ip/iprule.c

   1 /*
   2  * iprule.c             "ip rule".
   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  * Changes:
  13  *
  14  * Rani Assaf <rani@magic.metawire.com> 980929: resolve addresses
  15  */
  16
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <unistd.h>
  20 #include <syslog.h>
  21 #include <fcntl.h>
  22 #include <sys/socket.h>
  23 #include <netinet/in.h>
  24 #include <netinet/ip.h>
  25 #include <arpa/inet.h>
  26 #include <string.h>
  27
  28 #include "rt_names.h"
  29 #include "utils.h"
  30
  31 static void usage(void) __attribute__((noreturn));
  32
  33 static void usage(void)
  34 {
  35         fprintf(stderr, "Usage: ip rule [ list | add | del ] SELECTOR ACTION\n");
  36         fprintf(stderr, "SELECTOR := [ from PREFIX ] [ to PREFIX ] [ tos TOS ] [ fwmark FWMARK ]\n");
  37         fprintf(stderr, "            [ dev STRING ] [ pref NUMBER ]\n");
  38         fprintf(stderr, "ACTION := [ table TABLE_ID ] [ nat ADDRESS ]\n");
  39         fprintf(stderr, "          [ prohibit | reject | unreachable ]\n");
  40         fprintf(stderr, "          [ realms [SRCREALM/]DSTREALM ]\n");
  41         fprintf(stderr, "TABLE_ID := [ local | main | default | NUMBER ]\n");
  42         exit(-1);
  43 }
  44
  45 int print_rule(struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
  46 {
  47         FILE *fp = (FILE*)arg;
  48         struct rtmsg *r = NLMSG_DATA(n);
  49         int len = n->nlmsg_len;
  50         int host_len = -1;
  51         struct rtattr * tb[RTA_MAX+1];
  52         char abuf[256];
  53         SPRINT_BUF(b1);
  54
  55         if (n->nlmsg_type != RTM_NEWRULE)
  56                 return 0;
  57
  58         len -= NLMSG_LENGTH(sizeof(*r));
  59         if (len < 0)
  60                 return -1;
  61
  62         memset(tb, 0, sizeof(tb));
  63         parse_rtattr(tb, RTA_MAX, RTM_RTA(r), len);
  64
  65         if (r->rtm_family == AF_INET)
  66                 host_len = 32;
  67         else if (r->rtm_family == AF_INET6)
  68                 host_len = 128;
  69         else if (r->rtm_family == AF_DECnet)
  70                 host_len = 16;
  71         else if (r->rtm_family == AF_IPX)
  72                 host_len = 80;
  73
  74         if (tb[RTA_PRIORITY])
  75                 fprintf(fp, "%u:\t", *(unsigned*)RTA_DATA(tb[RTA_PRIORITY]));
  76         else
  77                 fprintf(fp, "0:\t");
  78
  79         if (tb[RTA_SRC]) {
  80                 if (r->rtm_src_len != host_len) {
  81                         fprintf(fp, "from %s/%u ", rt_addr_n2a(r->rtm_family,
  82                                                          RTA_PAYLOAD(tb[RTA_SRC]),
  83                                                          RTA_DATA(tb[RTA_SRC]),
  84                                                          abuf, sizeof(abuf)),
  85                                 r->rtm_src_len
  86                                 );
  87                 } else {
  88                         fprintf(fp, "from %s ", format_host(r->rtm_family,
  89                                                        RTA_PAYLOAD(tb[RTA_SRC]),
  90                                                        RTA_DATA(tb[RTA_SRC]),
  91                                                        abuf, sizeof(abuf))
  92                                 );
  93                 }
  94         } else if (r->rtm_src_len) {
  95                 fprintf(fp, "from 0/%d ", r->rtm_src_len);
  96         } else {
  97                 fprintf(fp, "from all ");
  98         }
  99
 100         if (tb[RTA_DST]) {
 101                 if (r->rtm_dst_len != host_len) {
 102                         fprintf(fp, "to %s/%u ", rt_addr_n2a(r->rtm_family,
 103                                                          RTA_PAYLOAD(tb[RTA_DST]),
 104                                                          RTA_DATA(tb[RTA_DST]),
 105                                                          abuf, sizeof(abuf)),
 106                                 r->rtm_dst_len
 107                                 );
 108                 } else {
 109                         fprintf(fp, "to %s ", format_host(r->rtm_family,
 110                                                        RTA_PAYLOAD(tb[RTA_DST]),
 111                                                        RTA_DATA(tb[RTA_DST]),
 112                                                        abuf, sizeof(abuf)));
 113                 }
 114         } else if (r->rtm_dst_len) {
