diff --git a/lib/librte_gro/Makefile b/lib/librte_gro/Makefile
index 9f4063a..3495dfc 100644
--- a/lib/librte_gro/Makefile
+++ b/lib/librte_gro/Makefile
@@ -43,6 +43,7 @@ LIBABIVER := 1
 
 # source files
 SRCS-$(CONFIG_RTE_LIBRTE_GRO) += rte_gro.c
+SRCS-$(CONFIG_RTE_LIBRTE_GRO) += rte_gro_tcp.c
 
 # install this header file
 SYMLINK-$(CONFIG_RTE_LIBRTE_GRO)-include += rte_gro.h
diff --git a/lib/librte_gro/rte_gro.c b/lib/librte_gro/rte_gro.c
index ca6b0d2..f2defbd 100644
--- a/lib/librte_gro/rte_gro.c
+++ b/lib/librte_gro/rte_gro.c
@@ -31,11 +31,17 @@
 
 #include <rte_malloc.h>
 #include <rte_mbuf.h>
+#include <rte_ethdev.h>
+#include <rte_ip.h>
+#include <rte_tcp.h>
 
 #include "rte_gro.h"
+#include "rte_gro_tcp.h"
 
-static gro_tbl_create_fn tbl_create_functions[GRO_TYPE_MAX_NB];
-static gro_tbl_destroy_fn tbl_destroy_functions[GRO_TYPE_MAX_NB];
+static gro_tbl_create_fn tbl_create_functions[GRO_TYPE_MAX_NB] = {
+	gro_tcp_tbl_create, NULL};
+static gro_tbl_destroy_fn tbl_destroy_functions[GRO_TYPE_MAX_NB] = {
+	gro_tcp_tbl_destroy, NULL};
 
 struct rte_gro_tbl *rte_gro_tbl_create(uint16_t socket_id,
 		uint16_t max_flow_num,
@@ -93,33 +99,145 @@ void rte_gro_tbl_destroy(struct rte_gro_tbl *gro_tbl)
 }
 
 uint16_t
-rte_gro_reassemble_burst(struct rte_mbuf **pkts __rte_unused,
+rte_gro_reassemble_burst(struct rte_mbuf **pkts,
 		const uint16_t nb_pkts,
-		const struct rte_gro_param param __rte_unused)
+		const struct rte_gro_param param)
 {
-	return nb_pkts;
+	struct ether_hdr *eth_hdr;
+	struct ipv4_hdr *ipv4_hdr;
+	uint16_t l3proc_type, i;
+	uint16_t nb_after_gro = nb_pkts;
+	const uint64_t item_num = nb_pkts >
+		param.max_flow_num * param.max_item_per_flow ?
+		param.max_flow_num * param.max_item_per_flow :
+		nb_pkts;
+	const uint32_t flow_num = nb_pkts > param.max_flow_num ?
+		param.max_flow_num : nb_pkts;
+
+	/* allocate respective GRO tables for all supported GRO types */
+	struct gro_tcp_tbl tcp_tbl;
+	struct gro_tcp_flow tcp_flows[flow_num];
+	struct gro_tcp_item tcp_items[item_num];
+	struct gro_tcp_rule tcp_rule;
+
+	struct rte_mbuf *unprocess_pkts[nb_pkts];
+	uint16_t unprocess_num = 0;
+	int32_t ret;
+
+	if (unlikely(nb_pkts <= 1))
+		return nb_pkts;
+
+	memset(tcp_flows, 0, sizeof(struct gro_tcp_flow) *
+			flow_num);
+	memset(tcp_items, 0, sizeof(struct gro_tcp_item) *
+			item_num);
+	tcp_tbl.flows = tcp_flows;
+	tcp_tbl.items = tcp_items;
+	tcp_tbl.flow_num = 0;
+	tcp_tbl.item_num = 0;
+	tcp_tbl.max_flow_num = flow_num;
+	tcp_tbl.max_item_num = item_num;
+	tcp_rule.max_packet_size = param.max_packet_size;
+
+	for (i = 0; i < nb_pkts; i++) {
+		eth_hdr = rte_pktmbuf_mtod(pkts[i], struct ether_hdr *);
+		l3proc_type = rte_be_to_cpu_16(eth_hdr->ether_type);
+		if (l3proc_type == ETHER_TYPE_IPv4) {
+			ipv4_hdr = (struct ipv4_hdr *)(eth_hdr + 1);
+			if (ipv4_hdr->next_proto_id == IPPROTO_TCP &&
+					(param.desired_gro_types &
+					 GRO_TCP_IPV4)) {
+				ret = gro_tcp4_reassemble(pkts[i],
+						&tcp_tbl,
+						&tcp_rule);
+				if (ret > 0)
+					nb_after_gro--;
+				else if (ret < 0)
+					unprocess_pkts[unprocess_num++] =
+						pkts[i];
+			} else
+				unprocess_pkts[unprocess_num++] =
+					pkts[i];
+		} else
+			unprocess_pkts[unprocess_num++] =
+				pkts[i];
+	}
+
+	if (nb_after_gro < nb_pkts) {
+		/* update packets headers and re-arrange GROed packets */
+		if (param.desired_gro_types & GRO_TCP_IPV4) {
+			gro_tcp4_tbl_cksum_update(&tcp_tbl);
+			for (i = 0; i < tcp_tbl.item_num; i++)
+				pkts[i] = tcp_tbl.items[i].pkt;
+		}
+		if (unprocess_num > 0) {
+			memcpy(&pkts[i], unprocess_pkts,
+					sizeof(struct rte_mbuf *) *
+					unprocess_num);
+			i += unprocess_num;
+		}
+		if (nb_pkts > i)
+			memset(&pkts[i], 0,
+					sizeof(struct rte_mbuf *) *
+					(nb_pkts - i));
+	}
+	return nb_after_gro;
 }
 
