Merge branch 'ip-sysctl-namespaceify'

Nikolay Borisov says:

====================
Namespacify various ip sysctl knobs

This series continues namespacifying more net related knobs.
The focus here is on ip options. Patches 1,3,4,5 namespacify
the respective sysctl knobs. Patch 2 moves some igmp code to the
correct file (and function) and also adds some #ifdef guards to
silence compilation warnings.

Finally, patch 5 exposes the ip fragmentation related sysctls
since all of the knobs are namespaced.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/inet_frag.h

@@ -13,6 +13,7 @@ struct netns_frags {
 	int			timeout;
 	int			high_thresh;
 	int			low_thresh;
+	int			max_dist;
 };
 
 /**

include/net/ip.h

@@ -245,12 +245,6 @@ extern int inet_peer_threshold;
 extern int inet_peer_minttl;
 extern int inet_peer_maxttl;
 
-/* From ip_input.c */
-extern int sysctl_ip_early_demux;
-
-/* From ip_output.c */
-extern int sysctl_ip_dynaddr;
-
 void ipfrag_init(void);
 
 void ip_static_sysctl_init(void);

include/net/netns/ipv4.h

@@ -80,9 +80,13 @@ struct netns_ipv4 {
 	int sysctl_tcp_ecn;
 	int sysctl_tcp_ecn_fallback;
 
+	int sysctl_ip_default_ttl;
 	int sysctl_ip_no_pmtu_disc;
 	int sysctl_ip_fwd_use_pmtu;
 	int sysctl_ip_nonlocal_bind;
+	/* Shall we try to damage output packets if routing dev changes? */
+	int sysctl_ip_dynaddr;
+	int sysctl_ip_early_demux;
 
 	int sysctl_fwmark_reflect;
 	int sysctl_tcp_fwmark_accept;

include/net/route.h

@@ -329,14 +329,13 @@ static inline int inet_iif(const struct sk_buff *skb)
 	return skb->skb_iif;
 }
 
-extern int sysctl_ip_default_ttl;
-
 static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
 {
 	int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
+	struct net *net = dev_net(dst->dev);
 
 	if (hoplimit == 0)
-		hoplimit = sysctl_ip_default_ttl;
+		hoplimit = net->ipv4.sysctl_ip_default_ttl;
 	return hoplimit;
 }
 

net/bridge/netfilter/nft_reject_bridge.c

@@ -48,6 +48,7 @@ static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb,
 	struct iphdr *niph;
 	const struct tcphdr *oth;
 	struct tcphdr _oth;
+	struct net *net = sock_net(oldskb->sk);
 
 	if (!nft_bridge_iphdr_validate(oldskb))
 		return;
@@ -63,9 +64,9 @@ static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb,
 
 	skb_reserve(nskb, LL_MAX_HEADER);
 	niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_TCP,
-				   sysctl_ip_default_ttl);
+				   net->ipv4.sysctl_ip_default_ttl);
 	nf_reject_ip_tcphdr_put(nskb, oldskb, oth);
-	niph->ttl	= sysctl_ip_default_ttl;
+	niph->ttl	= net->ipv4.sysctl_ip_default_ttl;
 	niph->tot_len	= htons(nskb->len);
 	ip_send_check(niph);
 
@@ -85,6 +86,7 @@ static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb,
 	void *payload;
 	__wsum csum;
 	u8 proto;
+	struct net *net = sock_net(oldskb->sk);
 
 	if (oldskb->csum_bad || !nft_bridge_iphdr_validate(oldskb))
 		return;
@@ -119,7 +121,7 @@ static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb,
 
 	skb_reserve(nskb, LL_MAX_HEADER);
 	niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_ICMP,
-				   sysctl_ip_default_ttl);
+				   net->ipv4.sysctl_ip_default_ttl);
 
 	skb_reset_transport_header(nskb);
 	icmph = (struct icmphdr *)skb_put(nskb, sizeof(struct icmphdr));

net/ipv4/af_inet.c

@@ -1095,12 +1095,6 @@ void inet_unregister_protosw(struct inet_protosw *p)
 }
 EXPORT_SYMBOL(inet_unregister_protosw);
 
