net/netfilter/nf_conntrack_proto_udplite.c

   1 /* (C) 1999-2001 Paul `Rusty' Russell
   2  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   3  * (C) 2007 Patrick McHardy <kaber@trash.net>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/types.h>
  11 #include <linux/timer.h>
  12 #include <linux/module.h>
  13 #include <linux/udp.h>
  14 #include <linux/seq_file.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/ipv6.h>
  17 #include <net/ip6_checksum.h>
  18 #include <net/checksum.h>
  19
  20 #include <linux/netfilter.h>
  21 #include <linux/netfilter_ipv4.h>
  22 #include <linux/netfilter_ipv6.h>
  23 #include <net/netfilter/nf_conntrack_l4proto.h>
  24 #include <net/netfilter/nf_conntrack_ecache.h>
  25 #include <net/netfilter/nf_log.h>
  26
  27 enum udplite_conntrack {
  28         UDPLITE_CT_UNREPLIED,
  29         UDPLITE_CT_REPLIED,
  30         UDPLITE_CT_MAX
  31 };
  32
  33 static unsigned int udplite_timeouts[UDPLITE_CT_MAX] = {
  34         [UDPLITE_CT_UNREPLIED]  = 30*HZ,
  35         [UDPLITE_CT_REPLIED]    = 180*HZ,
  36 };
  37
  38 static int udplite_net_id __read_mostly;
  39 struct udplite_net {
  40         struct nf_proto_net pn;
  41         unsigned int timeouts[UDPLITE_CT_MAX];
  42 };
  43
  44 static inline struct udplite_net *udplite_pernet(struct net *net)
  45 {
  46         return net_generic(net, udplite_net_id);
  47 }
  48
  49 static bool udplite_pkt_to_tuple(const struct sk_buff *skb,
  50                                  unsigned int dataoff,
  51                                  struct net *net,
  52                                  struct nf_conntrack_tuple *tuple)
  53 {
  54         const struct udphdr *hp;
  55         struct udphdr _hdr;
  56
  57         hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
  58         if (hp == NULL)
  59                 return false;
  60
  61         tuple->src.u.udp.port = hp->source;
  62         tuple->dst.u.udp.port = hp->dest;
  63         return true;
  64 }
  65
  66 static bool udplite_invert_tuple(struct nf_conntrack_tuple *tuple,
  67                                  const struct nf_conntrack_tuple *orig)
  68 {
  69         tuple->src.u.udp.port = orig->dst.u.udp.port;
  70         tuple->dst.u.udp.port = orig->src.u.udp.port;
  71         return true;
  72 }
  73
  74 /* Print out the per-protocol part of the tuple. */
  75 static void udplite_print_tuple(struct seq_file *s,
  76                                 const struct nf_conntrack_tuple *tuple)
  77 {
  78         seq_printf(s, "sport=%hu dport=%hu ",
  79                    ntohs(tuple->src.u.udp.port),
  80                    ntohs(tuple->dst.u.udp.port));
  81 }
  82
  83 static unsigned int *udplite_get_timeouts(struct net *net)
  84 {
  85         return udplite_pernet(net)->timeouts;
  86 }
  87
  88 /* Returns verdict for packet, and may modify conntracktype */
  89 static int udplite_packet(struct nf_conn *ct,
  90                           const struct sk_buff *skb,
  91                           unsigned int dataoff,
  92                           enum ip_conntrack_info ctinfo,
  93                           u_int8_t pf,
  94                           unsigned int hooknum,
  95                           unsigned int *timeouts)
  96 {
  97         /* If we've seen traffic both ways, this is some kind of UDP
  98            stream.  Extend timeout. */
  99         if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 100                 nf_ct_refresh_acct(ct, ctinfo, skb,
 101                                    timeouts[UDPLITE_CT_REPLIED]);
 102                 /* Also, more likely to be important, and not a probe */
 103                 if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
 104                         nf_conntrack_event_cache(IPCT_ASSURED, ct);
 105         } else {
 106                 nf_ct_refresh_acct(ct, ctinfo, skb,
 107                                    timeouts[UDPLITE_CT_UNREPLIED]);
 108         }
 109         return NF_ACCEPT;
 110 }
 111
 112 /* Called when a new connection for this protocol found. */
 113 static bool udplite_new(struct nf_conn *ct, const struct sk_buff *skb,
 114                         unsigned int dataoff, unsigned int *timeouts)
 115 {
 116         return true;
 117 }
 118
 119 static int udplite_error(struct net *net, struct nf_conn *tmpl,
 120                          struct sk_buff *skb,
 121                          unsigned int dataoff,
 122                          enum ip_conntrack_info *ctinfo,
 123                          u_int8_t pf,
 124                          unsigned int hooknum)
 125 {
 126         unsigned int udplen = skb->len - dataoff;
 127         const struct udphdr *hdr;
 128         struct udphdr _hdr;
 129         unsigned int cscov;
 130
 131         /* Header is too small? */
 132         hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
 133         if (hdr == NULL) {
 134                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 135                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 136                                       "nf_ct_udplite: short packet ");
 137                 return -NF_ACCEPT;
 138         }
 139
 140         cscov = ntohs(hdr->len);
 141         if (cscov == 0)
 142                 cscov = udplen;
 143         else if (cscov < sizeof(*hdr) || cscov > udplen) {
