Subject: Re: [PATCH net-next,v3 09/12] flow_dissector: add basic ethtool_rx_flow_spec to flow_rule structure translator

From: Jiri Pirko <[email-masked]>
Date: Thu, 22 Nov 2018 07:19:52 +0100

Thu, Nov 22, 2018 at 05:57:31AM CET, [email-masked] wrote:
>
>
>On 11/20/2018 6:51 PM, Pablo Neira Ayuso wrote:
>> This patch adds a function to translate the ethtool_rx_flow_spec
>> structure to the flow_rule representation.
>> 
>> This allows us to reuse code from the driver side given that both flower
>> and ethtool_rx_flow interfaces use the same representation.
>> 
>> Signed-off-by: Pablo Neira Ayuso <[email-masked]>
>> ---
>> v3: Suggested by Jiri Pirko:
>>         - Add struct ethtool_rx_flow_rule, keep placeholder to private
>>           dissector information.
>>     Reported by Manish Chopra:
>> 	- Fix incorrect dissector user_keys flags.
>> 
>>  include/linux/ethtool.h |  10 +++
>>  net/core/ethtool.c      | 189 ++++++++++++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 199 insertions(+)
>> 
>> diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
>> index afd9596ce636..99849e0858b2 100644
>> --- a/include/linux/ethtool.h
>> +++ b/include/linux/ethtool.h
>> @@ -400,4 +400,14 @@ struct ethtool_ops {
>>  	void	(*get_ethtool_phy_stats)(struct net_device *,
>>  					 struct ethtool_stats *, u64 *);
>>  };
>> +
>> +struct ethtool_rx_flow_rule {
>> +	struct flow_rule	*rule;
>> +	unsigned long		priv[0];
>> +};
>> +
>> +struct ethtool_rx_flow_rule *
>> +ethtool_rx_flow_rule_alloc(const struct ethtool_rx_flow_spec *fs);
>> +void ethtool_rx_flow_rule_free(struct ethtool_rx_flow_rule *rule);
>> +
>>  #endif /* _LINUX_ETHTOOL_H */
>> diff --git a/net/core/ethtool.c b/net/core/ethtool.c
>> index d05402868575..e679d6478371 100644
>> --- a/net/core/ethtool.c
>> +++ b/net/core/ethtool.c
>> @@ -28,6 +28,7 @@
>>  #include <linux/sched/signal.h>
>>  #include <linux/net.h>
>>  #include <net/xdp_sock.h>
>> +#include <net/flow_offload.h>
>>  
>>  /*
>>   * Some useful ethtool_ops methods that're device independent.
>> @@ -2808,3 +2809,191 @@ int dev_ethtool(struct net *net, struct ifreq *ifr)
>>  
>>  	return rc;
>>  }
>> +
>> +struct ethtool_rx_flow_key {
>> +	struct flow_dissector_key_basic			basic;
>> +	union {
>> +		struct flow_dissector_key_ipv4_addrs	ipv4;
>> +		struct flow_dissector_key_ipv6_addrs	ipv6;
>> +	};
>> +	struct flow_dissector_key_ports			tp;
>> +	struct flow_dissector_key_ip			ip;
>> +} __aligned(BITS_PER_LONG / 8); /* Ensure that we can do comparisons as longs. */
>> +
>> +struct ethtool_rx_flow_match {
>> +	struct flow_dissector		dissector;
>> +	struct ethtool_rx_flow_key	key;
>> +	struct ethtool_rx_flow_key	mask;
>> +};
>> +
>> +struct ethtool_rx_flow_rule *
>> +ethtool_rx_flow_rule_alloc(const struct ethtool_rx_flow_spec *fs)
>
>This is more than alloc, it's allocate and map, no reason to split the
>two operations AFAICT, but the name could be improved, how about
>alloc_from()?

Or ethtool_rx_flow_rule_create() and ethtool_rx_flow_rule_destroy()

>
>> +{
>> +	static struct in6_addr zero_addr = {};
>> +	struct ethtool_rx_flow_match *match;
>> +	struct ethtool_rx_flow_rule *flow;
>> +	struct flow_action_entry *act;
>> +
>> +	flow = kzalloc(sizeof(struct ethtool_rx_flow_rule) +
>> +		       sizeof(struct ethtool_rx_flow_match), GFP_KERNEL);
>> +	if (!flow)
>> +		return NULL;
>> +
>> +	/* ethtool_rx supports only one single action per rule. */
>> +	flow->rule = flow_rule_alloc(1);
>> +	if (!flow->rule) {
>> +		kfree(flow);
>> +		return NULL;
>> +	}
>> +
>> +	match = (struct ethtool_rx_flow_match *)flow->priv;
>> +	flow->rule->match.dissector	= &match->dissector;
>> +	flow->rule->match.mask		= &match->mask;
>> +	flow->rule->match.key		= &match->key;
>> +
>> +	match->mask.basic.n_proto = 0xffff;
>> +
>> +	switch (fs->flow_type & ~FLOW_EXT) {
>> +	case TCP_V4_FLOW:
>> +	case UDP_V4_FLOW: {
>> +		const struct ethtool_tcpip4_spec *v4_spec, *v4_m_spec;
>> +
>> +		match->key.basic.n_proto = htons(ETH_P_IP);
>> +
>> +		v4_spec = &fs->h_u.tcp_ip4_spec;
>> +		v4_m_spec = &fs->m_u.tcp_ip4_spec;
>> +
>> +		if (v4_m_spec->ip4src) {
>> +			match->key.ipv4.src = v4_spec->ip4src;
>> +			match->mask.ipv4.src = v4_m_spec->ip4src;
>> +		}
>> +		if (v4_m_spec->ip4dst) {
>> +			match->key.ipv4.dst = v4_spec->ip4dst;
>> +			match->mask.ipv4.dst = v4_m_spec->ip4dst;
>> +		}
>
>I got confused a while ago between the ethtool ntuple and nfc semantics,
>and I can't remember if the following is true:
>
>- bits set to 1 indicate a match and bit set to 0 indicate a don't care
>for nfc
>- bits set to 0 indicate a match and bit set to 1 indicate a don't care
>for ntuple
>
>Depending on the answer that could mean that this check on a zero
>address may have to change.
>
>> +		if (v4_m_spec->ip4src ||
>> +		    v4_m_spec->ip4dst) {
>> +			match->dissector.used_keys |=
>> +				(1 << FLOW_DISSECTOR_KEY_IPV4_ADDRS);
>
>Can you use BIT() here (and likewise for every one below).
>
>[snip]
>> +
>> +	return flow;
>
>What about the extended fields and non-IP protocols?
>-- 
>Florian