[PATCH v1] ip_frag: add IPv4 fragment copy packet API

[Huichao Cai <chcchc88@163.com>]

Some NIC drivers support MBUF_FAST_FREE(Device supports optimization
for fast release of mbufs. When set application must guarantee that
per-queue all mbufs comes from the same mempool and has refcnt = 1)
offload. In order to adapt to this offload function, add this API.
Add some test data for this API.

Signed-off-by: Huichao Cai <chcchc88@163.com>
---
 app/test/test_ipfrag.c               |   8 +-
 lib/ip_frag/rte_ip_frag.h            |  26 ++++++
 lib/ip_frag/rte_ipv4_fragmentation.c | 165 +++++++++++++++++++++++++++++++++++
 lib/ip_frag/version.map              |   1 +
 4 files changed, 199 insertions(+), 1 deletion(-)

diff --git a/app/test/test_ipfrag.c b/app/test/test_ipfrag.c
index 610a86b..e565e86 100644
--- a/app/test/test_ipfrag.c
+++ b/app/test/test_ipfrag.c
@@ -408,10 +408,16 @@ static void ut_teardown(void)
 		}
 
 		if (tests[i].ipv == 4)
-			len = rte_ipv4_fragment_packet(b, pkts_out, BURST,
+			if (i % 2)
+				len = rte_ipv4_fragment_packet(b, pkts_out,
+						       BURST,
 						       tests[i].mtu_size,
 						       direct_pool,
 						       indirect_pool);
+			else
+				len = rte_ipv4_fragment_copy_packet(b, pkts_out,
+							   BURST,
+							   tests[i].mtu_size);
 		else if (tests[i].ipv == 6)
 			len = rte_ipv6_fragment_packet(b, pkts_out, BURST,
 						       tests[i].mtu_size,
diff --git a/lib/ip_frag/rte_ip_frag.h b/lib/ip_frag/rte_ip_frag.h
index 7d2abe1..767320b 100644
--- a/lib/ip_frag/rte_ip_frag.h
+++ b/lib/ip_frag/rte_ip_frag.h
@@ -179,6 +179,32 @@ int32_t rte_ipv4_fragment_packet(struct rte_mbuf *pkt_in,
 			struct rte_mempool *pool_indirect);
 
 /**
+ * IPv4 fragmentation by copy.
+ *
+ * This function implements the fragmentation of IPv4 packets by copy.
+ *
+ * @param pkt_in
+ *   The input packet.
+ * @param pkts_out
+ *   Array storing the output fragments.
+ * @param nb_pkts_out
+ *   The size of the array that stores the output fragments.
+ * @param mtu_size
+ *   Size in bytes of the Maximum Transfer Unit (MTU) for the outgoing IPv4
+ *   datagrams. This value includes the size of the IPv4 header.
+ * @return
+ *   Upon successful completion - number of output fragments placed
+ *   in the pkts_out array.
+ *   Otherwise - (-1) * <errno>.
+ */
+__rte_experimental
+int32_t
+rte_ipv4_fragment_copy_packet(struct rte_mbuf *pkt_in,
+	struct rte_mbuf **pkts_out,
+	uint16_t nb_pkts_out,
+	uint16_t mtu_size);
+
+/**
  * This function implements reassembly of fragmented IPv4 packets.
  * Incoming mbufs should have its l2_len/l3_len fields setup correctly.
  *
diff --git a/lib/ip_frag/rte_ipv4_fragmentation.c b/lib/ip_frag/rte_ipv4_fragmentation.c
index a562424..1142b5a 100644
--- a/lib/ip_frag/rte_ipv4_fragmentation.c
+++ b/lib/ip_frag/rte_ipv4_fragmentation.c
@@ -262,3 +262,168 @@ static inline uint16_t __create_ipopt_frag_hdr(uint8_t *iph,
 
