/* * 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 "nest/mrtdump.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 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]; } /* * MRT Dump format is not semantically specified. * We will use these values in appropriate fields: * * Local AS, Remote AS - configured AS numbers for given BGP instance. * Local IP, Remote IP - IP addresses of the TCP connection (0 if no connection) * * We dump two kinds of MRT messages: STATE_CHANGE (for BGP state * changes) and MESSAGE (for received BGP messages). * * STATE_CHANGE uses always AS4 variant, but MESSAGE uses AS4 variant * only when AS4 session is established and even in that case MESSAGE * does not use AS4 variant for initial OPEN message. This strange * behavior is here for compatibility with Quagga and Bgpdump, */ static byte * mrt_put_bgp4_hdr(byte *buf, struct bgp_conn *conn, int as4) { struct bgp_proto *p = conn->bgp; uint v4 = ipa_is_ip4(p->cf->remote_ip); if (as4) { put_u32(buf+0, p->remote_as); put_u32(buf+4, p->public_as); buf+=8; } else { put_u16(buf+0, (p->remote_as <= 0xFFFF) ? p->remote_as : AS_TRANS); put_u16(buf+2, (p->public_as <= 0xFFFF) ? p->public_as : AS_TRANS); buf+=4; } put_u16(buf+0, (p->neigh && p->neigh->iface) ? p->neigh->iface->index : 0); put_u16(buf+2, v4 ? BGP_AFI_IPV4 : BGP_AFI_IPV6); buf+=4; if (v4) { buf = put_ip4(buf, conn->sk ? ipa_to_ip4(conn->sk->daddr) : IP4_NONE); buf = put_ip4(buf, conn->sk ? ipa_to_ip4(conn->sk->saddr) : IP4_NONE); } else { buf = put_ip6(buf, conn->sk ? ipa_to_ip6(conn->sk->daddr) : IP6_NONE); buf = put_ip6(buf, conn->sk ? ipa_to_ip6(conn->sk->saddr) : IP6_NONE); } return buf; } static void mrt_dump_bgp_packet(struct bgp_conn *conn, byte *pkt, uint len) { byte *buf = alloca(128+len); /* 128 is enough for MRT headers */ byte *bp = buf + MRTDUMP_HDR_LENGTH; int as4 = conn->bgp->as4_session; bp = mrt_put_bgp4_hdr(bp, conn, as4); memcpy(bp, pkt, len); bp += len; mrt_dump_message(&conn->bgp->p, BGP4MP, as4 ? BGP4MP_MESSAGE_AS4 : BGP4MP_MESSAGE, buf, bp-buf); } static inline u16 convert_state(uint state) { /* Convert state from our BS_* values to values used in MRTDump */ return (state == BS_CLOSE) ? 1 : state + 1; } void mrt_dump_bgp_state_change(struct bgp_conn *conn, uint old, uint new) { byte buf[128]; byte *bp = buf + MRTDUMP_HDR_LENGTH; bp = mrt_put_bgp4_hdr(bp, conn, 1); put_u16(bp+0, convert_state(old)); put_u16(bp+2, convert_state(new)); bp += 4; mrt_dump_message(&conn->bgp->p, BGP4MP, BGP4MP_STATE_CHANGE_AS4, buf, bp-buf); } 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 *caps, u32 afi) { struct bgp_af_caps *ac; WALK_AF_CAPS(caps, ac) if (ac->afi == afi) return ac; 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; } static byte * bgp_write_capabilities(struct bgp_conn *conn, byte *buf) { struct bgp_proto *p = conn->bgp; struct bgp_channel *c; struct bgp_caps *caps; struct bgp_af_caps *ac; uint any_add_path = 0; byte *data; /* 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; 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; } /* Allocate and fill per-AF fields */ WALK_LIST(c, p->p.channels) { ac = &caps->af_data[caps->af_count++]; ac->afi = c->afi; ac->ready = 1; ac->add_path = c->cf->add_path; 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; } } /* Sort capability fields by AFI/SAFI */ qsort(caps->af_data, caps->af_count, sizeof(struct bgp_af_caps), bgp_af_caps_cmp); /* Create capability list in buffer */ /* * Note that max length is ~ 20+14*af_count. With max 6 channels that is * 104. Option limit is 253 and buffer size is 4096, so we cannot overflow * unless we add new capabilities or more AFs. */ 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->ext_messages) { *buf++ = 6; /* Capability 6: Support for extended messages */ *buf++ = 0; /* Capability data length */ } 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 (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 */ } return buf; } static void bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, int len) { struct bgp_proto *p = conn->bgp; struct bgp_af_caps *ac; int i, cl; u32 af; 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 