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 bool udplite_pkt_to_tuple(const struct sk_buff *skb,
  39                                  unsigned int dataoff,
  40                                  struct nf_conntrack_tuple *tuple)
  41 {
  42         const struct udphdr *hp;
  43         struct udphdr _hdr;
  44
  45         hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
  46         if (hp == NULL)
  47                 return false;
  48
  49         tuple->src.u.udp.port = hp->source;
  50         tuple->dst.u.udp.port = hp->dest;
  51         return true;
  52 }
  53
  54 static bool udplite_invert_tuple(struct nf_conntrack_tuple *tuple,
  55                                  const struct nf_conntrack_tuple *orig)
  56 {
  57         tuple->src.u.udp.port = orig->dst.u.udp.port;
  58         tuple->dst.u.udp.port = orig->src.u.udp.port;
  59         return true;
  60 }
  61
  62 /* Print out the per-protocol part of the tuple. */
  63 static int udplite_print_tuple(struct seq_file *s,
  64                                const struct nf_conntrack_tuple *tuple)
  65 {
  66         return seq_printf(s, "sport=%hu dport=%hu ",
  67                           ntohs(tuple->src.u.udp.port),
  68                           ntohs(tuple->dst.u.udp.port));
  69 }
  70
  71 static unsigned int *udplite_get_timeouts(struct net *net)
  72 {
  73         return udplite_timeouts;
  74 }
  75
  76 /* Returns verdict for packet, and may modify conntracktype */
  77 static int udplite_packet(struct nf_conn *ct,
  78                           const struct sk_buff *skb,
  79                           unsigned int dataoff,
  80                           enum ip_conntrack_info ctinfo,
  81                           u_int8_t pf,
  82                           unsigned int hooknum,
  83                           unsigned int *timeouts)
  84 {
  85         /* If we've seen traffic both ways, this is some kind of UDP
  86            stream.  Extend timeout. */
  87         if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
  88                 nf_ct_refresh_acct(ct, ctinfo, skb,
  89                                    timeouts[UDPLITE_CT_REPLIED]);
  90                 /* Also, more likely to be important, and not a probe */
  91                 if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
  92                         nf_conntrack_event_cache(IPCT_ASSURED, ct);
  93         } else {
  94                 nf_ct_refresh_acct(ct, ctinfo, skb,
  95                                    timeouts[UDPLITE_CT_UNREPLIED]);
  96         }
  97         return NF_ACCEPT;
  98 }
  99
 100 /* Called when a new connection for this protocol found. */
 101 static bool udplite_new(struct nf_conn *ct, const struct sk_buff *skb,
 102                         unsigned int dataoff, unsigned int *timeouts)
 103 {
 104         return true;
 105 }
 106
 107 static int udplite_error(struct net *net, struct nf_conn *tmpl,
 108                          struct sk_buff *skb,
 109                          unsigned int dataoff,
 110                          enum ip_conntrack_info *ctinfo,
 111                          u_int8_t pf,
 112                          unsigned int hooknum)
 113 {
 114         unsigned int udplen = skb->len - dataoff;
 115         const struct udphdr *hdr;
 116         struct udphdr _hdr;
 117         unsigned int cscov;
 118
 119         /* Header is too small? */
 120         hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
 121         if (hdr == NULL) {
 122                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 123                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 124                                       "nf_ct_udplite: short packet ");
 125                 return -NF_ACCEPT;
 126         }
 127
 128         cscov = ntohs(hdr->len);
 129         if (cscov == 0)
 130                 cscov = udplen;
 131         else if (cscov < sizeof(*hdr) || cscov > udplen) {
 132                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 133                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 134                                 "nf_ct_udplite: invalid checksum coverage ");
 135                 return -NF_ACCEPT;
 136         }
 137
 138         /* UDPLITE mandates checksums */
 139         if (!hdr->check) {
 140                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 141                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 142                                       "nf_ct_udplite: checksum missing ");
 143                 return -NF_ACCEPT;
 144         }
 145
 146         /* Checksum invalid? Ignore. */
 147         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 148             nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_UDP,
 149                                 pf)) {
 150                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 151                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 152                                       "nf_ct_udplite: bad UDPLite checksum ");
 153                 return -NF_ACCEPT;
 154         }
 155
 156         return NF_ACCEPT;
 157 }
 158
 159 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 160
 161 #include <linux/netfilter/nfnetlink.h>
 162 #include <linux/netfilter/nfnetlink_cttimeout.h>
 163
 164 static int udplite_timeout_nlattr_to_obj(struct nlattr *tb[], void *data)
 165 {
 166         unsigned int *timeouts = data;
 167
 168         /* set default timeouts for UDPlite. */
