Pull sem2mutex-ioc4 into release branch

[deliverable/linux.git] / net / ipv4 / netfilter / nf_conntrack_l3proto_ipv4.c

/* (C) 1999-2001 Paul `Rusty' Russell
 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
 *      - move L3 protocol dependent part to this file.
 * 23 Mar 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
 *      - add get_features() to support various size of conntrack
 *        structures.
 *
 * Derived from net/ipv4/netfilter/ip_conntrack_standalone.c
 */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/ip.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/icmp.h>
#include <linux/sysctl.h>
#include <net/route.h>
#include <net/ip.h>

#include <linux/netfilter_ipv4.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_protocol.h>
#include <net/netfilter/nf_conntrack_l3proto.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>

#if 0
#define DEBUGP printk
#else
#define DEBUGP(format, args...)
#endif

DECLARE_PER_CPU(struct nf_conntrack_stat, nf_conntrack_stat);

static int ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
                             struct nf_conntrack_tuple *tuple)
{
        u_int32_t _addrs[2], *ap;
        ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
                                sizeof(u_int32_t) * 2, _addrs);
        if (ap == NULL)
                return 0;

        tuple->src.u3.ip = ap[0];
        tuple->dst.u3.ip = ap[1];

        return 1;
}

static int ipv4_invert_tuple(struct nf_conntrack_tuple *tuple,
                           const struct nf_conntrack_tuple *orig)
{
        tuple->src.u3.ip = orig->dst.u3.ip;
        tuple->dst.u3.ip = orig->src.u3.ip;

        return 1;
}

static int ipv4_print_tuple(struct seq_file *s,
                            const struct nf_conntrack_tuple *tuple)
{
        return seq_printf(s, "src=%u.%u.%u.%u dst=%u.%u.%u.%u ",
                          NIPQUAD(tuple->src.u3.ip),
                          NIPQUAD(tuple->dst.u3.ip));
}

static int ipv4_print_conntrack(struct seq_file *s,
                                const struct nf_conn *conntrack)
{
        return 0;
}

/* Returns new sk_buff, or NULL */
static struct sk_buff *
nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
{
        skb_orphan(skb);

        local_bh_disable();
        skb = ip_defrag(skb, user);
        local_bh_enable();

        if (skb)
                ip_send_check(skb->nh.iph);

        return skb;
}

static int
ipv4_prepare(struct sk_buff **pskb, unsigned int hooknum, unsigned int *dataoff,
             u_int8_t *protonum)
{
        /* Never happen */
        if ((*pskb)->nh.iph->frag_off & htons(IP_OFFSET)) {
                if (net_ratelimit()) {
                        printk(KERN_ERR "ipv4_prepare: Frag of proto %u (hook=%u)\n",
                        (*pskb)->nh.iph->protocol, hooknum);
                }
                return -NF_DROP;
        }

        *dataoff = (*pskb)->nh.raw - (*pskb)->data + (*pskb)->nh.iph->ihl*4;
        *protonum = (*pskb)->nh.iph->protocol;

        return NF_ACCEPT;
}

int nat_module_is_loaded = 0;
static u_int32_t ipv4_get_features(const struct nf_conntrack_tuple *tuple)
{
        if (nat_module_is_loaded)
                return NF_CT_F_NAT;

        return NF_CT_F_BASIC;
}

static unsigned int ipv4_confirm(unsigned int hooknum,
                                 struct sk_buff **pskb,
                                 const struct net_device *in,
                                 const struct net_device *out,
                                 int (*okfn)(struct sk_buff *))
{
        /* We've seen it coming out the other side: confirm it */
        return nf_conntrack_confirm(pskb);
}

static unsigned int ipv4_conntrack_help(unsigned int hooknum,
                                      struct sk_buff **pskb,
                                      const struct net_device *in,
                                      const struct net_device *out,
                                      int (*okfn)(struct sk_buff *))
{
        struct nf_conn *ct;
        enum ip_conntrack_info ctinfo;

