diff mbox series

[iproute2-next,v3,4/6] devlink: introduce support for netns id for nested handle

Message ID 20231024100403.762862-5-jiri@resnulli.us (mailing list archive)
State Superseded
Delegated to: David Ahern
Headers show
Series expose devlink instances relationships | expand

Checks

Context Check Description
netdev/tree_selection success Not a local patch

Commit Message

Jiri Pirko Oct. 24, 2023, 10:04 a.m. UTC 
From: Jiri Pirko <jiri@nvidia.com>

Nested handle may contain DEVLINK_ATTR_NETNS_ID attribute that indicates
the network namespace where the nested devlink instance resides. Process
this converting to netns name if possible and print to user.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
---
v2->v3:
- moved netns_name_by_id() into lib/namespace.c
- s/netns_name_by_id/netns_name_from_id/
- rebased on top of new patch "devlink: extend pr_out_nested_handle() to
  print object"
v1->v2:
- use previously introduced netns_netnsid_from_name() instead of code
  duplication for the same function.
- s/nesns_name_by_id_func/netns_name_by_id_func/
---
 devlink/devlink.c   | 23 ++++++++++++++++++++++-
 include/namespace.h |  1 +
 lib/namespace.c     | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 57 insertions(+), 1 deletion(-)

Comments

David Ahern Oct. 26, 2023, 5:08 p.m. UTC | #1 
On 10/24/23 4:04 AM, Jiri Pirko wrote:
> From: Jiri Pirko <jiri@nvidia.com>
> 
> Nested handle may contain DEVLINK_ATTR_NETNS_ID attribute that indicates
> the network namespace where the nested devlink instance resides. Process
> this converting to netns name if possible and print to user.
> 
> Signed-off-by: Jiri Pirko <jiri@nvidia.com>
> ---
> v2->v3:
> - moved netns_name_by_id() into lib/namespace.c
> - s/netns_name_by_id/netns_name_from_id/
> - rebased on top of new patch "devlink: extend pr_out_nested_handle() to
>   print object"
> v1->v2:
> - use previously introduced netns_netnsid_from_name() instead of code
>   duplication for the same function.
> - s/nesns_name_by_id_func/netns_name_by_id_func/
> ---
>  devlink/devlink.c   | 23 ++++++++++++++++++++++-
>  include/namespace.h |  1 +
>  lib/namespace.c     | 34 ++++++++++++++++++++++++++++++++++
>  3 files changed, 57 insertions(+), 1 deletion(-)
> 
> diff --git a/devlink/devlink.c b/devlink/devlink.c
> index f7325477f271..7ba2d0dcac72 100644
> --- a/devlink/devlink.c
> +++ b/devlink/devlink.c
> @@ -24,6 +24,7 @@
>  #include <linux/genetlink.h>
>  #include <linux/devlink.h>
>  #include <linux/netlink.h>
> +#include <linux/net_namespace.h>
>  #include <libmnl/libmnl.h>
>  #include <netinet/ether.h>
>  #include <sys/select.h>
> @@ -722,6 +723,7 @@ static const enum mnl_attr_data_type devlink_policy[DEVLINK_ATTR_MAX + 1] = {
>  	[DEVLINK_ATTR_LINECARD_SUPPORTED_TYPES] = MNL_TYPE_NESTED,
>  	[DEVLINK_ATTR_NESTED_DEVLINK] = MNL_TYPE_NESTED,
>  	[DEVLINK_ATTR_SELFTESTS] = MNL_TYPE_NESTED,
> +	[DEVLINK_ATTR_NETNS_ID] = MNL_TYPE_U32,
>  };
>  
>  static const enum mnl_attr_data_type
> @@ -2865,7 +2867,26 @@ static void __pr_out_nested_handle(struct dl *dl, struct nlattr *nla_nested_dl,
>  		return;
>  	}
>  
> -	__pr_out_handle_start(dl, tb, false, false);
> +	__pr_out_handle_start(dl, tb, tb[DEVLINK_ATTR_NETNS_ID], false);
> +	if (tb[DEVLINK_ATTR_NETNS_ID]) {
> +		int32_t id = mnl_attr_get_u32(tb[DEVLINK_ATTR_NETNS_ID]);
> +
> +		if (id >= 0) {

why does the kernel side even add DEVLINK_ATTR_NETNS_ID if
peernet2id_alloc fails?


