[PATCH bpf-next v10 6/6] selftests/bpf: Add selftests for raw syncookie helpers in TC mode

Maxim Mikityanskiy
2022-06-15T13:49:54Z

This commit extends selftests for the new BPF helpers
bpf_tcp_raw_{gen,check}_syncookie_ipv{4,6} to also test the TC BPF
functionality added in the previous commit.

Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
---
.../selftests/bpf/prog_tests/xdp_synproxy.c | 55 +++++--
.../selftests/bpf/progs/xdp_synproxy_kern.c | 142 +++++++++++++-----
tools/testing/selftests/bpf/xdp_synproxy.c | 96 +++++++++---
3 files changed, 224 insertions(+), 69 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_synproxy.c b/tools/testing/selftests/bpf/prog_tests/xdp_synproxy.c
index d9ee884c2a2b..fb77a123fe89 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_synproxy.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_synproxy.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: LGPL-2.1 OR BSD-2-Clause
/* Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. All rights reserved. */

+#define _GNU_SOURCE
#include <test_progs.h>
#include <network_helpers.h>
#include <ctype.h>
@@ -12,9 +13,11 @@
goto out; \
})

-#define SYS_OUT(cmd) ({ \
- FILE *f = popen((cmd), "r"); \
- if (!ASSERT_OK_PTR(f, (cmd))) \
+#define SYS_OUT(cmd, ...) ({ \
+ char buf[1024]; \
+ snprintf(buf, sizeof(buf), (cmd), ##__VA_ARGS__); \
+ FILE *f = popen(buf, "r"); \
+ if (!ASSERT_OK_PTR(f, buf)) \
goto out; \
f; \
})
@@ -57,9 +60,10 @@ static bool expect_str(char *buf, size_t size, const char *str, const char *name
return ok;
}

-void test_xdp_synproxy(void)
+static void test_synproxy(bool xdp)
{
int server_fd = -1, client_fd = -1, accept_fd = -1;
+ char *prog_id, *prog_id_end;
struct nstoken *ns = NULL;
FILE *ctrl_file = NULL;
char buf[CMD_OUT_BUF_SIZE];
@@ -76,8 +80,9 @@ void test_xdp_synproxy(void)
* checksums and drops packets.
*/
SYS("ethtool -K tmp0 tx off");
- /* Workaround required for veth. */
- SYS("ip link set tmp0 xdp object xdp_dummy.o section xdp 2> /dev/null");
+ if (xdp)
+ /* Workaround required for veth. */
+ SYS("ip link set tmp0 xdp object xdp_dummy.o section xdp 2> /dev/null");

ns = open_netns("synproxy");
if (!ASSERT_OK_PTR(ns, "setns"))
@@ -97,14 +102,34 @@ void test_xdp_synproxy(void)
SYS("iptables -t filter -A INPUT \
-i tmp1 -m state --state INVALID -j DROP");

- ctrl_file = SYS_OUT("./xdp_synproxy --iface tmp1 --ports 8080 --single \
- --mss4 1460 --mss6 1440 --wscale 7 --ttl 64");
+ ctrl_file = SYS_OUT("./xdp_synproxy --iface tmp1 --ports 8080 \
+ --single --mss4 1460 --mss6 1440 \
+ --wscale 7 --ttl 64%s", xdp ? "" : " --tc");
size = fread(buf, 1, sizeof(buf), ctrl_file);
pclose(ctrl_file);
if (!expect_str(buf, size, "Total SYNACKs generated: 0\n",
"initial SYNACKs"))
goto out;

