X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/a39bd74d3e942db1b465cae643e1a4766ffb304e..17ba0f52b8df4e6ece849deac1b9d6b88bdc26c6:/src/src/ip.c

diff --git a/src/src/ip.c b/src/src/ip.c
index 5b37e3898..bf332b160 100644
--- a/src/src/ip.c
+++ b/src/src/ip.c
@@ -2,18 +2,24 @@
 *     Exim - an Internet mail transport agent    *
 *************************************************/
 
-/* Copyright (c) University of Cambridge 1995 - 2014 */
+/* Copyright (c) University of Cambridge 1995 - 2018 */
 /* 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. */
 
 
 #include "exim.h"
 
 
+#if defined(TCP_FASTOPEN)
+# if defined(MSG_FASTOPEN) || defined(EXIM_TFO_CONNECTX) || defined(EXIM_TFO_FREEBSD)
+#  define EXIM_SUPPORT_TFO
+# endif
+#endif
+
 /*************************************************
 *             Create a socket                    *
 *************************************************/
@@ -101,7 +107,7 @@ int
 ip_addr(void * sin_, int af, const uschar * address, int port)
 {
 union sockaddr_46 * sin = sin_;
-memset(sin, 0, sizeof(sin));
+memset(sin, 0, sizeof(*sin));
 
 /* Setup code when using an IPv6 socket. The wildcard address is ":", to
 ensure an IPv6 socket is used. */
@@ -175,12 +181,15 @@ Arguments:
   address     the remote address, in text form
   port        the remote port
   timeout     a timeout (zero for indefinite timeout)
+  fastopen_blob    non-null iff TCP_FASTOPEN can be used; may indicate early-data to
+		be sent in SYN segment.  Any such data must be idempotent.
 
 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,
+  const blob * fastopen_blob)
 {
 struct sockaddr_in s_in4;
 struct sockaddr *s_ptr;
@@ -218,17 +227,134 @@ IPv6 support. */
 /* If no connection timeout is set, just call connect() without setting a
 timer, thereby allowing the inbuilt OS timeout to operate. */
 
+callout_address = string_sprintf("[%s]:%d", address, port);
 sigalrm_seen = FALSE;
-if (timeout > 0) alarm(timeout);
-rc = connect(sock, s_ptr, s_len);
+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 if (errno == 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 ? */
+    {					/* queue unsent data */
+    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
+      rc = send(sock, fastopen_blob->data, fastopen_blob->len, 0);
+    }
+  else if(errno == EOPNOTSUPP)
+    {
+    DEBUG(D_transport)
+      debug_printf("Tried TCP Fast Open but apparently not enabled by sysctl\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;
+  }
+
 save_errno = errno;
-alarm(0);
+ALARM_CLR(0);
 
 /* There is a testing facility for simulating a connection timeout, as I
 can't think of any other way of doing this. It converts a connection refused
 into a timeout if the timeout is set to 999999. */
 
-if (running_in_test_harness  && save_errno == ECONNREFUSED && timeout == 999999)
+if (f.running_in_test_harness  && save_errno == ECONNREFUSED && timeout == 999999)
   {
   rc = -1;
   save_errno = EINTR;
@@ -237,7 +363,8 @@ if (running_in_test_harness  && save_errno == ECONNREFUSED && timeout == 999999)
 
 /* Success */
 
-if (rc >= 0) return 0;
+if (rc >= 0)
+  return 0;
 
 /* A failure whose error code is "Interrupted system call" is in fact
 an externally applied timeout if the signal handler has been run. */
@@ -258,22 +385,23 @@ return -1;
 Arguments:
   type          SOCK_DGRAM or SOCK_STREAM
   af            AF_INET6 or AF_INET for the socket type
-  address       the remote address, in text form
+  hostname	host name, or ip address (as text)
   portlo,porthi the remote port range
   timeout       a timeout
-  connhost	if not NULL, host_item filled in with connection details
+  connhost	if not NULL, host_item to be filled in with connection details
   errstr        pointer for allocated string on error
+  fastopen_blob	with SOCK_STREAM, if non-null, request TCP Fast Open.
+		Additionally, optional idempotent early-data to send
 
