networking/libiproute/iprule.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * iprule.c             "ip rule".
   4  *
   5  *              This program is free software; you can redistribute it and/or
   6  *              modify it under the terms of the GNU General Public License
   7  *              as published by the Free Software Foundation; either version
   8  *              2 of the License, or (at your option) any later version.
   9  *
  10  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  11  *
  12  *
  13  * Changes:
  14  *
  15  * Rani Assaf <rani@magic.metawire.com> 980929: resolve addresses
  16  * initially integrated into busybox by Bernhard Fischer
  17  */
  18
  19 #include <syslog.h>
  20 #include <netinet/in.h>
  21 #include <netinet/ip.h>
  22 #include <arpa/inet.h>
  23
  24 #include "ip_common.h"  /* #include "libbb.h" is inside */
  25 #include "rt_names.h"
  26 #include "utils.h"
  27
  28 /*
  29 static void usage(void) __attribute__((noreturn));
  30
  31 static void usage(void)
  32 {
  33         fprintf(stderr, "Usage: ip rule [ list | add | del ] SELECTOR ACTION\n");
  34         fprintf(stderr, "SELECTOR := [ from PREFIX ] [ to PREFIX ] [ tos TOS ] [ fwmark FWMARK ]\n");
  35         fprintf(stderr, "            [ dev STRING ] [ pref NUMBER ]\n");
  36         fprintf(stderr, "ACTION := [ table TABLE_ID ] [ nat ADDRESS ]\n");
  37         fprintf(stderr, "          [ prohibit | reject | unreachable ]\n");
  38         fprintf(stderr, "          [ realms [SRCREALM/]DSTREALM ]\n");
  39         fprintf(stderr, "TABLE_ID := [ local | main | default | NUMBER ]\n");
  40         exit(-1);
  41 }
  42 */
  43
  44 static int print_rule(struct sockaddr_nl *who ATTRIBUTE_UNUSED,
  45                                         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         fprintf(fp, "from ");
  80         if (tb[RTA_SRC]) {
  81                 if (r->rtm_src_len != host_len) {
  82                         fprintf(fp, "%s/%u", rt_addr_n2a(r->rtm_family,
  83                                                          RTA_PAYLOAD(tb[RTA_SRC]),
  84                                                          RTA_DATA(tb[RTA_SRC]),
  85                                                          abuf, sizeof(abuf)),
  86                                 r->rtm_src_len
  87                                 );
  88                 } else {
  89                         fputs(format_host(r->rtm_family,
  90                                                        RTA_PAYLOAD(tb[RTA_SRC]),
  91                                                        RTA_DATA(tb[RTA_SRC]),
  92                                                        abuf, sizeof(abuf)), fp);
  93                 }
  94         } else if (r->rtm_src_len) {
  95                 fprintf(fp, "0/%d", r->rtm_src_len);
  96         } else {
  97                 fprintf(fp, "all");
  98         }
  99         fprintf(fp, " ");
 100
 101         if (tb[RTA_DST]) {
 102                 if (r->rtm_dst_len != host_len) {
 103                         fprintf(fp, "to %s/%u ", rt_addr_n2a(r->rtm_family,
 104                                                          RTA_PAYLOAD(tb[RTA_DST]),
 105                                                          RTA_DATA(tb[RTA_DST]),
 106                                                          abuf, sizeof(abuf)),
 107                                 r->rtm_dst_len
 108                                 );
 109                 } else {
 110                         fprintf(fp, "to %s ", format_host(r->rtm_family,
 111                                                        RTA_PAYLOAD(tb[RTA_DST]),
 112                                                        RTA_DATA(tb[RTA_DST]),
 113                                                        abuf, sizeof(abuf)));
 114                 }
 115         } else if (r->rtm_dst_len) {
 116                 fprintf(fp, "to 0/%d ", r->rtm_dst_len);
 117         }
 118
 119         if (r->rtm_tos) {
