/* * EIGRP Sending and Receiving EIGRP Hello Packets. * Copyright (C) 2013-2016 * Authors: * Donnie Savage * Jan Janovic * Matej Perina * Peter Orsag * Peter Paluch * Frantisek Gazo * Tomas Hvorkovy * Martin Kontsek * Lukas Koribsky * * This file is part of GNU Zebra. * * GNU Zebra is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2, or (at your option) any * later version. * * GNU Zebra is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; see the file COPYING; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include #include "thread.h" #include "memory.h" #include "linklist.h" #include "prefix.h" #include "if.h" #include "table.h" #include "sockunion.h" #include "stream.h" #include "log.h" #include "sockopt.h" #include "checksum.h" #include "vty.h" #include "md5.h" #include "eigrpd/eigrp_structs.h" #include "eigrpd/eigrpd.h" #include "eigrpd/eigrp_interface.h" #include "eigrpd/eigrp_neighbor.h" #include "eigrpd/eigrp_packet.h" #include "eigrpd/eigrp_zebra.h" #include "eigrpd/eigrp_vty.h" #include "eigrpd/eigrp_dump.h" #include "eigrpd/eigrp_macros.h" #include "eigrpd/eigrp_errors.h" /* Packet Type String. */ static const struct message eigrp_general_tlv_type_str[] = { {EIGRP_TLV_PARAMETER, "PARAMETER"}, {EIGRP_TLV_AUTH, "AUTH"}, {EIGRP_TLV_SEQ, "SEQ"}, {EIGRP_TLV_SW_VERSION, "SW_VERSION"}, {EIGRP_TLV_NEXT_MCAST_SEQ, "NEXT_MCAST_SEQ"}, {EIGRP_TLV_PEER_TERMINATION, "PEER_TERMINATION"}, {EIGRP_TLV_PEER_MTRLIST, "PEER_MTRLIST"}, {EIGRP_TLV_PEER_TIDLIST, "PEER_TIDLIST"}, {0}}; /* * @fn eigrp_hello_timer * * @param[in] thread current execution thread timer is associated with * * @return int always returns 0 * * @par * Called once per "hello" time interval, default 5 seconds * Sends hello packet via multicast for all interfaces eigrp * is configured for */ int eigrp_hello_timer(struct thread *thread) { struct eigrp_interface *ei; ei = THREAD_ARG(thread); if (IS_DEBUG_EIGRP(0, TIMERS)) zlog_debug("Start Hello Timer (%s) Expire [%u]", IF_NAME(ei), ei->params.v_hello); /* Sending hello packet. */ eigrp_hello_send(ei, EIGRP_HELLO_NORMAL, NULL); /* Hello timer set. */ thread_add_timer(master, eigrp_hello_timer, ei, ei->params.v_hello, &ei->t_hello); return 0; } /** * @fn eigrp_hello_parameter_decode * * @param[in] nbr neighbor the ACK should be sent to * @param[in] param pointer packet TLV is stored to * * @return uint16_t number of bytes added to packet stream * * @par * Encode Parameter TLV, used to convey metric weights and the hold time. * * @usage * Note the addition of K6 for the new extended metrics, and does not apply to * older TLV packet formats. */ static struct eigrp_neighbor * eigrp_hello_parameter_decode(struct eigrp_neighbor *nbr, struct eigrp_tlv_hdr_type *tlv) { struct eigrp *eigrp = nbr->ei->eigrp; struct TLV_Parameter_Type *param = (struct TLV_Parameter_Type *)tlv; /* First validate TLV length */ if (tlv->length < sizeof(struct TLV_Parameter_Type)) return NULL; /* copy over the values passed in by the neighbor */ nbr->K1 = param->K1; nbr->K2 = param->K2; nbr->K3 = param->K3; nbr->K4 = param->K4; nbr->K5 = param->K5; nbr->K6 = param->K6; nbr->v_holddown = ntohs(param->hold_time); /* * Check K1-K5 have the correct values to be able to become neighbors * K6 does not have to match */ if ((eigrp->k_values[0] == nbr->K1) && (eigrp->k_values[1] == nbr->K2) && (eigrp->k_values[2] == nbr->K3) && (eigrp->k_values[3] == nbr->K4) && (eigrp->k_values[4] == nbr->K5)) { if (eigrp_nbr_state_get(nbr) == EIGRP_NEIGHBOR_DOWN) { zlog_info( "Neighbor %pI4 (%s) is pending: new adjacency", &nbr->src, ifindex2ifname(nbr->ei->ifp->ifindex, eigrp->vrf_id)); /* Expedited hello sent */ eigrp_hello_send(nbr->ei, EIGRP_HELLO_NORMAL, NULL); // if(ntohl(nbr->ei->address->u.prefix4.s_addr) > // ntohl(nbr->src.s_addr)) eigrp_update_send_init(nbr); eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_PENDING); } } else { if (eigrp_nbr_state_get(nbr) != EIGRP_NEIGHBOR_DOWN) { if ((param->K1 & param->K2 & param->K3 & param->K4 & param->K5) == 255) { zlog_info( "Neighbor %pI4 (%s) is down: Interface PEER-TERMINATION received", &nbr->src, ifindex2ifname(nbr->ei->ifp->ifindex, eigrp->vrf_id)); eigrp_nbr_delete(nbr); return NULL; } else { zlog_info( "Neighbor %pI4 (%s) going down: Kvalue mismatch", &nbr->src, ifindex2ifname(nbr->ei->ifp->ifindex, eigrp->vrf_id)); eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_DOWN); } } } return nbr; } static uint8_t eigrp_hello_authentication_decode(struct stream *s, struct eigrp_tlv_hdr_type *tlv_header, struct eigrp_neighbor *nbr) { struct TLV_MD5_Authentication_Type *md5; md5 = (struct TLV_MD5_Authentication_Type *)tlv_header; if (md5->auth_type == EIGRP_AUTH_TYPE_MD5) { /* Validate tlv length */ if (md5->length < sizeof(struct TLV_MD5_Authentication_Type)) return 0; return eigrp_check_md5_digest(s, md5, nbr, EIGRP_AUTH_BASIC_HELLO_FLAG); } else if (md5->auth_type == EIGRP_AUTH_TYPE_SHA256) { /* Validate tlv length */ if (md5->length < sizeof(struct TLV_SHA256_Authentication_Type)) return 0; return eigrp_check_sha256_digest( s, (struct TLV_SHA256_Authentication_Type *)tlv_header, nbr, EIGRP_AUTH_BASIC_HELLO_FLAG); } return 0; } /** * @fn eigrp_sw_version_decode * * @param[in] nbr neighbor the ACK shoudl be sent to * @param[in] param pointer to TLV software version information * * @return void * * @par * Read the software version in the specified location. * This consists of two bytes of OS version, and two bytes of EIGRP * revision number. */ static void eigrp_sw_version_decode(struct eigrp_neighbor *nbr, struct eigrp_tlv_hdr_type *tlv) { struct TLV_Software_Type *version = (struct TLV_Software_Type *)tlv; /* Validate TLV length */ if (tlv->length < sizeof(struct TLV_Software_Type)) return; nbr->os_rel_major = version->vender_major; nbr->os_rel_minor = version->vender_minor; nbr->tlv_rel_major = version->eigrp_major; nbr->tlv_rel_minor = version->eigrp_minor; return; } /** * @fn eigrp_peer_termination_decode * * @param[in] nbr neighbor the ACK shoudl be sent to * @param[in] tlv pointer to TLV software version information * * @return void * * @par * Read the address in the TLV and match to out address. If * a match is found, move the sending neighbor to the down state. If * out address is not in the TLV, then ignore the peer termination */ static void eigrp_peer_termination_decode(struct eigrp_neighbor *nbr, struct eigrp_tlv_hdr_type *tlv) { struct eigrp *eigrp = nbr->ei->eigrp; struct TLV_Peer_Termination_type *param = (struct TLV_Peer_Termination_type *)tlv; /* Validate TLV length */ if (tlv->length < sizeof(struct TLV_Peer_Termination_type)) return; uint32_t my_ip = nbr->ei->address.u.prefix4.s_addr; uint32_t received_ip = param->neighbor_ip; if (my_ip == received_ip) { zlog_info( "Neighbor %pI4 (%s) is down: Peer Termination received", &nbr->src, ifindex2ifname(nbr->ei->ifp->ifindex, eigrp->vrf_id)); /* set neighbor to DOWN */ nbr->state = EIGRP_NEIGHBOR_DOWN; /* delete neighbor */ eigrp_nbr_delete(nbr); } } /** * @fn eigrp_peer_termination_encode * * @param[in,out] s packet stream TLV is stored to * @param[in] nbr_addr pointer to neighbor address for Peer * Termination TLV * * @return uint16_t number of bytes added to packet stream * * @par * Function used to encode Peer Termination TLV to Hello packet. */ static uint16_t eigrp_peer_termination_encode(struct stream *s, struct in_addr *nbr_addr) { uint16_t length = EIGRP_TLV_PEER_TERMINATION_LEN; /* fill in type and length */ stream_putw(s, EIGRP_TLV_PEER_TERMINATION); stream_putw(s, length); /* fill in unknown field 0x04 */ stream_putc(s, 0x04); /* finally neighbor IP address */ stream_put_ipv4(s, nbr_addr->s_addr); return (length); } /* * @fn eigrp_hello_receive * * @param[in] eigrp eigrp routing process * @param[in] iph pointer to ip header * @param[in] eigrph pointer to eigrp header * @param[in] s input ip stream * @param[in] ei eigrp interface packet arrived on * @param[in] size size of eigrp packet * * @return void * * @par * This is the main worker function for processing hello packets. It * will validate the peer associated with the src ip address of the ip * header, and then decode each of the general TLVs which the packet * may contain. * * @usage * Not all TLVs are current decoder. This is a work in progress.. */ void eigrp_hello_receive(struct eigrp *eigrp, struct ip *iph, struct eigrp_header *eigrph, struct stream *s, struct eigrp_interface *ei, int size) { struct eigrp_tlv_hdr_type *tlv_header; struct eigrp_neighbor *nbr; uint16_t type; uint16_t length; /* get neighbor struct */ nbr = eigrp_nbr_get(ei, eigrph, iph); /* neighbor must be valid, eigrp_nbr_get creates if none existed */ assert(nbr); if (IS_DEBUG_EIGRP_PACKET(eigrph->opcode - 1, RECV)) zlog_debug("Processing Hello size[%u] int(%s) nbr(%pI4)", size, ifindex2ifname(nbr->ei->ifp->ifindex, eigrp->vrf_id), &nbr->src); size -= EIGRP_HEADER_LEN; if (size < 0) return; tlv_header = (struct eigrp_tlv_hdr_type *)eigrph->tlv; do { type = ntohs(tlv_header->type); length = ntohs(tlv_header->length); /* Validate length against packet size */ if (length > size) return; if ((length > 0) && (length <= size)) { if (IS_DEBUG_EIGRP_PACKET(0, RECV)) zlog_debug( " General TLV(%s)", lookup_msg(eigrp_general_tlv_type_str, type, NULL)); // determine what General TLV is being processed switch (type) { case EIGRP_TLV_PARAMETER: nbr = eigrp_hello_parameter_decode(nbr, tlv_header); if (!nbr) return; break; case EIGRP_TLV_AUTH: { if (eigrp_hello_authentication_decode( s, tlv_header, nbr) == 0) return; else break; break; } case EIGRP_TLV_SEQ: break; case EIGRP_TLV_SW_VERSION: eigrp_sw_version_decode(nbr, tlv_header); break; case EIGRP_TLV_NEXT_MCAST_SEQ: break; case