Merge branch 'nf' of git://1984.lsi.us.es/net
[linux-2.6.git] / net / ipv4 / netfilter.c
index 4c637a1..4f47e06 100644 (file)
 /* IPv4 specific functions of netfilter core */
-
-#include <linux/config.h>
-#ifdef CONFIG_NETFILTER
-
 #include <linux/kernel.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter_ipv4.h>
-
 #include <linux/ip.h>
-#include <linux/tcp.h>
-#include <linux/udp.h>
-#include <linux/icmp.h>
+#include <linux/skbuff.h>
+#include <linux/gfp.h>
+#include <linux/export.h>
 #include <net/route.h>
 #include <net/xfrm.h>
 #include <net/ip.h>
+#include <net/netfilter/nf_queue.h>
 
 /* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
-int ip_route_me_harder(struct sk_buff **pskb)
+int ip_route_me_harder(struct sk_buff *skb, unsigned addr_type)
 {
-       struct iphdr *iph = (*pskb)->nh.iph;
+       struct net *net = dev_net(skb_dst(skb)->dev);
+       const struct iphdr *iph = ip_hdr(skb);
        struct rtable *rt;
-       struct flowi fl = {};
-       struct dst_entry *odst;
+       struct flowi4 fl4 = {};
+       __be32 saddr = iph->saddr;
+       __u8 flags = skb->sk ? inet_sk_flowi_flags(skb->sk) : 0;
        unsigned int hh_len;
 
+       if (addr_type == RTN_UNSPEC)
+               addr_type = inet_addr_type(net, saddr);
+       if (addr_type == RTN_LOCAL || addr_type == RTN_UNICAST)
+               flags |= FLOWI_FLAG_ANYSRC;
+       else
+               saddr = 0;
+
        /* some non-standard hacks like ipt_REJECT.c:send_reset() can cause
-        * packets with foreign saddr to appear on the NF_IP_LOCAL_OUT hook.
+        * packets with foreign saddr to appear on the NF_INET_LOCAL_OUT hook.
         */
-       if (inet_addr_type(iph->saddr) == RTN_LOCAL) {
-               fl.nl_u.ip4_u.daddr = iph->daddr;
-               fl.nl_u.ip4_u.saddr = iph->saddr;
-               fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
-               fl.oif = (*pskb)->sk ? (*pskb)->sk->sk_bound_dev_if : 0;
-#ifdef CONFIG_IP_ROUTE_FWMARK
-               fl.nl_u.ip4_u.fwmark = (*pskb)->nfmark;
-#endif
-               if (ip_route_output_key(&rt, &fl) != 0)
-                       return -1;
+       fl4.daddr = iph->daddr;
+       fl4.saddr = saddr;
+       fl4.flowi4_tos = RT_TOS(iph->tos);
+       fl4.flowi4_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0;
+       fl4.flowi4_mark = skb->mark;
+       fl4.flowi4_flags = flags;
+       rt = ip_route_output_key(net, &fl4);
+       if (IS_ERR(rt))
+               return -1;
 
-               /* Drop old route. */
-               dst_release((*pskb)->dst);
-               (*pskb)->dst = &rt->u.dst;
-       } else {
-               /* non-local src, find valid iif to satisfy
-                * rp-filter when calling ip_route_input. */
-               fl.nl_u.ip4_u.daddr = iph->saddr;
-               if (ip_route_output_key(&rt, &fl) != 0)
-                       return -1;
+       /* Drop old route. */
+       skb_dst_drop(skb);
+       skb_dst_set(skb, &rt->dst);
 
-               odst = (*pskb)->dst;
-               if (ip_route_input(*pskb, iph->daddr, iph->saddr,
-                                  RT_TOS(iph->tos), rt->u.dst.dev) != 0) {
-                       dst_release(&rt->u.dst);
-                       return -1;
-               }
-               dst_release(&rt->u.dst);
-               dst_release(odst);
-       }
-       
-       if ((*pskb)->dst->error)
+       if (skb_dst(skb)->error)
                return -1;
 
