blob: c40f1428e6020236db6e13317cde86d7627bce9e [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/* Multipath TCP
*
* Copyright (c) 2021, Red Hat.
*/
#define pr_fmt(fmt) "MPTCP: " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <net/sock.h>
#include <net/protocol.h>
#include <net/tcp.h>
#include <net/mptcp.h>
#include "protocol.h"
#define MIN_INFO_OPTLEN_SIZE 16
#define MIN_FULL_INFO_OPTLEN_SIZE 40
static struct sock *__mptcp_tcp_fallback(struct mptcp_sock *msk)
{
msk_owned_by_me(msk);
if (likely(!__mptcp_check_fallback(msk)))
return NULL;
return msk->first;
}
static u32 sockopt_seq_reset(const struct sock *sk)
{
sock_owned_by_me(sk);
/* Highbits contain state. Allows to distinguish sockopt_seq
* of listener and established:
* s0 = new_listener()
* sockopt(s0) - seq is 1
* s1 = accept(s0) - s1 inherits seq 1 if listener sk (s0)
* sockopt(s0) - seq increments to 2 on s0
* sockopt(s1) // seq increments to 2 on s1 (different option)
* new ssk completes join, inherits options from s0 // seq 2
* Needs sync from mptcp join logic, but ssk->seq == msk->seq
*
* Set High order bits to sk_state so ssk->seq == msk->seq test
* will fail.
*/
return (u32)sk->sk_state << 24u;
}
static void sockopt_seq_inc(struct mptcp_sock *msk)
{
u32 seq = (msk->setsockopt_seq + 1) & 0x00ffffff;
msk->setsockopt_seq = sockopt_seq_reset((struct sock *)msk) + seq;
}
static int mptcp_get_int_option(struct mptcp_sock *msk, sockptr_t optval,
unsigned int optlen, int *val)
{
if (optlen < sizeof(int))
return -EINVAL;
if (copy_from_sockptr(val, optval, sizeof(*val)))
return -EFAULT;
return 0;
}
static void mptcp_sol_socket_sync_intval(struct mptcp_sock *msk, int optname, int val)
{
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
lock_sock(sk);
sockopt_seq_inc(msk);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
bool slow = lock_sock_fast(ssk);
switch (optname) {
case SO_DEBUG:
sock_valbool_flag(ssk, SOCK_DBG, !!val);
break;
case SO_KEEPALIVE:
if (ssk->sk_prot->keepalive)
ssk->sk_prot->keepalive(ssk, !!val);
sock_valbool_flag(ssk, SOCK_KEEPOPEN, !!val);
break;
case SO_PRIORITY:
WRITE_ONCE(ssk->sk_priority, val);
break;
case SO_SNDBUF:
case SO_SNDBUFFORCE:
ssk->sk_userlocks |= SOCK_SNDBUF_LOCK;
WRITE_ONCE(ssk->sk_sndbuf, sk->sk_sndbuf);
mptcp_subflow_ctx(ssk)->cached_sndbuf = sk->sk_sndbuf;
break;
case SO_RCVBUF:
case SO_RCVBUFFORCE:
ssk->sk_userlocks |= SOCK_RCVBUF_LOCK;
WRITE_ONCE(ssk->sk_rcvbuf, sk->sk_rcvbuf);
break;
case SO_MARK:
if (READ_ONCE(ssk->sk_mark) != sk->sk_mark) {
WRITE_ONCE(ssk->sk_mark, sk->sk_mark);
sk_dst_reset(ssk);
}
break;
case SO_INCOMING_CPU:
WRITE_ONCE(ssk->sk_incoming_cpu, val);
break;
}
subflow->setsockopt_seq = msk->setsockopt_seq;
unlock_sock_fast(ssk, slow);
}
release_sock(sk);
}
static int mptcp_sol_socket_intval(struct mptcp_sock *msk, int optname, int val)
{
sockptr_t optval = KERNEL_SOCKPTR(&val);
struct sock *sk = (struct sock *)msk;
int ret;
ret = sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname,
optval, sizeof(val));
if (ret)
return ret;
mptcp_sol_socket_sync_intval(msk, optname, val);
return 0;
}
static void mptcp_so_incoming_cpu(struct mptcp_sock *msk, int val)
{
struct sock *sk = (struct sock *)msk;
WRITE_ONCE(sk->sk_incoming_cpu, val);
mptcp_sol_socket_sync_intval(msk, SO_INCOMING_CPU, val);
}
static int mptcp_setsockopt_sol_socket_tstamp(struct mptcp_sock *msk, int optname, int val)
{
sockptr_t optval = KERNEL_SOCKPTR(&val);
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
int ret;
ret = sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname,
optval, sizeof(val));
if (ret)
return ret;
lock_sock(sk);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
bool slow = lock_sock_fast(ssk);
sock_set_timestamp(sk, optname, !!val);
unlock_sock_fast(ssk, slow);
}
release_sock(sk);
return 0;
}
static int mptcp_setsockopt_sol_socket_int(struct mptcp_sock *msk, int optname,
sockptr_t optval,
unsigned int optlen)
{
int val, ret;
ret = mptcp_get_int_option(msk, optval, optlen, &val);
if (ret)
return ret;
switch (optname) {
case SO_KEEPALIVE:
mptcp_sol_socket_sync_intval(msk, optname, val);
return 0;
case SO_DEBUG:
case SO_MARK:
case SO_PRIORITY:
case SO_SNDBUF:
case SO_SNDBUFFORCE:
case SO_RCVBUF:
case SO_RCVBUFFORCE:
return mptcp_sol_socket_intval(msk, optname, val);
case SO_INCOMING_CPU:
mptcp_so_incoming_cpu(msk, val);
return 0;
case SO_TIMESTAMP_OLD:
case SO_TIMESTAMP_NEW:
case SO_TIMESTAMPNS_OLD:
case SO_TIMESTAMPNS_NEW:
return mptcp_setsockopt_sol_socket_tstamp(msk, optname, val);
}
return -ENOPROTOOPT;
}
static int mptcp_setsockopt_sol_socket_timestamping(struct mptcp_sock *msk,
