From patchwork Wed Sep 7 18:31:29 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joanne Koong X-Patchwork-Id: 12969321 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 36529C38145 for ; Wed, 7 Sep 2022 18:36:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229487AbiIGSgB (ORCPT ); Wed, 7 Sep 2022 14:36:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55736 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229485AbiIGSgA (ORCPT ); Wed, 7 Sep 2022 14:36:00 -0400 Received: from 69-171-232-181.mail-mxout.facebook.com (69-171-232-181.mail-mxout.facebook.com [69.171.232.181]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 749C5BCCF7 for ; Wed, 7 Sep 2022 11:35:54 -0700 (PDT) Received: by devbig010.atn6.facebook.com (Postfix, from userid 115148) id D037D116DA114; Wed, 7 Sep 2022 11:32:51 -0700 (PDT) From: Joanne Koong To: bpf@vger.kernel.org Cc: andrii@kernel.org, daniel@iogearbox.net, ast@kernel.org, martin.lau@kernel.org, kuba@kernel.org, memxor@gmail.com, toke@redhat.com, netdev@vger.kernel.org, kernel-team@fb.com, Joanne Koong Subject: [PATCH bpf-next v6 3/3] selftests/bpf: tests for using dynptrs to parse skb and xdp buffers Date: Wed, 7 Sep 2022 11:31:29 -0700 Message-Id: <20220907183129.745846-4-joannelkoong@gmail.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220907183129.745846-1-joannelkoong@gmail.com> References: <20220907183129.745846-1-joannelkoong@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Test skb and xdp dynptr functionality in the following ways: 1) progs/test_cls_redirect_dynptr.c * Rewrite "progs/test_cls_redirect.c" test to use dynptrs to parse skb data * This is a great example of how dynptrs can be used to simplify a lot of the parsing logic for non-statically known values, and speed up execution times. When measuring the user + system time between the original version vs. using dynptrs, and averaging the time for 10 runs (using "time ./test_progs -t cls_redirect"), there was a 2x speed-up: original version: 0.053 sec with dynptrs: 0.025 sec 2) progs/test_xdp_dynptr.c * Rewrite "progs/test_xdp.c" test to use dynptrs to parse xdp data There were no noticeable diferences in user + system time between the original version vs. using dynptrs. Averaging the time for 10 runs (run using "time ./test_progs -t xdp_attach"): original version: 0.011 sec with dynptrs: 0.011 sec 3) progs/test_l4lb_noinline_dynptr.c * Rewrite "progs/test_l4lb_noinline.c" test to use dynptrs to parse skb data There were no noticeable diferences in user + system time between the original version vs. using dynptrs. Averaging the time for 10 runs (run using "time ./test_progs -t l4lb_all"): original version: 0.0502 sec with dynptrs: 0.055 sec For number of processed verifier instructions: original version: 6284 insns with dynptrs: 2538 insns 4) progs/test_parse_tcp_hdr_opt_dynptr.c * Add sample code for parsing tcp hdr opt lookup using dynptrs. This logic is lifted from a real-world use case of packet parsing in katran [0], a layer 4 load balancer. The original version "progs/test_parse_tcp_hdr_opt.c" (not using dynptrs) is included here as well, for comparison. There were no noticeable diferences in user + system time between the original version vs. using dynptrs. Averaging the time for 10 runs (run using "time ./test_progs -t parse_tcp_hdr_opt"): original version: 0.007 sec with dynptrs: 0.008 sec 5) progs/dynptr_success.c * Add test case "test_skb_readonly" for testing attempts at writes / data slices on a prog type with read-only skb ctx. 6) progs/dynptr_fail.c * Add test cases "skb_invalid_data_slice{1,2}" and "xdp_invalid_data_slice" for testing that helpers that modify the underlying packet buffer automatically invalidate the associated data slice. * Add test cases "skb_invalid_ctx" and "xdp_invalid_ctx" for testing that prog types that do not support bpf_dynptr_from_skb/xdp don't have access to the API. [0] https://github.com/facebookincubator/katran/blob/main/katran/lib/bpf/pckt_parsing.h Signed-off-by: Joanne Koong Acked-by: Andrii Nakryiko --- .../selftests/bpf/prog_tests/cls_redirect.c | 25 + .../testing/selftests/bpf/prog_tests/dynptr.c | 73 +- .../selftests/bpf/prog_tests/l4lb_all.c | 2 + .../bpf/prog_tests/parse_tcp_hdr_opt.c | 93 ++ .../selftests/bpf/prog_tests/xdp_attach.c | 11 +- .../testing/selftests/bpf/progs/dynptr_fail.c | 92 ++ .../selftests/bpf/progs/dynptr_success.c | 32 + .../bpf/progs/test_cls_redirect_dynptr.c | 968 ++++++++++++++++++ .../bpf/progs/test_l4lb_noinline_dynptr.c | 469 +++++++++ .../bpf/progs/test_parse_tcp_hdr_opt.c | 119 +++ .../bpf/progs/test_parse_tcp_hdr_opt_dynptr.c | 110 ++ .../selftests/bpf/progs/test_xdp_dynptr.c | 235 +++++ .../selftests/bpf/test_tcp_hdr_options.h | 1 + 13 files changed, 2214 insertions(+), 16 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/parse_tcp_hdr_opt.c create mode 100644 tools/testing/selftests/bpf/progs/test_cls_redirect_dynptr.c create mode 100644 tools/testing/selftests/bpf/progs/test_l4lb_noinline_dynptr.c create mode 100644 tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt.c create mode 100644 tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt_dynptr.c create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_dynptr.c diff --git a/tools/testing/selftests/bpf/prog_tests/cls_redirect.c b/tools/testing/selftests/bpf/prog_tests/cls_redirect.c index 224f016b0a53..2a55f717fc07 100644 --- a/tools/testing/selftests/bpf/prog_tests/cls_redirect.c +++ b/tools/testing/selftests/bpf/prog_tests/cls_redirect.c @@ -13,6 +13,7 @@ #include "progs/test_cls_redirect.h" #include "test_cls_redirect.skel.h" +#include "test_cls_redirect_dynptr.skel.h" #include "test_cls_redirect_subprogs.skel.h" #define ENCAP_IP INADDR_LOOPBACK @@ -446,6 +447,28 @@ static void test_cls_redirect_common(struct bpf_program *prog) close_fds((int *)conns, sizeof(conns) / sizeof(conns[0][0])); } +static void test_cls_redirect_dynptr(void) +{ + struct test_cls_redirect_dynptr *skel; + int err; + + skel = test_cls_redirect_dynptr__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + skel->rodata->ENCAPSULATION_IP = htonl(ENCAP_IP); + skel->rodata->ENCAPSULATION_PORT = htons(ENCAP_PORT); + + err = test_cls_redirect_dynptr__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto cleanup; + + test_cls_redirect_common(skel->progs.cls_redirect); + +cleanup: + test_cls_redirect_dynptr__destroy(skel); +} + static void test_cls_redirect_inlined(void) { struct test_cls_redirect *skel; @@ -496,4 +519,6 @@ void test_cls_redirect(void) test_cls_redirect_inlined(); if (test__start_subtest("cls_redirect_subprogs")) test_cls_redirect_subprogs(); + if (test__start_subtest("cls_redirect_dynptr")) + test_cls_redirect_dynptr(); } diff --git a/tools/testing/selftests/bpf/prog_tests/dynptr.c b/tools/testing/selftests/bpf/prog_tests/dynptr.c index bcf80b9f7c27..f3bdec4a595c 100644 --- a/tools/testing/selftests/bpf/prog_tests/dynptr.c +++ b/tools/testing/selftests/bpf/prog_tests/dynptr.c @@ -2,17 +2,26 @@ /* Copyright (c) 2022 Facebook */ #include +#include #include "dynptr_fail.skel.h" #include "dynptr_success.skel.h" static size_t log_buf_sz = 1048576; /* 1 MB */ static char obj_log_buf[1048576]; +enum test_setup_type { + /* no set up is required. the prog will just be loaded */ + SETUP_NONE, + SETUP_SYSCALL_SLEEP, + SETUP_SKB_PROG, +}; + static struct { const char *prog_name; const char *expected_err_msg; + enum test_setup_type type; } dynptr_tests[] = { - /* failure cases */ + /* these cases should trigger a verifier error */ {"ringbuf_missing_release1", "Unreleased reference id=1"}, {"ringbuf_missing_release2", "Unreleased reference id=2"}, {"ringbuf_missing_release_callback", "Unreleased reference id"}, @@ -42,11 +51,17 @@ static struct { {"release_twice_callback", "arg 1 is an unacquired reference"}, {"dynptr_from_mem_invalid_api", "Unsupported reg type fp for bpf_dynptr_from_mem data"}, - - /* success cases */ - {"test_read_write", NULL}, - {"test_data_slice", NULL}, - {"test_ringbuf", NULL}, + {"skb_invalid_data_slice1", "invalid mem access 'scalar'"}, + {"skb_invalid_data_slice2", "invalid mem access 'scalar'"}, + {"xdp_invalid_data_slice", "invalid mem access 'scalar'"}, + {"skb_invalid_ctx", "unknown