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authorRory Byrne <[email protected]>2015-05-02 20:34:24 +0100
committerRory Byrne <[email protected]>2015-06-09 20:50:14 +0100
commit0098eed847516cc6760d961421c83527816e35ae (patch)
tree0ca38a952161ce5a108d45e9e71c45a9bf37a8bd /erts/emulator
parent4f63e427f1345b40b484ef16f6ff5e922bf14dac (diff)
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Apply 'show_econnreset' socket option to send errors as well
Up till now all send errors have been translated into a generic {error, closed}. This patch allows {error, econnreset} to be returned on send errors when it is detected that the TCP peer has sent an RST.
Diffstat (limited to 'erts/emulator')
-rw-r--r--erts/emulator/drivers/common/inet_drv.c84
1 files changed, 76 insertions, 8 deletions
diff --git a/erts/emulator/drivers/common/inet_drv.c b/erts/emulator/drivers/common/inet_drv.c
index b5903f0c07..a8c58a8149 100644
--- a/erts/emulator/drivers/common/inet_drv.c
+++ b/erts/emulator/drivers/common/inet_drv.c
@@ -836,6 +836,8 @@ static int my_strncasecmp(const char *s1, const char *s2, size_t n)
#define TCP_ADDF_PENDING_SHUTDOWN \
(TCP_ADDF_PENDING_SHUT_WR | TCP_ADDF_PENDING_SHUT_RDWR)
#define TCP_ADDF_SHOW_ECONNRESET 64 /* Tell user about incoming RST */
+#define TCP_ADDF_DELAYED_ECONNRESET 128 /* An ECONNRESET error occured on send or shutdown */
+#define TCP_ADDF_SHUTDOWN_WR_DONE 256 /* A shutdown(sock, SHUT_WR) or SHUT_RDWR was made */
/* *_REQ_* replies */
#define INET_REP_ERROR 0
@@ -6140,7 +6142,12 @@ static int inet_set_opts(inet_descriptor* desc, char* ptr, int len)
desc->active_count = 0;
if ((desc->stype == SOCK_STREAM) && (desc->active != INET_PASSIVE) &&
(desc->state == INET_STATE_CLOSED)) {
- tcp_closed_message((tcp_descriptor *) desc);
+ tcp_descriptor *tdesc = (tcp_descriptor *) desc;
+ if (tdesc->tcp_add_flags & TCP_ADDF_DELAYED_ECONNRESET) {
+ tdesc->tcp_add_flags &= ~TCP_ADDF_DELAYED_ECONNRESET;
+ tcp_error_message(tdesc, ECONNRESET);
+ }
+ tcp_closed_message(tdesc);
if (desc->exitf) {
driver_exit(desc->port, 0);
return 0; /* Give up on this socket, descriptor lost */
@@ -9466,7 +9473,11 @@ static ErlDrvSSizeT tcp_inet_ctl(ErlDrvData e, unsigned int cmd,
if (desc->tcp_add_flags & TCP_ADDF_DELAYED_CLOSE_RECV) {
desc->tcp_add_flags &= ~(TCP_ADDF_DELAYED_CLOSE_RECV|
TCP_ADDF_DELAYED_CLOSE_SEND);
- return ctl_reply(INET_REP_ERROR, "closed", 6, rbuf, rsize);
+ if (desc->tcp_add_flags & TCP_ADDF_DELAYED_ECONNRESET) {
+ desc->tcp_add_flags &= ~TCP_ADDF_DELAYED_ECONNRESET;
+ return ctl_reply(INET_REP_ERROR, "econnreset", 10, rbuf, rsize);
+ } else
+ return ctl_reply(INET_REP_ERROR, "closed", 6, rbuf, rsize);
}
return ctl_error(ENOTCONN, rbuf, rsize);
}
@@ -9527,6 +9538,8 @@ static ErlDrvSSizeT tcp_inet_ctl(ErlDrvData e, unsigned int cmd,
return ctl_reply(INET_REP_OK, NULL, 0, rbuf, rsize);
}
if (IS_SOCKET_ERROR(sock_shutdown(INETP(desc)->s, how))) {
+ if (how != TCP_SHUT_RD)
+ desc->tcp_add_flags |= TCP_ADDF_SHUTDOWN_WR_DONE;
return ctl_error(sock_errno(), rbuf, rsize);
} else {
return ctl_reply(INET_REP_OK, NULL, 0, rbuf, rsize);
@@ -9661,7 +9674,13 @@ static void tcp_inet_commandv(ErlDrvData e, ErlIOVec* ev)
if (!IS_CONNECTED(INETP(desc))) {
if (desc->tcp_add_flags & TCP_ADDF_DELAYED_CLOSE_SEND) {
desc->tcp_add_flags &= ~TCP_ADDF_DELAYED_CLOSE_SEND;
- inet_reply_error_am(INETP(desc), am_closed);
+ if (desc->tcp_add_flags & TCP_ADDF_DELAYED_ECONNRESET) {
+ /* Don't clear flag. Leave it enabled for the next receive
+ * operation.