int optname,
sockptr_t optval,
unsigned int optlen)
{
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
struct so_timestamping timestamping;
int ret;
if (optlen == sizeof(timestamping)) {
if (copy_from_sockptr(&timestamping, optval,
sizeof(timestamping)))
return -EFAULT;
} else if (optlen == sizeof(int)) {
memset(&timestamping, 0, sizeof(timestamping));
if (copy_from_sockptr(&timestamping.flags, optval, sizeof(int)))
return -EFAULT;
} else {
return -EINVAL;
}
ret = sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname,
KERNEL_SOCKPTR(&timestamping),
sizeof(timestamping));
if (ret)
return ret;
lock_sock(sk);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
bool slow = lock_sock_fast(ssk);
sock_set_timestamping(sk, optname, timestamping);
unlock_sock_fast(ssk, slow);
}
release_sock(sk);
return 0;
}
static int mptcp_setsockopt_sol_socket_linger(struct mptcp_sock *msk, sockptr_t optval,
unsigned int optlen)
{
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
struct linger ling;
sockptr_t kopt;
int ret;
if (optlen < sizeof(ling))
return -EINVAL;
if (copy_from_sockptr(&ling, optval, sizeof(ling)))
return -EFAULT;
kopt = KERNEL_SOCKPTR(&ling);
ret = sock_setsockopt(sk->sk_socket, SOL_SOCKET, SO_LINGER, kopt, sizeof(ling));
if (ret)
return ret;
lock_sock(sk);
sockopt_seq_inc(msk);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
bool slow = lock_sock_fast(ssk);
if (!ling.l_onoff) {
sock_reset_flag(ssk, SOCK_LINGER);
} else {
ssk->sk_lingertime = sk->sk_lingertime;
sock_set_flag(ssk, SOCK_LINGER);
}
subflow->setsockopt_seq = msk->setsockopt_seq;
unlock_sock_fast(ssk, slow);
}
release_sock(sk);
return 0;
}
static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,
sockptr_t optval, unsigned int optlen)
{
struct sock *sk = (struct sock *)msk;
struct sock *ssk;
int ret;
switch (optname) {
case SO_REUSEPORT:
case SO_REUSEADDR:
case SO_BINDTODEVICE:
case SO_BINDTOIFINDEX:
lock_sock(sk);
ssk = __mptcp_nmpc_sk(msk);
if (IS_ERR(ssk)) {
release_sock(sk);
return PTR_ERR(ssk);
}
ret = sk_setsockopt(ssk, SOL_SOCKET, optname, optval, optlen);
if (ret == 0) {
if (optname == SO_REUSEPORT)
sk->sk_reuseport = ssk->sk_reuseport;
else if (optname == SO_REUSEADDR)
sk->sk_reuse = ssk->sk_reuse;
else if (optname == SO_BINDTODEVICE)
sk->sk_bound_dev_if = ssk->sk_bound_dev_if;
else if (optname == SO_BINDTOIFINDEX)
sk->sk_bound_dev_if = ssk->sk_bound_dev_if;
}
release_sock(sk);
return ret;
case SO_KEEPALIVE:
case SO_PRIORITY:
case SO_SNDBUF:
case SO_SNDBUFFORCE:
case SO_RCVBUF:
case SO_RCVBUFFORCE:
case SO_MARK:
case SO_INCOMING_CPU:
case SO_DEBUG:
case SO_TIMESTAMP_OLD:
case SO_TIMESTAMP_NEW:
case SO_TIMESTAMPNS_OLD:
case SO_TIMESTAMPNS_NEW:
return mptcp_setsockopt_sol_socket_int(msk, optname, optval,
optlen);
case SO_TIMESTAMPING_OLD:
case SO_TIMESTAMPING_NEW:
return mptcp_setsockopt_sol_socket_timestamping(msk, optname,
optval, optlen);
case SO_LINGER:
return mptcp_setsockopt_sol_socket_linger(msk, optval, optlen);
case SO_RCVLOWAT:
case SO_RCVTIMEO_OLD:
case SO_RCVTIMEO_NEW:
case SO_SNDTIMEO_OLD:
case SO_SNDTIMEO_NEW:
case SO_BUSY_POLL:
case SO_PREFER_BUSY_POLL:
case SO_BUSY_POLL_BUDGET:
/* No need to copy: only relevant for msk */
return sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname, optval, optlen);
case SO_NO_CHECK:
case SO_DONTROUTE:
case SO_BROADCAST:
case SO_BSDCOMPAT:
case SO_PASSCRED:
case SO_PASSPIDFD:
case SO_PASSSEC:
case SO_RXQ_OVFL:
case SO_WIFI_STATUS:
case SO_NOFCS:
case SO_SELECT_ERR_QUEUE:
return 0;
}
/* SO_OOBINLINE is not supported, let's avoid the related mess
* SO_ATTACH_FILTER, SO_ATTACH_BPF, SO_ATTACH_REUSEPORT_CBPF,
* SO_DETACH_REUSEPORT_BPF, SO_DETACH_FILTER, SO_LOCK_FILTER,
* we must be careful with subflows
*
* SO_ATTACH_REUSEPORT_EBPF is not supported, at it checks
* explicitly the sk_protocol field
*
* SO_PEEK_OFF is unsupported, as it is for plain TCP
* SO_MAX_PACING_RATE is unsupported, we must be careful with subflows
* SO_CNX_ADVICE is currently unsupported, could possibly be relevant,
* but likely needs careful design
*
* SO_ZEROCOPY is currently unsupported, TODO in sndmsg
* SO_TXTIME is currently unsupported
*/
return -EOPNOTSUPP;
}
static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname,
sockptr_t optval, unsigned int optlen)
{
struct sock *sk = (struct sock *)msk;
int ret = -EOPNOTSUPP;
struct sock *ssk;
switch (optname) {
case IPV6_V6ONLY:
case IPV6_TRANSPARENT:
case IPV6_FREEBIND:
lock_sock(sk);
ssk = __mptcp_nmpc_sk(msk);
if (IS_ERR(ssk)) {
release_sock(sk);
return PTR_ERR(ssk);
}
