bpf: xdp: Add XDP example for head adjustment

The XDP prog checks if the incoming packet matches any VIP:PORT
combination in the BPF hashmap.  If it is, it will encapsulate
the packet with a IPv4/v6 header as instructed by the value of
the BPF hashmap and then XDP_TX it out.

The VIP:PORT -> IP-Encap-Info can be specified by the cmd args
of the user prog.

Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 256 insertions, 0 deletions

diff --git a/samples/bpf/xdp_tx_iptunnel_user.c b/samples/bpf/xdp_tx_iptunnel_user.c
new file mode 100644
index 000000000000..7a71f5c74684
--- /dev/null
+++ b/samples/bpf/xdp_tx_iptunnel_user.c
@@ -0,0 +1,256 @@
+/* Copyright (c) 2016 Facebook
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#include <linux/bpf.h>
+#include <assert.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/resource.h>
+#include <arpa/inet.h>
+#include <netinet/ether.h>
+#include <unistd.h>
+#include <time.h>
+#include "bpf_load.h"
+#include "libbpf.h"
+#include "bpf_util.h"
+#include "xdp_tx_iptunnel_common.h"
+
+#define STATS_INTERVAL_S 2U
+
+static int ifindex = -1;
+
+static void int_exit(int sig)
+{
+	if (ifindex > -1)
+		set_link_xdp_fd(ifindex, -1);
+	exit(0);
+}
+
+/* simple per-protocol drop counter
+ */
+static void poll_stats(unsigned int kill_after_s)
+{
+	const unsigned int nr_protos = 256;
+	unsigned int nr_cpus = bpf_num_possible_cpus();
+	time_t started_at = time(NULL);
+	__u64 values[nr_cpus], prev[nr_protos][nr_cpus];
+	__u32 proto;
+	int i;
+
+	memset(prev, 0, sizeof(prev));
+
+	while (!kill_after_s || time(NULL) - started_at <= kill_after_s) {
+		sleep(STATS_INTERVAL_S);
+
+		for (proto = 0; proto < nr_protos; proto++) {
+			__u64 sum = 0;
+
+			assert(bpf_lookup_elem(map_fd[0], &proto, values) == 0);
+			for (i = 0; i < nr_cpus; i++)
+				sum += (values[i] - prev[proto][i]);
+
+			if (sum)
+				printf("proto %u: sum:%10llu pkts, rate:%10llu pkts/s\n",
+				       proto, sum, sum / STATS_INTERVAL_S);
+			memcpy(prev[proto], values, sizeof(values));
+		}
+	}
+}
+
+static void usage(const char *cmd)
+{
+	printf("Start a XDP prog which encapsulates incoming packets\n"
+	       "in an IPv4/v6 header and XDP_TX it out.  The dst <VIP:PORT>\n"
+	       "is used to select packets to encapsulate\n\n");
+	printf("Usage: %s [...]\n", cmd);
+	printf("    -i <ifindex> Interface Index\n");
+	printf("    -a <vip-service-address> IPv4 or IPv6\n");
+	printf("    -p <vip-service-port> A port range (e.g. 433-444) is also allowed\n");
+	printf("    -s <source-ip> Used in the IPTunnel header\n");
+	printf("    -d <dest-ip> Used in the IPTunnel header\n");
+	printf("    -m <dest-MAC> Used in sending the IP Tunneled pkt\n");
+	printf("    -T <stop-after-X-seconds> Default: 0 (forever)\n");
+	printf("    -P <IP-Protocol> Default is TCP\n");
+	printf("    -h Display this help\n");
+}
+
+static int parse_ipstr(const char *ipstr, unsigned int *addr)
+{
+	if (inet_pton(AF_INET6, ipstr, addr) == 1) {
+		return AF_INET6;
+	} else if (inet_pton(AF_INET, ipstr, addr) == 1) {
+		addr[1] = addr[2] = addr[3] = 0;
+		return AF_INET;
+	}
+
+	fprintf(stderr, "%s is an invalid IP\n", ipstr);
+	return AF_UNSPEC;
+}
+
+static int parse_ports(const char *port_str, int *min_port, int *max_port)
+{
+	char *end;
+	long tmp_min_port;
+	long tmp_max_port;
+
+	tmp_min_port = strtol(optarg, &end, 10);
+	if (tmp_min_port < 1 || tmp_min_port > 65535) {