-int rte_gro_reassemble(struct rte_mbuf *pkt __rte_unused,
-		struct rte_gro_tbl *gro_tbl __rte_unused)
+int rte_gro_reassemble(struct rte_mbuf *pkt,
+		struct rte_gro_tbl *gro_tbl)
 {
+	struct ether_hdr *eth_hdr;
+	struct ipv4_hdr *ipv4_hdr;
+	uint16_t l3proc_type;
+	struct gro_tcp_rule tcp_rule;
+
+	if (pkt == NULL)
+		return -1;
+	tcp_rule.max_packet_size = gro_tbl->max_packet_size;
+	eth_hdr = rte_pktmbuf_mtod(pkt, struct ether_hdr *);
+	l3proc_type = rte_be_to_cpu_16(eth_hdr->ether_type);
+	if (l3proc_type == ETHER_TYPE_IPv4) {
+		ipv4_hdr = (struct ipv4_hdr *)(eth_hdr + 1);
+		if (ipv4_hdr->next_proto_id == IPPROTO_TCP &&
+				(gro_tbl->desired_gro_types & GRO_TCP_IPV4)) {
+			return gro_tcp4_reassemble(pkt,
+					gro_tbl->tbls[GRO_TCP_IPV4_INDEX],
+					&tcp_rule);
+		}
+	}
 	return -1;
 }
 
-uint16_t rte_gro_flush(struct rte_gro_tbl *gro_tbl __rte_unused,
-		uint64_t desired_gro_types __rte_unused,
-		uint16_t flush_num __rte_unused,
-		struct rte_mbuf **out __rte_unused,
-		const uint16_t max_nb_out __rte_unused)
+uint16_t rte_gro_flush(struct rte_gro_tbl *gro_tbl,
+		uint64_t desired_gro_types,
+		uint16_t flush_num,
+		struct rte_mbuf **out,
+		const uint16_t max_nb_out)
 {
+	desired_gro_types = desired_gro_types &
+		gro_tbl->desired_gro_types;
+	if (desired_gro_types & GRO_TCP_IPV4)
+		return gro_tcp_tbl_flush(
+				gro_tbl->tbls[GRO_TCP_IPV4_INDEX],
+				flush_num,
+				out,
+				max_nb_out);
 	return 0;
 }
 
 uint16_t
-rte_gro_timeout_flush(struct rte_gro_tbl *gro_tbl __rte_unused,
-		uint64_t desired_gro_types __rte_unused,
-		struct rte_mbuf **out __rte_unused,
-		const uint16_t max_nb_out __rte_unused)
+rte_gro_timeout_flush(struct rte_gro_tbl *gro_tbl,
+		uint64_t desired_gro_types,
+		struct rte_mbuf **out,
+		const uint16_t max_nb_out)
 {
+	desired_gro_types = desired_gro_types &
+		gro_tbl->desired_gro_types;
+	if (desired_gro_types & GRO_TCP_IPV4)
+		return gro_tcp_tbl_timeout_flush(
+				gro_tbl->tbls[GRO_TCP_IPV4_INDEX],
+				gro_tbl->max_timeout_cycles,
+				out, max_nb_out);
 	return 0;
 }
diff --git a/lib/librte_gro/rte_gro.h b/lib/librte_gro/rte_gro.h
index 7fe11a6..24e3e34 100644
--- a/lib/librte_gro/rte_gro.h
+++ b/lib/librte_gro/rte_gro.h
@@ -34,7 +34,11 @@
 
 /* maximum number of supported GRO types */
 #define GRO_TYPE_MAX_NB 64
-#define GRO_TYPE_SUPPORT_NB 0	/**< current supported GRO num */
+#define GRO_TYPE_SUPPORT_NB 1	/**< supported GRO types number */
+
+/* TCP/IPv4 GRO flag */
+#define GRO_TCP_IPV4_INDEX 0
+#define GRO_TCP_IPV4 (1ULL << GRO_TCP_IPV4_INDEX)
 
