blob: 8959a74f707d4f10b87b5f30403121517750f307 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/* Multipath TCP
*
* Copyright (c) 2017 - 2019, Intel Corporation.
*/
#define pr_fmt(fmt) "MPTCP: " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/sched/signal.h>
#include <linux/atomic.h>
#include <net/sock.h>
#include <net/inet_common.h>
#include <net/inet_hashtables.h>
#include <net/protocol.h>
#include <net/tcp.h>
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
#include <net/transp_v6.h>
#endif
#include <net/mptcp.h>
#include "protocol.h"
#include "mib.h"
#define MPTCP_SAME_STATE TCP_MAX_STATES
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
struct mptcp6_sock {
struct mptcp_sock msk;
struct ipv6_pinfo np;
};
#endif
struct mptcp_skb_cb {
u32 offset;
};
#define MPTCP_SKB_CB(__skb) ((struct mptcp_skb_cb *)&((__skb)->cb[0]))
static struct percpu_counter mptcp_sockets_allocated;
/* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not
* completed yet or has failed, return the subflow socket.
* Otherwise return NULL.
*/
static struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
{
if (!msk->subflow || READ_ONCE(msk->can_ack))
return NULL;
return msk->subflow;
}
static bool __mptcp_needs_tcp_fallback(const struct mptcp_sock *msk)
{
return msk->first && !sk_is_mptcp(msk->first);
}
static struct socket *mptcp_is_tcpsk(struct sock *sk)
{
struct socket *sock = sk->sk_socket;
if (sock->sk != sk)
return NULL;
if (unlikely(sk->sk_prot == &tcp_prot)) {
/* we are being invoked after mptcp_accept() has
* accepted a non-mp-capable flow: sk is a tcp_sk,
* not an mptcp one.
*
* Hand the socket over to tcp so all further socket ops
* bypass mptcp.
*/
sock->ops = &inet_stream_ops;
return sock;
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
} else if (unlikely(sk->sk_prot == &tcpv6_prot)) {
sock->ops = &inet6_stream_ops;
return sock;
#endif
}
return NULL;
}
static struct socket *__mptcp_tcp_fallback(struct mptcp_sock *msk)
{
struct socket *sock;
sock_owned_by_me((const struct sock *)msk);
sock = mptcp_is_tcpsk((struct sock *)msk);
if (unlikely(sock))
return sock;
if (likely(!__mptcp_needs_tcp_fallback(msk)))
return NULL;
return msk->subflow;
}
static bool __mptcp_can_create_subflow(const struct mptcp_sock *msk)
{
return !msk->first;
}
static struct socket *__mptcp_socket_create(struct mptcp_sock *msk, int state)
{
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
struct socket *ssock;
int err;
ssock = __mptcp_tcp_fallback(msk);
if (unlikely(ssock))
return ssock;
ssock = __mptcp_nmpc_socket(msk);
if (ssock)
goto set_state;
if (!__mptcp_can_create_subflow(msk))
return ERR_PTR(-EINVAL);
err = mptcp_subflow_create_socket(sk, &ssock);
if (err)
return ERR_PTR(err);
msk->first = ssock->sk;
msk->subflow = ssock;
subflow = mptcp_subflow_ctx(ssock->sk);
list_add(&subflow->node, &msk->conn_list);
subflow->request_mptcp = 1;
set_state:
if (state != MPTCP_SAME_STATE)
inet_sk_state_store(sk, state);
return ssock;
}
static void __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
struct sk_buff *skb,
unsigned int offset, size_t copy_len)
{
struct sock *sk = (struct sock *)msk;
__skb_unlink(skb, &ssk->sk_receive_queue);
skb_set_owner_r(skb, sk);
__skb_queue_tail(&sk->sk_receive_queue, skb);
msk->ack_seq += copy_len;
MPTCP_SKB_CB(skb)->offset = offset;
}
/* both sockets must be locked */
static bool mptcp_subflow_dsn_valid(const struct mptcp_sock *msk,
struct sock *ssk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
u64 dsn = mptcp_subflow_get_mapped_dsn(subflow);
/* revalidate data sequence number.
*
* mptcp_subflow_data_available() is usually called
* without msk lock. Its unlikely (but possible)
* that msk->ack_seq has been advanced since the last
* call found in-sequence data.
*/
if (likely(dsn == msk->ack_seq))
return true;
subflow->data_avail = 0;
return mptcp_subflow_data_available(ssk);
}
static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
struct sock *ssk,
unsigned int *bytes)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
struct sock *sk = (struct sock *)msk;
unsigned int moved = 0;
bool more_data_avail;
struct tcp_sock *tp;
bool done = false;
if (!mptcp_subflow_dsn_valid(msk, ssk)) {
*bytes = 0;
return false;
}
if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
int rcvbuf = max(ssk->sk_rcvbuf, sk->sk_rcvbuf);
if (rcvbuf > sk->sk_rcvbuf)
sk->sk_rcvbuf = rcvbuf;
}
tp = tcp_sk(ssk);
do {
u32 map_remaining, offset;
u32 seq = tp->copied_seq;
struct sk_buff *skb;
bool fin;
/* try to move as much data as available */
map_remaining = subflow->map_data_len -
mptcp_subflow_get_map_offset(subflow);
skb = skb_peek(&ssk->sk_receive_queue);
if (!skb)
break;
offset = seq - TCP_SKB_CB(skb)->seq;
fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
if (fin) {
done = true;
seq++;
}
if (offset < skb->len) {
size_t len = skb->len - offset;
if (tp->urg_data)
done = true;
__mptcp_move_skb(msk, ssk, skb, offset, len);
seq += len;
moved += len;
if (WARN_ON_ONCE(map_remaining < len))
break;
} else {
WARN_ON_ONCE(!fin);
sk_eat_skb(ssk, skb);
done = true;
}
WRITE_ONCE(tp->copied_seq, seq);
more_data_avail = mptcp_subflow_data_available(ssk);
if (atomic_read(&sk->sk_rmem_alloc) > READ_ONCE(sk->sk_rcvbuf)) {
done = true;
break;
}
} while (more_data_avail);
*bytes = moved;
return done;
}
/* In most cases we will be able to lock the mptcp socket. If its already
* owned, we need to defer to the work queue to avoid ABBA deadlock.
