kernel/include/linux/dsa/8021q.h, branch linux-5.11.y

net: dsa: tag_8021q: add VLANs to the master interface too

2020-09-21T02:01:34Z

The whole purpose of tag_8021q is to send VLAN-tagged traffic to the CPU, from which the driver can decode the source port and switch id. Currently this only works if the VLAN filtering on the master is disabled. Change that by explicitly adding code to tag_8021q.c to add the VLANs corresponding to the tags to the filter of the master interface. Because we now need to call vlan_vid_add, then we also need to hold the RTNL mutex. Propagate that requirement to the callers of dsa_8021q_setup and modify the existing call sites as appropriate. Note that one call path, sja1105_best_effort_vlan_filtering_set -> sja1105_vlan_filtering -> sja1105_setup_8021q_tagging, was already holding this lock. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller

net: dsa: tag_8021q: add a context structure

2020-09-12T00:30:43Z

While working on another tag_8021q driver implementation, some things became apparent: - It is not mandatory for a DSA driver to offload the tag_8021q VLANs by using the VLAN table per se. For example, it can add custom TCAM rules that simply encapsulate RX traffic, and redirect & decapsulate rules for TX traffic. For such a driver, it makes no sense to receive the tag_8021q configuration through the same callback as it receives the VLAN configuration from the bridge and the 8021q modules. - Currently, sja1105 (the only tag_8021q user) sets a priv->expect_dsa_8021q variable to distinguish between the bridge calling, and tag_8021q calling. That can be improved, to say the least. - The crosschip bridging operations are, in fact, stateful already. The list of crosschip_links must be kept by the caller and passed to the relevant tag_8021q functions. So it would be nice if the tag_8021q configuration was more self-contained. This patch attempts to do that. Create a struct dsa_8021q_context which encapsulates a struct dsa_switch, and has 2 function pointers for adding and deleting a VLAN. These will replace the previous channel to the driver, which was through the .port_vlan_add and .port_vlan_del callbacks of dsa_switch_ops. Also put the list of crosschip_links into this dsa_8021q_context. Drivers that don't support cross-chip bridging can simply omit to initialize this list, as long as they dont call any cross-chip function. The sja1105_vlan_add and sja1105_vlan_del functions are refactored into a smaller sja1105_vlan_add_one, which now has 2 entry points: - sja1105_vlan_add, from struct dsa_switch_ops - sja1105_dsa_8021q_vlan_add, from the tag_8021q ops But even this change is fairly trivial. It just reflects the fact that for sja1105, the VLANs from these 2 channels end up in the same hardware table. However that is not necessarily true in the general sense (and that's the reason for making this change). The rest of the patch is mostly plain refactoring of "ds" -> "ctx". The dsa_8021q_context structure needs to be propagated because adding a VLAN is now done through the ops function pointers inside of it. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller

net: dsa: tag_8021q: setup tagging via a single function call

2020-09-12T00:30:43Z

There is no point in calling dsa_port_setup_8021q_tagging for each individual port. Additionally, it will become more difficult to do that when we'll have a context structure to tag_8021q (next patch). So refactor this now. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller

net: dsa: tag_8021q: include missing refcount.h

2020-09-12T00:30:43Z

The previous assumption was that the caller would already have this header file included. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller

net: dsa: tag_8021q: support up to 8 VLANs per port using sub-VLANs

2020-05-12T20:08:08Z

For switches that support VLAN retagging, such as sja1105, we extend dsa_8021q by encoding a "sub-VLAN" into the remaining 3 free bits in the dsa_8021q tag. A sub-VLAN is nothing more than a number in the range 0-7, which serves as an index into a per-port driver lookup table. The sub-VLAN value of zero means that traffic is untagged (this is also backwards-compatible with dsa_8021q without retagging). The switch should be configured to retag VLAN-tagged traffic that gets transmitted towards the CPU port (and towards the CPU only). Example: bridge vlan add dev sw1p0 vid 100 The switch retags frames received on port 0, going to the CPU, and having VID 100, to the VID of 1104 (0x0450). In dsa_8021q language: | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | +-----------+-----+-----------------+-----------+-----------------------+ | DIR | SVL | SWITCH_ID | SUBVLAN | PORT | +-----------+-----+-----------------+-----------+-----------------------+ 0x0450 means: - DIR = 0b01: this is an RX VLAN - SUBVLAN = 0b001: this is subvlan #1 - SWITCH_ID = 0b001: this is switch 1 (see the name "sw1p0") - PORT = 0b0000: this is port 0 (see the name "sw1p0") The driver also remembers the "1 -> 100" mapping. In the hotpath, if the sub-VLAN from the tag encodes a non-untagged frame, this mapping is used to create a VLAN hwaccel tag, with the value of 100. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller

