Commit dcfe7673 authored by Vladimir Oltean's avatar Vladimir Oltean Committed by Jakub Kicinski
Browse files

net: dsa: tag_sja1105: absorb logic for not overwriting precise info into dsa_8021q_rcv() 



In both sja1105_rcv() and sja1110_rcv(), we may have precise source port
information coming from parallel hardware mechanisms, in addition to the
tag_8021q header.

Only sja1105_rcv() has extra logic to not overwrite that precise info
with what's present in the VLAN tag. This is because sja1110_rcv() gets
by, by having a reversed set of checks when assigning skb->dev. When the
source port is imprecise (vbid >=1), source_port and switch_id will be
set to zeroes by dsa_8021q_rcv(), which might be problematic. But by
checking for vbid >= 1 first, sja1110_rcv() fends that off.

We would like to make more code common between sja1105_rcv() and
sja1110_rcv(), and for that, we need to make sure that sja1110_rcv()
also goes through the precise source port preservation logic.

Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: default avatarPawel Dembicki <paweldembicki@gmail.com>
Reviewed-by: default avatarVladimir Oltean <olteanv@gmail.com>
Tested-by: default avatarVladimir Oltean <olteanv@gmail.com>
Link: https://patch.msgid.link/20240713211620.1125910-4-paweldembicki@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 6b783ded

net/dsa/tag_8021q.c

+29 −3
Original line number Diff line number Diff line
@@ -497,9 +497,21 @@ struct net_device *dsa_tag_8021q_find_port_by_vbid(struct net_device *conduit, 
}

EXPORT_SYMBOL_GPL(dsa_tag_8021q_find_port_by_vbid);



/**

 * dsa_8021q_rcv - Decode source information from tag_8021q header

 * @skb: RX socket buffer

 * @source_port: pointer to storage for precise source port information.

 *	If this is known already from outside tag_8021q, the pre-initialized

 *	value is preserved. If not known, pass -1.

 * @switch_id: similar to source_port.

 * @vbid: pointer to storage for imprecise bridge ID. Must be pre-initialized

 *	with -1. If a positive value is returned, the source_port and switch_id

 *	are invalid.

 */

void dsa_8021q_rcv(struct sk_buff *skb, int *source_port, int *switch_id,

		   int *vbid)

{

	int tmp_source_port, tmp_switch_id, tmp_vbid;

	u16 vid, tci;



	if (skb_vlan_tag_present(skb)) {
@@ -513,11 +525,25 @@ void dsa_8021q_rcv(struct sk_buff *skb, int *source_port, int *switch_id, 


	vid = tci & VLAN_VID_MASK;



	*source_port = dsa_8021q_rx_source_port(vid);

	*switch_id = dsa_8021q_rx_switch_id(vid);

	tmp_source_port = dsa_8021q_rx_source_port(vid);

	tmp_switch_id = dsa_8021q_rx_switch_id(vid);

	tmp_vbid = dsa_tag_8021q_rx_vbid(vid);



	/* Precise source port information is unknown when receiving from a

	 * VLAN-unaware bridging domain, and tmp_source_port and tmp_switch_id

	 * are zeroes in this case.

	 *

	 * Preserve the source information from hardware-specific mechanisms,

	 * if available. This allows us to not overwrite a valid source port

	 * and switch ID with less precise values.

	 */

	if (tmp_vbid == 0 && *source_port == -1)

		*source_port = tmp_source_port;

	if (tmp_vbid == 0 && *switch_id == -1)

		*switch_id = tmp_switch_id;



	if (vbid)

		*vbid = dsa_tag_8021q_rx_vbid(vid);

		*vbid = tmp_vbid;



	skb->priority = (tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;

}

net/dsa/tag_sja1105.c

+3 −20
Original line number Diff line number Diff line
@@ -524,30 +524,13 @@ static struct sk_buff *sja1105_rcv(struct sk_buff *skb, 
	/* Normal data plane traffic and link-local frames are tagged with

	 * a tag_8021q VLAN which we have to strip

	 */

	if (sja1105_skb_has_tag_8021q(skb)) {

		int tmp_source_port = -1, tmp_switch_id = -1;



		sja1105_vlan_rcv(skb, &tmp_source_port, &tmp_switch_id, &vbid,

				 &vid);

		/* Preserve the source information from the INCL_SRCPT option,

		 * if available. This allows us to not overwrite a valid source

		 * port and switch ID with zeroes when receiving link-local

		 * frames from a VLAN-unaware bridged port (non-zero vbid) or a

		 * VLAN-aware bridged port (non-zero vid). Furthermore, the

		 * tag_8021q source port information is only of trust when the

		 * vbid is 0 (precise port). Otherwise, tmp_source_port and

		 * tmp_switch_id will be zeroes.

		 */

		if (vbid == 0 && source_port == -1)

			source_port = tmp_source_port;

		if (vbid == 0 && switch_id == -1)

			switch_id = tmp_switch_id;

	} else if (source_port == -1 && switch_id == -1) {

	if (sja1105_skb_has_tag_8021q(skb))

		sja1105_vlan_rcv(skb, &source_port, &switch_id, &vbid, &vid);

	else if (source_port == -1 && switch_id == -1)

		/* Packets with no source information have no chance of

		 * getting accepted, drop them straight away.

		 */

		return NULL;

	}



	if (source_port != -1 && switch_id != -1)

		skb->dev = dsa_conduit_find_user(netdev, switch_id, source_port);