Currently, there is no straightforward way to obtain the master/slave relationship via netlink. Users have to retrieve all slaves through sysfs to determine these relationships.
To address this, we can either list all slaves under the bond interface or display the master index in each slave. Since the number of slaves could be quite large (e.g., 100+), it is more efficient to show the master information in the slave entry.
Signed-off-by: Hangbin Liu liuhangbin@gmail.com --- drivers/net/bonding/bond_netlink.c | 4 ++++ include/uapi/linux/if_link.h | 1 + 2 files changed, 5 insertions(+)
diff --git a/drivers/net/bonding/bond_netlink.c b/drivers/net/bonding/bond_netlink.c index 286f11c517f7..ff3f11674a8b 100644 --- a/drivers/net/bonding/bond_netlink.c +++ b/drivers/net/bonding/bond_netlink.c @@ -29,6 +29,7 @@ static size_t bond_get_slave_size(const struct net_device *bond_dev, nla_total_size(sizeof(u16)) + /* IFLA_BOND_SLAVE_AD_PARTNER_OPER_PORT_STATE */ nla_total_size(sizeof(s32)) + /* IFLA_BOND_SLAVE_PRIO */ nla_total_size(sizeof(u16)) + /* IFLA_BOND_SLAVE_ACTOR_PORT_PRIO */ + nla_total_size(sizeof(u32)) + /* IFLA_BOND_SLAVE_MASTER */ 0; }
@@ -38,6 +39,9 @@ static int bond_fill_slave_info(struct sk_buff *skb, { struct slave *slave = bond_slave_get_rtnl(slave_dev);
+ if (nla_put_u32(skb, IFLA_BOND_SLAVE_MASTER, bond_dev->ifindex)) + goto nla_put_failure; + if (nla_put_u8(skb, IFLA_BOND_SLAVE_STATE, bond_slave_state(slave))) goto nla_put_failure;
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h index 3b491d96e52e..bad41a1807f7 100644 --- a/include/uapi/linux/if_link.h +++ b/include/uapi/linux/if_link.h @@ -1567,6 +1567,7 @@ enum { IFLA_BOND_SLAVE_AD_PARTNER_OPER_PORT_STATE, IFLA_BOND_SLAVE_PRIO, IFLA_BOND_SLAVE_ACTOR_PORT_PRIO, + IFLA_BOND_SLAVE_MASTER, __IFLA_BOND_SLAVE_MAX, };
Add a new attribute to display the name of the master interface for each slave.
Signed-off-by: Hangbin Liu liuhangbin@gmail.com --- ip/iplink_bond_slave.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/ip/iplink_bond_slave.c b/ip/iplink_bond_slave.c index c88100e248dd..55deaadf5fe2 100644 --- a/ip/iplink_bond_slave.c +++ b/ip/iplink_bond_slave.c @@ -92,6 +92,17 @@ static void bond_slave_print_opt(struct link_util *lu, FILE *f, struct rtattr *t if (!tb) return;
+ if (tb[IFLA_BOND_SLAVE_MASTER]) { + unsigned int ifindex = rta_getattr_u32(tb[IFLA_BOND_SLAVE_MASTER]); + + if (ifindex) { + print_string(PRINT_ANY, + "master", + "master %s ", + ll_index_to_name(ifindex)); + } + } + if (tb[IFLA_BOND_SLAVE_STATE]) print_slave_state(f, tb[IFLA_BOND_SLAVE_STATE]);
On Fri, 17 Oct 2025 03:05:09 +0000 Hangbin Liu liuhangbin@gmail.com wrote:
diff --git a/ip/iplink_bond_slave.c b/ip/iplink_bond_slave.c index c88100e248dd..55deaadf5fe2 100644 --- a/ip/iplink_bond_slave.c +++ b/ip/iplink_bond_slave.c @@ -92,6 +92,17 @@ static void bond_slave_print_opt(struct link_util *lu, FILE *f, struct rtattr *t if (!tb) return;
- if (tb[IFLA_BOND_SLAVE_MASTER]) {
unsigned int ifindex = rta_getattr_u32(tb[IFLA_BOND_SLAVE_MASTER]);if (ifindex) {print_string(PRINT_ANY,"master","master %s ",ll_index_to_name(ifindex));}- }
You should use print_color_string(PRINT_ANY, COLOR_IFNAME, ...) here
On 10/17/25 06:03, Hangbin Liu wrote:
Currently, there is no straightforward way to obtain the master/slave relationship via netlink. Users have to retrieve all slaves through sysfs to determine these relationships.
