/* * BIRD -- BGP Packet Processing * * (c) 2000 Martin Mares * (c) 2008--2016 Ondrej Zajicek * (c) 2008--2016 CZ.NIC z.s.p.o. * * Can be freely distributed and used under the terms of the GNU GPL. */ #undef LOCAL_DEBUG #include #include "nest/bird.h" #include "nest/iface.h" #include "nest/protocol.h" #include "nest/route.h" #include "nest/attrs.h" #include "proto/mrt/mrt.h" #include "conf/conf.h" #include "lib/unaligned.h" #include "lib/flowspec.h" #include "lib/socket.h" #include "nest/cli.h" #include "bgp.h" #define BGP_RR_REQUEST 0 #define BGP_RR_BEGIN 1 #define BGP_RR_END 2 #define BGP_NLRI_MAX (4 + 1 + 32) #define BGP_MPLS_BOS 1 /* Bottom-of-stack bit */ #define BGP_MPLS_MAX 10 /* Max number of labels that 24*n <= 255 */ #define BGP_MPLS_NULL 3 /* Implicit NULL label */ #define BGP_MPLS_MAGIC 0x800000 /* Magic withdraw label value, RFC 3107 3 */ static struct tbf rl_rcv_update = TBF_DEFAULT_LOG_LIMITS; static struct tbf rl_snd_update = TBF_DEFAULT_LOG_LIMITS; /* Table for state -> RFC 6608 FSM error subcodes */ static byte fsm_err_subcode[BS_MAX] = { [BS_OPENSENT] = 1, [BS_OPENCONFIRM] = 2, [BS_ESTABLISHED] = 3 }; static struct bgp_channel * bgp_get_channel(struct bgp_proto *p, u32 afi) { uint i; for (i = 0; i < p->channel_count; i++) if (p->afi_map[i] == afi) return p->channel_map[i]; return NULL; } static inline void put_af3(byte *buf, u32 id) { put_u16(buf, id >> 16); buf[2] = id & 0xff; } static inline void put_af4(byte *buf, u32 id) { put_u16(buf, id >> 16); buf[2] = 0; buf[3] = id & 0xff; } static inline u32 get_af3(byte *buf) { return (get_u16(buf) << 16) | buf[2]; } static inline u32 get_af4(byte *buf) { return (get_u16(buf) << 16) | buf[3]; } static void init_mrt_bgp_data(struct bgp_conn *conn, struct mrt_bgp_data *d) { struct bgp_proto *p = conn->bgp; int p_ok = conn->state >= BS_OPENCONFIRM; memset(d, 0, sizeof(struct mrt_bgp_data)); d->peer_as = p->remote_as; d->local_as = p->local_as; d->index = (p->neigh && p->neigh->iface) ? p->neigh->iface->index : 0; d->af = ipa_is_ip4(p->remote_ip) ? BGP_AFI_IPV4 : BGP_AFI_IPV6; d->peer_ip = conn->sk ? conn->sk->daddr : IPA_NONE; d->local_ip = conn->sk ? conn->sk->saddr : IPA_NONE; d->as4 = p_ok ? p->as4_session : 0; } static uint bgp_find_update_afi(byte *pos, uint len); static int bgp_estimate_add_path(struct bgp_proto *p, byte *pkt, uint len) { /* No need to estimate it for other messages than UPDATE */ if (pkt[18] != PKT_UPDATE) return 0; /* 1 -> no channel, 2 -> all channels, 3 -> some channels */ if (p->summary_add_path_rx < 3) return p->summary_add_path_rx == 2; uint afi = bgp_find_update_afi(pkt, len); struct bgp_channel *c = bgp_get_channel(p, afi); if (!c) { /* Either frame error (if !afi) or unknown AFI/SAFI, will be reported later in regular parsing */ BGP_TRACE(D_PACKETS, "MRT processing noticed invalid packet"); return 0; } return c->add_path_rx; } static void bgp_dump_message(struct bgp_conn *conn, byte *pkt, uint len) { struct mrt_bgp_data d; init_mrt_bgp_data(conn, &d); d.message = pkt; d.msg_len = len; d.add_path = bgp_estimate_add_path(conn->bgp, pkt, len); mrt_dump_bgp_message(&d); } void bgp_dump_state_change(struct bgp_conn *conn, uint old, uint new) { struct mrt_bgp_data d; init_mrt_bgp_data(conn, &d); d.old_state = old; d.new_state = new; mrt_dump_bgp_state_change(&d); } static byte * bgp_create_notification(struct bgp_conn *conn, byte *buf) { struct bgp_proto *p = conn->bgp; BGP_TRACE(D_PACKETS, "Sending NOTIFICATION(code=%d.%d)", conn->notify_code, conn->notify_subcode); buf[0] = conn->notify_code; buf[1] = conn->notify_subcode; memcpy(buf+2, conn->notify_data, conn->notify_size); return buf + 2 + conn->notify_size; } /* Capability negotiation as per RFC 5492 */ const struct bgp_af_caps * bgp_find_af_caps(struct bgp_caps *caps, u32 afi) { struct bgp_af_caps *ac; WALK_AF_CAPS(caps, ac) if (ac->afi == afi) return ac; return NULL; } static struct bgp_af_caps * bgp_get_af_caps(struct bgp_caps **pcaps, u32 afi) { struct bgp_caps *caps = *pcaps; struct bgp_af_caps *ac; WALK_AF_CAPS(caps, ac) if (ac->afi == afi) return ac; uint n = caps->af_count; if (uint_is_pow2(n)) *pcaps = caps = mb_realloc(caps, sizeof(struct bgp_caps) + (2 * n) * sizeof(struct bgp_af_caps)); ac = &caps->af_data[caps->af_count++]; memset(ac, 0, sizeof(struct bgp_af_caps)); ac->afi = afi; return ac; } static int bgp_af_caps_cmp(const void *X, const void *Y) { const struct bgp_af_caps *x = X, *y = Y; return (x->afi < y->afi) ? -1 : (x->afi > y->afi) ? 1 : 0; } void bgp_prepare_capabilities(struct bgp_conn *conn) { struct bgp_proto *p = conn->bgp; struct bgp_channel *c; struct bgp_caps *caps; struct bgp_af_caps *ac; if (!p->cf->capabilities) { /* Just prepare empty local_caps */ conn->local_caps = mb_allocz(p->p.pool, sizeof(struct bgp_caps)); return; } /* Prepare bgp_caps structure */ int n = list_length(&p->p.channels); caps = mb_allocz(p->p.pool, sizeof(struct bgp_caps) + n * sizeof(struct bgp_af_caps)); conn->local_caps = caps; caps->as4_support = p->cf->enable_as4; 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; if (p->cf->gr_mode) { caps->gr_aware = 1; caps->gr_time = p->cf->gr_time; caps->gr_flags = p->p.gr_recovery ? BGP_GRF_RESTART : 0; } if (p->cf->llgr_mode) caps->llgr_aware = 1; if (p->cf->enable_hostname && config->hostname) { size_t length = strlen(config->hostname); char *hostname = mb_allocz(p->p.pool, length+1); memcpy(hostname, config->hostname, length+1); caps->hostname = hostname; } /* Allocate and fill per-AF fields */ BGP_WALK_CHANNELS(p, c) { ac = &caps->af_data[caps->af_count++]; ac->afi = c->afi; ac->ready = 1; ac->ext_next_hop = bgp_channel_is_ipv4(c) && c->cf->ext_next_hop; caps->any_ext_next_hop |= ac->ext_next_hop; ac->add_path = c->cf->add_path; caps->any_add_path |= ac->add_path; if (c->cf->gr_able) { ac->gr_able = 1; if (p->p.gr_recovery) ac->gr_af_flags |= BGP_GRF_FORWARDING; } if (c->cf->llgr_able) { ac->llgr_able = 1; ac->llgr_time = c->cf->llgr_time; if (p->p.gr_recovery) ac->llgr_flags |= BGP_LLGRF_FORWARDING; } } /* Sort capability fields by AFI/SAFI */ qsort(caps->af_data, caps->af_count, sizeof(struct bgp_af_caps), bgp_af_caps_cmp); } static byte * bgp_write_capabilities(struct bgp_conn *conn, byte *buf) { struct bgp_proto *p = conn->bgp; struct bgp_caps *caps = conn->local_caps; struct bgp_af_caps *ac; byte *buf_head = buf; byte *data; /* Create capability list in buffer */ /* * Note that max length is ~ 22+21*af_count. With max 12 channels that is * 274. We are limited just by buffer size (4096, minus header), as we support * extended optional parameres. Therefore, we have enough space for expansion. */ WALK_AF_CAPS(caps, ac) if (ac->ready) { *buf++ = 1; /* Capability 1: Multiprotocol extensions */ *buf++ = 4; /* Capability data length */ put_af4(buf, ac->afi); buf += 4; } if (caps->route_refresh) { *buf++ = 2; /* Capability 2: Support for route refresh */ *buf++ = 0; /* Capability data length */ } if (caps->any_ext_next_hop) { *buf++ = 5; /* Capability 5: Support for extended next hop */ *buf++ = 0; /* Capability data length, will be fixed later */ data = buf; WALK_AF_CAPS(caps, ac) if (ac->ext_next_hop) { put_af4(buf, ac->afi); put_u16(buf+4, BGP_AFI_IPV6); buf += 6; } data[-1] = buf - data; } if (caps->ext_messages) { *buf++ = 6; /* Capability 6: Support for extended messages */ *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 */ *buf++ = 0; /* Capability data length, will be fixed later */ data = buf; put_u16(buf, caps->gr_time); buf[0] |= caps->gr_flags; buf += 2; WALK_AF_CAPS(caps, ac) if (ac->gr_able) { put_af3(buf, ac->afi); buf[3] = ac->gr_af_flags; buf += 4; } data[-1] = buf - data; } if (caps->as4_support) { *buf++ = 65; /* Capability 65: Support for 4-octet AS number */ *buf++ = 4; /* Capability data length */ put_u32(buf, p->public_as); buf += 4; } if (caps->any_add_path) { *buf++ = 69; /* Capability 69: Support for ADD-PATH */ *buf++ = 0; /* Capability data length, will be fixed later */ data = buf; WALK_AF_CAPS(caps, ac) if (ac->add_path) { put_af3(buf, ac->afi); buf[3] = ac->add_path; buf += 4; } data[-1] = buf - data; } if (caps->enhanced_refresh) { *buf++ = 70; /* Capability 70: Support for enhanced route refresh */ *buf++ = 0; /* Capability data length */ } if (caps->llgr_aware) { *buf++ = 71; /* Capability 71: Support for long-lived graceful restart */ *buf++ = 0; /* Capability data length, will be fixed later */ data = buf; WALK_AF_CAPS(caps, ac) if (ac->llgr_able) { put_af3(buf, ac->afi); buf[3] = ac->llgr_flags; put_u24(buf+4, ac->llgr_time); buf += 7; } data[-1] = buf - data; } if (caps->hostname) { *buf++ = 73; /* Capability 73: Hostname */ *buf++ = 0; /* Capability data length */ data = buf; /* Hostname */ size_t length = strlen(caps->hostname); *buf++ = length; memcpy(buf, caps->hostname, length); buf += length; /* Domain, not implemented */ *buf++ = 0; data[-1] = buf - data; } caps->length = buf - buf_head; return buf; } static int 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; conn->remote_caps = NULL; } caps->length += len; while (len > 0) { if (len < 2 || len < (2 + pos[1])) goto err; /* Capability length */ cl = pos[1]; /* Capability type */ switch (pos[0]) { case 1: /* Multiprotocol capability, RFC 4760 */ if (cl != 4) goto err; af = get_af4(pos+2); ac = bgp_get_af_caps(&caps, af); ac->ready = 1; break; case 2: /* Route refresh capability, RFC 2918 */ if (cl != 0) goto err; caps->route_refresh = 1; break; case 5: /* Extended next hop encoding capability, RFC 5549 */ if (cl % 6) goto err; for (i = 0; i < cl; i += 6) { /* Specified only for IPv4 prefixes with IPv6 next hops */ if ((get_u16(pos+2+i+0) != BGP_AFI_IPV4) || (get_u16(pos+2+i+4) != BGP_AFI_IPV6)) continue; af = get_af4(pos+2+i); ac = bgp_get_af_caps(&caps, af); ac->ext_next_hop = 1; } break; case 6: /* Extended message length capability, RFC draft */ if (cl != 0) goto err; 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; /* Only the last instance is valid */ WALK_AF_CAPS(caps, ac) { ac->gr_able = 0; ac->gr_af_flags = 0; } caps->gr_aware = 1; caps->gr_flags = pos[2] & 0xf0; caps->gr_time = get_u16(pos + 2) & 0x0fff; for (i = 2; i < cl; i += 4) { af = get_af3(pos+2+i); ac = bgp_get_af_caps(&caps, af); ac->gr_able = 1; ac->gr_af_flags = pos[2+i+3]; } break; case 65: /* AS4 capability, RFC 6793 */ if (cl != 4) goto err; caps->as4_support = 1; caps->as4_number = get_u32(pos + 2); break; case 69: /* ADD-PATH capability, RFC 7911 */ if (cl % 4) goto err; for (i = 0; i < cl; i += 4) { byte val = pos[2+i+3]; if (!val || (val > BGP_ADD_PATH_FULL)) { log(L_WARN "%s: Got ADD-PATH capability with unknown value %u, ignoring", p->p.name, val); break; } } for (i = 0; i < cl; i += 4) { af = get_af3(pos+2+i); ac = bgp_get_af_caps(&caps, af); ac->add_path = pos[2+i+3]; } break; case 70: /* Enhanced route refresh capability, RFC 7313 */ if (cl != 0) goto err; caps->enhanced_refresh = 1; break; case 71: /* Long lived graceful restart capability, RFC draft */ if (cl % 7) goto err; /* Presumably, only the last instance is valid */ WALK_AF_CAPS(caps, ac) { ac->llgr_able = 0; ac->llgr_flags = 0; ac->llgr_time = 0; } caps->llgr_aware = 1; for (i = 0; i < cl; i += 7) { af = get_af3(pos+2+i); ac = bgp_get_af_caps(&caps, af); ac->llgr_able = 1; ac->llgr_flags = pos[2+i+3]; ac->llgr_time = get_u24(pos + 2+i+4); } break; case 73: /* Hostname, RFC draft */ if ((cl < 2) || (cl < 2 + pos[2])) goto err; int length = pos[2]; char *hostname = mb_allocz(p->p.pool, length+1); memcpy(hostname, pos + 3, length); hostname[length] = 0; for (i = 0; i < length; i++) if (hostname[i] < ' ') hostname[i] = ' '; caps->hostname = hostname; /* We can safely ignore all other capabilities */ } ADVANCE(pos, len, 2 + cl); } /* The LLGR capability must be advertised together with the GR capability, otherwise it must be disregarded */ if (!caps->gr_aware && caps->llgr_aware) { caps->llgr_aware = 0; WALK_AF_CAPS(caps, ac) { ac->llgr_able = 0; ac->llgr_flags = 0; ac->llgr_time = 0; } } conn->remote_caps = caps; return 0; err: mb_free(caps); bgp_error(conn, 2, err_subcode, NULL, 0); return -1; } static int bgp_check_capabilities(struct bgp_conn *conn) { struct bgp_proto *p = conn->bgp; struct bgp_caps *local = conn->local_caps; struct bgp_caps *remote = conn->remote_caps; struct bgp_channel *c; int count = 0; /* This is partially overlapping with bgp_conn_enter_established_state(), but we need to run this just after we receive OPEN message */ BGP_WALK_CHANNELS(p, c) { const struct bgp_af_caps *loc = bgp_find_af_caps(local, c->afi); const struct bgp_af_caps *rem = bgp_find_af_caps(remote, c->afi); /* Find out whether this channel will be active */ int active = loc && loc->ready && ((rem && rem->ready) || (!remote->length && (c->afi == BGP_AF_IPV4))); /* Mandatory must be active */ if (c->cf->mandatory && !active) return 0; if (active) count++; } /* We need at least one channel active */ if (!count) return 0; return 1; } static int bgp_read_options(struct bgp_conn *conn, byte *pos, uint len, uint rest) { struct bgp_proto *p = conn->bgp; int ext = 0; /* Handle extended length (draft-ietf-idr-ext-opt-param-07) */ if ((len > 0) && (rest > 0) && (pos[0] == 255)) { if (rest < 3) goto err; /* Update pos/len to describe optional data */ len = get_u16(pos+1); ext = 1; pos += 3; rest -= 3; } /* Verify that optional data fits into OPEN packet */ if (len > rest) goto err; /* Length of option parameter header */ uint hlen = ext ? 3 : 2; while (len > 0) { if (len < hlen) goto err; uint otype = get_u8(pos); uint olen = ext ? get_u16(pos+1) : get_u8(pos+1); if (len < (hlen + olen)) goto err; if (otype == 2) { /* BGP capabilities, RFC 5492 */ if (p->cf->capabilities) if (bgp_read_capabilities(conn, pos + hlen, olen) < 0) return -1; } else { /* Unknown option */ bgp_error(conn, 2, 4, pos, hlen + olen); return -1; } ADVANCE(pos, len, hlen + olen); } /* Prepare empty caps if no capability option was announced */ if (!conn->remote_caps) conn->remote_caps = mb_allocz(p->p.pool, sizeof(struct bgp_caps)); return 0; err: bgp_error(conn, 2, 0, NULL, 0); return -1; } static byte * bgp_create_open(struct bgp_conn *conn, byte *buf) { struct bgp_proto *p = conn->bgp; BGP_TRACE(D_PACKETS, "Sending OPEN(ver=%d,as=%d,hold=%d,id=%08x)", BGP_VERSION, p->public_as, p->cf->hold_time, p->local_id); buf[0] = BGP_VERSION; put_u16(buf+1, (p->public_as < 0xFFFF) ? p->public_as : AS_TRANS); put_u16(buf+3, p->cf->hold_time); put_u32(buf+5, p->local_id); if (p->cf->capabilities) { /* Prepare local_caps and write capabilities to buffer */ byte *pos = buf+12; byte *end = bgp_write_capabilities(conn, pos); uint len = end - pos; if (len < 254) { buf[9] = len + 2; /* Optional parameters length */ buf[10] = 2; /* Option 2: Capability list */ buf[11] = len; /* Option data length */ } else /* draft-ietf-idr-ext-opt-param-07 */ { /* Move capabilities 4 B forward */ memmove(buf + 16, pos, len); pos = buf + 16; end = pos + len; buf[9] = 255; /* Non-ext OP length, fake */ buf[10] = 255; /* Non-ext OP type, signals extended length */ put_u16(buf+11, len + 3); /* Extended optional parameters length */ buf[13] = 2; /* Option 2: Capability list */ put_u16(buf+14, len); /* Option extended data length */ } return end; } else { buf[9] = 0; /* No optional parameters */ return buf + 10; } return buf; } static void bgp_rx_open(struct bgp_conn *conn, byte *pkt, uint len) { struct bgp_proto *p = conn->bgp; struct bgp_conn *other; u32 asn, hold, id; /* Check state */ if (conn->state != BS_OPENSENT) { bgp_error(conn, 5, fsm_err_subcode[conn->state], NULL, 0); return; } /* Check message length */ if (len < 29) { bgp_error(conn, 1, 2, pkt+16, 2); return; } if (pkt[19] != BGP_VERSION) { u16 val = BGP_VERSION; bgp_error(conn, 2, 1, (byte *) &val, 2); return; } asn = get_u16(pkt+20); hold = get_u16(pkt+22); id = get_u32(pkt+24); BGP_TRACE(D_PACKETS, "Got OPEN(as=%d,hold=%d,id=%R)", asn, hold, id); if (bgp_read_options(conn, pkt+29, pkt[28], len-29) < 0) return; /* RFC 4271 4.2 - hold time must be either 0 or at least 3 */ if (hold > 0 && hold < 3) { bgp_error(conn, 2, 6, pkt+22, 2); return; } /* Compute effective hold and keepalive times */ uint hold_time = MIN(hold, p->cf->hold_time); uint keepalive_time = p->cf->keepalive_time ? (p->cf->keepalive_time * hold_time / p->cf->hold_time) : hold_time / 3; /* Keepalive time might be rounded down to zero */ if (hold_time && !keepalive_time) keepalive_time = 1; /* Check effective values against configured minimums */ if ((hold_time < p->cf->min_hold_time) || (keepalive_time < p->cf->min_keepalive_time)) { bgp_error(conn, 2, 6, pkt+22, 2); return; } /* RFC 6286 2.2 - router ID is nonzero and AS-wide unique */ if (!id || (p->is_internal && id == p->local_id)) { bgp_error(conn, 2, 3, pkt+24, -4); return; } /* RFC 5492 4 - check for required capabilities */ if (p->cf->capabilities && !bgp_check_capabilities(conn)) { bgp_error(conn, 2, 7, NULL, 0); return; } struct bgp_caps *caps = conn->remote_caps; if (caps->as4_support) { u32 as4 = caps->as4_number; if ((as4 != asn) && (asn != AS_TRANS)) log(L_WARN "%s: Peer advertised inconsistent AS numbers", p->p.name); /* When remote ASN is unspecified, it must be external one */ if (p->remote_as ? (as4 != p->remote_as) : (as4 == p->local_as)) { as4 = htonl(as4); bgp_error(conn, 2, 2, (byte *) &as4, 4); return; } conn->received_as = as4; } else { if (p->remote_as ? (asn != p->remote_as) : (asn == p->local_as)) { bgp_error(conn, 2, 2, pkt+20, 2); return; } 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) { case BS_CONNECT: case BS_ACTIVE: /* Stop outgoing connection attempts */ bgp_conn_enter_idle_state(other); break; case BS_IDLE: case BS_OPENSENT: case BS_CLOSE: break; case BS_OPENCONFIRM: /* * Description of collision detection rules in RFC 4271 is confusing and * contradictory, but it is essentially: * * 1. Router with higher ID is dominant * 2. If both have the same ID, router with higher ASN is dominant [RFC6286] * 3. When both connections are in OpenConfirm state, one initiated by * the dominant router is kept. * * The first line in the expression below evaluates whether the neighbor * is dominant, the second line whether the new connection was initiated * by the neighbor. If both are true (or both are false), we keep the new * connection, otherwise we keep the old one. */ if (((p->local_id < id) || ((p->local_id == id) && (p->public_as < p->remote_as))) == (conn == &p->incoming_conn)) { /* Should close the other connection */ BGP_TRACE(D_EVENTS, "Connection collision, giving up the other connection"); bgp_error(other, 6, 7, NULL, 0); break; } /* Fall thru */ case BS_ESTABLISHED: /* Should close this connection */ BGP_TRACE(D_EVENTS, "Connection collision, giving up this connection"); bgp_error(conn, 6, 7, NULL, 0); return; default: bug("bgp_rx_open: Unknown state"); } /* Update our local variables */ conn->hold_time = hold_time; conn->keepalive_time = keepalive_time; conn->as4_session = conn->local_caps->as4_support && caps->as4_support; conn->ext_messages = conn->local_caps->ext_messages && caps->ext_messages; p->remote_id = id; DBG("BGP: Hold timer set to %d, keepalive to %d, AS to %d, ID to %x, AS4 session to %d\n", conn->hold_time, conn->keepalive_time, p->remote_as, p->remote_id, conn->as4_session); bgp_schedule_packet(conn, NULL, PKT_KEEPALIVE); bgp_start_timer(conn->hold_timer, conn->hold_time); bgp_conn_enter_openconfirm_state(conn); } /* * Next hop handling */ #define REPORT(msg, args...) \ ({ log(L_REMOTE "%s: " msg, s->proto->p.name, ## args); }) #define DISCARD(msg, args...) \ ({ REPORT(msg, ## args); return; }) #define WITHDRAW(msg, args...) \ ({ REPORT(msg, ## args); s->err_withdraw = 1; return; }) #define REJECT(msg, args...) \ ({ log(L_ERR "%s: " msg, s->proto->p.name, ## args); s->err_reject = 1; return; }) #define BAD_AFI "Unexpected AF <%u/%u> in UPDATE" #define BAD_NEXT_HOP "Invalid NEXT_HOP attribute" #define NO_NEXT_HOP "Missing NEXT_HOP attribute" #define NO_LABEL_STACK "Missing MPLS stack" #define MISMATCHED_AF " - mismatched address family (%I for %s)" static void bgp_apply_next_hop(struct bgp_parse_state *s, rta *a, ip_addr gw, ip_addr ll) { struct bgp_proto *p = s->proto; struct bgp_channel *c = s->channel; if (c->cf->gw_mode == GW_DIRECT) { neighbor *nbr = NULL; /* GW_DIRECT -> single_hop -> p->neigh != NULL */ if (ipa_nonzero2(gw)) nbr = neigh_find(&p->p, gw, NULL, 0); else if (ipa_nonzero(ll)) nbr = neigh_find(&p->p, ll, p->neigh->iface, 0); else WITHDRAW(BAD_NEXT_HOP " - zero address"); if (!nbr) WITHDRAW(BAD_NEXT_HOP " - address %I not directly reachable", ipa_nonzero(gw) ? gw : ll); if (nbr->scope == SCOPE_HOST) WITHDRAW(BAD_NEXT_HOP " - address %I is local", nbr->addr); a->dest = RTD_UNICAST; a->nh.gw = nbr->addr; a->nh.iface = nbr->iface; a->igp_metric = c->cf->cost; } else /* GW_RECURSIVE */ { if (ipa_zero2(gw)) WITHDRAW(BAD_NEXT_HOP " - zero address"); rtable *tab = ipa_is_ip4(gw) ? c->igp_table_ip4 : c->igp_table_ip6; ip_addr lla = (c->cf->next_hop_prefer == NHP_LOCAL) ? ll : IPA_NONE; s->hostentry = rt_get_hostentry(tab, gw, lla, c->c.table); if (!s->mpls) rta_apply_hostentry(a, s->hostentry, NULL); /* With MPLS, hostentry is applied later in bgp_apply_mpls_labels() */ } } static void bgp_apply_mpls_labels(struct bgp_parse_state *s, rta *a, u32 *labels, uint lnum) { if (lnum > MPLS_MAX_LABEL_STACK) { REPORT("Too many MPLS labels ($u)", lnum); a->dest = RTD_UNREACHABLE; a->hostentry = NULL; a->nh = (struct nexthop) { }; return; } /* Handle implicit NULL as empty MPLS stack */ if ((lnum == 1) && (labels[0] == BGP_MPLS_NULL)) lnum = 0; if (s->channel->cf->gw_mode == GW_DIRECT) { a->nh.labels = lnum; memcpy(a->nh.label, labels, 4*lnum); } else /* GW_RECURSIVE */ { mpls_label_stack ms; ms.len = lnum; memcpy(ms.stack, labels, 4*lnum); rta_apply_hostentry(a, s->hostentry, &ms); } } static void bgp_apply_flow_validation(struct bgp_parse_state *s, const net_addr *n, rta *a) { struct bgp_channel *c = s->channel; int valid = rt_flowspec_check(c->base_table, c->c.table, n, a, s->proto->is_interior); a->dest = valid ? RTD_NONE : RTD_UNREACHABLE; /* Invalidate cached rta if dest changes */ if (s->cached_rta && (s->cached_rta->dest != a->dest)) { rta_free(s->cached_rta); s->cached_rta = NULL; } } static int bgp_match_src(struct bgp_export_state *s, int mode) { switch (mode) { case NH_NO: return 0; case NH_ALL: return 1; case NH_IBGP: return s->src && s->src->is_internal; case NH_EBGP: return s->src && !s->src->is_internal; default: return 0; } } static inline int bgp_use_next_hop(struct bgp_export_state *s, eattr *a) { struct bgp_proto *p = s->proto; struct bgp_channel *c = s->channel; ip_addr *nh = (void *) a->u.ptr->data; /* Handle next hop self option */ if (c->cf->next_hop_self && bgp_match_src(s, c->cf->next_hop_self)) return 0; /* Handle next hop keep option */ if (c->cf->next_hop_keep && bgp_match_src(s, c->cf->next_hop_keep)) return 1; /* Keep it when explicitly set in export filter */ if (a->fresh) return 1; /* Check for non-matching AF */ if ((ipa_is_ip4(*nh) != bgp_channel_is_ipv4(c)) && !c->ext_next_hop) return 0; /* Do not pass NEXT_HOP between different VRFs */ if (p->p.vrf_set && s->src && s->src->p.vrf_set && (p->p.vrf != s->src->p.vrf)) return 0; /* Keep it when exported to internal peers */ if (p->is_interior && ipa_nonzero(*nh)) return 1; /* Keep it when forwarded between single-hop BGPs on the same iface */ struct iface *ifa = (s->src && s->src->neigh && (s->src->p.proto_state != PS_DOWN)) ? s->src->neigh->iface : NULL; return p->neigh && (p->neigh->iface == ifa); } static inline int bgp_use_gateway(struct bgp_export_state *s) { struct bgp_proto *p = s->proto; struct bgp_channel *c = s->channel; rta *ra = s->route->attrs; /* Handle next hop self option - also applies to gateway */ if (c->cf->next_hop_self && bgp_match_src(s, c->cf->next_hop_self)) return 0; /* We need one valid global gateway */ if ((ra->dest != RTD_UNICAST) || ra->nh.next || ipa_zero(ra->nh.gw) || ipa_is_link_local(ra->nh.gw)) return 0; /* Check for non-matching AF */ if ((ipa_is_ip4(ra->nh.gw) != bgp_channel_is_ipv4(c)) && !c->ext_next_hop) return 0; /* Do not use gateway from different VRF */ if (p->p.vrf_set && ra->nh.iface && (p->p.vrf != ra->nh.iface->master)) return 0; /* Use it when exported to internal peers */ if (p->is_interior) return 1; /* Use it when forwarded to single-hop BGP peer on on the same iface */ return p->neigh && (p->neigh->iface == ra->nh.iface); } static void bgp_update_next_hop_ip(struct bgp_export_state *s, eattr *a, ea_list **to) { if (!a || !bgp_use_next_hop(s, a)) { if (bgp_use_gateway(s)) { rta *ra = s->route->attrs; ip_addr nh[1] = { ra->nh.gw }; bgp_set_attr_data(to, s->pool, BA_NEXT_HOP, 0, nh, 16); if (s->mpls) { u32 implicit_null = BGP_MPLS_NULL; u32 *labels = ra->nh.labels ? ra->nh.label : &implicit_null; uint lnum = ra->nh.labels ? ra->nh.labels : 1; bgp_set_attr_data(to, s->pool, BA_MPLS_LABEL_STACK, 0, labels, lnum * 4); } else bgp_unset_attr(to, s->pool, BA_MPLS_LABEL_STACK); } else { ip_addr nh[2] = { s->channel->next_hop_addr, s->channel->link_addr }; bgp_set_attr_data(to, s->pool, BA_NEXT_HOP, 0, nh, ipa_nonzero(nh[1]) ? 32 : 16); s->local_next_hop = 1; /* TODO: Use local MPLS assigned label */ if (s->mpls) { u32 implicit_null = BGP_MPLS_NULL; bgp_set_attr_data(to, s->pool, BA_MPLS_LABEL_STACK, 0, &implicit_null, 4); } else bgp_unset_attr(to, s->pool, BA_MPLS_LABEL_STACK); } } /* Check if next hop is valid */ a = bgp_find_attr(*to, BA_NEXT_HOP); if (!a) REJECT(NO_NEXT_HOP); ip_addr *nh = (void *) a->u.ptr->data; ip_addr peer = s->proto->remote_ip; uint len = a->u.ptr->length; /* Forbid zero next hop */ if (ipa_zero2(nh[0]) && ((len != 32) || ipa_zero(nh[1]))) REJECT(BAD_NEXT_HOP " - zero address"); /* Forbid next hop equal to neighbor IP */ if (ipa_equal(peer, nh[0]) || ((len == 32) && ipa_equal(peer, nh[1]))) REJECT(BAD_NEXT_HOP " - neighbor address %I", peer); /* Forbid next hop with non-matching AF */ if ((ipa_is_ip4(nh[0]) != bgp_channel_is_ipv4(s->channel)) && !s->channel->ext_next_hop) REJECT(BAD_NEXT_HOP MISMATCHED_AF, nh[0], s->channel->desc->name); /* Just check if MPLS stack */ if (s->mpls && !bgp_find_attr(*to, BA_MPLS_LABEL_STACK)) REJECT(NO_LABEL_STACK); } static uint bgp_encode_next_hop_ip(struct bgp_write_state *s, eattr *a, byte *buf, uint size UNUSED) { /* This function is used only for MP-BGP, see bgp_encode_next_hop() for IPv4 BGP */ ip_addr *nh = (void *) a->u.ptr->data; uint len = a->u.ptr->length; ASSERT((len == 16) || (len == 32)); /* * Both IPv4 and IPv6 next hops can be used (with ext_next_hop enabled). This * is specified in RFC 5549 for IPv4 and in RFC 4798 for IPv6. The difference * is that