-/*
- *      Shall we try to damage output packets if routing dev changes?
- */
-
-int sysctl_ip_dynaddr __read_mostly;
-
 static int inet_sk_reselect_saddr(struct sock *sk)
 {
 	struct inet_sock *inet = inet_sk(sk);
@@ -1131,7 +1125,7 @@ static int inet_sk_reselect_saddr(struct sock *sk)
 	if (new_saddr == old_saddr)
 		return 0;
 
-	if (sysctl_ip_dynaddr > 1) {
+	if (sock_net(sk)->ipv4.sysctl_ip_dynaddr > 1) {
 		pr_info("%s(): shifting inet->saddr from %pI4 to %pI4\n",
 			__func__, &old_saddr, &new_saddr);
 	}
@@ -1186,7 +1180,7 @@ int inet_sk_rebuild_header(struct sock *sk)
 		 * Other protocols have to map its equivalent state to TCP_SYN_SENT.
 		 * DCCP maps its DCCP_REQUESTING state to TCP_SYN_SENT. -acme
 		 */
-		if (!sysctl_ip_dynaddr ||
+		if (!sock_net(sk)->ipv4.sysctl_ip_dynaddr ||
 		    sk->sk_state != TCP_SYN_SENT ||
 		    (sk->sk_userlocks & SOCK_BINDADDR_LOCK) ||
 		    (err = inet_sk_reselect_saddr(sk)) != 0)

net/ipv4/igmp.c

@@ -1224,7 +1224,9 @@ static void igmp_group_dropped(struct ip_mc_list *im)
 static void igmp_group_added(struct ip_mc_list *im)
 {
 	struct in_device *in_dev = im->interface;
+#ifdef CONFIG_IP_MULTICAST
 	struct net *net = dev_net(in_dev->dev);
+#endif
 
 	if (im->loaded == 0) {
 		im->loaded = 1;
@@ -1316,7 +1318,9 @@ static void ip_mc_hash_remove(struct in_device *in_dev,
 void ip_mc_inc_group(struct in_device *in_dev, __be32 addr)
 {
 	struct ip_mc_list *im;
+#ifdef CONFIG_IP_MULTICAST
 	struct net *net = dev_net(in_dev->dev);
+#endif
 
 	ASSERT_RTNL();
 
@@ -1643,7 +1647,9 @@ void ip_mc_down(struct in_device *in_dev)
 
 void ip_mc_init_dev(struct in_device *in_dev)
 {
+#ifdef CONFIG_IP_MULTICAST
 	struct net *net = dev_net(in_dev->dev);
+#endif
 	ASSERT_RTNL();
 
 #ifdef CONFIG_IP_MULTICAST
@@ -1662,7 +1668,9 @@ void ip_mc_init_dev(struct in_device *in_dev)
 void ip_mc_up(struct in_device *in_dev)
 {
 	struct ip_mc_list *pmc;
+#ifdef CONFIG_IP_MULTICAST
 	struct net *net = dev_net(in_dev->dev);
+#endif
 
 	ASSERT_RTNL();
 
@@ -2923,6 +2931,12 @@ static int __net_init igmp_net_init(struct net *net)
 		goto out_sock;
 	}
 
+	/* Sysctl initialization */
+	net->ipv4.sysctl_igmp_max_memberships = 20;
+	net->ipv4.sysctl_igmp_max_msf = 10;
+	/* IGMP reports for link-local multicast groups are enabled by default */
+	net->ipv4.sysctl_igmp_llm_reports = 1;
+	net->ipv4.sysctl_igmp_qrv = 2;
 	return 0;
 
 out_sock:

net/ipv4/ip_fragment.c

@@ -54,8 +54,6 @@
  * code now. If you change something here, _PLEASE_ update ipv6/reassembly.c
  * as well. Or notify me, at least. --ANK
  */
-
-static int sysctl_ipfrag_max_dist __read_mostly = 64;
 static const char ip_frag_cache_name[] = "ip4-frags";
 
