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Message-Id: <20201003104138.7f59292a5c88.I19674e30193a115c120d976d1e3ebc9ec7c8235e@changeid>
Date: Sat, 3 Oct 2020 10:44:45 +0200
From: Johannes Berg <johannes@...solutions.net>
To: netdev@...r.kernel.org
Cc: Jakub Kicinski <kuba@...nel.org>, David Ahern <dsahern@...il.com>,
Johannes Berg <johannes.berg@...el.com>
Subject: [PATCH v3 4/5] genetlink: properly support per-op policy dumping
From: Johannes Berg <johannes.berg@...el.com>
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@...el.com>
---
include/uapi/linux/genetlink.h | 10 ++++
net/netlink/genetlink.c | 102 +++++++++++++++++++++++++++++----
2 files changed, 102 insertions(+), 10 deletions(-)
diff --git a/include/uapi/linux/genetlink.h b/include/uapi/linux/genetlink.h
index 9c0636ec2286..bc9c98e84828 100644
--- a/include/uapi/linux/genetlink.h
+++ b/include/uapi/linux/genetlink.h
@@ -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)
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 5e33c7938470..eb916c44884f 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -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);
@@ -1194,14 +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)
--
2.26.2
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