Re: [PATCH] netfilter: remove duplicate code

From: Kangmin Park
Date: Mon Aug 09 2021 - 14:35:29 EST


I checked the Changes Requested state in patchwork.
But I have not received any review mails.
I wonder if there is any problem.
I'm sorry if you just review a little late due to a busy schedule.

Kangmin Park

2021년 8월 7일 (토) 오후 3:21, Kangmin Park <l4stpr0gr4m@xxxxxxxxx>님이 작성:
>
> nf_nat_ipv4_fn() and nf_nat_ipv6_fn() call nf_nat_inet_fn().
> Those two functions are already contains routine that gets nf_conn
> object and checks the untrackable situation.
> So, the following code is duplicated.
>
> ```
> ct = nf_ct_get(skb, &ctinfo);
> if (!ct)
> return NF_ACCEPT;
> ```
>
> Therefore, define a function __nf_nat_inet_fn() that has the same
> contents as the nf_nat_inet_fn() except for routine gets and checks
> the nf_conn object.
> Then, separate the nf_nat_inet_fn() into a routine that gets a
> nf_conn object and a routine that calls the __nf_nat_inet_fn().
>
> Signed-off-by: Kangmin Park <l4stpr0gr4m@xxxxxxxxx>
> ---
> include/net/netfilter/nf_nat.h | 5 +++++
> net/netfilter/nf_nat_core.c | 37 ++++++++++++++++++++++------------
> net/netfilter/nf_nat_proto.c | 4 ++--
> 3 files changed, 31 insertions(+), 15 deletions(-)
>
> diff --git a/include/net/netfilter/nf_nat.h b/include/net/netfilter/nf_nat.h
> index 987111ae5240..a66f617c5054 100644
> --- a/include/net/netfilter/nf_nat.h
> +++ b/include/net/netfilter/nf_nat.h
> @@ -100,6 +100,11 @@ void nf_nat_ipv6_unregister_fn(struct net *net, const struct nf_hook_ops *ops);
> int nf_nat_inet_register_fn(struct net *net, const struct nf_hook_ops *ops);
> void nf_nat_inet_unregister_fn(struct net *net, const struct nf_hook_ops *ops);
>
> +unsigned int
> +__nf_nat_inet_fn(void *priv, struct sk_buff *skb,
> + const struct nf_hook_state *state, struct nf_conn *ct,
> + enum ip_conntrack_info ctinfo);
> +
> unsigned int
> nf_nat_inet_fn(void *priv, struct sk_buff *skb,
> const struct nf_hook_state *state);
> diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
> index 7de595ead06a..98ebba2c0f6d 100644
> --- a/net/netfilter/nf_nat_core.c
> +++ b/net/netfilter/nf_nat_core.c
> @@ -682,25 +682,15 @@ unsigned int nf_nat_packet(struct nf_conn *ct,
> }
> EXPORT_SYMBOL_GPL(nf_nat_packet);
>
> unsigned int
> -nf_nat_inet_fn(void *priv, struct sk_buff *skb,
> - const struct nf_hook_state *state)
> +__nf_nat_inet_fn(void *priv, struct sk_buff *skb,
> + const struct nf_hook_state *state, struct nf_conn *ct,
> + enum ip_conntrack_info ctinfo)
> {
> - struct nf_conn *ct;
> - enum ip_conntrack_info ctinfo;
> struct nf_conn_nat *nat;
> /* maniptype == SRC for postrouting. */
> enum nf_nat_manip_type maniptype = HOOK2MANIP(state->hook);
>
> - ct = nf_ct_get(skb, &ctinfo);
> - /* Can't track? It's not due to stress, or conntrack would
> - * have dropped it. Hence it's the user's responsibilty to
> - * packet filter it out, or implement conntrack/NAT for that
> - * protocol. 8) --RR
> - */
> - if (!ct)
> - return NF_ACCEPT;
> -
> nat = nfct_nat(ct);
>
> switch (ctinfo) {
> @@ -755,6 +745,26 @@ nf_nat_inet_fn(void *priv, struct sk_buff *skb,
> nf_ct_kill_acct(ct, ctinfo, skb);
> return NF_DROP;
> }
> +EXPORT_SYMBOL_GPL(__nf_nat_inet_fn);
> +
> +unsigned int
> +nf_nat_inet_fn(void *priv, struct sk_buff *skb,
> + const struct nf_hook_state *state)
> +{
> + struct nf_conn *ct;
> + enum ip_conntrack_info ctinfo;
> +
> + ct = nf_ct_get(skb, &ctinfo);
> + /* Can't track? It's not due to stress, or conntrack would
> + * have dropped it. Hence it's the user's responsibilty to
> + * packet filter it out, or implement conntrack/NAT for that
> + * protocol. 8) --RR
> + */
> + if (!ct)
> + return NF_ACCEPT;
> +
> + return __nf_nat_inet_fn(priv, skb, state, ct, ctinfo);
> +}
> EXPORT_SYMBOL_GPL(nf_nat_inet_fn);
>
> struct nf_nat_proto_clean {
> diff --git a/net/netfilter/nf_nat_proto.c b/net/netfilter/nf_nat_proto.c
> index 48cc60084d28..897859730078 100644
> --- a/net/netfilter/nf_nat_proto.c
> +++ b/net/netfilter/nf_nat_proto.c
> @@ -642,7 +642,7 @@ nf_nat_ipv4_fn(void *priv, struct sk_buff *skb,
> }
> }
>
> - return nf_nat_inet_fn(priv, skb, state);
> + return __nf_nat_inet_fn(priv, skb, state, ct, ctinfo);
> }
>
> static unsigned int
> @@ -934,7 +934,7 @@ nf_nat_ipv6_fn(void *priv, struct sk_buff *skb,
> }
> }
>
> - return nf_nat_inet_fn(priv, skb, state);
> + return __nf_nat_inet_fn(priv, skb, state, ct, ctinfo);
> }
>
> static unsigned int
> --
> 2.26.2
>