src/vnet/adj/rewrite.h

   1 /*
   2  * Copyright (c) 2015 Cisco and/or its affiliates.
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15 /*
  16  * rewrite.h: packet rewrite
  17  *
  18  * Copyright (c) 2008 Eliot Dresselhaus
  19  *
  20  * Permission is hereby granted, free of charge, to any person obtaining
  21  * a copy of this software and associated documentation files (the
  22  * "Software"), to deal in the Software without restriction, including
  23  * without limitation the rights to use, copy, modify, merge, publish,
  24  * distribute, sublicense, and/or sell copies of the Software, and to
  25  * permit persons to whom the Software is furnished to do so, subject to
  26  * the following conditions:
  27  *
  28  * The above copyright notice and this permission notice shall be
  29  * included in all copies or substantial portions of the Software.
  30  *
  31  *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  32  *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  33  *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  34  *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  35  *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  36  *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  37  *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  38  */
  39
  40 #ifndef included_vnet_rewrite_h
  41 #define included_vnet_rewrite_h
  42
  43 #include <vlib/vlib.h>
  44 #include <vnet/l3_types.h>
  45
  46 /* Consider using vector types for speed? */
  47 typedef uword vnet_rewrite_data_t;
  48
  49 /**
  50  * Flags associated with the rewrite/adjacency
  51  */
  52 typedef enum vnet_rewrite_flags_t_
  53 {
  54   /**
  55    * This adjacency/interface has output features configured
  56    */
  57   VNET_REWRITE_HAS_FEATURES = (1 << 0),
  58 } __attribute__ ((packed)) vnet_rewrite_flags_t;
  59
  60 /* *INDENT-OFF* */
  61 typedef CLIB_PACKED (struct {
  62   /* Interface to mark re-written packets with. */
  63   u32 sw_if_index;
  64
  65   /* Next node to feed after packet rewrite is done. */
  66   u16 next_index;
  67
  68   /* Number of bytes in rewrite data. */
  69   u16 data_bytes;
  70
  71   /* Max packet size layer 3 (MTU) for output interface.
  72      Used for MTU check after packet rewrite. */
  73   u16 max_l3_packet_bytes;
  74
  75   /* Data-plane flags on the adjacency/rewrite */
  76   vnet_rewrite_flags_t flags;
  77
  78   /* When dynamically writing a multicast destination L2 addresss
  79    * this is the offset from the IP address at which to write in the
  80    * IP->MAC address translation.
  81    */
  82   u8 dst_mcast_offset;
  83
  84   /* Rewrite string starting at end and going backwards. */
  85   u8 data[0];
  86 }) vnet_rewrite_header_t;
  87 /* *INDENT-ON* */
  88
  89 /**
  90  * At 16 bytes of rewrite herader we have enought space left for a IPv6
  91  * (40 bytes) + LISP-GPE (8 bytes) in the cache line
  92  */
  93 STATIC_ASSERT (sizeof (vnet_rewrite_header_t) <= 16,
  94                "Rewrite header too big");
  95
  96 /*
  97   Helper macro for declaring rewrite string w/ given max-size.
  98
  99   Typical usage:
 100     typedef struct {
 101       //
 102       int a, b;
 103
 104       // Total adjacency is 64 bytes.
 105       vnet_rewrite_declare(64 - 2*sizeof(int)) rw;
 106     } my_adjacency_t;
 107 */
 108 #define VNET_DECLARE_REWRITE                         \
 109   struct                                             \
 110   {                                                  \
 111     vnet_rewrite_header_t rewrite_header;            \
 112                                                      \
 113     u8 rewrite_data[(VNET_REWRITE_TOTAL_BYTES) -     \
 114                     sizeof (vnet_rewrite_header_t)]; \
 115   }
 116
 117 always_inline void
 118 vnet_rewrite_clear_data_internal (vnet_rewrite_header_t * rw, int max_size)
 119 {
 120   /* Sanity check values carefully for this clib_memset operation */
 121   ASSERT ((max_size > 0) && (max_size < VLIB_BUFFER_PRE_DATA_SIZE));
 122
 123   rw->data_bytes = 0;
 124   clib_memset (rw->data, 0xfe, max_size);
 125 }
 126
 127 always_inline void
 128 vnet_rewrite_set_data_internal (vnet_rewrite_header_t * rw,
 129                                 int max_size, void *data, int data_bytes)
 130 {
 131   /* Sanity check values carefully for this clib_memset operation */
 132   ASSERT ((max_size > 0) && (max_size < VLIB_BUFFER_PRE_DATA_SIZE));
 133   ASSERT ((data_bytes >= 0) && (data_bytes < max_size));
 134
 135   rw->data_bytes = data_bytes;
 136   clib_memcpy_fast (rw->data, data, data_bytes);
 137   clib_memset (rw->data + data_bytes, 0xfe, max_size - data_bytes);
 138 }
 139
 140 #define vnet_rewrite_set_data(rw,data,data_bytes)               \
 141   vnet_rewrite_set_data_internal (&((rw).rewrite_header),       \
 142                                   sizeof ((rw).rewrite_data),   \
