22 files changed, 29 insertions, 478 deletions

diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index e77872c93c20..10b91ebdf213 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1,13 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Packet matching code.
  *
  * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  * Copyright (C) 2000-2005 Netfilter Core Team <coreteam@netfilter.org>
  * Copyright (C) 2006-2010 Patrick McHardy <kaber@trash.net>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 #include <linux/cache.h>
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index a2a88ab07f7b..4d6bf7ac0792 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -1,13 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* Cluster IP hashmark target
  * (C) 2003-2004 by Harald Welte <laforge@netfilter.org>
  * based on ideas of Fabio Olive Leite <olive@unixforge.org>
  *
  * Development of this code funded by SuSE Linux AG, http://www.suse.com/
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 #include <linux/module.h>
diff --git a/net/ipv4/netfilter/ipt_ECN.c b/net/ipv4/netfilter/ipt_ECN.c
index 9f6751893660..5930d3b02555 100644
--- a/net/ipv4/netfilter/ipt_ECN.c
+++ b/net/ipv4/netfilter/ipt_ECN.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* iptables module for the IPv4 and TCP ECN bits, Version 1.5
  *
  * (C) 2002 by Harald Welte <laforge@netfilter.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
 */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 #include <linux/in.h>
diff --git a/net/ipv4/netfilter/ipt_REJECT.c b/net/ipv4/netfilter/ipt_REJECT.c
index e8bed3390e58..e16b98ee6266 100644
--- a/net/ipv4/netfilter/ipt_REJECT.c
+++ b/net/ipv4/netfilter/ipt_REJECT.c
@@ -1,13 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * This is a module which is used for rejecting packets.
  */
 
