tc/m_nat.c

   1 /*
   2  * m_nat.c              NAT module
   3  *
   4  *              This program is free software; you can distribute 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:     Herbert Xu <herbert@gondor.apana.org.au>
  10  *
  11  */
  12
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <unistd.h>
  16 #include <syslog.h>
  17 #include <fcntl.h>
  18 #include <sys/socket.h>
  19 #include <netinet/in.h>
  20 #include <arpa/inet.h>
  21 #include <string.h>
  22 #include "utils.h"
  23 #include "tc_util.h"
  24 #include <linux/tc_act/tc_nat.h>
  25
  26 static void
  27 explain(void)
  28 {
  29         fprintf(stderr, "Usage: ... nat NAT\n"
  30                         "NAT := DIRECTION OLD NEW\n"
  31                         "DIRECTION := { ingress | egress }\n"
  32                         "OLD := PREFIX\n"
  33                         "NEW := ADDRESS\n");
  34 }
  35
  36 static void
  37 usage(void)
  38 {
  39         explain();
  40         exit(-1);
  41 }
  42
  43 static int
  44 parse_nat_args(int *argc_p, char ***argv_p,struct tc_nat *sel)
  45 {
  46         int argc = *argc_p;
  47         char **argv = *argv_p;
  48         inet_prefix addr;
  49
  50         if (argc <= 0)
  51                 return -1;
  52
  53         if (matches(*argv, "egress") == 0)
  54                 sel->flags |= TCA_NAT_FLAG_EGRESS;
  55         else if (matches(*argv, "ingress") != 0)
  56                 goto bad_val;
  57
  58         NEXT_ARG();
  59
  60         if (get_prefix_1(&addr, *argv, AF_INET))
  61                 goto bad_val;
  62
  63         sel->old_addr = addr.data[0];
  64         sel->mask = htonl(~0u << (32 - addr.bitlen));
  65
  66         NEXT_ARG();
  67
  68         if (get_prefix_1(&addr, *argv, AF_INET))
  69                 goto bad_val;
  70
  71         sel->new_addr = addr.data[0];
  72
  73         argc--;
  74         argv++;
  75
  76         *argc_p = argc;
  77         *argv_p = argv;
  78         return 0;
  79
  80 bad_val:
  81         return -1;
  82 }
  83
  84 static int
  85 parse_nat(struct action_util *a, int *argc_p, char ***argv_p, int tca_id, struct nlmsghdr *n)
  86 {
  87         struct tc_nat sel;
  88
  89         int argc = *argc_p;
  90         char **argv = *argv_p;
  91         int ok = 0;
  92         struct rtattr *tail;
  93
  94         memset(&sel, 0, sizeof(sel));
  95
  96         while (argc > 0) {
  97                 if (matches(*argv, "nat") == 0) {
  98                         NEXT_ARG();
  99                         if (parse_nat_args(&argc, &argv, &sel)) {
 100                                 fprintf(stderr, "Illegal nat construct (%s) \n",
 101                                         *argv);
 102                                 explain();
 103                                 return -1;
 104                         }
 105                         ok++;
 106                         continue;
 107                 } else if (matches(*argv, "help") == 0) {
 108                         usage();
 109                 } else {
 110                         break;
 111                 }
 112
 113         }
 114
 115         if (!ok) {
 116                 explain();
 117                 return -1;
 118         }
 119
 120         if (argc) {
 121                 if (matches(*argv, "reclassify") == 0) {
 122                         sel.action = TC_ACT_RECLASSIFY;
 123                         argc--;
 124                         argv++;
 125                 } else if (matches(*argv, "pipe") == 0) {
 126                         sel.action = TC_ACT_PIPE;
 127                         argc--;
 128                         argv++;
 129                 } else if (matches(*argv, "drop") == 0 ||
 130                         matches(*argv, "shot") == 0) {
 131                         sel.action = TC_ACT_SHOT;
 132                         argc--;
 133                         argv++;
 134                 } else if (matches(*argv, "continue") == 0) {
 135                         sel.action = TC_ACT_UNSPEC;
 136                         argc--;
 137                         argv++;
 138                 } else if (matches(*argv, "pass") == 0) {
 139                         sel.action = TC_ACT_OK;
 140                         argc--;
 141                         argv++;
 142                 }
 143         }
 144
 145         if (argc) {
 146                 if (matches(*argv, "index") == 0) {
 147                         NEXT_ARG();
 148                         if (get_u32(&sel.index, *argv, 10)) {
 149                                 fprintf(stderr, "Pedit: Illegal \"index\"\n");
 150                                 return -1;
 151                         }
 152                         argc--;
 153                         argv++;
 154                 }
 155         }
 156
 157         tail = NLMSG_TAIL(n);
 158         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
 159         addattr_l(n, MAX_MSG, TCA_NAT_PARMS, &sel, sizeof(sel));
 160         tail->rta_len = (char *)NLMSG_TAIL(n) - (char *)tail;
 161
 162         *argc_p = argc;
 163         *argv_p = argv;
 164         return 0;
 165 }
 166
 167 static int
 168 print_nat(struct action_util *au,FILE * f, struct rtattr *arg)
 169 {
 170         struct tc_nat *sel;
 171         struct rtattr *tb[TCA_NAT_MAX + 1];
 172         char buf1[256];
 173         char buf2[256];
 174         SPRINT_BUF(buf3);
 175         int len;
 176
 177         if (arg == NULL)
 178                 return -1;
 179
 180         parse_rtattr_nested(tb, TCA_NAT_MAX, arg);
 181
 182         if (tb[TCA_NAT_PARMS] == NULL) {
 183                 fprintf(f, "[NULL nat parameters]");
 184                 return -1;
 185         }
 186         sel = RTA_DATA(tb[TCA_NAT_PARMS]);
 187
 188         len = ffs(sel->mask);
 189         len = len ? 33 - len : 0;
 190
 191         fprintf(f, " nat %s %s/%d %s %s", sel->flags & TCA_NAT_FLAG_EGRESS ?
 192                                           "egress" : "ingress",
 193                 format_host(AF_INET, 4, &sel->old_addr, buf1, sizeof(buf1)),
 194                 len,
 195                 format_host(AF_INET, 4, &sel->new_addr, buf2, sizeof(buf2)),
 196                 action_n2a(sel->action, buf3, sizeof (buf3)));
 197
 198         if (show_stats) {
 199                 if (tb[TCA_NAT_TM]) {
 200                         struct tcf_t *tm = RTA_DATA(tb[TCA_NAT_TM]);
 201                         print_tm(f,tm);
 202                 }
 203         }
 204
 205         return 0;
 206 }
 207
 208 struct action_util nat_action_util = {
 209         .id = "nat",
 210         .parse_aopt = parse_nat,
 211         .print_aopt = print_nat,
 212 };