samples/bpf/xdp_router_ipv4_user.c

   1 /* Copyright (C) 2017 Cavium, Inc.
   2  *
   3  * This program is free software; you can redistribute it and/or modify it
   4  * under the terms of version 2 of the GNU General Public License
   5  * as published by the Free Software Foundation.
   6  */
   7 #include <linux/bpf.h>
   8 #include <linux/netlink.h>
   9 #include <linux/rtnetlink.h>
  10 #include <assert.h>
  11 #include <errno.h>
  12 #include <signal.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <sys/socket.h>
  17 #include <unistd.h>
  18 #include "bpf_load.h"
  19 #include <bpf/bpf.h>
  20 #include <arpa/inet.h>
  21 #include <fcntl.h>
  22 #include <poll.h>
  23 #include <net/if.h>
  24 #include <netdb.h>
  25 #include <sys/ioctl.h>
  26 #include <sys/syscall.h>
  27 #include "bpf_util.h"
  28
  29 int sock, sock_arp, flags = 0;
  30 static int total_ifindex;
  31 int *ifindex_list;
  32 char buf[8192];
  33
  34 static int get_route_table(int rtm_family);
  35 static void int_exit(int sig)
  36 {
  37         int i = 0;
  38
  39         for (i = 0; i < total_ifindex; i++)
  40                 bpf_set_link_xdp_fd(ifindex_list[i], -1, flags);
  41         exit(0);
  42 }
  43
  44 static void close_and_exit(int sig)
  45 {
  46         int i = 0;
  47
  48         close(sock);
  49         close(sock_arp);
  50
  51         for (i = 0; i < total_ifindex; i++)
  52                 bpf_set_link_xdp_fd(ifindex_list[i], -1, flags);
  53         exit(0);
  54 }
  55
  56 /* Get the mac address of the interface given interface name */
  57 static __be64 getmac(char *iface)
  58 {
  59         struct ifreq ifr;
  60         __be64 mac = 0;
  61         int fd, i;
  62
  63         fd = socket(AF_INET, SOCK_DGRAM, 0);
  64         ifr.ifr_addr.sa_family = AF_INET;
  65         strncpy(ifr.ifr_name, iface, IFNAMSIZ - 1);
  66         if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0) {
  67                 printf("ioctl failed leaving....\n");
  68                 return -1;
  69         }
  70         for (i = 0; i < 6 ; i++)
  71                 *((__u8 *)&mac + i) = (__u8)ifr.ifr_hwaddr.sa_data[i];
  72         close(fd);
  73         return mac;
  74 }
  75
  76 static int recv_msg(struct sockaddr_nl sock_addr, int sock)
  77 {
  78         struct nlmsghdr *nh;
  79         int len, nll = 0;
  80         char *buf_ptr;
  81
  82         buf_ptr = buf;
  83         while (1) {
  84                 len = recv(sock, buf_ptr, sizeof(buf) - nll, 0);
  85                 if (len < 0)
  86                         return len;
  87
  88                 nh = (struct nlmsghdr *)buf_ptr;
  89
  90                 if (nh->nlmsg_type == NLMSG_DONE)
  91                         break;
  92                 buf_ptr += len;
  93                 nll += len;
  94                 if ((sock_addr.nl_groups & RTMGRP_NEIGH) == RTMGRP_NEIGH)
  95                         break;
  96
  97                 if ((sock_addr.nl_groups & RTMGRP_IPV4_ROUTE) == RTMGRP_IPV4_ROUTE)
  98                         break;
  99         }
 100         return nll;
 101 }
 102
 103 /* Function to parse the route entry returned by netlink
 104  * Updates the route entry related map entries
 105  */
 106 static void read_route(struct nlmsghdr *nh, int nll)
 107 {
 108         char dsts[24], gws[24], ifs[16], dsts_len[24], metrics[24];
 109         struct bpf_lpm_trie_key *prefix_key;
 110         struct rtattr *rt_attr;
 111         struct rtmsg *rt_msg;
 112         int rtm_family;
 113         int rtl;
 114         int i;
 115         struct route_table {
 116                 int  dst_len, iface, metric;
 117                 char *iface_name;
 118                 __be32 dst, gw;
 119                 __be64 mac;
 120         } route;
 121         struct arp_table {
 122                 __be64 mac;
 123                 __be32 dst;
 124         };
 125
 126         struct direct_map {
 127                 struct arp_table arp;
 128                 int ifindex;
 129                 __be64 mac;
 130         } direct_entry;
 131
 132         if (nh->nlmsg_type == RTM_DELROUTE)
 133                 printf("DELETING Route entry\n");
 134         else if (nh->nlmsg_type == RTM_GETROUTE)
 135                 printf("READING Route entry\n");
 136         else if (nh->nlmsg_type == RTM_NEWROUTE)
 137                 printf("NEW Route entry\n");
 138         else
 139                 printf("%d\n", nh->nlmsg_type);
 140
 141         memset(&route, 0, sizeof(route));
 142         printf("Destination\t\tGateway\t\tGenmask\t\tMetric\t\tIface\n");
 143         for (; NLMSG_OK(nh, nll); nh = NLMSG_NEXT(nh, nll)) {
 144                 rt_msg = (struct rtmsg *)NLMSG_DATA(nh);
 145                 rtm_family = rt_msg->rtm_family;
 146                 if (rtm_family == AF_INET)