 /**
  * GRO table structure. DPDK GRO uses GRO table to reassemble
@@ -138,9 +142,9 @@ void rte_gro_tbl_destroy(struct rte_gro_tbl *gro_tbl);
  * @return
  *  the number of packets after GROed.
  */
-uint16_t rte_gro_reassemble_burst(struct rte_mbuf **pkts __rte_unused,
-		const uint16_t nb_pkts __rte_unused,
-		const struct rte_gro_param param __rte_unused);
+uint16_t rte_gro_reassemble_burst(struct rte_mbuf **pkts,
+		const uint16_t nb_pkts,
+		const struct rte_gro_param param);
 
 /**
  * This is the main reassembly API used in heavyweight mode, which
@@ -163,8 +167,8 @@ uint16_t rte_gro_reassemble_burst(struct rte_mbuf **pkts __rte_unused,
  *  if merge the packet successfully, return a positive value. If fail
  *  to merge, return zero. If errors happen, return a negative value.
  */
-int rte_gro_reassemble(struct rte_mbuf *pkt __rte_unused,
-		struct rte_gro_tbl *gro_tbl __rte_unused);
+int rte_gro_reassemble(struct rte_mbuf *pkt,
+		struct rte_gro_tbl *gro_tbl);
 
 /**
  * This function flushed packets of desired GRO types from their
@@ -183,11 +187,11 @@ int rte_gro_reassemble(struct rte_mbuf *pkt __rte_unused,
  * @return
  *  the number of flushed packets. If no packets are flushed, return 0.
  */
-uint16_t rte_gro_flush(struct rte_gro_tbl *gro_tbl __rte_unused,
-		uint64_t desired_gro_types __rte_unused,
-		uint16_t flush_num __rte_unused,
-		struct rte_mbuf **out __rte_unused,
-		const uint16_t max_nb_out __rte_unused);
+uint16_t rte_gro_flush(struct rte_gro_tbl *gro_tbl,
+		uint64_t desired_gro_types,
+		uint16_t flush_num,
+		struct rte_mbuf **out,
+		const uint16_t max_nb_out);
 