func bpf_dynptr_from_skb"}, + {"xdp_invalid_ctx", "unknown func bpf_dynptr_from_xdp"}, + + /* these tests should be run and should succeed */ + {"test_read_write", NULL, SETUP_SYSCALL_SLEEP}, + {"test_data_slice", NULL, SETUP_SYSCALL_SLEEP}, + {"test_ringbuf", NULL, SETUP_SYSCALL_SLEEP}, + {"test_skb_readonly", NULL, SETUP_SKB_PROG}, }; static void verify_fail(const char *prog_name, const char *expected_err_msg) @@ -85,7 +100,7 @@ static void verify_fail(const char *prog_name, const char *expected_err_msg) dynptr_fail__destroy(skel); } -static void verify_success(const char *prog_name) +static void run_test(const char *prog_name, enum test_setup_type setup_type) { struct dynptr_success *skel; struct bpf_program *prog; @@ -107,15 +122,45 @@ static void verify_success(const char *prog_name) if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) goto cleanup; - link = bpf_program__attach(prog); - if (!ASSERT_OK_PTR(link, "bpf_program__attach")) - goto cleanup; + switch (setup_type) { + case SETUP_SYSCALL_SLEEP: + link = bpf_program__attach(prog); + if (!ASSERT_OK_PTR(link, "bpf_program__attach")) + goto cleanup; - usleep(1); + usleep(1); - ASSERT_EQ(skel->bss->err, 0, "err"); + bpf_link__destroy(link); + break; + case SETUP_SKB_PROG: + { + int prog_fd, err; + char buf[64]; + + LIBBPF_OPTS(bpf_test_run_opts, topts, + .data_in = &pkt_v4, + .data_size_in = sizeof(pkt_v4), + .data_out = buf, + .data_size_out = sizeof(buf), + .repeat = 1, + ); + + prog_fd = bpf_program__fd(prog); + if (!ASSERT_GE(prog_fd, 0, "prog_fd")) + goto cleanup; - bpf_link__destroy(link); + err = bpf_prog_test_run_opts(prog_fd, &topts); + + if (!ASSERT_OK(err, "test_run")) + goto cleanup; + + break; + } + case SETUP_NONE: + ASSERT_EQ(0, 1, "internal error: SETUP_NONE unimplemented"); + } + + ASSERT_EQ(skel->bss->err, 0, "err"); cleanup: dynptr_success__destroy(skel); @@ -133,6 +178,6 @@ void test_dynptr(void) verify_fail(dynptr_tests[i].prog_name, dynptr_tests[i].expected_err_msg); else - verify_success(dynptr_tests[i].prog_name); + run_test(dynptr_tests[i].prog_name, dynptr_tests[i].type); } } diff --git a/tools/testing/selftests/bpf/prog_tests/l4lb_all.c b/tools/testing/selftests/bpf/prog_tests/l4lb_all.c index 55f733ff4109..94079c89f2e9 100644 --- a/tools/testing/selftests/bpf/prog_tests/l4lb_all.c +++ b/tools/testing/selftests/bpf/prog_tests/l4lb_all.c @@ -93,4 +93,6 @@ void test_l4lb_all(void) test_l4lb("test_l4lb.o"); if (test__start_subtest("l4lb_noinline")) test_l4lb("test_l4lb_noinline.o"); + if (test__start_subtest("l4lb_noinline_dynptr")) + test_l4lb("test_l4lb_noinline_dynptr.o"); } diff --git a/tools/testing/selftests/bpf/prog_tests/parse_tcp_hdr_opt.c b/tools/testing/selftests/bpf/prog_tests/parse_tcp_hdr_opt.c new file mode 100644 index 000000000000..ab042fdcfe55 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/parse_tcp_hdr_opt.c @@ -0,0 +1,93 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include "test_parse_tcp_hdr_opt.skel.h" +#include "test_parse_tcp_hdr_opt_dynptr.skel.h" +#include "test_tcp_hdr_options.h" + +struct test_pkt { + struct ipv6_packet pk6_v6; + u8 options[16]; +} __packed; + +struct test_pkt pkt = { + .pk6_v6.eth.h_proto = __bpf_constant_htons(ETH_P_IPV6), + .pk6_v6.iph.nexthdr = IPPROTO_TCP, + .pk6_v6.iph.payload_len = __bpf_constant_htons(MAGIC_BYTES), + .pk6_v6.tcp.urg_ptr = 123, + .pk6_v6.tcp.doff = 9, /* 16 bytes of options */ + + .options = { + TCPOPT_MSS, 4, 0x05, 0xB4, TCPOPT_NOP, TCPOPT_NOP, + 0, 6, 0, 0, 0, 9, TCPOPT_EOL + }, +}; + +static void test_parse_opt(void) +{ + struct test_parse_tcp_hdr_opt *skel; + struct bpf_program *prog; + char buf[128]; + int err; + + LIBBPF_OPTS(bpf_test_run_opts, topts, + .data_in = &pkt, + .data_size_in = sizeof(pkt), + .data_out = buf, + .data_size_out = sizeof(buf), + .repeat = 3, + ); + + skel = test_parse_tcp_hdr_opt__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open_and_load")) + return; + + pkt.options[6] = skel->rodata->tcp_hdr_opt_kind_tpr; + prog = skel->progs.xdp_ingress_v6; + + err = bpf_prog_test_run_opts(bpf_program__fd(prog), &topts); + ASSERT_OK(err, "ipv6 test_run"); + ASSERT_EQ(topts.retval, XDP_PASS, "ipv6 test_run retval"); + ASSERT_EQ(skel->bss->server_id, 0x9000000, "server id"); + + test_parse_tcp_hdr_opt__destroy(skel); +} + +static void test_parse_opt_dynptr(void) +{ + struct test_parse_tcp_hdr_opt_dynptr *skel; + struct bpf_program *prog; + char buf[128]; + int err; + + LIBBPF_OPTS(bpf_test_run_opts, topts, + .data_in = &pkt, + .data_size_in = sizeof(pkt), + .data_out = buf, + .data_size_out = sizeof(buf), + .repeat = 3, + ); + + skel = test_parse_tcp_hdr_opt_dynptr__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open_and_load")) + return; + + pkt.options[6] = skel->rodata->tcp_hdr_opt_kind_tpr; + prog = skel->progs.xdp_ingress_v6; + + err = bpf_prog_test_run_opts(bpf_program__fd(prog), &topts); + ASSERT_OK(err, "ipv6 test_run"); + ASSERT_EQ(topts.retval, XDP_PASS, "ipv6 test_run retval"); + ASSERT_EQ(skel->bss->server_id, 0x9000000, "server id"); + + test_parse_tcp_hdr_opt_dynptr__destroy(skel); +} + +void test_parse_tcp_hdr_opt(void) +{ + if (test__start_subtest("parse_tcp_hdr_opt")) + test_parse_opt(); + if (test__start_subtest("parse_tcp_hdr_opt_dynptr")) + test_parse_opt_dynptr(); +} diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c index 62aa3edda5e6..5fb5f03022d3 100644 --- a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c +++ b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c @@ -4,11 +4,10 @@ #define IFINDEX_LO 1 #define XDP_FLAGS_REPLACE (1U << 4) -void serial_test_xdp_attach(void) +static void serial_test_xdp_attach(const char *file) { __u32 duration = 0, id1, id2, id0 = 0, len; struct bpf_object *obj1, *obj2, *obj3; - const char *file = "./test_xdp.o"; struct bpf_prog_info info = {}; int err, fd1, fd2, fd3; LIBBPF_OPTS(bpf_xdp_attach_opts, opts); @@ -85,3 +84,11 @@ void serial_test_xdp_attach(void) out_1: bpf_object__close(obj1); } + +void test_xdp_attach(void) +{ + if (test__start_subtest("xdp_attach")) + serial_test_xdp_attach("./test_xdp.o"); + if (test__start_subtest("xdp_attach_dynptr")) + serial_test_xdp_attach("./test_xdp_dynptr.o"); +} diff --git a/tools/testing/selftests/bpf/progs/dynptr_fail.c b/tools/testing/selftests/bpf/progs/dynptr_fail.c index b0f08ff024fb..2da6703d0caf 100644 --- a/tools/testing/selftests/bpf/progs/dynptr_fail.c +++ b/tools/testing/selftests/bpf/progs/dynptr_fail.c @@ -5,6 +5,7 @@ #include #include #include +#include #include "bpf_misc.h" char _license[] SEC("license") = "GPL"; @@ -622,3 +623,94 @@ int dynptr_from_mem_invalid_api(void *ctx) return 0; } + +/* The data slice is invalidated whenever a helper changes packet data */ +SEC("?tc") +int skb_invalid_data_slice1(struct __sk_buff *skb) +{ + struct bpf_dynptr ptr; + struct ethhdr *hdr; + + bpf_dynptr_from_skb(skb, 0, &ptr); + hdr = bpf_dynptr_data(&ptr, 0, sizeof(*hdr)); + + if (bpf_skb_pull_data(skb, skb->len)) + return SK_DROP; + + if (!hdr) + return SK_DROP; + + /* this should fail */ + hdr->h_proto = 1; + + return SK_PASS; +} + +/* The data slice is invalidated whenever bpf_dynptr_write() is called */ +SEC("?tc") +int skb_invalid_data_slice2(struct __sk_buff *skb) +{ + char write_data[64] = "hello there, world!!"; + struct bpf_dynptr ptr; + struct ethhdr *hdr; + + bpf_dynptr_from_skb(skb, 0, &ptr); + hdr = bpf_dynptr_data(&ptr, 0, sizeof(*hdr)); + + bpf_dynptr_write(&ptr, 0, write_data, sizeof(write_data), 0); + + if (!hdr) + return SK_DROP; + + /* this should fail */ + hdr->h_proto = 1; + + return SK_PASS; +} + +/* The data slice is invalidated whenever a helper changes packet data */ +SEC("?xdp") +int xdp_invalid_data_slice(struct xdp_md *xdp) +{ + struct bpf_dynptr ptr; + struct ethhdr *hdr; + + bpf_dynptr_from_xdp(xdp, 0, &ptr); + hdr = bpf_dynptr_data(&ptr, 0, sizeof(*hdr)); + if (!hdr) + return SK_DROP; + + hdr->h_proto = 9; + + if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(*hdr))) + return XDP_DROP; + + /* this should fail */ + hdr->h_proto = 1; + + return XDP_PASS; +} + +/* Only supported prog type can create skb-type dynptrs */ +SEC("?raw_tp") +int skb_invalid_ctx(void *ctx) +{ + struct bpf_dynptr ptr; + + /* this should fail */ + bpf_dynptr_from_skb(ctx, 0, &ptr); + + return 0; +} + +/* Only supported prog type can create xdp-type dynptrs */ +SEC("?raw_tp") +int xdp_invalid_ctx(void *ctx) +{ + struct bpf_dynptr ptr; + + /* this should fail */ + bpf_dynptr_from_xdp(ctx, 0, &ptr); + + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/dynptr_success.c b/tools/testing/selftests/bpf/progs/dynptr_success.c index a3a6103c8569..8ed3ef201284 100644 --- a/tools/testing/selftests/bpf/progs/dynptr_success.c +++ b/tools/testing/selftests/bpf/progs/dynptr_success.c @@ -162,3 +162,35 @@ int test_ringbuf(void *ctx) bpf_ringbuf_discard_dynptr(&ptr, 0); return 0; } + +SEC("cgroup_skb/egress") +int test_skb_readonly(struct __sk_buff *skb) +{ + __u8 write_data[2] = {1, 2}; + struct bpf_dynptr ptr; + __u64 *data; + int ret; + + if (bpf_dynptr_from_skb(skb, 0, &ptr)) { + err = 1; + return 0; + } + + data = bpf_dynptr_data(&ptr, 0, sizeof(*data)); + /* since cgroup skbs are read only, bpf_dynptr_data + * should always return NULL + */ + if (data) { + err = 2; + return 0; + } + + /* since cgroup skbs are read only, writes should fail */ + ret = bpf_dynptr_write(&ptr, 0, write_data, sizeof(write_data), 0); + if (ret != -EINVAL) { + err = 3; + return 0; + } + + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/test_cls_redirect_dynptr.c b/tools/testing/selftests/bpf/progs/test_cls_redirect_dynptr.c new file mode 100644 index 000000000000..40e5e7ef0228 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_cls_redirect_dynptr.c @@ -0,0 +1,968 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause +// Copyright (c) 2019, 2020 Cloudflare + +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "test_cls_redirect.h" + +#define offsetofend(TYPE, MEMBER) \ + (offsetof(TYPE, MEMBER) + sizeof((((TYPE *)0)->MEMBER))) + +#define IP_OFFSET_MASK (0x1FFF) +#define IP_MF (0x2000) + +char _license[] SEC("license") = "Dual BSD/GPL"; + +/** + * Destination port and IP used for UDP encapsulation. + */ +volatile const __be16 ENCAPSULATION_PORT; +volatile const __be32 ENCAPSULATION_IP; + +typedef struct { + uint64_t processed_packets_total; + uint64_t l3_protocol_packets_total_ipv4; + uint64_t l3_protocol_packets_total_ipv6; + uint64_t l4_protocol_packets_total_tcp; + uint64_t l4_protocol_packets_total_udp; + uint64_t accepted_packets_total_syn; + uint64_t accepted_packets_total_syn_cookies; + uint64_t accepted_packets_total_last_hop; + uint64_t accepted_packets_total_icmp_echo_request; + uint64_t accepted_packets_total_established; + uint64_t forwarded_packets_total_gue; + uint64_t forwarded_packets_total_gre; + + uint64_t errors_total_unknown_l3_proto; + uint64_t errors_total_unknown_l4_proto; + uint64_t errors_total_malformed_ip; + uint64_t errors_total_fragmented_ip; + uint64_t errors_total_malformed_icmp; + uint64_t errors_total_unwanted_icmp; + uint64_t errors_total_malformed_icmp_pkt_too_big; + uint64_t errors_total_malformed_tcp; + uint64_t errors_total_malformed_udp; + uint64_t errors_total_icmp_echo_replies; + uint64_t errors_total_malformed_encapsulation; + uint64_t errors_total_encap_adjust_failed; + uint64_t errors_total_encap_buffer_too_small; + uint64_t errors_total_redirect_loop; + uint64_t errors_total_encap_mtu_violate; +} metrics_t; + +typedef enum { + INVALID = 0, + UNKNOWN, + ECHO_REQUEST, + SYN, + SYN_COOKIE, + ESTABLISHED, +} verdict_t; + +typedef struct { + uint16_t src, dst; +} flow_ports_t; + +_Static_assert( + sizeof(flow_ports_t) != + offsetofend(struct bpf_sock_tuple, ipv4.dport) - + offsetof(struct bpf_sock_tuple, ipv4.sport) - 1, + "flow_ports_t must match sport and dport in struct bpf_sock_tuple"); +_Static_assert( + sizeof(flow_ports_t) != + offsetofend(struct bpf_sock_tuple, ipv6.dport) - + offsetof(struct bpf_sock_tuple, ipv6.sport) - 1, + "flow_ports_t must match sport and dport in struct bpf_sock_tuple"); + +struct iphdr_info { + void *hdr; + __u64 len; +}; + +typedef int ret_t; + +/* This is a bit of a hack. We need a return value which allows us to + * indicate that the regular flow of the program should continue, + * while allowing functions to use XDP_PASS and XDP_DROP, etc. + */ +static const ret_t CONTINUE_PROCESSING = -1; + +/* Convenience macro to call functions which return ret_t. + */ +#define MAYBE_RETURN(x) \ + do { \ + ret_t __ret = x; \ + if (__ret != CONTINUE_PROCESSING) \ + return __ret; \ + } while (0) + +static bool ipv4_is_fragment(const struct iphdr *ip) +{ + uint16_t frag_off = ip->frag_off & bpf_htons(IP_OFFSET_MASK); + return (ip->frag_off & bpf_htons(IP_MF)) != 0 || frag_off > 0; +} + +static int pkt_parse_ipv4(struct bpf_dynptr *dynptr, __u64 *offset, struct iphdr *iphdr) +{ + if (bpf_dynptr_read(iphdr, sizeof(*iphdr), dynptr, *offset, 0)) + return -1; + + *offset += sizeof(*iphdr); + + if (iphdr->ihl < 5) + return -1; + + /* skip ipv4 options */ + *offset += (iphdr->ihl - 5) * 4; + + return 0; +} + +/* Parse the L4 ports from a packet, assuming a layout like TCP or UDP. */ +static bool pkt_parse_icmp_l4_ports(struct bpf_dynptr *dynptr, __u64 *offset, flow_ports_t *ports) +{ + if (bpf_dynptr_read(ports, sizeof(*ports), dynptr, *offset, 0)) + return false; + + *offset += sizeof(*ports); + + /* Ports in the L4 headers are reversed, since we are parsing an ICMP + * payload which is going towards the eyeball. + */ + uint16_t dst = ports->src; + ports->src = ports->dst; + ports->dst = dst; + return true; +} + +static uint16_t pkt_checksum_fold(uint32_t csum) +{ + /* The highest reasonable value for an IPv4 header + * checksum requires two folds, so we just do that always. + */ + csum = (csum & 0xffff) + (csum >> 16); + csum = (csum & 0xffff) + (csum >> 16); + return (uint16_t)~csum; +} + +static void pkt_ipv4_checksum(struct iphdr *iph) +{ + iph->check = 0; + + /* An IP header without options is 20 bytes. Two of those + * are the checksum, which we always set to zero. Hence, + * the maximum accumulated value is 18 / 2 * 0xffff = 0x8fff7, + * which fits in 32 bit. + */ + _Static_assert(sizeof(struct iphdr) == 20, "iphdr must be 20 bytes"); + uint32_t acc = 0; + uint16_t *ipw = (uint16_t *)iph; + + for (size_t i = 0; i < sizeof(struct iphdr) / 2; i++) + acc += ipw[i]; + + iph->check = pkt_checksum_fold(acc); +} + +static bool pkt_skip_ipv6_extension_headers(struct bpf_dynptr *dynptr, __u64 *offset, + const struct ipv6hdr *ipv6, uint8_t *upper_proto, + bool *is_fragment) +{ + /* We understand five extension headers. + * https://tools.ietf.org/html/rfc8200#section-4.1 states that all + * headers should occur once, except Destination Options, which may + * occur twice. Hence we give up after 6 headers. + */ + struct { + uint8_t next; + uint8_t len; + } exthdr = { + .next = ipv6->nexthdr, + }; + *is_fragment = false; + + for (int i = 0; i < 6; i++) { + switch (exthdr.next) { + case IPPROTO_FRAGMENT: + *is_fragment = true; + /* NB: We don't check that hdrlen == 0 as per spec. */ + /* fallthrough; */ + + case IPPROTO_HOPOPTS: + case IPPROTO_ROUTING: + case IPPROTO_DSTOPTS: + case IPPROTO_MH: + if (bpf_dynptr_read(&exthdr, sizeof(exthdr), dynptr, *offset, 0)) + return false; + + /* hdrlen is in 8-octet units, and excludes the first 8 octets. */ + *offset += (exthdr.len + 1) * 8; + + /* Decode next header */ + break; + + default: + /* The next header is not one of the known extension + * headers, treat it as the upper layer header. + * + * This handles IPPROTO_NONE. + * + * Encapsulating Security Payload (50) and Authentication + * Header (51) also end up here (and will trigger an + * unknown proto error later). They have a custom header + * format and seem too esoteric to care about. + */ + *upper_proto = exthdr.next; + return true; + } + } + + /* We never found an upper layer header. */ + return false; +} + +static int pkt_parse_ipv6(struct bpf_dynptr *dynptr, __u64 *offset, struct ipv6hdr *ipv6, + uint8_t *proto, bool *is_fragment) +{ + if (bpf_dynptr_read(ipv6, sizeof(*ipv6), dynptr, *offset, 0)) + return -1; + + *offset += sizeof(*ipv6); + + if (!pkt_skip_ipv6_extension_headers(dynptr, offset, ipv6, proto, is_fragment)) + return -1; + + return 0; +} + +/* Global metrics, per CPU + */ +struct { + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); + __uint(max_entries, 