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genetlink: properly support per-op policy dumping

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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: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Johannes Berg 2020-10-03 10:44:45 +02:00 committed by David S. Miller
parent aa85ee5f95
commit 50a896cf2d
2 changed files with 102 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
include/uapi/linux/genetlink.h
View File

@ -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)

102
net/netlink/genetlink.c
View File

@ -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;
return netlink_policy_dump_add_policy(&ctx->state, rt->policy,
rt->maxattr);
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;
}
}
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);
@ -1194,14 +1277,13 @@ static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
nla_nest_end(skb, nest);
genlmsg_end(skb, hdr);
continue;
nla_put_failure:
genlmsg_cancel(skb, hdr);
break;
}
return skb->len;
nla_put_failure:
genlmsg_cancel(skb, hdr);
return skb->len;
}
static int ctrl_dumppolicy_done(struct netlink_callback *cb)