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_prefix_cfg)
  61
  62 /*
  63  * Segment Routing Prefix-SID information.
  64  *
  65  * This structure is intended to be embedded inside other structures that
  66  * might or might not contain Prefix-SID information.
  67  */
  68 struct isis_sr_psid_info {
  69         /* Prefix-SID Sub-TLV information. */
  70         struct isis_prefix_sid sid;
  71
  72         /* Resolved input/output label. */
  73         mpls_label_t label;
  74
  75         /* Indicates whether the Prefix-SID is present or not. */
  76         bool present;
  77 };
  78
  79 /* Segment Routing Local Block allocation */
  80 struct sr_local_block {
  81         bool active;
  82         uint32_t start;
  83         uint32_t end;
  84         uint32_t current;
  85         uint32_t max_block;
  86         uint64_t *used_mark;
  87 };
  88 #define SRLB_BLOCK_SIZE 64
  89
  90 /* Segment Routing Adjacency-SID type. */
  91 enum sr_adj_type {
  92         ISIS_SR_ADJ_NORMAL = 0,
  93         ISIS_SR_LAN_BACKUP,
  94 };
  95
  96 /* Segment Routing Adjacency. */
  97 struct sr_adjacency {
  98         /* Adjacency type. */
  99         enum sr_adj_type type;
 100
 101         /* Adjacency-SID input label. */
 102         mpls_label_t input_label;
 103
 104         /* Adjacency-SID nexthop information. */
 105         struct {
 106                 int family;
 107                 union g_addr address;
 108         } nexthop;
 109
 110         /* Adjacency-SID TI-LFA backup nexthops. */
 111         struct list *backup_nexthops;
 112
 113         /* (LAN-)Adjacency-SID Sub-TLV. */
 114         union {
 115                 struct isis_adj_sid *adj_sid;
 116                 struct isis_lan_adj_sid *ladj_sid;
 117         } u;
 118
 119         /* Back pointer to IS-IS adjacency. */
 120         struct isis_adjacency *adj;
 121 };
 122
 123 /* SID type. NOTE: these values must be in sync with the YANG module. */
 124 enum sr_sid_value_type {
 125         SR_SID_VALUE_TYPE_INDEX = 0,
 126         SR_SID_VALUE_TYPE_ABSOLUTE = 1,
 127 };
 128
 129 #define IS_SID_VALUE(flag) CHECK_FLAG(flag, ISIS_PREFIX_SID_VALUE)
 130
 131 /* Last Hop Behavior. NOTE: these values must be in sync with the YANG module */
 132 enum sr_last_hop_behavior {
 133         SR_LAST_HOP_BEHAVIOR_EXP_NULL = 0,
 134         SR_LAST_HOP_BEHAVIOR_NO_PHP = 1,
 135         SR_LAST_HOP_BEHAVIOR_PHP = 2,
 136 };
 137
 138 /* Segment Routing Prefix-SID configuration. */
 139 struct sr_prefix_cfg {
 140         /* SRDB RB-tree entry. */
 141         struct srdb_prefix_cfg_item entry;
 142
 143         /* IP prefix. */
 144         struct prefix prefix;
 145
 146         /* SID value. */
 147         uint32_t sid;
 148
 149         /* SID value type. */
 150         enum sr_sid_value_type sid_type;
 151
 152         /* SID last hop behavior. */
 153         enum sr_last_hop_behavior last_hop_behavior;
 154
 155         /* Indicates whether the node flag must be explicitly unset. */
 156         bool n_flag_clear;
 157
 158         /* Does this Prefix-SID refer to a loopback address (Node-SID)? */
 159         bool node_sid;
 160
 161         /* Backpointer to IS-IS area. */
 162         struct isis_area *area;
 163 };
 164
 165 /* Per-area IS-IS Segment Routing Data Base (SRDB). */
 166 struct isis_sr_db {
 167         /* Global Operational status of Segment Routing. */
 168         bool enabled;
 169
 170         /* Thread timer to start Label Manager */
 171         struct thread *t_start_lm;
 172
 173         /* List of local Adjacency-SIDs. */
 174         struct list *adj_sids;
 175
 176         /* Management of SRLB & SRGB allocation */
 177         struct sr_local_block srlb;
 178         bool srgb_active;
 179
 180         /* Area Segment Routing configuration. */
 181         struct {
 182                 /* Administrative status of Segment Routing. */
 183                 bool enabled;
 184
 185                 /* Segment Routing Global Block lower & upper bound. */
 186                 uint32_t srgb_lower_bound;
 187                 uint32_t srgb_upper_bound;
 188
 189                 /* Segment Routing Local Block lower & upper bound. */
 190                 uint32_t srlb_lower_bound;
 191                 uint32_t srlb_upper_bound;
 192
 193                 /* Maximum SID Depth supported by the node. */
 194                 uint8_t msd;
 195
 196                 /* Prefix-SID mappings. */
 197                 struct srdb_prefix_cfg_head prefix_sids;
 198         } config;
 199 };
 200
 201 /* Prototypes. */
 202 extern struct isis_sr_block *isis_sr_find_srgb(struct lspdb_head *lspdb,
 203                                                const uint8_t *sysid);
 204 extern mpls_label_t sr_prefix_in_label(struct isis_area *area,
 205                                        struct isis_prefix_sid *psid,
 206                                        bool local);
 207 extern mpls_label_t sr_prefix_out_label(struct lspdb_head *lspdb, int family,
 208                                         struct isis_prefix_sid *psid,
 209                                         const uint8_t *nh_sysid, bool last_hop);
 210 extern int isis_sr_cfg_srgb_update(struct isis_area *area, uint32_t lower_bound,
 211                                    uint32_t upper_bound);
 212 extern int isis_sr_cfg_srlb_update(struct isis_area *area, uint32_t lower_bound,
 213                                    uint32_t upper_bound);
 214 extern struct sr_prefix_cfg *
 215 isis_sr_cfg_prefix_add(struct isis_area *area, const struct prefix *prefix);
 216 extern void isis_sr_cfg_prefix_del(struct sr_prefix_cfg *pcfg);
 217 extern struct sr_prefix_cfg *
 218 isis_sr_cfg_prefix_find(struct isis_area *area, union prefixconstptr prefix);
 219 extern void isis_sr_prefix_cfg2subtlv(const struct sr_prefix_cfg *pcfg,
 220                                       bool external,
 221                                       struct isis_prefix_sid *psid);
 222 extern void sr_adj_sid_add_single(struct isis_adjacency *adj, int family,
 223                                   bool backup, struct list *nexthops);
 224 extern struct sr_adjacency *isis_sr_adj_sid_find(struct isis_adjacency *adj,
 225                                                  int family,
 226                                                  enum sr_adj_type type);
 227 extern void isis_area_delete_backup_adj_sids(struct isis_area *area, int level);
 228 extern char *sr_op2str(char *buf, size_t size, mpls_label_t label_in,
 229                        mpls_label_t label_out);
 230 extern int isis_sr_start(struct isis_area *area);
 231 extern void isis_sr_stop(struct isis_area *area);
 232 extern void isis_sr_area_init(struct isis_area *area);
 233 extern void isis_sr_area_term(struct isis_area *area);
 234 extern void isis_sr_init(void);
 235 extern void isis_sr_term(void);
 236
 237 #endif /* _FRR_ISIS_SR_H */