Hi Martin,

On Wed, Nov 30, 2022 at 8:15 PM Martin KaFai Lau martin.lau@linux.dev wrote:

On 11/29/22 5:20 AM, Eyal Birger wrote:

...

diff --git a/net/xfrm/xfrm_interface_bpf.c b/net/xfrm/xfrm_interface_bpf.c new file mode 100644 index 000000000000..757e15857dbf --- /dev/null +++ b/net/xfrm/xfrm_interface_bpf.c @@ -0,0 +1,100 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Unstable XFRM Helpers for TC-BPF hook

• • These are called from SCHED_CLS BPF programs. Note that it is
• • allowed to break compatibility for these functions since the interface they
• • are exposed through to BPF programs is explicitly unstable.
• */

+#include <linux/bpf.h> +#include <linux/btf_ids.h>

+#include <net/dst_metadata.h> +#include <net/xfrm.h>

+struct bpf_xfrm_info {

No need to introduce a bpf variant of the "struct xfrm_md_info" (more on this later).

...

• u32 if_id;
  

• int link;
  

+};

+static struct metadata_dst __percpu *xfrm_md_dst; +__diag_push(); +__diag_ignore_all("-Wmissing-prototypes",

•           "Global functions as their definitions will be in xfrm_interface BTF");
  

+__used noinline +int bpf_skb_get_xfrm_info(struct __sk_buff *skb_ctx, struct bpf_xfrm_info *to)

This kfunc is not needed. It only reads the skb->_skb_refdst. The new kfunc bpf_rdonly_cast() can be used. Take a look at the bpf_rdonly_cast() usages in the selftests/bpf/progs/type_cast.c. It was in bpf-next only but should also be in net-next now.

I'm somewhat concerned with this approach. Indeed it would remove the kfunc, and the API is declared "unstable", but still the implementation as dst isn't relevant to the user and would make the programs less readable.

Also note that the helper can be also used as it is to get the xfrm info at egress from an lwt route (which stores the xfrm_info in the dst lwstate).

...

+{

• struct sk_buff *skb = (struct sk_buff *)skb_ctx;
  

• struct xfrm_md_info *info;
  

• memset(to, 0, sizeof(*to));
  

• info = skb_xfrm_md_info(skb);
  

• if (!info)
  

•         return -EINVAL;
  

• to->if_id = info->if_id;
  

• to->link = info->link;
  

• return 0;
  

+}

+__used noinline +int bpf_skb_set_xfrm_info(struct __sk_buff *skb_ctx,

•                   const struct bpf_xfrm_info *from)
  

Directly use "const struct xfrm_md_info *from" instead. This kfunc can check from->dst_orig != NULL and return -EINVAL. It will then have a consistent API with the bpf_rdonly_cast() mentioned above.

See above.

...

+{

• struct sk_buff *skb = (struct sk_buff *)skb_ctx;
  

• struct metadata_dst *md_dst;
  

• struct xfrm_md_info *info;
  

• if (unlikely(skb_metadata_dst(skb)))
  

•         return -EINVAL;
  

• md_dst = this_cpu_ptr(xfrm_md_dst);
  

• info = &md_dst->u.xfrm_info;
  

• memset(info, 0, sizeof(*info));
  

Unnecessary memset here. Everything should have been initialized below. bpf_skb_set_tunnel_key() needs memset but not here.

Ok.

...

• info->if_id = from->if_id;
  

• info->link = from->link;
  

• skb_dst_force(skb);
  

• info->dst_orig = skb_dst(skb);
  

• dst_hold((struct dst_entry *)md_dst);
  

• skb_dst_set(skb, (struct dst_entry *)md_dst);
  

• return 0;
  

+}

+__diag_pop()

+BTF_SET8_START(xfrm_ifc_kfunc_set) +BTF_ID_FLAGS(func, bpf_skb_get_xfrm_info) +BTF_ID_FLAGS(func, bpf_skb_set_xfrm_info) +BTF_SET8_END(xfrm_ifc_kfunc_set)

+static const struct btf_kfunc_id_set xfrm_interface_kfunc_set = {

• .owner = THIS_MODULE,
  

• .set   = &xfrm_ifc_kfunc_set,
  

+};

+int __init register_xfrm_interface_bpf(void) +{

• int err;
  

• xfrm_md_dst = metadata_dst_alloc_percpu(0, METADATA_XFRM,
  

•                                         GFP_KERNEL);
  

May be DEFINE_PER_CPU() instead?

Are you suggesting duplicating the dst init/cleanup logic here? Personally given that this happens once at module load, I think it's best to use the existing infrastructure, but am willing to add this here if you think it's better.

Thanks for the review! Eyal.

On 12/1/22 5:30 AM, Eyal Birger wrote:

Hi Martin,

On Thu, Dec 1, 2022 at 7:55 AM Eyal Birger eyal.birger@gmail.com wrote:

...

Hi Martin,

On Wed, Nov 30, 2022 at 8:15 PM Martin KaFai Lau martin.lau@linux.dev wrote:

...