 /* (C) 1999-2001 Paul `Rusty' Russell
  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 #include <linux/module.h>
diff --git a/net/ipv4/netfilter/ipt_SYNPROXY.c b/net/ipv4/netfilter/ipt_SYNPROXY.c
index 690b17ef6a44..8e7f84ec783d 100644
--- a/net/ipv4/netfilter/ipt_SYNPROXY.c
+++ b/net/ipv4/netfilter/ipt_SYNPROXY.c
@@ -1,263 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2013 Patrick McHardy <kaber@trash.net>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 
-#include <linux/module.h>
-#include <linux/skbuff.h>
-#include <net/tcp.h>
-
 #include <linux/netfilter_ipv4/ip_tables.h>
 #include <linux/netfilter/x_tables.h>
 #include <linux/netfilter/xt_SYNPROXY.h>
-#include <net/netfilter/nf_conntrack.h>
-#include <net/netfilter/nf_conntrack_seqadj.h>
-#include <net/netfilter/nf_conntrack_synproxy.h>
-#include <net/netfilter/nf_conntrack_ecache.h>
-
-static struct iphdr *
-synproxy_build_ip(struct net *net, struct sk_buff *skb, __be32 saddr,
-		  __be32 daddr)
-{
-	struct iphdr *iph;
-
-	skb_reset_network_header(skb);
-	iph = skb_put(skb, sizeof(*iph));
-	iph->version	= 4;
-	iph->ihl	= sizeof(*iph) / 4;
-	iph->tos	= 0;
-	iph->id		= 0;
-	iph->frag_off	= htons(IP_DF);
-	iph->ttl	= net->ipv4.sysctl_ip_default_ttl;
-	iph->protocol	= IPPROTO_TCP;
-	iph->check	= 0;
-	iph->saddr	= saddr;
-	iph->daddr	= daddr;
-
-	return iph;
-}
-
-static void
-synproxy_send_tcp(struct net *net,
-		  const struct sk_buff *skb, struct sk_buff *nskb,
-		  struct nf_conntrack *nfct, enum ip_conntrack_info ctinfo,
-		  struct iphdr *niph, struct tcphdr *nth,
-		  unsigned int tcp_hdr_size)
-{
-	nth->check = ~tcp_v4_check(tcp_hdr_size, niph->saddr, niph->daddr, 0);
-	nskb->ip_summed   = CHECKSUM_PARTIAL;
-	nskb->csum_start  = (unsigned char *)nth - nskb->head;
-	nskb->csum_offset = offsetof(struct tcphdr, check);
-
-	skb_dst_set_noref(nskb, skb_dst(skb));
-	nskb->protocol = htons(ETH_P_IP);
-	if (ip_route_me_harder(net, nskb, RTN_UNSPEC))
-		goto free_nskb;
-
-	if (nfct) {
-		nf_ct_set(nskb, (struct nf_conn *)nfct, ctinfo);
-		nf_conntrack_get(nfct);
-	}
-
-	ip_local_out(net, nskb->sk, nskb);
-	return;
-
-free_nskb:
-	kfree_skb(nskb);
-}
-
-static void
-synproxy_send_client_synack(struct net *net,
-			    const struct sk_buff *skb, const struct tcphdr *th,
-			    const struct synproxy_options *opts)
-{
-	struct sk_buff *nskb;
-	struct iphdr *iph, *niph;
-	struct tcphdr *nth;
-	unsigned int tcp_hdr_size;
-	u16 mss = opts->mss;
-
-	iph = ip_hdr(skb);
-
-	tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts);
-	nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER,
-			 GFP_ATOMIC);
-	if (nskb == NULL)
-		return;
-	skb_reserve(nskb, MAX_TCP_HEADER);
-
-	niph = synproxy_build_ip(net, nskb, iph->daddr, iph->saddr);
-
-	skb_reset_transport_header(nskb);
-	nth = skb_put(nskb, tcp_hdr_size);
-	nth->source	= th->dest;
-	nth->dest	= th->source;
-	nth->seq	= htonl(__cookie_v4_init_sequence(iph, th, &mss));
-	nth->ack_seq	= htonl(ntohl(th->seq) + 1);
-	tcp_flag_word(nth) = TCP_FLAG_SYN | TCP_FLAG_ACK;
-	if (opts->options & XT_SYNPROXY_OPT_ECN)
-		tcp_flag_word(nth) |= TCP_FLAG_ECE;
-	nth->doff	= tcp_hdr_size / 4;
-	nth->window	= 0;
-	nth->check	= 0;
-	nth->urg_ptr	= 0;
-
-	synproxy_build_options(nth, opts);
-
-	synproxy_send_tcp(net, skb, nskb, skb_nfct(skb),
-			  IP_CT_ESTABLISHED_REPLY, niph, nth, tcp_hdr_size);
-}
-
-static void
-synproxy_send_server_syn(struct net *net,
-			 const struct sk_buff *skb, const struct tcphdr *th,
-			 const struct synproxy_options *opts, u32 recv_seq)
-{
-	struct synproxy_net *snet = synproxy_pernet(net);
-	struct sk_buff *nskb;
-	struct iphdr *iph, *niph;
-	struct tcphdr *nth;
-	unsigned int tcp_hdr_size;
-
-	iph = ip_hdr(skb);
-
-	tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts);
-	nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER,
-			 GFP_ATOMIC);
-	if (nskb == NULL)
-		return;
-	skb_reserve(nskb, MAX_TCP_HEADER);
-
-	niph = synproxy_build_ip(net, nskb, iph->saddr, iph->daddr);
-
-	skb_reset_transport_header(nskb);
-	nth = skb_put(nskb, tcp_hdr_size);
-	nth->source	= th->source;
-	nth->dest	= th->dest;
-	nth->seq	= htonl(recv_seq - 1);
-	/* ack_seq is used to relay our ISN to the synproxy hook to initialize
-	 * sequence number translation once a connection tracking entry exists.
-	 */
-	nth->ack_seq	= htonl(ntohl(th->ack_seq) - 1);
-	tcp_flag_word(nth) = TCP_FLAG_SYN;
-	if (opts->options & XT_SYNPROXY_OPT_ECN)
-		tcp_flag_word(nth) |= TCP_FLAG_ECE | TCP_FLAG_CWR;
-	nth->doff	= tcp_hdr_size / 4;
-	nth->window	= th->window;
-	nth->check	= 0;
-	nth->urg_ptr	= 0;
-
-	synproxy_build_options(nth, opts);
-
-	synproxy_send_tcp(net, skb, nskb, &snet->tmpl->ct_general, IP_CT_NEW,
-			  niph, nth, tcp_hdr_size);
-}
-
-static void
-synproxy_send_server_ack(struct net *net,
-			 const struct ip_ct_tcp *state,
-			 const struct sk_buff *skb, const struct tcphdr *th,
-			 const struct synproxy_options *opts)
-{
-	struct sk_buff *nskb;
-	struct iphdr *iph, *niph;
-	struct tcphdr *nth;
-	unsigned int tcp_hdr_size;
-
-	iph = ip_hdr(skb);
-
-	tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts);
-	nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER,
-			 GFP_ATOMIC);
-	if (nskb == NULL)
-		return;
-	skb_reserve(nskb, MAX_TCP_HEADER);
-
-	niph = synproxy_build_ip(net, nskb, iph->daddr, iph->saddr);
 
