isisd/isis_sr.h

   1 /*
   2  * This is an implementation of Segment Routing for IS-IS as per RFC 8667
   3  *
   4  * Copyright (C) 2019 Orange http://www.orange.com
   5  *
   6  * Author: Olivier Dugeon <olivier.dugeon@orange.com>
   7  * Contributor: Renato Westphal <renato@opensourcerouting.org> for NetDEF
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the Free
  11  * Software Foundation; either version 2 of the License, or (at your option)
  12  * any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful, but WITHOUT
  15  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  17  * more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; see the file COPYING; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #ifndef _FRR_ISIS_SR_H
  25 #define _FRR_ISIS_SR_H
  26
  27 #include "lib/linklist.h"
  28 #include "lib/mpls.h"
  29 #include "lib/nexthop.h"
  30 #include "lib/typesafe.h"
  31
  32 #include "isisd/isis_tlvs.h"
  33
  34 /*
  35  * Segment Routing information is transported through the following Sub-TLVs:
  36  *
  37  * Sub-TLV Name                         Value   TLVs
  38  * ---------------------------------------------------------------------
  39  * SID Label                             1
  40  *
  41  * Prefix Segment Identifier             3      135, 235, 236 and 237
  42  *
  43  * Adjacency Segment Identifier         31      22, 23, 141, 222 and 223
  44  * LAN Adjacency Segment Identifier     32      22, 23, 141, 222 and 223
  45  *
  46  * Segment Routing Capability            2      242
  47  * Segment Routing Algorithm            19      242
  48  * Node Maximum Stack Depth (MSD)       23      242
  49  *
  50  * Sub-TLV definitions, serialization and de-serialization are defined
  51  * in isis_tlvs.[c,h].
  52  */
  53
  54 #define SRGB_LOWER_BOUND               16000
  55 #define SRGB_UPPER_BOUND               23999
  56 #define SRLB_LOWER_BOUND               15000
  57 #define SRLB_UPPER_BOUND               15999
  58
  59 /* Segment Routing Data Base (SRDB) RB-Tree structure */
  60 PREDECL_RBTREE_UNIQ(srdb_node)
  61 PREDECL_RBTREE_UNIQ(srdb_node_prefix)
  62 PREDECL_RBTREE_UNIQ(srdb_area_prefix)
  63 PREDECL_RBTREE_UNIQ(srdb_prefix_cfg)
  64
  65 /* Segment Routing Local Block allocation */
  66 struct sr_local_block {
  67         bool active;
  68         uint32_t start;
  69         uint32_t end;
  70         uint32_t current;
  71         uint32_t max_block;
  72         uint64_t *used_mark;
  73 };
  74 #define SRLB_BLOCK_SIZE 64
  75
  76 /* Segment Routing Adjacency-SID type. */
  77 enum sr_adj_type {
  78         ISIS_SR_ADJ_NORMAL = 0,
  79         ISIS_SR_LAN_BACKUP,
  80 };
  81
  82 /* Segment Routing Adjacency. */
  83 struct sr_adjacency {
  84         /* Adjacency type. */
  85         enum sr_adj_type type;
  86
  87         /* Adjacency-SID input label. */
  88         mpls_label_t input_label;
  89
  90         /* Adjacency-SID nexthop information. */
  91         struct {
  92                 int family;
  93                 union g_addr address;
  94         } nexthop;
  95
  96         /* Adjacency-SID TI-LFA backup nexthops. */
  97         struct list *backup_nexthops;
  98
  99         /* (LAN-)Adjacency-SID Sub-TLV. */
 100         union {
 101                 struct isis_adj_sid *adj_sid;
 102                 struct isis_lan_adj_sid *ladj_sid;
 103         } u;
 104
 105         /* Back pointer to IS-IS adjacency. */
 106         struct isis_adjacency *adj;
 107 };
 108
 109 /* Segment Routing Prefix-SID type. */
 110 enum sr_prefix_type {
