[ +Martin, bpf ]
On 9/19/23 4:59 PM, Victor Nogueira wrote:
Currently there is no way to distinguish between an error and a
classification verdict. This patch adds the verdict field as a part of
struct tcf_result. That way, tcf_classify can return a proper
error number when it fails, and we keep the classification result
information encapsulated in struct tcf_result.
Also add values SKB_DROP_REASON_TC_EGRESS_ERROR and
SKB_DROP_REASON_TC_INGRESS_ERROR to enum skb_drop_reason.
With that we can distinguish between a drop from a processing error versus
a drop from classification.
Signed-off-by: Victor Nogueira <victor@xxxxxxxxxxxx>
---
include/net/dropreason-core.h | 6 +++++
include/net/sch_generic.h | 7 ++++++
net/core/dev.c | 42 ++++++++++++++++++++++++++---------
net/sched/cls_api.c | 38 ++++++++++++++++++++-----------
net/sched/sch_cake.c | 32 +++++++++++++-------------
net/sched/sch_drr.c | 33 +++++++++++++--------------
net/sched/sch_ets.c | 6 +++--
net/sched/sch_fq_codel.c | 29 ++++++++++++------------
net/sched/sch_fq_pie.c | 28 +++++++++++------------
net/sched/sch_hfsc.c | 6 +++--
net/sched/sch_htb.c | 6 +++--
net/sched/sch_multiq.c | 6 +++--
net/sched/sch_prio.c | 7 ++++--
net/sched/sch_qfq.c | 34 +++++++++++++---------------
net/sched/sch_sfb.c | 29 ++++++++++++------------
net/sched/sch_sfq.c | 28 +++++++++++------------
16 files changed, 195 insertions(+), 142 deletions(-)
diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h
index a587e83fc169..b1c069c8e7f2 100644
--- a/include/net/dropreason-core.h
+++ b/include/net/dropreason-core.h
@@ -80,6 +80,8 @@
FN(IPV6_NDISC_BAD_OPTIONS) \
FN(IPV6_NDISC_NS_OTHERHOST) \
FN(QUEUE_PURGE) \
+ FN(TC_EGRESS_ERROR) \
+ FN(TC_INGRESS_ERROR) \
FNe(MAX)
/**
@@ -345,6 +347,10 @@ enum skb_drop_reason {
SKB_DROP_REASON_IPV6_NDISC_NS_OTHERHOST,
/** @SKB_DROP_REASON_QUEUE_PURGE: bulk free. */
SKB_DROP_REASON_QUEUE_PURGE,
+ /** @SKB_DROP_REASON_TC_EGRESS_ERROR: dropped in TC egress HOOK due to error */
+ SKB_DROP_REASON_TC_EGRESS_ERROR,
+ /** @SKB_DROP_REASON_TC_INGRESS_ERROR: dropped in TC ingress HOOK due to error */
+ SKB_DROP_REASON_TC_INGRESS_ERROR,
/**
* @SKB_DROP_REASON_MAX: the maximum of core drop reasons, which
* shouldn't be used as a real 'reason' - only for tracing code gen
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index f232512505f8..9a3f71d2545e 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -326,6 +326,7 @@ struct Qdisc_ops {
struct tcf_result {
+ u32 verdict;
union {
struct {
unsigned long class;
@@ -336,6 +337,12 @@ struct tcf_result {
};
};
+static inline void tcf_result_set_verdict(struct tcf_result *res,
+ const u32 verdict)
+{
+ res->verdict = verdict;
+}
+
struct tcf_chain;
struct tcf_proto_ops {
diff --git a/net/core/dev.c b/net/core/dev.c
index ccff2b6ef958..1450f4741d9b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3910,31 +3910,39 @@ EXPORT_SYMBOL_GPL(netdev_xmit_skip_txqueue);
#endif /* CONFIG_NET_EGRESS */
