Merge branch 'cloudflare-prog'

Lorenz Bauer says:

====================
We've been developing an in-house L4 load balancer based on XDP
and TC for a while. Following Alexei's call for more up-to-date examples of
production BPF in the kernel tree [1], Cloudflare is making this available
under dual GPL-2.0 or BSD 3-clause terms.

The code requires at least v5.3 to function correctly.

1: https://lore.kernel.org/bpf/20200326210719.den5isqxntnoqhmv@ast-mbp/
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/prog_tests/cls_redirect.c

+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+// Copyright (c) 2020 Cloudflare
+
+#define _GNU_SOURCE
+
+#include <arpa/inet.h>
+#include <string.h>
+
+#include <linux/pkt_cls.h>
+
+#include <test_progs.h>
+
+#include "progs/test_cls_redirect.h"
+#include "test_cls_redirect.skel.h"
+
+#define ENCAP_IP INADDR_LOOPBACK
+#define ENCAP_PORT (1234)
+
+struct addr_port {
+	in_port_t port;
+	union {
+		struct in_addr in_addr;
+		struct in6_addr in6_addr;
+	};
+};
+
+struct tuple {
+	int family;
+	struct addr_port src;
+	struct addr_port dst;
+};
+
+static int start_server(const struct sockaddr *addr, socklen_t len, int type)
+{
+	int fd = socket(addr->sa_family, type, 0);
+	if (CHECK_FAIL(fd == -1))
+		return -1;
+	if (CHECK_FAIL(bind(fd, addr, len) == -1))
+		goto err;
+	if (type == SOCK_STREAM && CHECK_FAIL(listen(fd, 128) == -1))
+		goto err;
+
+	return fd;
+
+err:
+	close(fd);
+	return -1;
+}
+
+static int connect_to_server(const struct sockaddr *addr, socklen_t len,
+			     int type)
+{
+	int fd = socket(addr->sa_family, type, 0);
+	if (CHECK_FAIL(fd == -1))
+		return -1;
+	if (CHECK_FAIL(connect(fd, addr, len)))
+		goto err;
+
+	return fd;
+
+err:
+	close(fd);
+	return -1;
+}
+
+static bool fill_addr_port(const struct sockaddr *sa, struct addr_port *ap)
+{
+	const struct sockaddr_in6 *in6;
+	const struct sockaddr_in *in;
+
+	switch (sa->sa_family) {
+	case AF_INET:
+		in = (const struct sockaddr_in *)sa;
+		ap->in_addr = in->sin_addr;
+		ap->port = in->sin_port;
+		return true;
+
+	case AF_INET6:
+		in6 = (const struct sockaddr_in6 *)sa;
+		ap->in6_addr = in6->sin6_addr;
+		ap->port = in6->sin6_port;
+		return true;
+
+	default:
+		return false;
+	}
+}
+
+static bool set_up_conn(const struct sockaddr *addr, socklen_t len, int type,
+			int *server, int *conn, struct tuple *tuple)
+{
+	struct sockaddr_storage ss;
+	socklen_t slen = sizeof(ss);
+	struct sockaddr *sa = (struct sockaddr *)&ss;
+
+	*server = start_server(addr, len, type);
+	if (*server < 0)
+		return false;
+
+	if (CHECK_FAIL(getsockname(*server, sa, &slen)))
+		goto close_server;
+
+	*conn = connect_to_server(sa, slen, type);
+	if (*conn < 0)
+		goto close_server;
+
+	/* We want to simulate packets arriving at conn, so we have to
+	 * swap src and dst.
+	 */
+	slen = sizeof(ss);
+	if (CHECK_FAIL(getsockname(*conn, sa, &slen)))
+		goto close_conn;
+
+	if (CHECK_FAIL(!fill_addr_port(sa, &tuple->dst)))
+		goto close_conn;
+
+	slen = sizeof(ss);
+	if (CHECK_FAIL(getpeername(*conn, sa, &slen)))
+		goto close_conn;
+
+	if (CHECK_FAIL(!fill_addr_port(sa, &tuple->src)))
+		goto close_conn;
+
+	tuple->family = ss.ss_family;
+	return true;
+
+close_conn:
+	close(*conn);
+	*conn = -1;
+close_server:
+	close(*server);
+	*server = -1;
+	return false;
+}
+
+static socklen_t prepare_addr(struct sockaddr_storage *addr, int family)
+{
+	struct sockaddr_in *addr4;
+	struct sockaddr_in6 *addr6;
+
+	switch (family) {
+	case AF_INET:
