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 <sys/socket.h>
  21 #include <netinet/in.h>
  22 #include <netinet/ip.h>
  23 #include <arpa/inet.h>
  24
  25 #include "ip_common.h"  /* #include "libbb.h" is inside */
  26 #include "rt_names.h"
  27 #include "utils.h"
  28
  29 /*
  30 static void usage(void) __attribute__((noreturn));
  31
  32 static void usage(void)
  33 {
  34         fprintf(stderr, "Usage: ip rule [ list | add | del ] SELECTOR ACTION\n");
  35         fprintf(stderr, "SELECTOR := [ from PREFIX ] [ to PREFIX ] [ tos TOS ] [ fwmark FWMARK ]\n");
  36         fprintf(stderr, "            [ dev STRING ] [ pref NUMBER ]\n");
  37         fprintf(stderr, "ACTION := [ table TABLE_ID ] [ nat ADDRESS ]\n");
  38         fprintf(stderr, "          [ prohibit | reject | unreachable ]\n");
  39         fprintf(stderr, "          [ realms [SRCREALM/]DSTREALM ]\n");
  40         fprintf(stderr, "TABLE_ID := [ local | main | default | NUMBER ]\n");
  41         exit(-1);
  42 }
  43 */
  44
  45 static int print_rule(struct sockaddr_nl *who ATTRIBUTE_UNUSED,
  46                                         struct nlmsghdr *n, void *arg)
  47 {
  48         FILE *fp = (FILE*)arg;
  49         struct rtmsg *r = NLMSG_DATA(n);
  50         int len = n->nlmsg_len;
  51         int host_len = -1;
  52         struct rtattr * tb[RTA_MAX+1];
  53         char abuf[256];
  54         SPRINT_BUF(b1);
  55
  56         if (n->nlmsg_type != RTM_NEWRULE)
  57                 return 0;
  58
  59         len -= NLMSG_LENGTH(sizeof(*r));
  60         if (len < 0)
  61                 return -1;
  62
  63         memset(tb, 0, sizeof(tb));
  64         parse_rtattr(tb, RTA_MAX, RTM_RTA(r), len);
  65
  66         if (r->rtm_family == AF_INET)
  67                 host_len = 32;
  68         else if (r->rtm_family == AF_INET6)
  69                 host_len = 128;
  70 /*      else if (r->rtm_family == AF_DECnet)
  71                 host_len = 16;
  72         else if (r->rtm_family == AF_IPX)
  73                 host_len = 80;
  74 */
  75         if (tb[RTA_PRIORITY])
  76                 fprintf(fp, "%u:\t", *(unsigned*)RTA_DATA(tb[RTA_PRIORITY]));
  77         else
  78                 fprintf(fp, "0:\t");
  79
  80         fprintf(fp, "from ");
  81         if (tb[RTA_SRC]) {
  82                 if (r->rtm_src_len != host_len) {
  83                         fprintf(fp, "%s/%u", rt_addr_n2a(r->rtm_family,
  84                                                          RTA_PAYLOAD(tb[RTA_SRC]),
  85                                                          RTA_DATA(tb[RTA_SRC]),
  86                                                          abuf, sizeof(abuf)),
  87                                 r->rtm_src_len
  88                                 );
  89                 } else {
  90                         fprintf(fp, "%s", format_host(r->rtm_family,
  91                                                        RTA_PAYLOAD(tb[RTA_SRC]),
  92                                                        RTA_DATA(tb[RTA_SRC]),
  93                                                        abuf, sizeof(abuf))
  94                                 );
  95                 }
  96         } else if (r->rtm_src_len) {
  97                 fprintf(fp, "0/%d", r->rtm_src_len);
  98         } else {
  99                 fprintf(fp, "all");
 100         }
 101         fprintf(fp, " ");
 102
 103         if (tb[RTA_DST]) {
 104                 if (r->rtm_dst_len != host_len) {
 105                         fprintf(fp, "to %s/%u ", rt_addr_n2a(r->rtm_family,
 106                                                          RTA_PAYLOAD(tb[RTA_DST]),
 107                                                          RTA_DATA(tb[RTA_DST]),
 108                                                          abuf, sizeof(abuf)),
 109                                 r->rtm_dst_len
 110                                 );
 111                 } else {
 112                         fprintf(fp, "to %s ", format_host(r->rtm_family,
 113                                                        RTA_PAYLOAD(tb[RTA_DST]),
 114                                                        RTA_DATA(tb[RTA_DST]),
 115                                                        abuf, sizeof(abuf)));
 116                 }
 117         } else if (r->rtm_dst_len) {
 118                 fprintf(fp, "to 0/%d ", r->rtm_dst_len);
 119         }
 120
 121         if (r->rtm_tos) {
