release/src-rt-6.x/linux/linux-2.6/net/netfilter/nf_conntrack_proto_udp.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/timer.h>
  11 #include <linux/module.h>
  12 #include <linux/netfilter.h>
  13 #include <linux/udp.h>
  14 #include <linux/seq_file.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/ipv6.h>
  17 #include <net/ip6_checksum.h>
  18 #include <net/checksum.h>
  19
  20 #include <linux/netfilter.h>
  21 #include <linux/netfilter_ipv4.h>
  22 #include <linux/netfilter_ipv6.h>
  23 #include <net/netfilter/nf_conntrack_l4proto.h>
  24 #include <net/netfilter/nf_conntrack_ecache.h>
  25
  26 #if defined(CONFIG_BCM_NAT) || defined(CONFIG_BCM_NAT_MODULE)
  27 extern int ipv4_conntrack_fastnat;
  28 #endif
  29
  30 static unsigned int nf_ct_udp_timeout __read_mostly = 30*HZ;
  31 static unsigned int nf_ct_udp_timeout_stream __read_mostly = 180*HZ;
  32
  33 static int udp_pkt_to_tuple(const struct sk_buff *skb,
  34                              unsigned int dataoff,
  35                              struct nf_conntrack_tuple *tuple)
  36 {
  37         struct udphdr _hdr, *hp;
  38
  39         /* Actually only need first 8 bytes. */
  40         hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
  41         if (hp == NULL)
  42                 return 0;
  43
  44         tuple->src.u.udp.port = hp->source;
  45         tuple->dst.u.udp.port = hp->dest;
  46
  47         return 1;
  48 }
  49
  50 static int udp_invert_tuple(struct nf_conntrack_tuple *tuple,
  51                             const struct nf_conntrack_tuple *orig)
  52 {
  53         tuple->src.u.udp.port = orig->dst.u.udp.port;
  54         tuple->dst.u.udp.port = orig->src.u.udp.port;
  55         return 1;
  56 }
  57
  58 /* Print out the per-protocol part of the tuple. */
  59 static int udp_print_tuple(struct seq_file *s,
  60                            const struct nf_conntrack_tuple *tuple)
  61 {
  62         return seq_printf(s, "sport=%hu dport=%hu ",
  63                           ntohs(tuple->src.u.udp.port),
  64                           ntohs(tuple->dst.u.udp.port));
  65 }
  66
  67 /* Returns verdict for packet, and may modify conntracktype */
  68 static int udp_packet(struct nf_conn *conntrack,
  69                       const struct sk_buff *skb,
  70                       unsigned int dataoff,
  71                       enum ip_conntrack_info ctinfo,
  72                       int pf,
  73                       unsigned int hooknum)
  74 {
  75         /* If we've seen traffic both ways, this is some kind of UDP
  76            stream.  Extend timeout. */
  77         if (test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) {
  78                 nf_ct_refresh_acct(conntrack, ctinfo, skb,
  79                                    nf_ct_udp_timeout_stream);
  80                 /* Also, more likely to be important, and not a probe */
  81                 if (!test_and_set_bit(IPS_ASSURED_BIT, &conntrack->status))
  82                         nf_conntrack_event_cache(IPCT_STATUS, skb);
  83         } else
  84                 nf_ct_refresh_acct(conntrack, ctinfo, skb, nf_ct_udp_timeout);
  85
  86         return NF_ACCEPT;
  87 }
  88
  89 /* Called when a new connection for this protocol found. */
  90 static int udp_new(struct nf_conn *conntrack, const struct sk_buff *skb,
  91                    unsigned int dataoff)
  92 {
  93         return 1;
  94 }
  95
  96 static int udp_error(struct sk_buff *skb, unsigned int dataoff,
  97                      enum ip_conntrack_info *ctinfo,
  98                      int pf,
  99                      unsigned int hooknum)
 100 {
 101         unsigned int udplen = skb->len - dataoff;
 102         struct udphdr _hdr, *hdr;
 103
 104         /* Header is too small? */
 105         hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
 106         if (hdr == NULL) {
 107                 if (LOG_INVALID(IPPROTO_UDP))
 108                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 109                                       "nf_ct_udp: short packet ");
 110                 return -NF_ACCEPT;
 111         }
 112
 113         /* Truncated/malformed packets */
 114         if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) {
 115                 if (LOG_INVALID(IPPROTO_UDP))
 116                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 117                                 "nf_ct_udp: truncated/malformed packet ");
 118                 return -NF_ACCEPT;
 119         }
 120
 121 #if defined(CONFIG_BCM_NAT) || defined(CONFIG_BCM_NAT_MODULE)
 122         if (ipv4_conntrack_fastnat)
 123                 return NF_ACCEPT;
 124 #endif
 125
 126         /* Packet with no checksum */
 127         if (!hdr->check)
 128                 return NF_ACCEPT;
 129
 130         /* Checksum invalid? Ignore.
 131          * We skip checking packets on the outgoing path
 132          * because the checksum is assumed to be correct.
