diff mbox series

[RFC,v5,5/5] net_sched: introduce helper bpf_skb_tc_classify()

Message ID 20220602041028.95124-6-xiyou.wangcong@gmail.com (mailing list archive)
State RFC
Delegated to: BPF
Headers show
Series net_sched: introduce eBPF based Qdisc | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-VM_Test-1 fail Logs for Kernel LATEST on ubuntu-latest with gcc
bpf/vmtest-bpf-next-VM_Test-2 fail Logs for Kernel LATEST on ubuntu-latest with llvm-15
bpf/vmtest-bpf-next-PR fail PR summary
bpf/vmtest-bpf-next-VM_Test-3 fail Logs for Kernel LATEST on z15 with gcc
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix warning Target tree name not specified in the subject
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit fail Errors and warnings before: 1807 this patch: 1809
netdev/cc_maintainers warning 14 maintainers not CCed: kafai@fb.com jhs@mojatatu.com daniel@iogearbox.net songliubraving@fb.com jiri@resnulli.us ast@kernel.org pabeni@redhat.com yhs@fb.com edumazet@google.com davem@davemloft.net john.fastabend@gmail.com kuba@kernel.org andrii@kernel.org kpsingh@kernel.org
netdev/build_clang success Errors and warnings before: 212 this patch: 212
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn fail Errors and warnings before: 1817 this patch: 1819
netdev/checkpatch warning WARNING: line length of 81 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/tree_selection success Guessing tree name failed - patch did not apply, async

Commit Message

Cong Wang June 2, 2022, 4:10 a.m. UTC 
From: Cong Wang <cong.wang@bytedance.com>

Introduce an eBPF helper function bpf_skb_tc_classify() to reuse exising
TC filters on *any* Qdisc to classify the skb.

Signed-off-by: Cong Wang <cong.wang@bytedance.com>
---
 include/uapi/linux/bpf.h |  1 +
 net/core/filter.c        |  5 +++
 net/sched/cls_api.c      | 69 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 75 insertions(+)
diff mbox series

Patch

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 148ec0c4e643..ad65859abbd5 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5462,6 +5462,7 @@  union bpf_attr {
 	FN(skb_map_pop),		\
 	FN(flow_map_push),		\
 	FN(flow_map_pop),		\
+	FN(skb_tc_classify),		\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
diff --git a/net/core/filter.c b/net/core/filter.c
index 1205298a17ca..8bd8cf5d5d20 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -7817,6 +7817,7 @@  const struct bpf_func_proto bpf_skb_map_push_proto __weak;
 const struct bpf_func_proto bpf_skb_map_pop_proto __weak;
 const struct bpf_func_proto bpf_flow_map_push_proto __weak;
 const struct bpf_func_proto bpf_flow_map_pop_proto __weak;
+const struct bpf_func_proto bpf_skb_tc_classify_proto __weak;
 
 static const struct bpf_func_proto *
 tc_qdisc_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
@@ -7830,6 +7831,10 @@  tc_qdisc_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_flow_map_push_proto;
 	case BPF_FUNC_flow_map_pop:
 		return &bpf_flow_map_pop_proto;
+#ifdef CONFIG_NET_CLS_ACT
+	case BPF_FUNC_skb_tc_classify:
+		return &bpf_skb_tc_classify_proto;
+#endif
 	default:
 		return tc_cls_act_func_proto(func_id, prog);
 	}
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 9bb4d3dcc994..86a78265bc31 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -22,6 +22,7 @@ 
 #include <linux/idr.h>
 #include <linux/jhash.h>
 #include <linux/rculist.h>
+#include <linux/filter.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
 #include <net/netlink.h>
@@ -1654,6 +1655,74 @@  int tcf_classify(struct sk_buff *skb,
 }
 EXPORT_SYMBOL(tcf_classify);
 
+#ifdef CONFIG_BPF_SYSCALL
+BPF_CALL_3(bpf_skb_tc_classify, struct sk_buff *, skb, int, ifindex, u32, handle)
+{
+	struct net *net = dev_net(skb->dev);
+	const struct Qdisc_class_ops *cops;
+	struct tcf_result res = {};
+	struct tcf_block *block;
+	struct tcf_chain *chain;
+	struct net_device *dev;
+	unsigned long cl = 0;
+	struct Qdisc *q;
+	int result;
+
+	rcu_read_lock();
+	dev = dev_get_by_index_rcu(net, ifindex);
+	if (!dev)
+		goto out;
+	q = qdisc_lookup_rcu(dev, handle);
+	if (!q)
+		goto out;
+
+	cops = q->ops->cl_ops;
+	if (!cops)
+		goto out;
+	if (!cops->tcf_block)
+		goto out;
+	if (TC_H_MIN(handle)) {
+		cl = cops->find(q, handle);
+		if (cl == 0)
+			goto out;
+	}
+	block = cops->tcf_block(q, cl, NULL);
+	if (!block)
+		goto out;
+
+	for (chain = tcf_get_next_chain(block, NULL);
+	     chain;
+	     chain = tcf_get_next_chain(block, chain)) {
+		struct tcf_proto *tp;
+
+		result = tcf_classify(skb, NULL, tp, &res, false);
+		if (result  >= 0) {
+			switch (result) {
+			case TC_ACT_QUEUED:
+			case TC_ACT_STOLEN:
+			case TC_ACT_TRAP:
+				fallthrough;
+			case TC_ACT_SHOT:
+				rcu_read_unlock();
+				return 0;
+			}
+		}
+	}
+out:
+	rcu_read_unlock();
+	return res.class;
+}
+
+const struct bpf_func_proto bpf_skb_tc_classify_proto = {
+	.func		= bpf_skb_tc_classify,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_ANYTHING,
+};
+#endif
+
 struct tcf_chain_info {
 	struct tcf_proto __rcu **pprev;
 	struct tcf_proto __rcu *next;