net: Convert uses of typedef ctl_table to struct ctl_table

[mirror_ubuntu-bionic-kernel.git] / net / ipv4 / netfilter / nf_conntrack_l3proto_ipv4.c

/* (C) 1999-2001 Paul `Rusty' Russell
 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
 *
 * 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.
 */

#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_l4proto.h>
#include <net/netfilter/nf_conntrack_l3proto.h>
#include <net/netfilter/nf_conntrack_zones.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
#include <net/netfilter/nf_nat_helper.h>
#include <net/netfilter/ipv4/nf_defrag_ipv4.h>
#include <net/netfilter/nf_log.h>

static bool ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
                              struct nf_conntrack_tuple *tuple)
{
        const __be32 *ap;
        __be32 _addrs[2];
        ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
                                sizeof(u_int32_t) * 2, _addrs);
        if (ap == NULL)
                return false;

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

        return true;
}

static bool 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 true;
}

static int ipv4_print_tuple(struct seq_file *s,
                            const struct nf_conntrack_tuple *tuple)
{
        return seq_printf(s, "src=%pI4 dst=%pI4 ",
                          &tuple->src.u3.ip, &tuple->dst.u3.ip);
}

static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
                            unsigned int *dataoff, u_int8_t *protonum)
{
        const struct iphdr *iph;
        struct iphdr _iph;

        iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
        if (iph == NULL)
                return -NF_ACCEPT;

        /* Conntrack defragments packets, we might still see fragments
         * inside ICMP packets though. */
        if (iph->frag_off & htons(IP_OFFSET))
                return -NF_ACCEPT;

        *dataoff = nhoff + (iph->ihl << 2);
        *protonum = iph->protocol;

        /* Check bogus IP headers */
        if (*dataoff > skb->len) {
                pr_debug("nf_conntrack_ipv4: bogus IPv4 packet: "
                         "nhoff %u, ihl %u, skblen %u\n",
                         nhoff, iph->ihl << 2, skb->len);
                return -NF_ACCEPT;
        }

        return NF_ACCEPT;
}

static unsigned int ipv4_helper(unsigned int hooknum,
                                struct sk_buff *skb,
                                const struct net_device *in,
                                const struct net_device *out,
                                int (*okfn)(struct sk_buff *))
{
        struct nf_conn *ct;
        enum ip_conntrack_info ctinfo;
        const struct nf_conn_help *help;
        const struct nf_conntrack_helper *helper;

        /* This is where we call the helper: as the packet goes out. */
        ct = nf_ct_get(skb, &ctinfo);
        if (!ct || ctinfo == IP_CT_RELATED_REPLY)
                return NF_ACCEPT;

        help = nfct_help(ct);
        if (!help)
                return NF_ACCEPT;

        /* rcu_read_lock()ed by nf_hook_slow */
        helper = rcu_dereference(help->helper);
        if (!helper)
                return NF_ACCEPT;

        return helper->help(skb, skb_network_offset(skb) + ip_hdrlen(skb),
                            ct, ctinfo);
}

static unsigned int ipv4_confirm(unsigned int hooknum,
                                 struct sk_buff *skb,
                                 const struct net_device *in,
                                 const struct net_device *out,
                                 int (*okfn)(struct sk_buff *))
{
        struct nf_conn *ct;
        enum ip_conntrack_info ctinfo;

        ct = nf_ct_get(skb, &ctinfo);
        if (!ct || ctinfo == IP_CT_RELATED_REPLY)
                goto out;

        /* adjust seqs for loopback traffic only in outgoing direction */
        if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
            !nf_is_loopback_packet(skb)) {
                typeof(nf_nat_seq_adjust_hook) seq_adjust;

                seq_adjust = rcu_dereference(nf_nat_seq_adjust_hook);
                if (!seq_adjust ||
                    !seq_adjust(skb, ct, ctinfo, ip_hdrlen(skb))) {
                        NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
                        return NF_DROP;
                }
        }
out:
        /* We've seen it coming out the other side: confirm it */
        return nf_conntrack_confirm(skb);
}

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

static unsigned int ipv4_conntrack_local(unsigned int hooknum,
                                         struct sk_buff *skb,
                                         const struct net_device *in,
                                         const struct net_device *out,
                                         int (*okfn)(struct sk_buff *))
{
        /* root is playing with raw sockets. */
        if (skb->len < sizeof(struct iphdr) ||
            ip_hdrlen(skb) < sizeof(struct iphdr))
                return NF_ACCEPT;
        return nf_conntrack_in(dev_net(out), PF_INET, hooknum, skb);
}