        /* This is where we call the helper: as the packet goes out. */
        ct = nf_ct_get(*pskb, &ctinfo);
        if (ct && ct->helper) {
                unsigned int ret;
                ret = ct->helper->help(pskb,
                                       (*pskb)->nh.raw - (*pskb)->data
                                                       + (*pskb)->nh.iph->ihl*4,
                                       ct, ctinfo);
                if (ret != NF_ACCEPT)
                        return ret;
        }
        return NF_ACCEPT;
}

static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
                                          struct sk_buff **pskb,
                                          const struct net_device *in,
                                          const struct net_device *out,
                                          int (*okfn)(struct sk_buff *))
{
#if !defined(CONFIG_IP_NF_NAT) && !defined(CONFIG_IP_NF_NAT_MODULE)
        /* Previously seen (loopback)?  Ignore.  Do this before
           fragment check. */
        if ((*pskb)->nfct)
                return NF_ACCEPT;
#endif

        /* Gather fragments. */
        if ((*pskb)->nh.iph->frag_off & htons(IP_MF|IP_OFFSET)) {
                *pskb = nf_ct_ipv4_gather_frags(*pskb,
                                                hooknum == NF_IP_PRE_ROUTING ?
                                                IP_DEFRAG_CONNTRACK_IN :
                                                IP_DEFRAG_CONNTRACK_OUT);
                if (!*pskb)
                        return NF_STOLEN;
        }
        return NF_ACCEPT;
}

static unsigned int ipv4_conntrack_in(unsigned int hooknum,
                                      struct sk_buff **pskb,
                                      const struct net_device *in,
                                      const struct net_device *out,
                                      int (*okfn)(struct sk_buff *))
{
        return nf_conntrack_in(PF_INET, hooknum, pskb);
}

static unsigned int ipv4_conntrack_local(unsigned int hooknum,
                                         struct sk_buff **pskb,
                                         const struct net_device *in,
                                         const struct net_device *out,
                                         int (*okfn)(struct sk_buff *))
{
        /* root is playing with raw sockets. */
        if ((*pskb)->len < sizeof(struct iphdr)
            || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr)) {
                if (net_ratelimit())
                        printk("ipt_hook: happy cracking.\n");
                return NF_ACCEPT;
        }
        return nf_conntrack_in(PF_INET, hooknum, pskb);
}

/* Connection tracking may drop packets, but never alters them, so
   make it the first hook. */
static struct nf_hook_ops ipv4_conntrack_defrag_ops = {
        .hook           = ipv4_conntrack_defrag,
        .owner          = THIS_MODULE,
        .pf             = PF_INET,
        .hooknum        = NF_IP_PRE_ROUTING,
        .priority       = NF_IP_PRI_CONNTRACK_DEFRAG,
};

static struct nf_hook_ops ipv4_conntrack_in_ops = {
        .hook           = ipv4_conntrack_in,
        .owner          = THIS_MODULE,
        .pf             = PF_INET,
        .hooknum        = NF_IP_PRE_ROUTING,
        .priority       = NF_IP_PRI_CONNTRACK,
};

static struct nf_hook_ops ipv4_conntrack_defrag_local_out_ops = {
        .hook           = ipv4_conntrack_defrag,
        .owner          = THIS_MODULE,
        .pf             = PF_INET,
        .hooknum        = NF_IP_LOCAL_OUT,
        .priority       = NF_IP_PRI_CONNTRACK_DEFRAG,
};

static struct nf_hook_ops ipv4_conntrack_local_out_ops = {
        .hook           = ipv4_conntrack_local,
        .owner          = THIS_MODULE,
        .pf             = PF_INET,
        .hooknum        = NF_IP_LOCAL_OUT,
        .priority       = NF_IP_PRI_CONNTRACK,
};

