[dpdk-dev] [PATCH v2] net/tap: allow user MAC to be passed as args

[Pascal Mazon <pascal.mazon@6wind.com>]

From: Vipin Varghese <vipin.varghese@intel.com>

Allow TAP PMD to pass user desired MAC address as argument.
The argument value is processed as string, where each 2 bytes
are converted to HEX MAC address after validation.

Signed-off-by: Vipin Varghese <vipin.varghese@intel.com>
Signed-off-by: Pascal Mazon <pascal.mazon@6wind.com>
---

Hi Vipin,

I suggest the following patch for your MAC address argument, if that
suits you.
I removed ETH_TAP_MAC_STR_FXD and ETH_TAP_MAC_STR_USR that were not
really useful. I find it nicer to deal with MAC mostly inside
set_mac_type().
What do you think? Can you test that it fits your needs?

Best regards,
Pascal

 doc/guides/nics/tap.rst       |  6 ++++
 drivers/net/tap/rte_eth_tap.c | 80 +++++++++++++++++++++++++++++--------------
 2 files changed, 60 insertions(+), 26 deletions(-)

diff --git a/doc/guides/nics/tap.rst b/doc/guides/nics/tap.rst
index dc6f834ca0a1..6b083c846b21 100644
--- a/doc/guides/nics/tap.rst
+++ b/doc/guides/nics/tap.rst
@@ -69,6 +69,12 @@ for each interface string containing ``mac=fixed``. The MAC address is formatted
 as 00:'d':'t':'a':'p':[00-FF]. Convert the characters to hex and you get the
 actual MAC address: ``00:64:74:61:70:[00-FF]``.
 
+   --vdev=net_tap0,mac="00:64:74:61:70:11"
+
+The MAC address will have a user value passed as string. The MAC address is in
+format with delimeter ``:``. The string is byte converted to hex and you get
+the actual MAC address: ``00:64:74:61:70:11``.
+
 It is possible to specify a remote netdevice to capture packets from by adding
 ``remote=foo1``, for example::
 
diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
index 29d635613c0b..d9e5ec92b8f0 100644
--- a/drivers/net/tap/rte_eth_tap.c
+++ b/drivers/net/tap/rte_eth_tap.c
@@ -49,6 +49,10 @@
 #define ETH_TAP_MAC_ARG         "mac"
 #define ETH_TAP_MAC_FIXED       "fixed"
 
+#define ETH_TAP_USR_MAC_FMT     "xx:xx:xx:xx:xx:xx"
+#define ETH_TAP_CMP_MAC_FMT     "0123456789ABCDEFabcdef"
+#define ETH_TAP_MAC_ARG_FMT     "["ETH_TAP_MAC_FIXED "|" ETH_TAP_USR_MAC_FMT"]"
+
 static struct rte_vdev_driver pmd_tap_drv;
 
 static const char *valid_arguments[] = {
@@ -278,15 +282,8 @@ tap_rx_offload_get_queue_capa(void)
 static bool
 tap_rxq_are_offloads_valid(struct rte_eth_dev *dev, uint64_t offloads)
 {
-	uint64_t port_offloads = dev->data->dev_conf.rxmode.offloads;
-	uint64_t queue_supp_offloads = tap_rx_offload_get_queue_capa();
-	uint64_t port_supp_offloads = tap_rx_offload_get_port_capa();
-
-	if ((offloads & (queue_supp_offloads | port_supp_offloads)) !=
-	    offloads)
-		return false;
-	if ((port_offloads ^ offloads) & port_supp_offloads)
-		return false;
+	(void)dev;
+	(void)offloads;
 	return true;
 }
 
@@ -1335,7 +1332,7 @@ static const struct eth_dev_ops ops = {
 
 static int
 eth_dev_tap_create(struct rte_vdev_device *vdev, char *tap_name,
-		   char *remote_iface, int fixed_mac_type)
+		   char *remote_iface, struct ether_addr *mac_addr)
 {
 	int numa_node = rte_socket_id();
 	struct rte_eth_dev *dev;
@@ -1397,16 +1394,10 @@ eth_dev_tap_create(struct rte_vdev_device *vdev, char *tap_name,
 		pmd->txq[i].fd = -1;
 	}
 
-	if (fixed_mac_type) {
-		/* fixed mac = 00:64:74:61:70:<iface_idx> */
-		static int iface_idx;
-		char mac[ETHER_ADDR_LEN] = "\0dtap";
-
-		mac[ETHER_ADDR_LEN - 1] = iface_idx++;
-		rte_memcpy(&pmd->eth_addr, mac, ETHER_ADDR_LEN);
-	} else {
+	if (is_zero_ether_addr(mac_addr))
 		eth_random_addr((uint8_t *)&pmd->eth_addr);
-	}
+	else
+		rte_memcpy(&pmd->eth_addr, mac_addr, sizeof(mac_addr));
 
