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authorJakub Kicinski <kuba@kernel.org>2023-06-09 14:53:30 -0700
committerDavid S. Miller <davem@davemloft.net>2023-06-12 11:32:44 +0100
commit5ab8c41cef30d8b6160a80b69d2eb39d570491ac (patch)
tree3dda5eab24d6af40aa6fca32628be0b316017aa6
parent238131684f7b1bc2e0788583f22ed67bf3f5ca37 (diff)
netlink: support extack in dump ->start()
Commit 4a19edb60d02 ("netlink: Pass extack to dump handlers") added extack support to netlink dumps. It was focused on rtnl and since rtnl does not use ->start(), ->done() callbacks it ignored those. Genetlink on the other hand uses ->start() extensively, for parsing and input validation. Pass the extact in via struct netlink_dump_control and link it to cb for the time of ->start(). Both struct netlink_dump_control and extack itself live on the stack so we can't keep the same extack for the duration of the dump. This means that the extack visible in ->start() and each ->dump() callbacks will be different. Corner cases like reporting a warning message in DONE across dump calls are still not supported. We could put the extack (for dumps) in the socket struct, but layering makes it slightly awkward (extack pointer is decided before the DO / DUMP split). The genetlink dump error extacks are now surfaced: $ cli.py --spec netlink/specs/ethtool.yaml --dump channels-get lib.ynl.NlError: Netlink error: Invalid argument nl_len = 64 (48) nl_flags = 0x300 nl_type = 2 error: -22 extack: {'msg': 'request header missing'} Previously extack was missing: $ cli.py --spec netlink/specs/ethtool.yaml --dump channels-get lib.ynl.NlError: Netlink error: Invalid argument nl_len = 36 (20) nl_flags = 0x100 nl_type = 2 error: -22 Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/netlink.h1
-rw-r--r--net/netlink/af_netlink.c2
-rw-r--r--net/netlink/genetlink.c2
3 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 19c0791ed9d5..9eec3f4f5351 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -311,6 +311,7 @@ struct netlink_dump_control {
int (*start)(struct netlink_callback *);
int (*dump)(struct sk_buff *skb, struct netlink_callback *);
int (*done)(struct netlink_callback *);
+ struct netlink_ext_ack *extack;
void *data;
struct module *module;
u32 min_dump_alloc;
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 3a1e0fd5bf14..cbd9aa7ee24a 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2360,7 +2360,9 @@ int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
cb->strict_check = !!(nlk2->flags & NETLINK_F_STRICT_CHK);
if (control->start) {
+ cb->extack = control->extack;
ret = control->start(cb);
+ cb->extack = NULL;
if (ret)
goto error_put;
}
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 04c4036bf406..a157247a1e45 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -912,6 +912,7 @@ static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
.start = genl_start,
.dump = genl_lock_dumpit,
.done = genl_lock_done,
+ .extack = extack,
};
genl_unlock();
@@ -924,6 +925,7 @@ static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
.start = genl_start,
.dump = ops->dumpit,
.done = genl_parallel_done,
+ .extack = extack,
};
err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);