*/
static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
{
struct sock *sk = (struct sock *)msk;
unsigned int moved = 0;
if (READ_ONCE(sk->sk_lock.owned))
return false;
if (unlikely(!spin_trylock_bh(&sk->sk_lock.slock)))
return false;
/* must re-check after taking the lock */
if (!READ_ONCE(sk->sk_lock.owned))
__mptcp_move_skbs_from_subflow(msk, ssk, &moved);
spin_unlock_bh(&sk->sk_lock.slock);
return moved > 0;
}
void mptcp_data_ready(struct sock *sk, struct sock *ssk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
set_bit(MPTCP_DATA_READY, &msk->flags);
if (atomic_read(&sk->sk_rmem_alloc) < READ_ONCE(sk->sk_rcvbuf) &&
move_skbs_to_msk(msk, ssk))
goto wake;
/* don't schedule if mptcp sk is (still) over limit */
if (atomic_read(&sk->sk_rmem_alloc) > READ_ONCE(sk->sk_rcvbuf))
goto wake;
/* mptcp socket is owned, release_cb should retry */
if (!test_and_set_bit(TCP_DELACK_TIMER_DEFERRED,
&sk->sk_tsq_flags)) {
sock_hold(sk);
/* need to try again, its possible release_cb() has already
* been called after the test_and_set_bit() above.
*/
move_skbs_to_msk(msk, ssk);
}
wake:
sk->sk_data_ready(sk);
}
static void __mptcp_flush_join_list(struct mptcp_sock *msk)
{
if (likely(list_empty(&msk->join_list)))
return;
spin_lock_bh(&msk->join_list_lock);
list_splice_tail_init(&msk->join_list, &msk->conn_list);
spin_unlock_bh(&msk->join_list_lock);
}
static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk)
{
long tout = ssk && inet_csk(ssk)->icsk_pending ?
inet_csk(ssk)->icsk_timeout - jiffies : 0;
if (tout <= 0)
tout = mptcp_sk(sk)->timer_ival;
mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
}
static bool mptcp_timer_pending(struct sock *sk)
{
return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
}
static void mptcp_reset_timer(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
unsigned long tout;
/* should never be called with mptcp level timer cleared */
tout = READ_ONCE(mptcp_sk(sk)->timer_ival);
if (WARN_ON_ONCE(!tout))
tout = TCP_RTO_MIN;
sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
}
void mptcp_data_acked(struct sock *sk)
{
mptcp_reset_timer(sk);
if (!sk_stream_is_writeable(sk) &&
schedule_work(&mptcp_sk(sk)->work))
sock_hold(sk);
}
void mptcp_subflow_eof(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
if (!test_and_set_bit(MPTCP_WORK_EOF, &msk->flags) &&
schedule_work(&msk->work))
sock_hold(sk);
}
static void mptcp_stop_timer(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
mptcp_sk(sk)->timer_ival = 0;
}
static bool mptcp_ext_cache_refill(struct mptcp_sock *msk)
{
if (!msk->cached_ext)
msk->cached_ext = __skb_ext_alloc();
return !!msk->cached_ext;
}
static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
sock_owned_by_me(sk);
mptcp_for_each_subflow(msk, subflow) {
if (subflow->data_avail)
return mptcp_subflow_tcp_sock(subflow);
}
return NULL;
}
static bool mptcp_skb_can_collapse_to(u64 write_seq,
const struct sk_buff *skb,
const struct mptcp_ext *mpext)
{
if (!tcp_skb_can_collapse_to(skb))
return false;
/* can collapse only if MPTCP level sequence is in order */
return mpext && mpext->data_seq + mpext->data_len == write_seq;
}
static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk,
const struct page_frag *pfrag,
const struct mptcp_data_frag *df)
{
return df && pfrag->page == df->page &&
df->data_seq + df->data_len == msk->write_seq;
}
static void dfrag_uncharge(struct sock *sk, int len)
{
sk_mem_uncharge(sk, len);
sk_wmem_queued_add(sk, -len);
}
static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag)
{
int len = dfrag->data_len + dfrag->overhead;
list_del(&dfrag->list);
dfrag_uncharge(sk, len);
put_page(dfrag->page);
}
static void mptcp_clean_una(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct mptcp_data_frag *dtmp, *dfrag;
u64 snd_una = atomic64_read(&msk->snd_una);
bool cleaned = false;
list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
break;
dfrag_clear(sk, dfrag);
cleaned = true;
}
dfrag = mptcp_rtx_head(sk);
if (dfrag && after64(snd_una, dfrag->data_seq)) {
u64 delta = dfrag->data_seq + dfrag->data_len - snd_una;
dfrag->data_seq += delta;
dfrag->data_len -= delta;
dfrag_uncharge(sk, delta);
cleaned = true;
}
if (cleaned) {
sk_mem_reclaim_partial(sk);
/* Only wake up writers if a subflow is ready */
if (test_bit(MPTCP_SEND_SPACE, &msk->flags))
sk_stream_write_space(sk);
}
}
/* ensure we get enough memory for the frag hdr, beyond some minimal amount of
* data
*/
static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
{
if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag),
pfrag, sk->sk_allocation)))
return true;
sk->sk_prot->enter_memory_pressure(sk);
sk_stream_moderate_sndbuf(sk);
return false;
}
static struct mptcp_data_frag *
mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag,
int orig_offset)
{
int offset = ALIGN(orig_offset, sizeof(long));
struct mptcp_data_frag *dfrag;
dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset);
dfrag->data_len = 0;
dfrag->data_seq = msk->write_seq;
dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag);
dfrag->offset = offset + sizeof(struct mptcp_data_frag);
dfrag->page = pfrag->page;
return dfrag;
}
static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
struct msghdr *msg, struct mptcp_data_frag *dfrag,
long *timeo, int *pmss_now,
int *ps_goal)
{
int mss_now, avail_size, size_goal, offset, ret, frag_truesize = 0;
bool dfrag_collapsed, can_collapse = false;
struct mptcp_sock *msk = mptcp_sk(sk);
struct mptcp_ext *mpext = NULL;
bool retransmission = !!dfrag;
struct sk_buff *skb, *tail;
struct page_frag *pfrag;
struct page *page;
u64 *write_seq;
size_t psize;
/* use the mptcp page cache so that we can easily move the data
* from one substream to another, but do per subflow memory accounting
* Note: pfrag is used only !retransmission, but the compiler if
* fooled into a warning if we don't init here
*/
pfrag = sk_page_frag(sk);
while ((!retransmission && !mptcp_page_frag_refill(ssk, pfrag)) ||
!mptcp_ext_cache_refill(msk)) {
ret = sk_stream_wait_memory(ssk, timeo);
if (ret)
return ret;
/* if sk_stream_wait_memory() sleeps snd_una can change
* significantly, refresh the rtx queue
*/
mptcp_clean_una(sk);
if (unlikely(__mptcp_needs_tcp_fallback(msk)))
return 0;
}
if (!retransmission) {
write_seq = &msk->write_seq;
page = pfrag->page;
} else {
write_seq = &dfrag->data_seq;
page = dfrag->page;
}
/* compute copy limit */
mss_now = tcp_send_mss(ssk, &size_goal, msg->msg_flags);
*pmss_now = mss_now;
*ps_goal = size_goal;
avail_size = size_goal;
skb = tcp_write_queue_tail(ssk);
if (skb) {
mpext = skb_ext_find(skb, SKB_EXT_MPTCP);
/* Limit the write to the size available in the
* current skb, if any, so that we create at most a new skb.
