/* * Copyright (c) 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include #include "nx-match.h" #include #include "classifier.h" #include "colors.h" #include "openvswitch/hmap.h" #include "openflow/nicira-ext.h" #include "openvswitch/dynamic-string.h" #include "openvswitch/meta-flow.h" #include "openvswitch/ofp-actions.h" #include "openvswitch/ofp-errors.h" #include "openvswitch/ofp-util.h" #include "openvswitch/ofpbuf.h" #include "openvswitch/vlog.h" #include "packets.h" #include "openvswitch/shash.h" #include "tun-metadata.h" #include "unaligned.h" #include "util.h" #include "vl-mff-map.h" VLOG_DEFINE_THIS_MODULE(nx_match); /* OXM headers. * * * Standard OXM/NXM * ================ * * The header is 32 bits long. It looks like this: * * |31 16 15 9| 8 7 0 * +----------------------------------+---------------+--+------------------+ * | oxm_class | oxm_field |hm| oxm_length | * +----------------------------------+---------------+--+------------------+ * * where hm stands for oxm_hasmask. It is followed by oxm_length bytes of * payload. When oxm_hasmask is 0, the payload is the value of the field * identified by the header; when oxm_hasmask is 1, the payload is a value for * the field followed by a mask of equal length. * * Internally, we represent a standard OXM header as a 64-bit integer with the * above information in the most-significant bits. * * * Experimenter OXM * ================ * * The header is 64 bits long. It looks like the diagram above except that a * 32-bit experimenter ID, which we call oxm_vendor and which identifies a * vendor, is inserted just before the payload. Experimenter OXMs are * identified by an all-1-bits oxm_class (OFPXMC12_EXPERIMENTER). The * oxm_length value *includes* the experimenter ID, so that the real payload is * only oxm_length - 4 bytes long. * * Internally, we represent an experimenter OXM header as a 64-bit integer with * the standard header in the upper 32 bits and the experimenter ID in the * lower 32 bits. (It would be more convenient to swap the positions of the * two 32-bit words, but this would be more error-prone because experimenter * OXMs are very rarely used, so accidentally passing one through a 32-bit type * somewhere in the OVS code would be hard to find.) */ /* * OXM Class IDs. * The high order bit differentiate reserved classes from member classes. * Classes 0x0000 to 0x7FFF are member classes, allocated by ONF. * Classes 0x8000 to 0xFFFE are reserved classes, reserved for standardisation. */ enum ofp12_oxm_class { OFPXMC12_NXM_0 = 0x0000, /* Backward compatibility with NXM */ OFPXMC12_NXM_1 = 0x0001, /* Backward compatibility with NXM */ OFPXMC12_OPENFLOW_BASIC = 0x8000, /* Basic class for OpenFlow */ OFPXMC15_PACKET_REGS = 0x8001, /* Packet registers (pipeline fields). */ OFPXMC12_EXPERIMENTER = 0xffff, /* Experimenter class */ }; /* Functions for extracting raw field values from OXM/NXM headers. */ static uint32_t nxm_vendor(uint64_t header) { return header; } static int nxm_class(uint64_t header) { return header >> 48; } static int nxm_field(uint64_t header) { return (header >> 41) & 0x7f; } static bool nxm_hasmask(uint64_t header) { return (header >> 40) & 1; } static int nxm_length(uint64_t header) { return (header >> 32) & 0xff; } static uint64_t nxm_no_len(uint64_t header) { return header & 0xffffff80ffffffffULL; } static bool is_experimenter_oxm(uint64_t header) { return nxm_class(header) == OFPXMC12_EXPERIMENTER; } /* The OXM header "length" field is somewhat tricky: * * - For a standard OXM header, the length is the number of bytes of the * payload, and the payload consists of just the value (and mask, if * present). * * - For an experimenter OXM header, the length is the number of bytes in * the payload plus 4 (the length of the experimenter ID). That is, the * experimenter ID is included in oxm_length. * * This function returns the length of the experimenter ID field in 'header'. * That is, for an experimenter OXM (when an experimenter ID is present), it * returns 4, and for a standard OXM (when no experimenter ID is present), it * returns 0. */ static int nxm_experimenter_len(uint64_t header) { return is_experimenter_oxm(header) ? 4 : 0; } /* Returns the number of bytes that follow the header for an NXM/OXM entry * with the given 'header'. */ static int nxm_payload_len(uint64_t header) { return nxm_length(header) - nxm_experimenter_len(header); } /* Returns the number of bytes in the header for an NXM/OXM entry with the * given 'header'. */ static int nxm_header_len(uint64_t header) { return 4 + nxm_experimenter_len(header); } #define NXM_HEADER(VENDOR, CLASS, FIELD, HASMASK, LENGTH) \ (((uint64_t) (CLASS) << 48) | \ ((uint64_t) (FIELD) << 41) | \ ((uint64_t) (HASMASK) << 40) | \ ((uint64_t) (LENGTH) << 32) | \ (VENDOR)) #define NXM_HEADER_FMT "%#"PRIx32":%d:%d:%d:%d" #define NXM_HEADER_ARGS(HEADER) \ nxm_vendor(HEADER), nxm_class(HEADER), nxm_field(HEADER), \ nxm_hasmask(HEADER), nxm_length(HEADER) /* Functions for turning the "hasmask" bit on or off. (This also requires * adjusting the length.) */ static uint64_t nxm_make_exact_header(uint64_t header) { int new_len = nxm_payload_len(header) / 2 + nxm_experimenter_len(header); return NXM_HEADER(nxm_vendor(header), nxm_class(header), nxm_field(header), 0, new_len); } static uint64_t nxm_make_wild_header(uint64_t header) { int new_len = nxm_payload_len(header) * 2 + nxm_experimenter_len(header); return NXM_HEADER(nxm_vendor(header), nxm_class(header), nxm_field(header), 1, new_len); } /* Flow cookie. * * This may be used to gain the OpenFlow 1.1-like ability to restrict * certain NXM-based Flow Mod and Flow Stats Request messages to flows * with specific cookies. See the "nx_flow_mod" and "nx_flow_stats_request" * structure definitions for more details. This match is otherwise not * allowed. */ #define NXM_NX_COOKIE NXM_HEADER (0, 0x0001, 30, 0, 8) #define NXM_NX_COOKIE_W nxm_make_wild_header(NXM_NX_COOKIE) struct nxm_field { uint64_t header; enum ofp_version version; const char *name; /* e.g. "NXM_OF_IN_PORT". */ enum mf_field_id id; }; static const struct nxm_field *nxm_field_by_header(uint64_t header); static const struct nxm_field *nxm_field_by_name(const char *name, size_t len); static const struct nxm_field *nxm_field_by_mf_id(enum mf_field_id, enum ofp_version); static void nx_put_header__(struct ofpbuf *, uint64_t header, bool masked); static void nx_put_header_len(struct ofpbuf *, enum mf_field_id field, enum ofp_version version, bool masked, size_t n_bytes); /* Rate limit for nx_match parse errors. These always indicate a bug in the * peer and so there's not much point in showing a lot of them. */ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5); static const struct nxm_field * mf_parse_subfield_name(const char *name, int name_len, bool *wild); /* Returns the preferred OXM header to use for field 'id' in OpenFlow version * 'version'. Specify 0 for 'version' if an NXM legacy header should be * preferred over any standardized OXM header. Returns 0 if field 'id' cannot * be expressed in NXM or OXM. */ static uint64_t mf_oxm_header(enum mf_field_id id, enum ofp_version version) { const struct nxm_field *f = nxm_field_by_mf_id(id, version); return f ? f->header : 0; } /* Returns the 32-bit OXM or NXM header to use for field 'id', preferring an * NXM legacy header over any standardized OXM header. Returns 0 if field 'id' * cannot be expressed with a 32-bit NXM or OXM header. * * Whenever possible, use nx_pull_header() instead of this function, because * this function cannot support 64-bit experimenter OXM headers. */ uint32_t mf_nxm_header(enum mf_field_id id) { uint64_t oxm = mf_oxm_header(id, 0); return is_experimenter_oxm(oxm) ? 