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 nexthop information. */
  88         struct {
  89                 int family;
  90                 union g_addr address;
  91                 mpls_label_t label;
  92         } nexthop;
  93
  94         /* (LAN-)Adjacency-SID Sub-TLV. */
  95         union {
  96                 struct isis_adj_sid *adj_sid;
  97                 struct isis_lan_adj_sid *ladj_sid;
  98         } u;
  99
 100         /* Back pointer to IS-IS adjacency. */
 101         struct isis_adjacency *adj;
 102 };
 103
 104 /* Segment Routing Prefix-SID type. */
 105 enum sr_prefix_type {
 106         ISIS_SR_PREFIX_LOCAL = 0,
 107         ISIS_SR_PREFIX_REMOTE,
 108 };
 109
 110 /* Segment Routing Nexthop Information. */
 111 struct sr_nexthop_info {
 112         mpls_label_t label;
 113         time_t uptime;
 114 };
 115
 116 /* State of Object (SR-Node and SR-Prefix) stored in SRDB */
 117 enum srdb_state {
 118         SRDB_STATE_VALIDATED = 0,
 119         SRDB_STATE_NEW,
 120         SRDB_STATE_MODIFIED,
 121         SRDB_STATE_UNCHANGED
 122 };
 123
 124 /* Segment Routing Prefix-SID. */
 125 struct sr_prefix {
 126         /* SRDB RB-tree entries. */
 127         struct srdb_node_prefix_item node_entry;
 128         struct srdb_area_prefix_item area_entry;
 129
 130         /* IP prefix. */
 131         struct prefix prefix;
 132
 133         /* SID value, algorithm and flags subTLVs. */
 134         struct isis_prefix_sid sid;
 135
 136         /* Input label value. */
 137         mpls_label_t input_label;
 138
 139         /* Prefix-SID type. */
 140         enum sr_prefix_type type;
 141         union {
 142                 struct {
 143                         /* Information about this local Prefix-SID. */
 144                         struct sr_nexthop_info info;
 145                 } local;
 146                 struct {
 147                         /* Route associated to this remote Prefix-SID. */
 148                         struct isis_route_info *rinfo;
 149                 } remote;
 150         } u;
 151
 152         /* Backpointer to Segment Routing node. */
 153         struct sr_node *srn;
 154
 155         /* SR-Prefix State used while the LSPDB is being parsed. */
 156         enum srdb_state state;
 157 };
 158
 159 /* Segment Routing node. */
 160 struct sr_node {
 161         /* SRDB RB-tree entry. */
 162         struct srdb_node_item entry;
 163
 164         /* IS-IS level: ISIS_LEVEL1 or ISIS_LEVEL2. */
 165         int level;
 166
 167         /* IS-IS node identifier. */
 168         uint8_t sysid[ISIS_SYS_ID_LEN];
 169
 170         /* Segment Routing node capabilities (SRGB, SR Algorithms) subTLVs. */
 171         struct isis_router_cap cap;
 172
 173         /* List of Prefix-SIDs advertised by this node. */
 174         struct srdb_node_prefix_head prefix_sids;
 175
 176         /* Backpointer to IS-IS area. */
 177         struct isis_area *area;
 178
 179         /* SR-Node State used while the LSPDB is being parsed. */
 180         enum srdb_state state;
 181 };
 182
 183 /* SID type. NOTE: these values must be in sync with the YANG module. */
 184 enum sr_sid_value_type {
 185         SR_SID_VALUE_TYPE_INDEX = 0,
 186         SR_SID_VALUE_TYPE_ABSOLUTE = 1,
 187 };
 188
 189 #define IS_SID_VALUE(flag) CHECK_FLAG(flag, ISIS_PREFIX_SID_VALUE)
 190
 191 /* Last Hop Behavior. NOTE: these values must be in sync with the YANG module */
 192 enum sr_last_hop_behavior {
 193         SR_LAST_HOP_BEHAVIOR_EXP_NULL = 0,
 194         SR_LAST_HOP_BEHAVIOR_NO_PHP = 1,
 195         SR_LAST_HOP_BEHAVIOR_PHP = 2,
 196 };
 197
 198 /* Segment Routing Prefix-SID configuration. */