 /**
  * This function flushes the timeout packets from reassembly tables of
@@ -205,8 +209,8 @@ uint16_t rte_gro_flush(struct rte_gro_tbl *gro_tbl __rte_unused,
  * @return
  *  the number of flushed packets. If no packets are flushed, return 0.
  */
-uint16_t rte_gro_timeout_flush(struct rte_gro_tbl *gro_tbl __rte_unused,
-		uint64_t desired_gro_types __rte_unused,
-		struct rte_mbuf **out __rte_unused,
-		const uint16_t max_nb_out __rte_unused);
+uint16_t rte_gro_timeout_flush(struct rte_gro_tbl *gro_tbl,
+		uint64_t desired_gro_types,
+		struct rte_mbuf **out,
+		const uint16_t max_nb_out);
 #endif
diff --git a/lib/librte_gro/rte_gro_tcp.c b/lib/librte_gro/rte_gro_tcp.c
new file mode 100644
index 0000000..15f28f4
--- /dev/null
+++ b/lib/librte_gro/rte_gro_tcp.c
@@ -0,0 +1,509 @@
+/*-
+ *
+ *   Copyright(c) 2016-2017 Intel Corporation. All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <rte_malloc.h>
+#include <rte_mbuf.h>
+#include <rte_cycles.h>
+#include <rte_ethdev.h>
+#include <rte_ip.h>
+#include <rte_tcp.h>
+
+#include "rte_gro_tcp.h"
+
+void *gro_tcp_tbl_create(uint16_t socket_id,
+		uint16_t max_flow_num,
+		uint16_t max_item_per_flow)
+{
+	size_t size;
+	uint32_t entries_num;
+	struct gro_tcp_tbl *tbl;
+
+	entries_num = max_flow_num * max_item_per_flow;
+	if (entries_num == 0 || max_flow_num == 0)
+		return NULL;
+
+	tbl = (struct gro_tcp_tbl *)rte_zmalloc_socket(
+			__func__,
+			sizeof(struct gro_tcp_tbl),
+			RTE_CACHE_LINE_SIZE,
+			socket_id);
+
+	size = sizeof(struct gro_tcp_item) * entries_num;
+	tbl->items = (struct gro_tcp_item *)rte_zmalloc_socket(
+			__func__,
+			size,
+			RTE_CACHE_LINE_SIZE,
+			socket_id);
+	tbl->max_item_num = entries_num;
+
+	size = sizeof(struct gro_tcp_flow) * max_flow_num;
+	tbl->flows = (struct gro_tcp_flow *)rte_zmalloc_socket(
+			__func__,
+			size, RTE_CACHE_LINE_SIZE,
+			socket_id);
+	tbl->max_flow_num = max_flow_num;
+	return tbl;
+}
+
+void gro_tcp_tbl_destroy(void *tbl)
+{
+	struct gro_tcp_tbl *tcp_tbl = (struct gro_tcp_tbl *)tbl;
+
+	if (tcp_tbl) {
+		if (tcp_tbl->items)
+			rte_free(tcp_tbl->items);
+		if (tcp_tbl->flows)
+			rte_free(tcp_tbl->flows);
+		rte_free(tcp_tbl);
+	}
+}
+
+/* update TCP header and IPv4 header checksum */
+static void
+gro_tcp4_cksum_update(struct rte_mbuf *pkt)
+{
+	uint32_t len, offset, cksum;
+	struct ether_hdr *eth_hdr;
+	struct ipv4_hdr *ipv4_hdr;
+	struct tcp_hdr *tcp_hdr;
+	uint16_t ipv4_ihl, cksum_pld;
+
+	if (pkt == NULL)
+		return;
+
+	len = pkt->pkt_len;
+	eth_hdr = rte_pktmbuf_mtod(pkt, struct ether_hdr *);
+	ipv4_hdr = (struct ipv4_hdr *)(eth_hdr + 1);
+	ipv4_ihl = IPv4_HDR_LEN(ipv4_hdr);
+	tcp_hdr = (struct tcp_hdr *)((char *)ipv4_hdr + ipv4_ihl);
+
+	offset = sizeof(struct ether_hdr) + ipv4_ihl;
+	len -= offset;
+
+	/* TCP cksum without IP pseudo header */
+	ipv4_hdr->hdr_checksum = 0;
+	tcp_hdr->cksum = 0;
+	if (rte_raw_cksum_mbuf(pkt, offset, len, &cksum_pld) < 0) {
+		printf("invalid param for raw_cksum_mbuf\n");
+		return;
+	}
+	/* IP pseudo header cksum */
+	cksum = cksum_pld;
+	cksum += rte_ipv4_phdr_cksum(ipv4_hdr, 0);
+
+	/* combine TCP checksum and IP pseudo header checksum */
+	cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff);
+	cksum = (~cksum) & 0xffff;
+	cksum = (cksum == 0) ? 0xffff : cksum;
+	tcp_hdr->cksum = cksum;
+
+	/* update IP header cksum */
+	ipv4_hdr->hdr_checksum = rte_ipv4_cksum(ipv4_hdr);
+}
+
+void gro_tcp4_tbl_cksum_update(struct gro_tcp_tbl *tbl)
+{
+	uint64_t i;
+
+	for (i = 0; i < tbl->item_num; i++) {
+		if (tbl->items[i].is_groed)
+			gro_tcp4_cksum_update(tbl->items[i].pkt);
+	}
+}
+
+/**
+ * merge two TCP/IPv4 packets without update header checksum.
+ */
+static int
+merge_two_tcp4_packets(struct rte_mbuf *pkt_src,
+		struct rte_mbuf *pkt,
+		struct gro_tcp_rule *rule)
+{
+	struct ipv4_hdr *ipv4_hdr1, *ipv4_hdr2;