 Return:
   socket fd, or -1 on failure (having allocated an error string)
 */
 int
 ip_connectedsocket(int type, const uschar * hostname, int portlo, int porthi,
-	int timeout, host_item * connhost, uschar ** errstr)
+      int timeout, host_item * connhost, uschar ** errstr, const blob * fastopen_blob)
 {
-int namelen, port;
+int namelen;
 host_item shost;
-host_item *h;
 int af = 0, fd, fd4 = -1, fd6 = -1;
 
 shost.next = NULL;
@@ -288,9 +416,7 @@ namelen = Ustrlen(hostname);
 if (hostname[0] == '[' &&
     hostname[namelen - 1] == ']')
   {
-  uschar * host = string_copy(hostname);
-  host[namelen - 1] = 0;
-  host++;
+  uschar * host = string_copyn(hostname+1, namelen-2);
   if (string_is_ip_address(host, NULL) == 0)
     {
     *errstr = string_sprintf("malformed IP address \"%s\"", hostname);
@@ -302,15 +428,15 @@ if (hostname[0] == '[' &&
 /* Otherwise check for an unadorned IP address */
 
 else if (string_is_ip_address(hostname, NULL) != 0)
-  shost.name = shost.address = string_copy(hostname);
+  shost.name = shost.address = string_copyn(hostname, namelen);
 
 /* Otherwise lookup IP address(es) from the name */
 
 else
   {
-  shost.name = string_copy(hostname);
-  if (host_find_byname(&shost, NULL, HOST_FIND_QUALIFY_SINGLE, NULL,
-      FALSE) != HOST_FOUND)
+  shost.name = string_copyn(hostname, namelen);
+  if (host_find_byname(&shost, NULL, HOST_FIND_QUALIFY_SINGLE,
+      NULL, FALSE) != HOST_FOUND)
     {
     *errstr = string_sprintf("no IP address found for host %s", shost.name);
     return -1;
@@ -319,11 +445,11 @@ else
 
 /* Try to connect to the server - test each IP till one works */
 
-for (h = &shost; h != NULL; h = h->next)
+for (host_item * h = &shost; h; h = h->next)
   {
-  fd = (Ustrchr(h->address, ':') != 0)
-    ? (fd6 < 0) ? (fd6 = ip_socket(type, af = AF_INET6)) : fd6
-    : (fd4 < 0) ? (fd4 = ip_socket(type, af = AF_INET )) : fd4;
+  fd = Ustrchr(h->address, ':') != 0
+    ? fd6 < 0 ? (fd6 = ip_socket(type, af = AF_INET6)) : fd6
+    : fd4 < 0 ? (fd4 = ip_socket(type, af = AF_INET )) : fd4;
 
   if (fd < 0)
     {
@@ -331,8 +457,8 @@ for (h = &shost; h != NULL; h = h->next)
     goto bad;
     }
 
-  for(port = portlo; port <= porthi; port++)
-    if (ip_connect(fd, af, h->address, port, timeout) == 0)
+  for (int port = portlo; port <= porthi; port++)
+    if (ip_connect(fd, af, h->address, port, timeout, fastopen_blob) == 0)
       {
       if (fd != fd6) close(fd6);
       if (fd != fd4) close(fd4);
@@ -354,6 +480,7 @@ bad:
 }
 
 
+/*XXX TFO? */
 int
 ip_tcpsocket(const uschar * hostport, uschar ** errstr, int tmo)
 {
@@ -374,7 +501,7 @@ if (scan != 3)
   }
 
 return ip_connectedsocket(SOCK_STREAM, hostname, portlow, porthigh,
-			  tmo, NULL, errstr);
+			  tmo, NULL, errstr, NULL);
 }
 
 int
@@ -389,8 +516,9 @@ if ((sock = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
   return -1;
   }
 
+callout_address = string_copy(path);
 server.sun_family = AF_UNIX;
-Ustrncpy(server.sun_path, path, sizeof(server.sun_path)-1);
+Ustrncpy(US server.sun_path, path, sizeof(server.sun_path)-1);
 server.sun_path[sizeof(server.sun_path)-1] = '\0';
 if (connect(sock, (struct sockaddr *) &server, sizeof(server)) < 0)
   {
@@ -403,6 +531,10 @@ if (connect(sock, (struct sockaddr *) &server, sizeof(server)) < 0)
 return sock;
 }
 
+/* spec is either an absolute path (with a leading /), or
+a host (name or IP) and port (whitespace-separated).
+The port can be a range, dash-separated, or a single number.
+*/
 int
 ip_streamsocket(const uschar * spec, uschar ** errstr, int tmo)
 {
@@ -429,7 +561,7 @@ ip_keepalive(int sock, const uschar *address, BOOL torf)
 {
 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));
 }
@@ -443,19 +575,18 @@ if (setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
 /*
 Arguments:
   fd          the file descriptor
-  timeout     the timeout, seconds
+  timelimit   the timeout endpoint, seconds-since-epoch
 Returns:      TRUE => ready for i/o
               FALSE => timed out, or other error
 */
 BOOL
-fd_ready(int fd, int timeout)
+fd_ready(int fd, time_t timelimit)
 {
 fd_set select_inset;
-struct timeval tv;
-time_t start_recv = time(NULL);
+int time_left = timelimit - time(NULL);
 int rc;
 
