mbuf: move chaining from ip_frag library

[dpdk.git] / lib / librte_mbuf / rte_mbuf.h

diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index d7c9030..4a93189 100644 (file)
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -1774,6 +1774,44 @@ static inline int rte_pktmbuf_is_contiguous(const struct rte_mbuf *m)
        return !!(m->nb_segs == 1);
 }
 
+/**
+ * Chain an mbuf to another, thereby creating a segmented packet.
+ *
+ * Note: The implementation will do a linear walk over the segments to find
+ * the tail entry. For cases when there are many segments, it's better to
+ * chain the entries manually.
+ *
+ * @param head
+ *   The head of the mbuf chain (the first packet)
+ * @param tail
+ *   The mbuf to put last in the chain
+ *
+ * @return
+ *   - 0, on success.
+ *   - -EOVERFLOW, if the chain is full (256 entries)
+ */
+static inline int rte_pktmbuf_chain(struct rte_mbuf *head, struct rte_mbuf *tail)
+{
+       struct rte_mbuf *cur_tail;
+
+       /* Check for number-of-segments-overflow */
+       if (head->nb_segs + tail->nb_segs >= 1 << (sizeof(head->nb_segs) * 8))
+               return -EOVERFLOW;
+
+       /* Chain 'tail' onto the old tail */
+       cur_tail = rte_pktmbuf_lastseg(head);
+       cur_tail->next = tail;
+
+       /* accumulate number of segments and total length. */
+       head->nb_segs = (uint8_t)(head->nb_segs + tail->nb_segs);
+       head->pkt_len += tail->pkt_len;
+
+       /* pkt_len is only set in the head */
+       tail->pkt_len = tail->data_len;
+
+       return 0;
+}
+
 /**
  * Dump an mbuf structure to the console.
  *