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                           unsigned int *timeout)
  64 {
  65         nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
  66         return NF_ACCEPT;
  67 }
  68
  69 /* Called when a new connection for this protocol found. */
  70 static bool generic_new(struct nf_conn *ct, const struct sk_buff *skb,
  71                         unsigned int dataoff, unsigned int *timeouts)
  72 {
  73         bool ret;
  74
  75         ret = nf_generic_should_process(nf_ct_protonum(ct));
  76         if (!ret)
  77                 pr_warn_once("conntrack: generic helper won't handle protocol %d. Please consider loading the specific helper module.\n",
  78                              nf_ct_protonum(ct));
  79         return ret;
  80 }
  81
  82 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
  83
  84 #include <linux/netfilter/nfnetlink.h>
  85 #include <linux/netfilter/nfnetlink_cttimeout.h>
  86
  87 static int generic_timeout_nlattr_to_obj(struct nlattr *tb[],
  88                                          struct net *net, void *data)
  89 {
  90         unsigned int *timeout = data;
  91         struct nf_generic_net *gn = generic_pernet(net);
  92
  93         if (tb[CTA_TIMEOUT_GENERIC_TIMEOUT])
  94                 *timeout =
  95                     ntohl(nla_get_be32(tb[CTA_TIMEOUT_GENERIC_TIMEOUT])) * HZ;
  96         else {
  97                 /* Set default generic timeout. */
  98                 *timeout = gn->timeout;
  99         }
 100
 101         return 0;
 102 }
 103
 104 static int
 105 generic_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 106 {
 107         const unsigned int *timeout = data;
 108
 109         if (nla_put_be32(skb, CTA_TIMEOUT_GENERIC_TIMEOUT, htonl(*timeout / HZ)))
 110                 goto nla_put_failure;
 111
 112         return 0;
 113
 114 nla_put_failure:
 115         return -ENOSPC;
 116 }
 117
 118 static const struct nla_policy
 119 generic_timeout_nla_policy[CTA_TIMEOUT_GENERIC_MAX+1] = {
 120         [CTA_TIMEOUT_GENERIC_TIMEOUT]   = { .type = NLA_U32 },
 121 };
 122 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 123
 124 #ifdef CONFIG_SYSCTL
 125 static struct ctl_table generic_sysctl_table[] = {
 126         {
 127                 .procname       = "nf_conntrack_generic_timeout",
 128                 .maxlen         = sizeof(unsigned int),
 129                 .mode           = 0644,
 130                 .proc_handler   = proc_dointvec_jiffies,
 131         },
 132         { }
 133 };
 134 #endif /* CONFIG_SYSCTL */
 135
 136 static int generic_kmemdup_sysctl_table(struct nf_proto_net *pn,
 137                                         struct nf_generic_net *gn)
 138 {
 139 #ifdef CONFIG_SYSCTL
 140         pn->ctl_table = kmemdup(generic_sysctl_table,
 141                                 sizeof(generic_sysctl_table),
 142                                 GFP_KERNEL);
 143         if (!pn->ctl_table)
 144                 return -ENOMEM;
 145
 146         pn->ctl_table[0].data = &gn->timeout;
 147 #endif
 148         return 0;
 149 }
 150
 151 static int generic_init_net(struct net *net, u_int16_t proto)
 152 {
 153         struct nf_generic_net *gn = generic_pernet(net);
 154         struct nf_proto_net *pn = &gn->pn;
 155
 156         gn->timeout = nf_ct_generic_timeout;
 157
 158         return generic_kmemdup_sysctl_table(pn, gn);
 159 }
 160
 161 static struct nf_proto_net *generic_get_net_proto(struct net *net)
 162 {
 163         return &net->ct.nf_ct_proto.generic.pn;
 164 }
 165
 166 struct nf_conntrack_l4proto nf_conntrack_l4proto_generic __read_mostly =
 167 {
 168         .l3proto                = PF_UNSPEC,
 169         .l4proto                = 255,
 170         .pkt_to_tuple           = generic_pkt_to_tuple,
 171         .invert_tuple           = generic_invert_tuple,
 172         .packet                 = generic_packet,
 173         .get_timeouts           = generic_get_timeouts,
 174         .new                    = generic_new,
 175 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 176         .ctnl_timeout           = {
 177                 .nlattr_to_obj  = generic_timeout_nlattr_to_obj,
 178                 .obj_to_nlattr  = generic_timeout_obj_to_nlattr,
 179                 .nlattr_max     = CTA_TIMEOUT_GENERIC_MAX,
 180                 .obj_size       = sizeof(unsigned int),
 181                 .nla_policy     = generic_timeout_nla_policy,
 182         },
 183 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 184         .init_net               = generic_init_net,
 185         .get_net_proto          = generic_get_net_proto,
 186 };