On 11/29/22 5:20 AM, Eyal Birger wrote:

...

diff --git a/net/xfrm/xfrm_interface_bpf.c b/net/xfrm/xfrm_interface_bpf.c new file mode 100644 index 000000000000..757e15857dbf --- /dev/null +++ b/net/xfrm/xfrm_interface_bpf.c @@ -0,0 +1,100 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Unstable XFRM Helpers for TC-BPF hook

• • These are called from SCHED_CLS BPF programs. Note that it is
• • allowed to break compatibility for these functions since the interface they
• • are exposed through to BPF programs is explicitly unstable.
• */

+#include <linux/bpf.h> +#include <linux/btf_ids.h>

+#include <net/dst_metadata.h> +#include <net/xfrm.h>

+struct bpf_xfrm_info {

No need to introduce a bpf variant of the "struct xfrm_md_info" (more on this later).

...

• u32 if_id;
  

• int link;
  

+};

+static struct metadata_dst __percpu *xfrm_md_dst; +__diag_push(); +__diag_ignore_all("-Wmissing-prototypes",

•           "Global functions as their definitions will be in xfrm_interface BTF");
  

+__used noinline +int bpf_skb_get_xfrm_info(struct __sk_buff *skb_ctx, struct bpf_xfrm_info *to)

This kfunc is not needed. It only reads the skb->_skb_refdst. The new kfunc bpf_rdonly_cast() can be used. Take a look at the bpf_rdonly_cast() usages in the selftests/bpf/progs/type_cast.c. It was in bpf-next only but should also be in net-next now.

I'm somewhat concerned with this approach. Indeed it would remove the kfunc, and the API is declared "unstable", but still the implementation as dst isn't relevant to the user and would make the programs less readable.

Also note that the helper can be also used as it is to get the xfrm info at egress from an lwt route (which stores the xfrm_info in the dst lwstate).

Right, the whole skb_xfrm_md_info() can be implemented in bpf prog itself, like checking lwtstate.

If adding a kfunc, how about directly expose skb_xfrm_md_info() itself as a kfunc to bpf prog and directly return a "struct xfrm_md_info *" instead. Then there is no need to copy if_id/link...etc. The bpf prog has no need to initialize the "to" also. Something like this:

__used noinline const struct xfrm_md_info *bpf_skb_xfrm_md_info(const struct __sk_buff *skb) { ... }

BTF_ID_FLAGS(func, bpf_skb_xfrm_md_info, KF_RET_NULL)

...

...

...

+{

• struct sk_buff *skb = (struct sk_buff *)skb_ctx;
  

• struct xfrm_md_info *info;
  

• memset(to, 0, sizeof(*to));
  

• info = skb_xfrm_md_info(skb);
  

• if (!info)
  

•         return -EINVAL;
  

• to->if_id = info->if_id;
  

• to->link = info->link;
  

• return 0;
  

+}

+__used noinline +int bpf_skb_set_xfrm_info(struct __sk_buff *skb_ctx,

•                   const struct bpf_xfrm_info *from)
  

Directly use "const struct xfrm_md_info *from" instead. This kfunc can check from->dst_orig != NULL and return -EINVAL. It will then have a consistent API with the bpf_rdonly_cast() mentioned above.

See above.

Also, when trying this approach with bpf_set_xfrm_info() accepting "const struct xfrm_md_info *from" I fail to load the program:

libbpf: prog 'set_xfrm_info': BPF program load failed: Invalid argument libbpf: prog 'set_xfrm_info': -- BEGIN PROG LOAD LOG -- 0: R1=ctx(off=0,imm=0) R10=fp0 ; int set_xfrm_info(struct __sk_buff *skb) 0: (bf) r6 = r1 ; R1=ctx(off=0,imm=0) R6_w=ctx(off=0,imm=0) 1: (b7) r1 = 0 ; R1_w=0 ; struct xfrm_md_info info = {}; 2: (7b) *(u64 *)(r10 -8) = r1 ; R1_w=0 R10=fp0 fp-8_w=00000000 3: (7b) *(u64 *)(r10 -16) = r1 ; R1_w=0 R10=fp0 fp-16_w=00000000 4: (b4) w1 = 0 ; R1_w=0 ; __u32 index = 0; 5: (63) *(u32 *)(r10 -20) = r1 ; R1_w=0 R10=fp0 fp-24=0000???? 6: (bf) r2 = r10 ; R2_w=fp0 R10=fp0 ; 7: (07) r2 += -20 ; R2_w=fp-20 ; if_id = bpf_map_lookup_elem(&dst_if_id_map, &index); 8: (18) r1 = 0xffff888006751c00 ; R1_w=map_ptr(off=0,ks=4,vs=4,imm=0) 10: (85) call bpf_map_lookup_elem#1 ; R0_w=map_value_or_null(id=1,off=0,ks=4,vs=4,imm=0) 11: (bf) r1 = r0 ; R0_w=map_value_or_null(id=1,off=0,ks=4,vs=4,imm=0) R1_w=map_value_or_null(id=1,off=0,ks=4,vs=4,imm=0) 12: (b4) w0 = 2 ; R0_w=2 ; if (!if_id) 13: (15) if r1 == 0x0 goto pc+10 ; R1_w=map_value(off=0,ks=4,vs=4,imm=0) 14: (bf) r2 = r10 ; R2_w=fp0 R10=fp0 ; 15: (07) r2 += -16 ; R2_w=fp-16 ; info.if_id = *if_id; 16: (61) r1 = *(u32 *)(r1 +0) ; R1_w=scalar(umax=4294967295,var_off=(0x0; 0xffffffff)) ; info.if_id = *if_id; 17: (63) *(u32 *)(r2 +0) = r1 ; R1_w=scalar(umax=4294967295,var_off=(0x0; 0xffffffff)) R2_w=fp-16 fp-16_w= ; ret = bpf_skb_set_xfrm_info(skb, &info); 18: (bf) r1 = r6 ; R1_w=ctx(off=0,imm=0) R6_w=ctx(off=0,imm=0) 19: (85) call bpf_skb_set_xfrm_info#81442 arg#1 pointer type STRUCT xfrm_md_info must point to scalar, or struct with scalar