6: /* Extended message length capability, RFC draft */ if (cl != 0) goto err; caps->ext_messages = 1; 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 4893 */ 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; /* We can safely ignore all other capabilities */ } ADVANCE(pos, len, 2 + cl); } return; err: bgp_error(conn, 2, 0, NULL, 0); return; } static int bgp_read_options(struct bgp_conn *conn, byte *pos, int len) { struct bgp_proto *p = conn->bgp; struct bgp_caps *caps; int ol; /* Max number of announced AFIs is limited by max option length (255) */ caps = alloca(sizeof(struct bgp_caps) + 64 * sizeof(struct bgp_af_caps)); memset(caps, 0, sizeof(struct bgp_caps)); while (len > 0) { if ((len < 2) || (len < (2 + pos[1]))) { bgp_error(conn, 2, 0, NULL, 0); return -1; } ol = pos[1]; if (pos[0] == 2) { /* BGP capabilities, RFC 5492 */ if (p->cf->capabilities) bgp_read_capabilities(conn, caps, pos + 2, ol); } else { /* Unknown option */ bgp_error(conn, 2, 4, pos, ol); /* FIXME: ol or ol+2 ? */ return -1; } ADVANCE(pos, len, 2 + ol); } uint n = sizeof(struct bgp_caps) + caps->af_count * sizeof(struct bgp_af_caps); conn->remote_caps = mb_allocz(p->p.pool, n); memcpy(conn->remote_caps, caps, n); return 0; } 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 *end = bgp_write_capabilities(conn, buf+12); uint len = end - (buf+12); buf[9] = len + 2; /* Optional parameters length */ buf[10] = 2; /* Option 2: Capability list */ buf[11] = len; /* Option data length */ return end; } else { /* Prepare empty local_caps */ conn->local_caps = mb_allocz(p->p.pool, sizeof(struct bgp_caps)); 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 contents */ if (len < 29 || len != 29 + (uint) pkt[28]) { 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]) < 0) return; if (hold > 0 && hold < 3) { 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; } 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); if (as4 != p->remote_as) { as4 = htonl(as4); bgp_error(conn, 2, 2, (byte *) &as4, 4); return; } } else { if (asn != p->remote_as) { bgp_error(conn, 2, 2, pkt+20, 2); 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 = MIN(hold, p->cf->hold_time); conn->keepalive_time = p->cf->keepalive_time ? : conn->hold_time / 3; 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 WITHDRAW(msg, args...) \ ({ REPORT(msg, ## args); s->err_withdraw = 1; return; }) #define BAD_NEXT_HOP "Invalid NEXT_HOP attribute" #define NO_NEXT_HOP "Missing NEXT_HOP attribute" 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_nonzero(gw)) nbr = neigh_find2(&p->p, &gw, NULL, 0); else if (ipa_nonzero(ll)) nbr = neigh_find2(&p->p, &ll, p->neigh->iface, 0); if (!nbr || (nbr->scope == SCOPE_HOST)) WITHDRAW(BAD_NEXT_HOP); a->dest = RTD_ROUTER; a->gw = nbr->addr; a->iface = nbr->iface; a->hostentry = NULL; a->igp_metric = 0; } else /* GW_RECURSIVE */ { if (ipa_zero(gw)) WITHDRAW(BAD_NEXT_HOP); rta_set_recursive_next_hop(c->c.table, a, c->igp_table, gw, ll); } } static inline int bgp_use_next_hop(struct bgp_export_state *s, eattr *a) { struct bgp_proto *p = s->proto; ip_addr *nh = (void *) a->u.ptr->data; if (s->channel->cf->next_hop_self) return 0; if (s->channel->cf->next_hop_keep) return 1; /* Keep it when explicitly set in export filter */ if (a->type & EAF_FRESH) return 1; /* 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->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; rta *ra = s->route->attrs; if (s->channel->cf->next_hop_self) return 0; /* We need valid global gateway */ if ((ra->dest != RTD_ROUTER) || ipa_zero(ra->gw) || ipa_is_link_local(ra->gw)) 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->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)) { ip_addr nh[1] = { s->route->attrs->gw }; bgp_set_attr_data(to, s->pool, BA_NEXT_HOP, 0, nh, 16); } 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); } } /* Check if next hop is valid */ a = bgp_find_attr(*to, BA_NEXT_HOP); if (!a) WITHDRAW(NO_NEXT_HOP); ip_addr *nh = (void *) a->u.ptr->data; ip_addr peer = s->proto->cf->remote_ip; uint len = a->u.ptr->length; if (ipa_zero(nh[0]) && ((len != 32) || ipa_zero(nh[1]))) WITHDRAW(BAD_NEXT_HOP); if (ipa_equal(peer, nh[0]) || ((len == 32) && ipa_equal(peer, nh[1]))) WITHDRAW(BAD_NEXT_HOP); } static uint bgp_encode_next_hop_none(struct bgp_write_state *s UNUSED, eattr *a UNUSED, byte *buf UNUSED, uint size UNUSED) { // FIXME return 0; } static void bgp_decode_next_hop_none(struct bgp_parse_state *s UNUSED, byte *data UNUSED, uint len UNUSED, rta *a UNUSED) { // FIXME return; } static void bgp_update_next_hop_none(struct bgp_export_state *s UNUSED, eattr *a UNUSED, ea_list **to UNUSED) { // FIXME } /* * UPDATE */ static void bgp_rte_update(struct bgp_parse_state *s, 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 withdraw */ rte_update2(&s->channel->c, n, NULL, s->last_src); return; } /* Prepare cached route attributes */ if (s->cached_rta == NULL) { a0->src = s->last_src; /* 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); e->pflags = 0; e->u.bgp.suppressed = 0; rte_update2(&s->channel->c, n, e, s->last_src); } 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 >= (5 + sizeof(ip4_addr)))) { 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); } ip4_addr a = ip4_hton(net->prefix); uint b = (net->pxlen + 7) / 8; /* Encode prefix length */ *pos = net->pxlen; ADVANCE(pos, size, 1); /* Encode prefix body */ 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; uint b = (l + 7) / 8; ADVANCE(pos, len, 1); if (l > IP4_MAX_PREFIX_LENGTH) bgp_parse_error(s, 10); if (len < b) bgp_parse_error(s, 1); /* Decode prefix body */ ip4_addr addr = IP4_NONE; 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_next_hop_ip4(struct bgp_write_state *s UNUSED, eattr *a, byte *buf, uint size UNUSED) { /* This function is used only for MP-BGP, see bgp_encode_next_hop() for IPv4 BGP */ ASSERT(a->u.ptr->length == sizeof(ip_addr)); put_ip4(buf, ipa_to_ip4( *(ip_addr *) a->u.ptr->data )); return 4; } static void bgp_decode_next_hop_ip4(struct bgp_parse_state *s, byte *data, uint len, rta *a) { if (len != 4) bgp_parse_error(s, 9); ip_addr nh = ipa_from_ip4(get_ip4(data)); // XXXX validate next hop bgp_set_attr_data(&(a->eattrs), s->pool, BA_NEXT_HOP, 0, &nh, sizeof(nh)); bgp_apply_next_hop(s, a, nh, IPA_NONE); } 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 >= (5 + sizeof(ip6_addr)))) { 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); } ip6_addr a = ip6_hton(net->prefix); uint b = (net->pxlen + 7) / 8; /* Encode prefix length */ *pos = net->pxlen; ADVANCE(pos, size, 1); /* Encode prefix body */ 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; uint b = (l + 7) / 8; ADVANCE(pos, len, 1); if (l > IP6_MAX_PREFIX_LENGTH) bgp_parse_error(s, 10); if (len < b) bgp_parse_error(s, 1); /* Decode prefix body */ ip6_addr addr = IP6_NONE; 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_next_hop_ip6(struct bgp_write_state *s UNUSED, 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)); 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_ip6(struct bgp_parse_state *s, byte *data, uint len, rta *a) { struct adata *ad = lp_alloc_adata(s->pool, 32); ip_addr *nh = (void *) ad->data; if ((len != 16) && (len != 32)) bgp_parse_error(s, 9); nh[0] = ipa_from_ip6(get_ip6(data)); nh[1] = (len == 32) ? ipa_from_ip6(get_ip6(data+16)) : IPA_NONE; if (ip6_is_link_local(nh[0])) { nh[1] = nh[0]; nh[0] = IPA_NONE; } if (!ip6_is_link_local(nh[1])) nh[1] = IPA_NONE; if (ipa_zero(nh[1])) ad->length = 16; // 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_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); } if (data[0] != FLOW_TYPE_DST_PREFIX) { log(L_REMOTE "%s: No dst prefix at first pos", s->proto->p.name); bgp_parse_error(s, 1); } /* Decode dst prefix */ ip4_addr px = IP4_NONE; uint pxlen = data[1]; // FIXME: Use some generic function memcpy(&px, data, BYTES(pxlen)); px = ip4_and(px, ip4_mkmask(pxlen)); /* 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); 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); } if (data[0] != FLOW_TYPE_DST_PREFIX) { log(L_REMOTE "%s: No dst prefix at first pos", s->proto->p.name); bgp_parse_error(s, 1); } /* Decode dst prefix */ ip6_addr px = IP6_NONE; uint pxlen = data[1]; // FIXME: Use some generic function memcpy(&px, data, BYTES(pxlen)); px = ip6_and(px, ip6_mkmask(pxlen)); /* 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); 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_ip4, .decode_next_hop = bgp_decode_next_hop_ip4, .