+		fprintf(stderr, "Invalid port(s):%s\n", optarg);
+		return 1;
+	}
+
+	if (*end == '-') {
+		end++;
+		tmp_max_port = strtol(end, NULL, 10);
+		if (tmp_max_port < 1 || tmp_max_port > 65535) {
+			fprintf(stderr, "Invalid port(s):%s\n", optarg);
+			return 1;
+		}
+	} else {
+		tmp_max_port = tmp_min_port;
+	}
+
+	if (tmp_min_port > tmp_max_port) {
+		fprintf(stderr, "Invalid port(s):%s\n", optarg);
+		return 1;
+	}
+
+	if (tmp_max_port - tmp_min_port + 1 > MAX_IPTNL_ENTRIES) {
+		fprintf(stderr, "Port range (%s) is larger than %u\n",
+			port_str, MAX_IPTNL_ENTRIES);
+		return 1;
+	}
+	*min_port = tmp_min_port;
+	*max_port = tmp_max_port;
+
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	unsigned char opt_flags[256] = {};
+	unsigned int kill_after_s = 0;
+	const char *optstr = "i:a:p:s:d:m:T:P:h";
+	int min_port = 0, max_port = 0;
+	struct iptnl_info tnl = {};
+	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+	struct vip vip = {};
+	char filename[256];
+	int opt;
+	int i;
+
+	tnl.family = AF_UNSPEC;
+	vip.protocol = IPPROTO_TCP;
+
+	for (i = 0; i < strlen(optstr); i++)
+		if (optstr[i] != 'h' && 'a' <= optstr[i] && optstr[i] <= 'z')
+			opt_flags[(unsigned char)optstr[i]] = 1;
+
+	while ((opt = getopt(argc, argv, optstr)) != -1) {
+		unsigned short family;
+		unsigned int *v6;
+
+		switch (opt) {
+		case 'i':
+			ifindex = atoi(optarg);
+			break;
+		case 'a':
+			vip.family = parse_ipstr(optarg, vip.daddr.v6);
+			if (vip.family == AF_UNSPEC)
+				return 1;
+			break;
+		case 'p':
+			if (parse_ports(optarg, &min_port, &max_port))
+				return 1;
+			break;
+		case 'P':
+			vip.protocol = atoi(optarg);
+			break;
+		case 's':
+		case 'd':
+			if (opt == 's')
+				v6 = tnl.saddr.v6;
+			else
+				v6 = tnl.daddr.v6;
+
+			family = parse_ipstr(optarg, v6);
+			if (family == AF_UNSPEC)
+				return 1;
+			if (tnl.family == AF_UNSPEC) {
+				tnl.family = family;
+			} else if (tnl.family != family) {
+				fprintf(stderr,
+					"The IP version of the src and dst addresses used in the IP encapsulation does not match\n");
+				return 1;
+			}
+			break;
+		case 'm':
+			if (!ether_aton_r(optarg,
+					  (struct ether_addr *)tnl.dmac)) {
+				fprintf(stderr, "Invalid mac address:%s\n",
+					optarg);
+				return 1;
+			}
+			break;
+		case 'T':
+			kill_after_s = atoi(optarg);
+			break;
+		default:
+			usage(argv[0]);
+			return 1;
+		}
+		opt_flags[opt] = 0;
+	}
+
+	for (i = 0; i < strlen(optstr); i++) {
+		if (opt_flags[(unsigned int)optstr[i]]) {
+			fprintf(stderr, "Missing argument -%c\n", optstr[i]);
+			usage(argv[0]);
+			return 1;
+		}
+	}
+
+	if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+		perror("setrlimit(RLIMIT_MEMLOCK, RLIM_INFINITY)");
+		return 1;
+	}
+
+	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+	if (load_bpf_file(filename)) {
+		printf("%s", bpf_log_buf);
+		return 1;
+	}
+
+	if (!prog_fd[0]) {
+		printf("load_bpf_file: %s\n", strerror(errno));
+		return 1;
+	}
+
+	signal(SIGINT, int_exit);
+
+	while (min_port <= max_port) {
+		vip.dport = htons(min_port++);
+		if (bpf_update_elem(map_fd[1], &vip, &tnl, BPF_NOEXIST)) {
+			perror("bpf_update_elem(&vip2tnl)");
+			return 1;
+		}
+	}
+
+	if (set_link_xdp_fd(ifindex, prog_fd[0]) < 0) {
+		printf("link set xdp fd failed\n");
+		return 1;
+	}
+
+	poll_stats(kill_after_s);
+
+	set_link_xdp_fd(ifindex, -1);
+
+	return 0;
+}