Is there some registration I need to do for this struct?

Ah, thanks for trying! hmm... it will need a change to the verifier. likely tag the param with something like "const struct xfrm_md_info *from__nonscalar_ok".

The reason of my earlier suggestion was to avoid the need to duplicate future changes in xfrm_md_info to bpf_xfrm_info and more importantly avoid creating another __sk_buff vs sk_buff like usage confusion.

For now, lets stay with bpf_xfrm_info. This can be changed later.

On 11/29/22 5:20 AM, Eyal Birger wrote:

Test the xfrm_info kfunc helpers.

Note: the tests require support for xfrmi "external" mode in iproute2.

The test setup creates three name spaces - NS0, NS1, NS2.

XFRM tunnels are setup between NS0 and the two other NSs.

The kfunc helpers are used to steer traffic from NS0 to the other NSs based on a userspace populated map and validate that the return traffic had arrived from the desired NS.

Signed-off-by: Eyal Birger eyal.birger@gmail.com

---

v2:

• use an lwt route in NS1 for testing that flow as well
• indendation fix

---

tools/testing/selftests/bpf/config | 2 + .../selftests/bpf/prog_tests/test_xfrm_info.c | 343 ++++++++++++++++++ .../selftests/bpf/progs/test_xfrm_info_kern.c | 74 ++++ 3 files changed, 419 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/test_xfrm_info.c create mode 100644 tools/testing/selftests/bpf/progs/test_xfrm_info_kern.c

diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config index 9213565c0311..9f39943d6ebd 100644 --- a/tools/testing/selftests/bpf/config +++ b/tools/testing/selftests/bpf/config @@ -20,6 +20,7 @@ CONFIG_IKCONFIG_PROC=y CONFIG_IMA=y CONFIG_IMA_READ_POLICY=y CONFIG_IMA_WRITE_POLICY=y +CONFIG_INET_ESP=y CONFIG_IP_NF_FILTER=y CONFIG_IP_NF_RAW=y CONFIG_IP_NF_TARGET_SYNPROXY=y @@ -71,3 +72,4 @@ CONFIG_TEST_BPF=y CONFIG_USERFAULTFD=y CONFIG_VXLAN=y CONFIG_XDP_SOCKETS=y +CONFIG_XFRM_INTERFACE=y diff --git a/tools/testing/selftests/bpf/prog_tests/test_xfrm_info.c b/tools/testing/selftests/bpf/prog_tests/test_xfrm_info.c new file mode 100644 index 000000000000..3aef72540934 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/test_xfrm_info.c

Nit. Just xfrm_info.c

@@ -0,0 +1,343 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause

+/*

• • Topology:

• • ---

• • NS0 namespace | NS1 namespace | NS2 namespace

• •                     |                        |
    

• • +---------------+ | +---------------+ |
• • | ipsec0 |---------| ipsec0 | |
• • | 192.168.1.100 | | | 192.168.1.200 | |
• • | if_id: bpf | | +---------------+ |
• • +---------------+ | |

• •       |             |                        |   +---------------+
    

• •       |             |                        |   |    ipsec0     |
    

• •       \------------------------------------------| 192.168.1.200 |
    

• •                     |                        |   +---------------+
    

• •                     |                        |
    

• •                     |                        | (overlay network)
    

• •  ------------------------------------------------------
    

• •                     |                        | (underlay network)
    

• • +--------------+ | +--------------+ |
• • | veth01 |----------| veth10 | |
• • | 172.16.1.100 | | | 172.16.1.200 | |
• • ---------------+ | +--------------+ |

• •                     |                        |
    

• • +--------------+ | | +--------------+
• • | veth02 |-----------------------------------| veth20 |
• • | 172.16.2.100 | | | | 172.16.2.200 |
• • +--------------+ | | +--------------+
• • Test Packet flow

• • ---

• • The tests perform 'ping 192.168.1.200' from the NS0 namespace:
• • 1. request is routed to NS0 ipsec0
• • 2. NS0 ipsec0 tc egress BPF program is triggered and sets the if_id based

