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

[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>
---
 doc/guides/nics/tap.rst       |  6 +++++
 drivers/net/tap/rte_eth_tap.c | 62 +++++++++++++++++++++++++++++++++++++++----
 2 files changed, 63 insertions(+), 5 deletions(-)

diff --git a/doc/guides/nics/tap.rst b/doc/guides/nics/tap.rst
index dc6f834..6b083c8 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 29d6356..3489b04 100644
--- a/drivers/net/tap/rte_eth_tap.c
+++ b/drivers/net/tap/rte_eth_tap.c
@@ -49,7 +49,14 @@
 #define ETH_TAP_MAC_ARG         "mac"
 #define ETH_TAP_MAC_FIXED       "fixed"
 
+#define ETH_TAP_MAC_STR_FXD     1
+#define ETH_TAP_MAC_STR_USR     2
+#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 unsigned char user_mac[ETHER_ADDR_LEN];
 
 static const char *valid_arguments[] = {
 	ETH_TAP_IFACE_ARG,
@@ -1397,13 +1404,20 @@ enum ioctl_mode {
 		pmd->txq[i].fd = -1;
 	}
 
-	if (fixed_mac_type) {
+	if (fixed_mac_type == ETH_TAP_MAC_STR_FXD) {
 		/* 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 (fixed_mac_type == ETH_TAP_MAC_STR_USR) {
+		RTE_LOG(INFO, PMD,
+			"%s; user MAC (%02x:%02x:%02x:%02x:%02x:%02x) argument\n",
+			pmd->name,
+			user_mac[0], user_mac[1], user_mac[2],
+			user_mac[3], user_mac[4], user_mac[5]);
+			rte_memcpy(&pmd->eth_addr, user_mac, ETHER_ADDR_LEN);
 	} else {
 		eth_random_addr((uint8_t *)&pmd->eth_addr);
 	}
@@ -1577,10 +1591,48 @@ enum ioctl_mode {
 	     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[20] = {0}, *mac_byte = NULL;
+	unsigned int index = 0;
+
+	if (!value)
+		return 0;
+
+	if (!strncasecmp(ETH_TAP_MAC_FIXED, value,
+			strlen(ETH_TAP_MAC_FIXED))) {
+		*(int *)extra_args = ETH_TAP_MAC_STR_FXD;
+		goto success;
+	}
+
+	if (strlen(value) == 17) {
+		strncpy(mac_temp, value, 18);
+		mac_temp[19] = '\0';
+		mac_byte = strtok(mac_temp, ":");
+
+		while ((mac_byte != NULL) &&
+				strspn(mac_byte, ETH_TAP_CMP_MAC_FMT) &&
+				strspn((mac_byte + 1), ETH_TAP_CMP_MAC_FMT) &&
+				strlen(mac_byte) == 2) {
+			user_mac[index] = strtoul(mac_byte, NULL, 16);
+			mac_byte = strtok(NULL, ":");
+			index += 1;
+		}
+
+		if (index != 6)
+			goto error;
+
+		*(int *)extra_args = ETH_TAP_MAC_STR_USR;
+	} else {
+		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.
@@ -1716,5 +1768,5 @@ enum ioctl_mode {
 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>");
-- 
1.9.1