* [PATCH 1/3] tcp: Move code around
2012-03-06 9:54 [RFC][PATCH 0/3] TCP connection repair (v2) Pavel Emelyanov
@ 2012-03-06 9:55 ` Pavel Emelyanov
2012-03-06 9:55 ` [PATCH 2/3] tcp: Initial repair mode Pavel Emelyanov
` (2 subsequent siblings)
3 siblings, 0 replies; 7+ messages in thread
From: Pavel Emelyanov @ 2012-03-06 9:55 UTC (permalink / raw)
To: Linux Netdev List, David Miller, Tejun Heo, Eric Dumazet
This is just the preparation patch, which makes the needed for
TCP repair code ready for use.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
---
include/net/tcp.h | 3 ++
net/ipv4/tcp.c | 2 +-
net/ipv4/tcp_input.c | 81 +++++++++++++++++++++++++++++--------------------
net/ipv4/tcp_output.c | 4 +-
4 files changed, 54 insertions(+), 36 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 8607e6a..a08e886 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -434,6 +434,9 @@ extern struct sk_buff * tcp_make_synack(struct sock *sk, struct dst_entry *dst,
struct request_values *rvp);
extern int tcp_disconnect(struct sock *sk, int flags);
+void tcp_connect_init(struct sock *sk);
+void tcp_finish_connect(struct sock *sk, struct sk_buff *skb);
+void tcp_queue_rcv(struct sock *sk, struct sk_buff *skb, int hdrlen);
/* From syncookies.c */
extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 22ef5f9..0e0b974 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -916,7 +916,7 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
int iovlen, flags, err, copied;
- int mss_now, size_goal;
+ int mss_now = 0, size_goal;
bool sg;
long timeo;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index ee42d42..04db849 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5282,6 +5282,14 @@ discard:
return 0;
}
+void tcp_queue_rcv(struct sock *sk, struct sk_buff *skb, int hdrlen)
+{
+ __skb_pull(skb, hdrlen);
+ __skb_queue_tail(&sk->sk_receive_queue, skb);
+ skb_set_owner_r(skb, sk);
+ tcp_sk(sk)->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
+}
+
/*
* TCP receive function for the ESTABLISHED state.
*
@@ -5447,10 +5455,7 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPHPHITS);
/* Bulk data transfer: receiver */
- __skb_pull(skb, tcp_header_len);
- __skb_queue_tail(&sk->sk_receive_queue, skb);
- skb_set_owner_r(skb, sk);
- tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
+ tcp_queue_rcv(sk, skb, tcp_header_len);
}
tcp_event_data_recv(sk, skb);
@@ -5516,6 +5521,44 @@ discard:
}
EXPORT_SYMBOL(tcp_rcv_established);
+void tcp_finish_connect(struct sock *sk, struct sk_buff *skb)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct inet_connection_sock *icsk = inet_csk(sk);
+
+ tcp_set_state(sk, TCP_ESTABLISHED);
+
+ if (skb != NULL)
+ security_inet_conn_established(sk, skb);
+
+ /* Make sure socket is routed, for correct metrics. */
+ icsk->icsk_af_ops->rebuild_header(sk);
+
+ tcp_init_metrics(sk);
+
+ tcp_init_congestion_control(sk);
+
+ /* Prevent spurious tcp_cwnd_restart() on first data
+ * packet.
+ */
+ tp->lsndtime = tcp_time_stamp;
+
+ tcp_init_buffer_space(sk);
+
+ if (sock_flag(sk, SOCK_KEEPOPEN))
+ inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tp));
+
+ if (!tp->rx_opt.snd_wscale)
+ __tcp_fast_path_on(tp, tp->snd_wnd);
+ else
+ tp->pred_flags = 0;
+
+ if (!sock_flag(sk, SOCK_DEAD)) {
+ sk->sk_state_change(sk);
+ sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
+ }
+}
+
static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
const struct tcphdr *th, unsigned int len)
{
@@ -5648,36 +5691,8 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
}
smp_mb();
- tcp_set_state(sk, TCP_ESTABLISHED);
-
- security_inet_conn_established(sk, skb);
-
- /* Make sure socket is routed, for correct metrics. */
- icsk->icsk_af_ops->rebuild_header(sk);
-
- tcp_init_metrics(sk);
- tcp_init_congestion_control(sk);
-
- /* Prevent spurious tcp_cwnd_restart() on first data
- * packet.