How about IFLA_MASTER? Why not use that?
To address this, we can either list all slaves under the bond interface or display the master index in each slave. Since the number of slaves could be quite large (e.g., 100+), it is more efficient to show the master information in the slave entry.
Signed-off-by: Hangbin Liu liuhangbin@gmail.com
drivers/net/bonding/bond_netlink.c | 4 ++++ include/uapi/linux/if_link.h | 1 + 2 files changed, 5 insertions(+)
diff --git a/drivers/net/bonding/bond_netlink.c b/drivers/net/bonding/bond_netlink.c index 286f11c517f7..ff3f11674a8b 100644 --- a/drivers/net/bonding/bond_netlink.c +++ b/drivers/net/bonding/bond_netlink.c @@ -29,6 +29,7 @@ static size_t bond_get_slave_size(const struct net_device *bond_dev, nla_total_size(sizeof(u16)) + /* IFLA_BOND_SLAVE_AD_PARTNER_OPER_PORT_STATE */ nla_total_size(sizeof(s32)) + /* IFLA_BOND_SLAVE_PRIO */ nla_total_size(sizeof(u16)) + /* IFLA_BOND_SLAVE_ACTOR_PORT_PRIO */
nla_total_size(sizeof(u32)) + /* IFLA_BOND_SLAVE_MASTER */} @@ -38,6 +39,9 @@ static int bond_fill_slave_info(struct sk_buff *skb, { struct slave *slave = bond_slave_get_rtnl(slave_dev);
- if (nla_put_u32(skb, IFLA_BOND_SLAVE_MASTER, bond_dev->ifindex))
goto nla_put_failure;- if (nla_put_u8(skb, IFLA_BOND_SLAVE_STATE, bond_slave_state(slave))) goto nla_put_failure;
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h index 3b491d96e52e..bad41a1807f7 100644 --- a/include/uapi/linux/if_link.h +++ b/include/uapi/linux/if_link.h @@ -1567,6 +1567,7 @@ enum { IFLA_BOND_SLAVE_AD_PARTNER_OPER_PORT_STATE, IFLA_BOND_SLAVE_PRIO, IFLA_BOND_SLAVE_ACTOR_PORT_PRIO,
- IFLA_BOND_SLAVE_MASTER, __IFLA_BOND_SLAVE_MAX,
};
On Fri, Oct 17, 2025 at 09:10:09AM +0300, Nikolay Aleksandrov wrote:
On 10/17/25 06:03, Hangbin Liu wrote:
Currently, there is no straightforward way to obtain the master/slave relationship via netlink. Users have to retrieve all slaves through sysfs to determine these relationships.
How about IFLA_MASTER? Why not use that?
Ah, I didn't notice this. We can show the master info directly with this...
# ip link show dummy0 3: dummy0: <BROADCAST,NOARP,SLAVE,UP,LOWER_UP> mtu 1500 qdisc noqueue master bond0 ...
Please ignore this patch.
Thanks Hangbin
Fri, Oct 17, 2025 at 08:10:09AM +0200, razor@blackwall.org wrote:
On 10/17/25 06:03, Hangbin Liu wrote:
Currently, there is no straightforward way to obtain the master/slave relationship via netlink. Users have to retrieve all slaves through sysfs to determine these relationships.
How about IFLA_MASTER? Why not use that?
It's been there for a decade. Plus is, it exposes master for all slave-master devices. Odd that you missed it.
On Fri, Oct 17, 2025 at 11:56:55AM +0200, Jiri Pirko wrote:
Fri, Oct 17, 2025 at 08:10:09AM +0200, razor@blackwall.org wrote:
On 10/17/25 06:03, Hangbin Liu wrote:
Currently, there is no straightforward way to obtain the master/slave relationship via netlink. Users have to retrieve all slaves through sysfs to determine these relationships.
How about IFLA_MASTER? Why not use that?
It's been there for a decade. Plus is, it exposes master for all slave-master devices. Odd that you missed it.
Once, I wanted to find the slaves from a master interface but couldn’t. So I added it to my to-do list. Later, I noticed that the master information was already available in the slave, but I forgot about it after long time. Recently, when I reviewed my to-do list, I realized that printing all slaves from the master interface seemed impractical. So I tried to list the master information in the slave again — and forgot about IFLA_MASTER...
Hangbin
linux-kselftest-mirror@lists.linaro.org
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Hangbin Liu -
Jiri Pirko -
Nikolay Aleksandrov -
Stephen Hemminger