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![Jan Engelhardt](/assets/img/avatar_default.png)
Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
508 lines
13 KiB
C
508 lines
13 KiB
C
/* (C) 1999-2001 Paul `Rusty' Russell
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* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/types.h>
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#include <linux/ip.h>
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#include <linux/netfilter.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/icmp.h>
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#include <linux/sysctl.h>
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#include <net/route.h>
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#include <net/ip.h>
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#include <linux/netfilter_ipv4.h>
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#include <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_conntrack_helper.h>
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#include <net/netfilter/nf_conntrack_l4proto.h>
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#include <net/netfilter/nf_conntrack_l3proto.h>
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#include <net/netfilter/nf_conntrack_core.h>
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#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
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static int ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
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struct nf_conntrack_tuple *tuple)
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{
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const __be32 *ap;
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__be32 _addrs[2];
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ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
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sizeof(u_int32_t) * 2, _addrs);
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if (ap == NULL)
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return 0;
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tuple->src.u3.ip = ap[0];
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tuple->dst.u3.ip = ap[1];
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return 1;
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}
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static int ipv4_invert_tuple(struct nf_conntrack_tuple *tuple,
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const struct nf_conntrack_tuple *orig)
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{
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tuple->src.u3.ip = orig->dst.u3.ip;
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tuple->dst.u3.ip = orig->src.u3.ip;
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return 1;
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}
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static int ipv4_print_tuple(struct seq_file *s,
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const struct nf_conntrack_tuple *tuple)
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{
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return seq_printf(s, "src=%u.%u.%u.%u dst=%u.%u.%u.%u ",
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NIPQUAD(tuple->src.u3.ip),
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NIPQUAD(tuple->dst.u3.ip));
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}
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/* Returns new sk_buff, or NULL */
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static int nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
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{
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int err;
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skb_orphan(skb);
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local_bh_disable();
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err = ip_defrag(skb, user);
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local_bh_enable();
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if (!err)
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ip_send_check(ip_hdr(skb));
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return err;
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}
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static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
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unsigned int *dataoff, u_int8_t *protonum)
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{
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const struct iphdr *iph;
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struct iphdr _iph;
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iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
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if (iph == NULL)
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return -NF_DROP;
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/* Conntrack defragments packets, we might still see fragments
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* inside ICMP packets though. */
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if (iph->frag_off & htons(IP_OFFSET))
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return -NF_DROP;
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*dataoff = nhoff + (iph->ihl << 2);
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*protonum = iph->protocol;
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return NF_ACCEPT;
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}
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static unsigned int ipv4_confirm(unsigned int hooknum,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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/* We've seen it coming out the other side: confirm it */
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return nf_conntrack_confirm(skb);
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}
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static unsigned int ipv4_conntrack_help(unsigned int hooknum,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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struct nf_conn *ct;
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enum ip_conntrack_info ctinfo;
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const struct nf_conn_help *help;
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const struct nf_conntrack_helper *helper;
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/* This is where we call the helper: as the packet goes out. */
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ct = nf_ct_get(skb, &ctinfo);
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if (!ct || ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY)
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return NF_ACCEPT;
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help = nfct_help(ct);
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if (!help)
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return NF_ACCEPT;
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/* rcu_read_lock()ed by nf_hook_slow */
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helper = rcu_dereference(help->helper);
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if (!helper)
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return NF_ACCEPT;
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return helper->help(skb, skb_network_offset(skb) + ip_hdrlen(skb),
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ct, ctinfo);
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}
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static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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/* Previously seen (loopback)? Ignore. Do this before
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fragment check. */
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if (skb->nfct)
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return NF_ACCEPT;
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/* Gather fragments. */
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if (ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)) {
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if (nf_ct_ipv4_gather_frags(skb,
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hooknum == NF_INET_PRE_ROUTING ?