-	skb_reset_transport_header(nskb);
-	nth = skb_put(nskb, tcp_hdr_size);
-	nth->source	= th->dest;
-	nth->dest	= th->source;
-	nth->seq	= htonl(ntohl(th->ack_seq));
-	nth->ack_seq	= htonl(ntohl(th->seq) + 1);
-	tcp_flag_word(nth) = TCP_FLAG_ACK;
-	nth->doff	= tcp_hdr_size / 4;
-	nth->window	= htons(state->seen[IP_CT_DIR_ORIGINAL].td_maxwin);
-	nth->check	= 0;
-	nth->urg_ptr	= 0;
-
-	synproxy_build_options(nth, opts);
-
-	synproxy_send_tcp(net, skb, nskb, NULL, 0, niph, nth, tcp_hdr_size);
-}
-
-static void
-synproxy_send_client_ack(struct net *net,
-			 const struct sk_buff *skb, const struct tcphdr *th,
-			 const struct synproxy_options *opts)
-{
-	struct sk_buff *nskb;
-	struct iphdr *iph, *niph;
-	struct tcphdr *nth;
-	unsigned int tcp_hdr_size;
-
-	iph = ip_hdr(skb);
-
-	tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts);
-	nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER,
-			 GFP_ATOMIC);
-	if (nskb == NULL)
-		return;
-	skb_reserve(nskb, MAX_TCP_HEADER);
-
-	niph = synproxy_build_ip(net, nskb, iph->saddr, iph->daddr);
-
-	skb_reset_transport_header(nskb);
-	nth = skb_put(nskb, tcp_hdr_size);
-	nth->source	= th->source;
-	nth->dest	= th->dest;
-	nth->seq	= htonl(ntohl(th->seq) + 1);
-	nth->ack_seq	= th->ack_seq;
-	tcp_flag_word(nth) = TCP_FLAG_ACK;
-	nth->doff	= tcp_hdr_size / 4;
-	nth->window	= htons(ntohs(th->window) >> opts->wscale);
-	nth->check	= 0;
-	nth->urg_ptr	= 0;
-
-	synproxy_build_options(nth, opts);
-
-	synproxy_send_tcp(net, skb, nskb, skb_nfct(skb),
-			  IP_CT_ESTABLISHED_REPLY, niph, nth, tcp_hdr_size);
-}
-
-static bool
-synproxy_recv_client_ack(struct net *net,
-			 const struct sk_buff *skb, const struct tcphdr *th,
-			 struct synproxy_options *opts, u32 recv_seq)
-{
-	struct synproxy_net *snet = synproxy_pernet(net);
-	int mss;
-
-	mss = __cookie_v4_check(ip_hdr(skb), th, ntohl(th->ack_seq) - 1);
-	if (mss == 0) {
-		this_cpu_inc(snet->stats->cookie_invalid);
-		return false;
-	}
-
-	this_cpu_inc(snet->stats->cookie_valid);
-	opts->mss = mss;
-	opts->options |= XT_SYNPROXY_OPT_MSS;
-
-	if (opts->options & XT_SYNPROXY_OPT_TIMESTAMP)
-		synproxy_check_timestamp_cookie(opts);
-
-	synproxy_send_server_syn(net, skb, th, opts, recv_seq);
-	return true;
-}
+#include <net/netfilter/nf_synproxy.h>
 
