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 Reutner-Fischer
  17  */
  18
  19 #include <netinet/in.h>
  20 #include <netinet/ip.h>
  21 #include <arpa/inet.h>
  22
  23 #include "ip_common.h"  /* #include "libbb.h" is inside */
  24 #include "rt_names.h"
  25 #include "utils.h"
  26
  27 /*
  28 static void usage(void) __attribute__((noreturn));
  29
  30 static void usage(void)
  31 {
  32         fprintf(stderr, "Usage: ip rule [ list | add | del ] SELECTOR ACTION\n");
  33         fprintf(stderr, "SELECTOR := [ from PREFIX ] [ to PREFIX ] [ tos TOS ] [ fwmark FWMARK ]\n");
  34         fprintf(stderr, "            [ dev STRING ] [ pref NUMBER ]\n");
  35         fprintf(stderr, "ACTION := [ table TABLE_ID ] [ nat ADDRESS ]\n");
  36         fprintf(stderr, "          [ prohibit | reject | unreachable ]\n");
  37         fprintf(stderr, "          [ realms [SRCREALM/]DSTREALM ]\n");
  38         fprintf(stderr, "TABLE_ID := [ local | main | default | NUMBER ]\n");
  39         exit(-1);
  40 }
  41 */
  42
  43 static int FAST_FUNC print_rule(const struct sockaddr_nl *who UNUSED_PARAM,
  44                                         struct nlmsghdr *n, void *arg UNUSED_PARAM)
  45 {
  46         struct rtmsg *r = NLMSG_DATA(n);
  47         int len = n->nlmsg_len;
  48         int host_len = -1;
  49         struct rtattr * tb[RTA_MAX+1];
  50         char abuf[256];
  51         SPRINT_BUF(b1);
  52
  53         if (n->nlmsg_type != RTM_NEWRULE)
  54                 return 0;
  55
  56         len -= NLMSG_LENGTH(sizeof(*r));
  57         if (len < 0)
  58                 return -1;
  59
  60         memset(tb, 0, sizeof(tb));
  61         parse_rtattr(tb, RTA_MAX, RTM_RTA(r), len);
  62
  63         if (r->rtm_family == AF_INET)
  64                 host_len = 32;
  65         else if (r->rtm_family == AF_INET6)
  66                 host_len = 128;
  67 /*      else if (r->rtm_family == AF_DECnet)
  68                 host_len = 16;
  69         else if (r->rtm_family == AF_IPX)
  70                 host_len = 80;
  71 */
  72         if (tb[RTA_PRIORITY])
  73                 printf("%u:\t", *(unsigned*)RTA_DATA(tb[RTA_PRIORITY]));
  74         else
  75                 printf("0:\t");
  76
  77         printf("from ");
  78         if (tb[RTA_SRC]) {
  79                 if (r->rtm_src_len != host_len) {
  80                         printf("%s/%u", rt_addr_n2a(r->rtm_family,
  81                                                          RTA_DATA(tb[RTA_SRC]),
  82                                                          abuf, sizeof(abuf)),
  83                                 r->rtm_src_len
  84                                 );
  85                 } else {
  86                         fputs(format_host(r->rtm_family,
  87                                                        RTA_PAYLOAD(tb[RTA_SRC]),
  88                                                        RTA_DATA(tb[RTA_SRC]),
  89                                                        abuf, sizeof(abuf)), stdout);
  90                 }
  91         } else if (r->rtm_src_len) {
  92                 printf("0/%d", r->rtm_src_len);
  93         } else {
  94                 printf("all");
  95         }
  96         bb_putchar(' ');
  97
  98         if (tb[RTA_DST]) {
  99                 if (r->rtm_dst_len != host_len) {
 100                         printf("to %s/%u ", rt_addr_n2a(r->rtm_family,
 101                                                          RTA_DATA(tb[RTA_DST]),
 102                                                          abuf, sizeof(abuf)),
 103                                 r->rtm_dst_len
 104                                 );
 105                 } else {
 106                         printf("to %s ", format_host(r->rtm_family,
 107                                                        RTA_PAYLOAD(tb[RTA_DST]),
 108                                                        RTA_DATA(tb[RTA_DST]),
 109                                                        abuf, sizeof(abuf)));
 110                 }
 111         } else if (r->rtm_dst_len) {
 112                 printf("to 0/%d ", r->rtm_dst_len);
 113         }
 114
 115         if (r->rtm_tos) {
