[patch iproute2-next 0/2] devlink: get devlink port for ifname using RTNL get link command

[patch iproute2-next 0/2] devlink: get devlink port for ifname using RTNL get link command

[Jiri Pirko]

From: Jiri Pirko <jiri@nvidia.com>

Patch #2 is benefiting of newly added IFLA_DEVLINK_PORT attribute
exposing netdev link to devlink port directly. Patch #1 is just
dependency for patch #2.

Jiri Pirko (2):
  devlink: add ifname_map_add/del() helpers
  devlink: get devlink port for ifname using RTNL get link command

 devlink/devlink.c | 118 ++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 109 insertions(+), 9 deletions(-)

-- 
2.37.3

[patch iproute2-next 1/2] devlink: add ifname_map_add/del() helpers

[Jiri Pirko]

From: Jiri Pirko <jiri@nvidia.com>

Add couple of helpers to alloc/free of map object alongside with list
addition/removal.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
---
 devlink/devlink.c | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/devlink/devlink.c b/devlink/devlink.c
index 8aefa101b2f8..308c0dbd1225 100644
--- a/devlink/devlink.c
+++ b/devlink/devlink.c
@@ -774,16 +774,35 @@ static int function_attr_cb(const struct nlattr *attr, void *data)
 	return MNL_CB_OK;
 }
 
+static int ifname_map_add(struct dl *dl, const char *ifname,
+			  const char *bus_name, const char *dev_name,
+			  uint32_t port_index)
+{
+	struct ifname_map *ifname_map;
+
+	ifname_map = ifname_map_alloc(bus_name, dev_name, port_index, ifname);
+	if (!ifname_map)
+		return -ENOMEM;
+	list_add(&ifname_map->list, &dl->ifname_map_list);
+	return 0;
+}
+
+static void ifname_map_del(struct ifname_map *ifname_map)
+{
+	list_del(&ifname_map->list);
+	ifname_map_free(ifname_map);
+}
+
 static int ifname_map_cb(const struct nlmsghdr *nlh, void *data)
 {
 	struct nlattr *tb[DEVLINK_ATTR_MAX + 1] = {};
 	struct genlmsghdr *genl = mnl_nlmsg_get_payload(nlh);
 	struct dl *dl = data;
-	struct ifname_map *ifname_map;
 	const char *bus_name;
 	const char *dev_name;
 	uint32_t port_index;
 	const char *port_ifname;
+	int err;
 
 	mnl_attr_parse(nlh, sizeof(*genl), attr_cb, tb);
 	if (!tb[DEVLINK_ATTR_BUS_NAME] || !tb[DEVLINK_ATTR_DEV_NAME] ||
@@ -797,11 +816,9 @@ static int ifname_map_cb(const struct nlmsghdr *nlh, void *data)
 	dev_name = mnl_attr_get_str(tb[DEVLINK_ATTR_DEV_NAME]);
 	port_index = mnl_attr_get_u32(tb[DEVLINK_ATTR_PORT_INDEX]);
 	port_ifname = mnl_attr_get_str(tb[DEVLINK_ATTR_PORT_NETDEV_NAME]);
-	ifname_map = ifname_map_alloc(bus_name, dev_name,
-				      port_index, port_ifname);
-	if (!ifname_map)
+	err = ifname_map_add(dl, port_ifname, bus_name, dev_name, port_index);
+	if (err)
 		return MNL_CB_ERROR;
-	list_add(&ifname_map->list, &dl->ifname_map_list);
 
 	return MNL_CB_OK;
 }
@@ -812,8 +829,7 @@ static void ifname_map_fini(struct dl *dl)
 
 	list_for_each_entry_safe(ifname_map, tmp,
 				 &dl->ifname_map_list, list) {
-		list_del(&ifname_map->list);
-		ifname_map_free(ifname_map);
+		ifname_map_del(ifname_map);
 	}
 }
 
-- 
2.37.3

[patch iproute2-next 2/2] devlink: get devlink port for ifname using RTNL get link command

[Jiri Pirko]

From: Jiri Pirko <jiri@nvidia.com>

Currently, when user specifies ifname as a handle on command line of
devlink, the related devlink port is looked-up in previously taken dump
of all devlink ports on the system. There are 3 problems with that:
1) The dump iterates over all devlink instances in kernel and takes a
   devlink instance lock for each.
2) Dumping all devlink ports would not scale.
3) Alternative ifnames are not exposed by devlink netlink interface.

