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 static int print_rule(const struct sockaddr_nl *who, const struct nlmsghdr *n,
  46                       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         if (tb[RTA_SRC]) {
  81                 if (r->rtm_src_len != host_len) {
  82                         fprintf(fp, "from %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                         fprintf(fp, "from %s ", format_host(r->rtm_family,
  90                                                        RTA_PAYLOAD(tb[RTA_SRC]),
  91                                                        RTA_DATA(tb[RTA_SRC]),
  92                                                        abuf, sizeof(abuf))
  93                                 );
  94                 }
  95         } else if (r->rtm_src_len) {
  96                 fprintf(fp, "from 0/%d ", r->rtm_src_len);
  97         } else {
  98                 fprintf(fp, "from all ");
  99         }
 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                 SPRINT_BUF(b1);
 121                 fprintf(fp, "tos %s ", rtnl_dsfield_n2a(r->rtm_tos, b1, sizeof(b1)));
 122         }
 123         if (tb[RTA_PROTOINFO]) {
 124                 fprintf(fp, "fwmark %#x ", *(__u32*)RTA_DATA(tb[RTA_PROTOINFO]));
 125         }
 126
 127         if (tb[RTA_IIF]) {
 128                 fprintf(fp, "iif %s ", (char*)RTA_DATA(tb[RTA_IIF]));
 129         }
 130
 131         if (r->rtm_table)
 132                 fprintf(fp, "lookup %s ", rtnl_rttable_n2a(r->rtm_table, b1, sizeof(b1)));
 133
 134         if (tb[RTA_FLOW]) {
 135                 __u32 to = *(__u32*)RTA_DATA(tb[RTA_FLOW]);
 136                 __u32 from = to>>16;
 137                 to &= 0xFFFF;
 138                 if (from) {
 139                         fprintf(fp, "realms %s/",
 140                                 rtnl_rtrealm_n2a(from, b1, sizeof(b1)));
 141                 }
 142                 fprintf(fp, "%s ",
 143                         rtnl_rtrealm_n2a(to, b1, sizeof(b1)));
 144         }
 145
 146         if (r->rtm_type == RTN_NAT) {
 147                 if (tb[RTA_GATEWAY]) {
 148                         fprintf(fp, "map-to %s ",
 149                                 format_host(r->rtm_family,
 150                                             RTA_PAYLOAD(tb[RTA_GATEWAY]),
 151                                             RTA_DATA(tb[RTA_GATEWAY]),
 152                                             abuf, sizeof(abuf)));
 153                 } else
 154                         fprintf(fp, "masquerade");
 155         } else if (r->rtm_type != RTN_UNICAST)
 156                 fprintf(fp, "%s", rtnl_rtntype_n2a(r->rtm_type, b1, sizeof(b1)));
 157
 158         fprintf(fp, "\n");
 159         fflush(fp);
 160         return 0;
 161 }
 162
 163 int iprule_list(int argc, 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 (argc > 0) {
 172                 fprintf(stderr, "\"ip rule show\" need not eny arguments.\n");
 173                 return -1;
 174         }
 175
 176         if (rtnl_open(&rth, 0) < 0)
 177                 return 1;
 178
 179         if (rtnl_wilddump_request(&rth, af, RTM_GETRULE) < 0) {
 180                 perror("Cannot send dump request");
 181                 return 1;
 182         }
 183
 184         if (rtnl_dump_filter(&rth, print_rule, stdout, NULL, NULL) < 0) {
 185                 fprintf(stderr, "Dump terminated\n");
 186                 return 1;
 187         }
 188
 189         return 0;
 190 }
 191
 192
 193 int iprule_modify(int cmd, int argc, char **argv)
 194 {
 195         int table_ok = 0;
 196         struct rtnl_handle rth;
 197         struct {
 198                 struct nlmsghdr         n;
 199                 struct rtmsg            r;
 200                 char                    buf[1024];
 201         } req;
 202
 203         memset(&req, 0, sizeof(req));
 204
 205         req.n.nlmsg_type = cmd;
 206         req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
 207         req.n.nlmsg_flags = NLM_F_REQUEST;
 208         req.r.rtm_family = preferred_family;
 209         req.r.rtm_protocol = RTPROT_BOOT;
 210         req.r.rtm_scope = RT_SCOPE_UNIVERSE;
 211         req.r.rtm_table = 0;
 212         req.r.rtm_type = RTN_UNSPEC;
 213
 214         if (cmd == RTM_NEWRULE) {
 215                 req.n.nlmsg_flags |= NLM_F_CREATE|NLM_F_EXCL;
 216                 req.r.rtm_type = RTN_UNICAST;
 217         }
 218
 219         while (argc > 0) {
 220                 if (strcmp(*argv, "from") == 0) {
 221                         inet_prefix dst;
 222                         NEXT_ARG();
 223                         get_prefix(&dst, *argv, req.r.rtm_family);
