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

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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: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Tested-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://patch.msgid.link/20240713211620.1125910-4-paweldembicki@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Vladimir Oltean 2024-07-13 23:16:09 +02:00 committed by Jakub Kicinski
parent 6b783ded36
commit dcfe767378
2 changed files with 32 additions and 23 deletions
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32
net/dsa/tag_8021q.c
View file

@ -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;
}

23
net/dsa/tag_sja1105.c
View file

@ -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);