ip/iplink.c

   1 /*
   2  * iplink.c             "ip link".
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  *
  11  */
  12
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <unistd.h>
  16 #include <syslog.h>
  17 #include <fcntl.h>
  18 #include <errno.h>
  19 #include <sys/socket.h>
  20 #include <linux/if.h>
  21 #include <linux/if_packet.h>
  22 #include <linux/if_ether.h>
  23 #include <linux/sockios.h>
  24 #include <netinet/in.h>
  25 #include <arpa/inet.h>
  26 #include <string.h>
  27 #include <sys/ioctl.h>
  28 #include <linux/sockios.h>
  29
  30 #include "rt_names.h"
  31 #include "utils.h"
  32 #include "ip_common.h"
  33
  34
  35 static void usage(void) __attribute__((noreturn));
  36
  37 void iplink_usage(void)
  38 {
  39         fprintf(stderr, "Usage: ip link set DEVICE { up | down | arp { on | off } |\n");
  40         fprintf(stderr, "                            dynamic { on | off } |\n");
  41         fprintf(stderr, "                            multicast { on | off } | txqueuelen PACKETS |\n");
  42         fprintf(stderr, "                            name NEWNAME |\n");
  43         fprintf(stderr, "                            address LLADDR | broadcast LLADDR |\n");
  44         fprintf(stderr, "                            mtu MTU }\n");
  45         fprintf(stderr, "       ip link show [ DEVICE ]\n");
  46         exit(-1);
  47 }
  48
  49 static void usage(void)
  50 {
  51         iplink_usage();
  52 }
  53
  54 static int on_off(char *msg)
  55 {
  56         fprintf(stderr, "Error: argument of \"%s\" must be \"on\" or \"off\"\n", msg);
  57         return -1;
  58 }
  59
  60 static int get_ctl_fd(void)
  61 {
  62         int s_errno;
  63         int fd;
  64
  65         fd = socket(PF_INET, SOCK_DGRAM, 0);
  66         if (fd >= 0)
  67                 return fd;
  68         s_errno = errno;
  69         fd = socket(PF_PACKET, SOCK_DGRAM, 0);
  70         if (fd >= 0)
  71                 return fd;
  72         fd = socket(PF_INET6, SOCK_DGRAM, 0);
  73         if (fd >= 0)
  74                 return fd;
  75         errno = s_errno;
  76         perror("Cannot create control socket");
  77         return -1;
  78 }
  79
  80 static int do_chflags(char *dev, __u32 flags, __u32 mask)
  81 {
  82         struct ifreq ifr;
  83         int fd;
  84         int err;
  85
  86         strcpy(ifr.ifr_name, dev);
  87         fd = get_ctl_fd();
  88         if (fd < 0)
  89                 return -1;
  90         err = ioctl(fd, SIOCGIFFLAGS, &ifr);
  91         if (err) {
  92                 perror("SIOCGIFFLAGS");
  93                 close(fd);
  94                 return -1;
  95         }
  96         if ((ifr.ifr_flags^flags)&mask) {
  97                 ifr.ifr_flags &= ~mask;
  98                 ifr.ifr_flags |= mask&flags;
  99                 err = ioctl(fd, SIOCSIFFLAGS, &ifr);
 100                 if (err)
 101                         perror("SIOCSIFFLAGS");
 102         }
 103         close(fd);
 104         return err;
 105 }
 106
 107 static int do_changename(char *dev, char *newdev)
 108 {
 109         struct ifreq ifr;
 110         int fd;
 111         int err;
 112
 113         strcpy(ifr.ifr_name, dev);
 114         strcpy(ifr.ifr_newname, newdev);
 115         fd = get_ctl_fd();
 116         if (fd < 0)
 117                 return -1;
 118         err = ioctl(fd, SIOCSIFNAME, &ifr);
 119         if (err) {
 120                 perror("SIOCSIFNAME");
 121                 close(fd);
 122                 return -1;
 123         }
 124         close(fd);
 125         return err;
 126 }
 127
 128 static int set_qlen(char *dev, int qlen)
 129 {
 130         struct ifreq ifr;
 131         int s;
 132
 133         s = get_ctl_fd();
 134         if (s < 0)
 135                 return -1;
 136
 137         memset(&ifr, 0, sizeof(ifr));
 138         strcpy(ifr.ifr_name, dev);
 139         ifr.ifr_qlen = qlen;
 140         if (ioctl(s, SIOCSIFTXQLEN, &ifr) < 0) {
 141                 perror("SIOCSIFXQLEN");
 142                 close(s);
 143                 return -1;
 144         }
 145         close(s);
 146
 147         return 0;
 148 }
 149
 150 static int set_mtu(char *dev, int mtu)
 151 {
 152         struct ifreq ifr;
 153         int s;
 154
 155         s = get_ctl_fd();
 156         if (s < 0)
 157                 return -1;
 158
 159         memset(&ifr, 0, sizeof(ifr));
 160         strcpy(ifr.ifr_name, dev);
 161         ifr.ifr_mtu = mtu;
 162         if (ioctl(s, SIOCSIFMTU, &ifr) < 0) {
