Re: [PATCH nf-next v2 3/3] netfilter: nf_tables_offload: clean offload things when the device unregister

[wenxu <wenxu@ucloud.cn>]

On 9/5/2019 3:40 AM, Pablo Neira Ayuso wrote:
> Thanks for working on this.
>
> On Wed, Sep 04, 2019 at 03:07:31PM +0800, wenxu@ucloud.cn wrote:
>> diff --git a/net/netfilter/nf_tables_offload.c b/net/netfilter/nf_tables_offload.c
>> index 9657001..9fa3bdb 100644
>> --- a/net/netfilter/nf_tables_offload.c
>> +++ b/net/netfilter/nf_tables_offload.c
>> @@ -396,17 +396,78 @@ static void nft_indr_block_cb(struct net_device *dev,
>>  	mutex_unlock(&net->nft.commit_mutex);
>>  }
>>  
>> +static void nft_offload_chain_clean(struct nft_chain *chain)
>> +{
>> +	struct nft_rule *rule;
>> +
>> +	list_for_each_entry(rule, &chain->rules, list) {
>> +		nft_flow_offload_rule(chain, rule,
>> +				      NULL, FLOW_CLS_DESTROY);
>> +	}
>> +
>> +	nft_flow_offload_chain(chain, FLOW_BLOCK_UNBIND);
>> +}
>> +
>> +static int nft_offload_netdev_event(struct notifier_block *this,
>> +				    unsigned long event, void *ptr)
>> +{
>> +	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
>> +	struct nft_base_chain *basechain;
>> +	struct net *net = dev_net(dev);
>> +	struct nft_table *table;
>> +	struct nft_chain *chain;
>> +
>> +	if (event != NETDEV_UNREGISTER)
>> +		return NOTIFY_DONE;
>> +
>> +	mutex_lock(&net->nft.commit_mutex);
>> +	list_for_each_entry(table, &net->nft.tables, list) {
>> +		if (table->family != NFPROTO_NETDEV)
>> +			continue;
>> +
>> +		list_for_each_entry(chain, &table->chains, list) {
>> +			if (!nft_is_base_chain(chain) ||
>> +			    !(chain->flags & NFT_CHAIN_HW_OFFLOAD))
>> +				continue;
>> +
>> +			basechain = nft_base_chain(chain);
>> +			if (strncmp(basechain->dev_name, dev->name, IFNAMSIZ))
>> +				continue;
>> +
>> +			nft_offload_chain_clean(chain);
>> +			mutex_unlock(&net->nft.commit_mutex);
>> +			return NOTIFY_DONE;
>> +		}
>> +	}
>> +	mutex_unlock(&net->nft.commit_mutex);
> This code around the mutex look very similar to nft_block_indr_cb(),
> could you consolidate this? Probably something like
> nft_offload_netdev_iterate() and add a callback.

nft_offload_netdev_iterate is a good idear, But maybe it can't provide
a common callback. The nft_offload_netdev_iterate(without mutex) can return the chain
amke each function(with mutex) use it  

>
>> +	return NOTIFY_DONE;
>> +}
>> +
>>  static struct flow_indr_block_ing_entry block_ing_entry = {
>>  	.cb	= nft_indr_block_cb,
>>  	.list	= LIST_HEAD_INIT(block_ing_entry.list),
>>  };
>>  
>> -void nft_offload_init(void)
>> +static struct notifier_block nft_offload_netdev_notifier = {
>> +	.notifier_call	= nft_offload_netdev_event,
> No need for priority because of registration order, right?
yes,  nft_offload_init will early than nft_chain_filter mod init
>