+	struct tcp_hdr *tcp_hdr1;
+	uint16_t ipv4_ihl1, tcp_hl1, tcp_dl1;
+	struct rte_mbuf *tail;
+
+	/* parse the given packet */
+	ipv4_hdr1 = (struct ipv4_hdr *)(rte_pktmbuf_mtod(pkt,
+				struct ether_hdr *) + 1);
+	ipv4_ihl1 = IPv4_HDR_LEN(ipv4_hdr1);
+	tcp_hdr1 = (struct tcp_hdr *)((char *)ipv4_hdr1 + ipv4_ihl1);
+	tcp_hl1 = TCP_HDR_LEN(tcp_hdr1);
+	tcp_dl1 = rte_be_to_cpu_16(ipv4_hdr1->total_length) - ipv4_ihl1
+		- tcp_hl1;
+
+	/* parse the original packet */
+	ipv4_hdr2 = (struct ipv4_hdr *)(rte_pktmbuf_mtod(pkt_src,
+				struct ether_hdr *) + 1);
+
+	/* check reassembly rules */
+	if (pkt_src->pkt_len + tcp_dl1 > rule->max_packet_size)
+		return -1;
+
+	/* remove the header of the incoming packet */
+	rte_pktmbuf_adj(pkt, sizeof(struct ether_hdr) +
+			ipv4_ihl1 + tcp_hl1);
+
+	/* chain the two packet together */
+	tail = rte_pktmbuf_lastseg(pkt_src);
+	tail->next = pkt;
+
+	/* update IP header */
+	ipv4_hdr2->total_length = rte_cpu_to_be_16(
+			rte_be_to_cpu_16(
+				ipv4_hdr2->total_length)
+			+ tcp_dl1);
+
+	/* update mbuf metadata for the merged packet */
+	pkt_src->nb_segs++;
+	pkt_src->pkt_len += pkt->pkt_len;
+	return 1;
+}
+
+static int
+check_seq_option(struct rte_mbuf *pkt,
+		struct tcp_hdr *tcp_hdr,
+		uint16_t tcp_hl)
+{
+	struct ipv4_hdr *ipv4_hdr1;
+	struct tcp_hdr *tcp_hdr1;
+	uint16_t ipv4_ihl1, tcp_hl1, tcp_dl1;
+	uint32_t sent_seq1, sent_seq;
+	int ret = -1;
+
+	ipv4_hdr1 = (struct ipv4_hdr *)(rte_pktmbuf_mtod(pkt,
+				struct ether_hdr *) + 1);
+	ipv4_ihl1 = IPv4_HDR_LEN(ipv4_hdr1);
+	tcp_hdr1 = (struct tcp_hdr *)((char *)ipv4_hdr1 + ipv4_ihl1);
+	tcp_hl1 = TCP_HDR_LEN(tcp_hdr1);
+	tcp_dl1 = rte_be_to_cpu_16(ipv4_hdr1->total_length) - ipv4_ihl1
+		- tcp_hl1;
+	sent_seq1 = rte_be_to_cpu_32(tcp_hdr1->sent_seq) + tcp_dl1;
+	sent_seq = rte_be_to_cpu_32(tcp_hdr->sent_seq);
+
+	/* check if the two packets are neighbor */
+	if ((sent_seq ^ sent_seq1) == 0) {
+		/* check if the option fields equal */
+		if (tcp_hl1 > sizeof(struct tcp_hdr)) {
+			if ((tcp_hl1 != tcp_hl) ||
+					(memcmp(tcp_hdr1 + 1,
+							tcp_hdr + 1,
+							tcp_hl - sizeof
+							(struct tcp_hdr))
+					 == 0))
+				ret = 1;
+		}
+	}
+	return ret;
+}
+
+static uint32_t
+find_an_empty_item(struct gro_tcp_tbl *tbl)
+{
+	uint32_t i;
+
+	for (i = 0; i < tbl->max_item_num; i++)
+		if (tbl->items[i].is_valid == 0)
+			return i;
+	return INVALID_ITEM_INDEX;
+}
+
+static uint16_t
+find_an_empty_flow(struct gro_tcp_tbl *tbl)
+{
+	uint16_t i;
+
+	for (i = 0; i < tbl->max_flow_num; i++)
+		if (tbl->flows[i].is_valid == 0)
+			return i;
+	return INVALID_FLOW_INDEX;
+}
+
+int32_t
+gro_tcp4_reassemble(struct rte_mbuf *pkt,
+		struct gro_tcp_tbl *tbl,
+		struct gro_tcp_rule *rule)
+{
+	struct ether_hdr *eth_hdr;
+	struct ipv4_hdr *ipv4_hdr;
+	struct tcp_hdr *tcp_hdr;
+	uint16_t ipv4_ihl, tcp_hl, tcp_dl, tcp_cksum, ip_cksum;
+
+	struct gro_tcp_flow_key key;
+	uint64_t ol_flags;
+	uint32_t cur_idx, prev_idx, item_idx;
+	uint16_t i, flow_idx;
+
+	eth_hdr = rte_pktmbuf_mtod(pkt, struct ether_hdr *);
+	ipv4_hdr = (struct ipv4_hdr *)(eth_hdr + 1);
+	ipv4_ihl = IPv4_HDR_LEN(ipv4_hdr);
+
+	/* 1. check if the packet should be processed */
+	if (ipv4_ihl < sizeof(struct ipv4_hdr))
+		goto fail;
+	if (ipv4_hdr->next_proto_id != IPPROTO_TCP)
+		goto fail;
+	if ((ipv4_hdr->fragment_offset &
+				rte_cpu_to_be_16(IPV4_HDR_DF_MASK))
+			== 0)
+		goto fail;
+
+	tcp_hdr = (struct tcp_hdr *)((char *)ipv4_hdr + ipv4_ihl);
+	tcp_hl = TCP_HDR_LEN(tcp_hdr);
+	tcp_dl = rte_be_to_cpu_16(ipv4_hdr->total_length) - ipv4_ihl
+		- tcp_hl;
+	if (tcp_dl == 0)
+		goto fail;
+
+	/**
+	 * 2. if HW rx checksum offload isn't enabled, recalculate the
+	 * checksum in SW. Then, check if the checksum is correct
+	 */
+	ol_flags = pkt->ol_flags;
+	if ((ol_flags & PKT_RX_IP_CKSUM_MASK) !=
+			PKT_RX_IP_CKSUM_UNKNOWN) {