 163                 perror("SIOCSIFMTU");
 164                 close(s);
 165                 return -1;
 166         }
 167         close(s);
 168
 169         return 0;
 170 }
 171
 172 static int get_address(char *dev, int *htype)
 173 {
 174         struct ifreq ifr;
 175         struct sockaddr_ll me;
 176         int alen;
 177         int s;
 178
 179         s = socket(PF_PACKET, SOCK_DGRAM, 0);
 180         if (s < 0) {
 181                 perror("socket(PF_PACKET)");
 182                 return -1;
 183         }
 184
 185         memset(&ifr, 0, sizeof(ifr));
 186         strcpy(ifr.ifr_name, dev);
 187         if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
 188                 perror("SIOCGIFINDEX");
 189                 close(s);
 190                 return -1;
 191         }
 192
 193         memset(&me, 0, sizeof(me));
 194         me.sll_family = AF_PACKET;
 195         me.sll_ifindex = ifr.ifr_ifindex;
 196         me.sll_protocol = htons(ETH_P_LOOP);
 197         if (bind(s, (struct sockaddr*)&me, sizeof(me)) == -1) {
 198                 perror("bind");
 199                 close(s);
 200                 return -1;
 201         }
 202
 203         alen = sizeof(me);
 204         if (getsockname(s, (struct sockaddr*)&me, &alen) == -1) {
 205                 perror("getsockname");
 206                 close(s);
 207                 return -1;
 208         }
 209         close(s);
 210         *htype = me.sll_hatype;
 211         return me.sll_halen;
 212 }
 213
 214 static int parse_address(char *dev, int hatype, int halen, char *lla, struct ifreq *ifr)
 215 {
 216         int alen;
 217
 218         memset(ifr, 0, sizeof(*ifr));
 219         strcpy(ifr->ifr_name, dev);
 220         ifr->ifr_hwaddr.sa_family = hatype;
 221         alen = ll_addr_a2n(ifr->ifr_hwaddr.sa_data, 14, lla);
 222         if (alen < 0)
 223                 return -1;
 224         if (alen != halen) {
 225                 fprintf(stderr, "Wrong address (%s) length: expected %d bytes\n", lla, halen);
 226                 return -1;
 227         }
 228         return 0;
 229 }
 230
 231 static int set_address(struct ifreq *ifr, int brd)
 232 {
 233         int s;
 234
 235         s = get_ctl_fd();
 236         if (s < 0)
 237                 return -1;
 238         if (ioctl(s, brd?SIOCSIFHWBROADCAST:SIOCSIFHWADDR, ifr) < 0) {
 239                 perror(brd?"SIOCSIFHWBROADCAST":"SIOCSIFHWADDR");
 240                 close(s);
 241                 return -1;
 242         }
 243         close(s);
 244         return 0;
 245 }
 246
 247
 248 static int do_set(int argc, char **argv)
 249 {
 250         char *dev = NULL;
 251         __u32 mask = 0;
 252         __u32 flags = 0;
 253         int qlen = -1;
 254         int mtu = -1;
 255         char *newaddr = NULL;
 256         char *newbrd = NULL;
 257         struct ifreq ifr0, ifr1;
 258         char *newname = NULL;
 259         int htype, halen;
 260
 261         while (argc > 0) {
 262                 if (strcmp(*argv, "up") == 0) {
 263                         mask |= IFF_UP;
 264                         flags |= IFF_UP;
 265                 } else if (strcmp(*argv, "down") == 0) {
 266                         mask |= IFF_UP;
 267                         flags &= ~IFF_UP;
 268                 } else if (strcmp(*argv, "name") == 0) {
 269                         NEXT_ARG();
 270                         newname = *argv;
 271                 } else if (matches(*argv, "address") == 0) {
 272                         NEXT_ARG();
 273                         newaddr = *argv;
 274                 } else if (matches(*argv, "broadcast") == 0 ||
 275                            strcmp(*argv, "brd") == 0) {
 276                         NEXT_ARG();
 277                         newbrd = *argv;
 278                 } else if (matches(*argv, "txqueuelen") == 0 ||
 279                            strcmp(*argv, "qlen") == 0 ||
 280                            matches(*argv, "txqlen") == 0) {
 281                         NEXT_ARG();
 282                         if (qlen != -1)
 283                                 duparg("txqueuelen", *argv);
 284                         if (get_integer(&qlen,  *argv, 0))
 285                                 invarg("Invalid \"txqueuelen\" value\n", *argv);
 286                 } else if (strcmp(*argv, "mtu") == 0) {
 287                         NEXT_ARG();
 288                         if (mtu != -1)
 289                                 duparg("mtu", *argv);
 290                         if (get_integer(&mtu, *argv, 0))
