From 28315f7999870bb56da236f6b4ffce63efcc7897 Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Sun, 11 Aug 2019 10:35:50 +0300 Subject: drop_monitor: Add alert mode operations The next patch is going to add another alert mode in which the dropped packet is notified to user space, instead of only a summary of recent drops. Abstract the differences between the modes by adding alert mode operations. The operations are selected based on the currently configured mode and associated with the probes and the work item just before tracing starts. Signed-off-by: Ido Schimmel Signed-off-by: David S. Miller --- include/uapi/linux/net_dropmon.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include') diff --git a/include/uapi/linux/net_dropmon.h b/include/uapi/linux/net_dropmon.h index 5edbd0a675fd..0fecdedeb6ca 100644 --- a/include/uapi/linux/net_dropmon.h +++ b/include/uapi/linux/net_dropmon.h @@ -62,4 +62,13 @@ enum { * Our group identifiers */ #define NET_DM_GRP_ALERT 1 + +/** + * enum net_dm_alert_mode - Alert mode. + * @NET_DM_ALERT_MODE_SUMMARY: A summary of recent drops is sent to user space. + */ +enum net_dm_alert_mode { + NET_DM_ALERT_MODE_SUMMARY, +}; + #endif -- cgit v1.2.3 From ca30707dee2bc8bc81cfd8b4277fe90f7ca6df1f Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Sun, 11 Aug 2019 10:35:51 +0300 Subject: drop_monitor: Add packet alert mode So far drop monitor supported only one alert mode in which a summary of locations in which packets were recently dropped was sent to user space. This alert mode is sufficient in order to understand that packets were dropped, but lacks information to perform a more detailed analysis. Add a new alert mode in which the dropped packet itself is passed to user space along with metadata: The drop location (as program counter and resolved symbol), ingress netdevice and drop timestamp. More metadata can be added in the future. To avoid performing expensive operations in the context in which kfree_skb() is invoked (can be hard IRQ), the dropped skb is cloned and queued on per-CPU skb drop list. Then, in process context the netlink message is allocated, prepared and finally sent to user space. The per-CPU skb drop list is limited to 1000 skbs to prevent exhausting the system's memory. Subsequent patches will make this limit configurable and also add a counter that indicates how many skbs were tail dropped. Signed-off-by: Ido Schimmel Signed-off-by: David S. Miller --- include/uapi/linux/net_dropmon.h | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) (limited to 'include') diff --git a/include/uapi/linux/net_dropmon.h b/include/uapi/linux/net_dropmon.h index 0fecdedeb6ca..cfaaf75371b8 100644 --- a/include/uapi/linux/net_dropmon.h +++ b/include/uapi/linux/net_dropmon.h @@ -53,6 +53,7 @@ enum { NET_DM_CMD_CONFIG, NET_DM_CMD_START, NET_DM_CMD_STOP, + NET_DM_CMD_PACKET_ALERT, _NET_DM_CMD_MAX, }; @@ -63,12 +64,38 @@ enum { */ #define NET_DM_GRP_ALERT 1 +enum net_dm_attr { + NET_DM_ATTR_UNSPEC, + + NET_DM_ATTR_ALERT_MODE, /* u8 */ + NET_DM_ATTR_PC, /* u64 */ + NET_DM_ATTR_SYMBOL, /* string */ + NET_DM_ATTR_IN_PORT, /* nested */ + NET_DM_ATTR_TIMESTAMP, /* struct timespec */ + NET_DM_ATTR_PROTO, /* u16 */ + NET_DM_ATTR_PAYLOAD, /* binary */ + NET_DM_ATTR_PAD, + + __NET_DM_ATTR_MAX, + NET_DM_ATTR_MAX = __NET_DM_ATTR_MAX - 1 +}; + /** * enum net_dm_alert_mode - Alert mode. * @NET_DM_ALERT_MODE_SUMMARY: A summary of recent drops is sent to user space. + * @NET_DM_ALERT_MODE_PACKET: Each dropped packet is sent to user space along + * with metadata. */ enum net_dm_alert_mode { NET_DM_ALERT_MODE_SUMMARY, + NET_DM_ALERT_MODE_PACKET, +}; + +enum { + NET_DM_ATTR_PORT_NETDEV_IFINDEX, /* u32 */ + + __NET_DM_ATTR_PORT_MAX, + NET_DM_ATTR_PORT_MAX = __NET_DM_ATTR_PORT_MAX - 1 }; #endif -- cgit v1.2.3 From 57986617a736aec2980c1c78a9dd8dcdf477ee6e Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Sun, 11 Aug 2019 10:35:52 +0300 Subject: drop_monitor: Allow truncation of dropped packets When sending dropped packets to user space it is not always necessary to copy the entire packet as usually only the headers are of interest. Allow user to specify the truncation length and add the original length of the packet as additional metadata to the netlink message. By default no truncation is performed. Signed-off-by: Ido Schimmel Signed-off-by: David S. Miller --- include/uapi/linux/net_dropmon.