net: extend drop reasons for multiple subsystems (071c0fc6) · Commits · EulixOS / Software / Kernel

include/net/dropreason-core.h

+10 −4

Original line number	Diff line number	Diff line
		@@ -340,12 +340,20 @@ enum skb_drop_reason {
		*/
		SKB_DROP_REASON_IPV6_NDISC_NS_OTHERHOST,
		/**
		* @SKB_DROP_REASON_MAX: the maximum of drop reason, which shouldn't be
		* used as a real 'reason'
		* @SKB_DROP_REASON_MAX: the maximum of core drop reasons, which
		* shouldn't be used as a real 'reason' - only for tracing code gen
		*/
		SKB_DROP_REASON_MAX,

		/**
		* @SKB_DROP_REASON_SUBSYS_MASK: subsystem mask in drop reasons,
		* see &enum skb_drop_reason_subsys
		*/
		SKB_DROP_REASON_SUBSYS_MASK = 0xffff0000,
		};

		#define SKB_DROP_REASON_SUBSYS_SHIFT 16

		#define SKB_DR_INIT(name, reason) \
		enum skb_drop_reason name = SKB_DROP_REASON_##reason
		#define SKB_DR(name) \
		@@ -359,6 +367,4 @@ enum skb_drop_reason {
		SKB_DR_SET(name, reason); \
		} while (0)

		extern const char * const drop_reasons[];

		#endif

include/net/dropreason.h

0 → 100644

+31 −0

Original line number	Diff line number	Diff line
		/* SPDX-License-Identifier: GPL-2.0-or-later */

		#ifndef _LINUX_DROPREASON_H
		#define _LINUX_DROPREASON_H
		#include <net/dropreason-core.h>

		/**
		* enum skb_drop_reason_subsys - subsystem tag for (extended) drop reasons
		*/
		enum skb_drop_reason_subsys {
		/** @SKB_DROP_REASON_SUBSYS_CORE: core drop reasons defined above */
		SKB_DROP_REASON_SUBSYS_CORE,

		/** @SKB_DROP_REASON_SUBSYS_NUM: number of subsystems defined */
		SKB_DROP_REASON_SUBSYS_NUM
		};

		struct drop_reason_list {
		const char * const *reasons;
		size_t n_reasons;
		};

		/* Note: due to dynamic registrations, access must be under RCU */
		extern const struct drop_reason_list __rcu *
		drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_NUM];

		void drop_reasons_register_subsys(enum skb_drop_reason_subsys subsys,
		const struct drop_reason_list *list);
		void drop_reasons_unregister_subsys(enum skb_drop_reason_subsys subsys);

		#endif

net/core/drop_monitor.c

+24 −9

Original line number	Diff line number	Diff line
		@@ -21,6 +21,7 @@
		#include <linux/workqueue.h>
		#include <linux/netlink.h>
		#include <linux/net_dropmon.h>
		#include <linux/bitfield.h>
		#include <linux/percpu.h>
		#include <linux/timer.h>
		#include <linux/bitops.h>
		@@ -29,6 +30,7 @@
		#include <net/genetlink.h>
		#include <net/netevent.h>
		#include <net/flow_offload.h>
		#include <net/dropreason.h>
		#include <net/devlink.h>

		#include <trace/events/skb.h>
		@@ -504,8 +506,6 @@ static void net_dm_packet_trace_kfree_skb_hit(void *ignore,
		if (!nskb)
		return;

		if (unlikely(reason >= SKB_DROP_REASON_MAX \|\| reason <= 0))
		reason = SKB_DROP_REASON_NOT_SPECIFIED;
		cb = NET_DM_SKB_CB(nskb);
		cb->reason = reason;
		cb->pc = location;
		@@ -552,9 +552,9 @@ static size_t net_dm_in_port_size(void)
		}

		#define NET_DM_MAX_SYMBOL_LEN 40
		#define NET_DM_MAX_REASON_LEN 50

		static size_t net_dm_packet_report_size(size_t payload_len,
		enum skb_drop_reason reason)
		static size_t net_dm_packet_report_size(size_t payload_len)
		{
		size_t size;

		@@ -576,7 +576,7 @@ static size_t net_dm_packet_report_size(size_t payload_len,
		/* NET_DM_ATTR_PROTO */
		nla_total_size(sizeof(u16)) +
		/* NET_DM_ATTR_REASON */
		nla_total_size(strlen(drop_reasons[reason]) + 1) +
		nla_total_size(NET_DM_MAX_REASON_LEN + 1) +
		/* NET_DM_ATTR_PAYLOAD */
		nla_total_size(payload_len);
		}
		@@ -610,6 +610,8 @@ static int net_dm_packet_report_fill(struct sk_buff msg, struct sk_buff skb,
		size_t payload_len)
		{
		struct net_dm_skb_cb *cb = NET_DM_SKB_CB(skb);
		const struct drop_reason_list *list = NULL;
		unsigned int subsys, subsys_reason;
		char buf[NET_DM_MAX_SYMBOL_LEN];
		struct nlattr *attr;
		void *hdr;
		@@ -627,9 +629,24 @@ static int net_dm_packet_report_fill(struct sk_buff msg, struct sk_buff skb,
		NET_DM_ATTR_PAD))
		goto nla_put_failure;

