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![Rob Gill](/assets/img/avatar_default.png)
The user tool modinfo is used to get information on kernel modules, including a description where it is available. This patch adds a brief MODULE_DESCRIPTION to netfilter kernel modules (descriptions taken from Kconfig file or code comments) Signed-off-by: Rob Gill <rrobgill@protonmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
121 lines
3 KiB
C
121 lines
3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2013 Patrick McHardy <kaber@trash.net>
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*/
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_SYNPROXY.h>
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#include <net/netfilter/nf_synproxy.h>
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static unsigned int
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synproxy_tg4(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct xt_synproxy_info *info = par->targinfo;
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struct net *net = xt_net(par);
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struct synproxy_net *snet = synproxy_pernet(net);
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struct synproxy_options opts = {};
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struct tcphdr *th, _th;
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if (nf_ip_checksum(skb, xt_hooknum(par), par->thoff, IPPROTO_TCP))
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return NF_DROP;
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th = skb_header_pointer(skb, par->thoff, sizeof(_th), &_th);
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if (th == NULL)
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return NF_DROP;
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if (!synproxy_parse_options(skb, par->thoff, th, &opts))
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return NF_DROP;
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if (th->syn && !(th->ack || th->fin || th->rst)) {
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/* Initial SYN from client */
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this_cpu_inc(snet->stats->syn_received);
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if (th->ece && th->cwr)
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opts.options |= XT_SYNPROXY_OPT_ECN;
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opts.options &= info->options;
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opts.mss_encode = opts.mss_option;
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opts.mss_option = info->mss;
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if (opts.options & XT_SYNPROXY_OPT_TIMESTAMP)
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synproxy_init_timestamp_cookie(info, &opts);
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else
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opts.options &= ~(XT_SYNPROXY_OPT_WSCALE |
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XT_SYNPROXY_OPT_SACK_PERM |
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XT_SYNPROXY_OPT_ECN);
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synproxy_send_client_synack(net, skb, th, &opts);
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consume_skb(skb);
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return NF_STOLEN;
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} else if (th->ack && !(th->fin || th->rst || th->syn)) {
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/* ACK from client */
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if (synproxy_recv_client_ack(net, skb, th, &opts, ntohl(th->seq))) {
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consume_skb(skb);
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return NF_STOLEN;
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} else {
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return NF_DROP;
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}
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}
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return XT_CONTINUE;
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}
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static int synproxy_tg4_check(const struct xt_tgchk_param *par)
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{
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struct synproxy_net *snet = synproxy_pernet(par->net);
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const struct ipt_entry *e = par->entryinfo;
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int err;
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if (e->ip.proto != IPPROTO_TCP ||
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e->ip.invflags & XT_INV_PROTO)
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return -EINVAL;
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err = nf_ct_netns_get(par->net, par->family);
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if (err)
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return err;
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err = nf_synproxy_ipv4_init(snet, par->net);
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if (err) {
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nf_ct_netns_put(par->net, par->family);
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return err;
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}
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return err;
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}
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static void synproxy_tg4_destroy(const struct xt_tgdtor_param *par)
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{
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struct synproxy_net *snet = synproxy_pernet(par->net);
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nf_synproxy_ipv4_fini(snet, par->net);
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nf_ct_netns_put(par->net, par->family);
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}
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static struct xt_target synproxy_tg4_reg __read_mostly = {
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.name = "SYNPROXY",
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.family = NFPROTO_IPV4,
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.hooks = (1 << NF_INET_LOCAL_IN) | (1 << NF_INET_FORWARD),
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.target = synproxy_tg4,
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.targetsize = sizeof(struct xt_synproxy_info),
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.checkentry = synproxy_tg4_check,
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.destroy = synproxy_tg4_destroy,
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.me = THIS_MODULE,
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};
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static int __init synproxy_tg4_init(void)
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{
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return xt_register_target(&synproxy_tg4_reg);
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}
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static void __exit synproxy_tg4_exit(void)
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{
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xt_unregister_target(&synproxy_tg4_reg);
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}
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module_init(synproxy_tg4_init);
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module_exit(synproxy_tg4_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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MODULE_DESCRIPTION("Intercept TCP connections and establish them using syncookies");
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