mod_table_id)
+{
+    const struct ofputil_msg_type *type;
+    uint16_t command;
+    struct ofpbuf b;
+
+    ofpbuf_use_const(&b, oh, ntohs(oh->length));
+
+    ofputil_decode_msg_type(oh, &type);
+    if (ofputil_msg_type_code(type) == OFPUTIL_OFPT_FLOW_MOD) {
+        /* Standard OpenFlow flow_mod. */
+        struct ofp_match match, orig_match;
+        const struct ofp_flow_mod *ofm;
+        int error;
+
+        /* Dissect the message. */
+        ofm = ofpbuf_pull(&b, sizeof *ofm);
+        error = ofputil_pull_actions(&b, b.size, &fm->actions, &fm->n_actions);
+        if (error) {
+            return error;
+        }
+
+        /* Normalize ofm->match.  If normalization actually changes anything,
+         * then log the differences. */
+        match = ofm->match;
+        match.pad1[0] = match.pad2[0] = 0;
+        orig_match = match;
+        normalize_match(&match);
+        if (memcmp(&match, &orig_match, sizeof orig_match)) {
+            if (!VLOG_DROP_INFO(&bad_ofmsg_rl)) {
+                char *old = ofp_match_to_literal_string(&orig_match);
+                char *new = ofp_match_to_literal_string(&match);
+                VLOG_INFO("normalization changed ofp_match, details:");
+                VLOG_INFO(" pre: %s", old);
+                VLOG_INFO("post: %s", new);
+                free(old);
+                free(new);
+            }
+        }
+
+        /* Translate the message. */
+        ofputil_cls_rule_from_match(&match, ntohs(ofm->priority), &fm->cr);
+        fm->cookie = ofm->cookie;
+        command = ntohs(ofm->command);
+        fm->idle_timeout = ntohs(ofm->idle_timeout);
+        fm->hard_timeout = ntohs(ofm->hard_timeout);
+        fm->buffer_id = ntohl(ofm->buffer_id);
+        fm->out_port = ntohs(ofm->out_port);
+        fm->flags = ntohs(ofm->flags);
+    } else if (ofputil_msg_type_code(type) == OFPUTIL_NXT_FLOW_MOD) {
+        /* Nicira extended flow_mod. */
+        const struct nx_flow_mod *nfm;
+        int error;
+
+        /* Dissect the message. */
+        nfm = ofpbuf_pull(&b, sizeof *nfm);
+        error = nx_pull_match(&b, ntohs(nfm->match_len), ntohs(nfm->priority),
+                              &fm->cr);
+        if (error) {
+            return error;
+        }
+        error = ofputil_pull_actions(&b, b.size, &fm->actions, &fm->n_actions);
+        if (error) {
+            return error;
+        }
+
+        /* Translate the message. */
+        fm->cookie = nfm->cookie;
+        command = ntohs(nfm->command);
+        fm->idle_timeout = ntohs(nfm->idle_timeout);
+        fm->hard_timeout = ntohs(nfm->hard_timeout);
+        fm->buffer_id = ntohl(nfm->buffer_id);
+        fm->out_port = ntohs(nfm->out_port);
+        fm->flags = ntohs(nfm->flags);
+    } else {
+        NOT_REACHED();
+    }
+
+    if (flow_mod_table_id) {
+        fm->command = command & 0xff;
+        fm->table_id = command >> 8;
+    } else {
+        fm->command = command;
+        fm->table_id = 0xff;
+    }
+
+    return 0;
+}
+
+/* Converts 'fm' into an OFPT_FLOW_MOD or NXT_FLOW_MOD message according to
+ * 'flow_format' and returns the message.
+ *
+ * 'flow_mod_table_id' should be true if the NXT_FLOW_MOD_TABLE_ID extension is
+ * enabled, false otherwise. */
+struct ofpbuf *
+ofputil_encode_flow_mod(const struct flow_mod *fm,
+                        enum nx_flow_format flow_format,
+                        bool flow_mod_table_id)
+{
+    size_t actions_len = fm->n_actions * sizeof *fm->actions;
+    struct ofpbuf *msg;
+    uint16_t command;
+
+    command = (flow_mod_table_id
+               ? (fm->command & 0xff) | (fm->table_id << 8)
+               : fm->command);
+
+    if (flow_format == NXFF_OPENFLOW10) {
+        struct ofp_flow_mod *ofm;
+
+        msg = ofpbuf_new(sizeof *ofm + actions_len);
+        ofm = put_openflow(sizeof *ofm, OFPT_FLOW_MOD, msg);
+        ofputil_cls_rule_to_match(&fm->cr, &ofm->match);
+        ofm->command = htons(fm->command);
+        ofm->idle_timeout = htons(fm->idle_timeout);
+        ofm->hard_timeout = htons(fm->hard_timeout);
+        ofm->priority = htons(fm->cr.priority);
+        ofm->buffer_id = htonl(fm->buffer_id);
+        ofm->out_port = htons(fm->out_port);
+        ofm->flags = htons(fm->flags);
+    } else if (flow_format == NXFF_NXM) {
+        struct nx_flow_mod *nfm;
+        int match_len;
+
+        msg = ofpbuf_new(sizeof *nfm + NXM_TYPICAL_LEN + actions_len);
+        put_nxmsg(sizeof *nfm, NXT_FLOW_MOD, msg);
+        match_len = nx_put_match(msg, &fm->cr);
+
+        nfm = msg->data;
+        nfm->cookie = fm->cookie;
+        nfm->command = htons(command);
+        nfm->idle_timeout = htons(fm->idle_timeout);
+        nfm->hard_timeout = htons(fm->hard_timeout);
+        nfm->priority = htons(fm->cr.priority);
+        nfm->buffer_id = htonl(fm->buffer_id);
+        nfm->out_port = htons(fm->out_port);
+        nfm->flags = htons(fm->flags);
+        nfm->match_len = htons(match_len);
+    } else {
+        NOT_REACHED();
+    }
+
+    ofpbuf_put(msg, fm->actions, actions_len);
+    update_openflow_length(msg);
+    return msg;
+}
+
+static int
+ofputil_decode_ofpst_flow_request(struct flow_stats_request *fsr,
+                                  const struct ofp_header *oh,
+                                  bool aggregate)
+{
+    const struct ofp_flow_stats_request *ofsr = ofputil_stats_body(oh);
+
+    fsr->aggregate = aggregate;
+    ofputil_cls_rule_from_match(&ofsr->match, 0, &fsr->match);
+    fsr->out_port = ntohs(ofsr->out_port);
+    fsr->table_id = ofsr->table_id;
+
+    return 0;
+}
+
+static int
+ofputil_decode_nxst_flow_request(struct flow_stats_request *fsr,
+                                 const struct ofp_header *oh,
+                                 bool aggregate)
+{
+    const struct nx_flow_stats_request *nfsr;
+    struct ofpbuf b;
+    int error;
+
+    ofpbuf_use_const(&b, oh, ntohs(oh->length));
+
+    nfsr = ofpbuf_pull(&b, sizeof *nfsr);
+    error = nx_pull_match(&b, ntohs(nfsr->match_len), 0, &fsr->match);
+    if (error) {
+        return error;
+    }
+    if (b.size) {
+        return ofp_mkerr(OFPET_BAD_REQUEST, OFPBRC_BAD_LEN);
+    }
+
+    fsr->aggregate = aggregate;
+    fsr->out_port = ntohs(nfsr->out_port);
+    fsr->table_id = nfsr->table_id;
+
+    return 0;
+}
+
+/* Converts an OFPST_FLOW, OFPST_AGGREGATE, NXST_FLOW, or NXST_AGGREGATE
+ * request 'oh', into an abstract flow_stats_request in 'fsr'.  Returns 0 if
+ * successful, otherwise an OpenFlow error code. */
+int
+ofputil_decode_flow_stats_request(struct flow_stats_request *fsr,
+                                  const struct ofp_header *oh)
+{
+    const struct ofputil_msg_type *type;
+    struct ofpbuf b;
+    int code;
+
+    ofpbuf_use_const(&b, oh, ntohs(oh->length));
+
+    ofputil_decode_msg_type(oh, &type);
+    code = ofputil_msg_type_code(type);
+    switch (code) {
+    case OFPUTIL_OFPST_FLOW_REQUEST:
+        return ofputil_decode_ofpst_flow_request(fsr, oh, false);
+
+    case OFPUTIL_OFPST_AGGREGATE_REQUEST:
+        return ofputil_decode_ofpst_flow_request(fsr, oh, true);
+
+    case OFPUTIL_NXST_FLOW_REQUEST:
+        return ofputil_decode_nxst_flow_request(fsr, oh, false);
+
+    case OFPUTIL_NXST_AGGREGATE_REQUEST:
+        return ofputil_decode_nxst_flow_request(fsr, oh, true);
+
+    default:
+        /* Hey, the caller lied. */
+        NOT_REACHED();
+    }
+}
+
+/* Converts abstract flow_stats_request 'fsr' into an OFPST_FLOW,
+ * OFPST_AGGREGATE, NXST_FLOW, or NXST_AGGREGATE request 'oh' according to
+ * 'flow_format', and returns the message. */
+struct ofpbuf *
+ofputil_encode_flow_stats_request(const struct flow_stats_request *fsr,
+                                  enum nx_flow_format flow_format)
+{
+    struct ofpbuf *msg;
+
+    if (flow_format == NXFF_OPENFLOW10) {
+        struct ofp_flow_stats_request *ofsr;
+        int type;
+
+        BUILD_ASSERT_DECL(sizeof(struct ofp_flow_stats_request)
+                          == sizeof(struct ofp_aggregate_stats_request));
+
+        type = fsr->aggregate ? OFPST_AGGREGATE : OFPST_FLOW;
+        ofsr = ofputil_make_stats_request(sizeof *ofsr, type, &msg);
+        ofputil_cls_rule_to_match(&fsr->match, &ofsr->match);
+        ofsr->table_id = fsr->table_id;
+        ofsr->out_port = htons(fsr->out_port);