 115                 fprintf(fp, "to 0/%d ", r->rtm_dst_len);
 116         }
 117
 118         if (r->rtm_tos) {
 119                 SPRINT_BUF(b1);
 120                 fprintf(fp, "tos %s ", rtnl_dsfield_n2a(r->rtm_tos, b1, sizeof(b1)));
 121         }
 122         if (tb[RTA_PROTOINFO]) {
 123                 fprintf(fp, "fwmark %#x ", *(__u32*)RTA_DATA(tb[RTA_PROTOINFO]));
 124         }
 125
 126         if (tb[RTA_IIF]) {
 127                 fprintf(fp, "iif %s ", (char*)RTA_DATA(tb[RTA_IIF]));
 128         }
 129
 130         if (r->rtm_table)
 131                 fprintf(fp, "lookup %s ", rtnl_rttable_n2a(r->rtm_table, b1, sizeof(b1)));
 132
 133         if (tb[RTA_FLOW]) {
 134                 __u32 to = *(__u32*)RTA_DATA(tb[RTA_FLOW]);
 135                 __u32 from = to>>16;
 136                 to &= 0xFFFF;
 137                 if (from) {
 138                         fprintf(fp, "realms %s/",
 139                                 rtnl_rtrealm_n2a(from, b1, sizeof(b1)));
 140                 }
 141                 fprintf(fp, "%s ",
 142                         rtnl_rtrealm_n2a(to, b1, sizeof(b1)));
 143         }
 144
 145         if (r->rtm_type == RTN_NAT) {
 146                 if (tb[RTA_GATEWAY]) {
 147                         fprintf(fp, "map-to %s ",
 148                                 format_host(r->rtm_family,
 149                                             RTA_PAYLOAD(tb[RTA_GATEWAY]),
 150                                             RTA_DATA(tb[RTA_GATEWAY]),
 151                                             abuf, sizeof(abuf)));
 152                 } else
 153                         fprintf(fp, "masquerade");
 154         } else if (r->rtm_type != RTN_UNICAST)
 155                 fprintf(fp, "%s", rtnl_rtntype_n2a(r->rtm_type, b1, sizeof(b1)));
 156
 157         fprintf(fp, "\n");
 158         fflush(fp);
 159         return 0;
 160 }
 161
 162 int iprule_list(int argc, char **argv)
 163 {
 164         struct rtnl_handle rth;
 165         int af = preferred_family;
 166
 167         if (af == AF_UNSPEC)
 168                 af = AF_INET;
 169
 170         if (argc > 0) {
 171                 fprintf(stderr, "\"ip rule show\" need not eny arguments.\n");
 172                 return -1;
 173         }
 174
 175         if (rtnl_open(&rth, 0) < 0)
 176                 return 1;
 177
 178         if (rtnl_wilddump_request(&rth, af, RTM_GETRULE) < 0) {
 179                 perror("Cannot send dump request");
 180                 return 1;
 181         }
 182
 183         if (rtnl_dump_filter(&rth, print_rule, stdout, NULL, NULL) < 0) {
 184                 fprintf(stderr, "Dump terminated\n");
 185                 return 1;
 186         }
 187
 188         return 0;
 189 }
 190
 191
 192 int iprule_modify(int cmd, int argc, char **argv)
 193 {
 194         int table_ok = 0;
 195         struct rtnl_handle rth;
 196         struct {
 197                 struct nlmsghdr         n;
 198                 struct rtmsg            r;
 199                 char                    buf[1024];
 200         } req;
 201
 202         memset(&req, 0, sizeof(req));
 203
 204         req.n.nlmsg_type = cmd;
 205         req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
 206         req.n.nlmsg_flags = NLM_F_REQUEST;
 207         req.r.rtm_family = preferred_family;
 208         req.r.rtm_protocol = RTPROT_BOOT;
 209         req.r.rtm_scope = RT_SCOPE_UNIVERSE;
 210         req.r.rtm_table = 0;
 211         req.r.rtm_type = RTN_UNSPEC;
 212
 213         if (cmd == RTM_NEWRULE) {
 214                 req.n.nlmsg_flags |= NLM_F_CREATE|NLM_F_EXCL;
 215                 req.r.rtm_type = RTN_UNICAST;
 216         }
 217
 218         while (argc > 0) {
 219                 if (strcmp(*argv, "from") == 0) {
 220                         inet_prefix dst;
 221                         NEXT_ARG();
 222                         get_prefix(&dst, *argv, req.r.rtm_family);
 223                         req.r.rtm_src_len = dst.bitlen;
 224                         addattr_l(&req.n, sizeof(req), RTA_SRC, &dst.data, dst.bytelen);
 225                 } else if (strcmp(*argv, "to") == 0) {
 226                         inet_prefix dst;
 227                         NEXT_ARG();
 228                         get_prefix(&dst, *argv, req.r.rtm_family);
 229                         req.r.rtm_dst_len = dst.bitlen;
 230                         addattr_l(&req.n, sizeof(req), RTA_DST, &dst.data, dst.bytelen);
