From: Ido Schimmel <idosch@idosch.org>
To: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>
Cc: netdev@vger.kernel.org, David Miller <davem@davemloft.net>,
David Ahern <dsahern@gmail.com>,
Stephen Hemminger <stephen@networkplumber.org>,
Ido Schimmel <idosch@nvidia.com>,
Jakub Kicinski <kuba@kernel.org>, Roopa Prabhu <roopa@nvidia.com>,
Andrei Vagin <avagin@gmail.com>,
Pavel Tikhomirov <ptikhomirov@virtuozzo.com>,
Alexander Mikhalitsyn <alexander@mihalicyn.com>
Subject: Re: [PATCH net-next] rtnetlink: add RTNH_REJECT_MASK
Date: Sun, 28 Nov 2021 16:01:27 +0200 [thread overview]
Message-ID: <YaOLt2M1hBnoVFKd@shredder> (raw)
In-Reply-To: <20211126134311.920808-2-alexander.mikhalitsyn@virtuozzo.com>
On Fri, Nov 26, 2021 at 04:43:11PM +0300, Alexander Mikhalitsyn wrote:
> diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
> index 5888492a5257..9c065e2fdef9 100644
> --- a/include/uapi/linux/rtnetlink.h
> +++ b/include/uapi/linux/rtnetlink.h
> @@ -417,6 +417,9 @@ struct rtnexthop {
> #define RTNH_COMPARE_MASK (RTNH_F_DEAD | RTNH_F_LINKDOWN | \
> RTNH_F_OFFLOAD | RTNH_F_TRAP)
>
> +/* these flags can't be set by the userspace */
> +#define RTNH_REJECT_MASK (RTNH_F_DEAD | RTNH_F_LINKDOWN)
> +
> /* Macros to handle hexthops */
>
> #define RTNH_ALIGNTO 4
> diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
> index 4c0c33e4710d..805f5e05b56d 100644
> --- a/net/ipv4/fib_semantics.c
> +++ b/net/ipv4/fib_semantics.c
> @@ -685,7 +685,7 @@ static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
> return -EINVAL;
> }
>
> - if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
> + if (rtnh->rtnh_flags & RTNH_REJECT_MASK) {
> NL_SET_ERR_MSG(extack,
> "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
> return -EINVAL;
> @@ -1363,7 +1363,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
> goto err_inval;
> }
>
> - if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
> + if (cfg->fc_flags & RTNH_REJECT_MASK) {
> NL_SET_ERR_MSG(extack,
> "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
Instead of a deny list as in the legacy nexthop code, the new nexthop
code has an allow list (from rtm_to_nh_config()):
```
if (nhm->nh_flags & ~NEXTHOP_VALID_USER_FLAGS) {
NL_SET_ERR_MSG(extack, "Invalid nexthop flags in ancillary header");
goto out;
}
```
Where:
```
#define NEXTHOP_VALID_USER_FLAGS RTNH_F_ONLINK
```
So while the legacy nexthop code allows setting flags such as
RTNH_F_OFFLOAD, the new nexthop code denies them. I don't have a use
case for setting these flags from user space so I don't care if we allow
or deny them, but I believe the legacy and new nexthop code should be
consistent.
WDYT? Should we allow these flags in the new nexthop code as well or
keep denying them?
> goto err_inval;
> --
> 2.31.1
>
next prev parent reply other threads:[~2021-11-28 14:03 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-11 16:02 [RFC PATCH iproute2] ip route: save: exclude rtnh_flags which can't be set Alexander Mikhalitsyn
2021-11-11 16:02 ` [RFC PATCH net-next] rtnetlink: add RTNH_F_REJECT_MASK Alexander Mikhalitsyn
2021-11-11 17:48 ` Jakub Kicinski
2021-11-11 17:51 ` Alexander Mikhalitsyn
2021-11-11 17:56 ` Jakub Kicinski
2021-11-11 18:01 ` Alexander Mikhalitsyn
2021-11-11 19:13 ` David Ahern
2021-11-11 19:23 ` Alexander Mikhalitsyn
2021-11-11 22:19 ` David Ahern
2021-11-12 1:02 ` Roopa Prabhu
2021-11-12 2:27 ` David Ahern
2021-11-26 13:43 ` [PATCH iproute2] ip route: save: exclude rtnh_flags which can't be set Alexander Mikhalitsyn
2021-11-26 13:43 ` [PATCH net-next] rtnetlink: add RTNH_REJECT_MASK Alexander Mikhalitsyn
2021-11-28 14:01 ` Ido Schimmel [this message]
2021-11-29 0:19 ` David Ahern
2021-11-30 7:59 ` Ido Schimmel
2021-11-30 8:35 ` Alexander Mikhalitsyn
2021-11-30 9:28 ` Ido Schimmel
2021-11-30 9:53 ` Alexander Mikhalitsyn
2021-11-30 10:28 ` Ido Schimmel
2021-11-30 15:12 ` David Ahern
2021-11-30 8:18 ` Alexander Mikhalitsyn
2021-11-28 13:09 ` [PATCH iproute2] ip route: save: exclude rtnh_flags which can't be set Ido Schimmel
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