From 7c1f9797e1b55cb14e9e9bcb817b39d06e021fc8 Mon Sep 17 00:00:00 2001 From: Paul Blakey Date: Wed, 16 Jun 2021 10:55:56 +0300 Subject: [PATCH] net/mlx5e: Fix matching on modified inner ip_ecn bits [ 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 | | | 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 Reviewed-by: Oz Shlomo Reviewed-by: Eli Cohen Reviewed-by: Roi Dayan Signed-off-by: Saeed Mahameed Signed-off-by: Sasha Levin --- drivers/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 fa461bc..8b041de 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c @@ -1874,6 +1874,111 @@ 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 | | + * | 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, @@ -2067,6 +2172,7 @@ 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; @@ -2120,6 +2226,10 @@ 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); @@ -2341,10 +2451,12 @@ 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); -- 2.7.4