+if (timeout > 0) ALARM(timeout);
+
+#ifdef EXIM_SUPPORT_TFO
+/* 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. Other (than SMTP) cases of TCP connections can
+possibly use the data-on-syn, so support that too. */
+
+if (fastopen_blob && f.tcp_fastopen_ok)
+ {
+# ifdef MSG_FASTOPEN
+ /* This is a Linux implementation. */
+
+ if ((rc = sendto(sock, fastopen_blob->data, fastopen_blob->len,
+ MSG_FASTOPEN | MSG_DONTWAIT, s_ptr, s_len)) >= 0)
+ /* seen for with-data, experimental TFO option, with-cookie case */
+ /* seen for with-data, proper TFO opt, with-cookie case */
+ {
+ DEBUG(D_transport|D_v)
+ debug_printf(" TFO mode connection attempt to %s, %lu data\n",
+ address, (unsigned long)fastopen_blob->len);
+ /*XXX also seen on successful TFO, sigh */
+ tcp_out_fastopen = fastopen_blob->len > 0 ? TFO_ATTEMPTED_DATA : TFO_ATTEMPTED_NODATA;
+ }
+ else switch (errno)
+ {
+ case EINPROGRESS: /* expected if we had no cookie for peer */
+ /* seen for no-data, proper TFO option, both cookie-request and with-cookie cases */
+ /* apparently no visibility of the diffference at this point */
+ /* seen for with-data, proper TFO opt, cookie-req */
+ /* with netwk delay, post-conn tcp_info sees unacked 1 for R, 2 for C; code in smtp_out.c */
+ /* ? older Experimental TFO option behaviour ? */
+ DEBUG(D_transport|D_v) debug_printf(" TFO mode sendto, %s data: EINPROGRESS\n",
+ fastopen_blob->len > 0 ? "with" : "no");
+ if (!fastopen_blob->data)
+ {
+ tcp_out_fastopen = TFO_ATTEMPTED_NODATA; /* we tried; unknown if useful yet */
+ rc = 0;
+ }
+ else /* queue unsent data */
+ rc = send(sock, fastopen_blob->data, fastopen_blob->len, 0);
+ break;
+
+ case EOPNOTSUPP:
+ DEBUG(D_transport)
+ debug_printf("Tried TCP Fast Open but apparently not enabled by sysctl\n");
+ goto legacy_connect;
+
+ case EPIPE:
+ DEBUG(D_transport)
+ debug_printf("Tried TCP Fast Open but kernel too old to support it\n");
+ goto legacy_connect;
+ }
+
+# elif defined(EXIM_TFO_FREEBSD)
+ /* Re: https://people.freebsd.org/~pkelsey/tfo-tools/tfo-client.c */
+
+ if (setsockopt(sock, IPPROTO_TCP, TCP_FASTOPEN, &on, sizeof(on)) < 0)
+ {
+ DEBUG(D_transport)
+ debug_printf("Tried TCP Fast Open but apparently not enabled by sysctl\n");
+ goto legacy_connect;
+ }
+ if ((rc = sendto(sock, fastopen_blob->data, fastopen_blob->len, 0,
+ s_ptr, s_len)) >= 0)
+ {
+ DEBUG(D_transport|D_v)
+ debug_printf(" TFO mode connection attempt to %s, %lu data\n",
+ address, (unsigned long)fastopen_blob->len);
+ tcp_out_fastopen = fastopen_blob->len > 0 ? TFO_ATTEMPTED_DATA : TFO_ATTEMPTED_NODATA;
+ }
+
+# elif defined(EXIM_TFO_CONNECTX)
+ /* MacOS */
+ sa_endpoints_t ends = {
+ .sae_srcif = 0, .sae_srcaddr = NULL, .sae_srcaddrlen = 0,
+ .sae_dstaddr = s_ptr, .sae_dstaddrlen = s_len };
+ struct iovec iov = {
+ .iov_base = fastopen_blob->data, .iov_len = fastopen_blob->len };
+ size_t len;
+
+ if ((rc = connectx(sock, &ends, SAE_ASSOCID_ANY,
+ CONNECT_DATA_IDEMPOTENT, &iov, 1, &len, NULL)) == 0)
+ {
+ DEBUG(D_transport|D_v)
+ debug_printf(" TFO mode connection attempt to %s, %lu data\n",
+ address, (unsigned long)fastopen_blob->len);
+ tcp_out_fastopen = fastopen_blob->len > 0 ? TFO_ATTEMPTED_DATA : TFO_ATTEMPTED_NODATA;
+
+ if (len != fastopen_blob->len)
+ DEBUG(D_transport|D_v)
+ debug_printf(" only queued %lu data!\n", (unsigned long)len);
+ }
+ else if (errno == EINPROGRESS)
+ {
+ DEBUG(D_transport|D_v) debug_printf(" TFO mode connectx, %s data: EINPROGRESS\n",
+ fastopen_blob->len > 0 ? "with" : "no");
+ if (!fastopen_blob->data)
+ {
+ tcp_out_fastopen = TFO_ATTEMPTED_NODATA; /* we tried; unknown if useful yet */
+ rc = 0;
+ }
+ else /* assume that no data was queued; block in send */
+ rc = send(sock, fastopen_blob->data, fastopen_blob->len, 0);
+ }
+# endif
+ }
+else
+#endif /*EXIM_SUPPORT_TFO*/
+ {
+#if defined(EXIM_SUPPORT_TFO) && !defined(EXIM_TFO_CONNECTX)
+legacy_connect:
+#endif
+
+ DEBUG(D_transport|D_v) if (fastopen_blob)
+ debug_printf(" non-TFO mode connection attempt to %s, %lu data\n",
+ address, (unsigned long)fastopen_blob->len);
+ if ((rc = connect(sock, s_ptr, s_len)) >= 0)
+ if ( fastopen_blob && fastopen_blob->data && fastopen_blob->len
+ && send(sock, fastopen_blob->data, fastopen_blob->len, 0) < 0)
+ rc = -1;
+ }
+
git://git.exim.org / exim.git / blobdiff