diff options
Diffstat (limited to 'lib/route.h')
| -rw-r--r-- | lib/route.h | 549 |
1 files changed, 549 insertions, 0 deletions
diff --git a/lib/route.h b/lib/route.h new file mode 100644 index 00000000..f5456396 --- /dev/null +++ b/lib/route.h @@ -0,0 +1,549 @@ +/* + * BIRD Internet Routing Daemon -- Routing data structures + * + * (c) 1998--2000 Martin Mares <mj@ucw.cz> + * (c) 2022 Maria Matejka <mq@jmq.cz> + * + * Can be freely distributed and used under the terms of the GNU GPL. + */ + +#ifndef _BIRD_LIB_ROUTE_H_ +#define _BIRD_LIB_ROUTE_H_ + +#undef RT_SOURCE_DEBUG + +#include "lib/type.h" +#include "lib/rcu.h" +#include "lib/hash.h" +#include "lib/event.h" + +struct network; +struct proto; +struct cli; +struct rtable; + +typedef struct rte { + struct ea_list *attrs; /* Attributes of this route */ + const net_addr *net; /* Network this RTE belongs to */ + struct rte_src *src; /* Route source that created the route */ + struct rt_import_hook *sender; /* Import hook used to send the route to the routing table */ + btime lastmod; /* Last modified (set by table) */ + u32 id; /* Table specific route id */ + byte flags; /* Table-specific flags */ + byte pflags; /* Protocol-specific flags */ + u8 generation; /* If this route import is based on other previously exported route, + this value should be 1 + MAX(generation of the parent routes). + Otherwise the route is independent and this value is zero. */ + u8 stale_cycle; /* Auxiliary value for route refresh */ +} rte; + +#define REF_FILTERED 2 /* Route is rejected by import filter */ +#define REF_PENDING 32 /* Route has not propagated completely yet */ + +/* Route is valid for propagation (may depend on other flags in the future), accepts NULL */ +static inline int rte_is_valid(rte *r) { return r && !(r->flags & REF_FILTERED); } + +/* Route just has REF_FILTERED flag */ +static inline int rte_is_filtered(rte *r) { return !!(r->flags & REF_FILTERED); } + +struct rte_src { + struct rte_src *next; /* Hash chain */ + struct rte_owner *owner; /* Route source owner */ + u32 private_id; /* Private ID, assigned by the protocol */ + u32 global_id; /* Globally unique ID of the source */ + _Atomic u64 uc; /* Use count */ +}; + +struct rte_owner_class { + void (*get_route_info)(struct rte *, byte *buf); /* Get route information (for `show route' command) */ + int (*rte_better)(struct rte *, struct rte *); + int (*rte_mergable)(struct rte *, struct rte *); + u32 (*rte_igp_metric)(const rte *); +}; + +struct rte_owner { + struct rte_owner_class *class; + int (*rte_recalculate)(struct rtable *, struct network *, struct rte *, struct rte *, struct rte *); + HASH(struct rte_src) hash; + const char *name; + u32 hash_key; + u32 uc; + event_list *list; + event *prune; + event *stop; +}; + +DEFINE_DOMAIN(attrs); +extern DOMAIN(attrs) attrs_domain; + +#define RTA_LOCK LOCK_DOMAIN(attrs, attrs_domain) +#define RTA_UNLOCK UNLOCK_DOMAIN(attrs, attrs_domain) + +#define RTE_SRC_PU_SHIFT 44 +#define RTE_SRC_IN_PROGRESS (1ULL << RTE_SRC_PU_SHIFT) + +/* Get a route source. This also locks the source, therefore the caller has to + * unlock the source after the route has been propagated. */ +struct rte_src *rt_get_source_o(struct rte_owner *o, u32 id); +#define