diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index b6c62d2943805c52411d7d0c881831dee5905577..4e90e6ae79df71831855fe2aa90fb18399977e2b 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -106,6 +106,16 @@ enum {
#define TCP_THIN_LINEAR_TIMEOUTS 16 /* Use linear timeouts for thin streams*/
#define TCP_THIN_DUPACK 17 /* Fast retrans. after 1 dupack */
#define TCP_USER_TIMEOUT 18 /* How long for loss retry before timeout */
+#define TCP_REPAIR 19 /* TCP sock is under repair right now */
+#define TCP_REPAIR_QUEUE 20
+#define TCP_QUEUE_SEQ 21
+
+enum {
+ TCP_NO_QUEUE,
+ TCP_RECV_QUEUE,
+ TCP_SEND_QUEUE,
+ TCP_QUEUES_NR,
+};
/* for TCP_INFO socket option */
#define TCPI_OPT_TIMESTAMPS 1
@@ -353,7 +363,9 @@ struct tcp_sock {
u8 nonagle : 4,/* Disable Nagle algorithm? */
thin_lto : 1,/* Use linear timeouts for thin streams */
thin_dupack : 1,/* Fast retransmit on first dupack */
- unused : 2;
+ repair : 1,
+ unused : 1;
+ u8 repair_queue;
/* RTT measurement */
u32 srtt; /* smoothed round trip time << 3 */
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 633fde27f24bc4381ffc4243075f63fcd78cc14a..b4ccb8a6c9c1ff27157aa67597527a6affe11ba0 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -612,6 +612,8 @@ static inline u32 tcp_receive_window(const struct tcp_sock *tp)
*/
extern u32 __tcp_select_window(struct sock *sk);
+void tcp_send_window_probe(struct sock *sk);
+
/* TCP timestamps are only 32-bits, this causes a slight
* complication on 64-bit systems since we store a snapshot
* of jiffies in the buffer control blocks below. We decided
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index bb4200f561589f6ad38dcf8ccabef090c4af5e4c..e38d6f2403211140fe139fd980ec3eacce5a21b6 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1935,7 +1935,9 @@ void tcp_close(struct sock *sk, long timeout)
* advertise a zero window, then kill -9 the FTP client, wheee...
* Note: timeout is always zero in such a case.
*/
- if (data_was_unread) {
+ if (unlikely(tcp_sk(sk)->repair)) {
+ sk->sk_prot->disconnect(sk, 0);
+ } else if (data_was_unread) {
/* Unread data was tossed, zap the connection. */
NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
tcp_set_state(sk, TCP_CLOSE);
@@ -2074,6 +2076,8 @@ int tcp_disconnect(struct sock *sk, int flags)
/* ABORT function of RFC793 */
if (old_state == TCP_LISTEN) {
inet_csk_listen_stop(sk);
+ } else if (unlikely(tp->repair)) {
+ sk->sk_err = ECONNABORTED;
} else if (tcp_need_reset(old_state) ||
(tp->snd_nxt != tp->write_seq &&
(1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
@@ -2125,6 +2129,12 @@ int tcp_disconnect(struct sock *sk, int flags)
}
EXPORT_SYMBOL(tcp_disconnect);
+static inline int tcp_can_repair_sock(struct sock *sk)
+{
+ return capable(CAP_NET_ADMIN) &&
+ ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
+}
+
/*
* Socket option code for TCP.
*/
@@ -2297,6 +2307,42 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
tp->thin_dupack = val;
break;
+ case TCP_REPAIR:
+ if (!tcp_can_repair_sock(sk))
+ err = -EPERM;
+ else if (val == 1) {
+ tp->repair = 1;
+ sk->sk_reuse = SK_FORCE_REUSE;
+ tp->repair_queue = TCP_NO_QUEUE;
+ } else if (val == 0) {
+ tp->repair = 0;
+ sk->sk_reuse = SK_NO_REUSE;
+ tcp_send_window_probe(sk);
+ } else
+ err = -EINVAL;
+
+ break;
+
+ case TCP_REPAIR_QUEUE:
+ if (!tp->repair)
+ err = -EPERM;
+ else if (val < TCP_QUEUES_NR)
+ tp->repair_queue = val;
+ else
+ err = -EINVAL;
+ break;
+
+ case TCP_QUEUE_SEQ:
+ if (sk->sk_state != TCP_CLOSE)
+ err = -EPERM;
+ else if (tp->repair_queue == TCP_SEND_QUEUE)
+ tp->write_seq = val;
+ else if (tp->repair_queue == TCP_RECV_QUEUE)
+ tp->rcv_nxt = val;
+ else
+ err = -EINVAL;
+ break;
+
case TCP_CORK:
/* When set indicates to always queue non-full frames.
