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
  57 /* Segment Routing Data Base (SRDB) RB-Tree structure */
  58 PREDECL_RBTREE_UNIQ(srdb_node)
  59 PREDECL_RBTREE_UNIQ(srdb_node_prefix)
  60 PREDECL_RBTREE_UNIQ(srdb_area_prefix)
  61 PREDECL_RBTREE_UNIQ(srdb_prefix_cfg)
  62
  63 /* Segment Routing Adjacency-SID type. */
  64 enum sr_adj_type {
  65         ISIS_SR_ADJ_NORMAL = 0,
  66         ISIS_SR_LAN_BACKUP,
  67 };
  68
  69 /* Segment Routing Adjacency. */
  70 struct sr_adjacency {
  71         /* Adjacency type. */
  72         enum sr_adj_type type;
  73
  74         /* Adjacency-SID nexthop information. */
  75         struct {
  76                 int family;
  77                 union g_addr address;
  78                 mpls_label_t label;
  79         } nexthop;
  80
  81         /* (LAN-)Adjacency-SID Sub-TLV. */
  82         union {
  83                 struct isis_adj_sid *adj_sid;
  84                 struct isis_lan_adj_sid *ladj_sid;
  85         } u;
  86
  87         /* Back pointer to IS-IS adjacency. */
  88         struct isis_adjacency *adj;
  89 };
  90
  91 /* Segment Routing Prefix-SID type. */
  92 enum sr_prefix_type {
  93         ISIS_SR_PREFIX_LOCAL = 0,
  94         ISIS_SR_PREFIX_REMOTE,
  95 };
  96
  97 /* Segment Routing Nexthop Information. */
  98 struct sr_nexthop_info {
  99         mpls_label_t label;
 100         time_t uptime;
 101 };
 102
 103 /* State of Object (SR-Node and SR-Prefix) stored in SRDB */
 104 enum srdb_state {
 105         SRDB_STATE_VALIDATED = 0,
 106         SRDB_STATE_NEW,
 107         SRDB_STATE_MODIFIED,
 108         SRDB_STATE_UNCHANGED
 109 };
 110
 111 /* Segment Routing Prefix-SID. */
 112 struct sr_prefix {
 113         /* SRDB RB-tree entries. */
 114         struct srdb_node_prefix_item node_entry;
 115         struct srdb_area_prefix_item area_entry;
 116
 117         /* IP prefix. */
 118         struct prefix prefix;
 119
 120         /* SID value, algorithm and flags subTLVs. */
 121         struct isis_prefix_sid sid;
 122
 123         /* Input label value. */
 124         mpls_label_t input_label;
 125
 126         /* Prefix-SID type. */
 127         enum sr_prefix_type type;
 128         union {
 129                 struct {
 130                         /* Information about this local Prefix-SID. */
 131                         struct sr_nexthop_info info;
 132                 } local;
 133                 struct {
 134                         /* Route associated to this remote Prefix-SID. */
 135                         struct isis_route_info *rinfo;
 136                 } remote;
 137         } u;
 138
 139         /* Backpointer to Segment Routing node. */
 140         struct sr_node *srn;
 141
 142         /* SR-Prefix State used while the LSPDB is being parsed. */
 143         enum srdb_state state;
 144 };
 145
 146 /* Segment Routing node. */
 147 struct sr_node {
 148         /* SRDB RB-tree entry. */
 149         struct srdb_node_item entry;
 150
 151         /* IS-IS level: ISIS_LEVEL1 or ISIS_LEVEL2. */
 152         int level;
 153
 154         /* IS-IS node identifier. */
 155         uint8_t sysid[ISIS_SYS_ID_LEN];
 156
 157         /* Segment Routing node capabilities (SRGB, SR Algorithms) subTLVs. */
 158         struct isis_router_cap cap;
 159
 160         /* List of Prefix-SIDs advertised by this node. */
 161         struct srdb_node_prefix_head prefix_sids;
 162
 163         /* Backpointer to IS-IS area. */
 164         struct isis_area *area;
 165
 166         /* SR-Node State used while the LSPDB is being parsed. */
 167         enum srdb_state state;
 168 };
 169