• • on a map value. This makes the ipsec0 device in external mode select the
    

• • destination tunnel
    

• • 3. ping reaches the other namespace (NS1 or NS2 based on which if_id was

• • used) and response is sent
    

• • 4. response is received on NS0 ipsec0, tc ingress program is triggered and

• • records the response if_id in the map
    

• • 5. requested if_id is compared with received if_id
• */

+#include <net/if.h>

+#include "test_progs.h" +#include "network_helpers.h" +#include "test_xfrm_info_kern.skel.h"

+#define NS0 "xfrm_test_ns0" +#define NS1 "xfrm_test_ns1" +#define NS2 "xfrm_test_ns2"

+#define IF_ID_0_TO_1 1 +#define IF_ID_0_TO_2 2 +#define IF_ID_1 3 +#define IF_ID_2 4

+#define IP4_ADDR_VETH01 "172.16.1.100" +#define IP4_ADDR_VETH10 "172.16.1.200" +#define IP4_ADDR_VETH02 "172.16.2.100" +#define IP4_ADDR_VETH20 "172.16.2.200"

+#define ESP_DUMMY_PARAMS \

• "proto esp aead 'rfc4106(gcm(aes))' " \
• "0xe4d8f4b4da1df18a3510b3781496daa82488b713 128 mode tunnel "

+#define PING_ARGS "-i 0.01 -c 3 -w 10 -q"

+#define SYS(fmt, ...) \

• ({ \

• char cmd[1024];					\
  

• snprintf(cmd, sizeof(cmd), fmt, ##__VA_ARGS__);	\
  

• if (!ASSERT_OK(system(cmd), cmd))		\
  

• 	goto fail;				\
  

• })

+#define SYS_NOFAIL(fmt, ...) \

• ({ \

• char cmd[1024];					\
  

• snprintf(cmd, sizeof(cmd), fmt, ##__VA_ARGS__);	\
  

• system(cmd);					\
  

• })

+static int attach_tc_prog(struct bpf_tc_hook *hook, int igr_fd, int egr_fd) +{

• DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts1, .handle = 1,

• 	    .priority = 1, .prog_fd = igr_fd);
  

• DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts2, .handle = 1,

• 	    .priority = 1, .prog_fd = egr_fd);
  

• int ret;
• ret = bpf_tc_hook_create(hook);
• if (!ASSERT_OK(ret, "create tc hook"))

• return ret;
  

• if (igr_fd >= 0) {

• hook->attach_point = BPF_TC_INGRESS;
  

• ret = bpf_tc_attach(hook, &opts1);
  

• if (!ASSERT_OK(ret, "bpf_tc_attach")) {
  

• 	bpf_tc_hook_destroy(hook);
  

• 	return ret;
  

• }
  

• }
• if (egr_fd >= 0) {

• hook->attach_point = BPF_TC_EGRESS;
  

• ret = bpf_tc_attach(hook, &opts2);
  

• if (!ASSERT_OK(ret, "bpf_tc_attach")) {
  

• 	bpf_tc_hook_destroy(hook);
  

• 	return ret;
  

• }
  

• }
• return 0;

+}

+static void cleanup(void) +{

• SYS_NOFAIL("test -f /var/run/netns/" NS0 " && ip netns delete " NS0);
• SYS_NOFAIL("test -f /var/run/netns/" NS1 " && ip netns delete " NS1);
• SYS_NOFAIL("test -f /var/run/netns/" NS2 " && ip netns delete " NS2);

+}

+static int config_underlay(void) +{

• SYS("ip netns add " NS0);
• SYS("ip netns add " NS1);
• SYS("ip netns add " NS2);
• /* NS0 <-> NS1 [veth01 <-> veth10] */
• SYS("ip link add veth01 netns " NS0 " type veth peer name veth10 netns " NS1);
• SYS("ip -net " NS0 " addr add " IP4_ADDR_VETH01 "/24 dev veth01");
• SYS("ip -net " NS0 " link set dev veth01 up");
• SYS("ip -net " NS1 " addr add " IP4_ADDR_VETH10 "/24 dev veth10");
• SYS("ip -net " NS1 " link set dev veth10 up");
• /* NS0 <-> NS2 [veth02 <-> veth20] */
• SYS("ip link add veth02 netns " NS0 " type veth peer name veth20 netns " NS2);
• SYS("ip -net " NS0 " addr add " IP4_ADDR_VETH02 "/24 dev veth02");
• SYS("ip -net " NS0 " link set dev veth02 up");
• SYS("ip -net " NS2 " addr add " IP4_ADDR_VETH20 "/24 dev veth20");
• SYS("ip -net " NS2 " link set dev veth20 up");
• return 0;

+fail:

• return -1;

+}

+static int setup_xfrm_tunnel_ns(const char *ns, const char *ipv4_local,

• 		const char *ipv4_remote, int if_id)
  

+{

• /* State: local -> remote */
• SYS("ip -net %s xfrm state add src %s dst %s spi 1 "

•    ESP_DUMMY_PARAMS "if_id %d", ns, ipv4_local, ipv4_remote, if_id);
  

• /* State: local <- remote */
• SYS("ip -net %s xfrm state add src %s dst %s spi 1 "

