[GENETLINK]: Dynamic multicast groups. (2dbba6f7) · Commits · e / devices / android_kernel_xiaomi_markw

include/linux/genetlink.h

+13 −0

Original line number	Diff line number	Diff line
		@@ -39,6 +39,9 @@ enum {
		CTRL_CMD_NEWOPS,
		CTRL_CMD_DELOPS,
		CTRL_CMD_GETOPS,
		CTRL_CMD_NEWMCAST_GRP,
		CTRL_CMD_DELMCAST_GRP,
		CTRL_CMD_GETMCAST_GRP, /* unused */
		__CTRL_CMD_MAX,
		};

		@@ -52,6 +55,7 @@ enum {
		CTRL_ATTR_HDRSIZE,
		CTRL_ATTR_MAXATTR,
		CTRL_ATTR_OPS,
		CTRL_ATTR_MCAST_GROUPS,
		__CTRL_ATTR_MAX,
		};

		@@ -66,4 +70,13 @@ enum {

		#define CTRL_ATTR_OP_MAX (__CTRL_ATTR_OP_MAX - 1)

		enum {
		CTRL_ATTR_MCAST_GRP_UNSPEC,
		CTRL_ATTR_MCAST_GRP_NAME,
		CTRL_ATTR_MCAST_GRP_ID,
		__CTRL_ATTR_MCAST_GRP_MAX,
		};

		#define CTRL_ATTR_MCAST_GRP_MAX (__CTRL_ATTR_MCAST_GRP_MAX - 1)

		#endif /* __LINUX_GENERIC_NETLINK_H */

include/net/genetlink.h

+22 −0

Original line number	Diff line number	Diff line
		@@ -4,6 +4,22 @@
		#include <linux/genetlink.h>
		#include <net/netlink.h>

		/**
		* struct genl_multicast_group - generic netlink multicast group
		* @name: name of the multicast group, names are per-family
		* @id: multicast group ID, assigned by the core, to use with
		* genlmsg_multicast().
		* @list: list entry for linking
		* @family: pointer to family, need not be set before registering
		*/
		struct genl_multicast_group
		{
		struct genl_family family; / private */
		struct list_head list; /* private */
		char name[GENL_NAMSIZ];
		u32 id;
		};

		/**
		* struct genl_family - generic netlink family
		* @id: protocol family idenfitier
		@@ -14,6 +30,7 @@
		* @attrbuf: buffer to store parsed attributes
		* @ops_list: list of all assigned operations
		* @family_list: family list
		* @mcast_groups: multicast groups list
		*/
		struct genl_family
		{
		@@ -25,6 +42,7 @@ struct genl_family
		struct nlattr ** attrbuf; /* private */
		struct list_head ops_list; /* private */
		struct list_head family_list; /* private */
		struct list_head mcast_groups; /* private */
		};

		/**
		@@ -73,6 +91,10 @@ extern int genl_register_family(struct genl_family *family);
		extern int genl_unregister_family(struct genl_family *family);
		extern int genl_register_ops(struct genl_family , struct genl_ops ops);
		extern int genl_unregister_ops(struct genl_family , struct genl_ops ops);
		extern int genl_register_mc_group(struct genl_family *family,
		struct genl_multicast_group *grp);
		extern void genl_unregister_mc_group(struct genl_family *family,
		struct genl_multicast_group *grp);

		extern struct sock *genl_sock;

net/netlink/genetlink.c

+228 −7

Original line number	Diff line number	Diff line
		@@ -3,6 +3,7 @@
		*
		* Authors: Jamal Hadi Salim
		* Thomas Graf <tgraf@suug.ch>
		* Johannes Berg <johannes@sipsolutions.net>
		*/

		#include <linux/module.h>
		@@ -13,6 +14,7 @@
		#include <linux/string.h>
		#include <linux/skbuff.h>
		#include <linux/mutex.h>
		#include <linux/bitmap.h>
		#include <net/sock.h>
		#include <net/genetlink.h>