rt_get_source(p, id) rt_get_source_o(&(p)->sources, (id)) + +struct rte_src *rt_find_source_global(u32 id); + +#ifdef RT_SOURCE_DEBUG +#define rt_lock_source _rt_lock_source_internal +#define rt_unlock_source _rt_unlock_source_internal +#endif + +static inline void rt_lock_source(struct rte_src *src) +{ + /* Locking a source is trivial; somebody already holds it so we just increase + * the use count. Nothing can be freed underneath our hands. */ + u64 uc = atomic_fetch_add_explicit(&src->uc, 1, memory_order_acq_rel); + ASSERT_DIE(uc > 0); +} + +static inline void rt_unlock_source(struct rte_src *src) +{ + /* Unlocking is tricky. We do it lockless so at the same time, the prune + * event may be running, therefore if the unlock gets us to zero, it must be + * the last thing in this routine, otherwise the prune routine may find the + * source's usecount zeroed, freeing it prematurely. + * + * The usecount is split into two parts: + * the top 20 bits are an in-progress indicator + * the bottom 44 bits keep the actual usecount. + * + * Therefore at most 1 million of writers can simultaneously unlock the same + * source, while at most ~17T different routes can reference it. Both limits + * are insanely high from the 2022 point of view. Let's suppose that when 17T + * routes or 1M writers get real, we get also 128bit atomic variables in the + * C norm. */ + + /* First, we push the in-progress indicator */ + u64 uc = atomic_fetch_add_explicit(&src->uc, RTE_SRC_IN_PROGRESS, memory_order_acq_rel); + + /* Then we split the indicator to its parts. Remember, we got the value before the operation happened. */ + u64 pending = (uc >> RTE_SRC_PU_SHIFT) + 1; + uc &= RTE_SRC_IN_PROGRESS - 1; + + /* We per-use the RCU critical section indicator to make the prune event wait + * until we finish here in the rare case we get preempted. */ + rcu_read_lock(); + + /* Obviously, there can't be more pending unlocks than the usecount itself */ + if (uc == pending) + /* If we're the last unlocker, schedule the owner's prune event */ + ev_send(src->owner->list, src->owner->prune); + else + ASSERT_DIE(uc > pending); + + /* And now, finally, simultaneously pop the in-progress indicator and the + * usecount, possibly allowing the source pruning routine to free this structure */ + atomic_fetch_sub_explicit(&src->uc, RTE_SRC_IN_PROGRESS + 1, memory_order_acq_rel); + + /* ... and to reduce the load a bit, the source pruning routine will better wait for + * RCU synchronization instead of a busy loop. */ + rcu_read_unlock(); +} + +#ifdef RT_SOURCE_DEBUG +#undef rt_lock_source +#undef rt_unlock_source + +#define rt_lock_source(x) ( log(L_INFO "Lock source %uG at %s:%d", (x)->global_id, __FILE__, __LINE__), _rt_lock_source_internal(x) ) +#define rt_unlock_source(x) ( log(L_INFO "Unlock source %uG at %s:%d", (x)->global_id, __FILE__, __LINE__), _rt_unlock_source_internal(x) ) +#endif + +void rt_init_sources(struct rte_owner *, const char *name, event_list *list); +void rt_destroy_sources(struct rte_owner *, event *); + +/* + * Route Attributes + * + * Beware: All standard BGP attributes must be represented here instead + * of making them local to the route. This is needed to ensure proper + * construction of BGP route attribute lists. + */ + +/* Nexthop