diff mbox series

[v2,bpf] selftests/bpf: Test bpf_skb_adjust_room on CHECKSUM_PARTIAL

Message ID 20221221014914.3543155-1-martin.lau@linux.dev (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series [v2,bpf] selftests/bpf: Test bpf_skb_adjust_room on CHECKSUM_PARTIAL | expand

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Commit Message

Martin KaFai Lau Dec. 21, 2022, 1:49 a.m. UTC 
From: Martin KaFai Lau <martin.lau@kernel.org>

When the bpf_skb_adjust_room() shrinks the skb such that
its csum_start is invalid, the skb->ip_summed should
be reset from CHECKSUM_PARTIAL to CHECKSUM_NONE.

The commit 54c3f1a81421 ("bpf: pull before calling skb_postpull_rcsum()")
fixed it.

This patch adds a test to ensure the skb->ip_summed changed
from CHECKSUM_PARTIAL to CHECKSUM_NONE after bpf_skb_adjust_room().

Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
---
v2: Add test to DENYLIST.s390x due to kfunc usage

 tools/testing/selftests/bpf/DENYLIST.s390x    |  1 +
 .../selftests/bpf/prog_tests/decap_sanity.c   | 83 +++++++++++++++++++
 .../selftests/bpf/progs/bpf_tracing_net.h     |  6 ++
 .../selftests/bpf/progs/decap_sanity.c        | 68 +++++++++++++++
 4 files changed, 158 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/decap_sanity.c
 create mode 100644 tools/testing/selftests/bpf/progs/decap_sanity.c

Comments

Andrii Nakryiko Dec. 21, 2022, 5:05 a.m. UTC | #1 
On Tue, Dec 20, 2022 at 5:49 PM Martin KaFai Lau <martin.lau@linux.dev> wrote:
>
> From: Martin KaFai Lau <martin.lau@kernel.org>
>
> When the bpf_skb_adjust_room() shrinks the skb such that
> its csum_start is invalid, the skb->ip_summed should
> be reset from CHECKSUM_PARTIAL to CHECKSUM_NONE.
>
> The commit 54c3f1a81421 ("bpf: pull before calling skb_postpull_rcsum()")
> fixed it.
>
> This patch adds a test to ensure the skb->ip_summed changed
> from CHECKSUM_PARTIAL to CHECKSUM_NONE after bpf_skb_adjust_room().
>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
> ---
> v2: Add test to DENYLIST.s390x due to kfunc usage
>
>  tools/testing/selftests/bpf/DENYLIST.s390x    |  1 +
>  .../selftests/bpf/prog_tests/decap_sanity.c   | 83 +++++++++++++++++++
>  .../selftests/bpf/progs/bpf_tracing_net.h     |  6 ++
>  .../selftests/bpf/progs/decap_sanity.c        | 68 +++++++++++++++
>  4 files changed, 158 insertions(+)
>  create mode 100644 tools/testing/selftests/bpf/prog_tests/decap_sanity.c
>  create mode 100644 tools/testing/selftests/bpf/progs/decap_sanity.c
>
> diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x
> index 585fcf73c731..dba6c027920d 100644
> --- a/tools/testing/selftests/bpf/DENYLIST.s390x
> +++ b/tools/testing/selftests/bpf/DENYLIST.s390x
> @@ -86,3 +86,4 @@ xdp_bpf2bpf                              # failed to auto-attach program 'trace_
>  xdp_do_redirect                          # prog_run_max_size unexpected error: -22 (errno 22)
>  xdp_synproxy                             # JIT does not support calling kernel function                                (kfunc)
>  xfrm_info                                # JIT does not support calling kernel function                                (kfunc)
> +decap_sanity                             # JIT does not support calling kernel function                                (kfunc)

let's keep this list sorted?

