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linux/samples/bpf/xdp_router_ipv4_user.c

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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (C) 2017 Cavium, Inc.
*/
#include <linux/bpf.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <assert.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#include <bpf/bpf.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <poll.h>
#include <net/if.h>
#include <netdb.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include "bpf_util.h"
#include "libbpf.h"
#include <sys/resource.h>
#include <libgen.h>
int sock, sock_arp, flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
static int total_ifindex;
static int *ifindex_list;
static __u32 *prog_id_list;
char buf[8192];
static int lpm_map_fd;
static int rxcnt_map_fd;
static int arp_table_map_fd;
static int exact_match_map_fd;
static int tx_port_map_fd;
static int get_route_table(int rtm_family);
static void int_exit(int sig)
{
__u32 prog_id = 0;
int i = 0;
for (i = 0; i < total_ifindex; i++) {
if (bpf_get_link_xdp_id(ifindex_list[i], &prog_id, flags)) {
printf("bpf_get_link_xdp_id on iface %d failed\n",
ifindex_list[i]);
exit(1);
}
if (prog_id_list[i] == prog_id)
bpf_set_link_xdp_fd(ifindex_list[i], -1, flags);
else if (!prog_id)
printf("couldn't find a prog id on iface %d\n",
ifindex_list[i]);
else
printf("program on iface %d changed, not removing\n",
ifindex_list[i]);
prog_id = 0;
}
exit(0);
}
static void close_and_exit(int sig)
{
close(sock);
close(sock_arp);
int_exit(0);
}
/* Get the mac address of the interface given interface name */
static __be64 getmac(char *iface)
{
struct ifreq ifr;
__be64 mac = 0;
int fd, i;
fd = socket(AF_INET, SOCK_DGRAM, 0);
ifr.ifr_addr.sa_family = AF_INET;
strncpy(ifr.ifr_name, iface, IFNAMSIZ - 1);
if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0) {
printf("ioctl failed leaving....\n");
return -1;
}
for (i = 0; i < 6 ; i++)
*((__u8 *)&mac + i) = (__u8)ifr.ifr_hwaddr.sa_data[i];
close(fd);
return mac;
}
static int recv_msg(struct sockaddr_nl sock_addr, int sock)
{
struct nlmsghdr *nh;
int len, nll = 0;
char *buf_ptr;
buf_ptr = buf;
while (1) {
len = recv(sock, buf_ptr, sizeof(buf) - nll, 0);
if (len < 0)
return len;
nh = (struct nlmsghdr *)buf_ptr;
if (nh->nlmsg_type == NLMSG_DONE)
break;
buf_ptr += len;
nll += len;
if ((sock_addr.nl_groups & RTMGRP_NEIGH) == RTMGRP_NEIGH)
break;
if ((sock_addr.nl_groups & RTMGRP_IPV4_ROUTE) == RTMGRP_IPV4_ROUTE)
break;
}
return nll;
}
/* Function to parse the route entry returned by netlink
* Updates the route entry related map entries
*/
static void read_route(struct nlmsghdr *nh, int nll)
{
char dsts[24], gws[24], ifs[16], dsts_len[24], metrics[24];
struct bpf_lpm_trie_key *prefix_key;
struct rtattr *rt_attr;
struct rtmsg *rt_msg;
int rtm_family;
int rtl;
int i;
struct route_table {
int dst_len, iface, metric;
char *iface_name;
__be32 dst, gw;
__be64 mac;
} route;
struct arp_table {
__be64 mac;
__be32 dst;
};
struct direct_map {
struct arp_table arp;
int ifindex;
__be64 mac;
} direct_entry;
if (nh->nlmsg_type == RTM_DELROUTE)
printf("DELETING Route entry\n");
else if (nh->nlmsg_type == RTM_GETROUTE)
