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 nf_conntrack_tuple *tuple)
  52 {
  53         const struct udphdr *hp;
  54         struct udphdr _hdr;
  55
  56         hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
  57         if (hp == NULL)
  58                 return false;
  59
  60         tuple->src.u.udp.port = hp->source;
  61         tuple->dst.u.udp.port = hp->dest;
  62         return true;
  63 }
  64
  65 static bool udplite_invert_tuple(struct nf_conntrack_tuple *tuple,
  66                                  const struct nf_conntrack_tuple *orig)
  67 {
  68         tuple->src.u.udp.port = orig->dst.u.udp.port;
  69         tuple->dst.u.udp.port = orig->src.u.udp.port;
  70         return true;
  71 }
  72
  73 /* Print out the per-protocol part of the tuple. */
  74 static int udplite_print_tuple(struct seq_file *s,
  75                                const struct nf_conntrack_tuple *tuple)
  76 {
  77         return seq_printf(s, "sport=%hu dport=%hu ",
  78                           ntohs(tuple->src.u.udp.port),
  79                           ntohs(tuple->dst.u.udp.port));
  80 }
  81
  82 static unsigned int *udplite_get_timeouts(struct net *net)
  83 {
  84         return udplite_pernet(net)->timeouts;
  85 }
  86
  87 /* Returns verdict for packet, and may modify conntracktype */
  88 static int udplite_packet(struct nf_conn *ct,
  89                           const struct sk_buff *skb,
  90                           unsigned int dataoff,
  91                           enum ip_conntrack_info ctinfo,
  92                           u_int8_t pf,
  93                           unsigned int hooknum,
  94                           unsigned int *timeouts)
  95 {
  96         /* If we've seen traffic both ways, this is some kind of UDP
  97            stream.  Extend timeout. */
  98         if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
  99                 nf_ct_refresh_acct(ct, ctinfo, skb,
 100                                    timeouts[UDPLITE_CT_REPLIED]);
 101                 /* Also, more likely to be important, and not a probe */
 102                 if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
 103                         nf_conntrack_event_cache(IPCT_ASSURED, ct);
 104         } else {
 105                 nf_ct_refresh_acct(ct, ctinfo, skb,
 106                                    timeouts[UDPLITE_CT_UNREPLIED]);
 107         }
 108         return NF_ACCEPT;
 109 }
 110
 111 /* Called when a new connection for this protocol found. */
 112 static bool udplite_new(struct nf_conn *ct, const struct sk_buff *skb,
 113                         unsigned int dataoff, unsigned int *timeouts)
 114 {
 115         return true;
 116 }
 117
 118 static int udplite_error(struct net *net, struct nf_conn *tmpl,
 119                          struct sk_buff *skb,
 120                          unsigned int dataoff,
 121                          enum ip_conntrack_info *ctinfo,
 122                          u_int8_t pf,
 123                          unsigned int hooknum)
 124 {
 125         unsigned int udplen = skb->len - dataoff;
 126         const struct udphdr *hdr;
 127         struct udphdr _hdr;
 128         unsigned int cscov;
 129
 130         /* Header is too small? */
 131         hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
 132         if (hdr == NULL) {
 133                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 134                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 135                                       "nf_ct_udplite: short packet ");
 136                 return -NF_ACCEPT;
 137         }
 138
 139         cscov = ntohs(hdr->len);
 140         if (cscov == 0)
 141                 cscov = udplen;
 142         else if (cscov < sizeof(*hdr) || cscov > udplen) {
 143                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 144                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 145                                 "nf_ct_udplite: invalid checksum coverage ");
 146                 return -NF_ACCEPT;
 147         }
 148
 149         /* UDPLITE mandates checksums */
 150         if (!hdr->check) {
 151                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 152                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 153                                       "nf_ct_udplite: checksum missing ");
 154                 return -NF_ACCEPT;
 155         }
 156
 157         /* Checksum invalid? Ignore. */
 158         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 159             nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_UDP,
