diff --git a/lib/gro/gro_tcp.h b/lib/gro/gro_tcp.h
new file mode 100644
index 0000000000..d926c4b8cc
--- /dev/null
+++ b/lib/gro/gro_tcp.h
@@ -0,0 +1,190 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2023 Intel Corporation
+ */
+#ifndef _GRO_TCP_H_
+#define _GRO_TCP_H_
+
+#define INVALID_ARRAY_INDEX 0xffffffffUL
+
+#include <rte_tcp.h>
+
+/*
+ * The max length of a IPv4 packet, which includes the length of the L3
+ * header, the L4 header and the data payload.
+ */
+#define MAX_IP_PKT_LENGTH UINT16_MAX
+
+/* The maximum TCP header length */
+#define MAX_TCP_HLEN 60
+#define INVALID_TCP_HDRLEN(len) \
+	(((len) < sizeof(struct rte_tcp_hdr)) || ((len) > MAX_TCP_HLEN))
+
+struct cmn_tcp_key {
+	struct rte_ether_addr eth_saddr;
+	struct rte_ether_addr eth_daddr;
+	uint32_t recv_ack;
+	uint16_t src_port;
+	uint16_t dst_port;
+};
+
+#define ASSIGN_COMMON_TCP_KEY(k1, k2) \
+	do {\
+		rte_ether_addr_copy(&(k1->eth_saddr), &(k2->eth_saddr)); \
+		rte_ether_addr_copy(&(k1->eth_daddr), &(k2->eth_daddr)); \
+		k2->recv_ack = k1->recv_ack; \
+		k2->src_port = k1->src_port; \
+		k2->dst_port = k1->dst_port; \
+	} while (0)
+
+struct gro_tcp_item {
+	/*
+	 * The first MBUF segment of the packet. If the value
+	 * is NULL, it means the item is empty.
+	 */
+	struct rte_mbuf *firstseg;
+	/* The last MBUF segment of the packet */
+	struct rte_mbuf *lastseg;
+	/*
+	 * The time when the first packet is inserted into the table.
+	 * This value won't be updated, even if the packet is merged
+	 * with other packets.
+	 */
+	uint64_t start_time;
+	/*
+	 * next_pkt_idx is used to chain the packets that
+	 * are in the same flow but can't be merged together
+	 * (e.g. caused by packet reordering).
+	 */
+	uint32_t next_pkt_idx;
+	/* TCP sequence number of the packet */
+	uint32_t sent_seq;
+	union {
+		/* IPv4 ID of the packet */
+		uint16_t ip_id;
+		/* Unused field for IPv6 */
+		uint16_t unused;
+	} l3;
+	/* the number of merged packets */
+	uint16_t nb_merged;
+	/* Indicate if IPv4 ID can be ignored */
+	uint8_t is_atomic;
+};
+
+/*
+ * Merge two TCP packets without updating checksums.
+ * If cmp is larger than 0, append the new packet to the
+ * original packet. Otherwise, pre-pend the new packet to
+ * the original packet.
+ */
+static inline int
+merge_two_tcp_packets(struct gro_tcp_item *item,
+		struct rte_mbuf *pkt,
+		int cmp,
+		uint32_t sent_seq,
+		uint16_t ip_id,
+		uint16_t l2_offset)
+{
+	struct rte_mbuf *pkt_head, *pkt_tail, *lastseg;
+	uint16_t hdr_len, l2_len;
+
+	if (cmp > 0) {
+		pkt_head = item->firstseg;
+		pkt_tail = pkt;
+	} else {
+		pkt_head = pkt;
+		pkt_tail = item->firstseg;
+	}
+
+	/* check if the IPv4 packet length is greater than the max value */
+	hdr_len = l2_offset + pkt_head->l2_len + pkt_head->l3_len +
+		pkt_head->l4_len;
+	l2_len = l2_offset > 0 ? pkt_head->outer_l2_len : pkt_head->l2_len;
+	if (unlikely(pkt_head->pkt_len - l2_len + pkt_tail->pkt_len -
+				hdr_len > MAX_IP_PKT_LENGTH))
+		return 0;
+
+	if (unlikely(pkt_head->nb_segs >= 20))
+		return 0;
+
+	/* remove the packet header for the tail packet */
+	rte_pktmbuf_adj(pkt_tail, hdr_len);
+
+	/* chain two packets together */
+	if (cmp > 0) {
+		item->lastseg->next = pkt;
+		item->lastseg = rte_pktmbuf_lastseg(pkt);
+		/* update IP ID to the larger value */
+		item->l3.ip_id = ip_id;
+	} else {
+		lastseg = rte_pktmbuf_lastseg(pkt);
+		lastseg->next = item->firstseg;
+		item->firstseg = pkt;
+		/* update sent_seq to the smaller value */
+		item->sent_seq = sent_seq;
+		item->l3.ip_id = ip_id;
+	}
+	item->nb_merged++;
+
+	/* update MBUF metadata for the merged packet */
+	pkt_head->nb_segs += pkt_tail->nb_segs;
+	pkt_head->pkt_len += pkt_tail->pkt_len;
+
+	return 1;
+}
+
+/*
+ * Check if two TCP packets are neighbors.
+ */
+static inline int
+check_seq_option(struct gro_tcp_item *item,
+		struct rte_tcp_hdr *tcph,
+		uint32_t sent_seq,
+		uint16_t ip_id,
+		uint16_t tcp_hl,
+		uint16_t tcp_dl,
+		uint16_t l2_offset,
+		uint8_t is_atomic)
+{
+	struct rte_mbuf *pkt_orig = item->firstseg;
+	char *iph_orig;
+	struct rte_tcp_hdr *tcph_orig;
+	uint16_t len, tcp_hl_orig;
+
+	iph_orig = (char *)(rte_pktmbuf_mtod(pkt_orig, char *) +
+			l2_offset + pkt_orig->l2_len);
+	tcph_orig = (struct rte_tcp_hdr *)(iph_orig + pkt_orig->l3_len);
+	tcp_hl_orig = pkt_orig->l4_len;
+
+	/* Check if TCP option fields equal */
+	len = RTE_MAX(tcp_hl, tcp_hl_orig) - sizeof(struct rte_tcp_hdr);
+	if ((tcp_hl != tcp_hl_orig) || ((len > 0) &&
+				(memcmp(tcph + 1, tcph_orig + 1,
+					len) != 0)))
+		return 0;
+
+	/* Don't merge packets whose DF bits are different */
+	if (unlikely(item->is_atomic ^ is_atomic))
+		return 0;
+
+	/* check if the two packets are neighbors */
+	len = pkt_orig->pkt_len - l2_offset - pkt_orig->l2_len -
+		pkt_orig->l3_len - tcp_hl_orig;
+	if ((sent_seq == item->sent_seq + len) && (is_atomic ||
+				(ip_id == item->l3.ip_id + 1)))
+		/* append the new packet */
+		return 1;
+	else if ((sent_seq + tcp_dl == item->sent_seq) && (is_atomic ||
+				(ip_id + item->nb_merged == item->l3.ip_id)))
+		/* pre-pend the new packet */
+		return -1;
+
+	return 0;
+}
+
+static inline int
+is_same_common_tcp_key(struct cmn_tcp_key *k1, struct cmn_tcp_key *k2)
+{
+	return (!memcmp(k1, k2, sizeof(struct cmn_tcp_key)));
+}
+
+#endif
diff --git a/lib/gro/gro_tcp4.c b/lib/gro/gro_tcp4.c
index 0014096e63..6645de592b 100644
--- a/lib/gro/gro_tcp4.c
+++ b/lib/gro/gro_tcp4.c
@@ -7,6 +7,7 @@
 #include <rte_ethdev.h>
 