ret = tcp_setsockopt(ssk, SOL_IPV6, optname, optval, optlen);
if (ret != 0) {
release_sock(sk);
return ret;
}
sockopt_seq_inc(msk);
switch (optname) {
case IPV6_V6ONLY:
sk->sk_ipv6only = ssk->sk_ipv6only;
break;
case IPV6_TRANSPARENT:
inet_assign_bit(TRANSPARENT, sk,
inet_test_bit(TRANSPARENT, ssk));
break;
case IPV6_FREEBIND:
inet_assign_bit(FREEBIND, sk,
inet_test_bit(FREEBIND, ssk));
break;
}
release_sock(sk);
break;
}
return ret;
}
static bool mptcp_supported_sockopt(int level, int optname)
{
if (level == SOL_IP) {
switch (optname) {
/* should work fine */
case IP_FREEBIND:
case IP_TRANSPARENT:
case IP_BIND_ADDRESS_NO_PORT:
case IP_LOCAL_PORT_RANGE:
/* the following are control cmsg related */
case IP_PKTINFO:
case IP_RECVTTL:
case IP_RECVTOS:
case IP_RECVOPTS:
case IP_RETOPTS:
case IP_PASSSEC:
case IP_RECVORIGDSTADDR:
case IP_CHECKSUM:
case IP_RECVFRAGSIZE:
/* common stuff that need some love */
case IP_TOS:
case IP_TTL:
case IP_MTU_DISCOVER:
case IP_RECVERR:
/* possibly less common may deserve some love */
case IP_MINTTL:
/* the following is apparently a no-op for plain TCP */
case IP_RECVERR_RFC4884:
return true;
}
/* IP_OPTIONS is not supported, needs subflow care */
/* IP_HDRINCL, IP_NODEFRAG are not supported, RAW specific */
/* IP_MULTICAST_TTL, IP_MULTICAST_LOOP, IP_UNICAST_IF,
* IP_ADD_MEMBERSHIP, IP_ADD_SOURCE_MEMBERSHIP, IP_DROP_MEMBERSHIP,
* IP_DROP_SOURCE_MEMBERSHIP, IP_BLOCK_SOURCE, IP_UNBLOCK_SOURCE,
* MCAST_JOIN_GROUP, MCAST_LEAVE_GROUP MCAST_JOIN_SOURCE_GROUP,
* MCAST_LEAVE_SOURCE_GROUP, MCAST_BLOCK_SOURCE, MCAST_UNBLOCK_SOURCE,
* MCAST_MSFILTER, IP_MULTICAST_ALL are not supported, better not deal
* with mcast stuff
*/
/* IP_IPSEC_POLICY, IP_XFRM_POLICY are nut supported, unrelated here */
return false;
}
if (level == SOL_IPV6) {
switch (optname) {
case IPV6_V6ONLY:
/* the following are control cmsg related */
case IPV6_RECVPKTINFO:
case IPV6_2292PKTINFO:
case IPV6_RECVHOPLIMIT:
case IPV6_2292HOPLIMIT:
case IPV6_RECVRTHDR:
case IPV6_2292RTHDR:
case IPV6_RECVHOPOPTS:
case IPV6_2292HOPOPTS:
case IPV6_RECVDSTOPTS:
case IPV6_2292DSTOPTS:
case IPV6_RECVTCLASS:
case IPV6_FLOWINFO:
case IPV6_RECVPATHMTU:
case IPV6_RECVORIGDSTADDR:
case IPV6_RECVFRAGSIZE:
/* the following ones need some love but are quite common */
case IPV6_TCLASS:
case IPV6_TRANSPARENT:
case IPV6_FREEBIND:
case IPV6_PKTINFO:
case IPV6_2292PKTOPTIONS:
case IPV6_UNICAST_HOPS:
case IPV6_MTU_DISCOVER:
case IPV6_MTU:
case IPV6_RECVERR:
case IPV6_FLOWINFO_SEND:
case IPV6_FLOWLABEL_MGR:
case IPV6_MINHOPCOUNT:
case IPV6_DONTFRAG:
case IPV6_AUTOFLOWLABEL:
/* the following one is a no-op for plain TCP */
case IPV6_RECVERR_RFC4884:
return true;
}
/* IPV6_HOPOPTS, IPV6_RTHDRDSTOPTS, IPV6_RTHDR, IPV6_DSTOPTS are
* not supported
*/
/* IPV6_MULTICAST_HOPS, IPV6_MULTICAST_LOOP, IPV6_UNICAST_IF,
* IPV6_MULTICAST_IF, IPV6_ADDRFORM,
* IPV6_ADD_MEMBERSHIP, IPV6_DROP_MEMBERSHIP, IPV6_JOIN_ANYCAST,
* IPV6_LEAVE_ANYCAST, IPV6_MULTICAST_ALL, MCAST_JOIN_GROUP, MCAST_LEAVE_GROUP,
* MCAST_JOIN_SOURCE_GROUP, MCAST_LEAVE_SOURCE_GROUP,
* MCAST_BLOCK_SOURCE, MCAST_UNBLOCK_SOURCE, MCAST_MSFILTER
* are not supported better not deal with mcast
*/
/* IPV6_ROUTER_ALERT, IPV6_ROUTER_ALERT_ISOLATE are not supported, since are evil */
/* IPV6_IPSEC_POLICY, IPV6_XFRM_POLICY are not supported */
/* IPV6_ADDR_PREFERENCES is not supported, we must be careful with subflows */
return false;
}
if (level == SOL_TCP) {
switch (optname) {
/* the following are no-op or should work just fine */
case TCP_THIN_DUPACK:
case TCP_DEFER_ACCEPT:
/* the following need some love */
case TCP_MAXSEG:
case TCP_NODELAY:
case TCP_THIN_LINEAR_TIMEOUTS:
case TCP_CONGESTION:
case TCP_CORK:
case TCP_KEEPIDLE:
case TCP_KEEPINTVL:
case TCP_KEEPCNT:
case TCP_SYNCNT:
case TCP_SAVE_SYN:
case TCP_LINGER2:
case TCP_WINDOW_CLAMP:
case TCP_QUICKACK:
case TCP_USER_TIMEOUT:
case TCP_TIMESTAMP:
case TCP_NOTSENT_LOWAT:
case TCP_TX_DELAY:
case TCP_INQ:
case TCP_FASTOPEN:
case TCP_FASTOPEN_CONNECT:
case TCP_FASTOPEN_KEY:
case TCP_FASTOPEN_NO_COOKIE:
return true;
}
/* TCP_MD5SIG, TCP_MD5SIG_EXT are not supported, MD5 is not compatible with MPTCP */
/* TCP_REPAIR, TCP_REPAIR_QUEUE, TCP_QUEUE_SEQ, TCP_REPAIR_OPTIONS,
* TCP_REPAIR_WINDOW are not supported, better avoid this mess
*/
}
return false;
}
static int mptcp_setsockopt_sol_tcp_congestion(struct mptcp_sock *msk, sockptr_t optval,
unsigned int optlen)
{
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
char name[TCP_CA_NAME_MAX];
bool cap_net_admin;
int ret;
if (optlen < 1)
return -EINVAL;
ret = strncpy_from_sockptr(name, optval,