 170 /* SID type. NOTE: these values must be in sync with the YANG module. */
 171 enum sr_sid_value_type {
 172         SR_SID_VALUE_TYPE_INDEX = 0,
 173         SR_SID_VALUE_TYPE_ABSOLUTE = 1,
 174 };
 175
 176 #define IS_SID_VALUE(flag) CHECK_FLAG(flag, ISIS_PREFIX_SID_VALUE)
 177
 178 /* Last Hop Behavior. NOTE: these values must be in sync with the YANG module */
 179 enum sr_last_hop_behavior {
 180         SR_LAST_HOP_BEHAVIOR_EXP_NULL = 0,
 181         SR_LAST_HOP_BEHAVIOR_NO_PHP = 1,
 182         SR_LAST_HOP_BEHAVIOR_PHP = 2,
 183 };
 184
 185 /* Segment Routing Prefix-SID configuration. */
 186 struct sr_prefix_cfg {
 187         /* SRDB RB-tree entry. */
 188         struct srdb_prefix_cfg_item entry;
 189
 190         /* IP prefix. */
 191         struct prefix prefix;
 192
 193         /* SID value. */
 194         uint32_t sid;
 195
 196         /* SID value type. */
 197         enum sr_sid_value_type sid_type;
 198
 199         /* SID last hop behavior. */
 200         enum sr_last_hop_behavior last_hop_behavior;
 201
 202         /* Does this Prefix-SID refer to a loopback address (Node-SID)? */
 203         bool node_sid;
 204
 205         /* Backpointer to IS-IS area. */
 206         struct isis_area *area;
 207 };
 208
 209 /* Per-area IS-IS Segment Routing Data Base (SRDB). */
 210 struct isis_sr_db {
 211         /* Global Operational status of Segment Routing. */
 212         bool enabled;
 213
 214         /* List of local Adjacency-SIDs. */
 215         struct list *adj_sids;
 216
 217         /* Segment Routing Node information per IS-IS level. */
 218         struct srdb_node_head sr_nodes[ISIS_LEVELS];
 219
 220         /* Segment Routing Prefix-SIDs per IS-IS level. */
 221         struct srdb_area_prefix_head prefix_sids[ISIS_LEVELS];
 222
 223         /* Area Segment Routing configuration. */
 224         struct {
 225                 /* Administrative status of Segment Routing. */
 226                 bool enabled;
 227
 228                 /* Segment Routing Global Block lower & upper bound. */
 229                 uint32_t srgb_lower_bound;
 230                 uint32_t srgb_upper_bound;
 231
 232                 /* Maximum SID Depth supported by the node. */
 233                 uint8_t msd;
 234
 235                 /* Prefix-SID mappings. */
 236                 struct srdb_prefix_cfg_head prefix_sids;
 237         } config;
 238 };
 239
 240 /* Prototypes. */
 241 extern int isis_sr_cfg_srgb_update(struct isis_area *area, uint32_t lower_bound,
 242                                    uint32_t upper_bound);
 243 extern struct sr_prefix_cfg *
 244 isis_sr_cfg_prefix_add(struct isis_area *area, const struct prefix *prefix);
 245 extern void isis_sr_cfg_prefix_del(struct sr_prefix_cfg *pcfg);
 246 extern struct sr_prefix_cfg *
 247 isis_sr_cfg_prefix_find(struct isis_area *area, union prefixconstptr prefix);
 248 extern void isis_sr_prefix_cfg2subtlv(const struct sr_prefix_cfg *pcfg,
 249                                       bool external,
 250                                       struct isis_prefix_sid *psid);
 251 extern void isis_sr_nexthop_update(struct sr_nexthop_info *srnh,
 252                                    mpls_label_t label);
 253 extern void isis_sr_nexthop_reset(struct sr_nexthop_info *srnh);
 254 extern void isis_area_verify_sr(struct isis_area *area);
 255 extern int isis_sr_start(struct isis_area *area);
 256 extern void isis_sr_stop(struct isis_area *area);
 257 extern void isis_sr_area_init(struct isis_area *area);
 258 extern void isis_sr_area_term(struct isis_area *area);
 259 extern void isis_sr_init(void);
 260 extern void isis_sr_term(void);
 261
 262 #endif /* _FRR_ISIS_SR_H */