+ if (!xdp) {
+ ctrl_file = SYS_OUT("tc filter show dev tmp1 ingress");
+ size = fread(buf, 1, sizeof(buf), ctrl_file);
+ pclose(ctrl_file);
+ prog_id = memmem(buf, size, " id ", 4);
+ if (!ASSERT_OK_PTR(prog_id, "find prog id"))
+ goto out;
+ prog_id += 4;
+ if (!ASSERT_LT(prog_id, buf + size, "find prog id begin"))
+ goto out;
+ prog_id_end = prog_id;
+ while (prog_id_end < buf + size && *prog_id_end >= '0' &&
+ *prog_id_end <= '9')
+ prog_id_end++;
+ if (!ASSERT_LT(prog_id_end, buf + size, "find prog id end"))
+ goto out;
+ *prog_id_end = '\0';
+ }
+
server_fd = start_server(AF_INET, SOCK_STREAM, "198.18.0.2", 8080, 0);
if (!ASSERT_GE(server_fd, 0, "start_server"))
goto out;
@@ -124,7 +149,11 @@ void test_xdp_synproxy(void)
if (!ASSERT_OK_PTR(ns, "setns"))
goto out;

- ctrl_file = SYS_OUT("./xdp_synproxy --iface tmp1 --single");
+ if (xdp)
+ ctrl_file = SYS_OUT("./xdp_synproxy --iface tmp1 --single");
+ else
+ ctrl_file = SYS_OUT("./xdp_synproxy --prog %s --single",
+ prog_id);
size = fread(buf, 1, sizeof(buf), ctrl_file);
pclose(ctrl_file);
if (!expect_str(buf, size, "Total SYNACKs generated: 1\n",
@@ -144,3 +173,11 @@ void test_xdp_synproxy(void)
system("ip link del tmp0");
system("ip netns del synproxy");
}
+
+void test_xdp_synproxy(void)
+{
+ if (test__start_subtest("xdp"))
+ test_synproxy(true);
+ if (test__start_subtest("tc"))
+ test_synproxy(false);
+}
diff --git a/tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c b/tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c
index 53b9865276a4..9fd62e94b5e6 100644
--- a/tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c
+++ b/tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c
@@ -7,6 +7,9 @@
#include <bpf/bpf_endian.h>
#include <asm/errno.h>

+#define TC_ACT_OK 0
+#define TC_ACT_SHOT 2
+
#define NSEC_PER_SEC 1000000000L

#define ETH_ALEN 6
@@ -80,6 +83,12 @@ extern struct nf_conn *bpf_xdp_ct_lookup(struct xdp_md *xdp_ctx,
struct bpf_ct_opts *opts,
__u32 len_opts) __ksym;

+extern struct nf_conn *bpf_skb_ct_lookup(struct __sk_buff *skb_ctx,
+ struct bpf_sock_tuple *bpf_tuple,
+ u32 len_tuple,
+ struct bpf_ct_opts *opts,
+ u32 len_opts) __ksym;
+
extern void bpf_ct_release(struct nf_conn *ct) __ksym;

static __always_inline void swap_eth_addr(__u8 *a, __u8 *b)
@@ -382,7 +391,7 @@ static __always_inline int tcp_dissect(void *data, void *data_end,
return XDP_TX;
}

-static __always_inline int tcp_lookup(struct xdp_md *ctx, struct header_pointers *hdr)
+static __always_inline int tcp_lookup(void *ctx, struct header_pointers *hdr, bool xdp)
{
struct bpf_ct_opts ct_lookup_opts = {
.netns_id = BPF_F_CURRENT_NETNS,
@@ -416,7 +425,10 @@ static __always_inline int tcp_lookup(struct xdp_md *ctx, struct header_pointers
*/
return XDP_ABORTED;
}
- ct = bpf_xdp_ct_lookup(ctx, &tup, tup_size, &ct_lookup_opts, sizeof(ct_lookup_opts));
+ if (xdp)
+ ct = bpf_xdp_ct_lookup(ctx, &tup, tup_size, &ct_lookup_opts, sizeof(ct_lookup_opts));
+ else
+ ct = bpf_skb_ct_lookup(ctx, &tup, tup_size, &ct_lookup_opts, sizeof(ct_lookup_opts));
if (ct) {
unsigned long status = ct->status;