printf("READING Route entry\n");
else if (nh->nlmsg_type == RTM_NEWROUTE)
printf("NEW Route entry\n");
else
printf("%d\n", nh->nlmsg_type);
memset(&route, 0, sizeof(route));
printf("Destination\t\tGateway\t\tGenmask\t\tMetric\t\tIface\n");
for (; NLMSG_OK(nh, nll); nh = NLMSG_NEXT(nh, nll)) {
rt_msg = (struct rtmsg *)NLMSG_DATA(nh);
rtm_family = rt_msg->rtm_family;
if (rtm_family == AF_INET)
if (rt_msg->rtm_table != RT_TABLE_MAIN)
continue;
rt_attr = (struct rtattr *)RTM_RTA(rt_msg);
rtl = RTM_PAYLOAD(nh);
for (; RTA_OK(rt_attr, rtl); rt_attr = RTA_NEXT(rt_attr, rtl)) {
switch (rt_attr->rta_type) {
case NDA_DST:
sprintf(dsts, "%u",
(*((__be32 *)RTA_DATA(rt_attr))));
break;
case RTA_GATEWAY:
sprintf(gws, "%u",
*((__be32 *)RTA_DATA(rt_attr)));
break;
case RTA_OIF:
sprintf(ifs, "%u",
*((int *)RTA_DATA(rt_attr)));
break;
case RTA_METRICS:
sprintf(metrics, "%u",
*((int *)RTA_DATA(rt_attr)));
default:
break;
}
}
sprintf(dsts_len, "%d", rt_msg->rtm_dst_len);
route.dst = atoi(dsts);
route.dst_len = atoi(dsts_len);
route.gw = atoi(gws);
route.iface = atoi(ifs);
route.metric = atoi(metrics);
route.iface_name = alloca(sizeof(char *) * IFNAMSIZ);
route.iface_name = if_indextoname(route.iface, route.iface_name);
route.mac = getmac(route.iface_name);
if (route.mac == -1)
int_exit(0);
assert(bpf_map_update_elem(tx_port_map_fd,
&route.iface, &route.iface, 0) == 0);
if (rtm_family == AF_INET) {
struct trie_value {
__u8 prefix[4];
__be64 value;
int ifindex;
int metric;
__be32 gw;
} *prefix_value;
prefix_key = alloca(sizeof(*prefix_key) + 3);
prefix_value = alloca(sizeof(*prefix_value));
prefix_key->prefixlen = 32;
prefix_key->prefixlen = route.dst_len;
direct_entry.mac = route.mac & 0xffffffffffff;
direct_entry.ifindex = route.iface;
direct_entry.arp.mac = 0;
direct_entry.arp.dst = 0;
if (route.dst_len == 32) {
if (nh->nlmsg_type == RTM_DELROUTE) {
assert(bpf_map_delete_elem(exact_match_map_fd,
&route.dst) == 0);
} else {
if (bpf_map_lookup_elem(arp_table_map_fd,
&route.dst,
&direct_entry.arp.mac) == 0)
direct_entry.arp.dst = route.dst;
assert(bpf_map_update_elem(exact_match_map_fd,
&route.dst,
&direct_entry, 0) == 0);
}
}
for (i = 0; i < 4; i++)
prefix_key->data[i] = (route.dst >> i * 8) & 0xff;
printf("%3d.%d.%d.%d\t\t%3x\t\t%d\t\t%d\t\t%s\n",
(int)prefix_key->data[0],
(int)prefix_key->data[1],
(int)prefix_key->data[2],
(int)prefix_key->data[3],
route.gw, route.dst_len,
route.metric,
route.iface_name);
if (bpf_map_lookup_elem(lpm_map_fd, prefix_key,
prefix_value) < 0) {
for (i = 0; i < 4; i++)
prefix_value->prefix[i] = prefix_key->data[i];
prefix_value->value = route.mac & 0xffffffffffff;
prefix_value->ifindex = route.iface;
prefix_value->gw = route.gw;
prefix_value->metric = route.metric;
assert(bpf_map_update_elem(lpm_map_fd,
prefix_key,
prefix_value, 0
) == 0);
} else {
if (nh->nlmsg_type == RTM_DELROUTE) {
printf("deleting entry\n");
printf("prefix key=%d.%d.%d.%d/%d",
prefix_key->data[0],
prefix_key->data[1],
prefix_key->data[2],
prefix_key->data[3],
prefix_key->prefixlen);
assert(bpf_map_delete_elem(lpm_map_fd,
prefix_key
) == 0);
/* Rereading the route table to check if
* there is an entry with the same
* prefix but a different metric as the
* deleted enty.