 122                 fprintf(fp, "tos %s ", rtnl_dsfield_n2a(r->rtm_tos, b1, sizeof(b1)));
 123         }
 124         if (tb[RTA_PROTOINFO]) {
 125                 fprintf(fp, "fwmark %#x ", *(uint32_t*)RTA_DATA(tb[RTA_PROTOINFO]));
 126         }
 127
 128         if (tb[RTA_IIF]) {
 129                 fprintf(fp, "iif %s ", (char*)RTA_DATA(tb[RTA_IIF]));
 130         }
 131
 132         if (r->rtm_table)
 133                 fprintf(fp, "lookup %s ", rtnl_rttable_n2a(r->rtm_table, b1, sizeof(b1)));
 134
 135         if (tb[RTA_FLOW]) {
 136                 uint32_t to = *(uint32_t*)RTA_DATA(tb[RTA_FLOW]);
 137                 uint32_t from = to>>16;
 138                 to &= 0xFFFF;
 139                 if (from) {
 140                         fprintf(fp, "realms %s/",
 141                                 rtnl_rtrealm_n2a(from, b1, sizeof(b1)));
 142                 }
 143                 fprintf(fp, "%s ",
 144                         rtnl_rtrealm_n2a(to, b1, sizeof(b1)));
 145         }
 146
 147         if (r->rtm_type == RTN_NAT) {
 148                 if (tb[RTA_GATEWAY]) {
 149                         fprintf(fp, "map-to %s ",
 150                                 format_host(r->rtm_family,
 151                                             RTA_PAYLOAD(tb[RTA_GATEWAY]),
 152                                             RTA_DATA(tb[RTA_GATEWAY]),
 153                                             abuf, sizeof(abuf)));
 154                 } else
 155                         fprintf(fp, "masquerade");
 156         } else if (r->rtm_type != RTN_UNICAST)
 157                 fprintf(fp, "%s", rtnl_rtntype_n2a(r->rtm_type, b1, sizeof(b1)));
 158
 159         fputc('\n', fp);
 160         fflush(fp);
 161         return 0;
 162 }
 163
 164 /* Return value becomes exitcode. It's okay to not return at all */
 165 static int iprule_list(int argc, char **argv)
 166 {
 167         struct rtnl_handle rth;
 168         int af = preferred_family;
 169
 170         if (af == AF_UNSPEC)
 171                 af = AF_INET;
 172
 173         if (argc > 0) {
 174                 //bb_error_msg("\"rule show\" needs no arguments");
 175                 bb_warn_ignoring_args(argc);
 176                 return -1;
 177         }
 178
 179         xrtnl_open(&rth);
 180
 181         xrtnl_wilddump_request(&rth, af, RTM_GETRULE);
 182         xrtnl_dump_filter(&rth, print_rule, stdout);
 183
 184         return 0;
 185 }
 186
 187
 188 /* Return value becomes exitcode. It's okay to not return at all */
 189 static int iprule_modify(int cmd, int argc, char **argv)
 190 {
 191         int table_ok = 0;
 192         struct rtnl_handle rth;
 193         struct {
 194                 struct nlmsghdr n;
 195                 struct rtmsg    r;
 196                 char            buf[1024];
 197         } req;
 198
 199         memset(&req, 0, sizeof(req));
 200
 201         req.n.nlmsg_type = cmd;
 202         req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
 203         req.n.nlmsg_flags = NLM_F_REQUEST;
 204         req.r.rtm_family = preferred_family;
 205         req.r.rtm_protocol = RTPROT_BOOT;
 206         req.r.rtm_scope = RT_SCOPE_UNIVERSE;
 207         req.r.rtm_table = 0;
 208         req.r.rtm_type = RTN_UNSPEC;
 209
 210         if (cmd == RTM_NEWRULE) {
 211                 req.n.nlmsg_flags |= NLM_F_CREATE|NLM_F_EXCL;
 212                 req.r.rtm_type = RTN_UNICAST;
 213         }
 214
 215         while (argc > 0) {
 216                 if (strcmp(*argv, "from") == 0) {
 217                         inet_prefix dst;
 218                         NEXT_ARG();
 219                         get_prefix(&dst, *argv, req.r.rtm_family);
 220                         req.r.rtm_src_len = dst.bitlen;
 221                         addattr_l(&req.n, sizeof(req), RTA_SRC, &dst.data, dst.bytelen);
 222                 } else if (strcmp(*argv, "to") == 0) {
 223                         inet_prefix dst;
 224                         NEXT_ARG();
 225                         get_prefix(&dst, *argv, req.r.rtm_family);
 226                         req.r.rtm_dst_len = dst.bitlen;
 227                         addattr_l(&req.n, sizeof(req), RTA_DST, &dst.data, dst.bytelen);
 228                 } else if (matches(*argv, "preference") == 0 ||
 229                            matches(*argv, "order") == 0 ||
 230                            matches(*argv, "priority") == 0) {
 231                         uint32_t pref;
 232                         NEXT_ARG();
