Adding upstream version 8.4.4.upstream/8.4.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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);
+			}
+		}
+	}
+}