[dpdk-dev] [PATCH] net/tap: add support for fixed mac addresses

Wiles, Keith keith.wiles at intel.com
Tue Apr 11 15:23:24 CEST 2017


> On Apr 11, 2017, at 2:18 AM, Pascal Mazon <pascal.mazon at 6wind.com> wrote:
> 
> Hi Keith,
> 
> I have a few comments on your patch, see inline.
> 
> On Mon, 10 Apr 2017 13:18:50 -0500
> Keith Wiles <keith.wiles at intel.com> wrote:
> 
>> Support for a fixed MAC address for testing with the last octet
>> incrementing by one for each interface defined with the new 'mac=fixed'
>> string on the --vdev option. The default option is still to randomize
>> the MAC address for each tap interface.
>> 
>> Signed-off-by: Keith Wiles <keith.wiles at intel.com>
>> ---
>> doc/guides/nics/tap.rst       | 13 +++++++++++-
>> drivers/net/tap/rte_eth_tap.c | 49 ++++++++++++++++++++++++++++++++++++++++---
>> 2 files changed, 58 insertions(+), 4 deletions(-)
>> 
>> diff --git a/doc/guides/nics/tap.rst b/doc/guides/nics/tap.rst
>> index 5c5ba5357..e3819836a 100644
>> --- a/doc/guides/nics/tap.rst
>> +++ b/doc/guides/nics/tap.rst
>> @@ -46,7 +46,7 @@ These TAP interfaces can be used with Wireshark or tcpdump or Pktgen-DPDK
>> along with being able to be used as a network connection to the DPDK
>> application. The method enable one or more interfaces is to use the
>> ``--vdev=net_tap0`` option on the DPDK application command line. Each
>> -``--vdev=net_tap1`` option give will create an interface named dtap0, dtap1,
>> +``--vdev=net_tap1`` option given will create an interface named dtap0, dtap1,
>> and so on.
>> 
>> The interface name can be changed by adding the ``iface=foo0``, for example::
>> @@ -58,6 +58,17 @@ needed, but the interface does not enforce that speed, for example::
>> 
>>    --vdev=net_tap0,iface=foo0,speed=25000
>> 
>> +Normally the PMD will generate random MAC address, but when testing or with
> 
> "random MAC" -> "a random MAC"
> 
>> +a static configurations the developer may need a fixed MAC address style.
> 
> "configurations" -> "configuration"
> 
>> +Using the option ``mac=fixed`` you can create a fixed known MAC address::
>> +
>> +   --vdev=net_tap0,mac=fixed
>> +
>> +The MAC address will be fixed value with the last octet incrementing by one
> 
> "be" -> "have a"
> 
>> +each time for each interface string containing ``mac=fixed``. The MAC address
> 
> "each time" -> ""
> 
>> +is formatted as 00:'d':'t':'a':'p':[00-FF] convert the characters to hex
> 
> " convert" -> ". Convert"
> 
>> +and you get ``00:64:74:61:70:[00-FF]``.
>> +
>> 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 347a80741..7a676c588 100644
>> --- a/drivers/net/tap/rte_eth_tap.c
>> +++ b/drivers/net/tap/rte_eth_tap.c
>> @@ -1,7 +1,7 @@
>> /*-
>>  *   BSD LICENSE
>>  *
>> - *   Copyright(c) 2016 Intel Corporation. All rights reserved.
>> + *   Copyright(c) 2017 Intel Corporation. All rights reserved.
> 
> Shouldn't it be "2016-2017"?
> 
>>  *   All rights reserved.
>>  *
>>  *   Redistribution and use in source and binary forms, with or without
>> @@ -71,6 +71,13 @@
>> #define ETH_TAP_IFACE_ARG       "iface"
>> #define ETH_TAP_SPEED_ARG       "speed"
>> #define ETH_TAP_REMOTE_ARG      "remote"
>> +#define ETH_TAP_MAC_ARG		"mac"
> 
> You used tabs instead of spaces.
> 
>> +
>> +#ifdef IFF_MULTI_QUEUE
>> +#define RTE_PMD_TAP_MAX_QUEUES	16
>> +#else
>> +#define RTE_PMD_TAP_MAX_QUEUES	1
>> +#endif
> 
> Remove this IFF_MULTI_QUEUE definition as it is done in rte_eth_tap.h now (needed for pmd_internals).

This should have been removed in your patch and now that Ferruh wants you to submit a patch for the string at the bottom of the PMD, can you remove it?

I can do both in my patch, but Ferruh and you need to agree before I can submit my patch.

