kernel_optimize_test/samples/bpf/xdp_tx_iptunnel_user.c
Toke Høiland-Jørgensen d50ecc46d1 samples/bpf: Attach XDP programs in driver mode by default
When attaching XDP programs, userspace can set flags to request the attach
mode (generic/SKB mode, driver mode or hw offloaded mode). If no such flags
are requested, the kernel will attempt to attach in driver mode, and then
silently fall back to SKB mode if this fails.

The silent fallback is a major source of user confusion, as users will try
to load a program on a device without XDP support, and instead of an error
they will get the silent fallback behaviour, not notice, and then wonder
why performance is not what they were expecting.

In an attempt to combat this, let's switch all the samples to default to
explicitly requesting driver-mode attach. As part of this, ensure that all
the userspace utilities have a switch to enable SKB mode. For those that
have a switch to request driver mode, keep it but turn it into a no-op.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Link: https://lore.kernel.org/bpf/20191216110742.364456-1-toke@redhat.com
2019-12-16 07:05:38 -08:00

315 lines
7.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2016 Facebook
*/
#include <linux/bpf.h>
#include <linux/if_link.h>
#include <assert.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <net/if.h>
#include <sys/resource.h>
#include <arpa/inet.h>
#include <netinet/ether.h>
#include <unistd.h>
#include <time.h>
#include "libbpf.h"
#include <bpf/bpf.h>
#include "bpf_util.h"
#include "xdp_tx_iptunnel_common.h"
#define STATS_INTERVAL_S 2U
static int ifindex = -1;
static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
static int rxcnt_map_fd;
static __u32 prog_id;
static void int_exit(int sig)
{
__u32 curr_prog_id = 0;
if (ifindex > -1) {
if (bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags)) {
printf("bpf_get_link_xdp_id failed\n");
exit(1);
}
if (prog_id == curr_prog_id)
bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
else if (!curr_prog_id)
printf("couldn't find a prog id on a given iface\n");
else
printf("program on interface changed, not removing\n");
}
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_map_lookup_elem(rxcnt_map_fd, &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 <ifname|ifindex> Interface\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(" -S use skb-mode\n");
printf(" -N enforce native mode\n");
printf(" -F Force loading the XDP prog\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)
{
struct bpf_prog_load_attr prog_load_attr = {
.prog_type = BPF_PROG_TYPE_XDP,
};
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
int min_port = 0, max_port = 0, vip2tnl_map_fd;
const char *optstr = "i:a:p:s:d:m:T:P:FSNh";
unsigned char opt_flags[256] = {};
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
unsigned int kill_after_s = 0;
struct iptnl_info tnl = {};
struct bpf_object *obj;
struct vip vip = {};
char filename[256];
int opt, prog_fd;
int i, err;
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 = if_nametoindex(optarg);
if (!ifindex)
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;
case 'S':
xdp_flags |= XDP_FLAGS_SKB_MODE;
break;
case 'N':
/* default, set below */
break;
case 'F':
xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
break;
default:
usage(argv[0]);
return 1;
}
opt_flags[opt] = 0;
}
if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
xdp_flags |= XDP_FLAGS_DRV_MODE;
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;
}
if (!ifindex) {
fprintf(stderr, "Invalid ifname\n");
return 1;
}
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
prog_load_attr.file = filename;
if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
return 1;
if (!prog_fd) {
printf("bpf_prog_load_xattr: %s\n", strerror(errno));
return 1;
}
rxcnt_map_fd = bpf_object__find_map_fd_by_name(obj, "rxcnt");
vip2tnl_map_fd = bpf_object__find_map_fd_by_name(obj, "vip2tnl");
if (vip2tnl_map_fd < 0 || rxcnt_map_fd < 0) {
printf("bpf_object__find_map_fd_by_name failed\n");
return 1;
}
signal(SIGINT, int_exit);
signal(SIGTERM, int_exit);
while (min_port <= max_port) {
vip.dport = htons(min_port++);
if (bpf_map_update_elem(vip2tnl_map_fd, &vip, &tnl,
BPF_NOEXIST)) {
perror("bpf_map_update_elem(&vip2tnl)");
return 1;
}
}
if (bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags) < 0) {
printf("link set xdp fd failed\n");
return 1;
}
err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
if (err) {
printf("can't get prog info - %s\n", strerror(errno));
return err;
}
prog_id = info.id;
poll_stats(kill_after_s);
bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
return 0;
}