[PATCH iproute2-next 0/2] ip: wwan links management support

This short series introduces support for WWAN links  support.

First patch adds support for new common attributes: parent device name
and parent device bus name. The former attribute required to create a
new WWAN link. Finally, the second patch introduces support for a new
'wwan' link type.

Changelong:
  RFC -> v1
    * drop the kernel headers update patch
    * add a parent device bus attribute support
    * shorten the 'parentdev-name' parameter to just 'parentdev'

Sergey Ryazanov (2):
  iplink: add support for parent device
  iplink: support for WWAN devices

 ip/Makefile      |  2 +-
 ip/ipaddress.c   | 14 ++++++++++
 ip/iplink.c      |  9 ++++--
 ip/iplink_wwan.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 94 insertions(+), 3 deletions(-)
 create mode 100644 ip/iplink_wwan.c

-- 
2.26.3

Add support for specifying a parent device (struct device) by its name
during the link creation and printing parent name in the links list.
This option will be used to create WWAN links and possibly by other
device classes that do not have a "natural parent netdev".

Add the parent device bus name printing for links list info
completeness. But do not add a corresponding command line argument, as
we do not have a use case for this attribute.

Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
---
 ip/ipaddress.c | 14 ++++++++++++++
 ip/iplink.c    |  6 +++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/ip/ipaddress.c b/ip/ipaddress.c
index 06ca7273..7dc38ff1 100644
--- a/ip/ipaddress.c
+++ b/ip/ipaddress.c

@@ -1242,6 +1242,20 @@ int print_linkinfo(struct nlmsghdr *n, void *arg)
 						   RTA_PAYLOAD(tb[IFLA_PHYS_SWITCH_ID]),
 						   b1, sizeof(b1)));
 		}
+
+		if (tb[IFLA_PARENT_DEV_BUS_NAME]) {
+			print_string(PRINT_ANY,
+				     "parentdevbus",
+				     "parentdevbus %s ",
+				     rta_getattr_str(tb[IFLA_PARENT_DEV_BUS_NAME]));
+		}
+
+		if (tb[IFLA_PARENT_DEV_NAME]) {
+			print_string(PRINT_ANY,
+				     "parentdev",
+				     "parentdev %s ",
+				     rta_getattr_str(tb[IFLA_PARENT_DEV_NAME]));
+		}
 	}
 
 	if ((do_link || show_details) && tb[IFLA_IFALIAS]) {

diff --git a/ip/iplink.c b/ip/iplink.c
index faafd7e8..33b7be30 100644
--- a/ip/iplink.c
+++ b/ip/iplink.c

@@ -63,7 +63,7 @@ void iplink_usage(void)
 {
 	if (iplink_have_newlink()) {
 		fprintf(stderr,
-			"Usage: ip link add [link DEV] [ name ] NAME\n"
+			"Usage: ip link add [link DEV | parentdev NAME] [ name ] NAME\n"
 			"		    [ txqueuelen PACKETS ]\n"
 			"		    [ address LLADDR ]\n"
 			"		    [ broadcast LLADDR ]\n"

@@ -938,6 +938,10 @@ int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
 				       *argv);
 			addattr32(&req->n, sizeof(*req),
 				  IFLA_GSO_MAX_SEGS, max_segs);
+		} else if (strcmp(*argv, "parentdev") == 0) {
+			NEXT_ARG();
+			addattr_l(&req->n, sizeof(*req), IFLA_PARENT_DEV_NAME,
+				  *argv, strlen(*argv) + 1);
 		} else {
 			if (matches(*argv, "help") == 0)
 				usage();

-- 
2.26.3

The WWAN subsystem has been extended to generalize the per data channel
network interfaces management. This change implements support for WWAN
links handling. And actively uses the earlier introduced ip-link
capability to specify the parent by its device name.

The WWAN interface for a new data channel should be created with a
command like this:

ip link add dev wwan0-2 parentdev wwan0 type wwan linkid 2

Where: wwan0 is the modem HW device name (should be taken from
/sys/class/wwan) and linkid is an identifier of the opened data
channel.

Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
---
 ip/Makefile      |  2 +-
 ip/iplink.c      |  3 +-
 ip/iplink_wwan.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 75 insertions(+), 2 deletions(-)
 create mode 100644 ip/iplink_wwan.c

diff --git a/ip/Makefile b/ip/Makefile
index 4cad619c..b03af29b 100644
--- a/ip/Makefile
+++ b/ip/Makefile

@@ -11,7 +11,7 @@ IPOBJ=ip.o ipaddress.o ipaddrlabel.o iproute.o iprule.o ipnetns.o \
     iplink_bridge.o iplink_bridge_slave.o ipfou.o iplink_ipvlan.o \
     iplink_geneve.o iplink_vrf.o iproute_lwtunnel.o ipmacsec.o ipila.o \
     ipvrf.o iplink_xstats.o ipseg6.o iplink_netdevsim.o iplink_rmnet.o \
-    ipnexthop.o ipmptcp.o iplink_bareudp.o
+    ipnexthop.o ipmptcp.o iplink_bareudp.o iplink_wwan.o
 