structure */ +struct nexthop { + ip_addr gw; /* Next hop */ + struct iface *iface; /* Outgoing interface */ + byte flags; + byte weight; + byte labels; /* Number of all labels */ + u32 label[0]; +}; + +/* For packing one into eattrs */ +struct nexthop_adata { + struct adata ad; + /* There is either a set of nexthops or a special destination (RTD_*) */ + union { + struct nexthop nh; + uint dest; + }; +}; + +#define NEXTHOP_DEST_SIZE (OFFSETOF(struct nexthop_adata, dest) + sizeof(uint) - OFFSETOF(struct adata, data)) +#define NEXTHOP_DEST_LITERAL(x) ((struct nexthop_adata) { \ + .ad.length = NEXTHOP_DEST_SIZE, .dest = (x), }) + +#define RNF_ONLINK 0x1 /* Gateway is onlink regardless of IP ranges */ + + +#define RTS_STATIC 1 /* Normal static route */ +#define RTS_INHERIT 2 /* Route inherited from kernel */ +#define RTS_DEVICE 3 /* Device route */ +#define RTS_STATIC_DEVICE 4 /* Static device route */ +#define RTS_REDIRECT 5 /* Learned via redirect */ +#define RTS_RIP 6 /* RIP route */ +#define RTS_OSPF 7 /* OSPF route */ +#define RTS_OSPF_IA 8 /* OSPF inter-area route */ +#define RTS_OSPF_EXT1 9 /* OSPF external route type 1 */ +#define RTS_OSPF_EXT2 10 /* OSPF external route type 2 */ +#define RTS_BGP 11 /* BGP route */ +#define RTS_PIPE 12 /* Inter-table wormhole */ +#define RTS_BABEL 13 /* Babel route */ +#define RTS_RPKI 14 /* Route Origin Authorization */ +#define RTS_PERF 15 /* Perf checker */ +#define RTS_MAX 16 + +#define RTD_NONE 0 /* Undefined next hop */ +#define RTD_UNICAST 1 /* A standard next hop */ +#define RTD_BLACKHOLE 2 /* Silently drop packets */ +#define RTD_UNREACHABLE 3 /* Reject as unreachable */ +#define RTD_PROHIBIT 4 /* Administratively prohibited */ +#define RTD_MAX 5 + +extern const char * rta_dest_names[RTD_MAX]; + +static inline const char *rta_dest_name(uint n) +{ return (n < RTD_MAX) ? rta_dest_names[n] : "???"; } + + +/* + * Extended Route Attributes + */ + +typedef struct eattr { + word id; /* EA_CODE(PROTOCOL_..., protocol-dependent ID) */ + byte flags; /* Protocol-dependent flags */ + byte type; /* Attribute type */ + byte rfu:5; + byte originated:1; /* The attribute has originated locally */ + byte fresh:1; /* An uncached attribute (e.g. modified in export filter) */ + byte undef:1; /* Explicitly undefined */ + + PADDING(unused, 3, 3); + + union bval u; +} eattr; + + +#define EA_CODE_MASK 0xffff +#define EA_ALLOW_UNDEF 0x10000 /* ea_find: allow EAF_TYPE_UNDEF */ +#define EA_BIT(n) ((n) << 24) /* Used in bitfield accessors */ +#define EA_BIT_GET(ea) ((ea) >> 24) + +typedef struct ea_list { + struct ea_list *next; /* In case we have an override list */ + byte flags; /* Flags: EALF_... */ + byte rfu; + word count; /* Number of attributes */ + eattr attrs[0]; /* Attribute definitions themselves */ +} ea_list; + +struct ea_storage { + struct ea_storage *next_hash; /* Next in hash chain */ + struct ea_storage **pprev_hash; /* Previous in hash chain */ + _Atomic u32 uc; /* Use count */ + u32 hash_key; /* List hash */ + ea_list l[0]; /* The list itself */ +}; + +#define EALF_SORTED 1 /* Attributes are sorted by code */ +#define EALF_BISECT 2 /* Use interval bisection for searching */ +#define EALF_CACHED 4 /* List is cached */ + +struct ea_class { +#define EA_CLASS_INSIDE \ + const char *name; /* Name (both print and filter) */ \ + struct symbol *sym; /* Symbol to export to configs */ \ + uint id; /* Autoassigned attribute ID */ \ + uint uc; /* Reference count */ \ + btype type; /* Data type ID */ \ + uint readonly:1; /* This attribute can't be changed by filters */ \ + uint conf:1; /* Requested by config */ \ + uint hidden:1; /* Technical attribute, do not show, do not expose to filters */ \ + void (*format)(const eattr *ea, byte *buf, uint size); \ + void (*stored)(const eattr *ea); /* When stored into global hash */ \ + void (*freed)(const eattr *ea); /* When released from global hash */ \ + + EA_CLASS_INSIDE; +}; + +struct ea_class_ref { + resource r; + struct ea_class *class; +}; + +void ea_register_init(struct ea_class *); +struct ea_class_ref *ea_register_alloc(pool *, struct ea_class); + +#define EA_REGISTER_ALL_HELPER(x) ea_register_init(x); +#define EA_REGISTER_ALL(...) MACRO_FOREACH(EA_REGISTER_ALL_HELPER, __VA_ARGS__) + +struct ea_class *ea_class_find_by_id(uint id); +struct ea_class *ea_class_find_by_name(const char *name); +static inline struct ea_class *ea_class_self(struct ea_class *self) { return self; } +#define ea_class_find(_arg) _Generic((_arg), \ + uint: ea_class_find_by_id, \ + word: ea_class_find_by_id, \ + char *: ea_class_find_by_name, \ + const char *: ea_class_find_by_name, \ + struct ea_class *: ea_class_self)(_arg) + +struct ea_walk_state { + ea_list *eattrs; /* Ccurrent ea_list, initially set by caller */ + eattr *ea; /* Current eattr, initially NULL */ + u32 visited[4]; /* Bitfield, limiting max to 128 */ +}; + +#define ea_find(_l, _arg) _Generic((_arg), uint: ea_find_by_id, struct ea_class *: ea_find_by_class, char *: ea_find_by_name)(_l, _arg) +eattr *ea_find_by_id(ea_list *, unsigned ea); +static inline eattr *ea_find_by_class(ea_list *l, const struct ea_class *def) +{ return ea_find_by_id(l, def->id); } +static inline eattr *ea_find_by_name(ea_list *l, const char *name) +{ + const struct ea_class *def = ea_class_find_by_name(name); + return def ? ea_find_by_class(l, def) : NULL; +} + +#define ea_get_int(_l, _ident, _def) ({ \ + struct ea_class *cls = ea_class_find((_ident)); \ + ASSERT_DIE(cls->type & EAF_EMBEDDED); \ + const eattr *ea = ea_find((_l), cls->id); \ + (ea ? ea->u.data : (_def)); \ + }) + +#define ea_get_ip(_l, _ident, _def) ({ \ + struct ea_class *cls = ea_class_find((_ident)); \ + ASSERT_DIE(cls->type == T_IP); \ + const eattr *ea = ea_find((_l), cls->id); \ + (ea ? *((const ip_addr *) ea->u.ptr->data) : (_def)); \ + }) + +eattr *ea_walk(struct ea_walk_state *s, uint id, uint max); +void ea_dump(ea_list *); +int ea_same(ea_list *x, ea_list *y); /* Test whether two ea_lists are identical */ +uint ea_hash(ea_list *e); /* Calculate 16-bit hash value */ +ea_list *ea_append(ea_list *to, ea_list *what); +void ea_format_bitfield(const struct eattr *a, byte *buf, int bufsize, const char **names, int min, int max); + +/* Normalize ea_list; allocates the result from tmp_linpool */ +ea_list *ea_normalize(ea_list *e, int overlay); + +uint ea_list_size(ea_list *); +void ea_list_copy(ea_list *dest, ea_list *src, uint size); + +#define EA_LOCAL_LIST(N) struct { ea_list l; eattr a[N]; } + +#define EA_LITERAL_EMBEDDED(_class, _flags, _val) ({ \ + btype _type = (_class)->type; \ + ASSERT_DIE(_type & EAF_EMBEDDED); \ + EA_LITERAL_GENERIC((_class)->id, _type, _flags, .u.i = _val); \ + }) + +#define EA_LITERAL_STORE_ADATA(_class, _flags, _buf, _len) ({ \ + btype _type = (_class)->type; \ + ASSERT_DIE(!