Add the rt linux 4.1.3-rt3 as base

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

diff --git a/kernel/net/ipv4/netfilter/arpt_mangle.c b/kernel/net/ipv4/netfilter/arpt_mangle.c
new file mode 100644 (file)
index 0000000..a5e52a9
--- /dev/null
+++ b/kernel/net/ipv4/netfilter/arpt_mangle.c
@@ -0,0 +1,91 @@
+/* module that allows mangling of the arp payload */
+#include <linux/module.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_arp/arpt_mangle.h>
+#include <net/sock.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
+MODULE_DESCRIPTION("arptables arp payload mangle target");
+
+static unsigned int
+target(struct sk_buff *skb, const struct xt_action_param *par)
+{
+       const struct arpt_mangle *mangle = par->targinfo;
+       const struct arphdr *arp;
+       unsigned char *arpptr;
+       int pln, hln;
+
+       if (!skb_make_writable(skb, skb->len))
+               return NF_DROP;
+
+       arp = arp_hdr(skb);
+       arpptr = skb_network_header(skb) + sizeof(*arp);
+       pln = arp->ar_pln;
+       hln = arp->ar_hln;
+       /* We assume that pln and hln were checked in the match */
+       if (mangle->flags & ARPT_MANGLE_SDEV) {
+               if (ARPT_DEV_ADDR_LEN_MAX < hln ||
+                  (arpptr + hln > skb_tail_pointer(skb)))
+                       return NF_DROP;
+               memcpy(arpptr, mangle->src_devaddr, hln);
+       }
+       arpptr += hln;
+       if (mangle->flags & ARPT_MANGLE_SIP) {
+               if (ARPT_MANGLE_ADDR_LEN_MAX < pln ||
+                  (arpptr + pln > skb_tail_pointer(skb)))
+                       return NF_DROP;
+               memcpy(arpptr, &mangle->u_s.src_ip, pln);
+       }
+       arpptr += pln;
+       if (mangle->flags & ARPT_MANGLE_TDEV) {
+               if (ARPT_DEV_ADDR_LEN_MAX < hln ||
+                  (arpptr + hln > skb_tail_pointer(skb)))
+                       return NF_DROP;
+               memcpy(arpptr, mangle->tgt_devaddr, hln);
+       }
+       arpptr += hln;
+       if (mangle->flags & ARPT_MANGLE_TIP) {
+               if (ARPT_MANGLE_ADDR_LEN_MAX < pln ||
+                  (arpptr + pln > skb_tail_pointer(skb)))
+                       return NF_DROP;
+               memcpy(arpptr, &mangle->u_t.tgt_ip, pln);
+       }
+       return mangle->target;
+}
+
+static int checkentry(const struct xt_tgchk_param *par)
+{
+       const struct arpt_mangle *mangle = par->targinfo;
+
+       if (mangle->flags & ~ARPT_MANGLE_MASK ||
+           !(mangle->flags & ARPT_MANGLE_MASK))
+               return -EINVAL;
+
+       if (mangle->target != NF_DROP && mangle->target != NF_ACCEPT &&
+          mangle->target != XT_CONTINUE)
+               return -EINVAL;
+       return 0;
+}
+
+static struct xt_target arpt_mangle_reg __read_mostly = {
+       .name           = "mangle",
+       .family         = NFPROTO_ARP,
+       .target         = target,
+       .targetsize     = sizeof(struct arpt_mangle),
+       .checkentry     = checkentry,
+       .me             = THIS_MODULE,
+};
+
+static int __init arpt_mangle_init(void)
+{
+       return xt_register_target(&arpt_mangle_reg);
+}
+
+static void __exit arpt_mangle_fini(void)
+{
+       xt_unregister_target(&arpt_mangle_reg);
+}
+
+module_init(arpt_mangle_init);
+module_exit(arpt_mangle_fini);