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Message-ID: <20191106180215.2175714-1-kafai@fb.com>
Date: Wed, 6 Nov 2019 10:02:15 -0800
From: Martin KaFai Lau <kafai@...com>
To: <bpf@...r.kernel.org>, <netdev@...r.kernel.org>
CC: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
David Miller <davem@...emloft.net>, <kernel-team@...com>
Subject: [PATCH bpf-next 2/2] bpf: Add cb access in kfree_skb test
Access the skb->cb[] in the kfree_skb test.
Signed-off-by: Martin KaFai Lau <kafai@...com>
---
.../selftests/bpf/prog_tests/kfree_skb.c | 54 +++++++++++++++----
tools/testing/selftests/bpf/progs/kfree_skb.c | 25 +++++++--
2 files changed, 63 insertions(+), 16 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/kfree_skb.c b/tools/testing/selftests/bpf/prog_tests/kfree_skb.c
index 430b50de1583..6e6fbfba2322 100644
--- a/tools/testing/selftests/bpf/prog_tests/kfree_skb.c
+++ b/tools/testing/selftests/bpf/prog_tests/kfree_skb.c
@@ -1,15 +1,38 @@
// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
+struct meta {
+ int ifindex;
+ __u32 cb32_0;
+ __u8 cb8_0;
+};
+
+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);
diff --git a/tools/testing/selftests/bpf/progs/kfree_skb.c b/tools/testing/selftests/bpf/progs/kfree_skb.c
index 489319ea1d6a..f769fdbf6725 100644
--- a/tools/testing/selftests/bpf/progs/kfree_skb.c
+++ b/tools/testing/selftests/bpf/progs/kfree_skb.c
@@ -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;
}
--
2.17.1
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