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IP_DEFRAG_CONNTRACK_IN :
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IP_DEFRAG_CONNTRACK_OUT))
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return NF_STOLEN;
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}
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return NF_ACCEPT;
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}
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static unsigned int ipv4_conntrack_in(unsigned int hooknum,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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return nf_conntrack_in(PF_INET, hooknum, skb);
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}
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static unsigned int ipv4_conntrack_local(unsigned int hooknum,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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/* root is playing with raw sockets. */
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if (skb->len < sizeof(struct iphdr) ||
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ip_hdrlen(skb) < sizeof(struct iphdr)) {
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if (net_ratelimit())
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printk("ipt_hook: happy cracking.\n");
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return NF_ACCEPT;
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}
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return nf_conntrack_in(PF_INET, hooknum, skb);
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}
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/* Connection tracking may drop packets, but never alters them, so
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make it the first hook. */
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static struct nf_hook_ops ipv4_conntrack_ops[] __read_mostly = {
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{
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.hook = ipv4_conntrack_defrag,
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.owner = THIS_MODULE,
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.pf = PF_INET,
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.hooknum = NF_INET_PRE_ROUTING,
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.priority = NF_IP_PRI_CONNTRACK_DEFRAG,
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},
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{
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.hook = ipv4_conntrack_in,
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.owner = THIS_MODULE,
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.pf = PF_INET,
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.hooknum = NF_INET_PRE_ROUTING,
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.priority = NF_IP_PRI_CONNTRACK,
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},
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{
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.hook = ipv4_conntrack_defrag,
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.owner = THIS_MODULE,
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.pf = PF_INET,
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.hooknum = NF_INET_LOCAL_OUT,
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.priority = NF_IP_PRI_CONNTRACK_DEFRAG,
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},
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{
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.hook = ipv4_conntrack_local,
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.owner = THIS_MODULE,
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.pf = PF_INET,
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.hooknum = NF_INET_LOCAL_OUT,
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.priority = NF_IP_PRI_CONNTRACK,
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},
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{
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.hook = ipv4_conntrack_help,
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.owner = THIS_MODULE,
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.pf = PF_INET,
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.hooknum = NF_INET_POST_ROUTING,
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.priority = NF_IP_PRI_CONNTRACK_HELPER,
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},
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{
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.hook = ipv4_conntrack_help,
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.owner = THIS_MODULE,
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.pf = PF_INET,
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.hooknum = NF_INET_LOCAL_IN,
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.priority = NF_IP_PRI_CONNTRACK_HELPER,
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},
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{
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.hook = ipv4_confirm,
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.owner = THIS_MODULE,
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.pf = PF_INET,
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.hooknum = NF_INET_POST_ROUTING,
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.priority = NF_IP_PRI_CONNTRACK_CONFIRM,
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},
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{
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.hook = ipv4_confirm,
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.owner = THIS_MODULE,
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.pf = PF_INET,
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.hooknum = NF_INET_LOCAL_IN,
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.priority = NF_IP_PRI_CONNTRACK_CONFIRM,
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},
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};
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#if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
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static int log_invalid_proto_min = 0;
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static int log_invalid_proto_max = 255;
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static ctl_table ip_ct_sysctl_table[] = {
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{
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.ctl_name = NET_IPV4_NF_CONNTRACK_MAX,
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.procname = "ip_conntrack_max",
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.data = &nf_conntrack_max,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = &proc_dointvec,
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},
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{
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.ctl_name = NET_IPV4_NF_CONNTRACK_COUNT,
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.procname = "ip_conntrack_count",
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.data = &nf_conntrack_count,
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.maxlen = sizeof(int),
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.mode = 0444,
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.proc_handler = &proc_dointvec,
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},
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{
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.ctl_name = NET_IPV4_NF_CONNTRACK_BUCKETS,
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.procname = "ip_conntrack_buckets",
