[PATCH net-next v5 01/22] rtnetlink: provide permanent hardware address in RTM_NEWLINK

Michal Kubecek
2019-03-25T17:10:59Z

Permanent hardware address of a network device was traditionally provided
via ethtool ioctl interface but as Jiri Pirko pointed out in a review of
ethtool netlink interface, rtnetlink is much more suitable for it so let's
add it to the RTM_NEWLINK message.

As permanent address is not modifiable, reject userspace requests
containing IFLA_PERM_ADDRESS attribute.

Note: we already provide permanent hardware address for bond slaves;
unfortunately we cannot drop that attribute for backward compatibility
reasons.

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
---
include/uapi/linux/if_link.h | 1 +
net/core/rtnetlink.c | 4 ++++
2 files changed, 5 insertions(+)

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 5b225ff63b48..351ef746b8b0 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -167,6 +167,7 @@ enum {
IFLA_NEW_IFINDEX,
IFLA_MIN_MTU,
IFLA_MAX_MTU,
+ IFLA_PERM_ADDRESS,
__IFLA_MAX
};

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index a51cab95ba64..a72e8f4d777b 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1026,6 +1026,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
+ nla_total_size(4) /* IFLA_CARRIER_DOWN_COUNT */
+ nla_total_size(4) /* IFLA_MIN_MTU */
+ nla_total_size(4) /* IFLA_MAX_MTU */
+ + nla_total_size(MAX_ADDR_LEN) /* IFLA_PERM_ADDRESS */
+ 0;
}

@@ -1683,6 +1684,8 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb,
nla_put_s32(skb, IFLA_NEW_IFINDEX, new_ifindex) < 0)
goto nla_put_failure;

+ if (nla_put(skb, IFLA_PERM_ADDRESS, dev->addr_len, dev->perm_addr))
+ goto nla_put_failure;

rcu_read_lock();
if (rtnl_fill_link_af(skb, dev, ext_filter_mask))
@@ -1742,6 +1745,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
[IFLA_CARRIER_DOWN_COUNT] = { .type = NLA_U32 },
[IFLA_MIN_MTU] = { .type = NLA_U32 },
[IFLA_MAX_MTU] = { .type = NLA_U32 },
+ [IFLA_PERM_ADDRESS] = { .type = NLA_REJECT },
};

static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
--
2.21.0