* Explicitly tells TCP internals to avoid collapsing on later
* queue management operation, to avoid breaking the ext <->
* SSN association set here
*/
can_collapse = (size_goal - skb->len > 0) &&
mptcp_skb_can_collapse_to(*write_seq, skb, mpext);
if (!can_collapse)
TCP_SKB_CB(skb)->eor = 1;
else
avail_size = size_goal - skb->len;
}
if (!retransmission) {
/* reuse tail pfrag, if possible, or carve a new one from the
* page allocator
*/
dfrag = mptcp_rtx_tail(sk);
offset = pfrag->offset;
dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag);
if (!dfrag_collapsed) {
dfrag = mptcp_carve_data_frag(msk, pfrag, offset);
offset = dfrag->offset;
frag_truesize = dfrag->overhead;
}
psize = min_t(size_t, pfrag->size - offset, avail_size);
/* Copy to page */
pr_debug("left=%zu", msg_data_left(msg));
psize = copy_page_from_iter(pfrag->page, offset,
min_t(size_t, msg_data_left(msg),
psize),
&msg->msg_iter);
pr_debug("left=%zu", msg_data_left(msg));
if (!psize)
return -EINVAL;
if (!sk_wmem_schedule(sk, psize + dfrag->overhead))
return -ENOMEM;
} else {
offset = dfrag->offset;
psize = min_t(size_t, dfrag->data_len, avail_size);
}
/* tell the TCP stack to delay the push so that we can safely
* access the skb after the sendpages call
*/
ret = do_tcp_sendpages(ssk, page, offset, psize,
msg->msg_flags | MSG_SENDPAGE_NOTLAST);
if (ret <= 0)
return ret;
frag_truesize += ret;
if (!retransmission) {
if (unlikely(ret < psize))
iov_iter_revert(&msg->msg_iter, psize - ret);
/* send successful, keep track of sent data for mptcp-level
* retransmission
*/
dfrag->data_len += ret;
if (!dfrag_collapsed) {
get_page(dfrag->page);
list_add_tail(&dfrag->list, &msk->rtx_queue);
sk_wmem_queued_add(sk, frag_truesize);
} else {
sk_wmem_queued_add(sk, ret);
}
/* charge data on mptcp rtx queue to the master socket
* Note: we charge such data both to sk and ssk
*/
sk->sk_forward_alloc -= frag_truesize;
}
/* if the tail skb extension is still the cached one, collapsing
* really happened. Note: we can't check for 'same skb' as the sk_buff
* hdr on tail can be transmitted, freed and re-allocated by the
* do_tcp_sendpages() call
*/
tail = tcp_write_queue_tail(ssk);
if (mpext && tail && mpext == skb_ext_find(tail, SKB_EXT_MPTCP)) {
WARN_ON_ONCE(!can_collapse);
mpext->data_len += ret;
goto out;
}
skb = tcp_write_queue_tail(ssk);
mpext = __skb_ext_set(skb, SKB_EXT_MPTCP, msk->cached_ext);
msk->cached_ext = NULL;
memset(mpext, 0, sizeof(*mpext));
mpext->data_seq = *write_seq;
mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq;
mpext->data_len = ret;
mpext->use_map = 1;
mpext->dsn64 = 1;
pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d",
mpext->data_seq, mpext->subflow_seq, mpext->data_len,
mpext->dsn64);
out:
if (!retransmission)
pfrag->offset += frag_truesize;
*write_seq += ret;
mptcp_subflow_ctx(ssk)->rel_write_seq += ret;
return ret;
}
static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow;
struct sock *backup = NULL;
sock_owned_by_me((const struct sock *)msk);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
if (!sk_stream_memory_free(ssk)) {
struct socket *sock = ssk->sk_socket;
if (sock) {
clear_bit(MPTCP_SEND_SPACE, &msk->flags);
smp_mb__after_atomic();
/* enables sk->write_space() callbacks */
set_bit(SOCK_NOSPACE, &sock->flags);
}
return NULL;
}
if (subflow->backup) {
if (!backup)
backup = ssk;
continue;
}
return ssk;
}
return backup;
}
static void ssk_check_wmem(struct mptcp_sock *msk, struct sock *ssk)
{
struct socket *sock;
if (likely(sk_stream_is_writeable(ssk)))
return;
sock = READ_ONCE(ssk->sk_socket);
if (sock) {
clear_bit(MPTCP_SEND_SPACE, &msk->flags);
smp_mb__after_atomic();
/* set NOSPACE only after clearing SEND_SPACE flag */
set_bit(SOCK_NOSPACE, &sock->flags);
}
}
static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
{
int mss_now = 0, size_goal = 0, ret = 0;
struct mptcp_sock *msk = mptcp_sk(sk);
struct socket *ssock;
size_t copied = 0;
struct sock *ssk;
long timeo;
if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL))
return -EOPNOTSUPP;
lock_sock(sk);
timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
ret = sk_stream_wait_connect(sk, &timeo);
if (ret)
goto out;
}
fallback:
ssock = __mptcp_tcp_fallback(msk);
if (unlikely(ssock)) {
release_sock(sk);
pr_debug("fallback passthrough");
ret = sock_sendmsg(ssock, msg);
return ret >= 0 ? ret + copied : (copied ? copied : ret);
}
mptcp_clean_una(sk);
__mptcp_flush_join_list(msk);
ssk = mptcp_subflow_get_send(msk);
while (!sk_stream_memory_free(sk) || !ssk) {
ret = sk_stream_wait_memory(sk, &timeo);
if (ret)
goto out;
mptcp_clean_una(sk);
ssk = mptcp_subflow_get_send(msk);
if (list_empty(&msk->conn_list)) {
ret = -ENOTCONN;
goto out;
}
}
pr_debug("conn_list->subflow=%p", ssk);
lock_sock(ssk);
while (msg_data_left(msg)) {
ret = mptcp_sendmsg_frag(sk, ssk, msg, NULL, &timeo, &mss_now,
&size_goal);
if (ret < 0)
break;
if (ret == 0 && unlikely(__mptcp_needs_tcp_fallback(msk))) {
/* Can happen for passive sockets:
* 3WHS negotiated MPTCP, but first packet after is
* plain TCP (e.g. due to middlebox filtering unknown
* options).