EIGRP_TLV_PEER_TERMINATION: eigrp_peer_termination_decode(nbr, tlv_header); return; break; case EIGRP_TLV_PEER_MTRLIST: case EIGRP_TLV_PEER_TIDLIST: break; default: break; } } tlv_header = (struct eigrp_tlv_hdr_type *)(((char *)tlv_header) + length); size -= length; } while (size > 0); /*If received packet is hello with Parameter TLV*/ if (ntohl(eigrph->ack) == 0) { /* increment statistics. */ ei->hello_in++; if (nbr) eigrp_nbr_state_update(nbr); } if (IS_DEBUG_EIGRP_PACKET(0, RECV)) zlog_debug("Hello Packet received from %pI4", &nbr->src); } uint32_t FRR_MAJOR; uint32_t FRR_MINOR; void eigrp_sw_version_initialize(void) { char ver_string[] = VERSION; char *dash = strstr(ver_string, "-"); int ret; if (dash) dash[0] = '\0'; ret = sscanf(ver_string, "%" SCNu32 ".%" SCNu32, &FRR_MAJOR, &FRR_MINOR); if (ret != 2) flog_err(EC_EIGRP_PACKET, "Did not Properly parse %s, please fix VERSION string", VERSION); } /** * @fn eigrp_sw_version_encode * * @param[in,out] s packet stream TLV is stored to * * @return uint16_t number of bytes added to packet stream * * @par * Store the software version in the specified location. * This consists of two bytes of OS version, and two bytes of EIGRP * revision number. */ static uint16_t eigrp_sw_version_encode(struct stream *s) { uint16_t length = EIGRP_TLV_SW_VERSION_LEN; // setup the tlv fields stream_putw(s, EIGRP_TLV_SW_VERSION); stream_putw(s, length); stream_putc(s, FRR_MAJOR); //!< major os version stream_putc(s, FRR_MINOR); //!< minor os version /* and the core eigrp version */ stream_putc(s, EIGRP_MAJOR_VERSION); stream_putc(s, EIGRP_MINOR_VERSION); return (length); } /** * @fn eigrp_tidlist_encode * * @param[in,out] s packet stream TLV is stored to * * @return void * * @par * If doing mutli-topology, then store the supported TID list. * This is currently a place holder function */ static uint16_t eigrp_tidlist_encode(struct stream *s) { // uint16_t length = EIGRP_TLV_SW_VERSION_LEN; return 0; } /** * @fn eigrp_sequence_encode * * @param[in,out] s packet stream TLV is stored to * * @return uint16_t number of bytes added to packet stream * * @par * Part of conditional receive process * */ static uint16_t eigrp_sequence_encode(struct eigrp *eigrp, struct stream *s) { uint16_t length = EIGRP_TLV_SEQ_BASE_LEN; struct eigrp_interface *ei; struct listnode *node, *node2, *nnode2; struct eigrp_neighbor *nbr; size_t backup_end, size_end; int found; // add in the parameters TLV backup_end = stream_get_endp(s); stream_putw(s, EIGRP_TLV_SEQ); size_end = s->endp; stream_putw(s, 0x0000); stream_putc(s, IPV4_MAX_BYTELEN); found = 0; for (ALL_LIST_ELEMENTS_RO(eigrp->eiflist, node, ei)) { for (ALL_LIST_ELEMENTS(ei->nbrs, node2, nnode2, nbr)) { if (nbr->multicast_queue->count > 0) { length += (uint16_t)stream_put_ipv4( s, nbr->src.s_addr); found = 1; } } } if (found == 0) { stream_set_endp(s, backup_end); return 0; } backup_end = stream_get_endp(s); stream_set_endp(s, size_end); stream_putw(s, length); stream_set_endp(s, backup_end); return length; } /** * @fn eigrp_sequence_encode * * @param[in,out] s packet stream TLV is stored to * * @return uint16_t number of bytes added to packet stream * * @par * Part of conditional receive process * */ static uint16_t