diff mbox series

[net-next,v2,3/5] seg6: add callbacks for customizing the creation/destruction of a behavior

Message ID 20201107153139.3552-4-andrea.mayer@uniroma2.it (mailing list archive)
State Not Applicable
Delegated to: Netdev Maintainers
Headers show
Series [net-next,v2,1/5] vrf: add mac header for tunneled packets when sniffer is attached | expand

Commit Message

Andrea Mayer Nov. 7, 2020, 3:31 p.m. UTC
We introduce two callbacks used for customizing the creation/destruction of
a SRv6 behavior. Such callbacks are defined in the new struct
seg6_local_lwtunnel_ops and hereafter we provide a brief description of
them:

 - build_state(...): used for calling the custom constructor of the
   behavior during its initialization phase and after all the attributes
   have been parsed successfully;

 - destroy_state(...): used for calling the custom destructor of the
   behavior before it is completely destroyed.

Signed-off-by: Andrea Mayer <andrea.mayer@uniroma2.it>
---
 net/ipv6/seg6_local.c | 64 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

Comments

Jakub Kicinski Nov. 10, 2020, 10:56 p.m. UTC | #1
On Sat,  7 Nov 2020 16:31:37 +0100 Andrea Mayer wrote:
> We introduce two callbacks used for customizing the creation/destruction of
> a SRv6 behavior. Such callbacks are defined in the new struct
> seg6_local_lwtunnel_ops and hereafter we provide a brief description of
> them:
> 
>  - build_state(...): used for calling the custom constructor of the
>    behavior during its initialization phase and after all the attributes
>    have been parsed successfully;
> 
>  - destroy_state(...): used for calling the custom destructor of the
>    behavior before it is completely destroyed.
> 
> Signed-off-by: Andrea Mayer <andrea.mayer@uniroma2.it>

Looks good, minor nits.

> diff --git a/net/ipv6/seg6_local.c b/net/ipv6/seg6_local.c
> index 63a82e2fdea9..4b0f155d641d 100644
> --- a/net/ipv6/seg6_local.c
> +++ b/net/ipv6/seg6_local.c
> @@ -33,11 +33,23 @@
>  
>  struct seg6_local_lwt;
>  
> +typedef int (*slwt_build_state_t)(struct seg6_local_lwt *slwt, const void *cfg,
> +				  struct netlink_ext_ack *extack);
> +typedef void (*slwt_destroy_state_t)(struct seg6_local_lwt *slwt);

Let's avoid the typedefs. Instead of taking a pointer to the op take a
pointer to the ops struct in seg6_local_lwtunnel_build_state() etc.

> +/* callbacks used for customizing the creation and destruction of a behavior */
> +struct seg6_local_lwtunnel_ops {
> +	slwt_build_state_t build_state;
> +	slwt_destroy_state_t destroy_state;
> +};
> +
>  struct seg6_action_desc {
>  	int action;
>  	unsigned long attrs;
>  	int (*input)(struct sk_buff *skb, struct seg6_local_lwt *slwt);
>  	int static_headroom;
> +
> +	struct seg6_local_lwtunnel_ops slwt_ops;
>  };
>  
>  struct bpf_lwt_prog {
> @@ -1015,6 +1027,45 @@ static void destroy_attrs(struct seg6_local_lwt *slwt)
>  	__destroy_attrs(attrs, 0, SEG6_LOCAL_MAX + 1, slwt);
>  }
>  
> +/* call the custom constructor of the behavior during its initialization phase
> + * and after that all its attributes have been parsed successfully.
> + */
> +static int
> +seg6_local_lwtunnel_build_state(struct seg6_local_lwt *slwt, const void *cfg,
> +				struct netlink_ext_ack *extack)
> +{
> +	slwt_build_state_t build_func;
> +	struct seg6_action_desc *desc;
> +	int err = 0;
> +
> +	desc = slwt->desc;
> +	if (!desc)
> +		return -EINVAL;

This is impossible, right?

