net/netfilter/nf_conntrack_proto_generic.c

   1 /* (C) 1999-2001 Paul `Rusty' Russell
   2  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/jiffies.h>
  11 #include <linux/timer.h>
  12 #include <linux/netfilter.h>
  13 #include <net/netfilter/nf_conntrack_l4proto.h>
  14 #include <net/netfilter/nf_conntrack_timeout.h>
  15
  16 static const unsigned int nf_ct_generic_timeout = 600*HZ;
  17
  18 static bool nf_generic_should_process(u8 proto)
  19 {
  20         switch (proto) {
  21 #ifdef CONFIG_NF_CT_PROTO_GRE_MODULE
  22         case IPPROTO_GRE:
  23                 return false;
  24 #endif
  25         default:
  26                 return true;
  27         }
  28 }
  29
  30 static inline struct nf_generic_net *generic_pernet(struct net *net)
  31 {
  32         return &net->ct.nf_ct_proto.generic;
  33 }
  34
  35 static bool generic_pkt_to_tuple(const struct sk_buff *skb,
  36                                  unsigned int dataoff,
  37                                  struct net *net, struct nf_conntrack_tuple *tuple)
  38 {
  39         tuple->src.u.all = 0;
  40         tuple->dst.u.all = 0;
  41
  42         return true;
  43 }
  44
  45 /* Returns verdict for packet, or -1 for invalid. */
  46 static int generic_packet(struct nf_conn *ct,
  47                           const struct sk_buff *skb,
  48                           unsigned int dataoff,
  49                           enum ip_conntrack_info ctinfo)
  50 {
  51         const unsigned int *timeout = nf_ct_timeout_lookup(ct);
  52
  53         if (!timeout)
  54                 timeout = &generic_pernet(nf_ct_net(ct))->timeout;
  55
  56         nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
  57         return NF_ACCEPT;
  58 }
  59
  60 /* Called when a new connection for this protocol found. */
  61 static bool generic_new(struct nf_conn *ct, const struct sk_buff *skb,
  62                         unsigned int dataoff)
  63 {
  64         bool ret;
  65
  66         ret = nf_generic_should_process(nf_ct_protonum(ct));
  67         if (!ret)
  68                 pr_warn_once("conntrack: generic helper won't handle protocol %d. Please consider loading the specific helper module.\n",
  69                              nf_ct_protonum(ct));
  70         return ret;
  71 }
  72
  73 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
  74
  75 #include <linux/netfilter/nfnetlink.h>
  76 #include <linux/netfilter/nfnetlink_cttimeout.h>
  77
  78 static int generic_timeout_nlattr_to_obj(struct nlattr *tb[],
  79                                          struct net *net, void *data)
  80 {
  81         struct nf_generic_net *gn = generic_pernet(net);
  82         unsigned int *timeout = data;
  83
  84         if (!timeout)
  85                 timeout = &gn->timeout;
  86
  87         if (tb[CTA_TIMEOUT_GENERIC_TIMEOUT])
  88                 *timeout =
  89                     ntohl(nla_get_be32(tb[CTA_TIMEOUT_GENERIC_TIMEOUT])) * HZ;
  90         else {
  91                 /* Set default generic timeout. */
  92                 *timeout = gn->timeout;
  93         }
  94
  95         return 0;
  96 }
  97
  98 static int
  99 generic_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 100 {
 101         const unsigned int *timeout = data;
 102
 103         if (nla_put_be32(skb, CTA_TIMEOUT_GENERIC_TIMEOUT, htonl(*timeout / HZ)))
 104                 goto nla_put_failure;
 105
 106         return 0;
 107
 108 nla_put_failure:
 109         return -ENOSPC;
 110 }
 111
 112 static const struct nla_policy
 113 generic_timeout_nla_policy[CTA_TIMEOUT_GENERIC_MAX+1] = {
 114         [CTA_TIMEOUT_GENERIC_TIMEOUT]   = { .type = NLA_U32 },
 115 };
 116 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 117
 118 #ifdef CONFIG_SYSCTL
 119 static struct ctl_table generic_sysctl_table[] = {
 120         {
 121                 .procname       = "nf_conntrack_generic_timeout",
 122                 .maxlen         = sizeof(unsigned int),
 123                 .mode           = 0644,
 124                 .proc_handler   = proc_dointvec_jiffies,
 125         },
 126         { }
 127 };
 128 #endif /* CONFIG_SYSCTL */
 129
 130 static int generic_kmemdup_sysctl_table(struct nf_proto_net *pn,
 131                                         struct nf_generic_net *gn)
 132 {
 133 #ifdef CONFIG_SYSCTL
 134         pn->ctl_table = kmemdup(generic_sysctl_table,
 135                                 sizeof(generic_sysctl_table),
 136                                 GFP_KERNEL);
 137         if (!pn->ctl_table)
 138                 return -ENOMEM;
 139
 140         pn->ctl_table[0].data = &gn->timeout;
 141 #endif
 142         return 0;
 143 }
 144
 145 static int generic_init_net(struct net *net, u_int16_t proto)
 146 {
 147         struct nf_generic_net *gn = generic_pernet(net);
 148         struct nf_proto_net *pn = &gn->pn;
 149
 150         gn->timeout = nf_ct_generic_timeout;
 151
 152         return generic_kmemdup_sysctl_table(pn, gn);
 153 }
 154
 155 static struct nf_proto_net *generic_get_net_proto(struct net *net)
 156 {
 157         return &net->ct.nf_ct_proto.generic.pn;
 158 }
 159
 160 const struct nf_conntrack_l4proto nf_conntrack_l4proto_generic =
 161 {
 162         .l3proto                = PF_UNSPEC,
 163         .l4proto                = 255,
 164         .pkt_to_tuple           = generic_pkt_to_tuple,
 165         .packet                 = generic_packet,
 166         .new                    = generic_new,
 167 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 168         .ctnl_timeout           = {
 169                 .nlattr_to_obj  = generic_timeout_nlattr_to_obj,
 170                 .obj_to_nlattr  = generic_timeout_obj_to_nlattr,
 171                 .nlattr_max     = CTA_TIMEOUT_GENERIC_MAX,
 172                 .obj_size       = sizeof(unsigned int),
 173                 .nla_policy     = generic_timeout_nla_policy,
 174         },
 175 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 176         .init_net               = generic_init_net,
 177         .get_net_proto          = generic_get_net_proto,
 178 };