 116                 printf("tos %s ", rtnl_dsfield_n2a(r->rtm_tos, b1, sizeof(b1)));
 117         }
 118         if (tb[RTA_PROTOINFO]) {
 119                 printf("fwmark %#x ", *(uint32_t*)RTA_DATA(tb[RTA_PROTOINFO]));
 120         }
 121
 122         if (tb[RTA_IIF]) {
 123                 printf("iif %s ", (char*)RTA_DATA(tb[RTA_IIF]));
 124         }
 125
 126         if (r->rtm_table)
 127                 printf("lookup %s ", rtnl_rttable_n2a(r->rtm_table, b1, sizeof(b1)));
 128
 129         if (tb[RTA_FLOW]) {
 130                 uint32_t to = *(uint32_t*)RTA_DATA(tb[RTA_FLOW]);
 131                 uint32_t from = to>>16;
 132                 to &= 0xFFFF;
 133                 if (from) {
 134                         printf("realms %s/",
 135                                 rtnl_rtrealm_n2a(from, b1, sizeof(b1)));
 136                 }
 137                 printf("%s ",
 138                         rtnl_rtrealm_n2a(to, b1, sizeof(b1)));
 139         }
 140
 141         if (r->rtm_type == RTN_NAT) {
 142                 if (tb[RTA_GATEWAY]) {
 143                         printf("map-to %s ",
 144                                 format_host(r->rtm_family,
 145                                             RTA_PAYLOAD(tb[RTA_GATEWAY]),
 146                                             RTA_DATA(tb[RTA_GATEWAY]),
 147                                             abuf, sizeof(abuf)));
 148                 } else
 149                         printf("masquerade");
 150         } else if (r->rtm_type != RTN_UNICAST)
 151                 fputs(rtnl_rtntype_n2a(r->rtm_type, b1, sizeof(b1)), stdout);
 152
 153         bb_putchar('\n');
 154         /*fflush(stdout);*/
 155         return 0;
 156 }
 157
 158 /* Return value becomes exitcode. It's okay to not return at all */
 159 static int iprule_list(char **argv)
 160 {
 161         struct rtnl_handle rth;
 162         int af = preferred_family;
 163
 164         if (af == AF_UNSPEC)
 165                 af = AF_INET;
 166
 167         if (*argv) {
 168                 //bb_error_msg("\"rule show\" needs no arguments");
 169                 bb_warn_ignoring_args(1);
 170                 return -1;
 171         }
 172
 173         xrtnl_open(&rth);
 174
 175         xrtnl_wilddump_request(&rth, af, RTM_GETRULE);
 176         xrtnl_dump_filter(&rth, print_rule, NULL);
 177
 178         return 0;
 179 }
 180
 181 /* Return value becomes exitcode. It's okay to not return at all */
 182 static int iprule_modify(int cmd, char **argv)
 183 {
 184         static const char keywords[] ALIGN1 =
 185                 "from\0""to\0""preference\0""order\0""priority\0"
 186                 "tos\0""fwmark\0""realms\0""table\0""lookup\0""dev\0"
 187                 "iif\0""nat\0""map-to\0""type\0""help\0";
 188         enum {
 189                 ARG_from = 1, ARG_to, ARG_preference, ARG_order, ARG_priority,
 190                 ARG_tos, ARG_fwmark, ARG_realms, ARG_table, ARG_lookup, ARG_dev,
 191                 ARG_iif, ARG_nat, ARG_map_to, ARG_type, ARG_help
 192         };
 193         bool table_ok = 0;
 194         struct rtnl_handle rth;
 195         struct {
 196                 struct nlmsghdr n;
 197                 struct rtmsg    r;
 198                 char            buf[1024];
 199         } req;
 200         smalluint key;
 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 (*argv) {
 219                 key = index_in_substrings(keywords, *argv) + 1;
 220                 if (key == 0) /* no match found in keywords array, bail out. */
 221                         bb_error_msg_and_die(bb_msg_invalid_arg, *argv, applet_name);
 222                 if (key == ARG_from) {
 223                         inet_prefix dst;
 224                         NEXT_ARG();
 225                         get_prefix(&dst, *argv, req.r.rtm_family);
 226                         req.r.rtm_src_len = dst.bitlen;
 227                         addattr_l(&req.n, sizeof(req), RTA_SRC, &dst.data, dst.bytelen);
 228                 } else if (key == ARG_to) {
 229                         inet_prefix dst;
 230                         NEXT_ARG();
 231                         get_prefix(&dst, *argv, req.r.rtm_family);