(_type & EAF_EMBEDDED)); \ + EA_LITERAL_GENERIC((_class)->id, _type, _flags, .u.ad = tmp_store_adata((_buf), (_len))); \ + }) + +#define EA_LITERAL_DIRECT_ADATA(_class, _flags, _adata) ({ \ + btype _type = (_class)->type; \ + ASSERT_DIE(!(_type & EAF_EMBEDDED)); \ + EA_LITERAL_GENERIC((_class)->id, _type, _flags, .u.ad = _adata); \ + }) + +#define EA_LITERAL_GENERIC(_id, _type, _flags, ...) \ + ((eattr) { .id = _id, .type = _type, .flags = _flags, __VA_ARGS__ }) + +static inline eattr * +ea_set_attr(ea_list **to, eattr a) +{ + EA_LOCAL_LIST(1) *ea = tmp_alloc(sizeof(*ea)); + *ea = (typeof(*ea)) { + .l.flags = EALF_SORTED, + .l.count = 1, + .l.next = *to, + .a[0] = a, + }; + + *to = &ea->l; + return &ea->a[0]; +} + +static inline void +ea_unset_attr(ea_list **to, _Bool local, const struct ea_class *def) +{ + ea_set_attr(to, EA_LITERAL_GENERIC(def->id, 0, 0, + .fresh = local, .originated = local, .undef = 1)); +} + +static inline void +ea_set_attr_u32(ea_list **to, const struct ea_class *def, uint flags, u64 data) +{ ea_set_attr(to, EA_LITERAL_EMBEDDED(def, flags, data)); } + +static inline void +ea_set_attr_data(ea_list **to, const struct ea_class *def, uint flags, const void *data, uint len) +{ ea_set_attr(to, EA_LITERAL_STORE_ADATA(def, flags, data, len)); } + +static inline void +ea_copy_attr(ea_list **to, ea_list *from, const struct ea_class *def) +{ + eattr *e = ea_find_by_class(from, def); + if (e) + if (e->type & EAF_EMBEDDED) + ea_set_attr_u32(to, def, e->flags, e->u.data); + else + ea_set_attr_data(to, def, e->flags, e->u.ptr->data, e->u.ptr->length); + else + ea_unset_attr(to, 0, def); +} + +/* + * Common route attributes + */ + +/* Preference: first-order comparison */ +extern struct ea_class ea_gen_preference; +static inline u32 rt_get_preference(rte *rt) +{ return ea_get_int(rt->attrs, &ea_gen_preference, 0); } + +/* IGP metric: second-order comparison */ +extern struct ea_class ea_gen_igp_metric; +u32 rt_get_igp_metric(const rte *rt); +#define IGP_METRIC_UNKNOWN 0x80000000 /* Default igp_metric used when no other + protocol-specific metric is availabe */ + +/* From: Advertising router */ +extern struct ea_class ea_gen_from; + +/* Source: An old method to devise the route source protocol and kind. + * To be superseded in a near future by something more informative. */ +extern struct ea_class ea_gen_source; +static inline u32 rt_get_source_attr(const rte *rt) +{ return ea_get_int(rt->attrs, &ea_gen_source, 0); } + +/* Flowspec validation result */ +enum flowspec_valid { + FLOWSPEC_UNKNOWN = 0, + FLOWSPEC_VALID = 1, + FLOWSPEC_INVALID = 2, + FLOWSPEC__MAX, +}; + +extern const char * flowspec_valid_names[FLOWSPEC__MAX]; +static inline const char *flowspec_valid_name(enum flowspec_valid v) +{ return (v < FLOWSPEC__MAX) ? flowspec_valid_names[v] : "???"; } + +extern struct ea_class ea_gen_flowspec_valid; +static inline enum flowspec_valid rt_get_flowspec_valid(rte *rt) +{ return ea_get_int(rt->attrs, &ea_gen_flowspec_valid, FLOWSPEC_UNKNOWN); } + +/* Next