 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 ", *(uint32_t*)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                 uint32_t to = *(uint32_t*)RTA_DATA(tb[RTA_FLOW]);
 135                 uint32_t 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                 fputs(rtnl_rtntype_n2a(r->rtm_type, b1, sizeof(b1)), fp);
 156
 157         fputc('\n', fp);
 158         fflush(fp);
 159         return 0;
 160 }
 161
 162 /* Return value becomes exitcode. It's okay to not return at all */
 163 static int iprule_list(char **argv)
 164 {
 165         struct rtnl_handle rth;
 166         int af = preferred_family;
 167
 168         if (af == AF_UNSPEC)
 169                 af = AF_INET;
 170
 171         if (*argv) {
 172                 //bb_error_msg("\"rule show\" needs no arguments");
 173                 bb_warn_ignoring_args(1);
 174                 return -1;
 175         }
 176
 177         xrtnl_open(&rth);
 178
 179         xrtnl_wilddump_request(&rth, af, RTM_GETRULE);
 180         xrtnl_dump_filter(&rth, print_rule, stdout);
 181
 182         return 0;
 183 }
 184
 185 /* Return value becomes exitcode. It's okay to not return at all */
 186 static int iprule_modify(int cmd, char **argv)
 187 {
 188         static const char keywords[] ALIGN1 =
 189                 "from\0""to\0""preference\0""order\0""priority\0"
 190                 "tos\0""fwmark\0""realms\0""table\0""lookup\0""dev\0"
 191                 "iif\0""nat\0""map-to\0""type\0""help\0";
 192         enum {
 193                 ARG_from = 1, ARG_to, ARG_preference, ARG_order, ARG_priority,
 194                 ARG_tos, ARG_fwmark, ARG_realms, ARG_table, ARG_lookup, ARG_dev,
 195                 ARG_iif, ARG_nat, ARG_map_to, ARG_type, ARG_help
 196         };
 197         bool table_ok = 0;
 198         struct rtnl_handle rth;
 199         struct {
 200                 struct nlmsghdr n;
 201                 struct rtmsg    r;
 202                 char            buf[1024];
 203         } req;
 204         smalluint key;
 205
 206         memset(&req, 0, sizeof(req));
 207
 208         req.n.nlmsg_type = cmd;
 209         req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
 210         req.n.nlmsg_flags = NLM_F_REQUEST;
 211         req.r.rtm_family = preferred_family;
 212         req.r.rtm_protocol = RTPROT_BOOT;
 213         req.r.rtm_scope = RT_SCOPE_UNIVERSE;
 214         req.r.rtm_table = 0;
 215         req.r.rtm_type = RTN_UNSPEC;
 216
 217         if (cmd == RTM_NEWRULE) {
 218                 req.n.nlmsg_flags |= NLM_F_CREATE|NLM_F_EXCL;
 219                 req.r.rtm_type = RTN_UNICAST;
 220         }
 221
 222         while (*argv) {
 223                 key = index_in_substrings(keywords, *argv) + 1;
 224                 if (key == 0) /* no match found in keywords array, bail out. */
 225                         bb_error_msg_and_die(bb_msg_invalid_arg, *argv, applet_name);
 226                 if (key == ARG_from) {
 227                         inet_prefix dst;
 228                         NEXT_ARG();
 229                         get_prefix(&dst, *argv, req.r.rtm_family);
 230                         req.r.rtm_src_len = dst.bitlen;
 231                         addattr_l(&req.n, sizeof(req), RTA_SRC, &dst.data, dst.bytelen);
 232                 } else if (key == ARG_to) {
 233                         inet_prefix dst;
 234                         NEXT_ARG();
 235                         get_prefix(&dst, *argv, req.r.rtm_family);
 236                         req.r.rtm_dst_len = dst.bitlen;
 237                         addattr_l(&req.n, sizeof(req), RTA_DST, &dst.data, dst.bytelen);
 238                 } else if (key == ARG_preference ||
 239                            key == ARG_order ||
 240                            key == ARG_priority) {
 241                         uint32_t pref;
 242                         NEXT_ARG();
 243                         if (get_u32(&pref, *argv, 0))
 244                                 invarg(*argv, "preference");
