These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / net / ipv4 / netfilter / nf_dup_ipv4.c

diff --git a/kernel/net/ipv4/netfilter/nf_dup_ipv4.c b/kernel/net/ipv4/netfilter/nf_dup_ipv4.c
new file mode 100644 (file)
index 0000000..ceb1873
--- /dev/null
+++ b/kernel/net/ipv4/netfilter/nf_dup_ipv4.c
@@ -0,0 +1,106 @@
+/*
+ * (C) 2007 by Sebastian Claßen <sebastian.classen@freenet.ag>
+ * (C) 2007-2010 by Jan Engelhardt <jengelh@medozas.de>
+ *
+ * Extracted from xt_TEE.c
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later, as
+ * published by the Free Software Foundation.
+ */
+#include <linux/ip.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/route.h>
+#include <linux/skbuff.h>
+#include <linux/netfilter.h>
+#include <net/checksum.h>
+#include <net/icmp.h>
+#include <net/ip.h>
+#include <net/route.h>
+#include <net/netfilter/ipv4/nf_dup_ipv4.h>
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
+#include <net/netfilter/nf_conntrack.h>
+#endif
+
+static bool nf_dup_ipv4_route(struct net *net, struct sk_buff *skb,
+                             const struct in_addr *gw, int oif)
+{
+       const struct iphdr *iph = ip_hdr(skb);
+       struct rtable *rt;
+       struct flowi4 fl4;
+
+       memset(&fl4, 0, sizeof(fl4));
+       if (oif != -1)
+               fl4.flowi4_oif = oif;
+
+       fl4.daddr = gw->s_addr;
+       fl4.flowi4_tos = RT_TOS(iph->tos);
+       fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
+       fl4.flowi4_flags = FLOWI_FLAG_KNOWN_NH;
+       rt = ip_route_output_key(net, &fl4);
+       if (IS_ERR(rt))
+               return false;
+
+       skb_dst_drop(skb);
+       skb_dst_set(skb, &rt->dst);
+       skb->dev      = rt->dst.dev;
+       skb->protocol = htons(ETH_P_IP);
+
+       return true;
+}
+
+void nf_dup_ipv4(struct net *net, struct sk_buff *skb, unsigned int hooknum,
+                const struct in_addr *gw, int oif)
+{
+       struct iphdr *iph;
+
+       if (this_cpu_read(nf_skb_duplicated))
+               return;
+       /*
+        * Copy the skb, and route the copy. Will later return %XT_CONTINUE for
+        * the original skb, which should continue on its way as if nothing has
+        * happened. The copy should be independently delivered to the gateway.
+        */
+       skb = pskb_copy(skb, GFP_ATOMIC);
+       if (skb == NULL)
+               return;
+
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
+       /* Avoid counting cloned packets towards the original connection. */
+       nf_conntrack_put(skb->nfct);
+       skb->nfct     = &nf_ct_untracked_get()->ct_general;
+       skb->nfctinfo = IP_CT_NEW;
+       nf_conntrack_get(skb->nfct);
+#endif
+       /*
+        * If we are in PREROUTING/INPUT, the checksum must be recalculated
+        * since the length could have changed as a result of defragmentation.
+        *
+        * We also decrease the TTL to mitigate potential loops between two
+        * hosts.
+        *
+        * Set %IP_DF so that the original source is notified of a potentially
+        * decreased MTU on the clone route. IPv6 does this too.
+        */
+       iph = ip_hdr(skb);
+       iph->frag_off |= htons(IP_DF);
+       if (hooknum == NF_INET_PRE_ROUTING ||
+           hooknum == NF_INET_LOCAL_IN)
+               --iph->ttl;
+       ip_send_check(iph);
+
+       if (nf_dup_ipv4_route(net, skb, gw, oif)) {
+               __this_cpu_write(nf_skb_duplicated, true);
+               ip_local_out(net, skb->sk, skb);
+               __this_cpu_write(nf_skb_duplicated, false);
+       } else {
+               kfree_skb(skb);
+       }
+}
+EXPORT_SYMBOL_GPL(nf_dup_ipv4);
+
+MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@freenet.ag>");
+MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
+MODULE_DESCRIPTION("nf_dup_ipv4: Duplicate IPv4 packet");
+MODULE_LICENSE("GPL");