mbuf: add a copy routine

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

diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
index 9a1a1b5..0236fba 100644 (file)
--- a/lib/librte_mbuf/rte_mbuf.c
+++ b/lib/librte_mbuf/rte_mbuf.c
@@ -321,6 +321,83 @@ __rte_pktmbuf_linearize(struct rte_mbuf *mbuf)
        return 0;
 }
 
+/* Create a deep copy of mbuf */
+struct rte_mbuf *
+rte_pktmbuf_copy(const struct rte_mbuf *m, struct rte_mempool *mp,
+                uint32_t off, uint32_t len)
+{
+       const struct rte_mbuf *seg = m;
+       struct rte_mbuf *mc, *m_last, **prev;
+
+       /* garbage in check */
+       __rte_mbuf_sanity_check(m, 1);
+
+       /* check for request to copy at offset past end of mbuf */
+       if (unlikely(off >= m->pkt_len))
+               return NULL;
+
+       mc = rte_pktmbuf_alloc(mp);
+       if (unlikely(mc == NULL))
+               return NULL;
+
+       /* truncate requested length to available data */
+       if (len > m->pkt_len - off)
+               len = m->pkt_len - off;
+
+       __rte_pktmbuf_copy_hdr(mc, m);
+
+       /* copied mbuf is not indirect or external */
+       mc->ol_flags = m->ol_flags & ~(IND_ATTACHED_MBUF|EXT_ATTACHED_MBUF);
+
+       prev = &mc->next;
+       m_last = mc;
+       while (len > 0) {
+               uint32_t copy_len;
+
+               /* skip leading mbuf segments */
+               while (off >= seg->data_len) {
+                       off -= seg->data_len;
+                       seg = seg->next;
+               }
+
+               /* current buffer is full, chain a new one */
+               if (rte_pktmbuf_tailroom(m_last) == 0) {
+                       m_last = rte_pktmbuf_alloc(mp);
+                       if (unlikely(m_last == NULL)) {
+                               rte_pktmbuf_free(mc);
+                               return NULL;
+                       }
+                       ++mc->nb_segs;
+                       *prev = m_last;
+                       prev = &m_last->next;
+               }
+
+               /*
+                * copy the min of data in input segment (seg)
+                * vs space available in output (m_last)
+                */
+               copy_len = RTE_MIN(seg->data_len - off, len);
+               if (copy_len > rte_pktmbuf_tailroom(m_last))
+                       copy_len = rte_pktmbuf_tailroom(m_last);
+
+               /* append from seg to m_last */
+               rte_memcpy(rte_pktmbuf_mtod_offset(m_last, char *,
+                                                  m_last->data_len),
+                          rte_pktmbuf_mtod_offset(seg, char *, off),
+                          copy_len);
+
+               /* update offsets and lengths */
+               m_last->data_len += copy_len;
+               mc->pkt_len += copy_len;
+               off += copy_len;
+               len -= copy_len;
+       }
+
+       /* garbage out check */
+       __rte_mbuf_sanity_check(mc, 1);
+       return mc;
+}
+
 /* dump a mbuf on console */
 void
 rte_pktmbuf_dump(FILE *f, const struct rte_mbuf *m, unsigned dump_len)