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.data = &nf_conntrack_htable_size,
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.maxlen = sizeof(unsigned int),
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.mode = 0444,
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.proc_handler = &proc_dointvec,
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},
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{
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.ctl_name = NET_IPV4_NF_CONNTRACK_CHECKSUM,
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.procname = "ip_conntrack_checksum",
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.data = &nf_conntrack_checksum,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = &proc_dointvec,
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},
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{
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.ctl_name = NET_IPV4_NF_CONNTRACK_LOG_INVALID,
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.procname = "ip_conntrack_log_invalid",
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.data = &nf_ct_log_invalid,
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.maxlen = sizeof(unsigned int),
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.mode = 0644,
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.proc_handler = &proc_dointvec_minmax,
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.strategy = &sysctl_intvec,
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.extra1 = &log_invalid_proto_min,
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.extra2 = &log_invalid_proto_max,
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},
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{
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.ctl_name = 0
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}
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};
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#endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
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/* Fast function for those who don't want to parse /proc (and I don't
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blame them). */
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/* Reversing the socket's dst/src point of view gives us the reply
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mapping. */
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static int
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getorigdst(struct sock *sk, int optval, void __user *user, int *len)
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{
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const struct inet_sock *inet = inet_sk(sk);
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const struct nf_conntrack_tuple_hash *h;
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struct nf_conntrack_tuple tuple;
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NF_CT_TUPLE_U_BLANK(&tuple);
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tuple.src.u3.ip = inet->rcv_saddr;
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tuple.src.u.tcp.port = inet->sport;
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tuple.dst.u3.ip = inet->daddr;
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tuple.dst.u.tcp.port = inet->dport;
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tuple.src.l3num = PF_INET;
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tuple.dst.protonum = IPPROTO_TCP;
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/* We only do TCP at the moment: is there a better way? */
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if (strcmp(sk->sk_prot->name, "TCP")) {
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pr_debug("SO_ORIGINAL_DST: Not a TCP socket\n");
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return -ENOPROTOOPT;
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}
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if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
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pr_debug("SO_ORIGINAL_DST: len %d not %Zu\n",
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*len, sizeof(struct sockaddr_in));
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return -EINVAL;
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}
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h = nf_conntrack_find_get(&tuple);
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if (h) {
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struct sockaddr_in sin;
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struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
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sin.sin_family = AF_INET;
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sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
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.tuple.dst.u.tcp.port;
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sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
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.tuple.dst.u3.ip;
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memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
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pr_debug("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
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NIPQUAD(sin.sin_addr.s_addr), ntohs(sin.sin_port));
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nf_ct_put(ct);
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if (copy_to_user(user, &sin, sizeof(sin)) != 0)
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return -EFAULT;
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else
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return 0;
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}
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pr_debug("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
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NIPQUAD(tuple.src.u3.ip), ntohs(tuple.src.u.tcp.port),
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NIPQUAD(tuple.dst.u3.ip), ntohs(tuple.dst.u.tcp.port));
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return -ENOENT;
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}
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#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
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#include <linux/netfilter/nfnetlink.h>
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#include <linux/netfilter/nfnetlink_conntrack.h>
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static int ipv4_tuple_to_nlattr(struct sk_buff *skb,
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const struct nf_conntrack_tuple *tuple)
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{
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NLA_PUT_BE32(skb, CTA_IP_V4_SRC, tuple->src.u3.ip);
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NLA_PUT_BE32(skb, CTA_IP_V4_DST, tuple->dst.u3.ip);
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return 0;
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nla_put_failure:
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return -1;
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}
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static const struct nla_policy ipv4_nla_policy[CTA_IP_MAX+1] = {
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[CTA_IP_V4_SRC] = { .type = NLA_U32 },
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[CTA_IP_V4_DST] = { .type = NLA_U32 },