 #ifdef CONFIG_XFRM
-       if (!(IPCB(*pskb)->flags & IPSKB_XFRM_TRANSFORMED) &&
-           xfrm_decode_session(*pskb, &fl, AF_INET) == 0)
-               if (xfrm_lookup(&(*pskb)->dst, &fl, (*pskb)->sk, 0))
+       if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) &&
+           xfrm_decode_session(skb, flowi4_to_flowi(&fl4), AF_INET) == 0) {
+               struct dst_entry *dst = skb_dst(skb);
+               skb_dst_set(skb, NULL);
+               dst = xfrm_lookup(net, dst, flowi4_to_flowi(&fl4), skb->sk, 0);
+               if (IS_ERR(dst))
                        return -1;
+               skb_dst_set(skb, dst);
+       }
 #endif
 
        /* Change in oif may mean change in hh_len. */
-       hh_len = (*pskb)->dst->dev->hard_header_len;
-       if (skb_headroom(*pskb) < hh_len) {
-               struct sk_buff *nskb;
-
-               nskb = skb_realloc_headroom(*pskb, hh_len);
-               if (!nskb) 
-                       return -1;
-               if ((*pskb)->sk)
-                       skb_set_owner_w(nskb, (*pskb)->sk);
-               kfree_skb(*pskb);
-               *pskb = nskb;
-       }
+       hh_len = skb_dst(skb)->dev->hard_header_len;
+       if (skb_headroom(skb) < hh_len &&
+           pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)),
+                               0, GFP_ATOMIC))
+               return -1;
 
        return 0;
 }
 EXPORT_SYMBOL(ip_route_me_harder);
 
+#ifdef CONFIG_XFRM
+int ip_xfrm_me_harder(struct sk_buff *skb)
+{
+       struct flowi fl;
+       unsigned int hh_len;
+       struct dst_entry *dst;
+
+       if (IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED)
+               return 0;
+       if (xfrm_decode_session(skb, &fl, AF_INET) < 0)
+               return -1;
+
+       dst = skb_dst(skb);
+       if (dst->xfrm)
+               dst = ((struct xfrm_dst *)dst)->route;
+       dst_hold(dst);
+
+       dst = xfrm_lookup(dev_net(dst->dev), dst, &fl, skb->sk, 0);
+       if (IS_ERR(dst))
+               return -1;
+
+       skb_dst_drop(skb);
+       skb_dst_set(skb, dst);
+
+       /* Change in oif may mean change in hh_len. */
+       hh_len = skb_dst(skb)->dev->hard_header_len;
+       if (skb_headroom(skb) < hh_len &&
+           pskb_expand_head(skb, hh_len - skb_headroom(skb), 0, GFP_ATOMIC))
+               return -1;
+       return 0;
+}
+EXPORT_SYMBOL(ip_xfrm_me_harder);
+#endif
+
+void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
+EXPORT_SYMBOL(ip_nat_decode_session);
+
 /*
  * Extra routing may needed on local out, as the QUEUE target never
  * returns control to the table.
  */
 
 struct ip_rt_info {
-       u_int32_t daddr;
-       u_int32_t saddr;
+       __be32 daddr;
+       __be32 saddr;
        u_int8_t tos;
+       u_int32_t mark;
 };
 
-static void queue_save(const struct sk_buff *skb, struct nf_info *info)
+static void nf_ip_saveroute(const struct sk_buff *skb,
+                           struct nf_queue_entry *entry)
 {
-       struct ip_rt_info *rt_info = nf_info_reroute(info);
+       struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
 
-       if (info->hook == NF_IP_LOCAL_OUT) {
-               const struct iphdr *iph = skb->nh.iph;
+       if (entry->hook == NF_INET_LOCAL_OUT) {
+               const struct iphdr *iph = ip_hdr(skb);
 
                rt_info->tos = iph->tos;
                rt_info->daddr = iph->daddr;
                rt_info->saddr = iph->saddr;
+               rt_info->mark = skb->mark;
        }
 }
 
-static int queue_reroute(struct sk_buff **pskb, const struct nf_info *info)
+static int nf_ip_reroute(struct sk_buff *skb,
+                        const struct nf_queue_entry *entry)
 {
-       const struct ip_rt_info *rt_info = nf_info_reroute(info);
+       const struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
 
-       if (info->hook == NF_IP_LOCAL_OUT) {
-               struct iphdr *iph = (*pskb)->nh.iph;
+       if (entry->hook == NF_INET_LOCAL_OUT) {
+               const struct iphdr *iph = ip_hdr(skb);
 
