From f40d9b20864ae571c31f57989fd869958ce675c2 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 30 Aug 2019 03:53:24 +0300 Subject: [PATCH 1/2] net: bridge: Populate the pvid flag in br_vlan_get_info Currently this simplified code snippet fails: br_vlan_get_pvid(netdev, &pvid); br_vlan_get_info(netdev, pvid, &vinfo); ASSERT(!(vinfo.flags & BRIDGE_VLAN_INFO_PVID)); It is intuitive that the pvid of a netdevice should have the BRIDGE_VLAN_INFO_PVID flag set. However I can't seem to pinpoint a commit where this behavior was introduced. It seems like it's been like that since forever. At a first glance it would make more sense to just handle the BRIDGE_VLAN_INFO_PVID flag in __vlan_add_flags. However, as Nikolay explains: There are a few reasons why we don't do it, most importantly because we need to have only one visible pvid at any single time, even if it's stale - it must be just one. Right now that rule will not be violated by this change, but people will try using this flag and could see two pvids simultaneously. You can see that the pvid code is even using memory barriers to propagate the new value faster and everywhere the pvid is read only once. That is the reason the flag is set dynamically when dumping entries, too. A second (weaker) argument against would be given the above we don't want another way to do the same thing, specifically if it can provide us with two pvids (e.g. if walking the vlan list) or if it can provide us with a pvid different from the one set in the vg. [Obviously, I'm talking about RCU pvid/vlan use cases similar to the dumps. The locked cases are fine. I would like to avoid explaining why this shouldn't be relied upon without locking] So instead of introducing the above change and making sure of the pvid uniqueness under RCU, simply dynamically populate the pvid flag in br_vlan_get_info(). Signed-off-by: Vladimir Oltean Acked-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- net/bridge/br_vlan.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c index f5b2aeebbfe98..bb98984cd27d0 100644 --- a/net/bridge/br_vlan.c +++ b/net/bridge/br_vlan.c @@ -1281,6 +1281,8 @@ int br_vlan_get_info(const struct net_device *dev, u16 vid, p_vinfo->vid = vid; p_vinfo->flags = v->flags; + if (vid == br_get_pvid(vg)) + p_vinfo->flags |= BRIDGE_VLAN_INFO_PVID; return 0; } EXPORT_SYMBOL_GPL(br_vlan_get_info); From 5f33183b7fdfeba98d02b099c9de887378d47943 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 30 Aug 2019 03:53:25 +0300 Subject: [PATCH 2/2] net: dsa: tag_8021q: Restore bridge VLANs when enabling vlan_filtering The bridge core assumes that enabling/disabling vlan_filtering will translate into the simple toggling of a flag for switchdev drivers. That is clearly not the case for sja1105, which alters the VLAN table and the pvids in order to obtain port separation in standalone mode. There are 2 parts to the issue. First, tag_8021q changes the pvid to a unique per-port rx_vid for frame identification. But we need to disable tag_8021q when vlan_filtering kicks in, and at that point, the VLAN configured as pvid will have to be removed from the filtering table of the ports. With an invalid pvid, the ports will drop all traffic. Since the bridge will not call any vlan operation through switchdev after enabling vlan_filtering, we need to ensure we're in a functional state ourselves. Hence read the pvid that the bridge is aware of, and program that into our ports. Secondly, tag_8021q uses the 1024-3071 range privately in vlan_filtering=0 mode. Had the user installed one of these VLANs during a previous vlan_filtering=1 session, then upon the next tag_8021q cleanup for vlan_filtering to kick in again, VLANs in that range will get deleted unconditionally, hence breaking user expectation. So when deleting the VLANs, check if the bridge had knowledge about them, and if it did, re-apply the settings. Wrap this logic inside a dsa_8021q_vid_apply helper function to reduce code duplication. Signed-off-by: Vladimir Oltean Reviewed-by: Vivien Didelot Signed-off-by: David S. Miller --- net/dsa/tag_8021q.c | 102 +++++++++++++++++++++++++++++++++++--------- 1 file changed, 82 insertions(+), 20 deletions(-) diff --git a/net/dsa/tag_8021q.c b/net/dsa/tag_8021q.c index 6ebbd799c4eb6..e44e6275b0a1d 100644 --- a/net/dsa/tag_8021q.c +++ b/net/dsa/tag_8021q.c @@ -91,6 +91,79 @@ int dsa_8021q_rx_source_port(u16 vid) } EXPORT_SYMBOL_GPL(dsa_8021q_rx_source_port); +static int dsa_8021q_restore_pvid(struct dsa_switch *ds, int