 #include "gro_tcp4.h"
+#include "gro_tcp_internal.h"
 
 void *
 gro_tcp4_tbl_create(uint16_t socket_id,
@@ -30,7 +31,7 @@ gro_tcp4_tbl_create(uint16_t socket_id,
 	if (tbl == NULL)
 		return NULL;
 
-	size = sizeof(struct gro_tcp4_item) * entries_num;
+	size = sizeof(struct gro_tcp_item) * entries_num;
 	tbl->items = rte_zmalloc_socket(__func__,
 			size,
 			RTE_CACHE_LINE_SIZE,
@@ -71,18 +72,6 @@ gro_tcp4_tbl_destroy(void *tbl)
 	rte_free(tcp_tbl);
 }
 
-static inline uint32_t
-find_an_empty_item(struct gro_tcp4_tbl *tbl)
-{
-	uint32_t i;
-	uint32_t max_item_num = tbl->max_item_num;
-
-	for (i = 0; i < max_item_num; i++)
-		if (tbl->items[i].firstseg == NULL)
-			return i;
-	return INVALID_ARRAY_INDEX;
-}
-
 static inline uint32_t
 find_an_empty_flow(struct gro_tcp4_tbl *tbl)
 {
@@ -95,56 +84,6 @@ find_an_empty_flow(struct gro_tcp4_tbl *tbl)
 	return INVALID_ARRAY_INDEX;
 }
 
-static inline uint32_t
-insert_new_item(struct gro_tcp4_tbl *tbl,
-		struct rte_mbuf *pkt,
-		uint64_t start_time,
-		uint32_t prev_idx,
-		uint32_t sent_seq,
-		uint16_t ip_id,
-		uint8_t is_atomic)
-{
-	uint32_t item_idx;
-
-	item_idx = find_an_empty_item(tbl);
-	if (item_idx == INVALID_ARRAY_INDEX)
-		return INVALID_ARRAY_INDEX;
-
-	tbl->items[item_idx].firstseg = pkt;
-	tbl->items[item_idx].lastseg = rte_pktmbuf_lastseg(pkt);
-	tbl->items[item_idx].start_time = start_time;
-	tbl->items[item_idx].next_pkt_idx = INVALID_ARRAY_INDEX;
-	tbl->items[item_idx].sent_seq = sent_seq;
-	tbl->items[item_idx].ip_id = ip_id;
-	tbl->items[item_idx].nb_merged = 1;
-	tbl->items[item_idx].is_atomic = is_atomic;
-	tbl->item_num++;
-
-	/* if the previous packet exists, chain them together. */
-	if (prev_idx != INVALID_ARRAY_INDEX) {
-		tbl->items[item_idx].next_pkt_idx =
-			tbl->items[prev_idx].next_pkt_idx;
-		tbl->items[prev_idx].next_pkt_idx = item_idx;
-	}
-
-	return item_idx;
-}
-
-static inline uint32_t
-delete_item(struct gro_tcp4_tbl *tbl, uint32_t item_idx,
-		uint32_t prev_item_idx)
-{
-	uint32_t next_idx = tbl->items[item_idx].next_pkt_idx;
-
-	/* NULL indicates an empty item */
-	tbl->items[item_idx].firstseg = NULL;
-	tbl->item_num--;
-	if (prev_item_idx != INVALID_ARRAY_INDEX)
-		tbl->items[prev_item_idx].next_pkt_idx = next_idx;
-
-	return next_idx;
-}
-
 static inline uint32_t
 insert_new_flow(struct gro_tcp4_tbl *tbl,
 		struct tcp4_flow_key *src,
@@ -159,13 +98,10 @@ insert_new_flow(struct gro_tcp4_tbl *tbl,
 
 	dst = &(tbl->flows[flow_idx].key);
 
-	rte_ether_addr_copy(&(src->eth_saddr), &(dst->eth_saddr));
-	rte_ether_addr_copy(&(src->eth_daddr), &(dst->eth_daddr));
+	ASSIGN_COMMON_TCP_KEY((&src->cmn_key), (&dst->cmn_key));
+
 	dst->ip_src_addr = src->ip_src_addr;
 	dst->ip_dst_addr = src->ip_dst_addr;
-	dst->recv_ack = src->recv_ack;
-	dst->src_port = src->src_port;
-	dst->dst_port = src->dst_port;
 
 	tbl->flows[flow_idx].start_index = item_idx;
 	tbl->flow_num++;
@@ -173,21 +109,6 @@ insert_new_flow(struct gro_tcp4_tbl *tbl,
 	return flow_idx;
 }
 
-/*
- * update the packet length for the flushed packet.
- */
-static inline void
-update_header(struct gro_tcp4_item *item)
-{
-	struct rte_ipv4_hdr *ipv4_hdr;
-	struct rte_mbuf *pkt = item->firstseg;
-
-	ipv4_hdr = (struct rte_ipv4_hdr *)(rte_pktmbuf_mtod(pkt, char *) +
-			pkt->l2_len);
-	ipv4_hdr->total_length = rte_cpu_to_be_16(pkt->pkt_len -
-			pkt->l2_len);
-}
-
 int32_t
 gro_tcp4_reassemble(struct rte_mbuf *pkt,
 		struct gro_tcp4_tbl *tbl,
@@ -202,9 +123,8 @@ gro_tcp4_reassemble(struct rte_mbuf *pkt,
 	uint8_t is_atomic;
 
 	struct tcp4_flow_key key;
-	uint32_t cur_idx, prev_idx, item_idx;
+	uint32_t item_idx;
 	uint32_t i, max_flow_num, remaining_flow_num;
-	int cmp;
 	uint8_t find;
 
 	/*
@@ -239,6 +159,14 @@ gro_tcp4_reassemble(struct rte_mbuf *pkt,
 	if (tcp_dl <= 0)
 		return -1;
 
+	rte_ether_addr_copy(&(eth_hdr->src_addr), &(key.cmn_key.eth_saddr));
+	rte_ether_addr_copy(&(eth_hdr->dst_addr), &(key.cmn_key.eth_daddr));
+	key.ip_src_addr = ipv4_hdr->src_addr;
+	key.ip_dst_addr = ipv4_hdr->dst_addr;
+	key.cmn_key.src_port = tcp_hdr->src_port;
+	key.cmn_key.dst_port = tcp_hdr->dst_port;
+	key.cmn_key.recv_ack = tcp_hdr->recv_ack;
+
 	/*
 	 * Save IPv4 ID for the packet whose DF bit is 0. For the packet
 	 * whose DF bit is 1, IPv4 ID is ignored.
@@ -246,15 +174,6 @@ gro_tcp4_reassemble(struct rte_mbuf *pkt,
 	frag_off = rte_be_to_cpu_16(ipv4_hdr->fragment_offset);
 	is_atomic = (frag_off & RTE_IPV4_HDR_DF_FLAG) == RTE_IPV4_HDR_DF_FLAG;
 	ip_id = is_atomic ? 0 : rte_be_to_cpu_16(ipv4_hdr->packet_id);
-	sent_seq = rte_be_to_cpu_32(tcp_hdr->sent_seq);
-
-	rte_ether_addr_copy(&(eth_hdr->src_addr), &(key.eth_saddr));
-	rte_ether_addr_copy(&(eth_hdr->dst_addr), &(key.eth_daddr));
-	key.ip_src_addr = ipv4_hdr->src_addr;
-	key.ip_dst_addr = ipv4_hdr->dst_addr;
-	key.src_port = tcp_hdr->src_port;
-	key.dst_port = tcp_hdr->dst_port;
-	key.recv_ack = tcp_hdr->recv_ack;
 
 	/* Search for a matched flow. */
 	max_flow_num = tbl->max_flow_num;
@@ -270,63 +189,44 @@ gro_tcp4_reassemble(struct rte_mbuf *pkt,
 		}
 	}
 
-	/*
-	 * Fail to find a matched flow. Insert a new flow and store the
-	 * packet into the flow.
-	 */
 	if (find == 0) {
-		item_idx = insert_new_item(tbl, pkt, start_time,
-				INVALID_ARRAY_INDEX, sent_seq, ip_id,
-				is_atomic);
+		sent_seq = rte_be_to_cpu_32(tcp_hdr->sent_seq);
+		item_idx = insert_new_tcp_item(pkt, tbl->items, &tbl->item_num,
+						tbl->max_item_num, start_time,
+						INVALID_ARRAY_INDEX, sent_seq, ip_id,
+						is_atomic);
 		if (item_idx == INVALID_ARRAY_INDEX)
 			return -1;
 		if (insert_new_flow(tbl, &key, item_idx) ==
-				INVALID_ARRAY_INDEX) {
+			INVALID_ARRAY_INDEX) {
 			/*
 			 * Fail to insert a new flow, so delete the
 			 * stored packet.
-			 */
-			delete_item(tbl, item_idx, INVALID_ARRAY_INDEX);
+			*/
+			delete_tcp_item(tbl->items, item_idx, &tbl->item_num, INVALID_ARRAY_INDEX);
 			return -1;
 		}
 		return 0;
 	}
 
-	/*
-	 * Check all packets in the flow and try to find a neighbor for
-	 * the input packet.
-	 */
-	cur_idx = tbl->flows[i].start_index;
-	prev_idx = cur_idx;
-	do {
-		cmp = check_seq_option(&(tbl->items[cur_idx]), tcp_hdr,
-				sent_seq, ip_id, pkt->l4_len, tcp_dl, 0,
-				is_atomic);
-		if (cmp) {
-			if (merge_two_tcp4_packets(&(tbl->items[cur_idx]),
-						pkt, cmp, sent_seq, ip_id, 0))
-				return 1;
-			/*
-			 * Fail to merge the two packets, as the packet
-			 * length is greater than the max value. Store
-			 * the packet into the flow.
-			 */
-			if (insert_new_item(tbl, pkt, start_time, cur_idx,
-						sent_seq, ip_id, is_atomic) ==
-					INVALID_ARRAY_INDEX)
-				return -1;
-			return 0;
-		}
-		prev_idx = cur_idx;
-		cur_idx = tbl->items[cur_idx].next_pkt_idx;
-	} while (cur_idx != INVALID_ARRAY_INDEX);
+	return process_tcp_item(pkt, tcp_hdr, tcp_dl, tbl->items, tbl->flows[i].start_index,
+						&tbl->item_num, tbl->max_item_num,
+						ip_id, is_atomic, start_time);
+}
 
-	/* Fail to find a neighbor, so store the packet into the flow. */
-	if (insert_new_item(tbl, pkt, start_time, prev_idx, sent_seq,
-				ip_id, is_atomic) == INVALID_ARRAY_INDEX)
-		return -1;
+/*
+ * update the packet length for the flushed packet.
+ */
+static inline void
+update_header(struct gro_tcp_item *item)
+{
+	struct rte_ipv4_hdr *ipv4_hdr;
+	struct rte_mbuf *pkt = item->firstseg;
 
-	return 0;
+	ipv4_hdr = (struct rte_ipv4_hdr *)(rte_pktmbuf_mtod(pkt, char *) +
+			pkt->l2_len);
+	ipv4_hdr->total_length = rte_cpu_to_be_16(pkt->pkt_len -
+			pkt->l2_len);
 }
 
 uint16_t
@@ -353,7 +253,8 @@ gro_tcp4_tbl_timeout_flush(struct gro_tcp4_tbl *tbl,
 				 * Delete the packet and get the next
 				 * packet in the flow.
 				 */
-				j = delete_item(tbl, j, INVALID_ARRAY_INDEX);
+				j = delete_tcp_item(tbl->items, j,
+							&tbl->item_num, INVALID_ARRAY_INDEX);
 				tbl->flows[i].start_index = j;
 				if (j == INVALID_ARRAY_INDEX)
 					tbl->flow_num--;
diff --git a/lib/gro/gro_tcp4.h b/lib/gro/gro_tcp4.h
index 212f97a042..245e5da486 100644
--- a/lib/gro/gro_tcp4.h
+++ b/lib/gro/gro_tcp4.h
@@ -5,32 +5,15 @@
 #ifndef _GRO_TCP4_H_
 #define _GRO_TCP4_H_
 
