bpf: selftests: test skb->tstamp in redirect_neigh

This patch adds tests on forwarding the delivery_time for
the following cases
- tcp/udp + ip4/ip6 + bpf_redirect_neigh
- tcp/udp + ip4/ip6 + ip[6]_forward
- bpf_skb_set_delivery_time
- The old rcv timestamp expectation on tc-bpf@ingress
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/bpf/progs/test_tc_dtime.c

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2022 Meta
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <linux/bpf.h>
+#include <linux/stddef.h>
+#include <linux/pkt_cls.h>
+#include <linux/if_ether.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+#include <sys/socket.h>
+
+/* veth_src --- veth_src_fwd --- veth_det_fwd --- veth_dst
+ *           |                                 |
+ *  ns_src   |              ns_fwd             |   ns_dst
+ *
+ * ns_src and ns_dst: ENDHOST namespace
+ *            ns_fwd: Fowarding namespace
+ */
+
+#define ctx_ptr(field)		(void *)(long)(field)
+
+#define ip4_src			__bpf_htonl(0xac100164) /* 172.16.1.100 */
+#define ip4_dst			__bpf_htonl(0xac100264) /* 172.16.2.100 */
+
+#define ip6_src			{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
+				  0x00, 0x01, 0xde, 0xad, 0xbe, 0xef, 0xca, 0xfe }
+#define ip6_dst			{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
+				  0x00, 0x02, 0xde, 0xad, 0xbe, 0xef, 0xca, 0xfe }
+
+#define v6_equal(a, b)		(a.s6_addr32[0] == b.s6_addr32[0] && \
+				 a.s6_addr32[1] == b.s6_addr32[1] && \
+				 a.s6_addr32[2] == b.s6_addr32[2] && \
+				 a.s6_addr32[3] == b.s6_addr32[3])
+
+volatile const __u32 IFINDEX_SRC;
+volatile const __u32 IFINDEX_DST;
+
+#define EGRESS_ENDHOST_MAGIC	0x0b9fbeef
+#define INGRESS_FWDNS_MAGIC	0x1b9fbeef
+#define EGRESS_FWDNS_MAGIC	0x2b9fbeef
+
+enum {
+	INGRESS_FWDNS_P100,
+	INGRESS_FWDNS_P101,
+	EGRESS_FWDNS_P100,
+	EGRESS_FWDNS_P101,
+	INGRESS_ENDHOST,
+	EGRESS_ENDHOST,
+	SET_DTIME,
+	__MAX_CNT,
+};
+
+enum {
+	TCP_IP6_CLEAR_DTIME,
+	TCP_IP4,
+	TCP_IP6,
+	UDP_IP4,
+	UDP_IP6,
+	TCP_IP4_RT_FWD,
+	TCP_IP6_RT_FWD,
+	UDP_IP4_RT_FWD,
+	UDP_IP6_RT_FWD,
+	UKN_TEST,
+	__NR_TESTS,
+};
+
+enum {
+	SRC_NS = 1,
+	DST_NS,
+};
+
+__u32 dtimes[__NR_TESTS][__MAX_CNT] = {};
+__u32 errs[__NR_TESTS][__MAX_CNT] = {};
+__u32 test = 0;
+
+static void inc_dtimes(__u32 idx)
+{
+	if (test < __NR_TESTS)
+		dtimes[test][idx]++;
+	else
+		dtimes[UKN_TEST][idx]++;
+}
+
+static void inc_errs(__u32 idx)
+{
+	if (test < __NR_TESTS)
+		errs[test][idx]++;
+	else
+		errs[UKN_TEST][idx]++;
+}
+
+static int skb_proto(int type)
+{
+	return type & 0xff;
+}
+
+static int skb_ns(int type)
+{
+	return (type >> 8) & 0xff;
+}
+
+static bool fwdns_clear_dtime(void)
+{
+	return test == TCP_IP6_CLEAR_DTIME;
+}
+
+static bool bpf_fwd(void)
+{
+	return test < TCP_IP4_RT_FWD;
+}
+
+/* -1: parse error: TC_ACT_SHOT
+ *  0: not testing traffic: TC_ACT_OK
+ * >0: first byte is the inet_proto, second byte has the netns
+ *     of the sender
+ */
