Merge branch 'mptcp-miscellaneous-cleanup'

Mat Martineau says:

====================
mptcp: Miscellaneous cleanup

Here are some cleanup patches we've collected in the MPTCP tree.

Patches 1-4 do some general tidying.

Patch 5 adds an explicit check at netlink command parsing time to
require a port number when the 'signal' flag is set, to catch the error
earlier.

Patches 6 & 7 fix up the MPTCP 'enabled' sysctl, enforcing it as a
boolean value, and ensuring that the !CONFIG_SYSCTL build still works
after the boolean change.
====================

Link: https://lore.kernel.org/r/20210527235430.183465-1-mathew.j.martineau@linux.intel.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/networking/mptcp-sysctl.rst

@@ -7,13 +7,13 @@ MPTCP Sysfs variables
 /proc/sys/net/mptcp/* Variables
 ===============================
 
-enabled - INTEGER
+enabled - BOOLEAN
 	Control whether MPTCP sockets can be created.
 
-	MPTCP sockets can be created if the value is nonzero. This is
-	a per-namespace sysctl.
+	MPTCP sockets can be created if the value is 1. This is a
+	per-namespace sysctl.
 
-	Default: 1
+	Default: 1 (enabled)
 
 add_addr_timeout - INTEGER (seconds)
 	Set the timeout after which an ADD_ADDR control message will be

net/mptcp/ctrl.c

@@ -4,7 +4,9 @@
  * Copyright (c) 2019, Tessares SA.
  */
 
+#ifdef CONFIG_SYSCTL
 #include <linux/sysctl.h>
+#endif
 
 #include <net/net_namespace.h>
 #include <net/netns/generic.h>
@@ -15,9 +17,11 @@
 
 static int mptcp_pernet_id;
 struct mptcp_pernet {
+#ifdef CONFIG_SYSCTL
 	struct ctl_table_header *ctl_table_hdr;
+#endif
 
-	int mptcp_enabled;
+	u8 mptcp_enabled;
 	unsigned int add_addr_timeout;
 };
 
@@ -36,15 +40,24 @@ unsigned int mptcp_get_add_addr_timeout(struct net *net)
 	return mptcp_get_pernet(net)->add_addr_timeout;
 }
 
+static void mptcp_pernet_set_defaults(struct mptcp_pernet *pernet)
+{
+	pernet->mptcp_enabled = 1;
+	pernet->add_addr_timeout = TCP_RTO_MAX;
+}
+
+#ifdef CONFIG_SYSCTL
 static struct ctl_table mptcp_sysctl_table[] = {
 	{
 		.procname = "enabled",
-		.maxlen = sizeof(int),
+		.maxlen = sizeof(u8),
 		.mode = 0644,
 		/* users with CAP_NET_ADMIN or root (not and) can change this
 		 * value, same as other sysctl or the 'net' tree.
 		 */
-		.proc_handler = proc_dointvec,
+		.proc_handler = proc_dou8vec_minmax,
+		.extra1       = SYSCTL_ZERO,
+		.extra2       = SYSCTL_ONE
 	},
 	{
 		.procname = "add_addr_timeout",
@@ -55,12 +68,6 @@ static struct ctl_table mptcp_sysctl_table[] = {
 	{}
 };
 
-static void mptcp_pernet_set_defaults(struct mptcp_pernet *pernet)
-{
-	pernet->mptcp_enabled = 1;
-	pernet->add_addr_timeout = TCP_RTO_MAX;
-}
-
 static int mptcp_pernet_new_table(struct net *net, struct mptcp_pernet *pernet)
 {
 	struct ctl_table_header *hdr;
@@ -100,6 +107,17 @@ static void mptcp_pernet_del_table(struct mptcp_pernet *pernet)
 	kfree(table);
 }
 