min_t(long, TCP_CA_NAME_MAX - 1, optlen));
if (ret < 0)
return -EFAULT;
name[ret] = 0;
cap_net_admin = ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN);
ret = 0;
lock_sock(sk);
sockopt_seq_inc(msk);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
int err;
lock_sock(ssk);
err = tcp_set_congestion_control(ssk, name, true, cap_net_admin);
if (err < 0 && ret == 0)
ret = err;
subflow->setsockopt_seq = msk->setsockopt_seq;
release_sock(ssk);
}
if (ret == 0)
strcpy(msk->ca_name, name);
release_sock(sk);
return ret;
}
static int mptcp_setsockopt_sol_tcp_cork(struct mptcp_sock *msk, sockptr_t optval,
unsigned int optlen)
{
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
int val;
if (optlen < sizeof(int))
return -EINVAL;
if (copy_from_sockptr(&val, optval, sizeof(val)))
return -EFAULT;
lock_sock(sk);
sockopt_seq_inc(msk);
msk->cork = !!val;
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
lock_sock(ssk);
__tcp_sock_set_cork(ssk, !!val);
release_sock(ssk);
}
if (!val)
mptcp_check_and_set_pending(sk);
release_sock(sk);
return 0;
}
static int mptcp_setsockopt_sol_tcp_nodelay(struct mptcp_sock *msk, sockptr_t optval,
unsigned int optlen)
{
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
int val;
if (optlen < sizeof(int))
return -EINVAL;
if (copy_from_sockptr(&val, optval, sizeof(val)))
return -EFAULT;
lock_sock(sk);
sockopt_seq_inc(msk);
msk->nodelay = !!val;
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
lock_sock(ssk);
__tcp_sock_set_nodelay(ssk, !!val);
release_sock(ssk);
}
if (val)
mptcp_check_and_set_pending(sk);
release_sock(sk);
return 0;
}
static int mptcp_setsockopt_sol_ip_set(struct mptcp_sock *msk, int optname,
sockptr_t optval, unsigned int optlen)
{
struct sock *sk = (struct sock *)msk;
struct sock *ssk;
int err;
err = ip_setsockopt(sk, SOL_IP, optname, optval, optlen);
if (err != 0)
return err;
lock_sock(sk);
ssk = __mptcp_nmpc_sk(msk);
if (IS_ERR(ssk)) {
release_sock(sk);
return PTR_ERR(ssk);
}
switch (optname) {
case IP_FREEBIND:
inet_assign_bit(FREEBIND, ssk, inet_test_bit(FREEBIND, sk));
break;
case IP_TRANSPARENT:
inet_assign_bit(TRANSPARENT, ssk,
inet_test_bit(TRANSPARENT, sk));
break;
case IP_BIND_ADDRESS_NO_PORT:
inet_assign_bit(BIND_ADDRESS_NO_PORT, ssk,
inet_test_bit(BIND_ADDRESS_NO_PORT, sk));
break;
case IP_LOCAL_PORT_RANGE:
WRITE_ONCE(inet_sk(ssk)->local_port_range,
READ_ONCE(inet_sk(sk)->local_port_range));
break;
default:
release_sock(sk);
WARN_ON_ONCE(1);
return -EOPNOTSUPP;
}
sockopt_seq_inc(msk);
release_sock(sk);
return 0;
}
static int mptcp_setsockopt_v4_set_tos(struct mptcp_sock *msk, int optname,
sockptr_t optval, unsigned int optlen)
{
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
int err, val;
err = ip_setsockopt(sk, SOL_IP, optname, optval, optlen);
if (err != 0)
return err;
lock_sock(sk);
sockopt_seq_inc(msk);
val = READ_ONCE(inet_sk(sk)->tos);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
bool slow;
slow = lock_sock_fast(ssk);
__ip_sock_set_tos(ssk, val);
unlock_sock_fast(ssk, slow);
}
release_sock(sk);
return 0;
}
static int mptcp_setsockopt_v4(struct mptcp_sock *msk, int optname,
sockptr_t optval, unsigned int optlen)
{
switch (optname) {
case IP_FREEBIND:
case IP_TRANSPARENT:
case IP_BIND_ADDRESS_NO_PORT:
case IP_LOCAL_PORT_RANGE:
return mptcp_setsockopt_sol_ip_set(msk, optname, optval, optlen);
case IP_TOS:
return mptcp_setsockopt_v4_set_tos(msk, optname, optval, optlen);
}
return -EOPNOTSUPP;
}
static int mptcp_setsockopt_first_sf_only(struct mptcp_sock *msk, int level, int optname,
sockptr_t optval, unsigned int optlen)
{
struct sock *sk = (struct sock *)msk;
struct sock *ssk;
int ret;
/* Limit to first subflow, before the connection establishment */
lock_sock(sk);
ssk = __mptcp_nmpc_sk(msk);
if (IS_ERR(ssk)) {
ret = PTR_ERR(ssk);
goto unlock;
}
ret = tcp_setsockopt(ssk, level, optname, optval, optlen);
unlock:
release_sock(sk);
return ret;
}
static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
sockptr_t optval, unsigned int optlen)
{
struct sock *sk = (void *)msk;
int ret, val;
switch (optname) {
case TCP_INQ:
ret = mptcp_get_int_option(msk, optval, optlen, &val);
if (ret)
return ret;
if (val < 0 || val > 1)
return -EINVAL;
lock_sock(sk);
msk->recvmsg_inq = !!val;
release_sock(sk);
return 0;
case TCP_ULP:
return -EOPNOTSUPP;
case TCP_CONGESTION:
return mptcp_setsockopt_sol_tcp_congestion(msk, optval, optlen);
case TCP_CORK:
return mptcp_setsockopt_sol_tcp_cork(msk, optval, optlen);
case TCP_NODELAY:
return mptcp_setsockopt_sol_tcp_nodelay(msk, optval, optlen);
case TCP_DEFER_ACCEPT:
