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-rw-r--r--net/mptcp/sockopt.c756
1 files changed, 756 insertions, 0 deletions
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
new file mode 100644
index 000000000000..00d941b66c1e
--- /dev/null
+++ b/net/mptcp/sockopt.c
@@ -0,0 +1,756 @@
+// 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"
+
+static struct sock *__mptcp_tcp_fallback(struct mptcp_sock *msk)
+{
+ sock_owned_by_me((const struct sock *)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:
+ 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);
+ 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) {
+ 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_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;
+ }
+
+ return -ENOPROTOOPT;
+}
+
+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 socket *ssock;
+ int ret;
+
+ switch (optname) {
+ case SO_REUSEPORT:
+ case SO_REUSEADDR:
+ case SO_BINDTODEVICE:
+ case SO_BINDTOIFINDEX:
+ lock_sock(sk);
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock) {
+ release_sock(sk);
+ return -EINVAL;
+ }
+
+ ret = sock_setsockopt(ssock, SOL_SOCKET, optname, optval, optlen);
+ if (ret == 0) {
+ if (optname == SO_REUSEPORT)
+ sk->sk_reuseport = ssock->sk->sk_reuseport;
+ else if (optname == SO_REUSEADDR)
+ sk->sk_reuse = ssock->sk->sk_reuse;
+ else if (optname == SO_BINDTODEVICE)
+ sk->sk_bound_dev_if = ssock->sk->sk_bound_dev_if;
+ else if (optname == SO_BINDTOIFINDEX)
+ sk->sk_bound_dev_if = ssock->sk->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:
+ return mptcp_setsockopt_sol_socket_int(msk, optname, optval, optlen);
+ case SO_LINGER:
+ return mptcp_setsockopt_sol_socket_linger(msk, optval, optlen);
+ case SO_NO_CHECK:
+ case SO_DONTROUTE:
+ case SO_BROADCAST:
+ case SO_BSDCOMPAT:
+ case SO_PASSCRED:
+ case SO_PASSSEC:
+ case SO_RXQ_OVFL:
+ case SO_WIFI_STATUS:
+ case SO_NOFCS:
+ case SO_SELECT_ERR_QUEUE:
+ return 0;
+ }
+
+ return sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname, optval, optlen);
+}
+
+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 socket *ssock;
+
+ switch (optname) {
+ case IPV6_V6ONLY:
+ lock_sock(sk);
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock) {
+ release_sock(sk);
+ return -EINVAL;
+ }
+
+ ret = tcp_setsockopt(ssock->sk, SOL_IPV6, optname, optval, optlen);
+ if (ret == 0)
+ sk->sk_ipv6only = ssock->sk->sk_ipv6only;
+
+ release_sock(sk);
+ break;
+ }
+
+ return ret;
+}
+
+static bool mptcp_supported_sockopt(int level, int optname)
+{
+ if (level == SOL_SOCKET) {
+ switch (optname) {
+ case SO_DEBUG:
+ case SO_REUSEPORT:
+ case SO_REUSEADDR:
+
+ /* the following ones need a better implementation,
+ * but are quite common we want to preserve them
+ */
+ case SO_BINDTODEVICE:
+ case SO_SNDBUF:
+ case SO_SNDBUFFORCE:
+ case SO_RCVBUF:
+ case SO_RCVBUFFORCE:
+ case SO_KEEPALIVE:
+ case SO_PRIORITY:
+ case SO_LINGER:
+ case SO_TIMESTAMP_OLD:
+ case SO_TIMESTAMP_NEW:
+ case SO_TIMESTAMPNS_OLD:
+ case SO_TIMESTAMPNS_NEW:
+ case SO_TIMESTAMPING_OLD:
+ case SO_TIMESTAMPING_NEW:
+ case SO_RCVLOWAT:
+ case SO_RCVTIMEO_OLD:
+ case SO_RCVTIMEO_NEW:
+ case SO_SNDTIMEO_OLD:
+ case SO_SNDTIMEO_NEW:
+ case SO_MARK:
+ case SO_INCOMING_CPU:
+ case SO_BINDTOIFINDEX:
+ case SO_BUSY_POLL:
+ case SO_PREFER_BUSY_POLL:
+ case SO_BUSY_POLL_BUDGET:
+
+ /* next ones are no-op for plain TCP */
