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Diffstat (limited to 'tools/testing/selftests/bpf/progs/kfree_skb.c')
-rw-r--r--tools/testing/selftests/bpf/progs/kfree_skb.c153
1 files changed, 153 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/kfree_skb.c b/tools/testing/selftests/bpf/progs/kfree_skb.c
new file mode 100644
index 000000000000..974d6f3bb319
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kfree_skb.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Facebook
+#include <linux/bpf.h>
+#include <stdbool.h>
+#include "bpf_helpers.h"
+#include "bpf_endian.h"
+#include "bpf_trace_helpers.h"
+
+char _license[] SEC("license") = "GPL";
+struct {
+ __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
+ __uint(key_size, sizeof(int));
+ __uint(value_size, sizeof(int));
+} perf_buf_map SEC(".maps");
+
+#define _(P) (__builtin_preserve_access_index(P))
+
+/* define few struct-s that bpf program needs to access */
+struct callback_head {
+ struct callback_head *next;
+ void (*func)(struct callback_head *head);
+};
+struct dev_ifalias {
+ struct callback_head rcuhead;
+};
+
+struct net_device /* same as kernel's struct net_device */ {
+ int ifindex;
+ struct dev_ifalias *ifalias;
+};
+
+typedef struct {
+ int counter;
+} atomic_t;
+typedef struct refcount_struct {
+ atomic_t refs;
+} refcount_t;
+
+struct sk_buff {
+ /* field names and sizes should match to those in the kernel */
+ unsigned int len, data_len;
+ __u16 mac_len, hdr_len, queue_mapping;
+ struct net_device *dev;
+ /* order of the fields doesn't matter */
+ refcount_t users;
+ unsigned char *data;
+ char __pkt_type_offset[0];
+ char cb[48];
+};
+
+struct meta {
+ int ifindex;
+ __u32 cb32_0;
+ __u8 cb8_0;
+};
+
+/* TRACE_EVENT(kfree_skb,
+ * TP_PROTO(struct sk_buff *skb, void *location),
+ */
+BPF_TRACE_2("tp_btf/kfree_skb", trace_kfree_skb,
+ struct sk_buff *, skb, void *, location)
+{
+ struct net_device *dev;
+ 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;
+ 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;
+
+ /* read eth proto */
+ bpf_probe_read_kernel(&pkt_data, sizeof(pkt_data), data + 12);
+
+ bpf_printk("rcuhead.next %llx func %llx\n", ptr, func);
+ bpf_printk("skb->len %d users %d pkt_type %x\n",
+ _(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",
+ 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) || 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,
+ &meta, sizeof(meta));
+ return 0;
+}
+
+static volatile struct {
+ bool fentry_test_ok;
+ bool fexit_test_ok;
+} result;
+
+BPF_TRACE_3("fentry/eth_type_trans", fentry_eth_type_trans,
+ struct sk_buff *, skb, struct net_device *, dev,
+ unsigned short, protocol)
+{
+ int len, ifindex;
+
+ __builtin_preserve_access_index(({
+ len = skb->len;
+ ifindex = dev->ifindex;
+ }));
+
+ /* fentry sees full packet including L2 header */
+ if (len != 74 || ifindex != 1)
+ return 0;
+ result.fentry_test_ok = true;
+ return 0;
+}
+
+BPF_TRACE_3("fexit/eth_type_trans", fexit_eth_type_trans,
+ struct sk_buff *, skb, struct net_device *, dev,
+ unsigned short, protocol)
+{
+ int len, ifindex;
+
+ __builtin_preserve_access_index(({
+ len = skb->len;
+ ifindex = dev->ifindex;
+ }));
+
+ /* fexit sees packet without L2 header that eth_type_trans should have
+ * consumed.
+ */
+ if (len != 60 || protocol != bpf_htons(0x86dd) || ifindex != 1)
+ return 0;
+ result.fexit_test_ok = true;
+ return 0;
+}