+Argument: signal number (SIGALRM)
+Returns: nothing
+*/
+
+static void
+command_timeout_handler(int sig)
+{
+sig = sig; /* Keep picky compilers happy */
+log_write(L_lost_incoming_connection,
+ LOG_MAIN, "SMTP command timeout on%s connection from %s",
+ (tls_in.active >= 0)? " TLS" : "",
+ host_and_ident(FALSE));
+if (smtp_batched_input)
+ moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
+smtp_notquit_exit(US"command-timeout", US"421",
+ US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
+exim_exit(EXIT_FAILURE);
+}
+
+
+
+/*************************************************
+* SIGTERM received *
+*************************************************/
+
+/* Signal handler for handling SIGTERM. Again, try to finish tidily.
+
+Argument: signal number (SIGTERM)
+Returns: nothing
+*/
+
+static void
+command_sigterm_handler(int sig)
+{
+sig = sig; /* Keep picky compilers happy */
+log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
+if (smtp_batched_input)
+ moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
+smtp_notquit_exit(US"signal-exit", US"421",
+ US"%s: Service not available - closing connection", smtp_active_hostname);
+exim_exit(EXIT_FAILURE);
+}
+
+
+
+
+#ifdef SUPPORT_PROXY
+/*************************************************
+* Restore socket timeout to previous value *
+*************************************************/
+/* If the previous value was successfully retrieved, restore
+it before returning control to the non-proxy routines
+
+Arguments: fd - File descriptor for input
+ get_ok - Successfully retrieved previous values
+ tvtmp - Time struct with previous values
+ vslen - Length of time struct
+Returns: none
+*/
+static void
+restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
+{
+if (get_ok == 0)
+ (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
+}
+
+/*************************************************
+* Check if host is required proxy host *
+*************************************************/
+/* The function determines if inbound host will be a regular smtp host
+or if it is configured that it must use Proxy Protocol. A local
+connection cannot.
+
+Arguments: none
+Returns: bool
+*/
+
+static BOOL
+check_proxy_protocol_host()
+{
+int rc;
+
+if ( sender_host_address
+ && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
+ sender_host_address, NULL)) == OK)
+ {
+ DEBUG(D_receive)
+ debug_printf("Detected proxy protocol configured host\n");
+ proxy_session = TRUE;
+ }
+return proxy_session;
+}
+
+
+/*************************************************
+* Read data until newline or end of buffer *
+*************************************************/
+/* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
+read an entire buffer and assume there will be nothing past a proxy protocol
+header. Our approach normally is to use stdio, but again that relies upon
+"STARTTLS\r\n" and a server response before the client starts TLS handshake, or
+reading _nothing_ before client TLS handshake. So we don't want to use the
+usual buffering reads which may read enough to block TLS starting.
+
+So unfortunately we're down to "read one byte at a time, with a syscall each,
+and expect a little overhead", for all proxy-opened connections which are v1,
+just to handle the TLS-on-connect case. Since SSL functions wrap the
+underlying fd, we can't assume that we can feed them any already-read content.
+
+We need to know where to read to, the max capacity, and we'll read until we
+get a CR and one more character. Let the caller scream if it's CR+!LF.
+
+Return the amount read.
+*/
+
+static int
+swallow_until_crlf(int fd, uschar *base, int already, int capacity)
+{
+uschar *to = base + already;
+uschar *cr;
+int have = 0;
+int ret;
+int last = 0;
+
+/* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
+up through the \r; for the _normal_ case, we haven't yet seen the \r. */
+
+cr = memchr(base, '\r', already);
+if (cr != NULL)
+ {
+ if ((cr - base) < already - 1)
+ {
+ /* \r and presumed \n already within what we have; probably not
+ actually proxy protocol, but abort cleanly. */
+ return 0;
+ }
+ /* \r is last character read, just need one more. */
+ last = 1;
+ }
+
+while (capacity > 0)
+ {
+ do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
+ if (ret == -1)
+ return -1;
+ have++;
+ if (last)
+ return have;
+ if (*to == '\r')
+ last = 1;
+ capacity--;
+ to++;
+ }
+
+/* reached end without having room for a final newline, abort */
+errno = EOVERFLOW;
+return -1;
+}
+
+/*************************************************
+* Setup host for proxy protocol *
+*************************************************/
+/* The function configures the connection based on a header from the
+inbound host to use Proxy Protocol. The specification is very exact
+so exit with an error if do not find the exact required pieces. This
+includes an incorrect number of spaces separating args.
