[PATCH net-next v6 07/13] net: ethtool: Introduce a command to list PHYs on an interface

From: Maxime Chevallier
Date: Fri Jan 26 2024 - 13:41:06 EST


As we have the ability to track the PHYs connected to a net_device
through the link_topology, we can expose this list to userspace. This
allows userspace to use these identifiers for phy-specific commands and
take the decision of which PHY to target by knowing the link topology.

Add PHY_GET and PHY_DUMP, which can be a filtered DUMP operation to list
devices on only one interface.

Signed-off-by: Maxime Chevallier <maxime.chevallier@xxxxxxxxxxx>
---
V6: - Removed un-needed nest
- Fixed the DUMP code
- Fixed the documentation formatting
V5: - Fixed xmas tree
- Fixed uninitialized return variable (Simon)
V4: - Fixed errors when not having SFP enabled, resulting in null names
being passed as parameters to strlen.
V3: - Fixed the documentation
- Fixed the DUMP implementation
V2: New patch

Documentation/networking/ethtool-netlink.rst | 39 +++
include/uapi/linux/ethtool_netlink.h | 20 ++
net/ethtool/Makefile | 2 +-
net/ethtool/netlink.c | 9 +
net/ethtool/netlink.h | 5 +
net/ethtool/phy.c | 298 +++++++++++++++++++
6 files changed, 372 insertions(+), 1 deletion(-)
create mode 100644 net/ethtool/phy.c

diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index 3ca6c21e74af..e498c3b0b28f 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -2011,6 +2011,44 @@ The attributes are propagated to the driver through the following structure:
.. kernel-doc:: include/linux/ethtool.h
:identifiers: ethtool_mm_cfg

+PHY_GET
+=======
+
+Retrieve information about a given Ethernet PHY sitting on the link. As there
+can be more than one PHY, the DUMP operation can be used to list the PHYs
+present on a given interface, by passing an interface index or name in
+the dump request
+
+Request contents:
+
+ ==================================== ====== ==========================
+ ``ETHTOOL_A_PHY_HEADER`` nested request header
+ ==================================== ====== ==========================
+
+Kernel response contents:
+
+ ===================================== ====== ===============================
+ ``ETHTOOL_A_PHY_HEADER`` nested request header
+ ``ETHTOOL_A_PHY_INDEX`` u32 the phy's unique index, that can
+ be used for phy-specific
+ requests
+ ``ETHTOOL_A_PHY_DRVNAME`` string the phy driver name
+ ``ETHTOOL_A_PHY_NAME`` string the phy device name
+ ``ETHTOOL_A_PHY_UPSTREAM_TYPE`` u32 the type of device this phy is
+ connected to
+ ``ETHTOOL_A_PHY_UPSTREAM_INDEX`` u32 the PHY index of the upstream
+ PHY
+ ``ETHTOOL_A_PHY_UPSTREAM_SFP_NAME`` string if this PHY is connected to
+ it's parent PHY through an SFP
+ bus, the name of this sfp bus
+ ``ETHTOOL_A_PHY_DOWNSTREAM_SFP_NAME`` string if the phy controls an sfp bus,
+ the name of the sfp bus
+ ``ETHTOOL_A_PHY_ID`` u32 the phy id if the phy is C22
+ ===================================== ====== ===============================
+
+When ``ETHTOOL_A_PHY_UPSTREAM_TYPE`` is PHY_UPSTREAM_PHY, the PHY's parent is
+another PHY.
+
Request translation
===================

@@ -2117,4 +2155,5 @@ are netlink only.
n/a ``ETHTOOL_MSG_PLCA_GET_STATUS``
n/a ``ETHTOOL_MSG_MM_GET``
n/a ``ETHTOOL_MSG_MM_SET``
+ n/a ``ETHTOOL_MSG_PHY_GET``
=================================== =====================================
diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index 422e8cfdd98c..f7a13e93ecb7 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -57,6 +57,7 @@ enum {
ETHTOOL_MSG_PLCA_GET_STATUS,
ETHTOOL_MSG_MM_GET,
ETHTOOL_MSG_MM_SET,
+ ETHTOOL_MSG_PHY_GET,

