netdev - Re: [patch net-next v2 06/12] net: mroute: Check if rule is a default rule

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Date:   Mon, 25 Sep 2017 13:02:17 +0300
From:   Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
To:     Jiri Pirko <jiri@...nulli.us>,
        Yunsheng Lin <linyunsheng@...wei.com>
Cc:     netdev@...r.kernel.org, davem@...emloft.net, yotamg@...lanox.com,
        idosch@...lanox.com, mlxsw@...lanox.com, andrew@...n.ch
Subject: Re: [patch net-next v2 06/12] net: mroute: Check if rule is a default
 rule

On 25/09/17 12:45, Jiri Pirko wrote:
> Mon, Sep 25, 2017 at 03:28:21AM CEST, linyunsheng@...wei.com wrote:
>> Hi, Jiri
>>
>> On 2017/9/25 1:22, Jiri Pirko wrote:
>>> From: Yotam Gigi <yotamg@...lanox.com>
>>>
>>> When the ipmr starts, it adds one default FIB rule that matches all packets
>>> and sends them to the DEFAULT (multicast) FIB table. A more complex rule
>>> can be added by user to specify that for a specific interface, a packet
>>> should be look up at either an arbitrary table or according to the l3mdev
>>> of the interface.
>>>
>>> For drivers willing to offload the ipmr logic into a hardware but don't
>>> want to offload all the FIB rules functionality, provide a function that
>>> can indicate whether the FIB rule is the default multicast rule, thus only
>>> one routing table is needed.
>>>
>>> This way, a driver can register to the FIB notification chain, get
>>> notifications about FIB rules added and trigger some kind of an internal
>>> abort mechanism when a non default rule is added by the user.
>>>
>>> Signed-off-by: Yotam Gigi <yotamg@...lanox.com>
>>> Reviewed-by: Ido Schimmel <idosch@...lanox.com>
>>> Signed-off-by: Jiri Pirko <jiri@...lanox.com>
>>> ---
>>>  include/linux/mroute.h |  7 +++++++
>>>  net/ipv4/ipmr.c        | 10 ++++++++++
>>>  2 files changed, 17 insertions(+)
>>>
>>> diff --git a/include/linux/mroute.h b/include/linux/mroute.h
>>> index 5566580..b072a84 100644
>>> --- a/include/linux/mroute.h
>>> +++ b/include/linux/mroute.h
>>> @@ -5,6 +5,7 @@
>>>  #include <linux/pim.h>
>>>  #include <linux/rhashtable.h>
>>>  #include <net/sock.h>
>>> +#include <net/fib_rules.h>
>>>  #include <net/fib_notifier.h>
>>>  #include <uapi/linux/mroute.h>
>>>  
>>> @@ -19,6 +20,7 @@ int ip_mroute_getsockopt(struct sock *, int, char __user *, int __user *);
>>>  int ipmr_ioctl(struct sock *sk, int cmd, void __user *arg);
>>>  int ipmr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
>>>  int ip_mr_init(void);
>>> +bool ipmr_rule_default(const struct fib_rule *rule);
>>>  #else
>>>  static inline int ip_mroute_setsockopt(struct sock *sock, int optname,
>>>  				       char __user *optval, unsigned int optlen)
>>> @@ -46,6 +48,11 @@ static inline int ip_mroute_opt(int opt)
>>>  {
>>>  	return 0;
>>>  }
>>> +
>>> +static inline bool ipmr_rule_default(const struct fib_rule *rule)
>>> +{
>>> +	return true;
>>> +}
>>>  #endif
>>>  
>>>  struct vif_device {
>>> diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
>>> index 2a795d2..a714f55 100644
>>> --- a/net/ipv4/ipmr.c
>>> +++ b/net/ipv4/ipmr.c
>>> @@ -320,6 +320,16 @@ static unsigned int ipmr_rules_seq_read(struct net *net)
>>>  }
>>>  #endif
>>>  
>>> +bool ipmr_rule_default(const struct fib_rule *rule)
>>> +{
>>> +#if IS_ENABLED(CONFIG_FIB_RULES)
>>> +	return fib_rule_matchall(rule) && rule->table == RT_TABLE_DEFAULT;
>>> +#else
>>> +	return true;
>>> +#endif
>>
>> In patch 02, You have the following, can you do the same for the above?
>> +#ifdef CONFIG_IP_MROUTE
>> +void ipmr_cache_free(struct mfc_cache *mfc_cache);
>> +#else
>> +static inline void ipmr_cache_free(struct mfc_cache *mfc_cache)
>> +{
>> +}
>> +#endif
> 
> I don't believe this is necessary. The solution you described is often
> used in headers. But here, I'm ok with the current code.
> 

+1

> 
>>
>>> +}
>>> +EXPORT_SYMBOL(ipmr_rule_default);
>>> +
>>>  static inline int ipmr_hash_cmp(struct rhashtable_compare_arg *arg,
>>>  				const void *ptr)
>>>  {
>>>
>>