TFTP: add option to suppress TFTP option requests (Part 1)

Some TFTP server implementations ignore the "TFTP Option extension"
(RFC 1782-1784, 2347-2349), or implement it in a flawed way, causing
problems with libcurl. Another switch for curl_easy_setopt
"CURLOPT_TFTP_NO_OPTIONS" is introduced which prevents libcurl from
sending TFTP option requests to a server, avoiding many problems caused
by faulty implementations.

Bug: https://github.com/curl/curl/issues/481

8 files changed, 92 insertions, 29 deletions

diff --git a/docs/libcurl/curl_easy_setopt.3 b/docs/libcurl/curl_easy_setopt.3
index eea407b8c..3a82024a3 100644
--- a/docs/libcurl/curl_easy_setopt.3
+++ b/docs/libcurl/curl_easy_setopt.3
@@ -314,6 +314,8 @@ Authentication address. See \fICURLOPT_MAIL_AUTH(3)\fP
 .SH TFTP OPTIONS
 .IP CURLOPT_TFTP_BLKSIZE
 TFTP block size. See \fICURLOPT_TFTP_BLKSIZE(3)\fP
+.IP CURLOPT_TFTP_NO_OPTIONS
+Prevents TFTP options to be send with RRQs/WRQs. See \fICURLOPT_TFTP_NO_OPTIONS(3)\fP
 .SH FTP OPTIONS
 .IP CURLOPT_FTPPORT
 Use active FTP. See \fICURLOPT_FTPPORT(3)\fP
diff --git a/docs/libcurl/opts/CURLOPT_TFTP_NO_OPTIONS.3 b/docs/libcurl/opts/CURLOPT_TFTP_NO_OPTIONS.3
new file mode 100644
index 000000000..0e31a2937
--- /dev/null
+++ b/docs/libcurl/opts/CURLOPT_TFTP_NO_OPTIONS.3
@@ -0,0 +1,44 @@
+.\" **************************************************************************
+.\" *                                  _   _ ____  _
+.\" *  Project                     ___| | | |  _ \| |
+.\" *                             / __| | | | |_) | |
+.\" *                            | (__| |_| |  _ <| |___
+.\" *                             \___|\___/|_| \_\_____|
+.\" *
+.\" * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" *
+.\" * This software is licensed as described in the file COPYING, which
+.\" * you should have received as part of this distribution. The terms
+.\" * are also available at http://curl.haxx.se/docs/copyright.html.
+.\" *
+.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+.\" * copies of the Software, and permit persons to whom the Software is
+.\" * furnished to do so, under the terms of the COPYING file.
+.\" *
+.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+.\" * KIND, either express or implied.
+.\" *
+.\" **************************************************************************
+.\"
+.TH CURLOPT_TFTP_NO_OPTIONS 3 "19 Jun 2014" "libcurl 7.37.0" "curl_easy_setopt options"
+.SH NAME
+CURLOPT_TFTP_NO_OPTIONS \- Prevents TFTP options to be send with RRQs/WRQs
+.SH SYNOPSIS
+#include <curl/curl.h>
+
+CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TFTP_NO_OPTIONS, long sendoptions);
+.SH DESCRIPTION
+Set \fIsendoptions\fP to 1 to exclude all TFTP options defined in RFC2347,
+RFC2348, RFC2349 from read and write requests.
+libcurl will behave like a client implementing only RFC1350, ignoring any
+protocol extensions.
+.SH DEFAULT
+0
+.SH PROTOCOLS
+TFTP
+.SH EXAMPLE
+TODO
+.SH AVAILABILITY
+Added in 7.48.0
+.SH RETURN VALUE
+Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
diff --git a/docs/libcurl/symbols-in-versions b/docs/libcurl/symbols-in-versions
index 629d2241c..8cfb76521 100644
--- a/docs/libcurl/symbols-in-versions
+++ b/docs/libcurl/symbols-in-versions
@@ -537,6 +537,7 @@ CURLOPT_TCP_KEEPINTVL           7.25.0
 CURLOPT_TCP_NODELAY             7.11.2
 CURLOPT_TELNETOPTIONS           7.7
 CURLOPT_TFTP_BLKSIZE            7.19.4
+CURLOPT_TFTP_NO_OPTIONS         7.48.0
 CURLOPT_TIMECONDITION           7.1
 CURLOPT_TIMEOUT                 7.1
 CURLOPT_TIMEOUT_MS              7.16.2
diff --git a/include/curl/curl.h b/include/curl/curl.h
index 061c570d4..a480bd062 100644
--- a/include/curl/curl.h
+++ b/include/curl/curl.h
@@ -1673,6 +1673,9 @@ typedef enum {
   /* Set E-xclusive stream dependency on another CURL handle */
   CINIT(STREAM_DEPENDS_E, OBJECTPOINT, 241),
 