0 : oxm >> 32; } /* Returns the 32-bit OXM or NXM header to use for field 'mff'. If 'mff' is * a mapped variable length mf_field, update the header with the configured * length of 'mff'. Returns 0 if 'mff' cannot be expressed with a 32-bit NXM * or OXM header.*/ uint32_t nxm_header_from_mff(const struct mf_field *mff) { uint64_t oxm = mf_oxm_header(mff->id, 0); if (mff->mapped) { oxm = nxm_no_len(oxm) | ((uint64_t) mff->n_bytes << 32); } return is_experimenter_oxm(oxm) ? 0 : oxm >> 32; } static const struct mf_field * mf_from_oxm_header(uint64_t header, const struct vl_mff_map *vl_mff_map) { const struct nxm_field *f = nxm_field_by_header(header); if (f) { const struct mf_field *mff = mf_from_id(f->id); const struct mf_field *vl_mff = mf_get_vl_mff(mff, vl_mff_map); return vl_mff ? vl_mff : mff; } else { return NULL; } } /* Returns the "struct mf_field" that corresponds to NXM or OXM header * 'header', or NULL if 'header' doesn't correspond to any known field. */ const struct mf_field * mf_from_nxm_header(uint32_t header, const struct vl_mff_map *vl_mff_map) { return mf_from_oxm_header((uint64_t) header << 32, vl_mff_map); } /* Returns the width of the data for a field with the given 'header', in * bytes. */ static int nxm_field_bytes(uint64_t header) { unsigned int length = nxm_payload_len(header); return nxm_hasmask(header) ? length / 2 : length; } /* nx_pull_match() and helpers. */ /* Given NXM/OXM value 'value' and mask 'mask' associated with 'header', checks * for any 1-bit in the value where there is a 0-bit in the mask. Returns 0 if * none, otherwise an error code. */ static bool is_mask_consistent(uint64_t header, const uint8_t *value, const uint8_t *mask) { unsigned int width = nxm_field_bytes(header); unsigned int i; for (i = 0; i < width; i++) { if (value[i] & ~mask[i]) { if (!VLOG_DROP_WARN(&rl)) { VLOG_WARN_RL(&rl, "Rejecting NXM/OXM entry "NXM_HEADER_FMT " " "with 1-bits in value for bits wildcarded by the " "mask.", NXM_HEADER_ARGS(header)); } return false; } } return true; } static bool is_cookie_pseudoheader(uint64_t header) { return header == NXM_NX_COOKIE || header == NXM_NX_COOKIE_W; } static enum ofperr nx_pull_header__(struct ofpbuf *b, bool allow_cookie, const struct vl_mff_map *vl_mff_map, uint64_t *header, const struct mf_field **field) { if (b->size < 4) { goto bad_len; } *header = ((uint64_t) ntohl(get_unaligned_be32(b->data))) << 32; if (is_experimenter_oxm(*header)) { if (b->size < 8) { goto bad_len; } *header = ntohll(get_unaligned_be64(b->data)); } if (nxm_length(*header) < nxm_experimenter_len(*header)) { VLOG_WARN_RL(&rl, "OXM header "NXM_HEADER_FMT" has invalid length %d " "(minimum is %d)", NXM_HEADER_ARGS(*header), nxm_length(*header), nxm_header_len(*header)); goto error; } ofpbuf_pull(b, nxm_header_len(*header)); if (field) { *field = mf_from_oxm_header(*header, vl_mff_map); if (!*field && !(allow_cookie && is_cookie_pseudoheader(*header))) { VLOG_DBG_RL(&rl, "OXM header "NXM_HEADER_FMT" is unknown", NXM_HEADER_ARGS(*header)); return OFPERR_OFPBMC_BAD_FIELD; } else if (mf_vl_mff_invalid(*field, vl_mff_map)) { return OFPERR_NXFMFC_INVALID_TLV_FIELD; } } return 0; bad_len: VLOG_DBG_RL(&rl, "encountered partial (%"PRIu32"-byte) OXM entry", b->size); error: *header = 0; if (field) { *field = NULL; } return OFPERR_OFPBMC_BAD_LEN; } static void copy_entry_value(const struct mf_field *field, union mf_value *value, const uint8_t *payload, int width) { int copy_len; void *copy_dst; copy_dst = value; copy_len = MIN(width, field ? field->n_bytes : sizeof *value); if (field && field->variable_len) { memset(value, 0, field->n_bytes); copy_dst = &value->u8 + field->n_bytes - copy_len; } memcpy(copy_dst, payload, copy_len); } static enum ofperr nx_pull_entry__(struct ofpbuf *b, bool allow_cookie, const struct vl_mff_map *vl_mff_map, uint64_t *header, const struct mf_field **field_, union mf_value *value, union mf_value *mask) { const struct mf_field *field; enum ofperr header_error; unsigned int payload_len; const uint8_t *payload; int width; header_error = nx_pull_header__(b, allow_cookie, vl_mff_map, header, &field); if (header_error && header_error != OFPERR_OFPBMC_BAD_FIELD) { return header_error; } payload_len = nxm_payload_len(*header); payload = ofpbuf_try_pull(b, payload_len); if (!payload) { VLOG_DBG_RL(&rl, "OXM header "NXM_HEADER_FMT" calls for %u-byte " "payload but only %"PRIu32" bytes follow OXM header", NXM_HEADER_ARGS(*header), payload_len, b->size); return OFPERR_OFPBMC_BAD_LEN; } width = nxm_field_bytes(*header); if (nxm_hasmask(*header) && !is_mask_consistent(*header, payload, payload + width)) { return OFPERR_OFPBMC_BAD_WILDCARDS; } copy_entry_value(field, value, payload, width); if (mask) { if (nxm_hasmask(*header)) { copy_entry_value(field, mask, payload + width, width); } else { memset(mask, 0xff, sizeof *mask); } } else if (nxm_hasmask(*header)) { VLOG_DBG_RL(&rl, "OXM header "NXM_HEADER_FMT" includes mask but " "masked OXMs are not allowed here", NXM_HEADER_ARGS(*header)); return OFPERR_OFPBMC_BAD_MASK; } if (field_) { *field_ = field; return header_error; } return 0; } /* Attempts to pull an NXM or OXM header, value, and mask (if present) from the * beginning of 'b'. If successful, stores a pointer to the "struct mf_field" * corresponding to the pulled header in '*field', the value into '*value', * and the mask into '*mask', and returns 0. On error, returns an OpenFlow * error; in this case, some bytes might have been pulled off 'b' anyhow, and * the output parameters might have been modified. * * If a NULL 'mask' is supplied, masked OXM or NXM entries are treated as * errors (with OFPERR_OFPBMC_BAD_MASK). */ enum ofperr nx_pull_entry(struct ofpbuf *b, const struct vl_mff_map *vl_mff_map, const struct mf_field **field, union mf_value *value, union mf_value *mask) { uint64_t header; return nx_pull_entry__(b, false, vl_mff_map, &header, field, value, mask); } /* Attempts to pull an NXM or OXM header from the beginning of 'b'. If * successful, stores a pointer to the "struct mf_field" corresponding to the * pulled header in '*field', stores the header's hasmask bit in '*masked' * (true if hasmask=1, false if hasmask=0), and returns 0. On error, returns * an OpenFlow error; in this case, some bytes might have been pulled off 'b' * anyhow, and the output parameters might have been modified. * * If NULL 'masked' is supplied, masked OXM or NXM headers are treated as * errors (with OFPERR_OFPBMC_BAD_MASK). */ enum ofperr nx_pull_header(struct ofpbuf *b, const struct vl_mff_map *vl_mff_map, const struct mf_field **field, bool *masked) { enum ofperr error; uint64_t header; error = nx_pull_header__(b, false, vl_mff_map, &header, field); if (masked) { *masked = !error && nxm_hasmask(header); } else if (!error && nxm_hasmask(header)) { error = OFPERR_OFPBMC_BAD_MASK; } return error; } static enum ofperr nx_pull_match_entry(struct ofpbuf *b, bool allow_cookie, const struct vl_mff_map *vl_mff_map, const struct mf_field **field, union mf_value *value, union mf_value *mask) { enum ofperr error; uint64_t header; error = nx_pull_entry__(b, allow_cookie, vl_mff_map, &header, field, value, mask); if (error) { return error; } if (field && *field) { if (!mf_is_mask_valid(*field, mask)) { VLOG_DBG_RL(&rl, "bad mask for field %s", (*field)->name); return OFPERR_OFPBMC_BAD_MASK; } if (!mf_is_value_valid(*field, value)) { VLOG_DBG_RL(&rl, "bad value for field %s", (*field)->name); return OFPERR_OFPBMC_BAD_VALUE; } } return 0; } /* Prerequisites will only be checked when 'strict' is 'true'. This allows * decoding conntrack original direction 5-tuple IP addresses without the * ethertype being present, when decoding metadata only. */ static enum ofperr nx_pull_raw(const uint8_t *p, unsigned int match_len, bool strict, bool pipeline_fields_only, struct match *match, ovs_be64 *cookie, ovs_be64 *cookie_mask, const struct tun_table *tun_table, const struct vl_mff_map *vl_mff_map) { ovs_assert((cookie != NULL) == (cookie_mask != NULL)); match_init_catchall(match); match->flow.tunnel.metadata.tab = tun_table; if (cookie) { *cookie = *cookie_mask = htonll(0); } struct ofpbuf b = ofpbuf_const_initializer(p, match_len); while (b.size) { const uint8_t *pos = b.data; const struct mf_field *field; union mf_value value; union mf_value mask; enum ofperr error; error = nx_pull_match_entry(&b, cookie != NULL, vl_mff_map, &field, &value, &mask); if (error) { if (error == OFPERR_OFPBMC_BAD_FIELD && !strict) { continue; } } else if (!field) { if (!cookie) { error = OFPERR_OFPBMC_BAD_FIELD; } else if (*cookie_mask) { error = OFPERR_OFPBMC_DUP_FIELD; } else { *cookie = value.be64; *cookie_mask = mask.be64; } } else if (strict && !mf_are_match_prereqs_ok(field, match)) { error = OFPERR_OFPBMC_BAD_PREREQ; } else if (!mf_is_all_wild(field, &match->wc)) { error = OFPERR_OFPBMC_DUP_FIELD; } else if (pipeline_fields_only && !mf_is_pipeline_field(field)) { error = OFPERR_OFPBRC_PIPELINE_FIELDS_ONLY; } else { char *err_str; mf_set(field, &value, &mask, match, &err_str); if (err_str) { VLOG_DBG_RL(&rl, "error parsing OXM at offset %"PRIdPTR" " "within match (%s)", pos - p, err_str); free(err_str); return OFPERR_OFPBMC_BAD_VALUE; } match_add_ethernet_prereq(match, field); } if (error) { VLOG_DBG_RL(&rl, "error parsing OXM at offset %"PRIdPTR" " "within match (%s)", pos - p, ofperr_to_string(error)); return error; } } match->flow.tunnel.metadata.tab = NULL; return 0; } static enum ofperr nx_pull_match__(struct ofpbuf *b, unsigned int match_len, bool strict, bool pipeline_fields_only, struct match *match, ovs_be64 *cookie, ovs_be64 *cookie_mask, const struct tun_table *tun_table, const struct vl_mff_map *vl_mff_map) { uint8_t *p = NULL; if (match_len) { p = ofpbuf_try_pull(b, ROUND_UP(match_len, 8)); if (!p) { VLOG_DBG_RL(&rl, "nx_match length %u, rounded up to a " "multiple of 8, is longer than space in message (max " "length %"PRIu32")", match_len, b->size); return OFPERR_OFPBMC_BAD_LEN; } } return nx_pull_raw(p, match_len, strict, pipeline_fields_only, match, cookie, cookie_mask, tun_table, vl_mff_map); } /* Parses the nx_match formatted match description in 'b' with length * 'match_len'. Stores the results in 'match'. If 'cookie' and 'cookie_mask' * are valid pointers, then stores the cookie and mask in them if 'b' contains * a "NXM_NX_COOKIE*" match. Otherwise, stores 0 in both. * If 'pipeline_fields_only' is true, this function returns * OFPERR_OFPBRC_PIPELINE_FIELDS_ONLY if there is any non pipeline fields * in 'b'. * * 'vl_mff_map" is an optional parameter that is used to validate the length * of variable length mf_fields in 'match'. If it is not provided, the * default mf_fields with maximum length will be used. * * Fails with an error upon encountering an unknown NXM header. * * Returns 0 if successful, otherwise an OpenFlow error code. */ enum ofperr nx_pull_match(struct ofpbuf *b, unsigned int match_len, struct match *match, ovs_be64 *cookie, ovs_be64 *cookie_mask, bool pipeline_fields_only, const struct tun_table *tun_table, const struct vl_mff_map *vl_mff_map) { return nx_pull_match__(b, match_len, true, pipeline_fields_only, match, cookie, cookie_mask, tun_table, vl_mff_map); } /* Behaves the same as nx_pull_match(), but skips over unknown NXM headers, * instead of failing with an error, and does not check for field * prerequisites. */ enum ofperr nx_pull_match_loose(struct ofpbuf *b, unsigned int match_len, struct match *match, ovs_be64 *cookie, ovs_be64 *cookie_mask, bool pipeline_fields_only, const struct tun_table *tun_table) { return nx_pull_match__(b, match_len, false, pipeline_fields_only, match, cookie, cookie_mask, tun_table, NULL); } static enum ofperr oxm_pull_match__(struct ofpbuf *b, bool strict, bool pipeline_fields_only, const struct tun_table *tun_table, const struct vl_mff_map *vl_mff_map, struct match *match) { struct ofp11_match_header *omh = b->data; uint8_t *p; uint16_t match_len; if (b->size < sizeof *omh) { return OFPERR_OFPBMC_BAD_LEN; } match_len = ntohs(omh->length); if (match_len < sizeof *omh) { return OFPERR_OFPBMC_BAD_LEN; } if (omh->type != htons(OFPMT_OXM)) { return OFPERR_OFPBMC_BAD_TYPE; } p = ofpbuf_try_pull(b, ROUND_UP(match_len, 8)); if (!p) { VLOG_DBG_RL(&rl, "oxm length %u, rounded up to a " "multiple of 8, is longer than space in message (max " "length %"PRIu32")", match_len, b->size); return OFPERR_OFPBMC_BAD_LEN; } return nx_pull_raw(p + sizeof *omh, match_len - sizeof *omh, strict, pipeline_fields_only, match, NULL, NULL, tun_table, vl_mff_map); } /* Parses the oxm formatted match description preceded by a struct * ofp11_match_header in 'b'. Stores the result in 'match'. * If 'pipeline_fields_only' is true, this function returns * OFPERR_OFPBRC_PIPELINE_FIELDS_ONLY if there is any non pipeline fields * in 'b'. * * 'vl_mff_map' is an optional parameter that is used to validate the length * of variable length mf_fields in 'match'. If it is not provided, the * default mf_fields with maximum length will be used. * * Fails with an error when encountering unknown OXM headers. * * Returns 0 if successful, otherwise an OpenFlow error code. */ enum ofperr oxm_pull_match(struct ofpbuf *b, bool pipeline_fields_only, const struct tun_table *tun_table, const struct vl_mff_map *vl_mff_map, struct match *match) { return oxm_pull_match__(b, true, pipeline_fields_only, tun_table, vl_mff_map, match); } /* Behaves the same as oxm_pull_match() with two exceptions. Skips over * unknown OXM headers instead of failing with an error when they are * encountered, and does not check for field prerequisites. */ enum ofperr oxm_pull_match_loose(struct ofpbuf *b, bool pipeline_fields_only, const struct tun_table *tun_table, struct match *match) { return oxm_pull_match__(b, false, pipeline_fields_only, tun_table, NULL, match); } /* Parses the OXM match description in the 'oxm_len' bytes in 'oxm'. Stores * the result in 'match'. * * Returns 0 if successful, otherwise an OpenFlow error code. * * If 'loose' is true, encountering unknown OXM headers or missing field * prerequisites are not considered as error conditions. */ enum ofperr oxm_decode_match(const void *oxm, size_t oxm_len, bool loose, const struct tun_table *tun_table, const struct vl_mff_map *vl_mff_map, struct match *match) { return nx_pull_raw(oxm, oxm_len, !loose, false, match, NULL, NULL, tun_table, vl_mff_map); } /* Verify an array of OXM TLVs treating value of each TLV as a mask, * disallowing masks in each TLV and ignoring pre-requisites. */ enum ofperr oxm_pull_field_array(const void *fields_data, size_t fields_len, struct field_array *fa) { struct ofpbuf b = ofpbuf_const_initializer(fields_data, fields_len); while (b.size) { const uint8_t *pos = b.data; const struct mf_field *field; union mf_value value; enum ofperr error; uint64_t header; error = nx_pull_entry__(&b, false, NULL, &header, &field, &value, NULL); if (error) { VLOG_DBG_RL(&rl, "error pulling field array field"); return error; } else if (!field) { VLOG_DBG_RL(&rl, "unknown field array field"); error = OFPERR_OFPBMC_BAD_FIELD; } else if (bitmap_is_set(fa->used.bm, field->id)) { VLOG_DBG_RL(&rl, "duplicate field array field '%s'", field->name); error = OFPERR_OFPBMC_DUP_FIELD; } else if (!mf_is_mask_valid(field, &value)) { VLOG_DBG_RL(&rl, "bad mask in field array field '%s'", field->name); return OFPERR_OFPBMC_BAD_MASK; } else { field_array_set(field->id, &value, fa); } if (error) { const uint8_t *start = fields_data; VLOG_DBG_RL(&rl, "error parsing OXM at offset %"PRIdPTR" " "within field array (%s)", pos - start, ofperr_to_string(error)); return error; } } return 0; } /* nx_put_match() and helpers. * * 'put' functions whose names end in 'w' add a wildcarded field. * 'put' functions whose names end in 'm' add a