/* Connection tracking may drop packets, but never alters them, so
   make it the first hook. */
static struct nf_hook_ops ipv4_conntrack_ops[] __read_mostly = {
        {
                .hook           = ipv4_conntrack_in,
                .owner          = THIS_MODULE,
                .pf             = NFPROTO_IPV4,
                .hooknum        = NF_INET_PRE_ROUTING,
                .priority       = NF_IP_PRI_CONNTRACK,
        },
        {
                .hook           = ipv4_conntrack_local,
                .owner          = THIS_MODULE,
                .pf             = NFPROTO_IPV4,
                .hooknum        = NF_INET_LOCAL_OUT,
                .priority       = NF_IP_PRI_CONNTRACK,
        },
        {
                .hook           = ipv4_helper,
                .owner          = THIS_MODULE,
                .pf             = NFPROTO_IPV4,
                .hooknum        = NF_INET_POST_ROUTING,
                .priority       = NF_IP_PRI_CONNTRACK_HELPER,
        },
        {
                .hook           = ipv4_confirm,
                .owner          = THIS_MODULE,
                .pf             = NFPROTO_IPV4,
                .hooknum        = NF_INET_POST_ROUTING,
                .priority       = NF_IP_PRI_CONNTRACK_CONFIRM,
        },
        {
                .hook           = ipv4_helper,
                .owner          = THIS_MODULE,
                .pf             = NFPROTO_IPV4,
                .hooknum        = NF_INET_LOCAL_IN,
                .priority       = NF_IP_PRI_CONNTRACK_HELPER,
        },
        {
                .hook           = ipv4_confirm,
                .owner          = THIS_MODULE,
                .pf             = NFPROTO_IPV4,
                .hooknum        = NF_INET_LOCAL_IN,
                .priority       = NF_IP_PRI_CONNTRACK_CONFIRM,
        },
};

#if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
static int log_invalid_proto_min = 0;
static int log_invalid_proto_max = 255;

static struct ctl_table ip_ct_sysctl_table[] = {
        {
                .procname       = "ip_conntrack_max",
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "ip_conntrack_count",
                .maxlen         = sizeof(int),
                .mode           = 0444,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "ip_conntrack_buckets",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0444,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "ip_conntrack_checksum",
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "ip_conntrack_log_invalid",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &log_invalid_proto_min,
                .extra2         = &log_invalid_proto_max,
        },
        { }
};
#endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */

/* 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)
{
        const struct inet_sock *inet = inet_sk(sk);
        const struct nf_conntrack_tuple_hash *h;
        struct nf_conntrack_tuple tuple;

        memset(&tuple, 0, sizeof(tuple));
        tuple.src.u3.ip = inet->inet_rcv_saddr;
        tuple.src.u.tcp.port = inet->inet_sport;
        tuple.dst.u3.ip = inet->inet_daddr;
        tuple.dst.u.tcp.port = inet->inet_dport;
        tuple.src.l3num = PF_INET;
        tuple.dst.protonum = sk->sk_protocol;

        /* We only do TCP and SCTP at the moment: is there a better way? */
        if (sk->sk_protocol != IPPROTO_TCP && sk->sk_protocol != IPPROTO_SCTP) {
                pr_debug("SO_ORIGINAL_DST: Not a TCP/SCTP socket\n");
                return -ENOPROTOOPT;
        }

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

        h = nf_conntrack_find_get(sock_net(sk), NF_CT_DEFAULT_ZONE, &tuple);
        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;
                memset(sin.sin_zero, 0, sizeof(sin.sin_zero));

                pr_debug("SO_ORIGINAL_DST: %pI4 %u\n",
                         &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;
        }
        pr_debug("SO_ORIGINAL_DST: Can't find %pI4/%u-%pI4/%u.\n",
                 &tuple.src.u3.ip, ntohs(tuple.src.u.tcp.port),
                 &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_nlattr(struct sk_buff *skb,
                                const struct nf_conntrack_tuple *tuple)
{
        if (nla_put_be32(skb, CTA_IP_V4_SRC, tuple->src.u3.ip) ||
            nla_put_be32(skb, CTA_IP_V4_DST, tuple->dst.u3.ip))
                goto nla_put_failure;
        return 0;

nla_put_failure:
        return -1;
}

static const struct nla_policy ipv4_nla_policy[CTA_IP_MAX+1] = {
        [CTA_IP_V4_SRC] = { .type = NLA_U32 },
        [CTA_IP_V4_DST] = { .type = NLA_U32 },
};

static int ipv4_nlattr_to_tuple(struct nlattr *tb[],
                                struct nf_conntrack_tuple *t)
{
        if (!tb[CTA_IP_V4_SRC] || !tb[CTA_IP_V4_DST])
                return -EINVAL;

        t->src.u3.ip = nla_get_be32(tb[CTA_IP_V4_SRC]);
        t->dst.u3.ip = nla_get_be32(tb[CTA_IP_V4_DST]);

        return 0;
}

static int ipv4_nlattr_tuple_size(void)
{
        return nla_policy_len(ipv4_nla_policy, CTA_IP_MAX + 1);
}
#endif

