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
  15 static unsigned int nf_ct_generic_timeout __read_mostly = 600*HZ;
  16
  17 static bool nf_generic_should_process(u8 proto)
  18 {
  19         switch (proto) {
  20 #ifdef CONFIG_NF_CT_PROTO_GRE_MODULE
  21         case IPPROTO_GRE:
  22                 return false;
  23 #endif
  24         default:
  25                 return true;
  26         }
  27 }
  28
  29 static inline struct nf_generic_net *generic_pernet(struct net *net)
  30 {
  31         return &net->ct.nf_ct_proto.generic;
  32 }
  33
  34 static bool generic_pkt_to_tuple(const struct sk_buff *skb,
  35                                  unsigned int dataoff,
  36                                  struct net *net, struct nf_conntrack_tuple *tuple)
  37 {
  38         tuple->src.u.all = 0;
  39         tuple->dst.u.all = 0;
  40
  41         return true;
  42 }
  43
  44 static bool generic_invert_tuple(struct nf_conntrack_tuple *tuple,
  45                                  const struct nf_conntrack_tuple *orig)
  46 {
  47         tuple->src.u.all = 0;
  48         tuple->dst.u.all = 0;
  49
  50         return true;
  51 }
  52
  53 static unsigned int *generic_get_timeouts(struct net *net)
  54 {
  55         return &(generic_pernet(net)->timeout);
  56 }
  57
  58 /* Returns verdict for packet, or -1 for invalid. */
  59 static int generic_packet(struct nf_conn *ct,
  60                           const struct sk_buff *skb,
  61                           unsigned int dataoff,
  62                           enum ip_conntrack_info ctinfo,
  63                           u_int8_t pf,
  64                           unsigned int *timeout)
  65 {
  66         nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
  67         return NF_ACCEPT;
  68 }
  69
  70 /* Called when a new connection for this protocol found. */
  71 static bool generic_new(struct nf_conn *ct, const struct sk_buff *skb,
  72                         unsigned int dataoff, unsigned int *timeouts)
  73 {
  74         bool ret;
  75
  76         ret = nf_generic_should_process(nf_ct_protonum(ct));
  77         if (!ret)
  78                 pr_warn_once("conntrack: generic helper won't handle protocol %d. Please consider loading the specific helper module.\n",
  79                              nf_ct_protonum(ct));
  80         return ret;
  81 }
  82
  83 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
  84
  85 #include <linux/netfilter/nfnetlink.h>
  86 #include <linux/netfilter/nfnetlink_cttimeout.h>
  87
  88 static int generic_timeout_nlattr_to_obj(struct nlattr *tb[],
  89                                          struct net *net, void *data)
  90 {
  91         unsigned int *timeout = data;
  92         struct nf_generic_net *gn = generic_pernet(net);
  93
  94         if (tb[CTA_TIMEOUT_GENERIC_TIMEOUT])
  95                 *timeout =
  96                     ntohl(nla_get_be32(tb[CTA_TIMEOUT_GENERIC_TIMEOUT])) * HZ;
  97         else {
  98                 /* Set default generic timeout. */
  99                 *timeout = gn->timeout;
 100         }
 101
 102         return 0;
 103 }
 104
 105 static int
 106 generic_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 107 {
 108         const unsigned int *timeout = data;
 109
 110         if (nla_put_be32(skb, CTA_TIMEOUT_GENERIC_TIMEOUT, htonl(*timeout / HZ)))
 111                 goto nla_put_failure;
 112
 113         return 0;
 114
 115 nla_put_failure:
 116         return -ENOSPC;
 117 }
 118
 119 static const struct nla_policy
 120 generic_timeout_nla_policy[CTA_TIMEOUT_GENERIC_MAX+1] = {
 121         [CTA_TIMEOUT_GENERIC_TIMEOUT]   = { .type = NLA_U32 },
 122 };
 123 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 124
 125 #ifdef CONFIG_SYSCTL
 126 static struct ctl_table generic_sysctl_table[] = {
 127         {
 128                 .procname       = "nf_conntrack_generic_timeout",
 129                 .maxlen         = sizeof(unsigned int),
 130                 .mode           = 0644,
 131                 .proc_handler   = proc_dointvec_jiffies,
 132         },
 133         { }
 134 };
 135 #endif /* CONFIG_SYSCTL */
 136
 137 static int generic_kmemdup_sysctl_table(struct nf_proto_net *pn,
 138                                         struct nf_generic_net *gn)
 139 {
 140 #ifdef CONFIG_SYSCTL
 141         pn->ctl_table = kmemdup(generic_sysctl_table,
 142                                 sizeof(generic_sysctl_table),
 143                                 GFP_KERNEL);
 144         if (!pn->ctl_table)
 145                 return -ENOMEM;
 146
 147         pn->ctl_table[0].data = &gn->timeout;
 148 #endif
 149         return 0;
 150 }
 151
 152 static int generic_init_net(struct net *net, u_int16_t proto)
 153 {
 154         struct nf_generic_net *gn = generic_pernet(net);
 155         struct nf_proto_net *pn = &gn->pn;
 156
 157         gn->timeout = nf_ct_generic_timeout;
 158
 159         return generic_kmemdup_sysctl_table(pn, gn);
 160 }
 161
 162 static struct nf_proto_net *generic_get_net_proto(struct net *net)
 163 {
 164         return &net->ct.nf_ct_proto.generic.pn;
 165 }
 166
 167 struct nf_conntrack_l4proto nf_conntrack_l4proto_generic __read_mostly =
 168 {
 169         .l3proto                = PF_UNSPEC,
 170         .l4proto                = 255,
 171         .pkt_to_tuple           = generic_pkt_to_tuple,
 172         .invert_tuple           = generic_invert_tuple,
 173         .packet                 = generic_packet,
 174         .get_timeouts           = generic_get_timeouts,
 175         .new                    = generic_new,
 176 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 177         .ctnl_timeout           = {
 178                 .nlattr_to_obj  = generic_timeout_nlattr_to_obj,
 179                 .obj_to_nlattr  = generic_timeout_obj_to_nlattr,
 180                 .nlattr_max     = CTA_TIMEOUT_GENERIC_MAX,
 181                 .obj_size       = sizeof(unsigned int),
 182                 .nla_policy     = generic_timeout_nla_policy,
 183         },
 184 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 185         .init_net               = generic_init_net,
 186         .get_net_proto          = generic_get_net_proto,
 187 };