/* add new constants above here */
__ETHTOOL_MSG_USER_CNT,
@@ -109,6 +110,8 @@ enum {
ETHTOOL_MSG_PLCA_NTF,
ETHTOOL_MSG_MM_GET_REPLY,
ETHTOOL_MSG_MM_NTF,
+ ETHTOOL_MSG_PHY_GET_REPLY,
+ ETHTOOL_MSG_PHY_NTF,

/* add new constants above here */
__ETHTOOL_MSG_KERNEL_CNT,
@@ -977,6 +980,23 @@ enum {
ETHTOOL_A_MM_MAX = (__ETHTOOL_A_MM_CNT - 1)
};

+enum {
+ ETHTOOL_A_PHY_UNSPEC,
+ ETHTOOL_A_PHY_HEADER, /* nest - _A_HEADER_* */
+ ETHTOOL_A_PHY_INDEX, /* u32 */
+ ETHTOOL_A_PHY_DRVNAME, /* string */
+ ETHTOOL_A_PHY_NAME, /* string */
+ ETHTOOL_A_PHY_UPSTREAM_TYPE, /* u32 */
+ ETHTOOL_A_PHY_UPSTREAM_INDEX, /* u32 */
+ ETHTOOL_A_PHY_UPSTREAM_SFP_NAME, /* string */
+ ETHTOOL_A_PHY_DOWNSTREAM_SFP_NAME, /* string */
+ ETHTOOL_A_PHY_ID, /* u32 */
+
+ /* add new constants above here */
+ __ETHTOOL_A_PHY_CNT,
+ ETHTOOL_A_PHY_MAX = (__ETHTOOL_A_PHY_CNT - 1)
+};
+
/* generic netlink info */
#define ETHTOOL_GENL_NAME "ethtool"
#define ETHTOOL_GENL_VERSION 1
diff --git a/net/ethtool/Makefile b/net/ethtool/Makefile
index 504f954a1b28..0ccd0e9afd3f 100644
--- a/net/ethtool/Makefile
+++ b/net/ethtool/Makefile
@@ -8,4 +8,4 @@ ethtool_nl-y := netlink.o bitset.o strset.o linkinfo.o linkmodes.o rss.o \
linkstate.o debug.o wol.o features.o privflags.o rings.o \
channels.o coalesce.o pause.o eee.o tsinfo.o cabletest.o \
tunnels.o fec.o eeprom.o stats.o phc_vclocks.o mm.o \
- module.o pse-pd.o plca.o mm.o
+ module.o pse-pd.o plca.o mm.o phy.o
diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index 5a9beb09e5d4..6334e8ce95f7 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -1169,6 +1169,15 @@ static const struct genl_ops ethtool_genl_ops[] = {
.policy = ethnl_mm_set_policy,
.maxattr = ARRAY_SIZE(ethnl_mm_set_policy) - 1,
},
+ {
+ .cmd = ETHTOOL_MSG_PHY_GET,
+ .doit = ethnl_phy_doit,
+ .start = ethnl_phy_start,
+ .dumpit = ethnl_phy_dumpit,
+ .done = ethnl_phy_done,
+ .policy = ethnl_phy_get_policy,
+ .maxattr = ARRAY_SIZE(ethnl_phy_get_policy) - 1,
+ },
};

static const struct genl_multicast_group ethtool_nl_mcgrps[] = {
diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
index d57a890b5d9e..0e71b53bdb1c 100644
--- a/net/ethtool/netlink.h
+++ b/net/ethtool/netlink.h
@@ -446,6 +446,7 @@ extern const struct nla_policy ethnl_plca_set_cfg_policy[ETHTOOL_A_PLCA_MAX + 1]
extern const struct nla_policy ethnl_plca_get_status_policy[ETHTOOL_A_PLCA_HEADER + 1];
extern const struct nla_policy ethnl_mm_get_policy[ETHTOOL_A_MM_HEADER + 1];
extern const struct nla_policy ethnl_mm_set_policy[ETHTOOL_A_MM_MAX + 1];
+extern const struct nla_policy ethnl_phy_get_policy[ETHTOOL_A_PHY_HEADER + 1];