 169         timeouts[UDPLITE_CT_UNREPLIED] = udplite_timeouts[UDPLITE_CT_UNREPLIED];
 170         timeouts[UDPLITE_CT_REPLIED] = udplite_timeouts[UDPLITE_CT_REPLIED];
 171
 172         if (tb[CTA_TIMEOUT_UDPLITE_UNREPLIED]) {
 173                 timeouts[UDPLITE_CT_UNREPLIED] =
 174                   ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDPLITE_UNREPLIED])) * HZ;
 175         }
 176         if (tb[CTA_TIMEOUT_UDPLITE_REPLIED]) {
 177                 timeouts[UDPLITE_CT_REPLIED] =
 178                   ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDPLITE_REPLIED])) * HZ;
 179         }
 180         return 0;
 181 }
 182
 183 static int
 184 udplite_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 185 {
 186         const unsigned int *timeouts = data;
 187
 188         NLA_PUT_BE32(skb, CTA_TIMEOUT_UDPLITE_UNREPLIED,
 189                         htonl(timeouts[UDPLITE_CT_UNREPLIED] / HZ));
 190         NLA_PUT_BE32(skb, CTA_TIMEOUT_UDPLITE_REPLIED,
 191                         htonl(timeouts[UDPLITE_CT_REPLIED] / HZ));
 192         return 0;
 193
 194 nla_put_failure:
 195         return -ENOSPC;
 196 }
 197
 198 static const struct nla_policy
 199 udplite_timeout_nla_policy[CTA_TIMEOUT_UDPLITE_MAX+1] = {
 200         [CTA_TIMEOUT_UDPLITE_UNREPLIED] = { .type = NLA_U32 },
 201         [CTA_TIMEOUT_UDPLITE_REPLIED]   = { .type = NLA_U32 },
 202 };
 203 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 204
 205 #ifdef CONFIG_SYSCTL
 206 static unsigned int udplite_sysctl_table_users;
 207 static struct ctl_table_header *udplite_sysctl_header;
 208 static struct ctl_table udplite_sysctl_table[] = {
 209         {
 210                 .procname       = "nf_conntrack_udplite_timeout",
 211                 .data           = &udplite_timeouts[UDPLITE_CT_UNREPLIED],
 212                 .maxlen         = sizeof(unsigned int),
 213                 .mode           = 0644,
 214                 .proc_handler   = proc_dointvec_jiffies,
 215         },
 216         {
 217                 .procname       = "nf_conntrack_udplite_timeout_stream",
 218                 .data           = &udplite_timeouts[UDPLITE_CT_REPLIED],
 219                 .maxlen         = sizeof(unsigned int),
 220                 .mode           = 0644,
 221                 .proc_handler   = proc_dointvec_jiffies,
 222         },
 223         { }
 224 };
 225 #endif /* CONFIG_SYSCTL */
 226
 227 static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite4 __read_mostly =
 228 {
 229         .l3proto                = PF_INET,
 230         .l4proto                = IPPROTO_UDPLITE,
 231         .name                   = "udplite",
 232         .pkt_to_tuple           = udplite_pkt_to_tuple,
 233         .invert_tuple           = udplite_invert_tuple,
 234         .print_tuple            = udplite_print_tuple,
 235         .packet                 = udplite_packet,
 236         .get_timeouts           = udplite_get_timeouts,
 237         .new                    = udplite_new,
 238         .error                  = udplite_error,
 239 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 240         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 241         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 242         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 243         .nla_policy             = nf_ct_port_nla_policy,
 244 #endif
 245 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 246         .ctnl_timeout           = {
 247                 .nlattr_to_obj  = udplite_timeout_nlattr_to_obj,
 248                 .obj_to_nlattr  = udplite_timeout_obj_to_nlattr,
 249                 .nlattr_max     = CTA_TIMEOUT_UDPLITE_MAX,
 250                 .obj_size       = sizeof(unsigned int) *
 251                                         CTA_TIMEOUT_UDPLITE_MAX,
 252                 .nla_policy     = udplite_timeout_nla_policy,
 253         },
 254 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 255 #ifdef CONFIG_SYSCTL
 256         .ctl_table_users        = &udplite_sysctl_table_users,
 257         .ctl_table_header       = &udplite_sysctl_header,
 258         .ctl_table              = udplite_sysctl_table,
 259 #endif
 260 };
 261
 262 static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite6 __read_mostly =
 263 {
 264         .l3proto                = PF_INET6,
 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 #ifdef CONFIG_SYSCTL
 291         .ctl_table_users        = &udplite_sysctl_table_users,
 292         .ctl_table_header       = &udplite_sysctl_header,
 293         .ctl_table              = udplite_sysctl_table,
 294 #endif
 295 };
 296
 297 static int __init nf_conntrack_proto_udplite_init(void)
 298 {
 299         int err;
 300
 301         err = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udplite4);
 302         if (err < 0)
 303                 goto err1;
 304         err = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udplite6);
 305         if (err < 0)
 306                 goto err2;
 307         return 0;
 308 err2:
 309         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
 310 err1:
 311         return err;
 312 }
 313
 314 static void __exit nf_conntrack_proto_udplite_exit(void)
 315 {
 316         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite6);
 317         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
 318 }
 319
 320 module_init(nf_conntrack_proto_udplite_init);
 321 module_exit(nf_conntrack_proto_udplite_exit);
 322
 323 MODULE_LICENSE("GPL");