diff options
| -rw-r--r-- | doc/bird.sgml | 29 | ||||
| -rw-r--r-- | proto/bgp/attrs.c | 69 | ||||
| -rw-r--r-- | proto/bgp/bgp.c | 22 | ||||
| -rw-r--r-- | proto/bgp/bgp.h | 17 | ||||
| -rw-r--r-- | proto/bgp/config.Y | 16 | ||||
| -rw-r--r-- | proto/bgp/packets.c | 46 |
6 files changed, 193 insertions, 6 deletions
diff --git a/doc/bird.sgml b/doc/bird.sgml index a4d7cb0c..c29353fc 100644 --- a/doc/bird.sgml +++ b/doc/bird.sgml @@ -2379,6 +2379,7 @@ avoid routing loops. <item> <rfc id="8203"> - BGP Administrative Shutdown Communication <item> <rfc id="8212"> - Default EBGP Route Propagation Behavior without Policies <item> <rfc id="9117"> - Revised Validation Procedure for BGP Flow Specifications +<item> <rfc id="9234"> - Route Leak Prevention and Detection Using Roles </itemize> <sect1>Route selection rules @@ -2819,6 +2820,29 @@ using the following configuration parameters: protocol itself (for example, if a route is received through eBGP and therefore does not have such attribute). Default: 100 (0 in pre-1.2.0 versions of BIRD). + + <tag><label id="bgp-local-role">local role <m/role-name/</tag> + BGP roles are a mechanism for route leak prevention and automatic route + filtering based on common BGP topology relationships. They are defined + in <rfc id="9234">. Instead of manually configuring filters and + communities, automatic filtering is done with the help of the OTC + attribute - a flag for routes that should be sent only to customers. + The same attribute is also used to automatically detect and filter route + leaks created by third parties. + + This option is valid for EBGP sessions, but it is not recommended to be + used within AS confederations (which would require manual filtering of + <cf/bgp_otc/ attribute on confederation boundaries). + + Possible <cf><m/role-name/</cf> values are: <cf/provider/, + <cf/rs_server/, <cf/rs_client/, <cf/customer/ and <cf/peer/. + Default: No local role assigned. + + <tag><label id="bgp-require-roles">require roles <m/switch/</tag> + If this option is set, the BGP roles must be defined on both sides, + otherwise the session will not be established. This behavior is defined + in <rfc id="9234"> as "strict mode" and is used to enforce corresponding + configuration at your conterpart side. Default: disabled. </descrip> <sect1>Channel configuration @@ -3126,6 +3150,11 @@ some of them (marked with `<tt/O/') are optional. This attribute contains accumulated IGP metric, which is a total distance to the destination through multiple autonomous systems. Currently, the attribute is not accessible from filters. + + <tag><label id="bgp-otc">int bgp_otc [O]</tag> + This attribute is defined in <rfc id="9234">. OTC is a flag that marks + routes that should be sent only to customers. If <ref id="bgp-role" + name="local Role"> is configured it set automatically. </descrip> <sect1>Example diff --git a/proto/bgp/attrs.c b/proto/bgp/attrs.c index a1f5791a..91487fae 100644 --- a/proto/bgp/attrs.c +++ b/proto/bgp/attrs.c @@ -939,6 +939,18 @@ bgp_decode_large_community(struct bgp_parse_state *s, uint code UNUSED, uint fla bgp_set_attr_ptr(to, BA_LARGE_COMMUNITY, flags, ad); } + +static void +bgp_decode_otc(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data