+
+Arguments: none
+Returns: Boolean success
+*/
+
+static void
+setup_proxy_protocol_host()
+{
+union {
+ struct {
+ uschar line[108];
+ } v1;
+ struct {
+ uschar sig[12];
+ uint8_t ver_cmd;
+ uint8_t fam;
+ uint16_t len;
+ union {
+ struct { /* TCP/UDP over IPv4, len = 12 */
+ uint32_t src_addr;
+ uint32_t dst_addr;
+ uint16_t src_port;
+ uint16_t dst_port;
+ } ip4;
+ struct { /* TCP/UDP over IPv6, len = 36 */
+ uint8_t src_addr[16];
+ uint8_t dst_addr[16];
+ uint16_t src_port;
+ uint16_t dst_port;
+ } ip6;
+ struct { /* AF_UNIX sockets, len = 216 */
+ uschar src_addr[108];
+ uschar dst_addr[108];
+ } unx;
+ } addr;
+ } v2;
+} hdr;
+
+/* Temp variables used in PPv2 address:port parsing */
+uint16_t tmpport;
+char tmpip[INET_ADDRSTRLEN];
+struct sockaddr_in tmpaddr;
+char tmpip6[INET6_ADDRSTRLEN];
+struct sockaddr_in6 tmpaddr6;
+
+/* We can't read "all data until end" because while SMTP is
+server-speaks-first, the TLS handshake is client-speaks-first, so for
+TLS-on-connect ports the proxy protocol header will usually be immediately
+followed by a TLS handshake, and with N TLS libraries, we can't reliably
+reinject data for reading by those. So instead we first read "enough to be
+safely read within the header, and figure out how much more to read".
+For v1 we will later read to the end-of-line, for v2 we will read based upon
+the stated length.
+
+The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
+data is needed total. For v1, where the line looks like:
+PROXY TCPn L3src L3dest SrcPort DestPort \r\n
+
+However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
+We seem to support that. So, if we read 14 octets then we can tell if we're
+v2 or v1. If we're v1, we can continue reading as normal.
+
+If we're v2, we can't slurp up the entire header. We need the length in the
+15th & 16th octets, then to read everything after that.
+
+So to safely handle v1 and v2, with client-sent-first supported correctly,
+we have to do a minimum of 3 read calls, not 1. Eww.
+*/
+
+#define PROXY_INITIAL_READ 14
+#define PROXY_V2_HEADER_SIZE 16
+#if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
+# error Code bug in sizes of data to read for proxy usage
+#endif
+
+int get_ok = 0;
+int size, ret;
+int fd = fileno(smtp_in);
+const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
+uschar * iptype; /* To display debug info */
+struct timeval tv;
+struct timeval tvtmp;
+socklen_t vslen = sizeof(struct timeval);
+BOOL yield = FALSE;
+
+/* Save current socket timeout values */
+get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
+
+/* Proxy Protocol host must send header within a short time
+(default 3 seconds) or it's considered invalid */
+tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
+tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
+if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
+ goto bad;
+
+do
+ {
+ /* The inbound host was declared to be a Proxy Protocol host, so
+ don't do a PEEK into the data, actually slurp up enough to be
+ "safe". Can't take it all because TLS-on-connect clients follow
+ immediately with TLS handshake. */
+ ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
+ }
+ while (ret == -1 && errno == EINTR);
+
+if (ret == -1)
+ goto proxyfail;
+
+/* For v2, handle reading the length, and then the rest. */
+if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
+ {
+ int retmore;
+ uint8_t ver;
+
+ /* First get the length fields. */
+ do
+ {
+ retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
+ } while (retmore == -1 && errno == EINTR);
+ if (retmore == -1)
+ goto proxyfail;
+ ret += retmore;
+
+ ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
+
+ /* May 2014: haproxy combined the version and command into one byte to
+ allow two full bytes for the length field in order to proxy SSL
+ connections. SSL Proxy is not supported in this version of Exim, but
+ must still separate values here. */
+
+ if (ver != 0x02)
+ {
+ DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
+ goto proxyfail;
+ }
+
+ /* The v2 header will always be 16 bytes per the spec. */
+ size = 16 + ntohs(hdr.v2.len);
+ DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
+ size, (int)sizeof(hdr));
+
+ /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
+ amount that we need. Double-check that the size is not unreasonable, then
+ get the rest. */
+ if (size > sizeof(hdr))
+ {
+ DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
+ goto proxyfail;
+ }
+
+ do
+ {
+ do
+ {
+ retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
+ } while (retmore == -1 && errno == EINTR);
+ if (retmore == -1)
+ goto proxyfail;
+ ret += retmore;
+ DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
+ } while (ret < size);
+
+ } /* end scope for getting rest of data for v2 */