v4.19.13 snapshot.
diff --git a/net/ipv4/protocol.c b/net/ipv4/protocol.c
new file mode 100644
index 0000000..32a691b
--- /dev/null
+++ b/net/ipv4/protocol.c
@@ -0,0 +1,79 @@
+/*
+ * INET An implementation of the TCP/IP protocol suite for the LINUX
+ * operating system. INET is implemented using the BSD Socket
+ * interface as the means of communication with the user level.
+ *
+ * INET protocol dispatch tables.
+ *
+ * Authors: Ross Biro
+ * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
+ *
+ * Fixes:
+ * Alan Cox : Ahah! udp icmp errors don't work because
+ * udp_err is never called!
+ * Alan Cox : Added new fields for init and ready for
+ * proper fragmentation (_NO_ 4K limits!)
+ * Richard Colella : Hang on hash collision
+ * Vince Laviano : Modified inet_del_protocol() to correctly
+ * maintain copy bit.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#include <linux/cache.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/spinlock.h>
+#include <net/protocol.h>
+
+struct net_protocol __rcu *inet_protos[MAX_INET_PROTOS] __read_mostly;
+const struct net_offload __rcu *inet_offloads[MAX_INET_PROTOS] __read_mostly;
+EXPORT_SYMBOL(inet_offloads);
+
+int inet_add_protocol(const struct net_protocol *prot, unsigned char protocol)
+{
+ if (!prot->netns_ok) {
+ pr_err("Protocol %u is not namespace aware, cannot register.\n",
+ protocol);
+ return -EINVAL;
+ }
+
+ return !cmpxchg((const struct net_protocol **)&inet_protos[protocol],
+ NULL, prot) ? 0 : -1;
+}
+EXPORT_SYMBOL(inet_add_protocol);
+
+int inet_add_offload(const struct net_offload *prot, unsigned char protocol)
+{
+ return !cmpxchg((const struct net_offload **)&inet_offloads[protocol],
+ NULL, prot) ? 0 : -1;
+}
+EXPORT_SYMBOL(inet_add_offload);
+
+int inet_del_protocol(const struct net_protocol *prot, unsigned char protocol)
+{
+ int ret;
+
+ ret = (cmpxchg((const struct net_protocol **)&inet_protos[protocol],
+ prot, NULL) == prot) ? 0 : -1;
+
+ synchronize_net();
+
+ return ret;
+}
+EXPORT_SYMBOL(inet_del_protocol);
+
+int inet_del_offload(const struct net_offload *prot, unsigned char protocol)
+{
+ int ret;
+
+ ret = (cmpxchg((const struct net_offload **)&inet_offloads[protocol],
+ prot, NULL) == prot) ? 0 : -1;
+
+ synchronize_net();
+
+ return ret;
+}
+EXPORT_SYMBOL(inet_del_offload);