*
* Fall back to TCP.
*/
release_sock(ssk);
goto fallback;
}
copied += ret;
}
mptcp_set_timeout(sk, ssk);
if (copied) {
ret = copied;
tcp_push(ssk, msg->msg_flags, mss_now, tcp_sk(ssk)->nonagle,
size_goal);
/* start the timer, if it's not pending */
if (!mptcp_timer_pending(sk))
mptcp_reset_timer(sk);
}
ssk_check_wmem(msk, ssk);
release_sock(ssk);
out:
release_sock(sk);
return ret;
}
static void mptcp_wait_data(struct sock *sk, long *timeo)
{
DEFINE_WAIT_FUNC(wait, woken_wake_function);
struct mptcp_sock *msk = mptcp_sk(sk);
add_wait_queue(sk_sleep(sk), &wait);
sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
sk_wait_event(sk, timeo,
test_and_clear_bit(MPTCP_DATA_READY, &msk->flags), &wait);
sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
remove_wait_queue(sk_sleep(sk), &wait);
}
static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
struct msghdr *msg,
size_t len)
{
struct sock *sk = (struct sock *)msk;
struct sk_buff *skb;
int copied = 0;
while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
u32 offset = MPTCP_SKB_CB(skb)->offset;
u32 data_len = skb->len - offset;
u32 count = min_t(size_t, len - copied, data_len);
int err;
err = skb_copy_datagram_msg(skb, offset, msg, count);
if (unlikely(err < 0)) {
if (!copied)
return err;
break;
}
copied += count;
if (count < data_len) {
MPTCP_SKB_CB(skb)->offset += count;
break;
}
__skb_unlink(skb, &sk->sk_receive_queue);
__kfree_skb(skb);
if (copied >= len)
break;
}
return copied;
}
static bool __mptcp_move_skbs(struct mptcp_sock *msk)
{
unsigned int moved = 0;
bool done;
do {
struct sock *ssk = mptcp_subflow_recv_lookup(msk);
if (!ssk)
break;
lock_sock(ssk);
done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
release_sock(ssk);
} while (!done);
return moved > 0;
}
static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
int nonblock, int flags, int *addr_len)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct socket *ssock;
int copied = 0;
int target;
long timeo;
if (msg->msg_flags & ~(MSG_WAITALL | MSG_DONTWAIT))
return -EOPNOTSUPP;
lock_sock(sk);
ssock = __mptcp_tcp_fallback(msk);
if (unlikely(ssock)) {
fallback:
release_sock(sk);
pr_debug("fallback-read subflow=%p",
mptcp_subflow_ctx(ssock->sk));
copied = sock_recvmsg(ssock, msg, flags);
return copied;
}
timeo = sock_rcvtimeo(sk, nonblock);
len = min_t(size_t, len, INT_MAX);
target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
__mptcp_flush_join_list(msk);
while (len > (size_t)copied) {
int bytes_read;
bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied);
if (unlikely(bytes_read < 0)) {
if (!copied)
copied = bytes_read;
goto out_err;
}
copied += bytes_read;
if (skb_queue_empty(&sk->sk_receive_queue) &&
__mptcp_move_skbs(msk))
continue;
/* only the master socket status is relevant here. The exit
* conditions mirror closely tcp_recvmsg()
*/
if (copied >= target)
break;
if (copied) {
if (sk->sk_err ||
sk->sk_state == TCP_CLOSE ||
(sk->sk_shutdown & RCV_SHUTDOWN) ||
!timeo ||
signal_pending(current))
break;
} else {
if (sk->sk_err) {
copied = sock_error(sk);
break;
}
if (sk->sk_shutdown & RCV_SHUTDOWN)
break;
if (sk->sk_state == TCP_CLOSE) {
copied = -ENOTCONN;
break;
}
if (!timeo) {
copied = -EAGAIN;
break;
}
if (signal_pending(current)) {
copied = sock_intr_errno(timeo);
break;
}
}
pr_debug("block timeout %ld", timeo);
mptcp_wait_data(sk, &timeo);
ssock = __mptcp_tcp_fallback(msk);
if (unlikely(ssock))
goto fallback;
}
if (skb_queue_empty(&sk->sk_receive_queue)) {
/* entire backlog drained, clear DATA_READY. */
clear_bit(MPTCP_DATA_READY, &msk->flags);
/* .. race-breaker: ssk might have gotten new data
* after last __mptcp_move_skbs() returned false.
*/
if (unlikely(__mptcp_move_skbs(msk)))
set_bit(MPTCP_DATA_READY, &msk->flags);
} else if (unlikely(!test_bit(MPTCP_DATA_READY, &msk->flags))) {
/* data to read but mptcp_wait_data() cleared DATA_READY */
set_bit(MPTCP_DATA_READY, &msk->flags);
}
out_err:
release_sock(sk);
return copied;
}
static void mptcp_retransmit_handler(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
if (atomic64_read(&msk->snd_una) == msk->write_seq) {
mptcp_stop_timer(sk);
} else {
set_bit(MPTCP_WORK_RTX, &msk->flags);
if (schedule_work(&msk->work))
sock_hold(sk);
}
}
static void mptcp_retransmit_timer(struct timer_list *t)
{
struct inet_connection_sock *icsk = from_timer(icsk, t,
icsk_retransmit_timer);
struct sock *sk = &icsk->icsk_inet.sk;
bh_lock_sock(sk);
if (!sock_owned_by_user(sk)) {
mptcp_retransmit_handler(sk);
} else {
/* delegate our work to tcp_release_cb() */
if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED,
&sk->sk_tsq_flags))
sock_hold(sk);
}
bh_unlock_sock(sk);
sock_put(sk);
}
/* Find an idle subflow. Return NULL if there is unacked data at tcp
* level.
*
* A backup subflow is returned only if that is the only kind available.
*/
static struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow;
struct sock *backup = NULL;
sock_owned_by_me((const struct sock *)msk);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
/* still data outstanding at TCP level? Don't retransmit. */
if (!tcp_write_queue_empty(ssk))
return NULL;
if (subflow->backup) {
if (!backup)
backup = ssk;
continue;
}
return ssk;
}
return backup;
}
/* subflow sockets can be either outgoing (connect) or incoming
* (accept).
*
* Outgoing subflows use in-kernel sockets.
* Incoming subflows do not have their own 'struct socket' allocated,
* so we need to use tcp_close() after detaching them from the mptcp
* parent socket.