 245                         addattr32(&req.n, sizeof(req), RTA_PRIORITY, pref);
 246                 } else if (key == ARG_tos) {
 247                         uint32_t tos;
 248                         NEXT_ARG();
 249                         if (rtnl_dsfield_a2n(&tos, *argv))
 250                                 invarg(*argv, "TOS");
 251                         req.r.rtm_tos = tos;
 252                 } else if (key == ARG_fwmark) {
 253                         uint32_t fwmark;
 254                         NEXT_ARG();
 255                         if (get_u32(&fwmark, *argv, 0))
 256                                 invarg(*argv, "fwmark");
 257                         addattr32(&req.n, sizeof(req), RTA_PROTOINFO, fwmark);
 258                 } else if (key == ARG_realms) {
 259                         uint32_t realm;
 260                         NEXT_ARG();
 261                         if (get_rt_realms(&realm, *argv))
 262                                 invarg(*argv, "realms");
 263                         addattr32(&req.n, sizeof(req), RTA_FLOW, realm);
 264                 } else if (key == ARG_table ||
 265                            key == ARG_lookup) {
 266                         uint32_t tid;
 267                         NEXT_ARG();
 268                         if (rtnl_rttable_a2n(&tid, *argv))
 269                                 invarg(*argv, "table ID");
 270                         req.r.rtm_table = tid;
 271                         table_ok = 1;
 272                 } else if (key == ARG_dev ||
 273                            key == ARG_iif) {
 274                         NEXT_ARG();
 275                         addattr_l(&req.n, sizeof(req), RTA_IIF, *argv, strlen(*argv)+1);
 276                 } else if (key == ARG_nat ||
 277                            key == ARG_map_to) {
 278                         NEXT_ARG();
 279                         addattr32(&req.n, sizeof(req), RTA_GATEWAY, get_addr32(*argv));
 280                         req.r.rtm_type = RTN_NAT;
 281                 } else {
 282                         int type;
 283
 284                         if (key == ARG_type) {
 285                                 NEXT_ARG();
 286                         }
 287                         if (key == ARG_help)
 288                                 bb_show_usage();
 289                         if (rtnl_rtntype_a2n(&type, *argv))
 290                                 invarg(*argv, "type");
 291                         req.r.rtm_type = type;
 292                 }
 293                 argv++;
 294         }
 295
 296         if (req.r.rtm_family == AF_UNSPEC)
 297                 req.r.rtm_family = AF_INET;
 298
 299         if (!table_ok && cmd == RTM_NEWRULE)
 300                 req.r.rtm_table = RT_TABLE_MAIN;
 301
 302         xrtnl_open(&rth);
 303
 304         if (rtnl_talk(&rth, &req.n, 0, 0, NULL, NULL, NULL) < 0)
 305                 return 2;
 306
 307         return 0;
 308 }
 309
 310 /* Return value becomes exitcode. It's okay to not return at all */
 311 int do_iprule(char **argv)
 312 {
 313         static const char ip_rule_commands[] ALIGN1 =
 314                 "add\0""delete\0""list\0""show\0";
 315         int cmd = 2; /* list */
 316
 317         if (!*argv)
 318                 return iprule_list(argv);
 319
 320         cmd = index_in_substrings(ip_rule_commands, *argv);
 321         switch (cmd) {
 322                 case 0: /* add */
 323                         cmd = RTM_NEWRULE;
 324                         break;
 325                 case 1: /* delete */
 326                         cmd = RTM_DELRULE;
 327                         break;
 328                 case 2: /* list */
 329                 case 3: /* show */
 330                         return iprule_list(argv+1);
 331                         break;
 332                 default:
 333                         bb_error_msg_and_die("unknown command %s", *argv);
 334         }
 335         return iprule_modify(cmd, argv+1);
 336 }