-               if (!(iph->tos == rt_info->tos
-                     && iph->daddr == rt_info->daddr
-                     && iph->saddr == rt_info->saddr))
-                       return ip_route_me_harder(pskb);
+               if (!(iph->tos == rt_info->tos &&
+                     skb->mark == rt_info->mark &&
+                     iph->daddr == rt_info->daddr &&
+                     iph->saddr == rt_info->saddr))
+                       return ip_route_me_harder(skb, RTN_UNSPEC);
        }
        return 0;
 }
 
-static struct nf_queue_rerouter ip_reroute = {
-       .rer_size       = sizeof(struct ip_rt_info),
-       .save           = queue_save,
-       .reroute        = queue_reroute,
+__sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
+                           unsigned int dataoff, u_int8_t protocol)
+{
+       const struct iphdr *iph = ip_hdr(skb);
+       __sum16 csum = 0;
+
+       switch (skb->ip_summed) {
+       case CHECKSUM_COMPLETE:
+               if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN)
+                       break;
+               if ((protocol == 0 && !csum_fold(skb->csum)) ||
+                   !csum_tcpudp_magic(iph->saddr, iph->daddr,
+                                      skb->len - dataoff, protocol,
+                                      skb->csum)) {
+                       skb->ip_summed = CHECKSUM_UNNECESSARY;
+                       break;
+               }
+               /* fall through */
+       case CHECKSUM_NONE:
+               if (protocol == 0)
+                       skb->csum = 0;
+               else
+                       skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
+                                                      skb->len - dataoff,
+                                                      protocol, 0);
+               csum = __skb_checksum_complete(skb);
+       }
+       return csum;
+}
+EXPORT_SYMBOL(nf_ip_checksum);
+
+static __sum16 nf_ip_checksum_partial(struct sk_buff *skb, unsigned int hook,
+                                     unsigned int dataoff, unsigned int len,
+                                     u_int8_t protocol)
+{
+       const struct iphdr *iph = ip_hdr(skb);
+       __sum16 csum = 0;
+
+       switch (skb->ip_summed) {
+       case CHECKSUM_COMPLETE:
+               if (len == skb->len - dataoff)
+                       return nf_ip_checksum(skb, hook, dataoff, protocol);
+               /* fall through */
+       case CHECKSUM_NONE:
+               skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, protocol,
+                                              skb->len - dataoff, 0);
+               skb->ip_summed = CHECKSUM_NONE;
+               return __skb_checksum_complete_head(skb, dataoff + len);
+       }
+       return csum;
+}
+
+static int nf_ip_route(struct net *net, struct dst_entry **dst,
+                      struct flowi *fl, bool strict __always_unused)
+{
+       struct rtable *rt = ip_route_output_key(net, &fl->u.ip4);
+       if (IS_ERR(rt))
+               return PTR_ERR(rt);
+       *dst = &rt->dst;
+       return 0;
+}
+
+static const struct nf_afinfo nf_ip_afinfo = {
+       .family                 = AF_INET,
+       .checksum               = nf_ip_checksum,
+       .checksum_partial       = nf_ip_checksum_partial,
+       .route                  = nf_ip_route,
+       .saveroute              = nf_ip_saveroute,
+       .reroute                = nf_ip_reroute,
+       .route_key_size         = sizeof(struct ip_rt_info),
 };
 
-static int init(void)
+static int ipv4_netfilter_init(void)
 {
-       return nf_register_queue_rerouter(PF_INET, &ip_reroute);
+       return nf_register_afinfo(&nf_ip_afinfo);
 }
 
-static void fini(void)
+static void ipv4_netfilter_fini(void)
 {
-       nf_unregister_queue_rerouter(PF_INET);
+       nf_unregister_afinfo(&nf_ip_afinfo);
 }
 
-module_init(init);
-module_exit(fini);
+module_init(ipv4_netfilter_init);
+module_exit(ipv4_netfilter_fini);
 
-#endif /* CONFIG_NETFILTER */
+#ifdef CONFIG_SYSCTL
+struct ctl_path nf_net_ipv4_netfilter_sysctl_path[] = {
+       { .procname = "net", },
+       { .procname = "ipv4", },
+       { .procname = "netfilter", },
+       { }
+};
+EXPORT_SYMBOL_GPL(nf_net_ipv4_netfilter_sysctl_path);
+#endif /* CONFIG_SYSCTL */