*/
static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
struct mptcp_subflow_context *subflow,
long timeout)
{
struct socket *sock = READ_ONCE(ssk->sk_socket);
list_del(&subflow->node);
if (sock && sock != sk->sk_socket) {
/* outgoing subflow */
sock_release(sock);
} else {
/* incoming subflow */
tcp_close(ssk, timeout);
}
}
static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
{
return 0;
}
static void mptcp_check_for_eof(struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
int receivers = 0;
mptcp_for_each_subflow(msk, subflow)
receivers += !subflow->rx_eof;
if (!receivers && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
/* hopefully temporary hack: propagate shutdown status
* to msk, when all subflows agree on it
*/
sk->sk_shutdown |= RCV_SHUTDOWN;
smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
set_bit(MPTCP_DATA_READY, &msk->flags);
sk->sk_data_ready(sk);
}
}
static void mptcp_worker(struct work_struct *work)
{
struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
struct sock *ssk, *sk = &msk->sk.icsk_inet.sk;
int orig_len, orig_offset, ret, mss_now = 0, size_goal = 0;
struct mptcp_data_frag *dfrag;
u64 orig_write_seq;
size_t copied = 0;
struct msghdr msg;
long timeo = 0;
lock_sock(sk);
mptcp_clean_una(sk);
__mptcp_flush_join_list(msk);
__mptcp_move_skbs(msk);
if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
mptcp_check_for_eof(msk);
if (!test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
goto unlock;
dfrag = mptcp_rtx_head(sk);
if (!dfrag)
goto unlock;
ssk = mptcp_subflow_get_retrans(msk);
if (!ssk)
goto reset_unlock;
lock_sock(ssk);
msg.msg_flags = MSG_DONTWAIT;
orig_len = dfrag->data_len;
orig_offset = dfrag->offset;
orig_write_seq = dfrag->data_seq;
while (dfrag->data_len > 0) {
ret = mptcp_sendmsg_frag(sk, ssk, &msg, dfrag, &timeo, &mss_now,
&size_goal);
if (ret < 0)
break;
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS);
copied += ret;
dfrag->data_len -= ret;
dfrag->offset += ret;
}
if (copied)
tcp_push(ssk, msg.msg_flags, mss_now, tcp_sk(ssk)->nonagle,
size_goal);
dfrag->data_seq = orig_write_seq;
dfrag->offset = orig_offset;
dfrag->data_len = orig_len;
mptcp_set_timeout(sk, ssk);
release_sock(ssk);
reset_unlock:
if (!mptcp_timer_pending(sk))
mptcp_reset_timer(sk);
unlock:
release_sock(sk);
sock_put(sk);
}
static int __mptcp_init_sock(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
spin_lock_init(&msk->join_list_lock);
INIT_LIST_HEAD(&msk->conn_list);
INIT_LIST_HEAD(&msk->join_list);
INIT_LIST_HEAD(&msk->rtx_queue);
__set_bit(MPTCP_SEND_SPACE, &msk->flags);
INIT_WORK(&msk->work, mptcp_worker);
msk->first = NULL;
inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
mptcp_pm_data_init(msk);
/* re-use the csk retrans timer for MPTCP-level retrans */
timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
return 0;
}
static int mptcp_init_sock(struct sock *sk)
{
struct net *net = sock_net(sk);
int ret;
if (!mptcp_is_enabled(net))
return -ENOPROTOOPT;
if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net))
return -ENOMEM;
ret = __mptcp_init_sock(sk);
if (ret)
return ret;
sk_sockets_allocated_inc(sk);
sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[2];
return 0;
}
static void __mptcp_clear_xmit(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct mptcp_data_frag *dtmp, *dfrag;
sk_stop_timer(sk, &msk->sk.icsk_retransmit_timer);
list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
dfrag_clear(sk, dfrag);
}
static void mptcp_cancel_work(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
if (cancel_work_sync(&msk->work))
sock_put(sk);
}
static void mptcp_subflow_shutdown(struct sock *ssk, int how,
bool data_fin_tx_enable, u64 data_fin_tx_seq)
{
lock_sock(ssk);
switch (ssk->sk_state) {
case TCP_LISTEN:
if (!(how & RCV_SHUTDOWN))
break;
/* fall through */
case TCP_SYN_SENT:
tcp_disconnect(ssk, O_NONBLOCK);
break;
default:
if (data_fin_tx_enable) {
struct mptcp_subflow_context *subflow;
subflow = mptcp_subflow_ctx(ssk);
subflow->data_fin_tx_seq = data_fin_tx_seq;
subflow->data_fin_tx_enable = 1;
}
ssk->sk_shutdown |= how;
tcp_shutdown(ssk, how);
break;
}
/* Wake up anyone sleeping in poll. */
ssk->sk_state_change(ssk);
release_sock(ssk);
}
/* Called with msk lock held, releases such lock before returning */
static void mptcp_close(struct sock *sk, long timeout)
{
struct mptcp_subflow_context *subflow, *tmp;
struct mptcp_sock *msk = mptcp_sk(sk);
LIST_HEAD(conn_list);
u64 data_fin_tx_seq;
lock_sock(sk);
mptcp_token_destroy(msk->token);
inet_sk_state_store(sk, TCP_CLOSE);
__mptcp_flush_join_list(msk);
list_splice_init(&msk->conn_list, &conn_list);
data_fin_tx_seq = msk->write_seq;
__mptcp_clear_xmit(sk);
release_sock(sk);
list_for_each_entry_safe(subflow, tmp, &conn_list, node) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
subflow->data_fin_tx_seq = data_fin_tx_seq;
subflow->data_fin_tx_enable = 1;
__mptcp_close_ssk(sk, ssk, subflow, timeout);
}
mptcp_cancel_work(sk);
mptcp_pm_close(msk);
__skb_queue_purge(&sk->sk_receive_queue);
sk_common_release(sk);
}
static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk)
{
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
const struct ipv6_pinfo *ssk6 = inet6_sk(ssk);
struct ipv6_pinfo *msk6 = inet6_sk(msk);
msk->sk_v6_daddr = ssk->sk_v6_daddr;
msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr;
if (msk6 && ssk6) {
msk6->saddr = ssk6->saddr;
msk6->flow_label = ssk6->flow_label;
}
#endif
inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num;
inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport;
inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport;
inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr;
inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr;
inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr;
}
static int mptcp_disconnect(struct sock *sk, int flags)
{
/* Should never be called.
* inet_stream_connect() calls ->disconnect, but that
* refers to the subflow socket, not the mptcp one.