 291                                 invarg("Invalid \"mtu\" value\n", *argv);
 292                 } else if (strcmp(*argv, "multicast") == 0) {
 293                         NEXT_ARG();
 294                         mask |= IFF_MULTICAST;
 295                         if (strcmp(*argv, "on") == 0) {
 296                                 flags |= IFF_MULTICAST;
 297                         } else if (strcmp(*argv, "off") == 0) {
 298                                 flags &= ~IFF_MULTICAST;
 299                         } else
 300                                 return on_off("multicast");
 301                 } else if (strcmp(*argv, "arp") == 0) {
 302                         NEXT_ARG();
 303                         mask |= IFF_NOARP;
 304                         if (strcmp(*argv, "on") == 0) {
 305                                 flags &= ~IFF_NOARP;
 306                         } else if (strcmp(*argv, "off") == 0) {
 307                                 flags |= IFF_NOARP;
 308                         } else
 309                                 return on_off("noarp");
 310 #ifdef IFF_DYNAMIC
 311                 } else if (matches(*argv, "dynamic") == 0) {
 312                         NEXT_ARG();
 313                         mask |= IFF_DYNAMIC;
 314                         if (strcmp(*argv, "on") == 0) {
 315                                 flags |= IFF_DYNAMIC;
 316                         } else if (strcmp(*argv, "off") == 0) {
 317                                 flags &= ~IFF_DYNAMIC;
 318                         } else
 319                                 return on_off("dynamic");
 320 #endif
 321                 } else {
 322                         if (strcmp(*argv, "dev") == 0) {
 323                                 NEXT_ARG();
 324                         }
 325                         if (matches(*argv, "help") == 0)
 326                                 usage();
 327                         if (dev)
 328                                 duparg2("dev", *argv);
 329                         dev = *argv;
 330                 }
 331                 argc--; argv++;
 332         }
 333
 334         if (!dev) {
 335                 fprintf(stderr, "Not enough of information: \"dev\" argument is required.\n");
 336                 exit(-1);
 337         }
 338
 339         if (newaddr || newbrd) {
 340                 halen = get_address(dev, &htype);
 341                 if (halen < 0)
 342                         return -1;
 343                 if (newaddr) {
 344                         if (parse_address(dev, htype, halen, newaddr, &ifr0) < 0)
 345                                 return -1;
 346                 }
 347                 if (newbrd) {
 348                         if (parse_address(dev, htype, halen, newbrd, &ifr1) < 0)
 349                                 return -1;
 350                 }
 351         }
 352
 353         if (newname && strcmp(dev, newname)) {
 354                 if (do_changename(dev, newname) < 0)
 355                         return -1;
 356                 dev = newname;
 357         }
 358         if (qlen != -1) {
 359                 if (set_qlen(dev, qlen) < 0)
 360                         return -1;
 361         }
 362         if (mtu != -1) {
 363                 if (set_mtu(dev, mtu) < 0)
 364                         return -1;
 365         }
 366         if (newaddr || newbrd) {
 367                 if (newbrd) {
 368                         if (set_address(&ifr1, 1) < 0)
 369                                 return -1;
 370                 }
 371                 if (newaddr) {
 372                         if (set_address(&ifr0, 0) < 0)
 373                                 return -1;
 374                 }
 375         }
 376         if (mask)
 377                 return do_chflags(dev, flags, mask);
 378         return 0;
 379 }
 380
 381 int do_iplink(int argc, char **argv)
 382 {
 383         if (argc > 0) {
 384                 if (matches(*argv, "set") == 0)
 385                         return do_set(argc-1, argv+1);
 386                 if (matches(*argv, "show") == 0 ||
 387                     matches(*argv, "lst") == 0 ||
 388                     matches(*argv, "list") == 0)
 389                         return ipaddr_list_link(argc-1, argv+1);
 390                 if (matches(*argv, "help") == 0)
 391                         usage();
 392         } else
 393                 return ipaddr_list_link(0, NULL);
 394
 395         fprintf(stderr, "Command \"%s\" is unknown, try \"ip link help\".\n", *argv);
 396         exit(-1);
 397 }