/* See tcp.c: TCP_DEFER_ACCEPT does not fail */
mptcp_setsockopt_first_sf_only(msk, SOL_TCP, optname, optval, optlen);
return 0;
case TCP_FASTOPEN:
case TCP_FASTOPEN_CONNECT:
case TCP_FASTOPEN_KEY:
case TCP_FASTOPEN_NO_COOKIE:
return mptcp_setsockopt_first_sf_only(msk, SOL_TCP, optname,
optval, optlen);
}
return -EOPNOTSUPP;
}
int mptcp_setsockopt(struct sock *sk, int level, int optname,
sockptr_t optval, unsigned int optlen)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct sock *ssk;
pr_debug("msk=%p", msk);
if (level == SOL_SOCKET)
return mptcp_setsockopt_sol_socket(msk, optname, optval, optlen);
if (!mptcp_supported_sockopt(level, optname))
return -ENOPROTOOPT;
/* @@ the meaning of setsockopt() when the socket is connected and
* there are multiple subflows is not yet defined. It is up to the
* MPTCP-level socket to configure the subflows until the subflow
* is in TCP fallback, when TCP socket options are passed through
* to the one remaining subflow.
*/
lock_sock(sk);
ssk = __mptcp_tcp_fallback(msk);
release_sock(sk);
if (ssk)
return tcp_setsockopt(ssk, level, optname, optval, optlen);
if (level == SOL_IP)
return mptcp_setsockopt_v4(msk, optname, optval, optlen);
if (level == SOL_IPV6)
return mptcp_setsockopt_v6(msk, optname, optval, optlen);
if (level == SOL_TCP)
return mptcp_setsockopt_sol_tcp(msk, optname, optval, optlen);
return -EOPNOTSUPP;
}
static int mptcp_getsockopt_first_sf_only(struct mptcp_sock *msk, int level, int optname,
char __user *optval, int __user *optlen)
{
struct sock *sk = (struct sock *)msk;
struct sock *ssk;
int ret;
lock_sock(sk);
ssk = msk->first;
if (ssk) {
ret = tcp_getsockopt(ssk, level, optname, optval, optlen);
goto out;
}
ssk = __mptcp_nmpc_sk(msk);
if (IS_ERR(ssk)) {
ret = PTR_ERR(ssk);
goto out;
}
ret = tcp_getsockopt(ssk, level, optname, optval, optlen);
out:
release_sock(sk);
return ret;
}
void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
{
struct sock *sk = (struct sock *)msk;
u32 flags = 0;
bool slow;
memset(info, 0, sizeof(*info));
info->mptcpi_subflows = READ_ONCE(msk->pm.subflows);
info->mptcpi_add_addr_signal = READ_ONCE(msk->pm.add_addr_signaled);
info->mptcpi_add_addr_accepted = READ_ONCE(msk->pm.add_addr_accepted);
info->mptcpi_local_addr_used = READ_ONCE(msk->pm.local_addr_used);
if (inet_sk_state_load(sk) == TCP_LISTEN)
return;
/* The following limits only make sense for the in-kernel PM */
if (mptcp_pm_is_kernel(msk)) {
info->mptcpi_subflows_max =
mptcp_pm_get_subflows_max(msk);
info->mptcpi_add_addr_signal_max =
mptcp_pm_get_add_addr_signal_max(msk);
info->mptcpi_add_addr_accepted_max =
mptcp_pm_get_add_addr_accept_max(msk);
info->mptcpi_local_addr_max =
mptcp_pm_get_local_addr_max(msk);
}
if (__mptcp_check_fallback(msk))
flags |= MPTCP_INFO_FLAG_FALLBACK;
if (READ_ONCE(msk->can_ack))
flags |= MPTCP_INFO_FLAG_REMOTE_KEY_RECEIVED;
info->mptcpi_flags = flags;
mptcp_data_lock(sk);
info->mptcpi_snd_una = msk->snd_una;
info->mptcpi_rcv_nxt = msk->ack_seq;
info->mptcpi_bytes_acked = msk->bytes_acked;
mptcp_data_unlock(sk);
slow = lock_sock_fast(sk);
info->mptcpi_csum_enabled = msk->csum_enabled;
info->mptcpi_token = msk->token;
info->mptcpi_write_seq = msk->write_seq;
info->mptcpi_retransmits = inet_csk(sk)->icsk_retransmits;
info->mptcpi_bytes_sent = msk->bytes_sent;
info->mptcpi_bytes_received = msk->bytes_received;
info->mptcpi_bytes_retrans = msk->bytes_retrans;
info->mptcpi_subflows_total = info->mptcpi_subflows +
__mptcp_has_initial_subflow(msk);
unlock_sock_fast(sk, slow);
}
EXPORT_SYMBOL_GPL(mptcp_diag_fill_info);
static int mptcp_getsockopt_info(struct mptcp_sock *msk, char __user *optval, int __user *optlen)
{
struct mptcp_info m_info;
int len;
if (get_user(len, optlen))
return -EFAULT;
len = min_t(unsigned int, len, sizeof(struct mptcp_info));
mptcp_diag_fill_info(msk, &m_info);
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, &m_info, len))
return -EFAULT;
return 0;
}
static int mptcp_put_subflow_data(struct mptcp_subflow_data *sfd,
char __user *optval,
u32 copied,
int __user *optlen)
{
u32 copylen = min_t(u32, sfd->size_subflow_data, sizeof(*sfd));
if (copied)
copied += sfd->size_subflow_data;
else
copied = copylen;
if (put_user(copied, optlen))
return -EFAULT;
if (copy_to_user(optval, sfd, copylen))
return -EFAULT;
return 0;
}
static int mptcp_get_subflow_data(struct mptcp_subflow_data *sfd,
char __user *optval,
int __user *optlen)
{
int len, copylen;
if (get_user(len, optlen))
return -EFAULT;
/* if mptcp_subflow_data size is changed, need to adjust
* this function to deal with programs using old version.