*/
WARN_ON_ONCE(1);
return 0;
}
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
{
unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo);
return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
}
#endif
struct sock *mptcp_sk_clone(const struct sock *sk,
const struct mptcp_options_received *mp_opt,
struct request_sock *req)
{
struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
struct mptcp_sock *msk;
u64 ack_seq;
if (!nsk)
return NULL;
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
if (nsk->sk_family == AF_INET6)
inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
#endif
__mptcp_init_sock(nsk);
msk = mptcp_sk(nsk);
msk->local_key = subflow_req->local_key;
msk->token = subflow_req->token;
msk->subflow = NULL;
if (unlikely(mptcp_token_new_accept(subflow_req->token, nsk))) {
nsk->sk_state = TCP_CLOSE;
bh_unlock_sock(nsk);
/* we can't call into mptcp_close() here - possible BH context
* free the sock directly.
* sk_clone_lock() sets nsk refcnt to two, hence call sk_free()
* too.
*/
sk_common_release(nsk);
sk_free(nsk);
return NULL;
}
msk->write_seq = subflow_req->idsn + 1;
atomic64_set(&msk->snd_una, msk->write_seq);
if (mp_opt->mp_capable) {
msk->can_ack = true;
msk->remote_key = mp_opt->sndr_key;
mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
ack_seq++;
msk->ack_seq = ack_seq;
}
sock_reset_flag(nsk, SOCK_RCU_FREE);
/* will be fully established after successful MPC subflow creation */
inet_sk_state_store(nsk, TCP_SYN_RECV);
bh_unlock_sock(nsk);
/* keep a single reference */
__sock_put(nsk);
return nsk;
}
static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
bool kern)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct socket *listener;
struct sock *newsk;
listener = __mptcp_nmpc_socket(msk);
if (WARN_ON_ONCE(!listener)) {
*err = -EINVAL;
return NULL;
}
pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk));
newsk = inet_csk_accept(listener->sk, flags, err, kern);
if (!newsk)
return NULL;
pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk));
if (sk_is_mptcp(newsk)) {
struct mptcp_subflow_context *subflow;
struct sock *new_mptcp_sock;
struct sock *ssk = newsk;
subflow = mptcp_subflow_ctx(newsk);
new_mptcp_sock = subflow->conn;
/* is_mptcp should be false if subflow->conn is missing, see
* subflow_syn_recv_sock()
*/
if (WARN_ON_ONCE(!new_mptcp_sock)) {
tcp_sk(newsk)->is_mptcp = 0;
return newsk;
}
/* acquire the 2nd reference for the owning socket */
sock_hold(new_mptcp_sock);
local_bh_disable();
bh_lock_sock(new_mptcp_sock);
msk = mptcp_sk(new_mptcp_sock);
msk->first = newsk;
newsk = new_mptcp_sock;
mptcp_copy_inaddrs(newsk, ssk);
list_add(&subflow->node, &msk->conn_list);
inet_sk_state_store(newsk, TCP_ESTABLISHED);
bh_unlock_sock(new_mptcp_sock);
__MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
local_bh_enable();
} else {
MPTCP_INC_STATS(sock_net(sk),
MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK);
}
return newsk;
}
static void mptcp_destroy(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
if (msk->cached_ext)
__skb_ext_put(msk->cached_ext);
sk_sockets_allocated_dec(sk);
}
static int mptcp_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, unsigned int optlen)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct socket *ssock;
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 TCP socket options are passed through
* to the one remaining subflow.
*/
lock_sock(sk);
ssock = __mptcp_tcp_fallback(msk);
release_sock(sk);
if (ssock)
return tcp_setsockopt(ssock->sk, level, optname, optval,
optlen);
return -EOPNOTSUPP;
}
static int mptcp_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *option)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct socket *ssock;
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);
ssock = __mptcp_tcp_fallback(msk);
release_sock(sk);
if (ssock)
return tcp_getsockopt(ssock->sk, level, optname, optval,
option);
return -EOPNOTSUPP;
}
#define MPTCP_DEFERRED_ALL (TCPF_DELACK_TIMER_DEFERRED | \
TCPF_WRITE_TIMER_DEFERRED)
/* this is very alike tcp_release_cb() but we must handle differently a
* different set of events
*/
static void mptcp_release_cb(struct sock *sk)
{
unsigned long flags, nflags;
do {
flags = sk->sk_tsq_flags;
if (!(flags & MPTCP_DEFERRED_ALL))
return;
nflags = flags & ~MPTCP_DEFERRED_ALL;
} while (cmpxchg(&sk->sk_tsq_flags, flags, nflags) != flags);
sock_release_ownership(sk);
if (flags & TCPF_DELACK_TIMER_DEFERRED) {
struct mptcp_sock *msk = mptcp_sk(sk);
struct sock *ssk;
ssk = mptcp_subflow_recv_lookup(msk);
if (!ssk || !schedule_work(&msk->work))
__sock_put(sk);
}
if (flags & TCPF_WRITE_TIMER_DEFERRED) {
mptcp_retransmit_handler(sk);
__sock_put(sk);
}
}
static int mptcp_get_port(struct sock *sk, unsigned short snum)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct socket *ssock;
ssock = __mptcp_nmpc_socket(msk);
pr_debug("msk=%p, subflow=%p", msk, ssock);
if (WARN_ON_ONCE(!ssock))
return -EINVAL;
return inet_csk_get_port(ssock->sk, snum);
}
void mptcp_finish_connect(struct sock *ssk)
{
struct mptcp_subflow_context *subflow;
struct mptcp_sock *msk;
struct sock *sk;
u64 ack_seq;
subflow = mptcp_subflow_ctx(ssk);
sk = subflow->conn;
msk = mptcp_sk(sk);
if (!subflow->mp_capable) {
MPTCP_INC_STATS(sock_net(sk),
MPTCP_MIB_MPCAPABLEACTIVEFALLBACK);
return;
}
pr_debug("msk=%p, token=%u", sk, subflow->token);
mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq);
ack_seq++;
subflow->map_seq = ack_seq;
subflow->map_subflow_seq = 1;
subflow->rel_write_seq = 1;
/* the socket is not connected yet, no msk/subflow ops can access/race
* accessing the field below
*/
WRITE_ONCE(msk->remote_key, subflow->remote_key);
WRITE_ONCE(msk->local_key, subflow->local_key);
WRITE_ONCE(msk->token, subflow->token);
WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
WRITE_ONCE(msk->ack_seq, ack_seq);
WRITE_ONCE(msk->can_ack, 1);
atomic64_set(&msk->snd_una, msk->write_seq);