- */
- tp->lsndtime = tcp_time_stamp;
-
- tcp_init_buffer_space(sk);
-
- if (sock_flag(sk, SOCK_KEEPOPEN))
- inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tp));
-
- if (!tp->rx_opt.snd_wscale)
- __tcp_fast_path_on(tp, tp->snd_wnd);
- else
- tp->pred_flags = 0;
-
- if (!sock_flag(sk, SOCK_DEAD)) {
- sk->sk_state_change(sk);
- sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
- }
+ tcp_finish_connect(sk, skb);
if (sk->sk_write_pending ||
icsk->icsk_accept_queue.rskq_defer_accept ||
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 364784a..1db25af 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2561,7 +2561,7 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
EXPORT_SYMBOL(tcp_make_synack);
/* Do all connect socket setups that can be done AF independent. */
-static void tcp_connect_init(struct sock *sk)
+void tcp_connect_init(struct sock *sk)
{
const struct dst_entry *dst = __sk_dst_get(sk);
struct tcp_sock *tp = tcp_sk(sk);
@@ -2616,6 +2616,7 @@ static void tcp_connect_init(struct sock *sk)
tp->snd_una = tp->write_seq;
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;
@@ -2641,7 +2642,6 @@ int tcp_connect(struct sock *sk)
/* Reserve space for headers. */
skb_reserve(buff, MAX_TCP_HEADER);
- tp->snd_nxt = tp->write_seq;
tcp_init_nondata_skb(buff, tp->write_seq++, TCPHDR_SYN);
TCP_ECN_send_syn(sk, buff);
--
1.5.5.6
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH 2/3] tcp: Initial repair mode
2012-03-06 9:54 [RFC][PATCH 0/3] TCP connection repair (v2) Pavel Emelyanov
2012-03-06 9:55 ` [PATCH 1/3] tcp: Move code around Pavel Emelyanov
@ 2012-03-06 9:55 ` Pavel Emelyanov
2012-03-06 13:11 ` Glauber Costa
2012-03-06 9:55 ` [PATCH 3/3] tcp: Repair socket queues Pavel Emelyanov
2012-03-06 21:14 ` [RFC][PATCH 0/3] TCP connection repair (v2) David Miller
3 siblings, 1 reply; 7+ messages in thread
From: Pavel Emelyanov @ 2012-03-06 9:55 UTC (permalink / raw)
To: Linux Netdev List, David Miller, Tejun Heo, Eric Dumazet
This includes (according the the previous description):
* TCP_REPAIR sockoption
This one just puts the socket in/out of the repair mode.
Allowed for CAP_SYS_ADMIN and for closed/establised sockets only.
When repair mode is turned off and the socket happens to be in
the established state the window probe is sent to the peer to
'unlock' the connection.
* TCP_REPAIR_QUEUE sockoption
This one sets the queue which we're about to repair. The
'no-queue' is set by default.
* TCP_QUEUE_SEQ socoption
Sets the write_seq/copied_seq of a selected repaired queue.
Allowed for TCP_CLOSE-d sockets only. When the socket changes
its state the other seq-s are changed by the kernel according
to the protocol rules (most of the existing code is actually
reused).
* Ability to forcibly bind a socket to a port
The sk->sk_reuse is set to 2 denoting, that the socket is question
should be bound as if all the others in the system are configured
with the SO_REUSEADDR option.
* Immediate connect modification
The connect syscall initializes the connection, then directly jumps
to the code which finalizes it.