Instead, benefit from RTNL get link command extension and get the
devlink port handle info from IFLA_DEVLINK_PORT attribute, if supported.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
---
 devlink/devlink.c | 88 +++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 86 insertions(+), 2 deletions(-)

diff --git a/devlink/devlink.c b/devlink/devlink.c
index 308c0dbd1225..dce7d85ea012 100644
--- a/devlink/devlink.c
+++ b/devlink/devlink.c
@@ -43,6 +43,8 @@
 #include "json_print.h"
 #include "utils.h"
 #include "namespace.h"
+#include "libnetlink.h"
+#include "../ip/ip_common.h"
 
 #define ESWITCH_MODE_LEGACY "legacy"
 #define ESWITCH_MODE_SWITCHDEV "switchdev"
@@ -793,6 +795,81 @@ static void ifname_map_del(struct ifname_map *ifname_map)
 	ifname_map_free(ifname_map);
 }
 
+static int ifname_map_rtnl_port_parse(struct dl *dl, const char *ifname,
+				      struct rtattr *nest)
+{
+	struct rtattr *tb[DEVLINK_ATTR_MAX + 1];
+	const char *bus_name;
+	const char *dev_name;
+	uint32_t port_index;
+
+	parse_rtattr_nested(tb, DEVLINK_ATTR_MAX, nest);
+	if (!tb[DEVLINK_ATTR_BUS_NAME] || !tb[DEVLINK_ATTR_DEV_NAME] ||
+	    !tb[DEVLINK_ATTR_PORT_INDEX])
+		return -ENOENT;
+
+	bus_name = rta_getattr_str(tb[DEVLINK_ATTR_BUS_NAME]);
+	dev_name = rta_getattr_str(tb[DEVLINK_ATTR_DEV_NAME]);
+	port_index = rta_getattr_u32(tb[DEVLINK_ATTR_PORT_INDEX]);
+	return ifname_map_add(dl, ifname, bus_name, dev_name, port_index);
+}
+
+static int ifname_map_rtnl_init(struct dl *dl, const char *ifname)
+{
+	struct iplink_req req = {
+		.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
+		.n.nlmsg_flags = NLM_F_REQUEST,
+		.n.nlmsg_type = RTM_GETLINK,
+		.i.ifi_family = AF_UNSPEC,
+	};
+	struct rtattr *tb[IFLA_MAX + 1];
+	struct rtnl_handle rth;
+	struct ifinfomsg *ifi;
+	struct nlmsghdr *n;
+	int len;
+	int err;
+
+	if (rtnl_open(&rth, 0) < 0) {
+		pr_err("Cannot open rtnetlink\n");
+		return -EINVAL;
+	}
+
+	addattr_l(&req.n, sizeof(req),
+		  !check_ifname(ifname) ? IFLA_IFNAME : IFLA_ALT_IFNAME,
+		  ifname, strlen(ifname) + 1);
+
+	if (rtnl_talk(&rth, &req.n, &n) < 0) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	if (n->nlmsg_type != RTM_NEWLINK) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	ifi = NLMSG_DATA(n);
+	len = n->nlmsg_len;
+
+	len -= NLMSG_LENGTH(sizeof(*ifi));
+	if (len < 0) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	parse_rtattr_flags(tb, IFLA_MAX, IFLA_RTA(ifi), len, NLA_F_NESTED);
+	if (!tb[IFLA_DEVLINK_PORT]) {
+		err = -EOPNOTSUPP;
+		goto out;
+	}
+
+	err = ifname_map_rtnl_port_parse(dl, ifname, tb[IFLA_DEVLINK_PORT]);
+
+out:
+	rtnl_close(&rth);
+	return err;
+}
+
 static int ifname_map_cb(const struct nlmsghdr *nlh, void *data)
 {
 	struct nlattr *tb[DEVLINK_ATTR_MAX + 1] = {};
@@ -838,11 +915,18 @@ static void ifname_map_init(struct dl *dl)
 	INIT_LIST_HEAD(&dl->ifname_map_list);
 }
 
-static int ifname_map_load(struct dl *dl)
+static int ifname_map_load(struct dl *dl, const char *ifname)
 {
 	struct nlmsghdr *nlh;
 	int err;
 
+	err = ifname_map_rtnl_init(dl, ifname);
+	if (!err)
+		return 0;
+	/* In case kernel does not support devlink port info passed over
+	 * RT netlink, fall-back to ports dump.
+	 */
+
 	nlh = mnlu_gen_socket_cmd_prepare(&dl->nlg, DEVLINK_CMD_PORT_GET,
 			       NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP);
 
@@ -862,7 +946,7 @@ static int ifname_map_lookup(struct dl *dl, const char *ifname,
 	int err;
 
 	if (!dl->map_loaded) {
-		err = ifname_map_load(dl);
+		err = ifname_map_load(dl, ifname);
 		if (err) {
 			pr_err("Failed to create index map\n");
 			return err;
-- 
2.37.3

Re: [patch iproute2-next 2/2] devlink: get devlink port for ifname using RTNL get link command

[Jiri Pirko]

Mon, Nov 07, 2022 at 05:53:48PM CET, jiri@resnulli.us wrote:
>@@ -838,11 +915,18 @@ static void ifname_map_init(struct dl *dl)
> 	INIT_LIST_HEAD(&dl->ifname_map_list);
> }
> 
>-static int ifname_map_load(struct dl *dl)
>+static int ifname_map_load(struct dl *dl, const char *ifname)
> {
> 	struct nlmsghdr *nlh;
> 	int err;
> 
>+	err = ifname_map_rtnl_init(dl, ifname);

Ah, I found a bug and the fix for it conflicts with this hunk. Please
drop this, I will send the bugfix first and then will send this again,
rebased.

Sorry for the mess!