> +			char *name = netns_name_from_id(id);
> +
> +			if (name) {
> +				print_string(PRINT_ANY, "netns",
> +					     " netns %s", name);
> +				free(name);
> +			} else {
> +				print_int(PRINT_ANY, "netnsid",
> +					  " netnsid %d", id);
> +			}
> +		} else {
> +			print_string(PRINT_FP, NULL, " netnsid %s", "unknown");
> +			print_int(PRINT_JSON, "netnsid", NULL, id);

ie., how is -1 useful to userspace?


> +		}
> +	}
>  	pr_out_handle_end(dl);
>  }
>
Jiri Pirko Oct. 27, 2023, 8:29 a.m. UTC | #2 
Thu, Oct 26, 2023 at 07:08:04PM CEST, dsahern@gmail.com wrote:
>On 10/24/23 4:04 AM, Jiri Pirko wrote:
>> From: Jiri Pirko <jiri@nvidia.com>
>> 
>> Nested handle may contain DEVLINK_ATTR_NETNS_ID attribute that indicates
>> the network namespace where the nested devlink instance resides. Process
>> this converting to netns name if possible and print to user.
>> 
>> Signed-off-by: Jiri Pirko <jiri@nvidia.com>
>> ---
>> v2->v3:
>> - moved netns_name_by_id() into lib/namespace.c
>> - s/netns_name_by_id/netns_name_from_id/
>> - rebased on top of new patch "devlink: extend pr_out_nested_handle() to
>>   print object"
>> v1->v2:
>> - use previously introduced netns_netnsid_from_name() instead of code
>>   duplication for the same function.
>> - s/nesns_name_by_id_func/netns_name_by_id_func/
>> ---
>>  devlink/devlink.c   | 23 ++++++++++++++++++++++-
>>  include/namespace.h |  1 +
>>  lib/namespace.c     | 34 ++++++++++++++++++++++++++++++++++
>>  3 files changed, 57 insertions(+), 1 deletion(-)
>> 
>> diff --git a/devlink/devlink.c b/devlink/devlink.c
>> index f7325477f271..7ba2d0dcac72 100644
>> --- a/devlink/devlink.c
>> +++ b/devlink/devlink.c
>> @@ -24,6 +24,7 @@
>>  #include <linux/genetlink.h>
>>  #include <linux/devlink.h>
>>  #include <linux/netlink.h>
>> +#include <linux/net_namespace.h>
>>  #include <libmnl/libmnl.h>
>>  #include <netinet/ether.h>
>>  #include <sys/select.h>
>> @@ -722,6 +723,7 @@ static const enum mnl_attr_data_type devlink_policy[DEVLINK_ATTR_MAX + 1] = {
>>  	[DEVLINK_ATTR_LINECARD_SUPPORTED_TYPES] = MNL_TYPE_NESTED,
>>  	[DEVLINK_ATTR_NESTED_DEVLINK] = MNL_TYPE_NESTED,
>>  	[DEVLINK_ATTR_SELFTESTS] = MNL_TYPE_NESTED,
>> +	[DEVLINK_ATTR_NETNS_ID] = MNL_TYPE_U32,
>>  };
>>  
>>  static const enum mnl_attr_data_type
>> @@ -2865,7 +2867,26 @@ static void __pr_out_nested_handle(struct dl *dl, struct nlattr *nla_nested_dl,
>>  		return;
>>  	}
>>  
>> -	__pr_out_handle_start(dl, tb, false, false);
>> +	__pr_out_handle_start(dl, tb, tb[DEVLINK_ATTR_NETNS_ID], false);
>> +	if (tb[DEVLINK_ATTR_NETNS_ID]) {
>> +		int32_t id = mnl_attr_get_u32(tb[DEVLINK_ATTR_NETNS_ID]);
>> +
>> +		if (id >= 0) {
>
>why does the kernel side even add DEVLINK_ATTR_NETNS_ID if
>peernet2id_alloc fails?

Yep. So the user knows that this is in a different namespace. This
logic is copied from iplink


>
>
>> +			char *name = netns_name_from_id(id);
>> +
>> +			if (name) {
>> +				print_string(PRINT_ANY, "netns",
>> +					     " netns %s", name);
>> +				free(name);
>> +			} else {
>> +				print_int(PRINT_ANY, "netnsid",
>> +					  " netnsid %d", id);
>> +			}
>> +		} else {
>> +			print_string(PRINT_FP, NULL, " netnsid %s", "unknown");
>> +			print_int(PRINT_JSON, "netnsid", NULL, id);
>
>ie., how is -1 useful to userspace?