 147                         if (rt_msg->rtm_table != RT_TABLE_MAIN)
 148                                 continue;
 149                 rt_attr = (struct rtattr *)RTM_RTA(rt_msg);
 150                 rtl = RTM_PAYLOAD(nh);
 151
 152                 for (; RTA_OK(rt_attr, rtl); rt_attr = RTA_NEXT(rt_attr, rtl)) {
 153                         switch (rt_attr->rta_type) {
 154                         case NDA_DST:
 155                                 sprintf(dsts, "%u",
 156                                         (*((__be32 *)RTA_DATA(rt_attr))));
 157                                 break;
 158                         case RTA_GATEWAY:
 159                                 sprintf(gws, "%u",
 160                                         *((__be32 *)RTA_DATA(rt_attr)));
 161                                 break;
 162                         case RTA_OIF:
 163                                 sprintf(ifs, "%u",
 164                                         *((int *)RTA_DATA(rt_attr)));
 165                                 break;
 166                         case RTA_METRICS:
 167                                 sprintf(metrics, "%u",
 168                                         *((int *)RTA_DATA(rt_attr)));
 169                         default:
 170                                 break;
 171                         }
 172                 }
 173                 sprintf(dsts_len, "%d", rt_msg->rtm_dst_len);
 174                 route.dst = atoi(dsts);
 175                 route.dst_len = atoi(dsts_len);
 176                 route.gw = atoi(gws);
 177                 route.iface = atoi(ifs);
 178                 route.metric = atoi(metrics);
 179                 route.iface_name = alloca(sizeof(char *) * IFNAMSIZ);
 180                 route.iface_name = if_indextoname(route.iface, route.iface_name);
 181                 route.mac = getmac(route.iface_name);
 182                 if (route.mac == -1) {
 183                         int i = 0;
 184
 185                         for (i = 0; i < total_ifindex; i++)
 186                                 bpf_set_link_xdp_fd(ifindex_list[i], -1, flags);
 187                         exit(0);
 188                 }
 189                 assert(bpf_map_update_elem(map_fd[4], &route.iface, &route.iface, 0) == 0);
 190                 if (rtm_family == AF_INET) {
 191                         struct trie_value {
 192                                 __u8 prefix[4];
 193                                 __be64 value;
 194                                 int ifindex;
 195                                 int metric;
 196                                 __be32 gw;
 197                         } *prefix_value;
 198
 199                         prefix_key = alloca(sizeof(*prefix_key) + 3);
 200                         prefix_value = alloca(sizeof(*prefix_value));
 201
 202                         prefix_key->prefixlen = 32;
 203                         prefix_key->prefixlen = route.dst_len;
 204                         direct_entry.mac = route.mac & 0xffffffffffff;
 205                         direct_entry.ifindex = route.iface;
 206                         direct_entry.arp.mac = 0;
 207                         direct_entry.arp.dst = 0;
 208                         if (route.dst_len == 32) {
 209                                 if (nh->nlmsg_type == RTM_DELROUTE) {
 210                                         assert(bpf_map_delete_elem(map_fd[3], &route.dst) == 0);
 211                                 } else {
 212                                         if (bpf_map_lookup_elem(map_fd[2], &route.dst, &direct_entry.arp.mac) == 0)
 213                                                 direct_entry.arp.dst = route.dst;
 214                                         assert(bpf_map_update_elem(map_fd[3], &route.dst, &direct_entry, 0) == 0);
 215                                 }
 216                         }
 217                         for (i = 0; i < 4; i++)
 218                                 prefix_key->data[i] = (route.dst >> i * 8) & 0xff;
 219
 220                         printf("%3d.%d.%d.%d\t\t%3x\t\t%d\t\t%d\t\t%s\n",
 221                                (int)prefix_key->data[0],
 222                                (int)prefix_key->data[1],
 223                                (int)prefix_key->data[2],
 224                                (int)prefix_key->data[3],
 225                                route.gw, route.dst_len,
 226                                route.metric,
 227                                route.iface_name);
 228                         if (bpf_map_lookup_elem(map_fd[0], prefix_key,
 229                                                 prefix_value) < 0) {
 230                                 for (i = 0; i < 4; i++)
 231                                         prefix_value->prefix[i] = prefix_key->data[i];