 224                         req.r.rtm_src_len = dst.bitlen;
 225                         addattr_l(&req.n, sizeof(req), RTA_SRC, &dst.data, dst.bytelen);
 226                 } else if (strcmp(*argv, "to") == 0) {
 227                         inet_prefix dst;
 228                         NEXT_ARG();
 229                         get_prefix(&dst, *argv, req.r.rtm_family);
 230                         req.r.rtm_dst_len = dst.bitlen;
 231                         addattr_l(&req.n, sizeof(req), RTA_DST, &dst.data, dst.bytelen);
 232                 } else if (matches(*argv, "preference") == 0 ||
 233                            matches(*argv, "order") == 0 ||
 234                            matches(*argv, "priority") == 0) {
 235                         __u32 pref;
 236                         NEXT_ARG();
 237                         if (get_u32(&pref, *argv, 0))
 238                                 invarg("preference value is invalid\n", *argv);
 239                         addattr32(&req.n, sizeof(req), RTA_PRIORITY, pref);
 240                 } else if (strcmp(*argv, "tos") == 0) {
 241                         __u32 tos;
 242                         NEXT_ARG();
 243                         if (rtnl_dsfield_a2n(&tos, *argv))
 244                                 invarg("TOS value is invalid\n", *argv);
 245                         req.r.rtm_tos = tos;
 246                 } else if (strcmp(*argv, "fwmark") == 0) {
 247                         __u32 fwmark;
 248                         NEXT_ARG();
 249                         if (get_u32(&fwmark, *argv, 0))
 250                                 invarg("fwmark value is invalid\n", *argv);
 251                         addattr32(&req.n, sizeof(req), RTA_PROTOINFO, fwmark);
 252                 } else if (matches(*argv, "realms") == 0) {
 253                         __u32 realm;
 254                         NEXT_ARG();
 255                         if (get_rt_realms(&realm, *argv))
 256                                 invarg("invalid realms\n", *argv);
 257                         addattr32(&req.n, sizeof(req), RTA_FLOW, realm);
 258                 } else if (matches(*argv, "table") == 0 ||
 259                            strcmp(*argv, "lookup") == 0) {
 260                         int tid;
 261                         NEXT_ARG();
 262                         if (rtnl_rttable_a2n(&tid, *argv))
 263                                 invarg("invalid table ID\n", *argv);
 264                         req.r.rtm_table = tid;
 265                         table_ok = 1;
 266                 } else if (strcmp(*argv, "dev") == 0 ||
 267                            strcmp(*argv, "iif") == 0) {
 268                         NEXT_ARG();
 269                         addattr_l(&req.n, sizeof(req), RTA_IIF, *argv, strlen(*argv)+1);
 270                 } else if (strcmp(*argv, "nat") == 0 ||
 271                            matches(*argv, "map-to") == 0) {
 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 (strcmp(*argv, "type") == 0) {
 279                                 NEXT_ARG();
 280                         }
 281                         if (matches(*argv, "help") == 0)
 282                                 usage();
 283                         if (rtnl_rtntype_a2n(&type, *argv))
 284                                 invarg("Failed to parse rule type", *argv);
 285                         req.r.rtm_type = type;
 286                 }
 287                 argc--;
 288                 argv++;
 289         }
 290
 291         if (req.r.rtm_family == AF_UNSPEC)
 292                 req.r.rtm_family = AF_INET;
 293
 294         if (!table_ok && cmd == RTM_NEWRULE)
 295                 req.r.rtm_table = RT_TABLE_MAIN;
 296
 297         if (rtnl_open(&rth, 0) < 0)
 298                 return 1;
 299
 300         if (rtnl_talk(&rth, &req.n, 0, 0, NULL, NULL, NULL) < 0)
 301                 return 2;
 302
 303         return 0;
 304 }
 305
 306 int do_iprule(int argc, char **argv)
 307 {
 308         if (argc < 1) {
 309                 return iprule_list(0, NULL);
 310         } else if (matches(argv[0], "list") == 0 ||
 311                    matches(argv[0], "lst") == 0 ||
 312                    matches(argv[0], "show") == 0) {
 313                 return iprule_list(argc-1, argv+1);
 314         } else if (matches(argv[0], "add") == 0) {
 315                 return iprule_modify(RTM_NEWRULE, argc-1, argv+1);
 316         } else if (matches(argv[0], "delete") == 0) {
 317                 return iprule_modify(RTM_DELRULE, argc-1, argv+1);
 318         } else if (matches(argv[0], "help") == 0)
 319                 usage();
 320
 321         fprintf(stderr, "Command \"%s\" is unknown, try \"ip rule help\".\n", *argv);
 322         exit(-1);
 323 }
 324