*/
get_route_table(AF_INET);
} else if (prefix_key->data[0] ==
prefix_value->prefix[0] &&
prefix_key->data[1] ==
prefix_value->prefix[1] &&
prefix_key->data[2] ==
prefix_value->prefix[2] &&
prefix_key->data[3] ==
prefix_value->prefix[3] &&
route.metric >= prefix_value->metric) {
continue;
} else {
for (i = 0; i < 4; i++)
prefix_value->prefix[i] =
prefix_key->data[i];
prefix_value->value =
route.mac & 0xffffffffffff;
prefix_value->ifindex = route.iface;
prefix_value->gw = route.gw;
prefix_value->metric = route.metric;
assert(bpf_map_update_elem(lpm_map_fd,
prefix_key,
prefix_value,
0) == 0);
}
}
}
memset(&route, 0, sizeof(route));
memset(dsts, 0, sizeof(dsts));
memset(dsts_len, 0, sizeof(dsts_len));
memset(gws, 0, sizeof(gws));
memset(ifs, 0, sizeof(ifs));
memset(&route, 0, sizeof(route));
}
}
/* Function to read the existing route table when the process is launched*/
static int get_route_table(int rtm_family)
{
struct sockaddr_nl sa;
struct nlmsghdr *nh;
int sock, seq = 0;
struct msghdr msg;
struct iovec iov;
int ret = 0;
int nll;
struct {
struct nlmsghdr nl;
struct rtmsg rt;
char buf[8192];
} req;
sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (sock < 0) {
printf("open netlink socket: %s\n", strerror(errno));
return -1;
}
memset(&sa, 0, sizeof(sa));
sa.nl_family = AF_NETLINK;
if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
printf("bind to netlink: %s\n", strerror(errno));
ret = -1;
goto cleanup;
}
memset(&req, 0, sizeof(req));
req.nl.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
req.nl.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
req.nl.nlmsg_type = RTM_GETROUTE;
req.rt.rtm_family = rtm_family;
req.rt.rtm_table = RT_TABLE_MAIN;
req.nl.nlmsg_pid = 0;
req.nl.nlmsg_seq = ++seq;
memset(&msg, 0, sizeof(msg));
iov.iov_base = (void *)&req.nl;
iov.iov_len = req.nl.nlmsg_len;
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
ret = sendmsg(sock, &msg, 0);
if (ret < 0) {
printf("send to netlink: %s\n", strerror(errno));
ret = -1;
goto cleanup;
}
memset(buf, 0, sizeof(buf));
nll = recv_msg(sa, sock);
if (nll < 0) {
printf("recv from netlink: %s\n", strerror(nll));
ret = -1;
goto cleanup;
}
nh = (struct nlmsghdr *)buf;
read_route(nh, nll);
cleanup:
close(sock);
return ret;
}
/* Function to parse the arp entry returned by netlink
* Updates the arp entry related map entries
*/
static void read_arp(struct nlmsghdr *nh, int nll)
{
struct rtattr *rt_attr;
char dsts[24], mac[24];
struct ndmsg *rt_msg;
int rtl, ndm_family;
struct arp_table {
__be64 mac;
__be32 dst;
} arp_entry;
struct direct_map {
struct arp_table arp;
int ifindex;
__be64 mac;
} direct_entry;
if (nh->nlmsg_type == RTM_GETNEIGH)
printf("READING arp entry\n");
printf("Address\tHwAddress\n");
for (; NLMSG_OK(nh, nll); nh = NLMSG_NEXT(nh, nll)) {
rt_msg = (struct ndmsg *)NLMSG_DATA(nh);
rt_attr = (struct rtattr *)RTM_RTA(rt_msg);
ndm_family = rt_msg->ndm_family;
rtl = RTM_PAYLOAD(nh);
for (; RTA_OK(rt_attr, rtl); rt_attr = RTA_NEXT(rt_attr, rtl)) {
switch (rt_attr->rta_type) {
case NDA_DST:
sprintf(dsts, "%u",
*((__be32 *)RTA_DATA(rt_attr)));
break;
case NDA_LLADDR:
sprintf(mac, "%lld",
*((__be64 *)RTA_DATA(rt_attr)));
break;
default:
break;
}
}
arp_entry.dst = atoi(dsts);
arp_entry.mac = atol(mac);
printf("%x\t\t%llx\n", arp_entry.dst, arp_entry.mac);
if (ndm_family == AF_INET) {
if (bpf_map_lookup_elem(exact_match_map_fd,
&arp_entry.dst,
&direct_entry) == 0) {
if (nh->nlmsg_type == RTM_DELNEIGH) {
direct_entry.arp.dst = 0;
direct_entry.arp.mac = 0;
} else if (nh->nlmsg_type == RTM_NEWNEIGH) {
direct_entry.arp.dst = arp_entry.dst;