 160                                 pf)) {
 161                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 162                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 163                                       "nf_ct_udplite: bad UDPLite checksum ");
 164                 return -NF_ACCEPT;
 165         }
 166
 167         return NF_ACCEPT;
 168 }
 169
 170 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 171
 172 #include <linux/netfilter/nfnetlink.h>
 173 #include <linux/netfilter/nfnetlink_cttimeout.h>
 174
 175 static int udplite_timeout_nlattr_to_obj(struct nlattr *tb[],
 176                                          struct net *net, void *data)
 177 {
 178         unsigned int *timeouts = data;
 179         struct udplite_net *un = udplite_pernet(net);
 180
 181         /* set default timeouts for UDPlite. */
 182         timeouts[UDPLITE_CT_UNREPLIED] = un->timeouts[UDPLITE_CT_UNREPLIED];
 183         timeouts[UDPLITE_CT_REPLIED] = un->timeouts[UDPLITE_CT_REPLIED];
 184
 185         if (tb[CTA_TIMEOUT_UDPLITE_UNREPLIED]) {
 186                 timeouts[UDPLITE_CT_UNREPLIED] =
 187                   ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDPLITE_UNREPLIED])) * HZ;
 188         }
 189         if (tb[CTA_TIMEOUT_UDPLITE_REPLIED]) {
 190                 timeouts[UDPLITE_CT_REPLIED] =
 191                   ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDPLITE_REPLIED])) * HZ;
 192         }
 193         return 0;
 194 }
 195
 196 static int
 197 udplite_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 198 {
 199         const unsigned int *timeouts = data;
 200
 201         if (nla_put_be32(skb, CTA_TIMEOUT_UDPLITE_UNREPLIED,
 202                          htonl(timeouts[UDPLITE_CT_UNREPLIED] / HZ)) ||
 203             nla_put_be32(skb, CTA_TIMEOUT_UDPLITE_REPLIED,
 204                          htonl(timeouts[UDPLITE_CT_REPLIED] / HZ)))
 205                 goto nla_put_failure;
 206         return 0;
 207
 208 nla_put_failure:
 209         return -ENOSPC;
 210 }
 211
 212 static const struct nla_policy
 213 udplite_timeout_nla_policy[CTA_TIMEOUT_UDPLITE_MAX+1] = {
 214         [CTA_TIMEOUT_UDPLITE_UNREPLIED] = { .type = NLA_U32 },
 215         [CTA_TIMEOUT_UDPLITE_REPLIED]   = { .type = NLA_U32 },
 216 };
 217 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 218
 219 #ifdef CONFIG_SYSCTL
 220 static struct ctl_table udplite_sysctl_table[] = {
 221         {
 222                 .procname       = "nf_conntrack_udplite_timeout",
 223                 .maxlen         = sizeof(unsigned int),
 224                 .mode           = 0644,
 225                 .proc_handler   = proc_dointvec_jiffies,
 226         },
 227         {
 228                 .procname       = "nf_conntrack_udplite_timeout_stream",
 229                 .maxlen         = sizeof(unsigned int),
 230                 .mode           = 0644,
 231                 .proc_handler   = proc_dointvec_jiffies,
 232         },
 233         { }
 234 };
 235 #endif /* CONFIG_SYSCTL */
 236
 237 static int udplite_init_net(struct net *net)
 238 {
 239         int i;
 240         struct udplite_net *un = udplite_pernet(net);
 241         struct nf_proto_net *pn = (struct nf_proto_net *)un;
 242 #ifdef CONFIG_SYSCTL
 243         if (!pn->ctl_table) {
 244 #else
 245         if (!pn->users++) {
 246 #endif
 247                 for (i = 0 ; i < UDPLITE_CT_MAX; i++)
 248                         un->timeouts[i] = udplite_timeouts[i];
 249 #ifdef CONFIG_SYSCTL
 250                 pn->ctl_table = kmemdup(udplite_sysctl_table,
 251                                         sizeof(udplite_sysctl_table),
 252                                         GFP_KERNEL);
 253                 if (!pn->ctl_table)
 254                         return -ENOMEM;
 255                 pn->ctl_table[0].data = &un->timeouts[UDPLITE_CT_UNREPLIED];
 256                 pn->ctl_table[1].data = &un->timeouts[UDPLITE_CT_REPLIED];
 257 #endif
 258         }
 259         return 0;
 260 }
 261
 262 static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite4 __read_mostly =
 263 {
 264         .l3proto                = PF_INET,
 265         .l4proto                = IPPROTO_UDPLITE,
 266         .name                   = "udplite",
 267         .pkt_to_tuple           = udplite_pkt_to_tuple,
 268         .invert_tuple           = udplite_invert_tuple,
 269         .print_tuple            = udplite_print_tuple,
 270         .packet                 = udplite_packet,
 271         .get_timeouts           = udplite_get_timeouts,