field that might be wildcarded. * Other 'put' functions add exact-match fields. */ struct nxm_put_ctx { struct ofpbuf *output; bool implied_ethernet; }; void nxm_put_entry_raw(struct ofpbuf *b, enum mf_field_id field, enum ofp_version version, const void *value, const void *mask, size_t n_bytes) { nx_put_header_len(b, field, version, !!mask, n_bytes); ofpbuf_put(b, value, n_bytes); if (mask) { ofpbuf_put(b, mask, n_bytes); } } static void nxm_put__(struct nxm_put_ctx *ctx, enum mf_field_id field, enum ofp_version version, const void *value, const void *mask, size_t n_bytes) { nxm_put_entry_raw(ctx->output, field, version, value, mask, n_bytes); if (!ctx->implied_ethernet && mf_from_id(field)->prereqs != MFP_NONE) { ctx->implied_ethernet = true; } } static void nxm_put(struct nxm_put_ctx *ctx, enum mf_field_id field, enum ofp_version version, const void *value, const void *mask, size_t n_bytes) { if (!is_all_zeros(mask, n_bytes)) { bool masked = !is_all_ones(mask, n_bytes); nxm_put__(ctx, field, version, value, masked ? mask : NULL, n_bytes); } } static void nxm_put_8m(struct nxm_put_ctx *ctx, enum mf_field_id field, enum ofp_version version, uint8_t value, uint8_t mask) { nxm_put(ctx, field, version, &value, &mask, sizeof value); } static void nxm_put_8(struct nxm_put_ctx *ctx, enum mf_field_id field, enum ofp_version version, uint8_t value) { nxm_put__(ctx, field, version, &value, NULL, sizeof value); } static void nxm_put_16m(struct nxm_put_ctx *ctx, enum mf_field_id field, enum ofp_version version, ovs_be16 value, ovs_be16 mask) { nxm_put(ctx, field, version, &value, &mask, sizeof value); } static void nxm_put_16(struct nxm_put_ctx *ctx, enum mf_field_id field, enum ofp_version version, ovs_be16 value) { nxm_put__(ctx, field, version, &value, NULL, sizeof value); } static void nxm_put_32m(struct nxm_put_ctx *ctx, enum mf_field_id field, enum ofp_version version, ovs_be32 value, ovs_be32 mask) { nxm_put(ctx, field, version, &value, &mask, sizeof value); } static void nxm_put_32(struct nxm_put_ctx *ctx, enum mf_field_id field, enum ofp_version version, ovs_be32 value) { nxm_put__(ctx, field, version, &value, NULL, sizeof value); } static void nxm_put_64m(struct nxm_put_ctx *ctx, enum mf_field_id field, enum ofp_version version, ovs_be64 value, ovs_be64 mask) { nxm_put(ctx, field, version, &value, &mask, sizeof value); } static void nxm_put_128m(struct nxm_put_ctx *ctx, enum mf_field_id field, enum ofp_version version, const ovs_be128 value, const ovs_be128 mask) { nxm_put(ctx, field, version, &value, &mask, sizeof(value)); } static void nxm_put_eth_masked(struct nxm_put_ctx *ctx, enum mf_field_id field, enum ofp_version version, const struct eth_addr value, const struct eth_addr mask) { nxm_put(ctx, field, version, value.ea, mask.ea, ETH_ADDR_LEN); } static void nxm_put_ipv6(struct nxm_put_ctx *ctx, enum mf_field_id field, enum ofp_version version, const struct in6_addr *value, const struct in6_addr *mask) { nxm_put(ctx, field, version, value->s6_addr, mask->s6_addr, sizeof value->s6_addr); } static void nxm_put_frag(struct nxm_put_ctx *ctx, const struct match *match, enum ofp_version version) { uint8_t nw_frag = match->flow.nw_frag & FLOW_NW_FRAG_MASK; uint8_t nw_frag_mask = match->wc.masks.nw_frag & FLOW_NW_FRAG_MASK; nxm_put_8m(ctx, MFF_IP_FRAG, version, nw_frag, nw_frag_mask == FLOW_NW_FRAG_MASK ? UINT8_MAX : nw_frag_mask); } /* Appends to 'b' a set of OXM or NXM matches for the IPv4 or IPv6 fields in * 'match'. */ static void nxm_put_ip(struct nxm_put_ctx *ctx, const struct match *match, enum ofp_version oxm) { const struct flow *flow = &match->flow; ovs_be16 dl_type = get_dl_type(flow); if (dl_type == htons(ETH_TYPE_IP)) { nxm_put_32m(ctx, MFF_IPV4_SRC, oxm, flow->nw_src, match->wc.masks.nw_src); nxm_put_32m(ctx, MFF_IPV4_DST, oxm, flow->nw_dst, match->wc.masks.nw_dst); } else { nxm_put_ipv6(ctx, MFF_IPV6_SRC, oxm, &flow->ipv6_src, &match->wc.masks.ipv6_src); nxm_put_ipv6(ctx, MFF_IPV6_DST, oxm, &flow->ipv6_dst, &match->wc.masks.ipv6_dst); } nxm_put_frag(ctx, match, oxm); if (match->wc.masks.nw_tos & IP_DSCP_MASK) { if (oxm) { nxm_put_8(ctx, MFF_IP_DSCP_SHIFTED, oxm, flow->nw_tos >> 2); } else { nxm_put_8(ctx, MFF_IP_DSCP, oxm, flow->nw_tos & IP_DSCP_MASK); } } if (match->wc.masks.nw_tos & IP_ECN_MASK) { nxm_put_8(ctx, MFF_IP_ECN, oxm, flow->nw_tos & IP_ECN_MASK); } if (match->wc.masks.nw_ttl) { nxm_put_8(ctx, MFF_IP_TTL, oxm, flow->nw_ttl); } nxm_put_32m(ctx, MFF_IPV6_LABEL, oxm, flow->ipv6_label, match->wc.masks.ipv6_label); if (match->wc.masks.nw_proto) { nxm_put_8(ctx, MFF_IP_PROTO, oxm, flow->nw_proto); if (flow->nw_proto == IPPROTO_TCP) { nxm_put_16m(ctx, MFF_TCP_SRC, oxm, flow->tp_src, match->wc.masks.tp_src); nxm_put_16m(ctx, MFF_TCP_DST, oxm, flow->tp_dst, match->wc.masks.tp_dst); nxm_put_16m(ctx, MFF_TCP_FLAGS, oxm, flow->tcp_flags, match->wc.masks.tcp_flags); } else if (flow->nw_proto == IPPROTO_UDP) { nxm_put_16m(ctx, MFF_UDP_SRC, oxm, flow->tp_src, match->wc.masks.tp_src); nxm_put_16m(ctx, MFF_UDP_DST, oxm, flow->tp_dst, match->wc.masks.tp_dst); } else if (flow->nw_proto == IPPROTO_SCTP) { nxm_put_16m(ctx, MFF_SCTP_SRC, oxm, flow->tp_src, match->wc.masks.tp_src); nxm_put_16m(ctx, MFF_SCTP_DST, oxm, flow->tp_dst, match->wc.masks.tp_dst); } else if (is_icmpv4(flow, NULL)) { if (match->wc.masks.tp_src) { nxm_put_8(ctx, MFF_ICMPV4_TYPE, oxm, ntohs(flow->tp_src)); } if (match->wc.masks.tp_dst) { nxm_put_8(ctx, MFF_ICMPV4_CODE, oxm, ntohs(flow->tp_dst)); } } else if (is_icmpv6(flow, NULL)) { if (match->wc.masks.tp_src) { nxm_put_8(ctx, MFF_ICMPV6_TYPE, oxm, ntohs(flow->tp_src)); } if (match->wc.masks.tp_dst) { nxm_put_8(ctx, MFF_ICMPV6_CODE, oxm, ntohs(flow->tp_dst)); } if (is_nd(flow, NULL)) { nxm_put_ipv6(ctx, MFF_ND_TARGET, oxm, &flow->nd_target, &match->wc.masks.nd_target); if (flow->tp_src == htons(ND_NEIGHBOR_SOLICIT)) { nxm_put_eth_masked(ctx, MFF_ND_SLL, oxm, flow->arp_sha, match->wc.masks.arp_sha); } if (flow->tp_src == htons(ND_NEIGHBOR_ADVERT)) { nxm_put_eth_masked(ctx, MFF_ND_TLL, oxm, flow->arp_tha, match->wc.masks.arp_tha); } } } } } /* Appends to 'b' the nx_match format that expresses 'match'. For Flow Mod and * Flow Stats Requests messages, a 'cookie' and 'cookie_mask' may be supplied. * Otherwise, 'cookie_mask' should be zero. * * Specify 'oxm' as 0 to express the match in NXM format; otherwise, specify * 'oxm' as the OpenFlow version number for the OXM format to use. * * This function can cause 'b''s data to be reallocated. * * Returns the number of bytes appended to 'b', excluding padding. * * If 'match' is a catch-all rule that matches every packet, then this function * appends nothing to 'b' and returns 0. */ static int nx_put_raw(struct ofpbuf *b, enum ofp_version oxm, const struct match *match, ovs_be64 cookie, ovs_be64 cookie_mask) { const struct flow *flow = &match->flow; const size_t start_len = b->size; ovs_be16 dl_type = get_dl_type(flow); ovs_be32 spi_mask; int match_len; int i; BUILD_ASSERT_DECL(FLOW_WC_SEQ == 40); struct nxm_put_ctx ctx = { .output = b, .implied_ethernet = false }; /* OpenFlow Packet Type. Must be first. */ if (match->wc.masks.packet_type && !match_has_default_packet_type(match)) { nxm_put_32m(&ctx, MFF_PACKET_TYPE, oxm, flow->packet_type, match->wc.masks.packet_type); } /* Metadata. */ if (match->wc.masks.dp_hash) { nxm_put_32m(&ctx, MFF_DP_HASH, oxm, htonl(flow->dp_hash), htonl(match->wc.masks.dp_hash)); } if (match->wc.masks.recirc_id) { nxm_put_32(&ctx, MFF_RECIRC_ID, oxm, htonl(flow->recirc_id)); } if (match->wc.masks.conj_id) { nxm_put_32(&ctx, MFF_CONJ_ID, oxm, htonl(flow->conj_id)); } if (match->wc.masks.in_port.ofp_port) { ofp_port_t in_port = flow->in_port.ofp_port; if (oxm) { nxm_put_32(&ctx, MFF_IN_PORT_OXM, oxm, ofputil_port_to_ofp11(in_port)); } else { nxm_put_16(&ctx, MFF_IN_PORT, oxm, htons(ofp_to_u16(in_port))); } } if (match->wc.masks.actset_output) { nxm_put_32(&ctx, MFF_ACTSET_OUTPUT, oxm, ofputil_port_to_ofp11(flow->actset_output)); } /* Ethernet. */ nxm_put_eth_masked(&ctx, MFF_ETH_SRC, oxm, flow->dl_src, match->wc.masks.dl_src); nxm_put_eth_masked(&ctx, MFF_ETH_DST, oxm, flow->dl_dst, match->wc.masks.dl_dst); nxm_put_16m(&ctx, MFF_ETH_TYPE, oxm, ofputil_dl_type_to_openflow(flow->dl_type), match->wc.masks.dl_type); /* 802.1Q. */ if (oxm) { ovs_be16 VID_CFI_MASK = htons(VLAN_VID_MASK | VLAN_CFI); ovs_be16 vid = flow->vlans[0].tci & VID_CFI_MASK; ovs_be16 mask = match->wc.masks.vlans[0].tci & VID_CFI_MASK; if (mask == htons(VLAN_VID_MASK | VLAN_CFI)) { nxm_put_16(&ctx, MFF_VLAN_VID, oxm, vid); } else if (mask) { nxm_put_16m(&ctx, MFF_VLAN_VID, oxm, vid, mask); } if (vid && vlan_tci_to_pcp(match->wc.masks.vlans[0].tci)) { nxm_put_8(&ctx, MFF_VLAN_PCP, oxm, vlan_tci_to_pcp(flow->vlans[0].tci)); } } else { nxm_put_16m(&ctx, MFF_VLAN_TCI, oxm, flow->vlans[0].tci, match->wc.masks.vlans[0].tci); } /* MPLS. */ if (eth_type_mpls(dl_type)) { if (match->wc.masks.mpls_lse[0] & htonl(MPLS_TC_MASK)) { nxm_put_8(&ctx, MFF_MPLS_TC, oxm, mpls_lse_to_tc(flow->mpls_lse[0])); } if (match->wc.masks.mpls_lse[0] & htonl(MPLS_BOS_MASK)) { nxm_put_8(&ctx, MFF_MPLS_BOS, oxm, mpls_lse_to_bos(flow->mpls_lse[0])); } if (match->wc.masks.mpls_lse[0] & htonl(MPLS_LABEL_MASK)) { nxm_put_32(&ctx, MFF_MPLS_LABEL, oxm, htonl(mpls_lse_to_label(flow->mpls_lse[0]))); } } /* L3. */ if (is_ip_any(flow)) { nxm_put_ip(&ctx, match, oxm); } else if (dl_type == htons(ETH_TYPE_ARP) || dl_type == htons(ETH_TYPE_RARP)) { /* ARP. */ if (match->wc.masks.nw_proto) { nxm_put_16(&ctx, MFF_ARP_OP, oxm, htons(flow->nw_proto)); } nxm_put_32m(&ctx, MFF_ARP_SPA, oxm, flow->nw_src, match->wc.masks.nw_src); nxm_put_32m(&ctx, MFF_ARP_TPA, oxm, flow->nw_dst, match->wc.masks.nw_dst); nxm_put_eth_masked(&ctx, MFF_ARP_SHA, oxm, flow->arp_sha, match->wc.masks.arp_sha); nxm_put_eth_masked(&ctx, MFF_ARP_THA, oxm, flow->arp_tha, match->wc.masks.arp_tha); } /* Tunnel ID. */ nxm_put_64m(&ctx, MFF_TUN_ID, oxm, flow->tunnel.tun_id, match->wc.masks.tunnel.tun_id); /* Other tunnel metadata. */ nxm_put_16m(&ctx, MFF_TUN_FLAGS, oxm, htons(flow->tunnel.flags), htons(match->wc.masks.tunnel.flags)); nxm_put_32m(&ctx, MFF_TUN_SRC, oxm, flow->tunnel.ip_src, match->wc.masks.tunnel.ip_src); nxm_put_32m(&ctx, MFF_TUN_DST, oxm, flow->tunnel.ip_dst, match->wc.masks.tunnel.ip_dst); nxm_put_ipv6(&ctx, MFF_TUN_IPV6_SRC, oxm, &flow->tunnel.ipv6_src, &match->wc.masks.tunnel.ipv6_src); nxm_put_ipv6(&ctx, MFF_TUN_IPV6_DST, oxm, &flow->tunnel.ipv6_dst, &match->wc.masks.tunnel.ipv6_dst); nxm_put_16m(&ctx, MFF_TUN_GBP_ID, oxm, flow->tunnel.gbp_id, match->wc.masks.tunnel.gbp_id); nxm_put_8m(&ctx, MFF_TUN_GBP_FLAGS, oxm, flow->tunnel.gbp_flags, match->wc.masks.tunnel.gbp_flags); tun_metadata_to_nx_match(b, oxm, match); /* Network Service Header */ nxm_put_8m(&ctx, MFF_NSH_FLAGS, oxm, flow->nsh.flags, match->wc.masks.nsh.flags); nxm_put_8m(&ctx, MFF_NSH_TTL, oxm, flow->nsh.ttl, match->wc.masks.nsh.ttl); nxm_put_8m(&ctx, MFF_NSH_MDTYPE, oxm, flow->nsh.mdtype, match->wc.masks.nsh.mdtype); nxm_put_8m(&ctx, MFF_NSH_NP, oxm, flow->nsh.np, match->wc.masks.nsh.np); spi_mask = nsh_path_hdr_to_spi(match->wc.masks.nsh.path_hdr); if (spi_mask == htonl(NSH_SPI_MASK >> NSH_SPI_SHIFT)) { spi_mask = OVS_BE32_MAX; } nxm_put_32m(&ctx, MFF_NSH_SPI, oxm, nsh_path_hdr_to_spi(flow->nsh.path_hdr), spi_mask); nxm_put_8m(&ctx, MFF_NSH_SI, oxm, nsh_path_hdr_to_si(flow->nsh.path_hdr), nsh_path_hdr_to_si(match->wc.masks.nsh.path_hdr)); for (int i = 0; i < 4; i++) { nxm_put_32m(&ctx, MFF_NSH_C1 + i, oxm, flow->nsh.context[i], match->wc.masks.nsh.context[i]); } /* Registers. */ if (oxm < OFP15_VERSION) { for (i = 0; i < FLOW_N_REGS; i++) { nxm_put_32m(&ctx, MFF_REG0 + i, oxm, htonl(flow->regs[i]), htonl(match->wc.masks.regs[i])); } } else { for (i = 0; i < FLOW_N_XREGS; i++) { nxm_put_64m(&ctx, MFF_XREG0 + i, oxm, htonll(flow_get_xreg(flow, i)), htonll(flow_get_xreg(&match->wc.masks, i))); } } /* Packet mark. */ nxm_put_32m(&ctx, MFF_PKT_MARK, oxm, htonl(flow->pkt_mark), htonl(match->wc.masks.pkt_mark)); /* Connection tracking. */ nxm_put_32m(&ctx, MFF_CT_STATE, oxm, htonl(flow->ct_state), htonl(match->wc.masks.ct_state)); nxm_put_16m(&ctx, MFF_CT_ZONE, oxm, htons(flow->ct_zone), htons(match->wc.masks.ct_zone)); nxm_put_32m(&ctx, MFF_CT_MARK, oxm, htonl(flow->ct_mark), htonl(match->wc.masks.ct_mark)); nxm_put_128m(&ctx, MFF_CT_LABEL, oxm, hton128(flow->ct_label), hton128(match->wc.masks.ct_label)); nxm_put_32m(&ctx, MFF_CT_NW_SRC, oxm, flow->ct_nw_src, match->wc.masks.ct_nw_src); nxm_put_ipv6(&ctx, MFF_CT_IPV6_SRC, oxm, &flow->ct_ipv6_src, &match->wc.masks.ct_ipv6_src); nxm_put_32m(&ctx, MFF_CT_NW_DST, oxm, flow->ct_nw_dst, match->wc.masks.ct_nw_dst); nxm_put_ipv6(&ctx, MFF_CT_IPV6_DST, oxm, &flow->ct_ipv6_dst, &match->wc.masks.ct_ipv6_dst); if (flow->ct_nw_proto) { nxm_put_8m(&ctx, MFF_CT_NW_PROTO, oxm, flow->ct_nw_proto, match->wc.masks.ct_nw_proto); nxm_put_16m(&ctx, MFF_CT_TP_SRC, oxm, flow->ct_tp_src, match->wc.masks.ct_tp_src); nxm_put_16m(&ctx, MFF_CT_TP_DST, oxm, flow->ct_tp_dst, match->wc.masks.ct_tp_dst); } /* OpenFlow 1.1+ Metadata. */ nxm_put_64m(&ctx, MFF_METADATA, oxm, flow->metadata, match->wc.masks.metadata); /* Cookie. */ if (cookie_mask) { bool masked = cookie_mask != OVS_BE64_MAX; cookie &= cookie_mask; nx_put_header__(b, NXM_NX_COOKIE, masked); ofpbuf_put(b, &cookie, sizeof cookie); if (masked) { ofpbuf_put(b, &cookie_mask, sizeof cookie_mask); } } if (match_has_default_packet_type(match) && !ctx.implied_ethernet) { uint64_t pt_stub[16 / 8]; struct ofpbuf pt; ofpbuf_use_stack(&pt, pt_stub, sizeof pt_stub); nxm_put_entry_raw(&pt, MFF_PACKET_TYPE, oxm, &flow->packet_type, NULL, sizeof flow->packet_type); ofpbuf_insert(b, start_len, pt.data, pt.size); } match_len = b->size - start_len; return match_len; } /* Appends to 'b' the nx_match format that expresses 'match', plus enough zero * bytes to pad the nx_match out to a multiple of 8. For Flow Mod and Flow * Stats Requests messages, a 'cookie' and 'cookie_mask' may be supplied. * Otherwise, 'cookie_mask' should be zero. * * This function can cause 'b''s data to be reallocated. * * Returns the number of bytes appended to 'b', excluding padding. The return * value can be zero if it appended nothing at all to 'b' (which happens if * 'cr' is a catch-all rule that matches every packet). */ int nx_put_match(struct ofpbuf *b, const struct match *match, ovs_be64 cookie, ovs_be64 cookie_mask) { int match_len = nx_put_raw(b, 0, match, cookie, cookie_mask); ofpbuf_put_zeros(b, PAD_SIZE(match_len, 8)); return match_len; } /* Appends to 'b' an struct ofp11_match_header followed by the OXM format that * expresses 'match', plus enough zero bytes to pad the data appended out to a * multiple of 8. * * OXM differs slightly among versions of OpenFlow. Specify the OpenFlow * version in use as 'version'. * * This function can cause 'b''s data to be reallocated. * * Returns the number of bytes appended to 'b', excluding the padding. Never * returns zero. */ int oxm_put_match(struct ofpbuf *b, const struct match *match, enum ofp_version version) { int match_len; struct ofp11_match_header *omh; size_t start_len = b->size; ovs_be64 cookie = htonll(0), cookie_mask = htonll(0); ofpbuf_put_uninit(b, sizeof *omh); match_len = (nx_put_raw(b, version, match, cookie, cookie_mask) + sizeof *omh); ofpbuf_put_zeros(b, PAD_SIZE(match_len, 8)); omh = ofpbuf_at(b, start_len, sizeof *omh); omh->type = htons(OFPMT_OXM); omh->length = htons(match_len); return match_len; } /* Appends to 'b' the OXM formats that expresses 'match', without header or * padding. * * OXM differs slightly among versions of OpenFlow. Specify the OpenFlow * version in use as 'version'. * * This