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Message-Id: <20220124184139.126950750@linuxfoundation.org>
Date: Mon, 24 Jan 2022 19:36:40 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Paul Blakey <paulb@...dia.com>,
Oz Shlomo <ozsh@...dia.com>, Eli Cohen <elic@...dia.com>,
Roi Dayan <roid@...dia.com>,
Saeed Mahameed <saeedm@...dia.com>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.16 0411/1039] net/mlx5e: Fix matching on modified inner ip_ecn bits
From: Paul Blakey <paulb@...dia.com>
[ Upstream commit b6dfff21a170af5c695ebaa153b7f5e297ddca03 ]
Tunnel device follows RFC 6040, and during decapsulation inner
ip_ecn might change depending on inner and outer ip_ecn as follows:
+---------+----------------------------------------+
|Arriving | Arriving Outer Header |
| Inner +---------+---------+---------+----------+
| Header | Not-ECT | ECT(0) | ECT(1) | CE |
+---------+---------+---------+---------+----------+
| Not-ECT | Not-ECT | Not-ECT | Not-ECT | <drop> |
| ECT(0) | ECT(0) | ECT(0) | ECT(1) | CE* |
| ECT(1) | ECT(1) | ECT(1) | ECT(1)* | CE* |
| CE | CE | CE | CE | CE |
+---------+---------+---------+---------+----------+
Cells marked above are changed from original inner packet ip_ecn value.
Tc then matches on the modified inner ip_ecn, but hw offload which
matches the inner ip_ecn value before decap, will fail.
Fix that by mapping all the cases of outer and inner ip_ecn matching,
and only supporting cases where we know inner wouldn't be changed by
decap, or in the outer ip_ecn=CE case, inner ip_ecn didn't matter.
Fixes: bcef735c59f2 ("net/mlx5e: Offload TC matching on tos/ttl for ip tunnels")
Signed-off-by: Paul Blakey <paulb@...dia.com>
Reviewed-by: Oz Shlomo <ozsh@...dia.com>
Reviewed-by: Eli Cohen <elic@...dia.com>
Reviewed-by: Roi Dayan <roid@...dia.com>
Signed-off-by: Saeed Mahameed <saeedm@...dia.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
.../net/ethernet/mellanox/mlx5/core/en_tc.c | 120 +++++++++++++++++-
1 file changed, 116 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index 5e454a14428f2..9b3adaccc9beb 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -1949,6 +1949,111 @@ u8 mlx5e_tc_get_ip_version(struct mlx5_flow_spec *spec, bool outer)
return ip_version;
}
+/* Tunnel device follows RFC 6040, see include/net/inet_ecn.h.
+ * And changes inner ip_ecn depending on inner and outer ip_ecn as follows:
+ * +---------+----------------------------------------+
+ * |Arriving | Arriving Outer Header |
+ * | Inner +---------+---------+---------+----------+
+ * | Header | Not-ECT | ECT(0) | ECT(1) | CE |
+ * +---------+---------+---------+---------+----------+
+ * | Not-ECT | Not-ECT | Not-ECT | Not-ECT | <drop> |
+ * | ECT(0) | ECT(0) | ECT(0) | ECT(1) | CE* |
+ * | ECT(1) | ECT(1) | ECT(1) | ECT(1)* | CE* |
+ * | CE | CE | CE | CE | CE |
+ * +---------+---------+---------+---------+----------+
+ *
+ * Tc matches on inner after decapsulation on tunnel device, but hw offload matches
+ * the inner ip_ecn value before hardware decap action.
+ *
+ * Cells marked are changed from original inner packet ip_ecn value during decap, and
+ * so matching those values on inner ip_ecn before decap will fail.
+ *
+ * The following helper allows offload when inner ip_ecn won't be changed by outer ip_ecn,
+ * except for the outer ip_ecn = CE, where in all cases inner ip_ecn will be changed to CE,
+ * and such we can drop the inner ip_ecn=CE match.