 199 struct sr_prefix_cfg {
 200         /* SRDB RB-tree entry. */
 201         struct srdb_prefix_cfg_item entry;
 202
 203         /* IP prefix. */
 204         struct prefix prefix;
 205
 206         /* SID value. */
 207         uint32_t sid;
 208
 209         /* SID value type. */
 210         enum sr_sid_value_type sid_type;
 211
 212         /* SID last hop behavior. */
 213         enum sr_last_hop_behavior last_hop_behavior;
 214
 215         /* Does this Prefix-SID refer to a loopback address (Node-SID)? */
 216         bool node_sid;
 217
 218         /* Backpointer to IS-IS area. */
 219         struct isis_area *area;
 220 };
 221
 222 /* Per-area IS-IS Segment Routing Data Base (SRDB). */
 223 struct isis_sr_db {
 224         /* Global Operational status of Segment Routing. */
 225         bool enabled;
 226
 227         /* Thread timer to start Label Manager */
 228         struct thread *t_start_lm;
 229
 230         /* List of local Adjacency-SIDs. */
 231         struct list *adj_sids;
 232
 233         /* Segment Routing Node information per IS-IS level. */
 234         struct srdb_node_head sr_nodes[ISIS_LEVELS];
 235
 236         /* Segment Routing Prefix-SIDs per IS-IS level. */
 237         struct srdb_area_prefix_head prefix_sids[ISIS_LEVELS];
 238
 239         /* Management of SRLB & SRGB allocation */
 240         struct sr_local_block srlb;
 241         bool srgb_active;
 242
 243         /* Area Segment Routing configuration. */
 244         struct {
 245                 /* Administrative status of Segment Routing. */
 246                 bool enabled;
 247
 248                 /* Segment Routing Global Block lower & upper bound. */
 249                 uint32_t srgb_lower_bound;
 250                 uint32_t srgb_upper_bound;
 251
 252                 /* Segment Routing Local Block lower & upper bound. */
 253                 uint32_t srlb_lower_bound;
 254                 uint32_t srlb_upper_bound;
 255
 256                 /* Maximum SID Depth supported by the node. */
 257                 uint8_t msd;
 258
 259                 /* Prefix-SID mappings. */
 260                 struct srdb_prefix_cfg_head prefix_sids;
 261         } config;
 262 };
 263
 264 /* Prototypes. */
 265 extern int isis_sr_cfg_srgb_update(struct isis_area *area, uint32_t lower_bound,
 266                                    uint32_t upper_bound);
 267 extern int isis_sr_cfg_srlb_update(struct isis_area *area, uint32_t lower_bound,
 268                                    uint32_t upper_bound);
 269 extern struct sr_prefix_cfg *
 270 isis_sr_cfg_prefix_add(struct isis_area *area, const struct prefix *prefix);
 271 extern void isis_sr_cfg_prefix_del(struct sr_prefix_cfg *pcfg);
 272 extern struct sr_prefix_cfg *
 273 isis_sr_cfg_prefix_find(struct isis_area *area, union prefixconstptr prefix);
 274 extern void isis_sr_prefix_cfg2subtlv(const struct sr_prefix_cfg *pcfg,
 275                                       bool external,
 276                                       struct isis_prefix_sid *psid);
 277 extern void isis_sr_nexthop_update(struct sr_nexthop_info *srnh,
 278                                    mpls_label_t label);
 279 extern void isis_sr_nexthop_reset(struct sr_nexthop_info *srnh);
 280 extern void isis_area_verify_sr(struct isis_area *area);
 281 extern int isis_sr_start(struct isis_area *area);
 282 extern void isis_sr_stop(struct isis_area *area);
 283 extern void isis_sr_area_init(struct isis_area *area);
 284 extern void isis_sr_area_term(struct isis_area *area);
 285 extern void isis_sr_init(void);
 286 extern void isis_sr_term(void);
 287
 288 #endif /* _FRR_ISIS_SR_H */