+		addr4 = (struct sockaddr_in *)addr;
+		memset(addr4, 0, sizeof(*addr4));
+		addr4->sin_family = family;
+		addr4->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+		return sizeof(*addr4);
+	case AF_INET6:
+		addr6 = (struct sockaddr_in6 *)addr;
+		memset(addr6, 0, sizeof(*addr6));
+		addr6->sin6_family = family;
+		addr6->sin6_addr = in6addr_loopback;
+		return sizeof(*addr6);
+	default:
+		fprintf(stderr, "Invalid family %d", family);
+		return 0;
+	}
+}
+
+static bool was_decapsulated(struct bpf_prog_test_run_attr *tattr)
+{
+	return tattr->data_size_out < tattr->data_size_in;
+}
+
+enum type {
+	UDP,
+	TCP,
+	__NR_KIND,
+};
+
+enum hops {
+	NO_HOPS,
+	ONE_HOP,
+};
+
+enum flags {
+	NONE,
+	SYN,
+	ACK,
+};
+
+enum conn {
+	KNOWN_CONN,
+	UNKNOWN_CONN,
+};
+
+enum result {
+	ACCEPT,
+	FORWARD,
+};
+
+struct test_cfg {
+	enum type type;
+	enum result result;
+	enum conn conn;
+	enum hops hops;
+	enum flags flags;
+};
+
+static int test_str(void *buf, size_t len, const struct test_cfg *test,
+		    int family)
+{
+	const char *family_str, *type, *conn, *hops, *result, *flags;
+
+	family_str = "IPv4";
+	if (family == AF_INET6)
+		family_str = "IPv6";
+
+	type = "TCP";
+	if (test->type == UDP)
+		type = "UDP";
+
+	conn = "known";
+	if (test->conn == UNKNOWN_CONN)
+		conn = "unknown";
+
+	hops = "no hops";
+	if (test->hops == ONE_HOP)
+		hops = "one hop";
+
+	result = "accept";
+	if (test->result == FORWARD)
+		result = "forward";
+
+	flags = "none";
+	if (test->flags == SYN)
+		flags = "SYN";
+	else if (test->flags == ACK)
+		flags = "ACK";
+
+	return snprintf(buf, len, "%s %s %s %s (%s, flags: %s)", family_str,
+			type, result, conn, hops, flags);
+}
+
+static struct test_cfg tests[] = {
+	{ TCP, ACCEPT, UNKNOWN_CONN, NO_HOPS, SYN },
+	{ TCP, ACCEPT, UNKNOWN_CONN, NO_HOPS, ACK },
+	{ TCP, FORWARD, UNKNOWN_CONN, ONE_HOP, ACK },
+	{ TCP, ACCEPT, KNOWN_CONN, ONE_HOP, ACK },
+	{ UDP, ACCEPT, UNKNOWN_CONN, NO_HOPS, NONE },
+	{ UDP, FORWARD, UNKNOWN_CONN, ONE_HOP, NONE },
+	{ UDP, ACCEPT, KNOWN_CONN, ONE_HOP, NONE },
+};
+
+static void encap_init(encap_headers_t *encap, uint8_t hop_count, uint8_t proto)
+{
+	const uint8_t hlen =
+		(sizeof(struct guehdr) / sizeof(uint32_t)) + hop_count;
+	*encap = (encap_headers_t){
+		.eth = { .h_proto = htons(ETH_P_IP) },
+		.ip = {
+			.ihl = 5,
+			.version = 4,
+			.ttl = IPDEFTTL,
+			.protocol = IPPROTO_UDP,
+			.daddr = htonl(ENCAP_IP)
+		},
+		.udp = {
+			.dest = htons(ENCAP_PORT),
+		},
+		.gue = {
+			.hlen = hlen,
+			.proto_ctype = proto
+		},
+		.unigue = {
+			.hop_count = hop_count
+		},
+	};
+}
+
+static size_t build_input(const struct test_cfg *test, void *const buf,
+			  const struct tuple *tuple)
+{
+	in_port_t sport = tuple->src.port;
+	encap_headers_t encap;
+	struct iphdr ip;
+	struct ipv6hdr ipv6;
+	struct tcphdr tcp;
+	struct udphdr udp;
+	struct in_addr next_hop;
+	uint8_t *p = buf;
+	int proto;
+
+	proto = IPPROTO_IPIP;
+	if (tuple->family == AF_INET6)
+		proto = IPPROTO_IPV6;
+
+	encap_init(&encap, test->hops == ONE_HOP ? 1 : 0, proto);
+	p = mempcpy(p, &encap, sizeof(encap));
+
+	if (test->hops == ONE_HOP) {
+		next_hop = (struct in_addr){ .s_addr = htonl(0x7f000002) };
+		p = mempcpy(p, &next_hop, sizeof(next_hop));
+	}
+
+	proto = IPPROTO_TCP;
+	if (test->type == UDP)
+		proto = IPPROTO_UDP;
+
+	switch (tuple->family) {
+	case AF_INET:
+		ip = (struct iphdr){
+			.ihl = 5,
+			.version = 4,
+			.ttl = IPDEFTTL,
+			.protocol = proto,