•    ESP_DUMMY_PARAMS "if_id %d", ns, ipv4_remote, ipv4_local, if_id);
  

• /* Policy: local -> remote */
• SYS("ip -net %s xfrm policy add dir out src 0.0.0.0/0 dst 0.0.0.0/0 "

•    "if_id %d tmpl src %s dst %s proto esp mode tunnel if_id %d", ns,
  

•    if_id, ipv4_local, ipv4_remote, if_id);
  

• /* Policy: local <- remote */
• SYS("ip -net %s xfrm policy add dir in src 0.0.0.0/0 dst 0.0.0.0/0 "

•    "if_id %d tmpl src %s dst %s proto esp mode tunnel if_id %d", ns,
  

•    if_id, ipv4_remote, ipv4_local, if_id);
  

• return 0;

+fail:

• return -1;

+}

+static int setup_xfrm_tunnel(const char *ns_a, const char *ns_b,

• 	     const char *ipv4_a, const char *ipv4_b,
  

• 	     int if_id_a, int if_id_b)
  

+{

• return setup_xfrm_tunnel_ns(ns_a, ipv4_a, ipv4_b, if_id_a) ||

• setup_xfrm_tunnel_ns(ns_b, ipv4_b, ipv4_a, if_id_b);
  

+}

+static int config_overlay(void) +{

• if (setup_xfrm_tunnel(NS0, NS1, IP4_ADDR_VETH01, IP4_ADDR_VETH10,

• 	      IF_ID_0_TO_1, IF_ID_1))
  

• goto fail;
  

• if (setup_xfrm_tunnel(NS0, NS2, IP4_ADDR_VETH02, IP4_ADDR_VETH20,

• 	      IF_ID_0_TO_2, IF_ID_2))
  

• goto fail;
  

• SYS("ip -net " NS0 " link add ipsec0 type xfrm external");
• SYS("ip -net " NS0 " addr add 192.168.1.100/24 dev ipsec0");
• SYS("ip -net " NS0 " link set dev ipsec0 up");
• SYS("ip -net " NS1 " link add ipsec0 type xfrm external");
• SYS("ip -net " NS1 " addr add 192.168.1.200/32 dev ipsec0");
• SYS("ip -net " NS1 " link set dev ipsec0 up");
• SYS("ip -net " NS1 " route add 192.168.1.100/32 dev ipsec0 encap xfrm if_id %d", IF_ID_1);
• SYS("ip -net " NS2 " link add ipsec0 type xfrm if_id %d", IF_ID_2);
• SYS("ip -net " NS2 " addr add 192.168.1.200/24 dev ipsec0");
• SYS("ip -net " NS2 " link set dev ipsec0 up");
• return 0;

+fail:

• return -1;

+}

+static int test_ping(int family, const char *addr) +{

• SYS("%s %s %s > /dev/null", ping_command(family), PING_ARGS, addr);
• return 0;

+fail:

• return -1;

+}

+static int test_xfrm_ping(int dst_if_id_map_fd, u32 if_id) +{

• u32 dst_if_id;
• int key, err;
• key = 0;
• dst_if_id = if_id;
• err = bpf_map_update_elem(dst_if_id_map_fd, &key, &dst_if_id, BPF_ANY);
• if (!ASSERT_OK(err, "update bpf dst_if_id_map"))

• return -1;
  

• if (test_ping(AF_INET, "192.168.1.200"))

• return -1;
  

• key = 1;
• dst_if_id = 0;
• err = bpf_map_lookup_elem(dst_if_id_map_fd, &key, &dst_if_id);
• if (!ASSERT_OK(err, "lookup bpf dst_if_id_map"))

• return -1;
  

• if (!ASSERT_EQ(dst_if_id, if_id, "if_id"))

• return -1;
  

• return 0;

+}

+static void test_xfrm_info(void) +{

• int get_xfrm_info_prog_fd, set_xfrm_info_prog_fd;
• struct test_xfrm_info_kern *skel = NULL;
• struct nstoken *nstoken = NULL;
• int dst_if_id_map_fd = -1;
• int ifindex = -1;
• DECLARE_LIBBPF_OPTS(bpf_tc_hook, tc_hook,

• 	    .attach_point = BPF_TC_INGRESS);
  

• /* load and attach bpf progs to ipsec dev tc hook point */
• skel = test_xfrm_info_kern__open_and_load();
• if (!ASSERT_OK_PTR(skel, "test_xfrm_info_kern__open_and_load"))

• goto done;
  

• nstoken = open_netns(NS0);
• ifindex = if_nametoindex("ipsec0");
• if (!ASSERT_NEQ(ifindex, 0, "ipsec0 ifindex"))

• goto done;
  

• tc_hook.ifindex = ifindex;
• set_xfrm_info_prog_fd = bpf_program__fd(skel->progs.set_xfrm_info);
• get_xfrm_info_prog_fd = bpf_program__fd(skel->progs.get_xfrm_info);
• if (!ASSERT_GE(set_xfrm_info_prog_fd, 0, "bpf_program__fd"))

• goto done;
  

