On 05/23/2013 04:42 PM, Pablo Neira Ayuso wrote:
> This patch adds the capability to attach expectations to unconfirmed
> conntrack entries. This patch is required by the DHCPv6 helper in
> user-space.
>
> Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
> ---
> include/net/netfilter/nf_conntrack.h | 4 ++++
> include/uapi/linux/netfilter/nfnetlink_conntrack.h | 1 +
> net/netfilter/nf_conntrack_core.c | 20 ++++++++++++++++++++
> net/netfilter/nf_conntrack_netlink.c | 14 ++++++++++++--
> 4 files changed, 37 insertions(+), 2 deletions(-)
>
> diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
> index 644d9c2..d172fc5 100644
> --- a/include/net/netfilter/nf_conntrack.h
> +++ b/include/net/netfilter/nf_conntrack.h
> @@ -180,6 +180,10 @@ extern struct nf_conntrack_tuple_hash *
> __nf_conntrack_find(struct net *net, u16 zone,
> const struct nf_conntrack_tuple *tuple);
>
> +struct nf_conntrack_tuple_hash *
> +nf_ct_unconfirmed_find(struct net *net, u16 zone,
> + const struct nf_conntrack_tuple *tuple);
> +
> extern int nf_conntrack_hash_check_insert(struct nf_conn *ct);
> extern void nf_ct_delete_from_lists(struct nf_conn *ct);
> extern void nf_ct_dying_timeout(struct nf_conn *ct);
> diff --git a/include/uapi/linux/netfilter/nfnetlink_conntrack.h b/include/uapi/linux/netfilter/nfnetlink_conntrack.h
> index 08fabc6..8f7c2fe 100644
> --- a/include/uapi/linux/netfilter/nfnetlink_conntrack.h
> +++ b/include/uapi/linux/netfilter/nfnetlink_conntrack.h
> @@ -187,6 +187,7 @@ enum ctattr_expect {
> CTA_EXPECT_CLASS,
> CTA_EXPECT_NAT,
> CTA_EXPECT_FN,
> + CTA_EXPECT_MASTER_STATUS,
> __CTA_EXPECT_MAX
> };
> #define CTA_EXPECT_MAX (__CTA_EXPECT_MAX - 1)
> diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
> index ebb81d6..a6e5764 100644
> --- a/net/netfilter/nf_conntrack_core.c
> +++ b/net/netfilter/nf_conntrack_core.c
> @@ -401,6 +401,26 @@ nf_conntrack_find_get(struct net *net, u16 zone,
> }
> EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
>
> +struct nf_conntrack_tuple_hash *
> +nf_ct_unconfirmed_find(struct net *net, u16 zone,
> + const struct nf_conntrack_tuple *tuple)
> +{
> + struct nf_conntrack_tuple_hash *h, *ret = NULL;
> + struct hlist_nulls_node *n;
> +
> + rcu_read_lock();
> + hlist_nulls_for_each_entry_rcu(h, n, &net->ct.unconfirmed, hnnode) {
> + if (nf_ct_tuple_equal(tuple, &h->tuple) &&
> + nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)) == zone) {
> + ret = h;
Shouldn't we get reference of nf_ct_tuplehash_to_ctrack(h) here?
ctnetlink_create_expect will call nf_ct_put to release the reference finally.
or I miss something?
> + break;
> + }
> + }
> + rcu_read_unlock();
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(nf_ct_unconfirmed_find);
> +
> static void __nf_conntrack_hash_insert(struct nf_conn *ct,
> unsigned int hash,
> unsigned int repl_hash)
> diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
> index 6d0f8a1..3596682 100644
> --- a/net/netfilter/nf_conntrack_netlink.c
> +++ b/net/netfilter/nf_conntrack_netlink.c
> @@ -2742,7 +2742,7 @@ ctnetlink_create_expect(struct net *net, u16 zone,
> struct nf_conn *ct;
> struct nf_conn_help *help;
> struct nf_conntrack_helper *helper = NULL;
> - u_int32_t class = 0;
> + u_int32_t class = 0, master_status;
> int err = 0;
>
> /* caller guarantees that those three CTA_EXPECT_* exist */
> @@ -2756,8 +2756,18 @@ ctnetlink_create_expect(struct net *net, u16 zone,
> if (err < 0)
> return err;
>
> + if (cda[CTA_EXPECT_MASTER_STATUS]) {
> + master_status =
> + ntohl(nla_get_be32(cda[CTA_EXPECT_MASTER_STATUS]));
> + } else
> + master_status = IPS_CONFIRMED;
> +
> /* Look for master conntrack of this expectation */
> - h = nf_conntrack_find_get(net, zone, &master_tuple);
> + if (master_status & IPS_CONFIRMED)
> + h = nf_conntrack_find_get(net, zone, &master_tuple);
> + else
> + h = nf_ct_unconfirmed_find(net, zone, &master_tuple);
> +
> if (!h)
> return -ENOENT;
> ct = nf_ct_tuplehash_to_ctrack(h);
>
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