genetlink: Build a generic netlink family module alias (e9412c37) · Commits · 戴 / test

Generic netlink searches for -type- formatted aliases when requesting a module to fulfill a protocol request (i.e. net-pf-16-proto-16-type-<x>, where x is a type value). However generic netlink protocols have no well defined type numbers, they have string names. Modify genl_ctrl_getfamily to request an alias in the format net-pf-16-proto-16-family-<x> instead, where x is a generic string, and add a macro that builds on the previously added MODULE_ALIAS_NET_PF_PROTO_NAME macro to allow modules to specifify those generic strings. Note, l2tp previously hacked together an net-pf-16-proto-16-type-l2tp alias using the MODULE_ALIAS macro, with these updates we can convert that to use the PROTO_NAME macro. Signed-off-by:

Neil Horman <nhorman@tuxdriver.com> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: James Chapman <jchapman@katalix.com> CC: David Miller <davem@davemloft.net> Signed-off-by:

David S. Miller <davem@davemloft.net>

include/linux/genetlink.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -110,6 +110,9 @@ extern int lockdep_genl_is_held(void);
		#define genl_dereference(p) \
		rcu_dereference_protected(p, lockdep_genl_is_held())

		#define MODULE_ALIAS_GENL_FAMILY(family)\
		MODULE_ALIAS_NET_PF_PROTO_NAME(PF_NETLINK, NETLINK_GENERIC, "-family-" family)

		#endif /* __KERNEL__ */

		#endif /* __LINUX_GENERIC_NETLINK_H */

net/l2tp/l2tp_netlink.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -923,5 +923,4 @@ MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
		MODULE_DESCRIPTION("L2TP netlink");
		MODULE_LICENSE("GPL");
		MODULE_VERSION("1.0");
		MODULE_ALIAS("net-pf-" __stringify(PF_NETLINK) "-proto-" \
		__stringify(NETLINK_GENERIC) "-type-" "l2tp");
		MODULE_ALIAS_GENL_FAMILY("l2tp");

net/netlink/genetlink.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -836,7 +836,7 @@ static int ctrl_getfamily(struct sk_buff skb, struct genl_info info)
		#ifdef CONFIG_MODULES
		if (res == NULL) {
		genl_unlock();
		request_module("net-pf-%d-proto-%d-type-%s",
		request_module("net-pf-%d-proto-%d-family-%s",
		PF_NETLINK, NETLINK_GENERIC, name);
		genl_lock();
		res = genl_family_find_byname(name);

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