 232                                 prefix_value->value = route.mac & 0xffffffffffff;
 233                                 prefix_value->ifindex = route.iface;
 234                                 prefix_value->gw = route.gw;
 235                                 prefix_value->metric = route.metric;
 236
 237                                 assert(bpf_map_update_elem(map_fd[0],
 238                                                            prefix_key,
 239                                                            prefix_value, 0
 240                                                            ) == 0);
 241                         } else {
 242                                 if (nh->nlmsg_type == RTM_DELROUTE) {
 243                                         printf("deleting entry\n");
 244                                         printf("prefix key=%d.%d.%d.%d/%d",
 245                                                prefix_key->data[0],
 246                                                prefix_key->data[1],
 247                                                prefix_key->data[2],
 248                                                prefix_key->data[3],
 249                                                prefix_key->prefixlen);
 250                                         assert(bpf_map_delete_elem(map_fd[0],
 251                                                                    prefix_key
 252                                                                    ) == 0);
 253                                         /* Rereading the route table to check if
 254                                          * there is an entry with the same
 255                                          * prefix but a different metric as the
 256                                          * deleted enty.
 257                                          */
 258                                         get_route_table(AF_INET);
 259                                 } else if (prefix_key->data[0] ==
 260                                            prefix_value->prefix[0] &&
 261                                            prefix_key->data[1] ==
 262                                            prefix_value->prefix[1] &&
 263                                            prefix_key->data[2] ==
 264                                            prefix_value->prefix[2] &&
 265                                            prefix_key->data[3] ==
 266                                            prefix_value->prefix[3] &&
 267                                            route.metric >= prefix_value->metric) {
 268                                         continue;
 269                                 } else {
 270                                         for (i = 0; i < 4; i++)
 271                                                 prefix_value->prefix[i] =
 272                                                         prefix_key->data[i];
 273                                         prefix_value->value =
 274                                                 route.mac & 0xffffffffffff;
 275                                         prefix_value->ifindex = route.iface;
 276                                         prefix_value->gw = route.gw;
 277                                         prefix_value->metric = route.metric;
 278                                         assert(bpf_map_update_elem(
 279                                                                    map_fd[0],
 280                                                                    prefix_key,
 281                                                                    prefix_value,
 282                                                                    0) == 0);
 283                                 }
 284                         }
 285                 }
 286                 memset(&route, 0, sizeof(route));
 287                 memset(dsts, 0, sizeof(dsts));
 288                 memset(dsts_len, 0, sizeof(dsts_len));
 289                 memset(gws, 0, sizeof(gws));
 290                 memset(ifs, 0, sizeof(ifs));
 291                 memset(&route, 0, sizeof(route));
 292         }
 293 }
 294
 295 /* Function to read the existing route table  when the process is launched*/
 296 static int get_route_table(int rtm_family)
 297 {
 298         struct sockaddr_nl sa;
 299         struct nlmsghdr *nh;
 300         int sock, seq = 0;
 301         struct msghdr msg;
 302         struct iovec iov;
 303         int ret = 0;
 304         int nll;
 305
 306         struct {
 307                 struct nlmsghdr nl;
 308                 struct rtmsg rt;
 309                 char buf[8192];
 310         } req;
 311
 312         sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
 313         if (sock < 0) {
 314                 printf("open netlink socket: %s\n", strerror(errno));
 315                 return -1;
 316         }
 317         memset(&sa, 0, sizeof(sa));
 318         sa.nl_family = AF_NETLINK;
 319         if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
 320                 printf("bind to netlink: %s\n", strerror(errno));
 321                 ret = -1;
 322                 goto cleanup;
 323         }
 324         memset(&req, 0, sizeof(req));
 325         req.nl.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
 326         req.nl.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
 327         req.nl.nlmsg_type = RTM_GETROUTE;
 328
 329         req.rt.rtm_family = rtm_family;
 330         req.rt.rtm_table = RT_TABLE_MAIN;
 331         req.nl.nlmsg_pid = 0;
 332         req.nl.nlmsg_seq = ++seq;
 333         memset(&msg, 0, sizeof(msg));
 334         iov.iov_base = (void *)&req.nl;
 335         iov.iov_len = req.nl.nlmsg_len;
 336         msg.msg_iov = &iov;
 337         msg.msg_iovlen = 1;
 338         ret = sendmsg(sock, &msg, 0);
 339         if (ret < 0) {
 340                 printf("send to netlink: %s\n", strerror(errno));
 341                 ret = -1;
 342                 goto cleanup;
 343         }
 344         memset(buf, 0, sizeof(buf));
 345         nll = recv_msg(sa, sock);
 346         if (nll < 0) {
 347                 printf("recv from netlink: %s\n", strerror(nll));
 348                 ret = -1;
 349                 goto cleanup;
 350         }
 351         nh = (struct nlmsghdr *)buf;
 352         read_route(nh, nll);
 353 cleanup:
 354         close(sock);
 355         return ret;
 356 }
 357
 358 /* Function to parse the arp entry returned by netlink
 359  * Updates the arp entry related map entries
 360  */
 361 static void read_arp(struct nlmsghdr *nh, int nll)
 362 {
 363         struct rtattr *rt_attr;
 364         char dsts[24], mac[24];
 365         struct ndmsg *rt_msg;
 366         int rtl, ndm_family;
 367
 368         struct arp_table {
 369                 __be64 mac;
 370                 __be32 dst;
 371         } arp_entry;
 372         struct direct_map {
 373                 struct arp_table arp;
 374                 int ifindex;
 375                 __be64 mac;
 376         } direct_entry;
 377
 378         if (nh->nlmsg_type == RTM_GETNEIGH)
 379                 printf("READING arp entry\n");
 380         printf("Address\tHwAddress\n");
 381         for (; NLMSG_OK(nh, nll); nh = NLMSG_NEXT(nh, nll)) {
 382                 rt_msg = (struct ndmsg *)NLMSG_DATA(nh);
 383                 rt_attr = (struct rtattr *)RTM_RTA(rt_msg);
 384                 ndm_family = rt_msg->ndm_family;
 385                 rtl = RTM_PAYLOAD(nh);
 386                 for (; RTA_OK(rt_attr, rtl); rt_attr = RTA_NEXT(rt_attr, rtl)) {
 387                         switch (rt_attr->rta_type) {
 388                         case NDA_DST:
 389                                 sprintf(dsts, "%u",
 390                                         *((__be32 *)RTA_DATA(rt_attr)));
 391                                 break;
 392                         case NDA_LLADDR:
 393                                 sprintf(mac, "%lld",
 394                                         *((__be64 *)RTA_DATA(rt_attr)));
 395                                 break;
 396                         default:
 397                                 break;
 398                         }
 399                 }
 400                 arp_entry.dst = atoi(dsts);
 401                 arp_entry.mac = atol(mac);
 402                 printf("%x\t\t%llx\n", arp_entry.dst, arp_entry.mac);
 403                 if (ndm_family == AF_INET) {
 404                         if (bpf_map_lookup_elem(map_fd[3], &arp_entry.dst,
 405                                                 &direct_entry) == 0) {
 406                                 if (nh->nlmsg_type == RTM_DELNEIGH) {
 407                                         direct_entry.arp.dst = 0;
 408                                         direct_entry.arp.mac = 0;
 409                                 } else if (nh->nlmsg_type == RTM_NEWNEIGH) {
 410                                         direct_entry.arp.dst = arp_entry.dst;
 411                                         direct_entry.arp.mac = arp_entry.mac;
 412                                 }
 413                                 assert(bpf_map_update_elem(map_fd[3],
 414                                                            &arp_entry.dst,
 415                                                            &direct_entry, 0
 416                                                            ) == 0);
 417                                 memset(&direct_entry, 0, sizeof(direct_entry));
 418                         }
 419                         if (nh->nlmsg_type == RTM_DELNEIGH) {
 420                                 assert(bpf_map_delete_elem(map_fd[2], &arp_entry.dst) == 0);