+    } else if (flow_format == NXFF_NXM) {
+        struct nx_flow_stats_request *nfsr;
+        int match_len;
+        int subtype;
+
+        subtype = fsr->aggregate ? NXST_AGGREGATE : NXST_FLOW;
+        ofputil_make_nxstats_request(sizeof *nfsr, subtype, &msg);
+        match_len = nx_put_match(msg, &fsr->match);
+
+        nfsr = msg->data;
+        nfsr->out_port = htons(fsr->out_port);
+        nfsr->match_len = htons(match_len);
+        nfsr->table_id = fsr->table_id;
+    } else {
+        NOT_REACHED();
+    }
+
+    return msg;
+}
+
+/* Converts an OFPST_FLOW or NXST_FLOW reply in 'msg' into an abstract
+ * ofputil_flow_stats in 'fs'.
+ *
+ * Multiple OFPST_FLOW or NXST_FLOW replies can be packed into a single
+ * OpenFlow message.  Calling this function multiple times for a single 'msg'
+ * iterates through the replies.  The caller must initially leave 'msg''s layer
+ * pointers null and not modify them between calls.
+ *
+ * Returns 0 if successful, EOF if no replies were left in this 'msg',
+ * otherwise a positive errno value. */
+int
+ofputil_decode_flow_stats_reply(struct ofputil_flow_stats *fs,
+                                struct ofpbuf *msg)
+{
+    const struct ofputil_msg_type *type;
+    int code;
+
+    ofputil_decode_msg_type(msg->l2 ? msg->l2 : msg->data, &type);
+    code = ofputil_msg_type_code(type);
+    if (!msg->l2) {
+        msg->l2 = msg->data;
+        if (code == OFPUTIL_OFPST_FLOW_REPLY) {
+            ofpbuf_pull(msg, sizeof(struct ofp_stats_reply));
+        } else if (code == OFPUTIL_NXST_FLOW_REPLY) {
+            ofpbuf_pull(msg, sizeof(struct nicira_stats_msg));
+        } else {
+            NOT_REACHED();
+        }
+    }
+
+    if (!msg->size) {
+        return EOF;
+    } else if (code == OFPUTIL_OFPST_FLOW_REPLY) {
+        const struct ofp_flow_stats *ofs;
+        size_t length;
+
+        ofs = ofpbuf_try_pull(msg, sizeof *ofs);
+        if (!ofs) {
+            VLOG_WARN_RL(&bad_ofmsg_rl, "OFPST_FLOW reply has %zu leftover "
+                         "bytes at end", msg->size);
+            return EINVAL;
+        }
+
+        length = ntohs(ofs->length);
+        if (length < sizeof *ofs) {
+            VLOG_WARN_RL(&bad_ofmsg_rl, "OFPST_FLOW reply claims invalid "
+                         "length %zu", length);
+            return EINVAL;
+        }
+
+        if (ofputil_pull_actions(msg, length - sizeof *ofs,
+                                 &fs->actions, &fs->n_actions)) {
+            return EINVAL;
+        }
+
+        fs->cookie = get_32aligned_be64(&ofs->cookie);
+        ofputil_cls_rule_from_match(&ofs->match, ntohs(ofs->priority),
+                                    &fs->rule);
+        fs->table_id = ofs->table_id;
+        fs->duration_sec = ntohl(ofs->duration_sec);
+        fs->duration_nsec = ntohl(ofs->duration_nsec);
+        fs->idle_timeout = ntohs(ofs->idle_timeout);
+        fs->hard_timeout = ntohs(ofs->hard_timeout);
+        fs->packet_count = ntohll(get_32aligned_be64(&ofs->packet_count));
+        fs->byte_count = ntohll(get_32aligned_be64(&ofs->byte_count));
+    } else if (code == OFPUTIL_NXST_FLOW_REPLY) {
+        const struct nx_flow_stats *nfs;
+        size_t match_len, length;
+
+        nfs = ofpbuf_try_pull(msg, sizeof *nfs);
+        if (!nfs) {
+            VLOG_WARN_RL(&bad_ofmsg_rl, "NXST_FLOW reply has %zu leftover "
+                         "bytes at end", msg->size);
+            return EINVAL;
+        }
+
+        length = ntohs(nfs->length);
+        match_len = ntohs(nfs->match_len);
+        if (length < sizeof *nfs + ROUND_UP(match_len, 8)) {
+            VLOG_WARN_RL(&bad_ofmsg_rl, "NXST_FLOW reply with match_len=%zu "
+                         "claims invalid length %zu", match_len, length);
+            return EINVAL;
+        }
+        if (nx_pull_match(msg, match_len, ntohs(nfs->priority), &fs->rule)) {
+            return EINVAL;
+        }
+
+        if (ofputil_pull_actions(msg,
+                                 length - sizeof *nfs - ROUND_UP(match_len, 8),
+                                 &fs->actions, &fs->n_actions)) {
+            return EINVAL;
+        }
+
+        fs->cookie = nfs->cookie;
+        fs->table_id = nfs->table_id;
+        fs->duration_sec = ntohl(nfs->duration_sec);
+        fs->duration_nsec = ntohl(nfs->duration_nsec);
+        fs->idle_timeout = ntohs(nfs->idle_timeout);
+        fs->hard_timeout = ntohs(nfs->hard_timeout);
+        fs->packet_count = ntohll(nfs->packet_count);
+        fs->byte_count = ntohll(nfs->byte_count);
+    } else {
+        NOT_REACHED();
+    }
+
+    return 0;
+}
+
+/* Converts an OFPT_FLOW_REMOVED or NXT_FLOW_REMOVED message 'oh' into an
+ * abstract ofputil_flow_removed in 'fr'.  Returns 0 if successful, otherwise
+ * an OpenFlow error code. */
+int
+ofputil_decode_flow_removed(struct ofputil_flow_removed *fr,
+                            const struct ofp_header *oh)
+{
+    const struct ofputil_msg_type *type;
+    enum ofputil_msg_code code;
+
+    ofputil_decode_msg_type(oh, &type);
+    code = ofputil_msg_type_code(type);
+    if (code == OFPUTIL_OFPT_FLOW_REMOVED) {
+        const struct ofp_flow_removed *ofr;
+
+        ofr = (const struct ofp_flow_removed *) oh;
+        ofputil_cls_rule_from_match(&ofr->match, ntohs(ofr->priority),
+                                    &fr->rule);
+        fr->cookie = ofr->cookie;
+        fr->reason = ofr->reason;
+        fr->duration_sec = ntohl(ofr->duration_sec);
+        fr->duration_nsec = ntohl(ofr->duration_nsec);
+        fr->idle_timeout = ntohs(ofr->idle_timeout);
+        fr->packet_count = ntohll(ofr->packet_count);
+        fr->byte_count = ntohll(ofr->byte_count);
+    } else if (code == OFPUTIL_NXT_FLOW_REMOVED) {
+        struct nx_flow_removed *nfr;
+        struct ofpbuf b;
+        int error;
+
+        ofpbuf_use_const(&b, oh, ntohs(oh->length));
+
+        nfr = ofpbuf_pull(&b, sizeof *nfr);
+        error = nx_pull_match(&b, ntohs(nfr->match_len), ntohs(nfr->priority),
+                              &fr->rule);
+        if (error) {
+            return error;
+        }
+        if (b.size) {
+            return ofp_mkerr(OFPET_BAD_REQUEST, OFPBRC_BAD_LEN);
+        }
+
+        fr->cookie = nfr->cookie;
+        fr->reason = nfr->reason;
+        fr->duration_sec = ntohl(nfr->duration_sec);
+        fr->duration_nsec = ntohl(nfr->duration_nsec);
+        fr->idle_timeout = ntohs(nfr->idle_timeout);
+        fr->packet_count = ntohll(nfr->packet_count);
+        fr->byte_count = ntohll(nfr->byte_count);
+    } else {
+        NOT_REACHED();
+    }
+
+    return 0;
+}
+
+/* Converts abstract ofputil_flow_removed 'fr' into an OFPT_FLOW_REMOVED or
+ * NXT_FLOW_REMOVED message 'oh' according to 'flow_format', and returns the
+ * message. */
+struct ofpbuf *
+ofputil_encode_flow_removed(const struct ofputil_flow_removed *fr,
+                            enum nx_flow_format flow_format)
+{
+    struct ofpbuf *msg;
+
+    if (flow_format == NXFF_OPENFLOW10) {
+        struct ofp_flow_removed *ofr;
+
+        ofr = make_openflow_xid(sizeof *ofr, OFPT_FLOW_REMOVED, htonl(0),
+                                &msg);
+        ofputil_cls_rule_to_match(&fr->rule, &ofr->match);
+        ofr->priority = htons(fr->rule.priority);
+        ofr->reason = fr->reason;
+        ofr->duration_sec = htonl(fr->duration_sec);
+        ofr->duration_nsec = htonl(fr->duration_nsec);
+        ofr->idle_timeout = htons(fr->idle_timeout);
+        ofr->packet_count = htonll(fr->packet_count);
+        ofr->byte_count = htonll(fr->byte_count);
+    } else if (flow_format == NXFF_NXM) {
+        struct nx_flow_removed *nfr;
+        int match_len;
+
+        make_nxmsg_xid(sizeof *nfr, NXT_FLOW_REMOVED, htonl(0), &msg);
+        match_len = nx_put_match(msg, &fr->rule);
+
+        nfr = msg->data;
+        nfr->cookie = fr->cookie;
+        nfr->priority = htons(fr->rule.priority);
+        nfr->reason = fr->reason;
+        nfr->duration_sec = htonl(fr->duration_sec);
+        nfr->duration_nsec = htonl(fr->duration_nsec);
+        nfr->idle_timeout = htons(fr->idle_timeout);
+        nfr->match_len = htons(match_len);
+        nfr->packet_count = htonll(fr->packet_count);
+        nfr->byte_count = htonll(fr->byte_count);
+    } else {
+        NOT_REACHED();
+    }
+
+    return msg;
+}
 