 struct ipfrag_skb_cb
@@ -150,7 +148,7 @@ static void ip4_frag_init(struct inet_frag_queue *q, const void *a)
 	qp->daddr = arg->iph->daddr;
 	qp->vif = arg->vif;
 	qp->user = arg->user;
-	qp->peer = sysctl_ipfrag_max_dist ?
+	qp->peer = q->net->max_dist ?
 		inet_getpeer_v4(net->ipv4.peers, arg->iph->saddr, arg->vif, 1) :
 		NULL;
 }
@@ -275,7 +273,7 @@ static struct ipq *ip_find(struct net *net, struct iphdr *iph,
 static int ip_frag_too_far(struct ipq *qp)
 {
 	struct inet_peer *peer = qp->peer;
-	unsigned int max = sysctl_ipfrag_max_dist;
+	unsigned int max = qp->q.net->max_dist;
 	unsigned int start, end;
 
 	int rc;
@@ -749,6 +747,14 @@ static struct ctl_table ip4_frags_ns_ctl_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_jiffies,
 	},
+	{
+		.procname	= "ipfrag_max_dist",
+		.data		= &init_net.ipv4.frags.max_dist,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &zero
+	},
 	{ }
 };
 
@@ -762,14 +768,6 @@ static struct ctl_table ip4_frags_ctl_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_jiffies,
 	},
-	{
-		.procname	= "ipfrag_max_dist",
-		.data		= &sysctl_ipfrag_max_dist,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero
-	},
 	{ }
 };
 
@@ -790,10 +788,7 @@ static int __net_init ip4_frags_ns_ctl_register(struct net *net)
 		table[1].data = &net->ipv4.frags.low_thresh;
 		table[1].extra2 = &net->ipv4.frags.high_thresh;
 		table[2].data = &net->ipv4.frags.timeout;
-
-		/* Don't export sysctls to unprivileged users */
-		if (net->user_ns != &init_user_ns)
-			table[0].procname = NULL;
+		table[3].data = &net->ipv4.frags.max_dist;
 	}
 
 	hdr = register_net_sysctl(net, "net/ipv4", table);
@@ -865,6 +860,8 @@ static int __net_init ipv4_frags_init_net(struct net *net)
 	 */
 	net->ipv4.frags.timeout = IP_FRAG_TIME;
 
+	net->ipv4.frags.max_dist = 64;
+
 	res = inet_frags_init_net(&net->ipv4.frags);
 	if (res)
 		return res;

net/ipv4/ip_input.c

@@ -308,15 +308,12 @@ static inline bool ip_rcv_options(struct sk_buff *skb)
 	return true;
 }
 
-int sysctl_ip_early_demux __read_mostly = 1;
-EXPORT_SYMBOL(sysctl_ip_early_demux);
-
 static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
 	const struct iphdr *iph = ip_hdr(skb);
 	struct rtable *rt;
 
-	if (sysctl_ip_early_demux &&
+	if (net->ipv4.sysctl_ip_early_demux &&
 	    !skb_dst(skb) &&
 	    !skb->sk &&
 	    !ip_is_fragment(iph)) {

net/ipv4/ip_output.c

@@ -79,9 +79,6 @@
 #include <linux/netlink.h>
 #include <linux/tcp.h>
 
-int sysctl_ip_default_ttl __read_mostly = IPDEFTTL;
-EXPORT_SYMBOL(sysctl_ip_default_ttl);
-
 static int
 ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 	    unsigned int mtu,

net/ipv4/ip_sockglue.c

@@ -1341,10 +1341,13 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname,
 		val = inet->tos;
 		break;
 	case IP_TTL:
+	{
+		struct net *net = sock_net(sk);
 		val = (inet->uc_ttl == -1 ?
-		       sysctl_ip_default_ttl :
+		       net->ipv4.sysctl_ip_default_ttl :
 		       inet->uc_ttl);
 		break;
+	}
 	case IP_HDRINCL:
 		val = inet->hdrincl;
 		break;

net/ipv4/netfilter/ipt_SYNPROXY.c

@@ -21,6 +21,7 @@ static struct iphdr *
 synproxy_build_ip(struct sk_buff *skb, __be32 saddr, __be32 daddr)
 {
 	struct iphdr *iph;
+	struct net *net = sock_net(skb->sk);
 
