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

["Xing, Beilei" <beilei.xing@intel.com>]

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.

> 
> <...>
> 
> > +
> > +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.

> 
> > +{
> > +	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.

> 
> > +				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?

> 
> > +
> > +			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

> 
> <...>
>