 RTMONOBJ=rtmon.o
 

diff --git a/ip/iplink.c b/ip/iplink.c
index 33b7be30..18b2ea25 100644
--- a/ip/iplink.c
+++ b/ip/iplink.c

@@ -56,7 +56,8 @@ void iplink_types_usage(void)
 		"          ipip | ipoib | ipvlan | ipvtap |\n"
 		"          macsec | macvlan | macvtap |\n"
 		"          netdevsim | nlmon | rmnet | sit | team | team_slave |\n"
-		"          vcan | veth | vlan | vrf | vti | vxcan | vxlan | xfrm }\n");
+		"          vcan | veth | vlan | vrf | vti | vxcan | vxlan | wwan |\n"
+		"          xfrm }\n");
 }
 
 void iplink_usage(void)

diff --git a/ip/iplink_wwan.c b/ip/iplink_wwan.c
new file mode 100644
index 00000000..3510477a
--- /dev/null
+++ b/ip/iplink_wwan.c

@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <stdio.h>
+#include <linux/netlink.h>
+#include <linux/wwan.h>
+
+#include "utils.h"
+#include "ip_common.h"
+
+static void print_explain(FILE *f)
+{
+	fprintf(f,
+		"Usage: ... wwan linkid LINKID\n"
+		"\n"
+		"Where: LINKID := 0-4294967295\n"
+	);
+}
+
+static void explain(void)
+{
+	print_explain(stderr);
+}
+
+static int wwan_parse_opt(struct link_util *lu, int argc, char **argv,
+			  struct nlmsghdr *n)
+{
+	while (argc > 0) {
+		if (matches(*argv, "linkid") == 0) {
+			__u32 linkid;
+
+			NEXT_ARG();
+			if (get_u32(&linkid, *argv, 0))
+				invarg("linkid", *argv);
+			addattr32(n, 1024, IFLA_WWAN_LINK_ID, linkid);
+		} else if (matches(*argv, "help") == 0) {
+			explain();
+			return -1;
+		} else {
+			fprintf(stderr, "wwan: unknown command \"%s\"?\n",
+				*argv);
+			explain();
+			return -1;
+		}
+		argc--, argv++;
+	}
+
+	return 0;
+}
+
+static void wwan_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
+{
+	if (!tb)
+		return;
+
+	if (tb[IFLA_WWAN_LINK_ID])
+		print_uint(PRINT_ANY, "linkid", "linkid %u ",
+			   rta_getattr_u32(tb[IFLA_WWAN_LINK_ID]));
+}
+
+static void wwan_print_help(struct link_util *lu, int argc, char **argv,
+			    FILE *f)
+{
+	print_explain(f);
+}
+
+struct link_util wwan_link_util = {
+	.id		= "wwan",
+	.maxattr	= IFLA_WWAN_MAX,
+	.parse_opt	= wwan_parse_opt,
+	.print_opt	= wwan_print_opt,
+	.print_help	= wwan_print_help,
+};

-- 
2.26.3

Hi Sergey,

On Tue, 22 Jun 2021 at 02:32, Sergey Ryazanov [off-list ref] wrote:

Parav suggested previously to simply name it 'parentbus'.

+                                    "parentdevbus %s ",
+                                    rta_getattr_str(tb[IFLA_PARENT_DEV_BUS_NAME]));
+               }
+
+               if (tb[IFLA_PARENT_DEV_NAME]) {
+                       print_string(PRINT_ANY,
+                                    "parentdev",
+                                    "parentdev %s ",
+                                    rta_getattr_str(tb[IFLA_PARENT_DEV_NAME]));
+               }
        }

On Tue, Jun 22, 2021 at 9:46 AM Loic Poulain [off-list ref] wrote:

On Tue, 22 Jun 2021 at 02:32, Sergey Ryazanov [off-list ref] wrote:

quoted

Add support for specifying a parent device (struct device) by its name
during the link creation and printing parent name in the links list.
This option will be used to create WWAN links and possibly by other
device classes that do not have a "natural parent netdev".

Add the parent device bus name printing for links list info
completeness. But do not add a corresponding command line argument, as
we do not have a use case for this attribute.

Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
---
 ip/ipaddress.c | 14 ++++++++++++++
 ip/iplink.c    |  6 +++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/ip/ipaddress.c b/ip/ipaddress.c
index 06ca7273..7dc38ff1 100644
--- a/ip/ipaddress.c
+++ b/ip/ipaddress.c

@@ -1242,6 +1242,20 @@ int print_linkinfo(struct nlmsghdr *n, void *arg)
                }
+
+               if (tb[IFLA_PARENT_DEV_BUS_NAME]) {
+                       print_string(PRINT_ANY,
+                                    "parentdevbus",

Parav suggested previously to simply name it 'parentbus'.

Khm. Sounds reasonable. Will do it in V3.

quoted

+                                    "parentdevbus %s ",
+                                    rta_getattr_str(tb[IFLA_PARENT_DEV_BUS_NAME]));
+               }
+
+               if (tb[IFLA_PARENT_DEV_NAME]) {
+                       print_string(PRINT_ANY,
+                                    "parentdev",
+                                    "parentdev %s ",
+                                    rta_getattr_str(tb[IFLA_PARENT_DEV_NAME]));
+               }
        }

-- 
Sergey