[PATCH v4] pcap: support MTU set

[Ido Goshen <ido@cgstowernetworks.com>]

Support rte_eth_dev_set_mtu by pcap vdevs
Enforce mtu on rx/tx

Bugzilla ID: 961
Signed-off-by: Ido Goshen <ido@cgstowernetworks.com>

---
v4:
1. Add release notes comment
2. Access pmd internals via queue struct
3. eth_mtu_set code convention fixes

v3:
Preserve pcap behavior to support max size packets by default
alternative to v2 in order to limit the code change to pcap only and
avoid abi change.
Enforce mtu only in case rte_eth_dev_set_mtu was explicitly called.

v2:
Preserve pcap behavior to support max size packets by default.
---
 doc/guides/rel_notes/release_22_07.rst |  3 ++
 drivers/net/pcap/pcap_ethdev.c         | 38 ++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/doc/guides/rel_notes/release_22_07.rst b/doc/guides/rel_notes/release_22_07.rst
index 0ed4f92820..717191d498 100644
--- a/doc/guides/rel_notes/release_22_07.rst
+++ b/doc/guides/rel_notes/release_22_07.rst
@@ -95,6 +95,9 @@ New Features
   * Added AH mode support in lookaside protocol (IPsec) for CN9K & CN10K.
   * Added AES-GMAC support in lookaside protocol (IPsec) for CN9K & CN10K.
 
+* **Updated pcap driver.**
+
+ * Added support for MTU via ``rte_eth_dev_set_mtu``
 
 Removed Items
 -------------
diff --git a/drivers/net/pcap/pcap_ethdev.c b/drivers/net/pcap/pcap_ethdev.c
index ec29fd6bc5..db1958f20f 100644
--- a/drivers/net/pcap/pcap_ethdev.c
+++ b/drivers/net/pcap/pcap_ethdev.c
@@ -74,6 +74,7 @@ struct pcap_rx_queue {
 
 	/* Contains pre-generated packets to be looped through */
 	struct rte_ring *pkts;
+	struct pmd_internals *internals;
 };
 
 struct pcap_tx_queue {
@@ -82,6 +83,7 @@ struct pcap_tx_queue {
 	struct queue_stat tx_stat;
 	char name[PATH_MAX];
 	char type[ETH_PCAP_ARG_MAXLEN];
+	struct pmd_internals *internals;
 };
 
 struct pmd_internals {
@@ -93,6 +95,7 @@ struct pmd_internals {
 	int single_iface;
 	int phy_mac;
 	unsigned int infinite_rx;
+	uint16_t mtu;
 };
 
 struct pmd_process_private {
@@ -278,6 +281,7 @@ eth_pcap_rx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 	const u_char *packet;
 	struct rte_mbuf *mbuf;
 	struct pcap_rx_queue *pcap_q = queue;
+	struct pmd_internals *internals = pcap_q->internals;
 	uint16_t num_rx = 0;
 	uint32_t rx_bytes = 0;
 	pcap_t *pcap;
@@ -303,6 +307,12 @@ eth_pcap_rx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 			break;
 		}
 
+		if (unlikely(header.caplen > internals->mtu)) {
+			pcap_q->rx_stat.err_pkts++;
+			rte_pktmbuf_free(mbuf);
+			break;
+		}
+
 		if (header.caplen <= rte_pktmbuf_tailroom(mbuf)) {
 			/* pcap packet will fit in the mbuf, can copy it */
 			rte_memcpy(rte_pktmbuf_mtod(mbuf, void *), packet,
@@ -378,6 +388,7 @@ eth_pcap_tx_dumper(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 	struct rte_mbuf *mbuf;
 	struct pmd_process_private *pp;
 	struct pcap_tx_queue *dumper_q = queue;
+	struct pmd_internals *internals = dumper_q->internals;
 	uint16_t num_tx = 0;
 	uint32_t tx_bytes = 0;
 	struct pcap_pkthdr header;
@@ -396,6 +407,12 @@ eth_pcap_tx_dumper(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 	for (i = 0; i < nb_pkts; i++) {
 		mbuf = bufs[i];
 		len = caplen = rte_pktmbuf_pkt_len(mbuf);
+
+		if (unlikely(len > internals->mtu)) {
+			rte_pktmbuf_free(mbuf);
+			continue;
+		}
+
 		if (unlikely(!rte_pktmbuf_is_contiguous(mbuf) &&
 				len > sizeof(temp_data))) {
 			caplen = sizeof(temp_data);
@@ -464,6 +481,7 @@ eth_pcap_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 	struct rte_mbuf *mbuf;
 	struct pmd_process_private *pp;
 	struct pcap_tx_queue *tx_queue = queue;
+	struct pmd_internals *internals = tx_queue->internals;
 	uint16_t num_tx = 0;
 	uint32_t tx_bytes = 0;
 	pcap_t *pcap;
@@ -479,6 +497,12 @@ eth_pcap_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 	for (i = 0; i < nb_pkts; i++) {
 		mbuf = bufs[i];
 		len = rte_pktmbuf_pkt_len(mbuf);
+
+		if (unlikely(len > internals->mtu)) {
+			rte_pktmbuf_free(mbuf);
+			continue;
+		}
+
 		if (unlikely(!rte_pktmbuf_is_contiguous(mbuf) &&
 				len > sizeof(temp_data))) {
 			PMD_LOG(ERR,
@@ -807,6 +831,16 @@ eth_stats_reset(struct rte_eth_dev *dev)
 	return 0;
 }
 
+static int
+eth_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)
+{
+	struct pmd_internals *internals = dev->data->dev_private;
+
+	PMD_LOG(INFO, "MTU set %s %u\n", dev->device->name, mtu);
+	internals->mtu = mtu;
+	return 0;
+}
+
 static inline void
 infinite_rx_ring_free(struct rte_ring *pkts)
 {
@@ -878,6 +912,7 @@ eth_rx_queue_setup(struct rte_eth_dev *dev,
 	pcap_q->mb_pool = mb_pool;
 	pcap_q->port_id = dev->data->port_id;
 	pcap_q->queue_id = rx_queue_id;
+	pcap_q->internals = internals;
 	dev->data->rx_queues[rx_queue_id] = pcap_q;
 
 	if (internals->infinite_rx) {
@@ -952,6 +987,7 @@ eth_tx_queue_setup(struct rte_eth_dev *dev,
 
 	pcap_q->port_id = dev->data->port_id;
 	pcap_q->queue_id = tx_queue_id;
+	pcap_q->internals = internals;
 	dev->data->tx_queues[tx_queue_id] = pcap_q;
 
 	return 0;
@@ -1004,6 +1040,7 @@ static const struct eth_dev_ops ops = {
 	.link_update = eth_link_update,
 	.stats_get = eth_stats_get,
 	.stats_reset = eth_stats_reset,
+	.mtu_set = eth_mtu_set,
 };
 
 static int
@@ -1233,6 +1270,7 @@ pmd_init_internals(struct rte_vdev_device *vdev,
 		.addr_bytes = { 0x02, 0x70, 0x63, 0x61, 0x70, iface_idx++ }
 	};
 	(*internals)->phy_mac = 0;
+	(*internals)->mtu = RTE_ETH_PCAP_SNAPLEN;
 	data = (*eth_dev)->data;
 	data->nb_rx_queues = (uint16_t)nb_rx_queues;
 	data->nb_tx_queues = (uint16_t)nb_tx_queues;
-- 
2.17.1