		@@ -42,6 +44,16 @@ static void genl_unlock(void)
		#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)

		static struct list_head family_ht[GENL_FAM_TAB_SIZE];
		/*
		* Bitmap of multicast groups that are currently in use.
		*
		* To avoid an allocation at boot of just one unsigned long,
		* declare it global instead.
		* Bit 0 is marked as already used since group 0 is invalid.
		*/
		static unsigned long mc_group_start = 0x1;
		static unsigned long *mc_groups = &mc_group_start;
		static unsigned long mc_groups_longs = 1;

		static int genl_ctrl_event(int event, void *data);

		@@ -116,6 +128,114 @@ static inline u16 genl_generate_id(void)
		return id_gen_idx;
		}

		static struct genl_multicast_group notify_grp;

		/**
		* genl_register_mc_group - register a multicast group
		*
		* Registers the specified multicast group and notifies userspace
		* about the new group.
		*
		* Returns 0 on success or a negative error code.
		*
		* @family: The generic netlink family the group shall be registered for.
		* @grp: The group to register, must have a name.
		*/
		int genl_register_mc_group(struct genl_family *family,
		struct genl_multicast_group *grp)
		{
		int id;
		unsigned long *new_groups;
		int err;

		BUG_ON(grp->name[0] == '\0');

		genl_lock();

		/* special-case our own group */
		if (grp == &notify_grp)
		id = GENL_ID_CTRL;
		else
		id = find_first_zero_bit(mc_groups,
		mc_groups_longs * BITS_PER_LONG);


		if (id >= mc_groups_longs * BITS_PER_LONG) {
		size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);

		if (mc_groups == &mc_group_start) {
		new_groups = kzalloc(nlen, GFP_KERNEL);
		if (!new_groups) {
		err = -ENOMEM;
		goto out;
		}
		mc_groups = new_groups;
		*mc_groups = mc_group_start;
		} else {
		new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
		if (!new_groups) {
		err = -ENOMEM;
		goto out;
		}
		mc_groups = new_groups;
		mc_groups[mc_groups_longs] = 0;
		}
		mc_groups_longs++;
		}

		err = netlink_change_ngroups(genl_sock,
		sizeof(unsigned long) * NETLINK_GENERIC);
		if (err)
		goto out;

		grp->id = id;
		set_bit(id, mc_groups);
		list_add_tail(&grp->list, &family->mcast_groups);
		grp->family = family;

		genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
		out:
		genl_unlock();
		return 0;
		}
		EXPORT_SYMBOL(genl_register_mc_group);

		/**
		* genl_unregister_mc_group - unregister a multicast group
		*
		* Unregisters the specified multicast group and notifies userspace
		* about it. All current listeners on the group are removed.
		*
		* Note: It is not necessary to unregister all multicast groups before
		* unregistering the family, unregistering the family will cause
		* all assigned multicast groups to be unregistered automatically.
		*
		* @family: Generic netlink family the group belongs to.
		* @grp: The group to unregister, must have been registered successfully
		* previously.
		*/
		void genl_unregister_mc_group(struct genl_family *family,
		struct genl_multicast_group *grp)
		{
		BUG_ON(grp->family != family);
		genl_lock();
		netlink_clear_multicast_users(genl_sock, grp->id);
		clear_bit(grp->id, mc_groups);
		list_del(&grp->list);
		genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
		grp->id = 0;
		grp->family = NULL;
		genl_unlock();
		}

		static void genl_unregister_mc_groups(struct genl_family *family)
		{
		struct genl_multicast_group grp, tmp;

		list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
		genl_unregister_mc_group(family, grp);
		}

		/**
		* genl_register_ops - register generic netlink operations
		* @family: generic netlink family
		@@ -216,6 +336,7 @@ int genl_register_family(struct genl_family *family)
		goto errout;

		INIT_LIST_HEAD(&family->ops_list);
		INIT_LIST_HEAD(&family->mcast_groups);

		genl_lock();

		@@ -275,6 +396,8 @@ int genl_unregister_family(struct genl_family *family)
		{
		struct genl_family *rc;

		genl_unregister_mc_groups(family);

		genl_lock();

		list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
		@@ -410,6 +533,67 @@ static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
		nla_nest_end(skb, nla_ops);
		}

		if (!list_empty(&family->mcast_groups)) {
		struct genl_multicast_group *grp;
		struct nlattr *nla_grps;
		int idx = 1;

		nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
		if (nla_grps == NULL)
		goto nla_put_failure;

		list_for_each_entry(grp, &family->mcast_groups, list) {
		struct nlattr *nest;

		nest = nla_nest_start(skb, idx++);
		if (nest == NULL)
		goto nla_put_failure;

		NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
		NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
		grp->name);

		nla_nest_end(skb, nest);
		}
		nla_nest_end(skb, nla_grps);
		}

		return genlmsg_end(skb, hdr);

		nla_put_failure:
		return genlmsg_cancel(skb, hdr);
		}

		static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
		u32 seq, u32 flags, struct sk_buff *skb,
		u8 cmd)
		{
		void *hdr;
		struct nlattr *nla_grps;
		struct nlattr *nest;

		hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
		if (hdr == NULL)
		return -1;

		NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
		NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);

		nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
		if (nla_grps == NULL)
		goto nla_put_failure;

		nest = nla_nest_start(skb, 1);
		if (nest == NULL)
		goto nla_put_failure;

		NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
		NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
		grp->name);

		nla_nest_end(skb, nest);
		nla_nest_end(skb, nla_grps);

		return genlmsg_end(skb, hdr);

		nla_put_failure:
		@@ -453,8 +637,8 @@ errout:
		return skb->len;
		}

		static struct sk_buff ctrl_build_msg(struct genl_family family, u32 pid,
		int seq, u8 cmd)
		static struct sk_buff ctrl_build_family_msg(struct genl_family family,
		u32 pid, int seq, u8 cmd)
		{
		struct sk_buff *skb;
		int err;
		@@ -472,6 +656,25 @@ static struct sk_buff ctrl_build_msg(struct genl_family family, u32 pid,
		return skb;
		}

		static struct sk_buff ctrl_build_mcgrp_msg(struct genl_multicast_group grp,
		u32 pid, int seq, u8 cmd)
		{
		struct sk_buff *skb;
		int err;

		skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
		if (skb == NULL)
		return ERR_PTR(-ENOBUFS);

		err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
		if (err < 0) {
		nlmsg_free(skb);
		return ERR_PTR(err);
		}

		return skb;
		}

		static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
		[CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
		[CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
		@@ -501,7 +704,7 @@ static int ctrl_getfamily(struct sk_buff skb, struct genl_info info)
		goto errout;
		}

		msg = ctrl_build_msg(res, info->snd_pid, info->snd_seq,
		msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
		CTRL_CMD_NEWFAMILY);
		if (IS_ERR(msg)) {
		err = PTR_ERR(msg);
		@@ -523,7 +726,15 @@ static int genl_ctrl_event(int event, void *data)
		switch (event) {
		case CTRL_CMD_NEWFAMILY:
		case CTRL_CMD_DELFAMILY:
		msg = ctrl_build_msg(data, 0, 0, event);
		msg = ctrl_build_family_msg(data, 0, 0, event);
		if (IS_ERR(msg))
		return PTR_ERR(msg);

		genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
		break;
		case CTRL_CMD_NEWMCAST_GRP:
		case CTRL_CMD_DELMCAST_GRP:
		msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
		if (IS_ERR(msg))
		return PTR_ERR(msg);

		@@ -541,6 +752,10 @@ static struct genl_ops genl_ctrl_ops = {
		.policy = ctrl_policy,
		};

		static struct genl_multicast_group notify_grp = {
		.name = "notify",
		};

		static int __init genl_init(void)
		{
		int i, err;
		@@ -557,11 +772,17 @@ static int __init genl_init(void)
		goto errout_register;

		netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
		genl_sock = netlink_kernel_create(NETLINK_GENERIC, GENL_MAX_ID,
		genl_rcv, NULL, THIS_MODULE);

		/* we'll bump the group number right afterwards */
		genl_sock = netlink_kernel_create(NETLINK_GENERIC, 0, genl_rcv,
		NULL, THIS_MODULE);
		if (genl_sock == NULL)
		panic("GENL: Cannot initialize generic netlink\n");

		err = genl_register_mc_group(&genl_ctrl, &notify_grp);
		if (err < 0)
		goto errout_register;

		return 0;

		errout_register: