[PATCH net-next v8 08/14] ethtool: set link settings with LINKINFO_SET request

From: Michal Kubecek
Date: Sun Dec 22 2019 - 18:46:01 EST


Implement LINKINFO_SET netlink request to set link settings queried by
LINKINFO_GET message.

Only physical port, phy MDIO address and MDI(-X) control can be set,
attempt to modify MDI(-X) status and transceiver is rejected.

Signed-off-by: Michal Kubecek <mkubecek@xxxxxxx>
---
Documentation/networking/ethtool-netlink.rst | 24 ++++++-
include/uapi/linux/ethtool_netlink.h | 1 +
net/ethtool/linkinfo.c | 71 ++++++++++++++++++++
net/ethtool/netlink.c | 5 ++
net/ethtool/netlink.h | 2 +
5 files changed, 101 insertions(+), 2 deletions(-)

diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index 3460d6e31b82..e16ef058404f 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -171,6 +171,7 @@ Userspace to kernel:
===================================== ================================
``ETHTOOL_MSG_STRSET_GET`` get string set
``ETHTOOL_MSG_LINKINFO_GET`` get link settings
+ ``ETHTOOL_MSG_LINKINFO_SET`` set link settings
===================================== ================================

Kernel to userspace:
@@ -301,6 +302,25 @@ corresponding ioctl structures.
devices supporting the request).


+LINKINFO_SET
+============
+
+``LINKINFO_SET`` request allows setting some of the attributes reported by
+``LINKINFO_GET``.
+
+Request contents:
+
+ ==================================== ====== ==========================
+ ``ETHTOOL_A_LINKINFO_HEADER`` nested request header
+ ``ETHTOOL_A_LINKINFO_PORT`` u8 physical port
+ ``ETHTOOL_A_LINKINFO_PHYADDR`` u8 phy MDIO address
+ ``ETHTOOL_A_LINKINFO_TP_MDIX_CTRL`` u8 MDI(-X) control
+ ==================================== ====== ==========================
+
+MDI(-X) status and transceiver cannot be set, request with the corresponding
+attributes is rejected.
+
+
Request translation
===================

@@ -312,7 +332,7 @@ have their netlink replacement yet.
ioctl command netlink command
=================================== =====================================
``ETHTOOL_GSET`` ``ETHTOOL_MSG_LINKINFO_GET``
- ``ETHTOOL_SSET`` n/a
+ ``ETHTOOL_SSET`` ``ETHTOOL_MSG_LINKINFO_SET``
``ETHTOOL_GDRVINFO`` n/a
``ETHTOOL_GREGS`` n/a
``ETHTOOL_GWOL`` n/a
@@ -386,7 +406,7 @@ have their netlink replacement yet.
``ETHTOOL_GPHYSTATS`` n/a
``ETHTOOL_PERQUEUE`` n/a
``ETHTOOL_GLINKSETTINGS`` ``ETHTOOL_MSG_LINKINFO_GET``
- ``ETHTOOL_SLINKSETTINGS`` n/a
+ ``ETHTOOL_SLINKSETTINGS`` ``ETHTOOL_MSG_LINKINFO_SET``
``ETHTOOL_PHY_GTUNABLE`` n/a
``ETHTOOL_PHY_STUNABLE`` n/a
``ETHTOOL_GFECPARAM`` n/a
diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index 1966532993e5..5b7806a5bef8 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -16,6 +16,7 @@ enum {
ETHTOOL_MSG_USER_NONE,
ETHTOOL_MSG_STRSET_GET,
ETHTOOL_MSG_LINKINFO_GET,
+ ETHTOOL_MSG_LINKINFO_SET,