IPv4 address is directly encoded with IPv4 NLRI, but as IPv4-mapped * IPv6 address with IPv6 NLRI. */ if (bgp_channel_is_ipv4(s->channel) && ipa_is_ip4(nh[0])) { put_ip4(buf, ipa_to_ip4(nh[0])); return 4; } put_ip6(buf, ipa_to_ip6(nh[0])); if (len == 32) put_ip6(buf+16, ipa_to_ip6(nh[1])); return len; } static void bgp_decode_next_hop_ip(struct bgp_parse_state *s, byte *data, uint len, rta *a) { struct bgp_channel *c = s->channel; struct adata *ad = lp_alloc_adata(s->pool, 32); ip_addr *nh = (void *) ad->data; if (len == 4) { nh[0] = ipa_from_ip4(get_ip4(data)); nh[1] = IPA_NONE; } else if (len == 16) { nh[0] = ipa_from_ip6(get_ip6(data)); nh[1] = IPA_NONE; if (ipa_is_link_local(nh[0])) { nh[1] = nh[0]; nh[0] = IPA_NONE; } } else if (len == 32) { nh[0] = ipa_from_ip6(get_ip6(data)); nh[1] = ipa_from_ip6(get_ip6(data+16)); if (ipa_is_link_local(nh[0])) { nh[1] = nh[0]; nh[0] = IPA_NONE; } if (ipa_is_ip4(nh[0]) || !ipa_is_link_local(nh[1])) nh[1] = IPA_NONE; } else bgp_parse_error(s, 9); if (ipa_zero(nh[1])) ad->length = 16; if ((bgp_channel_is_ipv4(c) != ipa_is_ip4(nh[0])) && !c->ext_next_hop) WITHDRAW(BAD_NEXT_HOP MISMATCHED_AF, nh[0], c->desc->name); // XXXX validate next hop bgp_set_attr_ptr(&(a->eattrs), s->pool, BA_NEXT_HOP, 0, ad); bgp_apply_next_hop(s, a, nh[0], nh[1]); } static uint bgp_encode_next_hop_vpn(struct bgp_write_state *s, eattr *a, byte *buf, uint size UNUSED) { ip_addr *nh = (void *) a->u.ptr->data; uint len = a->u.ptr->length; ASSERT((len == 16) || (len == 32)); /* * Both IPv4 and IPv6 next hops can be used (with ext_next_hop enabled). This * is specified in RFC 5549 for VPNv4 and in RFC 4659 for VPNv6. The difference * is that IPv4 address is directly encoded with VPNv4 NLRI, but as IPv4-mapped * IPv6 address with VPNv6 NLRI. */ if (bgp_channel_is_ipv4(s->channel) && ipa_is_ip4(nh[0])) { put_u64(buf, 0); /* VPN RD is 0 */ put_ip4(buf+8, ipa_to_ip4(nh[0])); return 12; } put_u64(buf, 0); /* VPN RD is 0 */ put_ip6(buf+8, ipa_to_ip6(nh[0])); if (len == 16) return 24; put_u64(buf+24, 0); /* VPN RD is 0 */ put_ip6(buf+32, ipa_to_ip6(nh[1])); return 48; } static void bgp_decode_next_hop_vpn(struct bgp_parse_state *s, byte *data, uint len, rta *a) { struct bgp_channel *c = s->channel; struct adata *ad = lp_alloc_adata(s->pool, 32); ip_addr *nh = (void *) ad->data; if (len == 12) { nh[0] = ipa_from_ip4(get_ip4(data+8)); nh[1] = IPA_NONE; } else if (len == 24) { nh[0] = ipa_from_ip6(get_ip6(data+8)); nh[1] = IPA_NONE; if (ipa_is_link_local(nh[0])) { nh[1] = nh[0]; nh[0] = IPA_NONE; } } else if (len == 48) { nh[0] = ipa_from_ip6(get_ip6(data+8)); nh[1] = ipa_from_ip6(get_ip6(data+32)); if (ipa_is_ip4(nh[0]) || !ip6_is_link_local(nh[1])) nh[1] = IPA_NONE; } else bgp_parse_error(s, 9); if (ipa_zero(nh[1])) ad->length = 16; /* XXXX which error */ if ((get_u64(data) != 0) || ((len == 48) && (get_u64(data+24) != 0))) bgp_parse_error(s, 9); if ((bgp_channel_is_ipv4(c) != ipa_is_ip4(nh[0])) && !c->ext_next_hop) WITHDRAW(BAD_NEXT_HOP MISMATCHED_AF, nh[0], c->desc->name); // XXXX validate next hop bgp_set_attr_ptr(&(a->eattrs), s->pool, BA_NEXT_HOP, 0, ad); bgp_apply_next_hop(s, a, nh[0], nh[1]); } static uint bgp_encode_next_hop_none(struct bgp_write_state *s UNUSED, eattr *a UNUSED, byte *buf UNUSED, uint size UNUSED) { return 0; } static void bgp_decode_next_hop_none(struct bgp_parse_state *s UNUSED, byte *data UNUSED, uint len UNUSED, rta *a UNUSED) { /* * Although we expect no next hop and RFC 7606 7.11 states that attribute * MP_REACH_NLRI with unexpected next hop length is considered malformed, * FlowSpec RFC 5575 4 states that next hop shall be ignored on receipt. */ return; } static void bgp_update_next_hop_none(struct bgp_export_state *s, eattr *a, ea_list **to) { /* NEXT_HOP shall not pass */ if (a) bgp_unset_attr(to, s->pool, BA_NEXT_HOP); } /* * UPDATE */ static void bgp_rte_update(struct bgp_parse_state *s, const net_addr *n, u32 path_id, rta *a0) { if (path_id != s->last_id) { s->last_src = rt_get_source(&s->proto->p, path_id); s->last_id = path_id; rta_free(s->cached_rta); s->cached_rta = NULL; } if (!a0) { /* Route update was changed to withdraw */ if (s->err_withdraw && s->reach_nlri_step) REPORT("Invalid route %N withdrawn", n); /* Route withdraw */ rte_update3(&s->channel->c, n, NULL, s->last_src); return; } /* Prepare cached route attributes */ if (s->cached_rta == NULL) { /* Workaround for rta_lookup() breaking eattrs */ ea_list *ea = a0->eattrs; s->cached_rta = rta_lookup(a0); a0->eattrs = ea; } rta *a = rta_clone(s->cached_rta); rte *e = rte_get_temp(a, s->last_src); e->pflags = 0; rte_update3(&s->channel->c, n, e, s->last_src); } static void bgp_encode_mpls_labels(struct bgp_write_state *s UNUSED, const adata *mpls, byte **pos, uint *size, byte *pxlen) { const u32 dummy = 0; const u32 *labels = mpls ? (const u32 *) mpls->data : &dummy; uint lnum = mpls ? (mpls->length / 4) : 1; for (uint i = 0; i < lnum; i++) { put_u24(*pos, labels[i] << 4); ADVANCE(*pos, *size, 3); } /* Add bottom-of-stack flag */ (*pos)[-1] |= BGP_MPLS_BOS; *pxlen += 24 * lnum; } static void bgp_decode_mpls_labels(struct bgp_parse_state *s, byte **pos, uint *len, uint *pxlen, rta *a) { u32 labels[BGP_MPLS_MAX], label; uint lnum = 0; do { if (*pxlen < 24) bgp_parse_error(s, 1); label = get_u24(*pos); labels[lnum++] = label >> 4; ADVANCE(*pos, *len, 3); *pxlen -= 24; /* RFC 8277 2.4 - withdraw does not have variable-size MPLS stack but fixed-size 24-bit Compatibility field, which MUST be ignored */ if (!s->reach_nlri_step) return; } while (!(label & BGP_MPLS_BOS)); if (!a) return; /* Attach MPLS attribute unless we already have one */ if (!s->mpls_labels) { s->mpls_labels = lp_alloc_adata(s->pool, 4*BGP_MPLS_MAX); bgp_set_attr_ptr(&(a->eattrs), s->pool, BA_MPLS_LABEL_STACK, 0, s->mpls_labels); } /* Overwrite data in the attribute */ s->mpls_labels->length = 4*lnum; memcpy(s->mpls_labels->data, labels, 4*lnum); /* Update next hop entry in rta */ bgp_apply_mpls_labels(s, a, labels, lnum); /* Attributes were changed, invalidate cached entry */ rta_free(s->cached_rta); s->cached_rta = NULL; return; } static uint bgp_encode_nlri_ip4(struct bgp_write_state *s, struct bgp_bucket *buck, byte *buf, uint size) { byte *pos = buf; while (!EMPTY_LIST(buck->prefixes) && (size >= BGP_NLRI_MAX)) { struct bgp_prefix *px = HEAD(buck->prefixes); struct net_addr_ip4 *net = (void *) px->net; /* Encode path ID */ if (s->add_path) { put_u32(pos, px->path_id); ADVANCE(pos, size, 4); } /* Encode prefix length */ *pos = net->pxlen; ADVANCE(pos, size, 1); /* Encode MPLS labels */ if (s->mpls) bgp_encode_mpls_labels(s, s->mpls_labels, &pos, &size, pos - 1); /* Encode prefix body */ ip4_addr a = ip4_hton(net->prefix); uint b = (net->pxlen + 7) / 8; memcpy(pos, &a, b); ADVANCE(pos, size, b); bgp_free_prefix(s->channel, px); } return pos - buf; } static void bgp_decode_nlri_ip4(struct bgp_parse_state *s, byte *pos, uint len, rta *a) { while (len) { net_addr_ip4 net; u32 path_id = 0; /* Decode path ID */ if (s->add_path) { if (len < 5) bgp_parse_error(s, 1); path_id = get_u32(pos); ADVANCE(pos, len, 4); } /* Decode prefix length */ uint l = *pos; ADVANCE(pos, len, 1); if (len < ((l + 7) / 8)) bgp_parse_error(s, 1); /* Decode MPLS labels */ if (s->mpls) bgp_decode_mpls_labels(s, &pos, &len, &l, a); if (l > IP4_MAX_PREFIX_LENGTH) bgp_parse_error(s, 10); /* Decode prefix body */ ip4_addr addr = IP4_NONE; uint b = (l + 7) / 8; memcpy(&addr, pos, b); ADVANCE(pos, len, b); net = NET_ADDR_IP4(ip4_ntoh(addr), l); net_normalize_ip4(&net); // XXXX validate prefix bgp_rte_update(s, (net_addr *) &net, path_id, a); } } static uint bgp_encode_nlri_ip6(struct bgp_write_state *s, struct bgp_bucket *buck, byte *buf, uint size) { byte *pos = buf; while (!EMPTY_LIST(buck->prefixes) && (size >= BGP_NLRI_MAX)) { struct bgp_prefix *px = HEAD(buck->prefixes); struct net_addr_ip6 *net = (void *) px->net; /* Encode path ID */ if (s->add_path) { put_u32(pos, px->path_id); ADVANCE(pos, size, 4); } /* Encode prefix length */ *pos = net->pxlen; ADVANCE(pos, size, 1); /* Encode MPLS labels */ if (s->mpls) bgp_encode_mpls_labels(s, s->mpls_labels, &pos, &size, pos - 1); /* Encode prefix body */ ip6_addr a = ip6_hton(net->prefix); uint b = (net->pxlen + 7) / 8; memcpy(pos, &a, b); ADVANCE(pos, size, b); bgp_free_prefix(s->channel, px); } return pos - buf; } static void bgp_decode_nlri_ip6(struct bgp_parse_state *s, byte *pos, uint len, rta *a) { while (len) { net_addr_ip6 net; u32 path_id = 0; /* Decode path ID */ if (s->add_path) { if (len < 5) bgp_parse_error(s, 1); path_id = get_u32(pos); ADVANCE(pos, len, 4); } /* Decode prefix length */ uint l = *pos; ADVANCE(pos, len, 1); if (len < ((l + 7) / 8)) bgp_parse_error(s, 1); /* Decode MPLS labels */ if (s->mpls) bgp_decode_mpls_labels(s, &pos, &len, &l, a); if (l > IP6_MAX_PREFIX_LENGTH) bgp_parse_error(s, 10); /* Decode prefix body */ ip6_addr addr = IP6_NONE; uint b = (l + 7) / 8; memcpy(&addr, pos, b); ADVANCE(pos, len, b); net = NET_ADDR_IP6(ip6_ntoh(addr), l); net_normalize_ip6(&net); // XXXX validate prefix bgp_rte_update(s, (net_addr *) &net, path_id, a); } } static uint bgp_encode_nlri_vpn4(struct bgp_write_state *s, struct bgp_bucket *buck, byte *buf, uint size) { byte *pos = buf; while (!EMPTY_LIST(buck->prefixes) && (size >= BGP_NLRI_MAX)) { struct bgp_prefix *px = HEAD(buck->prefixes); struct net_addr_vpn4 *net = (void *) px->net; /* Encode path ID */ if (s->add_path) { put_u32(pos, px->path_id); ADVANCE(pos, size, 4); } /* Encode prefix length */ *pos = 64 + net->pxlen; ADVANCE(pos, size, 1); /* Encode MPLS labels */ if (s->mpls) bgp_encode_mpls_labels(s, s->mpls_labels, &pos, &size, pos - 1); /* Encode route distinguisher */ put_u64(pos, net->rd); ADVANCE(pos, size, 8); /* Encode prefix body */ ip4_addr a = ip4_hton(net->prefix); uint b = (net->pxlen + 7) / 8; memcpy(pos, &a, b); ADVANCE(pos, size, b); bgp_free_prefix(s->channel, px); } return pos - buf; } static void bgp_decode_nlri_vpn4(struct bgp_parse_state *s, byte *pos, uint len, rta *a) { while (len) { net_addr_vpn4 net; u32 path_id = 0; /* Decode path ID */ if (s->add_path) { if (len < 5) bgp_parse_error(s, 1); path_id = get_u32(pos); ADVANCE(pos, len, 4); } /* Decode prefix length */ uint l = *pos; ADVANCE(pos, len, 1); if (len < ((l + 7) / 8)) bgp_parse_error(s, 1); /* Decode MPLS labels */ if (s->mpls) bgp_decode_mpls_labels(s, &pos, &len, &l, a); /* Decode route distinguisher */ if (l < 64) bgp_parse_error(s, 1); u64 rd = get_u64(pos); ADVANCE(pos, len, 8); l -= 64; if (l > IP4_MAX_PREFIX_LENGTH) bgp_parse_error(s, 10); /* Decode prefix body */ ip4_addr addr = IP4_NONE; uint b = (l + 7) / 8; memcpy(&addr, pos, b); ADVANCE(pos, len, b); net = NET_ADDR_VPN4(ip4_ntoh(addr), l, rd); net_normalize_vpn4(&net); // XXXX validate prefix bgp_rte_update(s, (net_addr *) &net, path_id, a); } } static uint bgp_encode_nlri_vpn6(struct bgp_write_state *s, struct bgp_bucket *buck, byte *buf, uint size) { byte *pos = buf; while (!EMPTY_LIST(buck->prefixes) && (size >= BGP_NLRI_MAX)) { struct bgp_prefix *px = HEAD(buck->prefixes); struct net_addr_vpn6 *net = (void *) px->net; /* Encode path ID */ if (s->add_path) { put_u32(pos, px->path_id); ADVANCE(pos, size, 4); } /* Encode prefix length */ *pos = 64 + net->pxlen; ADVANCE(pos, size, 1); /* Encode MPLS labels */ if (s->mpls) bgp_encode_mpls_labels(s, s->mpls_labels, &pos, &size, pos - 1); /* Encode route distinguisher */ put_u64(pos, net->rd); ADVANCE(pos, size, 8); /* Encode prefix body */ ip6_addr a = ip6_hton(net->prefix); uint b = (net->pxlen + 7) / 8; memcpy(pos, &a, b); ADVANCE(pos, size, b); bgp_free_prefix(s->channel, px); } return pos - buf; } static void bgp_decode_nlri_vpn6(struct bgp_parse_state *s, byte *pos, uint len, rta *a) { while (len) { net_addr_vpn6 net; u32 path_id = 0; /* Decode path ID */ if (s->add_path) { if (len < 5) bgp_parse_error(s, 1); path_id = get_u32(pos); ADVANCE(pos, len, 4); } /* Decode prefix length */ uint l = *pos; ADVANCE(pos, len, 1); if (len < ((l + 7) / 8)) bgp_parse_error(s, 1); /* Decode MPLS labels */ if (s->mpls) bgp_decode_mpls_labels(s, &pos, &len, &l, a); /* Decode route distinguisher */ if (l < 64) bgp_parse_error(s, 1); u64 rd = get_u64(pos); ADVANCE(pos, len, 8); l -= 64; if (l > IP6_MAX_PREFIX_LENGTH) bgp_parse_error(s, 10); /* Decode prefix body */ ip6_addr addr = IP6_NONE; uint b = (l + 7) / 8; memcpy(&addr, pos, b); ADVANCE(pos, len, b); net = NET_ADDR_VPN6(ip6_ntoh(addr), l, rd); net_normalize_vpn6(&net); // XXXX validate prefix bgp_rte_update(s, (net_addr *) &net, path_id, a); } } static uint bgp_encode_nlri_flow4(struct bgp_write_state *s, struct bgp_bucket *buck, byte *buf, uint size) { byte *pos = buf; while (!EMPTY_LIST(buck->prefixes) && (size >= 4)) { struct bgp_prefix *px = HEAD(buck->prefixes); struct net_addr_flow4 *net = (void *) px->net; uint flen = net->length - sizeof(net_addr_flow4); /* Encode path ID */ if (s->add_path) { put_u32(pos, px->path_id); ADVANCE(pos, size, 4); } if (flen > size) break; /* Copy whole flow data including length */ memcpy(pos, net->data, flen); ADVANCE(pos, size, flen); bgp_free_prefix(s->channel, px); } return pos - buf; } static void bgp_decode_nlri_flow4(struct bgp_parse_state *s, byte *pos, uint len, rta *a) { while (len) { u32 path_id = 0; /* Decode path ID */ if (s->add_path) { if (len < 4) bgp_parse_error(s, 1); path_id = get_u32(pos); ADVANCE(pos, len, 4); } if (len < 2) bgp_parse_error(s, 1); /* Decode flow length */ uint hlen = flow_hdr_length(pos); uint dlen = flow_read_length(pos); uint flen = hlen + dlen; byte *data = pos + hlen; if (len < flen) bgp_parse_error(s, 1); /* Validate flow data */ enum flow_validated_state r = flow4_validate(data, dlen); if (r != FLOW_ST_VALID) { log(L_REMOTE "%s: Invalid flow route: %s", s->proto->p.name, flow_validated_state_str(r)); bgp_parse_error(s, 1); } ip4_addr px = IP4_NONE; uint pxlen = 0; /* Decode dst prefix */ if (data[0] == FLOW_TYPE_DST_PREFIX) { px = flow_read_ip4_part(data); pxlen = flow_read_pxlen(data); } /* Prepare the flow */ net_addr *n = alloca(sizeof(struct net_addr_flow4) + flen); net_fill_flow4(n, px, pxlen, pos, flen); ADVANCE(pos, len, flen); /* Apply validation procedure per RFC 8955 (6) */ if (a && s->channel->cf->validate) bgp_apply_flow_validation(s, n, a); bgp_rte_update(s, n, path_id, a); } } static uint bgp_encode_nlri_flow6(struct bgp_write_state *s, struct bgp_bucket *buck, byte *buf, uint size) { byte *pos = buf; while (!EMPTY_LIST(buck->prefixes) && (size >= 4)) { struct bgp_prefix *px = HEAD(buck->prefixes); struct net_addr_flow6 *net = (void *) px->net; uint flen = net->length - sizeof(net_addr_flow6); /* Encode path ID */ if (s->add_path) { put_u32(pos, px->path_id); ADVANCE(pos, size, 4); } if (flen > size) break; /* Copy whole flow data including length */ memcpy(pos, net->data, flen); ADVANCE(pos, size, flen); bgp_free_prefix(s->channel, px); } return pos - buf; } static void bgp_decode_nlri_flow6(struct bgp_parse_state *s, byte *pos, uint len, rta *a) { while (len) { u32 path_id = 0; /* Decode path ID */ if (s->add_path) { if (len < 4) bgp_parse_error(s, 1); path_id = get_u32(pos); ADVANCE(pos, len, 4); } if (len < 2) bgp_parse_error(s, 1); /* Decode flow length */ uint hlen = flow_hdr_length(pos); uint dlen = flow_read_length(pos); uint flen = hlen + dlen; byte *data = pos + hlen; if (len < flen) bgp_parse_error(s, 1); /* Validate flow data */ enum flow_validated_state r = flow6_validate(data, dlen); if (r != FLOW_ST_VALID) { log(L_REMOTE "%s: Invalid flow route: %s", s->proto->p.name, flow_validated_state_str(r)); bgp_parse_error(s, 1); } ip6_addr px = IP6_NONE; uint pxlen = 0; /* Decode dst prefix */ if (data[0] == FLOW_TYPE_DST_PREFIX) { px = flow_read_ip6_part(data); pxlen = flow_read_pxlen(data); } /* Prepare the flow */ net_addr *n = alloca(sizeof(struct net_addr_flow6) + flen); net_fill_flow6(n, px, pxlen, pos, flen); ADVANCE(pos, len, flen); /* Apply validation procedure per RFC 8955 (6) */ if (a && s->channel->cf->validate) bgp_apply_flow_validation(s, n, a); bgp_rte_update(s, n, path_id, a); } } static const struct bgp_af_desc bgp_af_table[] = { { .afi = BGP_AF_IPV4, .net = NET_IP4, .name = "ipv4", .encode_nlri = bgp_encode_nlri_ip4, .decode_nlri = bgp_decode_nlri_ip4, .encode_next_hop = bgp_encode_next_hop_ip, .decode_next_hop = bgp_decode_next_hop_ip, .update_next_hop = bgp_update_next_hop_ip, }, { .afi = BGP_AF_IPV4_MC, .net = NET_IP4, .name = "ipv4-mc", .encode_nlri = bgp_encode_nlri_ip4, .decode_nlri = bgp_decode_nlri_ip4, .encode_next_hop = bgp_encode_next_hop_ip, .decode_next_hop = bgp_decode_next_hop_ip, .update_next_hop = bgp_update_next_hop_ip, }, { .afi = BGP_AF_IPV4_MPLS, .net = NET_IP4, .mpls = 1, .name = "ipv4-mpls", .encode_nlri = bgp_encode_nlri_ip4, .decode_nlri = bgp_decode_nlri_ip4, .encode_next_hop = bgp_encode_next_hop_ip, .decode_next_hop = bgp_decode_next_hop_ip, .update_next_hop = bgp_update_next_hop_ip, }, { .afi = BGP_AF_IPV6, .net = NET_IP6, .name = "ipv6", .encode_nlri = bgp_encode_nlri_ip6, .decode_nlri = bgp_decode_nlri_ip6, .encode_next_hop = bgp_encode_next_hop_ip, .decode_next_hop = bgp_decode_next_hop_ip, .update_next_hop = bgp_update_next_hop_ip, }, { .afi = BGP_AF_IPV6_MC, .net = NET_IP6, .name = "ipv6-mc", .encode_nlri = bgp_encode_nlri_ip6, .decode_nlri = bgp_decode_nlri_ip6, .encode_next_hop = bgp_encode_next_hop_ip, .decode_next_hop = bgp_decode_next_hop_ip, .update_next_hop = bgp_update_next_hop_ip, }, { .afi = BGP_AF_IPV6_MPLS, .net = NET_IP6, .mpls = 1, .name = "ipv6-mpls", .encode_nlri = bgp_encode_nlri_ip6, .decode_nlri = bgp_decode_nlri_ip6, .encode_next_hop = bgp_encode_next_hop_ip, .decode_next_hop = bgp_decode_next_hop_ip, .update_next_hop = bgp_update_next_hop_ip, }, { .afi = BGP_AF_VPN4_MPLS, .net = NET_VPN4, .mpls = 1, .name = "vpn4-mpls", .encode_nlri = bgp_encode_nlri_vpn4, .decode_nlri = bgp_decode_nlri_vpn4, .encode_next_hop = bgp_encode_next_hop_vpn, .decode_next_hop = bgp_decode_next_hop_vpn, .update_next_hop = bgp_update_next_hop_ip, }, { .afi = BGP_AF_VPN6_MPLS, .net = NET_VPN6, .mpls = 1, .name = "vpn6-mpls", .encode_nlri = bgp_encode_nlri_vpn6, .decode_nlri = bgp_decode_nlri_vpn6, .encode_next_hop = bgp_encode_next_hop_vpn, .decode_next_hop = bgp_decode_next_hop_vpn, .update_next_hop = bgp_update_next_hop_ip, }, { .afi = BGP_AF_VPN4_MC, .net = NET_VPN4, .name = "vpn4-mc", .encode_nlri = bgp_encode_nlri_vpn4, .decode_nlri = bgp_decode_nlri_vpn4, .encode_next_hop = bgp_encode_next_hop_vpn, .decode_next_hop = bgp_decode_next_hop_vpn, .update_next_hop = bgp_update_next_hop_ip, }, { .afi = BGP_AF_VPN6_MC, .net = NET_VPN6, .name = "vpn6-mc", .encode_nlri = bgp_encode_nlri_vpn6, .decode_nlri = bgp_decode_nlri_vpn6, .encode_next_hop = bgp_encode_next_hop_vpn, .decode_next_hop = bgp_decode_next_hop_vpn, .update_next_hop = bgp_update_next_hop_ip, }, { .afi = BGP_AF_FLOW4, .net = NET_FLOW4, .no_igp = 1, .name = "flow4", .encode_nlri = bgp_encode_nlri_flow4, .decode_nlri = bgp_decode_nlri_flow4, .encode_next_hop = bgp_encode_next_hop_none, .decode_next_hop = bgp_decode_next_hop_none, .update_next_hop = bgp_update_next_hop_none, }, { .afi = BGP_AF_FLOW6, .net = NET_FLOW6, .no_igp = 1, .name = "flow6", .encode_nlri = bgp_encode_nlri_flow6, .decode_nlri = bgp_decode_nlri_flow6, .encode_next_hop = bgp_encode_next_hop_none, .decode_next_hop = bgp_decode_next_hop_none, .update_next_hop = bgp_update_next_hop_none, }, }; const struct bgp_af_desc * bgp_get_af_desc(u32 afi) { uint i; for (i = 0; i < ARRAY_SIZE(bgp_af_table); i++) if (bgp_af_table[i].afi == afi) return &bgp_af_table[i]; return NULL; } static inline uint bgp_encode_nlri(struct bgp_write_state *s, struct bgp_bucket *buck, byte *buf, byte *end) { return s->channel->desc->encode_nlri(s, buck, buf, end - buf); } static inline uint bgp_encode_next_hop(struct bgp_write_state *s, eattr *nh, byte *buf) { return s->channel->desc->encode_next_hop(s, nh, buf, 255); } void bgp_update_next_hop(struct bgp_export_state *s, eattr *a, ea_list **to) { s->channel->desc->update_next_hop(s, a, to); } #define MAX_ATTRS_LENGTH (end-buf+BGP_HEADER_LENGTH - 1024) static byte * bgp_create_ip_reach(struct bgp_write_state *s, struct bgp_bucket *buck, byte *buf, byte *end) { /* * 2 B Withdrawn Routes Length (zero) * --- IPv4 Withdrawn Routes NLRI (unused) * 2 B Total Path Attribute Length * var Path Attributes * var IPv4 Network Layer Reachability Information */ int lr, la; la = bgp_encode_attrs(s, buck->eattrs, buf+4, buf + MAX_ATTRS_LENGTH); if (la < 0) { /* Attribute list too long */ bgp_withdraw_bucket(s->channel, buck); return NULL; } put_u16(buf+0, 0); put_u16(buf+2, la); lr = bgp_encode_nlri(s, buck, buf+4+la, end); return buf+4+la+lr; } static byte * bgp_create_mp_reach(struct bgp_write_state *s, struct bgp_bucket *buck, byte *buf, byte *end) { /* * 2 B IPv4 Withdrawn Routes Length (zero) * --- IPv4 Withdrawn Routes NLRI (unused) * 2 B Total Path Attribute Length * 1 B MP_REACH_NLRI hdr - Attribute Flags * 1 B MP_REACH_NLRI hdr - Attribute Type Code * 2 B MP_REACH_NLRI hdr - Length of Attribute Data * 2 B MP_REACH_NLRI data - Address Family Identifier * 1 B MP_REACH_NLRI data - Subsequent Address Family Identifier * 1 B MP_REACH_NLRI data - Length of Next Hop Network Address * var MP_REACH_NLRI data - Network Address of Next Hop * 1 B MP_REACH_NLRI data - Reserved (zero) * var MP_REACH_NLRI data - Network Layer Reachability Information * var Rest of Path Attributes * --- IPv4 Network Layer Reachability Information (unused) */ int lh, lr, la; /* Lengths of next hop, NLRI and attributes */ /* Begin of MP_REACH_NLRI atribute */ buf[4] = BAF_OPTIONAL | BAF_EXT_LEN; buf[5] = BA_MP_REACH_NLRI; put_u16(buf+6, 0); /* Will be fixed later */ put_af3(buf+8, s->channel->afi); byte *pos = buf+11; /* Encode attributes to temporary buffer */ byte *abuf = alloca(MAX_ATTRS_LENGTH); la = bgp_encode_attrs(s, buck->eattrs, abuf, abuf + MAX_ATTRS_LENGTH); if (la < 0) { /* Attribute list too long */ bgp_withdraw_bucket(s->channel, buck); return NULL; } /* Encode the next hop */ lh = bgp_encode_next_hop(s, s->mp_next_hop, pos+1); *pos = lh; pos += 1+lh; /* Reserved field */ *pos++ = 0; /* Encode the NLRI */ lr = bgp_encode_nlri(s, buck, pos, end - la); pos += lr; /* End of MP_REACH_NLRI atribute, update data length */ put_u16(buf+6, pos-buf-8); /* Copy remaining attributes */ memcpy(pos, abuf, la); pos += la; /* Initial UPDATE fields */ put_u16(buf+0, 0); put_u16(buf+2, pos-buf-4); return pos; } #undef MAX_ATTRS_LENGTH static byte * bgp_create_ip_unreach(struct bgp_write_state *s, struct bgp_bucket *buck, byte *buf, byte *end) { /* * 2 B Withdrawn Routes Length * var IPv4 Withdrawn Routes NLRI * 2 B Total Path Attribute Length (zero) * --- Path Attributes (unused) * --- IPv4 Network Layer Reachability Information (unused) */ uint len = bgp_encode_nlri(s, buck, buf+2, end); put_u16(buf+0, len); put_u16(buf+2+len, 0); return buf+4+len; } static byte * bgp_create_mp_unreach(struct bgp_write_state *s, struct bgp_bucket *buck, byte *buf, byte *end) { /* * 2 B Withdrawn Routes Length (zero) * --- IPv4 Withdrawn Routes NLRI (unused) * 2 B Total Path Attribute Length * 1 B MP_UNREACH_NLRI hdr - Attribute Flags * 1 B MP_UNREACH_NLRI hdr - Attribute Type Code * 2 B MP_UNREACH_NLRI hdr - Length of Attribute Data * 2 B MP_UNREACH_NLRI data - Address Family Identifier * 1 B MP_UNREACH_NLRI data - Subsequent Address Family Identifier * var MP_UNREACH_NLRI data - Network Layer Reachability Information * --- IPv4 Network Layer Reachability Information (unused) */ uint len = bgp_encode_nlri(s, buck, buf+11, end); put_u16(buf+0, 0); put_u16(buf+2, 7+len); /* Begin of MP_UNREACH_NLRI atribute */ buf[4] = BAF_OPTIONAL | BAF_EXT_LEN; buf[5] = BA_MP_UNREACH_NLRI; put_u16(buf+6, 3+len); put_af3(buf+8, s->channel->afi); return buf+11+len; } static byte * bgp_create_update(struct bgp_channel *c, byte *buf) { struct bgp_proto *p = (void *) c->c.proto; struct bgp_bucket *buck; byte *end = buf + (bgp_max_packet_length(p->conn) - BGP_HEADER_LENGTH); byte *res = NULL; again: ; struct lp_state tmpp; lp_save(tmp_linpool, &tmpp); /* Initialize write state */ struct bgp_write_state s = { .proto = p, .channel = c, .pool = tmp_linpool, .mp_reach = (c->afi != BGP_AF_IPV4) || c->ext_next_hop, .as4_session = p->as4_session, .add_path = c->add_path_tx, .mpls = c->desc->mpls, }; /* Try unreachable bucket */ if ((buck = c->withdraw_bucket) && !EMPTY_LIST(buck->prefixes)) { res = (c->afi == BGP_AF_IPV4) && !c->ext_next_hop ? bgp_create_ip_unreach(&s, buck, buf, end): bgp_create_mp_unreach(&s, buck, buf, end); goto done; } /* Try reachable buckets */ if (!EMPTY_LIST(c->bucket_queue)) { buck = HEAD(c->bucket_queue); /* Cleanup empty buckets */ if (EMPTY_LIST(buck->prefixes)) { bgp_free_bucket(c, buck); lp_restore(tmp_linpool, &tmpp); goto again; } res = !s.mp_reach ? bgp_create_ip_reach(&s, buck, buf, end): bgp_create_mp_reach(&s, buck, buf, end); if (EMPTY_LIST(buck->prefixes)) bgp_free_bucket(c, buck); else bgp_defer_bucket(c, buck); if (!res) { lp_restore(tmp_linpool, &tmpp); goto again; } goto done; } /* No more prefixes to send */ return NULL; done: BGP_TRACE_RL(&rl_snd_update, D_PACKETS, "Sending UPDATE"); p->stats.tx_updates++; lp_restore(tmp_linpool, &tmpp); return res; } static byte * bgp_create_ip_end_mark(struct bgp_channel *c UNUSED, byte *buf) { /* Empty update packet */ put_u32(buf, 0); return buf+4; } static byte * bgp_create_mp_end_mark(struct bgp_channel *c, byte *buf) { put_u16(buf+0, 0); put_u16(buf+2, 6); /* length 4--9 */ /* Empty MP_UNREACH_NLRI atribute */ buf[4] = BAF_OPTIONAL; buf[5] = BA_MP_UNREACH_NLRI; buf[6] = 3; /* Length 7--9 */ put_af3(buf+7, c->afi); return buf+10; } static byte * bgp_create_end_mark(struct bgp_channel *c, byte *buf) { struct bgp_proto *p = (void *) c->c.proto; BGP_TRACE(D_PACKETS, "Sending END-OF-RIB"); p->stats.tx_updates++; return (c->afi == BGP_AF_IPV4) ? bgp_create_ip_end_mark(c, buf): bgp_create_mp_end_mark(c, buf); } static inline void bgp_rx_end_mark(struct bgp_parse_state *s, u32 afi) { struct bgp_proto *p = s->proto; struct bgp_channel *c = bgp_get_channel(p, afi); BGP_TRACE(D_PACKETS, "Got END-OF-RIB"); if (!c) DISCARD(BAD_AFI, BGP_AFI(afi), BGP_SAFI(afi)); if (c->load_state == BFS_LOADING) c->load_state = BFS_NONE; if (p->p.gr_recovery) channel_graceful_restart_unlock(&c->c); if (c->gr_active) bgp_graceful_restart_done(c); } static inline void bgp_decode_nlri(struct bgp_parse_state *s, u32 afi, byte *nlri, uint len, ea_list *ea, byte *nh, uint nh_len) { struct bgp_channel *c = bgp_get_channel(s->proto, afi); rta *a = NULL; if (!c) DISCARD(BAD_AFI, BGP_AFI(afi), BGP_SAFI(afi)); s->channel = c; s->add_path = c->add_path_rx; s->mpls = c->desc->mpls; s->last_id = 0; s->last_src = s->proto->p.main_source; /* * IPv4 BGP and MP-BGP may be used together in one update, therefore we do not * add BA_NEXT_HOP in bgp_decode_attrs(), but we add it here independently for * IPv4 BGP and MP-BGP. We undo the attribute (and possibly others attached by * decode_next_hop hooks) by restoring a->eattrs afterwards. */ if (ea) { a = allocz(RTA_MAX_SIZE); a->source = RTS_BGP; a->scope = SCOPE_UNIVERSE; a->from = s->proto->remote_ip; a->eattrs = ea; a->pref = c->c.preference; c->desc->decode_next_hop(s, nh, nh_len, a); bgp_finish_attrs(s, a); /* Handle withdraw during next hop decoding */ if (s->err_withdraw) a = NULL; } c->desc->decode_nlri(s, nlri, len, a); rta_free(s->cached_rta); s->cached_rta = NULL; } static void bgp_rx_update(struct bgp_conn *conn, byte *pkt, uint len) { struct bgp_proto *p = conn->bgp; ea_list *ea = NULL; BGP_TRACE_RL(&rl_rcv_update, D_PACKETS, "Got UPDATE"); p->last_rx_update = current_time(); p->stats.rx_updates++; /* Workaround for some BGP implementations that skip initial KEEPALIVE */ if (conn->state == BS_OPENCONFIRM) bgp_conn_enter_established_state(conn); if (conn->state != BS_ESTABLISHED) { bgp_error(conn, 5, fsm_err_subcode[conn->state], NULL, 0); return; } bgp_start_timer(conn->hold_timer, conn->hold_time); struct lp_state tmpp; lp_save(tmp_linpool, &tmpp); /* Initialize parse state */ struct bgp_parse_state s = { .proto = p, .pool = tmp_linpool, .as4_session = p->as4_session, }; /* Parse error handler */ if (setjmp(s.err_jmpbuf)) { bgp_error(conn, 3, s.err_subcode, NULL, 0); goto done; } /* Check minimal length */ if (len < 23) { bgp_error(conn, 1, 2, pkt+16, 2); return; } /* Skip fixed header */ uint pos = 19; /* * UPDATE message format * * 2 B IPv4 Withdrawn Routes Length * var IPv4 Withdrawn Routes NLRI * 2 B Total Path Attribute Length * var Path Attributes * var IPv4 Reachable Routes NLRI */ s.ip_unreach_len = get_u16(pkt + pos); s.ip_unreach_nlri = pkt + pos + 2; pos += 2 + s.ip_unreach_len; if (pos + 2 > len) bgp_parse_error(&s, 1); s.attr_len = get_u16(pkt + pos); s.attrs = pkt + pos + 2; pos += 2 + s.attr_len; if (pos > len) bgp_parse_error(&s, 1); s.ip_reach_len = len - pos; s.ip_reach_nlri = pkt + pos; if (s.attr_len) ea = bgp_decode_attrs(&s, s.attrs, s.attr_len); else ea = NULL; /* Check for End-of-RIB marker */ if (!s.attr_len && !s.ip_unreach_len && !s.ip_reach_len) { bgp_rx_end_mark(&s, BGP_AF_IPV4); goto done; } /* Check for MP End-of-RIB marker */ if ((s.attr_len < 8) && !s.ip_unreach_len && !s.ip_reach_len && !s.mp_reach_len && !s.mp_unreach_len && s.mp_unreach_af) { bgp_rx_end_mark(&s, s.mp_unreach_af); goto done; } if (s.ip_unreach_len) bgp_decode_nlri(&s, BGP_AF_IPV4, s.ip_unreach_nlri, s.ip_unreach_len, NULL, NULL, 0); if (s.mp_unreach_len) bgp_decode_nlri(&s, s.mp_unreach_af, s.mp_unreach_nlri, s.mp_unreach_len, NULL, NULL, 0); s.reach_nlri_step = 1; if (s.ip_reach_len) bgp_decode_nlri(&s, BGP_AF_IPV4, s.ip_reach_nlri, s.ip_reach_len, ea, s.ip_next_hop_data, s.ip_next_hop_len); if (s.mp_reach_len) bgp_decode_nlri(&s, s.mp_reach_af, s.mp_reach_nlri, s.mp_reach_len, ea, s.mp_next_hop_data, s.mp_next_hop_len); done: rta_free(s.cached_rta); lp_restore(tmp_linpool, &tmpp); return; } static uint bgp_find_update_afi(byte *pos, uint len) { /* * This is stripped-down version of bgp_rx_update(), bgp_decode_attrs() and * bgp_decode_mp_[un]reach_nlri() used by MRT code in order to find out which * AFI/SAFI is associated with incoming UPDATE. Returns 0 for framing errors. */ if (len < 23) return 0; /* Assume there is no withrawn NLRI, read lengths and move to attribute list */ uint wlen = get_u16(pos + 19); uint alen = get_u16(pos + 21); ADVANCE(pos, len, 23); /* Either non-zero withdrawn NLRI, non-zero reachable NLRI, or IPv4 End-of-RIB */ if ((wlen != 0) || (alen < len) || !alen) return BGP_AF_IPV4; if (alen > len) return 0; /* Process attribute list (alen == len) */ while (len) { if (len < 2) return 0; uint flags = pos[0]; uint code = pos[1]; ADVANCE(pos, len, 2); uint ll = !(flags & BAF_EXT_LEN) ? 1 : 2; if (len < ll) return 0; /* Read attribute length and move to attribute body */ alen = (ll == 1) ? get_u8(pos) : get_u16(pos); ADVANCE(pos, len, ll); if (len < alen) return 0; /* Found MP NLRI */ if ((code == BA_MP_REACH_NLRI) || (code == BA_MP_UNREACH_NLRI)) { if (alen < 3) return 0; return BGP_AF(get_u16(pos), pos[2]); } /* Move to the next attribute */ ADVANCE(pos, len, alen); } /* No basic or MP NLRI, but there are some attributes -> error */ return 0; } /* * ROUTE-REFRESH */ static inline byte * bgp_create_route_refresh(struct bgp_channel *c, byte *buf) { struct bgp_proto *p = (void *) c->c.proto; BGP_TRACE(D_PACKETS, "Sending ROUTE-REFRESH"); /* Original route refresh request, RFC 2918 */ put_af4(buf, c->afi); buf[2] = BGP_RR_REQUEST; return buf+4; } static inline byte * bgp_create_begin_refresh(struct bgp_channel *c, byte *buf) { struct bgp_proto *p = (void *) c->c.proto; BGP_TRACE(D_PACKETS, "Sending BEGIN-OF-RR"); /* Demarcation of beginning of route refresh (BoRR), RFC 7313 */ put_af4(buf, c->afi); buf[2] = BGP_RR_BEGIN; return buf+4; } static inline byte * bgp_create_end_refresh(struct bgp_channel *c, byte *buf) { struct bgp_proto *p = (void *) c->c.proto; BGP_TRACE(D_PACKETS, "Sending END-OF-RR"); /* Demarcation of ending of route refresh (EoRR), RFC 7313 */ put_af4(buf, c->afi); buf[2] = BGP_RR_END; return buf+4; } static void bgp_rx_route_refresh(struct bgp_conn *conn, byte *pkt, uint len) { struct bgp_proto *p = conn->bgp; if (conn->state != BS_ESTABLISHED) { bgp_error(conn, 5, fsm_err_subcode[conn->state], NULL, 0); return; } if (!conn->local_caps->route_refresh) { bgp_error(conn, 1, 3, pkt+18, 1); return; } if (len < (BGP_HEADER_LENGTH + 4)) { bgp_error(conn, 1, 2, pkt+16, 2); return; } if (len > (BGP_HEADER_LENGTH + 4)) { bgp_error(conn, 7, 1, pkt, MIN(len, 2048)); return; } struct bgp_channel *c = bgp_get_channel(p, get_af4(pkt+19)); if (!c) { log(L_WARN "%s: Got ROUTE-REFRESH subtype %u for AF %u.%u, ignoring", p->p.name, pkt[21], get_u16(pkt+19), pkt[22]); return; } /* RFC 7313 redefined reserved field as RR message subtype */ uint subtype = p->enhanced_refresh ? pkt[21] : BGP_RR_REQUEST; switch (subtype) { case BGP_RR_REQUEST: BGP_TRACE(D_PACKETS, "Got ROUTE-REFRESH"); channel_request_feeding(&c->c); break; case BGP_RR_BEGIN: BGP_TRACE(D_PACKETS, "Got BEGIN-OF-RR"); bgp_refresh_begin(c); break; case BGP_RR_END: BGP_TRACE(D_PACKETS, "Got END-OF-RR"); bgp_refresh_end(c); break; default: log(L_WARN "%s: Got ROUTE-REFRESH message with unknown subtype %u, ignoring", p->p.name, subtype); break; } } static inline struct bgp_channel * bgp_get_channel_to_send(struct bgp_proto *p, struct bgp_conn *conn) { uint i = conn->last_channel; /* Try the last channel, but at most several times */ if ((conn->channels_to_send & (1 << i)) && (conn->last_channel_count < 16)) goto found; /* Find channel with non-zero channels_to_send */ do { i++; if (i >= p->channel_count) i = 0; } while (! (conn->channels_to_send & (1 << i))); /* Use that channel */ conn->last_channel = i; conn->last_channel_count = 0; found: conn->last_channel_count++; return p->channel_map[i]; } static inline int bgp_send(struct bgp_conn *conn, uint type, uint len) { sock *sk = conn->sk; byte *buf = sk->tbuf; conn->bgp->stats.tx_messages++; conn->bgp->stats.tx_bytes += len; memset(buf, 0xff, 16); /* Marker */ put_u16(buf+16, len); buf[18] = type; return sk_send(sk, len); } /** * bgp_fire_tx - transmit packets * @conn: connection * * Whenever the transmit buffers of the underlying TCP connection * are free and we have any packets queued for sending, the socket functions * call bgp_fire_tx() which takes care of selecting the highest priority packet * queued (Notification > Keepalive > Open > Update), assembling its header * and body and sending it to the connection. */ static int bgp_fire_tx(struct bgp_conn *conn) { struct bgp_proto *p = conn->bgp; struct bgp_channel *c; byte *buf, *pkt, *end; uint s; if (!conn->sk) return 0; buf = conn->sk->tbuf; pkt = buf + BGP_HEADER_LENGTH; s = conn->packets_to_send; if (s & (1 << PKT_SCHEDULE_CLOSE)) { /* We can finally close connection and enter idle state */ bgp_conn_enter_idle_state(conn); return 0; } if (s & (1 << PKT_NOTIFICATION)) { conn->packets_to_send = 1 << PKT_SCHEDULE_CLOSE; end = bgp_create_notification(conn, pkt); return bgp_send(conn, PKT_NOTIFICATION, end - buf); } else if (s & (1 << PKT_OPEN)) { conn->packets_to_send &= ~(1 << PKT_OPEN); end = bgp_create_open(conn, pkt); return bgp_send(conn, PKT_OPEN, end - buf); } else if (s & (1 << PKT_KEEPALIVE)) { conn->packets_to_send &= ~(1 << PKT_KEEPALIVE); BGP_TRACE(D_PACKETS, "Sending KEEPALIVE"); bgp_start_timer(conn->keepalive_timer, conn->keepalive_time); return