Re: [PATCH v5 07/17] net/i40e: add flow validate function

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 1/5/2017 6:08 AM, Xing, Beilei wrote:
> Hi Ferruh,
> 
>> -----Original Message-----
>> From: Yigit, Ferruh
>> Sent: Thursday, January 5, 2017 2:57 AM
>> To: Xing, Beilei <beilei.xing@intel.com>; Wu, Jingjing
>> <jingjing.wu@intel.com>; Zhang, Helin <helin.zhang@intel.com>
>> Cc: dev@dpdk.org
>> Subject: Re: [dpdk-dev] [PATCH v5 07/17] net/i40e: add flow validate
>> function
>>
>> On 1/4/2017 3:22 AM, Beilei Xing wrote:
>>> This patch adds i40e_flow_validation function to check if a flow is
>>> valid according to the flow pattern.
>>> i40e_parse_ethertype_filter is added first, it also gets the ethertype
>>> info.
>>> i40e_flow.c is added to handle all generic filter events.
>>>
>>> Signed-off-by: Beilei Xing <beilei.xing@intel.com>
>>> ---
>>
>> <...>
>>
>>> diff --git a/drivers/net/i40e/i40e_ethdev.c
>>> b/drivers/net/i40e/i40e_ethdev.c index 153322a..edfd52b 100644
>>> --- a/drivers/net/i40e/i40e_ethdev.c
>>> +++ b/drivers/net/i40e/i40e_ethdev.c
>>> @@ -8426,6 +8426,8 @@ i40e_ethertype_filter_handle(struct rte_eth_dev
>> *dev,
>>>  	return ret;
>>>  }
>>>
>>> +const struct rte_flow_ops i40e_flow_ops;
>>
>> Is this intentional (instead of using extern) ?
>> Because i40e_flow.c has a global variable definition with same name, it looks
>> like this is not causing a build error, but I think confusing.
>>
> 
> Actually it's the global variable definition in i40e_flow.c.  I thought gcc would add extern automatically during compiling, as I checked the address of the variable is the same in different files.
> To avoid confusion, I will add extern in next version.
> 
>> <...>
>>
>>> +static int i40e_parse_ethertype_act(struct rte_eth_dev *dev,
>>> +				    const struct rte_flow_action *actions,
>>> +				    struct rte_flow_error *error,
>>> +				    struct rte_eth_ethertype_filter *filter);
>>
>> In API naming, I would prefer full "action" instead of shorten "act", but it is
>> your call.
> 
> I will change the API name in next version. Thanks.
> 
>>
>> <...>
>>
>>> +
>>> +union i40e_filter_t cons_filter;
>>
>> Why this cons_filter is required. I can see this is saving some state related
>> rule during validate function.
>> If the plan is to use this during rule creation, is user has to call validate before
>> each create?
> 
> You are right, cons_filter will get filter info during validation, and it's for flow_create function.
> User needn't to call the flow_validate function, as validate function will be called in i40e_flow_create.

Ok then.

> 
>>
>> <...>
>>
>>> +
>>> +static int
>>> +i40e_parse_ethertype_filter(struct rte_eth_dev *dev,
>>> +			    const struct rte_flow_attr *attr,
>>> +			    const struct rte_flow_item pattern[],
>>> +			    const struct rte_flow_action actions[],
>>> +			    struct rte_flow_error *error,
>>> +			    union i40e_filter_t *filter)
>>> +{
>>> +	struct rte_eth_ethertype_filter *ethertype_filter =
>>> +		&filter->ethertype_filter;
>>> +	int ret;
>>> +
>>> +	ret = i40e_parse_ethertype_pattern(dev, pattern, error,
>>> +					   ethertype_filter);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	ret = i40e_parse_ethertype_act(dev, actions, error,
>>> +				       ethertype_filter);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	ret = i40e_parse_attr(attr, error);
>>
>> It is your call, but I would suggest using a specific namespace for all rte_flow
>> related functions, something like "i40e_flow_".
>> In this context it is clear what this function is, but in whole driver code, the
>> function name is too generic to understand what it does.
> 
> Make sense. I'll update the function names.
> 
>>
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	return ret;
>>> +}
>>> +
>>
>> <...>
>>
>>> +
>>> +static int
>>> +i40e_parse_ethertype_pattern(__rte_unused struct rte_eth_dev *dev,
>>> +			     const struct rte_flow_item *pattern,
>>> +			     struct rte_flow_error *error,
>>> +			     struct rte_eth_ethertype_filter *filter)
>>
>> I think it is good idea to comment what pattern is recognized in to function
>> comment, instead of reading code every time to figure out.
> 
> In fact, the array of i40e_supported_patterns has listed all supported patterns for each filter type.
> i40e_supported_patterns is also defined in this patch.