+/* Converts abstract ofputil_packet_in 'pin' into an OFPT_PACKET_IN message
+ * and returns the message.
+ *
+ * If 'rw_packet' is NULL, the caller takes ownership of the newly allocated
+ * returned ofpbuf.
+ *
+ * If 'rw_packet' is nonnull, then it must contain the same data as
+ * pin->packet.  'rw_packet' is allowed to be the same ofpbuf as pin->packet.
+ * It is modified in-place into an OFPT_PACKET_IN message according to 'pin',
+ * and then ofputil_encode_packet_in() returns 'rw_packet'.  If 'rw_packet' has
+ * enough headroom to insert a "struct ofp_packet_in", this is more efficient
+ * than ofputil_encode_packet_in() because it does not copy the packet
+ * payload. */
+struct ofpbuf *
+ofputil_encode_packet_in(const struct ofputil_packet_in *pin,
+                        struct ofpbuf *rw_packet)
+{
+    int total_len = pin->packet->size;
+    struct ofp_packet_in *opi;
+
+    if (rw_packet) {
+        if (pin->send_len < rw_packet->size) {
+            rw_packet->size = pin->send_len;
+        }
+    } else {
+        rw_packet = ofpbuf_clone_data_with_headroom(
+            pin->packet->data, MIN(pin->send_len, pin->packet->size),
+            offsetof(struct ofp_packet_in, data));
+    }
+
+    /* Add OFPT_PACKET_IN. */
+    opi = ofpbuf_push_zeros(rw_packet, offsetof(struct ofp_packet_in, data));
+    opi->header.version = OFP_VERSION;
+    opi->header.type = OFPT_PACKET_IN;
+    opi->total_len = htons(total_len);
+    opi->in_port = htons(pin->in_port);
+    opi->reason = pin->reason;
+    opi->buffer_id = htonl(pin->buffer_id);
+    update_openflow_length(rw_packet);
+
+    return rw_packet;
+}
+
+/* Returns a string representing the message type of 'type'.  The string is the
+ * enumeration constant for the type, e.g. "OFPT_HELLO".  For statistics
+ * messages, the constant is followed by "request" or "reply",
+ * e.g. "OFPST_AGGREGATE reply". */
+const char *
+ofputil_msg_type_name(const struct ofputil_msg_type *type)
+{
+    return type->name;
+}
+\f
 /* Allocates and stores in '*bufferp' a new ofpbuf with a size of
  * 'openflow_len', starting with an OpenFlow header with the given 'type' and
  * an arbitrary transaction id.  Allocated bytes beyond the header, if any, are
@@ -326,11 +1473,8 @@ void *
 make_nxmsg_xid(size_t openflow_len, uint32_t subtype, ovs_be32 xid,
                struct ofpbuf **bufferp)
 {
-    struct nicira_header *nxh = make_openflow_xid(openflow_len, OFPT_VENDOR,
-                                                  xid, bufferp);
-    nxh->vendor = htonl(NX_VENDOR_ID);
-    nxh->subtype = htonl(subtype);
-    return nxh;
+    *bufferp = ofpbuf_new(openflow_len);
+    return put_nxmsg_xid(openflow_len, subtype, xid, *bufferp);
 }
 
