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                           struct sk_buff *skb,
  48                           unsigned int dataoff,
  49                           enum ip_conntrack_info ctinfo,
  50                           const struct nf_hook_state *state)
  51 {
  52         const unsigned int *timeout = nf_ct_timeout_lookup(ct);
  53
  54         if (!nf_generic_should_process(nf_ct_protonum(ct))) {
  55                 pr_warn_once("conntrack: generic helper won't handle protocol %d. Please consider loading the specific helper module.\n",
  56                              nf_ct_protonum(ct));
  57                 return -NF_ACCEPT;
  58         }
  59
  60         if (!timeout)
  61                 timeout = &generic_pernet(nf_ct_net(ct))->timeout;
  62
  63         nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
  64         return NF_ACCEPT;
  65 }
  66
  67 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
  68
  69 #include <linux/netfilter/nfnetlink.h>
  70 #include <linux/netfilter/nfnetlink_cttimeout.h>
  71
  72 static int generic_timeout_nlattr_to_obj(struct nlattr *tb[],
  73                                          struct net *net, void *data)
  74 {
  75         struct nf_generic_net *gn = generic_pernet(net);
  76         unsigned int *timeout = data;
  77
  78         if (!timeout)
  79                 timeout = &gn->timeout;
  80
  81         if (tb[CTA_TIMEOUT_GENERIC_TIMEOUT])
  82                 *timeout =
  83                     ntohl(nla_get_be32(tb[CTA_TIMEOUT_GENERIC_TIMEOUT])) * HZ;
  84         else {
  85                 /* Set default generic timeout. */
  86                 *timeout = gn->timeout;
  87         }
  88
  89         return 0;
  90 }
  91
  92 static int
  93 generic_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
  94 {
  95         const unsigned int *timeout = data;
  96
  97         if (nla_put_be32(skb, CTA_TIMEOUT_GENERIC_TIMEOUT, htonl(*timeout / HZ)))
  98                 goto nla_put_failure;
  99
 100         return 0;
 101
 102 nla_put_failure:
 103         return -ENOSPC;
 104 }
 105
 106 static const struct nla_policy
 107 generic_timeout_nla_policy[CTA_TIMEOUT_GENERIC_MAX+1] = {
 108         [CTA_TIMEOUT_GENERIC_TIMEOUT]   = { .type = NLA_U32 },
 109 };
 110 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 111
 112 #ifdef CONFIG_SYSCTL
 113 static struct ctl_table generic_sysctl_table[] = {
 114         {
 115                 .procname       = "nf_conntrack_generic_timeout",
 116                 .maxlen         = sizeof(unsigned int),
 117                 .mode           = 0644,
 118                 .proc_handler   = proc_dointvec_jiffies,
 119         },
 120         { }
 121 };
 122 #endif /* CONFIG_SYSCTL */
 123
 124 static int generic_kmemdup_sysctl_table(struct nf_proto_net *pn,
 125                                         struct nf_generic_net *gn)
 126 {
 127 #ifdef CONFIG_SYSCTL
 128         pn->ctl_table = kmemdup(generic_sysctl_table,
 129                                 sizeof(generic_sysctl_table),
 130                                 GFP_KERNEL);
 131         if (!pn->ctl_table)
 132                 return -ENOMEM;
 133
 134         pn->ctl_table[0].data = &gn->timeout;
 135 #endif
 136         return 0;
 137 }
 138
 139 static int generic_init_net(struct net *net)
 140 {
 141         struct nf_generic_net *gn = generic_pernet(net);
 142         struct nf_proto_net *pn = &gn->pn;
 143
 144         gn->timeout = nf_ct_generic_timeout;
 145
 146         return generic_kmemdup_sysctl_table(pn, gn);
 147 }
 148
 149 static struct nf_proto_net *generic_get_net_proto(struct net *net)
 150 {
 151         return &net->ct.nf_ct_proto.generic.pn;
 152 }
 153
 154 const struct nf_conntrack_l4proto nf_conntrack_l4proto_generic =
 155 {
 156         .l4proto                = 255,
 157         .pkt_to_tuple           = generic_pkt_to_tuple,
 158         .packet                 = generic_packet,
 159 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 160         .ctnl_timeout           = {
 161                 .nlattr_to_obj  = generic_timeout_nlattr_to_obj,
 162                 .obj_to_nlattr  = generic_timeout_obj_to_nlattr,
 163                 .nlattr_max     = CTA_TIMEOUT_GENERIC_MAX,
 164                 .obj_size       = sizeof(unsigned int),
 165                 .nla_policy     = generic_timeout_nla_policy,
 166         },
 167 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 168         .init_net               = generic_init_net,
 169         .get_net_proto          = generic_get_net_proto,
 170 };