-#include <rte_tcp.h>
+#include "gro_tcp.h"
 
-#define INVALID_ARRAY_INDEX 0xffffffffUL
 #define GRO_TCP4_TBL_MAX_ITEM_NUM (1024UL * 1024UL)
 
-/*
- * The max length of a IPv4 packet, which includes the length of the L3
- * header, the L4 header and the data payload.
- */
-#define MAX_IPV4_PKT_LENGTH UINT16_MAX
-
-/* The maximum TCP header length */
-#define MAX_TCP_HLEN 60
-#define INVALID_TCP_HDRLEN(len) \
-	(((len) < sizeof(struct rte_tcp_hdr)) || ((len) > MAX_TCP_HLEN))
-
-/* Header fields representing a TCP/IPv4 flow */
+/* Header fields representing common fields in TCP flow */
 struct tcp4_flow_key {
-	struct rte_ether_addr eth_saddr;
-	struct rte_ether_addr eth_daddr;
+	struct cmn_tcp_key cmn_key;
 	uint32_t ip_src_addr;
 	uint32_t ip_dst_addr;
-
-	uint32_t recv_ack;
-	uint16_t src_port;
-	uint16_t dst_port;
 };
 
 struct gro_tcp4_flow {
@@ -42,42 +25,12 @@ struct gro_tcp4_flow {
 	uint32_t start_index;
 };
 
-struct gro_tcp4_item {
-	/*
-	 * The first MBUF segment of the packet. If the value
-	 * is NULL, it means the item is empty.
-	 */
-	struct rte_mbuf *firstseg;
-	/* The last MBUF segment of the packet */
-	struct rte_mbuf *lastseg;
-	/*
-	 * The time when the first packet is inserted into the table.
-	 * This value won't be updated, even if the packet is merged
-	 * with other packets.
-	 */
-	uint64_t start_time;
-	/*
-	 * next_pkt_idx is used to chain the packets that
-	 * are in the same flow but can't be merged together
-	 * (e.g. caused by packet reordering).
-	 */
-	uint32_t next_pkt_idx;
-	/* TCP sequence number of the packet */
-	uint32_t sent_seq;
-	/* IPv4 ID of the packet */
-	uint16_t ip_id;
-	/* the number of merged packets */
-	uint16_t nb_merged;
-	/* Indicate if IPv4 ID can be ignored */
-	uint8_t is_atomic;
-};
-
 /*
  * TCP/IPv4 reassembly table structure.
  */
 struct gro_tcp4_tbl {
 	/* item array */
-	struct gro_tcp4_item *items;
+	struct gro_tcp_item *items;
 	/* flow array */
 	struct gro_tcp4_flow *flows;
 	/* current item number */
@@ -186,120 +139,9 @@ uint32_t gro_tcp4_tbl_pkt_count(void *tbl);
 static inline int
 is_same_tcp4_flow(struct tcp4_flow_key k1, struct tcp4_flow_key k2)
 {
-	return (rte_is_same_ether_addr(&k1.eth_saddr, &k2.eth_saddr) &&
-			rte_is_same_ether_addr(&k1.eth_daddr, &k2.eth_daddr) &&
-			(k1.ip_src_addr == k2.ip_src_addr) &&
+	return ((k1.ip_src_addr == k2.ip_src_addr) &&
 			(k1.ip_dst_addr == k2.ip_dst_addr) &&
-			(k1.recv_ack == k2.recv_ack) &&
-			(k1.src_port == k2.src_port) &&
-			(k1.dst_port == k2.dst_port));
+			is_same_common_tcp_key(&k1.cmn_key, &k2.cmn_key));
 }
 