+			.saddr = tuple->src.in_addr.s_addr,
+			.daddr = tuple->dst.in_addr.s_addr,
+		};
+		p = mempcpy(p, &ip, sizeof(ip));
+		break;
+	case AF_INET6:
+		ipv6 = (struct ipv6hdr){
+			.version = 6,
+			.hop_limit = IPDEFTTL,
+			.nexthdr = proto,
+			.saddr = tuple->src.in6_addr,
+			.daddr = tuple->dst.in6_addr,
+		};
+		p = mempcpy(p, &ipv6, sizeof(ipv6));
+		break;
+	default:
+		return 0;
+	}
+
+	if (test->conn == UNKNOWN_CONN)
+		sport--;
+
+	switch (test->type) {
+	case TCP:
+		tcp = (struct tcphdr){
+			.source = sport,
+			.dest = tuple->dst.port,
+		};
+		if (test->flags == SYN)
+			tcp.syn = true;
+		if (test->flags == ACK)
+			tcp.ack = true;
+		p = mempcpy(p, &tcp, sizeof(tcp));
+		break;
+	case UDP:
+		udp = (struct udphdr){
+			.source = sport,
+			.dest = tuple->dst.port,
+		};
+		p = mempcpy(p, &udp, sizeof(udp));
+		break;
+	default:
+		return 0;
+	}
+
+	return (void *)p - buf;
+}
+
+static void close_fds(int *fds, int n)
+{
+	int i;
+
+	for (i = 0; i < n; i++)
+		if (fds[i] > 0)
+			close(fds[i]);
+}
+
+void test_cls_redirect(void)
+{
+	struct test_cls_redirect *skel = NULL;
+	struct bpf_prog_test_run_attr tattr = {};
+	int families[] = { AF_INET, AF_INET6 };
+	struct sockaddr_storage ss;
+	struct sockaddr *addr;
+	socklen_t slen;
+	int i, j, err;
+
+	int servers[__NR_KIND][ARRAY_SIZE(families)] = {};
+	int conns[__NR_KIND][ARRAY_SIZE(families)] = {};
+	struct tuple tuples[__NR_KIND][ARRAY_SIZE(families)];
+
+	skel = test_cls_redirect__open();
+	if (CHECK_FAIL(!skel))
+		return;
+
+	skel->rodata->ENCAPSULATION_IP = htonl(ENCAP_IP);
+	skel->rodata->ENCAPSULATION_PORT = htons(ENCAP_PORT);
+
+	if (CHECK_FAIL(test_cls_redirect__load(skel)))
+		goto cleanup;
+
+	addr = (struct sockaddr *)&ss;
+	for (i = 0; i < ARRAY_SIZE(families); i++) {
+		slen = prepare_addr(&ss, families[i]);
+		if (CHECK_FAIL(!slen))
+			goto cleanup;
+
+		if (CHECK_FAIL(!set_up_conn(addr, slen, SOCK_DGRAM,
+					    &servers[UDP][i], &conns[UDP][i],
+					    &tuples[UDP][i])))
+			goto cleanup;
+
+		if (CHECK_FAIL(!set_up_conn(addr, slen, SOCK_STREAM,
+					    &servers[TCP][i], &conns[TCP][i],
+					    &tuples[TCP][i])))
+			goto cleanup;
+	}
+
+	tattr.prog_fd = bpf_program__fd(skel->progs.cls_redirect);
+	for (i = 0; i < ARRAY_SIZE(tests); i++) {
+		struct test_cfg *test = &tests[i];
+
+		for (j = 0; j < ARRAY_SIZE(families); j++) {
+			struct tuple *tuple = &tuples[test->type][j];
+			char input[256];
+			char tmp[256];
+
+			test_str(tmp, sizeof(tmp), test, tuple->family);
+			if (!test__start_subtest(tmp))
+				continue;
+
+			tattr.data_out = tmp;
+			tattr.data_size_out = sizeof(tmp);
+
+			tattr.data_in = input;
+			tattr.data_size_in = build_input(test, input, tuple);
+			if (CHECK_FAIL(!tattr.data_size_in))
+				continue;
+
+			err = bpf_prog_test_run_xattr(&tattr);
+			if (CHECK_FAIL(err))
+				continue;
+
+			if (tattr.retval != TC_ACT_REDIRECT) {
+				PRINT_FAIL("expected TC_ACT_REDIRECT, got %d\n",
+					   tattr.retval);
+				continue;
+			}
+
+			switch (test->result) {
+			case ACCEPT:
+				if (CHECK_FAIL(!was_decapsulated(&tattr)))
+					continue;
+				break;
+			case FORWARD:
+				if (CHECK_FAIL(was_decapsulated(&tattr)))
+					continue;
+				break;
+			default:
+				PRINT_FAIL("unknown result %d\n", test->result);
+				continue;
+			}
+		}
+	}
+
+cleanup:
+	test_cls_redirect__destroy(skel);
+	close_fds((int *)servers, sizeof(servers) / sizeof(servers[0][0]));
+	close_fds((int *)conns, sizeof(conns) / sizeof(conns[0][0]));
+}