* Later the user clears this option and we transmit
@@ -2632,6 +2678,26 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
val = tp->thin_dupack;
break;
+ case TCP_REPAIR:
+ val = tp->repair;
+ break;
+
+ case TCP_REPAIR_QUEUE:
+ if (tp->repair)
+ val = tp->repair_queue;
+ else
+ return -EINVAL;
+ break;
+
+ case TCP_QUEUE_SEQ:
+ if (tp->repair_queue == TCP_SEND_QUEUE)
+ val = tp->write_seq;
+ else if (tp->repair_queue == TCP_RECV_QUEUE)
+ val = tp->rcv_nxt;
+ else
+ return -EINVAL;
+ break;
+
case TCP_USER_TIMEOUT:
val = jiffies_to_msecs(icsk->icsk_user_timeout);
break;
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 0cb86ceb652ff66432ba584fedef8231d94decc6..ba6dad81908eea1b5d7a7e6ddce648cd3c907d2c 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -138,6 +138,14 @@ int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
}
EXPORT_SYMBOL_GPL(tcp_twsk_unique);
+static int tcp_repair_connect(struct sock *sk)
+{
+ tcp_connect_init(sk);
+ tcp_finish_connect(sk, NULL);
+
+ return 0;
+}
+
/* This will initiate an outgoing connection. */
int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
@@ -196,7 +204,8 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
/* Reset inherited state */
tp->rx_opt.ts_recent = 0;
tp->rx_opt.ts_recent_stamp = 0;
- tp->write_seq = 0;
+ if (likely(!tp->repair))
+ tp->write_seq = 0;
}
if (tcp_death_row.sysctl_tw_recycle &&
@@ -247,7 +256,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
sk->sk_gso_type = SKB_GSO_TCPV4;
sk_setup_caps(sk, &rt->dst);
- if (!tp->write_seq)
+ if (!tp->write_seq && likely(!tp->repair))
tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
inet->inet_daddr,
inet->inet_sport,
@@ -255,7 +264,11 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
inet->inet_id = tp->write_seq ^ jiffies;
- err = tcp_connect(sk);
+ if (likely(!tp->repair))
+ err = tcp_connect(sk);
+ else
+ err = tcp_repair_connect(sk);
+
rt = NULL;
if (err)
goto failure;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index db126a6954a2a1b3175128652468957b0d220152..fa442a61be6a872a36a23b05d88e754317d4a07d 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2617,9 +2617,11 @@ void tcp_connect_init(struct sock *sk)
tp->snd_sml = tp->write_seq;
tp->snd_up = tp->write_seq;
tp->snd_nxt = tp->write_seq;
- tp->rcv_nxt = 0;
- tp->rcv_wup = 0;
- tp->copied_seq = 0;
+
+ if (likely(!tp->repair))
+ tp->rcv_nxt = 0;
+ tp->rcv_wup = tp->rcv_nxt;
+ tp->copied_seq = tp->rcv_nxt;
inet_csk(sk)->icsk_rto = TCP_TIMEOUT_INIT;
inet_csk(sk)->icsk_retransmits = 0;
@@ -2790,6 +2792,14 @@ static int tcp_xmit_probe_skb(struct sock *sk, int urgent)
return tcp_transmit_skb(sk, skb, 0, GFP_ATOMIC);
}
+void tcp_send_window_probe(struct sock *sk)
+{
+ if (sk->sk_state == TCP_ESTABLISHED) {
+ tcp_sk(sk)->snd_wl1 = tcp_sk(sk)->rcv_nxt - 1;
+ tcp_xmit_probe_skb(sk, 0);
+ }
+}
+
/* Initiate keepalive or window probe from timer. */
int tcp_write_wakeup(struct sock *sk)
{