UNUSED, uint len, ea_list **to) +{ + if (len != 4) + WITHDRAW(BAD_LENGTH, "OTC", len); + + u32 val = get_u32(data); + bgp_set_attr_u32(to, BA_ONLY_TO_CUSTOMER, flags, val); +} + + static void bgp_export_mpls_label_stack(struct bgp_export_state *s, eattr *a) { @@ -1175,6 +1187,13 @@ static union bgp_attr_desc bgp_attr_table[BGP_ATTR_MAX] = { .encode = bgp_encode_u32s, .decode = bgp_decode_large_community, }, + [BA_ONLY_TO_CUSTOMER] = { + .name = "otc", + .type = T_INT, + .flags = BAF_OPTIONAL | BAF_TRANSITIVE, + .encode = bgp_encode_u32, + .decode = bgp_decode_otc, + }, [BA_MPLS_LABEL_STACK] = { .name = "bgp_mpls_label_stack", .type = T_CLIST, @@ -1504,6 +1523,29 @@ bgp_finish_attrs(struct bgp_parse_state *s, ea_list **to) REPORT("Discarding AIGP attribute received on non-AIGP session"); bgp_unset_attr(to, BA_AIGP); } + + /* Handle OTC ingress procedure, RFC 9234 */ + if (bgp_channel_is_role_applicable(s->channel)) + { + struct bgp_proto *p = s->proto; + eattr *e = bgp_find_attr(*to, BA_ONLY_TO_CUSTOMER); + + /* Reject routes from downstream if they are leaked */ + if (e && (p->cf->local_role == BGP_ROLE_PROVIDER || + p->cf->local_role == BGP_ROLE_RS_SERVER)) + WITHDRAW("Route leak detected - OTC attribute from downstream"); + + /* Reject routes from peers if they are leaked */ + if (e && (p->cf->local_role == BGP_ROLE_PEER) && (e->u.data != p->cf->remote_as)) + WITHDRAW("Route leak detected - OTC attribute with mismatched ASN (%u)", + (uint) e->u.data); + + /* Mark routes from upstream if it did not happened before */ + if (!e && (p->cf->local_role == BGP_ROLE_CUSTOMER || + p->cf->local_role == BGP_ROLE_PEER || + p->cf->local_role == BGP_ROLE_RS_CLIENT)) + bgp_set_attr_u32(to, BA_ONLY_TO_CUSTOMER, 0, p->cf->remote_as); + } } @@ -1959,6 +2001,7 @@ bgp_setup_out_table(struct bgp_channel *c) int bgp_preexport(struct channel *C, rte *e) { + struct bgp_channel *c = (struct bgp_channel *) C; struct bgp_proto *p = (struct bgp_proto *) C->proto; struct bgp_proto *src = bgp_rte_proto(e); @@ -2000,11 +2043,11 @@ bgp_preexport(struct channel *C, rte *e) } /* Handle well-known communities, RFC 1997 */ - struct eattr *com; + struct eattr *a; if (p->cf->interpret_communities && - (com = ea_find(e->attrs, BGP_EA_ID(BA_COMMUNITY)))) + (a = bgp_find_attr(e->attrs, BA_COMMUNITY))) { - const struct adata *d = com->u.ptr; + const struct adata *d = a->u.ptr; /* Do not export anywhere */ if (int_set_contains(d, BGP_COMM_NO_ADVERTISE)) @@ -2023,6 +2066,16 @@ bgp_preexport(struct channel *C, rte *e) return -1; } + /* Do not export routes marked with OTC to upstream, RFC 9234 */ + if (bgp_channel_is_role_applicable(c)) + { + a = bgp_find_attr(e->attrs, BA_ONLY_TO_CUSTOMER); + if (a && (p->cf->local_role==BGP_ROLE_CUSTOMER || + p->cf->local_role==BGP_ROLE_PEER || + p->cf->local_role==BGP_ROLE_RS_CLIENT)) + return -1; + } + return 0; } @@ -2131,6 +2184,16 @@ bgp_update_attrs(struct bgp_proto *p, struct bgp_channel *c, rte *e, ea_list *at } } + /* Mark routes for downstream with OTC, RFC 9234 */ + if (bgp_channel_is_role_applicable(c)) + { + a = bgp_find_attr(attrs, BA_ONLY_TO_CUSTOMER); + if (!a && (p->cf->local_role == BGP_ROLE_PROVIDER || + p->cf->local_role == BGP_ROLE_PEER || + p->cf->local_role == BGP_ROLE_RS_SERVER)) + bgp_set_attr_u32(&attrs, BA_ONLY_TO_CUSTOMER, 0, p->public_as); + } + /* * Presence of mandatory attributes ORIGIN and AS_PATH is ensured by above * conditions. Presence and validity of quasi-mandatory NEXT_HOP attribute diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c index 65673e37..68c788ea 100644 --- a/proto/bgp/bgp.c +++ b/proto/bgp/bgp.c @@ -102,6 +102,7 @@ * RFC 8212 - Default EBGP Route Propagation Behavior without Policies * RFC 8654 - Extended Message Support for BGP * RFC 9117 - Revised Validation Procedure for BGP Flow Specifications + * RFC 9234 - Route Leak Prevention and Detection Using Roles * draft-ietf-idr-ext-opt-param-07 * draft-uttaro-idr-bgp-persistence-04 * draft-walton-bgp-hostname-capability-02 @@ -2020,6 +2021,15 @@ bgp_postconfig(struct proto_config *CF) if (internal && cf->rs_client) cf_error("Only external neighbor can be RS client"); + if (internal && (cf->local_role != BGP_ROLE_UNDEFINED)) + cf_error("Local role cannot be set on IBGP sessions"); + + if (interior && (cf->local_role != BGP_ROLE_UNDEFINED)) + log(L_WARN "BGP roles are not recommended to be used within AS confederations"); + + if (cf->require_roles && (cf->local_role == BGP_ROLE_UNDEFINED)) + cf_error("Local role must be set if roles are required"); + if (!cf->confederation && cf->confederation_member) cf_error("Confederation ID must be set for member sessions"); @@ -2382,6 +2392,15 @@ bgp_show_afis(int code, char *s, u32 *afis, uint count) cli_msg(code, b.start); } +static const char * +bgp_format_role_name(u8 role) +{ + static const char *bgp_role_names[] = { "provider", "rs_server", "rs_client", "customer", "peer" }; + if (role == BGP_ROLE_UNDEFINED) return "undefined"; + if (role < ARRAY_SIZE(bgp_role_names)) return bgp_role_names[role]; + return "?"; +} + static void bgp_show_capabilities(struct bgp_proto *p UNUSED, struct bgp_caps *caps) { @@ -2510,6 +2529,9 @@ bgp_show_capabilities(struct bgp_proto *p UNUSED, struct bgp_caps *caps) if (caps->hostname) cli_msg(-1006, " Hostname: %s", caps->hostname); + + if (caps->role != BGP_ROLE_UNDEFINED) + cli_msg(-1006, " Role: %s", bgp_format_role_name(caps->role)); } static void diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h index fdd134f4..0cd327a2 100644 --- a/proto/bgp/bgp.h +++ b/proto/bgp/bgp.h @@ -113,6 +113,8 @@ struct bgp_config { int gr_mode; /* Graceful restart mode (BGP_GR_*) */ int llgr_mode; /* Long-lived graceful restart mode (BGP_LLGR_*) */ int setkey; /* Set MD5 password to system SA/SP database */ + u8 local_role; /* Set peering role with neighbor [RFC 9234] */ + int require_roles; /* Require configured roles on both sides */ /* Times below are in seconds */ unsigned gr_time; /* Graceful restart timeout */ unsigned llgr_time; /* Long-lived graceful restart stale time */ @@ -166,6 +168,13 @@ struct bgp_channel_config { #define BGP_PT_INTERNAL 1 #define BGP_PT_EXTERNAL 2 +#define BGP_ROLE_UNDEFINED 255 +#define BGP_ROLE_PROVIDER 0 +#define BGP_ROLE_RS_SERVER 1 +#define BGP_ROLE_RS_CLIENT 2 +#define BGP_ROLE_CUSTOMER 3 +#define BGP_ROLE_PEER 4 + #define NH_NO 0 #define NH_ALL 1 #define NH_IBGP 2 @@ -226,6 +235,7 @@ struct bgp_caps { u8 ext_messages; /* Extended message length, RFC