* Silent close modification
The close just aborts the connection (similar to SO_LINGER with 0
time) but without sending any FIN/RST-s to peer.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
---
include/linux/tcp.h | 14 ++++++++-
include/net/tcp.h | 2 +
net/ipv4/inet_connection_sock.c | 3 ++
net/ipv4/tcp.c | 63 ++++++++++++++++++++++++++++++++++++++-
net/ipv4/tcp_ipv4.c | 19 ++++++++++--
net/ipv4/tcp_output.c | 16 ++++++++--
6 files changed, 109 insertions(+), 8 deletions(-)
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index b6c62d2..4e90e6a 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 a08e886..9f4aa4c 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -611,6 +611,8 @@ 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/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 19d66ce..92788af 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -172,6 +172,9 @@ have_snum:
goto tb_not_found;
tb_found:
if (!hlist_empty(&tb->owners)) {
+ if (sk->sk_reuse == 2)
+ goto success;
+
if (tb->fastreuse > 0 &&
sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
smallest_size == -1) {
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 0e0b974..8d9b2bc 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1932,7 +1932,9 @@ 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 (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);
@@ -2071,6 +2073,8 @@ 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))) {
@@ -2294,6 +2298,43 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
tp->thin_dupack = val;
break;
+ case TCP_REPAIR:
+ if (!capable(CAP_SYS_ADMIN) || !(sk->sk_state == TCP_CLOSE ||
+ sk->sk_state == TCP_ESTABLISHED))
+ err = -EPERM;
+ else if (val == 1) {
+ tp->repair = 1;
+ sk->sk_reuse = 2;
+ tp->repair_queue = TCP_NO_QUEUE;
+ } else if (val == 0) {
+ tp->repair = 0;
+ sk->sk_reuse = 0;
+ 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->copied_seq = 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
@@ -2629,6 +2670,26 @@ 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->copied_seq;
+ 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 94abee8..6118486 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -137,6 +137,14 @@ 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)
{
@@ -195,7 +203,8 @@ 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 (!tp->repair)
+ tp->write_seq = 0;
}
if (tcp_death_row.sysctl_tw_recycle &&
@@ -246,7 +255,7 @@ 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 && !tp->repair)
tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
inet->inet_daddr,
inet->inet_sport,
@@ -254,7 +263,11 @@ 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 1db25af..f0525d1 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 (!tp->repair)
+ tp->copied_seq = 0;
+ tp->rcv_wup = tp->copied_seq;
+ tp->rcv_nxt = tp->copied_seq;
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)
{
--
1.5.5.6
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH 2/3] tcp: Initial repair mode
2012-03-06 9:55 ` [PATCH 2/3] tcp: Initial repair mode Pavel Emelyanov
@ 2012-03-06 13:11 ` Glauber Costa
2012-03-06 20:16 ` David Miller
0 siblings, 1 reply; 7+ messages in thread
From: Glauber Costa @ 2012-03-06 13:11 UTC (permalink / raw)
To: Pavel Emelyanov; +Cc: Linux Netdev List, David Miller, Tejun Heo, Eric Dumazet
On 03/06/2012 01:55 PM, Pavel Emelyanov wrote:
> This includes (according the the previous description):
>
> * TCP_REPAIR sockoption
>
> This one just puts the socket in/out of the repair mode.
> Allowed for CAP_SYS_ADMIN and for closed/establised sockets only.
> When repair mode is turned off and the socket happens to be in
> the established state the window probe is sent to the peer to
> 'unlock' the connection.
Why not CAP_NET_ADMIN, or something similar?
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 2/3] tcp: Initial repair mode
2012-03-06 13:11 ` Glauber Costa
@ 2012-03-06 20:16 ` David Miller
0 siblings, 0 replies; 7+ messages in thread
From: David Miller @ 2012-03-06 20:16 UTC (permalink / raw)
To: glommer; +Cc: xemul, netdev, tj, eric.dumazet
From: Glauber Costa <glommer@parallels.com>
Date: Tue, 6 Mar 2012 17:11:47 +0400
> On 03/06/2012 01:55 PM, Pavel Emelyanov wrote:
>> This includes (according the the previous description):
>>
>> * TCP_REPAIR sockoption
>>
>> This one just puts the socket in/out of the repair mode.
