lib/ofp-errors.c

   1 /*
   2  * Copyright (c) 2012, 2013, 2014 Nicira, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <config.h>
  18 #include "ofp-errors.h"
  19 #include <errno.h>
  20 #include "byte-order.h"
  21 #include "dynamic-string.h"
  22 #include "ofp-msgs.h"
  23 #include "ofp-util.h"
  24 #include "ofpbuf.h"
  25 #include "openflow/openflow.h"
  26 #include "openvswitch/vlog.h"
  27
  28 VLOG_DEFINE_THIS_MODULE(ofp_errors);
  29
  30 struct triplet {
  31     uint32_t vendor;
  32     int type, code;
  33 };
  34
  35 #include "ofp-errors.inc"
  36
  37 /* Returns an ofperr_domain that corresponds to the OpenFlow version number
  38  * 'version' (one of the possible values of struct ofp_header's 'version'
  39  * member).  Returns NULL if the version isn't defined or isn't understood by
  40  * OVS. */
  41 static const struct ofperr_domain *
  42 ofperr_domain_from_version(enum ofp_version version)
  43 {
  44     switch (version) {
  45     case OFP10_VERSION:
  46         return &ofperr_of10;
  47     case OFP11_VERSION:
  48         return &ofperr_of11;
  49     case OFP12_VERSION:
  50         return &ofperr_of12;
  51     case OFP13_VERSION:
  52         return &ofperr_of13;
  53     case OFP14_VERSION:
  54         return &ofperr_of14;
  55     case OFP15_VERSION:
  56         return &ofperr_of15;
  57     default:
  58         return NULL;
  59     }
  60 }
  61
  62 /* Returns the name (e.g. "OpenFlow 1.0") of OpenFlow version 'version'. */
  63 const char *
  64 ofperr_domain_get_name(enum ofp_version version)
  65 {
  66     const struct ofperr_domain *domain = ofperr_domain_from_version(version);
  67     return domain ? domain->name : NULL;
  68 }
  69
  70 /* Returns true if 'error' is a valid OFPERR_* value, false otherwise. */
  71 bool
  72 ofperr_is_valid(enum ofperr error)
  73 {
  74     return error >= OFPERR_OFS && error < OFPERR_OFS + OFPERR_N_ERRORS;
  75 }
  76
  77 /* Returns the OFPERR_* value that corresponds to 'type' and 'code' within
  78  * 'version', or 0 if either no such OFPERR_* value exists or 'version' is
  79  * unknown. */
  80 static enum ofperr
  81 ofperr_decode(enum ofp_version version,
  82               uint32_t vendor, uint16_t type, uint16_t code)
  83 {
  84     const struct ofperr_domain *domain = ofperr_domain_from_version(version);
  85     return domain ? domain->decode(vendor, type, code) : 0;
  86 }
  87
  88 /* Returns the name of 'error', e.g. "OFPBRC_BAD_TYPE" if 'error' is
  89  * OFPBRC_BAD_TYPE, or "<invalid>" if 'error' is not a valid OFPERR_* value.
  90  *
  91  * Consider ofperr_to_string() instead, if the error code might be an errno
  92  * value. */
  93 const char *
  94 ofperr_get_name(enum ofperr error)
  95 {
  96     return (ofperr_is_valid(error)
  97             ? error_names[error - OFPERR_OFS]
  98             : "<invalid>");
  99 }
 100
 101 /* Returns the OFPERR_* value that corresponds for 'name', 0 if none exists.
 102  * For example, returns OFPERR_OFPHFC_INCOMPATIBLE if 'name' is
 103  * "OFPHFC_INCOMPATIBLE".