 	skb_reset_network_header(skb);
 	iph = (struct iphdr *)skb_put(skb, sizeof(*iph));
@@ -29,7 +30,7 @@ synproxy_build_ip(struct sk_buff *skb, __be32 saddr, __be32 daddr)
 	iph->tos	= 0;
 	iph->id		= 0;
 	iph->frag_off	= htons(IP_DF);
-	iph->ttl	= sysctl_ip_default_ttl;
+	iph->ttl	= net->ipv4.sysctl_ip_default_ttl;
 	iph->protocol	= IPPROTO_TCP;
 	iph->check	= 0;
 	iph->saddr	= saddr;

net/ipv4/proc.c

@@ -390,7 +390,7 @@ static int snmp_seq_show(struct seq_file *seq, void *v)
 
 	seq_printf(seq, "\nIp: %d %d",
 		   IPV4_DEVCONF_ALL(net, FORWARDING) ? 1 : 2,
-		   sysctl_ip_default_ttl);
+		   net->ipv4.sysctl_ip_default_ttl);
 
 	BUILD_BUG_ON(offsetof(struct ipstats_mib, mibs) != 0);
 	for (i = 0; snmp4_ipstats_list[i].name != NULL; i++)

net/ipv4/sysctl_net_ipv4.c

@@ -282,15 +282,6 @@ static struct ctl_table ipv4_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec
 	},
-	{
-		.procname	= "ip_default_ttl",
-		.data		= &sysctl_ip_default_ttl,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &ip_ttl_min,
-		.extra2		= &ip_ttl_max,
-	},
 	{
 		.procname	= "tcp_max_orphans",
 		.data		= &sysctl_tcp_max_orphans,
@@ -305,20 +296,6 @@ static struct ctl_table ipv4_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec
 	},
-	{
-		.procname	= "ip_early_demux",
-		.data		= &sysctl_ip_early_demux,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec
-	},
-	{
-		.procname	= "ip_dynaddr",
-		.data		= &sysctl_ip_dynaddr,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec
-	},
 	{
 		.procname	= "tcp_fastopen",
 		.data		= &sysctl_tcp_fastopen,
@@ -752,6 +729,29 @@ static struct ctl_table ipv4_net_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec
 	},
+	{
+		.procname	= "ip_dynaddr",
+		.data		= &init_net.ipv4.sysctl_ip_dynaddr,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec
+	},
+	{
+		.procname	= "ip_early_demux",
+		.data		= &init_net.ipv4.sysctl_ip_early_demux,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec
+	},
+	{
+		.procname	= "ip_default_ttl",
+		.data		= &init_net.ipv4.sysctl_ip_default_ttl,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &ip_ttl_min,
+		.extra2		= &ip_ttl_max,
+	},
 	{
 		.procname	= "ip_local_port_range",
 		.maxlen		= sizeof(init_net.ipv4.ip_local_ports.range),
@@ -988,6 +988,10 @@ static __net_init int ipv4_sysctl_init_net(struct net *net)
 	if (!net->ipv4.sysctl_local_reserved_ports)
 		goto err_ports;
 
+	net->ipv4.sysctl_ip_default_ttl = IPDEFTTL;
+	net->ipv4.sysctl_ip_dynaddr = 0;
+	net->ipv4.sysctl_ip_early_demux = 1;
+
 	return 0;
 
 err_ports:

net/ipv4/tcp_ipv4.c

@@ -2399,12 +2399,6 @@ static int __net_init tcp_sk_init(struct net *net)
 	net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
 	net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
 
-	net->ipv4.sysctl_igmp_max_memberships = 20;
-	net->ipv4.sysctl_igmp_max_msf = 10;
-	/* IGMP reports for link-local multicast groups are enabled by default */
-	net->ipv4.sysctl_igmp_llm_reports = 1;
-	net->ipv4.sysctl_igmp_qrv = 2;
-
 	return 0;
 fail:
 	tcp_sk_exit(net);

net/ipv6/ip6_input.c

@@ -49,7 +49,7 @@
 
 int ip6_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
-	if (sysctl_ip_early_demux && !skb_dst(skb) && skb->sk == NULL) {
+	if (net->ipv4.sysctl_ip_early_demux && !skb_dst(skb) && skb->sk == NULL) {
 		const struct inet6_protocol *ipprot;
 
 		ipprot = rcu_dereference(inet6_protos[ipv6_hdr(skb)->nexthdr]);