 272         .new                    = udplite_new,
 273         .error                  = udplite_error,
 274 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 275         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 276         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 277         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 278         .nla_policy             = nf_ct_port_nla_policy,
 279 #endif
 280 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 281         .ctnl_timeout           = {
 282                 .nlattr_to_obj  = udplite_timeout_nlattr_to_obj,
 283                 .obj_to_nlattr  = udplite_timeout_obj_to_nlattr,
 284                 .nlattr_max     = CTA_TIMEOUT_UDPLITE_MAX,
 285                 .obj_size       = sizeof(unsigned int) *
 286                                         CTA_TIMEOUT_UDPLITE_MAX,
 287                 .nla_policy     = udplite_timeout_nla_policy,
 288         },
 289 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 290         .net_id                 = &udplite_net_id,
 291         .init_net               = udplite_init_net,
 292 };
 293
 294 static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite6 __read_mostly =
 295 {
 296         .l3proto                = PF_INET6,
 297         .l4proto                = IPPROTO_UDPLITE,
 298         .name                   = "udplite",
 299         .pkt_to_tuple           = udplite_pkt_to_tuple,
 300         .invert_tuple           = udplite_invert_tuple,
 301         .print_tuple            = udplite_print_tuple,
 302         .packet                 = udplite_packet,
 303         .get_timeouts           = udplite_get_timeouts,
 304         .new                    = udplite_new,
 305         .error                  = udplite_error,
 306 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 307         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 308         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 309         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 310         .nla_policy             = nf_ct_port_nla_policy,
 311 #endif
 312 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 313         .ctnl_timeout           = {
 314                 .nlattr_to_obj  = udplite_timeout_nlattr_to_obj,
 315                 .obj_to_nlattr  = udplite_timeout_obj_to_nlattr,
 316                 .nlattr_max     = CTA_TIMEOUT_UDPLITE_MAX,
 317                 .obj_size       = sizeof(unsigned int) *
 318                                         CTA_TIMEOUT_UDPLITE_MAX,
 319                 .nla_policy     = udplite_timeout_nla_policy,
 320         },
 321 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 322         .net_id                 = &udplite_net_id,
 323         .init_net               = udplite_init_net,
 324 };
 325
 326 static int udplite_net_init(struct net *net)
 327 {
 328         int ret = 0;
 329
 330         ret = nf_conntrack_l4proto_register(net,
 331                                             &nf_conntrack_l4proto_udplite4);
 332         if (ret < 0) {
 333                 pr_err("nf_conntrack_l4proto_udplite4 :protocol register failed.\n");
 334                 goto out;
 335         }
 336         ret = nf_conntrack_l4proto_register(net,
 337                                             &nf_conntrack_l4proto_udplite6);
 338         if (ret < 0) {
 339                 pr_err("nf_conntrack_l4proto_udplite4 :protocol register failed.\n");
 340                 goto cleanup_udplite4;
 341         }
 342         return 0;
 343
 344 cleanup_udplite4:
 345         nf_conntrack_l4proto_unregister(net, &nf_conntrack_l4proto_udplite4);
 346 out:
 347         return ret;
 348 }
 349
 350 static void udplite_net_exit(struct net *net)
 351 {
 352         nf_conntrack_l4proto_unregister(net, &nf_conntrack_l4proto_udplite6);
 353         nf_conntrack_l4proto_unregister(net, &nf_conntrack_l4proto_udplite4);
 354 }
 355
 356 static struct pernet_operations udplite_net_ops = {
 357         .init = udplite_net_init,
 358         .exit = udplite_net_exit,
 359         .id   = &udplite_net_id,
 360         .size = sizeof(struct udplite_net),
 361 };
 362
 363 static int __init nf_conntrack_proto_udplite_init(void)
 364 {
 365         return register_pernet_subsys(&udplite_net_ops);
 366 }
 367
 368 static void __exit nf_conntrack_proto_udplite_exit(void)
 369 {
 370         unregister_pernet_subsys(&udplite_net_ops);
 371 }
 372
 373 module_init(nf_conntrack_proto_udplite_init);
 374 module_exit(nf_conntrack_proto_udplite_exit);
 375
 376 MODULE_LICENSE("GPL");