* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2015 */
+/* Copyright (c) University of Cambridge 1995 - 2017 */
/* See the file NOTICE for conditions of use and distribution. */
/* Functions for doing things with sockets. With the advent of IPv6 this has
got messier, so that it's worth pulling out the code into separate functions
-that other parts of Exim can call, expecially as there are now several
+that other parts of Exim can call, especially as there are now several
different places in the code where sockets are used. */
address the remote address, in text form
port the remote port
timeout a timeout (zero for indefinite timeout)
+ fastopen TRUE iff TCP_FASTOPEN can be used
Returns: 0 on success; -1 on failure, with errno set
*/
int
-ip_connect(int sock, int af, const uschar *address, int port, int timeout)
+ip_connect(int sock, int af, const uschar *address, int port, int timeout,
+ BOOL fastopen)
{
struct sockaddr_in s_in4;
struct sockaddr *s_ptr;
callout_address = string_sprintf("[%s]:%d", address, port);
sigalrm_seen = FALSE;
if (timeout > 0) alarm(timeout);
-rc = connect(sock, s_ptr, s_len);
+
+#if defined(TCP_FASTOPEN) && defined(MSG_FASTOPEN)
+/* TCP Fast Open, if the system has a cookie from a previous call to
+this peer, can send data in the SYN packet. The peer can send data
+before it gets our ACK of its SYN,ACK - the latter is useful for
+the SMTP banner. Is there any usage where the former might be?
+We might extend the ip_connect() args for data if so. For now,
+connect in FASTOPEN mode but with zero data.
+*/
+
+if (fastopen)
+ {
+ if ((rc = sendto(sock, NULL, 0, MSG_FASTOPEN | MSG_DONTWAIT, s_ptr, s_len)) < 0)
+ if (errno == EINPROGRESS) /* the expected case */
+ rc = 0;
+ else if(errno == EOPNOTSUPP)
+ {
+ DEBUG(D_transport)
+ debug_printf("Tried TCP Fast Open but apparently not enabled by sysctl\n");
+ rc = connect(sock, s_ptr, s_len);
+ }
+ }
+else
+#endif
+ rc = connect(sock, s_ptr, s_len);
+
save_errno = errno;
alarm(0);
host_item shost;
host_item *h;
int af = 0, fd, fd4 = -1, fd6 = -1;
+BOOL fastopen = tcp_fastopen_ok && type == SOCK_STREAM;
shost.next = NULL;
shost.address = NULL;
/* Try to connect to the server - test each IP till one works */
-for (h = &shost; h != NULL; h = h->next)
+for (h = &shost; h; h = h->next)
{
fd = Ustrchr(h->address, ':') != 0
? fd6 < 0 ? (fd6 = ip_socket(type, af = AF_INET6)) : fd6
}
for(port = portlo; port <= porthi; port++)
- if (ip_connect(fd, af, h->address, port, timeout) == 0)
+ if (ip_connect(fd, af, h->address, port, timeout, fastopen) == 0)
{
if (fd != fd6) close(fd6);
if (fd != fd4) close(fd4);
{
int fodder = 1;
if (setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
- (uschar *)(&fodder), sizeof(fodder)) != 0)
+ US (&fodder), sizeof(fodder)) != 0)
log_write(0, LOG_MAIN, "setsockopt(SO_KEEPALIVE) on connection %s %s "
"failed: %s", torf? "to":"from", address, strerror(errno));
}
do
{
- struct timeval tv = { time_left, 0 };
+ struct timeval tv = { .tv_sec = time_left, .tv_usec = 0 };
FD_ZERO (&select_inset);
FD_SET (fd, &select_inset);