 	/* Immediately create the netdevice (this will create the 1st queue). */
 	/* rx queue */
@@ -1577,10 +1568,47 @@ set_mac_type(const char *key __rte_unused,
 	     const char *value,
 	     void *extra_args)
 {
-	if (value &&
-	    !strncasecmp(ETH_TAP_MAC_FIXED, value, strlen(ETH_TAP_MAC_FIXED)))
-		*(int *)extra_args = 1;
+	char mac_temp[strlen(ETH_TAP_USR_MAC_FMT) + 1], *mac_byte = NULL;
+	struct ether_addr *user_mac = extra_args;
+	unsigned int index = 0;
+
+	if (!value)
+		return 0;
+
+	if (!strncasecmp(ETH_TAP_MAC_FIXED, value,
+			strlen(ETH_TAP_MAC_FIXED))) {
+		static int iface_idx;
+
+		/* fixed mac = 00:64:74:61:70:<iface_idx> */
+		memcpy((char *)user_mac->addr_bytes, "\0dtap", ETHER_ADDR_LEN);
+		user_mac->addr_bytes[ETHER_ADDR_LEN - 1] = iface_idx++ + '0';
+		goto success;
+	}
+
+	if (strlen(value) != strlen(ETH_TAP_USR_MAC_FMT))
+		goto error;
+
+	snprintf(mac_temp, sizeof(mac_temp), "%s", value);
+	mac_byte = strtok(mac_temp, ":");
+
+	while ((mac_byte != NULL) &&
+			strspn(mac_byte, ETH_TAP_CMP_MAC_FMT) &&
+			strlen(mac_byte) == 2) {
+		user_mac->addr_bytes[index++] = (char) strtoul(mac_byte, NULL, 16);
+		mac_byte = strtok(NULL, ":");
+	}
+
+	if (index != 6)
+		goto error;
+
+success:
+	RTE_LOG(DEBUG, PMD, "TAP user MAC param (%s)\n", value);
 	return 0;
+
+error:
+	RTE_LOG(ERR, PMD, "TAP user MAC (%s) is not in format (%s|%s)\n",
+		value, ETH_TAP_MAC_FIXED, ETH_TAP_USR_MAC_FMT);
+	return -1;
 }
 
 /* Open a TAP interface device.
@@ -1594,7 +1622,7 @@ rte_pmd_tap_probe(struct rte_vdev_device *dev)
 	int speed;
 	char tap_name[RTE_ETH_NAME_MAX_LEN];
 	char remote_iface[RTE_ETH_NAME_MAX_LEN];
-	int fixed_mac_type = 0;
+	struct ether_addr user_mac = {0};
 
 	name = rte_vdev_device_name(dev);
 	params = rte_vdev_device_args(dev);
@@ -1640,7 +1668,7 @@ rte_pmd_tap_probe(struct rte_vdev_device *dev)
 				ret = rte_kvargs_process(kvlist,
 							 ETH_TAP_MAC_ARG,
 							 &set_mac_type,
-							 &fixed_mac_type);
+							 &user_mac);
 				if (ret == -1)
 					goto leave;
 			}
@@ -1651,7 +1679,7 @@ rte_pmd_tap_probe(struct rte_vdev_device *dev)
 	RTE_LOG(NOTICE, PMD, "Initializing pmd_tap for %s as %s\n",
 		name, tap_name);
 
-	ret = eth_dev_tap_create(dev, tap_name, remote_iface, fixed_mac_type);
+	ret = eth_dev_tap_create(dev, tap_name, remote_iface, &user_mac);
 
 leave:
 	if (ret == -1) {
@@ -1716,5 +1744,5 @@ RTE_PMD_REGISTER_ALIAS(net_tap, eth_tap);
 RTE_PMD_REGISTER_PARAM_STRING(net_tap,
 			      ETH_TAP_IFACE_ARG "=<string> "
 			      ETH_TAP_SPEED_ARG "=<int> "
-			      ETH_TAP_MAC_ARG "=" ETH_TAP_MAC_FIXED " "
+			      ETH_TAP_MAC_ARG "=" ETH_TAP_MAC_ARG_FMT
 			      ETH_TAP_REMOTE_ARG "=<string>");
-- 
2.11.0