 233                         if (get_u32(&pref, *argv, 0))
 234                                 invarg("preference value", *argv);
 235                         addattr32(&req.n, sizeof(req), RTA_PRIORITY, pref);
 236                 } else if (strcmp(*argv, "tos") == 0) {
 237                         uint32_t tos;
 238                         NEXT_ARG();
 239                         if (rtnl_dsfield_a2n(&tos, *argv))
 240                                 invarg("TOS value", *argv);
 241                         req.r.rtm_tos = tos;
 242                 } else if (strcmp(*argv, "fwmark") == 0) {
 243                         uint32_t fwmark;
 244                         NEXT_ARG();
 245                         if (get_u32(&fwmark, *argv, 0))
 246                                 invarg("fwmark value", *argv);
 247                         addattr32(&req.n, sizeof(req), RTA_PROTOINFO, fwmark);
 248                 } else if (matches(*argv, "realms") == 0) {
 249                         uint32_t realm;
 250                         NEXT_ARG();
 251                         if (get_rt_realms(&realm, *argv))
 252                                 invarg("realms", *argv);
 253                         addattr32(&req.n, sizeof(req), RTA_FLOW, realm);
 254                 } else if (matches(*argv, "table") == 0 ||
 255                            strcmp(*argv, "lookup") == 0) {
 256                         uint32_t tid;
 257                         NEXT_ARG();
 258                         if (rtnl_rttable_a2n(&tid, *argv))
 259                                 invarg("table ID", *argv);
 260                         req.r.rtm_table = tid;
 261                         table_ok = 1;
 262                 } else if (strcmp(*argv, "dev") == 0 ||
 263                            strcmp(*argv, "iif") == 0) {
 264                         NEXT_ARG();
 265                         addattr_l(&req.n, sizeof(req), RTA_IIF, *argv, strlen(*argv)+1);
 266                 } else if (strcmp(*argv, "nat") == 0 ||
 267                            matches(*argv, "map-to") == 0) {
 268                         NEXT_ARG();
 269                         addattr32(&req.n, sizeof(req), RTA_GATEWAY, get_addr32(*argv));
 270                         req.r.rtm_type = RTN_NAT;
 271                 } else {
 272                         int type;
 273
 274                         if (strcmp(*argv, "type") == 0) {
 275                                 NEXT_ARG();
 276                         }
 277                         if (matches(*argv, "help") == 0)
 278                                 bb_show_usage();
 279                         if (rtnl_rtntype_a2n(&type, *argv))
 280 // bogus-looking error message "invalid argument 'cannot parse rule type' to '<*argv>'"
 281                                 invarg("cannot parse rule type", *argv);
 282                         req.r.rtm_type = type;
 283                 }
 284                 argc--;
 285                 argv++;
 286         }
 287
 288         if (req.r.rtm_family == AF_UNSPEC)
 289                 req.r.rtm_family = AF_INET;
 290
 291         if (!table_ok && cmd == RTM_NEWRULE)
 292                 req.r.rtm_table = RT_TABLE_MAIN;
 293
 294         xrtnl_open(&rth);
 295
 296         if (rtnl_talk(&rth, &req.n, 0, 0, NULL, NULL, NULL) < 0)
 297                 return 2;
 298
 299         return 0;
 300 }
 301
 302 /* Return value becomes exitcode. It's okay to not return at all */
 303 int do_iprule(int argc, char **argv)
 304 {
 305         static const char * const ip_rule_commands[] =
 306                 {"add", "delete", "list", "show", 0};
 307         int cmd = 2; /* list */
 308
 309         if (argc < 1)
 310                 return iprule_list(0, NULL);
 311         if (*argv)
 312                 cmd = index_in_substr_array(ip_rule_commands, *argv);
 313
 314         switch (cmd) {
 315                 case 0: /* add */
 316                         cmd = RTM_NEWRULE;
 317                         break;
 318                 case 1: /* delete */
 319                         cmd = RTM_DELRULE;
 320                         break;
 321                 case 2: /* list */
 322                 case 3: /* show */
 323                         return iprule_list(argc-1, argv+1);
 324                         break;
 325                 default:
 326                         bb_error_msg_and_die("unknown command %s", *argv);
 327         }
 328         return iprule_modify(cmd, argc-1, argv+1);
 329 }