function can cause 'b''s data to be reallocated. */ void oxm_put_raw(struct ofpbuf *b, const struct match *match, enum ofp_version version) { nx_put_raw(b, version, match, 0, 0); } /* Appends to 'b' the nx_match format that expresses the tlv corresponding * to 'id'. If mask is not all-ones then it is also formated as the value * of the tlv. */ static void nx_format_mask_tlv(struct ds *ds, enum mf_field_id id, const union mf_value *mask) { const struct mf_field *mf = mf_from_id(id); ds_put_format(ds, "%s", mf->name); if (!is_all_ones(mask, mf->n_bytes)) { ds_put_char(ds, '='); mf_format(mf, mask, NULL, NULL, ds); } ds_put_char(ds, ','); } /* Appends a string representation of 'fa_' to 'ds'. * The TLVS value of 'fa_' is treated as a mask and * only the name of fields is formated if it is all ones. */ void oxm_format_field_array(struct ds *ds, const struct field_array *fa) { size_t start_len = ds->length; size_t i, offset = 0; BITMAP_FOR_EACH_1 (i, MFF_N_IDS, fa->used.bm) { const struct mf_field *mf = mf_from_id(i); union mf_value value; memcpy(&value, fa->values + offset, mf->n_bytes); nx_format_mask_tlv(ds, i, &value); offset += mf->n_bytes; } if (ds->length > start_len) { ds_chomp(ds, ','); } } /* Appends to 'b' a series of OXM TLVs corresponding to the series * of enum mf_field_id and value tuples in 'fa_'. * * OXM differs slightly among versions of OpenFlow. Specify the OpenFlow * version in use as 'version'. * * This function can cause 'b''s data to be reallocated. * * Returns the number of bytes appended to 'b'. May return zero. */ int oxm_put_field_array(struct ofpbuf *b, const struct field_array *fa, enum ofp_version version) { size_t start_len = b->size; /* Field arrays are only used with the group selection method * property and group properties are only available in OpenFlow 1.5+. * So the following assertion should never fail. * * If support for older OpenFlow versions is desired then some care * will need to be taken of different TLVs that handle the same * flow fields. In particular: * - VLAN_TCI, VLAN_VID and MFF_VLAN_PCP * - IP_DSCP_MASK and DSCP_SHIFTED * - REGS and XREGS */ ovs_assert(version >= OFP15_VERSION); size_t i, offset = 0; BITMAP_FOR_EACH_1 (i, MFF_N_IDS, fa->used.bm) { const struct mf_field *mf = mf_from_id(i); union mf_value value; memcpy(&value, fa->values + offset, mf->n_bytes); int len = mf_field_len(mf, &value, NULL, NULL); nxm_put_entry_raw(b, i, version, &value + mf->n_bytes - len, NULL, len); offset += mf->n_bytes; } return b->size - start_len; } static void nx_put_header__(struct ofpbuf *b, uint64_t header, bool masked) { uint64_t masked_header = masked ? nxm_make_wild_header(header) : header; ovs_be64 network_header = htonll(masked_header); ofpbuf_put(b, &network_header, nxm_header_len(header)); } void nx_put_header(struct ofpbuf *b, enum mf_field_id field, enum ofp_version version, bool masked) { nx_put_header__(b, mf_oxm_header(field, version), masked); } void nx_put_mff_header(struct ofpbuf *b, const struct mf_field *mff, enum ofp_version version, bool masked) { if (mff->mapped) { nx_put_header_len(b, mff->id, version, masked, mff->n_bytes); } else { nx_put_header(b, mff->id, version, masked); } } static void nx_put_header_len(struct ofpbuf *b, enum mf_field_id field, enum ofp_version version, bool masked, size_t n_bytes) { uint64_t header = mf_oxm_header(field, version); header = NXM_HEADER(nxm_vendor(header), nxm_class(header), nxm_field(header), false, nxm_experimenter_len(header) + n_bytes); nx_put_header__(b, header, masked); } void nx_put_entry(struct ofpbuf *b, const struct mf_field *mff, enum ofp_version version, const union mf_value *value, const union mf_value *mask) { bool masked; int len, offset; len = mf_field_len(mff, value, mask, &masked); offset = mff->n_bytes - len; nxm_put_entry_raw(b, mff->id, version, &value->u8 + offset, masked ? &mask->u8 + offset : NULL, len); } /* nx_match_to_string() and helpers. */ static void format_nxm_field_name(struct ds *, uint64_t header); char * nx_match_to_string(const uint8_t *p, unsigned int match_len) { if (!match_len) { return xstrdup(""); } struct ofpbuf b = ofpbuf_const_initializer(p, match_len); struct ds s = DS_EMPTY_INITIALIZER; while (b.size) { union mf_value value; union mf_value mask; enum ofperr error; uint64_t header; int value_len; error = nx_pull_entry__(&b, true, NULL, &header, NULL, &value, &mask); if (error) { break; } value_len = MIN(sizeof value, nxm_field_bytes(header)); if (s.length) { ds_put_cstr(&s, ", "); } format_nxm_field_name(&s, header); ds_put_char(&s, '('); for (int i = 0; i < value_len; i++) { ds_put_format(&s, "%02x", ((const uint8_t *) &value)[i]); } if (nxm_hasmask(header)) { ds_put_char(&s, '/'); for (int i = 0; i < value_len; i++) { ds_put_format(&s, "%02x", ((const uint8_t *) &mask)[i]); } } ds_put_char(&s, ')'); } if (b.size) { if (s.length) { ds_put_cstr(&s, ", "); } ds_put_format(&s, "<%u invalid bytes>", b.size); } return ds_steal_cstr(&s); } char * oxm_match_to_string(const struct ofpbuf *p, unsigned int match_len) { const struct ofp11_match_header *omh = p->data; uint16_t match_len_; struct ds s; ds_init(&s); if (match_len < sizeof *omh) { ds_put_format(&s, "", match_len); goto err; } if (omh->type != htons(OFPMT_OXM)) { ds_put_format(&s, "", ntohs(omh->type)); goto err; } match_len_ = ntohs(omh->length); if (match_len_ < sizeof *omh) { ds_put_format(&s, "", match_len_); goto err; } if (match_len_ != match_len) { ds_put_format(&s, "", match_len_, match_len); goto err; } return nx_match_to_string(ofpbuf_at(p, sizeof *omh, 0), match_len - sizeof *omh); err: return ds_steal_cstr(&s); } void nx_format_field_name(enum mf_field_id id, enum ofp_version version, struct ds *s) { format_nxm_field_name(s, mf_oxm_header(id, version)); } static void format_nxm_field_name(struct ds *s, uint64_t header) { const struct nxm_field *f = nxm_field_by_header(header); if (f) { ds_put_cstr(s, f->name); if (nxm_hasmask(header)) { ds_put_cstr(s, "_W"); } } else if (header == NXM_NX_COOKIE) { ds_put_cstr(s, "NXM_NX_COOKIE"); } else if (header == NXM_NX_COOKIE_W) { ds_put_cstr(s, "NXM_NX_COOKIE_W"); } else { ds_put_format(s, "%d:%d", nxm_class(header), nxm_field(header)); } } static bool streq_len(const char *a, size_t a_len, const char *b) { return strlen(b) == a_len && !memcmp(a, b, a_len); } static uint64_t parse_nxm_field_name(const char *name, int name_len) { const struct nxm_field *f; bool wild; f = mf_parse_subfield_name(name, name_len, &wild); if (f) { if (!wild) { return f->header; } else if (mf_from_id(f->id)->maskable != MFM_NONE) { return nxm_make_wild_header(f->header); } } if (streq_len(name, name_len, "NXM_NX_COOKIE")) { return NXM_NX_COOKIE; } else if (streq_len(name, name_len, "NXM_NX_COOKIE_W")) { return NXM_NX_COOKIE_W; } /* Check whether it's a field header value as hex. * (This isn't ordinarily useful except for testing error behavior.) */ if (name_len == 8) { uint64_t header; bool ok; header = hexits_value(name, name_len, &ok) << 32; if (ok) { return header; } } else if (name_len == 16) { uint64_t header; bool ok; header = hexits_value(name, name_len, &ok); if (ok && is_experimenter_oxm(header)) { return header; } } return 0; } /* nx_match_from_string(). */ static int nx_match_from_string_raw(const char *s, struct ofpbuf *b) { const char *full_s = s; const size_t start_len = b->size; if (!strcmp(s, "")) { /* Ensure that 'b->data' isn't actually null. */ ofpbuf_prealloc_tailroom(b, 1); return 0; } for (s += strspn(s, ", "); *s; s += strspn(s, ", ")) { const char *name; uint64_t header; ovs_be64 nw_header; int name_len; size_t n; name = s; name_len = strcspn(s, "("); if (s[name_len] != '(') { ovs_fatal(0, "%s: missing ( at end of nx_match", full_s); } header = parse_nxm_field_name(name, name_len); if (!header) { ovs_fatal(0, "%s: unknown field `%.