isisd/isis_sr.h

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * This is an implementation of Segment Routing for IS-IS as per RFC 8667
   4  *
   5  * Copyright (C) 2019 Orange http://www.orange.com
   6  *
   7  * Author: Olivier Dugeon <olivier.dugeon@orange.com>
   8  * Contributor: Renato Westphal <renato@opensourcerouting.org> for NetDEF
   9  */
  10
  11 #ifndef _FRR_ISIS_SR_H
  12 #define _FRR_ISIS_SR_H
  13
  14 #include "lib/linklist.h"
  15 #include "lib/mpls.h"
  16 #include "lib/nexthop.h"
  17 #include "lib/typesafe.h"
  18
  19 #include "isisd/isis_tlvs.h"
  20
  21 /*
  22  * Segment Routing information is transported through the following Sub-TLVs:
  23  *
  24  * Sub-TLV Name                         Value   TLVs
  25  * ---------------------------------------------------------------------
  26  * SID Label                             1
  27  *
  28  * Prefix Segment Identifier             3      135, 235, 236 and 237
  29  *
  30  * Adjacency Segment Identifier         31      22, 23, 141, 222 and 223
  31  * LAN Adjacency Segment Identifier     32      22, 23, 141, 222 and 223
  32  *
  33  * Segment Routing Capability            2      242
  34  * Segment Routing Algorithm            19      242
  35  * Node Maximum Stack Depth (MSD)       23      242
  36  *
  37  * Sub-TLV definitions, serialization and de-serialization are defined
  38  * in isis_tlvs.[c,h].
  39  */
  40
  41 #define SRGB_LOWER_BOUND               16000
  42 #define SRGB_UPPER_BOUND               23999
  43 #define SRLB_LOWER_BOUND               15000
  44 #define SRLB_UPPER_BOUND               15999
  45
  46 /* Segment Routing Data Base (SRDB) RB-Tree structure */
  47 PREDECL_RBTREE_UNIQ(srdb_prefix_cfg);
  48
  49 /*
  50  * Segment Routing Prefix-SID information.
  51  *
  52  * This structure is intended to be embedded inside other structures that
  53  * might or might not contain Prefix-SID information.
  54  */
  55 struct isis_sr_psid_info {
  56         /* Prefix-SID Sub-TLV information. */
  57         struct isis_prefix_sid sid;
  58
  59         /* Resolved input/output label. */
  60         mpls_label_t label;
  61
  62         /* Indicates whether the Prefix-SID is present or not. */
  63         bool present;
  64 };
  65
  66 /* Segment Routing Local Block allocation */
  67 struct sr_local_block {
  68         bool active;
  69         uint32_t start;
  70         uint32_t end;
  71         uint32_t current;
  72         uint32_t max_block;
  73         uint64_t *used_mark;
  74 };
  75 #define SRLB_BLOCK_SIZE 64
  76
  77 /* Segment Routing Adjacency-SID type. */
  78 enum sr_adj_type {
  79         ISIS_SR_ADJ_NORMAL = 0,
  80         ISIS_SR_LAN_BACKUP,
  81 };
  82
  83 /* Segment Routing Adjacency. */
  84 struct sr_adjacency {
  85         /* Adjacency type. */
  86         enum sr_adj_type type;
  87
  88         /* Adjacency-SID input label. */
  89         mpls_label_t input_label;
  90
  91         /* Adjacency-SID nexthop information. */
  92         struct {
  93                 int family;
  94                 union g_addr address;
  95         } nexthop;
  96
  97         /* Adjacency-SID TI-LFA backup nexthops. */
  98         struct list *backup_nexthops;
  99
 100         /* (LAN-)Adjacency-SID Sub-TLV. */
 101         union {
 102                 struct isis_adj_sid *adj_sid;
 103                 struct isis_lan_adj_sid *ladj_sid;
 104         } u;
 105
 106         /* Back pointer to IS-IS adjacency. */
 107         struct isis_adjacency *adj;
 108 };
 109
 110 /* SID type. NOTE: these values must be in sync with the YANG module. */
 111 enum sr_sid_value_type {
 112         SR_SID_VALUE_TYPE_INDEX = 0,
 113         SR_SID_VALUE_TYPE_ABSOLUTE = 1,
 114 };
 115
 116 #define IS_SID_VALUE(flag) CHECK_FLAG(flag, ISIS_PREFIX_SID_VALUE)
 117
 118 /* Last Hop Behavior. NOTE: these values must be in sync with the YANG module */
 119 enum sr_last_hop_behavior {
 120         SR_LAST_HOP_BEHAVIOR_EXP_NULL = 0,
 121         SR_LAST_HOP_BEHAVIOR_NO_PHP = 1,
 122         SR_LAST_HOP_BEHAVIOR_PHP = 2,
 123 };
 124
 125 /* Segment Routing Prefix-SID configuration. */
 126 struct sr_prefix_cfg {
 127         /* SRDB RB-tree entry. */
 128         struct srdb_prefix_cfg_item entry;
 129
