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Date: Fri, 2 Oct 2020 11:09:44 +0200
From: Johannes Berg <johannes@...solutions.net>
To: netdev@...r.kernel.org
Cc: Jakub Kicinski <kuba@...nel.org>,
Johannes Berg <johannes.berg@...el.com>
Subject: [PATCH 5/5] 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
containing the cmd -> policy index mapping.
When a single op is requested, the CTRL_ATTR_OP_POLICY will be
added but the policy for this op is still guaranteed to be at
index 0, so that's just for convenience.
Signed-off-by: Johannes Berg <johannes.berg@...el.com>
---
include/uapi/linux/genetlink.h | 1 +
net/netlink/genetlink.c | 107 ++++++++++++++++++++++++++++-----
2 files changed, 93 insertions(+), 15 deletions(-)
diff --git a/include/uapi/linux/genetlink.h b/include/uapi/linux/genetlink.h
index 7dbe2d5d7d46..583dcc737250 100644
--- a/include/uapi/linux/genetlink.h
+++ b/include/uapi/linux/genetlink.h
@@ -65,6 +65,7 @@ enum {
CTRL_ATTR_MCAST_GROUPS,
CTRL_ATTR_POLICY,
CTRL_ATTR_OP,
+ CTRL_ATTR_OP_POLICY,
__CTRL_ATTR_MAX,
};
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 0ab9549e30ee..b2a87fbd3875 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -1112,7 +1112,12 @@ 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;
+ u32 op;
u16 fam_id;
+ u8 policies:1,
+ single_op:1;
};
static const struct nla_policy ctrl_policy_policy[] = {
@@ -1129,7 +1134,7 @@ static int ctrl_dumppolicy_start(struct netlink_callback *cb)
struct nlattr **tb = info->attrs;
const struct genl_family *rt;
struct genl_ops op;
- int err;
+ int err, i;
BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
@@ -1150,22 +1155,40 @@ static int ctrl_dumppolicy_start(struct netlink_callback *cb)
if (!rt)
return -ENOENT;
+ ctx->rt = rt;
+
if (tb[CTRL_ATTR_OP]) {
- err = genl_get_cmd(nla_get_u32(tb[CTRL_ATTR_OP]), rt, &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;
}
- } else {
- op.policy = rt->policy;
- op.maxattr = rt->maxattr;
+
+ if (!op.policy)
+ return -ENODATA;
+
+ return netlink_policy_dump_add_policy(&ctx->state, op.policy,
+ op.maxattr);
}
- if (!op.policy)
- return -ENODATA;
+ 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, op.policy,
- op.maxattr);
+ if (!ctx->state)
+ return -ENODATA;
+ return 0;
}
static void *ctrl_dumppolicy_prep(struct sk_buff *skb,
@@ -1189,11 +1212,65 @@ static void *ctrl_dumppolicy_prep(struct sk_buff *skb,
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) {
+ if (ctx->single_op) {
+ struct nlattr *nest;
+
+ hdr = ctrl_dumppolicy_prep(skb, cb);
+ if (!hdr)
+ goto nla_put_failure;
+
+ nest = nla_nest_start(skb, CTRL_ATTR_OP_POLICY);
+ if (!nest)
+ goto nla_put_failure;
+
+ if (nla_put_u32(skb, ctx->op, 0))
+ goto nla_put_failure;
+
+ nla_nest_end(skb, nest);
+ genlmsg_end(skb, hdr);
+
+ /* skip loop below */
+ ctx->opidx = genl_get_cmd_cnt(ctx->rt);
+ }
+
+ while (ctx->opidx < genl_get_cmd_cnt(ctx->rt)) {
+ struct genl_ops op;
+ struct nlattr *nest;
+ int idx;
+
+ hdr = ctrl_dumppolicy_prep(skb, cb);
+ if (!hdr)
+ goto nla_put_failure;
+
+ genl_get_cmd_by_index(ctx->opidx, ctx->rt, &op);
+
+ nest = nla_nest_start(skb, CTRL_ATTR_OP_POLICY);
+ if (!nest)
+ goto nla_put_failure;
+
+ idx = netlink_policy_dump_get_policy_idx(ctx->state,
+ op.policy,
+ op.maxattr);
+ if (nla_put_u32(skb, op.cmd, idx))
+ goto nla_put_failure;
+
+ ctx->opidx++;
+
+ nla_nest_end(skb, nest);
+ genlmsg_end(skb, hdr);
+ }
+
+ /* completed with the per-op policy index list */
+ ctx->policies = true;
+ }
while (netlink_policy_dump_loop(ctx->state)) {
- void *hdr = ctrl_dumppolicy_prep(skb, cb);
struct nlattr *nest;
+ hdr = ctrl_dumppolicy_prep(skb, cb);
if (!hdr)
goto nla_put_failure;
@@ -1201,20 +1278,20 @@ static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
if (!nest)
goto nla_put_failure;
+
if (netlink_policy_dump_write(skb, ctx->state))
goto nla_put_failure;
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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