The userspace knows that this device is in a different netnamespace, but
it is unknown as peernet2id_alloc failed. Should be really a rare
corner case when system is under memory pressure.


>
>
>> +		}
>> +	}
>>  	pr_out_handle_end(dl);
>>  }
>>  
>
>
diff mbox series

Patch

diff --git a/devlink/devlink.c b/devlink/devlink.c
index f7325477f271..7ba2d0dcac72 100644
--- a/devlink/devlink.c
+++ b/devlink/devlink.c
@@ -24,6 +24,7 @@ 
 #include <linux/genetlink.h>
 #include <linux/devlink.h>
 #include <linux/netlink.h>
+#include <linux/net_namespace.h>
 #include <libmnl/libmnl.h>
 #include <netinet/ether.h>
 #include <sys/select.h>
@@ -722,6 +723,7 @@  static const enum mnl_attr_data_type devlink_policy[DEVLINK_ATTR_MAX + 1] = {
 	[DEVLINK_ATTR_LINECARD_SUPPORTED_TYPES] = MNL_TYPE_NESTED,
 	[DEVLINK_ATTR_NESTED_DEVLINK] = MNL_TYPE_NESTED,
 	[DEVLINK_ATTR_SELFTESTS] = MNL_TYPE_NESTED,
+	[DEVLINK_ATTR_NETNS_ID] = MNL_TYPE_U32,
 };
 
 static const enum mnl_attr_data_type
@@ -2865,7 +2867,26 @@  static void __pr_out_nested_handle(struct dl *dl, struct nlattr *nla_nested_dl,
 		return;
 	}
 
-	__pr_out_handle_start(dl, tb, false, false);
+	__pr_out_handle_start(dl, tb, tb[DEVLINK_ATTR_NETNS_ID], false);
+	if (tb[DEVLINK_ATTR_NETNS_ID]) {
+		int32_t id = mnl_attr_get_u32(tb[DEVLINK_ATTR_NETNS_ID]);
+
+		if (id >= 0) {
+			char *name = netns_name_from_id(id);
+
+			if (name) {
+				print_string(PRINT_ANY, "netns",
+					     " netns %s", name);
+				free(name);
+			} else {
+				print_int(PRINT_ANY, "netnsid",
+					  " netnsid %d", id);
+			}
+		} else {
+			print_string(PRINT_FP, NULL, " netnsid %s", "unknown");
+			print_int(PRINT_JSON, "netnsid", NULL, id);
+		}
+	}
 	pr_out_handle_end(dl);
 }
 
diff --git a/include/namespace.h b/include/namespace.h
index e860a4b8ee5b..fbdfbc9a1c3b 100644
--- a/include/namespace.h
+++ b/include/namespace.h
@@ -61,5 +61,6 @@  struct netns_func {
 };
 
 int netns_id_from_name(struct rtnl_handle *rtnl, const char *name);
+char *netns_name_from_id(int32_t id);
 
 #endif /* __NAMESPACE_H__ */
diff --git a/lib/namespace.c b/lib/namespace.c
index f03f4bbabceb..d3aeb9658e73 100644
--- a/lib/namespace.c
+++ b/lib/namespace.c
@@ -188,3 +188,37 @@  out:
 	free(answer);
 	return ret;
 }
+
+struct netns_name_from_id_ctx {
+	int32_t id;
+	char *name;
+	struct rtnl_handle *rth;
+};
+
+static int netns_name_from_id_func(char *nsname, void *arg)
+{
+	struct netns_name_from_id_ctx *ctx = arg;
+	int32_t ret;
+
+	ret = netns_id_from_name(ctx->rth, nsname);
+	if (ret < 0 || ret != ctx->id)
+		return 0;
+	ctx->name = strdup(nsname);
+	return 1;
+}
+
+char *netns_name_from_id(int32_t id)
+{
+	struct rtnl_handle rth;
+	struct netns_name_from_id_ctx ctx = {
+		.id = id,
+		.rth = &rth,
+	};
+
+	if (rtnl_open(&rth, 0) < 0)
+		return NULL;
+	netns_foreach(netns_name_from_id_func, &ctx);
+	rtnl_close(&rth);
+
+	return ctx.name;
+}