> \ No newline at end of file
> diff --git a/tools/testing/selftests/bpf/prog_tests/decap_sanity.c b/tools/testing/selftests/bpf/prog_tests/decap_sanity.c
> new file mode 100644
> index 000000000000..2fbb3017b740
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/decap_sanity.c
> @@ -0,0 +1,83 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
> +
> +#include <sys/types.h>
> +#include <sys/socket.h>
> +#include <net/if.h>
> +#include <linux/in6.h>
> +
> +#include "test_progs.h"
> +#include "network_helpers.h"
> +#include "decap_sanity.skel.h"
> +
> +#define SYS(fmt, ...)                                          \
> +       ({                                                      \
> +               char cmd[1024];                                 \
> +               snprintf(cmd, sizeof(cmd), fmt, ##__VA_ARGS__); \
> +               if (!ASSERT_OK(system(cmd), cmd))               \
> +                       goto fail;                              \
> +       })
> +
> +#define NS_TEST "decap_sanity_ns"
> +#define IPV6_IFACE_ADDR "face::1"
> +#define UDP_TEST_PORT 7777
> +
> +void test_decap_sanity(void)
> +{
> +       LIBBPF_OPTS(bpf_tc_hook, qdisc_hook, .attach_point = BPF_TC_EGRESS);
> +       LIBBPF_OPTS(bpf_tc_opts, tc_attach);
> +       struct nstoken *nstoken = NULL;
> +       struct decap_sanity *skel;
> +       struct sockaddr_in6 addr;
> +       socklen_t addrlen;
> +       char buf[128] = {};
> +       int sockfd, err;
> +
> +       skel = decap_sanity__open_and_load();
> +       if (!ASSERT_OK_PTR(skel, "skel open_and_load"))
> +               return;
> +
> +       SYS("ip netns add %s", NS_TEST);
> +       SYS("ip -net %s -6 addr add %s/128 dev lo nodad", NS_TEST, IPV6_IFACE_ADDR);
> +       SYS("ip -net %s link set dev lo up", NS_TEST);
> +
> +       nstoken = open_netns(NS_TEST);
> +       if (!ASSERT_OK_PTR(nstoken, "open_netns"))
> +               goto fail;
> +
> +       qdisc_hook.ifindex = if_nametoindex("lo");
> +       if (!ASSERT_GT(qdisc_hook.ifindex, 0, "if_nametoindex lo"))
> +               goto fail;
> +
> +       err = bpf_tc_hook_create(&qdisc_hook);
> +       if (!ASSERT_OK(err, "create qdisc hook"))
> +               goto fail;

you seem to be missing bpf_tc_hook_destroy() for clean up

> +
> +       tc_attach.prog_fd = bpf_program__fd(skel->progs.decap_sanity);
> +       err = bpf_tc_attach(&qdisc_hook, &tc_attach);
> +       if (!ASSERT_OK(err, "attach filter"))
> +               goto fail;
> +
> +       addrlen = sizeof(addr);
> +       err = make_sockaddr(AF_INET6, IPV6_IFACE_ADDR, UDP_TEST_PORT,
> +                           (void *)&addr, &addrlen);
> +       if (!ASSERT_OK(err, "make_sockaddr"))
> +               goto fail;
> +       sockfd = socket(AF_INET6, SOCK_DGRAM, 0);
> +       if (!ASSERT_NEQ(sockfd, -1, "socket"))
> +               goto fail;
> +       err = sendto(sockfd, buf, sizeof(buf), 0, (void *)&addr, addrlen);
> +       close(sockfd);
> +       if (!ASSERT_EQ(err, sizeof(buf), "send"))
> +               goto fail;
> +
> +       ASSERT_EQ(skel->bss->init_csum_partial, true, "init_csum_partial");
> +       ASSERT_EQ(skel->bss->final_csum_none, true, "final_csum_none");
> +       ASSERT_EQ(skel->bss->broken_csum_start, false, "broken_csum_start");

ASSERT_TRUE and ASSERT_FALSE ?

> +
> +fail:
> +       if (nstoken)
> +               close_netns(nstoken);
> +       system("ip netns del " NS_TEST " >& /dev/null");
> +       decap_sanity__destroy(skel);
> +}

