On Tue, Feb 5, 2019 at 12:57 PM Stanislav Fomichev <s...@google.com> wrote: > > This new argument will be used in the next patches for the > eth_get_headlen use case. eth_get_headlen calls flow dissector > with only data (without skb) so there is currently no way to > pull attached BPF flow dissector program. With this new argument, > we can amend the callers to explicitly pass network namespace > so we can use attached BPF program. > > Note: WARN_ON_ONCE(!net) will now trigger for eth_get_headlen users. > > Signed-off-by: Stanislav Fomichev <s...@google.com>
> /** > * __skb_flow_dissect - extract the flow_keys struct and return it > + * @net: associated network namespace, if NULL pulled from skb > * @skb: sk_buff to extract the flow from, can be NULL if the rest are > specified > * @flow_dissector: list of keys to dissect > * @target_container: target structure to put dissected values into > @@ -739,7 +740,8 @@ bool __skb_flow_bpf_dissect(struct bpf_prog *prog, > * > * Caller must take care of zeroing target container memory. > */ > -bool __skb_flow_dissect(const struct sk_buff *skb, > +bool __skb_flow_dissect(struct net *net, > + const struct sk_buff *skb, > struct flow_dissector *flow_dissector, > void *target_container, > void *data, __be16 proto, int nhoff, int hlen, > @@ -799,12 +801,11 @@ bool __skb_flow_dissect(const struct sk_buff *skb, > > rcu_read_lock(); > > - if (skb->dev) > - attached = > rcu_dereference(dev_net(skb->dev)->flow_dissector_prog); > - else if (skb->sk) > - attached = > rcu_dereference(sock_net(skb->sk)->flow_dissector_prog); > - else > - WARN_ON_ONCE(1); > + if (!net && skb) > + net = skb_net(skb); > + if (net) > + attached = rcu_dereference(net->flow_dissector_prog); > + WARN_ON_ONCE(!net); Instead of this just call skb_net(skb) in all callers of __skb_flow_dissect that are called with an skb argument directly? It may have to be able to handle skb == NULL args.