 static unsigned int
 synproxy_tg4(struct sk_buff *skb, const struct xt_action_param *par)
@@ -309,135 +59,6 @@ synproxy_tg4(struct sk_buff *skb, const struct xt_action_param *par)
 	return XT_CONTINUE;
 }
 
-static unsigned int ipv4_synproxy_hook(void *priv,
-				       struct sk_buff *skb,
-				       const struct nf_hook_state *nhs)
-{
-	struct net *net = nhs->net;
-	struct synproxy_net *snet = synproxy_pernet(net);
-	enum ip_conntrack_info ctinfo;
-	struct nf_conn *ct;
-	struct nf_conn_synproxy *synproxy;
-	struct synproxy_options opts = {};
-	const struct ip_ct_tcp *state;
-	struct tcphdr *th, _th;
-	unsigned int thoff;
-
-	ct = nf_ct_get(skb, &ctinfo);
-	if (ct == NULL)
-		return NF_ACCEPT;
-
-	synproxy = nfct_synproxy(ct);
-	if (synproxy == NULL)
-		return NF_ACCEPT;
-
-	if (nf_is_loopback_packet(skb) ||
-	    ip_hdr(skb)->protocol != IPPROTO_TCP)
-		return NF_ACCEPT;
-
-	thoff = ip_hdrlen(skb);
-	th = skb_header_pointer(skb, thoff, sizeof(_th), &_th);
-	if (th == NULL)
-		return NF_DROP;
-
-	state = &ct->proto.tcp;
-	switch (state->state) {
-	case TCP_CONNTRACK_CLOSE:
-		if (th->rst && !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
-			nf_ct_seqadj_init(ct, ctinfo, synproxy->isn -
-						      ntohl(th->seq) + 1);
-			break;
-		}
-
-		if (!th->syn || th->ack ||
-		    CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
-			break;
-
-		/* Reopened connection - reset the sequence number and timestamp
-		 * adjustments, they will get initialized once the connection is
-		 * reestablished.
-		 */
-		nf_ct_seqadj_init(ct, ctinfo, 0);
-		synproxy->tsoff = 0;
-		this_cpu_inc(snet->stats->conn_reopened);
-
-		/* fall through */
-	case TCP_CONNTRACK_SYN_SENT:
-		if (!synproxy_parse_options(skb, thoff, th, &opts))
-			return NF_DROP;
-
-		if (!th->syn && th->ack &&
-		    CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) {
-			/* Keep-Alives are sent with SEG.SEQ = SND.NXT-1,
-			 * therefore we need to add 1 to make the SYN sequence
-			 * number match the one of first SYN.
-			 */
-			if (synproxy_recv_client_ack(net, skb, th, &opts,
-						     ntohl(th->seq) + 1)) {
-				this_cpu_inc(snet->stats->cookie_retrans);
-				consume_skb(skb);
-				return NF_STOLEN;
-			} else {
-				return NF_DROP;
-			}
-		}
-
-		synproxy->isn = ntohl(th->ack_seq);
-		if (opts.options & XT_SYNPROXY_OPT_TIMESTAMP)
-			synproxy->its = opts.tsecr;
-
-		nf_conntrack_event_cache(IPCT_SYNPROXY, ct);
-		break;
-	case TCP_CONNTRACK_SYN_RECV:
-		if (!th->syn || !th->ack)
-			break;
-
-		if (!synproxy_parse_options(skb, thoff, th, &opts))
-			return NF_DROP;
-
-		if (opts.options & XT_SYNPROXY_OPT_TIMESTAMP) {
-			synproxy->tsoff = opts.tsval - synproxy->its;
-			nf_conntrack_event_cache(IPCT_SYNPROXY, ct);
-		}
-
-		opts.options &= ~(XT_SYNPROXY_OPT_MSS |
-				  XT_SYNPROXY_OPT_WSCALE |
-				  XT_SYNPROXY_OPT_SACK_PERM);
-
-		swap(opts.tsval, opts.tsecr);
-		synproxy_send_server_ack(net, state, skb, th, &opts);
-
-		nf_ct_seqadj_init(ct, ctinfo, synproxy->isn - ntohl(th->seq));
-		nf_conntrack_event_cache(IPCT_SEQADJ, ct);
-
-		swap(opts.tsval, opts.tsecr);
-		synproxy_send_client_ack(net, skb, th, &opts);
-
-		consume_skb(skb);
-		return NF_STOLEN;
-	default:
-		break;
-	}
-
-	synproxy_tstamp_adjust(skb, thoff, th, ct, ctinfo, synproxy);
-	return NF_ACCEPT;
-}
-
-static const struct nf_hook_ops ipv4_synproxy_ops[] = {
-	{
-		.hook		= ipv4_synproxy_hook,
-		.pf		= NFPROTO_IPV4,
-		.hooknum	= NF_INET_LOCAL_IN,
-		.priority	= NF_IP_PRI_CONNTRACK_CONFIRM - 1,
-	},
-	{
-		.hook		= ipv4_synproxy_hook,
-		.pf		= NFPROTO_IPV4,
-		.hooknum	= NF_INET_POST_ROUTING,
-		.priority	= NF_IP_PRI_CONNTRACK_CONFIRM - 1,
-	},
-};
-
 static int synproxy_tg4_check(const struct xt_tgchk_param *par)
 {
 	struct synproxy_net *snet = synproxy_pernet(par->net);
@@ -452,16 +73,12 @@ static int synproxy_tg4_check(const struct xt_tgchk_param *par)
 	if (err)
 		return err;
 