[...]
Martin KaFai Lau Dec. 21, 2022, 5:58 p.m. UTC | #2 
On 12/20/22 9:05 PM, Andrii Nakryiko wrote:
> On Tue, Dec 20, 2022 at 5:49 PM Martin KaFai Lau <martin.lau@linux.dev> wrote:
>>
>> From: Martin KaFai Lau <martin.lau@kernel.org>
>>
>> When the bpf_skb_adjust_room() shrinks the skb such that
>> its csum_start is invalid, the skb->ip_summed should
>> be reset from CHECKSUM_PARTIAL to CHECKSUM_NONE.
>>
>> The commit 54c3f1a81421 ("bpf: pull before calling skb_postpull_rcsum()")
>> fixed it.
>>
>> This patch adds a test to ensure the skb->ip_summed changed
>> from CHECKSUM_PARTIAL to CHECKSUM_NONE after bpf_skb_adjust_room().
>>
>> Cc: Jakub Kicinski <kuba@kernel.org>
>> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
>> ---
>> v2: Add test to DENYLIST.s390x due to kfunc usage
>>
>>   tools/testing/selftests/bpf/DENYLIST.s390x    |  1 +
>>   .../selftests/bpf/prog_tests/decap_sanity.c   | 83 +++++++++++++++++++
>>   .../selftests/bpf/progs/bpf_tracing_net.h     |  6 ++
>>   .../selftests/bpf/progs/decap_sanity.c        | 68 +++++++++++++++
>>   4 files changed, 158 insertions(+)
>>   create mode 100644 tools/testing/selftests/bpf/prog_tests/decap_sanity.c
>>   create mode 100644 tools/testing/selftests/bpf/progs/decap_sanity.c
>>
>> diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x
>> index 585fcf73c731..dba6c027920d 100644
>> --- a/tools/testing/selftests/bpf/DENYLIST.s390x
>> +++ b/tools/testing/selftests/bpf/DENYLIST.s390x
>> @@ -86,3 +86,4 @@ xdp_bpf2bpf                              # failed to auto-attach program 'trace_
>>   xdp_do_redirect                          # prog_run_max_size unexpected error: -22 (errno 22)
>>   xdp_synproxy                             # JIT does not support calling kernel function                                (kfunc)
>>   xfrm_info                                # JIT does not support calling kernel function                                (kfunc)
>> +decap_sanity                             # JIT does not support calling kernel function                                (kfunc)
> 
> let's keep this list sorted?

Ack.

> 
>> \ No newline at end of file
>> diff --git a/tools/testing/selftests/bpf/prog_tests/decap_sanity.c b/tools/testing/selftests/bpf/prog_tests/decap_sanity.c
>> new file mode 100644
>> index 000000000000..2fbb3017b740
>> --- /dev/null
>> +++ b/tools/testing/selftests/bpf/prog_tests/decap_sanity.c
>> @@ -0,0 +1,83 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
>> +
>> +#include <sys/types.h>
>> +#include <sys/socket.h>
>> +#include <net/if.h>
>> +#include <linux/in6.h>
>> +
>> +#include "test_progs.h"
>> +#include "network_helpers.h"
>> +#include "decap_sanity.skel.h"
>> +
>> +#define SYS(fmt, ...)                                          \
>> +       ({                                                      \
>> +               char cmd[1024];                                 \
>> +               snprintf(cmd, sizeof(cmd), fmt, ##__VA_ARGS__); \
>> +               if (!ASSERT_OK(system(cmd), cmd))               \
>> +                       goto fail;                              \
>> +       })
>> +
>> +#define NS_TEST "decap_sanity_ns"
>> +#define IPV6_IFACE_ADDR "face::1"
>> +#define UDP_TEST_PORT 7777
>> +
>> +void test_decap_sanity(void)
>> +{
>> +       LIBBPF_OPTS(bpf_tc_hook, qdisc_hook, .attach_point = BPF_TC_EGRESS);
>> +       LIBBPF_OPTS(bpf_tc_opts, tc_attach);
>> +       struct nstoken *nstoken = NULL;
>> +       struct decap_sanity *skel;
>> +       struct sockaddr_in6 addr;
>> +       socklen_t addrlen;
>> +       char buf[128] = {};
>> +       int sockfd, err;
>> +
>> +       skel = decap_sanity__open_and_load();
>> +       if (!ASSERT_OK_PTR(skel, "skel open_and_load"))
>> +               return;
>> +
>> +       SYS("ip netns add %s", NS_TEST);
>> +       SYS("ip -net %s -6 addr add %s/128 dev lo nodad", NS_TEST, IPV6_IFACE_ADDR);
>> +       SYS("ip -net %s link set dev lo up", NS_TEST);
>> +
>> +       nstoken = open_netns(NS_TEST);
>> +       if (!ASSERT_OK_PTR(nstoken, "open_netns"))
>> +               goto fail;
>> +
>> +       qdisc_hook.ifindex = if_nametoindex("lo");
>> +       if (!ASSERT_GT(qdisc_hook.ifindex, 0, "if_nametoindex lo"))
>> +               goto fail;
>> +
>> +       err = bpf_tc_hook_create(&qdisc_hook);
>> +       if (!ASSERT_OK(err, "create qdisc hook"))
>> +               goto fail;
> 
> you seem to be missing bpf_tc_hook_destroy() for clean up

It will go away with the 'ip netns del' at the end of the test, so not needed.
I will add a comment at the end of this function to make it clear.