draft */ u8 route_refresh; /* Route refresh capability, RFC 2918 */ u8 enhanced_refresh; /* Enhanced route refresh, RFC 7313 */ + u8 role; /* BGP role capability, RFC 9234 */ u8 gr_aware; /* Graceful restart capability, RFC 4724 */ u8 gr_flags; /* Graceful restart flags */ @@ -500,6 +510,12 @@ static inline int bgp_cc_is_ipv4(struct bgp_channel_config *c) static inline int bgp_cc_is_ipv6(struct bgp_channel_config *c) { return BGP_AFI(c->afi) == BGP_AFI_IPV6; } +static inline int bgp_channel_is_role_applicable(struct bgp_channel *c) +{ return (c->afi == BGP_AF_IPV4 || c->afi == BGP_AF_IPV6); } + +static inline int bgp_cc_is_role_applicable(struct bgp_channel_config *c) +{ return (c->afi == BGP_AF_IPV4 || c->afi == BGP_AF_IPV6); } + static inline uint bgp_max_packet_length(struct bgp_conn *conn) { return conn->ext_messages ? BGP_MAX_EXT_MSG_LENGTH : BGP_MAX_MESSAGE_LENGTH; } @@ -667,6 +683,7 @@ enum bgp_attr_id { BA_AS4_AGGREGATOR = 0x12, /* RFC 6793 */ BA_AIGP = 0x1a, /* RFC 7311 */ BA_LARGE_COMMUNITY = 0x20, /* RFC 8092 */ +#define BA_ONLY_TO_CUSTOMER 0x23 /* RFC 9234 */ /* Bird's private internal BGP attributes */ BA_MPLS_LABEL_STACK = 0x100, /* MPLS label stack transfer attribute */ diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y index 24f3ec8f..9f0d2306 100644 --- a/proto/bgp/config.Y +++ b/proto/bgp/config.Y @@ -30,7 +30,8 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE, STRICT, BIND, CONFEDERATION, MEMBER, MULTICAST, FLOW4, FLOW6, LONG, LIVED, STALE, IMPORT, IBGP, EBGP, MANDATORY, INTERNAL, EXTERNAL, SETS, DYNAMIC, RANGE, NAME, DIGITS, AIGP, ORIGINATE, COST, ENFORCE, - FIRST, FREE, VALIDATE, BASE) + FIRST, FREE, VALIDATE, BASE, ROLE, ROLES, PEER, PROVIDER, CUSTOMER, + RS_SERVER, RS_CLIENT, REQUIRE, BGP_OTC) %type <i> bgp_nh %type <i32> bgp_afi @@ -39,7 +40,7 @@ CF_KEYWORDS(CEASE, PREFIX, LIMIT, HIT, ADMINISTRATIVE, SHUTDOWN, RESET, PEER, CONFIGURATION, CHANGE, DECONFIGURED, CONNECTION, REJECTED, COLLISION, OUT, OF, RESOURCES) -%type<i> bgp_cease_mask bgp_cease_list bgp_cease_flag +%type<i> bgp_cease_mask bgp_cease_list bgp_cease_flag bgp_role_name CF_GRAMMAR @@ -73,6 +74,7 @@ bgp_proto_start: proto_start BGP { BGP_CFG->llgr_mode = -1; BGP_CFG->llgr_time = 3600; BGP_CFG->setkey = 1; + BGP_CFG->local_role = BGP_ROLE_UNDEFINED; BGP_CFG->dynamic_name = "dynbgp"; BGP_CFG->check_link = -1; } @@ -115,6 +117,14 @@ bgp_cease_flag: | OUT OF RESOURCES { $$ = 1 << 8; } ; +bgp_role_name: + PEER { $$ = BGP_ROLE_PEER; } + | PROVIDER { $$ = BGP_ROLE_PROVIDER; } + | CUSTOMER { $$ = BGP_ROLE_CUSTOMER; } + | RS_SERVER { $$ = BGP_ROLE_RS_SERVER; } + | RS_CLIENT { $$ = BGP_ROLE_RS_CLIENT; } + ; + bgp_proto: bgp_proto_start proto_name '{' | bgp_proto proto_item ';' @@ -198,6 +208,8 @@ bgp_proto: | bgp_proto BFD GRACEFUL ';' { init_bfd_opts(&BGP_CFG->bfd); BGP_CFG->bfd->mode = BGP_BFD_GRACEFUL; } | bgp_proto BFD { open_bfd_opts(&BGP_CFG->bfd); } bfd_opts { close_bfd_opts(); } ';' | bgp_proto ENFORCE FIRST AS bool ';' { BGP_CFG->enforce_first_as = $5; } + | bgp_proto LOCAL ROLE bgp_role_name ';' { BGP_CFG->local_role = $4; } + | bgp_proto REQUIRE ROLES bool ';' { BGP_CFG->require_roles = $4; } ; bgp_afi: diff --git a/proto/bgp/packets.c b/proto/bgp/packets.c index 1f208432..d4d2d0b0 