-	if (snet->hook_ref4 == 0) {
-		err = nf_register_net_hooks(par->net, ipv4_synproxy_ops,
-					    ARRAY_SIZE(ipv4_synproxy_ops));
-		if (err) {
-			nf_ct_netns_put(par->net, par->family);
-			return err;
-		}
+	err = nf_synproxy_ipv4_init(snet, par->net);
+	if (err) {
+		nf_ct_netns_put(par->net, par->family);
+		return err;
 	}
 
-	snet->hook_ref4++;
 	return err;
 }
 
@@ -469,10 +86,7 @@ static void synproxy_tg4_destroy(const struct xt_tgdtor_param *par)
 {
 	struct synproxy_net *snet = synproxy_pernet(par->net);
 
-	snet->hook_ref4--;
-	if (snet->hook_ref4 == 0)
-		nf_unregister_net_hooks(par->net, ipv4_synproxy_ops,
-					ARRAY_SIZE(ipv4_synproxy_ops));
+	nf_synproxy_ipv4_fini(snet, par->net);
 	nf_ct_netns_put(par->net, par->family);
 }
 
diff --git a/net/ipv4/netfilter/ipt_ah.c b/net/ipv4/netfilter/ipt_ah.c
index 7c6c20eaf4db..161ba412cb08 100644
--- a/net/ipv4/netfilter/ipt_ah.c
+++ b/net/ipv4/netfilter/ipt_ah.c
@@ -1,9 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* Kernel module to match AH parameters. */
 /* (C) 1999-2000 Yon Uriarte <yon@astaro.de>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 #include <linux/in.h>
diff --git a/net/ipv4/netfilter/ipt_rpfilter.c b/net/ipv4/netfilter/ipt_rpfilter.c
index 0b10d8812828..59031670b16a 100644
--- a/net/ipv4/netfilter/ipt_rpfilter.c
+++ b/net/ipv4/netfilter/ipt_rpfilter.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2011 Florian Westphal <fw@strlen.de>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  * based on fib_frontend.c; Author: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
diff --git a/net/ipv4/netfilter/iptable_filter.c b/net/ipv4/netfilter/iptable_filter.c
index 9ac92ea7b93c..9d54b4017e50 100644
--- a/net/ipv4/netfilter/iptable_filter.c
+++ b/net/ipv4/netfilter/iptable_filter.c
@@ -1,13 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
  *
  * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  */
 