> 
>> +
>> +       tc_attach.prog_fd = bpf_program__fd(skel->progs.decap_sanity);
>> +       err = bpf_tc_attach(&qdisc_hook, &tc_attach);
>> +       if (!ASSERT_OK(err, "attach filter"))
>> +               goto fail;
>> +
>> +       addrlen = sizeof(addr);
>> +       err = make_sockaddr(AF_INET6, IPV6_IFACE_ADDR, UDP_TEST_PORT,
>> +                           (void *)&addr, &addrlen);
>> +       if (!ASSERT_OK(err, "make_sockaddr"))
>> +               goto fail;
>> +       sockfd = socket(AF_INET6, SOCK_DGRAM, 0);
>> +       if (!ASSERT_NEQ(sockfd, -1, "socket"))
>> +               goto fail;
>> +       err = sendto(sockfd, buf, sizeof(buf), 0, (void *)&addr, addrlen);
>> +       close(sockfd);
>> +       if (!ASSERT_EQ(err, sizeof(buf), "send"))
>> +               goto fail;
>> +
>> +       ASSERT_EQ(skel->bss->init_csum_partial, true, "init_csum_partial");
>> +       ASSERT_EQ(skel->bss->final_csum_none, true, "final_csum_none");
>> +       ASSERT_EQ(skel->bss->broken_csum_start, false, "broken_csum_start");
> 
> ASSERT_TRUE and ASSERT_FALSE ?

Ack.

Thanks for the review.

> 
>> +
>> +fail:
>> +       if (nstoken)
>> +               close_netns(nstoken);
>> +       system("ip netns del " NS_TEST " >& /dev/null");
>> +       decap_sanity__destroy(skel);
>> +}
> 
> [...]
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x
index 585fcf73c731..dba6c027920d 100644
--- a/tools/testing/selftests/bpf/DENYLIST.s390x
+++ b/tools/testing/selftests/bpf/DENYLIST.s390x
@@ -86,3 +86,4 @@  xdp_bpf2bpf                              # failed to auto-attach program 'trace_
 xdp_do_redirect                          # prog_run_max_size unexpected error: -22 (errno 22)
 xdp_synproxy                             # JIT does not support calling kernel function                                (kfunc)
 xfrm_info                                # JIT does not support calling kernel function                                (kfunc)
+decap_sanity                             # JIT does not support calling kernel function                                (kfunc)
\ No newline at end of file
diff --git a/tools/testing/selftests/bpf/prog_tests/decap_sanity.c b/tools/testing/selftests/bpf/prog_tests/decap_sanity.c
new file mode 100644
index 000000000000..2fbb3017b740
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/decap_sanity.c
@@ -0,0 +1,83 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <net/if.h>
+#include <linux/in6.h>
+
+#include "test_progs.h"
+#include "network_helpers.h"
+#include "decap_sanity.skel.h"
+
+#define SYS(fmt, ...)						\
+	({							\
+		char cmd[1024];					\
+		snprintf(cmd, sizeof(cmd), fmt, ##__VA_ARGS__);	\
+		if (!ASSERT_OK(system(cmd), cmd))		\
+			goto fail;				\
+	})
+
+#define NS_TEST "decap_sanity_ns"
+#define IPV6_IFACE_ADDR "face::1"
+#define UDP_TEST_PORT 7777
+
+void test_decap_sanity(void)
+{
+	LIBBPF_OPTS(bpf_tc_hook, qdisc_hook, .attach_point = BPF_TC_EGRESS);
+	LIBBPF_OPTS(bpf_tc_opts, tc_attach);
+	struct nstoken *nstoken = NULL;
+	struct decap_sanity *skel;
+	struct sockaddr_in6 addr;
+	socklen_t addrlen;
+	char buf[128] = {};
+	int sockfd, err;
+
+	skel = decap_sanity__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel open_and_load"))
+		return;
+
+	SYS("ip netns add %s", NS_TEST);
+	SYS("ip -net %s -6 addr add %s/128 dev lo nodad", NS_TEST, IPV6_IFACE_ADDR);
+	SYS("ip -net %s link set dev lo up", NS_TEST);
+
+	nstoken = open_netns(NS_TEST);
+	if (!ASSERT_OK_PTR(nstoken, "open_netns"))
+		goto fail;
+
+	qdisc_hook.ifindex = if_nametoindex("lo");
+	if (!ASSERT_GT(qdisc_hook.ifindex, 0, "if_nametoindex lo"))
+		goto fail;
+
+	err = bpf_tc_hook_create(&qdisc_hook);
+	if (!ASSERT_OK(err, "create qdisc hook"))
+		goto fail;
+
+	tc_attach.prog_fd = bpf_program__fd(skel->progs.decap_sanity);
+	err = bpf_tc_attach(&qdisc_hook, &tc_attach);
+	if (!ASSERT_OK(err, "attach filter"))
+		goto fail;
+
+	addrlen = sizeof(addr);
+	err = make_sockaddr(AF_INET6, IPV6_IFACE_ADDR, UDP_TEST_PORT,
+			    (void *)&addr, &addrlen);
+	if (!ASSERT_OK(err, "make_sockaddr"))
+		goto fail;
+	sockfd = socket(AF_INET6, SOCK_DGRAM, 0);
+	if (!ASSERT_NEQ(sockfd, -1, "socket"))
+		goto fail;
+	err = sendto(sockfd, buf, sizeof(buf), 0, (void *)&addr, addrlen);
+	close(sockfd);
+	if (!ASSERT_EQ(err, sizeof(buf), "send"))
+		goto fail;
+
+	ASSERT_EQ(skel->bss->init_csum_partial, true, "init_csum_partial");
+	ASSERT_EQ(skel->bss->final_csum_none, true, "final_csum_none");
+	ASSERT_EQ(skel->bss->broken_csum_start, false, "broken_csum_start");
+
+fail:
+	if (nstoken)
+		close_netns(nstoken);
+	system("ip netns del " NS_TEST " >& /dev/null");
+	decap_sanity__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/bpf_tracing_net.h b/tools/testing/selftests/bpf/progs/bpf_tracing_net.h
index b394817126cf..cfed4df490f3 100644
--- a/tools/testing/selftests/bpf/progs/bpf_tracing_net.h
+++ b/tools/testing/selftests/bpf/progs/bpf_tracing_net.h
@@ -50,6 +50,12 @@ 
 #define ICSK_TIME_LOSS_PROBE	5
 #define ICSK_TIME_REO_TIMEOUT	6
 