100644 --- a/proto/bgp/packets.c +++ b/proto/bgp/packets.c @@ -238,6 +238,7 @@ bgp_prepare_capabilities(struct bgp_conn *conn) caps->ext_messages = p->cf->enable_extended_messages; caps->route_refresh = p->cf->enable_refresh; caps->enhanced_refresh = p->cf->enable_refresh; + caps->role = p->cf->local_role; if (caps->as4_support) caps->as4_number = p->public_as; @@ -350,6 +351,13 @@ bgp_write_capabilities(struct bgp_conn *conn, byte *buf) *buf++ = 0; /* Capability data length */ } + if (caps->role != BGP_ROLE_UNDEFINED) + { + *buf++ = 9; /* Capability 9: Announce chosen BGP role */ + *buf++ = 1; /* Capability data length */ + *buf++ = caps->role; + } + if (caps->gr_aware) { *buf++ = 64; /* Capability 64: Support for graceful restart */ @@ -449,11 +457,15 @@ bgp_read_capabilities(struct bgp_conn *conn, byte *pos, int len) struct bgp_proto *p = conn->bgp; struct bgp_caps *caps; struct bgp_af_caps *ac; + uint err_subcode = 0; int i, cl; u32 af; if (!conn->remote_caps) + { caps = mb_allocz(p->p.pool, sizeof(struct bgp_caps) + sizeof(struct bgp_af_caps)); + caps->role = BGP_ROLE_UNDEFINED; + } else { caps = conn->remote_caps; @@ -513,6 +525,21 @@ bgp_read_capabilities(struct bgp_conn *conn, byte *pos, int len) caps->ext_messages = 1; break; + case 9: /* BGP role capability, RFC 9234 */ + if (cl != 1) + goto err; + + /* Reserved value */ + if (pos[2] == BGP_ROLE_UNDEFINED) + { err_subcode = 11; goto err; } + + /* Multiple inconsistent values */ + if ((caps->role != BGP_ROLE_UNDEFINED) && (caps->role != pos[2])) + { err_subcode = 11; goto err; } + + caps->role = pos[2]; + break; + case 64: /* Graceful restart capability, RFC 4724 */ if (cl % 4 != 2) goto err; @@ -638,7 +665,7 @@ bgp_read_capabilities(struct bgp_conn *conn, byte *pos, int len) err: mb_free(caps); - bgp_error(conn, 2, 0, NULL, 0); + bgp_error(conn, 2, err_subcode, NULL, 0); return -1; } @@ -854,6 +881,22 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, uint len) conn->received_as = asn; } + /* RFC 9234 4.2 - check role agreement */ + u8 local_role = p->cf->local_role; + u8 neigh_role = caps->role; + + if ((local_role != BGP_ROLE_UNDEFINED) && + (neigh_role != BGP_ROLE_UNDEFINED) && + !((local_role == BGP_ROLE_PEER && neigh_role == BGP_ROLE_PEER) || + (local_role == BGP_ROLE_CUSTOMER && neigh_role == BGP_ROLE_PROVIDER) || + (local_role == BGP_ROLE_PROVIDER && neigh_role == BGP_ROLE_CUSTOMER) || + (local_role == BGP_ROLE_RS_CLIENT && neigh_role == BGP_ROLE_RS_SERVER) || + (local_role == BGP_ROLE_RS_SERVER && neigh_role == BGP_ROLE_RS_CLIENT))) + { bgp_error(conn, 2, 11, NULL, 0); return; } + + if ((p->cf->require_roles) && (neigh_role == BGP_ROLE_UNDEFINED)) + { bgp_error(conn, 2, 11, NULL, 0); return; } + /* Check the other connection */ other = (conn == &p->outgoing_conn) ? &p->incoming_conn : &p->outgoing_conn; switch (other->state) @@ -2977,6 +3020,7 @@ static struct { { 2, 6, "Unacceptable hold time" }, { 2, 7, "Required capability missing" }, /* [RFC5492] */ { 2, 8, "No supported AFI/SAFI" }, /* This error msg is nonstandard */ + { 2,11, "Role mismatch" }, /* From Open Policy, RFC 9234 */ { 3, 0, "Invalid UPDATE message" }, { 3, 1, "Malformed attribute list" }, { 3, 2, "Unrecognized well-known attribute" }, |