>> Allowed for CAP_SYS_ADMIN and for closed/establised sockets only.
>> When repair mode is turned off and the socket happens to be in
>> the established state the window probe is sent to the peer to
>> 'unlock' the connection.
>
> Why not CAP_NET_ADMIN, or something similar?
Agreed, we made this kind of mistake with the transparent proxy stuff,
let's not do that again.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH 3/3] tcp: Repair socket queues
2012-03-06 9:54 [RFC][PATCH 0/3] TCP connection repair (v2) Pavel Emelyanov
2012-03-06 9:55 ` [PATCH 1/3] tcp: Move code around Pavel Emelyanov
2012-03-06 9:55 ` [PATCH 2/3] tcp: Initial repair mode Pavel Emelyanov
@ 2012-03-06 9:55 ` Pavel Emelyanov
2012-03-06 21:14 ` [RFC][PATCH 0/3] TCP connection repair (v2) David Miller
3 siblings, 0 replies; 7+ messages in thread
From: Pavel Emelyanov @ 2012-03-06 9:55 UTC (permalink / raw)
To: Linux Netdev List, David Miller, Tejun Heo, Eric Dumazet
Reading queues under repair mode is done with recvmsg call.
The queue-under-repair set by TCP_REPAIR_QUEUE option is used
to determine which queue should be read. Thus both send and
receive queue can be read with this.
Caller must pass the MSG_PEEK flag.
Writing to queues is done with sendmsg call and yet again --
the repair-queue option can be used to push data into the
receive queue.
When putting an skb into receive queue a zero tcp header is
appented to its head to address the tcp_hdr(skb)->syn and
the ->fin checks by the (after repair) tcp_recvmsg. (This is
not fully correct, yes, need more work with the ->fin one).
When the repair mode is turned off, the write queue seqs are
updated so that the whole queue is considered to be 'already sent,
waiting for ACKs' (write_seq = snd_nxt <= snd_una). From the
protocol POV the send queue looks like it was sent, but the data
between the write_seq and snd_nxt is lost in the network.
This helps to avoid another sockoption for setting the snd_nxt
sequence. Leaving the whole queue in a 'not yet sent' state (as
it will be after sendmsg-s) will not allow to receive any acks
from the peer since the ack_seq will be after the snd_nxt. Thus
even the ack for the window probe will be dropped and the
connection will be 'locked' with the zero peer window.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
---
net/ipv4/tcp.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++--
net/ipv4/tcp_output.c | 1 +
2 files changed, 88 insertions(+), 3 deletions(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 8d9b2bc..eba6696 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -909,6 +909,39 @@ static inline int select_size(const struct sock *sk, bool sg)
return tmp;
}
+static int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size)
+{
+ struct sk_buff *skb;
+ struct tcp_skb_cb *cb;
+ struct tcphdr *th;
+
+ skb = alloc_skb(size + sizeof(*th), sk->sk_allocation);
+ if (!skb)
+ goto err;
+
+ th = (struct tcphdr *)skb_put(skb, sizeof(*th));
+ skb_reset_transport_header(skb);
+ memset(th, 0, sizeof(*th));
+
+ if (memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size))
+ goto err_free;
+
+ cb = TCP_SKB_CB(skb);
+
+ TCP_SKB_CB(skb)->seq = tcp_sk(sk)->rcv_nxt;
+ TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq + size;
+ TCP_SKB_CB(skb)->ack_seq = tcp_sk(sk)->snd_una - 1;
+
+ tcp_queue_rcv(sk, skb, sizeof(*th));
+
+ return size;
+
+err_free:
+ kfree_skb(skb);
+err:
+ return -ENOMEM;
+}
+
int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
size_t size)
{
@@ -930,6 +964,19 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