 232                         req.r.rtm_dst_len = dst.bitlen;
 233                         addattr_l(&req.n, sizeof(req), RTA_DST, &dst.data, dst.bytelen);
 234                 } else if (key == ARG_preference ||
 235                            key == ARG_order ||
 236                            key == ARG_priority) {
 237                         uint32_t pref;
 238                         NEXT_ARG();
 239                         pref = get_u32(*argv, "preference");
 240                         addattr32(&req.n, sizeof(req), RTA_PRIORITY, pref);
 241                 } else if (key == ARG_tos) {
 242                         uint32_t tos;
 243                         NEXT_ARG();
 244                         if (rtnl_dsfield_a2n(&tos, *argv))
 245                                 invarg(*argv, "TOS");
 246                         req.r.rtm_tos = tos;
 247                 } else if (key == ARG_fwmark) {
 248                         uint32_t fwmark;
 249                         NEXT_ARG();
 250                         fwmark = get_u32(*argv, "fwmark");
 251                         addattr32(&req.n, sizeof(req), RTA_PROTOINFO, fwmark);
 252                 } else if (key == ARG_realms) {
 253                         uint32_t realm;
 254                         NEXT_ARG();
 255                         if (get_rt_realms(&realm, *argv))
 256                                 invarg(*argv, "realms");
 257                         addattr32(&req.n, sizeof(req), RTA_FLOW, realm);
 258                 } else if (key == ARG_table ||
 259                            key == ARG_lookup) {
 260                         uint32_t tid;
 261                         NEXT_ARG();
 262                         if (rtnl_rttable_a2n(&tid, *argv))
 263                                 invarg(*argv, "table ID");
 264                         req.r.rtm_table = tid;
 265                         table_ok = 1;
 266                 } else if (key == ARG_dev ||
 267                            key == ARG_iif) {
 268                         NEXT_ARG();
 269                         addattr_l(&req.n, sizeof(req), RTA_IIF, *argv, strlen(*argv)+1);
 270                 } else if (key == ARG_nat ||
 271                            key == ARG_map_to) {
 272                         NEXT_ARG();
 273                         addattr32(&req.n, sizeof(req), RTA_GATEWAY, get_addr32(*argv));
 274                         req.r.rtm_type = RTN_NAT;
 275                 } else {
 276                         int type;
 277
 278                         if (key == ARG_type) {
 279                                 NEXT_ARG();
 280                         }
 281                         if (key == ARG_help)
 282                                 bb_show_usage();
 283                         if (rtnl_rtntype_a2n(&type, *argv))
 284                                 invarg(*argv, "type");
 285                         req.r.rtm_type = type;
 286                 }
 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         xrtnl_open(&rth);
 297
 298         if (rtnl_talk(&rth, &req.n, 0, 0, NULL, NULL, NULL) < 0)
 299                 return 2;
 300
 301         return 0;
 302 }
 303
 304 /* Return value becomes exitcode. It's okay to not return at all */
 305 int do_iprule(char **argv)
 306 {
 307         static const char ip_rule_commands[] ALIGN1 =
 308                 "add\0""delete\0""list\0""show\0";
 309         int cmd = 2; /* list */
 310
 311         if (!*argv)
 312                 return iprule_list(argv);
 313
 314         cmd = index_in_substrings(ip_rule_commands, *argv);
 315         switch (cmd) {
 316                 case 0: /* add */
 317                         cmd = RTM_NEWRULE;
 318                         break;
 319                 case 1: /* delete */
 320                         cmd = RTM_DELRULE;
 321                         break;
 322                 case 2: /* list */
 323                 case 3: /* show */
 324                         return iprule_list(argv+1);
 325                         break;
 326                 default:
 327                         bb_error_msg_and_die("unknown command %s", *argv);
 328         }
 329         return iprule_modify(cmd, argv+1);
 330 }