i40e_supported_patterns only shows item->type values, I think it is good
to documents expected/valid mask (.dst, .src, .type) and last values for
this type.

> 
>>
>>> +{
>>> +	const struct rte_flow_item *item = pattern;
>>> +	const struct rte_flow_item_eth *eth_spec;
>>> +	const struct rte_flow_item_eth *eth_mask;
>>> +	enum rte_flow_item_type item_type;
>>> +
>>> +	for (; item->type != RTE_FLOW_ITEM_TYPE_END; item++) {
>>> +		if (item->last) {
>>> +			rte_flow_error_set(error, EINVAL,
>>> +					   RTE_FLOW_ERROR_TYPE_ITEM,
>>> +					   item,
>>> +					   "Not support range");
>>> +			return -rte_errno;
>>> +		}
>>> +		item_type = item->type;
>>> +		switch (item_type) {
>>> +		case RTE_FLOW_ITEM_TYPE_ETH:
>>> +			eth_spec = (const struct rte_flow_item_eth *)item-
>>> spec;
>>> +			eth_mask = (const struct rte_flow_item_eth *)item-
>>> mask;
>>> +			/* Get the MAC info. */
>>> +			if (!eth_spec || !eth_mask) {
>>
>> Why an eth_mask is required?
> Yes, since eth_type mask in eth_mask  should be UINT16_MAX. 
> 
>> Can't driver support drop/queue packets from specific src to specific dst with
>> specific eth_type?
> No,  we support specific dst with specific eth_type, or only specific eth_type. Perfect match.

Thanks for clarification.

