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  */
  17
  18 #include "libbb.h"
  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 "rt_names.h"
  26 #include "utils.h"
  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 static int print_rule(struct sockaddr_nl *who ATTRIBUTE_UNUSED,
  43                                         struct nlmsghdr *n, void *arg)
  44 {
  45         FILE *fp = (FILE*)arg;
  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                 fprintf(fp, "%u:\t", *(unsigned*)RTA_DATA(tb[RTA_PRIORITY]));
  74         else
  75                 fprintf(fp, "0:\t");
  76
  77         fprintf(fp, "from ");
  78         if (tb[RTA_SRC]) {
  79                 if (r->rtm_src_len != host_len) {
  80                         fprintf(fp, "%s/%u", rt_addr_n2a(r->rtm_family,
  81                                                          RTA_PAYLOAD(tb[RTA_SRC]),
  82                                                          RTA_DATA(tb[RTA_SRC]),
  83                                                          abuf, sizeof(abuf)),
  84                                 r->rtm_src_len
  85                                 );
  86                 } else {
  87                         fprintf(fp, "%s", format_host(r->rtm_family,
  88                                                        RTA_PAYLOAD(tb[RTA_SRC]),
  89                                                        RTA_DATA(tb[RTA_SRC]),
  90                                                        abuf, sizeof(abuf))
  91                                 );
  92                 }
  93         } else if (r->rtm_src_len) {
  94                 fprintf(fp, "0/%d", r->rtm_src_len);
  95         } else {
  96                 fprintf(fp, "all");
  97         }
  98         fprintf(fp, " ");
  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                 fprintf(fp, "tos %s ", rtnl_dsfield_n2a(r->rtm_tos, b1, sizeof(b1)));
 120         }
 121         if (tb[RTA_PROTOINFO]) {
 122                 fprintf(fp, "fwmark %#x ", *(__u32*)RTA_DATA(tb[RTA_PROTOINFO]));
 123         }
 124
 125         if (tb[RTA_IIF]) {
 126                 fprintf(fp, "iif %s ", (char*)RTA_DATA(tb[RTA_IIF]));
 127         }
 128
 129         if (r->rtm_table)
 130                 fprintf(fp, "lookup %s ", rtnl_rttable_n2a(r->rtm_table, b1, sizeof(b1)));
 131
 132         if (tb[RTA_FLOW]) {
 133                 __u32 to = *(__u32*)RTA_DATA(tb[RTA_FLOW]);
 134                 __u32 from = to>>16;
 135                 to &= 0xFFFF;
 136                 if (from) {
 137                         fprintf(fp, "realms %s/",
 138                                 rtnl_rtrealm_n2a(from, b1, sizeof(b1)));
 139                 }
 140                 fprintf(fp, "%s ",
 141                         rtnl_rtrealm_n2a(to, b1, sizeof(b1)));
 142         }
 143
 144         if (r->rtm_type == RTN_NAT) {
 145                 if (tb[RTA_GATEWAY]) {
 146                         fprintf(fp, "map-to %s ",
 147                                 format_host(r->rtm_family,
 148                                             RTA_PAYLOAD(tb[RTA_GATEWAY]),
 149                                             RTA_DATA(tb[RTA_GATEWAY]),
 150                                             abuf, sizeof(abuf)));
 151                 } else
 152                         fprintf(fp, "masquerade");
 153         } else if (r->rtm_type != RTN_UNICAST)
 154                 fprintf(fp, "%s", rtnl_rtntype_n2a(r->rtm_type, b1, sizeof(b1)));
 155
 156         fprintf(fp, "\n");
 157         fflush(fp);
 158         return 0;
 159 }
 160
 161 int iprule_list(int argc, char **argv)
 162 {
 163         struct rtnl_handle rth;
 164         int af = preferred_family;
 165
 166         if (af == AF_UNSPEC)
 167                 af = AF_INET;
 168
 169         if (argc > 0) {
 170                 bb_error_msg("\"rule show\" needs no arguments");
 171                 return -1;
 172         }
 173
 174         if (rtnl_open(&rth, 0) < 0)
 175                 return 1;
 176
 177         if (rtnl_wilddump_request(&rth, af, RTM_GETRULE) < 0) {
 178                 bb_perror_msg("Cannot send dump request");
 179                 return 1;
 180         }
 181
 182         if (rtnl_dump_filter(&rth, print_rule, stdout, NULL, NULL) < 0) {
 183                 bb_error_msg("Dump terminated");
 184                 return 1;
 185         }
 186
 187         return 0;
 188 }
 189
 190
 191 int iprule_modify(int cmd, int argc, char **argv)
 192 {
 193         int 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
 201         memset(&req, 0, sizeof(req));
 202
 203         req.n.nlmsg_type = cmd;
 204         req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
 205         req.n.nlmsg_flags = NLM_F_REQUEST;
 206         req.r.rtm_family = preferred_family;
 207         req.r.rtm_protocol = RTPROT_BOOT;
 208         req.r.rtm_scope = RT_SCOPE_UNIVERSE;
 209         req.r.rtm_table = 0;
 210         req.r.rtm_type = RTN_UNSPEC;
 211
 212         if (cmd == RTM_NEWRULE) {
 213                 req.n.nlmsg_flags |= NLM_F_CREATE|NLM_F_EXCL;
 214                 req.r.rtm_type = RTN_UNICAST;
