@@ -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();
}
@@ -2,20 +2,29 @@
/* Copyright (c) 2022 Facebook */
#include <test_progs.h>
+#include <network_helpers.h>
#include "dynptr_fail.skel.h"
#include "dynptr_success.skel.h"
+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[] = {
/* success cases */
- {"test_read_write", NULL},
- {"test_data_slice", NULL},
- {"test_ringbuf", NULL},
+ {"test_read_write", SETUP_SYSCALL_SLEEP},
+ {"test_data_slice", SETUP_SYSCALL_SLEEP},
+ {"test_ringbuf", SETUP_SYSCALL_SLEEP},
+ {"test_skb_readonly", SETUP_SKB_PROG},
};
-static void verify_success(const char *prog_name)
+static void verify_success(const char *prog_name, enum test_setup_type setup_type)
{
struct dynptr_success *skel;
struct bpf_program *prog;
@@ -35,15 +44,45 @@ 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);
@@ -57,7 +96,7 @@ void test_dynptr(void)
if (!test__start_subtest(dynptr_tests[i].prog_name))
continue;
- verify_success(dynptr_tests[i].prog_name);
+ verify_success(dynptr_tests[i].prog_name, dynptr_tests[i].type);
}
RUN_TESTS(dynptr_fail);
@@ -93,4 +93,6 @@ void test_l4lb_all(void)
test_l4lb("test_l4lb.bpf.o");
if (test__start_subtest("l4lb_noinline"))
test_l4lb("test_l4lb_noinline.bpf.o");
+ if (test__start_subtest("l4lb_noinline_dynptr"))
+ test_l4lb("test_l4lb_noinline_dynptr.bpf.o");
}
new file mode 100644
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <test_progs.h>
+#include <network_helpers.h>
+#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();
+}
@@ -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.bpf.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.bpf.o");
+ if (test__start_subtest("xdp_attach_dynptr"))
+ serial_test_xdp_attach("./test_xdp_dynptr.bpf.o");
+}
@@ -5,10 +5,18 @@
#include <string.h>
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
+#include <linux/if_ether.h>
#include "bpf_misc.h"
char _license[] SEC("license") = "GPL";
+extern int bpf_dynptr_from_skb(struct __sk_buff *skb, __u64 flags,
+ struct bpf_dynptr *ptr, int rd_only) __ksym;
+extern int bpf_dynptr_from_xdp(struct xdp_md *xdp, __u64 flags,
+ struct bpf_dynptr *ptr) __ksym;
+
+#define bpf_dynptr_from_skb(skb, flags, ptr) bpf_dynptr_from_skb(skb, flags, ptr, 0)
+
struct test_info {
int x;
struct bpf_dynptr ptr;
@@ -1044,6 +1052,89 @@ int dynptr_read_into_slot(void *ctx)
return 0;
}
+/* The data slice is invalidated whenever a helper changes packet data */
+SEC("?tc")
+__failure __msg("invalid mem access 'scalar'")
+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")
+__failure __msg("invalid mem access 'scalar'")
+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")
+__failure __msg("invalid mem access 'scalar'")
+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")
+__failure __msg("calling kernel function bpf_dynptr_from_skb is not allowed")
+int skb_invalid_ctx(void *ctx)
+{
+ struct bpf_dynptr ptr;
+
+ /* this should fail */
+ bpf_dynptr_from_skb(ctx, 0, &ptr);
+
+ return 0;
+}
+
/* Reject writes to dynptr slot for uninit arg */
SEC("?raw_tp")
__failure __msg("potential write to dynptr at off=-16")
@@ -1061,6 +1152,19 @@ int uninit_write_into_slot(void *ctx)
return 0;
}
+/* Only supported prog type can create xdp-type dynptrs */
+SEC("?raw_tp")
+__failure __msg("calling kernel function bpf_dynptr_from_xdp is not allowed")
+int xdp_invalid_ctx(void *ctx)
+{
+ struct bpf_dynptr ptr;
+
+ /* this should fail */
+ bpf_dynptr_from_xdp(ctx, 0, &ptr);
+
+ return 0;
+}
+
static int callback(__u32 index, void *data)
{
*(__u32 *)data = 123;
@@ -1092,3 +1196,23 @@ int invalid_data_slices(void *ctx)
return 0;
}
+
+/* Read-only skb packet buffers can't be written to through data slices */
+SEC("?cgroup_skb/egress")
+__failure __msg("cannot write into rdonly_mem")
+int skb_invalid_write(struct __sk_buff *skb)
+{
+ struct bpf_dynptr ptr;
+ __u64 *data;
+
+ bpf_dynptr_from_skb(skb, 0, &ptr);
+
+ data = bpf_dynptr_data(&ptr, 0, sizeof(*data));
+ if (!data)
+ return 0;
+
+ /* this should fail */
+ *data = 123;
+
+ return 0;
+}
@@ -9,6 +9,11 @@
char _license[] SEC("license") = "GPL";
+extern int bpf_dynptr_from_skb(struct __sk_buff *skb, __u64 flags,
+ struct bpf_dynptr *ptr, int rd_only) __ksym;
+
+#define bpf_dynptr_from_skb(skb, flags, ptr) bpf_dynptr_from_skb(skb, flags, ptr, 0)
+
int pid, err, val;
struct sample {
@@ -163,3 +168,26 @@ 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;
+ }
+
+ /* 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 = 2;
+ return 0;
+ }
+
+ return 0;
+}
new file mode 100644
@@ -0,0 +1,973 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+// Copyright (c) 2019, 2020 Cloudflare