*/
BUILD_BUG_ON(sizeof(*sfd) != MIN_INFO_OPTLEN_SIZE);
if (len < MIN_INFO_OPTLEN_SIZE)
return -EINVAL;
memset(sfd, 0, sizeof(*sfd));
copylen = min_t(unsigned int, len, sizeof(*sfd));
if (copy_from_user(sfd, optval, copylen))
return -EFAULT;
/* size_subflow_data is u32, but len is signed */
if (sfd->size_subflow_data > INT_MAX ||
sfd->size_user > INT_MAX)
return -EINVAL;
if (sfd->size_subflow_data < MIN_INFO_OPTLEN_SIZE ||
sfd->size_subflow_data > len)
return -EINVAL;
if (sfd->num_subflows || sfd->size_kernel)
return -EINVAL;
return len - sfd->size_subflow_data;
}
static int mptcp_getsockopt_tcpinfo(struct mptcp_sock *msk, char __user *optval,
int __user *optlen)
{
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
unsigned int sfcount = 0, copied = 0;
struct mptcp_subflow_data sfd;
char __user *infoptr;
int len;
len = mptcp_get_subflow_data(&sfd, optval, optlen);
if (len < 0)
return len;
sfd.size_kernel = sizeof(struct tcp_info);
sfd.size_user = min_t(unsigned int, sfd.size_user,
sizeof(struct tcp_info));
infoptr = optval + sfd.size_subflow_data;
lock_sock(sk);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
++sfcount;
if (len && len >= sfd.size_user) {
struct tcp_info info;
tcp_get_info(ssk, &info);
if (copy_to_user(infoptr, &info, sfd.size_user)) {
release_sock(sk);
return -EFAULT;
}
infoptr += sfd.size_user;
copied += sfd.size_user;
len -= sfd.size_user;
}
}
release_sock(sk);
sfd.num_subflows = sfcount;
if (mptcp_put_subflow_data(&sfd, optval, copied, optlen))
return -EFAULT;
return 0;
}
static void mptcp_get_sub_addrs(const struct sock *sk, struct mptcp_subflow_addrs *a)
{
const struct inet_sock *inet = inet_sk(sk);
memset(a, 0, sizeof(*a));
if (sk->sk_family == AF_INET) {
a->sin_local.sin_family = AF_INET;
a->sin_local.sin_port = inet->inet_sport;
a->sin_local.sin_addr.s_addr = inet->inet_rcv_saddr;
if (!a->sin_local.sin_addr.s_addr)
a->sin_local.sin_addr.s_addr = inet->inet_saddr;
a->sin_remote.sin_family = AF_INET;
a->sin_remote.sin_port = inet->inet_dport;
a->sin_remote.sin_addr.s_addr = inet->inet_daddr;
#if IS_ENABLED(CONFIG_IPV6)
} else if (sk->sk_family == AF_INET6) {
const struct ipv6_pinfo *np = inet6_sk(sk);
if (WARN_ON_ONCE(!np))
return;
a->sin6_local.sin6_family = AF_INET6;
a->sin6_local.sin6_port = inet->inet_sport;
if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
a->sin6_local.sin6_addr = np->saddr;
else
a->sin6_local.sin6_addr = sk->sk_v6_rcv_saddr;
a->sin6_remote.sin6_family = AF_INET6;
a->sin6_remote.sin6_port = inet->inet_dport;
a->sin6_remote.sin6_addr = sk->sk_v6_daddr;
#endif
}
}
static int mptcp_getsockopt_subflow_addrs(struct mptcp_sock *msk, char __user *optval,
int __user *optlen)
{
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
unsigned int sfcount = 0, copied = 0;
struct mptcp_subflow_data sfd;
char __user *addrptr;
int len;
len = mptcp_get_subflow_data(&sfd, optval, optlen);
if (len < 0)
return len;
sfd.size_kernel = sizeof(struct mptcp_subflow_addrs);
sfd.size_user = min_t(unsigned int, sfd.size_user,
sizeof(struct mptcp_subflow_addrs));
addrptr = optval + sfd.size_subflow_data;
lock_sock(sk);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
++sfcount;
if (len && len >= sfd.size_user) {
struct mptcp_subflow_addrs a;
mptcp_get_sub_addrs(ssk, &a);
if (copy_to_user(addrptr, &a, sfd.size_user)) {
release_sock(sk);
return -EFAULT;
}
addrptr += sfd.size_user;
copied += sfd.size_user;
len -= sfd.size_user;
}
}
release_sock(sk);
sfd.num_subflows = sfcount;
if (mptcp_put_subflow_data(&sfd, optval, copied, optlen))
return -EFAULT;
return 0;
}
static int mptcp_get_full_info(struct mptcp_full_info *mfi,
char __user *optval,
int __user *optlen)
{
int len;
BUILD_BUG_ON(offsetof(struct mptcp_full_info, mptcp_info) !=
MIN_FULL_INFO_OPTLEN_SIZE);
if (get_user(len, optlen))
return -EFAULT;
if (len < MIN_FULL_INFO_OPTLEN_SIZE)
return -EINVAL;
memset(mfi, 0, sizeof(*mfi));
if (copy_from_user(mfi, optval, MIN_FULL_INFO_OPTLEN_SIZE))
return -EFAULT;
if (mfi->size_tcpinfo_kernel ||
mfi->size_sfinfo_kernel ||
mfi->num_subflows)
return -EINVAL;
if (mfi->size_sfinfo_user > INT_MAX ||
mfi->size_tcpinfo_user > INT_MAX)
return -EINVAL;
return len - MIN_FULL_INFO_OPTLEN_SIZE;
}
static int mptcp_put_full_info(struct mptcp_full_info *mfi,
char __user *optval,
u32 copylen,
int __user *optlen)
{
copylen += MIN_FULL_INFO_OPTLEN_SIZE;
if (put_user(copylen, optlen))
return -EFAULT;
if (copy_to_user(optval, mfi, copylen))
return -EFAULT;
return 0;
}
