[PATCH v4 3/7] pcapng: add additional mbuf if space required on copy

[Stephen Hemminger <stephen@networkplumber.org>]

If comment is passed to rte_pcapng_copy(), additional space
may be needed at the end of the mbuf. To handle this case generate
a segmented mbuf with additional space for the options.

Fixes: c1abd1e93dbd ("pcapng: support comment in enhanced packet block")
Cc: stable@dpdk.org

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 lib/pcapng/rte_pcapng.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/lib/pcapng/rte_pcapng.c b/lib/pcapng/rte_pcapng.c
index c2635d8b03..f53e6dfecd 100644
--- a/lib/pcapng/rte_pcapng.c
+++ b/lib/pcapng/rte_pcapng.c
@@ -568,11 +568,24 @@ rte_pcapng_copy(uint16_t port_id, uint32_t queue,
 	if (comment)
 		optlen += pcapng_optlen(strlen(comment));
 
-	/* reserve trailing options and block length */
+	/*
+	 * Try to put options at the end of this mbuf.
+	 * If not use an mbuf chain.
+	 */
 	opt = (struct pcapng_option *)
 		rte_pktmbuf_append(mc, optlen + sizeof(uint32_t));
-	if (unlikely(opt == NULL))
-		goto fail;
+	if (unlikely(opt == NULL)) {
+		struct rte_mbuf *ml = rte_pktmbuf_alloc(mp);
+
+		if (unlikely(ml == NULL))
+			goto fail;
+
+		opt = (struct pcapng_option *)rte_pktmbuf_append(ml, optlen + sizeof(uint32_t));
+		if (unlikely(opt == NULL || rte_pktmbuf_chain(mc, ml) != 0)) {
+			rte_pktmbuf_free(ml);
+			goto fail;
+		}
+	}
 
 	switch (direction) {
 	case RTE_PCAPNG_DIRECTION_IN:
-- 
2.51.0