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net: mscc: ocelot: allow tc-flower mirred action towards foreign interfaces

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Debugging certain flows in the offloaded switch data path can be done by
installing two tc-mirred filters for mirroring: one in the hardware data
path, which copies the frames to the CPU, and one which takes the frame
from there and mirrors it to a virtual interface like a dummy device,
where it can be seen with tcpdump.

The effect of having 2 filters run on the same packet can be obtained by
default using tc, by not specifying either the 'skip_sw' or 'skip_hw'
keywords.

Instead of refusing to offload mirroring/redirecting packets towards
interfaces that aren't switch ports, just treat every other destination
for what it is: something that is handled in software, behind the CPU
port.

Usage:

$ ip link add dummy0 type dummy; ip link set dummy0 up
$ tc qdisc add dev swp0 clsact
$ tc filter add dev swp0 ingress protocol ip flower action mirred ingress mirror dev dummy0

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20241023135251.1752488-7-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Vladimir Oltean 2024-10-23 16:52:51 +03:00 committed by Jakub Kicinski
parent 3535d70df9
commit 49a09073cb
1 changed files with 42 additions and 12 deletions
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54
drivers/net/ethernet/mscc/ocelot_flower.c
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@ -228,6 +228,32 @@ ocelot_flower_parse_egress_vlan_modify(struct ocelot_vcap_filter *filter,
return 0;
}
static int
ocelot_flower_parse_egress_port(struct ocelot *ocelot, struct flow_cls_offload *f,
const struct flow_action_entry *a, bool mirror,
struct netlink_ext_ack *extack)
{
const char *act_string = mirror ? "mirror" : "redirect";
int egress_port = ocelot->ops->netdev_to_port(a->dev);
enum flow_action_id offloadable_act_id;
offloadable_act_id = mirror ? FLOW_ACTION_MIRRED : FLOW_ACTION_REDIRECT;
/* Mirroring towards foreign interfaces is handled in software */
if (egress_port < 0 || a->id != offloadable_act_id) {
if (f->common.skip_sw) {
NL_SET_ERR_MSG_FMT(extack,
"Can only %s to %s if filter also runs in software",
act_string, egress_port < 0 ?
"CPU" : "ingress of ocelot port");
return -EOPNOTSUPP;
}
egress_port = ocelot->num_phys_ports;
}
return egress_port;
}
static int ocelot_flower_parse_action(struct ocelot *ocelot, int port,
bool ingress, struct flow_cls_offload *f,
struct ocelot_vcap_filter *filter)
@ -356,6 +382,7 @@ static int ocelot_flower_parse_action(struct ocelot *ocelot, int port,
filter->type = OCELOT_VCAP_FILTER_OFFLOAD;
break;
case FLOW_ACTION_REDIRECT:
case FLOW_ACTION_REDIRECT_INGRESS:
if (filter->block_id != VCAP_IS2) {
NL_SET_ERR_MSG_MOD(extack,
"Redirect action can only be offloaded to VCAP IS2");
@ -366,17 +393,19 @@ static int ocelot_flower_parse_action(struct ocelot *ocelot, int port,
"Last action must be GOTO");
return -EOPNOTSUPP;
}
egress_port = ocelot->ops->netdev_to_port(a->dev);
if (egress_port < 0) {
NL_SET_ERR_MSG_MOD(extack,
"Destination not an ocelot port");
return -EOPNOTSUPP;
}
egress_port = ocelot_flower_parse_egress_port(ocelot, f,
a, false,
extack);
if (egress_port < 0)
return egress_port;
filter->action.mask_mode = OCELOT_MASK_MODE_REDIRECT;
filter->action.port_mask = BIT(egress_port);
filter->type = OCELOT_VCAP_FILTER_OFFLOAD;
break;
case FLOW_ACTION_MIRRED:
case FLOW_ACTION_MIRRED_INGRESS:
if (filter->block_id != VCAP_IS2) {
NL_SET_ERR_MSG_MOD(extack,
"Mirror action can only be offloaded to VCAP IS2");
@ -387,12 +416,13 @@ static int ocelot_flower_parse_action(struct ocelot *ocelot, int port,
"Last action must be GOTO");
return -EOPNOTSUPP;
}
egress_port = ocelot->ops->netdev_to_port(a->dev);
if (egress_port < 0) {
NL_SET_ERR_MSG_MOD(extack,
"Destination not an ocelot port");
return -EOPNOTSUPP;
}
egress_port = ocelot_flower_parse_egress_port(ocelot, f,
a, true,
extack);
if (egress_port < 0)
return egress_port;
filter->egress_port.value = egress_port;
filter->action.mirror_ena = true;
filter->type = OCELOT_VCAP_FILTER_OFFLOAD;