+#else
+
+static int mptcp_pernet_new_table(struct net *net, struct mptcp_pernet *pernet)
+{
+	return 0;
+}
+
+static void mptcp_pernet_del_table(struct mptcp_pernet *pernet) {}
+
+#endif /* CONFIG_SYSCTL */
+
 static int __net_init mptcp_net_init(struct net *net)
 {
 	struct mptcp_pernet *pernet = mptcp_get_pernet(net);

net/mptcp/pm_netlink.c

@@ -971,8 +971,14 @@ static int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
 	if (tb[MPTCP_PM_ADDR_ATTR_FLAGS])
 		entry->flags = nla_get_u32(tb[MPTCP_PM_ADDR_ATTR_FLAGS]);
 
-	if (tb[MPTCP_PM_ADDR_ATTR_PORT])
+	if (tb[MPTCP_PM_ADDR_ATTR_PORT]) {
+		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
+			NL_SET_ERR_MSG_ATTR(info->extack, attr,
+					    "flags must have signal when using port");
+			return -EINVAL;
+		}
 		entry->addr.port = htons(nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_PORT]));
+	}
 
 	return 0;
 }
@@ -1913,10 +1919,13 @@ static int __net_init pm_nl_init_net(struct net *net)
 	struct pm_nl_pernet *pernet = net_generic(net, pm_nl_pernet_id);
 
 	INIT_LIST_HEAD_RCU(&pernet->local_addr_list);
-	__reset_counters(pernet);
 	pernet->next_id = 1;
-	bitmap_zero(pernet->id_bitmap, MAX_ADDR_ID + 1);
 	spin_lock_init(&pernet->lock);
+
+	/* No need to initialize other pernet fields, the struct is zeroed at
+	 * allocation time.
+	 */
+
 	return 0;
 }
 

net/mptcp/protocol.h

@@ -627,6 +627,8 @@ static inline void mptcp_write_space(struct sock *sk)
 
 void mptcp_destroy_common(struct mptcp_sock *msk);
 
+#define MPTCP_TOKEN_MAX_RETRIES	4
+
 void __init mptcp_token_init(void);
 static inline void mptcp_token_init_request(struct request_sock *req)
 {

net/mptcp/subflow.c

@@ -162,7 +162,7 @@ static int subflow_check_req(struct request_sock *req,
 	}
 
 	if (mp_opt.mp_capable && listener->request_mptcp) {
-		int err, retries = 4;
+		int err, retries = MPTCP_TOKEN_MAX_RETRIES;
 
 		subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq;
 again:
@@ -430,15 +430,15 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
 			goto do_reset;
 		}
 
+		if (!mptcp_finish_join(sk))
+			goto do_reset;
+
 		subflow_generate_hmac(subflow->local_key, subflow->remote_key,
 				      subflow->local_nonce,
 				      subflow->remote_nonce,
 				      hmac);
 		memcpy(subflow->hmac, hmac, MPTCPOPT_HMAC_LEN);
 
-		if (!mptcp_finish_join(sk))
-			goto do_reset;
-
 		subflow->mp_join = 1;
 		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKRX);
 

net/mptcp/token.c

@@ -33,7 +33,6 @@
 #include <net/mptcp.h>
 #include "protocol.h"
 
-#define TOKEN_MAX_RETRIES	4
 #define TOKEN_MAX_CHAIN_LEN	4
 
 struct token_bucket {
@@ -153,12 +152,9 @@ int mptcp_token_new_connect(struct sock *sk)
 {
 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
-	int retries = TOKEN_MAX_RETRIES;
+	int retries = MPTCP_TOKEN_MAX_RETRIES;
 	struct token_bucket *bucket;
 
-	pr_debug("ssk=%p, local_key=%llu, token=%u, idsn=%llu\n",
-		 sk, subflow->local_key, subflow->token, subflow->idsn);
-
 again:
 	mptcp_crypto_key_gen_sha(&subflow->local_key, &subflow->token,
 				 &subflow->idsn);
@@ -172,6 +168,9 @@ int mptcp_token_new_connect(struct sock *sk)
 		goto again;
 	}
 
+	pr_debug("ssk=%p, local_key=%llu, token=%u, idsn=%llu\n",
+		 sk, subflow->local_key, subflow->token, subflow->idsn);
+
 	WRITE_ONCE(msk->token, subflow->token);
 	__sk_nulls_add_node_rcu((struct sock *)msk, &bucket->msk_chain);
 	bucket->chain_len++;