diff options
| author | Gabriel Goller <g.goller@proxmox.com> | 2025-07-22 11:18:45 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-07-25 23:06:19 +0300 |
| commit | f24987ef6959a7efaf79bffd265522c3df18d431 (patch) | |
| tree | 69e5a8eb353caac1921f8a64fec640e7087f785d /include/uapi/linux | |
| parent | 9312ee76490df61491fee19b5ce71f71b6de908c (diff) | |
| download | linux-f24987ef6959a7efaf79bffd265522c3df18d431.tar.xz | |
ipv6: add `force_forwarding` sysctl to enable per-interface forwarding
It is currently impossible to enable ipv6 forwarding on a per-interface
basis like in ipv4. To enable forwarding on an ipv6 interface we need to
enable it on all interfaces and disable it on the other interfaces using
a netfilter rule. This is especially cumbersome if you have lots of
interfaces and only want to enable forwarding on a few. According to the
sysctl docs [0] the `net.ipv6.conf.all.forwarding` enables forwarding
for all interfaces, while the interface-specific
`net.ipv6.conf.<interface>.forwarding` configures the interface
Host/Router configuration.
Introduce a new sysctl flag `force_forwarding`, which can be set on every
interface. The ip6_forwarding function will then check if the global
forwarding flag OR the force_forwarding flag is active and forward the
packet.
To preserve backwards-compatibility reset the flag (on all interfaces)
to 0 if the net.ipv6.conf.all.forwarding flag is set to 0.
Add a short selftest that checks if a packet gets forwarded with and
without `force_forwarding`.
[0]: https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
Link: https://patch.msgid.link/20250722081847.132632-1-g.goller@proxmox.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include/uapi/linux')
| -rw-r--r-- | include/uapi/linux/ipv6.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/netconf.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/sysctl.h | 1 |
3 files changed, 3 insertions, 0 deletions
diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h index cf592d7b630f..d4d3ae774b26 100644 --- a/include/uapi/linux/ipv6.h +++ b/include/uapi/linux/ipv6.h @@ -199,6 +199,7 @@ enum { DEVCONF_NDISC_EVICT_NOCARRIER, DEVCONF_ACCEPT_UNTRACKED_NA, DEVCONF_ACCEPT_RA_MIN_LFT, + DEVCONF_FORCE_FORWARDING, DEVCONF_MAX }; diff --git a/include/uapi/linux/netconf.h b/include/uapi/linux/netconf.h index fac4edd55379..1c8c84d65ae3 100644 --- a/include/uapi/linux/netconf.h +++ b/include/uapi/linux/netconf.h @@ -19,6 +19,7 @@ enum { NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN, NETCONFA_INPUT, NETCONFA_BC_FORWARDING, + NETCONFA_FORCE_FORWARDING, __NETCONFA_MAX }; #define NETCONFA_MAX (__NETCONFA_MAX - 1) diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h index 8981f00204db..63d1464cb71c 100644 --- a/include/uapi/linux/sysctl.h +++ b/include/uapi/linux/sysctl.h @@ -573,6 +573,7 @@ enum { NET_IPV6_ACCEPT_RA_FROM_LOCAL=26, NET_IPV6_ACCEPT_RA_RT_INFO_MIN_PLEN=27, NET_IPV6_RA_DEFRTR_METRIC=28, + NET_IPV6_FORCE_FORWARDING=29, __NET_IPV6_MAX }; |