+ case SO_NO_CHECK:
+ case SO_DONTROUTE:
+ case SO_BROADCAST:
+ case SO_BSDCOMPAT:
+ case SO_PASSCRED:
+ case SO_PASSSEC:
+ case SO_RXQ_OVFL:
+ case SO_WIFI_STATUS:
+ case SO_NOFCS:
+ case SO_SELECT_ERR_QUEUE:
+ return true;
+ }
+
+ /* 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 false;
+ }
+ if (level == SOL_IP) {
+ switch (optname) {
+ /* should work fine */
+ case IP_FREEBIND:
+ case IP_TRANSPARENT:
+
+ /* 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_BIND_ADDRESS_NO_PORT:
+ 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_ULP:
+ 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:
+ 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
+ */
+ /* TCP_FASTOPEN_KEY, TCP_FASTOPEN TCP_FASTOPEN_CONNECT, TCP_FASTOPEN_NO_COOKIE,
+ * are not supported fastopen is currently unsupported
+ */
+ /* TCP_INQ is currently unsupported, needs some recvmsg work */
+ }
+ 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)
+ tcp_set_congestion_control(sk, name, false, cap_net_admin);
+
+ release_sock(sk);
+ return ret;
+}
+
+static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
+ sockptr_t optval, unsigned int optlen)
+{
+ switch (optname) {
+ case TCP_ULP:
+ return -EOPNOTSUPP;
+ case TCP_CONGESTION:
+ return mptcp_setsockopt_sol_tcp_congestion(msk, 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 (!mptcp_supported_sockopt(level, optname))
+ return -ENOPROTOOPT;
+
+ if (level == SOL_SOCKET)
+ return mptcp_setsockopt_sol_socket(msk, optname, optval, optlen);
+
+ /* @@ 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_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 socket *ssock;
+ int ret = -EINVAL;
+ struct sock *ssk;
+
+ lock_sock(sk);
+ ssk = msk->first;
+ if (ssk) {
+ ret = tcp_getsockopt(ssk, level, optname, optval, optlen);
+ goto out;
+ }
+
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock)
+ goto out;
+
+ ret = tcp_getsockopt(ssock->sk, level, optname, optval, optlen);
+
+out:
+ release_sock(sk);
+ return ret;
+}
+
+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:
+ return mptcp_getsockopt_first_sf_only(msk, SOL_TCP, optname,
+ 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_TCP)
+ return mptcp_getsockopt_sol_tcp(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;
+
+ 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);
+ 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, inet_csk(sk)->icsk_ca_ops->name, false, true);
+}
+
+static void __mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk)
+{
+ bool slow = lock_sock_fast(ssk);
+
+ sync_socket_options(msk, ssk);
+
+ unlock_sock_fast(ssk, slow);
+}
+
+void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+
+ msk_owned_by_me(msk);
+
+ if (READ_ONCE(subflow->setsockopt_seq) != msk->setsockopt_seq) {
+ __mptcp_sockopt_sync(msk, ssk);
+
+ subflow->setsockopt_seq = msk->setsockopt_seq;
+ }
+}
+
+void mptcp_sockopt_sync_all(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct sock *sk = (struct sock *)msk;
+ u32 seq;
+
+ seq = sockopt_seq_reset(sk);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+ u32 sseq = READ_ONCE(subflow->setsockopt_seq);
+
+ if (sseq != msk->setsockopt_seq) {
+ __mptcp_sockopt_sync(msk, ssk);
+ WRITE_ONCE(subflow->setsockopt_seq, seq);
+ } else if (sseq != seq) {
+ WRITE_ONCE(subflow->setsockopt_seq, seq);
+ }
+
+ cond_resched();
+ }
+
+ msk->setsockopt_seq = seq;
+}