On Thu, May 25, 2017 at 7:22 PM, Tom Herbert <t...@herbertland.com> wrote:
> On Thu, May 25, 2017 at 6:24 AM, Or Gerlitz <ogerl...@mellanox.com> wrote:
>> Add support for dissection of ip tos and ttl and ipv6 traffic-class
>> and hoplimit. Both are dissected into the same struct.
>> Uses similar call to ip dissection function as with tcp, arp and others.
>> +/**
>> + * struct flow_dissector_key_ip:
>> + * @tos: tos
>> + * @ttl: ttl
>> + */
>> +struct flow_dissector_key_ip {
>> + __u8 tos;
>> + __u8 ttl;
>> +};
>> --- a/net/core/flow_dissector.c
>> +++ b/net/core/flow_dissector.c
>> +static void
>> +__skb_flow_dissect_ipv4(const struct sk_buff *skb,
>> + struct flow_dissector *flow_dissector,
>> + void *target_container, void *data, const struct
>> iphdr *iph)
>> +{
>> + struct flow_dissector_key_ip *key_ip;
>> +
>> + if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IP))
>> + return;
>> +
>> + key_ip = skb_flow_dissector_target(flow_dissector,
>> + FLOW_DISSECTOR_KEY_IP,
>> + target_container);
>> + key_ip->tos = iph->tos;
>> + key_ip->ttl = iph->ttl;
>
> In an encapsulation this returns the tos and ttl of the encapsulated
> packet. Is that really useful to the caller? Seems more likely that
> they need the outer tos and ttl for forwarding.
In what we are dealing with, classification is carried after the
packet is decapsulated by the shared tunnel device. So even today,e.g
for the src/dst IP, the dissection is carried on what were the inner
fields before decap.
When we did the the flower patches for being able to classify on both
the inner and outer fields (say outer src/dst ip, tunnel key) for what
related to the macs/ips/ports/etc -- I don't think we touched the
existing dissection, I will look on that to see if I am wrong..
