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-rw-r--r--net/mptcp/options.c71
1 files changed, 53 insertions, 18 deletions
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 8f940be42f98..7fa822b55c34 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -451,6 +451,8 @@ static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb,
static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow,
struct sk_buff *skb, struct mptcp_ext *ext)
{
+ u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq);
+
if (!ext->use_map || !skb->len) {
/* RFC6824 requires a DSS mapping with specific values
* if DATA_FIN is set but no data payload is mapped
@@ -458,10 +460,13 @@ static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow,
ext->data_fin = 1;
ext->use_map = 1;
ext->dsn64 = 1;
- ext->data_seq = subflow->data_fin_tx_seq;
+ /* The write_seq value has already been incremented, so
+ * the actual sequence number for the DATA_FIN is one less.
+ */
+ ext->data_seq = data_fin_tx_seq - 1;
ext->subflow_seq = 0;
ext->data_len = 1;
- } else if (ext->data_seq + ext->data_len == subflow->data_fin_tx_seq) {
+ } else if (ext->data_seq + ext->data_len == data_fin_tx_seq) {
/* If there's an existing DSS mapping and it is the
* final mapping, DATA_FIN consumes 1 additional byte of
* mapping space.
@@ -477,22 +482,17 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
struct mptcp_out_options *opts)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct mptcp_sock *msk = mptcp_sk(subflow->conn);
unsigned int dss_size = 0;
+ u64 snd_data_fin_enable;
struct mptcp_ext *mpext;
- struct mptcp_sock *msk;
unsigned int ack_size;
bool ret = false;
- u8 tcp_fin;
- if (skb) {
- mpext = mptcp_get_ext(skb);
- tcp_fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
- } else {
- mpext = NULL;
- tcp_fin = 0;
- }
+ mpext = skb ? mptcp_get_ext(skb) : NULL;
+ snd_data_fin_enable = READ_ONCE(msk->snd_data_fin_enable);
- if (!skb || (mpext && mpext->use_map) || tcp_fin) {
+ if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) {
unsigned int map_size;
map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64;
@@ -502,7 +502,7 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
if (mpext)
opts->ext_copy = *mpext;
- if (skb && tcp_fin && subflow->data_fin_tx_enable)
+ if (skb && snd_data_fin_enable)
mptcp_write_data_fin(subflow, skb, &opts->ext_copy);
ret = true;
}
@@ -511,7 +511,6 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
* if the first subflow may have the already the remote key handy
*/
opts->ext_copy.use_ack = 0;
- msk = mptcp_sk(subflow->conn);
if (!READ_ONCE(msk->can_ack)) {
*size = ALIGN(dss_size, 4);
return ret;
@@ -624,6 +623,9 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
opts->suboptions = 0;
+ if (unlikely(mptcp_check_fallback(sk)))
+ return false;
+
if (mptcp_established_options_mp(sk, skb, &opt_size, remaining, opts))
ret = true;
else if (mptcp_established_options_dss(sk, skb, &opt_size, remaining,
@@ -706,6 +708,7 @@ static bool check_fully_established(struct mptcp_sock *msk, struct sock *sk,
* additional ack.
*/
subflow->fully_established = 1;
+ WRITE_ONCE(msk->fully_established, true);
goto fully_established;
}
@@ -714,15 +717,14 @@ static bool check_fully_established(struct mptcp_sock *msk, struct sock *sk,
*/
if (!mp_opt->mp_capable) {
subflow->mp_capable = 0;
- tcp_sk(sk)->is_mptcp = 0;
+ pr_fallback(msk);
+ __mptcp_do_fallback(msk);
return false;
}
if (unlikely(!READ_ONCE(msk->pm.server_side)))
pr_warn_once("bogus mpc option on established client sk");
- subflow->fully_established = 1;
- subflow->remote_key = mp_opt->sndr_key;
- subflow->can_ack = 1;
+ mptcp_subflow_fully_established(subflow, mp_opt);
fully_established:
if (likely(subflow->pm_notified))
@@ -780,6 +782,22 @@ static void update_una(struct mptcp_sock *msk,
}
}
+bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq)
+{
+ /* Skip if DATA_FIN was already received.
+ * If updating simultaneously with the recvmsg loop, values
+ * should match. If they mismatch, the peer is misbehaving and
+ * we will prefer the most recent information.
+ */
+ if (READ_ONCE(msk->rcv_data_fin) || !READ_ONCE(msk->first))
+ return false;
+
+ WRITE_ONCE(msk->rcv_data_fin_seq, data_fin_seq);
+ WRITE_ONCE(msk->rcv_data_fin, 1);
+
+ return true;
+}
+
static bool add_addr_hmac_valid(struct mptcp_sock *msk,
struct mptcp_options_received *mp_opt)
{
@@ -814,6 +832,9 @@ void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb,
struct mptcp_options_received mp_opt;
struct mptcp_ext *mpext;
+ if (__mptcp_check_fallback(msk))
+ return;
+
mptcp_get_options(skb, &mp_opt);
if (!check_fully_established(msk, sk, subflow, skb, &mp_opt))
return;
@@ -847,6 +868,20 @@ void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb,
if (mp_opt.use_ack)
update_una(msk, &mp_opt);
+ /* Zero-data-length packets are dropped by the caller and not
+ * propagated to the MPTCP layer, so the skb extension does not
+ * need to be allocated or populated. DATA_FIN information, if
+ * present, needs to be updated here before the skb is freed.
+ */
+ if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {
+ if (mp_opt.data_fin && mp_opt.data_len == 1 &&
+ mptcp_update_rcv_data_fin(msk, mp_opt.data_seq) &&
+ schedule_work(&msk->work))
+ sock_hold(subflow->conn);
+
+ return;
+ }
+
mpext = skb_ext_add(skb, SKB_EXT_MPTCP);
if (!mpext)
return;