#ifdef CONFIG_NET_XGRESS
-static int tc_run(struct tcx_entry *entry, struct sk_buff *skb)
+static int tc_run(struct tcx_entry *entry, struct sk_buff *skb,
+ struct tcf_result *res)
{
- int ret = TC_ACT_UNSPEC;
+ int ret = 0;
#ifdef CONFIG_NET_CLS_ACT
struct mini_Qdisc *miniq = rcu_dereference_bh(entry->miniq);
- struct tcf_result res;
- if (!miniq)
+ if (!miniq) {
+ tcf_result_set_verdict(res, TC_ACT_UNSPEC);
return ret;
+ }
tc_skb_cb(skb)->mru = 0;
tc_skb_cb(skb)->post_ct = false;
mini_qdisc_bstats_cpu_update(miniq, skb);
- ret = tcf_classify(skb, miniq->block, miniq->filter_list, &res, false);
+ ret = tcf_classify(skb, miniq->block, miniq->filter_list, res, false);
+ if (ret < 0) {
+ mini_qdisc_qstats_cpu_drop(miniq);
+ return ret;
+ }
/* Only tcf related quirks below. */
- switch (ret) {
+ switch (res->verdict) {
case TC_ACT_SHOT:
mini_qdisc_qstats_cpu_drop(miniq);
break;
case TC_ACT_OK:
case TC_ACT_RECLASSIFY:
- skb->tc_index = TC_H_MIN(res.classid);
+ skb->tc_index = TC_H_MIN(res->classid);
break;
}
+#else
+ tcf_result_set_verdict(res, TC_ACT_UNSPEC);
#endif /* CONFIG_NET_CLS_ACT */
return ret;
}
@@ -3977,6 +3985,7 @@ sch_handle_ingress(struct sk_buff *skb, struct packet_type **pt_prev, int *ret,
struct net_device *orig_dev, bool *another)
{
struct bpf_mprog_entry *entry = rcu_dereference_bh(skb->dev->tcx_ingress);
+ struct tcf_result res = {0};
int sch_ret;
if (!entry)
@@ -3994,9 +4003,14 @@ sch_handle_ingress(struct sk_buff *skb, struct packet_type **pt_prev, int *ret,
if (sch_ret != TC_ACT_UNSPEC)
goto ingress_verdict;
}
- sch_ret = tc_run(tcx_entry(entry), skb);
+ sch_ret = tc_run(tcx_entry(entry), skb, &res);
+ if (sch_ret < 0) {
+ kfree_skb_reason(skb, SKB_DROP_REASON_TC_INGRESS_ERROR);
+ *ret = NET_RX_DROP;
+ return NULL;
+ }
ingress_verdict:
- switch (sch_ret) {
+ switch (res.verdict) {
This breaks tcx, please move all this logic into tc_run(). No changes to sch_handle_ingress()
or sch_handle_egress should be necessary, you can then just remap the return code to TC_ACT_SHOT
in such case.
case TC_ACT_REDIRECT:
/* skb_mac_header check was done by BPF, so we can safely
* push the L2 header back before redirecting to another
@@ -4032,6 +4046,7 @@ static __always_inline struct sk_buff *
sch_handle_egress(struct sk_buff *skb, int *ret, struct net_device *dev)
{
struct bpf_mprog_entry *entry = rcu_dereference_bh(dev->tcx_egress);
+ struct tcf_result res = {0};
int sch_ret;
if (!entry)
@@ -4045,9 +4060,14 @@ sch_handle_egress(struct sk_buff *skb, int *ret, struct net_device *dev)
if (sch_ret != TC_ACT_UNSPEC)
goto egress_verdict;
}
- sch_ret = tc_run(tcx_entry(entry), skb);
+ sch_ret = tc_run(tcx_entry(entry), skb, &res);
+ if (sch_ret < 0) {
+ kfree_skb_reason(skb, SKB_DROP_REASON_TC_EGRESS_ERROR);
+ *ret = NET_XMIT_DROP;
+ return NULL;
+ }
egress_verdict:
- switch (sch_ret) {
+ switch (res.verdict) {
case TC_ACT_REDIRECT:
/* No need to push/pop skb's mac_header here on egress! */
skb_do_redirect(skb);
