skb does not include enough information to find out receiving
sockets/services and netns/containers on packet drops. In theory
skb->dev tells about netns, but it can get cleared/reused, e.g. by TCP
stack for OOO packet lookup. Similarly, skb->sk often identifies a local
sender, and tells nothing about a receiver.
Allow passing an extra receiving socket to the tracepoint to improve
the visibility on receiving drops.
Signed-off-by: Yan Zhai <yan@cloudflare.com>
---
v4->v5: rename rx_skaddr -> rx_sk as Jesper Dangaard Brouer suggested
v3->v4: adjusted the TP_STRUCT field order to be consistent
v2->v3: fixed drop_monitor function prototype
---
include/trace/events/skb.h | 11 +++++++----
net/core/dev.c | 2 +-
net/core/drop_monitor.c | 9 ++++++---
net/core/skbuff.c | 2 +-
4 files changed, 15 insertions(+), 9 deletions(-)
diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index 07e0715628ec..b877133cd93a 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -24,13 +24,14 @@ DEFINE_DROP_REASON(FN, FN)
TRACE_EVENT(kfree_skb,
TP_PROTO(struct sk_buff *skb, void *location,
- enum skb_drop_reason reason),
+ enum skb_drop_reason reason, struct sock *rx_sk),
- TP_ARGS(skb, location, reason),
+ TP_ARGS(skb, location, reason, rx_sk),
TP_STRUCT__entry(
__field(void *, skbaddr)
__field(void *, location)
+ __field(void *, rx_sk)
__field(unsigned short, protocol)
__field(enum skb_drop_reason, reason)
),
@@ -38,12 +39,14 @@ TRACE_EVENT(kfree_skb,
TP_fast_assign(
__entry->skbaddr = skb;
__entry->location = location;
+ __entry->rx_sk = rx_sk;
__entry->protocol = ntohs(skb->protocol);
__entry->reason = reason;
),
- TP_printk("skbaddr=%p protocol=%u location=%pS reason: %s",
- __entry->skbaddr, __entry->protocol, __entry->location,
+ TP_printk("skbaddr=%p rx_sk=%p protocol=%u location=%pS reason: %s",
+ __entry->skbaddr, __entry->rx_sk, __entry->protocol,
+ __entry->location,
__print_symbolic(__entry->reason,
DEFINE_DROP_REASON(FN, FNe)))
);
diff --git a/net/core/dev.c b/net/core/dev.c
index 85fe8138f3e4..7844227ecbfd 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5233,7 +5233,7 @@ static __latent_entropy void net_tx_action(struct softirq_action *h)
trace_consume_skb(skb, net_tx_action);
else
trace_kfree_skb(skb, net_tx_action,
- get_kfree_skb_cb(skb)->reason);
+ get_kfree_skb_cb(skb)->reason, NULL);
if (skb->fclone != SKB_FCLONE_UNAVAILABLE)
__kfree_skb(skb);
diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index 430ed18f8584..2e0ae3328232 100644
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -109,7 +109,8 @@ static u32 net_dm_queue_len = 1000;
struct net_dm_alert_ops {
void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb,
void *location,
- enum skb_drop_reason reason);
+ enum skb_drop_reason reason,
+ struct sock *rx_sk);
void (*napi_poll_probe)(void *ignore, struct napi_struct *napi,
int work, int budget);
void (*work_item_func)(struct work_struct *work);
@@ -264,7 +265,8 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb,
void *location,
- enum skb_drop_reason reason)
+ enum skb_drop_reason reason,
+ struct sock *rx_sk)
{
trace_drop_common(skb, location);
}
@@ -491,7 +493,8 @@ static const struct net_dm_alert_ops net_dm_alert_summary_ops = {
static void net_dm_packet_trace_kfree_skb_hit(void *ignore,
struct sk_buff *skb,
void *location,
- enum skb_drop_reason reason)
+ enum skb_drop_reason reason,
+ struct sock *rx_sk)
{
ktime_t tstamp = ktime_get_real();
struct per_cpu_dm_data *data;
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 466999a7515e..2854afdd713f 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1203,7 +1203,7 @@ bool __kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason)
if (reason == SKB_CONSUMED)
trace_consume_skb(skb, __builtin_return_address(0));
else
- trace_kfree_skb(skb, __builtin_return_address(0), reason);
+ trace_kfree_skb(skb, __builtin_return_address(0), reason, NULL);
return true;
}
--
2.30.2