 215         }
 216
 217         while (argc > 0) {
 218                 if (strcmp(*argv, "from") == 0) {
 219                         inet_prefix dst;
 220                         NEXT_ARG();
 221                         get_prefix(&dst, *argv, req.r.rtm_family);
 222                         req.r.rtm_src_len = dst.bitlen;
 223                         addattr_l(&req.n, sizeof(req), RTA_SRC, &dst.data, dst.bytelen);
 224                 } else if (strcmp(*argv, "to") == 0) {
 225                         inet_prefix dst;
 226                         NEXT_ARG();
 227                         get_prefix(&dst, *argv, req.r.rtm_family);
 228                         req.r.rtm_dst_len = dst.bitlen;
 229                         addattr_l(&req.n, sizeof(req), RTA_DST, &dst.data, dst.bytelen);
 230                 } else if (matches(*argv, "preference") == 0 ||
 231                            matches(*argv, "order") == 0 ||
 232                            matches(*argv, "priority") == 0) {
 233                         __u32 pref;
 234                         NEXT_ARG();
 235                         if (get_u32(&pref, *argv, 0))
 236                                 invarg("preference value", *argv);
 237                         addattr32(&req.n, sizeof(req), RTA_PRIORITY, pref);
 238                 } else if (strcmp(*argv, "tos") == 0) {
 239                         __u32 tos;
 240                         NEXT_ARG();
 241                         if (rtnl_dsfield_a2n(&tos, *argv))
 242                                 invarg("TOS value", *argv);
 243                         req.r.rtm_tos = tos;
 244                 } else if (strcmp(*argv, "fwmark") == 0) {
 245                         __u32 fwmark;
 246                         NEXT_ARG();
 247                         if (get_u32(&fwmark, *argv, 0))
 248                                 invarg("fwmark value", *argv);
 249                         addattr32(&req.n, sizeof(req), RTA_PROTOINFO, fwmark);
 250                 } else if (matches(*argv, "realms") == 0) {
 251                         __u32 realm;
 252                         NEXT_ARG();
 253                         if (get_rt_realms(&realm, *argv))
 254                                 invarg("realms", *argv);
 255                         addattr32(&req.n, sizeof(req), RTA_FLOW, realm);
 256                 } else if (matches(*argv, "table") == 0 ||
 257                            strcmp(*argv, "lookup") == 0) {
 258                         int tid;
 259                         NEXT_ARG();
 260                         if (rtnl_rttable_a2n(&tid, *argv))
 261                                 invarg("table ID", *argv);
 262                         req.r.rtm_table = tid;
 263                         table_ok = 1;
 264                 } else if (strcmp(*argv, "dev") == 0 ||
 265                            strcmp(*argv, "iif") == 0) {
 266                         NEXT_ARG();
 267                         addattr_l(&req.n, sizeof(req), RTA_IIF, *argv, strlen(*argv)+1);
 268                 } else if (strcmp(*argv, "nat") == 0 ||
 269                            matches(*argv, "map-to") == 0) {
 270                         NEXT_ARG();
 271                         addattr32(&req.n, sizeof(req), RTA_GATEWAY, get_addr32(*argv));
 272                         req.r.rtm_type = RTN_NAT;
 273                 } else {
 274                         int type;
 275
 276                         if (strcmp(*argv, "type") == 0) {
 277                                 NEXT_ARG();
 278                         }
 279                         if (matches(*argv, "help") == 0)
 280                                 bb_show_usage();
 281                         if (rtnl_rtntype_a2n(&type, *argv))
 282                                 invarg("Failed to parse rule type", *argv);
 283                         req.r.rtm_type = type;
 284                 }
 285                 argc--;
 286                 argv++;
 287         }
 288
 289         if (req.r.rtm_family == AF_UNSPEC)
 290                 req.r.rtm_family = AF_INET;
 291
 292         if (!table_ok && cmd == RTM_NEWRULE)
 293                 req.r.rtm_table = RT_TABLE_MAIN;
 294
 295         if (rtnl_open(&rth, 0) < 0)
 296                 return 1;
 297
 298         if (rtnl_talk(&rth, &req.n, 0, 0, NULL, NULL, NULL) < 0)
 299                 return 2;
 300
 301         return 0;
 302 }
 303
 304 int do_iprule(int argc, char **argv)
 305 {
 306         static const char * const ip_rule_commands[] =
 307                 {"add", "delete", "list", "show", 0};
 308         int command_num = 2;
 309         int cmd;
 310
 311         if (argc < 1)
 312                 return iprule_list(0, NULL);
 313         if (*argv)
 314                 command_num = index_in_substr_array(ip_rule_commands, *argv);
 315         switch (command_num) {
 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(argc-1, argv+1);
 325                         break;
 326                 default:
 327                         bb_error_msg_and_die("unknown command %s", *argv);
 328         }
 329         return iprule_modify(cmd, argc-1, argv+1);
 330 }
 331