From 041b1c5d4a53e97fc9e029ae32469552ca12cb9b Mon Sep 17 00:00:00 2001 From: Michal Kubecek Date: Fri, 27 Dec 2019 15:55:23 +0100 Subject: ethtool: helper functions for netlink interface Add common request/reply header definition and helpers to parse request header and fill reply header. Provide ethnl_update_* helpers to update structure members from request attributes (to be used for *_SET requests). Signed-off-by: Michal Kubecek Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller --- net/ethtool/netlink.h | 205 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 205 insertions(+) (limited to 'net/ethtool/netlink.h') diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h index e4220780d368..05d7183da894 100644 --- a/net/ethtool/netlink.h +++ b/net/ethtool/netlink.h @@ -6,5 +6,210 @@ #include #include #include +#include + +struct ethnl_req_info; + +int ethnl_parse_header(struct ethnl_req_info *req_info, + const struct nlattr *nest, struct net *net, + struct netlink_ext_ack *extack, bool require_dev); +int ethnl_fill_reply_header(struct sk_buff *skb, struct net_device *dev, + u16 attrtype); +struct sk_buff *ethnl_reply_init(size_t payload, struct net_device *dev, u8 cmd, + u16 hdr_attrtype, struct genl_info *info, + void **ehdrp); + +/** + * ethnl_strz_size() - calculate attribute length for fixed size string + * @s: ETH_GSTRING_LEN sized string (may not be null terminated) + * + * Return: total length of an attribute with null terminated string from @s + */ +static inline int ethnl_strz_size(const char *s) +{ + return nla_total_size(strnlen(s, ETH_GSTRING_LEN) + 1); +} + +/** + * ethnl_put_strz() - put string attribute with fixed size string + * @skb: skb with the message + * @attrype: attribute type + * @s: ETH_GSTRING_LEN sized string (may not be null terminated) + * + * Puts an attribute with null terminated string from @s into the message. + * + * Return: 0 on success, negative error code on failure + */ +static inline int ethnl_put_strz(struct sk_buff *skb, u16 attrtype, + const char *s) +{ + unsigned int len = strnlen(s, ETH_GSTRING_LEN); + struct nlattr *attr; + + attr = nla_reserve(skb, attrtype, len + 1); + if (!attr) + return -EMSGSIZE; + + memcpy(nla_data(attr), s, len); + ((char *)nla_data(attr))[len] = '\0'; + return 0; +} + +/** + * ethnl_update_u32() - update u32 value from NLA_U32 attribute + * @dst: value to update + * @attr: netlink attribute with new value or null + * @mod: pointer to bool for modification tracking + * + * Copy the u32 value from NLA_U32 netlink attribute @attr into variable + * pointed to by @dst; do nothing if @attr is null. Bool pointed to by @mod + * is set to true if this function changed the value of *dst, otherwise it + * is left as is. + */ +static inline void ethnl_update_u32(u32 *dst, const struct nlattr *attr, + bool *mod) +{ + u32 val; + + if (!attr) + return; + val = nla_get_u32(attr); + if (*dst == val) + return; + + *dst = val; + *mod = true; +} + +/** + * ethnl_update_u8() - update u8 value from NLA_U8 attribute + * @dst: value to update + * @attr: netlink attribute with new value or null + * @mod: pointer to bool for modification tracking + * + * Copy the u8 value from NLA_U8 netlink attribute @attr into variable + * pointed to by @dst; do nothing if @attr is null. Bool pointed to by @mod + * is set to true if this function changed the value of *dst, otherwise it + * is left as is. + */ +static inline void ethnl_update_u8(u8 *dst, const struct nlattr *attr, + bool *mod) +{ + u8 val; + + if (!attr) + return; + val = nla_get_u8(attr); + if (*dst == val) + return; + + *dst = val; + *mod = true; +} + +/** + * ethnl_update_bool32() - update u32 used as bool from NLA_U8 attribute + * @dst: value to update + * @attr: netlink attribute with new value or null + * @mod: pointer to bool for modification tracking + * + * Use the u8 value from NLA_U8 netlink attribute @attr to set u32 variable + * pointed to by @dst to 0 (if zero) or 1 (if not); do nothing if @attr is + * null. Bool pointed to by @mod is set to true if this function changed the + * logical value of *dst, otherwise it is left as is. + */ +static inline void ethnl_update_bool32(u32 *dst, const struct nlattr *attr, + bool *mod) +{ + u8 val; + + if (!attr) + return; + val = !!nla_get_u8(attr); + if (!!*dst == val) + return; + + *dst = val; + *mod = true; +} + +/** + * ethnl_update_binary() - update binary data from NLA_BINARY atribute + * @dst: value to update + * @len: destination buffer length + * @attr: netlink attribute with new value or null + * @mod: pointer to bool for modification tracking + * + * Use the u8 value from NLA_U8 netlink attribute @attr to rewrite data block + * of length @len at @dst by attribute payload; do nothing if @attr is null. + * Bool pointed to by @mod is set to true if this function changed the logical + * value of *dst, otherwise it is left as is. + */ +static inline void ethnl_update_binary(void *dst, unsigned int len, + const struct nlattr *attr, bool *mod) +{ + if (!attr) + return; + if (nla_len(attr) < len) + len = nla_len(attr); + if (!memcmp(dst, nla_data(attr), len)) + return; + + memcpy(dst, nla_data(attr), len); + *mod = true; +} + +/** + * ethnl_update_bitfield32() - update u32 value from NLA_BITFIELD32 attribute + * @dst: value to update + * @attr: netlink attribute with new value or null + * @mod: pointer to bool for modification tracking + * + * Update bits in u32 value which are set in attribute's mask to values from + * attribute's value. Do nothing if @attr is null or the value wouldn't change; + * otherwise, set bool pointed to by @mod to true. + */ +static inline void ethnl_update_bitfield32(u32 *dst, const struct nlattr *attr, + bool *mod) +{ + struct nla_bitfield32 change; + u32 newval; + + if (!attr) + return; + change = nla_get_bitfield32(attr); + newval = (*dst & ~change.selector) | (change.value & change.selector); + if (*dst == newval) + return; + + *dst = newval; + *mod = true; +} + +/** + * ethnl_reply_header_size() - total size of reply header + * + * This is an upper estimate so that we do not need to hold RTNL lock longer + * than necessary (to prevent rename between size estimate and composing the + * message). Accounts only for device ifindex and name as those are the only + * attributes ethnl_fill_reply_header() puts into the reply header. + */ +static inline unsigned int ethnl_reply_header_size(void) +{ + return nla_total_size(nla_total_size(sizeof(u32)) + + nla_total_size(IFNAMSIZ)); +} + +/** + * struct ethnl_req_info - base type of request information for GET requests + * @dev: network device the request is for (may be null) + * @flags: request flags common for all request types + * + * This is a common base, additional members may follow after this structure. + */ +struct ethnl_req_info { + struct net_device *dev; + u32 flags; +}; #endif /* _NET_ETHTOOL_NETLINK_H */ -- cgit v1.2.3-59-g8ed1b