mptcp_pm_new_connection(msk, 0);
}
static void mptcp_sock_graft(struct sock *sk, struct socket *parent)
{
write_lock_bh(&sk->sk_callback_lock);
rcu_assign_pointer(sk->sk_wq, &parent->wq);
sk_set_socket(sk, parent);
sk->sk_uid = SOCK_INODE(parent)->i_uid;
write_unlock_bh(&sk->sk_callback_lock);
}
bool mptcp_finish_join(struct sock *sk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
struct sock *parent = (void *)msk;
struct socket *parent_sock;
bool ret;
pr_debug("msk=%p, subflow=%p", msk, subflow);
/* mptcp socket already closing? */
if (inet_sk_state_load(parent) != TCP_ESTABLISHED)
return false;
if (!msk->pm.server_side)
return true;
/* passive connection, attach to msk socket */
parent_sock = READ_ONCE(parent->sk_socket);
if (parent_sock && !sk->sk_socket)
mptcp_sock_graft(sk, parent_sock);
ret = mptcp_pm_allow_new_subflow(msk);
if (ret) {
subflow->map_seq = msk->ack_seq;
/* active connections are already on conn_list */
spin_lock_bh(&msk->join_list_lock);
if (!WARN_ON_ONCE(!list_empty(&subflow->node)))
list_add_tail(&subflow->node, &msk->join_list);
spin_unlock_bh(&msk->join_list_lock);
}
return ret;
}
bool mptcp_sk_is_subflow(const struct sock *sk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
return subflow->mp_join == 1;
}
static bool mptcp_memory_free(const struct sock *sk, int wake)
{
struct mptcp_sock *msk = mptcp_sk(sk);
return wake ? test_bit(MPTCP_SEND_SPACE, &msk->flags) : true;
}
static struct proto mptcp_prot = {
.name = "MPTCP",
.owner = THIS_MODULE,
.init = mptcp_init_sock,
.disconnect = mptcp_disconnect,
.close = mptcp_close,
.accept = mptcp_accept,
.setsockopt = mptcp_setsockopt,
.getsockopt = mptcp_getsockopt,
.shutdown = tcp_shutdown,
.destroy = mptcp_destroy,
.sendmsg = mptcp_sendmsg,
.recvmsg = mptcp_recvmsg,
.release_cb = mptcp_release_cb,
.hash = inet_hash,
.unhash = inet_unhash,
.get_port = mptcp_get_port,
.sockets_allocated = &mptcp_sockets_allocated,
.memory_allocated = &tcp_memory_allocated,
.memory_pressure = &tcp_memory_pressure,
.stream_memory_free = mptcp_memory_free,
.sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
.sysctl_mem = sysctl_tcp_mem,
.obj_size = sizeof(struct mptcp_sock),
.no_autobind = true,
};
static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
struct mptcp_sock *msk = mptcp_sk(sock->sk);
struct socket *ssock;
int err;
lock_sock(sock->sk);
ssock = __mptcp_socket_create(msk, MPTCP_SAME_STATE);
if (IS_ERR(ssock)) {
err = PTR_ERR(ssock);
goto unlock;
}
err = ssock->ops->bind(ssock, uaddr, addr_len);
if (!err)
mptcp_copy_inaddrs(sock->sk, ssock->sk);
unlock:
release_sock(sock->sk);
return err;
}
static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
int addr_len, int flags)
{
struct mptcp_sock *msk = mptcp_sk(sock->sk);
struct socket *ssock;
int err;
lock_sock(sock->sk);
if (sock->state != SS_UNCONNECTED && msk->subflow) {
/* pending connection or invalid state, let existing subflow
* cope with that
*/
ssock = msk->subflow;
goto do_connect;
}
ssock = __mptcp_socket_create(msk, TCP_SYN_SENT);
if (IS_ERR(ssock)) {
err = PTR_ERR(ssock);
goto unlock;
}
#ifdef CONFIG_TCP_MD5SIG
/* no MPTCP if MD5SIG is enabled on this socket or we may run out of
* TCP option space.
*/
if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))
mptcp_subflow_ctx(ssock->sk)->request_mptcp = 0;
#endif
do_connect:
err = ssock->ops->connect(ssock, uaddr, addr_len, flags);
sock->state = ssock->state;
/* on successful connect, the msk state will be moved to established by
* subflow_finish_connect()
*/
if (!err || err == EINPROGRESS)
mptcp_copy_inaddrs(sock->sk, ssock->sk);
else
inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
unlock:
release_sock(sock->sk);
return err;
}
static int mptcp_v4_getname(struct socket *sock, struct sockaddr *uaddr,
int peer)
{
if (sock->sk->sk_prot == &tcp_prot) {
/* we are being invoked from __sys_accept4, after
* mptcp_accept() has just accepted a non-mp-capable
* flow: sk is a tcp_sk, not an mptcp one.
*
* Hand the socket over to tcp so all further socket ops
* bypass mptcp.
*/
sock->ops = &inet_stream_ops;
}
return inet_getname(sock, uaddr, peer);
}
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
static int mptcp_v6_getname(struct socket *sock, struct sockaddr *uaddr,
int peer)
{
if (sock->sk->sk_prot == &tcpv6_prot) {
/* we are being invoked from __sys_accept4 after
* mptcp_accept() has accepted a non-mp-capable
* subflow: sk is a tcp_sk, not mptcp.
*
* Hand the socket over to tcp so all further
* socket ops bypass mptcp.
*/
sock->ops = &inet6_stream_ops;
}
return inet6_getname(sock, uaddr, peer);
}
#endif
static int mptcp_listen(struct socket *sock, int backlog)
{
struct mptcp_sock *msk = mptcp_sk(sock->sk);
struct socket *ssock;
int err;
pr_debug("msk=%p", msk);
lock_sock(sock->sk);
ssock = __mptcp_socket_create(msk, TCP_LISTEN);
if (IS_ERR(ssock)) {
err = PTR_ERR(ssock);
goto unlock;
}
sock_set_flag(sock->sk, SOCK_RCU_FREE);
err = ssock->ops->listen(ssock, backlog);
inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
if (!err)
mptcp_copy_inaddrs(sock->sk, ssock->sk);
unlock:
release_sock(sock->sk);
return err;
}
static bool is_tcp_proto(const struct proto *p)
{
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
return p == &tcp_prot || p == &tcpv6_prot;
#else
return p == &tcp_prot;
#endif
}
static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
int flags, bool kern)
{
struct mptcp_sock *msk = mptcp_sk(sock->sk);
struct socket *ssock;
int err;
pr_debug("msk=%p", msk);
lock_sock(sock->sk);
if (sock->sk->sk_state != TCP_LISTEN)
goto unlock_fail;
ssock = __mptcp_nmpc_socket(msk);
if (!ssock)
goto unlock_fail;
sock_hold(ssock->sk);
release_sock(sock->sk);
err = ssock->ops->accept(sock, newsock, flags, kern);
if (err == 0 && !is_tcp_proto(newsock->sk->sk_prot)) {
struct mptcp_sock *msk = mptcp_sk(newsock->sk);
struct mptcp_subflow_context *subflow;
/* set ssk->sk_socket of accept()ed flows to mptcp socket.
