[Intel-wired-lan] [PATCH 1/6] [net-next]net: sched: act_mirred: Extend redirect action to accept a traffic class

[Nambiar, Amritha]

On 8/1/2017 3:44 AM, Jamal Hadi Salim wrote:
> On 17-07-31 08:37 PM, Amritha Nambiar wrote:
>> The Mirred/redirect action is extended to forward to a traffic
>> class on the device. The traffic class index needs to be
>> provided in addition to the device's ifindex.
>>
>> Example:
>> # tc filter add dev eth0 protocol ip parent ffff: prio 1 flower\
>>    dst_ip 192.168.1.1/32 ip_proto udp dst_port 22\
>>    skip_sw indev eth0 action mirred ingress redirect dev eth0 tc 1
>>
>> Signed-off-by: Amritha Nambiar <amritha.nambiar at intel.com>
>> ---
>>   include/net/tc_act/tc_mirred.h        |    7 +++++++
>>   include/uapi/linux/tc_act/tc_mirred.h |    5 +++++
>>   net/sched/act_mirred.c                |   17 +++++++++++++++++
>>   3 files changed, 29 insertions(+)
>>
>> diff --git a/include/net/tc_act/tc_mirred.h b/include/net/tc_act/tc_mirred.h
>> index 604bc31..60058c4 100644
>> --- a/include/net/tc_act/tc_mirred.h
>> +++ b/include/net/tc_act/tc_mirred.h
>> @@ -9,6 +9,8 @@ struct tcf_mirred {
>>   	int			tcfm_eaction;
>>   	int			tcfm_ifindex;
>>   	bool			tcfm_mac_header_xmit;
>> +	u8			tcfm_tc;
>> +	u32			flags;
>>   	struct net_device __rcu	*tcfm_dev;
>>   	struct list_head	tcfm_list;
>>   };
>> @@ -37,4 +39,9 @@ static inline int tcf_mirred_ifindex(const struct tc_action *a)
>>   	return to_mirred(a)->tcfm_ifindex;
>>   }
>>   
>> +static inline int tcf_mirred_tc(const struct tc_action *a)
>> +{
>> +	return to_mirred(a)->tcfm_tc;
>> +}
>> +
>>   #endif /* __NET_TC_MIR_H */
>> diff --git a/include/uapi/linux/tc_act/tc_mirred.h b/include/uapi/linux/tc_act/tc_mirred.h
>> index 3d7a2b3..8ff4d76 100644
>> --- a/include/uapi/linux/tc_act/tc_mirred.h
>> +++ b/include/uapi/linux/tc_act/tc_mirred.h
>> @@ -9,6 +9,10 @@
>>   #define TCA_EGRESS_MIRROR 2 /* mirror packet to EGRESS */
>>   #define TCA_INGRESS_REDIR 3  /* packet redirect to INGRESS*/
>>   #define TCA_INGRESS_MIRROR 4 /* mirror packet to INGRESS */
>> +
>> +#define MIRRED_F_TC_MAP		0x1
>> +#define MIRRED_TC_MAP_MAX	0x10
>> +#define MIRRED_TC_MAP_MASK	0xF
>>                                                                                   
>>   struct tc_mirred {
>>   	tc_gen;
>> @@ -21,6 +25,7 @@ enum {
>>   	TCA_MIRRED_TM,
>>   	TCA_MIRRED_PARMS,
>>   	TCA_MIRRED_PAD,
>> +	TCA_MIRRED_TC_MAP,
>>   	__TCA_MIRRED_MAX
>>   };
>>   #define TCA_MIRRED_MAX (__TCA_MIRRED_MAX - 1)
>> diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
>> index 1b5549a..f9801de 100644
>> --- a/net/sched/act_mirred.c
>> +++ b/net/sched/act_mirred.c
>> @@ -67,6 +67,7 @@ static void tcf_mirred_release(struct tc_action *a, int bind)
>>   
>>   static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
>>   	[TCA_MIRRED_PARMS]	= { .len = sizeof(struct tc_mirred) },
>> +	[TCA_MIRRED_TC_MAP]	= { .type = NLA_U8 },
>>   };
>>   
>>   static unsigned int mirred_net_id;
>> @@ -83,6 +84,8 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
>>   	struct tcf_mirred *m;
>>   	struct net_device *dev;
>>   	bool exists = false;
>> +	u8 *tc_map = NULL;
>> +	u32 flags = 0;
>>   	int ret;
>>   
>>   	if (nla == NULL)
>> @@ -92,6 +95,14 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
>>   		return ret;
>>   	if (tb[TCA_MIRRED_PARMS] == NULL)
>>   		return -EINVAL;
>> +
>> +	if (tb[TCA_MIRRED_TC_MAP]) {
>> +		tc_map = nla_data(tb[TCA_MIRRED_TC_MAP]);
>> +		if (*tc_map >= MIRRED_TC_MAP_MAX)
>> +			return -EINVAL;
>> +		flags |= MIRRED_F_TC_MAP;
> 
> 
>> +	}
>> +
>>   	parm = nla_data(tb[TCA_MIRRED_PARMS]);
>>   
>>   	exists = tcf_hash_check(tn, parm->index, a, bind);
>> @@ -139,6 +150,7 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
>>   	ASSERT_RTNL();
>>   	m->tcf_action = parm->action;
>>   	m->tcfm_eaction = parm->eaction;
>> +	m->flags = flags;
>>   	if (dev != NULL) {
>>   		m->tcfm_ifindex = parm->ifindex;
>>   		if (ret != ACT_P_CREATED)
>> @@ -146,6 +158,8 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
>>   		dev_hold(dev);
>>   		rcu_assign_pointer(m->tcfm_dev, dev);
>>   		m->tcfm_mac_header_xmit = mac_header_xmit;
>> +		if (flags & MIRRED_F_TC_MAP)
>> +			m->tcfm_tc = *tc_map & MIRRED_TC_MAP_MASK;
>>   	}
>>   
> Is the mask a hardware limit. I dont know how these queues are
> allocated - I am assuming each of these "tc queues" maps to a rx
> DMA ring?

This is the bitmask for TC max range again defined in linux/netdevice.h.
I'll fix this to remove the new definition I have (MIRRED_TC_MAP_MASK)
here and replace with the existing TC_BITMASK. These are just the
traffic class index that are offloaded to the device. I had submitted
another series that handles configuring queues for the traffic classes
and queue layout offloaded via the mqprio framework.

> 
>>   	if (ret == ACT_P_CREATED) {
>> @@ -259,6 +273,9 @@ static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind,
>>   
>>   	if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
>>   		goto nla_put_failure;
>> +	if ((m->flags & MIRRED_F_TC_MAP) &&
>> +	    nla_put_u8(skb, TCA_MIRRED_TC_MAP, m->tcfm_tc))
>> +		goto nla_put_failure;
>>
> 
> If you have m->tcfm_tc then I dont think you need the flags; so i would
> remove it from the struct altogether.

I think I would still need the flags as "tc" index is an optional
parameter and the value zero is also a valid TC index. I was also
planning to use this flag to address Jiri's comment to fail this rule in
devices not supporting this offload.

> 
> cheers,
> jamal
>