-/*
- * Merge two TCP/IPv4 packets without updating checksums.
- * If cmp is larger than 0, append the new packet to the
- * original packet. Otherwise, pre-pend the new packet to
- * the original packet.
- */
-static inline int
-merge_two_tcp4_packets(struct gro_tcp4_item *item,
-		struct rte_mbuf *pkt,
-		int cmp,
-		uint32_t sent_seq,
-		uint16_t ip_id,
-		uint16_t l2_offset)
-{
-	struct rte_mbuf *pkt_head, *pkt_tail, *lastseg;
-	uint16_t hdr_len, l2_len;
-
-	if (cmp > 0) {
-		pkt_head = item->firstseg;
-		pkt_tail = pkt;
-	} else {
-		pkt_head = pkt;
-		pkt_tail = item->firstseg;
-	}
-
-	/* check if the IPv4 packet length is greater than the max value */
-	hdr_len = l2_offset + pkt_head->l2_len + pkt_head->l3_len +
-		pkt_head->l4_len;
-	l2_len = l2_offset > 0 ? pkt_head->outer_l2_len : pkt_head->l2_len;
-	if (unlikely(pkt_head->pkt_len - l2_len + pkt_tail->pkt_len -
-				hdr_len > MAX_IPV4_PKT_LENGTH))
-		return 0;
-
-	/* remove the packet header for the tail packet */
-	rte_pktmbuf_adj(pkt_tail, hdr_len);
-
-	/* chain two packets together */
-	if (cmp > 0) {
-		item->lastseg->next = pkt;
-		item->lastseg = rte_pktmbuf_lastseg(pkt);
-		/* update IP ID to the larger value */
-		item->ip_id = ip_id;
-	} else {
-		lastseg = rte_pktmbuf_lastseg(pkt);
-		lastseg->next = item->firstseg;
-		item->firstseg = pkt;
-		/* update sent_seq to the smaller value */
-		item->sent_seq = sent_seq;
-		item->ip_id = ip_id;
-	}
-	item->nb_merged++;
-
-	/* update MBUF metadata for the merged packet */
-	pkt_head->nb_segs += pkt_tail->nb_segs;
-	pkt_head->pkt_len += pkt_tail->pkt_len;
-
-	return 1;
-}
-
-/*
- * Check if two TCP/IPv4 packets are neighbors.
- */
-static inline int
-check_seq_option(struct gro_tcp4_item *item,
-		struct rte_tcp_hdr *tcph,
-		uint32_t sent_seq,
-		uint16_t ip_id,
-		uint16_t tcp_hl,
-		uint16_t tcp_dl,
-		uint16_t l2_offset,
-		uint8_t is_atomic)
-{
-	struct rte_mbuf *pkt_orig = item->firstseg;
-	struct rte_ipv4_hdr *iph_orig;
-	struct rte_tcp_hdr *tcph_orig;
-	uint16_t len, tcp_hl_orig;
-
-	iph_orig = (struct rte_ipv4_hdr *)(rte_pktmbuf_mtod(pkt_orig, char *) +
-			l2_offset + pkt_orig->l2_len);
-	tcph_orig = (struct rte_tcp_hdr *)((char *)iph_orig + pkt_orig->l3_len);
-	tcp_hl_orig = pkt_orig->l4_len;
-
-	/* Check if TCP option fields equal */
-	len = RTE_MAX(tcp_hl, tcp_hl_orig) - sizeof(struct rte_tcp_hdr);
-	if ((tcp_hl != tcp_hl_orig) || ((len > 0) &&
-				(memcmp(tcph + 1, tcph_orig + 1,
-					len) != 0)))
-		return 0;
-
-	/* Don't merge packets whose DF bits are different */
-	if (unlikely(item->is_atomic ^ is_atomic))
-		return 0;
-
-	/* check if the two packets are neighbors */
-	len = pkt_orig->pkt_len - l2_offset - pkt_orig->l2_len -
-		pkt_orig->l3_len - tcp_hl_orig;
-	if ((sent_seq == item->sent_seq + len) && (is_atomic ||
-				(ip_id == item->ip_id + 1)))
-		/* append the new packet */
-		return 1;
-	else if ((sent_seq + tcp_dl == item->sent_seq) && (is_atomic ||
-				(ip_id + item->nb_merged == item->ip_id)))
-		/* pre-pend the new packet */
-		return -1;
-
-	return 0;
-}
 #endif
diff --git a/lib/gro/gro_tcp_internal.h b/lib/gro/gro_tcp_internal.h
new file mode 100644
index 0000000000..cc84abeaeb
--- /dev/null
+++ b/lib/gro/gro_tcp_internal.h
@@ -0,0 +1,128 @@
+
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2023 Intel Corporation
+ */
+
+#ifndef _GRO_TCP_INTERNAL_H_
+#define _GRO_TCP_INTERNAL_H_
+
+static inline uint32_t
+find_an_empty_item(struct gro_tcp_item *items,
+	uint32_t max_item_num)
+{
+	uint32_t i;
+
+	for (i = 0; i < max_item_num; i++)
+		if (items[i].firstseg == NULL)
+			return i;
+	return INVALID_ARRAY_INDEX;
+}
+