@@ -529,8 +541,9 @@ static __always_inline void tcpv6_gen_synack(struct header_pointers *hdr,
}

static __always_inline int syncookie_handle_syn(struct header_pointers *hdr,
- struct xdp_md *ctx,
- void *data, void *data_end)
+ void *ctx,
+ void *data, void *data_end,
+ bool xdp)
{
__u32 old_pkt_size, new_pkt_size;
/* Unlike clang 10, clang 11 and 12 generate code that doesn't pass the
@@ -666,8 +679,13 @@ static __always_inline int syncookie_handle_syn(struct header_pointers *hdr,
/* Set the new packet size. */
old_pkt_size = data_end - data;
new_pkt_size = sizeof(*hdr->eth) + ip_len + hdr->tcp->doff * 4;
- if (bpf_xdp_adjust_tail(ctx, new_pkt_size - old_pkt_size))
- return XDP_ABORTED;
+ if (xdp) {
+ if (bpf_xdp_adjust_tail(ctx, new_pkt_size - old_pkt_size))
+ return XDP_ABORTED;
+ } else {
+ if (bpf_skb_change_tail(ctx, new_pkt_size, 0))
+ return XDP_ABORTED;
+ }

values_inc_synacks();

@@ -693,71 +711,123 @@ static __always_inline int syncookie_handle_ack(struct header_pointers *hdr)
return XDP_PASS;
}

-SEC("xdp")
-int syncookie_xdp(struct xdp_md *ctx)
+static __always_inline int syncookie_part1(void *ctx, void *data, void *data_end,
+ struct header_pointers *hdr, bool xdp)
{
- void *data_end = (void *)(long)ctx->data_end;
- void *data = (void *)(long)ctx->data;
- struct header_pointers hdr;
- __s64 value;
- int ret;
-
struct bpf_ct_opts ct_lookup_opts = {
.netns_id = BPF_F_CURRENT_NETNS,
.l4proto = IPPROTO_TCP,
};
+ int ret;

- ret = tcp_dissect(data, data_end, &hdr);
+ ret = tcp_dissect(data, data_end, hdr);
if (ret != XDP_TX)
return ret;

- ret = tcp_lookup(ctx, &hdr);
+ ret = tcp_lookup(ctx, hdr, xdp);
if (ret != XDP_TX)
return ret;

/* Packet is TCP and doesn't belong to an established connection. */

- if ((hdr.tcp->syn ^ hdr.tcp->ack) != 1)
+ if ((hdr->tcp->syn ^ hdr->tcp->ack) != 1)
return XDP_DROP;

- /* Grow the TCP header to TCP_MAXLEN to be able to pass any hdr.tcp_len
+ /* Grow the TCP header to TCP_MAXLEN to be able to pass any hdr->tcp_len
* to bpf_tcp_raw_gen_syncookie_ipv{4,6} and pass the verifier.
*/
- if (bpf_xdp_adjust_tail(ctx, TCP_MAXLEN - hdr.tcp_len))
- return XDP_ABORTED;
+ if (xdp) {
+ if (bpf_xdp_adjust_tail(ctx, TCP_MAXLEN - hdr->tcp_len))
+ return XDP_ABORTED;
+ } else {
+ /* Without volatile the verifier throws this error:
+ * R9 32-bit pointer arithmetic prohibited
+ */
+ volatile u64 old_len = data_end - data;

- data_end = (void *)(long)ctx->data_end;
- data = (void *)(long)ctx->data;
+ if (bpf_skb_change_tail(ctx, old_len + TCP_MAXLEN - hdr->tcp_len, 0))
+ return XDP_ABORTED;
+ }
+
+ return XDP_TX;
+}

