diff options
Diffstat (limited to 'net/ipv4/netfilter/ip_nat_core.c')
| -rw-r--r-- | net/ipv4/netfilter/ip_nat_core.c | 634 |
1 files changed, 0 insertions, 634 deletions
diff --git a/net/ipv4/netfilter/ip_nat_core.c b/net/ipv4/netfilter/ip_nat_core.c deleted file mode 100644 index 40737fdbe9a7..000000000000 --- a/net/ipv4/netfilter/ip_nat_core.c +++ /dev/null @@ -1,634 +0,0 @@ -/* NAT for netfilter; shared with compatibility layer. */ - -/* (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. - */ - -#include <linux/module.h> -#include <linux/types.h> -#include <linux/timer.h> -#include <linux/skbuff.h> -#include <linux/netfilter_ipv4.h> -#include <linux/vmalloc.h> -#include <net/checksum.h> -#include <net/icmp.h> -#include <net/ip.h> -#include <net/tcp.h> /* For tcp_prot in getorigdst */ -#include <linux/icmp.h> -#include <linux/udp.h> -#include <linux/jhash.h> - -#include <linux/netfilter_ipv4/ip_conntrack.h> -#include <linux/netfilter_ipv4/ip_conntrack_core.h> -#include <linux/netfilter_ipv4/ip_conntrack_protocol.h> -#include <linux/netfilter_ipv4/ip_nat.h> -#include <linux/netfilter_ipv4/ip_nat_protocol.h> -#include <linux/netfilter_ipv4/ip_nat_core.h> -#include <linux/netfilter_ipv4/ip_nat_helper.h> -#include <linux/netfilter_ipv4/ip_conntrack_helper.h> - -#if 0 -#define DEBUGP printk -#else -#define DEBUGP(format, args...) -#endif - -DEFINE_RWLOCK(ip_nat_lock); - -/* Calculated at init based on memory size */ -static unsigned int ip_nat_htable_size; - -static struct list_head *bysource; - -#define MAX_IP_NAT_PROTO 256 -static struct ip_nat_protocol *ip_nat_protos[MAX_IP_NAT_PROTO]; - -static inline struct ip_nat_protocol * -__ip_nat_proto_find(u_int8_t protonum) -{ - return rcu_dereference(ip_nat_protos[protonum]); -} - -struct ip_nat_protocol * -ip_nat_proto_find_get(u_int8_t protonum) -{ - struct ip_nat_protocol *p; - - rcu_read_lock(); - p = __ip_nat_proto_find(protonum); - if (!try_module_get(p->me)) - p = &ip_nat_unknown_protocol; - rcu_read_unlock(); - - return p; -} -EXPORT_SYMBOL_GPL(ip_nat_proto_find_get); - -void -ip_nat_proto_put(struct ip_nat_protocol *p) -{ - module_put(p->me); -} -EXPORT_SYMBOL_GPL(ip_nat_proto_put); - -/* We keep an extra hash for each conntrack, for fast searching. */ -static inline unsigned int -hash_by_src(const struct ip_conntrack_tuple *tuple) -{ - /* Original src, to ensure we map it consistently if poss. */ - return jhash_3words((__force u32)tuple->src.ip, tuple->src.u.all, - tuple->dst.protonum, 0) % ip_nat_htable_size; -} - -/* Noone using conntrack by the time this called. */ -static void ip_nat_cleanup_conntrack(struct ip_conntrack *conn) -{ - if (!(conn->status & IPS_NAT_DONE_MASK)) - return; - - write_lock_bh(&ip_nat_lock); - list_del(&conn->nat.info.bysource); - write_unlock_bh(&ip_nat_lock); -} - -/* Is this tuple already taken? (not by us) */ -int -ip_nat_used_tuple(const struct ip_conntrack_tuple *tuple, - const struct ip_conntrack *ignored_conntrack) -{ - /* Conntrack tracking doesn't keep track of outgoing tuples; only - incoming ones. NAT means they don't have a fixed mapping, - so we invert the tuple and look for the incoming reply. - - We could keep a separate hash if this proves too slow. */ - struct ip_conntrack_tuple reply; - - invert_tuplepr(&reply, tuple); - return ip_conntrack_tuple_taken(&reply, ignored_conntrack); -} -EXPORT_SYMBOL(ip_nat_used_tuple); - -/* If we source map this tuple so reply looks like reply_tuple, will - * that meet the constraints of range. */ -static int -in_range(const struct ip_conntrack_tuple *tuple, - const struct ip_nat_range *range) -{ - struct ip_nat_protocol *proto; - int ret = 0; - - /* If we are supposed to map IPs, then we must be in the - range specified, otherwise let this drag us onto a new src IP. */ - if (range->flags & IP_NAT_RANGE_MAP_IPS) { - if (ntohl(tuple->src.ip) < ntohl(range->min_ip) - || ntohl(tuple->src.ip) > ntohl(range->max_ip)) - return 0; - } - - rcu_read_lock(); - proto = __ip_nat_proto_find(tuple->dst.protonum); - if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) - || proto->in_range(tuple, IP_NAT_MANIP_SRC, - &range->min, &range->max)) - ret = 1; - rcu_read_unlock(); - - return ret; -} - -static inline int -same_src(const struct ip_conntrack *ct, - const struct ip_conntrack_tuple *tuple) -{ - return (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum - == tuple->dst.protonum - && ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip - == tuple->src.ip - && ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.all - == tuple->src.u.all); -} - -/* Only called for SRC manip */ -static int -find_appropriate_src(const struct ip_conntrack_tuple *tuple, - struct ip_conntrack_tuple *result, - const struct ip_nat_range *range) -{ - unsigned int h = hash_by_src(tuple); - struct ip_conntrack *ct; - - read_lock_bh(&ip_nat_lock); - list_for_each_entry(ct, &bysource[h], nat.info.bysource) { - if (same_src(ct, tuple)) { - /* Copy source part from reply tuple. */ - invert_tuplepr(result, - &ct->tuplehash[IP_CT_DIR_REPLY].tuple); - result->dst = tuple->dst; - - if (in_range(result, range)) { - read_unlock_bh(&ip_nat_lock); - return 1; - } - } - } - read_unlock_bh(&ip_nat_lock); - return 0; -} - -/* For [FUTURE] fragmentation handling, we want the least-used - src-ip/dst-ip/proto triple. Fairness doesn't come into it. Thus - if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports - 1-65535, we don't do pro-rata allocation based on ports; we choose - the ip with the lowest src-ip/dst-ip/proto usage. -*/ -static void -find_best_ips_proto(struct ip_conntrack_tuple *tuple, - const struct ip_nat_range *range, - const struct ip_conntrack *conntrack, - enum ip_nat_manip_type maniptype) -{ - __be32 *var_ipp; - /* Host order */ - u_int32_t minip, maxip, j; - - /* No IP mapping? Do nothing. */ - if (!(range->flags & IP_NAT_RANGE_MAP_IPS)) - return; - - if (maniptype == IP_NAT_MANIP_SRC) - var_ipp = &tuple->src.ip; - else - var_ipp = &tuple->dst.ip; - - /* Fast path: only one choice. */ - if (range->min_ip == range->max_ip) { - *var_ipp = range->min_ip; - return; - } - - /* Hashing source and destination IPs gives a fairly even - * spread in practice (if there are a small number of IPs - * involved, there usually aren't that many connections - * anyway). The consistency means that servers see the same - * client coming from the same IP (some Internet Banking sites - * like this), even across reboots. */ - minip = ntohl(range->min_ip); - maxip = ntohl(range->max_ip); - j = jhash_2words((__force u32)tuple->src.ip, (__force u32)tuple->dst.ip, 0); - *var_ipp = htonl(minip + j % (maxip - minip + 1)); -} - -/* Manipulate the tuple into the range given. For NF_IP_POST_ROUTING, - * we change the source to map into the range. For NF_IP_PRE_ROUTING - * and NF_IP_LOCAL_OUT, we change the destination to map into the - * range. It might not be possible to get a unique tuple, but we try. - * At worst (or if we race), we will end up with a final duplicate in - * __ip_conntrack_confirm and drop the packet. */ -static void -get_unique_tuple(struct ip_conntrack_tuple *tuple, - const struct ip_conntrack_tuple *orig_tuple, - const struct ip_nat_range *range, - struct ip_conntrack *conntrack, - enum ip_nat_manip_type maniptype) -{ - struct ip_nat_protocol *proto; - - /* 1) If this srcip/proto/src-proto-part is currently mapped, - and that same mapping gives a unique tuple within the given - range, use that. - - This is only required for source (ie. NAT/masq) mappings. - So far, we don't do local source mappings, so multiple - manips not an issue. */ - if (maniptype == IP_NAT_MANIP_SRC) { - if (find_appropriate_src(orig_tuple, tuple, range)) { - DEBUGP("get_unique_tuple: Found current src map\n"); - if (!