+		if (ol_flags == PKT_RX_IP_CKSUM_BAD)
+			goto fail;
+	} else {
+		ip_cksum = ipv4_hdr->hdr_checksum;
+		ipv4_hdr->hdr_checksum = 0;
+		ipv4_hdr->hdr_checksum = rte_ipv4_cksum(ipv4_hdr);
+		if (ipv4_hdr->hdr_checksum ^ ip_cksum)
+			goto fail;
+	}
+
+	if ((ol_flags & PKT_RX_L4_CKSUM_MASK) !=
+			PKT_RX_L4_CKSUM_UNKNOWN) {
+		if (ol_flags == PKT_RX_L4_CKSUM_BAD)
+			goto fail;
+	} else {
+		tcp_cksum = tcp_hdr->cksum;
+		tcp_hdr->cksum = 0;
+		tcp_hdr->cksum = rte_ipv4_udptcp_cksum
+			(ipv4_hdr, tcp_hdr);
+		if (tcp_hdr->cksum ^ tcp_cksum)
+			goto fail;
+	}
+
+	/**
+	 * 3. search for a flow and traverse all packets in the flow
+	 * to find one to merge with the given packet.
+	 */
+	key.eth_saddr = eth_hdr->s_addr;
+	key.eth_daddr = eth_hdr->d_addr;
+	key.ip_src_addr[0] = rte_be_to_cpu_32(ipv4_hdr->src_addr);
+	key.ip_dst_addr[0] = rte_be_to_cpu_32(ipv4_hdr->dst_addr);
+	key.src_port = rte_be_to_cpu_16(tcp_hdr->src_port);
+	key.dst_port = rte_be_to_cpu_16(tcp_hdr->dst_port);
+	key.recv_ack = rte_be_to_cpu_32(tcp_hdr->recv_ack);
+	key.tcp_flags = tcp_hdr->tcp_flags;
+
+	for (i = 0; i < tbl->max_flow_num; i++) {
+		/* search all packets in a valid flow. */
+		if (tbl->flows[i].is_valid &&
+				(memcmp(&(tbl->flows[i].key), &key,
+						sizeof(struct gro_tcp_flow_key))
+				 == 0)) {
+			cur_idx = tbl->flows[i].start_index;
+			prev_idx = cur_idx;
+			while (cur_idx != INVALID_ITEM_INDEX) {
+				if (check_seq_option(tbl->items[cur_idx].pkt,
+							tcp_hdr,
+							tcp_hl) > 0) {
+					if (merge_two_tcp4_packets(
+								tbl->items[cur_idx].pkt,
+								pkt,
+								rule) > 0) {
+						/* successfully merge two packets */
+						tbl->items[cur_idx].is_groed = 1;
+						return 1;
+					}
+					/**
+					 * fail to merge two packets since
+					 * break the rules, add the packet
+					 * into the flow.
+					 */
+					goto insert_to_existed_flow;
+				} else {
+					prev_idx = cur_idx;
+					cur_idx = tbl->items[cur_idx].next_pkt_idx;
+				}
+			}
+			/**
+			 * fail to merge the given packet into an existed flow,
+			 * add it into the flow.
+			 */
+insert_to_existed_flow:
+			item_idx = find_an_empty_item(tbl);
+			/* the item number is beyond the maximum value */
+			if (item_idx == INVALID_ITEM_INDEX)
+				return -1;
+			tbl->items[prev_idx].next_pkt_idx = item_idx;
+			tbl->items[item_idx].pkt = pkt;
+			tbl->items[item_idx].is_groed = 0;
+			tbl->items[item_idx].next_pkt_idx = INVALID_ITEM_INDEX;
+			tbl->items[item_idx].is_valid = 1;
+			tbl->items[item_idx].start_time = rte_rdtsc();
+			tbl->item_num++;
+			return 0;
+		}
+	}
+
+	/**
+	 * merge fail as the given packet is a new flow. Therefore,
+	 * insert a new flow.
+	 */
+	item_idx = find_an_empty_item(tbl);
+	flow_idx = find_an_empty_flow(tbl);
+	/**
+	 * if the flow or item number are beyond the maximum values,
+	 * the inputted packet won't be processed.
+	 */
+	if (item_idx == INVALID_ITEM_INDEX ||
+			flow_idx == INVALID_FLOW_INDEX)
+		return -1;
+	tbl->items[item_idx].pkt = pkt;
+	tbl->items[item_idx].next_pkt_idx = INVALID_ITEM_INDEX;
+	tbl->items[item_idx].is_groed = 0;
+	tbl->items[item_idx].is_valid = 1;
+	tbl->items[item_idx].start_time = rte_rdtsc();
+	tbl->item_num++;
+
+	memcpy(&(tbl->flows[flow_idx].key),
+			&key, sizeof(struct gro_tcp_flow_key));
+	tbl->flows[flow_idx].start_index = item_idx;
+	tbl->flows[flow_idx].is_valid = 1;
+	tbl->flow_num++;
+
+	return 0;
+fail:
+	return -1;
+}
+
+uint16_t gro_tcp_tbl_flush(struct gro_tcp_tbl *tbl,
+		uint16_t flush_num,
+		struct rte_mbuf **out,
+		const uint16_t nb_out)
+{
+	uint16_t num, k;
+	uint16_t i;
+	uint32_t j;
+
+	k = 0;
+	num = tbl->item_num > flush_num ? flush_num : tbl->item_num;
+	num = num > nb_out ? nb_out : num;
+	if (num == 0)
+		return 0;
+
+	for (i = 0; i < tbl->max_flow_num; i++) {