 130         /* IP prefix. */
 131         struct prefix prefix;
 132
 133         /* SID value. */
 134         uint32_t sid;
 135
 136         /* SID value type. */
 137         enum sr_sid_value_type sid_type;
 138
 139         /* SID last hop behavior. */
 140         enum sr_last_hop_behavior last_hop_behavior;
 141
 142         /* Indicates whether the node flag must be explicitly unset. */
 143         bool n_flag_clear;
 144
 145         /* Does this Prefix-SID refer to a loopback address (Node-SID)? */
 146         bool node_sid;
 147
 148         /* Backpointer to IS-IS area. */
 149         struct isis_area *area;
 150 };
 151
 152 /* Per-area IS-IS Segment Routing Data Base (SRDB). */
 153 struct isis_sr_db {
 154         /* Global Operational status of Segment Routing. */
 155         bool enabled;
 156
 157         /* Thread timer to start Label Manager */
 158         struct thread *t_start_lm;
 159
 160         /* List of local Adjacency-SIDs. */
 161         struct list *adj_sids;
 162
 163         /* Management of SRLB & SRGB allocation */
 164         struct sr_local_block srlb;
 165         bool srgb_active;
 166
 167         /* Area Segment Routing configuration. */
 168         struct {
 169                 /* Administrative status of Segment Routing. */
 170                 bool enabled;
 171
 172                 /* Segment Routing Global Block lower & upper bound. */
 173                 uint32_t srgb_lower_bound;
 174                 uint32_t srgb_upper_bound;
 175
 176                 /* Segment Routing Local Block lower & upper bound. */
 177                 uint32_t srlb_lower_bound;
 178                 uint32_t srlb_upper_bound;
 179
 180                 /* Maximum SID Depth supported by the node. */
 181                 uint8_t msd;
 182
 183                 /* Prefix-SID mappings. */
 184                 struct srdb_prefix_cfg_head prefix_sids;
 185         } config;
 186 };
 187
 188 /* Prototypes. */
 189 extern struct isis_sr_block *isis_sr_find_srgb(struct lspdb_head *lspdb,
 190                                                const uint8_t *sysid);
 191 extern mpls_label_t sr_prefix_in_label(struct isis_area *area,
 192                                        struct isis_prefix_sid *psid,
 193                                        bool local);
 194 extern mpls_label_t sr_prefix_out_label(struct lspdb_head *lspdb, int family,
 195                                         struct isis_prefix_sid *psid,
 196                                         const uint8_t *nh_sysid, bool last_hop);
 197 extern int isis_sr_cfg_srgb_update(struct isis_area *area, uint32_t lower_bound,
 198                                    uint32_t upper_bound);
 199 extern int isis_sr_cfg_srlb_update(struct isis_area *area, uint32_t lower_bound,
 200                                    uint32_t upper_bound);
 201 extern struct sr_prefix_cfg *
 202 isis_sr_cfg_prefix_add(struct isis_area *area, const struct prefix *prefix);
 203 extern void isis_sr_cfg_prefix_del(struct sr_prefix_cfg *pcfg);
 204 extern struct sr_prefix_cfg *
 205 isis_sr_cfg_prefix_find(struct isis_area *area, union prefixconstptr prefix);
 206 extern void isis_sr_prefix_cfg2subtlv(const struct sr_prefix_cfg *pcfg,
 207                                       bool external,
 208                                       struct isis_prefix_sid *psid);
 209 extern void sr_adj_sid_add_single(struct isis_adjacency *adj, int family,
 210                                   bool backup, struct list *nexthops);
 211 extern struct sr_adjacency *isis_sr_adj_sid_find(struct isis_adjacency *adj,
 212                                                  int family,
 213                                                  enum sr_adj_type type);
 214 extern void isis_area_delete_backup_adj_sids(struct isis_area *area, int level);
 215 extern char *sr_op2str(char *buf, size_t size, mpls_label_t label_in,
 216                        mpls_label_t label_out);
 217 extern int isis_sr_start(struct isis_area *area);
 218 extern void isis_sr_stop(struct isis_area *area);
 219 extern void isis_sr_area_init(struct isis_area *area);
 220 extern void isis_sr_area_term(struct isis_area *area);
 221 extern void isis_sr_init(void);
 222 extern void isis_sr_term(void);
 223
 224 #endif /* _FRR_ISIS_SR_H */