> 
>>
>>> +				rte_flow_error_set(error, EINVAL,
>>> +
>> RTE_FLOW_ERROR_TYPE_ITEM,
>>> +						   item,
>>> +						   "NULL ETH spec/mask");
>>> +				return -rte_errno;
>>> +			}
>>> +
>>> +			/* Mask bits of source MAC address must be full of 0.
>>> +			 * Mask bits of destination MAC address must be full
>>> +			 * of 1 or full of 0.
>>> +			 */
>>> +			if (!is_zero_ether_addr(&eth_mask->src) ||
>>> +			    (!is_zero_ether_addr(&eth_mask->dst) &&
>>> +			     !is_broadcast_ether_addr(&eth_mask->dst))) {
>>> +				rte_flow_error_set(error, EINVAL,
>>> +
>> RTE_FLOW_ERROR_TYPE_ITEM,
>>> +						   item,
>>> +						   "Invalid MAC_addr mask");
>>> +				return -rte_errno;
>>> +			}
>>> +
>>> +			if ((eth_mask->type & UINT16_MAX) !=
>> UINT16_MAX) {
>>> +				rte_flow_error_set(error, EINVAL,
>>> +
>> RTE_FLOW_ERROR_TYPE_ITEM,
>>> +						   item,
>>> +						   "Invalid ethertype mask");
>>
>> Why returning error here?
>> Can't we say drop packets to specific MAC address, independent from the
>> ether_type?
> 
> No. as I said above, we support specific dst with specific eth_type, or only specific eth_type for ethertype_filter.
> 
>>
>>> +				return -rte_errno;
>>> +			}
>>> +
>>> +			/* If mask bits of destination MAC address
>>> +			 * are full of 1, set RTE_ETHTYPE_FLAGS_MAC.
>>> +			 */
>>> +			if (is_broadcast_ether_addr(&eth_mask->dst)) {
>>> +				filter->mac_addr = eth_spec->dst;
>>> +				filter->flags |= RTE_ETHTYPE_FLAGS_MAC;
>>> +			} else {
>>> +				filter->flags &= ~RTE_ETHTYPE_FLAGS_MAC;
>>> +			}
>>> +			filter->ether_type = rte_be_to_cpu_16(eth_spec-
>>> type);
>>> +
>>> +			if (filter->ether_type == ETHER_TYPE_IPv4 ||
>>> +			    filter->ether_type == ETHER_TYPE_IPv6) {
>>> +				rte_flow_error_set(error, EINVAL,
>>> +
>> RTE_FLOW_ERROR_TYPE_ITEM,
>>> +						   item,
>>> +						   "Unsupported ether_type
>> in"
>>> +						   " control packet filter.");
>>
>> Can't we create a drop rule based on dst MAC address if eth_type is ip ?
> 
> No, we don't support drop MAC_addr + eth_type_IP for ethertype filter.
> 
>>
>>> +				return -rte_errno;
>>> +			}
>>> +			if (filter->ether_type == ETHER_TYPE_VLAN)
>>> +				PMD_DRV_LOG(WARNING, "filter vlan
>> ether_type in"
>>> +					    " first tag is not supported.");
>>
>> Who is the target of this message?
>> To the caller, this API is responding as this is supported.
>> The end user, the user of the application, can see this message, how this
>> message will help to end user?
> 
> Actually I add this warning according to the original processing in i40e_dev_eythertype_filter_set. 
> After checing datasheet, "The ethertype programmed by this command should not be one of the L2 tags ethertype (VLAN, E-tag, S-tag, etc.) and should not be IP or IPv6" is descripted.
> But if QinQ is disabled, and inner vlan is ETHER_TYPE_VLAN, the filter works. So the message is "vlan ether_type in outer tag is not supported".
> I want to simplify it in next version, don't support the situation above, and return error if (filter->ether_type == ETHER_TYPE_VLAN), because HW only recognizes ETH when QinQ is diabled. What do you think?

I think it is better.
And this can be fine tuned in the future to check QinQ and return
accordingly.

> 
>>
>>> +
>>> +			break;
>>> +		default:
>>> +			break;
>>> +		}
>>> +	}
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int
>>> +i40e_parse_ethertype_act(struct rte_eth_dev *dev,
>>> +			 const struct rte_flow_action *actions,
>>> +			 struct rte_flow_error *error,
>>> +			 struct rte_eth_ethertype_filter *filter)
>>
>> I think it would be good to comment this functions to say only DROP and
>> QUEUE actions are supported.
> 
> Yes, will update in next version.
> 
>>
>> <...>
>>
>>> +
>>> +static int
>>> +i40e_flow_validate(struct rte_eth_dev *dev,
>>> +		   const struct rte_flow_attr *attr,
>>> +		   const struct rte_flow_item pattern[],
>>> +		   const struct rte_flow_action actions[],
>>> +		   struct rte_flow_error *error)
>>> +{
>>> +	struct rte_flow_item *items; /* internal pattern w/o VOID items */
>>> +	parse_filter_t parse_filter;
>>> +	uint32_t item_num = 0; /* non-void item number of pattern*/
>>> +	uint32_t i = 0;
>>> +	int ret;
>>> +
>>> +	if (!pattern) {
>>> +		rte_flow_error_set(error, EINVAL,
>> RTE_FLOW_ERROR_TYPE_ITEM_NUM,
>>> +				   NULL, "NULL pattern.");
>>> +		return -rte_errno;
>>> +	}
>>> +
>>> +	if (!actions) {
>>> +		rte_flow_error_set(error, EINVAL,
>>> +				   RTE_FLOW_ERROR_TYPE_ACTION_NUM,
>>> +				   NULL, "NULL action.");
>>> +		return -rte_errno;
>>> +	}
>>
>> It may be good to validate attr too, if it is NULL or not. It is accessed without
>> check in later stages of the call stack.
> 
> Yes. Thanks for reminder.
> 
> Best Regards,
> Beilei
> 
>>
>> <...>
>>
>