direct_entry.arp.mac = arp_entry.mac;
}
assert(bpf_map_update_elem(exact_match_map_fd,
&arp_entry.dst,
&direct_entry, 0
) == 0);
memset(&direct_entry, 0, sizeof(direct_entry));
}
if (nh->nlmsg_type == RTM_DELNEIGH) {
assert(bpf_map_delete_elem(arp_table_map_fd,
&arp_entry.dst) == 0);
} else if (nh->nlmsg_type == RTM_NEWNEIGH) {
assert(bpf_map_update_elem(arp_table_map_fd,
&arp_entry.dst,
&arp_entry.mac, 0
) == 0);
}
}
memset(&arp_entry, 0, sizeof(arp_entry));
memset(dsts, 0, sizeof(dsts));
}
}
/* Function to read the existing arp table when the process is launched*/
static int get_arp_table(int rtm_family)
{
struct sockaddr_nl sa;
struct nlmsghdr *nh;
int sock, seq = 0;
struct msghdr msg;
struct iovec iov;
int ret = 0;
int nll;
struct {
struct nlmsghdr nl;
struct ndmsg rt;
char buf[8192];
} req;
sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (sock < 0) {
printf("open netlink socket: %s\n", strerror(errno));
return -1;
}
memset(&sa, 0, sizeof(sa));
sa.nl_family = AF_NETLINK;
if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
printf("bind to netlink: %s\n", strerror(errno));
ret = -1;
goto cleanup;
}
memset(&req, 0, sizeof(req));
req.nl.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
req.nl.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
req.nl.nlmsg_type = RTM_GETNEIGH;
req.rt.ndm_state = NUD_REACHABLE;
req.rt.ndm_family = rtm_family;
req.nl.nlmsg_pid = 0;
req.nl.nlmsg_seq = ++seq;
memset(&msg, 0, sizeof(msg));
iov.iov_base = (void *)&req.nl;
iov.iov_len = req.nl.nlmsg_len;
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
ret = sendmsg(sock, &msg, 0);
if (ret < 0) {
printf("send to netlink: %s\n", strerror(errno));
ret = -1;
goto cleanup;
}
memset(buf, 0, sizeof(buf));
nll = recv_msg(sa, sock);
if (nll < 0) {
printf("recv from netlink: %s\n", strerror(nll));
ret = -1;
goto cleanup;
}
nh = (struct nlmsghdr *)buf;
read_arp(nh, nll);
cleanup:
close(sock);
return ret;
}
/* Function to keep track and update changes in route and arp table
* Give regular statistics of packets forwarded
*/
static int monitor_route(void)
{
unsigned int nr_cpus = bpf_num_possible_cpus();
const unsigned int nr_keys = 256;
struct pollfd fds_route, fds_arp;
__u64 prev[nr_keys][nr_cpus];
struct sockaddr_nl la, lr;
__u64 values[nr_cpus];
struct nlmsghdr *nh;
int nll, ret = 0;
int interval = 5;
__u32 key;
int i;
sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (sock < 0) {
printf("open netlink socket: %s\n", strerror(errno));
return -1;
}
fcntl(sock, F_SETFL, O_NONBLOCK);
memset(&lr, 0, sizeof(lr));
lr.nl_family = AF_NETLINK;
lr.nl_groups = RTMGRP_IPV6_ROUTE | RTMGRP_IPV4_ROUTE | RTMGRP_NOTIFY;
if (bind(sock, (struct sockaddr *)&lr, sizeof(lr)) < 0) {
printf("bind to netlink: %s\n", strerror(errno));
ret = -1;
goto cleanup;
}
fds_route.fd = sock;
fds_route.events = POLL_IN;
sock_arp = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (sock_arp < 0) {
printf("open netlink socket: %s\n", strerror(errno));
return -1;
}
fcntl(sock_arp, F_SETFL, O_NONBLOCK);
memset(&la, 0, sizeof(la));
la.nl_family = AF_NETLINK;
la.nl_groups = RTMGRP_NEIGH | RTMGRP_NOTIFY;
if (bind(sock_arp, (struct sockaddr *)&la, sizeof(la)) < 0) {
printf("bind to netlink: %s\n", strerror(errno));
ret = -1;
goto cleanup;
}
fds_arp.fd = sock_arp;
fds_arp.events = POLL_IN;
memset(prev, 0, sizeof(prev));
do {
signal(SIGINT, close_and_exit);
signal(SIGTERM, close_and_exit);
sleep(interval);
for (key = 0; key < nr_keys; key++) {
__u64 sum = 0;
assert(bpf_map_lookup_elem(rxcnt_map_fd,
&key, values) == 0);
for (i = 0; i < nr_cpus; i++)
sum += (values[i] - prev[key][i]);
if (sum)