+static int skb_get_type(struct __sk_buff *skb)
+{
+	void *data_end = ctx_ptr(skb->data_end);
+	void *data = ctx_ptr(skb->data);
+	__u8 inet_proto = 0, ns = 0;
+	struct ipv6hdr *ip6h;
+	struct iphdr *iph;
+
+	switch (skb->protocol) {
+	case __bpf_htons(ETH_P_IP):
+		iph = data + sizeof(struct ethhdr);
+		if (iph + 1 > data_end)
+			return -1;
+		if (iph->saddr == ip4_src)
+			ns = SRC_NS;
+		else if (iph->saddr == ip4_dst)
+			ns = DST_NS;
+		inet_proto = iph->protocol;
+		break;
+	case __bpf_htons(ETH_P_IPV6):
+		ip6h = data + sizeof(struct ethhdr);
+		if (ip6h + 1 > data_end)
+			return -1;
+		if (v6_equal(ip6h->saddr, (struct in6_addr)ip6_src))
+			ns = SRC_NS;
+		else if (v6_equal(ip6h->saddr, (struct in6_addr)ip6_dst))
+			ns = DST_NS;
+		inet_proto = ip6h->nexthdr;
+		break;
+	default:
+		return 0;
+	}
+
+	if ((inet_proto != IPPROTO_TCP && inet_proto != IPPROTO_UDP) || !ns)
+		return 0;
+
+	return (ns << 8 | inet_proto);
+}
+
+/* format: direction@iface@netns
+ * egress@veth_(src|dst)@ns_(src|dst)
+ */
+SEC("tc")
+int egress_host(struct __sk_buff *skb)
+{
+	int skb_type;
+
+	skb_type = skb_get_type(skb);
+	if (skb_type == -1)
+		return TC_ACT_SHOT;
+	if (!skb_type)
+		return TC_ACT_OK;
+
+	if (skb_proto(skb_type) == IPPROTO_TCP) {
+		if (skb->delivery_time_type == BPF_SKB_DELIVERY_TIME_MONO &&
+		    skb->tstamp)
+			inc_dtimes(EGRESS_ENDHOST);
+		else
+			inc_errs(EGRESS_ENDHOST);
+	} else {
+		if (skb->delivery_time_type == BPF_SKB_DELIVERY_TIME_UNSPEC &&
+		    skb->tstamp)
+			inc_dtimes(EGRESS_ENDHOST);
+		else
+			inc_errs(EGRESS_ENDHOST);
+	}
+
+	skb->tstamp = EGRESS_ENDHOST_MAGIC;
+
+	return TC_ACT_OK;
+}
+
+/* ingress@veth_(src|dst)@ns_(src|dst) */
+SEC("tc")
+int ingress_host(struct __sk_buff *skb)
+{
+	int skb_type;
+
+	skb_type = skb_get_type(skb);
+	if (skb_type == -1)
+		return TC_ACT_SHOT;
+	if (!skb_type)
+		return TC_ACT_OK;
+
+	if (skb->delivery_time_type == BPF_SKB_DELIVERY_TIME_MONO &&
+	    skb->tstamp == EGRESS_FWDNS_MAGIC)
+		inc_dtimes(INGRESS_ENDHOST);
+	else
+		inc_errs(INGRESS_ENDHOST);
+
+	return TC_ACT_OK;
+}
+
+/* ingress@veth_(src|dst)_fwd@ns_fwd priority 100 */
+SEC("tc")
+int ingress_fwdns_prio100(struct __sk_buff *skb)
+{
+	int skb_type;
+
+	skb_type = skb_get_type(skb);
+	if (skb_type == -1)
+		return TC_ACT_SHOT;
+	if (!skb_type)
+		return TC_ACT_OK;
+
+	/* delivery_time is only available to the ingress
+	 * if the tc-bpf checks the skb->delivery_time_type.
+	 */
+	if (skb->tstamp == EGRESS_ENDHOST_MAGIC)
+		inc_errs(INGRESS_FWDNS_P100);
+
+	if (fwdns_clear_dtime())
+		skb->tstamp = 0;
+
+	return TC_ACT_UNSPEC;
+}
+
+/* egress@veth_(src|dst)_fwd@ns_fwd priority 100 */
+SEC("tc")
+int egress_fwdns_prio100(struct __sk_buff *skb)
+{
+	int skb_type;
+
+	skb_type = skb_get_type(skb);
+	if (skb_type == -1)
+		return TC_ACT_SHOT;
+	if (!skb_type)
+		return TC_ACT_OK;
+
+	/* delivery_time is always available to egress even
+	 * the tc-bpf did not use the delivery_time_type.