 143                                   (data),                       \
 144                                   (data_bytes))
 145
 146 always_inline void *
 147 vnet_rewrite_get_data_internal (vnet_rewrite_header_t * rw, int max_size)
 148 {
 149   ASSERT (rw->data_bytes <= max_size);
 150   return rw->data;
 151 }
 152
 153 #define vnet_rewrite_get_data(rw) \
 154   vnet_rewrite_get_data_internal (&((rw).rewrite_header), sizeof ((rw).rewrite_data))
 155
 156 always_inline void
 157 _vnet_rewrite_one_header (vnet_rewrite_header_t * h0,
 158                           void *packet0, int most_likely_size)
 159 {
 160   /* 0xfefe => poisoned adjacency => crash */
 161   ASSERT (h0->data_bytes != 0xfefe);
 162   if (PREDICT_TRUE (most_likely_size == h0->data_bytes))
 163     {
 164       clib_memcpy_fast ((u8 *) packet0 - most_likely_size,
 165                         h0->data, most_likely_size);
 166     }
 167   else
 168     {
 169       clib_memcpy_fast ((u8 *) packet0 - h0->data_bytes,
 170                         h0->data, h0->data_bytes);
 171     }
 172 }
 173
 174 always_inline void
 175 _vnet_rewrite_two_headers (vnet_rewrite_header_t * h0,
 176                            vnet_rewrite_header_t * h1,
 177                            void *packet0, void *packet1, int most_likely_size)
 178 {
 179   /* 0xfefe => poisoned adjacency => crash */
 180   ASSERT (h0->data_bytes != 0xfefe);
 181   ASSERT (h1->data_bytes != 0xfefe);
 182   if (PREDICT_TRUE
 183       (most_likely_size == h0->data_bytes
 184        && most_likely_size == h1->data_bytes))
 185     {
 186       clib_memcpy_fast ((u8 *) packet0 - most_likely_size,
 187                         h0->data, most_likely_size);
 188       clib_memcpy_fast ((u8 *) packet1 - most_likely_size,
 189                         h1->data, most_likely_size);
 190     }
 191   else
 192     {
 193       clib_memcpy_fast ((u8 *) packet0 - h0->data_bytes,
 194                         h0->data, h0->data_bytes);
 195       clib_memcpy_fast ((u8 *) packet1 - h1->data_bytes,
 196                         h1->data, h1->data_bytes);
 197     }
 198 }
 199
 200 #define vnet_rewrite_one_header(rw0,p0,most_likely_size)        \
 201   _vnet_rewrite_one_header (&((rw0).rewrite_header), (p0),      \
 202                             (most_likely_size))
 203
 204 #define vnet_rewrite_two_headers(rw0,rw1,p0,p1,most_likely_size)        \
 205   _vnet_rewrite_two_headers (&((rw0).rewrite_header), &((rw1).rewrite_header), \
 206                              (p0), (p1),                                \
 207                              (most_likely_size))
 208
 209 always_inline void
 210 vnet_ip_mcast_fixup_header (u32 dst_mcast_mask,
 211                             u32 dst_mcast_offset, u32 * addr, u8 * packet0)
 212 {
 213   if (PREDICT_TRUE (0 != dst_mcast_offset))
 214     {
 215       /* location to write to in the packet */
 216       u8 *p0 = packet0 - dst_mcast_offset;
 217       u32 *p1 = (u32 *) p0;
 218
 219       *p1 |= (*addr & dst_mcast_mask);
 220     }
 221 }
 222
 223 #define VNET_REWRITE_FOR_SW_INTERFACE_ADDRESS_BROADCAST ((void *) 0)
 224 /** Deprecated */
 225 void vnet_rewrite_for_sw_interface (struct vnet_main_t *vnm,
 226                                     vnet_link_t packet_type,
 227                                     u32 sw_if_index,
 228                                     u32 node_index,
 229                                     void *dst_address,
 230                                     vnet_rewrite_header_t * rw,
 231                                     u32 max_rewrite_bytes);
 232
 233 u32 vnet_tx_node_index_for_sw_interface (struct vnet_main_t *vnm,
 234                                          u32 sw_if_index);
 235
 236 void vnet_rewrite_init (struct vnet_main_t *vnm,
 237                         u32 sw_if_index,
 238                         vnet_link_t linkt,
 239                         u32 this_node,
 240                         u32 next_node, vnet_rewrite_header_t * rw);
 241
 242 void vnet_rewrite_update_mtu (struct vnet_main_t *vnm,
 243                               vnet_link_t linkt, vnet_rewrite_header_t * rw);
 244
 245 u8 *vnet_build_rewrite_for_sw_interface (struct vnet_main_t *vnm,
 246                                          u32 sw_if_index,
 247                                          vnet_link_t packet_type,
 248                                          const void *dst_address);
 249 void vnet_update_adjacency_for_sw_interface (struct vnet_main_t *vnm,
 250                                              u32 sw_if_index, u32 ai);
 251
 252 format_function_t format_vnet_rewrite;
 253
 254 serialize_function_t serialize_vnet_rewrite, unserialize_vnet_rewrite;
 255
 256 #endif /* included_vnet_rewrite_h */
 257
 258 /*
 259  * fd.io coding-style-patch-verification: ON
 260  *
 261  * Local Variables:
 262  * eval: (c-set-style "gnu")
 263  * End:
 264  */