*s'", full_s, name_len, s); } s += name_len + 1; b->header = ofpbuf_put_uninit(b, nxm_header_len(header)); s = ofpbuf_put_hex(b, s, &n); if (n != nxm_field_bytes(header)) { const struct mf_field *field = mf_from_oxm_header(header, NULL); if (field && field->variable_len) { if (n <= field->n_bytes) { int len = (nxm_hasmask(header) ? n * 2 : n) + nxm_experimenter_len(header); header = NXM_HEADER(nxm_vendor(header), nxm_class(header), nxm_field(header), nxm_hasmask(header) ? 1 : 0, len); } else { ovs_fatal(0, "expected to read at most %d bytes but got " "%"PRIuSIZE, field->n_bytes, n); } } else { ovs_fatal(0, "expected to read %d bytes but got %"PRIuSIZE, nxm_field_bytes(header), n); } } nw_header = htonll(header); memcpy(b->header, &nw_header, nxm_header_len(header)); if (nxm_hasmask(header)) { s += strspn(s, " "); if (*s != '/') { ovs_fatal(0, "%s: missing / in masked field %.*s", full_s, name_len, name); } s = ofpbuf_put_hex(b, s + 1, &n); if (n != nxm_field_bytes(header)) { ovs_fatal(0, "%.2s: hex digits expected", s); } } s += strspn(s, " "); if (*s != ')') { ovs_fatal(0, "%s: missing ) following field %.*s", full_s, name_len, name); } s++; } return b->size - start_len; } int nx_match_from_string(const char *s, struct ofpbuf *b) { int match_len = nx_match_from_string_raw(s, b); ofpbuf_put_zeros(b, PAD_SIZE(match_len, 8)); return match_len; } int oxm_match_from_string(const char *s, struct ofpbuf *b) { int match_len; struct ofp11_match_header *omh; size_t start_len = b->size; ofpbuf_put_uninit(b, sizeof *omh); match_len = nx_match_from_string_raw(s, b) + sizeof *omh; ofpbuf_put_zeros(b, PAD_SIZE(match_len, 8)); omh = ofpbuf_at(b, start_len, sizeof *omh); omh->type = htons(OFPMT_OXM); omh->length = htons(match_len); return match_len; } /* Parses 's' as a "move" action, in the form described in ovs-ofctl(8), into * '*move'. * * Returns NULL if successful, otherwise a malloc()'d string describing the * error. The caller is responsible for freeing the returned string. */ char * OVS_WARN_UNUSED_RESULT nxm_parse_reg_move(struct ofpact_reg_move *move, const char *s) { const char *full_s = s; char *error; error = mf_parse_subfield__(&move->src, &s); if (error) { return error; } if (strncmp(s, "->", 2)) { return xasprintf("%s: missing `->' following source", full_s); } s += 2; error = mf_parse_subfield(&move->dst, s); if (error) { return error; } if (move->src.n_bits != move->dst.n_bits) { return xasprintf("%s: source field is %d bits wide but destination is " "%d bits wide", full_s, move->src.n_bits, move->dst.n_bits); } return NULL; } /* nxm_format_reg_move(). */ void nxm_format_reg_move(const struct ofpact_reg_move *move, struct ds *s) { ds_put_format(s, "%smove:%s", colors.special, colors.end); mf_format_subfield(&move->src, s); ds_put_format(s, "%s->%s", colors.special, colors.end); mf_format_subfield(&move->dst, s); } enum ofperr nxm_reg_move_check(const struct ofpact_reg_move *move, const struct match *match) { enum ofperr error; error = mf_check_src(&move->src, match); if (error) { return error; } return mf_check_dst(&move->dst, match); } /* nxm_execute_reg_move(). */ void nxm_reg_load(const struct mf_subfield *dst, uint64_t src_data, struct flow *flow, struct flow_wildcards *wc) { union mf_subvalue src_subvalue; union mf_subvalue mask_value; ovs_be64 src_data_be = htonll(src_data); memset(&mask_value, 0xff, sizeof mask_value); mf_write_subfield_flow(dst, &mask_value, &wc->masks); bitwise_copy(&src_data_be, sizeof src_data_be, 0, &src_subvalue, sizeof src_subvalue, 0, sizeof src_data_be * 8); mf_write_subfield_flow(dst, &src_subvalue, flow); } /* nxm_parse_stack_action, works for both push() and pop(). */ /* Parses 's' as a "push" or "pop" action, in the form described in * ovs-ofctl(8), into '*stack_action'. * * Returns NULL if successful, otherwise a malloc()'d string describing the * error. The caller is responsible for freeing the returned string. */ char * OVS_WARN_UNUSED_RESULT nxm_parse_stack_action(struct ofpact_stack *stack_action, const char *s) { char *error; error = mf_parse_subfield__(&stack_action->subfield, &s); if (error) { return error; } if (*s != '\0') { return xasprintf("%s: trailing garbage following push or pop", s); } return NULL; } void nxm_format_stack_push(const struct ofpact_stack *push, struct ds *s) { ds_put_format(s, "%spush:%s", colors.param, colors.end); mf_format_subfield(&push->subfield, s); } void nxm_format_stack_pop(const struct ofpact_stack *pop, struct ds *s) { ds_put_format(s, "%spop:%s", colors.param, colors.end); mf_format_subfield(&pop->subfield, s); } enum ofperr nxm_stack_push_check(const struct ofpact_stack *push, const struct match *match) { return mf_check_src(&push->subfield, match); } enum ofperr nxm_stack_pop_check(const struct ofpact_stack *pop, const struct match *match) { return mf_check_dst(&pop->subfield, match); } /* nxm_execute_stack_push(), nxm_execute_stack_pop(). * * A stack is an ofpbuf with 'data' pointing to the bottom of the stack and * 'size' indexing the top of the stack. Each value of some byte length is * stored to the stack immediately followed by the length of the value as an * unsigned byte. This way a POP operation can first read the length byte, and * then the appropriate number of bytes from the stack. This also means that * it is only possible to traverse the stack from top to bottom. It is * possible, however, to push values also to the bottom of the stack, which is * useful when a stack has been serialized to a wire format in reverse order * (topmost value first). */ /* Push value 'v' of length 'bytes' to the top of 'stack'. */ void nx_stack_push(struct ofpbuf *stack, const void *v, uint8_t bytes) { ofpbuf_put(stack, v, bytes); ofpbuf_put(stack, &bytes, sizeof bytes); } /* Push value 'v' of length 'bytes' to the bottom of 'stack'. */ void nx_stack_push_bottom(struct ofpbuf *stack, const void *v, uint8_t bytes) { ofpbuf_push(stack, &bytes, sizeof bytes); ofpbuf_push(stack, v, bytes); } /* Pop the topmost value from 'stack', returning a pointer to the value in the * stack and the length of the value in '*bytes'. In case of underflow a NULL * is returned and length is returned as zero via '*bytes'. */ void * nx_stack_pop(struct ofpbuf *stack, uint8_t *bytes) { if (!stack->size) { *bytes = 0; return NULL; } stack->size -= sizeof *bytes; memcpy(bytes, ofpbuf_tail(stack), sizeof *bytes); ovs_assert(stack->size >= *bytes); stack->size -= *bytes; return ofpbuf_tail(stack); } void nxm_execute_stack_push(const struct ofpact_stack *push, const struct flow *flow, struct flow_wildcards *wc, struct ofpbuf *stack) { union mf_subvalue dst_value; mf_write_subfield_flow(&push->subfield, (union mf_subvalue *)&exact_match_mask, &wc->masks); mf_read_subfield(&push->subfield, flow, &dst_value); uint8_t bytes = DIV_ROUND_UP(push->subfield.n_bits, 8); nx_stack_push(stack, &dst_value.u8[sizeof dst_value - bytes], bytes); } bool nxm_execute_stack_pop(const struct ofpact_stack *pop, struct flow *flow, struct flow_wildcards *wc, struct ofpbuf *stack) { uint8_t src_bytes; const void *src = nx_stack_pop(stack, &src_bytes); if (src) { union mf_subvalue src_value; uint8_t dst_bytes = DIV_ROUND_UP(pop->subfield.n_bits, 8); if (src_bytes < dst_bytes) { memset(&src_value.u8[sizeof src_value - dst_bytes], 0, dst_bytes - src_bytes); } memcpy(&src_value.u8[sizeof src_value - src_bytes], src, src_bytes); mf_write_subfield_flow(&pop->subfield, (union mf_subvalue *)&exact_match_mask, &wc->masks); mf_write_subfield_flow(&pop->subfield, &src_value, flow); return true; } else { /* Attempted to pop from an empty stack. */ return false; } } /* Formats 'sf' into 's' in a format normally acceptable to * mf_parse_subfield(). (It won't be acceptable if sf->field is NULL or if * sf->field has no NXM name.) */ void mf_format_subfield(const struct mf_subfield *sf, struct ds *s) { if (!sf->field) { ds_put_cstr(s, ""); } else { const struct nxm_field *f = nxm_field_by_mf_id(sf->field->id, 0); ds_put_cstr(s, f ? f->name : sf->field->name); } if (sf->field && sf->ofs == 0 && sf->n_bits == sf->field->n_bits) { ds_put_cstr(s, "[]"); } else if (sf->n_bits == 1) { ds_put_format(s, "[%d]", sf->ofs); } else { ds_put_format(s, "[%d..