+	 */
+	if (skb->tstamp == INGRESS_FWDNS_MAGIC)
+		inc_dtimes(EGRESS_FWDNS_P100);
+	else
+		inc_errs(EGRESS_FWDNS_P100);
+
+	if (fwdns_clear_dtime())
+		skb->tstamp = 0;
+
+	return TC_ACT_UNSPEC;
+}
+
+/* ingress@veth_(src|dst)_fwd@ns_fwd priority 101 */
+SEC("tc")
+int ingress_fwdns_prio101(struct __sk_buff *skb)
+{
+	__u64 expected_dtime = EGRESS_ENDHOST_MAGIC;
+	int skb_type;
+
+	skb_type = skb_get_type(skb);
+	if (skb_type == -1 || !skb_type)
+		/* Should have handled in prio100 */
+		return TC_ACT_SHOT;
+
+	if (skb_proto(skb_type) == IPPROTO_UDP)
+		expected_dtime = 0;
+
+	if (skb->delivery_time_type) {
+		if (fwdns_clear_dtime() ||
+		    skb->delivery_time_type != BPF_SKB_DELIVERY_TIME_MONO ||
+		    skb->tstamp != expected_dtime)
+			inc_errs(INGRESS_FWDNS_P101);
+		else
+			inc_dtimes(INGRESS_FWDNS_P101);
+	} else {
+		if (!fwdns_clear_dtime() && expected_dtime)
+			inc_errs(INGRESS_FWDNS_P101);
+	}
+
+	if (skb->delivery_time_type == BPF_SKB_DELIVERY_TIME_MONO) {
+		skb->tstamp = INGRESS_FWDNS_MAGIC;
+	} else {
+		if (bpf_skb_set_delivery_time(skb, INGRESS_FWDNS_MAGIC,
+					      BPF_SKB_DELIVERY_TIME_MONO))
+			inc_errs(SET_DTIME);
+		if (!bpf_skb_set_delivery_time(skb, INGRESS_FWDNS_MAGIC,
+					       BPF_SKB_DELIVERY_TIME_UNSPEC))
+			inc_errs(SET_DTIME);
+	}
+
+	if (skb_ns(skb_type) == SRC_NS)
+		return bpf_fwd() ?
+			bpf_redirect_neigh(IFINDEX_DST, NULL, 0, 0) : TC_ACT_OK;
+	else
+		return bpf_fwd() ?
+			bpf_redirect_neigh(IFINDEX_SRC, NULL, 0, 0) : TC_ACT_OK;
+}
+
+/* egress@veth_(src|dst)_fwd@ns_fwd priority 101 */
+SEC("tc")
+int egress_fwdns_prio101(struct __sk_buff *skb)
+{
+	int skb_type;
+
+	skb_type = skb_get_type(skb);
+	if (skb_type == -1 || !skb_type)
+		/* Should have handled in prio100 */
+		return TC_ACT_SHOT;
+
+	if (skb->delivery_time_type) {
+		if (fwdns_clear_dtime() ||
+		    skb->delivery_time_type != BPF_SKB_DELIVERY_TIME_MONO ||
+		    skb->tstamp != INGRESS_FWDNS_MAGIC)
+			inc_errs(EGRESS_FWDNS_P101);
+		else
+			inc_dtimes(EGRESS_FWDNS_P101);
+	} else {
+		if (!fwdns_clear_dtime())
+			inc_errs(EGRESS_FWDNS_P101);
+	}
+
+	if (skb->delivery_time_type == BPF_SKB_DELIVERY_TIME_MONO) {
+		skb->tstamp = EGRESS_FWDNS_MAGIC;
+	} else {
+		if (bpf_skb_set_delivery_time(skb, EGRESS_FWDNS_MAGIC,
+					      BPF_SKB_DELIVERY_TIME_MONO))
+			inc_errs(SET_DTIME);
+		if (!bpf_skb_set_delivery_time(skb, EGRESS_FWDNS_MAGIC,
+					       BPF_SKB_DELIVERY_TIME_UNSPEC))
+			inc_errs(SET_DTIME);
+	}
+
+	return TC_ACT_OK;
+}
+
+char __license[] SEC("license") = "GPL";