From cd11b164073b719203318227918f9510809d5e10 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Mon, 30 Jul 2018 14:30:44 +0200 Subject: [PATCH] net/tc: introduce TC_ACT_REINSERT. This is similar TC_ACT_REDIRECT, but with a slightly different semantic: - on ingress the mirred skbs are passed to the target device network stack without any additional check not scrubbing. - the rcu-protected stats provided via the tcf_result struct are updated on error conditions. This new tcfa_action value is not exposed to the user-space and can be used only internally by clsact. v1 -> v2: do not touch TC_ACT_REDIRECT code path, introduce a new action type instead v2 -> v3: - rename the new action value TC_ACT_REINJECT, update the helper accordingly - take care of uncloned reinjected packets in XDP generic hook v3 -> v4: - renamed again the new action value (JiriP) v4 -> v5: - fix build error with !NET_CLS_ACT (kbuild bot) Signed-off-by: Paolo Abeni Acked-by: Jiri Pirko Signed-off-by: David S. Miller --- include/net/pkt_cls.h | 3 +++ include/net/sch_generic.h | 28 ++++++++++++++++++++++++++++ net/core/dev.c | 6 +++++- 3 files changed, 36 insertions(+), 1 deletion(-) diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h index 6d02f31abba8..22bfc3a13c25 100644 --- a/include/net/pkt_cls.h +++ b/include/net/pkt_cls.h @@ -7,6 +7,9 @@ #include #include +/* TC action not accessible from user space */ +#define TC_ACT_REINSERT (TC_ACT_VALUE_MAX + 1) + /* Basic packet classifier frontend definitions. */ struct tcf_walker { diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index bcae181c1857..a6d00093f35e 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -235,6 +235,12 @@ struct tcf_result { u32 classid; }; const struct tcf_proto *goto_tp; + + /* used by the TC_ACT_REINSERT action */ + struct { + bool ingress; + struct gnet_stats_queue *qstats; + }; }; }; @@ -569,6 +575,15 @@ static inline void skb_reset_tc(struct sk_buff *skb) #endif } +static inline bool skb_is_tc_redirected(const struct sk_buff *skb) +{ +#ifdef CONFIG_NET_CLS_ACT + return skb->tc_redirected; +#else + return false; +#endif +} + static inline bool skb_at_tc_ingress(const struct sk_buff *skb) { #ifdef CONFIG_NET_CLS_ACT @@ -1108,4 +1123,17 @@ void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp, void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc, struct mini_Qdisc __rcu **p_miniq); +static inline void skb_tc_reinsert(struct sk_buff *skb, struct tcf_result *res) +{ + struct gnet_stats_queue *stats = res->qstats; + int ret; + + if (res->ingress) + ret = netif_receive_skb(skb); + else + ret = dev_queue_xmit(skb); + if (ret && stats) + qstats_overlimit_inc(res->qstats); +} + #endif diff --git a/net/core/dev.c b/net/core/dev.c index 89031b5fef9f..38b0c414d780 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4252,7 +4252,7 @@ static u32 netif_receive_generic_xdp(struct sk_buff *skb, /* Reinjected packets coming from act_mirred or similar should * not get XDP generic processing. */ - if (skb_cloned(skb)) + if (skb_cloned(skb) || skb_is_tc_redirected(skb)) return XDP_PASS; /* XDP packets must be linear and must have sufficient headroom @@ -4602,6 +4602,10 @@ sch_handle_ingress(struct sk_buff *skb, struct packet_type **pt_prev, int *ret, __skb_push(skb, skb->mac_len); skb_do_redirect(skb); return NULL; + case TC_ACT_REINSERT: + /* this does not scrub the packet, and updates stats on error */ + skb_tc_reinsert(skb, &cl_res); + return NULL; default: break; } -- 2.39.5