 /* Appends 'openflow_len' bytes to 'buffer', starting with an OpenFlow header
@@ -375,6 +1519,28 @@ put_openflow_xid(size_t openflow_len, uint8_t type, ovs_be32 xid,
     return oh;
 }
 
+/* Similar to put_openflow() but append a Nicira vendor extension message with
+ * the specific 'subtype'.  'subtype' should be in host byte order. */
+void *
+put_nxmsg(size_t openflow_len, uint32_t subtype, struct ofpbuf *buffer)
+{
+    return put_nxmsg_xid(openflow_len, subtype, alloc_xid(), buffer);
+}
+
+/* Similar to put_openflow_xid() but append a Nicira vendor extension message
+ * with the specific 'subtype'.  'subtype' should be in host byte order. */
+void *
+put_nxmsg_xid(size_t openflow_len, uint32_t subtype, ovs_be32 xid,
+              struct ofpbuf *buffer)
+{
+    struct nicira_header *nxh;
+
+    nxh = put_openflow_xid(openflow_len, OFPT_VENDOR, xid, buffer);
+    nxh->vendor = htonl(NX_VENDOR_ID);
+    nxh->subtype = htonl(subtype);
+    return nxh;
+}
+
 /* Updates the 'length' field of the OpenFlow message in 'buffer' to
  * 'buffer->size'. */
 void
@@ -384,6 +1550,71 @@ update_openflow_length(struct ofpbuf *buffer)
     oh->length = htons(buffer->size);
 }
 