int ethnl_set_features(struct sk_buff *skb, struct genl_info *info);
int ethnl_act_cable_test(struct sk_buff *skb, struct genl_info *info);
@@ -453,6 +454,10 @@ int ethnl_act_cable_test_tdr(struct sk_buff *skb, struct genl_info *info);
int ethnl_tunnel_info_doit(struct sk_buff *skb, struct genl_info *info);
int ethnl_tunnel_info_start(struct netlink_callback *cb);
int ethnl_tunnel_info_dumpit(struct sk_buff *skb, struct netlink_callback *cb);
+int ethnl_phy_start(struct netlink_callback *cb);
+int ethnl_phy_doit(struct sk_buff *skb, struct genl_info *info);
+int ethnl_phy_dumpit(struct sk_buff *skb, struct netlink_callback *cb);
+int ethnl_phy_done(struct netlink_callback *cb);

extern const char stats_std_names[__ETHTOOL_STATS_CNT][ETH_GSTRING_LEN];
extern const char stats_eth_phy_names[__ETHTOOL_A_STATS_ETH_PHY_CNT][ETH_GSTRING_LEN];
diff --git a/net/ethtool/phy.c b/net/ethtool/phy.c
new file mode 100644
index 000000000000..116a60a2b1be
--- /dev/null
+++ b/net/ethtool/phy.c
@@ -0,0 +1,298 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2023 Bootlin
+ *
+ */
+#include "common.h"
+#include "netlink.h"
+
+#include <linux/phy.h>
+#include <linux/phy_link_topology.h>
+#include <linux/sfp.h>
+
+struct phy_req_info {
+ struct ethnl_req_info base;
+ struct phy_device_node pdn;
+};
+
+#define PHY_REQINFO(__req_base) \
+ container_of(__req_base, struct phy_req_info, base)
+
+const struct nla_policy ethnl_phy_get_policy[ETHTOOL_A_PHY_HEADER + 1] = {
+ [ETHTOOL_A_PHY_HEADER] = NLA_POLICY_NESTED(ethnl_header_policy),
+};
+
+/* Caller holds rtnl */
+static ssize_t
+ethnl_phy_reply_size(const struct ethnl_req_info *req_base,
+ struct netlink_ext_ack *extack)
+{
+ struct phy_req_info *req_info = PHY_REQINFO(req_base);
+ struct phy_device_node *pdn = &req_info->pdn;
+ struct phy_device *phydev = pdn->phy;
+ size_t size = 0;
+
+ ASSERT_RTNL();
+
+ /* ETHTOOL_A_PHY_INDEX */
+ size += nla_total_size(sizeof(u32));
+
+ /* ETHTOOL_A_DRVNAME */
+ if (phydev->drv)
+ size += nla_total_size(strlen(phydev->drv->name) + 1);
+
+ /* ETHTOOL_A_NAME */
+ size += nla_total_size(strlen(dev_name(&phydev->mdio.dev)) + 1);
+
+ /* ETHTOOL_A_PHY_UPSTREAM_TYPE */
+ size += nla_total_size(sizeof(u32));
+
+ /* ETHTOOL_A_PHY_ID */
+ size += nla_total_size(sizeof(u32));
+
+ if (phy_on_sfp(phydev)) {
+ const char *upstream_sfp_name = sfp_get_name(pdn->parent_sfp_bus);
+
+ /* ETHTOOL_A_PHY_UPSTREAM_SFP_NAME */
+ if (upstream_sfp_name)
+ size += nla_total_size(strlen(upstream_sfp_name) + 1);
+
+ /* ETHTOOL_A_PHY_UPSTREAM_INDEX */
+ size += nla_total_size(sizeof(u32));
+ }
+
+ /* ETHTOOL_A_PHY_DOWNSTREAM_SFP_NAME */
+ if (phydev->sfp_bus) {
+ const char *sfp_name = sfp_get_name(phydev->sfp_bus);
+
+ if (sfp_name)