eigrp_next_sequence_encode(struct eigrp *eigrp, struct stream *s) { uint16_t length = EIGRP_NEXT_SEQUENCE_TLV_SIZE; // add in the parameters TLV stream_putw(s, EIGRP_TLV_NEXT_MCAST_SEQ); stream_putw(s, EIGRP_NEXT_SEQUENCE_TLV_SIZE); stream_putl(s, eigrp->sequence_number + 1); return length; } /** * @fn eigrp_hello_parameter_encode * * @param[in] ei pointer to interface hello packet came in on * @param[in,out] s packet stream TLV is stored to * * @return uint16_t number of bytes added to packet stream * * @par * Encode Parameter TLV, used to convey metric weights and the hold time. * * @usage * Note the addition of K6 for the new extended metrics, and does not apply to * older TLV packet formats. */ static uint16_t eigrp_hello_parameter_encode(struct eigrp_interface *ei, struct stream *s, uint8_t flags) { // add in the parameters TLV stream_putw(s, EIGRP_TLV_PARAMETER); stream_putw(s, EIGRP_TLV_PARAMETER_LEN); // if graceful shutdown is needed to be announced, send all 255 in K // values if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) { stream_putc(s, 0xff); /* K1 */ stream_putc(s, 0xff); /* K2 */ stream_putc(s, 0xff); /* K3 */ stream_putc(s, 0xff); /* K4 */ stream_putc(s, 0xff); /* K5 */ stream_putc(s, 0xff); /* K6 */ } else // set k values { stream_putc(s, ei->eigrp->k_values[0]); /* K1 */ stream_putc(s, ei->eigrp->k_values[1]); /* K2 */ stream_putc(s, ei->eigrp->k_values[2]); /* K3 */ stream_putc(s, ei->eigrp->k_values[3]); /* K4 */ stream_putc(s, ei->eigrp->k_values[4]); /* K5 */ stream_putc(s, ei->eigrp->k_values[5]); /* K6 */ } // and set hold time value.. stream_putw(s, ei->params.v_wait); return EIGRP_TLV_PARAMETER_LEN; } /** * @fn eigrp_hello_encode * * @param[in] ei pointer to interface hello packet came in on * @param[in] s packet stream TLV is stored to * @param[in] ack if non-zero, neigbors sequence packet to ack * @param[in] flags type of hello packet * @param[in] nbr_addr pointer to neighbor address for Peer * Termination TLV * * @return eigrp_packet pointer initialize hello packet * * @par * Allocate an EIGRP hello packet, and add in the the approperate TLVs * */ static struct eigrp_packet *eigrp_hello_encode(struct eigrp_interface *ei, in_addr_t addr, uint32_t ack, uint8_t flags, struct in_addr *nbr_addr) { struct eigrp_packet *ep; uint16_t length = EIGRP_HEADER_LEN; // allocate a new packet to be sent ep = eigrp_packet_new(EIGRP_PACKET_MTU(ei->ifp->mtu), NULL); if (ep) { // encode common header feilds eigrp_packet_header_init(EIGRP_OPC_HELLO, ei->eigrp, ep->s, 0, 0, ack); // encode Authentication TLV if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5) && (ei->params.auth_keychain != NULL)) { length += eigrp_add_authTLV_MD5_to_stream(ep->s, ei); } else if ((ei->params.auth_type == EIGRP_AUTH_TYPE_SHA256) && (ei->params.auth_keychain != NULL)) { length += eigrp_add_authTLV_SHA256_to_stream(ep->s, ei); } /* encode appropriate parameters to Hello packet */ if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) length += eigrp_hello_parameter_encode( ei, ep->s, EIGRP_HELLO_GRACEFUL_SHUTDOWN); else length += eigrp_hello_parameter_encode( ei, ep->s, EIGRP_HELLO_NORMAL); // figure out the version of code we're running length += eigrp_sw_version_encode(ep->s); if (flags & EIGRP_HELLO_ADD_SEQUENCE) { length += eigrp_sequence_encode(ei->eigrp, ep->s); length += eigrp_next_sequence_encode(ei->eigrp, ep->s); } // add in the TID list if doing multi-topology length += eigrp_tidlist_encode(ep->s); /* encode Peer Termination TLV if needed */ if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN_NBR) length += eigrp_peer_termination_encode(ep->s, nbr_addr); // Set packet length ep->length = length; // set soruce address for the hello packet ep->dst.s_addr = addr; if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5) && (ei->params.auth_keychain != NULL)) { eigrp_make_md5_digest(ei, ep->s, EIGRP_AUTH_BASIC_HELLO_FLAG); } else if ((ei->params.auth_type == EIGRP_AUTH_TYPE_SHA256) && (ei->params.auth_keychain != NULL)) { eigrp_make_sha256_digest(ei, ep->s, EIGRP_AUTH_BASIC_HELLO_FLAG); } // EIGRP Checksum eigrp_packet_checksum(ei, ep->s, length); } return (ep); } /** * @fn eigrp_hello_send * * @param[in] nbr neighbor the ACK should be sent to * * @return void * * @par * Send (unicast) a hello packet with the destination address * associated with the neighbor. The eigrp header ACK feild will be * updated to the neighbor's sequence number to acknolodge any * outstanding packets */ void eigrp_hello_send_ack(struct eigrp_neighbor *nbr) { struct eigrp_packet *ep; /* if packet succesfully created, add it to the interface queue */ ep = eigrp_hello_encode(nbr->ei, nbr->src.s_addr, nbr->recv_sequence_number, EIGRP_HELLO_NORMAL, NULL); if (ep) { if (IS_DEBUG_EIGRP_PACKET(0, SEND)) zlog_debug("Queueing [Hello] Ack Seq [%u] nbr [%pI4]", nbr->recv_sequence_number, &nbr->src); /* Add packet to the top of the interface output queue*/ eigrp_fifo_push(nbr->ei->obuf, ep); /* Hook thread to write packet. */ if (nbr->ei->on_write_q == 0) { listnode_add(nbr->ei->eigrp->oi_write_q, nbr->ei); nbr->ei->on_write_q = 1; } thread_add_write(master, eigrp_write, nbr->ei->eigrp, nbr->ei->eigrp->fd, &nbr->ei->eigrp->t_write); } } /** * @fn eigrp_hello_send * * @param[in] ei pointer to interface hello should be sent * @param[in] flags type of hello packet * @param[in] nbr_addr pointer to neighbor address for Peer * Termination TLV * * @return void * * @par * Build and enqueue a generic (multicast) periodic hello packet for * sending. If no packets are currently queues, the packet will be * sent immadiatly */ void eigrp_hello_send(struct eigrp_interface *ei, uint8_t flags, struct in_addr *nbr_addr) { struct eigrp_packet *ep = NULL; if (IS_DEBUG_EIGRP_PACKET(0, SEND)) zlog_debug("Queueing [Hello] Interface(%s)", IF_NAME(ei)); /* if packet was succesfully created, then add it to the interface queue */ ep = eigrp_hello_encode(ei, htonl(EIGRP_MULTICAST_ADDRESS), 0, flags, nbr_addr); if (ep) { // Add packet to the top of the interface output queue eigrp_fifo_push(ei->obuf, ep); /* Hook thread to write packet. */ if (ei->on_write_q == 0) { listnode_add(ei->eigrp->oi_write_q, ei); ei->on_write_q = 1; } if (ei->eigrp->t_write == NULL) { if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) { thread_execute(master, eigrp_write, ei->eigrp, ei->eigrp->fd); } else { thread_add_write(master, eigrp_write, ei->eigrp, ei->eigrp->fd, &ei->eigrp->t_write); } } } }