+ */
+ inet_reply_error(INETP(desc), ECONNRESET);
+ } else
+ inet_reply_error_am(INETP(desc), am_closed);
}
else
inet_reply_error(INETP(desc), ENOTCONN);
@@ -10578,6 +10597,9 @@ static int tcp_inet_input(tcp_descriptor* desc, HANDLE event)
static int tcp_send_or_shutdown_error(tcp_descriptor* desc, int err)
{
+ int show_econnreset = (err == ECONNRESET
+ && desc->tcp_add_flags & TCP_ADDF_SHOW_ECONNRESET);
+
/*
* If the port is busy, we must do some clean-up before proceeding.
*/
@@ -10593,14 +10615,21 @@ static int tcp_send_or_shutdown_error(tcp_descriptor* desc, int err)
/*
* We used to handle "expected errors" differently from unexpected ones.
- * Now we handle all errors in the same way. We just have to distinguish
- * between passive and active sockets.
+ * Now we handle all errors in the same way (unless the show_econnreset
+ * socket option is enabled). We just have to distinguish between passive
+ * and active sockets.
*/
DEBUGF(("driver_failure_eof(%ld) in %s, line %d\r\n",
(long)desc->inet.port, __FILE__, __LINE__));
if (desc->inet.active) {
- tcp_closed_message(desc);
- inet_reply_error_am(INETP(desc), am_closed);
+ if (show_econnreset) {
+ tcp_error_message(desc, err);
+ tcp_closed_message(desc);
+ inet_reply_error(INETP(desc), err);
+ } else {
+ tcp_closed_message(desc);
+ inet_reply_error_am(INETP(desc), am_closed);
+ }
if (desc->inet.exitf)
driver_exit(desc->inet.port, 0);
else
@@ -10612,7 +10641,10 @@ static int tcp_send_or_shutdown_error(tcp_descriptor* desc, int err)
erl_inet_close(INETP(desc));
if (desc->inet.caller) {
- inet_reply_error_am(INETP(desc), am_closed);
+ if (show_econnreset)
+ inet_reply_error(INETP(desc), err);
+ else
+ inet_reply_error_am(INETP(desc), am_closed);
}
else {
/* No blocking send op to reply to right now.
@@ -10629,12 +10661,46 @@ static int tcp_send_or_shutdown_error(tcp_descriptor* desc, int err)
* in the receive operation.
*/
desc->tcp_add_flags |= TCP_ADDF_DELAYED_CLOSE_RECV;
+
+ if (show_econnreset) {
+ /* Return {error, econnreset} instead of {error, closed}
+ * on send or receive operations.
+ */
+ desc->tcp_add_flags |= TCP_ADDF_DELAYED_ECONNRESET;
+ }
}
return -1;
}
static int tcp_send_error(tcp_descriptor* desc, int err)
{
+ /* EPIPE errors usually occur in one of three ways:
+ * 1. We write to a socket when we've already shutdown() the write side. On
+ * Windows the error returned for this is ESHUTDOWN rather than EPIPE.
+ * 2. The TCP peer sends us an RST through no fault of our own (perhaps
+ * by aborting the connection using SO_LINGER) and we then attempt
+ * to write to the socket. On Linux and Windows we would actually
+ * receive an ECONNRESET error for this, but on the BSDs, Darwin,
+ * Illumos and presumably Solaris, it's an EPIPE.
+ * 3. We cause the TCP peer to send us an RST by writing to a socket
+ * after we receive a FIN from them. Our first write will be
+ * successful, but if the they have closed the connection (rather
+ * than just shutting down the write side of it) this will cause their
+ * OS to send us an RST. Then, when we attempt to write to the socket
+ * a second time, we will get an EPIPE error. On Windows we get an
+ * ECONNABORTED.
+ *
+ * What we are going to do here is to treat all EPIPE messages that aren't
+ * of type 1 as ECONNRESET errors. This will allow users who have the
+ * show_econnreset socket option enabled to receive {error, econnreset} on
+ * both send and recv operations to indicate that an RST has been received.
+ */
+#ifdef __WIN_32__
+ if (err == ECONNABORTED)
+ err = ECONNRESET;
+#endif
+ if (err == EPIPE && !(desc->tcp_add_flags & TCP_ADDF_SHUTDOWN_WR_DONE))
+ err = ECONNRESET;
return tcp_send_or_shutdown_error(desc, err);
}
@@ -10854,6 +10920,8 @@ static void tcp_shutdown_async(tcp_descriptor* desc)
TCP_SHUT_WR : TCP_SHUT_RDWR;
if (IS_SOCKET_ERROR(sock_shutdown(INETP(desc)->s, how)))
tcp_shutdown_error(desc, sock_errno());
+ else
+ desc->tcp_add_flags |= TCP_ADDF_SHUTDOWN_WR_DONE;
}
#ifdef __OSE__