+static inline uint32_t
+insert_new_tcp_item(struct rte_mbuf *pkt,
+		struct gro_tcp_item *items,
+		uint32_t *item_num,
+		uint32_t max_item_num,
+		uint64_t start_time,
+		uint32_t prev_idx,
+		uint32_t sent_seq,
+		uint16_t ip_id,
+		uint8_t is_atomic)
+{
+	uint32_t item_idx;
+
+	item_idx = find_an_empty_item(items, max_item_num);
+	if (item_idx == INVALID_ARRAY_INDEX)
+		return INVALID_ARRAY_INDEX;
+
+	items[item_idx].firstseg = pkt;
+	items[item_idx].lastseg = rte_pktmbuf_lastseg(pkt);
+	items[item_idx].start_time = start_time;
+	items[item_idx].next_pkt_idx = INVALID_ARRAY_INDEX;
+	items[item_idx].sent_seq = sent_seq;
+	items[item_idx].l3.ip_id = ip_id;
+	items[item_idx].nb_merged = 1;
+	items[item_idx].is_atomic = is_atomic;
+	(*item_num) += 1;
+
+	/* if the previous packet exists, chain them together. */
+	if (prev_idx != INVALID_ARRAY_INDEX) {
+		items[item_idx].next_pkt_idx =
+			items[prev_idx].next_pkt_idx;
+		items[prev_idx].next_pkt_idx = item_idx;
+	}
+
+	return item_idx;
+}
+
+static inline uint32_t
+delete_tcp_item(struct gro_tcp_item *items, uint32_t item_idx,
+		uint32_t *item_num,
+		uint32_t prev_item_idx)
+{
+	uint32_t next_idx = items[item_idx].next_pkt_idx;
+
+	/* NULL indicates an empty item */
+	items[item_idx].firstseg = NULL;
+	(*item_num) -= 1;
+	if (prev_item_idx != INVALID_ARRAY_INDEX)
+		items[prev_item_idx].next_pkt_idx = next_idx;
+
+	return next_idx;
+}
+
+static inline int32_t
+process_tcp_item(struct rte_mbuf *pkt,
+	struct rte_tcp_hdr *tcp_hdr,
+	int32_t tcp_dl,
+	struct gro_tcp_item *items,
+	uint32_t item_idx,
+	uint32_t *item_num,
+	uint32_t max_item_num,
+	uint16_t ip_id,
+	uint8_t is_atomic,
+	uint64_t start_time)
+{
+	uint32_t cur_idx;
+	uint32_t prev_idx;
+	int cmp;
+	uint32_t sent_seq;
+
+	sent_seq = rte_be_to_cpu_32(tcp_hdr->sent_seq);
+	/*
+	 * Check all packets in the flow and try to find a neighbor for
+	 * the input packet.
+	 */
+	cur_idx = item_idx;
+	prev_idx = cur_idx;
+	do {
+		cmp = check_seq_option(&items[cur_idx], tcp_hdr,
+				sent_seq, ip_id, pkt->l4_len, tcp_dl, 0,
+				is_atomic);
+		if (cmp) {
+			if (merge_two_tcp_packets(&items[cur_idx],
+						pkt, cmp, sent_seq, ip_id, 0))
+				return 1;
+			/*
+			 * Fail to merge the two packets, as the packet
+			 * length is greater than the max value. Store
+			 * the packet into the flow.
+			 */
+			if (insert_new_tcp_item(pkt, items, item_num, max_item_num,
+						start_time, cur_idx, sent_seq, ip_id, is_atomic) ==
+					INVALID_ARRAY_INDEX)
+				return -1;
+			return 0;
+		}
+		prev_idx = cur_idx;
+		cur_idx = items[cur_idx].next_pkt_idx;
+	} while (cur_idx != INVALID_ARRAY_INDEX);
+
+	/* Fail to find a neighbor, so store the packet into the flow. */
+	if (insert_new_tcp_item(pkt, items, item_num, max_item_num, start_time, prev_idx, sent_seq,
+				ip_id, is_atomic) == INVALID_ARRAY_INDEX)
+		return -1;
+
+	return 0;
+}
+#endif
diff --git a/lib/gro/gro_vxlan_tcp4.c b/lib/gro/gro_vxlan_tcp4.c
index 3be4deb7c7..6ab7001922 100644
--- a/lib/gro/gro_vxlan_tcp4.c
+++ b/lib/gro/gro_vxlan_tcp4.c
@@ -116,7 +116,7 @@ insert_new_item(struct gro_vxlan_tcp4_tbl *tbl,
 	tbl->items[item_idx].inner_item.start_time = start_time;
 	tbl->items[item_idx].inner_item.next_pkt_idx = INVALID_ARRAY_INDEX;
 	tbl->items[item_idx].inner_item.sent_seq = sent_seq;
-	tbl->items[item_idx].inner_item.ip_id = ip_id;
+	tbl->items[item_idx].inner_item.l3.ip_id = ip_id;
 	tbl->items[item_idx].inner_item.nb_merged = 1;
 	tbl->items[item_idx].inner_item.is_atomic = is_atomic;
 	tbl->items[item_idx].outer_ip_id = outer_ip_id;
@@ -163,15 +163,9 @@ insert_new_flow(struct gro_vxlan_tcp4_tbl *tbl,
 
