projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* Kernel module to match connection tracking information. |
| 2 | * Superset of Rusty's minimalistic state match. | |
| 3 | * | |
| 4 | * (C) 2001 Marc Boucher (marc@mbsi.ca). | |
| 5 | * | |
| 6 | * This program is free software; you can redistribute it and/or modify | |
| 7 | * it under the terms of the GNU General Public License version 2 as | |
| 8 | * published by the Free Software Foundation. | |
| 9 | */ | |
| 10 | ||
| 11 | #include <linux/module.h> | |
| 12 | #include <linux/skbuff.h> | |
| 13 | #include <linux/netfilter_ipv4/ip_conntrack.h> | |
| 14 | #include <linux/netfilter_ipv4/ip_tables.h> | |
| 15 | #include <linux/netfilter_ipv4/ipt_conntrack.h> | |
| 16 | ||
| 17 | MODULE_LICENSE("GPL"); | |
| 18 | MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>"); | |
| 19 | MODULE_DESCRIPTION("iptables connection tracking match module"); | |
| 20 | ||
| 21 | static int | |
| 22 | match(const struct sk_buff *skb, | |
| 23 | const struct net_device *in, | |
| 24 | const struct net_device *out, | |
| 25 | const void *matchinfo, | |
| 26 | int offset, | |
| 27 | int *hotdrop) | |
| 28 | { | |
| 29 | const struct ipt_conntrack_info *sinfo = matchinfo; | |
| 30 | struct ip_conntrack *ct; | |
| 31 | enum ip_conntrack_info ctinfo; | |
| 32 | unsigned int statebit; | |
| 33 | ||
| 34 | ct = ip_conntrack_get((struct sk_buff *)skb, &ctinfo); | |
| 35 | ||
| 36 | #define FWINV(bool,invflg) ((bool) ^ !!(sinfo->invflags & invflg)) | |
| 37 | ||
| 38 | if (ct == &ip_conntrack_untracked) | |
| 39 | statebit = IPT_CONNTRACK_STATE_UNTRACKED; | |
| 40 | else if (ct) | |
| 41 | statebit = IPT_CONNTRACK_STATE_BIT(ctinfo); | |
| 42 | else | |
| 43 | statebit = IPT_CONNTRACK_STATE_INVALID; | |
| 44 | ||
| 45 | if(sinfo->flags & IPT_CONNTRACK_STATE) { | |
| 46 | if (ct) { | |
| 47 | if(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip != | |
| 48 | ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip) | |
| 49 | statebit |= IPT_CONNTRACK_STATE_SNAT; | |
| 50 | ||
| 51 | if(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip != | |
| 52 | ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip) | |
| 53 | statebit |= IPT_CONNTRACK_STATE_DNAT; | |
| 54 | } | |
| 55 | ||
| 56 | if (FWINV((statebit & sinfo->statemask) == 0, IPT_CONNTRACK_STATE)) | |
| 57 | return 0; | |
| 58 | } | |
| 59 | ||
| 60 | if(sinfo->flags & IPT_CONNTRACK_PROTO) { | |
| 61 | if (!ct || FWINV(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum != sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.protonum, IPT_CONNTRACK_PROTO)) | |
| 62 | return 0; | |
| 63 | } | |
| 64 | ||
| 65 | if(sinfo->flags & IPT_CONNTRACK_ORIGSRC) { | |
| 66 | if (!ct || FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip&sinfo->sipmsk[IP_CT_DIR_ORIGINAL].s_addr) != sinfo->tuple[IP_CT_DIR_ORIGINAL].src.ip, IPT_CONNTRACK_ORIGSRC)) | |
| 67 | return 0; | |
| 68 | } | |
| 69 | ||
| 70 | if(sinfo->flags & IPT_CONNTRACK_ORIGDST) { | |
| 71 | if (!ct || FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip&sinfo->dipmsk[IP_CT_DIR_ORIGINAL].s_addr) != sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.ip, IPT_CONNTRACK_ORIGDST)) | |
| 72 | return 0; | |
| 73 | } | |
| 74 | ||
| 75 | if(sinfo->flags & IPT_CONNTRACK_REPLSRC) { | |
| 76 | if (!ct || FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip&sinfo->sipmsk[IP_CT_DIR_REPLY].s_addr) != sinfo->tuple[IP_CT_DIR_REPLY].src.ip, IPT_CONNTRACK_REPLSRC)) | |
| 77 | return 0; | |
| 78 | } | |
| 79 | ||
| 80 | if(sinfo->flags & IPT_CONNTRACK_REPLDST) { | |
| 81 | if (!ct || FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip&sinfo->dipmsk[IP_CT_DIR_REPLY].s_addr) != sinfo->tuple[IP_CT_DIR_REPLY].dst.ip, IPT_CONNTRACK_REPLDST)) | |
| 82 | return 0; | |
| 83 | } | |
| 84 | ||
| 85 | if(sinfo->flags & IPT_CONNTRACK_STATUS) { | |
| 86 | if (!ct || FWINV((ct->status & sinfo->statusmask) == 0, IPT_CONNTRACK_STATUS)) | |
| 87 | return 0; | |
| 88 | } | |
| 89 | ||
| 90 | if(sinfo->flags & IPT_CONNTRACK_EXPIRES) { | |
| 91 | unsigned long expires; | |
| 92 | ||
| 93 | if(!ct) | |
| 94 | return 0; | |
| 95 | ||
| 96 | expires = timer_pending(&ct->timeout) ? (ct->timeout.expires - jiffies)/HZ : 0; | |
| 97 | ||
| 98 | if (FWINV(!(expires >= sinfo->expires_min && expires <= sinfo->expires_max), IPT_CONNTRACK_EXPIRES)) | |
| 99 | return 0; | |
| 100 | } | |
| 101 | ||
| 102 | return 1; | |
| 103 | } | |
| 104 | ||
| 105 | static int check(const char *tablename, | |
| 106 | const struct ipt_ip *ip, | |
| 107 | void *matchinfo, | |
| 108 | unsigned int matchsize, | |
| 109 | unsigned int hook_mask) | |
| 110 | { | |
| 111 | if (matchsize != IPT_ALIGN(sizeof(struct ipt_conntrack_info))) | |
| 112 | return 0; | |
| 113 | ||
| 114 | return 1; | |
| 115 | } | |
| 116 | ||
| 117 | static struct ipt_match conntrack_match = { | |
| 118 | .name = "conntrack", | |
| 119 | .match = &match, | |
| 120 | .checkentry = &check, | |
| 121 | .me = THIS_MODULE, | |
| 122 | }; | |
| 123 | ||
| 124 | static int __init init(void) | |
| 125 | { | |
| 126 | need_ip_conntrack(); | |
| 127 | return ipt_register_match(&conntrack_match); | |
| 128 | } | |
| 129 | ||
| 130 | static void __exit fini(void) | |
| 131 | { | |
| 132 | ipt_unregister_match(&conntrack_match); | |
| 133 | } | |
| 134 | ||
| 135 | module_init(init); | |
| 136 | module_exit(fini); |