lib/ofp-errors.c

   1 /*
   2  * Copyright (c) 2012, 2013, 2014, 2015, 2016 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 <errno.h>
  19 #include "byte-order.h"
  20 #include "openflow/openflow.h"
  21 #include "openvswitch/dynamic-string.h"
  22 #include "openvswitch/ofp-errors.h"
  23 #include "openvswitch/ofp-msgs.h"
  24 #include "openvswitch/ofp-util.h"
  25 #include "openvswitch/ofpbuf.h"
  26 #include "openvswitch/vlog.h"
  27 #include "util.h"
  28
  29 VLOG_DEFINE_THIS_MODULE(ofp_errors);
  30
  31 struct triplet {
  32     uint32_t vendor;
  33     int type, code;
  34 };
  35
  36 #include "ofp-errors.inc"
  37
  38 /* Returns an ofperr_domain that corresponds to the OpenFlow version number
  39  * 'version' (one of the possible values of struct ofp_header's 'version'
  40  * member).  Returns NULL if the version isn't defined or isn't understood by
  41  * OVS. */
  42 static const struct ofperr_domain *
  43 ofperr_domain_from_version(enum ofp_version version)
  44 {
  45     switch (version) {
  46     case OFP10_VERSION:
  47         return &ofperr_of10;
  48     case OFP11_VERSION:
  49         return &ofperr_of11;
  50     case OFP12_VERSION:
  51         return &ofperr_of12;
  52     case OFP13_VERSION:
  53         return &ofperr_of13;
  54     case OFP14_VERSION:
  55         return &ofperr_of14;
  56     case OFP15_VERSION:
  57         return &ofperr_of15;
  58     case OFP16_VERSION:
  59         return &ofperr_of16;
  60     default:
  61         return NULL;
  62     }
  63 }
  64
  65 /* Returns the name (e.g. "OpenFlow 1.0") of OpenFlow version 'version'. */
  66 const char *
  67 ofperr_domain_get_name(enum ofp_version version)
  68 {
  69     const struct ofperr_domain *domain = ofperr_domain_from_version(version);
  70     return domain ? domain->name : NULL;
  71 }
  72
  73 /* Returns true if 'error' is a valid OFPERR_* value, false otherwise. */
  74 bool
  75 ofperr_is_valid(enum ofperr error)
  76 {
  77     return error >= OFPERR_OFS && error < OFPERR_OFS + OFPERR_N_ERRORS;
  78 }
  79
  80 /* Returns the OFPERR_* value that corresponds to 'type' and 'code' within
  81  * 'version', or 0 if either no such OFPERR_* value exists or 'version' is
  82  * unknown. */
  83 static enum ofperr
  84 ofperr_decode(enum ofp_version version,
  85               uint32_t vendor, uint16_t type, uint16_t code)
  86 {
  87     const struct ofperr_domain *domain = ofperr_domain_from_version(version);
  88     return domain ? domain->decode(vendor, type, code) : 0;
  89 }
  90
  91 /* Returns the name of 'error', e.g. "OFPBRC_BAD_TYPE" if 'error' is
  92  * OFPBRC_BAD_TYPE, or "<invalid>" if 'error' is not a valid OFPERR_* value.
  93  *
  94  * Consider ofperr_to_string() instead, if the error code might be an errno
  95  * value. */
  96 const char *
  97 ofperr_get_name(enum ofperr error)
  98 {
  99     return (ofperr_is_valid(error)
 100             ? error_names[error - OFPERR_OFS]
 101             : "<invalid>");
 102 }
 103
 104 /* Returns the OFPERR_* value that corresponds for 'name', 0 if none exists.
 105  * For example, returns OFPERR_OFPHFC_INCOMPATIBLE if 'name' is
 106  * "OFPHFC_INCOMPATIBLE".