 #include <linux/module.h>
diff --git a/net/ipv4/netfilter/iptable_mangle.c b/net/ipv4/netfilter/iptable_mangle.c
index dea138ca8925..bb9266ea3785 100644
--- a/net/ipv4/netfilter/iptable_mangle.c
+++ b/net/ipv4/netfilter/iptable_mangle.c
@@ -1,12 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
  *
  * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 #include <linux/module.h>
 #include <linux/netfilter_ipv4/ip_tables.h>
diff --git a/net/ipv4/netfilter/iptable_nat.c b/net/ipv4/netfilter/iptable_nat.c
index 007da0882412..ad33687b7444 100644
--- a/net/ipv4/netfilter/iptable_nat.c
+++ b/net/ipv4/netfilter/iptable_nat.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* (C) 1999-2001 Paul `Rusty' Russell
  * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
  * (C) 2011 Patrick McHardy <kaber@trash.net>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 
 #include <linux/module.h>
diff --git a/net/ipv4/netfilter/iptable_raw.c b/net/ipv4/netfilter/iptable_raw.c
index 6eefde5bc468..69697eb4bfc6 100644
--- a/net/ipv4/netfilter/iptable_raw.c
+++ b/net/ipv4/netfilter/iptable_raw.c
@@ -2,7 +2,7 @@
 /*
  * 'raw' table, which is the very first hooked in at PRE_ROUTING and LOCAL_OUT .
  *
- * Copyright (C) 2003 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
+ * Copyright (C) 2003 Jozsef Kadlecsik <kadlec@netfilter.org>
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 #include <linux/module.h>
diff --git a/net/ipv4/netfilter/iptable_security.c b/net/ipv4/netfilter/iptable_security.c
index e5379fe57b64..ac633c1db97e 100644
--- a/net/ipv4/netfilter/iptable_security.c
+++ b/net/ipv4/netfilter/iptable_security.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * "security" table
  *
@@ -10,10 +11,6 @@
  * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  * Copyright (C) 2000-2004 Netfilter Core Team <coreteam <at> netfilter.org>
  * Copyright (C) 2008 Red Hat, Inc., James Morris <jmorris <at> redhat.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 #include <linux/module.h>
 #include <linux/netfilter_ipv4/ip_tables.h>
diff --git a/net/ipv4/netfilter/nf_defrag_ipv4.c b/net/ipv4/netfilter/nf_defrag_ipv4.c
index a0d3ad60a411..8115611aa47d 100644
--- a/net/ipv4/netfilter/nf_defrag_ipv4.c
+++ b/net/ipv4/netfilter/nf_defrag_ipv4.c
@@ -1,9 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* (C) 1999-2001 Paul `Rusty' Russell
  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 
 #include <linux/types.h>
diff --git a/net/ipv4/netfilter/nf_log_arp.c b/net/ipv4/netfilter/nf_log_arp.c
index df5c2a2061a4..7a83f881efa9 100644
--- a/net/ipv4/netfilter/nf_log_arp.c
+++ b/net/ipv4/netfilter/nf_log_arp.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * (C) 2014 by Pablo Neira Ayuso <pablo@netfilter.org>
  *
@@ -5,10 +6,6 @@
  *
  * Bart De Schuymer <bdschuym@pandora.be>
  * Harald Welte <laforge@netfilter.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
diff --git a/net/ipv4/netfilter/nf_log_ipv4.c b/net/ipv4/netfilter/nf_log_ipv4.c
index 1e6f28c97d3a..4b2d49cc9f1a 100644
--- a/net/ipv4/netfilter/nf_log_ipv4.c
+++ b/net/ipv4/netfilter/nf_log_ipv4.c
@@ -1,9 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* (C) 1999-2001 Paul `Rusty' Russell
  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
diff --git a/net/ipv4/netfilter/nf_nat_h323.c b/net/ipv4/netfilter/nf_nat_h323.c
index 15f2b2604890..87b711fd5a44 100644
--- a/net/ipv4/netfilter/nf_nat_h323.c
+++ b/net/ipv4/netfilter/nf_nat_h323.c
@@ -1,13 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * H.323 extension for NAT alteration.
  *
  * Copyright (c) 2006 Jing Min Zhao <zhaojingmin@users.sourceforge.net>
  * Copyright (c) 2006-2012 Patrick McHardy <kaber@trash.net>
  *
- * This source code is licensed under General Public License version 2.
- *
  * Based on the 'brute force' H.323 NAT module by
- * Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
+ * Jozsef Kadlecsik <kadlec@netfilter.org>
  */
 
