summaryrefslogtreecommitdiffstats
path: root/eigrpd/eigrp_hello.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--eigrpd/eigrp_hello.c798
1 files changed, 798 insertions, 0 deletions
diff --git a/eigrpd/eigrp_hello.c b/eigrpd/eigrp_hello.c
new file mode 100644
index 0000000..717d8c0
--- /dev/null
+++ b/eigrpd/eigrp_hello.c
@@ -0,0 +1,798 @@
+/*
+ * 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 <zebra.h>
+
+#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 void
+ *
+ * @par
+ * Called once per "hello" time interval, default 5 seconds
+ * Sends hello packet via multicast for all interfaces eigrp
+ * is configured for
+ */
+void 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);
+}
+
+/**
+ * @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);
+ }
+ }
+ }
+}