+ size += nla_total_size(strlen(sfp_name) + 1);
+ }
+
+ return size;
+}
+
+static int
+ethnl_phy_fill_reply(const struct ethnl_req_info *req_base, struct sk_buff *skb)
+{
+ struct phy_req_info *req_info = PHY_REQINFO(req_base);
+ struct phy_device_node *pdn = &req_info->pdn;
+ struct phy_device *phydev = pdn->phy;
+ enum phy_upstream ptype;
+
+ ptype = pdn->upstream_type;
+
+ if (nla_put_u32(skb, ETHTOOL_A_PHY_INDEX, phydev->phyindex) ||
+ nla_put_string(skb, ETHTOOL_A_PHY_NAME, dev_name(&phydev->mdio.dev)) ||
+ nla_put_u32(skb, ETHTOOL_A_PHY_UPSTREAM_TYPE, ptype) ||
+ nla_put_u32(skb, ETHTOOL_A_PHY_ID, phydev->phy_id))
+ return -EMSGSIZE;
+
+ if (phydev->drv && nla_put_string(skb, ETHTOOL_A_PHY_DRVNAME, phydev->drv->name))
+ return -EMSGSIZE;
+
+ if (ptype == PHY_UPSTREAM_PHY) {
+ struct phy_device *upstream = pdn->upstream.phydev;
+ const char *sfp_upstream_name;
+
+ /* Parent index */
+ if (nla_put_u32(skb, ETHTOOL_A_PHY_UPSTREAM_INDEX, upstream->phyindex))
+ return -EMSGSIZE;
+
+ if (pdn->parent_sfp_bus) {
+ sfp_upstream_name = sfp_get_name(pdn->parent_sfp_bus);
+ if (sfp_upstream_name && nla_put_string(skb,
+ ETHTOOL_A_PHY_UPSTREAM_SFP_NAME,
+ sfp_upstream_name))
+ return -EMSGSIZE;
+ }
+ }
+
+ if (phydev->sfp_bus) {
+ const char *sfp_name = sfp_get_name(phydev->sfp_bus);
+
+ if (sfp_name &&
+ nla_put_string(skb, ETHTOOL_A_PHY_DOWNSTREAM_SFP_NAME,
+ sfp_name))
+ return -EMSGSIZE;
+ }
+
+ return 0;
+}
+
+static int ethnl_phy_parse_request(struct ethnl_req_info *req_base,
+ struct nlattr **tb)
+{
+ struct phy_link_topology *topo = req_base->dev->link_topo;
+ struct phy_req_info *req_info = PHY_REQINFO(req_base);
+ struct phy_device_node *pdn;
+
+ if (!req_base->phydev)
+ return 0;
+
+ pdn = xa_load(&topo->phys, req_base->phydev->phyindex);
+ memcpy(&req_info->pdn, pdn, sizeof(*pdn));
+
+ return 0;
+}
+
+int ethnl_phy_doit(struct sk_buff *skb, struct genl_info *info)
+{
+ struct phy_req_info req_info = {};
+ struct nlattr **tb = info->attrs;
+ struct sk_buff *rskb;
+ void *reply_payload;
+ int reply_len;
+ int ret;
+
+ ret = ethnl_parse_header_dev_get(&req_info.base,
+ tb[ETHTOOL_A_PHY_HEADER],
+ genl_info_net(info), info->extack,
+ true);
+ if (ret < 0)
+ return ret;
+
+ rtnl_lock();
+
+ ret = ethnl_phy_parse_request(&req_info.base, tb);
+ if (ret < 0)
+ goto err_unlock_rtnl;
+
+ /* No PHY, return early */
+ if (!req_info.pdn.phy)
+ goto err_unlock_rtnl;
+
+ ret = ethnl_phy_reply_size(&req_info.base, info->extack);
+ if (ret < 0)
+ goto err_unlock_rtnl;
+ reply_len = ret + ethnl_reply_header_size();
+
+ rskb = ethnl_reply_init(reply_len, req_info.base.dev,
+ ETHTOOL_MSG_PHY_GET_REPLY,
+ ETHTOOL_A_PHY_HEADER,
+ info, &reply_payload);
+ if (!rskb) {
+ ret = -ENOMEM;