(range->flags & IP_NAT_RANGE_PROTO_RANDOM)) - if (!ip_nat_used_tuple(tuple, conntrack)) - return; - } - } - - /* 2) Select the least-used IP/proto combination in the given - range. */ - *tuple = *orig_tuple; - find_best_ips_proto(tuple, range, conntrack, maniptype); - - /* 3) The per-protocol part of the manip is made to map into - the range to make a unique tuple. */ - - rcu_read_lock(); - proto = __ip_nat_proto_find(orig_tuple->dst.protonum); - - /* Change protocol info to have some randomization */ - if (range->flags & IP_NAT_RANGE_PROTO_RANDOM) { - proto->unique_tuple(tuple, range, maniptype, conntrack); - goto out; - } - - /* Only bother mapping if it's not already in range and unique */ - if ((!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) - || proto->in_range(tuple, maniptype, &range->min, &range->max)) - && !ip_nat_used_tuple(tuple, conntrack)) - goto out; - - /* Last change: get protocol to try to obtain unique tuple. */ - proto->unique_tuple(tuple, range, maniptype, conntrack); -out: - rcu_read_unlock(); -} - -unsigned int -ip_nat_setup_info(struct ip_conntrack *conntrack, - const struct ip_nat_range *range, - unsigned int hooknum) -{ - struct ip_conntrack_tuple curr_tuple, new_tuple; - struct ip_nat_info *info = &conntrack->nat.info; - int have_to_hash = !(conntrack->status & IPS_NAT_DONE_MASK); - enum ip_nat_manip_type maniptype = HOOK2MANIP(hooknum); - - IP_NF_ASSERT(hooknum == NF_IP_PRE_ROUTING - || hooknum == NF_IP_POST_ROUTING - || hooknum == NF_IP_LOCAL_IN - || hooknum == NF_IP_LOCAL_OUT); - BUG_ON(ip_nat_initialized(conntrack, maniptype)); - - /* What we've got will look like inverse of reply. Normally - this is what is in the conntrack, except for prior - manipulations (future optimization: if num_manips == 0, - orig_tp = - conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple) */ - invert_tuplepr(&curr_tuple, - &conntrack->tuplehash[IP_CT_DIR_REPLY].tuple); - - get_unique_tuple(&new_tuple, &curr_tuple, range, conntrack, maniptype); - - if (!ip_ct_tuple_equal(&new_tuple, &curr_tuple)) { - struct ip_conntrack_tuple reply; - - /* Alter conntrack table so will recognize replies. */ - invert_tuplepr(&reply, &new_tuple); - ip_conntrack_alter_reply(conntrack, &reply); - - /* Non-atomic: we own this at the moment. */ - if (maniptype == IP_NAT_MANIP_SRC) - conntrack->status |= IPS_SRC_NAT; - else - conntrack->status |= IPS_DST_NAT; - } - - /* Place in source hash if this is the first time. */ - if (have_to_hash) { - unsigned int srchash - = hash_by_src(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL] - .tuple); - write_lock_bh(&ip_nat_lock); - list_add(&info->bysource, &bysource[srchash]); - write_unlock_bh(&ip_nat_lock); - } - - /* It's done. */ - if (maniptype == IP_NAT_MANIP_DST) - set_bit(IPS_DST_NAT_DONE_BIT, &conntrack->status); - else - set_bit(IPS_SRC_NAT_DONE_BIT, &conntrack->status); - - return NF_ACCEPT; -} -EXPORT_SYMBOL(ip_nat_setup_info); - -/* Returns true if succeeded. */ -static int -manip_pkt(u_int16_t proto, - struct sk_buff **pskb, - unsigned int iphdroff, - const struct ip_conntrack_tuple *target, - enum ip_nat_manip_type maniptype) -{ - struct iphdr *iph; - struct ip_nat_protocol *p; - - if (!skb_make_writable(pskb, iphdroff + sizeof(*iph))) - return 0; - - iph = (void *)(*pskb)->data + iphdroff; - - /* Manipulate protcol part. */ - - /* rcu_read_lock()ed by nf_hook_slow */ - p = __ip_nat_proto_find(proto); - if (!p->manip_pkt(pskb, iphdroff, target, maniptype)) - return 0; - - iph = (void *)(*pskb)->data + iphdroff; - - if (maniptype == IP_NAT_MANIP_SRC) { - nf_csum_replace4(&iph->check, iph->saddr, target->src.ip); - iph->saddr = target->src.ip; - } else { - nf_csum_replace4(&iph->check, iph->daddr, target->dst.ip); - iph->daddr = target->dst.ip; - } - return 1; -} - -/* Do packet manipulations according to ip_nat_setup_info. */ -unsigned int ip_nat_packet(struct ip_conntrack *ct, - enum ip_conntrack_info ctinfo, - unsigned int hooknum, - struct sk_buff **pskb) -{ - enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); - unsigned long statusbit; - enum ip_nat_manip_type mtype = HOOK2MANIP(hooknum); - - if (mtype == IP_NAT_MANIP_SRC) - statusbit = IPS_SRC_NAT; - else - statusbit = IPS_DST_NAT; - - /* Invert if this is reply dir. */ - if (dir == IP_CT_DIR_REPLY) - statusbit ^= IPS_NAT_MASK; - - /* Non-atomic: these bits don't change. */ - if (ct->status & statusbit) { - struct ip_conntrack_tuple target; - - /* We are aiming to look like inverse of other direction. */ - invert_tuplepr(&target, &ct->tuplehash[!dir].tuple); - - if (!manip_pkt(target.dst.protonum, pskb, 0, &target, mtype)) - return NF_DROP; - } - return NF_ACCEPT; -} -EXPORT_SYMBOL_GPL(ip_nat_packet); - -/* Dir is direction ICMP is coming from (opposite to packet it contains) */ -int ip_nat_icmp_reply_translation(struct ip_conntrack *ct, - enum ip_conntrack_info ctinfo, - unsigned int hooknum, - struct sk_buff **pskb) -{ - struct { - struct icmphdr icmp; - struct iphdr ip; - } *inside; - struct ip_conntrack_protocol *proto; - struct ip_conntrack_tuple inner, target; - int hdrlen = (*pskb)->nh.iph->ihl * 4; - enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); - unsigned long statusbit; - enum ip_nat_manip_type manip = HOOK2MANIP(hooknum); - - if (!skb_make_writable(pskb, hdrlen + sizeof(*inside))) - return 0; - - inside = (void *)(*pskb)->data + (*pskb)->nh.iph->ihl*4; - - /* We're actually going to mangle it beyond trivial checksum - adjustment, so make sure the current checksum is correct. */ - if (nf_ip_checksum(*pskb, hooknum, hdrlen, 0)) - return 0; - - /* Must be RELATED */ - IP_NF_ASSERT((*pskb)->nfctinfo == IP_CT_RELATED || - (*pskb)->nfctinfo == IP_CT_RELATED+IP_CT_IS_REPLY); - - /* Redirects on non-null nats must be dropped, else they'll - start talking to each other without our translation, and be - confused... --RR */ - if (inside->icmp.type == ICMP_REDIRECT) { - /* If NAT isn't finished, assume it and drop. */ - if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK) - return 0; - - if (ct->status & IPS_NAT_MASK) - return 0; - } - - DEBUGP("icmp_reply_translation: translating error %p manp %u dir %s\n", - *pskb, manip, dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY"); - - /* rcu_read_lock()ed by nf_hook_slow */ - proto = __ip_conntrack_proto_find(inside->ip.protocol); - if (!ip_ct_get_tuple(&inside->ip, *pskb, (*pskb)->nh.iph->ihl*4 + - sizeof(struct icmphdr) + inside->ip.ihl*4, - &inner, proto)) - return 0; - - /* Change inner back to look like incoming packet. We do the - opposite manip on this hook to normal, because it might not - pass all hooks (locally-generated ICMP). Consider incoming - packet: PREROUTING (DST manip), routing produces ICMP, goes - through POSTROUTING (which must correct the DST manip). */ - if (!manip_pkt(inside->ip.protocol, pskb, - (*pskb)->nh.iph->ihl*4 - + sizeof(inside->icmp), - &ct->tuplehash[!dir].tuple, - !manip)) - return 0; - - if ((*pskb)->ip_summed != CHECKSUM_PARTIAL) { - /* Reloading "inside" here since manip_pkt inner. */ - inside = (void *)(*pskb)->data + (*pskb)->nh.iph->ihl*4; - inside->icmp.checksum = 0; - inside->icmp.checksum = csum_fold(skb_checksum(*pskb, hdrlen, - (*pskb)->len - hdrlen, - 0)); - } - - /* Change outer to look the reply to an incoming packet - * (proto 0 means don't invert per-proto part). */ - if (manip == IP_NAT_MANIP_SRC) - statusbit = IPS_SRC_NAT; - else - statusbit = IPS_DST_NAT; - - /* Invert if this is reply dir. */ - if (dir == IP_CT_DIR_REPLY) - statusbit ^= IPS_NAT_MASK; - - if (ct->status & statusbit) { - invert_tuplepr(&target, &ct->tuplehash[!dir].tuple); - if (!manip_pkt(0, pskb, 0, &target, manip)) - return 0; - } - - return 1; -} -EXPORT_SYMBOL_GPL(ip_nat_icmp_reply_translation); - -/* Protocol registration. */ -int ip_nat_protocol_register(struct ip_nat_protocol *proto) -{ - int ret = 0; - - write_lock_bh(&ip_nat_lock); - if (ip_nat_protos[proto->protonum] != &ip_nat_unknown_protocol) { - ret = -EBUSY; - goto out; - } - rcu_assign_pointer(ip_nat_protos[proto->protonum], proto); - out: - write_unlock_bh(&ip_nat_lock); - return ret; -} -EXPORT_SYMBOL(ip_nat_protocol_register); - -/* Noone stores the protocol anywhere; simply delete it. */ -void ip_nat_protocol_unregister(struct ip_nat_protocol *proto) -{ - write_lock_bh(&ip_nat_lock); - rcu_assign_pointer(ip_nat_protos[proto->protonum], - &ip_nat_unknown_protocol); - write_unlock_bh(&ip_nat_lock); - synchronize_rcu(); -} -EXPORT_SYMBOL(ip_nat_protocol_unregister); - -#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \ - defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE) -int -ip_nat_port_range_to_nfattr(struct sk_buff *skb, - const struct ip_nat_range *range) -{ - NFA_PUT(skb, CTA_PROTONAT_PORT_MIN, sizeof(__be16), - &range->min.tcp.port); - NFA_PUT(skb, CTA_PROTONAT_PORT_MAX, sizeof(__be16), - &range->max.tcp.port); - - return 0; - -nfattr_failure: - return -1; -} - -int -ip_nat_port_nfattr_to_range(struct nfattr *tb[], struct ip_nat_range *range) -{ - int ret = 0; - - /* we have to return whether we actually parsed something or not */ - - if (tb[CTA_PROTONAT_PORT_MIN-1]) { - ret = 1; - range->min.tcp.port = - *(__be16 *)NFA_DATA(tb[CTA_PROTONAT_PORT_MIN-1]); - } - - if (!tb[CTA_PROTONAT_PORT_MAX-1]) { - if (ret) - range->max.tcp.port = range->min.tcp.port; - } else { - ret = 1; - range->max.tcp.port = - *(__be16 *)NFA_DATA(tb[CTA_PROTONAT_PORT_MAX-1]); - } - - return ret; -} -EXPORT_SYMBOL_GPL(ip_nat_port_nfattr_to_range); -EXPORT_SYMBOL_GPL(ip_nat_port_range_to_nfattr); -#endif - -static int __init ip_nat_init(void) -{ - size_t i; - - /* Leave them the same for the moment. */ - ip_nat_htable_size = ip_conntrack_htable_size; - - /* One vmalloc for both hash tables */ - bysource = vmalloc(sizeof(struct list_head) * ip_nat_htable_size); - if (!bysource) - return -ENOMEM; - - /* Sew in builtin protocols. */ - write_lock_bh(&ip_nat_lock); - for (i = 0; i < MAX_IP_NAT_PROTO; i++) - rcu_assign_pointer(ip_nat_protos[i], &ip_nat_unknown_protocol); - rcu_assign_pointer(ip_nat_protos[IPPROTO_TCP], &ip_nat_protocol_tcp); - rcu_assign_pointer(ip_nat_protos[IPPROTO_UDP], &ip_nat_protocol_udp); - rcu_assign_pointer(ip_nat_protos[IPPROTO_ICMP], &ip_nat_protocol_icmp); - write_unlock_bh(&ip_nat_lock); - - for (i = 0; i < ip_nat_htable_size; i++) { - INIT_LIST_HEAD(&bysource[i]); - } - - /* FIXME: Man, this is a hack. <SIGH> */ - IP_NF_ASSERT(rcu_dereference(ip_conntrack_destroyed) == NULL); - rcu_assign_pointer(ip_conntrack_destroyed, ip_nat_cleanup_conntrack); - - /* Initialize fake conntrack so that NAT will skip it */ - ip_conntrack_untracked.status |= IPS_NAT_DONE_MASK; - return 0; -} - -/* Clear NAT section of all conntracks, in case we're loaded again. */ -static int clean_nat(struct ip_conntrack *i, void *data) -{ - memset(&i->nat, 0, sizeof(i->nat)); - i->status &= ~(IPS_NAT_MASK | IPS_NAT_DONE_MASK | IPS_SEQ_ADJUST); - return 0; -} - -static void __exit ip_nat_cleanup(void) -{ - ip_ct_iterate_cleanup(&clean_nat, NULL); - rcu_assign_pointer(ip_conntrack_destroyed, NULL); - synchronize_rcu(); - vfree(bysource); -} - -MODULE_LICENSE("GPL"); - -module_init(ip_nat_init); -module_exit(ip_nat_cleanup); |