• if (!ASSERT_GE(get_xfrm_info_prog_fd, 0, "bpf_program__fd"))

• goto done;
  

• if (attach_tc_prog(&tc_hook, get_xfrm_info_prog_fd,

• 	   set_xfrm_info_prog_fd))
  

• goto done;
  

• dst_if_id_map_fd = bpf_map__fd(skel->maps.dst_if_id_map);
• if (!ASSERT_GE(dst_if_id_map_fd, 0, "bpf_map__fd"))

• goto done;
  

• if (!ASSERT_EQ(test_xfrm_ping(dst_if_id_map_fd, IF_ID_0_TO_1), 0,

•        "ping " NS1))
  

• goto done;
  

• if (!ASSERT_EQ(test_xfrm_ping(dst_if_id_map_fd, IF_ID_0_TO_2), 0,

•        "ping " NS2))
  

• goto done;
  

+done:

• if (nstoken)

• close_netns(nstoken);
  

• if (dst_if_id_map_fd >= 0)

• close(dst_if_id_map_fd);
  

• if (skel)

• test_xfrm_info_kern__destroy(skel);
  

+}

+#define RUN_TEST(name) \

• ({ \

• if (test__start_subtest(#name)) {			\
  

• 	test_ ## name();				\
  

• }							\
  

• })

+static void *test_xfrm_info_run_tests(void *arg) +{

• cleanup();
• config_underlay();
• config_overlay();

config_*() is returning ok/err but no error checking here. Does it make sense to continue if the config_*() failed?

• RUN_TEST(xfrm_info);

nit. Remove this macro indirection. There is only one test.

• cleanup();
• return NULL;

+}

+static int probe_iproute2(void) +{

• if (SYS_NOFAIL("ip link add type xfrm help 2>&1 | "

•        "grep external > /dev/null")) {
  

• fprintf(stdout, "%s:SKIP: iproute2 with xfrm external support needed for this test\n", __func__);
  

Unfortunately, the BPF CI iproute2 does not have this support also :( I am worry it will just stay SKIP for some time and rot. Can you try to directly use netlink here?

https://github.com/kernel-patches/bpf/actions/runs/3578467213/jobs/601937075...

• return -1;
  

• }
• return 0;

+}

+void serial_test_xfrm_info(void)

Remove "serial_". New test must be able to run in parallel ("./test_progs -j").

+{

• pthread_t test_thread;
• int err;
• if (probe_iproute2()) {

• test__skip();
  

• return;
  

• }
• /* Run the tests in their own thread to isolate the namespace changes

• * so they do not affect the environment of other tests.
  

• * (specifically needed because of unshare(CLONE_NEWNS) in open_netns())
  

• */
  

I think this comment is mostly inherited from other tests (eg. tc_redirect.c) but the pthread dance is actually unnecessary. The test_progs.c will restore the original netns before running the next test. I am abort to remove this from the tc_redirect.c also. Please also avoid this pthread create here.

• err = pthread_create(&test_thread, NULL, &test_xfrm_info_run_tests, NULL);
• if (ASSERT_OK(err, "pthread_create"))

• ASSERT_OK(pthread_join(test_thread, NULL), "pthread_join");
  

+} diff --git a/tools/testing/selftests/bpf/progs/test_xfrm_info_kern.c b/tools/testing/selftests/bpf/progs/test_xfrm_info_kern.c new file mode 100644 index 000000000000..98991a83c1e9 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_xfrm_info_kern.c

Nit. Same here. Just xfrm_info.c.

@@ -0,0 +1,74 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/bpf.h> +#include <linux/pkt_cls.h> +#include <bpf/bpf_helpers.h>

+#define log_err(__ret) bpf_printk("ERROR line:%d ret:%d\n", __LINE__, __ret)

Please try not to use unnecessary bpf_printk(). BPF CI is not capturing it also.

+struct {

• __uint(type, BPF_MAP_TYPE_ARRAY);
• __uint(max_entries, 2);
• __type(key, __u32);
• __type(value, __u32);

+} dst_if_id_map SEC(".maps");

It is easier to use global variables instead of a map.

+struct bpf_xfrm_info {

• __u32 if_id;
• int link;

+};

This needs __attribute__((preserve_access_index) for CO-RE. It is easier to just include vmlinux.h to get the struct xfrm_md_info { ... }.

+int bpf_skb_set_xfrm_info(struct __sk_buff *skb_ctx,

• 	  const struct bpf_xfrm_info *from) __ksym;
  

+int bpf_skb_get_xfrm_info(struct __sk_buff *skb_ctx,

• 	  struct bpf_xfrm_info *to) __ksym;
  

+SEC("tc") +int set_xfrm_info(struct __sk_buff *skb) +{

• struct bpf_xfrm_info info = {};
• __u32 *if_id = NULL;
• __u32 index = 0;
• int ret = -1;
• if_id = bpf_map_lookup_elem(&dst_if_id_map, &index);
• if (!if_id) {

• log_err(ret);
  

• return TC_ACT_SHOT;
  

• }
• info.if_id = *if_id;
• ret = bpf_skb_set_xfrm_info(skb, &info);
• if (ret < 0) {