 107  *
 108  * This is probably useful only for debugging and testing. */
 109 enum ofperr
 110 ofperr_from_name(const char *name)
 111 {
 112     int i;
 113
 114     for (i = 0; i < OFPERR_N_ERRORS; i++) {
 115         if (!strcmp(name, error_names[i])) {
 116             return i + OFPERR_OFS;
 117         }
 118     }
 119     return 0;
 120 }
 121
 122 /* Returns an extended description name of 'error', e.g. "ofp_header.type not
 123  * supported." if 'error' is OFPBRC_BAD_TYPE, or "<invalid>" if 'error' is not
 124  * a valid OFPERR_* value. */
 125 const char *
 126 ofperr_get_description(enum ofperr error)
 127 {
 128     return (ofperr_is_valid(error)
 129             ? error_comments[error - OFPERR_OFS]
 130             : "<invalid>");
 131 }
 132
 133 static const struct triplet *
 134 ofperr_get_triplet__(enum ofperr error, const struct ofperr_domain *domain)
 135 {
 136     size_t ofs = error - OFPERR_OFS;
 137
 138     ovs_assert(ofperr_is_valid(error));
 139     return &domain->errors[ofs];
 140 }
 141
 142 static struct ofpbuf *
 143 ofperr_encode_msg__(enum ofperr error, enum ofp_version ofp_version,
 144                     ovs_be32 xid, const void *data, size_t data_len)
 145 {
 146     static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
 147     const struct ofperr_domain *domain;
 148     const struct triplet *triplet;
 149     struct ofp_error_msg *oem;
 150     struct ofpbuf *buf;
 151
 152     /* Get the error domain for 'ofp_version', or fall back to OF1.0. */
 153     domain = ofperr_domain_from_version(ofp_version);
 154     if (!domain) {
 155         VLOG_ERR_RL(&rl, "cannot encode error for unknown OpenFlow "
 156                     "version 0x%02x", ofp_version);
 157         domain = &ofperr_of10;
 158     }
 159
 160     /* Make sure 'error' is valid in 'domain', or use a fallback error. */
 161     if (!ofperr_is_valid(error)) {
 162         /* 'error' seems likely to be a system errno value. */
 163         VLOG_ERR_RL(&rl, "invalid OpenFlow error code %d (%s)",
 164                     error, ovs_strerror(error));
 165         error = OFPERR_NXBRC_UNENCODABLE_ERROR;
 166     } else if (domain->errors[error - OFPERR_OFS].code < 0) {
 167         VLOG_ERR_RL(&rl, "cannot encode %s for %s",
 168                     ofperr_get_name(error), domain->name);
 169         error = OFPERR_NXBRC_UNENCODABLE_ERROR;
 170     }
 171
 172     triplet = ofperr_get_triplet__(error, domain);
 173     if (!triplet->vendor) {
 174         buf = ofpraw_alloc_xid(OFPRAW_OFPT_ERROR, domain->version, xid,
 175                                sizeof *oem + data_len);
 176
 177         oem = ofpbuf_put_uninit(buf, sizeof *oem);
 178         oem->type = htons(triplet->type);
 179         oem->code = htons(triplet->code);
 180     } else if (ofp_version <= OFP11_VERSION) {
 181         struct nx_vendor_error *nve;
 182
 183         buf = ofpraw_alloc_xid(OFPRAW_OFPT_ERROR, domain->version, xid,
 184                                sizeof *oem + sizeof *nve + data_len);
 185
 186         oem = ofpbuf_put_uninit(buf, sizeof *oem);
 187         oem->type = htons(NXET_VENDOR);
 188         oem->code = htons(NXVC_VENDOR_ERROR);
 189
 190         nve = ofpbuf_put_uninit(buf, sizeof *nve);
 191         nve->vendor = htonl(triplet->vendor);
 192         nve->type = htons(triplet->type);
 193         nve->code = htons(triplet->code);
 194     } else {
 195         ovs_be32 vendor = htonl(triplet->vendor);
 196
 197         buf = ofpraw_alloc_xid(OFPRAW_OFPT_ERROR, domain->version, xid,
 198                                sizeof *oem + sizeof(uint32_t) + data_len);
 199
 200         oem = ofpbuf_put_uninit(buf, sizeof *oem);
 201         oem->type = htons(OFPET12_EXPERIMENTER);
 202         oem->code = htons(triplet->type);
 203         ofpbuf_put(buf, &vendor, sizeof vendor);
 204     }
 205
 206     ofpbuf_put(buf, data, data_len);
 207     ofpmsg_update_length(buf);
 208
 209     return buf;
 210 }
 211
 212 /* Creates and returns an OpenFlow message of type OFPT_ERROR that conveys the
 213  * given 'error'.
 214  *
 215  * 'oh->version' determines the OpenFlow version of the error reply.
 216  * 'oh->xid' determines the xid of the error reply.
 217  * The error reply will contain an initial subsequence of 'oh', up to
 218  * 'oh->length' or 64 bytes, whichever is shorter.
 219  *
 220  * This function isn't appropriate for encoding OFPET_HELLO_FAILED error
 221  * messages.  Use ofperr_encode_hello() instead. */
 222 struct ofpbuf *
 223 ofperr_encode_reply(enum ofperr error, const struct ofp_header *oh)
 224 {
 225     uint16_t len = ntohs(oh->length);
 226
 227     return ofperr_encode_msg__(error, oh->version, oh->xid, oh, MIN(len, 64));
 228 }
 229
 230 /* Creates and returns an OpenFlow message of type OFPT_ERROR that conveys the
 231  * given 'error', in the error domain 'domain'.  The error message will include
 232  * the additional null-terminated text string 's'.
 233  *
 234  * If 'version' is an unknown version then OFP10_VERSION is used.
