Messages in this thread Patch in this message | | | From | menglong8.dong@gmail ... | Subject | [PATCH v3 net-next] net: drop_monitor: support drop reason | Date | Thu, 27 Jan 2022 11:33:56 +0800 |
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From: Menglong Dong <imagedong@tencent.com>
In the commit c504e5c2f964 ("net: skb: introduce kfree_skb_reason()") drop reason is introduced to the tracepoint of kfree_skb. Therefore, drop_monitor is able to report the drop reason to users by netlink.
For now, the number of drop reason is passed to users ( seems it's a little troublesome to pass the drop reason as string ). Therefore, users can do some customized description of the reason.
Signed-off-by: Menglong Dong <imagedong@tencent.com> --- v3: - referring to cb->reason and cb->pc directly in net_dm_packet_report_fill()
v2: - get a pointer to struct net_dm_skb_cb instead of local var for each field --- include/uapi/linux/net_dropmon.h | 1 + net/core/drop_monitor.c | 16 ++++++++++++---- 2 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/include/uapi/linux/net_dropmon.h b/include/uapi/linux/net_dropmon.h index 66048cc5d7b3..b2815166dbc2 100644 --- a/include/uapi/linux/net_dropmon.h +++ b/include/uapi/linux/net_dropmon.h @@ -93,6 +93,7 @@ enum net_dm_attr { NET_DM_ATTR_SW_DROPS, /* flag */ NET_DM_ATTR_HW_DROPS, /* flag */ NET_DM_ATTR_FLOW_ACTION_COOKIE, /* binary */ + NET_DM_ATTR_REASON, /* u32 */ __NET_DM_ATTR_MAX, NET_DM_ATTR_MAX = __NET_DM_ATTR_MAX - 1 diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c index 7b288a121a41..11448110f65d 100644 --- a/net/core/drop_monitor.c +++ b/net/core/drop_monitor.c @@ -126,6 +126,7 @@ struct net_dm_skb_cb { struct devlink_trap_metadata *hw_metadata; void *pc; }; + enum skb_drop_reason reason; }; #define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0])) @@ -498,6 +499,7 @@ static void net_dm_packet_trace_kfree_skb_hit(void *ignore, { ktime_t tstamp = ktime_get_real(); struct per_cpu_dm_data *data; + struct net_dm_skb_cb *cb; struct sk_buff *nskb; unsigned long flags; @@ -508,7 +510,9 @@ static void net_dm_packet_trace_kfree_skb_hit(void *ignore, if (!nskb) return; - NET_DM_SKB_CB(nskb)->pc = location; + cb = NET_DM_SKB_CB(nskb); + cb->reason = reason; + cb->pc = location; /* Override the timestamp because we care about the time when the * packet was dropped. */ @@ -606,7 +610,7 @@ static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex, static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb, size_t payload_len) { - u64 pc = (u64)(uintptr_t) NET_DM_SKB_CB(skb)->pc; + struct net_dm_skb_cb *cb = NET_DM_SKB_CB(skb); char buf[NET_DM_MAX_SYMBOL_LEN]; struct nlattr *attr; void *hdr; @@ -620,10 +624,14 @@ static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb, if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW)) goto nla_put_failure; - if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, pc, NET_DM_ATTR_PAD)) + if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, (u64)(uintptr_t)cb->pc, + NET_DM_ATTR_PAD)) goto nla_put_failure; - snprintf(buf, sizeof(buf), "%pS", NET_DM_SKB_CB(skb)->pc); + if (nla_put_u32(msg, NET_DM_ATTR_REASON, cb->reason)) + goto nla_put_failure; + + snprintf(buf, sizeof(buf), "%pS", cb->pc); if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf)) goto nla_put_failure; -- 2.34.1
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