-if (timeout <= 0)
+if (time_left <= 0)
   {
   errno = ETIMEDOUT;
   return FALSE;
@@ -464,10 +595,9 @@ if (timeout <= 0)
 
 do
   {
+  struct timeval tv = { .tv_sec = time_left, .tv_usec = 0 };
   FD_ZERO (&select_inset);
   FD_SET (fd, &select_inset);
-  tv.tv_sec = timeout;
-  tv.tv_usec = 0;
 
   /*DEBUG(D_transport) debug_printf("waiting for data on fd\n");*/
   rc = select(fd + 1, (SELECT_ARG2_TYPE *)&select_inset, NULL, NULL, &tv);
@@ -479,17 +609,16 @@ do
   Aug 2004: Somebody set up a cron job that ran exiwhat every 2 minutes, making
   the interrupt not at all rare. Since the timeout is typically more than 2
   minutes, the effect was to block the timeout completely. To prevent this
-  happening again, we do an explicit time test. */
+  happening again, we do an explicit time test and adjust the timeout
+  accordingly */
 
   if (rc < 0 && errno == EINTR)
     {
     DEBUG(D_transport) debug_printf("EINTR while waiting for socket data\n");
-    if (time(NULL) - start_recv < timeout) continue;
-    DEBUG(D_transport) debug_printf("total wait time exceeds timeout\n");
-    }
 
-  /* Handle a timeout, and treat any other select error as a timeout, including
-  an EINTR when we have been in this loop for longer than timeout. */
+    /* Watch out, 'continue' jumps to the condition, not to the loops top */
+    if ((time_left = timelimit - time(NULL)) > 0) continue;
+    }
 
   if (rc <= 0)
     {
@@ -497,9 +626,10 @@ do
     return FALSE;
     }
 
-  /* If the socket is ready, break out of the loop. */
+  /* Checking the FD_ISSET is not enough, if we're interrupted, the
+  select_inset may still contain the 'input'. */
   }
-while (!FD_ISSET(fd, &select_inset));
+while (rc < 0 || !FD_ISSET(fd, &select_inset));
 return TRUE;
 }
 
@@ -508,34 +638,34 @@ getting interrupted, and the possibility of select() returning with a positive
 result but no ready descriptor. Is this in fact possible?
 
 Arguments:
-  sock        the socket
+  cctx        the connection context (socket fd, possibly TLS context)
   buffer      to read into
   bufsize     the buffer size
-  timeout     the timeout
+  timelimit   the timeout endpoint, seconds-since-epoch
 
 Returns:      > 0 => that much data read
               <= 0 on error or EOF; errno set - zero for EOF
 */
 
 int
-ip_recv(int sock, uschar *buffer, int buffsize, int timeout)
+ip_recv(client_conn_ctx * cctx, uschar * buffer, int buffsize, time_t timelimit)
 {
 int rc;
 
-if (!fd_ready(sock, timeout))
+if (!fd_ready(cctx->sock, timelimit))
   return -1;
 
 /* The socket is ready, read from it (via TLS if it's active). On EOF (i.e.
 close down of the connection), set errno to zero; otherwise leave it alone. */
 
-#ifdef SUPPORT_TLS
-if (tls_out.active == sock)
-  rc = tls_read(FALSE, buffer, buffsize);
-else if (tls_in.active == sock)
-  rc = tls_read(TRUE, buffer, buffsize);
+#ifndef DISABLE_TLS
+if (cctx->tls_ctx)					/* client TLS */
+  rc = tls_read(cctx->tls_ctx, buffer, buffsize);
+else if (tls_in.active.sock == cctx->sock)		/* server TLS */
+  rc = tls_read(NULL, buffer, buffsize);
 else
 #endif
-  rc = recv(sock, buffer, buffsize, 0);
+  rc = recv(cctx->sock, buffer, buffsize, 0);
 
 if (rc > 0) return rc;
 if (rc == 0) errno = 0;
@@ -712,8 +842,7 @@ return FALSE;
 void
 dscp_list_to_stream(FILE *stream)
 {
-int i;
-for (i=0; i < dscp_table_size; ++i)
+for (int i = 0; i < dscp_table_size; ++i)
   fprintf(stream, "%s\n", dscp_table[i].name);
 }