hop: For now, stored as adata */ +extern struct ea_class ea_gen_nexthop; + +static inline void ea_set_dest(struct ea_list **to, uint flags, uint dest) +{ + struct nexthop_adata nhad = NEXTHOP_DEST_LITERAL(dest); + ea_set_attr_data(to, &ea_gen_nexthop, flags, &nhad.ad.data, nhad.ad.length); +} + +/* Next hop structures */ + +#define NEXTHOP_ALIGNMENT (_Alignof(struct nexthop)) +#define NEXTHOP_MAX_SIZE (sizeof(struct nexthop) + sizeof(u32)*MPLS_MAX_LABEL_STACK) +#define NEXTHOP_SIZE(_nh) NEXTHOP_SIZE_CNT(((_nh)->labels)) +#define NEXTHOP_SIZE_CNT(cnt) BIRD_ALIGN((sizeof(struct nexthop) + sizeof(u32) * (cnt)), NEXTHOP_ALIGNMENT) +#define nexthop_size(nh) NEXTHOP_SIZE((nh)) + +#define NEXTHOP_NEXT(_nh) ((void *) (_nh) + NEXTHOP_SIZE(_nh)) +#define NEXTHOP_END(_nhad) ((_nhad)->ad.data + (_nhad)->ad.length) +#define NEXTHOP_VALID(_nh, _nhad) ((void *) (_nh) < (void *) NEXTHOP_END(_nhad)) +#define NEXTHOP_ONE(_nhad) (NEXTHOP_NEXT(&(_nhad)->nh) == NEXTHOP_END(_nhad)) + +#define NEXTHOP_WALK(_iter, _nhad) for ( \ + struct nexthop *_iter = &(_nhad)->nh; \ + (void *) _iter < (void *) NEXTHOP_END(_nhad); \ + _iter = NEXTHOP_NEXT(_iter)) + + +static inline int nexthop_same(struct nexthop_adata *x, struct nexthop_adata *y) +{ return adata_same(&x->ad, &y->ad); } +struct nexthop_adata *nexthop_merge(struct nexthop_adata *x, struct nexthop_adata *y, int max, linpool *lp); +struct nexthop_adata *nexthop_sort(struct nexthop_adata *x, linpool *lp); +int nexthop_is_sorted(struct nexthop_adata *x); + +#define NEXTHOP_IS_REACHABLE(nhad) ((nhad)->ad.length > NEXTHOP_DEST_SIZE) + +/* Route has regular, reachable nexthop (i.e. not RTD_UNREACHABLE and like) */ +static inline int rte_is_reachable(rte *r) +{ + eattr *nhea = ea_find(r->attrs, &ea_gen_nexthop); + if (!nhea) + return 0; + + struct nexthop_adata *nhad = (void *) nhea->u.ptr; + return NEXTHOP_IS_REACHABLE(nhad); +} + +static inline int nhea_dest(eattr *nhea) +{ + if (!nhea) + return RTD_NONE; + + struct nexthop_adata *nhad = nhea ? (struct nexthop_adata *) nhea->u.ptr : NULL; + if (NEXTHOP_IS_REACHABLE(nhad)) + return RTD_UNICAST; + else + return nhad->dest; +} + +static inline int rte_dest(const rte *r) +{ + return nhea_dest(ea_find(r->attrs, &ea_gen_nexthop)); +} + +void rta_init(void); +ea_list *ea_lookup(ea_list *, int overlay); /* Get a cached (and normalized) variant of this attribute list */ +static inline int ea_is_cached(const ea_list *r) { return r->flags & EALF_CACHED; } +static inline struct ea_storage *ea_get_storage(ea_list *r) +{ + ASSERT_DIE(ea_is_cached(r)); + return SKIP_BACK(struct ea_storage, l[0], r); +} + +static inline ea_list *ea_clone(ea_list *r) { + ASSERT_DIE(0 < atomic_fetch_add_explicit(&ea_get_storage(r)->uc, 1, memory_order_acq_rel)); + return r; +} +void ea__free(struct ea_storage *r); +static inline void ea_free(ea_list *l) { + if (!l) return; + struct ea_storage *r = ea_get_storage(l); + if (1 == atomic_fetch_sub_explicit(&r->uc, 1, memory_order_acq_rel)) ea__free(r); +} + +void ea_dump(ea_list *); +void ea_dump_all(void); +void ea_show_list(struct cli *, ea_list *); + +#define rta_lookup ea_lookup +#define rta_is_cached ea_is_cached +#define rta_clone ea_clone +#define rta_free ea_free + +#endif |