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/uapi/linux/net_dropmon.h b/include/uapi/linux/net_dropmon.h index cfaaf75371b8..5cd7eb1f66ba 100644 --- a/include/uapi/linux/net_dropmon.h +++ b/include/uapi/linux/net_dropmon.h @@ -75,6 +75,8 @@ enum net_dm_attr { NET_DM_ATTR_PROTO, /* u16 */ NET_DM_ATTR_PAYLOAD, /* binary */ NET_DM_ATTR_PAD, + NET_DM_ATTR_TRUNC_LEN, /* u32 */ + NET_DM_ATTR_ORIG_LEN, /* u32 */ __NET_DM_ATTR_MAX, NET_DM_ATTR_MAX = __NET_DM_ATTR_MAX - 1 -- cgit v1.2.3 From 444be061d012f1a8ebf95292a648a4e0e2afa83f Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Sun, 11 Aug 2019 10:35:53 +0300 Subject: drop_monitor: Add a command to query current configuration Users should be able to query the current configuration of drop monitor before they start using it. Add a command to query the existing configuration which currently consists of alert mode and packet truncation length. Signed-off-by: Ido Schimmel Signed-off-by: David S. Miller --- include/uapi/linux/net_dropmon.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/uapi/linux/net_dropmon.h b/include/uapi/linux/net_dropmon.h index 5cd7eb1f66ba..3b765a8428b5 100644 --- a/include/uapi/linux/net_dropmon.h +++ b/include/uapi/linux/net_dropmon.h @@ -54,6 +54,8 @@ enum { NET_DM_CMD_START, NET_DM_CMD_STOP, NET_DM_CMD_PACKET_ALERT, + NET_DM_CMD_CONFIG_GET, + NET_DM_CMD_CONFIG_NEW, _NET_DM_CMD_MAX, }; -- cgit v1.2.3 From 30328d46af593dcf24582f2a431d84ea0cf4bdef Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Sun, 11 Aug 2019 10:35:54 +0300 Subject: drop_monitor: Make drop queue length configurable In packet alert mode, each CPU holds a list of dropped skbs that need to be processed in process context and sent to user space. To avoid exhausting the system's memory the maximum length of this queue is currently set to 1000. Allow users to tune the length of this queue according to their needs. The configured length is reported to user space when drop monitor configuration is queried. Signed-off-by: Ido Schimmel Signed-off-by: David S. Miller --- include/uapi/linux/net_dropmon.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/uapi/linux/net_dropmon.h b/include/uapi/linux/net_dropmon.h index 3b765a8428b5..1d0bdb1ba954 100644 --- a/include/uapi/linux/net_dropmon.h +++ b/include/uapi/linux/net_dropmon.h @@ -79,6 +79,7 @@ enum net_dm_attr { NET_DM_ATTR_PAD, NET_DM_ATTR_TRUNC_LEN, /* u32 */ NET_DM_ATTR_ORIG_LEN, /* u32 */ + NET_DM_ATTR_QUEUE_LEN, /* u32 */ __NET_DM_ATTR_MAX, NET_DM_ATTR_MAX = __NET_DM_ATTR_MAX - 1 -- cgit v1.2.3 From e9feb58020f952f7d9de785ede9a7d54ab1eda5c Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Sun, 11 Aug 2019 10:35:55 +0300 Subject: drop_monitor: Expose tail drop counter Previous patch made the length of the per-CPU skb drop list configurable. Expose a counter that shows how many packets could not be enqueued to this list. This allows users determine the desired queue length. Signed-off-by: Ido Schimmel Signed-off-by: David S. Miller --- include/uapi/linux/net_dropmon.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include') diff --git a/include/uapi/linux/net_dropmon.h b/include/uapi/linux/net_dropmon.h index 1d0bdb1ba954..405b31cbf723 100644 --- a/include/uapi/linux/net_dropmon.h +++ b/include/uapi/linux/net_dropmon.h @@ -56,6 +56,8 @@ enum { NET_DM_CMD_PACKET_ALERT, NET_DM_CMD_CONFIG_GET, NET_DM_CMD_CONFIG_NEW, + NET_DM_CMD_STATS_GET, + NET_DM_CMD_STATS_NEW, _NET_DM_CMD_MAX, }; @@ -80,6 +82,7 @@ enum net_dm_attr { NET_DM_ATTR_TRUNC_LEN, /* u32 */ NET_DM_ATTR_ORIG_LEN, /* u32 */ NET_DM_ATTR_QUEUE_LEN, /* u32 */ + NET_DM_ATTR_STATS, /* nested */ __NET_DM_ATTR_MAX, NET_DM_ATTR_MAX = __NET_DM_ATTR_MAX - 1 @@ -103,4 +106,11 @@ enum { NET_DM_ATTR_PORT_MAX = __NET_DM_ATTR_PORT_MAX - 1 }; +enum { + NET_DM_ATTR_STATS_DROPPED, /* u64 */ + + __NET_DM_ATTR_STATS_MAX, + NET_DM_ATTR_STATS_MAX = __NET_DM_ATTR_STATS_MAX - 1 +}; + #endif -- cgit v1.2.3