// 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 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:
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;
}
release_sock(sk);
return ret;
}
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;
}
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);
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);
return -EOPNOTSUPP;
}
void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk)
{
msk_owned_by_me(msk);
}
void mptcp_sockopt_sync_all(struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow;
msk_owned_by_me(msk);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
mptcp_sockopt_sync(msk, ssk);
cond_resched();
}
}