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_ip4, .decode_next_hop = bgp_decode_next_hop_ip4, .update_next_hop = bgp_update_next_hop_ip, }, { .afi = BGP_AF_FLOW4, .net = NET_FLOW4, .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_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_ip6, .decode_next_hop = bgp_decode_next_hop_ip6, .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_ip6, .decode_next_hop = bgp_decode_next_hop_ip6, .update_next_hop = bgp_update_next_hop_ip, }, { .afi = BGP_AF_FLOW6, .net = NET_FLOW6, .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; /* Initialize write state */ struct bgp_write_state s = { .proto = p, .channel = c, .pool = bgp_linpool, .as4_session = p->as4_session, .add_path = c->add_path_tx, }; again: /* Try unreachable bucket */ if ((buck = c->withdraw_bucket) && !EMPTY_LIST(buck->prefixes)) { res = (c->afi == BGP_AF_IPV4) ? 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); goto again; } res = (c->afi == BGP_AF_IPV4) ? 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) goto again; goto done; } /* No more prefixes to send */ return NULL; done: BGP_TRACE_RL(&rl_snd_update, D_PACKETS, "Sending UPDATE"); lp_flush(s.pool); 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"); 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_proto *p, u32 afi) { struct bgp_channel *c = bgp_get_channel(p, afi); BGP_TRACE(D_PACKETS, "Got END-OF-RIB"); /* XXXX handle unknown AF in MP_*_NLRI */ if (!c) return; 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; /* XXXX handle unknown AF in MP_*_NLRI */ if (!c) return; s->channel = c; s->add_path = c->add_path_rx; 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 = alloca(sizeof(struct rta)); memset(a, 0, sizeof(struct rta)); a->source = RTS_BGP; a->scope = SCOPE_UNIVERSE; a->cast = RTC_UNICAST; a->dest = RTD_UNREACHABLE; a->from = s->proto->cf->remote_ip; a->eattrs = ea; c->desc->decode_next_hop(s, nh, nh_len, 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"); /* 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); /* Initialize parse state */ struct bgp_parse_state s = { .proto = p, .pool = bgp_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); /* Check for End-of-RIB marker */ if (!s.attr_len && !s.ip_unreach_len && !s.ip_reach_len) { bgp_rx_end_mark(p, 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) /* XXXX See RFC 7606 5.2 */ { bgp_rx_end_mark(p, 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); 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_flush(s.pool); return; } /* * 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; 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_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 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 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"); while (bgp_fire_tx(conn) > 0) ; } void bgp_tx(sock *sk) { struct bgp_conn *conn = sk->data; DBG("BGP: TX hook\n"); while (bgp_fire_tx(conn) > 0) ; } 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 */ { 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; } void bgp_log_error(struct bgp_proto *p, u8 class, char *msg, uint code, uint subcode, byte *data, uint len) { const byte *name; byte *t, argbuf[36]; uint i; /* Don't report Cease messages generated by myself */ if (code == 6 && class == BE_BGP_TX) return; name = bgp_error_dsc(code, subcode); t = argbuf; if (len) { *t++ = ':'; *t++ = ' '; if ((code == 2) && (subcode == 2) && ((len == 2) || (len == 4))) { /* Bad peer AS - we would like to print the AS */ t += bsprintf(t, "%u", (len == 2) ? get_u16(data) : get_u32(data)); goto done; } if (len > 16) len = 16; for (i=0; ip.name, msg, name, 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); } } 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); if (conn->bgp->p.mrtdump & MD_MESSAGES) mrt_dump_bgp_packet(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; }