From 9d802da40b7c820deb9c60fc394457ea565cafc8 Mon Sep 17 00:00:00 2001 From: Adrian Moreno Date: Fri, 11 Aug 2023 16:12:48 +0200 Subject: net: openvswitch: add last-action drop reason Create a new drop reason subsystem for openvswitch and add the first drop reason to represent last-action drops. Last-action drops happen when a flow has an empty action list or there is no action that consumes the packet (output, userspace, recirc, etc). It is the most common way in which OVS drops packets. Implementation-wise, most of these skb-consuming actions already call "consume_skb" internally and return directly from within the do_execute_actions() loop so with minimal changes we can assume that any skb that exits the loop normally is a packet drop. Signed-off-by: Adrian Moreno Signed-off-by: David S. Miller --- net/openvswitch/actions.c | 12 ++++++++++-- net/openvswitch/datapath.c | 16 ++++++++++++++++ net/openvswitch/drop.h | 31 +++++++++++++++++++++++++++++++ 3 files changed, 57 insertions(+), 2 deletions(-) create mode 100644 net/openvswitch/drop.h (limited to 'net') diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c index cab1e02b63e0..8c8a7a82f76f 100644 --- a/net/openvswitch/actions.c +++ b/net/openvswitch/actions.c @@ -27,6 +27,7 @@ #include #include "datapath.h" +#include "drop.h" #include "flow.h" #include "conntrack.h" #include "vport.h" @@ -1036,7 +1037,7 @@ static int sample(struct datapath *dp, struct sk_buff *skb, if ((arg->probability != U32_MAX) && (!arg->probability || get_random_u32() > arg->probability)) { if (last) - consume_skb(skb); + ovs_kfree_skb_reason(skb, OVS_DROP_LAST_ACTION); return 0; } @@ -1297,6 +1298,9 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb, if (trace_ovs_do_execute_action_enabled()) trace_ovs_do_execute_action(dp, skb, key, a, rem); + /* Actions that rightfully have to consume the skb should do it + * and return directly. + */ switch (nla_type(a)) { case OVS_ACTION_ATTR_OUTPUT: { int port = nla_get_u32(a); @@ -1332,6 +1336,10 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb, output_userspace(dp, skb, key, a, attr, len, OVS_CB(skb)->cutlen); OVS_CB(skb)->cutlen = 0; + if (nla_is_last(a, rem)) { + consume_skb(skb); + return 0; + } break; case OVS_ACTION_ATTR_HASH: @@ -1485,7 +1493,7 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb, } } - consume_skb(skb); + ovs_kfree_skb_reason(skb, OVS_DROP_LAST_ACTION); return 0; } diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c index a6d2a0b1aa21..d33cb739883f 100644 --- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c @@ -41,6 +41,7 @@ #include #include "datapath.h" +#include "drop.h" #include "flow.h" #include "flow_table.h" #include "flow_netlink.h" @@ -2702,6 +2703,17 @@ static struct pernet_operations ovs_net_ops = { .size = sizeof(struct ovs_net), }; +static const char * const ovs_drop_reasons[] = { +#define S(x) (#x), + OVS_DROP_REASONS(S) +#undef S +}; + +static struct drop_reason_list drop_reason_list_ovs = { + .reasons = ovs_drop_reasons, + .n_reasons = ARRAY_SIZE(ovs_drop_reasons), +}; + static int __init dp_init(void) { int err; @@ -2743,6 +2755,9 @@ static int __init dp_init(void) if (err < 0) goto error_unreg_netdev; + drop_reasons_register_subsys(SKB_DROP_REASON_SUBSYS_OPENVSWITCH, + &drop_reason_list_ovs); + return 0; error_unreg_netdev: @@ -2769,6 +2784,7 @@ static void dp_cleanup(void) ovs_netdev_exit(); unregister_netdevice_notifier(&ovs_dp_device_notifier); unregister_pernet_device(&ovs_net_ops); + drop_reasons_unregister_subsys(SKB_DROP_REASON_SUBSYS_OPENVSWITCH); rcu_barrier(); ovs_vport_exit(); ovs_flow_exit(); diff --git a/net/openvswitch/drop.h b/net/openvswitch/drop.h new file mode 100644 index 000000000000..a5b2b901249b --- /dev/null +++ b/net/openvswitch/drop.h @@ -0,0 +1,31 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * OpenvSwitch drop reason list. + */ + +#ifndef OPENVSWITCH_DROP_H +#define OPENVSWITCH_DROP_H +#include +#include + +#define OVS_DROP_REASONS(R) \ + R(OVS_DROP_LAST_ACTION) \ + /* deliberate comment for trailing \ */ + +enum ovs_drop_reason { + __OVS_DROP_REASON = SKB_DROP_REASON_SUBSYS_OPENVSWITCH << + SKB_DROP_REASON_SUBSYS_SHIFT, +#define ENUM(x) x, + OVS_DROP_REASONS(ENUM) +#undef ENUM + + OVS_DROP_MAX, +}; + +static inline void +ovs_kfree_skb_reason(struct sk_buff *skb, enum ovs_drop_reason reason) +{ + kfree_skb_reason(skb, (u32)reason); +} + +#endif /* OPENVSWITCH_DROP_H */ -- cgit