/* helpers */
static struct nf_hook_ops ipv4_conntrack_helper_out_ops = {
        .hook           = ipv4_conntrack_help,
        .owner          = THIS_MODULE,
        .pf             = PF_INET,
        .hooknum        = NF_IP_POST_ROUTING,
        .priority       = NF_IP_PRI_CONNTRACK_HELPER,
};

static struct nf_hook_ops ipv4_conntrack_helper_in_ops = {
        .hook           = ipv4_conntrack_help,
        .owner          = THIS_MODULE,
        .pf             = PF_INET,
        .hooknum        = NF_IP_LOCAL_IN,
        .priority       = NF_IP_PRI_CONNTRACK_HELPER,
};


/* Refragmenter; last chance. */
static struct nf_hook_ops ipv4_conntrack_out_ops = {
        .hook           = ipv4_confirm,
        .owner          = THIS_MODULE,
        .pf             = PF_INET,
        .hooknum        = NF_IP_POST_ROUTING,
        .priority       = NF_IP_PRI_CONNTRACK_CONFIRM,
};

static struct nf_hook_ops ipv4_conntrack_local_in_ops = {
        .hook           = ipv4_confirm,
        .owner          = THIS_MODULE,
        .pf             = PF_INET,
        .hooknum        = NF_IP_LOCAL_IN,
        .priority       = NF_IP_PRI_CONNTRACK_CONFIRM,
};

#ifdef CONFIG_SYSCTL
/* From nf_conntrack_proto_icmp.c */
extern unsigned int nf_ct_icmp_timeout;
static struct ctl_table_header *nf_ct_ipv4_sysctl_header;

static ctl_table nf_ct_sysctl_table[] = {
        {
                .ctl_name       = NET_NF_CONNTRACK_ICMP_TIMEOUT,
                .procname       = "nf_conntrack_icmp_timeout",
                .data           = &nf_ct_icmp_timeout,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_jiffies,
        },
        { .ctl_name = 0 }
};

static ctl_table nf_ct_netfilter_table[] = {
        {
                .ctl_name       = NET_NETFILTER,
                .procname       = "netfilter",
                .mode           = 0555,
                .child          = nf_ct_sysctl_table,
        },
        { .ctl_name = 0 }
};

static ctl_table nf_ct_net_table[] = {
        {
                .ctl_name       = CTL_NET,
                .procname       = "net",
                .mode           = 0555,
                .child          = nf_ct_netfilter_table,
        },
        { .ctl_name = 0 }
};
#endif

/* Fast function for those who don't want to parse /proc (and I don't
   blame them). */
/* Reversing the socket's dst/src point of view gives us the reply
   mapping. */
static int
getorigdst(struct sock *sk, int optval, void __user *user, int *len)
{
        struct inet_sock *inet = inet_sk(sk);
        struct nf_conntrack_tuple_hash *h;
        struct nf_conntrack_tuple tuple;
        
        NF_CT_TUPLE_U_BLANK(&tuple);
        tuple.src.u3.ip = inet->rcv_saddr;
        tuple.src.u.tcp.port = inet->sport;
        tuple.dst.u3.ip = inet->daddr;
        tuple.dst.u.tcp.port = inet->dport;
        tuple.src.l3num = PF_INET;
        tuple.dst.protonum = IPPROTO_TCP;

        /* We only do TCP at the moment: is there a better way? */
        if (strcmp(sk->sk_prot->name, "TCP")) {
                DEBUGP("SO_ORIGINAL_DST: Not a TCP socket\n");
                return -ENOPROTOOPT;
        }

        if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
                DEBUGP("SO_ORIGINAL_DST: len %u not %u\n",
                       *len, sizeof(struct sockaddr_in));
                return -EINVAL;
        }

        h = nf_conntrack_find_get(&tuple, NULL);
        if (h) {
                struct sockaddr_in sin;
                struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);

                sin.sin_family = AF_INET;
                sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
                        .tuple.dst.u.tcp.port;
                sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
                        .tuple.dst.u3.ip;

                DEBUGP("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
                       NIPQUAD(sin.sin_addr.s_addr), ntohs(sin.sin_port));
                nf_ct_put(ct);
                if (copy_to_user(user, &sin, sizeof(sin)) != 0)
                        return -EFAULT;
                else
                        return 0;
        }
        DEBUGP("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
               NIPQUAD(tuple.src.u3.ip), ntohs(tuple.src.u.tcp.port),
               NIPQUAD(tuple.dst.u3.ip), ntohs(tuple.dst.u.tcp.port));
        return -ENOENT;
}

