Commit 42401c42 authored by Carolina Jubran's avatar Carolina Jubran Committed by Jakub Kicinski
Browse files

netlink: introduce type-checking attribute iteration for nlmsg 



Add the nlmsg_for_each_attr_type() macro to simplify iteration over
attributes of a specific type in a Netlink message.

Convert existing users in vxlan and nfsd to use the new macro.

Suggested-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarCarolina Jubran <cjubran@nvidia.com>
Signed-off-by: default avatarMark Bloch <mbloch@nvidia.com>
Link: https://patch.msgid.link/20250629142138.361537-2-mbloch@nvidia.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 97b2409f

drivers/net/vxlan/vxlan_vnifilter.c

+4 −9
Original line number Diff line number Diff line
@@ -971,15 +971,10 @@ static int vxlan_vnifilter_process(struct sk_buff *skb, struct nlmsghdr *nlh, 
	if (!(vxlan->cfg.flags & VXLAN_F_VNIFILTER))

		return -EOPNOTSUPP;



	nlmsg_for_each_attr(attr, nlh, sizeof(*tmsg), rem) {

		switch (nla_type(attr)) {

		case VXLAN_VNIFILTER_ENTRY:

			err = vxlan_process_vni_filter(vxlan, attr,

						       nlh->nlmsg_type, extack);

			break;

		default:

			continue;

		}

	nlmsg_for_each_attr_type(attr, VXLAN_VNIFILTER_ENTRY, nlh,

				 sizeof(*tmsg), rem) {

		err = vxlan_process_vni_filter(vxlan, attr, nlh->nlmsg_type,

					       extack);

		vnis++;

		if (err)

			break;

fs/nfsd/nfsctl.c

+14 −22
Original line number Diff line number Diff line
@@ -1621,10 +1621,9 @@ int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info) 
		return -EINVAL;



	/* count number of SERVER_THREADS values */

	nlmsg_for_each_attr(attr, info->nlhdr, GENL_HDRLEN, rem) {

		if (nla_type(attr) == NFSD_A_SERVER_THREADS)

	nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_THREADS, info->nlhdr,

				 GENL_HDRLEN, rem)

		nrpools++;

	}



	mutex_lock(&nfsd_mutex);
@@ -1635,13 +1634,12 @@ int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info) 
	}



	i = 0;

	nlmsg_for_each_attr(attr, info->nlhdr, GENL_HDRLEN, rem) {

		if (nla_type(attr) == NFSD_A_SERVER_THREADS) {

	nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_THREADS, info->nlhdr,

				 GENL_HDRLEN, rem) {

		nthreads[i++] = nla_get_u32(attr);

		if (i >= nrpools)

			break;

	}

	}



	if (info->attrs[NFSD_A_SERVER_GRACETIME] ||

	    info->attrs[NFSD_A_SERVER_LEASETIME] ||
@@ -1781,14 +1779,12 @@ int nfsd_nl_version_set_doit(struct sk_buff *skb, struct genl_info *info) 
	for (i = 0; i <= NFSD_SUPPORTED_MINOR_VERSION; i++)

		nfsd_minorversion(nn, i, NFSD_CLEAR);



	nlmsg_for_each_attr(attr, info->nlhdr, GENL_HDRLEN, rem) {

	nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_PROTO_VERSION, info->nlhdr,

				 GENL_HDRLEN, rem) {

		struct nlattr *tb[NFSD_A_VERSION_MAX + 1];

		u32 major, minor = 0;

		bool enabled;



		if (nla_type(attr) != NFSD_A_SERVER_PROTO_VERSION)

			continue;



		if (nla_parse_nested(tb, NFSD_A_VERSION_MAX, attr,

				     nfsd_version_nl_policy, info->extack) < 0)

			continue;
@@ -1939,14 +1935,12 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info) 
	 * Walk the list of server_socks from userland and move any that match

	 * back to sv_permsocks

	 */

	nlmsg_for_each_attr(attr, info->nlhdr, GENL_HDRLEN, rem) {

	nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_SOCK_ADDR, info->nlhdr,

				 GENL_HDRLEN, rem) {

		struct nlattr *tb[NFSD_A_SOCK_MAX + 1];

		const char *xcl_name;

		struct sockaddr *sa;



		if (nla_type(attr) != NFSD_A_SERVER_SOCK_ADDR)

			continue;



		if (nla_parse_nested(tb, NFSD_A_SOCK_MAX, attr,

				     nfsd_sock_nl_policy, info->extack) < 0)

			continue;
@@ -2001,15 +1995,13 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info) 
		svc_xprt_destroy_all(serv, net);



	/* walk list of addrs again, open any that still don't exist */

	nlmsg_for_each_attr(attr, info->nlhdr, GENL_HDRLEN, rem) {

	nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_SOCK_ADDR, info->nlhdr,

				 GENL_HDRLEN, rem) {

		struct nlattr *tb[NFSD_A_SOCK_MAX + 1];

		const char *xcl_name;

		struct sockaddr *sa;

		int ret;



		if (nla_type(attr) != NFSD_A_SERVER_SOCK_ADDR)

			continue;



		if (nla_parse_nested(tb, NFSD_A_SOCK_MAX, attr,

				     nfsd_sock_nl_policy, info->extack) < 0)

			continue;

include/net/netlink.h

+14 −0
Original line number Diff line number Diff line
@@ -68,6 +68,8 @@ 
 *   nlmsg_for_each_msg()		loop over all messages

 *   nlmsg_validate()			validate netlink message incl. attrs

 *   nlmsg_for_each_attr()		loop over all attributes

 *   nlmsg_for_each_attr_type()		loop over all attributes with the

 *					given type

 *

 * Misc:

 *   nlmsg_report()			report back to application?
@@ -966,6 +968,18 @@ static inline u32 nlmsg_seq(const struct nlmsghdr *nlh) 
	nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \

			  nlmsg_attrlen(nlh, hdrlen), rem)



/**

 * nlmsg_for_each_attr_type - iterate over a stream of attributes

 * @pos: loop counter, set to the current attribute

 * @type: required attribute type for @pos

 * @nlh: netlink message header

 * @hdrlen: length of the family specific header

 * @rem: initialized to len, holds bytes currently remaining in stream

 */

#define nlmsg_for_each_attr_type(pos, type, nlh, hdrlen, rem) \

	nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \

		if (nla_type(pos) == type)



/**

 * nlmsg_put - Add a new netlink message to an skb

 * @skb: socket buffer to store message in