1); + __type(key, unsigned int); + __type(value, metrics_t); +} metrics_map SEC(".maps"); + +static metrics_t *get_global_metrics(void) +{ + uint64_t key = 0; + return bpf_map_lookup_elem(&metrics_map, &key); +} + +static ret_t accept_locally(struct __sk_buff *skb, encap_headers_t *encap) +{ + const int payload_off = + sizeof(*encap) + + sizeof(struct in_addr) * encap->unigue.hop_count; + int32_t encap_overhead = payload_off - sizeof(struct ethhdr); + + /* Changing the ethertype if the encapsulated packet is ipv6 */ + if (encap->gue.proto_ctype == IPPROTO_IPV6) + encap->eth.h_proto = bpf_htons(ETH_P_IPV6); + + if (bpf_skb_adjust_room(skb, -encap_overhead, BPF_ADJ_ROOM_MAC, + BPF_F_ADJ_ROOM_FIXED_GSO | + BPF_F_ADJ_ROOM_NO_CSUM_RESET) || + bpf_csum_level(skb, BPF_CSUM_LEVEL_DEC)) + return TC_ACT_SHOT; + + return bpf_redirect(skb->ifindex, BPF_F_INGRESS); +} + +static ret_t forward_with_gre(struct __sk_buff *skb, struct bpf_dynptr *dynptr, + encap_headers_t *encap, struct in_addr *next_hop, + metrics_t *metrics) +{ + const int payload_off = + sizeof(*encap) + + sizeof(struct in_addr) * encap->unigue.hop_count; + int32_t encap_overhead = + payload_off - sizeof(struct ethhdr) - sizeof(struct iphdr); + int32_t delta = sizeof(struct gre_base_hdr) - encap_overhead; + uint16_t proto = ETH_P_IP; + uint32_t mtu_len = 0; + encap_gre_t *encap_gre; + + metrics->forwarded_packets_total_gre++; + + /* Loop protection: the inner packet's TTL is decremented as a safeguard + * against any forwarding loop. As the only interesting field is the TTL + * hop limit for IPv6, it is easier to use bpf_skb_load_bytes/bpf_skb_store_bytes + * as they handle the split packets if needed (no need for the data to be + * in the linear section). + */ + if (encap->gue.proto_ctype == IPPROTO_IPV6) { + proto = ETH_P_IPV6; + uint8_t ttl; + int rc; + + rc = bpf_skb_load_bytes( + skb, payload_off + offsetof(struct ipv6hdr, hop_limit), + &ttl, 1); + if (rc != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + if (ttl == 0) { + metrics->errors_total_redirect_loop++; + return TC_ACT_SHOT; + } + + ttl--; + rc = bpf_skb_store_bytes( + skb, payload_off + offsetof(struct ipv6hdr, hop_limit), + &ttl, 1, 0); + if (rc != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + } else { + uint8_t ttl; + int rc; + + rc = bpf_skb_load_bytes( + skb, payload_off + offsetof(struct iphdr, ttl), &ttl, + 1); + if (rc != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + if (ttl == 0) { + metrics->errors_total_redirect_loop++; + return TC_ACT_SHOT; + } + + /* IPv4 also has a checksum to patch. While the TTL is only one byte, + * this function only works for 2 and 4 bytes arguments (the result is + * the same). + */ + rc = bpf_l3_csum_replace( + skb, payload_off + offsetof(struct iphdr, check), ttl, + ttl - 1, 2); + if (rc != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + ttl--; + rc = bpf_skb_store_bytes( + skb, payload_off + offsetof(struct iphdr, ttl), &ttl, 1, + 0); + if (rc != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + } + + if (bpf_check_mtu(skb, skb->ifindex, &mtu_len, delta, 0)) { + metrics->errors_total_encap_mtu_violate++; + return TC_ACT_SHOT; + } + + if (bpf_skb_adjust_room(skb, delta, BPF_ADJ_ROOM_NET, + BPF_F_ADJ_ROOM_FIXED_GSO | + BPF_F_ADJ_ROOM_NO_CSUM_RESET) || + bpf_csum_level(skb, BPF_CSUM_LEVEL_INC)) { + metrics->errors_total_encap_adjust_failed++; + return TC_ACT_SHOT; + } + + if (bpf_skb_pull_data(skb, sizeof(encap_gre_t))) { + metrics->errors_total_encap_buffer_too_small++; + return TC_ACT_SHOT; + } + + encap_gre = bpf_dynptr_data(dynptr, 0, sizeof(encap_gre_t)); + if (!encap_gre) { + metrics->errors_total_encap_buffer_too_small++; + return TC_ACT_SHOT; + } + + encap_gre->ip.protocol = IPPROTO_GRE; + encap_gre->ip.daddr = next_hop->s_addr; + encap_gre->ip.saddr = ENCAPSULATION_IP; + encap_gre->ip.tot_len = + bpf_htons(bpf_ntohs(encap_gre->ip.tot_len) + delta); + encap_gre->gre.flags = 0; + encap_gre->gre.protocol = bpf_htons(proto); + pkt_ipv4_checksum((void *)&encap_gre->ip); + + return bpf_redirect(skb->ifindex, 0); +} + +static ret_t forward_to_next_hop(struct __sk_buff *skb, struct bpf_dynptr *dynptr, + encap_headers_t *encap, struct in_addr *next_hop, + metrics_t *metrics) +{ + /* swap L2 addresses */ + /* This assumes that packets are received from a router. + * So just swapping the MAC addresses here will make the packet go back to + * the router, which will send it to the appropriate machine. + */ + unsigned char temp[ETH_ALEN]; + memcpy(temp, encap->eth.h_dest, sizeof(temp)); + memcpy(encap->eth.h_dest, encap->eth.h_source, + sizeof(encap->eth.h_dest)); + memcpy(encap->eth.h_source, temp, sizeof(encap->eth.h_source)); + + if (encap->unigue.next_hop == encap->unigue.hop_count - 1 && + encap->unigue.last_hop_gre) { + return forward_with_gre(skb, dynptr, encap, next_hop, metrics); + } + + metrics->forwarded_packets_total_gue++; + uint32_t old_saddr = encap->ip.saddr; + encap->ip.saddr = encap->ip.daddr; + encap->ip.daddr = next_hop->s_addr; + if (encap->unigue.next_hop < encap->unigue.hop_count) { + encap->unigue.next_hop++; + } + + /* Remove ip->saddr, add next_hop->s_addr */ + const uint64_t off = offsetof(typeof(*encap), ip.check); + int ret = bpf_l3_csum_replace(skb, off, old_saddr, next_hop->s_addr, 4); + if (ret < 0) { + return TC_ACT_SHOT; + } + + return bpf_redirect(skb->ifindex, 0); +} + +static ret_t skip_next_hops(__u64 *offset, int n) +{ + __u32 res; + switch (n) { + case 1: + *offset += sizeof(struct in_addr); + case 0: + return CONTINUE_PROCESSING; + + default: + return TC_ACT_SHOT; + } +} + +/* Get the next hop from the GLB header. + * + * Sets next_hop->s_addr to 0 if there are no more hops left. + * pkt is positioned just after the variable length GLB header + * iff the call is successful. + */ +static ret_t get_next_hop(struct bpf_dynptr *dynptr, __u64 *offset, encap_headers_t *encap, + struct in_addr *next_hop) +{ + if (encap->unigue.next_hop > encap->unigue.hop_count) + return TC_ACT_SHOT; + + /* Skip "used" next hops. */ + MAYBE_RETURN(skip_next_hops(offset, encap->unigue.next_hop)); + + if (encap->unigue.next_hop == encap->unigue.hop_count) { + /* No more next hops, we are at the end of the GLB header. */ + next_hop->s_addr = 0; + return CONTINUE_PROCESSING; + } + + if (bpf_dynptr_read(next_hop, sizeof(*next_hop), dynptr, *offset, 0)) + return TC_ACT_SHOT; + + *offset += sizeof(*next_hop); + + /* Skip the remainig next hops (may be zero). */ + return skip_next_hops(offset, encap->unigue.hop_count - encap->unigue.next_hop - 1); +} + +/* Fill a bpf_sock_tuple to be used with the socket lookup functions. + * This is a kludge that let's us work around verifier limitations: + * + * fill_tuple(&t, foo, sizeof(struct iphdr), 123, 321) + * + * clang will substitue a costant for sizeof, which allows the verifier + * to track it's value. Based on this, it can figure out the constant + * return value, and calling code works while still being "generic" to + * IPv4 and IPv6. + */ +static uint64_t fill_tuple(struct bpf_sock_tuple *tuple, void *iph, + uint64_t iphlen, uint16_t sport, uint16_t dport) +{ + switch (iphlen) { + case sizeof(struct iphdr): { + struct iphdr *ipv4 = (struct iphdr *)iph; + tuple->ipv4.daddr = ipv4->daddr; + tuple->ipv4.saddr = ipv4->saddr; + tuple->ipv4.sport = sport; + tuple->ipv4.dport = dport; + return sizeof(tuple->ipv4); + } + + case sizeof(struct ipv6hdr): { + struct ipv6hdr *ipv6 = (struct ipv6hdr *)iph; + memcpy(&tuple->ipv6.daddr, &ipv6->daddr, + sizeof(tuple->ipv6.daddr)); + memcpy(&tuple->ipv6.saddr, &ipv6->saddr, + sizeof(tuple->ipv6.saddr)); + tuple->ipv6.sport = sport; + tuple->ipv6.dport = dport; + return sizeof(tuple->ipv6); + } + + default: + return 0; + } +} + +static verdict_t classify_tcp(struct __sk_buff *skb, struct bpf_sock_tuple *tuple, + uint64_t tuplen, void *iph, struct tcphdr *tcp) +{ + struct bpf_sock *sk = + bpf_skc_lookup_tcp(skb, tuple, tuplen, BPF_F_CURRENT_NETNS, 0); + + if (sk == NULL) + return UNKNOWN; + + if (sk->state != BPF_TCP_LISTEN) { + bpf_sk_release(sk); + return ESTABLISHED; + } + + if (iph != NULL && tcp != NULL) { + /* Kludge: we've run out of arguments, but need the length of the ip header. */ + uint64_t iphlen = sizeof(struct iphdr); + + if (tuplen == sizeof(tuple->ipv6)) + iphlen = sizeof(struct ipv6hdr); + + if (bpf_tcp_check_syncookie(sk, iph, iphlen, tcp, + sizeof(*tcp)) == 0) { + bpf_sk_release(sk); + return SYN_COOKIE; + } + } + + bpf_sk_release(sk); + return UNKNOWN; +} + +static verdict_t classify_udp(struct __sk_buff *skb, struct bpf_sock_tuple *tuple, uint64_t tuplen) +{ + struct bpf_sock *sk = + bpf_sk_lookup_udp(skb, tuple, tuplen, BPF_F_CURRENT_NETNS, 0); + + if (sk == NULL) + return UNKNOWN; + + if (sk->state == BPF_TCP_ESTABLISHED) { + bpf_sk_release(sk); + return ESTABLISHED; + } + + bpf_sk_release(sk); + return UNKNOWN; +} + +static verdict_t classify_icmp(struct __sk_buff *skb, uint8_t proto, struct bpf_sock_tuple *tuple, + uint64_t tuplen, metrics_t *metrics) +{ + switch (proto) { + case IPPROTO_TCP: + return classify_tcp(skb, tuple, tuplen, NULL, NULL); + + case IPPROTO_UDP: + return classify_udp(skb, tuple, tuplen); + + default: + metrics->errors_total_malformed_icmp++; + return INVALID; + } +} + +static verdict_t process_icmpv4(struct __sk_buff *skb, struct bpf_dynptr *dynptr, __u64 *offset, + metrics_t *metrics) +{ + struct icmphdr icmp; + struct iphdr ipv4; + + if (bpf_dynptr_read(&icmp, sizeof(icmp), dynptr, *offset, 0)) { + metrics->errors_total_malformed_icmp++; + return INVALID; + } + + *offset += sizeof(icmp); + + /* We should never receive encapsulated echo replies. */ + if (icmp.type == ICMP_ECHOREPLY) { + metrics->errors_total_icmp_echo_replies++; + return INVALID; + } + + if (icmp.type == ICMP_ECHO) + return ECHO_REQUEST; + + if (icmp.type != ICMP_DEST_UNREACH || icmp.code != ICMP_FRAG_NEEDED) { + metrics->errors_total_unwanted_icmp++; + return INVALID; + } + + if (pkt_parse_ipv4(dynptr, offset, &ipv4)) { + metrics->errors_total_malformed_icmp_pkt_too_big++; + return INVALID; + } + + /* The source address in the outer IP header is from the entity that + * originated the ICMP message. Use the original IP header to restore + * the correct flow tuple. + */ + struct bpf_sock_tuple tuple; + tuple.ipv4.saddr = ipv4.daddr; + tuple.ipv4.daddr = ipv4.saddr; + + if (!pkt_parse_icmp_l4_ports(dynptr, offset, (flow_ports_t *)&tuple.ipv4.sport)) { + metrics->errors_total_malformed_icmp_pkt_too_big++; + return INVALID; + } + + return classify_icmp(skb, ipv4.protocol, &tuple, + sizeof(tuple.ipv4), metrics); +} + +static verdict_t process_icmpv6(struct bpf_dynptr *dynptr, __u64 *offset, struct __sk_buff *skb, + metrics_t *metrics) +{ + struct bpf_sock_tuple tuple; + struct ipv6hdr ipv6; + struct icmp6hdr icmp6; + bool is_fragment; + uint8_t l4_proto; + + if (bpf_dynptr_read(&icmp6, sizeof(icmp6), dynptr, *offset, 0)) { + metrics->errors_total_malformed_icmp++; + return INVALID; + } + + /* We should never receive encapsulated echo replies. */ + if (icmp6.icmp6_type == ICMPV6_ECHO_REPLY) { + metrics->errors_total_icmp_echo_replies++; + return INVALID; + } + + if (icmp6.icmp6_type == ICMPV6_ECHO_REQUEST) { + return ECHO_REQUEST; + } + + if (icmp6.icmp6_type != ICMPV6_PKT_TOOBIG) { + metrics->errors_total_unwanted_icmp++; + return INVALID; + } + + if (pkt_parse_ipv6(dynptr, offset, &ipv6, &l4_proto, &is_fragment)) { + metrics->errors_total_malformed_icmp_pkt_too_big++; + return INVALID; + } + + if (is_fragment) { + metrics->errors_total_fragmented_ip++; + return INVALID; + } + + /* Swap source and dest addresses. */ + memcpy(&tuple.ipv6.saddr, &ipv6.daddr, sizeof(tuple.ipv6.saddr)); + memcpy(&tuple.ipv6.daddr, &ipv6.saddr, sizeof(tuple.ipv6.daddr)); + + if (!pkt_parse_icmp_l4_ports(dynptr, offset, (flow_ports_t *)&tuple.ipv6.sport)) { + metrics->errors_total_malformed_icmp_pkt_too_big++; + return INVALID; + } + + return classify_icmp(skb, l4_proto, &tuple, sizeof(tuple.ipv6), + metrics); +} + +static verdict_t process_tcp(struct bpf_dynptr *dynptr, __u64 *offset, struct __sk_buff *skb, + struct iphdr_info *info, metrics_t *metrics) +{ + struct bpf_sock_tuple tuple; + struct tcphdr tcp; + uint64_t tuplen; + + metrics->l4_protocol_packets_total_tcp++; + + if (bpf_dynptr_read(&tcp, sizeof(tcp), dynptr, *offset, 0)) { + metrics->errors_total_malformed_tcp++; + return INVALID; + } + + *offset += sizeof(tcp); + + if (tcp.syn) + return SYN; + + tuplen = fill_tuple(&tuple, info->hdr, info->len, tcp.source, tcp.dest); + return classify_tcp(skb, &tuple, tuplen, info->hdr, &tcp); +} + +static verdict_t process_udp(struct bpf_dynptr *dynptr, __u64 *offset, struct __sk_buff *skb, + struct iphdr_info *info, metrics_t *metrics) +{ + struct bpf_sock_tuple tuple; + struct udphdr udph; + uint64_t tuplen; + + metrics->l4_protocol_packets_total_udp++; + + if (bpf_dynptr_read(&udph, sizeof(udph), dynptr, *offset, 0)) { + metrics->errors_total_malformed_udp++; + return INVALID; + } + *offset += sizeof(udph); + + tuplen = fill_tuple(&tuple, info->hdr, info->len, udph.source, udph.dest); + return classify_udp(skb, &tuple, tuplen); +} + +static verdict_t process_ipv4(struct __sk_buff *skb, struct bpf_dynptr *dynptr, + __u64 *offset, metrics_t *metrics) +{ + struct iphdr ipv4; + struct iphdr_info info = { + .hdr = &ipv4, + .len = sizeof(ipv4), + }; + + metrics->l3_protocol_packets_total_ipv4++; + + if (pkt_parse_ipv4(dynptr, offset, &ipv4)) { + metrics->errors_total_malformed_ip++; + return INVALID; + } + + if (ipv4.version != 4) { + metrics->errors_total_malformed_ip++; + return INVALID; + } + + if (ipv4_is_fragment(&ipv4)) { + metrics->errors_total_fragmented_ip++; + return INVALID; + } + + switch (ipv4.protocol) { + case IPPROTO_ICMP: + return process_icmpv4(skb, dynptr, offset, metrics); + + case IPPROTO_TCP: + return process_tcp(dynptr, offset, skb, &info, metrics); + + case IPPROTO_UDP: + return process_udp(dynptr, offset, skb, &info, metrics); + + default: + metrics->errors_total_unknown_l4_proto++; + return INVALID; + } +} + +static verdict_t process_ipv6(struct __sk_buff *skb, struct bpf_dynptr *dynptr, + __u64 *offset, metrics_t *metrics) +{ + struct ipv6hdr ipv6; + struct iphdr_info info = { + .hdr = &ipv6, + .len = sizeof(ipv6), + }; + uint8_t l4_proto; + bool is_fragment; + + metrics->l3_protocol_packets_total_ipv6++; + + if (pkt_parse_ipv6(dynptr, offset, &ipv6, &l4_proto, &is_fragment)) { + metrics->errors_total_malformed_ip++; + return INVALID; + } + + if (ipv6.version != 6) { + metrics->errors_total_malformed_ip++; + return INVALID; + } + + if (is_fragment) { + metrics->errors_total_fragmented_ip++; + return INVALID; + } + + switch (l4_proto) { + case IPPROTO_ICMPV6: + return process_icmpv6(dynptr, offset, skb, metrics); + + case IPPROTO_TCP: + return process_tcp(dynptr, offset, skb, &info, metrics); + + case IPPROTO_UDP: + return process_udp(dynptr, offset, skb, &info, metrics); + + default: + metrics->errors_total_unknown_l4_proto++; + return INVALID; + } +} + +SEC("tc") +int cls_redirect(struct __sk_buff *skb) +{ + struct bpf_dynptr dynptr; + struct in_addr next_hop; + /* Tracks offset of the dynptr. This will be unnecessary once + * bpf_dynptr_advance() is available. + */ + __u64 off = 0; + + bpf_dynptr_from_skb(skb, 0, &dynptr); + + metrics_t *metrics = get_global_metrics(); + if (metrics == NULL) + return TC_ACT_SHOT; + + metrics->processed_packets_total++; + + /* Pass bogus packets as long as we're not sure they're + * destined for us. + */ + if (skb->protocol != bpf_htons(ETH_P_IP)) + return TC_ACT_OK; + + encap_headers_t *encap; + + /* Make sure that all encapsulation headers are available in + * the linear portion of the skb. This makes it easy to manipulate them. + */ + if (bpf_skb_pull_data(skb, sizeof(*encap))) + return TC_ACT_OK; + + encap = bpf_dynptr_data(&dynptr, 0, sizeof(*encap)); + if (!encap) + return TC_ACT_OK; + + off += sizeof(*encap); + + if (encap->ip.ihl != 5) + /* We never have any options. */ + return TC_ACT_OK; + + if (encap->ip.daddr != ENCAPSULATION_IP || + encap->ip.protocol != IPPROTO_UDP) + return TC_ACT_OK; + + /* TODO Check UDP length? */ + if (encap->udp.dest != ENCAPSULATION_PORT) + return TC_ACT_OK; + + /* We now know that the packet is destined to us, we can + * drop bogus ones. + */ + if (ipv4_is_fragment((void *)&encap->ip)) { + metrics->errors_total_fragmented_ip++; + return TC_ACT_SHOT; + } + + if (encap->gue.variant != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + if (encap->gue.control != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + if (encap->gue.flags != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + if (encap->gue.hlen != + sizeof(encap->unigue) / 4 + encap->unigue.hop_count) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + if (encap->unigue.version != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + if (encap->unigue.reserved != 0) + return TC_ACT_SHOT; + + MAYBE_RETURN(get_next_hop(&dynptr, &off, encap, &next_hop)); + + if (next_hop.s_addr == 0) { + metrics->accepted_packets_total_last_hop++; + return accept_locally(skb, encap); + } + + verdict_t verdict; + switch (encap->gue.proto_ctype) { + case IPPROTO_IPIP: + verdict = process_ipv4(skb, &dynptr, &off, metrics); + break; + + case IPPROTO_IPV6: + verdict = process_ipv6(skb, &dynptr, &off, metrics); + break; + + default: + metrics->errors_total_unknown_l3_proto++; + return TC_ACT_SHOT; + } + + switch (verdict) { + case INVALID: + /* metrics have already been bumped */ + return TC_ACT_SHOT; + + case UNKNOWN: + return forward_to_next_hop(skb, &dynptr, encap, &next_hop, metrics); + + case ECHO_REQUEST: + metrics->accepted_packets_total_icmp_echo_request++; + break; + + case SYN: + if (encap->unigue.forward_syn) { + return forward_to_next_hop(skb, &dynptr, encap, &next_hop, + metrics); + } + + metrics->accepted_packets_total_syn++; + break; + + case SYN_COOKIE: + metrics->accepted_packets_total_syn_cookies++; + break; + + case ESTABLISHED: + metrics->accepted_packets_total_established++; + break; + } + + return accept_locally(skb, encap); +} diff --git a/tools/testing/selftests/bpf/progs/test_l4lb_noinline_dynptr.c b/tools/testing/selftests/bpf/progs/test_l4lb_noinline_dynptr.c new file mode 100644 index 000000000000..d7ff94d3ec1c --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_l4lb_noinline_dynptr.c @@ -0,0 +1,469 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2017 Facebook +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "test_iptunnel_common.h" +#include + +static __always_inline __u32 rol32(__u32 word, unsigned int shift) +{ + return (word << shift) | (word >> ((-shift) & 31)); +} + +/* copy paste of jhash from kernel sources to make sure llvm + * can compile it into valid sequence of bpf instructions + */ +#define __jhash_mix(a, b, c) \ +{ \ + a -= c; a ^= rol32(c, 4); c += b; \ + b -= a; b ^= rol32(a, 6); a += c; \ + c -= b; c ^= rol32(b, 8); b += a; \ + a -= c; a ^= rol32(c, 16); c += b; \ + b -= a; b ^= rol32(a, 19); a += c; \ + c -= b; c ^= rol32(b, 4); b += a; \ +} + +#define __jhash_final(a, b, c) \ +{ \ + c ^= b; c -= rol32(b, 14); \ + a ^= c; a -= rol32(c, 11); \ + b ^= a; b -= rol32(a, 25); \ + c ^= b; c -= rol32(b, 16); \ + a ^= c; a -= rol32(c, 4); \ + b ^= a; b -= rol32(a, 14); \ + c ^= b; c -= rol32(b, 24); \ +} + +#define JHASH_INITVAL 0xdeadbeef + +typedef unsigned int u32; + +static __noinline u32 jhash(const void *key, u32 length, u32 initval) +{ + u32 a, b, c; + const unsigned char *k = key; + + a = b = c = JHASH_INITVAL + length + initval; + + while (length > 12) { + a += *(u32 *)(k); + b += *(u32 *)(k + 4); + c += *(u32 *)(k + 8); + __jhash_mix(a, b, c); + length -= 12; + k += 12; + } + switch (length) { + case 12: c += (u32)k[11]<<24; + case 11: c += (u32)k[10]<<16; + case 10: c += (u32)k[9]<<8; + case 9: c += k[8]; + case 8: b += (u32)k[7]<<24; + case 7: b += (u32)k[6]<<16; + case 6: b += (u32)k[5]<<8; + case 5: b += k[4]; + case 4: a += (u32)k[3]<<24; + case 3: a += (u32)k[2]<<16; + case 2: a += (u32)k[1]<<8; + case 1: a += k[0]; + __jhash_final(a, b, c); + case 0: /* Nothing left to add */ + break; + } + + return c; +} + +static __noinline u32 __jhash_nwords(u32 a, u32 b, u32 c, u32 initval) +{ + a += initval; + b += initval; + c += initval; + __jhash_final(a, b, c); + return c; +} + +static __noinline u32 jhash_2words(u32 a, u32 b, u32 initval) +{ + return __jhash_nwords(a, b, 0, initval + JHASH_INITVAL + (2 << 2)); +} + +#define PCKT_FRAGMENTED 65343 +#define IPV4_HDR_LEN_NO_OPT 20 +#define IPV4_PLUS_ICMP_HDR 28 +#define IPV6_PLUS_ICMP_HDR 48 +#define RING_SIZE 2 +#define MAX_VIPS 12 +#define MAX_REALS 5 +#define CTL_MAP_SIZE 16 +#define CH_RINGS_SIZE (MAX_VIPS * RING_SIZE) +#define F_IPV6 (1 << 0) +#define F_HASH_NO_SRC_PORT (1 << 0) +#define F_ICMP (1 << 0) +#define F_SYN_SET (1 << 1) + +struct packet_description { + union { + __be32 src; + __be32 srcv6[4]; + }; + union { + __be32 dst; + __be32 dstv6[4]; + }; + union { + __u32 ports; + __u16 port16[2]; + }; + __u8 proto; + __u8 flags; +}; + +struct ctl_value { + union { + __u64 value; + __u32 ifindex; + __u8 mac[6]; + }; +}; + +struct vip_meta { + __u32 flags; + __u32 vip_num; +}; + +struct real_definition { + union { + __be32 dst; + __be32 dstv6[4]; + }; + __u8 flags; +}; + +struct vip_stats { + __u64 bytes; + __u64 pkts; +}; + +struct eth_hdr { + unsigned char eth_dest[ETH_ALEN]; + unsigned char eth_source[ETH_ALEN]; + unsigned short eth_proto; +}; + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(max_entries, MAX_VIPS); + __type(key, struct vip); + __type(value, struct vip_meta); +} vip_map SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, CH_RINGS_SIZE); + __type(key, __u32); + __type(value, __u32); +} ch_rings SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, MAX_REALS); + __type(key, __u32); + __type(value, struct real_definition); +} reals SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); + __uint(max_entries, MAX_VIPS); + __type(key, __u32); + __type(value, struct vip_stats); +} stats SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, CTL_MAP_SIZE); + __type(key, __u32); + __type(value, struct ctl_value); +} ctl_array SEC(".maps"); + +static __noinline __u32 get_packet_hash(struct packet_description *pckt, bool ipv6) +{ + if (ipv6) + return jhash_2words(jhash(pckt->srcv6, 16, MAX_VIPS), + pckt->ports, CH_RINGS_SIZE); + else + return jhash_2words(pckt->src, pckt->ports, CH_RINGS_SIZE); +} + +static __noinline bool get_packet_dst(struct real_definition **real, + struct packet_description *pckt, + struct vip_meta *vip_info, + bool is_ipv6) +{ + __u32 hash = get_packet_hash(pckt, is_ipv6); + __u32 key = RING_SIZE * vip_info->vip_num + hash % RING_SIZE; + __u32 *real_pos; + + if (hash != 0x358459b7 /* jhash of ipv4 packet */ && + hash != 0x2f4bc6bb /* jhash of ipv6 packet */) + return false; + + real_pos = bpf_map_lookup_elem(&ch_rings, &key); + if (!real_pos) + return false; + key = *real_pos; + *real = bpf_map_lookup_elem(&reals, &key); + if (!(*real)) + return false; + return true; +} + +static __noinline int parse_icmpv6(struct bpf_dynptr *skb_ptr, __u64 off, + struct packet_description *pckt) +{ + struct icmp6hdr *icmp_hdr; + struct ipv6hdr *ip6h; + + icmp_hdr = bpf_dynptr_data(skb_ptr, off, sizeof(*icmp_hdr)); + if (!icmp_hdr) + return TC_ACT_SHOT; + + if (icmp_hdr->icmp6_type != ICMPV6_PKT_TOOBIG) + return TC_ACT_OK; + off += sizeof(struct icmp6hdr); + ip6h = (struct ipv6hdr *)bpf_dynptr_data(skb_ptr, off, sizeof(*ip6h)); + if (!ip6h) + return TC_ACT_SHOT; + pckt->proto = ip6h->nexthdr; + pckt->flags |= F_ICMP; + memcpy(pckt->srcv6, ip6h->daddr.s6_addr32, 16); + memcpy(pckt->dstv6, ip6h->saddr.s6_addr32, 16); + return TC_ACT_UNSPEC; +} + +static __noinline int parse_icmp(struct bpf_dynptr *skb_ptr, __u64 off, + struct packet_description *pckt) +{ + struct icmphdr *icmp_hdr; + struct iphdr *iph; + + icmp_hdr = bpf_dynptr_data(skb_ptr, off, sizeof(*icmp_hdr)); + if (!icmp_hdr) + return TC_ACT_SHOT; + if (icmp_hdr->type != ICMP_DEST_UNREACH || + icmp_hdr->code != ICMP_FRAG_NEEDED) + return TC_ACT_OK; + off += sizeof(struct icmphdr); + iph = bpf_dynptr_data(skb_ptr, off, sizeof(*iph)); + if (!iph || iph->ihl != 5) + return TC_ACT_SHOT; + pckt->proto = iph->protocol; + pckt->flags |= F_ICMP; + pckt->src = iph->daddr; + pckt->dst = iph->saddr; + return TC_ACT_UNSPEC; +} + +static __noinline bool parse_udp(struct bpf_dynptr *skb_ptr, __u64 off, + struct packet_description *pckt) +{ + struct udphdr *udp; + + udp = bpf_dynptr_data(skb_ptr, off, sizeof(*udp)); + if (!udp) + return false; + + if (!