 104  *
 105  * This is probably useful only for debugging and testing. */
 106 enum ofperr
 107 ofperr_from_name(const char *name)
 108 {
 109     int i;
 110
 111     for (i = 0; i < OFPERR_N_ERRORS; i++) {
 112         if (!strcmp(name, error_names[i])) {
 113             return i + OFPERR_OFS;
 114         }
 115     }
 116     return 0;
 117 }
 118
 119 /* Returns an extended description name of 'error', e.g. "ofp_header.type not
 120  * supported." if 'error' is OFPBRC_BAD_TYPE, or "<invalid>" if 'error' is not
 121  * a valid OFPERR_* value. */
 122 const char *
 123 ofperr_get_description(enum ofperr error)
 124 {
 125     return (ofperr_is_valid(error)
 126             ? error_comments[error - OFPERR_OFS]
 127             : "<invalid>");
 128 }
 129
 130 static const struct triplet *
 131 ofperr_get_triplet__(enum ofperr error, const struct ofperr_domain *domain)
 132 {
 133     size_t ofs = error - OFPERR_OFS;
 134
 135     ovs_assert(ofperr_is_valid(error));
 136     return &domain->errors[ofs];
 137 }
 138
 139 static struct ofpbuf *
 140 ofperr_encode_msg__(enum ofperr error, enum ofp_version ofp_version,
 141                     ovs_be32 xid, const void *data, size_t data_len)
 142 {
 143     static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
 144     const struct ofperr_domain *domain;
 145     const struct triplet *triplet;
 146     struct ofp_error_msg *oem;
 147     struct ofpbuf *buf;
 148
 149     /* Get the error domain for 'ofp_version', or fall back to OF1.0. */
 150     domain = ofperr_domain_from_version(ofp_version);
 151     if (!domain) {
 152         VLOG_ERR_RL(&rl, "cannot encode error for unknown OpenFlow "
 153                     "version 0x%02x", ofp_version);
 154         domain = &ofperr_of10;
 155     }
 156
 157     /* Make sure 'error' is valid in 'domain', or use a fallback error. */
 158     if (!ofperr_is_valid(error)) {
 159         /* 'error' seems likely to be a system errno value. */
 160         VLOG_ERR_RL(&rl, "invalid OpenFlow error code %d (%s)",
 161                     error, ovs_strerror(error));
 162         error = OFPERR_NXBRC_UNENCODABLE_ERROR;
 163     } else if (domain->errors[error - OFPERR_OFS].code < 0) {
 164         VLOG_ERR_RL(&rl, "cannot encode %s for %s",
 165                     ofperr_get_name(error), domain->name);
 166         error = OFPERR_NXBRC_UNENCODABLE_ERROR;
 167     }
 168
 169     triplet = ofperr_get_triplet__(error, domain);
 170     if (!triplet->vendor) {
 171         buf = ofpraw_alloc_xid(OFPRAW_OFPT_ERROR, domain->version, xid,
 172                                sizeof *oem + data_len);
 173
 174         oem = ofpbuf_put_uninit(buf, sizeof *oem);
 175         oem->type = htons(triplet->type);
 176         oem->code = htons(triplet->code);
 177     } else if (ofp_version <= OFP11_VERSION) {
 178         struct nx_vendor_error *nve;
 179
 180         buf = ofpraw_alloc_xid(OFPRAW_OFPT_ERROR, domain->version, xid,
 181                                sizeof *oem + sizeof *nve + data_len);
 182
 183         oem = ofpbuf_put_uninit(buf, sizeof *oem);
 184         oem->type = htons(NXET_VENDOR);
 185         oem->code = htons(NXVC_VENDOR_ERROR);
 186
 187         nve = ofpbuf_put_uninit(buf, sizeof *nve);
 188         nve->vendor = htonl(triplet->vendor);
 189         nve->type = htons(triplet->type);
 190         nve->code = htons(triplet->code);
 191     } else {
 192         ovs_be32 vendor = htonl(triplet->vendor);
 193
 194         buf = ofpraw_alloc_xid(OFPRAW_OFPT_ERROR, domain->version, xid,
 195                                sizeof *oem + sizeof(uint32_t) + data_len);
 196
 197         oem = ofpbuf_put_uninit(buf, sizeof *oem);
 198         oem->type = htons(OFPET12_EXPERIMENTER);
 199         oem->code = htons(triplet->type);
 200         ofpbuf_put(buf, &vendor, sizeof vendor);
 201     }
 202
 203     ofpbuf_put(buf, data, data_len);
 204     ofpmsg_update_length(buf);
 205
 206     return buf;
 207 }
 208
 209 /* Creates and returns an OpenFlow message of type OFPT_ERROR that conveys the
 210  * given 'error'.
 211  *
 212  * 'oh->version' determines the OpenFlow version of the error reply.
 213  * 'oh->xid' determines the xid of the error reply.
 214  * The error reply will contain an initial subsequence of 'oh', up to
 215  * 'oh->length' or 64 bytes, whichever is shorter.
 216  *
 217  * This function isn't appropriate for encoding OFPET_HELLO_FAILED error
 218  * messages.  Use ofperr_encode_hello() instead. */
 219 struct ofpbuf *
 220 ofperr_encode_reply(enum ofperr error, const struct ofp_header *oh)
 221 {
 222     uint16_t len = ntohs(oh->length);
 223
 224     return ofperr_encode_msg__(error, oh->version, oh->xid, oh, MIN(len, 64));
 225 }
 226
 227 /* Creates and returns an OpenFlow message of type OFPT_ERROR that conveys the
 228  * given 'error', in the error domain 'domain'.  The error message will include
 229  * the additional null-terminated text string 's'.
 230  *
 231  * If 'version' is an unknown version then OFP10_VERSION is used.