+/* Creates an ofp_stats_request with the given 'type' and 'body_len' bytes of
+ * space allocated for the 'body' member.  Returns the first byte of the 'body'
+ * member. */
+void *
+ofputil_make_stats_request(size_t body_len, uint16_t type,
+                           struct ofpbuf **bufferp)
+{
+    struct ofp_stats_request *osr;
+    osr = make_openflow((offsetof(struct ofp_stats_request, body)
+                        + body_len), OFPT_STATS_REQUEST, bufferp);
+    osr->type = htons(type);
+    osr->flags = htons(0);
+    return osr->body;
+}
+
+/* Creates a stats request message with Nicira as vendor and the given
+ * 'subtype', of total length 'openflow_len'.  Returns the message. */
+void *
+ofputil_make_nxstats_request(size_t openflow_len, uint32_t subtype,
+                             struct ofpbuf **bufferp)
+{
+    struct nicira_stats_msg *nsm;
+
+    nsm = make_openflow(openflow_len, OFPT_STATS_REQUEST, bufferp);
+    nsm->type = htons(OFPST_VENDOR);
+    nsm->flags = htons(0);
+    nsm->vendor = htonl(NX_VENDOR_ID);
+    nsm->subtype = htonl(subtype);
+    return nsm;
+}
+
+/* Returns the first byte of the 'body' member of the ofp_stats_request or
+ * ofp_stats_reply in 'oh'. */
+const void *
+ofputil_stats_body(const struct ofp_header *oh)
+{
+    assert(oh->type == OFPT_STATS_REQUEST || oh->type == OFPT_STATS_REPLY);
+    return ((const struct ofp_stats_request *) oh)->body;
+}
+
+/* Returns the length of the 'body' member of the ofp_stats_request or
+ * ofp_stats_reply in 'oh'. */
+size_t
+ofputil_stats_body_len(const struct ofp_header *oh)
+{
+    assert(oh->type == OFPT_STATS_REQUEST || oh->type == OFPT_STATS_REPLY);
+    return ntohs(oh->length) - sizeof(struct ofp_stats_request);
+}
+
+/* Returns the first byte of the body of the nicira_stats_msg in 'oh'. */
+const void *
+ofputil_nxstats_body(const struct ofp_header *oh)
+{
+    assert(oh->type == OFPT_STATS_REQUEST || oh->type == OFPT_STATS_REPLY);
+    return ((const struct nicira_stats_msg *) oh) + 1;
+}
+
+/* Returns the length of the body of the nicira_stats_msg in 'oh'. */
+size_t
+ofputil_nxstats_body_len(const struct ofp_header *oh)
+{
+    assert(oh->type == OFPT_STATS_REQUEST || oh->type == OFPT_STATS_REPLY);
+    return ntohs(oh->length) - sizeof(struct nicira_stats_msg);
+}
+
 struct ofpbuf *
 make_flow_mod(uint16_t command, const struct cls_rule *rule,
               size_t actions_len)
@@ -397,7 +1628,7 @@ make_flow_mod(uint16_t command, const struct cls_rule *rule,
     ofm->header.length = htons(size);
     ofm->cookie = 0;
     ofm->priority = htons(MIN(rule->priority, UINT16_MAX));
-    ofputil_cls_rule_to_match(rule, NXFF_OPENFLOW10, &ofm->match);
+    ofputil_cls_rule_to_match(rule, &ofm->match);
     ofm->command = htons(command);
     return out;
 }
@@ -545,150 +1776,27 @@ make_echo_reply(const struct ofp_header *rq)
 }
 
