diff mbox series

[RFC,iproute2-next] iplink: allow to change iplink value

Message ID 20210410133454.4768-5-ansuelsmth@gmail.com
State New
Headers show
Series Multi-CPU DSA support | expand

Commit Message

Christian Marangi April 10, 2021, 1:34 p.m. UTC 
Allow to change the interface to which a given interface is linked to.
This is useful in the case of multi-CPU port DSA, for changing the CPU
port of a given user port.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Cc: David Ahern <dsahern@gmail.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
---
 ip/iplink.c           | 16 +++++-----------
 man/man8/ip-link.8.in |  7 +++++++
 2 files changed, 12 insertions(+), 11 deletions(-)

Comments

Stephen Hemminger April 11, 2021, 5:04 p.m. UTC | #1 
On Sat, 10 Apr 2021 15:34:50 +0200
Ansuel Smith <ansuelsmth@gmail.com> wrote:

> Allow to change the interface to which a given interface is linked to.
> This is useful in the case of multi-CPU port DSA, for changing the CPU
> port of a given user port.
> 
> Signed-off-by: Marek Behún <marek.behun@nic.cz>
> Cc: David Ahern <dsahern@gmail.com>
> Cc: Stephen Hemminger <stephen@networkplumber.org>

This may work for DSA but it won't work for all the device types vlan/macsec/... that
now use the link attribute.  It looks like the change link handling for those
device types just ignores the link attribute (maybe ok). But before supporting this
as an API, it would be better if all the other drivers that use IFLA_LINK
had error checks in their change link handling.

Please add error checks in kernel first.
diff mbox series

Patch

diff --git a/ip/iplink.c b/ip/iplink.c
index 212a0885..d52c0aaf 100644
--- a/ip/iplink.c
+++ b/ip/iplink.c
@@ -579,7 +579,6 @@  int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
 {
 	char *name = NULL;
 	char *dev = NULL;
-	char *link = NULL;
 	int ret, len;
 	char abuf[32];
 	int qlen = -1;
@@ -590,6 +589,7 @@  int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
 	int numrxqueues = -1;
 	int link_netnsid = -1;
 	int index = 0;
+	int link = -1;
 	int group = -1;
 	int addr_len = 0;
 
@@ -620,7 +620,10 @@  int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
 				invarg("Invalid \"index\" value", *argv);
 		} else if (matches(*argv, "link") == 0) {
 			NEXT_ARG();
-			link = *argv;
+			link = ll_name_to_index(*argv);
+			if (!link)
+				return nodev(*argv);
+			addattr32(&req->n, sizeof(*req), IFLA_LINK, link);
 		} else if (matches(*argv, "address") == 0) {
 			NEXT_ARG();
 			addr_len = ll_addr_a2n(abuf, sizeof(abuf), *argv);
@@ -1004,15 +1007,6 @@  int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
 			exit(-1);
 		}
 
-		if (link) {
-			int ifindex;
-
-			ifindex = ll_name_to_index(link);
-			if (!ifindex)
-				return nodev(link);
-			addattr32(&req->n, sizeof(*req), IFLA_LINK, ifindex);
-		}
-
 		req->i.ifi_index = index;
 	}
 
diff --git a/man/man8/ip-link.8.in b/man/man8/ip-link.8.in
index a8ae72d2..800aed05 100644
--- a/man/man8/ip-link.8.in
+++ b/man/man8/ip-link.8.in
@@ -149,6 +149,9 @@  ip-link \- network device configuration
 .br
 .RB "[ " nomaster " ]"
 .br
+.RB "[ " link
+.IR DEVICE " ]"
+.br
 .RB "[ " vrf
 .IR NAME " ]"
 .br
@@ -2131,6 +2134,10 @@  set master device of the device (enslave device).
 .BI nomaster
 unset master device of the device (release device).
 
+.TP
+.BI link " DEVICE"
+set device to which this device is linked to.
+
 .TP
 .BI addrgenmode " eui64|none|stable_secret|random"
 set the IPv6 address generation mode