port) +{ + struct bridge_vlan_info vinfo; + struct net_device *slave; + u16 pvid; + int err; + + if (!dsa_is_user_port(ds, port)) + return 0; + + slave = ds->ports[port].slave; + + err = br_vlan_get_pvid(slave, &pvid); + if (err < 0) + /* There is no pvid on the bridge for this port, which is + * perfectly valid. Nothing to restore, bye-bye! + */ + return 0; + + err = br_vlan_get_info(slave, pvid, &vinfo); + if (err < 0) { + dev_err(ds->dev, "Couldn't determine PVID attributes\n"); + return err; + } + + return dsa_port_vid_add(&ds->ports[port], pvid, vinfo.flags); +} + +/* If @enabled is true, installs @vid with @flags into the switch port's HW + * filter. + * If @enabled is false, deletes @vid (ignores @flags) from the port. Had the + * user explicitly configured this @vid through the bridge core, then the @vid + * is installed again, but this time with the flags from the bridge layer. + */ +static int dsa_8021q_vid_apply(struct dsa_switch *ds, int port, u16 vid, + u16 flags, bool enabled) +{ + struct dsa_port *dp = &ds->ports[port]; + struct bridge_vlan_info vinfo; + int err; + + if (enabled) + return dsa_port_vid_add(dp, vid, flags); + + err = dsa_port_vid_del(dp, vid); + if (err < 0) + return err; + + /* Nothing to restore from the bridge for a non-user port. + * The CPU port VLANs are restored implicitly with the user ports, + * similar to how the bridge does in dsa_slave_vlan_add and + * dsa_slave_vlan_del. + */ + if (!dsa_is_user_port(ds, port)) + return 0; + + err = br_vlan_get_info(dp->slave, vid, &vinfo); + /* Couldn't determine bridge attributes for this vid, + * it means the bridge had not configured it. + */ + if (err < 0) + return 0; + + /* Restore the VID from the bridge */ + err = dsa_port_vid_add(dp, vid, vinfo.flags); + if (err < 0) + return err; + + vinfo.flags &= ~BRIDGE_VLAN_INFO_PVID; + + return dsa_port_vid_add(dp->cpu_dp, vid, vinfo.flags); +} + /* RX VLAN tagging (left) and TX VLAN tagging (right) setup shown for a single * front-panel switch port (here swp0). * @@ -146,8 +219,6 @@ EXPORT_SYMBOL_GPL(dsa_8021q_rx_source_port); int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int port, bool enabled) { int upstream = dsa_upstream_port(ds, port); - struct dsa_port *dp = &ds->ports[port]; - struct dsa_port *upstream_dp = &ds->ports[upstream]; u16 rx_vid = dsa_8021q_rx_vid(ds, port); u16 tx_vid = dsa_8021q_tx_vid(ds, port); int i, err; @@ -164,7 +235,6 @@ int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int port, bool enabled) * restrictions, so there are no concerns about leaking traffic. */ for (i = 0; i < ds->num_ports; i++) { - struct dsa_port *other_dp = &ds->ports[i]; u16 flags; if (i == upstream) @@ -177,10 +247,7 @@ int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int port, bool enabled) /* The RX VID is a regular VLAN on all others */ flags = BRIDGE_VLAN_INFO_UNTAGGED; - if (enabled) - err = dsa_port_vid_add(other_dp, rx_vid, flags); - else - err = dsa_port_vid_del(other_dp, rx_vid); + err = dsa_8021q_vid_apply(ds, i, rx_vid, flags, enabled); if (err) { dev_err(ds->dev, "Failed to apply RX VID %d to port %d: %d\n", rx_vid, port, err); @@ -191,10 +258,7 @@ int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int port, bool enabled) /* CPU port needs to see this port's RX VID * as tagged egress. */ - if (enabled) - err = dsa_port_vid_add(upstream_dp, rx_vid, 0); - else - err = dsa_port_vid_del(upstream_dp, rx_vid); + err = dsa_8021q_vid_apply(ds, upstream, rx_vid, 0, enabled); if (err) { dev_err(ds->dev, "Failed to apply RX VID %d to port %d: %d\n", rx_vid, port, err); @@ -202,26 +266,24 @@ int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int port, bool enabled) } /* Finally apply the TX VID on this port and on the CPU port */ - if (enabled) - err = dsa_port_vid_add(dp, tx_vid, BRIDGE_VLAN_INFO_UNTAGGED); - else - err = dsa_port_vid_del(dp, tx_vid); + err = dsa_8021q_vid_apply(ds, port, tx_vid, BRIDGE_VLAN_INFO_UNTAGGED, + enabled); if (err) { dev_err(ds->dev, "Failed to apply TX VID %d on port %d: %d\n", tx_vid, port, err); return err; } - if (enabled) - err = dsa_port_vid_add(upstream_dp, tx_vid, 0); - else - err = dsa_port_vid_del(upstream_dp, tx_vid); + err = dsa_8021q_vid_apply(ds, upstream, tx_vid, 0, enabled); if (err) { dev_err(ds->dev, "Failed to apply TX VID %d on port %d: %d\n", tx_vid, upstream, err); return err; } - return 0; + if (!enabled) + err = dsa_8021q_restore_pvid(ds, port); + + return err; } EXPORT_SYMBOL_GPL(dsa_port_setup_8021q_tagging);