 static int
-check_message_type(uint8_t got_type, uint8_t want_type)
-{
-    if (got_type != want_type) {
-        char *want_type_name = ofp_message_type_to_string(want_type);
-        char *got_type_name = ofp_message_type_to_string(got_type);
-        VLOG_WARN_RL(&bad_ofmsg_rl,
-                     "received bad message type %s (expected %s)",
-                     got_type_name, want_type_name);
-        free(want_type_name);
-        free(got_type_name);
-        return ofp_mkerr(OFPET_BAD_REQUEST, OFPBRC_BAD_TYPE);
-    }
-    return 0;
-}
-
-/* Checks that 'msg' has type 'type' and that it is exactly 'size' bytes long.
- * Returns 0 if the checks pass, otherwise an OpenFlow error code (produced
- * with ofp_mkerr()). */
-int
-check_ofp_message(const struct ofp_header *msg, uint8_t type, size_t size)
-{
-    size_t got_size;
-    int error;
-
-    error = check_message_type(msg->type, type);
-    if (error) {
-        return error;
-    }
-
-    got_size = ntohs(msg->length);
-    if (got_size != size) {
-        char *type_name = ofp_message_type_to_string(type);
-        VLOG_WARN_RL(&bad_ofmsg_rl,
-                     "received %s message of length %zu (expected %zu)",
-                     type_name, got_size, size);
-        free(type_name);
-        return ofp_mkerr(OFPET_BAD_REQUEST, OFPBRC_BAD_LEN);
-    }
-
-    return 0;
-}
-
-/* Checks that 'msg' has type 'type' and that 'msg' is 'size' plus a
- * nonnegative integer multiple of 'array_elt_size' bytes long.  Returns 0 if
- * the checks pass, otherwise an OpenFlow error code (produced with
- * ofp_mkerr()).
- *
- * If 'n_array_elts' is nonnull, then '*n_array_elts' is set to the number of
- * 'array_elt_size' blocks in 'msg' past the first 'min_size' bytes, when
- * successful. */
-int
-check_ofp_message_array(const struct ofp_header *msg, uint8_t type,
-                        size_t min_size, size_t array_elt_size,
-                        size_t *n_array_elts)
+check_action_exact_len(const union ofp_action *a, unsigned int len,
+                       unsigned int required_len)
 {
-    size_t got_size;
-    int error;
-
-    assert(array_elt_size);
-
-    error = check_message_type(msg->type, type);
-    if (error) {
-        return error;
-    }
-
-    got_size = ntohs(msg->length);
-    if (got_size < min_size) {
-        char *type_name = ofp_message_type_to_string(type);
-        VLOG_WARN_RL(&bad_ofmsg_rl, "received %s message of length %zu "
-                     "(expected at least %zu)",
-                     type_name, got_size, min_size);
-        free(type_name);
-        return ofp_mkerr(OFPET_BAD_REQUEST, OFPBRC_BAD_LEN);
-    }
-    if ((got_size - min_size) % array_elt_size) {
-        char *type_name = ofp_message_type_to_string(type);
-        VLOG_WARN_RL(&bad_ofmsg_rl,
-                     "received %s message of bad length %zu: the "
-                     "excess over %zu (%zu) is not evenly divisible by %zu "
-                     "(remainder is %zu)",
-                     type_name, got_size, min_size, got_size - min_size,
-                     array_elt_size, (got_size - min_size) % array_elt_size);
-        free(type_name);
-        return ofp_mkerr(OFPET_BAD_REQUEST, OFPBRC_BAD_LEN);
-    }
-    if (n_array_elts) {
-        *n_array_elts = (got_size - min_size) / array_elt_size;
+    if (len != required_len) {
+        VLOG_WARN_RL(&bad_ofmsg_rl, "action %"PRIu16" has invalid length "
+                     "%"PRIu16" (must be %u)\n",
+                     ntohs(a->type), ntohs(a->header.len), required_len);
+        return ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_LEN);
     }
     return 0;
 }
 
-const struct ofp_flow_stats *
-flow_stats_first(struct flow_stats_iterator *iter,
-                 const struct ofp_stats_reply *osr)
-{
-    iter->pos = osr->body;
-    iter->end = osr->body + (ntohs(osr->header.length)
-                             - offsetof(struct ofp_stats_reply, body));
-    return flow_stats_next(iter);
-}
-
-const struct ofp_flow_stats *
-flow_stats_next(struct flow_stats_iterator *iter)
-{
-    ptrdiff_t bytes_left = iter->end - iter->pos;
-    const struct ofp_flow_stats *fs;
-    size_t length;
-
-    if (bytes_left < sizeof *fs) {
-        if (bytes_left != 0) {
-            VLOG_WARN_RL(&bad_ofmsg_rl,
-                         "%td leftover bytes in flow stats reply", bytes_left);
-        }
-        return NULL;
-    }
-
-    fs = (const void *) iter->pos;
-    length = ntohs(fs->length);
-    if (length < sizeof *fs) {
-        VLOG_WARN_RL(&bad_ofmsg_rl, "flow stats length %zu is shorter than "
-                     "min %zu", length, sizeof *fs);
-        return NULL;
-    } else if (length > bytes_left) {
-        VLOG_WARN_RL(&bad_ofmsg_rl, "flow stats length %zu but only %td "
-                     "bytes left", length, bytes_left);
-        return NULL;
-    } else if ((length - sizeof *fs) % sizeof fs->actions[0]) {
-        VLOG_WARN_RL(&bad_ofmsg_rl, "flow stats length %zu has %zu bytes "
-                     "left over in final action", length,
-                     (length - sizeof *fs) % sizeof fs->actions[0]);
-        return NULL;
-    }
-    iter->pos += length;
-    return fs;
-}
-
 static int
-check_action_exact_len(const union ofp_action *a, unsigned int len,
-                       unsigned int required_len)
+check_nx_action_exact_len(const struct nx_action_header *a,
+                          unsigned int len, unsigned int required_len)
 {
     if (len != required_len) {
-        VLOG_DBG_RL(&bad_ofmsg_rl,
-                    "action %u has invalid length %"PRIu16" (must be %u)\n",
-                    a->type, ntohs(a->header.len), required_len);
+        VLOG_WARN_RL(&bad_ofmsg_rl,
+                     "Nicira action %"PRIu16" has invalid length %"PRIu16" "
+                     "(must be %u)\n",
+                     ntohs(a->subtype), ntohs(a->len), required_len);
         return ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_LEN);
     }
     return 0;
@@ -749,34 +1857,42 @@ check_nicira_action(const union ofp_action *a, unsigned int len,
                     const struct flow *flow)
 {
     const struct nx_action_header *nah;
+    int subtype;
     int error;
 
     if (len < 16) {
-        VLOG_DBG_RL(&bad_ofmsg_rl,
-                    "Nicira vendor action only %u bytes", len);
+        VLOG_WARN_RL(&bad_ofmsg_rl,
+                     "Nicira vendor action only %u bytes", len);
         return ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_LEN);
     }
     nah = (const struct nx_action_header *) a;
 
