Commit e992a6ed authored by Jakub Kicinski's avatar Jakub Kicinski Committed by David S. Miller
Browse files

genetlink: allow dumping command-specific policy 



Right now CTRL_CMD_GETPOLICY can only dump the family-wide
policy. Support dumping policy of a specific op.

v3:
 - rebase after per-op policy export and handle that
v2:
 - make cmd U32, just in case.
v1:
 - don't echo op in the output in a naive way, this should
   make it cleaner to extend the output format for dumping
   policies for all the commands at once in the future.

Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20201001225933.1373426-11-kuba@kernel.org


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 50a896cf

include/uapi/linux/genetlink.h

+1 −0
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ enum { 
	CTRL_ATTR_MCAST_GROUPS,

	CTRL_ATTR_POLICY,

	CTRL_ATTR_OP_POLICY,

	CTRL_ATTR_OP,

	__CTRL_ATTR_MAX,

};

net/netlink/genetlink.c

+36 −5
Original line number Diff line number Diff line
@@ -123,7 +123,7 @@ static void genl_op_from_full(const struct genl_family *family, 
		op->policy = family->policy;

}



static int genl_get_cmd_full(u8 cmd, const struct genl_family *family,

static int genl_get_cmd_full(u32 cmd, const struct genl_family *family,

			     struct genl_ops *op)

{

	int i;
@@ -152,7 +152,7 @@ static void genl_op_from_small(const struct genl_family *family, 
	op->policy = family->policy;

}



static int genl_get_cmd_small(u8 cmd, const struct genl_family *family,

static int genl_get_cmd_small(u32 cmd, const struct genl_family *family,

			      struct genl_ops *op)

{

	int i;
@@ -166,7 +166,7 @@ static int genl_get_cmd_small(u8 cmd, const struct genl_family *family, 
	return -ENOENT;

}



static int genl_get_cmd(u8 cmd, const struct genl_family *family,

static int genl_get_cmd(u32 cmd, const struct genl_family *family,

			struct genl_ops *op)

{

	if (!genl_get_cmd_full(cmd, family, op))
@@ -1114,14 +1114,17 @@ struct ctrl_dump_policy_ctx { 
	struct netlink_policy_dump_state *state;

	const struct genl_family *rt;

	unsigned int opidx;

	u32 op;

	u16 fam_id;

	u8 policies:1;

	u8 policies:1,

	   single_op:1;

};



static const struct nla_policy ctrl_policy_policy[] = {

	[CTRL_ATTR_FAMILY_ID]	= { .type = NLA_U16 },

	[CTRL_ATTR_FAMILY_NAME]	= { .type = NLA_NUL_STRING,

				    .len = GENL_NAMSIZ - 1 },

	[CTRL_ATTR_OP]		= { .type = NLA_U32 },

};



static int ctrl_dumppolicy_start(struct netlink_callback *cb)
@@ -1154,6 +1157,23 @@ static int ctrl_dumppolicy_start(struct netlink_callback *cb) 


	ctx->rt = rt;



	if (tb[CTRL_ATTR_OP]) {

		ctx->single_op = true;

		ctx->op = nla_get_u32(tb[CTRL_ATTR_OP]);



		err = genl_get_cmd(ctx->op, rt, &op);

		if (err) {

			NL_SET_BAD_ATTR(cb->extack, tb[CTRL_ATTR_OP]);

			return err;

		}



		if (!op.policy)

			return -ENODATA;



		return netlink_policy_dump_add_policy(&ctx->state, op.policy,

						      op.maxattr);

	}



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

		genl_get_cmd_by_index(i, rt, &op);
@@ -1248,7 +1268,18 @@ static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb) 
		while (ctx->opidx < genl_get_cmd_cnt(ctx->rt)) {

			struct genl_ops op;



			if (ctx->single_op) {

				int err;



				err = genl_get_cmd(ctx->op, ctx->rt, &op);

				if (WARN_ON(err))

					return skb->len;



				/* break out of the loop after this one */

				ctx->opidx = genl_get_cmd_cnt(ctx->rt);

			} else {

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

			}



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

				return skb->len;

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