 111         ISIS_SR_PREFIX_LOCAL = 0,
 112         ISIS_SR_PREFIX_REMOTE,
 113 };
 114
 115 /* Segment Routing Nexthop Information. */
 116 struct sr_nexthop_info {
 117         mpls_label_t label;
 118         time_t uptime;
 119 };
 120
 121 /* State of Object (SR-Node and SR-Prefix) stored in SRDB */
 122 enum srdb_state {
 123         SRDB_STATE_VALIDATED = 0,
 124         SRDB_STATE_NEW,
 125         SRDB_STATE_MODIFIED,
 126         SRDB_STATE_UNCHANGED
 127 };
 128
 129 /* Segment Routing Prefix-SID. */
 130 struct sr_prefix {
 131         /* SRDB RB-tree entries. */
 132         struct srdb_node_prefix_item node_entry;
 133         struct srdb_area_prefix_item area_entry;
 134
 135         /* IP prefix. */
 136         struct prefix prefix;
 137
 138         /* SID value, algorithm and flags subTLVs. */
 139         struct isis_prefix_sid sid;
 140
 141         /* Input label value. */
 142         mpls_label_t input_label;
 143
 144         /* Prefix-SID type. */
 145         enum sr_prefix_type type;
 146         union {
 147                 struct {
 148                         /* Information about this local Prefix-SID. */
 149                         struct sr_nexthop_info info;
 150                 } local;
 151                 struct {
 152                         /* Route associated to this remote Prefix-SID. */
 153                         struct isis_route_info *rinfo;
 154                 } remote;
 155         } u;
 156
 157         /* Backpointer to Segment Routing node. */
 158         struct sr_node *srn;
 159
 160         /* SR-Prefix State used while the LSPDB is being parsed. */
 161         enum srdb_state state;
 162 };
 163
 164 /* Segment Routing node. */
 165 struct sr_node {
 166         /* SRDB RB-tree entry. */
 167         struct srdb_node_item entry;
 168
 169         /* IS-IS level: ISIS_LEVEL1 or ISIS_LEVEL2. */
 170         int level;
 171
 172         /* IS-IS node identifier. */
 173         uint8_t sysid[ISIS_SYS_ID_LEN];
 174
 175         /* Segment Routing node capabilities (SRGB, SR Algorithms) subTLVs. */
 176         struct isis_router_cap cap;
 177
 178         /* List of Prefix-SIDs advertised by this node. */
 179         struct srdb_node_prefix_head prefix_sids;
 180
 181         /* Backpointer to IS-IS area. */
 182         struct isis_area *area;
 183
 184         /* SR-Node State used while the LSPDB is being parsed. */
 185         enum srdb_state state;
 186 };
 187
 188 /* SID type. NOTE: these values must be in sync with the YANG module. */
 189 enum sr_sid_value_type {
 190         SR_SID_VALUE_TYPE_INDEX = 0,
 191         SR_SID_VALUE_TYPE_ABSOLUTE = 1,
 192 };
 193
 194 #define IS_SID_VALUE(flag) CHECK_FLAG(flag, ISIS_PREFIX_SID_VALUE)
 195
 196 /* Last Hop Behavior. NOTE: these values must be in sync with the YANG module */
 197 enum sr_last_hop_behavior {
 198         SR_LAST_HOP_BEHAVIOR_EXP_NULL = 0,
 199         SR_LAST_HOP_BEHAVIOR_NO_PHP = 1,
 200         SR_LAST_HOP_BEHAVIOR_PHP = 2,
 201 };
 202
 203 /* Segment Routing Prefix-SID configuration. */
 204 struct sr_prefix_cfg {
 205         /* SRDB RB-tree entry. */
 206         struct srdb_prefix_cfg_item entry;
 207
 208         /* IP prefix. */
 209         struct prefix prefix;
 210
 211         /* SID value. */
 212         uint32_t sid;
 213
 214         /* SID value type. */
 215         enum sr_sid_value_type sid_type;
 216
 217         /* SID last hop behavior. */
 218         enum sr_last_hop_behavior last_hop_behavior;
 219
 220         /* Does this Prefix-SID refer to a loopback address (Node-SID)? */