+ */
+
+static int mlx5e_tc_verify_tunnel_ecn(struct mlx5e_priv *priv,
+ struct flow_cls_offload *f,
+ bool *match_inner_ecn)
+{
+ u8 outer_ecn_mask = 0, outer_ecn_key = 0, inner_ecn_mask = 0, inner_ecn_key = 0;
+ struct flow_rule *rule = flow_cls_offload_flow_rule(f);
+ struct netlink_ext_ack *extack = f->common.extack;
+ struct flow_match_ip match;
+
+ *match_inner_ecn = true;
+
+ if (flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_ENC_IP)) {
+ flow_rule_match_enc_ip(rule, &match);
+ outer_ecn_key = match.key->tos & INET_ECN_MASK;
+ outer_ecn_mask = match.mask->tos & INET_ECN_MASK;
+ }
+
+ if (flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_IP)) {
+ flow_rule_match_ip(rule, &match);
+ inner_ecn_key = match.key->tos & INET_ECN_MASK;
+ inner_ecn_mask = match.mask->tos & INET_ECN_MASK;
+ }
+
+ if (outer_ecn_mask != 0 && outer_ecn_mask != INET_ECN_MASK) {
+ NL_SET_ERR_MSG_MOD(extack, "Partial match on enc_tos ecn bits isn't supported");
+ netdev_warn(priv->netdev, "Partial match on enc_tos ecn bits isn't supported");
+ return -EOPNOTSUPP;
+ }
+
+ if (!outer_ecn_mask) {
+ if (!inner_ecn_mask)
+ return 0;
+
+ NL_SET_ERR_MSG_MOD(extack,
+ "Matching on tos ecn bits without also matching enc_tos ecn bits isn't supported");
+ netdev_warn(priv->netdev,
+ "Matching on tos ecn bits without also matching enc_tos ecn bits isn't supported");
+ return -EOPNOTSUPP;
+ }
+
+ if (inner_ecn_mask && inner_ecn_mask != INET_ECN_MASK) {
+ NL_SET_ERR_MSG_MOD(extack,
+ "Partial match on tos ecn bits with match on enc_tos ecn bits isn't supported");
+ netdev_warn(priv->netdev,
+ "Partial match on tos ecn bits with match on enc_tos ecn bits isn't supported");
+ return -EOPNOTSUPP;
+ }
+
+ if (!inner_ecn_mask)
+ return 0;
+
+ /* Both inner and outer have full mask on ecn */
+
+ if (outer_ecn_key == INET_ECN_ECT_1) {
+ /* inner ecn might change by DECAP action */
+
+ NL_SET_ERR_MSG_MOD(extack, "Match on enc_tos ecn = ECT(1) isn't supported");
+ netdev_warn(priv->netdev, "Match on enc_tos ecn = ECT(1) isn't supported");
+ return -EOPNOTSUPP;
+ }
+
+ if (outer_ecn_key != INET_ECN_CE)
+ return 0;
+
+ if (inner_ecn_key != INET_ECN_CE) {
+ /* Can't happen in software, as packet ecn will be changed to CE after decap */
+ NL_SET_ERR_MSG_MOD(extack,
+ "Match on tos enc_tos ecn = CE while match on tos ecn != CE isn't supported");
+ netdev_warn(priv->netdev,
+ "Match on tos enc_tos ecn = CE while match on tos ecn != CE isn't supported");
+ return -EOPNOTSUPP;
+ }
+
+ /* outer ecn = CE, inner ecn = CE, as decap will change inner ecn to CE in anycase,
+ * drop match on inner ecn
+ */
+ *match_inner_ecn = false;
+
+ return 0;
+}
+
static int parse_tunnel_attr(struct mlx5e_priv *priv,
struct mlx5e_tc_flow *flow,
struct mlx5_flow_spec *spec,
@@ -2144,6 +2249,7 @@ static int __parse_cls_flower(struct mlx5e_priv *priv,
struct flow_rule *rule = flow_cls_offload_flow_rule(f);
struct flow_dissector *dissector = rule->match.dissector;
enum fs_flow_table_type fs_type;
+ bool match_inner_ecn = true;
u16 addr_type = 0;
u8 ip_proto = 0;
u8 *match_level;
@@ -2197,6 +2303,10 @@ static int __parse_cls_flower(struct mlx5e_priv *priv,
headers_c = get_match_inner_headers_criteria(spec);
headers_v = get_match_inner_headers_value(spec);
}
+
+ err = mlx5e_tc_verify_tunnel_ecn(priv, f, &match_inner_ecn);
+ if (err)
+ return err;
}
err = mlx5e_flower_parse_meta(filter_dev, f);
@@ -2420,10 +2530,12 @@ static int __parse_cls_flower(struct mlx5e_priv *priv,
struct flow_match_ip match;
flow_rule_match_ip(rule, &match);
- MLX5_SET(fte_match_set_lyr_2_4, headers_c, ip_ecn,
- match.mask->tos & 0x3);
- MLX5_SET(fte_match_set_lyr_2_4, headers_v, ip_ecn,
- match.key->tos & 0x3);
+ if (match_inner_ecn) {
+ MLX5_SET(fte_match_set_lyr_2_4, headers_c, ip_ecn,
+ match.mask->tos & 0x3);
+ MLX5_SET(fte_match_set_lyr_2_4, headers_v, ip_ecn,
+ match.key->tos & 0x3);
+ }
MLX5_SET(fte_match_set_lyr_2_4, headers_c, ip_dscp,
match.mask->tos >> 2);
--
2.34.1
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