[PATCH net] octeontx2-pf: fix FLOW_DIS_IS_FRAGMENT implementation

From: Asbjørn Sloth Tønnesen
Date: Wed Apr 10 2024 - 09:53:10 EST


Upon reviewing the flower control flags handling in
this driver, I notice that the key wasn't being used,
only the mask.

Ie. `tc flower ... ip_flags nofrag` was hardware
offloaded as `... ip_flags frag`.

Only compile tested, no access to HW.

Fixes: c672e3727989 ("octeontx2-pf: Add support to filter packet based on IP fragment")
Signed-off-by: Asbjørn Sloth Tønnesen <ast@xxxxxxxxxxx>
---

This is a best guess on a fix, I don't know if it will work,
but hopefully someone at Marvell can test it.

The more certain alternative would be to set an error msg.
and return -EOPNOTSUPP, when `tc flower ip_flags nofrag`
is used.

drivers/net/ethernet/marvell/octeontx2/nic/otx2_tc.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_tc.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_tc.c
index 87bdb93cb066e..f4655a8c0705d 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_tc.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_tc.c
@@ -688,22 +688,25 @@ static int otx2_tc_prepare_flow(struct otx2_nic *nic, struct otx2_tc_flow *node,
}

if (flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_CONTROL)) {
struct flow_match_control match;
+ u32 val;

flow_rule_match_control(rule, &match);
if (match.mask->flags & FLOW_DIS_FIRST_FRAG) {
NL_SET_ERR_MSG_MOD(extack, "HW doesn't support frag first/later");
return -EOPNOTSUPP;
}

if (match.mask->flags & FLOW_DIS_IS_FRAGMENT) {
+ val = match.key->flags & FLOW_DIS_IS_FRAGMENT;
if (ntohs(flow_spec->etype) == ETH_P_IP) {
- flow_spec->ip_flag = IPV4_FLAG_MORE;
+ flow_spec->ip_flag = val ? IPV4_FLAG_MORE : 0;
flow_mask->ip_flag = IPV4_FLAG_MORE;
req->features |= BIT_ULL(NPC_IPFRAG_IPV4);
} else if (ntohs(flow_spec->etype) == ETH_P_IPV6) {
- flow_spec->next_header = IPPROTO_FRAGMENT;
+ flow_spec->next_header = val ?
+ IPPROTO_FRAGMENT : 0;
flow_mask->next_header = 0xff;
req->features |= BIT_ULL(NPC_IPFRAG_IPV6);
} else {
NL_SET_ERR_MSG_MOD(extack, "flow-type should be either IPv4 and IPv6");
--
2.43.0