%d]", sf->ofs, sf->ofs + sf->n_bits - 1); } } static const struct nxm_field * mf_parse_subfield_name(const char *name, int name_len, bool *wild) { *wild = name_len > 2 && !memcmp(&name[name_len - 2], "_W", 2); if (*wild) { name_len -= 2; } return nxm_field_by_name(name, name_len); } /* Parses a subfield from the beginning of '*sp' into 'sf'. If successful, * returns NULL and advances '*sp' to the first byte following the parsed * string. On failure, returns a malloc()'d error message, does not modify * '*sp', and does not properly initialize 'sf'. * * The syntax parsed from '*sp' takes the form "header[start..end]" where * 'header' is the name of an NXM field and 'start' and 'end' are (inclusive) * bit indexes. "..end" may be omitted to indicate a single bit. "start..end" * may both be omitted (the [] are still required) to indicate an entire * field. */ char * OVS_WARN_UNUSED_RESULT mf_parse_subfield__(struct mf_subfield *sf, const char **sp) { const struct mf_field *field = NULL; const struct nxm_field *f; const char *name; int start, end; const char *s; int name_len; bool wild; s = *sp; name = s; name_len = strcspn(s, "[-"); f = mf_parse_subfield_name(name, name_len, &wild); field = f ? mf_from_id(f->id) : mf_from_name_len(name, name_len); if (!field) { return xasprintf("%s: unknown field `%.*s'", *sp, name_len, s); } s += name_len; /* Assume full field. */ start = 0; end = field->n_bits - 1; if (*s == '[') { if (!strncmp(s, "[]", 2)) { /* Nothing to do. */ } else if (ovs_scan(s, "[%d..%d]", &start, &end)) { /* Nothing to do. */ } else if (ovs_scan(s, "[%d]", &start)) { end = start; } else { return xasprintf("%s: syntax error expecting [] or [] or " "[..]", *sp); } s = strchr(s, ']') + 1; } if (start > end) { return xasprintf("%s: starting bit %d is after ending bit %d", *sp, start, end); } else if (start >= field->n_bits) { return xasprintf("%s: starting bit %d is not valid because field is " "only %d bits wide", *sp, start, field->n_bits); } else if (end >= field->n_bits){ return xasprintf("%s: ending bit %d is not valid because field is " "only %d bits wide", *sp, end, field->n_bits); } sf->field = field; sf->ofs = start; sf->n_bits = end - start + 1; *sp = s; return NULL; } /* Parses a subfield from the entirety of 's' into 'sf'. Returns NULL if * successful, otherwise a malloc()'d string describing the error. The caller * is responsible for freeing the returned string. * * The syntax parsed from 's' takes the form "header[start..end]" where * 'header' is the name of an NXM field and 'start' and 'end' are (inclusive) * bit indexes. "..end" may be omitted to indicate a single bit. "start..end" * may both be omitted (the [] are still required) to indicate an entire * field. */ char * OVS_WARN_UNUSED_RESULT mf_parse_subfield(struct mf_subfield *sf, const char *s) { char *error = mf_parse_subfield__(sf, &s); if (!error && s[0]) { error = xstrdup("unexpected input following field syntax"); } return error; } /* Returns an bitmap in which each bit corresponds to the like-numbered field * in the OFPXMC12_OPENFLOW_BASIC OXM class, in which the bit values are taken * from the 'fields' bitmap. Only fields defined in OpenFlow 'version' are * considered. * * This is useful for encoding OpenFlow 1.2 table stats messages. */ ovs_be64 oxm_bitmap_from_mf_bitmap(const struct mf_bitmap *fields, enum ofp_version version) { uint64_t oxm_bitmap = 0; int i; BITMAP_FOR_EACH_1 (i, MFF_N_IDS, fields->bm) { uint64_t oxm = mf_oxm_header(i, version); uint32_t class = nxm_class(oxm); int field = nxm_field(oxm); if (class == OFPXMC12_OPENFLOW_BASIC && field < 64) { oxm_bitmap |= UINT64_C(1) << field; } } return htonll(oxm_bitmap); } /* Opposite conversion from oxm_bitmap_from_mf_bitmap(). * * This is useful for decoding OpenFlow 1.2 table stats messages. */ struct mf_bitmap oxm_bitmap_to_mf_bitmap(ovs_be64 oxm_bitmap, enum ofp_version version) { struct mf_bitmap fields = MF_BITMAP_INITIALIZER; for (enum mf_field_id id = 0; id < MFF_N_IDS; id++) { uint64_t oxm = mf_oxm_header(id, version); if (oxm && version >= nxm_field_by_header(oxm)->version) { uint32_t class = nxm_class(oxm); int field = nxm_field(oxm); if (class == OFPXMC12_OPENFLOW_BASIC && field < 64 && oxm_bitmap & htonll(UINT64_C(1) << field)) { bitmap_set1(fields.bm, id); } } } return fields; } /* Returns a bitmap of fields that can be encoded in OXM and that can be * modified with a "set_field" action. */ struct mf_bitmap oxm_writable_fields(void) { struct mf_bitmap b = MF_BITMAP_INITIALIZER; int i; for (i = 0; i < MFF_N_IDS; i++) { if (mf_oxm_header(i, 0) && mf_from_id(i)->writable) { bitmap_set1(b.bm, i); } } return b; } /* Returns a bitmap of fields that can be encoded in OXM and that can be * matched in a flow table. */ struct mf_bitmap oxm_matchable_fields(void) { struct mf_bitmap b = MF_BITMAP_INITIALIZER; int i; for (i = 0; i < MFF_N_IDS; i++) { if (mf_oxm_header(i, 0)) { bitmap_set1(b.bm, i); } } return b; } /* Returns a bitmap of fields that can be encoded in OXM and that can be * matched in a flow table with an arbitrary bitmask. */ struct mf_bitmap oxm_maskable_fields(void) { struct mf_bitmap b = MF_BITMAP_INITIALIZER; int i; for (i = 0; i < MFF_N_IDS; i++) { if (mf_oxm_header(i, 0) && mf_from_id(i)->maskable == MFM_FULLY) { bitmap_set1(b.bm, i); } } return b; } struct nxm_field_index { struct hmap_node header_node; /* In nxm_header_map. */ struct hmap_node name_node; /* In nxm_name_map. */ struct ovs_list mf_node; /* In mf_mf_map[nf.id]. */ const struct nxm_field nf; }; #include "nx-match.inc" static struct hmap nxm_header_map; static struct hmap nxm_name_map; static struct ovs_list nxm_mf_map[MFF_N_IDS]; static void nxm_init(void) { static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER; if (ovsthread_once_start(&once)) { hmap_init(&nxm_header_map); hmap_init(&nxm_name_map); for (int i = 0; i < MFF_N_IDS; i++) { ovs_list_init(&nxm_mf_map[i]); } for (struct nxm_field_index *nfi = all_nxm_fields; nfi < &all_nxm_fields[ARRAY_SIZE(all_nxm_fields)]; nfi++) { hmap_insert(&nxm_header_map, &nfi->header_node, hash_uint64(nxm_no_len(nfi->nf.header))); hmap_insert(&nxm_name_map, &nfi->name_node, hash_string(nfi->nf.name, 0)); ovs_list_push_back(&nxm_mf_map[nfi->nf.id], &nfi->mf_node); } ovsthread_once_done(&once); } } static const struct nxm_field * nxm_field_by_header(uint64_t header) { const struct nxm_field_index *nfi; uint64_t header_no_len; nxm_init(); if (nxm_hasmask(header)) { header = nxm_make_exact_header(header); } header_no_len = nxm_no_len(header); HMAP_FOR_EACH_IN_BUCKET (nfi, header_node, hash_uint64(header_no_len), &nxm_header_map) { if (header_no_len == nxm_no_len(nfi->nf.header)) { if (nxm_length(header) == nxm_length(nfi->nf.header) || mf_from_id(nfi->nf.id)->variable_len) { return &nfi->nf; } else { return NULL; } } } return NULL; } static const struct nxm_field * nxm_field_by_name(const char *name, size_t len) { const struct nxm_field_index *nfi; nxm_init(); HMAP_FOR_EACH_WITH_HASH (nfi, name_node, hash_bytes(name, len, 0), &nxm_name_map) { if (strlen(nfi->nf.name) == len && !memcmp(nfi->nf.name, name, len)) { return &nfi->nf; } } return NULL; } static const struct nxm_field * nxm_field_by_mf_id(enum mf_field_id id, enum ofp_version version) { const struct nxm_field_index *nfi; const struct nxm_field *f; nxm_init(); f = NULL; LIST_FOR_EACH (nfi, mf_node, &nxm_mf_map[id]) { if (!f || version >= nfi->nf.version) { f = &nfi->nf; } } return f; }