Re: [PATCH net-next v18 07/13] net: ethtool: Introduce a command to list PHYs on an interface
From: Eric Dumazet
Date: Tue Sep 10 2024 - 12:41:30 EST
On Wed, Aug 21, 2024 at 5:10 PM Maxime Chevallier
<maxime.chevallier@xxxxxxxxxxx> wrote:
>
> 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>
> Reviewed-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> Tested-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> ---
> 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 2d14b8551348..8c152871c23c 100644
> --- a/Documentation/networking/ethtool-netlink.rst
> +++ b/Documentation/networking/ethtool-netlink.rst
> @@ -2191,6 +2191,46 @@ 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
> ===================
>
> @@ -2298,4 +2338,5 @@ 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 49d1f9220fde..45d8bcdea056 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,
> @@ -1055,6 +1058,22 @@ 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 b00061924e80..e3f0ef6b851b 100644
> --- a/net/ethtool/netlink.c
> +++ b/net/ethtool/netlink.c
> @@ -1234,6 +1234,15 @@ 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 e326699405be..203b08eb6c6f 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);
> @@ -494,6 +495,10 @@ 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_rss_dump_start(struct netlink_callback *cb);
> int ethnl_rss_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..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 */
I got a syzbot report here.
Should we fix this with :
diff --git a/net/ethtool/phy.c b/net/ethtool/phy.c
index 560dd039c6625ac0925a0f28c14ce77cf768b6a5..4ef7c6e32d1087dc71acb467f9cd2ab8faf4dc39
100644
--- a/net/ethtool/phy.c
+++ b/net/ethtool/phy.c
@@ -164,7 +164,7 @@ int ethnl_phy_doit(struct sk_buff *skb, struct
genl_info *info)
goto err_unlock_rtnl;
/* No PHY, return early */
- if (!req_info.pdn->phy)
+ if (!req_info.pdn)
goto err_unlock_rtnl;
ret = ethnl_phy_reply_size(&req_info.base, info->extack);
> + 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;
> +}
> --
> 2.45.2
>