static int mptcp_getsockopt_full_info(struct mptcp_sock *msk, char __user *optval,
int __user *optlen)
{
unsigned int sfcount = 0, copylen = 0;
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
void __user *tcpinfoptr, *sfinfoptr;
struct mptcp_full_info mfi;
int len;
len = mptcp_get_full_info(&mfi, optval, optlen);
if (len < 0)
return len;
/* don't bother filling the mptcp info if there is not enough
* user-space-provided storage
*/
if (len > 0) {
mptcp_diag_fill_info(msk, &mfi.mptcp_info);
copylen += min_t(unsigned int, len, sizeof(struct mptcp_info));
}
mfi.size_tcpinfo_kernel = sizeof(struct tcp_info);
mfi.size_tcpinfo_user = min_t(unsigned int, mfi.size_tcpinfo_user,
sizeof(struct tcp_info));
sfinfoptr = u64_to_user_ptr(mfi.subflow_info);
mfi.size_sfinfo_kernel = sizeof(struct mptcp_subflow_info);
mfi.size_sfinfo_user = min_t(unsigned int, mfi.size_sfinfo_user,
sizeof(struct mptcp_subflow_info));
tcpinfoptr = u64_to_user_ptr(mfi.tcp_info);
lock_sock(sk);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
struct mptcp_subflow_info sfinfo;
struct tcp_info tcp_info;
if (sfcount++ >= mfi.size_arrays_user)
continue;
/* fetch addr/tcp_info only if the user space buffers
* are wide enough
*/
memset(&sfinfo, 0, sizeof(sfinfo));
sfinfo.id = subflow->subflow_id;
if (mfi.size_sfinfo_user >
offsetof(struct mptcp_subflow_info, addrs))
mptcp_get_sub_addrs(ssk, &sfinfo.addrs);
if (copy_to_user(sfinfoptr, &sfinfo, mfi.size_sfinfo_user))
goto fail_release;
if (mfi.size_tcpinfo_user) {
tcp_get_info(ssk, &tcp_info);
if (copy_to_user(tcpinfoptr, &tcp_info,
mfi.size_tcpinfo_user))
goto fail_release;
}
tcpinfoptr += mfi.size_tcpinfo_user;
sfinfoptr += mfi.size_sfinfo_user;
}
release_sock(sk);
mfi.num_subflows = sfcount;
if (mptcp_put_full_info(&mfi, optval, copylen, optlen))
return -EFAULT;
return 0;
fail_release:
release_sock(sk);
return -EFAULT;
}
static int mptcp_put_int_option(struct mptcp_sock *msk, char __user *optval,
int __user *optlen, int val)
{
int len;
if (get_user(len, optlen))
return -EFAULT;
if (len < 0)
return -EINVAL;
if (len < sizeof(int) && len > 0 && val >= 0 && val <= 255) {
unsigned char ucval = (unsigned char)val;
len = 1;
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, &ucval, 1))
return -EFAULT;
} else {
len = min_t(unsigned int, len, sizeof(int));
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, &val, len))
return -EFAULT;
}
return 0;
}
static int mptcp_getsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
char __user *optval, int __user *optlen)
{
switch (optname) {
case TCP_ULP:
case TCP_CONGESTION:
case TCP_INFO:
case TCP_CC_INFO:
case TCP_DEFER_ACCEPT:
case TCP_FASTOPEN:
case TCP_FASTOPEN_CONNECT:
case TCP_FASTOPEN_KEY:
case TCP_FASTOPEN_NO_COOKIE:
return mptcp_getsockopt_first_sf_only(msk, SOL_TCP, optname,
optval, optlen);
case TCP_INQ:
return mptcp_put_int_option(msk, optval, optlen, msk->recvmsg_inq);
case TCP_CORK:
return mptcp_put_int_option(msk, optval, optlen, msk->cork);
case TCP_NODELAY:
return mptcp_put_int_option(msk, optval, optlen, msk->nodelay);
}
return -EOPNOTSUPP;
}
static int mptcp_getsockopt_v4(struct mptcp_sock *msk, int optname,
char __user *optval, int __user *optlen)
{
struct sock *sk = (void *)msk;
switch (optname) {
case IP_TOS:
return mptcp_put_int_option(msk, optval, optlen, READ_ONCE(inet_sk(sk)->tos));
case IP_BIND_ADDRESS_NO_PORT:
return mptcp_put_int_option(msk, optval, optlen,
inet_test_bit(BIND_ADDRESS_NO_PORT, sk));
case IP_LOCAL_PORT_RANGE:
return mptcp_put_int_option(msk, optval, optlen,
READ_ONCE(inet_sk(sk)->local_port_range));
}
return -EOPNOTSUPP;
}
static int mptcp_getsockopt_sol_mptcp(struct mptcp_sock *msk, int optname,
char __user *optval, int __user *optlen)
{
switch (optname) {
case MPTCP_INFO:
return mptcp_getsockopt_info(msk, optval, optlen);
case MPTCP_FULL_INFO:
return mptcp_getsockopt_full_info(msk, optval, optlen);
case MPTCP_TCPINFO:
return mptcp_getsockopt_tcpinfo(msk, optval, optlen);
case MPTCP_SUBFLOW_ADDRS:
return mptcp_getsockopt_subflow_addrs(msk, optval, optlen);
}
return -EOPNOTSUPP;
}
int mptcp_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *option)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct sock *ssk;
pr_debug("msk=%p", msk);
/* @@ the meaning of setsockopt() when the socket is connected and
* there are multiple subflows is not yet defined. It is up to the
* MPTCP-level socket to configure the subflows until the subflow
* is in TCP fallback, when socket options are passed through
* to the one remaining subflow.