- if (hdr.ipv4) {
- hdr.eth = data;
- hdr.ipv4 = (void *)hdr.eth + sizeof(*hdr.eth);
+static __always_inline int syncookie_part2(void *ctx, void *data, void *data_end,
+ struct header_pointers *hdr, bool xdp)
+{
+ if (hdr->ipv4) {
+ hdr->eth = data;
+ hdr->ipv4 = (void *)hdr->eth + sizeof(*hdr->eth);
/* IPV4_MAXLEN is needed when calculating checksum.
* At least sizeof(struct iphdr) is needed here to access ihl.
*/
- if ((void *)hdr.ipv4 + IPV4_MAXLEN > data_end)
+ if ((void *)hdr->ipv4 + IPV4_MAXLEN > data_end)
return XDP_ABORTED;
- hdr.tcp = (void *)hdr.ipv4 + hdr.ipv4->ihl * 4;
- } else if (hdr.ipv6) {
- hdr.eth = data;
- hdr.ipv6 = (void *)hdr.eth + sizeof(*hdr.eth);
- hdr.tcp = (void *)hdr.ipv6 + sizeof(*hdr.ipv6);
+ hdr->tcp = (void *)hdr->ipv4 + hdr->ipv4->ihl * 4;
+ } else if (hdr->ipv6) {
+ hdr->eth = data;
+ hdr->ipv6 = (void *)hdr->eth + sizeof(*hdr->eth);
+ hdr->tcp = (void *)hdr->ipv6 + sizeof(*hdr->ipv6);
} else {
return XDP_ABORTED;
}

- if ((void *)hdr.tcp + TCP_MAXLEN > data_end)
+ if ((void *)hdr->tcp + TCP_MAXLEN > data_end)
return XDP_ABORTED;

/* We run out of registers, tcp_len gets spilled to the stack, and the
* verifier forgets its min and max values checked above in tcp_dissect.
*/
- hdr.tcp_len = hdr.tcp->doff * 4;
- if (hdr.tcp_len < sizeof(*hdr.tcp))
+ hdr->tcp_len = hdr->tcp->doff * 4;
+ if (hdr->tcp_len < sizeof(*hdr->tcp))
return XDP_ABORTED;

- return hdr.tcp->syn ? syncookie_handle_syn(&hdr, ctx, data, data_end) :
- syncookie_handle_ack(&hdr);
+ return hdr->tcp->syn ? syncookie_handle_syn(hdr, ctx, data, data_end, xdp) :
+ syncookie_handle_ack(hdr);
+}
+
+SEC("xdp")
+int syncookie_xdp(struct xdp_md *ctx)
+{
+ void *data_end = (void *)(long)ctx->data_end;
+ void *data = (void *)(long)ctx->data;
+ struct header_pointers hdr;
+ int ret;
+
+ ret = syncookie_part1(ctx, data, data_end, &hdr, true);
+ if (ret != XDP_TX)
+ return ret;
+
+ data_end = (void *)(long)ctx->data_end;
+ data = (void *)(long)ctx->data;
+
+ return syncookie_part2(ctx, data, data_end, &hdr, true);
+}
+
+SEC("tc")
+int syncookie_tc(struct __sk_buff *skb)
+{
+ void *data_end = (void *)(long)skb->data_end;
+ void *data = (void *)(long)skb->data;
+ struct header_pointers hdr;
+ int ret;
+
+ ret = syncookie_part1(skb, data, data_end, &hdr, false);
+ if (ret != XDP_TX)
+ return ret == XDP_PASS ? TC_ACT_OK : TC_ACT_SHOT;
+
+ data_end = (void *)(long)skb->data_end;
+ data = (void *)(long)skb->data;
+
+ ret = syncookie_part2(skb, data, data_end, &hdr, false);
+ switch (ret) {
+ case XDP_PASS:
+ return TC_ACT_OK;
+ case XDP_TX:
+ return bpf_redirect(skb->ifindex, 0);
+ default:
+ return TC_ACT_SHOT;
+ }
}

char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/xdp_synproxy.c b/tools/testing/selftests/bpf/xdp_synproxy.c
index 4653d4655b5f..d874ddfb39c4 100644
--- a/tools/testing/selftests/bpf/xdp_synproxy.c
+++ b/tools/testing/selftests/bpf/xdp_synproxy.c
@@ -18,16 +18,31 @@

static unsigned int ifindex;
static __u32 attached_prog_id;
+static bool attached_tc;

static void noreturn cleanup(int sig)
{
- DECLARE_LIBBPF_OPTS(bpf_xdp_attach_opts, opts);
+ LIBBPF_OPTS(bpf_xdp_attach_opts, opts);
int prog_fd;
int err;

if (attached_prog_id == 0)
exit(0);