		rcu_read_lock();
		subsys = u32_get_bits(cb->reason, SKB_DROP_REASON_SUBSYS_MASK);
		if (subsys < SKB_DROP_REASON_SUBSYS_NUM)
		list = rcu_dereference(drop_reasons_by_subsys[subsys]);
		subsys_reason = cb->reason & ~SKB_DROP_REASON_SUBSYS_MASK;
		if (!list \|\|
		subsys_reason >= list->n_reasons \|\|
		!list->reasons[subsys_reason] \|\|
		strlen(list->reasons[subsys_reason]) > NET_DM_MAX_REASON_LEN) {
		list = rcu_dereference(drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_CORE]);
		subsys_reason = SKB_DROP_REASON_NOT_SPECIFIED;
		}
		if (nla_put_string(msg, NET_DM_ATTR_REASON,
		drop_reasons[cb->reason]))
		list->reasons[subsys_reason])) {
		rcu_read_unlock();
		goto nla_put_failure;
		}
		rcu_read_unlock();

		snprintf(buf, sizeof(buf), "%pS", cb->pc);
		if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf))
		@@ -687,9 +704,7 @@ static void net_dm_packet_report(struct sk_buff *skb)
		if (net_dm_trunc_len)
		payload_len = min_t(size_t, net_dm_trunc_len, payload_len);

		msg = nlmsg_new(net_dm_packet_report_size(payload_len,
		NET_DM_SKB_CB(skb)->reason),
		GFP_KERNEL);
		msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL);
		if (!msg)
		goto out;

net/core/skbuff.c

+56 −3

Original line number	Diff line number	Diff line
		@@ -58,6 +58,7 @@
		#include <linux/scatterlist.h>
		#include <linux/errqueue.h>
		#include <linux/prefetch.h>
		#include <linux/bitfield.h>
		#include <linux/if_vlan.h>
		#include <linux/mpls.h>
		#include <linux/kcov.h>
		@@ -72,6 +73,7 @@
		#include <net/mptcp.h>
		#include <net/mctp.h>
		#include <net/page_pool.h>
		#include <net/dropreason.h>

		#include <linux/uaccess.h>
		#include <trace/events/skb.h>
		@@ -122,11 +124,59 @@ EXPORT_SYMBOL(sysctl_max_skb_frags);

		#undef FN
		#define FN(reason) [SKB_DROP_REASON_##reason] = #reason,
		const char * const drop_reasons[] = {
		static const char * const drop_reasons[] = {
		[SKB_CONSUMED] = "CONSUMED",
		DEFINE_DROP_REASON(FN, FN)
		};
		EXPORT_SYMBOL(drop_reasons);

		static const struct drop_reason_list drop_reasons_core = {
		.reasons = drop_reasons,
		.n_reasons = ARRAY_SIZE(drop_reasons),
		};

		const struct drop_reason_list __rcu *
		drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_NUM] = {
		[SKB_DROP_REASON_SUBSYS_CORE] = RCU_INITIALIZER(&drop_reasons_core),
		};
		EXPORT_SYMBOL(drop_reasons_by_subsys);

		/**
		* drop_reasons_register_subsys - register another drop reason subsystem
		* @subsys: the subsystem to register, must not be the core
		* @list: the list of drop reasons within the subsystem, must point to
		* a statically initialized list
		*/
		void drop_reasons_register_subsys(enum skb_drop_reason_subsys subsys,
		const struct drop_reason_list *list)
		{
		if (WARN(subsys <= SKB_DROP_REASON_SUBSYS_CORE \|\|
		subsys >= ARRAY_SIZE(drop_reasons_by_subsys),
		"invalid subsystem %d\n", subsys))
		return;

		/* must point to statically allocated memory, so INIT is OK */
		RCU_INIT_POINTER(drop_reasons_by_subsys[subsys], list);
		}
		EXPORT_SYMBOL_GPL(drop_reasons_register_subsys);

		/**
		* drop_reasons_unregister_subsys - unregister a drop reason subsystem
		* @subsys: the subsystem to remove, must not be the core
		*
		* Note: This will synchronize_rcu() to ensure no users when it returns.
		*/
		void drop_reasons_unregister_subsys(enum skb_drop_reason_subsys subsys)
		{
		if (WARN(subsys <= SKB_DROP_REASON_SUBSYS_CORE \|\|
		subsys >= ARRAY_SIZE(drop_reasons_by_subsys),
		"invalid subsystem %d\n", subsys))
		return;

		RCU_INIT_POINTER(drop_reasons_by_subsys[subsys], NULL);

		synchronize_rcu();
		}
		EXPORT_SYMBOL_GPL(drop_reasons_unregister_subsys);

		/**
		* skb_panic - private function for out-of-line support
		@@ -986,7 +1036,10 @@ bool __kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason)
		if (unlikely(!skb_unref(skb)))
		return false;

		DEBUG_NET_WARN_ON_ONCE(reason <= 0 \|\| reason >= SKB_DROP_REASON_MAX);
		DEBUG_NET_WARN_ON_ONCE(reason == SKB_NOT_DROPPED_YET \|\|
		u32_get_bits(reason,
		SKB_DROP_REASON_SUBSYS_MASK) >=
		SKB_DROP_REASON_SUBSYS_NUM);

		if (reason == SKB_CONSUMED)
		trace_consume_skb(skb, __builtin_return_address(0));