On 5 February 2016 at 17:41, Jarno Rajahalme <jarno@xxxxxxx> wrote:
> There is no need to help connections that are not confirmed, so we can
> delay helping new connections to the time when they are confirmed.
> This change is needed for NAT support, and having this as a separate
> patch will make the following NAT patch a bit easier to review.
>
> Signed-off-by: Jarno Rajahalme <jarno@xxxxxxx>
> ---
> net/openvswitch/conntrack.c | 20 +++++++++++++++-----
> 1 file changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
> index fa9ab25..fc0ef11 100644
> --- a/net/openvswitch/conntrack.c
> +++ b/net/openvswitch/conntrack.c
> @@ -464,6 +464,7 @@ static bool skb_nfct_cached(struct net *net,
> /* Pass 'skb' through conntrack in 'net', using zone configured in 'info', if
> * not done already. Update key with new CT state after passing the packet
> * through conntrack.
> + * Note that invalid packets are accepted while the skb->nfct remains unset!
> */
> static int __ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
> const struct ovs_conntrack_info *info,
This seems unrelated to the patch.
I *think* that you're trying to say that 'if the packet is deemed
invalid by conntrack, skb->nfct will be set to NULL and 0 will be
returned.' I think that this is a documentation issue separate from
this patch (Maybe could be combined with one of the earlier fragments
in the series?).
> @@ -474,7 +475,11 @@ static int __ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
> * actually run the packet through conntrack twice unless it's for a
> * different zone.
> */
> - if (!skb_nfct_cached(net, key, info, skb)) {
> + bool cached = skb_nfct_cached(net, key, info, skb);
> + enum ip_conntrack_info ctinfo;
> + struct nf_conn *ct;
> +
> + if (!cached) {
> struct nf_conn *tmpl = info->ct;
> int err;
>
> @@ -497,11 +502,16 @@ static int __ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
> return -ENOENT;
>
> ovs_ct_update_key(skb, info, key, true);
> + }
>
> - if (ovs_ct_helper(skb, info->family) != NF_ACCEPT) {
> - WARN_ONCE(1, "helper rejected packet");
> - return -EINVAL;
> - }
> + /* Call the helper right after nf_conntrack_in() for confirmed
> + * connections, but only when commiting for unconfirmed connections.
> + */
> + ct = nf_ct_get(skb, &ctinfo);
> + if (ct && (nf_ct_is_confirmed(ct) ? !cached : info->commit)
> + && ovs_ct_helper(skb, info->family) != NF_ACCEPT) {
> + WARN_ONCE(1, "helper rejected packet");
> + return -EINVAL;
> }
The comment points out what I think is the more obvious piece here:
that the helper should be executed when the connection is/will be
committed. The piece that I found less obvious was that "cached"
implies that the helper was already executed (and therefore it
shouldn't be run again). I don't know if there's a way to make this
more obvious, for example with a "helper_executed" variable or
similar. Up to you.
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