+		if (tbl->flows[i].is_valid) {
+			j = tbl->flows[i].start_index;
+			while (j != INVALID_ITEM_INDEX) {
+				/* update checksum for GROed packet */
+				if (tbl->items[j].is_groed)
+					gro_tcp4_cksum_update(tbl->items[j].pkt);
+
+				out[k++] = tbl->items[j].pkt;
+				tbl->items[j].is_valid = 0;
+				tbl->item_num--;
+				j = tbl->items[j].next_pkt_idx;
+
+				if (k == num) {
+					/* delete the flow */
+					if (j == INVALID_ITEM_INDEX) {
+						tbl->flows[i].is_valid = 0;
+						tbl->flow_num--;
+					} else
+						/* update flow information */
+						tbl->flows[i].start_index = j;
+					goto end;
+				}
+			}
+			/* delete the flow, as all of its packets are flushed */
+			tbl->flows[i].is_valid = 0;
+			tbl->flow_num--;
+		}
+	}
+end:
+	return num;
+}
+
+uint16_t
+gro_tcp_tbl_timeout_flush(struct gro_tcp_tbl *tbl,
+		uint64_t timeout_cycles,
+		struct rte_mbuf **out,
+		const uint16_t nb_out)
+{
+	uint16_t k;
+	uint16_t i;
+	uint32_t j;
+	uint64_t current_time;
+
+	if (nb_out == 0)
+		return 0;
+	k = 0;
+	current_time = rte_rdtsc();
+
+	for (i = 0; i < tbl->max_flow_num; i++) {
+		if (tbl->flows[i].is_valid) {
+			j = tbl->flows[i].start_index;
+			while (j != INVALID_ITEM_INDEX) {
+				if (current_time - tbl->items[j].start_time >=
+						timeout_cycles) {
+					/* update checksum for GROed packet */
+					if (tbl->items[j].is_groed)
+						gro_tcp4_cksum_update(tbl->items[j].pkt);
+
+					out[k++] = tbl->items[j].pkt;
+					tbl->items[j].is_valid = 0;
+					tbl->item_num--;
+					j = tbl->items[j].next_pkt_idx;
+
+					if (k == nb_out) {
+						if (j == INVALID_ITEM_INDEX) {
+							/* delete the flow */
+							tbl->flows[i].is_valid = 0;
+							tbl->flow_num--;
+						} else
+							tbl->flows[i].start_index = j;
+						goto end;
+					}
+				}
+			}
+			/* delete the flow, as all of its packets are flushed */
+			tbl->flows[i].is_valid = 0;
+			tbl->flow_num--;
+		}
+	}
+end:
+	return k;
+}
diff --git a/lib/librte_gro/rte_gro_tcp.h b/lib/librte_gro/rte_gro_tcp.h
new file mode 100644
index 0000000..76b2107
--- /dev/null
+++ b/lib/librte_gro/rte_gro_tcp.h
@@ -0,0 +1,206 @@
+/*-
+ *
+ *   Copyright(c) 2016-2017 Intel Corporation. All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _RTE_GRO_TCP_H_
+#define _RTE_GRO_TCP_H_
+
+#if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN
+#define TCP_HDR_LEN(tcph) \
+	((tcph->data_off >> 4) * 4)
+#define IPv4_HDR_LEN(iph) \
+	((iph->version_ihl & 0x0f) * 4)
+#else
+#define TCP_DATAOFF_MASK 0x0f
+#define TCP_HDR_LEN(tcph) \
+	((tcph->data_off & TCP_DATAOFF_MASK) * 4)
+#define IPv4_HDR_LEN(iph) \
+	((iph->version_ihl >> 4) * 4)
+#endif
+
+#define IPV4_HDR_DF_SHIFT 14
+#define IPV4_HDR_DF_MASK (1 << IPV4_HDR_DF_SHIFT)
+
+#define INVALID_FLOW_INDEX 0xffffUL
+#define INVALID_ITEM_INDEX 0xffffffffULL
+
+/* criteria of mergeing packets */
+struct gro_tcp_flow_key {
+	struct ether_addr eth_saddr;
+	struct ether_addr eth_daddr;
+	uint32_t ip_src_addr[4];	/**< IPv4 uses the first 8B */
+	uint32_t ip_dst_addr[4];
+
+	uint32_t recv_ack;	/**< acknowledgment sequence number. */
+	uint16_t src_port;
+	uint16_t dst_port;
+	uint8_t tcp_flags;	/**< TCP flags. */
+};
+
+struct gro_tcp_flow {
+	struct gro_tcp_flow_key key;
+	uint32_t start_index;	/**< the first packet index of the flow */
+	uint8_t is_valid;
+};
+
+struct gro_tcp_item {
+	struct rte_mbuf *pkt;	/**< packet address. */
+	/* the time when the packet in added into the table */
+	uint64_t start_time;
+	uint32_t next_pkt_idx;	/**< next packet index. */
+	/* flag to indicate if the packet is GROed */
+	uint8_t is_groed;
+	uint8_t is_valid;	/**< flag indicates if the item is valid */
+};
+
+/**
+ * TCP reassembly table. Both TCP/IPv4 and TCP/IPv6 use the same table
+ * structure.
+ */
+struct gro_tcp_tbl {
+	struct gro_tcp_item *items;	/**< item array */