/* add new constants above here */
__ETHTOOL_MSG_USER_CNT,
diff --git a/net/ethtool/linkinfo.c b/net/ethtool/linkinfo.c
index f52a31af6fff..8a5f68f92425 100644
--- a/net/ethtool/linkinfo.c
+++ b/net/ethtool/linkinfo.c
@@ -92,3 +92,74 @@ const struct ethnl_request_ops ethnl_linkinfo_request_ops = {
.reply_size = linkinfo_reply_size,
.fill_reply = linkinfo_fill_reply,
};
+
+/* LINKINFO_SET */
+
+static const struct nla_policy
+linkinfo_set_policy[ETHTOOL_A_LINKINFO_MAX + 1] = {
+ [ETHTOOL_A_LINKINFO_UNSPEC] = { .type = NLA_REJECT },
+ [ETHTOOL_A_LINKINFO_HEADER] = { .type = NLA_NESTED },
+ [ETHTOOL_A_LINKINFO_PORT] = { .type = NLA_U8 },
+ [ETHTOOL_A_LINKINFO_PHYADDR] = { .type = NLA_U8 },
+ [ETHTOOL_A_LINKINFO_TP_MDIX] = { .type = NLA_REJECT },
+ [ETHTOOL_A_LINKINFO_TP_MDIX_CTRL] = { .type = NLA_U8 },
+ [ETHTOOL_A_LINKINFO_TRANSCEIVER] = { .type = NLA_REJECT },
+};
+
+int ethnl_set_linkinfo(struct sk_buff *skb, struct genl_info *info)
+{
+ struct nlattr *tb[ETHTOOL_A_LINKINFO_MAX + 1];
+ struct ethtool_link_ksettings ksettings = {};
+ struct ethtool_link_settings *lsettings;
+ struct ethnl_req_info req_info = {};
+ struct net_device *dev;
+ bool mod = false;
+ int ret;
+
+ ret = nlmsg_parse(info->nlhdr, GENL_HDRLEN, tb,
+ ETHTOOL_A_LINKINFO_MAX, linkinfo_set_policy,
+ info->extack);
+ if (ret < 0)
+ return ret;
+ ret = ethnl_parse_header(&req_info, tb[ETHTOOL_A_LINKINFO_HEADER],
+ genl_info_net(info), info->extack, true);
+ if (ret < 0)
+ return ret;
+ dev = req_info.dev;
+ if (!dev->ethtool_ops->get_link_ksettings ||
+ !dev->ethtool_ops->set_link_ksettings)
+ return -EOPNOTSUPP;
+
+ rtnl_lock();
+ ret = ethnl_ops_begin(dev);
+ if (ret < 0)
+ goto out_rtnl;
+
+ ret = __ethtool_get_link_ksettings(dev, &ksettings);
+ if (ret < 0) {
+ if (info)
+ GENL_SET_ERR_MSG(info, "failed to retrieve link settings");
+ goto out_ops;
+ }
+ lsettings = &ksettings.base;
+
+ ethnl_update_u8(&lsettings->port, tb[ETHTOOL_A_LINKINFO_PORT], &mod);
+ ethnl_update_u8(&lsettings->phy_address, tb[ETHTOOL_A_LINKINFO_PHYADDR],
+ &mod);
+ ethnl_update_u8(&lsettings->eth_tp_mdix_ctrl,
+ tb[ETHTOOL_A_LINKINFO_TP_MDIX_CTRL], &mod);
+ ret = 0;
+ if (!mod)
+ goto out_ops;
+
+ ret = dev->ethtool_ops->set_link_ksettings(dev, &ksettings);
+ if (ret < 0)
+ GENL_SET_ERR_MSG(info, "link settings update failed");
+
+out_ops:
+ ethnl_ops_complete(dev);
+out_rtnl:
+ rtnl_unlock();
+ dev_put(dev);
+ return ret;
+}
diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index ce86d97c922e..7867425956f6 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -534,6 +534,11 @@ static const struct genl_ops ethtool_genl_ops[] = {
.dumpit = ethnl_default_dumpit,
.done = ethnl_default_done,
},
+ {
+ .cmd = ETHTOOL_MSG_LINKINFO_SET,
+ .flags = GENL_UNS_ADMIN_PERM,
+ .doit = ethnl_set_linkinfo,
+ },
};

static const struct genl_multicast_group ethtool_nl_mcgrps[] = {
diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
index b2f4a49ae837..3448029e3ea2 100644
--- a/net/ethtool/netlink.h
+++ b/net/ethtool/netlink.h
@@ -331,4 +331,6 @@ struct ethnl_request_ops {
extern const struct ethnl_request_ops ethnl_strset_request_ops;
extern const struct ethnl_request_ops ethnl_linkinfo_request_ops;

+int ethnl_set_linkinfo(struct sk_buff *skb, struct genl_info *info);
+
#endif /* _NET_ETHTOOL_NETLINK_H */
--
2.24.1