+ goto err_unlock_rtnl;
+ }
+
+ ret = ethnl_phy_fill_reply(&req_info.base, rskb);
+ if (ret)
+ goto err_free_msg;
+
+ rtnl_unlock();
+ ethnl_parse_header_dev_put(&req_info.base);
+ genlmsg_end(rskb, reply_payload);
+
+ return genlmsg_reply(rskb, info);
+
+err_free_msg:
+ nlmsg_free(rskb);
+err_unlock_rtnl:
+ rtnl_unlock();
+ ethnl_parse_header_dev_put(&req_info.base);
+ return ret;
+}
+
+struct ethnl_phy_dump_ctx {
+ struct phy_req_info *phy_req_info;
+ unsigned long ifindex;
+ unsigned long phy_index;
+};
+
+int ethnl_phy_start(struct netlink_callback *cb)
+{
+ const struct genl_dumpit_info *info = genl_dumpit_info(cb);
+ struct ethnl_phy_dump_ctx *ctx = (void *)cb->ctx;
+ struct nlattr **tb = info->info.attrs;
+ int ret;
+
+ BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
+
+ ctx->phy_req_info = kzalloc(sizeof(*ctx->phy_req_info), GFP_KERNEL);
+ if (!ctx->phy_req_info)
+ return -ENOMEM;
+
+ ret = ethnl_parse_header_dev_get(&ctx->phy_req_info->base,
+ tb[ETHTOOL_A_PHY_HEADER],
+ sock_net(cb->skb->sk), cb->extack,
+ false);
+ ctx->ifindex = 0;
+ ctx->phy_index = 0;
+ return ret;
+}
+
+int ethnl_phy_done(struct netlink_callback *cb)
+{
+ struct ethnl_phy_dump_ctx *ctx = (void *)cb->ctx;
+
+ kfree(ctx->phy_req_info);
+
+ return 0;
+}
+
+static int ethnl_phy_dump_one_dev(struct sk_buff *skb, struct net_device *dev,
+ struct netlink_callback *cb)
+{
+ struct ethnl_phy_dump_ctx *ctx = (void *)cb->ctx;
+ struct phy_req_info *pri = ctx->phy_req_info;
+ struct phy_device_node *pdn;
+ int ret = 0;
+ void *ehdr;
+
+ pri->base.dev = dev;
+
+ xa_for_each_start(&dev->link_topo->phys, ctx->phy_index, pdn, ctx->phy_index) {
+ ehdr = ethnl_dump_put(skb, cb,
+ ETHTOOL_MSG_PHY_GET_REPLY);
+ if (!ehdr) {
+ ret = -EMSGSIZE;
+ break;
+ }
+
+ ret = ethnl_fill_reply_header(skb, dev,
+ ETHTOOL_A_PHY_HEADER);
+ if (ret < 0) {
+ genlmsg_cancel(skb, ehdr);
+ break;
+ }
+
+ memcpy(&pri->pdn, pdn, sizeof(*pdn));
+ ret = ethnl_phy_fill_reply(&pri->base, skb);
+
+ genlmsg_end(skb, ehdr);
+ }
+
+ return ret;
+}
+
+int ethnl_phy_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
+{
+ struct ethnl_phy_dump_ctx *ctx = (void *)cb->ctx;
+ struct net *net = sock_net(skb->sk);
+ struct net_device *dev;
+ int ret = 0;
+
+ rtnl_lock();
+
+ if (ctx->phy_req_info->base.dev) {
+ ret = ethnl_phy_dump_one_dev(skb, ctx->phy_req_info->base.dev, cb);
+ ethnl_parse_header_dev_put(&ctx->phy_req_info->base);
+ ctx->phy_req_info->base.dev = NULL;
+ } else {
+ for_each_netdev_dump(net, dev, ctx->ifindex) {
+ ret = ethnl_phy_dump_one_dev(skb, dev, cb);
+ if (ret)
+ break;
+
+ ctx->phy_index = 0;
+ }
+ }
+ rtnl_unlock();
+
+ if (ret == -EMSGSIZE && skb->len)
+ return skb->len;
+
+ return ret;
+}
+
--
2.43.0