 235  * OFPET_HELLO_FAILED error messages are supposed to be backward-compatible,
 236  * so in theory this should work. */
 237 struct ofpbuf *
 238 ofperr_encode_hello(enum ofperr error, enum ofp_version ofp_version,
 239                     const char *s)
 240 {
 241     return ofperr_encode_msg__(error, ofp_version, htonl(0), s, strlen(s));
 242 }
 243
 244 int
 245 ofperr_get_vendor(enum ofperr error, enum ofp_version version)
 246 {
 247     const struct ofperr_domain *domain = ofperr_domain_from_version(version);
 248     return domain ? ofperr_get_triplet__(error, domain)->vendor : -1;
 249 }
 250
 251 /* Returns the value that would go into an OFPT_ERROR message's 'type' for
 252  * encoding 'error' in 'domain'.  Returns -1 if 'error' is not encodable in
 253  * 'version' or 'version' is unknown.
 254  *
 255  * 'error' must be a valid OFPERR_* code, as checked by ofperr_is_valid(). */
 256 int
 257 ofperr_get_type(enum ofperr error, enum ofp_version version)
 258 {
 259     const struct ofperr_domain *domain = ofperr_domain_from_version(version);
 260     return domain ? ofperr_get_triplet__(error, domain)->type : -1;
 261 }
 262
 263 /* Returns the value that would go into an OFPT_ERROR message's 'code' for
 264  * encoding 'error' in 'domain'.  Returns -1 if 'error' is not encodable in
 265  * 'version', 'version' is unknown or if 'error' represents a category
 266  * rather than a specific error.
 267  *
 268  *
 269  * 'error' must be a valid OFPERR_* code, as checked by ofperr_is_valid(). */
 270 int
 271 ofperr_get_code(enum ofperr error, enum ofp_version version)
 272 {
 273     const struct ofperr_domain *domain = ofperr_domain_from_version(version);
 274     return domain ? ofperr_get_triplet__(error, domain)->code : -1;
 275 }
 276
 277 /* Tries to decode 'oh', which should be an OpenFlow OFPT_ERROR message.
 278  * Returns an OFPERR_* constant on success, 0 on failure.
 279  *
 280  * If 'payload' is nonnull, on success '*payload' is initialized with a copy of
 281  * the error's payload (copying is required because the payload is not properly
 282  * aligned).  The caller must free the payload (with ofpbuf_uninit()) when it
 283  * is no longer needed.  On failure, '*payload' is cleared. */
 284 enum ofperr
 285 ofperr_decode_msg(const struct ofp_header *oh, struct ofpbuf *payload)
 286 {
 287     const struct ofp_error_msg *oem;
 288     enum ofpraw raw;
 289     uint16_t type, code;
 290     uint32_t vendor;
 291
 292     if (payload) {
 293         memset(payload, 0, sizeof *payload);
 294     }
 295
 296     /* Pull off the error message. */
 297     struct ofpbuf b = ofpbuf_const_initializer(oh, ntohs(oh->length));
 298     enum ofperr error = ofpraw_pull(&raw, &b);
 299     if (error) {
 300         return 0;
 301     }
 302     oem = ofpbuf_pull(&b, sizeof *oem);
 303
 304     /* Get the error type and code. */
 305     vendor = 0;
 306     type = ntohs(oem->type);
 307     code = ntohs(oem->code);
 308     if (type == NXET_VENDOR && code == NXVC_VENDOR_ERROR) {
 309         const struct nx_vendor_error *nve = ofpbuf_try_pull(&b, sizeof *nve);
 310         if (!nve) {
 311             return 0;
 312         }
 313
 314         vendor = ntohl(nve->vendor);
 315         type = ntohs(nve->type);
 316         code = ntohs(nve->code);
 317     } else if (type == OFPET12_EXPERIMENTER) {
 318         const ovs_be32 *vendorp = ofpbuf_try_pull(&b, sizeof *vendorp);
 319         if (!vendorp) {
 320             return 0;
 321         }
 322
 323         vendor = ntohl(*vendorp);
 324         type = code;
 325         code = 0;
 326     }
 327
 328     /* Translate the error type and code into an ofperr. */
 329     error = ofperr_decode(oh->version, vendor, type, code);
 330     if (error && payload) {
 331         ofpbuf_init(payload, b.size);
 332         ofpbuf_push(payload, b.data, b.size);
 333     }
 334     return error;
 335 }
 336
 337 /* If 'error' is a valid OFPERR_* value, returns its name
 338  * (e.g. "OFPBRC_BAD_TYPE" for OFPBRC_BAD_TYPE).  Otherwise, assumes that
 339  * 'error' is a positive errno value and returns what ovs_strerror() produces
 340  * for 'error'.  */
 341 const char *
 342 ofperr_to_string(enum ofperr error)
 343 {
 344     return (ofperr_is_valid(error)
 345             ? ofperr_get_name(error)
 346             : ovs_strerror(error));
 347 }