> +
> +	build_func = desc->slwt_ops.build_state;
> +	if (build_func)
> +		err = build_func(slwt, cfg, extack);
> +
> +	return err;

no need for err, just use return directly.

	if (!ops->build_state)
		return 0;
	return ops->build_state(...);

> +}
> +
> +/* call the custom destructor of the behavior which is invoked before the
> + * tunnel is going to be destroyed.
> + */
> +static void seg6_local_lwtunnel_destroy_state(struct seg6_local_lwt *slwt)
> +{
> +	slwt_destroy_state_t destroy_func;
> +	struct seg6_action_desc *desc;
> +
> +	desc = slwt->desc;
> +	if (!desc)
> +		return;
> +
> +	destroy_func = desc->slwt_ops.destroy_state;
> +	if (destroy_func)
> +		destroy_func(slwt);
> +}
> +
>  static int parse_nla_action(struct nlattr **attrs, struct seg6_local_lwt *slwt)
>  {
>  	struct seg6_action_param *param;
> @@ -1090,8 +1141,16 @@ static int seg6_local_build_state(struct net *net, struct nlattr *nla,
>  
>  	err = parse_nla_action(tb, slwt);
>  	if (err < 0)
> +		/* In case of error, the parse_nla_action() takes care of
> +		 * releasing resources which have been acquired during the
> +		 * processing of attributes.
> +		 */

that's the normal behavior for a kernel function, comment is
unnecessary IMO

>  		goto out_free;
>  
> +	err = seg6_local_lwtunnel_build_state(slwt, cfg, extack);
> +	if (err < 0)
> +		goto free_attrs;

The function is called destroy_attrs, call the label out_destroy_attrs,
or err_destroy_attrs.

>  	newts->type = LWTUNNEL_ENCAP_SEG6_LOCAL;
>  	newts->flags = LWTUNNEL_STATE_INPUT_REDIRECT;
>  	newts->headroom = slwt->headroom;
> @@ -1100,6 +1159,9 @@ static int seg6_local_build_state(struct net *net, struct nlattr *nla,
>  
>  	return 0;
>  
> +free_attrs:
> +	destroy_attrs(slwt);
> +

no need for empty lines on error paths

>  out_free:
>  	kfree(newts);
>  	return err;
> @@ -1109,6 +1171,8 @@ static void seg6_local_destroy_state(struct lwtunnel_state *lwt)
>  {
>  	struct seg6_local_lwt *slwt = seg6_local_lwtunnel(lwt);
>  
> +	seg6_local_lwtunnel_destroy_state(slwt);
> +
>  	destroy_attrs(slwt);
>  
>  	return;
Andrea Mayer Nov. 13, 2020, 1:06 a.m. UTC | #2
Hi Jakub,
many thanks for your review. Please see my responses inline:

On Tue, 10 Nov 2020 14:56:55 -0800
Jakub Kicinski <kuba@kernel.org> wrote:

> On Sat,  7 Nov 2020 16:31:37 +0100 Andrea Mayer wrote:
> > We introduce two callbacks used for customizing the creation/destruction of
> > a SRv6 behavior. Such callbacks are defined in the new struct
> > seg6_local_lwtunnel_ops and hereafter we provide a brief description of
> > them:
> > 
> >  - build_state(...): used for calling the custom constructor of the
> >    behavior during its initialization phase and after all the attributes
> >    have been parsed successfully;
> > 
> >  - destroy_state(...): used for calling the custom destructor of the
> >    behavior before it is completely destroyed.
> > 
> > Signed-off-by: Andrea Mayer <andrea.mayer@uniroma2.it>
> 
> Looks good, minor nits.
> 
> > diff --git a/net/ipv6/seg6_local.c b/net/ipv6/seg6_local.c
> > index 63a82e2fdea9..4b0f155d641d 100644
> > --- a/net/ipv6/seg6_local.c
> > +++ b/net/ipv6/seg6_local.c
> > @@ -33,11 +33,23 @@
> >  
> >  struct seg6_local_lwt;
> >  
> > +typedef int (*slwt_build_state_t)(struct seg6_local_lwt *slwt, const void *cfg,
> > +				  struct netlink_ext_ack *extack);
> > +typedef void (*slwt_destroy_state_t)(struct seg6_local_lwt *slwt);
> 
> Let's avoid the typedefs. Instead of taking a pointer to the op take a
> pointer to the ops struct in seg6_local_lwtunnel_build_state() etc.
>

Ok, I will do it this way in v3.