 	return out_pkt_pos;
 }
+
+/**
+ * IPv4 fragmentation by copy.
+ *
+ * This function implements the fragmentation of IPv4 packets by copy.
+ *
+ * @param pkt_in
+ *   The input packet.
+ * @param pkts_out
+ *   Array storing the output fragments.
+ * @param nb_pkts_out
+ *   The size of the array that stores the output fragments.
+ * @param mtu_size
+ *   Size in bytes of the Maximum Transfer Unit (MTU) for the outgoing IPv4
+ *   datagrams. This value includes the size of the IPv4 header.
+ * @return
+ *   Upon successful completion - number of output fragments placed
+ *   in the pkts_out array.
+ *   Otherwise - (-1) * <errno>.
+ */
+int32_t
+rte_ipv4_fragment_copy_packet(struct rte_mbuf *pkt_in,
+	struct rte_mbuf **pkts_out,
+	uint16_t nb_pkts_out,
+	uint16_t mtu_size)
+{
+	struct rte_mbuf *in_seg = NULL;
+	struct rte_ipv4_hdr *in_hdr;
+	uint32_t out_pkt_pos, in_seg_data_pos;
+	uint32_t more_in_segs;
+	uint16_t fragment_offset, flag_offset, frag_size, header_len;
+	uint16_t frag_bytes_remaining;
+	uint8_t ipopt_frag_hdr[IPV4_HDR_MAX_LEN];
+	uint16_t ipopt_len;
+
+	/*
+	 * Formal parameter checking.
+	 */
+	if (unlikely(pkt_in == NULL) || unlikely(pkts_out == NULL) ||
+	    unlikely(nb_pkts_out == 0) ||
+	    unlikely(pkt_in->pool == NULL) ||
+	    unlikely(mtu_size < RTE_ETHER_MIN_MTU))
+		return -EINVAL;
+
+	in_hdr = rte_pktmbuf_mtod(pkt_in, struct rte_ipv4_hdr *);
+	header_len = (in_hdr->version_ihl & RTE_IPV4_HDR_IHL_MASK) *
+	    RTE_IPV4_IHL_MULTIPLIER;
+
+	/* Check IP header length */
+	if (unlikely(pkt_in->data_len < header_len) ||
+	    unlikely(mtu_size < header_len))
+		return -EINVAL;
+
+	/*
+	 * Ensure the IP payload length of all fragments is aligned to a
+	 * multiple of 8 bytes as per RFC791 section 2.3.
+	 */
+	frag_size = RTE_ALIGN_FLOOR((mtu_size - header_len),
+				    IPV4_HDR_FO_ALIGN);
+
+	flag_offset = rte_cpu_to_be_16(in_hdr->fragment_offset);
+
+	/* If Don't Fragment flag is set */
+	if (unlikely((flag_offset & IPV4_HDR_DF_MASK) != 0))
+		return -ENOTSUP;
+
+	/* Check that pkts_out is big enough to hold all fragments */
+	if (unlikely(frag_size * nb_pkts_out <
+	    (uint16_t)(pkt_in->pkt_len - header_len)))
+		return -EINVAL;
+
+	in_seg = pkt_in;
+	in_seg_data_pos = header_len;
+	out_pkt_pos = 0;
+	fragment_offset = 0;
+
+	ipopt_len = header_len - sizeof(struct rte_ipv4_hdr);
+	if (unlikely(ipopt_len > RTE_IPV4_HDR_OPT_MAX_LEN))
+		return -EINVAL;
+
+	more_in_segs = 1;
+	while (likely(more_in_segs)) {
+		struct rte_mbuf *out_pkt = NULL;
+		uint32_t more_out_segs;
+		struct rte_ipv4_hdr *out_hdr;
+
+		/* Allocate buffer from pkt_in->pool*/
+		out_pkt = rte_pktmbuf_alloc(pkt_in->pool);
+		if (unlikely(out_pkt == NULL)) {
+			__free_fragments(pkts_out, out_pkt_pos);
+			return -ENOMEM;
+		}
+
+		/* Reserve space for the IP header that will be built later */
+		out_pkt->data_len = header_len;
+		out_pkt->pkt_len = header_len;
+		frag_bytes_remaining = frag_size;
+
+		more_out_segs = 1;
+		while (likely(more_out_segs && more_in_segs)) {
+			uint32_t len;
+
+			len = frag_bytes_remaining;
+			if (len > (in_seg->data_len - in_seg_data_pos))
+				len = in_seg->data_len - in_seg_data_pos;
+
+			rte_memcpy(
+			    rte_pktmbuf_mtod_offset(
+				    out_pkt, char *, out_pkt->pkt_len),
+			    rte_pktmbuf_mtod_offset(
+				    in_seg, char *, in_seg_data_pos),
+			    len);
+			out_pkt->data_len = (uint16_t)(len +
+				out_pkt->data_len);
+
+			out_pkt->pkt_len = (uint16_t)(len +
+				out_pkt->pkt_len);
+			in_seg_data_pos += len;
+			frag_bytes_remaining -= len;
+
+			/* Current output packet (i.e. fragment) done ? */
+			if (unlikely(frag_bytes_remaining == 0))
+				more_out_segs = 0;
+
+			/* Current input segment done ? */
+			if (unlikely(in_seg_data_pos == in_seg->data_len)) {
+				in_seg = in_seg->next;
+				in_seg_data_pos = 0;
+
+				if (unlikely(in_seg == NULL))
+					more_in_segs = 0;
+			}
+		}
+
+		/* Build the IP header */
+
+		out_hdr = rte_pktmbuf_mtod(out_pkt, struct rte_ipv4_hdr *);
+
+		__fill_ipv4hdr_frag(out_hdr, in_hdr, header_len,
+		    (uint16_t)out_pkt->pkt_len,
+		    flag_offset, fragment_offset, more_in_segs);
+
+		if (unlikely((fragment_offset == 0) && (ipopt_len) &&
+			    ((flag_offset & RTE_IPV4_HDR_OFFSET_MASK) == 0))) {
+			ipopt_len = __create_ipopt_frag_hdr((uint8_t *)in_hdr,
+				ipopt_len, ipopt_frag_hdr);
+			fragment_offset = (uint16_t)(fragment_offset +
+				out_pkt->pkt_len - header_len);
+			out_pkt->l3_len = header_len;
+
+			header_len = sizeof(struct rte_ipv4_hdr) + ipopt_len;
+			in_hdr = (struct rte_ipv4_hdr *)ipopt_frag_hdr;
+		} else {
+			fragment_offset = (uint16_t)(fragment_offset +
+				out_pkt->pkt_len - header_len);
+			out_pkt->l3_len = header_len;
+		}
+
+		/* Write the fragment to the output list */
+		pkts_out[out_pkt_pos] = out_pkt;
+		out_pkt_pos++;
+	}
+
+	return out_pkt_pos;
+}
diff --git a/lib/ip_frag/version.map b/lib/ip_frag/version.map
index e537224..4aa66bc 100644
--- a/lib/ip_frag/version.map
+++ b/lib/ip_frag/version.map
@@ -17,4 +17,5 @@ EXPERIMENTAL {
 	global:
 
 	rte_ip_frag_table_del_expired_entries;
+	rte_ipv4_fragment_copy_packet;
 };
-- 
1.8.3.1