bgp_send(conn, PKT_KEEPALIVE, BGP_HEADER_LENGTH); } else while (conn->channels_to_send) { c = bgp_get_channel_to_send(p, conn); s = c->packets_to_send; if (s & (1 << PKT_ROUTE_REFRESH)) { c->packets_to_send &= ~(1 << PKT_ROUTE_REFRESH); end = bgp_create_route_refresh(c, pkt); return bgp_send(conn, PKT_ROUTE_REFRESH, end - buf); } else if (s & (1 << PKT_BEGIN_REFRESH)) { /* BoRR is a subtype of RR, but uses separate bit in packets_to_send */ c->packets_to_send &= ~(1 << PKT_BEGIN_REFRESH); end = bgp_create_begin_refresh(c, pkt); return bgp_send(conn, PKT_ROUTE_REFRESH, end - buf); } else if (s & (1 << PKT_UPDATE)) { end = bgp_create_update(c, pkt); if (end) return bgp_send(conn, PKT_UPDATE, end - buf); /* No update to send, perhaps we need to send End-of-RIB or EoRR */ c->packets_to_send = 0; conn->channels_to_send &= ~(1 << c->index); if (c->feed_state == BFS_LOADED) { c->feed_state = BFS_NONE; end = bgp_create_end_mark(c, pkt); return bgp_send(conn, PKT_UPDATE, end - buf); } else if (c->feed_state == BFS_REFRESHED) { c->feed_state = BFS_NONE; end = bgp_create_end_refresh(c, pkt); return bgp_send(conn, PKT_ROUTE_REFRESH, end - buf); } } else if (s) bug("Channel packets_to_send: %x", s); c->packets_to_send = 0; conn->channels_to_send &= ~(1 << c->index); } return 0; } /** * bgp_schedule_packet - schedule a packet for transmission * @conn: connection * @c: channel * @type: packet type * * Schedule a packet of type @type to be sent as soon as possible. */ void bgp_schedule_packet(struct bgp_conn *conn, struct bgp_channel *c, int type) { ASSERT(conn->sk); DBG("BGP: Scheduling packet type %d\n", type); if (c) { if (! conn->channels_to_send) { conn->last_channel = c->index; conn->last_channel_count = 0; } c->packets_to_send |= 1 << type; conn->channels_to_send |= 1 << c->index; } else conn->packets_to_send |= 1 << type; if ((conn->sk->tpos == conn->sk->tbuf) && !ev_active(conn->tx_ev)) ev_schedule(conn->tx_ev); } void bgp_kick_tx(void *vconn) { struct bgp_conn *conn = vconn; DBG("BGP: kicking TX\n"); uint max = 1024; while (--max && (bgp_fire_tx(conn) > 0)) ; if (!max && !ev_active(conn->tx_ev)) ev_schedule(conn->tx_ev); } void bgp_tx(sock *sk) { struct bgp_conn *conn = sk->data; DBG("BGP: TX hook\n"); uint max = 1024; while (--max && (bgp_fire_tx(conn) > 0)) ; if (!max && !ev_active(conn->tx_ev)) ev_schedule(conn->tx_ev); } static struct { byte major, minor; byte *msg; } bgp_msg_table[] = { { 1, 0, "Invalid message header" }, { 1, 1, "Connection not synchronized" }, { 1, 2, "Bad message length" }, { 1, 3, "Bad message type" }, { 2, 0, "Invalid OPEN message" }, { 2, 1, "Unsupported version number" }, { 2, 2, "Bad peer AS" }, { 2, 3, "Bad BGP identifier" }, { 2, 4, "Unsupported optional parameter" }, { 2, 5, "Authentication failure" }, { 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" }, { 3, 3, "Missing mandatory attribute" }, { 3, 4, "Invalid attribute flags" }, { 3, 5, "Invalid attribute length" }, { 3, 6, "Invalid ORIGIN attribute" }, { 3, 7, "AS routing loop" }, /* Deprecated */ { 3, 8, "Invalid NEXT_HOP attribute" }, { 3, 9, "Optional attribute error" }, { 3, 10, "Invalid network field" }, { 3, 11, "Malformed AS_PATH" }, { 4, 0, "Hold timer expired" }, { 5, 0, "Finite state machine error" }, /* Subcodes are according to [RFC6608] */ { 5, 1, "Unexpected message in OpenSent state" }, { 5, 2, "Unexpected message in OpenConfirm state" }, { 5, 3, "Unexpected message in Established state" }, { 6, 0, "Cease" }, /* Subcodes are according to [RFC4486] */ { 6, 1, "Maximum number of prefixes reached" }, { 6, 2, "Administrative shutdown" }, { 6, 3, "Peer de-configured" }, { 6, 4, "Administrative reset" }, { 6, 5, "Connection rejected" }, { 6, 6, "Other configuration change" }, { 6, 7, "Connection collision resolution" }, { 6, 8, "Out of Resources" }, { 7, 0, "Invalid ROUTE-REFRESH message" }, /* [RFC7313] */ { 7, 1, "Invalid ROUTE-REFRESH message length" } /* [RFC7313] */ }; /** * bgp_error_dsc - return BGP error description * @code: BGP error code * @subcode: BGP error subcode * * bgp_error_dsc() returns error description for BGP errors * which might be static string or given temporary buffer. */ const char * bgp_error_dsc(uint code, uint subcode) { static char buff[32]; uint i; for (i=0; i < ARRAY_SIZE(bgp_msg_table); i++) if (bgp_msg_table[i].major == code && bgp_msg_table[i].minor == subcode) return bgp_msg_table[i].msg; bsprintf(buff, "Unknown error %u.%u", code, subcode); return buff; } /* RFC 8203 - shutdown communication message */ static int bgp_handle_message(struct bgp_proto *p, byte *data, uint len, byte **bp) { byte *msg = data + 1; uint msg_len = data[0]; uint i; /* Handle zero length message */ if (msg_len == 0) return 1; /* Handle proper message */ if (msg_len + 1 > len) return 0; /* Some elementary cleanup */ for (i = 0; i < msg_len; i++) if (msg[i] < ' ') msg[i] = ' '; proto_set_message(&p->p, msg, msg_len); *bp += bsprintf(*bp, ": \"%s\"", p->p.message); return 1; } void bgp_log_error(struct bgp_proto *p, u8 class, char *msg, uint code, uint subcode, byte *data, uint len) { byte argbuf[256+16], *t = argbuf; uint i; /* Don't report Cease messages generated by myself */ if (code == 6 && class == BE_BGP_TX) return; /* Reset shutdown message */ if ((code == 6) && ((subcode == 2) || (subcode == 4))) proto_set_message(&p->p, NULL, 0); if (len) { /* Bad peer AS / unacceptable hold time - print the value as decimal number */ if ((code == 2) && ((subcode == 2) || (subcode == 6)) && ((len == 2) || (len == 4))) { t += bsprintf(t, ": %u", (len == 2) ? get_u16(data) : get_u32(data)); goto done; } /* RFC 8203 - shutdown communication */ if (((code == 6) && ((subcode == 2) || (subcode == 4)))) if (bgp_handle_message(p, data, len, &t)) goto done; *t++ = ':'; *t++ = ' '; if (len > 16) len = 16; for (i=0; ip.name, msg, dsc, argbuf); } static void bgp_rx_notification(struct bgp_conn *conn, byte *pkt, uint len) { struct bgp_proto *p = conn->bgp; if (len < 21) { bgp_error(conn, 1, 2, pkt+16, 2); return; } uint code = pkt[19]; uint subcode = pkt[20]; int err = (code != 6); bgp_log_error(p, BE_BGP_RX, "Received", code, subcode, pkt+21, len-21); bgp_store_error(p, conn, BE_BGP_RX, (code << 16) | subcode); bgp_conn_enter_close_state(conn); bgp_schedule_packet(conn, NULL, PKT_SCHEDULE_CLOSE); if (err) { bgp_update_startup_delay(p); bgp_stop(p, 0, NULL, 0); } else { uint subcode_bit = 1 << ((subcode <= 8) ? subcode : 0); if (p->cf->disable_after_cease & subcode_bit) { log(L_INFO "%s: Disabled after Cease notification", p->p.name); p->startup_delay = 0; p->p.disabled = 1; } } } static void bgp_rx_keepalive(struct bgp_conn *conn) { struct bgp_proto *p = conn->bgp; BGP_TRACE(D_PACKETS, "Got KEEPALIVE"); bgp_start_timer(conn->hold_timer, conn->hold_time); if (conn->state == BS_OPENCONFIRM) { bgp_conn_enter_established_state(conn); return; } if (conn->state != BS_ESTABLISHED) bgp_error(conn, 5, fsm_err_subcode[conn->state], NULL, 0); } /** * bgp_rx_packet - handle a received packet * @conn: BGP connection * @pkt: start of the packet * @len: packet size * * bgp_rx_packet() takes a newly received packet and calls the corresponding * packet handler according to the packet type. */ static void bgp_rx_packet(struct bgp_conn *conn, byte *pkt, uint len) { byte type = pkt[18]; DBG("BGP: Got packet %02x (%d bytes)\n", type, len); conn->bgp->stats.rx_messages++; conn->bgp->stats.rx_bytes += len; if (conn->bgp->p.mrtdump & MD_MESSAGES) bgp_dump_message(conn, pkt, len); switch (type) { case PKT_OPEN: return bgp_rx_open(conn, pkt, len); case PKT_UPDATE: return bgp_rx_update(conn, pkt, len); case PKT_NOTIFICATION: return bgp_rx_notification(conn, pkt, len); case PKT_KEEPALIVE: return bgp_rx_keepalive(conn); case PKT_ROUTE_REFRESH: return bgp_rx_route_refresh(conn, pkt, len); default: bgp_error(conn, 1, 3, pkt+18, 1); } } /** * bgp_rx - handle received data * @sk: socket * @size: amount of data received * * bgp_rx() is called by the socket layer whenever new data arrive from * the underlying TCP connection. It assembles the data fragments to packets, * checks their headers and framing and passes complete packets to * bgp_rx_packet(). */ int bgp_rx(sock *sk, uint size) { struct bgp_conn *conn = sk->data; byte *pkt_start = sk->rbuf; byte *end = pkt_start + size; uint i, len; DBG("BGP: RX hook: Got %d bytes\n", size); while (end >= pkt_start + BGP_HEADER_LENGTH) { if ((conn->state == BS_CLOSE) || (conn->sk != sk)) return 0; for(i=0; i<16; i++) if (pkt_start[i] != 0xff) { bgp_error(conn, 1, 1, NULL, 0); break; } len = get_u16(pkt_start+16); if ((len < BGP_HEADER_LENGTH) || (len > bgp_max_packet_length(conn))) { bgp_error(conn, 1, 2, pkt_start+16, 2); break; } if (end < pkt_start + len) break; bgp_rx_packet(conn, pkt_start, len); pkt_start += len; } if (pkt_start != sk->rbuf) { memmove(sk->rbuf, pkt_start, end - pkt_start); sk->rpos = sk->rbuf + (end - pkt_start); } return 0; }