+#define ETH_HLEN		14
+#define ETH_P_IPV6		0x86DD
+
+#define CHECKSUM_NONE		0
+#define CHECKSUM_PARTIAL	3
+
 #define IFNAMSIZ		16
 
 #define RTF_GATEWAY		0x0002
diff --git a/tools/testing/selftests/bpf/progs/decap_sanity.c b/tools/testing/selftests/bpf/progs/decap_sanity.c
new file mode 100644
index 000000000000..b85113554cbf
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/decap_sanity.c
@@ -0,0 +1,68 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include "bpf_tracing_net.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+
+#define UDP_TEST_PORT 7777
+
+void *bpf_cast_to_kern_ctx(void *) __ksym;
+bool init_csum_partial = false;
+bool final_csum_none = false;
+bool broken_csum_start = false;
+
+static inline unsigned int skb_headlen(const struct sk_buff *skb)
+{
+	return skb->len - skb->data_len;
+}
+
+static unsigned int skb_headroom(const struct sk_buff *skb)
+{
+	return skb->data - skb->head;
+}
+
+static int skb_checksum_start_offset(const struct sk_buff *skb)
+{
+	return skb->csum_start - skb_headroom(skb);
+}
+
+SEC("tc")
+int decap_sanity(struct __sk_buff *skb)
+{
+	struct sk_buff *kskb;
+	struct ipv6hdr ip6h;
+	struct udphdr udph;
+	int err;
+
+	if (skb->protocol != __bpf_constant_htons(ETH_P_IPV6))
+		return TC_ACT_SHOT;
+
+	if (bpf_skb_load_bytes(skb, ETH_HLEN, &ip6h, sizeof(ip6h)))
+		return TC_ACT_SHOT;
+
+	if (ip6h.nexthdr != IPPROTO_UDP)
+		return TC_ACT_SHOT;
+
+	if (bpf_skb_load_bytes(skb, ETH_HLEN + sizeof(ip6h), &udph, sizeof(udph)))
+		return TC_ACT_SHOT;
+
+	if (udph.dest != __bpf_constant_htons(UDP_TEST_PORT))
+		return TC_ACT_SHOT;
+
+	kskb = bpf_cast_to_kern_ctx(skb);
+	init_csum_partial = (kskb->ip_summed == CHECKSUM_PARTIAL);
+	err = bpf_skb_adjust_room(skb, -(s32)(ETH_HLEN + sizeof(ip6h) + sizeof(udph)),
+				  1, BPF_F_ADJ_ROOM_FIXED_GSO);
+	if (err)
+		return TC_ACT_SHOT;
+	final_csum_none = (kskb->ip_summed == CHECKSUM_NONE);
+	if (kskb->ip_summed == CHECKSUM_PARTIAL &&
+	    (unsigned int)skb_checksum_start_offset(kskb) >= skb_headlen(kskb))
+		broken_csum_start = true;
+
+	return TC_ACT_SHOT;
+}
+
+char __license[] SEC("license") = "GPL";