 221         bool node_sid;
 222
 223         /* Backpointer to IS-IS area. */
 224         struct isis_area *area;
 225 };
 226
 227 /* Per-area IS-IS Segment Routing Data Base (SRDB). */
 228 struct isis_sr_db {
 229         /* Global Operational status of Segment Routing. */
 230         bool enabled;
 231
 232         /* Thread timer to start Label Manager */
 233         struct thread *t_start_lm;
 234
 235         /* List of local Adjacency-SIDs. */
 236         struct list *adj_sids;
 237
 238         /* Segment Routing Node information per IS-IS level. */
 239         struct srdb_node_head sr_nodes[ISIS_LEVELS];
 240
 241         /* Segment Routing Prefix-SIDs per IS-IS level. */
 242         struct srdb_area_prefix_head prefix_sids[ISIS_LEVELS];
 243
 244         /* Management of SRLB & SRGB allocation */
 245         struct sr_local_block srlb;
 246         bool srgb_active;
 247
 248         /* Area Segment Routing configuration. */
 249         struct {
 250                 /* Administrative status of Segment Routing. */
 251                 bool enabled;
 252
 253                 /* Segment Routing Global Block lower & upper bound. */
 254                 uint32_t srgb_lower_bound;
 255                 uint32_t srgb_upper_bound;
 256
 257                 /* Segment Routing Local Block lower & upper bound. */
 258                 uint32_t srlb_lower_bound;
 259                 uint32_t srlb_upper_bound;
 260
 261                 /* Maximum SID Depth supported by the node. */
 262                 uint8_t msd;
 263
 264                 /* Prefix-SID mappings. */
 265                 struct srdb_prefix_cfg_head prefix_sids;
 266         } config;
 267 };
 268
 269 /* Prototypes. */
 270 extern int isis_sr_cfg_srgb_update(struct isis_area *area, uint32_t lower_bound,
 271                                    uint32_t upper_bound);
 272 extern int isis_sr_cfg_srlb_update(struct isis_area *area, uint32_t lower_bound,
 273                                    uint32_t upper_bound);
 274 extern struct sr_prefix_cfg *
 275 isis_sr_cfg_prefix_add(struct isis_area *area, const struct prefix *prefix);
 276 extern void isis_sr_cfg_prefix_del(struct sr_prefix_cfg *pcfg);
 277 extern struct sr_prefix_cfg *
 278 isis_sr_cfg_prefix_find(struct isis_area *area, union prefixconstptr prefix);
 279 extern void isis_sr_prefix_cfg2subtlv(const struct sr_prefix_cfg *pcfg,
 280                                       bool external,
 281                                       struct isis_prefix_sid *psid);
 282 extern void isis_sr_nexthop_update(struct sr_nexthop_info *srnh,
 283                                    mpls_label_t label);
 284 extern void isis_sr_nexthop_reset(struct sr_nexthop_info *srnh);
 285 extern void sr_adj_sid_add_single(struct isis_adjacency *adj, int family,
 286                                   bool backup, struct list *nexthops);
 287 extern struct sr_adjacency *isis_sr_adj_sid_find(struct isis_adjacency *adj,
 288                                                  int family,
 289                                                  enum sr_adj_type type);
 290 extern void isis_area_delete_backup_adj_sids(struct isis_area *area, int level);
 291 extern void isis_area_verify_sr(struct isis_area *area);
 292 extern int isis_sr_start(struct isis_area *area);
 293 extern void isis_sr_stop(struct isis_area *area);
 294 extern void isis_sr_area_init(struct isis_area *area);
 295 extern void isis_sr_area_term(struct isis_area *area);
 296 extern void isis_sr_init(void);
 297 extern void isis_sr_term(void);
 298
 299 #endif /* _FRR_ISIS_SR_H */