* This is needed so NOSPACE flag can be set from tcp stack.
*/
__mptcp_flush_join_list(msk);
list_for_each_entry(subflow, &msk->conn_list, node) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
if (!ssk->sk_socket)
mptcp_sock_graft(ssk, newsock);
}
}
sock_put(ssock->sk);
return err;
unlock_fail:
release_sock(sock->sk);
return -EINVAL;
}
static __poll_t mptcp_poll(struct file *file, struct socket *sock,
struct poll_table_struct *wait)
{
struct sock *sk = sock->sk;
struct mptcp_sock *msk;
struct socket *ssock;
__poll_t mask = 0;
msk = mptcp_sk(sk);
lock_sock(sk);
ssock = __mptcp_tcp_fallback(msk);
if (!ssock)
ssock = __mptcp_nmpc_socket(msk);
if (ssock) {
mask = ssock->ops->poll(file, ssock, wait);
release_sock(sk);
return mask;
}
release_sock(sk);
sock_poll_wait(file, sock, wait);
lock_sock(sk);
if (test_bit(MPTCP_DATA_READY, &msk->flags))
mask = EPOLLIN | EPOLLRDNORM;
if (sk_stream_is_writeable(sk) &&
test_bit(MPTCP_SEND_SPACE, &msk->flags))
mask |= EPOLLOUT | EPOLLWRNORM;
if (sk->sk_shutdown & RCV_SHUTDOWN)
mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
release_sock(sk);
return mask;
}
static int mptcp_shutdown(struct socket *sock, int how)
{
struct mptcp_sock *msk = mptcp_sk(sock->sk);
struct mptcp_subflow_context *subflow;
struct socket *ssock;
int ret = 0;
pr_debug("sk=%p, how=%d", msk, how);
lock_sock(sock->sk);
ssock = __mptcp_tcp_fallback(msk);
if (ssock) {
release_sock(sock->sk);
return inet_shutdown(ssock, how);
}
if (how == SHUT_WR || how == SHUT_RDWR)
inet_sk_state_store(sock->sk, TCP_FIN_WAIT1);
how++;
if ((how & ~SHUTDOWN_MASK) || !how) {
ret = -EINVAL;
goto out_unlock;
}
if (sock->state == SS_CONNECTING) {
if ((1 << sock->sk->sk_state) &
(TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE))
sock->state = SS_DISCONNECTING;
else
sock->state = SS_CONNECTED;
}
__mptcp_flush_join_list(msk);
mptcp_for_each_subflow(msk, subflow) {
struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
mptcp_subflow_shutdown(tcp_sk, how, 1, msk->write_seq);
}
out_unlock:
release_sock(sock->sk);
return ret;
}
static const struct proto_ops mptcp_stream_ops = {
.family = PF_INET,
.owner = THIS_MODULE,
.release = inet_release,
.bind = mptcp_bind,
.connect = mptcp_stream_connect,
.socketpair = sock_no_socketpair,
.accept = mptcp_stream_accept,
.getname = mptcp_v4_getname,
.poll = mptcp_poll,
.ioctl = inet_ioctl,
.gettstamp = sock_gettstamp,
.listen = mptcp_listen,
.shutdown = mptcp_shutdown,
.setsockopt = sock_common_setsockopt,
.getsockopt = sock_common_getsockopt,
.sendmsg = inet_sendmsg,
.recvmsg = inet_recvmsg,
.mmap = sock_no_mmap,
.sendpage = inet_sendpage,
#ifdef CONFIG_COMPAT
.compat_setsockopt = compat_sock_common_setsockopt,
.compat_getsockopt = compat_sock_common_getsockopt,
#endif
};
static struct inet_protosw mptcp_protosw = {
.type = SOCK_STREAM,
.protocol = IPPROTO_MPTCP,
.prot = &mptcp_prot,
.ops = &mptcp_stream_ops,
.flags = INET_PROTOSW_ICSK,
};
void mptcp_proto_init(void)
{
mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL))
panic("Failed to allocate MPTCP pcpu counter\n");
mptcp_subflow_init();
mptcp_pm_init();
if (proto_register(&mptcp_prot, 1) != 0)
panic("Failed to register MPTCP proto.\n");
inet_register_protosw(&mptcp_protosw);
BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb));
}
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
static const struct proto_ops mptcp_v6_stream_ops = {
.family = PF_INET6,
.owner = THIS_MODULE,
.release = inet6_release,
.bind = mptcp_bind,
.connect = mptcp_stream_connect,
.socketpair = sock_no_socketpair,
.accept = mptcp_stream_accept,
.getname = mptcp_v6_getname,
.poll = mptcp_poll,
.ioctl = inet6_ioctl,
.gettstamp = sock_gettstamp,
.listen = mptcp_listen,
.shutdown = mptcp_shutdown,
.setsockopt = sock_common_setsockopt,
.getsockopt = sock_common_getsockopt,
.sendmsg = inet6_sendmsg,
.recvmsg = inet6_recvmsg,
.mmap = sock_no_mmap,
.sendpage = inet_sendpage,
#ifdef CONFIG_COMPAT
.compat_setsockopt = compat_sock_common_setsockopt,
.compat_getsockopt = compat_sock_common_getsockopt,
#endif
};
static struct proto mptcp_v6_prot;
static void mptcp_v6_destroy(struct sock *sk)
{
mptcp_destroy(sk);
inet6_destroy_sock(sk);
}
static struct inet_protosw mptcp_v6_protosw = {
.type = SOCK_STREAM,
.protocol = IPPROTO_MPTCP,
.prot = &mptcp_v6_prot,
.ops = &mptcp_v6_stream_ops,
.flags = INET_PROTOSW_ICSK,
};
int mptcp_proto_v6_init(void)
{
int err;
mptcp_v6_prot = mptcp_prot;
strcpy(mptcp_v6_prot.name, "MPTCPv6");
mptcp_v6_prot.slab = NULL;
mptcp_v6_prot.destroy = mptcp_v6_destroy;
mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock);
err = proto_register(&mptcp_v6_prot, 1);
if (err)
return err;
err = inet6_register_protosw(&mptcp_v6_protosw);
if (err)
proto_unregister(&mptcp_v6_prot);
return err;
}
#endif