On Tue, Dec 29, 2015 at 12:29:09PM -0500, Craig Gallek wrote:
> From: Craig Gallek <[email protected]>
>
> Expose socket options for setting a classic or extended BPF program
> for use when selecting sockets in an SO_REUSEPORT group. These options
> can be used on the first socket to belong to a group before bind or
> on any socket in the group after bind.
>
> This change includes refactoring of the existing sk_filter code to
> allow reuse of the existing BPF filter validation checks.
>
> Signed-off-by: Craig Gallek <[email protected]>
...
> @@ -75,6 +79,10 @@ static struct sock_reuseport *reuseport_grow(struct
> sock_reuseport *reuse)
> rcu_assign_pointer(reuse->socks[i]->sk_reuseport_cb,
> more_reuse);
>
> + /* Note: we use kfree_rcu here instead of reuseport_free_rcu so
> + * that reuse and more_reuse can temporarily share a reference
> + * to prog.
> + */
> kfree_rcu(reuse, rcu);
> return more_reuse;
thanks for the comment. that bit definitely is tricky, but looks fine.
> +static struct sock *run_bpf(struct sock_reuseport *reuse, u16 socks,
> + struct bpf_prog *prog, struct sk_buff *skb,
> + int hdr_len)
> +{
> + struct sk_buff *nskb = NULL;
> + u32 index;
> +
> + if (skb_shared(skb)) {
> + nskb = skb_clone(skb, GFP_ATOMIC);
> + if (!nskb)
> + return NULL;
> + skb = nskb;
> + }
> +
> + /* temporarily advance data past protocol header */
> + if (!pskb_may_pull(skb, hdr_len) || !skb_pull_inline(skb, hdr_len)) {
pskb_pull() would be cleaner.
> + consume_skb(nskb);
> + return NULL;
> + }
> + index = bpf_prog_run_save_cb(prog, skb);
> + __skb_push(skb, hdr_len);
This indeed matches what normal bpf filters see with udp sockets, so
I guess that's fine.
Acked-by: Alexei Starovoitov <[email protected]>
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