#if defined(CONFIG_NF_CT_NETLINK) || \
    defined(CONFIG_NF_CT_NETLINK_MODULE)

#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_conntrack.h>

static int ipv4_tuple_to_nfattr(struct sk_buff *skb,
                                const struct nf_conntrack_tuple *tuple)
{
        NFA_PUT(skb, CTA_IP_V4_SRC, sizeof(u_int32_t),
                &tuple->src.u3.ip);
        NFA_PUT(skb, CTA_IP_V4_DST, sizeof(u_int32_t),
                &tuple->dst.u3.ip);
        return 0;

nfattr_failure:
        return -1;
}

static const size_t cta_min_ip[CTA_IP_MAX] = {
        [CTA_IP_V4_SRC-1]       = sizeof(u_int32_t),
        [CTA_IP_V4_DST-1]       = sizeof(u_int32_t),
};

static int ipv4_nfattr_to_tuple(struct nfattr *tb[],
                                struct nf_conntrack_tuple *t)
{
        if (!tb[CTA_IP_V4_SRC-1] || !tb[CTA_IP_V4_DST-1])
                return -EINVAL;

        if (nfattr_bad_size(tb, CTA_IP_MAX, cta_min_ip))
                return -EINVAL;

        t->src.u3.ip =
                *(u_int32_t *)NFA_DATA(tb[CTA_IP_V4_SRC-1]);
        t->dst.u3.ip =
                *(u_int32_t *)NFA_DATA(tb[CTA_IP_V4_DST-1]);

        return 0;
}
#endif

static struct nf_sockopt_ops so_getorigdst = {
        .pf             = PF_INET,
        .get_optmin     = SO_ORIGINAL_DST,
        .get_optmax     = SO_ORIGINAL_DST+1,
        .get            = &getorigdst,
};

struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 = {
        .l3proto         = PF_INET,
        .name            = "ipv4",
        .pkt_to_tuple    = ipv4_pkt_to_tuple,
        .invert_tuple    = ipv4_invert_tuple,
        .print_tuple     = ipv4_print_tuple,
        .print_conntrack = ipv4_print_conntrack,
        .prepare         = ipv4_prepare,
        .get_features    = ipv4_get_features,
#if defined(CONFIG_NF_CT_NETLINK) || \
    defined(CONFIG_NF_CT_NETLINK_MODULE)
        .tuple_to_nfattr = ipv4_tuple_to_nfattr,
        .nfattr_to_tuple = ipv4_nfattr_to_tuple,
#endif
        .me              = THIS_MODULE,
};

extern struct nf_conntrack_protocol nf_conntrack_protocol_tcp4;
extern struct nf_conntrack_protocol nf_conntrack_protocol_udp4;
extern struct nf_conntrack_protocol nf_conntrack_protocol_icmp;
static int init_or_cleanup(int init)
{
        int ret = 0;

        if (!init) goto cleanup;

        ret = nf_register_sockopt(&so_getorigdst);
        if (ret < 0) {
                printk(KERN_ERR "Unable to register netfilter socket option\n");
                goto cleanup_nothing;
        }

        ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_tcp4);
        if (ret < 0) {
                printk("nf_conntrack_ipv4: can't register tcp.\n");
                goto cleanup_sockopt;
        }

        ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_udp4);
        if (ret < 0) {
                printk("nf_conntrack_ipv4: can't register udp.\n");
                goto cleanup_tcp;
        }

        ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_icmp);
        if (ret < 0) {
                printk("nf_conntrack_ipv4: can't register icmp.\n");
                goto cleanup_udp;
        }

        ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4);
        if (ret < 0) {
                printk("nf_conntrack_ipv4: can't register ipv4\n");
                goto cleanup_icmp;
        }

        ret = nf_register_hook(&ipv4_conntrack_defrag_ops);
        if (ret < 0) {
                printk("nf_conntrack_ipv4: can't register pre-routing defrag hook.\n");
                goto cleanup_ipv4;
        }
        ret = nf_register_hook(&ipv4_conntrack_defrag_local_out_ops);
        if (ret < 0) {
                printk("nf_conntrack_ipv4: can't register local_out defrag hook.\n");
                goto cleanup_defragops;
        }

        ret = nf_register_hook(&ipv4_conntrack_in_ops);
        if (ret < 0) {
                printk("nf_conntrack_ipv4: can't register pre-routing hook.\n");
                goto cleanup_defraglocalops;
        }

        ret = nf_register_hook(&ipv4_conntrack_local_out_ops);
        if (ret < 0) {
                printk("nf_conntrack_ipv4: can't register local out hook.\n");
                goto cleanup_inops;
        }

        ret = nf_register_hook(&ipv4_conntrack_helper_in_ops);
        if (ret < 0) {
                printk("nf_conntrack_ipv4: can't register local helper hook.\n");
                goto cleanup_inandlocalops;
        }

        ret = nf_register_hook(&ipv4_conntrack_helper_out_ops);
        if (ret < 0) {
                printk("nf_conntrack_ipv4: can't register postrouting helper hook.\n");
                goto cleanup_helperinops;
        }

        ret = nf_register_hook(&ipv4_conntrack_out_ops);
        if (ret < 0) {
                printk("nf_conntrack_ipv4: can't register post-routing hook.\n");
                goto cleanup_helperoutops;
        }

        ret = nf_register_hook(&ipv4_conntrack_local_in_ops);
        if (ret < 0) {
                printk("nf_conntrack_ipv4: can't register local in hook.\n");
                goto cleanup_inoutandlocalops;
        }

#ifdef CONFIG_SYSCTL
        nf_ct_ipv4_sysctl_header = register_sysctl_table(nf_ct_net_table, 0);
        if (nf_ct_ipv4_sysctl_header == NULL) {
                printk("nf_conntrack: can't register to sysctl.\n");
                ret = -ENOMEM;
                goto cleanup_localinops;
        }
#endif
        return ret;

 cleanup:
        synchronize_net();
#ifdef CONFIG_SYSCTL
        unregister_sysctl_table(nf_ct_ipv4_sysctl_header);
 cleanup_localinops:
#endif
        nf_unregister_hook(&ipv4_conntrack_local_in_ops);
 cleanup_inoutandlocalops:
        nf_unregister_hook(&ipv4_conntrack_out_ops);
 cleanup_helperoutops:
        nf_unregister_hook(&ipv4_conntrack_helper_out_ops);
 cleanup_helperinops:
        nf_unregister_hook(&ipv4_conntrack_helper_in_ops);
 cleanup_inandlocalops:
        nf_unregister_hook(&ipv4_conntrack_local_out_ops);
 cleanup_inops:
        nf_unregister_hook(&ipv4_conntrack_in_ops);
 cleanup_defraglocalops:
        nf_unregister_hook(&ipv4_conntrack_defrag_local_out_ops);
 cleanup_defragops:
        nf_unregister_hook(&ipv4_conntrack_defrag_ops);
 cleanup_ipv4:
        nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
 cleanup_icmp:
        nf_conntrack_protocol_unregister(&nf_conntrack_protocol_icmp);
 cleanup_udp:
        nf_conntrack_protocol_unregister(&nf_conntrack_protocol_udp4);
 cleanup_tcp:
        nf_conntrack_protocol_unregister(&nf_conntrack_protocol_tcp4);
 cleanup_sockopt:
        nf_unregister_sockopt(&so_getorigdst);
 cleanup_nothing:
        return ret;
}

MODULE_LICENSE("GPL");

static int __init init(void)
{
        need_conntrack();
        return init_or_cleanup(1);
}

static void __exit fini(void)
{
        init_or_cleanup(0);
}

module_init(init);
module_exit(fini);

EXPORT_SYMBOL(nf_ct_ipv4_gather_frags);