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_SCTP_MODULE
  21         case IPPROTO_SCTP:
  22                 return false;
  23 #endif
  24 #ifdef CONFIG_NF_CT_PROTO_DCCP_MODULE
  25         case IPPROTO_DCCP:
  26                 return false;
  27 #endif
  28 #ifdef CONFIG_NF_CT_PROTO_GRE_MODULE
  29         case IPPROTO_GRE:
  30                 return false;
  31 #endif
  32 #ifdef CONFIG_NF_CT_PROTO_UDPLITE_MODULE
  33         case IPPROTO_UDPLITE:
  34                 return false;
  35 #endif
  36         default:
  37                 return true;
  38         }
  39 }
  40
  41 static inline struct nf_generic_net *generic_pernet(struct net *net)
  42 {
  43         return &net->ct.nf_ct_proto.generic;
  44 }
  45
  46 static bool generic_pkt_to_tuple(const struct sk_buff *skb,
  47                                  unsigned int dataoff,
  48                                  struct net *net, struct nf_conntrack_tuple *tuple)
  49 {
  50         tuple->src.u.all = 0;
  51         tuple->dst.u.all = 0;
  52
  53         return true;
  54 }
  55
  56 static bool generic_invert_tuple(struct nf_conntrack_tuple *tuple,
  57                                  const struct nf_conntrack_tuple *orig)
  58 {
  59         tuple->src.u.all = 0;
  60         tuple->dst.u.all = 0;
  61
  62         return true;
  63 }
  64
  65 /* Print out the per-protocol part of the tuple. */
  66 static void generic_print_tuple(struct seq_file *s,
  67                                 const struct nf_conntrack_tuple *tuple)
  68 {
  69 }
  70
  71 static unsigned int *generic_get_timeouts(struct net *net)
  72 {
  73         return &(generic_pernet(net)->timeout);
  74 }
  75
  76 /* Returns verdict for packet, or -1 for invalid. */
  77 static int generic_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 *timeout)
  84 {
  85         nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
  86         return NF_ACCEPT;
  87 }
  88
  89 /* Called when a new connection for this protocol found. */
  90 static bool generic_new(struct nf_conn *ct, const struct sk_buff *skb,
  91                         unsigned int dataoff, unsigned int *timeouts)
  92 {
  93         bool ret;
  94
  95         ret = nf_generic_should_process(nf_ct_protonum(ct));
  96         if (!ret)
  97                 pr_warn_once("conntrack: generic helper won't handle protocol %d. Please consider loading the specific helper module.\n",
  98                              nf_ct_protonum(ct));
  99         return ret;
 100 }
 101
 102 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 103
 104 #include <linux/netfilter/nfnetlink.h>
 105 #include <linux/netfilter/nfnetlink_cttimeout.h>
 106
 107 static int generic_timeout_nlattr_to_obj(struct nlattr *tb[],
 108                                          struct net *net, void *data)
 109 {
 110         unsigned int *timeout = data;
 111         struct nf_generic_net *gn = generic_pernet(net);
 112
 113         if (tb[CTA_TIMEOUT_GENERIC_TIMEOUT])
 114                 *timeout =
 115                     ntohl(nla_get_be32(tb[CTA_TIMEOUT_GENERIC_TIMEOUT])) * HZ;
 116         else {
 117                 /* Set default generic timeout. */
 118                 *timeout = gn->timeout;
 119         }
 120
 121         return 0;
 122 }
 123
 124 static int
 125 generic_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 126 {
 127         const unsigned int *timeout = data;
 128
 129         if (nla_put_be32(skb, CTA_TIMEOUT_GENERIC_TIMEOUT, htonl(*timeout / HZ)))
 130                 goto nla_put_failure;
 131
 132         return 0;
 133
 134 nla_put_failure:
 135         return -ENOSPC;
 136 }
 137
 138 static const struct nla_policy
 139 generic_timeout_nla_policy[CTA_TIMEOUT_GENERIC_MAX+1] = {
 140         [CTA_TIMEOUT_GENERIC_TIMEOUT]   = { .type = NLA_U32 },
 141 };
 142 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 143
 144 #ifdef CONFIG_SYSCTL
 145 static struct ctl_table generic_sysctl_table[] = {
 146         {
 147                 .procname       = "nf_conntrack_generic_timeout",
 148                 .maxlen         = sizeof(unsigned int),
 149                 .mode           = 0644,
 150                 .proc_handler   = proc_dointvec_jiffies,
 151         },
 152         { }
 153 };
 154 #endif /* CONFIG_SYSCTL */
 155
 156 static int generic_kmemdup_sysctl_table(struct nf_proto_net *pn,
 157                                         struct nf_generic_net *gn)
 158 {
 159 #ifdef CONFIG_SYSCTL
 160         pn->ctl_table = kmemdup(generic_sysctl_table,
 161                                 sizeof(generic_sysctl_table),
 162                                 GFP_KERNEL);
 163         if (!pn->ctl_table)
 164                 return -ENOMEM;
 165
 166         pn->ctl_table[0].data = &gn->timeout;
 167 #endif
 168         return 0;
 169 }
 170
 171 static int generic_init_net(struct net *net, u_int16_t proto)
 172 {
 173         struct nf_generic_net *gn = generic_pernet(net);
 174         struct nf_proto_net *pn = &gn->pn;
 175
 176         gn->timeout = nf_ct_generic_timeout;
 177
 178         return generic_kmemdup_sysctl_table(pn, gn);
 179 }
 180
 181 static struct nf_proto_net *generic_get_net_proto(struct net *net)
 182 {
 183         return &net->ct.nf_ct_proto.generic.pn;
 184 }
 185
 186 struct nf_conntrack_l4proto nf_conntrack_l4proto_generic __read_mostly =
 187 {
 188         .l3proto                = PF_UNSPEC,
 189         .l4proto                = 255,
 190         .name                   = "unknown",
 191         .pkt_to_tuple           = generic_pkt_to_tuple,
 192         .invert_tuple           = generic_invert_tuple,
 193         .print_tuple            = generic_print_tuple,
 194         .packet                 = generic_packet,
 195         .get_timeouts           = generic_get_timeouts,
 196         .new                    = generic_new,
 197 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 198         .ctnl_timeout           = {
 199                 .nlattr_to_obj  = generic_timeout_nlattr_to_obj,
 200                 .obj_to_nlattr  = generic_timeout_obj_to_nlattr,
 201                 .nlattr_max     = CTA_TIMEOUT_GENERIC_MAX,
 202                 .obj_size       = sizeof(unsigned int),
 203                 .nla_policy     = generic_timeout_nla_policy,
 204         },
 205 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 206         .init_net               = generic_init_net,
 207         .get_net_proto          = generic_get_net_proto,
 208 };