1 files changed, 72 insertions, 5 deletions

diff --git a/tools/testing/selftests/bpf/progs/kfree_skb.c b/tools/testing/selftests/bpf/progs/kfree_skb.c
index 489319ea1d6a..dcc9feac8338 100644
--- a/tools/testing/selftests/bpf/progs/kfree_skb.c
+++ b/tools/testing/selftests/bpf/progs/kfree_skb.c
@@ -1,6 +1,7 @@
 // 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"
 
@@ -43,6 +44,7 @@ struct sk_buff {
 	refcount_t users;
 	unsigned char *data;
 	char __pkt_type_offset[0];
+	char cb[48];
 };
 
 /* copy arguments from
@@ -57,28 +59,41 @@ 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 +105,66 @@ 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;
+}
+
+static volatile struct {
+	bool fentry_test_ok;
+	bool fexit_test_ok;
+} result;
+
+struct eth_type_trans_args {
+	struct sk_buff *skb;
+	struct net_device *dev;
+	unsigned short protocol; /* return value available to fexit progs */
+};
+
+SEC("fentry/eth_type_trans")
+int fentry_eth_type_trans(struct eth_type_trans_args *ctx)
+{
+	struct sk_buff *skb = ctx->skb;
+	struct net_device *dev = ctx->dev;
+	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;
+}
+
+SEC("fexit/eth_type_trans")
+int fexit_eth_type_trans(struct eth_type_trans_args *ctx)
+{
+	struct sk_buff *skb = ctx->skb;
+	struct net_device *dev = ctx->dev;
+	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 || ctx->protocol != bpf_htons(0x86dd) || ifindex != 1)
+		return 0;
+	result.fexit_test_ok = true;
 	return 0;
 }