selftests/bpf: Add selftests for raw syncookie helpers in TC mode
authorMaxim Mikityanskiy <maximmi@nvidia.com>
Wed, 15 Jun 2022 13:48:47 +0000 (16:48 +0300)
committerAlexei Starovoitov <ast@kernel.org>
Fri, 17 Jun 2022 04:20:30 +0000 (21:20 -0700)
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>
Link: https://lore.kernel.org/r/20220615134847.3753567-7-maximmi@nvidia.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
tools/testing/selftests/bpf/prog_tests/xdp_synproxy.c
tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c
tools/testing/selftests/bpf/xdp_synproxy.c

index d9ee884..fb77a12 100644 (file)
@@ -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>
                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 @@ out:
        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);
+}
index 53b9865..9fd62e9 100644 (file)
@@ -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";
index 4653d46..d874ddf 100644 (file)
 
 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;