 144                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 145                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 146                                 "nf_ct_udplite: invalid checksum coverage ");
 147                 return -NF_ACCEPT;
 148         }
 149
 150         /* UDPLITE mandates checksums */
 151         if (!hdr->check) {
 152                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 153                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 154                                       "nf_ct_udplite: checksum missing ");
 155                 return -NF_ACCEPT;
 156         }
 157
 158         /* Checksum invalid? Ignore. */
 159         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 160             nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_UDP,
 161                                 pf)) {
 162                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 163                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 164                                       "nf_ct_udplite: bad UDPLite checksum ");
 165                 return -NF_ACCEPT;
 166         }
 167
 168         return NF_ACCEPT;
 169 }
 170
 171 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 172
 173 #include <linux/netfilter/nfnetlink.h>
 174 #include <linux/netfilter/nfnetlink_cttimeout.h>
 175
 176 static int udplite_timeout_nlattr_to_obj(struct nlattr *tb[],
 177                                          struct net *net, void *data)
 178 {
 179         unsigned int *timeouts = data;
 180         struct udplite_net *un = udplite_pernet(net);
 181
 182         /* set default timeouts for UDPlite. */
 183         timeouts[UDPLITE_CT_UNREPLIED] = un->timeouts[UDPLITE_CT_UNREPLIED];
 184         timeouts[UDPLITE_CT_REPLIED] = un->timeouts[UDPLITE_CT_REPLIED];
 185
 186         if (tb[CTA_TIMEOUT_UDPLITE_UNREPLIED]) {
 187                 timeouts[UDPLITE_CT_UNREPLIED] =
 188                   ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDPLITE_UNREPLIED])) * HZ;
 189         }
 190         if (tb[CTA_TIMEOUT_UDPLITE_REPLIED]) {
 191                 timeouts[UDPLITE_CT_REPLIED] =
 192                   ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDPLITE_REPLIED])) * HZ;
 193         }
 194         return 0;
 195 }
 196
 197 static int
 198 udplite_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 199 {
 200         const unsigned int *timeouts = data;
 201
 202         if (nla_put_be32(skb, CTA_TIMEOUT_UDPLITE_UNREPLIED,
 203                          htonl(timeouts[UDPLITE_CT_UNREPLIED] / HZ)) ||
 204             nla_put_be32(skb, CTA_TIMEOUT_UDPLITE_REPLIED,
 205                          htonl(timeouts[UDPLITE_CT_REPLIED] / HZ)))
 206                 goto nla_put_failure;
 207         return 0;
 208
 209 nla_put_failure:
 210         return -ENOSPC;
 211 }
 212
 213 static const struct nla_policy
 214 udplite_timeout_nla_policy[CTA_TIMEOUT_UDPLITE_MAX+1] = {
 215         [CTA_TIMEOUT_UDPLITE_UNREPLIED] = { .type = NLA_U32 },
 216         [CTA_TIMEOUT_UDPLITE_REPLIED]   = { .type = NLA_U32 },
 217 };
 218 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 219
 220 #ifdef CONFIG_SYSCTL
 221 static struct ctl_table udplite_sysctl_table[] = {
 222         {
 223                 .procname       = "nf_conntrack_udplite_timeout",
 224                 .maxlen         = sizeof(unsigned int),
 225                 .mode           = 0644,
 226                 .proc_handler   = proc_dointvec_jiffies,
 227         },
 228         {
 229                 .procname       = "nf_conntrack_udplite_timeout_stream",
 230                 .maxlen         = sizeof(unsigned int),
 231                 .mode           = 0644,
 232                 .proc_handler   = proc_dointvec_jiffies,
 233         },
 234         { }
 235 };
 236 #endif /* CONFIG_SYSCTL */
 237
 238 static int udplite_kmemdup_sysctl_table(struct nf_proto_net *pn,
 239                                         struct udplite_net *un)
 240 {
 241 #ifdef CONFIG_SYSCTL
 242         if (pn->ctl_table)
 243                 return 0;
 244
 245         pn->ctl_table = kmemdup(udplite_sysctl_table,
 246                                 sizeof(udplite_sysctl_table),
 247                                 GFP_KERNEL);
 248         if (!pn->ctl_table)
 249                 return -ENOMEM;
 250
 251         pn->ctl_table[0].data = &un->timeouts[UDPLITE_CT_UNREPLIED];
 252         pn->ctl_table[1].data = &un->timeouts[UDPLITE_CT_REPLIED];
 253 #endif
 254         return 0;
 255 }
 256
 257 static int udplite_init_net(struct net *net, u_int16_t proto)
 258 {
 259         struct udplite_net *un = udplite_pernet(net);
 260         struct nf_proto_net *pn = &un->pn;
 261
 262         if (!pn->users) {
 263                 int i;
 264
 265                 for (i = 0 ; i < UDPLITE_CT_MAX; i++)
 266                         un->timeouts[i] = udplite_timeouts[i];
 267         }
 268
 269         return udplite_kmemdup_sysctl_table(pn, un);
 270 }
 271
 272 static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite4 __read_mostly =
 273 {
 274         .l3proto                = PF_INET,
 275         .l4proto                = IPPROTO_UDPLITE,
 276         .name                   = "udplite",
 277         .pkt_to_tuple           = udplite_pkt_to_tuple,
 278         .invert_tuple           = udplite_invert_tuple,
