From 4c48301594591a92a123b68fa8f9e1c129ce65ae Mon Sep 17 00:00:00 2001 From: Thomas Haller Date: Tue, 2 May 2023 14:41:05 +0200 Subject: device: don't reset "net.ipv6.conf.$IFACE.forwarding" According to systemd, IPv6 forwarding is special anyway, and they only enable forwarding for "net.ipv6.conf.all.forwarding" ([1]). Since commit 46e63e03af58 ('device: announce the managed IPv6 configuration with ipv6.method=shared') we support "ipv6.method=shared" and enable forwarding for IPv6, on the interface. Whether that makes sense is questionable, given [1] and the claim that setting it per-interface is not useful. Anyway, since that change we always reset the "forwarding" sysctl to zero, when we don't enable shared mode. That is not right, because the user didn't explicitly ask for that (and there is no configuration option like systemd-networkd's "IPForward=" setting to control that). What we instead should do, not touch/reset the sysctl, unless we really want to. No longer set "forwarding" to zero by default. And only restore the previous value (_dev_sysctl_save_ip6_properties()) if we actually changed the value to "1". [1] https://github.com/systemd/systemd/blob/b8fba0cded2c3e14fe8c0b52aae3ecf2c9fa718e/src/network/networkd-sysctl.c#L79 https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues/923 Fixes: 46e63e03af58 ('device: announce the managed IPv6 configuration with ipv6.method=shared') https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1616 --- src/core/devices/nm-device.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/src/core/devices/nm-device.c b/src/core/devices/nm-device.c index ed840044c5..6639492ee5 100644 --- a/src/core/devices/nm-device.c +++ b/src/core/devices/nm-device.c @@ -11860,7 +11860,18 @@ _dev_ipac6_start(NMDevice *self) } if (nm_ndisc_get_node_type(priv->ipac6_data.ndisc) == NM_NDISC_NODE_TYPE_ROUTER) { - nm_device_sysctl_ip_conf_set(self, AF_INET6, "forwarding", "1"); + gs_free char *sysctl_value = NULL; + + sysctl_value = nm_device_sysctl_ip_conf_get(self, AF_INET6, "forwarding"); + if (!nm_streq0(sysctl_value, "1")) { + if (sysctl_value) { + g_hash_table_insert(priv->ip6_saved_properties, + "forwarding", + g_steal_pointer(&sysctl_value)); + } + nm_device_sysctl_ip_conf_set(self, AF_INET6, "forwarding", "1"); + } + priv->needs_ip6_subnet = TRUE; g_signal_emit(self, signals[IP6_SUBNET_NEEDED], 0); } @@ -11918,7 +11929,6 @@ _dev_sysctl_save_ip6_properties(NMDevice *self) { static const char *const ip6_properties_to_save[] = { "accept_ra", - "forwarding", "disable_ipv6", "hop_limit", "use_tempaddr", @@ -15838,7 +15848,6 @@ ip6_managed_setup(NMDevice *self) _dev_sysctl_set_disable_ipv6(self, FALSE); nm_device_sysctl_ip_conf_set(self, AF_INET6, "accept_ra", "0"); nm_device_sysctl_ip_conf_set(self, AF_INET6, "use_tempaddr", "0"); - nm_device_sysctl_ip_conf_set(self, AF_INET6, "forwarding", "0"); } static void -- cgit v1.2.1