-    switch (ntohs(nah->subtype)) {
+    subtype = ntohs(nah->subtype);
+    if (subtype > TYPE_MAXIMUM(enum nx_action_subtype)) {
+        /* This is necessary because enum nx_action_subtype may be an
+         * 8-bit type, so the cast below throws away the top 8 bits. */
+        return ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_VENDOR_TYPE);
+    }
+
+    switch ((enum nx_action_subtype) subtype) {
     case NXAST_RESUBMIT:
     case NXAST_SET_TUNNEL:
     case NXAST_DROP_SPOOFED_ARP:
     case NXAST_SET_QUEUE:
     case NXAST_POP_QUEUE:
-        return check_action_exact_len(a, len, 16);
+        return check_nx_action_exact_len(nah, len, 16);
 
     case NXAST_REG_MOVE:
-        error = check_action_exact_len(a, len,
-                                       sizeof(struct nx_action_reg_move));
+        error = check_nx_action_exact_len(nah, len,
+                                          sizeof(struct nx_action_reg_move));
         if (error) {
             return error;
         }
         return nxm_check_reg_move((const struct nx_action_reg_move *) a, flow);
 
     case NXAST_REG_LOAD:
-        error = check_action_exact_len(a, len,
-                                       sizeof(struct nx_action_reg_load));
+        error = check_nx_action_exact_len(nah, len,
+                                          sizeof(struct nx_action_reg_load));
         if (error) {
             return error;
         }
@@ -785,7 +1901,30 @@ check_nicira_action(const union ofp_action *a, unsigned int len,
     case NXAST_NOTE:
         return 0;
 
+    case NXAST_SET_TUNNEL64:
+        return check_nx_action_exact_len(
+            nah, len, sizeof(struct nx_action_set_tunnel64));
+
+    case NXAST_MULTIPATH:
+        error = check_nx_action_exact_len(
+            nah, len, sizeof(struct nx_action_multipath));
+        if (error) {
+            return error;
+        }
+        return multipath_check((const struct nx_action_multipath *) a);
+
+    case NXAST_AUTOPATH:
+        error = check_nx_action_exact_len(
+            nah, len, sizeof(struct nx_action_autopath));
+        if (error) {
+            return error;
+        }
+        return autopath_check((const struct nx_action_autopath *) a);
+
+    case NXAST_SNAT__OBSOLETE:
     default:
+        VLOG_WARN_RL(&bad_ofmsg_rl,
+                     "unknown Nicira vendor action subtype %d", subtype);
         return ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_VENDOR_TYPE);
     }
 }
@@ -794,9 +1933,10 @@ static int
 check_action(const union ofp_action *a, unsigned int len,
              const struct flow *flow, int max_ports)
 {
+    enum ofp_action_type type = ntohs(a->type);
     int error;
 
-    switch (ntohs(a->type)) {
+    switch (type) {
     case OFPAT_OUTPUT:
         error = check_action_exact_len(a, len, 8);
         if (error) {
@@ -819,7 +1959,7 @@ check_action(const union ofp_action *a, unsigned int len,
         if (error) {
             return error;
         }
-        if (a->vlan_vid.vlan_vid & ~7) {
+        if (a->vlan_pcp.vlan_pcp & ~7) {
             return ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_ARGUMENT);
         }
         return 0;
@@ -845,8 +1985,7 @@ check_action(const union ofp_action *a, unsigned int len,
         return check_enqueue_action(a, len, max_ports);
 
     default:
-        VLOG_WARN_RL(&bad_ofmsg_rl, "unknown action type %"PRIu16,
-                ntohs(a->type));
+        VLOG_WARN_RL(&bad_ofmsg_rl, "unknown action type %d", (int) type);
         return ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_TYPE);
     }
 }
@@ -865,16 +2004,16 @@ validate_actions(const union ofp_action *actions, size_t n_actions,
         int error;
 
         if (n_slots > slots_left) {
-            VLOG_DBG_RL(&bad_ofmsg_rl,
-                        "action requires %u slots but only %u remain",
-                        n_slots, slots_left);
+            VLOG_WARN_RL(&bad_ofmsg_rl,
+                         "action requires %u slots but only %u remain",
+                         n_slots, slots_left);
             return ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_LEN);
         } else if (!len) {
-            VLOG_DBG_RL(&bad_ofmsg_rl, "action has invalid length 0");
+            VLOG_WARN_RL(&bad_ofmsg_rl, "action has invalid length 0");
             return ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_LEN);
         } else if (len % OFP_ACTION_ALIGN) {
-            VLOG_DBG_RL(&bad_ofmsg_rl, "action length %u is not a multiple "
-                        "of %d", len, OFP_ACTION_ALIGN);
+            VLOG_WARN_RL(&bad_ofmsg_rl, "action length %u is not a multiple "
+                         "of %d", len, OFP_ACTION_ALIGN);
             return ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_LEN);
         }
 
@@ -887,10 +2026,9 @@ validate_actions(const union ofp_action *actions, size_t n_actions,
     return 0;
 }
 
-/* Returns true if 'action' outputs to 'port' (which must be in network byte
- * order), false otherwise. */
+/* Returns true if 'action' outputs to 'port', false otherwise. */
 bool
-action_outputs_to_port(const union ofp_action *action, uint16_t port)
+action_outputs_to_port(const union ofp_action *action, ovs_be16 port)
 {
     switch (ntohs(action->type)) {
     case OFPAT_OUTPUT:
@@ -934,7 +2072,7 @@ normalize_match(struct ofp_match *m)
     enum { OFPFW_TP = OFPFW_TP_SRC | OFPFW_TP_DST };
     uint32_t wc;
 
-    wc = ntohl(m->wildcards) & OVSFW_ALL;
+    wc = ntohl(m->wildcards) & OFPFW_ALL;
     if (wc & OFPFW_DL_TYPE) {
         m->dl_type = 0;
 
@@ -988,6 +2126,9 @@ normalize_match(struct ofp_match *m)
             m->nw_dst &= ofputil_wcbits_to_netmask(wc >> OFPFW_NW_DST_SHIFT);
         }
         m->tp_src = m->tp_dst = m->nw_tos = 0;
+    } else if (m->dl_type == htons(ETH_TYPE_IPV6)) {
+        /* Don't normalize IPv6 traffic, since OpenFlow doesn't have a
+         * way to express it. */
     } else {
         /* Network and transport layer fields will always be extracted as
          * zeros, so we can do an exact-match on those values. */
@@ -1054,6 +2195,18 @@ vendor_code_to_id(uint8_t code)
     }
 }
 