+ if (attached_tc) {
+ LIBBPF_OPTS(bpf_tc_hook, hook,
+ .ifindex = ifindex,
+ .attach_point = BPF_TC_INGRESS);
+
+ err = bpf_tc_hook_destroy(&hook);
+ if (err < 0) {
+ fprintf(stderr, "Error: bpf_tc_hook_destroy: %s\n", strerror(-err));
+ fprintf(stderr, "Failed to destroy the TC hook\n");
+ exit(1);
+ }
+ exit(0);
+ }
+
prog_fd = bpf_prog_get_fd_by_id(attached_prog_id);
if (prog_fd < 0) {
fprintf(stderr, "Error: bpf_prog_get_fd_by_id: %s\n", strerror(-prog_fd));
@@ -55,7 +70,7 @@ static void noreturn cleanup(int sig)

static noreturn void usage(const char *progname)
{
- fprintf(stderr, "Usage: %s [--iface <iface>|--prog <prog_id>] [--mss4 <mss ipv4> --mss6 <mss ipv6> --wscale <wscale> --ttl <ttl>] [--ports <port1>,<port2>,...] [--single]\n",
+ fprintf(stderr, "Usage: %s [--iface <iface>|--prog <prog_id>] [--mss4 <mss ipv4> --mss6 <mss ipv6> --wscale <wscale> --ttl <ttl>] [--ports <port1>,<port2>,...] [--single] [--tc]\n",
progname);
exit(1);
}
@@ -74,7 +89,7 @@ static unsigned long parse_arg_ul(const char *progname, const char *arg, unsigne
}

static void parse_options(int argc, char *argv[], unsigned int *ifindex, __u32 *prog_id,
- __u64 *tcpipopts, char **ports, bool *single)
+ __u64 *tcpipopts, char **ports, bool *single, bool *tc)
{
static struct option long_options[] = {
{ "help", no_argument, NULL, 'h' },
@@ -86,6 +101,7 @@ static void parse_options(int argc, char *argv[], unsigned int *ifindex, __u32 *
{ "ttl", required_argument, NULL, 't' },
{ "ports", required_argument, NULL, 'p' },
{ "single", no_argument, NULL, 's' },
+ { "tc", no_argument, NULL, 'c' },
{ NULL, 0, NULL, 0 },
};
unsigned long mss4, mss6, wscale, ttl;
@@ -143,6 +159,9 @@ static void parse_options(int argc, char *argv[], unsigned int *ifindex, __u32 *
case 's':
*single = true;
break;
+ case 'c':
+ *tc = true;
+ break;
default:
usage(argv[0]);
}
@@ -164,7 +183,7 @@ static void parse_options(int argc, char *argv[], unsigned int *ifindex, __u32 *
usage(argv[0]);
}

-static int syncookie_attach(const char *argv0, unsigned int ifindex)
+static int syncookie_attach(const char *argv0, unsigned int ifindex, bool tc)
{
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
@@ -188,9 +207,9 @@ static int syncookie_attach(const char *argv0, unsigned int ifindex)
return err;
}

- prog = bpf_object__find_program_by_name(obj, "syncookie_xdp");
+ prog = bpf_object__find_program_by_name(obj, tc ? "syncookie_tc" : "syncookie_xdp");
if (!prog) {
- fprintf(stderr, "Error: bpf_object__find_program_by_name: program syncookie_xdp was not found\n");
+ fprintf(stderr, "Error: bpf_object__find_program_by_name: program was not found\n");
return -ENOENT;
}