> > +/* callbacks used for customizing the creation and destruction of a behavior */
> > +struct seg6_local_lwtunnel_ops {
> > +	slwt_build_state_t build_state;
> > +	slwt_destroy_state_t destroy_state;
> > +};
> > +
> >  struct seg6_action_desc {
> >  	int action;
> >  	unsigned long attrs;
> >  	int (*input)(struct sk_buff *skb, struct seg6_local_lwt *slwt);
> >  	int static_headroom;
> > +
> > +	struct seg6_local_lwtunnel_ops slwt_ops;
> >  };
> >  
> >  struct bpf_lwt_prog {
> > @@ -1015,6 +1027,45 @@ static void destroy_attrs(struct seg6_local_lwt *slwt)
> >  	__destroy_attrs(attrs, 0, SEG6_LOCAL_MAX + 1, slwt);
> >  }
> >  
> > +/* call the custom constructor of the behavior during its initialization phase
> > + * and after that all its attributes have been parsed successfully.
> > + */
> > +static int
> > +seg6_local_lwtunnel_build_state(struct seg6_local_lwt *slwt, const void *cfg,
> > +				struct netlink_ext_ack *extack)
> > +{
> > +	slwt_build_state_t build_func;
> > +	struct seg6_action_desc *desc;
> > +	int err = 0;
> > +
> > +	desc = slwt->desc;
> > +	if (!desc)
> > +		return -EINVAL;
> 
> This is impossible, right?
> 

Yes, it is. I will remove this check in v3.

> > +
> > +	build_func = desc->slwt_ops.build_state;
> > +	if (build_func)
> > +		err = build_func(slwt, cfg, extack);
> > +
> > +	return err;
> 
> no need for err, just use return directly.
> 
> 	if (!ops->build_state)
> 		return 0;
> 	return ops->build_state(...);
> 

Ok, I will do it in this way in v3.

> > +}
> > +
> > +/* call the custom destructor of the behavior which is invoked before the
> > + * tunnel is going to be destroyed.
> > + */
> > +static void seg6_local_lwtunnel_destroy_state(struct seg6_local_lwt *slwt)
> > +{
> > +	slwt_destroy_state_t destroy_func;
> > +	struct seg6_action_desc *desc;
> > +
> > +	desc = slwt->desc;
> > +	if (!desc)
> > +		return;
> > +
> > +	destroy_func = desc->slwt_ops.destroy_state;
> > +	if (destroy_func)
> > +		destroy_func(slwt);
> > +}
> > +
> >  static int parse_nla_action(struct nlattr **attrs, struct seg6_local_lwt *slwt)
> >  {
> >  	struct seg6_action_param *param;
> > @@ -1090,8 +1141,16 @@ static int seg6_local_build_state(struct net *net, struct nlattr *nla,
> >  
> >  	err = parse_nla_action(tb, slwt);
> >  	if (err < 0)
> > +		/* In case of error, the parse_nla_action() takes care of
> > +		 * releasing resources which have been acquired during the
> > +		 * processing of attributes.
> > +		 */
> 
> that's the normal behavior for a kernel function, comment is
> unnecessary IMO
> 

Yes and this is the way it should be. But before this patch, the
parse_nla_action() in case of error did not always release all the acquired
resources. From this patcheset onward, the parse_nla_action() behaves like we
expect. Therefore, I will remove the comment in v3.

> >  		goto out_free;
> >  
> > +	err = seg6_local_lwtunnel_build_state(slwt, cfg, extack);
> > +	if (err < 0)
> > +		goto free_attrs;
> 
> The function is called destroy_attrs, call the label out_destroy_attrs,
> or err_destroy_attrs.
> 

Fine, I will stick with the out_destroy_attrs to be consistent and uniform with
the out_free label in v3.

> >  	newts->type = LWTUNNEL_ENCAP_SEG6_LOCAL;
> >  	newts->flags = LWTUNNEL_STATE_INPUT_REDIRECT;
> >  	newts->headroom = slwt->headroom;
> > @@ -1100,6 +1159,9 @@ static int seg6_local_build_state(struct net *net, struct nlattr *nla,
> >  
> >  	return 0;
> >  
> > +free_attrs:
> > +	destroy_attrs(slwt);
> > +
> 
> no need for empty lines on error paths
> 

Ok.