 421                         } else if (nh->nlmsg_type == RTM_NEWNEIGH) {
 422                                 assert(bpf_map_update_elem(map_fd[2],
 423                                                            &arp_entry.dst,
 424                                                            &arp_entry.mac, 0
 425                                                            ) == 0);
 426                         }
 427                 }
 428                 memset(&arp_entry, 0, sizeof(arp_entry));
 429                 memset(dsts, 0, sizeof(dsts));
 430         }
 431 }
 432
 433 /* Function to read the existing arp table  when the process is launched*/
 434 static int get_arp_table(int rtm_family)
 435 {
 436         struct sockaddr_nl sa;
 437         struct nlmsghdr *nh;
 438         int sock, seq = 0;
 439         struct msghdr msg;
 440         struct iovec iov;
 441         int ret = 0;
 442         int nll;
 443         struct {
 444                 struct nlmsghdr nl;
 445                 struct ndmsg rt;
 446                 char buf[8192];
 447         } req;
 448
 449         sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
 450         if (sock < 0) {
 451                 printf("open netlink socket: %s\n", strerror(errno));
 452                 return -1;
 453         }
 454         memset(&sa, 0, sizeof(sa));
 455         sa.nl_family = AF_NETLINK;
 456         if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
 457                 printf("bind to netlink: %s\n", strerror(errno));
 458                 ret = -1;
 459                 goto cleanup;
 460         }
 461         memset(&req, 0, sizeof(req));
 462         req.nl.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
 463         req.nl.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
 464         req.nl.nlmsg_type = RTM_GETNEIGH;
 465         req.rt.ndm_state = NUD_REACHABLE;
 466         req.rt.ndm_family = rtm_family;
 467         req.nl.nlmsg_pid = 0;
 468         req.nl.nlmsg_seq = ++seq;
 469         memset(&msg, 0, sizeof(msg));
 470         iov.iov_base = (void *)&req.nl;
 471         iov.iov_len = req.nl.nlmsg_len;
 472         msg.msg_iov = &iov;
 473         msg.msg_iovlen = 1;
 474         ret = sendmsg(sock, &msg, 0);
 475         if (ret < 0) {
 476                 printf("send to netlink: %s\n", strerror(errno));
 477                 ret = -1;
 478                 goto cleanup;
 479         }
 480         memset(buf, 0, sizeof(buf));
 481         nll = recv_msg(sa, sock);
 482         if (nll < 0) {
 483                 printf("recv from netlink: %s\n", strerror(nll));
 484                 ret = -1;
 485                 goto cleanup;
 486         }
 487         nh = (struct nlmsghdr *)buf;
 488         read_arp(nh, nll);
 489 cleanup:
 490         close(sock);
 491         return ret;
 492 }
 493
 494 /* Function to keep track and update changes in route and arp table
 495  * Give regular statistics of packets forwarded
 496  */
 497 static int monitor_route(void)
 498 {
 499         unsigned int nr_cpus = bpf_num_possible_cpus();
 500         const unsigned int nr_keys = 256;
 501         struct pollfd fds_route, fds_arp;
 502         __u64 prev[nr_keys][nr_cpus];
 503         struct sockaddr_nl la, lr;
 504         __u64 values[nr_cpus];
 505         struct nlmsghdr *nh;
 506         int nll, ret = 0;
 507         int interval = 5;
 508         __u32 key;
 509         int i;
 510
 511         sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
 512         if (sock < 0) {
 513                 printf("open netlink socket: %s\n", strerror(errno));
 514                 return -1;
 515         }
 516
 517         fcntl(sock, F_SETFL, O_NONBLOCK);
 518         memset(&lr, 0, sizeof(lr));
 519         lr.nl_family = AF_NETLINK;
 520         lr.nl_groups = RTMGRP_IPV6_ROUTE | RTMGRP_IPV4_ROUTE | RTMGRP_NOTIFY;
 521         if (bind(sock, (struct sockaddr *)&lr, sizeof(lr)) < 0) {
 522                 printf("bind to netlink: %s\n", strerror(errno));
 523                 ret = -1;
 524                 goto cleanup;
 525         }
 526         fds_route.fd = sock;
 527         fds_route.events = POLL_IN;
 528
 529         sock_arp = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
 530         if (sock_arp < 0) {
 531                 printf("open netlink socket: %s\n", strerror(errno));
 532                 return -1;
 533         }
 534
 535         fcntl(sock_arp, F_SETFL, O_NONBLOCK);
 536         memset(&la, 0, sizeof(la));
 537         la.nl_family = AF_NETLINK;
 538         la.nl_groups = RTMGRP_NEIGH | RTMGRP_NOTIFY;
 539         if (bind(sock_arp, (struct sockaddr *)&la, sizeof(la)) < 0) {
 540                 printf("bind to netlink: %s\n", strerror(errno));
 541                 ret = -1;