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <linux/bpf.h>
+#include <linux/icmp.h>
+#include <linux/icmpv6.h>
+#include <linux/if_ether.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/pkt_cls.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+
+#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";
+
+extern int bpf_dynptr_from_skb(struct __sk_buff *skb, __u64 flags,
+ struct bpf_dynptr *ptr, int rd_only) __ksym;
+
+#define bpf_dynptr_from_skb(skb, flags, ptr) bpf_dynptr_from_skb(skb, flags, ptr, 0)
+
+/**
+ * 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);
+}
new file mode 100644
@@ -0,0 +1,474 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2017 Facebook
+#include <stddef.h>
+#include <stdbool.h>
+#include <string.h>
+#include <linux/pkt_cls.h>
+#include <linux/bpf.h>
+#include <linux/in.h>
+#include <linux/if_ether.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/icmp.h>
+#include <linux/icmpv6.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <bpf/bpf_helpers.h>
+#include "test_iptunnel_common.h"
+#include <bpf/bpf_endian.h>
+
+extern int bpf_dynptr_from_skb(struct __sk_buff *skb, __u64 flags,
+ struct bpf_dynptr *ptr, int rd_only) __ksym;
+
+#define bpf_dynptr_from_skb(skb, flags, ptr) bpf_dynptr_from_skb(skb, flags, ptr, 0)
+
+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";
new file mode 100644
@@ -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 <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <linux/tcp.h>
+#include <stdbool.h>
+#include <linux/ipv6.h>
+#include <linux/if_ether.h>
+#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;
+}
new file mode 100644
@@ -0,0 +1,112 @@
+// 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 <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <linux/tcp.h>
+#include <stdbool.h>
+#include <linux/ipv6.h>
+#include <linux/if_ether.h>
+#include "test_tcp_hdr_options.h"
+
+char _license[] SEC("license") = "GPL";
+
+extern int bpf_dynptr_from_xdp(struct xdp_md *xdp, __u64 flags, struct bpf_dynptr *ptr) __ksym;
+
+/* 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;
+}
new file mode 100644
@@ -0,0 +1,237 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta */
+#include <stddef.h>
+#include <string.h>
+#include <linux/bpf.h>
+#include <linux/if_ether.h>
+#include <linux/if_packet.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/in.h>
+#include <linux/udp.h>
+#include <linux/tcp.h>
+#include <linux/pkt_cls.h>
+#include <sys/socket.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+#include "test_iptunnel_common.h"
+
+extern int bpf_dynptr_from_xdp(struct xdp_md *xdp, __u64 flags, struct bpf_dynptr *ptr) __ksym;
+
+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";
@@ -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
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. 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"): original version: 0.092 sec with dynptrs: 0.078 sec 2) progs/test_xdp_dynptr.c * Rewrite "progs/test_xdp.c" test to use dynptrs to parse xdp data 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 xdp_attach"): original version: 0.118 sec with dynptrs: 0.094 sec 3) progs/test_l4lb_noinline_dynptr.c * Rewrite "progs/test_l4lb_noinline.c" test to use dynptrs to parse skb data 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 l4lb_all"): original version: 0.062 sec with dynptrs: 0.081 sec For number of processed verifier instructions: original version: 6268 insns with dynptrs: 2588 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. 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 parse_tcp_hdr_opt"): original version: 0.031 sec with dynptrs: 0.045 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. * Add test case "skb_invalid_write" for testing that writes to a read-only data slice are rejected by the verifier. [0] https://github.com/facebookincubator/katran/blob/main/katran/lib/bpf/pckt_parsing.h Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> --- .../selftests/bpf/prog_tests/cls_redirect.c | 25 + .../testing/selftests/bpf/prog_tests/dynptr.c | 63 +- .../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 | 124 +++ .../selftests/bpf/progs/dynptr_success.c | 28 + .../bpf/progs/test_cls_redirect_dynptr.c | 973 ++++++++++++++++++ .../bpf/progs/test_l4lb_noinline_dynptr.c | 474 +++++++++ .../bpf/progs/test_parse_tcp_hdr_opt.c | 119 +++ .../bpf/progs/test_parse_tcp_hdr_opt_dynptr.c | 112 ++ .../selftests/bpf/progs/test_xdp_dynptr.c | 237 +++++ .../selftests/bpf/test_tcp_hdr_options.h | 1 + 13 files changed, 2248 insertions(+), 14 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