[dpdk-dev] [PATCH v2] net/pcap: truncate packet if it is too large

[Zhike Wang <wangzk320@163.com>]

From: Zhike Wang <wangzhike@jd.com>

Previously large packet would be dropped, instead now it is better to keep it via truncating it.

Signed-off-by: Zhike Wang <wangzk320@163.com>
---
 drivers/net/pcap/rte_eth_pcap.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/drivers/net/pcap/rte_eth_pcap.c b/drivers/net/pcap/rte_eth_pcap.c
index aa7ef6f..b4c79d1 100644
--- a/drivers/net/pcap/rte_eth_pcap.c
+++ b/drivers/net/pcap/rte_eth_pcap.c
@@ -313,7 +313,7 @@ struct pmd_devargs_all {
 	struct pcap_pkthdr header;
 	pcap_dumper_t *dumper;
 	unsigned char temp_data[RTE_ETH_PCAP_SNAPLEN];
-	size_t len;
+	size_t len, caplen;
 
 	pp = rte_eth_devices[dumper_q->port_id].process_private;
 	dumper = pp->tx_dumper[dumper_q->queue_id];
@@ -325,28 +325,24 @@ struct pmd_devargs_all {
 	 * dumper */
 	for (i = 0; i < nb_pkts; i++) {
 		mbuf = bufs[i];
-		len = rte_pktmbuf_pkt_len(mbuf);
+		len = caplen = rte_pktmbuf_pkt_len(mbuf);
 		if (unlikely(!rte_pktmbuf_is_contiguous(mbuf) &&
 				len > sizeof(temp_data))) {
-			PMD_LOG(ERR,
-				"Dropping multi segment PCAP packet. Size (%zd) > max size (%zd).",
-				len, sizeof(temp_data));
-			rte_pktmbuf_free(mbuf);
-			continue;
+			caplen = sizeof(temp_data);
 		}
 
 		calculate_timestamp(&header.ts);
 		header.len = len;
-		header.caplen = header.len;
+		header.caplen = caplen;
 		/* rte_pktmbuf_read() returns a pointer to the data directly
 		 * in the mbuf (when the mbuf is contiguous) or, otherwise,
 		 * a pointer to temp_data after copying into it.
 		 */
 		pcap_dump((u_char *)dumper, &header,
-			rte_pktmbuf_read(mbuf, 0, len, temp_data));
+			rte_pktmbuf_read(mbuf, 0, caplen, temp_data));
 
 		num_tx++;
-		tx_bytes += len;
+		tx_bytes += caplen;
 		rte_pktmbuf_free(mbuf);
 	}
 
-- 
1.8.3.1