(pckt->flags & F_ICMP)) { + pckt->port16[0] = udp->source; + pckt->port16[1] = udp->dest; + } else { + pckt->port16[0] = udp->dest; + pckt->port16[1] = udp->source; + } + return true; +} + +static __noinline bool parse_tcp(struct bpf_dynptr *skb_ptr, __u64 off, + struct packet_description *pckt) +{ + struct tcphdr *tcp; + + tcp = bpf_dynptr_data(skb_ptr, off, sizeof(*tcp)); + if (!tcp) + return false; + + if (tcp->syn) + pckt->flags |= F_SYN_SET; + + if (!(pckt->flags & F_ICMP)) { + pckt->port16[0] = tcp->source; + pckt->port16[1] = tcp->dest; + } else { + pckt->port16[0] = tcp->dest; + pckt->port16[1] = tcp->source; + } + return true; +} + +static __noinline int process_packet(struct bpf_dynptr *skb_ptr, + struct eth_hdr *eth, __u64 off, + bool is_ipv6, struct __sk_buff *skb) +{ + struct packet_description pckt = {}; + struct bpf_tunnel_key tkey = {}; + struct vip_stats *data_stats; + struct real_definition *dst; + struct vip_meta *vip_info; + struct ctl_value *cval; + __u32 v4_intf_pos = 1; + __u32 v6_intf_pos = 2; + struct ipv6hdr *ip6h; + struct vip vip = {}; + struct iphdr *iph; + int tun_flag = 0; + __u16 pkt_bytes; + __u64 iph_len; + __u32 ifindex; + __u8 protocol; + __u32 vip_num; + int action; + + tkey.tunnel_ttl = 64; + if (is_ipv6) { + ip6h = bpf_dynptr_data(skb_ptr, off, sizeof(*ip6h)); + if (!ip6h) + return TC_ACT_SHOT; + + iph_len = sizeof(struct ipv6hdr); + protocol = ip6h->nexthdr; + pckt.proto = protocol; + pkt_bytes = bpf_ntohs(ip6h->payload_len); + off += iph_len; + if (protocol == IPPROTO_FRAGMENT) { + return TC_ACT_SHOT; + } else if (protocol == IPPROTO_ICMPV6) { + action = parse_icmpv6(skb_ptr, off, &pckt); + if (action >= 0) + return action; + off += IPV6_PLUS_ICMP_HDR; + } else { + memcpy(pckt.srcv6, ip6h->saddr.s6_addr32, 16); + memcpy(pckt.dstv6, ip6h->daddr.s6_addr32, 16); + } + } else { + iph = bpf_dynptr_data(skb_ptr, off, sizeof(*iph)); + if (!iph || iph->ihl != 5) + return TC_ACT_SHOT; + + protocol = iph->protocol; + pckt.proto = protocol; + pkt_bytes = bpf_ntohs(iph->tot_len); + off += IPV4_HDR_LEN_NO_OPT; + + if (iph->frag_off & PCKT_FRAGMENTED) + return TC_ACT_SHOT; + if (protocol == IPPROTO_ICMP) { + action = parse_icmp(skb_ptr, off, &pckt); + if (action >= 0) + return action; + off += IPV4_PLUS_ICMP_HDR; + } else { + pckt.src = iph->saddr; + pckt.dst = iph->daddr; + } + } + protocol = pckt.proto; + + if (protocol == IPPROTO_TCP) { + if (!parse_tcp(skb_ptr, off, &pckt)) + return TC_ACT_SHOT; + } else if (protocol == IPPROTO_UDP) { + if (!parse_udp(skb_ptr, off, &pckt)) + return TC_ACT_SHOT; + } else { + return TC_ACT_SHOT; + } + + if (is_ipv6) + memcpy(vip.daddr.v6, pckt.dstv6, 16); + else + vip.daddr.v4 = pckt.dst; + + vip.dport = pckt.port16[1]; + vip.protocol = pckt.proto; + vip_info = bpf_map_lookup_elem(&vip_map, &vip); + if (!vip_info) { + vip.dport = 0; + vip_info = bpf_map_lookup_elem(&vip_map, &vip); + if (!vip_info) + return TC_ACT_SHOT; + pckt.port16[1] = 0; + } + + if (vip_info->flags & F_HASH_NO_SRC_PORT) + pckt.port16[0] = 0; + + if (!get_packet_dst(&dst, &pckt, vip_info, is_ipv6)) + return TC_ACT_SHOT; + + if (dst->flags & F_IPV6) { + cval = bpf_map_lookup_elem(&ctl_array, &v6_intf_pos); + if (!cval) + return TC_ACT_SHOT; + ifindex = cval->ifindex; + memcpy(tkey.remote_ipv6, dst->dstv6, 16); + tun_flag = BPF_F_TUNINFO_IPV6; + } else { + cval = bpf_map_lookup_elem(&ctl_array, &v4_intf_pos); + if (!cval) + return TC_ACT_SHOT; + ifindex = cval->ifindex; + tkey.remote_ipv4 = dst->dst; + } + vip_num = vip_info->vip_num; + data_stats = bpf_map_lookup_elem(&stats, &vip_num); + if (!data_stats) + return TC_ACT_SHOT; + data_stats->pkts++; + data_stats->bytes += pkt_bytes; + bpf_skb_set_tunnel_key(skb, &tkey, sizeof(tkey), tun_flag); + *(u32 *)eth->eth_dest = tkey.remote_ipv4; + return bpf_redirect(ifindex, 0); +} + +SEC("tc") +int balancer_ingress(struct __sk_buff *ctx) +{ + struct bpf_dynptr ptr; + struct eth_hdr *eth; + __u32 eth_proto; + __u32 nh_off; + + nh_off = sizeof(struct eth_hdr); + + bpf_dynptr_from_skb(ctx, 0, &ptr); + eth = bpf_dynptr_data(&ptr, 0, sizeof(*eth)); + if (!eth) + return TC_ACT_SHOT; + eth_proto = eth->eth_proto; + if (eth_proto == bpf_htons(ETH_P_IP)) + return process_packet(&ptr, eth, nh_off, false, ctx); + else if (eth_proto == bpf_htons(ETH_P_IPV6)) + return process_packet(&ptr, eth, nh_off, true, ctx); + else + return TC_ACT_SHOT; +} + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt.c b/tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt.c new file mode 100644 index 000000000000..79bab9b50e9e --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt.c @@ -0,0 +1,119 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* This parsing logic is taken from the open source library katran, a layer 4 + * load balancer. + * + * This code logic using dynptrs can be found in test_parse_tcp_hdr_opt_dynptr.c + * + * https://github.com/facebookincubator/katran/blob/main/katran/lib/bpf/pckt_parsing.h + */ + +#include +#include +#include +#include +#include +#include +#include "test_tcp_hdr_options.h" + +char _license[] SEC("license") = "GPL"; + +/* Kind number used for experiments */ +const __u32 tcp_hdr_opt_kind_tpr = 0xFD; +/* Length of the tcp header option */ +const __u32 tcp_hdr_opt_len_tpr = 6; +/* maximum number of header options to check to lookup server_id */ +const __u32 tcp_hdr_opt_max_opt_checks = 15; + +__u32 server_id; + +struct hdr_opt_state { + __u32 server_id; + __u8 byte_offset; + __u8 hdr_bytes_remaining; +}; + +static int parse_hdr_opt(const struct xdp_md *xdp, struct hdr_opt_state *state) +{ + const void *data = (void *)(long)xdp->data; + const void *data_end = (void *)(long)xdp->data_end; + __u8 *tcp_opt, kind, hdr_len; + + tcp_opt = (__u8 *)(data + state->byte_offset); + if (tcp_opt + 1 > data_end) + return -1; + + kind = tcp_opt[0]; + + if (kind == TCPOPT_EOL) + return -1; + + if (kind == TCPOPT_NOP) { + state->hdr_bytes_remaining--; + state->byte_offset++; + return 0; + } + + if (state->hdr_bytes_remaining < 2 || + tcp_opt + sizeof(__u8) + sizeof(__u8) > data_end) + return -1; + + hdr_len = tcp_opt[1]; + if (hdr_len > state->hdr_bytes_remaining) + return -1; + + if (kind == tcp_hdr_opt_kind_tpr) { + if (hdr_len != tcp_hdr_opt_len_tpr) + return -1; + + if (tcp_opt + tcp_hdr_opt_len_tpr > data_end) + return -1; + + state->server_id = *(__u32 *)&tcp_opt[2]; + return 1; + } + + state->hdr_bytes_remaining -= hdr_len; + state->byte_offset += hdr_len; + return 0; +} + +SEC("xdp") +int xdp_ingress_v6(struct xdp_md *xdp) +{ + const void *data = (void *)(long)xdp->data; + const void *data_end = (void *)(long)xdp->data_end; + struct hdr_opt_state opt_state = {}; + __u8 tcp_hdr_opt_len = 0; + struct tcphdr *tcp_hdr; + __u64 tcp_offset = 0; + __u32 off; + int err; + + tcp_offset = sizeof(struct ethhdr) + sizeof(struct ipv6hdr); + tcp_hdr = (struct tcphdr *)(data + tcp_offset); + if (tcp_hdr + 1 > data_end) + return XDP_DROP; + + tcp_hdr_opt_len = (tcp_hdr->doff * 4) - sizeof(struct tcphdr); + if (tcp_hdr_opt_len < tcp_hdr_opt_len_tpr) + return XDP_DROP; + + opt_state.hdr_bytes_remaining = tcp_hdr_opt_len; + opt_state.byte_offset = sizeof(struct tcphdr) + tcp_offset; + + /* max number of bytes of options in tcp header is 40 bytes */ + for (int i = 0; i < tcp_hdr_opt_max_opt_checks; i++) { + err = parse_hdr_opt(xdp, &opt_state); + + if (err || !opt_state.hdr_bytes_remaining) + break; + } + + if (!opt_state.server_id) + return XDP_DROP; + + server_id = opt_state.server_id; + + return XDP_PASS; +} diff --git a/tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt_dynptr.c b/tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt_dynptr.c new file mode 100644 index 000000000000..0b97a6708fc5 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt_dynptr.c @@ -0,0 +1,110 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* This logic is lifted from a real-world use case of packet parsing, used in + * the open source library katran, a layer 4 load balancer. + * + * This test demonstrates how to parse packet contents using dynptrs. The + * original code (parsing without dynptrs) can be found in test_parse_tcp_hdr_opt.c + */ + +#include +#include +#include +#include +#include +#include +#include "test_tcp_hdr_options.h" + +char _license[] SEC("license") = "GPL"; + +/* Kind number used for experiments */ +const __u32 tcp_hdr_opt_kind_tpr = 0xFD; +/* Length of the tcp header option */ +const __u32 tcp_hdr_opt_len_tpr = 6; +/* maximum number of header options to check to lookup server_id */ +const __u32 tcp_hdr_opt_max_opt_checks = 15; + +__u32 server_id; + +static int parse_hdr_opt(struct bpf_dynptr *ptr, __u32 *off, __u8 *hdr_bytes_remaining, + __u32 *server_id) +{ + __u8 *tcp_opt, kind, hdr_len; + __u8 *data; + + data = bpf_dynptr_data(ptr, *off, sizeof(kind) + sizeof(hdr_len) + + sizeof(*server_id)); + if (!data) + return -1; + + kind = data[0]; + + if (kind == TCPOPT_EOL) + return -1; + + if (kind == TCPOPT_NOP) { + *off += 1; + *hdr_bytes_remaining -= 1; + return 0; + } + + if (*hdr_bytes_remaining < 2) + return -1; + + hdr_len = data[1]; + if (hdr_len > *hdr_bytes_remaining) + return -1; + + if (kind == tcp_hdr_opt_kind_tpr) { + if (hdr_len != tcp_hdr_opt_len_tpr) + return -1; + + __builtin_memcpy(server_id, (__u32 *)(data + 2), sizeof(*server_id)); + return 1; + } + + *off += hdr_len; + *hdr_bytes_remaining -= hdr_len; + return 0; +} + +SEC("xdp") +int xdp_ingress_v6(struct xdp_md *xdp) +{ + __u8 hdr_bytes_remaining; + struct tcphdr *tcp_hdr; + __u8 tcp_hdr_opt_len; + int err = 0; + __u32 off; + + struct bpf_dynptr ptr; + + bpf_dynptr_from_xdp(xdp, 0, &ptr); + + off = sizeof(struct ethhdr) + sizeof(struct ipv6hdr); + + tcp_hdr = bpf_dynptr_data(&ptr, off, sizeof(*tcp_hdr)); + if (!tcp_hdr) + return XDP_DROP; + + tcp_hdr_opt_len = (tcp_hdr->doff * 4) - sizeof(struct tcphdr); + if (tcp_hdr_opt_len < tcp_hdr_opt_len_tpr) + return XDP_DROP; + + hdr_bytes_remaining = tcp_hdr_opt_len; + + off += sizeof(struct tcphdr); + + /* max number of bytes of options in tcp header is 40 bytes */ + for (int i = 0; i < tcp_hdr_opt_max_opt_checks; i++) { + err = parse_hdr_opt(&ptr, &off, &hdr_bytes_remaining, &server_id); + + if (err || !hdr_bytes_remaining) + break; + } + + if (!server_id) + return XDP_DROP; + + return XDP_PASS; +} diff --git a/tools/testing/selftests/bpf/progs/test_xdp_dynptr.c b/tools/testing/selftests/bpf/progs/test_xdp_dynptr.c new file mode 100644 index 000000000000..bcc4daefd559 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_xdp_dynptr.c @@ -0,0 +1,235 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "test_iptunnel_common.h" + +const size_t tcphdr_sz = sizeof(struct tcphdr); +const size_t udphdr_sz = sizeof(struct udphdr); +const size_t ethhdr_sz = sizeof(struct ethhdr); +const size_t iphdr_sz = sizeof(struct iphdr); +const size_t ipv6hdr_sz = sizeof(struct ipv6hdr); + +struct { + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); + __uint(max_entries, 256); + __type(key, __u32); + __type(value, __u64); +} rxcnt SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(max_entries, MAX_IPTNL_ENTRIES); + __type(key, struct vip); + __type(value, struct iptnl_info); +} vip2tnl SEC(".maps"); + +static __always_inline void count_tx(__u32 protocol) +{ + __u64 *rxcnt_count; + + rxcnt_count = bpf_map_lookup_elem(&rxcnt, &protocol); + if (rxcnt_count) + *rxcnt_count += 1; +} + +static __always_inline int get_dport(void *trans_data, __u8 protocol) +{ + struct tcphdr *th; + struct udphdr *uh; + + switch (protocol) { + case IPPROTO_TCP: + th = (struct tcphdr *)trans_data; + return th->dest; + case IPPROTO_UDP: + uh = (struct udphdr *)trans_data; + return uh->dest; + default: + return 0; + } +} + +static __always_inline void set_ethhdr(struct ethhdr *new_eth, + const struct ethhdr *old_eth, + const struct iptnl_info *tnl, + __be16 h_proto) +{ + memcpy(new_eth->h_source, old_eth->h_dest, sizeof(new_eth->h_source)); + memcpy(new_eth->h_dest, tnl->dmac, sizeof(new_eth->h_dest)); + new_eth->h_proto = h_proto; +} + +static __always_inline int handle_ipv4(struct xdp_md *xdp, struct bpf_dynptr *xdp_ptr) +{ + struct bpf_dynptr new_xdp_ptr; + struct iptnl_info *tnl; + struct ethhdr *new_eth; + struct ethhdr *old_eth; + __u32 transport_hdr_sz; + struct iphdr *iph; + __u16 *next_iph; + __u16 payload_len; + struct vip vip = {}; + int dport; + __u32 csum = 0; + int i; + + if (ethhdr_sz + iphdr_sz + tcphdr_sz > xdp->data_end - xdp->data) + transport_hdr_sz = udphdr_sz; + else + transport_hdr_sz = tcphdr_sz; + + iph = bpf_dynptr_data(xdp_ptr, ethhdr_sz, iphdr_sz + transport_hdr_sz); + if (!iph) + return XDP_DROP; + + dport = get_dport(iph + 1, iph->protocol); + if (dport == -1) + return XDP_DROP; + + vip.protocol = iph->protocol; + vip.family = AF_INET; + vip.daddr.v4 = iph->daddr; + vip.dport = dport; + payload_len = bpf_ntohs(iph->tot_len); + + tnl = bpf_map_lookup_elem(&vip2tnl, &vip); + /* It only does v4-in-v4 */ + if (!tnl || tnl->family != AF_INET) + return XDP_PASS; + + if (bpf_xdp_adjust_head(xdp, 0 - (int)iphdr_sz)) + return XDP_DROP; + + bpf_dynptr_from_xdp(xdp, 0, &new_xdp_ptr); + new_eth = bpf_dynptr_data(&new_xdp_ptr, 0, ethhdr_sz + iphdr_sz + ethhdr_sz); + if (!new_eth) + return XDP_DROP; + + iph = (struct iphdr *)(new_eth + 1); + old_eth = (struct ethhdr *)(iph + 1); + + set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IP)); + + iph->version = 4; + iph->ihl = iphdr_sz >> 2; + iph->frag_off = 0; + iph->protocol = IPPROTO_IPIP; + iph->check = 0; + iph->tos = 0; + iph->tot_len = bpf_htons(payload_len + iphdr_sz); + iph->daddr = tnl->daddr.v4; + iph->saddr = tnl->saddr.v4; + iph->ttl = 8; + + next_iph = (__u16 *)iph; + for (i = 0; i < iphdr_sz >> 1; i++) + csum += *next_iph++; + + iph->check = ~((csum & 0xffff) + (csum >> 16)); + + count_tx(vip.protocol); + + return XDP_TX; +} + +static __always_inline int handle_ipv6(struct xdp_md *xdp, struct bpf_dynptr *xdp_ptr) +{ + struct bpf_dynptr new_xdp_ptr; + struct iptnl_info *tnl; + struct ethhdr *new_eth; + struct ethhdr *old_eth; + __u32 transport_hdr_sz; + struct ipv6hdr *ip6h; + __u16 payload_len; + struct vip vip = {}; + int dport; + + if (ethhdr_sz + iphdr_sz + tcphdr_sz > xdp->data_end - xdp->data) + transport_hdr_sz = udphdr_sz; + else + transport_hdr_sz = tcphdr_sz; + + ip6h = bpf_dynptr_data(xdp_ptr, ethhdr_sz, ipv6hdr_sz + transport_hdr_sz); + if (!ip6h) + return XDP_DROP; + + dport = get_dport(ip6h + 1, ip6h->nexthdr); + if (dport == -1) + return XDP_DROP; + + vip.protocol = ip6h->nexthdr; + vip.family = AF_INET6; + memcpy(vip.daddr.v6, ip6h->daddr.s6_addr32, sizeof(vip.daddr)); + vip.dport = dport; + payload_len = ip6h->payload_len; + + tnl = bpf_map_lookup_elem(&vip2tnl, &vip); + /* It only does v6-in-v6 */ + if (!tnl || tnl->family != AF_INET6) + return XDP_PASS; + + if (bpf_xdp_adjust_head(xdp, 0 - (int)ipv6hdr_sz)) + return XDP_DROP; + + bpf_dynptr_from_xdp(xdp, 0, &new_xdp_ptr); + new_eth = bpf_dynptr_data(&new_xdp_ptr, 0, ethhdr_sz + ipv6hdr_sz + ethhdr_sz); + if (!new_eth) + return XDP_DROP; + + ip6h = (struct ipv6hdr *)(new_eth + 1); + old_eth = (struct ethhdr *)(ip6h + 1); + + set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IPV6)); + + ip6h->version = 6; + ip6h->priority = 0; + memset(ip6h->flow_lbl, 0, sizeof(ip6h->flow_lbl)); + ip6h->payload_len = bpf_htons(bpf_ntohs(payload_len) + ipv6hdr_sz); + ip6h->nexthdr = IPPROTO_IPV6; + ip6h->hop_limit = 8; + memcpy(ip6h->saddr.s6_addr32, tnl->saddr.v6, sizeof(tnl->saddr.v6)); + memcpy(ip6h->daddr.s6_addr32, tnl->daddr.v6, sizeof(tnl->daddr.v6)); + + count_tx(vip.protocol); + + return XDP_TX; +} + +SEC("xdp") +int _xdp_tx_iptunnel(struct xdp_md *xdp) +{ + struct bpf_dynptr ptr; + struct ethhdr *eth; + __u16 h_proto; + + bpf_dynptr_from_xdp(xdp, 0, &ptr); + eth = bpf_dynptr_data(&ptr, 0, ethhdr_sz); + if (!eth) + return XDP_DROP; + + h_proto = eth->h_proto; + + if (h_proto == bpf_htons(ETH_P_IP)) + return handle_ipv4(xdp, &ptr); + else if (h_proto == bpf_htons(ETH_P_IPV6)) + + return handle_ipv6(xdp, &ptr); + else + return XDP_DROP; +} + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/test_tcp_hdr_options.h b/tools/testing/selftests/bpf/test_tcp_hdr_options.h index 6118e3ab61fc..56c9f8a3ad3d 100644 --- a/tools/testing/selftests/bpf/test_tcp_hdr_options.h +++ b/tools/testing/selftests/bpf/test_tcp_hdr_options.h @@ -50,6 +50,7 @@ struct linum_err { #define TCPOPT_EOL 0 #define TCPOPT_NOP 1 +#define TCPOPT_MSS 2 #define TCPOPT_WINDOW 3 #define TCPOPT_EXP 254