*/
lock_sock(sk);
ssk = __mptcp_tcp_fallback(msk);
release_sock(sk);
if (ssk)
return tcp_getsockopt(ssk, level, optname, optval, option);
if (level == SOL_IP)
return mptcp_getsockopt_v4(msk, optname, optval, option);
if (level == SOL_TCP)
return mptcp_getsockopt_sol_tcp(msk, optname, optval, option);
if (level == SOL_MPTCP)
return mptcp_getsockopt_sol_mptcp(msk, optname, optval, option);
return -EOPNOTSUPP;
}
static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
{
static const unsigned int tx_rx_locks = SOCK_RCVBUF_LOCK | SOCK_SNDBUF_LOCK;
struct sock *sk = (struct sock *)msk;
if (ssk->sk_prot->keepalive) {
if (sock_flag(sk, SOCK_KEEPOPEN))
ssk->sk_prot->keepalive(ssk, 1);
else
ssk->sk_prot->keepalive(ssk, 0);
}
ssk->sk_priority = sk->sk_priority;
ssk->sk_bound_dev_if = sk->sk_bound_dev_if;
ssk->sk_incoming_cpu = sk->sk_incoming_cpu;
ssk->sk_ipv6only = sk->sk_ipv6only;
__ip_sock_set_tos(ssk, inet_sk(sk)->tos);
if (sk->sk_userlocks & tx_rx_locks) {
ssk->sk_userlocks |= sk->sk_userlocks & tx_rx_locks;
if (sk->sk_userlocks & SOCK_SNDBUF_LOCK) {
WRITE_ONCE(ssk->sk_sndbuf, sk->sk_sndbuf);
mptcp_subflow_ctx(ssk)->cached_sndbuf = sk->sk_sndbuf;
}
if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
WRITE_ONCE(ssk->sk_rcvbuf, sk->sk_rcvbuf);
}
if (sock_flag(sk, SOCK_LINGER)) {
ssk->sk_lingertime = sk->sk_lingertime;
sock_set_flag(ssk, SOCK_LINGER);
} else {
sock_reset_flag(ssk, SOCK_LINGER);
}
if (sk->sk_mark != ssk->sk_mark) {
ssk->sk_mark = sk->sk_mark;
sk_dst_reset(ssk);
}
sock_valbool_flag(ssk, SOCK_DBG, sock_flag(sk, SOCK_DBG));
if (inet_csk(sk)->icsk_ca_ops != inet_csk(ssk)->icsk_ca_ops)
tcp_set_congestion_control(ssk, msk->ca_name, false, true);
__tcp_sock_set_cork(ssk, !!msk->cork);
__tcp_sock_set_nodelay(ssk, !!msk->nodelay);
inet_assign_bit(TRANSPARENT, ssk, inet_test_bit(TRANSPARENT, sk));
inet_assign_bit(FREEBIND, ssk, inet_test_bit(FREEBIND, sk));
inet_assign_bit(BIND_ADDRESS_NO_PORT, ssk, inet_test_bit(BIND_ADDRESS_NO_PORT, sk));
WRITE_ONCE(inet_sk(ssk)->local_port_range, READ_ONCE(inet_sk(sk)->local_port_range));
}
void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
msk_owned_by_me(msk);
ssk->sk_rcvlowat = 0;
/* subflows must ignore any latency-related settings: will not affect
* the user-space - only the msk is relevant - but will foul the
* mptcp scheduler
*/
tcp_sk(ssk)->notsent_lowat = UINT_MAX;
if (READ_ONCE(subflow->setsockopt_seq) != msk->setsockopt_seq) {
sync_socket_options(msk, ssk);
subflow->setsockopt_seq = msk->setsockopt_seq;
}
}
/* unfortunately this is different enough from the tcp version so
* that we can't factor it out
*/
int mptcp_set_rcvlowat(struct sock *sk, int val)
{
struct mptcp_subflow_context *subflow;
int space, cap;
if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
cap = sk->sk_rcvbuf >> 1;
else
cap = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2]) >> 1;
val = min(val, cap);
WRITE_ONCE(sk->sk_rcvlowat, val ? : 1);
/* Check if we need to signal EPOLLIN right now */
if (mptcp_epollin_ready(sk))
sk->sk_data_ready(sk);
if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
return 0;
space = __tcp_space_from_win(mptcp_sk(sk)->scaling_ratio, val);
if (space <= sk->sk_rcvbuf)
return 0;
/* propagate the rcvbuf changes to all the subflows */
WRITE_ONCE(sk->sk_rcvbuf, space);
mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
bool slow;
slow = lock_sock_fast(ssk);
WRITE_ONCE(ssk->sk_rcvbuf, space);
tcp_sk(ssk)->window_clamp = val;
unlock_sock_fast(ssk, slow);
}
return 0;
}