| 1 | /* Kernel module to match connection tracking byte counter. |
| 2 | * GPL (C) 2002 Martin Devera (devik@cdi.cz). |
| 3 | */ |
| 4 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 5 | #include <linux/module.h> |
| 6 | #include <linux/bitops.h> |
| 7 | #include <linux/skbuff.h> |
| 8 | #include <linux/math64.h> |
| 9 | #include <linux/netfilter/x_tables.h> |
| 10 | #include <linux/netfilter/xt_connbytes.h> |
| 11 | #include <net/netfilter/nf_conntrack.h> |
| 12 | #include <net/netfilter/nf_conntrack_acct.h> |
| 13 | |
| 14 | MODULE_LICENSE("GPL"); |
| 15 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); |
| 16 | MODULE_DESCRIPTION("Xtables: Number of packets/bytes per connection matching"); |
| 17 | MODULE_ALIAS("ipt_connbytes"); |
| 18 | MODULE_ALIAS("ip6t_connbytes"); |
| 19 | |
| 20 | static bool |
| 21 | connbytes_mt(const struct sk_buff *skb, struct xt_action_param *par) |
| 22 | { |
| 23 | const struct xt_connbytes_info *sinfo = par->matchinfo; |
| 24 | const struct nf_conn *ct; |
| 25 | enum ip_conntrack_info ctinfo; |
| 26 | u_int64_t what = 0; /* initialize to make gcc happy */ |
| 27 | u_int64_t bytes = 0; |
| 28 | u_int64_t pkts = 0; |
| 29 | const struct nf_conn_counter *counters; |
| 30 | |
| 31 | ct = nf_ct_get(skb, &ctinfo); |
| 32 | if (!ct) |
| 33 | return false; |
| 34 | |
| 35 | counters = nf_conn_acct_find(ct); |
| 36 | if (!counters) |
| 37 | return false; |
| 38 | |
| 39 | switch (sinfo->what) { |
| 40 | case XT_CONNBYTES_PKTS: |
| 41 | switch (sinfo->direction) { |
| 42 | case XT_CONNBYTES_DIR_ORIGINAL: |
| 43 | what = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].packets); |
| 44 | break; |
| 45 | case XT_CONNBYTES_DIR_REPLY: |
| 46 | what = atomic64_read(&counters[IP_CT_DIR_REPLY].packets); |
| 47 | break; |
| 48 | case XT_CONNBYTES_DIR_BOTH: |
| 49 | what = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].packets); |
| 50 | what += atomic64_read(&counters[IP_CT_DIR_REPLY].packets); |
| 51 | break; |
| 52 | } |
| 53 | break; |
| 54 | case XT_CONNBYTES_BYTES: |
| 55 | switch (sinfo->direction) { |
| 56 | case XT_CONNBYTES_DIR_ORIGINAL: |
| 57 | what = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].bytes); |
| 58 | break; |
| 59 | case XT_CONNBYTES_DIR_REPLY: |
| 60 | what = atomic64_read(&counters[IP_CT_DIR_REPLY].bytes); |
| 61 | break; |
| 62 | case XT_CONNBYTES_DIR_BOTH: |
| 63 | what = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].bytes); |
| 64 | what += atomic64_read(&counters[IP_CT_DIR_REPLY].bytes); |
| 65 | break; |
| 66 | } |
| 67 | break; |
| 68 | case XT_CONNBYTES_AVGPKT: |
| 69 | switch (sinfo->direction) { |
| 70 | case XT_CONNBYTES_DIR_ORIGINAL: |
| 71 | bytes = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].bytes); |
| 72 | pkts = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].packets); |
| 73 | break; |
| 74 | case XT_CONNBYTES_DIR_REPLY: |
| 75 | bytes = atomic64_read(&counters[IP_CT_DIR_REPLY].bytes); |
| 76 | pkts = atomic64_read(&counters[IP_CT_DIR_REPLY].packets); |
| 77 | break; |
| 78 | case XT_CONNBYTES_DIR_BOTH: |
| 79 | bytes = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].bytes) + |
| 80 | atomic64_read(&counters[IP_CT_DIR_REPLY].bytes); |
| 81 | pkts = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].packets) + |
| 82 | atomic64_read(&counters[IP_CT_DIR_REPLY].packets); |
| 83 | break; |
| 84 | } |
| 85 | if (pkts != 0) |
| 86 | what = div64_u64(bytes, pkts); |
| 87 | break; |
| 88 | } |
| 89 | |
| 90 | if (sinfo->count.to >= sinfo->count.from) |
| 91 | return what <= sinfo->count.to && what >= sinfo->count.from; |
| 92 | else /* inverted */ |
| 93 | return what < sinfo->count.to || what > sinfo->count.from; |
| 94 | } |
| 95 | |
| 96 | static int connbytes_mt_check(const struct xt_mtchk_param *par) |
| 97 | { |
| 98 | const struct xt_connbytes_info *sinfo = par->matchinfo; |
| 99 | int ret; |
| 100 | |
| 101 | if (sinfo->what != XT_CONNBYTES_PKTS && |
| 102 | sinfo->what != XT_CONNBYTES_BYTES && |
| 103 | sinfo->what != XT_CONNBYTES_AVGPKT) |
| 104 | return -EINVAL; |
| 105 | |
| 106 | if (sinfo->direction != XT_CONNBYTES_DIR_ORIGINAL && |
| 107 | sinfo->direction != XT_CONNBYTES_DIR_REPLY && |
| 108 | sinfo->direction != XT_CONNBYTES_DIR_BOTH) |
| 109 | return -EINVAL; |
| 110 | |
| 111 | ret = nf_ct_l3proto_try_module_get(par->family); |
| 112 | if (ret < 0) |
| 113 | pr_info("cannot load conntrack support for proto=%u\n", |
| 114 | par->family); |
| 115 | |
| 116 | /* |
| 117 | * This filter cannot function correctly unless connection tracking |
| 118 | * accounting is enabled, so complain in the hope that someone notices. |
| 119 | */ |
| 120 | if (!nf_ct_acct_enabled(par->net)) { |
| 121 | pr_warning("Forcing CT accounting to be enabled\n"); |
| 122 | nf_ct_set_acct(par->net, true); |
| 123 | } |
| 124 | |
| 125 | return ret; |
| 126 | } |
| 127 | |
| 128 | static void connbytes_mt_destroy(const struct xt_mtdtor_param *par) |
| 129 | { |
| 130 | nf_ct_l3proto_module_put(par->family); |
| 131 | } |
| 132 | |
| 133 | static struct xt_match connbytes_mt_reg __read_mostly = { |
| 134 | .name = "connbytes", |
| 135 | .revision = 0, |
| 136 | .family = NFPROTO_UNSPEC, |
| 137 | .checkentry = connbytes_mt_check, |
| 138 | .match = connbytes_mt, |
| 139 | .destroy = connbytes_mt_destroy, |
| 140 | .matchsize = sizeof(struct xt_connbytes_info), |
| 141 | .me = THIS_MODULE, |
| 142 | }; |
| 143 | |
| 144 | static int __init connbytes_mt_init(void) |
| 145 | { |
| 146 | return xt_register_match(&connbytes_mt_reg); |
| 147 | } |
| 148 | |
| 149 | static void __exit connbytes_mt_exit(void) |
| 150 | { |
| 151 | xt_unregister_match(&connbytes_mt_reg); |
| 152 | } |
| 153 | |
| 154 | module_init(connbytes_mt_init); |
| 155 | module_exit(connbytes_mt_exit); |