+	struct gro_tcp_flow *flows;	/**< flow array */
+	uint32_t item_num;	/**< current item number */
+	uint16_t flow_num;	/**< current flow num */
+	uint32_t max_item_num;	/**< item array size */
+	uint16_t max_flow_num;	/**< flow array size */
+};
+
+/* rules to reassemble TCP packets, which are decided by applications */
+struct gro_tcp_rule {
+	/* the maximum packet length after merged */
+	uint32_t max_packet_size;
+};
+
+/**
+ * This function is to update TCP and IPv4 header checksums
+ * for merged packets in the TCP reassembly table.
+ */
+void gro_tcp4_tbl_cksum_update(struct gro_tcp_tbl *tbl);
+
+/**
+ * This function creates a TCP reassembly table.
+ *
+ * @param socket_id
+ *  socket index where the Ethernet port connects to.
+ * @param max_flow_num
+ *  the maximum number of flows in the TCP GRO table
+ * @param max_item_per_flow
+ *  the maximum packet number per flow.
+ * @return
+ *  if create successfully, return a pointer which points to the
+ *  created TCP GRO table. Otherwise, return NULL.
+ */
+void *gro_tcp_tbl_create(uint16_t socket_id,
+		uint16_t max_flow_num,
+		uint16_t max_item_per_flow);
+
+/**
+ * This function destroys a TCP reassembly table.
+ * @param tbl
+ *  a pointer points to the TCP reassembly table.
+ */
+void gro_tcp_tbl_destroy(void *tbl);
+
+/**
+ * This function searches for a packet in the TCP reassembly table to
+ * merge with the inputted one. To merge two packets is to chain them
+ * together and update packet headers. Note that this function won't
+ * re-calculate IPv4 and TCP checksums.
+ *
+ * If the packet doesn't have data, or with wrong checksums, or is
+ * fragmented etc., errors happen and gro_tcp4_reassemble returns
+ * immediately. If no errors happen, the packet is either merged, or
+ * inserted into the reassembly table.
+ *
+ * If applications want to get packets in the reassembly table, they
+ * need to manually flush the packets.
+ *
+ * @param pkt
+ *  packet to reassemble.
+ * @param tbl
+ *  a pointer that points to a TCP reassembly table.
+ * @param rule
+ *  TCP reassembly criteria defined by applications.
+ * @return
+ *  if the inputted packet is merged successfully, return an positive
+ *  value. If the packet hasn't be merged with any packets in the TCP
+ *  reassembly table. If errors happen, return a negative value and the
+ *  packet won't be inserted into the reassemble table.
+ */
+int32_t
+gro_tcp4_reassemble(struct rte_mbuf *pkt,
+		struct gro_tcp_tbl *tbl,
+		struct gro_tcp_rule *rule);
+
+/**
+ * This function flushes the packets in a TCP reassembly table to
+ * applications. Before returning the packets, it will update TCP and
+ * IPv4 header checksums.
+ *
+ * @param tbl
+ *  a pointer that points to a TCP GRO table.
+ * @param flush_num
+ *  the number of packets that applications want to flush.
+ * @param out
+ *  pointer array which is used to keep flushed packets.
+ * @param nb_out
+ *  the maximum element number of out.
+ * @return
+ *  the number of packets that are flushed finally.
+ */
+uint16_t
+gro_tcp_tbl_flush(struct gro_tcp_tbl *tbl,
+		uint16_t flush_num,
+		struct rte_mbuf **out,
+		const uint16_t nb_out);
+
+/**
+ * This function flushes timeout packets in a TCP reassembly table to
+ * applications. Before returning the packets, it updates TCP and IPv4
+ * header checksums.
+ *
+ * @param tbl
+ *  a pointer that points to a TCP GRO table.
+ * @param timeout_cycles
+ *  the maximum time that packets can stay in the table.
+ * @param out
+ *  pointer array which is used to keep flushed packets.
+ * @param nb_out
+ *  the maximum element number of out.
+ * @return
+ *  It returns the number of packets that are flushed finally.
+ */
+uint16_t
+gro_tcp_tbl_timeout_flush(struct gro_tcp_tbl *tbl,
+		uint64_t timeout_cycles,
+		struct rte_mbuf **out,
+		const uint16_t nb_out);
+#endif