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};
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static int ipv4_nlattr_to_tuple(struct nlattr *tb[],
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struct nf_conntrack_tuple *t)
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{
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if (!tb[CTA_IP_V4_SRC] || !tb[CTA_IP_V4_DST])
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return -EINVAL;
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t->src.u3.ip = nla_get_be32(tb[CTA_IP_V4_SRC]);
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t->dst.u3.ip = nla_get_be32(tb[CTA_IP_V4_DST]);
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return 0;
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}
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#endif
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static struct nf_sockopt_ops so_getorigdst = {
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.pf = PF_INET,
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.get_optmin = SO_ORIGINAL_DST,
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.get_optmax = SO_ORIGINAL_DST+1,
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.get = &getorigdst,
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.owner = THIS_MODULE,
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};
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struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly = {
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.l3proto = PF_INET,
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.name = "ipv4",
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.pkt_to_tuple = ipv4_pkt_to_tuple,
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.invert_tuple = ipv4_invert_tuple,
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.print_tuple = ipv4_print_tuple,
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.get_l4proto = ipv4_get_l4proto,
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#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
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.tuple_to_nlattr = ipv4_tuple_to_nlattr,
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.nlattr_to_tuple = ipv4_nlattr_to_tuple,
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.nla_policy = ipv4_nla_policy,
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#endif
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#if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
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.ctl_table_path = nf_net_ipv4_netfilter_sysctl_path,
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.ctl_table = ip_ct_sysctl_table,
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#endif
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.me = THIS_MODULE,
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};
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module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
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&nf_conntrack_htable_size, 0600);
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MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
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MODULE_ALIAS("ip_conntrack");
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MODULE_LICENSE("GPL");
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static int __init nf_conntrack_l3proto_ipv4_init(void)
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{
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int ret = 0;
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need_conntrack();
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ret = nf_register_sockopt(&so_getorigdst);
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if (ret < 0) {
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printk(KERN_ERR "Unable to register netfilter socket option\n");
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return ret;
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}
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ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp4);
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if (ret < 0) {
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printk("nf_conntrack_ipv4: can't register tcp.\n");
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goto cleanup_sockopt;
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}
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ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp4);
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if (ret < 0) {
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printk("nf_conntrack_ipv4: can't register udp.\n");
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goto cleanup_tcp;
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}
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ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmp);
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if (ret < 0) {
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printk("nf_conntrack_ipv4: can't register icmp.\n");
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goto cleanup_udp;
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}
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ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4);
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if (ret < 0) {
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printk("nf_conntrack_ipv4: can't register ipv4\n");
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goto cleanup_icmp;
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}
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ret = nf_register_hooks(ipv4_conntrack_ops,
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ARRAY_SIZE(ipv4_conntrack_ops));
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if (ret < 0) {
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printk("nf_conntrack_ipv4: can't register hooks.\n");
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goto cleanup_ipv4;
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}
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#if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
|
|
ret = nf_conntrack_ipv4_compat_init();
|
|
if (ret < 0)
|
|
goto cleanup_hooks;
|
|
#endif
|
|
return ret;
|
|
#if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
|
|
cleanup_hooks:
|
|
nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
|
|
#endif
|
|
cleanup_ipv4:
|
|
nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
|
|
cleanup_icmp:
|
|
nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
|
|
cleanup_udp:
|
|
nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
|
|
cleanup_tcp:
|
|
nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
|
|
cleanup_sockopt:
|
|
nf_unregister_sockopt(&so_getorigdst);
|
|
return ret;
|
|
}
|
|
|
|
static void __exit nf_conntrack_l3proto_ipv4_fini(void)
|
|
{
|
|
synchronize_net();
|
|
#if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
|
|
nf_conntrack_ipv4_compat_fini();
|
|
#endif
|
|
nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
|
|
nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
|
|
nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
|
|
nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
|
|
nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
|
|
nf_unregister_sockopt(&so_getorigdst);
|
|
}
|
|
|
|
module_init(nf_conntrack_l3proto_ipv4_init);
|
|
module_exit(nf_conntrack_l3proto_ipv4_fini);
|
|
|
|
void need_ipv4_conntrack(void)
|
|
{
|
|
return;
|
|
}
|
|
EXPORT_SYMBOL_GPL(need_ipv4_conntrack);
|