tools/testing/selftests/bpf/progs/test_cls_redirect.h

+/* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
+/* Copyright 2019, 2020 Cloudflare */
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <linux/if_ether.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/udp.h>
+
+struct gre_base_hdr {
+	uint16_t flags;
+	uint16_t protocol;
+} __attribute__((packed));
+
+struct guehdr {
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	uint8_t hlen : 5, control : 1, variant : 2;
+#else
+	uint8_t variant : 2, control : 1, hlen : 5;
+#endif
+	uint8_t proto_ctype;
+	uint16_t flags;
+};
+
+struct unigue {
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	uint8_t _r : 2, last_hop_gre : 1, forward_syn : 1, version : 4;
+#else
+	uint8_t version : 4, forward_syn : 1, last_hop_gre : 1, _r : 2;
+#endif
+	uint8_t reserved;
+	uint8_t next_hop;
+	uint8_t hop_count;
+	// Next hops go here
+} __attribute__((packed));
+
+typedef struct {
+	struct ethhdr eth;
+	struct iphdr ip;
+	struct gre_base_hdr gre;
+} __attribute__((packed)) encap_gre_t;
+
+typedef struct {
+	struct ethhdr eth;
+	struct iphdr ip;
+	struct udphdr udp;
+	struct guehdr gue;
+	struct unigue unigue;
+} __attribute__((packed)) encap_headers_t;

tools/testing/selftests/bpf/test_progs.h

@@ -105,6 +105,13 @@ struct ipv6_packet {
 } __packed;
 extern struct ipv6_packet pkt_v6;
 
+#define PRINT_FAIL(format...)                                                  \
+	({                                                                     \
+		test__fail();                                                  \
+		fprintf(stdout, "%s:FAIL:%d ", __func__, __LINE__);            \
+		fprintf(stdout, ##format);                                     \
+	})
+
 #define _CHECK(condition, tag, duration, format...) ({			\
 	int __ret = !!(condition);					\
 	int __save_errno = errno;					\