Commit 50a896cf authored by Johannes Berg's avatar Johannes Berg Committed by David S. Miller
Browse files

genetlink: properly support per-op policy dumping 



Add support for per-op policy dumping. The data is pretty much
as before, except that now the assumption that the policy with
index 0 is "the" policy no longer holds - you now need to look
at the new CTRL_ATTR_OP_POLICY attribute which is a nested attr
(indexed by op) containing attributes for do and dump policies.

When a single op is requested, the CTRL_ATTR_OP_POLICY will be
added in the same way, since do and dump policies may differ.

v2:
 - conditionally advertise per-command policies only if there
   actually is a policy being used for the do/dump and it's
   present at all

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent aa85ee5f

include/uapi/linux/genetlink.h

+10 −0
Original line number Diff line number Diff line
@@ -64,6 +64,7 @@ enum { 
	CTRL_ATTR_OPS,

	CTRL_ATTR_MCAST_GROUPS,

	CTRL_ATTR_POLICY,

	CTRL_ATTR_OP_POLICY,

	__CTRL_ATTR_MAX,

};
@@ -85,6 +86,15 @@ enum { 
	__CTRL_ATTR_MCAST_GRP_MAX,

};



enum {

	CTRL_ATTR_POLICY_UNSPEC,

	CTRL_ATTR_POLICY_DO,

	CTRL_ATTR_POLICY_DUMP,



	__CTRL_ATTR_POLICY_DUMP_MAX,

	CTRL_ATTR_POLICY_DUMP_MAX = __CTRL_ATTR_POLICY_DUMP_MAX - 1

};



#define CTRL_ATTR_MCAST_GRP_MAX (__CTRL_ATTR_MCAST_GRP_MAX - 1)

net/netlink/genetlink.c

+92 −10
Original line number Diff line number Diff line
@@ -1112,7 +1112,10 @@ static int genl_ctrl_event(int event, const struct genl_family *family, 


struct ctrl_dump_policy_ctx {

	struct netlink_policy_dump_state *state;

	const struct genl_family *rt;

	unsigned int opidx;

	u16 fam_id;

	u8 policies:1;

};



static const struct nla_policy ctrl_policy_policy[] = {
@@ -1127,6 +1130,8 @@ static int ctrl_dumppolicy_start(struct netlink_callback *cb) 
	struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;

	struct nlattr **tb = info->attrs;

	const struct genl_family *rt;

	struct genl_ops op;

	int err, i;



	BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
@@ -1147,11 +1152,23 @@ static int ctrl_dumppolicy_start(struct netlink_callback *cb) 
	if (!rt)

		return -ENOENT;



	if (!rt->policy)

		return -ENODATA;

	ctx->rt = rt;



	for (i = 0; i < genl_get_cmd_cnt(rt); i++) {

		genl_get_cmd_by_index(i, rt, &op);



		if (op.policy) {

			err = netlink_policy_dump_add_policy(&ctx->state,

							     op.policy,

							     op.maxattr);

			if (err)

				return err;

		}

	}



	return netlink_policy_dump_add_policy(&ctx->state, rt->policy,

					      rt->maxattr);

	if (!ctx->state)

		return -ENODATA;

	return 0;

}



static void *ctrl_dumppolicy_prep(struct sk_buff *skb,
@@ -1172,12 +1189,78 @@ static void *ctrl_dumppolicy_prep(struct sk_buff *skb, 
	return hdr;

}



static int ctrl_dumppolicy_put_op(struct sk_buff *skb,

				  struct netlink_callback *cb,

			          struct genl_ops *op)

{

	struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;

	struct nlattr *nest_pol, *nest_op;

	void *hdr;

	int idx;



	/* skip if we have nothing to show */

	if (!op->policy)

		return 0;

	if (!op->doit &&

	    (!op->dumpit || op->validate & GENL_DONT_VALIDATE_DUMP))

		return 0;



	hdr = ctrl_dumppolicy_prep(skb, cb);

	if (!hdr)

		return -ENOBUFS;



	nest_pol = nla_nest_start(skb, CTRL_ATTR_OP_POLICY);

	if (!nest_pol)

		goto err;



	nest_op = nla_nest_start(skb, op->cmd);

	if (!nest_op)

		goto err;



	/* for now both do/dump are always the same */

	idx = netlink_policy_dump_get_policy_idx(ctx->state,

						 op->policy,

						 op->maxattr);



	if (op->doit && nla_put_u32(skb, CTRL_ATTR_POLICY_DO, idx))

		goto err;



	if (op->dumpit && !(op->validate & GENL_DONT_VALIDATE_DUMP) &&

	    nla_put_u32(skb, CTRL_ATTR_POLICY_DUMP, idx))

		goto err;



	nla_nest_end(skb, nest_op);

	nla_nest_end(skb, nest_pol);

	genlmsg_end(skb, hdr);



	return 0;

err:

	genlmsg_cancel(skb, hdr);

	return -ENOBUFS;

}



static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)

{

	struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;

	void *hdr;



	if (!ctx->policies) {

		while (ctx->opidx < genl_get_cmd_cnt(ctx->rt)) {

			struct genl_ops op;



			genl_get_cmd_by_index(ctx->opidx, ctx->rt, &op);



			if (ctrl_dumppolicy_put_op(skb, cb, &op))

				return skb->len;



			ctx->opidx++;

		}



		/* completed with the per-op policy index list */

		ctx->policies = true;

	}



	while (netlink_policy_dump_loop(ctx->state)) {

		void *hdr;

		struct nlattr *nest;



		hdr = ctrl_dumppolicy_prep(skb, cb);
@@ -1194,13 +1277,12 @@ static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb) 
		nla_nest_end(skb, nest);



		genlmsg_end(skb, hdr);

		continue;

	}



	return skb->len;



nla_put_failure:

	genlmsg_cancel(skb, hdr);

		break;

	}



	return skb->len;

}