From: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
This adds two auxiliary states to deal with passive closes:
* PASSIVE_CLOSE (reached from OPEN via reception of Close) and
* PASSIVE_CLOSEREQ (reached from OPEN via reception of CloseReq)
as internal intermediate states.
These states are used to allow a receiver to process unread data before
acknowledging the received connection-termination-request (the Close/CloseReq).
Without such support, it will happen that passively-closed sockets enter CLOSED
state while there is still unprocessed data in the queue; leading to unexpected
and erratic API behaviour.
PASSIVE_CLOSE has been mapped into TCPF_CLOSE_WAIT, so that the code will
seamlessly work with inet_accept() (which tests for this state).
The state names are thanks to Arnaldo, who suggested this naming scheme
following an earlier revision of this patch.
Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
include/linux/dccp.h | 56 ++++++++++++++++++++++++++++++++++---------------
net/dccp/proto.c | 22 ++++++++++---------
2 files changed, 51 insertions(+), 27 deletions(-)
diff --git a/include/linux/dccp.h b/include/linux/dccp.h
index a007326..8b3f9ad 100644
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -227,29 +227,51 @@ struct dccp_so_feat {
#include <net/tcp_states.h>
enum dccp_state {
- DCCP_OPEN = TCP_ESTABLISHED,
- DCCP_REQUESTING = TCP_SYN_SENT,
- DCCP_LISTEN = TCP_LISTEN,
- DCCP_RESPOND = TCP_SYN_RECV,
- DCCP_CLOSING = TCP_CLOSING,
- DCCP_TIME_WAIT = TCP_TIME_WAIT,
- DCCP_CLOSED = TCP_CLOSE,
- DCCP_PARTOPEN = TCP_MAX_STATES,
+ DCCP_OPEN = TCP_ESTABLISHED,
+ DCCP_REQUESTING = TCP_SYN_SENT,
+ DCCP_LISTEN = TCP_LISTEN,
+ DCCP_RESPOND = TCP_SYN_RECV,
+ /*
+ * States involved in closing a DCCP connection:
+ * 1) ACTIVE_CLOSEREQ is entered by a server sending a CloseReq.
+ *
+ * 2) CLOSING can have three different meanings (RFC 4340, 8.3):
+ * a. Client has performed active-close, has sent a Close to the server
+ * from state OPEN or PARTOPEN, and is waiting for the final Reset
+ * (in this case, SOCK_DONE == 1).
+ * b. Client is asked to perform passive-close, by receiving a CloseReq
+ * in (PART)OPEN state. It sends a Close and waits for final Reset
+ * (in this case, SOCK_DONE == 0).
+ * c. Server performs an active-close as in (a), keeps TIMEWAIT state.
+ *
+ * 3) The following intermediate states are employed to give passively
+ * closing nodes a chance to process their unread data:
+ * - PASSIVE_CLOSE (from OPEN => CLOSED) and
+ * - PASSIVE_CLOSEREQ (from (PART)OPEN to CLOSING; case (b) above).
+ */
+ DCCP_ACTIVE_CLOSEREQ = TCP_FIN_WAIT1,
+ DCCP_PASSIVE_CLOSE = TCP_CLOSE_WAIT, /* any node receiving a Close */
+ DCCP_CLOSING = TCP_CLOSING,
+ DCCP_TIME_WAIT = TCP_TIME_WAIT,
+ DCCP_CLOSED = TCP_CLOSE,
+ DCCP_PARTOPEN = TCP_MAX_STATES,
+ DCCP_PASSIVE_CLOSEREQ, /* clients receiving CloseReq */
DCCP_MAX_STATES
};
-#define DCCP_STATE_MASK 0xf
+#define DCCP_STATE_MASK 0x1f
#define DCCP_ACTION_FIN (1<<7)
enum {
- DCCPF_OPEN = TCPF_ESTABLISHED,
- DCCPF_REQUESTING = TCPF_SYN_SENT,
- DCCPF_LISTEN = TCPF_LISTEN,
- DCCPF_RESPOND = TCPF_SYN_RECV,
- DCCPF_CLOSING = TCPF_CLOSING,
- DCCPF_TIME_WAIT = TCPF_TIME_WAIT,
- DCCPF_CLOSED = TCPF_CLOSE,
- DCCPF_PARTOPEN = 1 << DCCP_PARTOPEN,
+ DCCPF_OPEN = TCPF_ESTABLISHED,
+ DCCPF_REQUESTING = TCPF_SYN_SENT,
+ DCCPF_LISTEN = TCPF_LISTEN,
+ DCCPF_RESPOND = TCPF_SYN_RECV,
+ DCCPF_ACTIVE_CLOSEREQ = TCPF_FIN_WAIT1,
+ DCCPF_CLOSING = TCPF_CLOSING,
+ DCCPF_TIME_WAIT = TCPF_TIME_WAIT,
+ DCCPF_CLOSED = TCPF_CLOSE,
+ DCCPF_PARTOPEN = (1 << DCCP_PARTOPEN),
};
static inline struct dccp_hdr *dccp_hdr(const struct sk_buff *skb)
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 73006b7..3489d3f 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -60,8 +60,7 @@ void dccp_set_state(struct sock *sk, const int state)
{
const int oldstate = sk->sk_state;
- dccp_pr_debug("%s(%p) %-10.10s -> %s\n",
- dccp_role(sk), sk,
+ dccp_pr_debug("%s(%p) %s --> %s\n", dccp_role(sk), sk,
dccp_state_name(oldstate), dccp_state_name(state));
WARN_ON(state == oldstate);
@@ -134,14 +133,17 @@ EXPORT_SYMBOL_GPL(dccp_packet_name);
const char *dccp_state_name(const int state)
{
static char *dccp_state_names[] = {
- [DCCP_OPEN] = "OPEN",
- [DCCP_REQUESTING] = "REQUESTING",
- [DCCP_PARTOPEN] = "PARTOPEN",
- [DCCP_LISTEN] = "LISTEN",
- [DCCP_RESPOND] = "RESPOND",
- [DCCP_CLOSING] = "CLOSING",
- [DCCP_TIME_WAIT] = "TIME_WAIT",
- [DCCP_CLOSED] = "CLOSED",
+ [DCCP_OPEN] = "OPEN",
+ [DCCP_REQUESTING] = "REQUESTING",
+ [DCCP_PARTOPEN] = "PARTOPEN",
+ [DCCP_LISTEN] = "LISTEN",
+ [DCCP_RESPOND] = "RESPOND",
+ [DCCP_CLOSING] = "CLOSING",
+ [DCCP_ACTIVE_CLOSEREQ] = "CLOSEREQ",
+ [DCCP_PASSIVE_CLOSE] = "PASSIVE_CLOSE",
+ [DCCP_PASSIVE_CLOSEREQ] = "PASSIVE_CLOSEREQ",
+ [DCCP_TIME_WAIT] = "TIME_WAIT",
+ [DCCP_CLOSED] = "CLOSED",
};
if (state >= DCCP_MAX_STATES)
--
1.5.3.4
-
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