 	dst = &(tbl->flows[flow_idx].key);
 
-	rte_ether_addr_copy(&(src->inner_key.eth_saddr),
-			&(dst->inner_key.eth_saddr));
-	rte_ether_addr_copy(&(src->inner_key.eth_daddr),
-			&(dst->inner_key.eth_daddr));
+	ASSIGN_COMMON_TCP_KEY((&(src->inner_key.cmn_key)), (&(dst->inner_key.cmn_key)));
 	dst->inner_key.ip_src_addr = src->inner_key.ip_src_addr;
 	dst->inner_key.ip_dst_addr = src->inner_key.ip_dst_addr;
-	dst->inner_key.recv_ack = src->inner_key.recv_ack;
-	dst->inner_key.src_port = src->inner_key.src_port;
-	dst->inner_key.dst_port = src->inner_key.dst_port;
 
 	dst->vxlan_hdr.vx_flags = src->vxlan_hdr.vx_flags;
 	dst->vxlan_hdr.vx_vni = src->vxlan_hdr.vx_vni;
@@ -248,7 +242,7 @@ merge_two_vxlan_tcp4_packets(struct gro_vxlan_tcp4_item *item,
 		uint16_t outer_ip_id,
 		uint16_t ip_id)
 {
-	if (merge_two_tcp4_packets(&item->inner_item, pkt, cmp, sent_seq,
+	if (merge_two_tcp_packets(&item->inner_item, pkt, cmp, sent_seq,
 				ip_id, pkt->outer_l2_len +
 				pkt->outer_l3_len)) {
 		/* Update the outer IPv4 ID to the large value. */
@@ -357,13 +351,13 @@ gro_vxlan_tcp4_reassemble(struct rte_mbuf *pkt,
 
 	sent_seq = rte_be_to_cpu_32(tcp_hdr->sent_seq);
 
-	rte_ether_addr_copy(&(eth_hdr->src_addr), &(key.inner_key.eth_saddr));
-	rte_ether_addr_copy(&(eth_hdr->dst_addr), &(key.inner_key.eth_daddr));
+	rte_ether_addr_copy(&(eth_hdr->src_addr), &(key.inner_key.cmn_key.eth_saddr));
+	rte_ether_addr_copy(&(eth_hdr->dst_addr), &(key.inner_key.cmn_key.eth_daddr));
 	key.inner_key.ip_src_addr = ipv4_hdr->src_addr;
 	key.inner_key.ip_dst_addr = ipv4_hdr->dst_addr;
-	key.inner_key.recv_ack = tcp_hdr->recv_ack;
-	key.inner_key.src_port = tcp_hdr->src_port;
-	key.inner_key.dst_port = tcp_hdr->dst_port;
+	key.inner_key.cmn_key.recv_ack = tcp_hdr->recv_ack;
+	key.inner_key.cmn_key.src_port = tcp_hdr->src_port;
+	key.inner_key.cmn_key.dst_port = tcp_hdr->dst_port;
 
 	key.vxlan_hdr.vx_flags = vxlan_hdr->vx_flags;
 	key.vxlan_hdr.vx_vni = vxlan_hdr->vx_vni;
diff --git a/lib/gro/gro_vxlan_tcp4.h b/lib/gro/gro_vxlan_tcp4.h
index 7832942a68..662db01a88 100644
--- a/lib/gro/gro_vxlan_tcp4.h
+++ b/lib/gro/gro_vxlan_tcp4.h
@@ -36,7 +36,7 @@ struct gro_vxlan_tcp4_flow {
 };
 
 struct gro_vxlan_tcp4_item {
-	struct gro_tcp4_item inner_item;
+	struct gro_tcp_item inner_item;
 	/* IPv4 ID in the outer IPv4 header */
 	uint16_t outer_ip_id;
 	/* Indicate if outer IPv4 ID can be ignored */
diff --git a/lib/gro/rte_gro.c b/lib/gro/rte_gro.c
index e35399fd42..ac3d1cdc94 100644
--- a/lib/gro/rte_gro.c
+++ b/lib/gro/rte_gro.c
@@ -147,7 +147,7 @@ rte_gro_reassemble_burst(struct rte_mbuf **pkts,
 	/* allocate a reassembly table for TCP/IPv4 GRO */
 	struct gro_tcp4_tbl tcp_tbl;
 	struct gro_tcp4_flow tcp_flows[RTE_GRO_MAX_BURST_ITEM_NUM];
-	struct gro_tcp4_item tcp_items[RTE_GRO_MAX_BURST_ITEM_NUM] = {{0} };
+	struct gro_tcp_item tcp_items[RTE_GRO_MAX_BURST_ITEM_NUM] = {{0} };
 
 	/* allocate a reassembly table for UDP/IPv4 GRO */
 	struct gro_udp4_tbl udp_tbl;