 542                 goto cleanup;
 543         }
 544         fds_arp.fd = sock_arp;
 545         fds_arp.events = POLL_IN;
 546
 547         memset(prev, 0, sizeof(prev));
 548         do {
 549                 signal(SIGINT, close_and_exit);
 550                 signal(SIGTERM, close_and_exit);
 551
 552                 sleep(interval);
 553                 for (key = 0; key < nr_keys; key++) {
 554                         __u64 sum = 0;
 555
 556                         assert(bpf_map_lookup_elem(map_fd[1], &key, values) == 0);
 557                         for (i = 0; i < nr_cpus; i++)
 558                                 sum += (values[i] - prev[key][i]);
 559                         if (sum)
 560                                 printf("proto %u: %10llu pkt/s\n",
 561                                        key, sum / interval);
 562                         memcpy(prev[key], values, sizeof(values));
 563                 }
 564
 565                 memset(buf, 0, sizeof(buf));
 566                 if (poll(&fds_route, 1, 3) == POLL_IN) {
 567                         nll = recv_msg(lr, sock);
 568                         if (nll < 0) {
 569                                 printf("recv from netlink: %s\n", strerror(nll));
 570                                 ret = -1;
 571                                 goto cleanup;
 572                         }
 573
 574                         nh = (struct nlmsghdr *)buf;
 575                         printf("Routing table updated.\n");
 576                         read_route(nh, nll);
 577                 }
 578                 memset(buf, 0, sizeof(buf));
 579                 if (poll(&fds_arp, 1, 3) == POLL_IN) {
 580                         nll = recv_msg(la, sock_arp);
 581                         if (nll < 0) {
 582                                 printf("recv from netlink: %s\n", strerror(nll));
 583                                 ret = -1;
 584                                 goto cleanup;
 585                         }
 586
 587                         nh = (struct nlmsghdr *)buf;
 588                         read_arp(nh, nll);
 589                 }
 590
 591         } while (1);
 592 cleanup:
 593         close(sock);
 594         return ret;
 595 }
 596
 597 int main(int ac, char **argv)
 598 {
 599         char filename[256];
 600         char **ifname_list;
 601         int i = 1;
 602
 603         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 604         if (ac < 2) {
 605                 printf("usage: %s [-S] Interface name list\n", argv[0]);
 606                 return 1;
 607         }
 608         if (!strcmp(argv[1], "-S")) {
 609                 flags = XDP_FLAGS_SKB_MODE;
 610                 total_ifindex = ac - 2;
 611                 ifname_list = (argv + 2);
 612         } else {
 613                 flags = 0;
 614                 total_ifindex = ac - 1;
 615                 ifname_list = (argv + 1);
 616         }
 617         if (load_bpf_file(filename)) {
 618                 printf("%s", bpf_log_buf);
 619                 return 1;
 620         }
 621         printf("\n**************loading bpf file*********************\n\n\n");
 622         if (!prog_fd[0]) {
 623                 printf("load_bpf_file: %s\n", strerror(errno));
 624                 return 1;
 625         }
 626         ifindex_list = (int *)malloc(total_ifindex * sizeof(int *));
 627         for (i = 0; i < total_ifindex; i++) {
 628                 ifindex_list[i] = if_nametoindex(ifname_list[i]);
 629                 if (!ifindex_list[i]) {
 630                         printf("Couldn't translate interface name: %s",
 631                                strerror(errno));
 632                         return 1;
 633                 }
 634         }
 635         for (i = 0; i < total_ifindex; i++) {
 636                 if (bpf_set_link_xdp_fd(ifindex_list[i], prog_fd[0], flags) < 0) {
 637                         printf("link set xdp fd failed\n");
 638                         int recovery_index = i;
 639
 640                         for (i = 0; i < recovery_index; i++)
 641                                 bpf_set_link_xdp_fd(ifindex_list[i], -1, flags);
 642
 643                         return 1;
 644                 }
 645                 printf("Attached to %d\n", ifindex_list[i]);
 646         }
 647         signal(SIGINT, int_exit);
 648         signal(SIGTERM, int_exit);
 649
 650         printf("*******************ROUTE TABLE*************************\n\n\n");
 651         get_route_table(AF_INET);
 652         printf("*******************ARP TABLE***************************\n\n\n");
 653         get_arp_table(AF_INET);
 654         if (monitor_route() < 0) {
 655                 printf("Error in receiving route update");
 656                 return 1;
 657         }
 658
 659         return 0;
 660 }