From: Vlad Buslov vladbu@nvidia.com
[ Upstream commit 2105f700b53c24aa48b65c15652acc386044d26a ]
A tc flower filter matching TCA_FLOWER_KEY_VLAN_ETH_TYPE is expected to match the L2 ethertype following the first VLAN header, as confirmed by linked discussion with the maintainer. However, such rule also matches packets that have additional second VLAN header, even though filter has both eth_type and vlan_ethtype set to "ipv4". Looking at the code this seems to be mostly an artifact of the way flower uses flow dissector. First, even though looking at the uAPI eth_type and vlan_ethtype appear like a distinct fields, in flower they are all mapped to the same key->basic.n_proto. Second, flow dissector skips following VLAN header as no keys for FLOW_DISSECTOR_KEY_CVLAN are set and eventually assigns the value of n_proto to last parsed header. With these, such filters ignore any headers present between first VLAN header and first "non magic" header (ipv4 in this case) that doesn't result FLOW_DISSECT_RET_PROTO_AGAIN.
Fix the issue by extending flow dissector VLAN key structure with new 'vlan_eth_type' field that matches first ethertype following previously parsed VLAN header. Modify flower classifier to set the new flow_dissector_key_vlan->vlan_eth_type with value obtained from TCA_FLOWER_KEY_VLAN_ETH_TYPE/TCA_FLOWER_KEY_CVLAN_ETH_TYPE uAPIs.
Link: https://lore.kernel.org/all/Yjhgi48BpTGh6dig@nanopsycho/ Fixes: 9399ae9a6cb2 ("net_sched: flower: Add vlan support") Fixes: d64efd0926ba ("net/sched: flower: Add supprt for matching on QinQ vlan headers") Signed-off-by: Vlad Buslov vladbu@nvidia.com Reviewed-by: Jiri Pirko jiri@nvidia.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/flow_dissector.h | 2 ++ net/core/flow_dissector.c | 1 + net/sched/cls_flower.c | 18 +++++++++++++----- 3 files changed, 16 insertions(+), 5 deletions(-)
diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h index 99f8580344d0..01229084b3ed 100644 --- a/include/net/flow_dissector.h +++ b/include/net/flow_dissector.h @@ -50,6 +50,8 @@ struct flow_dissector_key_vlan { u16 vlan_id:12, vlan_priority:3; __be16 vlan_tpid; + __be16 vlan_eth_type; + u16 padding; };
struct flow_dissector_key_mpls { diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 949694c70cbc..da860a680256 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -827,6 +827,7 @@ bool __skb_flow_dissect(const struct sk_buff *skb, VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT; } key_vlan->vlan_tpid = saved_vlan_tpid; + key_vlan->vlan_eth_type = proto; }
fdret = FLOW_DISSECT_RET_PROTO_AGAIN; diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c index 208436eb107c..6163648145c1 100644 --- a/net/sched/cls_flower.c +++ b/net/sched/cls_flower.c @@ -554,6 +554,7 @@ static int fl_set_key_mpls(struct nlattr **tb, static void fl_set_key_vlan(struct nlattr **tb, __be16 ethertype, int vlan_id_key, int vlan_prio_key, + int vlan_next_eth_type_key, struct flow_dissector_key_vlan *key_val, struct flow_dissector_key_vlan *key_mask) { @@ -572,6 +573,11 @@ static void fl_set_key_vlan(struct nlattr **tb, } key_val->vlan_tpid = ethertype; key_mask->vlan_tpid = cpu_to_be16(~0); + if (tb[vlan_next_eth_type_key]) { + key_val->vlan_eth_type = + nla_get_be16(tb[vlan_next_eth_type_key]); + key_mask->vlan_eth_type = cpu_to_be16(~0); + } }
static void fl_set_key_flag(u32 flower_key, u32 flower_mask, @@ -801,8 +807,9 @@ static int fl_set_key(struct net *net, struct nlattr **tb,
if (eth_type_vlan(ethertype)) { fl_set_key_vlan(tb, ethertype, TCA_FLOWER_KEY_VLAN_ID, - TCA_FLOWER_KEY_VLAN_PRIO, &key->vlan, - &mask->vlan); + TCA_FLOWER_KEY_VLAN_PRIO, + TCA_FLOWER_KEY_VLAN_ETH_TYPE, + &key->vlan, &mask->vlan);
if (tb[TCA_FLOWER_KEY_VLAN_ETH_TYPE]) { ethertype = nla_get_be16(tb[TCA_FLOWER_KEY_VLAN_ETH_TYPE]); @@ -810,6 +817,7 @@ static int fl_set_key(struct net *net, struct nlattr **tb, fl_set_key_vlan(tb, ethertype, TCA_FLOWER_KEY_CVLAN_ID, TCA_FLOWER_KEY_CVLAN_PRIO, + TCA_FLOWER_KEY_CVLAN_ETH_TYPE, &key->cvlan, &mask->cvlan); fl_set_key_val(tb, &key->basic.n_proto, TCA_FLOWER_KEY_CVLAN_ETH_TYPE, @@ -1717,13 +1725,13 @@ static int fl_dump_key(struct sk_buff *skb, struct net *net, goto nla_put_failure;
if (mask->basic.n_proto) { - if (mask->cvlan.vlan_tpid) { + if (mask->cvlan.vlan_eth_type) { if (nla_put_be16(skb, TCA_FLOWER_KEY_CVLAN_ETH_TYPE, key->basic.n_proto)) goto nla_put_failure; - } else if (mask->vlan.vlan_tpid) { + } else if (mask->vlan.vlan_eth_type) { if (nla_put_be16(skb, TCA_FLOWER_KEY_VLAN_ETH_TYPE, - key->basic.n_proto)) + key->vlan.vlan_eth_type)) goto nla_put_failure; } }