llc.h

Go to the documentation of this file.

/*
 * Copyright (c) 2015 Cisco and/or its affiliates.
 * 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.
 */
/*
 * llc.h: LLC definitions
 *
 * Copyright (c) 2008 Eliot Dresselhaus
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef included_llc_h
#define included_llc_h

#include <vnet/vnet.h>
#include <vnet/pg/pg.h>

/* Protocol (SSAP/DSAP) types. */
#define foreach_llc_protocol                    \
  _ (null, 0x0)                                 \
  _ (sublayer, 0x2)                             \
  _ (sna_path_control, 0x4)                     \
  _ (ip4, 0x6)                                  \
  _ (sna1, 0x8)                                 \
  _ (sna2, 0xc)                                 \
  _ (sna3, 0x40)                                \
  _ (proway_lan, 0x0e)                          \
  _ (netware1, 0x10)                            \
  _ (netware2, 0xe0)                            \
  _ (osi_layer1, 0x14)                          \
  _ (osi_layer2, 0x20)                          \
  _ (osi_layer3, 0x34)                          \
  _ (osi_layer4, 0x54)                          \
  _ (osi_layer5, 0xfe)                          \
  _ (bpdu, 0x42)                                \
  _ (arp, 0x98)                                 \
  _ (snap, 0xaa)                                \
  _ (vines1, 0xba)                              \
  _ (vines2, 0xbc)                              \
  _ (netbios, 0xf0)                             \
  _ (global_dsap, 0xff)

typedef enum {
#define _(f,n) LLC_PROTOCOL_##f = n,
  foreach_llc_protocol
#undef _
} llc_protocol_t;

typedef struct {
#define LLC_DST_SAP_IS_GROUP (1 << 0)
#define LLC_SRC_SAP_IS_RESPONSE (1 << 0)
  u8 dst_sap, src_sap;

  /* Control byte.
     [0] 1 => supervisory 0 => information
     [1] unnumbered frame. */
  u8 control;

  /* Only present if (control & 3) != 3. */
  u8 extended_control[0];
} llc_header_t;

always_inline u16
llc_header_get_control (llc_header_t * h)
{
  u16 r = h->control;
  return r | ((((r & 3) != 3) ? h->extended_control[0] : 0) << 8);
}

always_inline u8
llc_header_length (llc_header_t * h)
{
  return ((h->control & 3) != 3 ? 4 : 3);
}

typedef struct {
  /* Name (a c string). */
  char * name;

  /* LLC protocol (SAP type). */
  llc_protocol_t protocol;

  /* Node which handles this type. */
  u32 node_index;

  /* Next index for this type. */
  u32 next_index;
} llc_protocol_info_t;

#define foreach_llc_error                       \
  _ (NONE, "no error")                          \
  _ (UNKNOWN_PROTOCOL, "unknown llc ssap/dsap") \
  _ (UNKNOWN_CONTROL, "control != 0x3")

typedef enum {
#define _(f,s) LLC_ERROR_##f,
  foreach_llc_error
#undef _
  LLC_N_ERROR,
} llc_error_t;

typedef struct {
  vlib_main_t * vlib_main;

  llc_protocol_info_t * protocol_infos;

  /* Hash tables mapping name/protocol to protocol info index. */
  uword * protocol_info_by_name, * protocol_info_by_protocol;

  /* llc-input next index indexed by protocol. */
  u8 input_next_by_protocol[256];
} llc_main_t;

always_inline llc_protocol_info_t *
llc_get_protocol_info (llc_main_t * m, llc_protocol_t protocol)
{
  uword * p = hash_get (m->protocol_info_by_protocol, protocol);
  return p ? vec_elt_at_index (m->protocol_infos, p[0]) : 0;
}

extern llc_main_t llc_main;

/* Register given node index to take input for given llc type. */
void
llc_register_input_protocol (vlib_main_t * vm,
                             llc_protocol_t protocol,
                             u32 node_index);

void llc_set_adjacency (vnet_rewrite_header_t * rw,
                        uword max_data_bytes,
                        llc_protocol_t protocol);

format_function_t format_llc_protocol;
format_function_t format_llc_header;
format_function_t format_llc_header_with_length;

/* Parse llc protocol as 0xXXXX or protocol name. */
unformat_function_t unformat_llc_protocol;

/* Parse llc header. */
unformat_function_t unformat_llc_header;
unformat_function_t unformat_pg_llc_header;

always_inline void
llc_setup_node (vlib_main_t * vm, u32 node_index)
{
  vlib_node_t * n = vlib_get_node (vm, node_index);
  pg_node_t * pn = pg_get_node (node_index);

  n->format_buffer = format_llc_header_with_length;
  n->unformat_buffer = unformat_llc_header;
  pn->unformat_edit = unformat_pg_llc_header;
}

#endif /* included_llc_h */