> >  out_free:
> >  	kfree(newts);
> >  	return err;
> > @@ -1109,6 +1171,8 @@ static void seg6_local_destroy_state(struct lwtunnel_state *lwt)
> >  {
> >  	struct seg6_local_lwt *slwt = seg6_local_lwtunnel(lwt);
> >  
> > +	seg6_local_lwtunnel_destroy_state(slwt);
> > +
> >  	destroy_attrs(slwt);
> >  
> >  	return;
> 

Thank you,
Andrea
diff mbox series

Patch

diff --git a/net/ipv6/seg6_local.c b/net/ipv6/seg6_local.c
index 63a82e2fdea9..4b0f155d641d 100644
--- a/net/ipv6/seg6_local.c
+++ b/net/ipv6/seg6_local.c
@@ -33,11 +33,23 @@ 
 
 struct seg6_local_lwt;
 
+typedef int (*slwt_build_state_t)(struct seg6_local_lwt *slwt, const void *cfg,
+				  struct netlink_ext_ack *extack);
+typedef void (*slwt_destroy_state_t)(struct seg6_local_lwt *slwt);
+
+/* callbacks used for customizing the creation and destruction of a behavior */
+struct seg6_local_lwtunnel_ops {
+	slwt_build_state_t build_state;
+	slwt_destroy_state_t destroy_state;
+};
+
 struct seg6_action_desc {
 	int action;
 	unsigned long attrs;
 	int (*input)(struct sk_buff *skb, struct seg6_local_lwt *slwt);
 	int static_headroom;
+
+	struct seg6_local_lwtunnel_ops slwt_ops;
 };
 
 struct bpf_lwt_prog {
@@ -1015,6 +1027,45 @@  static void destroy_attrs(struct seg6_local_lwt *slwt)
 	__destroy_attrs(attrs, 0, SEG6_LOCAL_MAX + 1, slwt);
 }
 
+/* call the custom constructor of the behavior during its initialization phase
+ * and after that all its attributes have been parsed successfully.
+ */
+static int
+seg6_local_lwtunnel_build_state(struct seg6_local_lwt *slwt, const void *cfg,
+				struct netlink_ext_ack *extack)
+{
+	slwt_build_state_t build_func;
+	struct seg6_action_desc *desc;
+	int err = 0;
+
+	desc = slwt->desc;
+	if (!desc)
+		return -EINVAL;
+
+	build_func = desc->slwt_ops.build_state;
+	if (build_func)
+		err = build_func(slwt, cfg, extack);
+
+	return err;
+}
+
+/* call the custom destructor of the behavior which is invoked before the
+ * tunnel is going to be destroyed.
+ */
+static void seg6_local_lwtunnel_destroy_state(struct seg6_local_lwt *slwt)
+{
+	slwt_destroy_state_t destroy_func;
+	struct seg6_action_desc *desc;
+
+	desc = slwt->desc;
+	if (!desc)
+		return;
+
+	destroy_func = desc->slwt_ops.destroy_state;
+	if (destroy_func)
+		destroy_func(slwt);
+}
+
 static int parse_nla_action(struct nlattr **attrs, struct seg6_local_lwt *slwt)
 {
 	struct seg6_action_param *param;
@@ -1090,8 +1141,16 @@  static int seg6_local_build_state(struct net *net, struct nlattr *nla,
 
 	err = parse_nla_action(tb, slwt);
 	if (err < 0)
+		/* In case of error, the parse_nla_action() takes care of
+		 * releasing resources which have been acquired during the
+		 * processing of attributes.
+		 */
 		goto out_free;
 
+	err = seg6_local_lwtunnel_build_state(slwt, cfg, extack);
+	if (err < 0)
+		goto free_attrs;
+
 	newts->type = LWTUNNEL_ENCAP_SEG6_LOCAL;
 	newts->flags = LWTUNNEL_STATE_INPUT_REDIRECT;
 	newts->headroom = slwt->headroom;
@@ -1100,6 +1159,9 @@  static int seg6_local_build_state(struct net *net, struct nlattr *nla,
 
 	return 0;
 
+free_attrs:
+	destroy_attrs(slwt);
+
 out_free:
 	kfree(newts);
 	return err;
@@ -1109,6 +1171,8 @@  static void seg6_local_destroy_state(struct lwtunnel_state *lwt)
 {
 	struct seg6_local_lwt *slwt = seg6_local_lwtunnel(lwt);
 
+	seg6_local_lwtunnel_destroy_state(slwt);
+
 	destroy_attrs(slwt);
 
 	return;