[ovs-dev] [RFC v6 09/11] dp-packet: copy data from multi-seg. DPDK mbuf

[Tiago Lam]

From: Michael Qiu <qiudayu at chinac.com>

When doing packet clone, if packet source is from DPDK driver,
multi-segment must be considered, and copy the segment's data one by
one.

Also, lots of DPDK mbuf's info is missed during a copy, like packet
type, ol_flags, etc.  That information is very important for DPDK to do
packets processing.

Co-authored-by: Mark Kavanagh <mark.b.kavanagh at intel.com>

Signed-off-by: Michael Qiu <qiudayu at chinac.com>
Signed-off-by: Mark Kavanagh <mark.b.kavanagh at intel.com>
---
 lib/dp-packet.c   | 74 ++++++++++++++++++++++++++++++++++++++++++++++---------
 lib/dp-packet.h   |  3 +++
 lib/netdev-dpdk.c |  1 +
 3 files changed, 67 insertions(+), 11 deletions(-)

diff --git a/lib/dp-packet.c b/lib/dp-packet.c
index 8d2b313..74e3efe 100644
--- a/lib/dp-packet.c
+++ b/lib/dp-packet.c
@@ -48,6 +48,22 @@ dp_packet_use__(struct dp_packet *b, void *base, size_t allocated,
     dp_packet_init__(b, allocated, source);
 }
 
+#ifdef DPDK_NETDEV
+void
+dp_packet_copy_mbuf_flags(struct dp_packet *dst, const struct dp_packet *src) {
+    ovs_assert(dst != NULL && src != NULL);
+    struct rte_mbuf *buf_dst = &(dst->mbuf);
+    struct rte_mbuf buf_src = src->mbuf;
+
+    buf_dst->nb_segs = buf_src.nb_segs;
+    buf_dst->ol_flags = buf_src.ol_flags;
+    buf_dst->packet_type = buf_src.packet_type;
+    buf_dst->tx_offload = buf_src.tx_offload;
+}
+#else
+#define dp_packet_copy_mbuf_flags(arg1, arg2)
+#endif
+
 /* Initializes 'b' as an empty dp_packet that contains the 'allocated' bytes of
  * memory starting at 'base'.  'base' should be the first byte of a region
  * obtained from malloc().  It will be freed (with free()) if 'b' is resized or
@@ -158,6 +174,49 @@ dp_packet_clone(const struct dp_packet *buffer)
     return dp_packet_clone_with_headroom(buffer, 0);
 }
 
+#ifdef DPDK_NETDEV
+struct dp_packet *
+dp_packet_clone_with_headroom(const struct dp_packet *buffer,
+                              size_t headroom) {
+    struct dp_packet *new_buffer;
+    uint32_t pkt_len = dp_packet_size(buffer);
+
+    /* copy multi-seg data */
+    if (buffer->source == DPBUF_DPDK && buffer->mbuf.nb_segs > 1) {
+        uint32_t offset = 0;
+        void *dst = NULL;
+        struct rte_mbuf *tmbuf = CONST_CAST(struct rte_mbuf *,
+                                                &(buffer->mbuf));
+
+        new_buffer = dp_packet_new_with_headroom(pkt_len, headroom);
+        dp_packet_set_size(new_buffer, pkt_len + headroom);
+        dst = dp_packet_tail(new_buffer);
+
+        while (tmbuf) {
+            rte_memcpy((char *)dst + offset,
+                       rte_pktmbuf_mtod(tmbuf, void *), tmbuf->data_len);
+            offset += tmbuf->data_len;
+            tmbuf = tmbuf->next;
+        }
+    } else {
+        new_buffer = dp_packet_clone_data_with_headroom(dp_packet_data(buffer),
+                                                        pkt_len, headroom);
+    }
+
+    /* Copy the following fields into the returned buffer: l2_pad_size,
+     * l2_5_ofs, l3_ofs, l4_ofs, cutlen, packet_type and md. */
+    memcpy(&new_buffer->l2_pad_size, &buffer->l2_pad_size,
+            sizeof(struct dp_packet) -
+            offsetof(struct dp_packet, l2_pad_size));
+
+    dp_packet_copy_mbuf_flags(new_buffer, buffer);
+    if (dp_packet_rss_valid(new_buffer)) {
+        new_buffer->mbuf.hash.rss = buffer->mbuf.hash.rss;
+    }
+
+    return new_buffer;
+}
+#else
 /* Creates and returns a new dp_packet whose data are copied from 'buffer'.
  * The returned dp_packet will additionally have 'headroom' bytes of
  * headroom. */
@@ -165,32 +224,25 @@ struct dp_packet *
 dp_packet_clone_with_headroom(const struct dp_packet *buffer, size_t headroom)
 {
     struct dp_packet *new_buffer;
+    uint32_t pkt_len = dp_packet_size(buffer);
 
     new_buffer = dp_packet_clone_data_with_headroom(dp_packet_data(buffer),
-                                                 dp_packet_size(buffer),
-                                                 headroom);
+                                                 pkt_len, headroom);
+
     /* Copy the following fields into the returned buffer: l2_pad_size,
      * l2_5_ofs, l3_ofs, l4_ofs, cutlen, packet_type and md. */
     memcpy(&new_buffer->l2_pad_size, &buffer->l2_pad_size,
             sizeof(struct dp_packet) -
             offsetof(struct dp_packet, l2_pad_size));
 
-#ifdef DPDK_NETDEV
-    new_buffer->mbuf.ol_flags = buffer->mbuf.ol_flags;
-#else
     new_buffer->rss_hash_valid = buffer->rss_hash_valid;
-#endif
-
     if (dp_packet_rss_valid(new_buffer)) {
-#ifdef DPDK_NETDEV
-        new_buffer->mbuf.hash.rss = buffer->mbuf.hash.rss;
-#else
         new_buffer->rss_hash = buffer->rss_hash;
-#endif
     }
 
     return new_buffer;
 }
+#endif
 
 /* Creates and returns a new dp_packet that initially contains a copy of the
  * 'size' bytes of data starting at 'data' with no headroom or tailroom. */
diff --git a/lib/dp-packet.h b/lib/dp-packet.h
index fcfa2d6..22faa6a 100644
--- a/lib/dp-packet.h
+++ b/lib/dp-packet.h
@@ -126,6 +126,9 @@ void dp_packet_init_dpdk(struct dp_packet *);
 void dp_packet_init(struct dp_packet *, size_t);
 void dp_packet_uninit(struct dp_packet *);
 
+void dp_packet_copy_mbuf_flags(struct dp_packet *dst,
+                               const struct dp_packet *src);
+
 struct dp_packet *dp_packet_new(size_t);
 struct dp_packet *dp_packet_new_with_headroom(size_t, size_t headroom);
 struct dp_packet *dp_packet_clone(const struct dp_packet *);
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index 8f44691..dfede14 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -2191,6 +2191,7 @@ dpdk_do_tx_copy(struct netdev *netdev, int qid, struct dp_packet_batch *batch)
         memcpy(rte_pktmbuf_mtod(pkts[txcnt], void *),
                dp_packet_data(packet), size);
         dp_packet_set_size((struct dp_packet *)pkts[txcnt], size);
+        dp_packet_copy_mbuf_flags((struct dp_packet *)pkts[txcnt], packet);
 
         txcnt++;
     }
-- 
2.7.4