 133          * FIXME: Source route IP option packets --RR */
 134         if (nf_conntrack_checksum &&
 135             ((pf == PF_INET && hooknum == NF_IP_PRE_ROUTING) ||
 136              (pf == PF_INET6 && hooknum == NF_IP6_PRE_ROUTING)) &&
 137             nf_checksum(skb, hooknum, dataoff, IPPROTO_UDP, pf)) {
 138                 if (LOG_INVALID(IPPROTO_UDP))
 139                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 140                                 "nf_ct_udp: bad UDP checksum ");
 141                 return -NF_ACCEPT;
 142         }
 143
 144         return NF_ACCEPT;
 145 }
 146
 147 #ifdef CONFIG_SYSCTL
 148 static unsigned int udp_sysctl_table_users;
 149 static struct ctl_table_header *udp_sysctl_header;
 150 static struct ctl_table udp_sysctl_table[] = {
 151         {
 152                 .ctl_name       = NET_NF_CONNTRACK_UDP_TIMEOUT,
 153                 .procname       = "nf_conntrack_udp_timeout",
 154                 .data           = &nf_ct_udp_timeout,
 155                 .maxlen         = sizeof(unsigned int),
 156                 .mode           = 0644,
 157                 .proc_handler   = &proc_dointvec_jiffies,
 158         },
 159         {
 160                 .ctl_name       = NET_NF_CONNTRACK_UDP_TIMEOUT_STREAM,
 161                 .procname       = "nf_conntrack_udp_timeout_stream",
 162                 .data           = &nf_ct_udp_timeout_stream,
 163                 .maxlen         = sizeof(unsigned int),
 164                 .mode           = 0644,
 165                 .proc_handler   = &proc_dointvec_jiffies,
 166         },
 167         {
 168                 .ctl_name       = 0
 169         }
 170 };
 171 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
 172 static struct ctl_table udp_compat_sysctl_table[] = {
 173         {
 174                 .ctl_name       = NET_IPV4_NF_CONNTRACK_UDP_TIMEOUT,
 175                 .procname       = "ip_conntrack_udp_timeout",
 176                 .data           = &nf_ct_udp_timeout,
 177                 .maxlen         = sizeof(unsigned int),
 178                 .mode           = 0644,
 179                 .proc_handler   = &proc_dointvec_jiffies,
 180         },
 181         {
 182                 .ctl_name       = NET_IPV4_NF_CONNTRACK_UDP_TIMEOUT_STREAM,
 183                 .procname       = "ip_conntrack_udp_timeout_stream",
 184                 .data           = &nf_ct_udp_timeout_stream,
 185                 .maxlen         = sizeof(unsigned int),
 186                 .mode           = 0644,
 187                 .proc_handler   = &proc_dointvec_jiffies,
 188         },
 189         {
 190                 .ctl_name       = 0
 191         }
 192 };
 193 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
 194 #endif /* CONFIG_SYSCTL */
 195
 196 struct nf_conntrack_l4proto nf_conntrack_l4proto_udp4 =
 197 {
 198         .l3proto                = PF_INET,
 199         .l4proto                = IPPROTO_UDP,
 200         .name                   = "udp",
 201         .pkt_to_tuple           = udp_pkt_to_tuple,
 202         .invert_tuple           = udp_invert_tuple,
 203         .print_tuple            = udp_print_tuple,
 204         .packet                 = udp_packet,
 205         .new                    = udp_new,
 206         .error                  = udp_error,
 207 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 208         .tuple_to_nfattr        = nf_ct_port_tuple_to_nfattr,
 209         .nfattr_to_tuple        = nf_ct_port_nfattr_to_tuple,
 210 #endif
 211 #ifdef CONFIG_SYSCTL
 212         .ctl_table_users        = &udp_sysctl_table_users,
 213         .ctl_table_header       = &udp_sysctl_header,
 214         .ctl_table              = udp_sysctl_table,
 215 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
 216         .ctl_compat_table       = udp_compat_sysctl_table,
 217 #endif
 218 #endif
 219 };
 220 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp4);
 221
 222 struct nf_conntrack_l4proto nf_conntrack_l4proto_udp6 =
 223 {
 224         .l3proto                = PF_INET6,
 225         .l4proto                = IPPROTO_UDP,
 226         .name                   = "udp",
 227         .pkt_to_tuple           = udp_pkt_to_tuple,
 228         .invert_tuple           = udp_invert_tuple,
 229         .print_tuple            = udp_print_tuple,
 230         .packet                 = udp_packet,
 231         .new                    = udp_new,
 232         .error                  = udp_error,
 233 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 234         .tuple_to_nfattr        = nf_ct_port_tuple_to_nfattr,
 235         .nfattr_to_tuple        = nf_ct_port_nfattr_to_tuple,
 236 #endif
 237 #ifdef CONFIG_SYSCTL
 238         .ctl_table_users        = &udp_sysctl_table_users,
 239         .ctl_table_header       = &udp_sysctl_header,
 240         .ctl_table              = udp_sysctl_table,
 241 #endif
 242 };
 243 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp6);