path: root/net/mptcp/pm.c

// SPDX-License-Identifier: GPL-2.0
/* Multipath TCP
 *
 * Copyright (c) 2019, Intel Corporation.
 */
#define pr_fmt(fmt) "MPTCP: " fmt

#include <linux/rculist.h>
#include <linux/spinlock.h>
#include "protocol.h"
#include "mib.h"

#define ADD_ADDR_RETRANS_MAX	3

struct mptcp_pm_add_entry {
	struct list_head	list;
	struct mptcp_addr_info	addr;
	u8			retrans_times;
	struct timer_list	add_timer;
	struct mptcp_sock	*sock;
};

static DEFINE_SPINLOCK(mptcp_pm_list_lock);
static LIST_HEAD(mptcp_pm_list);

/* path manager helpers */

/* if sk is ipv4 or ipv6_only allows only same-family local and remote addresses,
 * otherwise allow any matching local/remote pair
 */
bool mptcp_pm_addr_families_match(const struct sock *sk,
				  const struct mptcp_addr_info *loc,
				  const struct mptcp_addr_info *rem)
{
	bool mptcp_is_v4 = sk->sk_family == AF_INET;

#if IS_ENABLED(CONFIG_MPTCP_IPV6)
	bool loc_is_v4 = loc->family == AF_INET || ipv6_addr_v4mapped(&loc->addr6);
	bool rem_is_v4 = rem->family == AF_INET || ipv6_addr_v4mapped(&rem->addr6);

	if (mptcp_is_v4)
		return loc_is_v4 && rem_is_v4;

	if (ipv6_only_sock(sk))
		return !loc_is_v4 && !rem_is_v4;

	return loc_is_v4 == rem_is_v4;
#else
	return mptcp_is_v4 && loc->family == AF_INET && rem->family == AF_INET;
#endif
}

bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
			   const struct mptcp_addr_info *b, bool use_port)
{
	bool addr_equals = false;

	if (a->family == b->family) {
		if (a->family == AF_INET)
			addr_equals = a->addr.s_addr == b->addr.s_addr;
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
		else
			addr_equals = ipv6_addr_equal(&a->addr6, &b->addr6);
	} else if (a->family == AF_INET) {
		if (ipv6_addr_v4mapped(&b->addr6))
			addr_equals = a->addr.s_addr == b->addr6.s6_addr32[3];
	} else if (b->family == AF_INET) {
		if (ipv6_addr_v4mapped(&a->addr6))
			addr_equals = a->addr6.s6_addr32[3] == b->addr.s_addr;
#endif
	}

	if (!addr_equals)
		return false;
	if (!use_port)
		return true;

	return a->port == b->port;
}

void mptcp_local_address(const struct sock_common *skc,
			 struct mptcp_addr_info *addr)
{
	addr->family = skc->skc_family;
	addr->port = htons(skc->skc_num);
	if (addr->family == AF_INET)
		addr->addr.s_addr = skc->skc_rcv_saddr;
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
	else if (addr->family == AF_INET6)
		addr->addr6 = skc->skc_v6_rcv_saddr;
#endif
}

void mptcp_remote_address(const struct sock_common *skc,
			  struct mptcp_addr_info *addr)
{
	addr->family = skc->skc_family;
	addr->port = skc->skc_dport;
	if (addr->family == AF_INET)
		addr->addr.s_addr = skc->skc_daddr;
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
	else if (addr->family == AF_INET6)
		addr->addr6 = skc->skc_v6_daddr;
#endif
}

static bool mptcp_pm_is_init_remote_addr(struct mptcp_sock *msk,
					 const struct mptcp_addr_info *remote)
{
	struct mptcp_addr_info mpc_remote;

	mptcp_remote_address((struct sock_common *)msk, &mpc_remote);
	return mptcp_addresses_equal(&mpc_remote, remote, remote->port);
}

bool mptcp_lookup_subflow_by_saddr(const struct list_head *list,
				   const struct mptcp_addr_info *saddr)
{
	struct mptcp_subflow_context *subflow;
	struct mptcp_addr_info cur;
	struct sock_common *skc;

	list_for_each_entry(subflow, list, node) {
		skc = (struct sock_common *)mptcp_subflow_tcp_sock(subflow);

		mptcp_local_address(skc, &cur);
		if (mptcp_addresses_equal(&cur, saddr, saddr->port))
			return true;
	}

	return false;
}

static struct mptcp_pm_add_entry *
mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
				const struct mptcp_addr_info *addr)
{
	struct mptcp_pm_add_entry *entry;

	lockdep_assert_held(&msk->pm.lock);

	list_for_each_entry(entry, &msk->pm.anno_list, list) {
		if (mptcp_addresses_equal(&entry->addr, addr, true))
			return entry;
	}

	return NULL;
}

bool