@@ -201,21 +220,50 @@ static int syncookie_attach(const char *argv0, unsigned int ifindex)
fprintf(stderr, "Error: bpf_obj_get_info_by_fd: %s\n", strerror(-err));
goto out;
}
+ attached_tc = tc;
attached_prog_id = info.id;
signal(SIGINT, cleanup);
signal(SIGTERM, cleanup);
- err = bpf_xdp_attach(ifindex, prog_fd, XDP_FLAGS_UPDATE_IF_NOEXIST, NULL);
- if (err < 0) {
- fprintf(stderr, "Error: bpf_set_link_xdp_fd: %s\n", strerror(-err));
- signal(SIGINT, SIG_DFL);
- signal(SIGTERM, SIG_DFL);
- attached_prog_id = 0;
- goto out;
+ if (tc) {
+ LIBBPF_OPTS(bpf_tc_hook, hook,
+ .ifindex = ifindex,
+ .attach_point = BPF_TC_INGRESS);
+ LIBBPF_OPTS(bpf_tc_opts, opts,
+ .handle = 1,
+ .priority = 1,
+ .prog_fd = prog_fd);
+
+ err = bpf_tc_hook_create(&hook);
+ if (err < 0) {
+ fprintf(stderr, "Error: bpf_tc_hook_create: %s\n",
+ strerror(-err));
+ goto fail;
+ }
+ err = bpf_tc_attach(&hook, &opts);
+ if (err < 0) {
+ fprintf(stderr, "Error: bpf_tc_attach: %s\n",
+ strerror(-err));
+ goto fail;
+ }
+
+ } else {
+ err = bpf_xdp_attach(ifindex, prog_fd,
+ XDP_FLAGS_UPDATE_IF_NOEXIST, NULL);
+ if (err < 0) {
+ fprintf(stderr, "Error: bpf_set_link_xdp_fd: %s\n",
+ strerror(-err));
+ goto fail;
+ }
}
err = 0;
out:
bpf_object__close(obj);
return err;
+fail:
+ signal(SIGINT, SIG_DFL);
+ signal(SIGTERM, SIG_DFL);
+ attached_prog_id = 0;
+ goto out;
}

static int syncookie_open_bpf_maps(__u32 prog_id, int *values_map_fd, int *ports_map_fd)
@@ -248,11 +296,6 @@ static int syncookie_open_bpf_maps(__u32 prog_id, int *values_map_fd, int *ports
goto out;
}

- if (prog_info.type != BPF_PROG_TYPE_XDP) {
- fprintf(stderr, "Error: BPF prog type is not BPF_PROG_TYPE_XDP\n");
- err = -ENOENT;
- goto out;
- }
if (prog_info.nr_map_ids < 2) {
fprintf(stderr, "Error: Found %u BPF maps, expected at least 2\n",
prog_info.nr_map_ids);
@@ -319,17 +362,22 @@ int main(int argc, char *argv[])
char *ports;
bool single;
int err = 0;
+ bool tc;

- parse_options(argc, argv, &ifindex, &prog_id, &tcpipopts, &ports, &single);
+ parse_options(argc, argv, &ifindex, &prog_id, &tcpipopts, &ports,
+ &single, &tc);

if (prog_id == 0) {
- err = bpf_xdp_query_id(ifindex, 0, &prog_id);
- if (err < 0) {
- fprintf(stderr, "Error: bpf_get_link_xdp_id: %s\n", strerror(-err));
- goto out;
+ if (!tc) {
+ err = bpf_xdp_query_id(ifindex, 0, &prog_id);
+ if (err < 0) {
+ fprintf(stderr, "Error: bpf_get_link_xdp_id: %s\n",
+ strerror(-err));
+ goto out;
+ }
}
if (prog_id == 0) {
- err = syncookie_attach(argv[0], ifindex);
+ err = syncookie_attach(argv[0], ifindex, tc);
if (err < 0)
goto out;
prog_id = attached_prog_id;
--
2.30.2