Commit adc84845 authored by Jakub Kicinski's avatar Jakub Kicinski Committed by David S. Miller
Browse files

genetlink: add a structure for dump state 



Whenever netlink dump uses more than 2 cb->args[] entries
code gets hard to read. We're about to add more state to
ctrl_dumppolicy() so create a structure.

Since the structure is typed and clearly named we can remove
the local fam_id variable and use ctx->fam_id directly.

v3:
 - rebase onto explicit free fix
v1:
 - s/nl_policy_dump/netlink_policy_dump_state/
 - forward declare struct netlink_policy_dump_state,
   and move from passing unsigned long to actual pointer type
 - add build bug on
 - u16 fam_id
 - s/args/ctx/

Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Reviewed-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 66a9b928

include/net/netlink.h

+7 −4
Original line number Diff line number Diff line
@@ -1935,11 +1935,14 @@ void nla_get_range_unsigned(const struct nla_policy *pt, 
void nla_get_range_signed(const struct nla_policy *pt,

			  struct netlink_range_validation_signed *range);



struct netlink_policy_dump_state;



int netlink_policy_dump_start(const struct nla_policy *policy,

			      unsigned int maxtype,

			      unsigned long *state);

bool netlink_policy_dump_loop(unsigned long state);

int netlink_policy_dump_write(struct sk_buff *skb, unsigned long state);

void netlink_policy_dump_free(unsigned long state);

			      struct netlink_policy_dump_state **state);

bool netlink_policy_dump_loop(struct netlink_policy_dump_state *state);

int netlink_policy_dump_write(struct sk_buff *skb,

			      struct netlink_policy_dump_state *state);

void netlink_policy_dump_free(struct netlink_policy_dump_state *state);



#endif

net/netlink/genetlink.c

+18 −10
Original line number Diff line number Diff line
@@ -1102,13 +1102,20 @@ static int genl_ctrl_event(int event, const struct genl_family *family, 
	return 0;

}



struct ctrl_dump_policy_ctx {

	struct netlink_policy_dump_state *state;

	u16 fam_id;

};



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

{

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

	const struct genl_family *rt;

	unsigned int fam_id = cb->args[0];

	int err;



	if (!fam_id) {

	BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));



	if (!ctx->fam_id) {

		struct nlattr *tb[CTRL_ATTR_MAX + 1];



		err = genlmsg_parse(cb->nlh, &genl_ctrl, tb,
@@ -1121,28 +1128,28 @@ static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb) 
			return -EINVAL;



		if (tb[CTRL_ATTR_FAMILY_ID]) {

			fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]);

			ctx->fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]);

		} else {

			rt = genl_family_find_byname(

				nla_data(tb[CTRL_ATTR_FAMILY_NAME]));

			if (!rt)

				return -ENOENT;

			fam_id = rt->id;

			ctx->fam_id = rt->id;

		}

	}



	rt = genl_family_find_byid(fam_id);

	rt = genl_family_find_byid(ctx->fam_id);

	if (!rt)

		return -ENOENT;



	if (!rt->policy)

		return -ENODATA;



	err = netlink_policy_dump_start(rt->policy, rt->maxattr, &cb->args[1]);

	err = netlink_policy_dump_start(rt->policy, rt->maxattr, &ctx->state);

	if (err)

		return err;



	while (netlink_policy_dump_loop(cb->args[1])) {

	while (netlink_policy_dump_loop(ctx->state)) {

		void *hdr;

		struct nlattr *nest;
@@ -1159,7 +1166,7 @@ static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb) 
		if (!nest)

			goto nla_put_failure;



		if (netlink_policy_dump_write(skb, cb->args[1]))

		if (netlink_policy_dump_write(skb, ctx->state))

			goto nla_put_failure;



		nla_nest_end(skb, nest);
@@ -1172,13 +1179,14 @@ static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb) 
		break;

	}



	cb->args[0] = fam_id;

	return skb->len;

}



static int ctrl_dumppolicy_done(struct netlink_callback *cb)

{

	netlink_policy_dump_free(cb->args[1]);

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



	netlink_policy_dump_free(ctx->state);

	return 0;

}

net/netlink/policy.c

+14 −17
Original line number Diff line number Diff line
@@ -14,7 +14,7 @@ 


#define INITIAL_POLICIES_ALLOC	10



struct nl_policy_dump {

struct netlink_policy_dump_state {

	unsigned int policy_idx;

	unsigned int attr_idx;

	unsigned int n_alloc;
@@ -24,11 +24,11 @@ struct nl_policy_dump { 
	} policies[];

};



static int add_policy(struct nl_policy_dump **statep,

static int add_policy(struct netlink_policy_dump_state **statep,

		      const struct nla_policy *policy,

		      unsigned int maxtype)

{

	struct nl_policy_dump *state = *statep;

	struct netlink_policy_dump_state *state = *statep;

	unsigned int n_alloc, i;



	if (!policy || !maxtype)
@@ -62,7 +62,7 @@ static int add_policy(struct nl_policy_dump **statep, 
	return 0;

}



static unsigned int get_policy_idx(struct nl_policy_dump *state,

static unsigned int get_policy_idx(struct netlink_policy_dump_state *state,

				   const struct nla_policy *policy)

{

	unsigned int i;
@@ -78,13 +78,13 @@ static unsigned int get_policy_idx(struct nl_policy_dump *state, 


int netlink_policy_dump_start(const struct nla_policy *policy,

			      unsigned int maxtype,

                              unsigned long *_state)

			      struct netlink_policy_dump_state **statep)

{

	struct nl_policy_dump *state;

	struct netlink_policy_dump_state *state;

	unsigned int policy_idx;

	int err;



	if (*_state)

	if (*statep)

		return 0;



	/*
@@ -128,27 +128,26 @@ int netlink_policy_dump_start(const struct nla_policy *policy, 
		}

	}



	*_state = (unsigned long)state;

	*statep = state;



	return 0;

}



static bool netlink_policy_dump_finished(struct nl_policy_dump *state)

static bool

netlink_policy_dump_finished(struct netlink_policy_dump_state *state)

{

	return state->policy_idx >= state->n_alloc ||

	       !state->policies[state->policy_idx].policy;

}



bool netlink_policy_dump_loop(unsigned long _state)

bool netlink_policy_dump_loop(struct netlink_policy_dump_state *state)

{

	struct nl_policy_dump *state = (void *)_state;



	return !netlink_policy_dump_finished(state);

}



int netlink_policy_dump_write(struct sk_buff *skb, unsigned long _state)

int netlink_policy_dump_write(struct sk_buff *skb,

			      struct netlink_policy_dump_state *state)

{

	struct nl_policy_dump *state = (void *)_state;

	const struct nla_policy *pt;

	struct nlattr *policy, *attr;

	enum netlink_attribute_type type;
@@ -306,9 +305,7 @@ int netlink_policy_dump_write(struct sk_buff *skb, unsigned long _state) 
	return -ENOBUFS;

}



void netlink_policy_dump_free(unsigned long _state)

void netlink_policy_dump_free(struct netlink_policy_dump_state *state)

{

	struct nl_policy_dump *state = (void *)_state;



	kfree(state);

}