ip_frag: add IPv4 fragment copy

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, has refcnt = 1, direct
and non-segmented.) 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>
Acked-by: Konstantin Ananyev <konstantin.v.ananyev@yandex.ru>

app/test/test_ipfrag.c

@@ -418,10 +418,17 @@ test_ip_frag(void)
 		}
 
 		if (tests[i].ipv == 4)
+			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_nonseg_packet(b,
+						       pkts_out,
+						       BURST,
+						       tests[i].mtu_size,
+						       direct_pool);
 		else if (tests[i].ipv == 6)
 			len = rte_ipv6_fragment_packet(b, pkts_out, BURST,
 						       tests[i].mtu_size,

lib/ip_frag/rte_ip_frag.h

@@ -178,6 +178,40 @@ int32_t rte_ipv4_fragment_packet(struct rte_mbuf *pkt_in,
 			struct rte_mempool *pool_direct,
 			struct rte_mempool *pool_indirect);
 
+/**
+ * IPv4 fragmentation by copy.
+ *
+ * This function implements the fragmentation of IPv4 packets by copy
+ * non-segmented mbuf.
+ * This function is mainly used to adapt Tx MBUF_FAST_FREE offload.
+ * 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, has refcnt = 1, direct and non-segmented.
+ *
+ * @param pkt_in
+ *   The input packet.
+ * @param pkts_out
+ *   Array storing the output fragments.
+ * @param nb_pkts_out
+ *   Number of 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.
+ * @param pool_direct
+ *   MBUF pool used for allocating direct buffers for the output fragments.
+ * @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_nonseg_packet(struct rte_mbuf *pkt_in,
+	struct rte_mbuf **pkts_out,
+	uint16_t nb_pkts_out,
+	uint16_t mtu_size,
+	struct rte_mempool *pool_direct);
+
 /**
  * This function implements reassembly of fragmented IPv4 packets.
  * Incoming mbufs should have its l2_len/l3_len fields setup correctly.

lib/ip_frag/rte_ipv4_fragmentation.c

@@ -259,3 +259,177 @@ rte_ipv4_fragment_packet(struct rte_mbuf *pkt_in,
 
 	return out_pkt_pos;
 }
+
+/**
+ * IPv4 fragmentation by copy.
+ *
+ * This function implements the fragmentation of IPv4 packets by copy
+ * non-segmented mbuf.
+ * This function is mainly used to adapt Tx MBUF_FAST_FREE offload.
+ * 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, has refcnt = 1, direct and non-segmented.
+ *
+ * @param pkt_in
+ *   The input packet.
+ * @param pkts_out
+ *   Array storing the output fragments.
+ * @param nb_pkts_out
+ *   Number of 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.
+ * @param pool_direct
+ *   MBUF pool used for allocating direct buffers for the output fragments.
+ * @return
+ *   Upon successful completion - number of output fragments placed
+ *   in the pkts_out array.
+ *   Otherwise - (-1) * errno.
+ */
+int32_t
+rte_ipv4_fragment_copy_nonseg_packet(struct rte_mbuf *pkt_in,
+	struct rte_mbuf **pkts_out,
+	uint16_t nb_pkts_out,
+	uint16_t mtu_size,
+	struct rte_mempool *pool_direct)
+{
+	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(pool_direct == 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 direct buffer */
+		out_pkt = rte_pktmbuf_alloc(pool_direct);
+		if (unlikely(out_pkt == NULL)) {
+			__free_fragments(pkts_out, out_pkt_pos);
+			return -ENOMEM;
+		}
+		if (unlikely(rte_pktmbuf_tailroom(out_pkt) < frag_size)) {
+			rte_pktmbuf_free(out_pkt);
+			__free_fragments(pkts_out, out_pkt_pos);
+			return -EINVAL;
+		}
+
+		/* 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;
+
+			memcpy(rte_pktmbuf_mtod_offset(out_pkt, char *,
+					out_pkt->data_len),
+				rte_pktmbuf_mtod_offset(in_seg, char *,
+					in_seg_data_pos),
+				len);
+
+			in_seg_data_pos += len;
+			frag_bytes_remaining -= len;
+			out_pkt->data_len += 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_pkt->pkt_len = out_pkt->data_len;
+		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;
+}

lib/ip_frag/version.map

@@ -17,4 +17,5 @@ EXPERIMENTAL {
 	global:
 
 	rte_ip_frag_table_del_expired_entries;
+	rte_ipv4_fragment_copy_nonseg_packet;
 };