• log_err(ret);
  

• return TC_ACT_SHOT;
  

• }
• return TC_ACT_UNSPEC;

+}

+SEC("tc") +int get_xfrm_info(struct __sk_buff *skb) +{

• struct bpf_xfrm_info info = {};
• __u32 *if_id = NULL;
• __u32 index = 1;
• int ret = -1;
• if_id = bpf_map_lookup_elem(&dst_if_id_map, &index);
• if (!if_id) {

• log_err(ret);
  

• return TC_ACT_SHOT;
  

• }
• ret = bpf_skb_get_xfrm_info(skb, &info);
• if (ret < 0) {

• log_err(ret);
  

• return TC_ACT_SHOT;
  

• }
• *if_id = info.if_id;
• return TC_ACT_UNSPEC;

+}

+char _license[] SEC("license") = "GPL";

Hi Martin,

On Wed, Nov 30, 2022 at 8:41 PM Martin KaFai Lau martin.lau@linux.dev wrote:

On 11/29/22 5:20 AM, Eyal Birger wrote:

...

Test the xfrm_info kfunc helpers.

Note: the tests require support for xfrmi "external" mode in iproute2.

The test setup creates three name spaces - NS0, NS1, NS2.

XFRM tunnels are setup between NS0 and the two other NSs.

The kfunc helpers are used to steer traffic from NS0 to the other NSs based on a userspace populated map and validate that the return traffic had arrived from the desired NS.

Signed-off-by: Eyal Birger eyal.birger@gmail.com

---

v2:

• use an lwt route in NS1 for testing that flow as well
• indendation fix

---

tools/testing/selftests/bpf/config | 2 + .../selftests/bpf/prog_tests/test_xfrm_info.c | 343 ++++++++++++++++++ .../selftests/bpf/progs/test_xfrm_info_kern.c | 74 ++++ 3 files changed, 419 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/test_xfrm_info.c create mode 100644 tools/testing/selftests/bpf/progs/test_xfrm_info_kern.c

diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config index 9213565c0311..9f39943d6ebd 100644 --- a/tools/testing/selftests/bpf/config +++ b/tools/testing/selftests/bpf/config @@ -20,6 +20,7 @@ CONFIG_IKCONFIG_PROC=y CONFIG_IMA=y CONFIG_IMA_READ_POLICY=y CONFIG_IMA_WRITE_POLICY=y +CONFIG_INET_ESP=y CONFIG_IP_NF_FILTER=y CONFIG_IP_NF_RAW=y CONFIG_IP_NF_TARGET_SYNPROXY=y @@ -71,3 +72,4 @@ CONFIG_TEST_BPF=y CONFIG_USERFAULTFD=y CONFIG_VXLAN=y CONFIG_XDP_SOCKETS=y +CONFIG_XFRM_INTERFACE=y diff --git a/tools/testing/selftests/bpf/prog_tests/test_xfrm_info.c b/tools/testing/selftests/bpf/prog_tests/test_xfrm_info.c new file mode 100644 index 000000000000..3aef72540934 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/test_xfrm_info.c

Nit. Just xfrm_info.c

Ok.

...

@@ -0,0 +1,343 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause

+/*

• • Topology:

• • ---

• • NS0 namespace | NS1 namespace | NS2 namespace

• •                     |                        |
    

• • +---------------+ | +---------------+ |
• • | ipsec0 |---------| ipsec0 | |
• • | 192.168.1.100 | | | 192.168.1.200 | |
• • | if_id: bpf | | +---------------+ |
• • +---------------+ | |

• •       |             |                        |   +---------------+
    

• •       |             |                        |   |    ipsec0     |
    

• •       \------------------------------------------| 192.168.1.200 |
    

• •                     |                        |   +---------------+
    

• •                     |                        |
    

• •                     |                        | (overlay network)
    

• •  ------------------------------------------------------
    

• •                     |                        | (underlay network)
    

• • +--------------+ | +--------------+ |
• • | veth01 |----------| veth10 | |
• • | 172.16.1.100 | | | 172.16.1.200 | |
• • ---------------+ | +--------------+ |

• •                     |                        |
    

• • +--------------+ | | +--------------+
• • | veth02 |-----------------------------------| veth20 |
• • | 172.16.2.100 | | | | 172.16.2.200 |
• • +--------------+ | | +--------------+

[...]

...

+#define RUN_TEST(name) \

• ({                                                              \
  

•         if (test__start_subtest(#name)) {                       \
  

•                 test_ ## name();                                \
  

•         }                                                       \
  

• })
  

+static void *test_xfrm_info_run_tests(void *arg) +{

• cleanup();
  

• config_underlay();
  

• config_overlay();
  

config_*() is returning ok/err but no error checking here. Does it make sense to continue if the config_*() failed?

I'll assert their success.

...

• RUN_TEST(xfrm_info);
  

nit. Remove this macro indirection. There is only one test.

Ok. I was considering other possible tests in the future, but this can be added then.

...

