bpf: Add cb access in kfree_skb test (ed5941af) · Commits · 戴 / test

tools/testing/selftests/bpf/prog_tests/kfree_skb.c

+43 −11

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0
		#include <test_progs.h>

		struct meta {
		int ifindex;
		__u32 cb32_0;
		__u8 cb8_0;
		};

		static union {
		__u32 cb32[5];
		__u8 cb8[20];
		} cb = {
		.cb32[0] = 0x81828384,
		};

		static void on_sample(void ctx, int cpu, void data, __u32 size)
		{
		int ifindex = (int )data, duration = 0;
		struct ipv6_packet *pkt_v6 = data + 4;
		struct meta meta = (struct meta )data;
		struct ipv6_packet pkt_v6 = data + sizeof(meta);
		int duration = 0;

		if (ifindex != 1)
		if (CHECK(size != 72 + sizeof(*meta), "check_size", "size %u != %zu\n",
		size, 72 + sizeof(*meta)))
		return;
		if (CHECK(meta->ifindex != 1, "check_meta_ifindex",
		"meta->ifindex = %d\n", meta->ifindex))
		/* spurious kfree_skb not on loopback device */
		return;
		if (CHECK(size != 76, "check_size", "size %u != 76\n", size))
		if (CHECK(meta->cb8_0 != cb.cb8[0], "check_cb8_0", "cb8_0 %x != %x\n",
		meta->cb8_0, cb.cb8[0]))
		return;
		if (CHECK(meta->cb32_0 != cb.cb32[0], "check_cb32_0",
		"cb32_0 %x != %x\n",
		meta->cb32_0, cb.cb32[0]))
		return;
		if (CHECK(pkt_v6->eth.h_proto != 0xdd86, "check_eth",
		"h_proto %x\n", pkt_v6->eth.h_proto))
		@@ -26,6 +49,13 @@ static void on_sample(void ctx, int cpu, void data, __u32 size)

		void test_kfree_skb(void)
		{
		struct __sk_buff skb = {};
		struct bpf_prog_test_run_attr tattr = {
		.data_in = &pkt_v6,
		.data_size_in = sizeof(pkt_v6),
		.ctx_in = &skb,
		.ctx_size_in = sizeof(skb),
		};
		struct bpf_prog_load_attr attr = {
		.file = "./kfree_skb.o",
		};
		@@ -36,11 +66,12 @@ void test_kfree_skb(void)
		struct bpf_link *link = NULL;
		struct bpf_map *perf_buf_map;
		struct bpf_program *prog;
		__u32 duration, retval;
		int err, pkt_fd, kfree_skb_fd;
		int err, kfree_skb_fd;
		bool passed = false;
		__u32 duration = 0;

		err = bpf_prog_load("./test_pkt_access.o", BPF_PROG_TYPE_SCHED_CLS, &obj, &pkt_fd);
		err = bpf_prog_load("./test_pkt_access.o", BPF_PROG_TYPE_SCHED_CLS,
		&obj, &tattr.prog_fd);
		if (CHECK(err, "prog_load sched cls", "err %d errno %d\n", err, errno))
		return;

		@@ -66,11 +97,12 @@ void test_kfree_skb(void)
		if (CHECK(IS_ERR(pb), "perf_buf__new", "err %ld\n", PTR_ERR(pb)))
		goto close_prog;

		err = bpf_prog_test_run(pkt_fd, 1, &pkt_v6, sizeof(pkt_v6),
		NULL, NULL, &retval, &duration);
		CHECK(err \|\| retval, "ipv6",
		memcpy(skb.cb, &cb, sizeof(cb));
		err = bpf_prog_test_run_xattr(&tattr);
		duration = tattr.duration;
		CHECK(err \|\| tattr.retval, "ipv6",
		"err %d errno %d retval %d duration %d\n",
		err, errno, retval, duration);
		err, errno, tattr.retval, duration);

		/* read perf buffer */
		err = perf_buffer__poll(pb, 100);

tools/testing/selftests/bpf/progs/kfree_skb.c

+20 −5

Original line number	Diff line number	Diff line
		@@ -43,6 +43,7 @@ struct sk_buff {
		refcount_t users;
		unsigned char *data;
		char __pkt_type_offset[0];
		char cb[48];
		};

		/* copy arguments from
		@@ -57,28 +58,41 @@ struct trace_kfree_skb {
		void *location;
		};

		struct meta {
		int ifindex;
		__u32 cb32_0;
		__u8 cb8_0;
		};

		SEC("tp_btf/kfree_skb")
		int trace_kfree_skb(struct trace_kfree_skb *ctx)
		{
		struct sk_buff *skb = ctx->skb;
		struct net_device *dev;
		int ifindex;
		struct callback_head *ptr;
		void *func;
		int users;
		unsigned char *data;
		unsigned short pkt_data;
		struct meta meta = {};
		char pkt_type;
		__u32 *cb32;
		__u8 *cb8;

		__builtin_preserve_access_index(({
		users = skb->users.refs.counter;
		data = skb->data;
		dev = skb->dev;
		ifindex = dev->ifindex;
		ptr = dev->ifalias->rcuhead.next;
		func = ptr->func;
		cb8 = (__u8 *)&skb->cb;
		cb32 = (__u32 *)&skb->cb;
		}));

		meta.ifindex = _(dev->ifindex);
		meta.cb8_0 = cb8[8];
		meta.cb32_0 = cb32[2];

		bpf_probe_read_kernel(&pkt_type, sizeof(pkt_type), _(&skb->__pkt_type_offset));
		pkt_type &= 7;

		@@ -90,14 +104,15 @@ int trace_kfree_skb(struct trace_kfree_skb *ctx)
		_(skb->len), users, pkt_type);
		bpf_printk("skb->queue_mapping %d\n", _(skb->queue_mapping));
		bpf_printk("dev->ifindex %d data %llx pkt_data %x\n",
		ifindex, data, pkt_data);
		meta.ifindex, data, pkt_data);
		bpf_printk("cb8_0:%x cb32_0:%x\n", meta.cb8_0, meta.cb32_0);

		if (users != 1 \|\| pkt_data != bpf_htons(0x86dd) \|\| ifindex != 1)
		if (users != 1 \|\| pkt_data != bpf_htons(0x86dd) \|\| meta.ifindex != 1)
		/* raw tp ignores return value */
		return 0;

		/* send first 72 byte of the packet to user space */
		bpf_skb_output(skb, &perf_buf_map, (72ull << 32) \| BPF_F_CURRENT_CPU,
		&ifindex, sizeof(ifindex));
		&meta, sizeof(meta));
		return 0;
		}

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