Re: [PATCH net-next v17 07/14] net: ethtool: Introduce a command to list PHYs on an interface

[Christophe Leroy <christophe.leroy@csgroup.eu>]

Le 09/07/2024 à 08:30, Maxime Chevallier a écrit :
> 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@bootlin.com>

Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu>

> ---
>   Documentation/networking/ethtool-netlink.rst |  41 +++
>   include/uapi/linux/ethtool_netlink.h         |  19 ++
>   net/ethtool/Makefile                         |   3 +-
>   net/ethtool/netlink.c                        |   9 +
>   net/ethtool/netlink.h                        |   5 +
>   net/ethtool/phy.c                            | 308 +++++++++++++++++++
>   6 files changed, 384 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 a6ea3716315f..d9f0c0dba1e5 100644
> --- a/Documentation/networking/ethtool-netlink.rst
> +++ b/Documentation/networking/ethtool-netlink.rst
> @@ -2182,6 +2182,46 @@ string.
>   The ``ETHTOOL_A_MODULE_FW_FLASH_DONE`` and ``ETHTOOL_A_MODULE_FW_FLASH_TOTAL``
>   attributes encode the completed and total amount of work, respectively.
>   
> +PHY_GET
> +=======
> +
> +Retrieve information about a given Ethernet PHY sitting on the link. The DO
> +operation returns all available information about dev->phydev. User can also
> +specify a PHY_INDEX, in which case the DO request returns information about that
> +specific PHY.
> +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
> +                                                its 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
> +  ===================================== ======  ===============================
> +
> +When ``ETHTOOL_A_PHY_UPSTREAM_TYPE`` is PHY_UPSTREAM_PHY, the PHY's parent is
> +another PHY.
> +
>   Request translation
>   ===================
>   
> @@ -2289,4 +2329,5 @@ are netlink only.
>     n/a                                 ``ETHTOOL_MSG_MM_GET``
>     n/a                                 ``ETHTOOL_MSG_MM_SET``
>     n/a                                 ``ETHTOOL_MSG_MODULE_FW_FLASH_ACT``
> +  n/a                                 ``ETHTOOL_MSG_PHY_GET``
>     =================================== =====================================
> diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
> index c5af23139e63..6ad32843b32a 100644
> --- a/include/uapi/linux/ethtool_netlink.h
> +++ b/include/uapi/linux/ethtool_netlink.h
> @@ -58,6 +58,7 @@ enum {
>   	ETHTOOL_MSG_MM_GET,
>   	ETHTOOL_MSG_MM_SET,
>   	ETHTOOL_MSG_MODULE_FW_FLASH_ACT,
> +	ETHTOOL_MSG_PHY_GET,
>   
>   	/* add new constants above here */
>   	__ETHTOOL_MSG_USER_CNT,
> @@ -111,6 +112,8 @@ enum {
>   	ETHTOOL_MSG_MM_GET_REPLY,
>   	ETHTOOL_MSG_MM_NTF,
>   	ETHTOOL_MSG_MODULE_FW_FLASH_NTF,
> +	ETHTOOL_MSG_PHY_GET_REPLY,
> +	ETHTOOL_MSG_PHY_NTF,
>   
>   	/* add new constants above here */
>   	__ETHTOOL_MSG_KERNEL_CNT,
> @@ -1050,6 +1053,22 @@ enum {
>   	ETHTOOL_A_MODULE_FW_FLASH_MAX = (__ETHTOOL_A_MODULE_FW_FLASH_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 */
> +
> +	/* 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 9a190635fe95..9b540644ba31 100644
> --- a/net/ethtool/Makefile
> +++ b/net/ethtool/Makefile
> @@ -8,4 +8,5 @@ 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 cmis_fw_update.o cmis_cdb.o pse-pd.o plca.o mm.o
> +		   module.o cmis_fw_update.o cmis_cdb.o pse-pd.o plca.o mm.o \
> +		   phy.o
> diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
> index 7b95571a6efb..153d34dbc48a 100644
> --- a/net/ethtool/netlink.c
> +++ b/net/ethtool/netlink.c
> @@ -1232,6 +1232,15 @@ static const struct genl_ops ethtool_genl_ops[] = {
>   		.policy	= ethnl_module_fw_flash_act_policy,
>   		.maxattr = ARRAY_SIZE(ethnl_module_fw_flash_act_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 4db16048f8d4..4a702dc853bf 100644
> --- a/net/ethtool/netlink.h
> +++ b/net/ethtool/netlink.h
> @@ -484,6 +484,7 @@ extern const struct nla_policy ethnl_plca_get_status_policy[ETHTOOL_A_PLCA_HEADE
>   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_module_fw_flash_act_policy[ETHTOOL_A_MODULE_FW_FLASH_PASSWORD + 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);
> @@ -492,6 +493,10 @@ 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_act_module_fw_flash(struct sk_buff *skb, struct genl_info *info);
> +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..560dd039c662
> --- /dev/null
> +++ b/net/ethtool/phy.c
> @@ -0,0 +1,308 @@
> +// 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));
> +
> +	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))
> +		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 netlink_ext_ack *extack)
> +{
> +	struct phy_link_topology *topo = req_base->dev->link_topo;
> +	struct phy_req_info *req_info = PHY_REQINFO(req_base);
> +	struct phy_device *phydev;
> +
> +	phydev = ethnl_req_get_phydev(req_base, tb[ETHTOOL_A_PHY_HEADER],
> +				      extack);
> +	if (!phydev)
> +		return 0;
> +
> +	if (IS_ERR(phydev))
> +		return PTR_ERR(phydev);
> +
> +	if (!topo)
> +		return 0;
> +
> +	req_info->pdn = xa_load(&topo->phys, phydev->phyindex);
> +
> +	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, info->extack);
> +	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_info *info = genl_info_dump(cb);
> +	struct ethnl_phy_dump_ctx *ctx = (void *)cb->ctx;
> +	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,
> +					 info->attrs[ETHTOOL_A_PHY_HEADER],
> +					 sock_net(cb->skb->sk), cb->extack,
> +					 false);
> +	ctx->ifindex = 0;
> +	ctx->phy_index = 0;
> +
> +	if (ret)
> +		kfree(ctx->phy_req_info);
> +
> +	return ret;
> +}
> +
> +int ethnl_phy_done(struct netlink_callback *cb)
> +{
> +	struct ethnl_phy_dump_ctx *ctx = (void *)cb->ctx;
> +
> +	if (ctx->phy_req_info->base.dev)
> +		ethnl_parse_header_dev_put(&ctx->phy_req_info->base);
> +
> +	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;
> +
> +	if (!dev->link_topo)
> +		return 0;
> +
> +	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;
> +		}
> +
> +		pri->pdn = pdn;
> +		ret = ethnl_phy_fill_reply(&pri->base, skb);
> +		if (ret < 0) {
> +			genlmsg_cancel(skb, ehdr);
> +			break;
> +		}
> +
> +		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);
> +	} 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();
> +
> +	return ret;
> +}