+static int
+vendor_id_to_code(uint32_t id)
+{
+    switch (id) {
+#define OFPUTIL_VENDOR(NAME, VENDOR_ID) case VENDOR_ID: return NAME;
+        OFPUTIL_VENDORS
+#undef OFPUTIL_VENDOR
+    default:
+        return -1;
+    }
+}
+
 /* Creates and returns an OpenFlow message of type OFPT_ERROR with the error
  * information taken from 'error', whose encoding must be as described in the
  * large comment in ofp-util.h.  If 'oh' is nonnull, then the error will use
@@ -1062,7 +2215,7 @@ vendor_code_to_id(uint8_t code)
  *
  * Returns NULL if 'error' is not an OpenFlow error code. */
 struct ofpbuf *
-make_ofp_error_msg(int error, const struct ofp_header *oh)
+ofputil_encode_error_msg(int error, const struct ofp_header *oh)
 {
     static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
 
@@ -1121,19 +2274,116 @@ make_ofp_error_msg(int error, const struct ofp_header *oh)
         oem->type = htons(NXET_VENDOR);
         oem->code = htons(NXVC_VENDOR_ERROR);
 
-        nve = ofpbuf_put_uninit(buf, sizeof *nve);
+        nve = (struct nx_vendor_error *)oem->data;
         nve->vendor = htonl(vendor_id);
         nve->type = htons(type);
         nve->code = htons(code);
     }
 
     if (len) {
+        buf->size -= len;
         ofpbuf_put(buf, data, len);
     }
 
     return buf;
 }
 
+/* Decodes 'oh', which should be an OpenFlow OFPT_ERROR message, and returns an
+ * Open vSwitch internal error code in the format described in the large
+ * comment in ofp-util.h.
+ *
+ * If 'payload_ofs' is nonnull, on success '*payload_ofs' is set to the offset
+ * to the payload starting from 'oh' and on failure it is set to 0. */
+int
+ofputil_decode_error_msg(const struct ofp_header *oh, size_t *payload_ofs)
+{
+    static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
+
+    const struct ofp_error_msg *oem;
+    uint16_t type, code;
+    struct ofpbuf b;
+    int vendor;
+
+    if (payload_ofs) {
+        *payload_ofs = 0;
+    }
+    if (oh->type != OFPT_ERROR) {
+        return EPROTO;
+    }
+
+    ofpbuf_use_const(&b, oh, ntohs(oh->length));
+    oem = ofpbuf_try_pull(&b, sizeof *oem);
+    if (!oem) {
+        return EPROTO;
+    }
+
+    type = ntohs(oem->type);
+    code = ntohs(oem->code);
+    if (type == NXET_VENDOR && code == NXVC_VENDOR_ERROR) {
+        const struct nx_vendor_error *nve = ofpbuf_try_pull(&b, sizeof *nve);
+        if (!nve) {
+            return EPROTO;
+        }
+
+        vendor = vendor_id_to_code(ntohl(nve->vendor));
+        if (vendor < 0) {
+            VLOG_WARN_RL(&rl, "error contains unknown vendor ID %#"PRIx32,
+                         ntohl(nve->vendor));
+            return EPROTO;
+        }
+        type = ntohs(nve->type);
+        code = ntohs(nve->code);
+    } else {
+        vendor = OFPUTIL_VENDOR_OPENFLOW;
+    }
+
+    if (type >= 1024) {
+        VLOG_WARN_RL(&rl, "error contains type %"PRIu16" greater than "
+                     "supported maximum value 1023", type);
+        return EPROTO;
+    }
+
+    if (payload_ofs) {
+        *payload_ofs = (uint8_t *) b.data - (uint8_t *) oh;
+    }
+    return ofp_mkerr_vendor(vendor, type, code);
+}
+
+void
+ofputil_format_error(struct ds *s, int error)
+{
+    if (is_errno(error)) {
+        ds_put_cstr(s, strerror(error));
+    } else {
+        uint16_t type = get_ofp_err_type(error);
+        uint16_t code = get_ofp_err_code(error);
+        const char *type_s = ofp_error_type_to_string(type);
+        const char *code_s = ofp_error_code_to_string(type, code);
+
+        ds_put_format(s, "type ");
+        if (type_s) {
+            ds_put_cstr(s, type_s);
+        } else {
+            ds_put_format(s, "%"PRIu16, type);
+        }
+
+        ds_put_cstr(s, ", code ");
+        if (code_s) {
+            ds_put_cstr(s, code_s);
+        } else {
+            ds_put_format(s, "%"PRIu16, code);
+        }
+    }
+}
+
+char *
+ofputil_error_to_string(int error)
+{
+    struct ds s = DS_EMPTY_INITIALIZER;
+    ofputil_format_error(&s, error);
+    return ds_steal_cstr(&s);
+}
+
 /* Attempts to pull 'actions_len' bytes from the front of 'b'.  Returns 0 if
  * successful, otherwise an OpenFlow error.
  *
@@ -1150,16 +2400,16 @@ ofputil_pull_actions(struct ofpbuf *b, unsigned int actions_len,
                      union ofp_action **actionsp, size_t *n_actionsp)
 {
     if (actions_len % OFP_ACTION_ALIGN != 0) {
-        VLOG_DBG_RL(&bad_ofmsg_rl, "OpenFlow message actions length %u "
-                    "is not a multiple of %d", actions_len, OFP_ACTION_ALIGN);
+        VLOG_WARN_RL(&bad_ofmsg_rl, "OpenFlow message actions length %u "
+                     "is not a multiple of %d", actions_len, OFP_ACTION_ALIGN);
         goto error;
     }
 
     *actionsp = ofpbuf_try_pull(b, actions_len);
     if (*actionsp == NULL) {
-        VLOG_DBG_RL(&bad_ofmsg_rl, "OpenFlow message actions length %u "
-                    "exceeds remaining message length (%zu)",
-                    actions_len, b->size);
+        VLOG_WARN_RL(&bad_ofmsg_rl, "OpenFlow message actions length %u "
+                     "exceeds remaining message length (%zu)",
+                     actions_len, b->size);
         goto error;
     }