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

static int ipv4_init_net(struct net *net)
{
#if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
        struct nf_ip_net *in = &net->ct.nf_ct_proto;
        in->ctl_table = kmemdup(ip_ct_sysctl_table,
                                sizeof(ip_ct_sysctl_table),
                                GFP_KERNEL);
        if (!in->ctl_table)
                return -ENOMEM;

        in->ctl_table[0].data = &nf_conntrack_max;
        in->ctl_table[1].data = &net->ct.count;
        in->ctl_table[2].data = &net->ct.htable_size;
        in->ctl_table[3].data = &net->ct.sysctl_checksum;
        in->ctl_table[4].data = &net->ct.sysctl_log_invalid;
#endif
        return 0;
}

struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly = {
        .l3proto         = PF_INET,
        .name            = "ipv4",
        .pkt_to_tuple    = ipv4_pkt_to_tuple,
        .invert_tuple    = ipv4_invert_tuple,
        .print_tuple     = ipv4_print_tuple,
        .get_l4proto     = ipv4_get_l4proto,
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
        .tuple_to_nlattr = ipv4_tuple_to_nlattr,
        .nlattr_tuple_size = ipv4_nlattr_tuple_size,
        .nlattr_to_tuple = ipv4_nlattr_to_tuple,
        .nla_policy      = ipv4_nla_policy,
#endif
#if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
        .ctl_table_path  = "net/ipv4/netfilter",
#endif
        .init_net        = ipv4_init_net,
        .me              = THIS_MODULE,
};

module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
                  &nf_conntrack_htable_size, 0600);

MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
MODULE_ALIAS("ip_conntrack");
MODULE_LICENSE("GPL");

static int ipv4_net_init(struct net *net)
{
        int ret = 0;

        ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_tcp4);
        if (ret < 0) {
                pr_err("nf_conntrack_tcp4: pernet registration failed\n");
                goto out_tcp;
        }
        ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_udp4);
        if (ret < 0) {
                pr_err("nf_conntrack_udp4: pernet registration failed\n");
                goto out_udp;
        }
        ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_icmp);
        if (ret < 0) {
                pr_err("nf_conntrack_icmp4: pernet registration failed\n");
                goto out_icmp;
        }
        ret = nf_ct_l3proto_pernet_register(net, &nf_conntrack_l3proto_ipv4);
        if (ret < 0) {
                pr_err("nf_conntrack_ipv4: pernet registration failed\n");
                goto out_ipv4;
        }
        return 0;
out_ipv4:
        nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_icmp);
out_icmp:
        nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udp4);
out_udp:
        nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_tcp4);
out_tcp:
        return ret;
}

static void ipv4_net_exit(struct net *net)
{
        nf_ct_l3proto_pernet_unregister(net, &nf_conntrack_l3proto_ipv4);
        nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_icmp);
        nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udp4);
        nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_tcp4);
}

static struct pernet_operations ipv4_net_ops = {
        .init = ipv4_net_init,
        .exit = ipv4_net_exit,
};

static int __init nf_conntrack_l3proto_ipv4_init(void)
{
        int ret = 0;

        need_conntrack();
        nf_defrag_ipv4_enable();

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

        ret = register_pernet_subsys(&ipv4_net_ops);
        if (ret < 0) {
                pr_err("nf_conntrack_ipv4: can't register pernet ops\n");
                goto cleanup_sockopt;
        }

        ret = nf_register_hooks(ipv4_conntrack_ops,
                                ARRAY_SIZE(ipv4_conntrack_ops));
        if (ret < 0) {
                pr_err("nf_conntrack_ipv4: can't register hooks.\n");
                goto cleanup_pernet;
        }

        ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_tcp4);
        if (ret < 0) {
                pr_err("nf_conntrack_ipv4: can't register tcp4 proto.\n");
                goto cleanup_hooks;
        }

        ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_udp4);
        if (ret < 0) {
                pr_err("nf_conntrack_ipv4: can't register udp4 proto.\n");
                goto cleanup_tcp4;
        }

        ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_icmp);
        if (ret < 0) {
                pr_err("nf_conntrack_ipv4: can't register icmpv4 proto.\n");
                goto cleanup_udp4;
        }

        ret = nf_ct_l3proto_register(&nf_conntrack_l3proto_ipv4);
        if (ret < 0) {
                pr_err("nf_conntrack_ipv4: can't register ipv4 proto.\n");
                goto cleanup_icmpv4;
        }

#if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
        ret = nf_conntrack_ipv4_compat_init();
        if (ret < 0)
                goto cleanup_proto;
#endif
        return ret;
#if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
 cleanup_proto:
        nf_ct_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
#endif
 cleanup_icmpv4:
        nf_ct_l4proto_unregister(&nf_conntrack_l4proto_icmp);
 cleanup_udp4:
        nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udp4);
 cleanup_tcp4:
        nf_ct_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
 cleanup_hooks:
        nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
 cleanup_pernet:
        unregister_pernet_subsys(&ipv4_net_ops);
 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_ct_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
        nf_ct_l4proto_unregister(&nf_conntrack_l4proto_icmp);
        nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udp4);
        nf_ct_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
        nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
        unregister_pernet_subsys(&ipv4_net_ops);
        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);