goto out_err;
+ if (unlikely(tp->repair)) {
+ if (tp->repair_queue == TCP_RECV_QUEUE) {
+ copied = tcp_send_rcvq(sk, msg, size);
+ goto out;
+ }
+
+ err = -EINVAL;
+ if (tp->repair_queue == TCP_NO_QUEUE)
+ goto out_err;
+
+ /* 'common' sending to sendq */
+ }
+
/* This should be in poll */
clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
@@ -1087,7 +1134,7 @@ new_segment:
if ((seglen -= copy) == 0 && iovlen == 0)
goto out;
- if (skb->len < max || (flags & MSG_OOB))
+ if (skb->len < max || (flags & MSG_OOB) || tp->repair)
continue;
if (forced_push(tp)) {
@@ -1100,7 +1147,7 @@ new_segment:
wait_for_sndbuf:
set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
- if (copied)
+ if (copied && !tp->repair)
tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
@@ -1111,7 +1158,7 @@ wait_for_memory:
}
out:
- if (copied)
+ if (copied && !tp->repair)
tcp_push(sk, flags, mss_now, tp->nonagle);
release_sock(sk);
return copied;
@@ -1185,6 +1232,24 @@ static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
return -EAGAIN;
}
+static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
+{
+ struct sk_buff *skb;
+ int copied = 0, err = 0;
+
+ /* XXX -- need to support SO_PEEK_OFF */
+
+ skb_queue_walk(&sk->sk_write_queue, skb) {
+ err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, skb->len);
+ if (err)
+ break;
+
+ copied += skb->len;
+ }
+
+ return err ?: copied;
+}
+
/* Clean up the receive buffer for full frames taken by the user,
* then send an ACK if necessary. COPIED is the number of bytes
* tcp_recvmsg has given to the user so far, it speeds up the
@@ -1430,6 +1495,21 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
if (flags & MSG_OOB)
goto recv_urg;
+ if (unlikely(tp->repair)) {
+ err = -EPERM;
+ if (!(flags & MSG_PEEK))
+ goto out;
+
+ if (tp->repair_queue == TCP_SEND_QUEUE)
+ goto recv_sndq;
+
+ err = -EINVAL;
+ if (tp->repair_queue == TCP_NO_QUEUE)
+ goto out;
+
+ /* 'common' recv queue MSG_PEEK-ing */
+ }
+
seq = &tp->copied_seq;
if (flags & MSG_PEEK) {
peek_seq = tp->copied_seq;
@@ -1780,6 +1860,10 @@ out:
recv_urg:
err = tcp_recv_urg(sk, msg, len, flags);
goto out;
+
+recv_sndq:
+ err = tcp_peek_sndq(sk, msg, len);
+ goto out;
}
EXPORT_SYMBOL(tcp_recvmsg);
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index f0525d1..5e58c1a 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2796,6 +2796,7 @@ 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_sk(sk)->snd_nxt = tcp_sk(sk)->write_seq;
tcp_xmit_probe_skb(sk, 0);
}
}
--
1.5.5.6
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [RFC][PATCH 0/3] TCP connection repair (v2)
2012-03-06 9:54 [RFC][PATCH 0/3] TCP connection repair (v2) Pavel Emelyanov
` (2 preceding siblings ...)
2012-03-06 9:55 ` [PATCH 3/3] tcp: Repair socket queues Pavel Emelyanov
@ 2012-03-06 21:14 ` David Miller
3 siblings, 0 replies; 7+ messages in thread
From: David Miller @ 2012-03-06 21:14 UTC (permalink / raw)
To: xemul; +Cc: netdev, tj, eric.dumazet
From: Pavel Emelyanov <xemul@parallels.com>
Date: Tue, 06 Mar 2012 13:54:38 +0400
> Attempt #2 with transparent TCP connection hijacking.
This looks a lot better, the TCP_CLOSE state check makes it more clear
how this is going to be used.
Please fix up the indentation in patch #2.
+ if (!capable(CAP_SYS_ADMIN) || !(sk->sk_state == TCP_CLOSE ||
+ sk->sk_state == TCP_ESTABLISHED))
And once you sort out the details of the ->{syn,fin} bit in the fake headers
added to the repair queues you can resubmit this.
Thanks.
^ permalink raw reply [flat|nested] 7+ messages in thread