> 
>> 
>> #define FLOWER_KERNEL_VERSION KERNEL_VERSION(4, 2, 0)
>> #define FLOWER_VLAN_KERNEL_VERSION KERNEL_VERSION(4, 9, 0)
>> @@ -81,10 +88,12 @@ static const char *valid_arguments[] = {
>> 	ETH_TAP_IFACE_ARG,
>> 	ETH_TAP_SPEED_ARG,
>> 	ETH_TAP_REMOTE_ARG,
>> +	ETH_TAP_MAC_ARG,
>> 	NULL
>> };
>> 
>> static int tap_unit;
>> +static int fixed_mac_type;
> 
> There is no need for a global variable, especially as the value should not be the same for each driver instance.
> Typically when one tap uses "mac=fixed" and the next one doesn't.
> More comments bellow for that.
> 
>> 
>> static volatile uint32_t tap_trigger;	/* Rx trigger */
>> 
>> @@ -1230,7 +1239,17 @@ eth_dev_tap_create(const char *name, char *tap_name, char *remote_iface)
>> 		rte_memcpy(&pmd->eth_addr, ifr.ifr_hwaddr.sa_data,
>> 			   ETHER_ADDR_LEN);
>> 	} else {
>> -		eth_random_addr((uint8_t *)&pmd->eth_addr);
>> +		if (fixed_mac_type) {
>> +			static int iface_idx;
>> +
>> +			pmd->eth_addr.addr_bytes[0] = 0x00;
>> +			pmd->eth_addr.addr_bytes[1] = 'd';
>> +			pmd->eth_addr.addr_bytes[2] = 't';
>> +			pmd->eth_addr.addr_bytes[3] = 'a';
>> +			pmd->eth_addr.addr_bytes[4] = 'p';
>> +			pmd->eth_addr.addr_bytes[5] = 0 + iface_idx++;
>> +		} else
>> +			eth_random_addr((uint8_t *)&pmd->eth_addr);
> 
> To avoid checkpatch warning, use else { }.

Ferruh, states this is OK and does not need to have the { } added. I will not add the { } here.

> 
>> 	}
>> 
>> 	return 0;
>> @@ -1285,6 +1304,16 @@ set_remote_iface(const char *key __rte_unused,
>> 	return 0;
>> }
>> 
>> +static int
>> +set_mac_type(const char *key __rte_unused, const char *value, void *extra_args)
>> +{
>> +	/* Assume random mac address */
>> +	*(int *)extra_args = 0;
> 
> With an automatic variable for fixed_mac_type in rte_pmd_tap_probe(), no need for setting it to 0 here.

It does need to be set of each instance of the call to this routine even if I remove the global. Each interface can have a different state.

> 
>> +	if (value && !strcasecmp("fixed", value))
> 
> I think a macro for "fixed" would be better. Maybe a ETH_TAP_MAC_FIXED "fixed" at the top?

I will use the already existing macro ETH_TAP_MAC_ARG instead.
> 
>> +		*(int *)extra_args = 1;
>> +	return 0;
>> +}
>> +
>> /* Open a TAP interface device.
>>  */
>> static int
>> @@ -1301,6 +1330,7 @@ rte_pmd_tap_probe(const char *name, const char *params)
>> 		 DEFAULT_TAP_NAME, tap_unit++);
>> 	memset(remote_iface, 0, RTE_ETH_NAME_MAX_LEN);
>> 
>> +	fixed_mac_type = 0;
> 
> Turn fixed_mac_type to an automatic variable, local to this function.
> And add the argument to eth_dev_tap_create().

Need to have the global to exist, because I need to be able to test the variable later. The variable could be placed in a allocated structure, but does it really matter to have a static variable here?

> 
>> 	if (params && (params[0] != '\0')) {
>> 		RTE_LOG(DEBUG, PMD, "paramaters (%s)\n", params);
>> 
>> @@ -1332,6 +1362,15 @@ rte_pmd_tap_probe(const char *name, const char *params)
>> 				if (ret == -1)
>> 					goto leave;
>> 			}
>> +
>> +			if (rte_kvargs_count(kvlist, ETH_TAP_MAC_ARG) == 1) {
>> +				ret = rte_kvargs_process(kvlist,
>> +							 ETH_TAP_MAC_ARG,
>> +							 &set_mac_type,
>> +							 &fixed_mac_type);
>> +				if (ret == -1)
>> +					goto leave;
>> +			}
>> 		}
>> 	}
>> 	pmd_link.link_speed = speed;
>> @@ -1394,4 +1433,8 @@ static struct rte_vdev_driver pmd_tap_drv = {
>> };
>> RTE_PMD_REGISTER_VDEV(net_tap, pmd_tap_drv);
>> RTE_PMD_REGISTER_ALIAS(net_tap, eth_tap);
>> -RTE_PMD_REGISTER_PARAM_STRING(net_tap, "iface=<string>,speed=N");
>> +RTE_PMD_REGISTER_PARAM_STRING(net_tap,
>> +			      "iface=<string>,"
>> +			      "speed=N,"
>> +			      "remote=<string>,"
>> +			      "mac=fixed");
> 
> Indeed, I forgot to update that when I introduced the remote!
> 
> That's it for me,
> Thank you.
> 
> Pascal

Regards,
Keith



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