• cleanup();
  

• return NULL;
  

+}

+static int probe_iproute2(void) +{

• if (SYS_NOFAIL("ip link add type xfrm help 2>&1 | "
  

•                "grep external > /dev/null")) {
  

•         fprintf(stdout, "%s:SKIP: iproute2 with xfrm external support needed for this test\n", __func__);
  

Unfortunately, the BPF CI iproute2 does not have this support also :( I am worry it will just stay SKIP for some time and rot. Can you try to directly use netlink here?

Yeah, I wasn't sure if adding a libmnl (or alternative) dependency was ok here, and also didn't want to copy all that nl logic here. So I figured it would get there eventually.

I noticed libmnl is used by the nf tests, so maybe its inclusion isn't too bad. Unless there's a better approach.

As you noted, I should add this for the "external" support. However, I don't think adding the LWT route directly using nl is a good idea here so I'll make the NS1 use a regular xfrmi.

https://github.com/kernel-patches/bpf/actions/runs/3578467213/jobs/601937075...

...

•         return -1;
  

• }
  

• return 0;
  

+}

+void serial_test_xfrm_info(void)

Remove "serial_". New test must be able to run in parallel ("./test_progs -j").

Ok.

...

+{

• pthread_t test_thread;
  

• int err;
  

• if (probe_iproute2()) {
  

•         test__skip();
  

•         return;
  

• }
  

• /* Run the tests in their own thread to isolate the namespace changes
  

•  * so they do not affect the environment of other tests.
  

•  * (specifically needed because of unshare(CLONE_NEWNS) in open_netns())
  

•  */
  

I think this comment is mostly inherited from other tests (eg. tc_redirect.c) but the pthread dance is actually unnecessary. The test_progs.c will restore the original netns before running the next test. I am abort to remove this from the tc_redirect.c also. Please also avoid this pthread create here.

Ok. Indeed was inherited.

...

• err = pthread_create(&test_thread, NULL, &test_xfrm_info_run_tests, NULL);
  

• if (ASSERT_OK(err, "pthread_create"))
  

•         ASSERT_OK(pthread_join(test_thread, NULL), "pthread_join");
  

+} diff --git a/tools/testing/selftests/bpf/progs/test_xfrm_info_kern.c b/tools/testing/selftests/bpf/progs/test_xfrm_info_kern.c new file mode 100644 index 000000000000..98991a83c1e9 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_xfrm_info_kern.c

Nit. Same here. Just xfrm_info.c.

Ok.

...

@@ -0,0 +1,74 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/bpf.h> +#include <linux/pkt_cls.h> +#include <bpf/bpf_helpers.h>

+#define log_err(__ret) bpf_printk("ERROR line:%d ret:%d\n", __LINE__, __ret)

Please try not to use unnecessary bpf_printk(). BPF CI is not capturing it also.

Ok.

...

+struct {

• __uint(type, BPF_MAP_TYPE_ARRAY);
  

• __uint(max_entries, 2);
  

• __type(key, __u32);
  

• __type(value, __u32);
  

+} dst_if_id_map SEC(".maps");

It is easier to use global variables instead of a map.

Would these be available for read/write from the test application (as the map is currently populated/read from userspace)?

...

+struct bpf_xfrm_info {

• __u32 if_id;
  

• int link;
  

+};

This needs __attribute__((preserve_access_index) for CO-RE. It is easier to just include vmlinux.h to get the struct xfrm_md_info { ... }.

Ok.

...

+int bpf_skb_set_xfrm_info(struct __sk_buff *skb_ctx,

•                   const struct bpf_xfrm_info *from) __ksym;
  

+int bpf_skb_get_xfrm_info(struct __sk_buff *skb_ctx,

•                   struct bpf_xfrm_info *to) __ksym;
  

+SEC("tc") +int set_xfrm_info(struct __sk_buff *skb) +{

• struct bpf_xfrm_info info = {};
  

• __u32 *if_id = NULL;
  

• __u32 index = 0;
  

• int ret = -1;
  

• if_id = bpf_map_lookup_elem(&dst_if_id_map, &index);
  

• if (!if_id) {
  

•         log_err(ret);
  

•         return TC_ACT_SHOT;
  

• }
  

• info.if_id = *if_id;
  

• ret = bpf_skb_set_xfrm_info(skb, &info);
  

• if (ret < 0) {
  

•         log_err(ret);
  

•         return TC_ACT_SHOT;
  

• }
  

• return TC_ACT_UNSPEC;
  

+}

+SEC("tc") +int get_xfrm_info(struct __sk_buff *skb) +{

• struct bpf_xfrm_info info = {};
  

• __u32 *if_id = NULL;
  

• __u32 index = 1;
  

• int ret = -1;
  

• if_id = bpf_map_lookup_elem(&dst_if_id_map, &index);
  

• if (!if_id) {
  

•         log_err(ret);
  

•         return TC_ACT_SHOT;
  

• }
  

• ret = bpf_skb_get_xfrm_info(skb, &info);
  

• if (ret < 0) {
  

•         log_err(ret);
  

•         return TC_ACT_SHOT;
  

• }
  

• *if_id = info.if_id;
  

• return TC_ACT_UNSPEC;
  

+}

+char _license[] SEC("license") = "GPL";

Thanks for the review! Eyal.