printf("proto %u: %10llu pkt/s\n",
key, sum / interval);
memcpy(prev[key], values, sizeof(values));
}
memset(buf, 0, sizeof(buf));
if (poll(&fds_route, 1, 3) == POLL_IN) {
nll = recv_msg(lr, sock);
if (nll < 0) {
printf("recv from netlink: %s\n", strerror(nll));
ret = -1;
goto cleanup;
}
nh = (struct nlmsghdr *)buf;
printf("Routing table updated.\n");
read_route(nh, nll);
}
memset(buf, 0, sizeof(buf));
if (poll(&fds_arp, 1, 3) == POLL_IN) {
nll = recv_msg(la, sock_arp);
if (nll < 0) {
printf("recv from netlink: %s\n", strerror(nll));
ret = -1;
goto cleanup;
}
nh = (struct nlmsghdr *)buf;
read_arp(nh, nll);
}
} while (1);
cleanup:
close(sock);
return ret;
}
static void usage(const char *prog)
{
fprintf(stderr,
"%s: %s [OPTS] interface name list\n\n"
"OPTS:\n"
" -S use skb-mode\n"
" -F force loading prog\n",
__func__, prog);
}
int main(int ac, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
struct bpf_prog_load_attr prog_load_attr = {
.prog_type = BPF_PROG_TYPE_XDP,
};
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
const char *optstr = "SF";
struct bpf_object *obj;
char filename[256];
char **ifname_list;
int prog_fd, opt;
int err, i = 1;
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
prog_load_attr.file = filename;
total_ifindex = ac - 1;
ifname_list = (argv + 1);
while ((opt = getopt(ac, argv, optstr)) != -1) {
switch (opt) {
case 'S':
flags |= XDP_FLAGS_SKB_MODE;
total_ifindex--;
ifname_list++;
break;
case 'F':
flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
total_ifindex--;
ifname_list++;
break;
default:
usage(basename(argv[0]));
return 1;
}
}
if (optind == ac) {
usage(basename(argv[0]));
return 1;
}
if (setrlimit(RLIMIT_MEMLOCK, &r)) {
perror("setrlimit(RLIMIT_MEMLOCK)");
return 1;
}
if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
return 1;
printf("\n**************loading bpf file*********************\n\n\n");
if (!prog_fd) {
printf("bpf_prog_load_xattr: %s\n", strerror(errno));
return 1;
}
lpm_map_fd = bpf_object__find_map_fd_by_name(obj, "lpm_map");
rxcnt_map_fd = bpf_object__find_map_fd_by_name(obj, "rxcnt");
arp_table_map_fd = bpf_object__find_map_fd_by_name(obj, "arp_table");
exact_match_map_fd = bpf_object__find_map_fd_by_name(obj,
"exact_match");
tx_port_map_fd = bpf_object__find_map_fd_by_name(obj, "tx_port");
if (lpm_map_fd < 0 || rxcnt_map_fd < 0 || arp_table_map_fd < 0 ||
exact_match_map_fd < 0 || tx_port_map_fd < 0) {
printf("bpf_object__find_map_fd_by_name failed\n");
return 1;
}
ifindex_list = (int *)calloc(total_ifindex, sizeof(int *));
for (i = 0; i < total_ifindex; i++) {
ifindex_list[i] = if_nametoindex(ifname_list[i]);
if (!ifindex_list[i]) {
printf("Couldn't translate interface name: %s",
strerror(errno));
return 1;
}
}
prog_id_list = (__u32 *)calloc(total_ifindex, sizeof(__u32 *));
for (i = 0; i < total_ifindex; i++) {
if (bpf_set_link_xdp_fd(ifindex_list[i], prog_fd, flags) < 0) {
printf("link set xdp fd failed\n");
int recovery_index = i;
for (i = 0; i < recovery_index; i++)
bpf_set_link_xdp_fd(ifindex_list[i], -1, flags);
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_list[i] = info.id;
memset(&info, 0, sizeof(info));
printf("Attached to %d\n", ifindex_list[i]);
}
signal(SIGINT, int_exit);
signal(SIGTERM, int_exit);
printf("*******************ROUTE TABLE*************************\n\n\n");
get_route_table(AF_INET);
printf("*******************ARP TABLE***************************\n\n\n");
get_arp_table(AF_INET);
if (monitor_route() < 0) {
printf("Error in receiving route update");
return 1;
}
return 0;
}
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