 231                 } else if (matches(*argv, "preference") == 0 ||
 232                            matches(*argv, "order") == 0 ||
 233                            matches(*argv, "priority") == 0) {
 234                         __u32 pref;
 235                         NEXT_ARG();
 236                         if (get_u32(&pref, *argv, 0))
 237                                 invarg("preference value is invalid\n", *argv);
 238                         addattr32(&req.n, sizeof(req), RTA_PRIORITY, pref);
 239                 } else if (strcmp(*argv, "tos") == 0) {
 240                         __u32 tos;
 241                         NEXT_ARG();
 242                         if (rtnl_dsfield_a2n(&tos, *argv))
 243                                 invarg("TOS value is invalid\n", *argv);
 244                         req.r.rtm_tos = tos;
 245                 } else if (strcmp(*argv, "fwmark") == 0) {
 246                         __u32 fwmark;
 247                         NEXT_ARG();
 248                         if (get_u32(&fwmark, *argv, 0))
 249                                 invarg("fwmark value is invalid\n", *argv);
 250                         addattr32(&req.n, sizeof(req), RTA_PROTOINFO, fwmark);
 251                 } else if (matches(*argv, "realms") == 0) {
 252                         __u32 realm;
 253                         NEXT_ARG();
 254                         if (get_rt_realms(&realm, *argv))
 255                                 invarg("invalid realms\n", *argv);
 256                         addattr32(&req.n, sizeof(req), RTA_FLOW, realm);
 257                 } else if (matches(*argv, "table") == 0 ||
 258                            strcmp(*argv, "lookup") == 0) {
 259                         int tid;
 260                         NEXT_ARG();
 261                         if (rtnl_rttable_a2n(&tid, *argv))
 262                                 invarg("invalid table ID\n", *argv);
 263                         req.r.rtm_table = tid;
 264                         table_ok = 1;
 265                 } else if (strcmp(*argv, "dev") == 0 ||
 266                            strcmp(*argv, "iif") == 0) {
 267                         NEXT_ARG();
 268                         addattr_l(&req.n, sizeof(req), RTA_IIF, *argv, strlen(*argv)+1);
 269                 } else if (strcmp(*argv, "nat") == 0 ||
 270                            matches(*argv, "map-to") == 0) {
 271                         NEXT_ARG();
 272                         addattr32(&req.n, sizeof(req), RTA_GATEWAY, get_addr32(*argv));
 273                         req.r.rtm_type = RTN_NAT;
 274                 } else {
 275                         int type;
 276
 277                         if (strcmp(*argv, "type") == 0) {
 278                                 NEXT_ARG();
 279                         }
 280                         if (matches(*argv, "help") == 0)
 281                                 usage();
 282                         if (rtnl_rtntype_a2n(&type, *argv))
 283                                 invarg("Failed to parse rule type", *argv);
 284                         req.r.rtm_type = type;
 285                 }
 286                 argc--;
 287                 argv++;
 288         }
 289
 290         if (req.r.rtm_family == AF_UNSPEC)
 291                 req.r.rtm_family = AF_INET;
 292
 293         if (!table_ok && cmd == RTM_NEWRULE)
 294                 req.r.rtm_table = RT_TABLE_MAIN;
 295
 296         if (rtnl_open(&rth, 0) < 0)
 297                 return 1;
 298
 299         if (rtnl_talk(&rth, &req.n, 0, 0, NULL, NULL, NULL) < 0)
 300                 return 2;
 301
 302         return 0;
 303 }
 304
 305 int do_iprule(int argc, char **argv)
 306 {
 307         if (argc < 1) {
 308                 return iprule_list(0, NULL);
 309         } else if (matches(argv[0], "list") == 0 ||
 310                    matches(argv[0], "lst") == 0 ||
 311                    matches(argv[0], "show") == 0) {
 312                 return iprule_list(argc-1, argv+1);
 313         } else if (matches(argv[0], "add") == 0) {
 314                 return iprule_modify(RTM_NEWRULE, argc-1, argv+1);
 315         } else if (matches(argv[0], "delete") == 0) {
 316                 return iprule_modify(RTM_DELRULE, argc-1, argv+1);
 317         } else if (matches(argv[0], "help") == 0)
 318                 usage();
 319
 320         fprintf(stderr, "Command \"%s\" is unknown, try \"ip rule help\".\n", *argv);
 321         exit(-1);
 322 }
 323