 #include <linux/module.h>
diff --git a/net/ipv4/netfilter/nf_reject_ipv4.c b/net/ipv4/netfilter/nf_reject_ipv4.c
index 7dc3c324b911..2361fdac2c43 100644
--- a/net/ipv4/netfilter/nf_reject_ipv4.c
+++ b/net/ipv4/netfilter/nf_reject_ipv4.c
@@ -1,9 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* (C) 1999-2001 Paul `Rusty' Russell
  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 
 #include <linux/module.h>
diff --git a/net/ipv4/netfilter/nf_socket_ipv4.c b/net/ipv4/netfilter/nf_socket_ipv4.c
index 4824b1e183a1..36a28d46149c 100644
--- a/net/ipv4/netfilter/nf_socket_ipv4.c
+++ b/net/ipv4/netfilter/nf_socket_ipv4.c
@@ -1,11 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2007-2008 BalaBit IT Ltd.
  * Author: Krisztian Kovacs
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 #include <linux/module.h>
diff --git a/net/ipv4/netfilter/nf_tproxy_ipv4.c b/net/ipv4/netfilter/nf_tproxy_ipv4.c
index 40c93b3bd731..b2bae0b0e42a 100644
--- a/net/ipv4/netfilter/nf_tproxy_ipv4.c
+++ b/net/ipv4/netfilter/nf_tproxy_ipv4.c
@@ -1,11 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2007-2008 BalaBit IT Ltd.
  * Author: Krisztian Kovacs
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  */
 
 #include <net/netfilter/nf_tproxy.h>
diff --git a/net/ipv4/netfilter/nft_dup_ipv4.c b/net/ipv4/netfilter/nft_dup_ipv4.c
index 0af3d8df70dd..abf89b972094 100644
--- a/net/ipv4/netfilter/nft_dup_ipv4.c
+++ b/net/ipv4/netfilter/nft_dup_ipv4.c
@@ -1,9 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
  */
 
 #include <linux/kernel.h>
diff --git a/net/ipv4/netfilter/nft_fib_ipv4.c b/net/ipv4/netfilter/nft_fib_ipv4.c
index c8888e52591f..ce294113dbcd 100644
--- a/net/ipv4/netfilter/nft_fib_ipv4.c
+++ b/net/ipv4/netfilter/nft_fib_ipv4.c
@@ -1,8 +1,4 @@
-/*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
+// SPDX-License-Identifier: GPL-2.0-only
 
 #include <linux/kernel.h>
 #include <linux/init.h>
diff --git a/net/ipv4/netfilter/nft_reject_ipv4.c b/net/ipv4/netfilter/nft_reject_ipv4.c
index 517ce93699de..7e6fd5cde50f 100644
--- a/net/ipv4/netfilter/nft_reject_ipv4.c
+++ b/net/ipv4/netfilter/nft_reject_ipv4.c
@@ -1,11 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
  * Copyright (c) 2013 Eric Leblond <eric@regit.org>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  * Development of this code funded by Astaro AG (http://www.astaro.com/)
  */