 279         .print_tuple            = udplite_print_tuple,
 280         .packet                 = udplite_packet,
 281         .get_timeouts           = udplite_get_timeouts,
 282         .new                    = udplite_new,
 283         .error                  = udplite_error,
 284 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 285         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 286         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 287         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 288         .nla_policy             = nf_ct_port_nla_policy,
 289 #endif
 290 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 291         .ctnl_timeout           = {
 292                 .nlattr_to_obj  = udplite_timeout_nlattr_to_obj,
 293                 .obj_to_nlattr  = udplite_timeout_obj_to_nlattr,
 294                 .nlattr_max     = CTA_TIMEOUT_UDPLITE_MAX,
 295                 .obj_size       = sizeof(unsigned int) *
 296                                         CTA_TIMEOUT_UDPLITE_MAX,
 297                 .nla_policy     = udplite_timeout_nla_policy,
 298         },
 299 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 300         .net_id                 = &udplite_net_id,
 301         .init_net               = udplite_init_net,
 302 };
 303
 304 static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite6 __read_mostly =
 305 {
 306         .l3proto                = PF_INET6,
 307         .l4proto                = IPPROTO_UDPLITE,
 308         .name                   = "udplite",
 309         .pkt_to_tuple           = udplite_pkt_to_tuple,
 310         .invert_tuple           = udplite_invert_tuple,
 311         .print_tuple            = udplite_print_tuple,
 312         .packet                 = udplite_packet,
 313         .get_timeouts           = udplite_get_timeouts,
 314         .new                    = udplite_new,
 315         .error                  = udplite_error,
 316 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 317         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 318         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 319         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 320         .nla_policy             = nf_ct_port_nla_policy,
 321 #endif
 322 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 323         .ctnl_timeout           = {
 324                 .nlattr_to_obj  = udplite_timeout_nlattr_to_obj,
 325                 .obj_to_nlattr  = udplite_timeout_obj_to_nlattr,
 326                 .nlattr_max     = CTA_TIMEOUT_UDPLITE_MAX,
 327                 .obj_size       = sizeof(unsigned int) *
 328                                         CTA_TIMEOUT_UDPLITE_MAX,
 329                 .nla_policy     = udplite_timeout_nla_policy,
 330         },
 331 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 332         .net_id                 = &udplite_net_id,
 333         .init_net               = udplite_init_net,
 334 };
 335
 336 static int udplite_net_init(struct net *net)
 337 {
 338         int ret = 0;
 339
 340         ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_udplite4);
 341         if (ret < 0) {
 342                 pr_err("nf_conntrack_udplite4: pernet registration failed.\n");
 343                 goto out;
 344         }
 345         ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_udplite6);
 346         if (ret < 0) {
 347                 pr_err("nf_conntrack_udplite6: pernet registration failed.\n");
 348                 goto cleanup_udplite4;
 349         }
 350         return 0;
 351
 352 cleanup_udplite4:
 353         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udplite4);
 354 out:
 355         return ret;
 356 }
 357
 358 static void udplite_net_exit(struct net *net)
 359 {
 360         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udplite6);
 361         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udplite4);
 362 }
 363
 364 static struct pernet_operations udplite_net_ops = {
 365         .init = udplite_net_init,
 366         .exit = udplite_net_exit,
 367         .id   = &udplite_net_id,
 368         .size = sizeof(struct udplite_net),
 369 };
 370
 371 static int __init nf_conntrack_proto_udplite_init(void)
 372 {
 373         int ret;
 374
 375         ret = register_pernet_subsys(&udplite_net_ops);
 376         if (ret < 0)
 377                 goto out_pernet;
 378
 379         ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_udplite4);
 380         if (ret < 0)
 381                 goto out_udplite4;
 382
 383         ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_udplite6);
 384         if (ret < 0)
 385                 goto out_udplite6;
 386
 387         return 0;
 388 out_udplite6:
 389         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
 390 out_udplite4:
 391         unregister_pernet_subsys(&udplite_net_ops);
 392 out_pernet:
 393         return ret;
 394 }
 395
 396 static void __exit nf_conntrack_proto_udplite_exit(void)
 397 {
 398         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udplite6);
 399         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
 400         unregister_pernet_subsys(&udplite_net_ops);
 401 }
 402
 403 module_init(nf_conntrack_proto_udplite_init);
 404 module_exit(nf_conntrack_proto_udplite_exit);
 405
 406 MODULE_LICENSE("GPL");