net: dsa: sja1105: save/restore VLANs using a delta commit method

2020-05-12T20:08:08Z

Managing the VLAN table that is present in hardware will become very difficult once we add a third operating state (best_effort_vlan_filtering). That is because correct cleanup (not too little, not too much) becomes virtually impossible, when VLANs can be added from the bridge layer, from dsa_8021q for basic tagging, for cross-chip bridging, as well as retagging rules for sub-VLANs and cross-chip sub-VLANs. So we need to rethink VLAN interaction with the switch in a more scalable way. In preparation for that, use the priv->expect_dsa_8021q boolean to classify any VLAN request received through .port_vlan_add or .port_vlan_del towards either one of 2 internal lists: bridge VLANs and dsa_8021q VLANs. Then, implement a central sja1105_build_vlan_table method that creates a VLAN configuration from scratch based on the 2 lists of VLANs kept by the driver, and based on the VLAN awareness state. Currently, if we are VLAN-unaware, install the dsa_8021q VLANs, otherwise the bridge VLANs. Then, implement a delta commit procedure that identifies which VLANs from this new configuration are actually different from the config previously committed to hardware. We apply the delta through the dynamic configuration interface (we don't reset the switch). The result is that the hardware should see the exact sequence of operations as before this patch. This also helps remove the "br" argument passed to dsa_8021q_crosschip_bridge_join, which it was only using to figure out whether it should commit the configuration back to us or not, based on the VLAN awareness state of the bridge. We can simplify that, by always allowing those VLANs inside of our dsa_8021q_vlans list, and committing those to hardware when necessary. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller

net: dsa: tag_8021q: introduce a vid_is_dsa_8021q helper

2020-05-12T20:08:07Z

This function returns a boolean denoting whether the VLAN passed as argument is part of the 1024-3071 range that the dsa_8021q tagging scheme uses. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller

net: dsa: sja1105: implement cross-chip bridging operations

2020-05-11T02:52:33Z

sja1105 uses dsa_8021q for DSA tagging, a format which is VLAN at heart and which is compatible with cascading. A complete description of this tagging format is in net/dsa/tag_8021q.c, but a quick summary is that each external-facing port tags incoming frames with a unique pvid, and this special VLAN is transmitted as tagged towards the inside of the system, and as untagged towards the exterior. The tag encodes the switch id and the source port index. This means that cross-chip bridging for dsa_8021q only entails adding the dsa_8021q pvids of one switch to the RX filter of the other switches. Everything else falls naturally into place, as long as the bottom-end of ports (the leaves in the tree) is comprised exclusively of dsa_8021q-compatible (i.e. sja1105 switches). Otherwise, there would be a chance that a front-panel switch transmits a packet tagged with a dsa_8021q header, header which it wouldn't be able to remove, and which would hence "leak" out. The only use case I tested (due to lack of board availability) was when the sja1105 switches are part of disjoint trees (however, this doesn't change the fact that multiple sja1105 switches still need unique switch identifiers in such a system). But in principle, even "true" single-tree setups (with DSA links) should work just as fine, except for a small change which I can't test: dsa_towards_port should be used instead of dsa_upstream_port (I made the assumption that the routing port that any sja1105 should use towards its neighbours is the CPU port. That might not hold true in other setups). Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski

net: dsa: tag_8021q: replace dsa_8021q_remove_header with __skb_vlan_pop

2020-03-24T23:19:01Z

Not only did this wheel did not need reinventing, but there is also an issue with it: It doesn't remove the VLAN header in a way that preserves the L2 payload checksum when that is being provided by the DSA master hw. It should recalculate checksum both for the push, before removing the header, and for the pull afterwards. But the current implementation is quite dizzying, with pulls followed immediately afterwards by pushes, the memmove is done before the push, etc. This makes a DSA master with RX checksumming offload to print stack traces with the infamous 'hw csum failure' message. So remove the dsa_8021q_remove_header function and replace it with something that actually works with inet checksumming. Fixes: d461933638ae ("net: dsa: tag_8021q: Create helper function for removing VLAN header") Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller

net: dsa: tag_8021q: Create helper function for removing VLAN header

2019-06-08T22:20:39Z

This removes the existing implementation from tag_sja1105, which was partially incorrect (it was not changing the MAC header offset, thereby leaving it to point 4 bytes earlier than it should have). This overwrites the VLAN tag by moving the Ethernet source and destination MACs 4 bytes to the right. Then skb->data (assumed to be pointing immediately after the EtherType) is temporarily pushed to the beginning of the new Ethernet header, the new Ethernet header offset and length are recorded, then skb->data is moved back to where it was. Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller