--- /dev/null
+/*-
+ * BSD LICENSE
+ *
+ * Copyright(c) 2017 Intel Corporation. All rights reserved.
+ * 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_GSO_H_
+#define _RTE_GSO_H_
+
+/**
+ * @file
+ * Interface to GSO library
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include <rte_mbuf.h>
+
+/* Minimum GSO segment size. */
+#define RTE_GSO_SEG_SIZE_MIN (sizeof(struct ether_hdr) + \
+ sizeof(struct ipv4_hdr) + sizeof(struct tcp_hdr) + 1)
+
+/* GSO flags for rte_gso_ctx. */
+#define RTE_GSO_FLAG_IPID_FIXED (1ULL << 0)
+/**< Use fixed IP ids for output GSO segments. Setting
+ * 0 indicates using incremental IP ids.
+ */
+
+/**
+ * GSO context structure.
+ */
+struct rte_gso_ctx {
+ struct rte_mempool *direct_pool;
+ /**< MBUF pool for allocating direct buffers, which are used
+ * to store packet headers for GSO segments.
+ */
+ struct rte_mempool *indirect_pool;
+ /**< MBUF pool for allocating indirect buffers, which are used
+ * to locate packet payloads for GSO segments. The indirect
+ * buffer doesn't contain any data, but simply points to an
+ * offset within the packet to segment.
+ */
+ uint64_t flag;
+ /**< flag that controls specific attributes of output segments,
+ * such as the type of IP ID generated (i.e. fixed or incremental).
+ */
+ uint32_t gso_types;
+ /**< the bit mask of required GSO types. The GSO library
+ * uses the same macros as that of describing device TX
+ * offloading capabilities (i.e. DEV_TX_OFFLOAD_*_TSO) for
+ * gso_types.
+ *
+ * For example, if applications want to segment TCP/IPv4
+ * packets, set DEV_TX_OFFLOAD_TCP_TSO in gso_types.
+ */
+ uint16_t gso_size;
+ /**< maximum size of an output GSO segment, including packet
+ * header and payload, measured in bytes. Must exceed
+ * RTE_GSO_SEG_SIZE_MIN.
+ */
+};
+
+/**
+ * Segmentation function, which supports processing of both single- and
+ * multi- MBUF packets.
+ *
+ * Note that we refer to the packets that are segmented from the input
+ * packet as 'GSO segments'. rte_gso_segment() doesn't check if the
+ * input packet has correct checksums, and doesn't update checksums for
+ * output GSO segments. Additionally, it doesn't process IP fragment
+ * packets.
+ *
+ * Before calling rte_gso_segment(), applications must set proper ol_flags
+ * for the packet. The GSO library uses the same macros as that of TSO.
+ * For example, set PKT_TX_TCP_SEG and PKT_TX_IPV4 in ol_flags to segment
+ * a TCP/IPv4 packet. If rte_gso_segment() succceds, the PKT_TX_TCP_SEG
+ * flag is removed for all GSO segments and the input packet.
+ *
+ * Each of the newly-created GSO segments is organized as a two-segment
+ * MBUF, where the first segment is a standard MBUF, which stores a copy
+ * of packet header, and the second is an indirect MBUF which points to
+ * a section of data in the input packet. Since each GSO segment has
+ * multiple MBUFs (i.e. typically 2 MBUFs), the driver of the interface which
+ * the GSO segments are sent to should support transmission of multi-segment
+ * packets.
+ *
+ * If the input packet is GSO'd, its mbuf refcnt reduces by 1. Therefore,
+ * when all GSO segments are freed, the input packet is freed automatically.
+ *
+ * If the memory space in pkts_out or MBUF pools is insufficient, this
+ * function fails, and it returns (-1) * errno. Otherwise, GSO succeeds,
+ * and this function returns the number of output GSO segments filled in
+ * pkts_out.
+ *
+ * @param pkt
+ * The packet mbuf to segment.
+ * @param ctx
+ * GSO context object pointer.
+ * @param pkts_out
+ * Pointer array used to store the MBUF addresses of output GSO
+ * segments, when rte_gso_segment() succeeds.
+ * @param nb_pkts_out
+ * The max number of items that pkts_out can keep.
+ *
+ * @return
+ * - The number of GSO segments filled in pkts_out on success.
+ * - Return -ENOMEM if run out of memory in MBUF pools.
+ * - Return -EINVAL for invalid parameters.
+ */
+int rte_gso_segment(struct rte_mbuf *pkt,
+ const struct rte_gso_ctx *ctx,
+ struct rte_mbuf **pkts_out,
+ uint16_t nb_pkts_out);
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_GSO_H_ */
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