 232  * OFPET_HELLO_FAILED error messages are supposed to be backward-compatible,
 233  * so in theory this should work. */
 234 struct ofpbuf *
 235 ofperr_encode_hello(enum ofperr error, enum ofp_version ofp_version,
 236                     const char *s)
 237 {
 238     return ofperr_encode_msg__(error, ofp_version, htonl(0), s, strlen(s));
 239 }
 240
 241 int
 242 ofperr_get_vendor(enum ofperr error, enum ofp_version version)
 243 {
 244     const struct ofperr_domain *domain = ofperr_domain_from_version(version);
 245     return domain ? ofperr_get_triplet__(error, domain)->vendor : -1;
 246 }
 247
 248 /* Returns the value that would go into an OFPT_ERROR message's 'type' for
 249  * encoding 'error' in 'domain'.  Returns -1 if 'error' is not encodable in
 250  * 'version' or 'version' is unknown.
 251  *
 252  * 'error' must be a valid OFPERR_* code, as checked by ofperr_is_valid(). */
 253 int
 254 ofperr_get_type(enum ofperr error, enum ofp_version version)
 255 {
 256     const struct ofperr_domain *domain = ofperr_domain_from_version(version);
 257     return domain ? ofperr_get_triplet__(error, domain)->type : -1;
 258 }
 259
 260 /* Returns the value that would go into an OFPT_ERROR message's 'code' for
 261  * encoding 'error' in 'domain'.  Returns -1 if 'error' is not encodable in
 262  * 'version', 'version' is unknown or if 'error' represents a category
 263  * rather than a specific error.
 264  *
 265  *
 266  * 'error' must be a valid OFPERR_* code, as checked by ofperr_is_valid(). */
 267 int
 268 ofperr_get_code(enum ofperr error, enum ofp_version version)
 269 {
 270     const struct ofperr_domain *domain = ofperr_domain_from_version(version);
 271     return domain ? ofperr_get_triplet__(error, domain)->code : -1;
 272 }
 273
 274 /* Tries to decode 'oh', which should be an OpenFlow OFPT_ERROR message.
 275  * Returns an OFPERR_* constant on success, 0 on failure.
 276  *
 277  * If 'payload' is nonnull, on success '*payload' is initialized with a copy of
 278  * the error's payload (copying is required because the payload is not properly
 279  * aligned).  The caller must free the payload (with ofpbuf_uninit()) when it
 280  * is no longer needed.  On failure, '*payload' is cleared. */
 281 enum ofperr
 282 ofperr_decode_msg(const struct ofp_header *oh, struct ofpbuf *payload)
 283 {
 284     const struct ofp_error_msg *oem;
 285     enum ofpraw raw;
 286     uint16_t type, code;
 287     enum ofperr error;
 288     uint32_t vendor;
 289     struct ofpbuf b;
 290
 291     if (payload) {
 292         memset(payload, 0, sizeof *payload);
 293     }
 294
 295     /* Pull off the error message. */
 296     ofpbuf_use_const(&b, oh, ntohs(oh->length));
 297     error = ofpraw_pull(&raw, &b);
 298     if (error) {
 299         return 0;
 300     }
 301     oem = ofpbuf_pull(&b, sizeof *oem);
 302
 303     /* Get the error type and code. */
 304     vendor = 0;
 305     type = ntohs(oem->type);
 306     code = ntohs(oem->code);
 307     if (type == NXET_VENDOR && code == NXVC_VENDOR_ERROR) {
 308         const struct nx_vendor_error *nve = ofpbuf_try_pull(&b, sizeof *nve);
 309         if (!nve) {
 310             return 0;
 311         }
 312
 313         vendor = ntohl(nve->vendor);
 314         type = ntohs(nve->type);
 315         code = ntohs(nve->code);
 316     } else if (type == OFPET12_EXPERIMENTER) {
 317         const ovs_be32 *vendorp = ofpbuf_try_pull(&b, sizeof *vendorp);
 318         if (!vendorp) {
 319             return 0;
 320         }
 321
 322         vendor = ntohl(*vendorp);
 323         type = code;
 324         code = 0;
 325     }
 326
 327     /* Translate the error type and code into an ofperr. */
 328     error = ofperr_decode(oh->version, vendor, type, code);
 329     if (error && payload) {
 330         ofpbuf_init(payload, b.size);
 331         ofpbuf_push(payload, b.data, b.size);
 332     }
 333     return error;
 334 }
 335
 336 /* If 'error' is a valid OFPERR_* value, returns its name
 337  * (e.g. "OFPBRC_BAD_TYPE" for OFPBRC_BAD_TYPE).  Otherwise, assumes that
 338  * 'error' is a positive errno value and returns what ovs_strerror() produces
 339  * for 'error'.  */
 340 const char *
 341 ofperr_to_string(enum ofperr error)
 342 {
 343     return (ofperr_is_valid(error)
 344             ? ofperr_get_name(error)
 345             : ovs_strerror(error));
 346 }