--- /dev/null
+/* IPv4 specific functions of netfilter core */
+#include <linux/kernel.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/ip.h>
+#include <net/route.h>
+#include <net/xfrm.h>
+#include <net/ip.h>
+
+/* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
+int ip_route_me_harder(struct sk_buff **pskb)
+{
+ struct iphdr *iph = (*pskb)->nh.iph;
+ struct rtable *rt;
+ struct flowi fl = {};
+ struct dst_entry *odst;
+ unsigned int hh_len;
+
+ /* 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.
+ */
+ 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;
+
+ /* 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;
+
+ 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)
+ 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))
+ return -1;
+#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;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(ip_route_me_harder);
+
+#ifdef CONFIG_XFRM
+int ip_xfrm_me_harder(struct sk_buff **pskb)
+{
+ struct flowi fl;
+ unsigned int hh_len;
+ struct dst_entry *dst;
+
+ if (IPCB(*pskb)->flags & IPSKB_XFRM_TRANSFORMED)
+ return 0;
+ if (xfrm_decode_session(*pskb, &fl, AF_INET) < 0)
+ return -1;
+
+ dst = (*pskb)->dst;
+ if (dst->xfrm)
+ dst = ((struct xfrm_dst *)dst)->route;
+ dst_hold(dst);
+
+ if (xfrm_lookup(&dst, &fl, (*pskb)->sk, 0) < 0)
+ return -1;
+
+ dst_release((*pskb)->dst);
+ (*pskb)->dst = dst;
+
+ /* 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;
+ }
+ 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;
+ u_int8_t tos;
+};
+
+static void nf_ip_saveroute(const struct sk_buff *skb, struct nf_info *info)
+{
+ struct ip_rt_info *rt_info = nf_info_reroute(info);
+
+ if (info->hook == NF_IP_LOCAL_OUT) {
+ const struct iphdr *iph = skb->nh.iph;
+
+ rt_info->tos = iph->tos;
+ rt_info->daddr = iph->daddr;
+ rt_info->saddr = iph->saddr;
+ }
+}
+
+static int nf_ip_reroute(struct sk_buff **pskb, const struct nf_info *info)
+{
+ const struct ip_rt_info *rt_info = nf_info_reroute(info);
+
+ if (info->hook == NF_IP_LOCAL_OUT) {
+ struct iphdr *iph = (*pskb)->nh.iph;
+
+ if (!(iph->tos == rt_info->tos
+ && iph->daddr == rt_info->daddr
+ && iph->saddr == rt_info->saddr))
+ return ip_route_me_harder(pskb);
+ }
+ return 0;
+}
+
+unsigned int nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
+ unsigned int dataoff, u_int8_t protocol)
+{
+ struct iphdr *iph = skb->nh.iph;
+ unsigned int csum = 0;
+
+ switch (skb->ip_summed) {
+ case CHECKSUM_HW:
+ if (hook != NF_IP_PRE_ROUTING && hook != NF_IP_LOCAL_IN)
+ break;
+ if ((protocol == 0 && !(u16)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 struct nf_afinfo nf_ip_afinfo = {
+ .family = AF_INET,
+ .checksum = nf_ip_checksum,
+ .saveroute = nf_ip_saveroute,
+ .reroute = nf_ip_reroute,
+ .route_key_size = sizeof(struct ip_rt_info),
+};
+
+static int ipv4_netfilter_init(void)
+{
+ return nf_register_afinfo(&nf_ip_afinfo);
+}
+
+static void ipv4_netfilter_fini(void)
+{
+ nf_unregister_afinfo(&nf_ip_afinfo);
+}
+
+module_init(ipv4_netfilter_init);
+module_exit(ipv4_netfilter_fini);
git://git.onelab.eu / linux-2.6.git / blobdiff