+  /* Do not send any tftp option requests to the server */
+  CINIT(TFTP_NO_OPTIONS, LONG, 242),
+
   CURLOPT_LASTENTRY /* the last unused */
 } CURLoption;
 
diff --git a/lib/tftp.c b/lib/tftp.c
index 040d967b0..eec774b3e 100644
--- a/lib/tftp.c
+++ b/lib/tftp.c
@@ -494,33 +494,36 @@ static CURLcode tftp_send_first(tftp_state_data_t *state, tftp_event_t event)
              "%s%c%s%c", filename, '\0',  mode, '\0');
     sbytes = 4 + strlen(filename) + strlen(mode);
 
-    /* add tsize option */
-    if(data->set.upload && (data->state.infilesize != -1))
-      snprintf(buf, sizeof(buf), "%" CURL_FORMAT_CURL_OFF_T,
-               data->state.infilesize);
-    else
-      strcpy(buf, "0"); /* the destination is large enough */
-
-    sbytes += tftp_option_add(state, sbytes,
-                              (char *)state->spacket.data+sbytes,
-                              TFTP_OPTION_TSIZE);
-    sbytes += tftp_option_add(state, sbytes,
-                              (char *)state->spacket.data+sbytes, buf);
-    /* add blksize option */
-    snprintf( buf, sizeof(buf), "%d", state->requested_blksize );
-    sbytes += tftp_option_add(state, sbytes,
-                              (char *)state->spacket.data+sbytes,
-                              TFTP_OPTION_BLKSIZE);
-    sbytes += tftp_option_add(state, sbytes,
-                              (char *)state->spacket.data+sbytes, buf );
-
-    /* add timeout option */
-    snprintf( buf, sizeof(buf), "%d", state->retry_time);
-    sbytes += tftp_option_add(state, sbytes,
-                              (char *)state->spacket.data+sbytes,
-                              TFTP_OPTION_INTERVAL);
-    sbytes += tftp_option_add(state, sbytes,
-                              (char *)state->spacket.data+sbytes, buf );
+    /* optional addition of TFTP options */
+    if(!data->set.tftp_no_options) {
+      /* add tsize option */
+      if(data->set.upload && (data->state.infilesize != -1))
+        snprintf(buf, sizeof(buf), "%" CURL_FORMAT_CURL_OFF_T,
+                 data->state.infilesize);
+      else
+        strcpy(buf, "0"); /* the destination is large enough */
+
+      sbytes += tftp_option_add(state, sbytes,
+                                (char *)state->spacket.data+sbytes,
+                                TFTP_OPTION_TSIZE);
+      sbytes += tftp_option_add(state, sbytes,
+                                (char *)state->spacket.data+sbytes, buf);
+      /* add blksize option */
+      snprintf(buf, sizeof(buf), "%d", state->requested_blksize);
+      sbytes += tftp_option_add(state, sbytes,
+                                (char *)state->spacket.data+sbytes,
+                                TFTP_OPTION_BLKSIZE);
+      sbytes += tftp_option_add(state, sbytes,
+                                (char *)state->spacket.data+sbytes, buf );
+
+      /* add timeout option */
+      snprintf(buf, sizeof(buf), "%d", state->retry_time);
+      sbytes += tftp_option_add(state, sbytes,
+                                (char *)state->spacket.data+sbytes,
+                                TFTP_OPTION_INTERVAL);
+      sbytes += tftp_option_add(state, sbytes,
+                                (char *)state->spacket.data+sbytes, buf );
+    }
 
     /* the typecase for the 3rd argument is mostly for systems that do
        not have a size_t argument, like older unixes that want an 'int' */
diff --git a/lib/url.c b/lib/url.c
index 576b8e88c..bf293a4d9 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -843,9 +843,16 @@ CURLcode Curl_setopt(struct SessionHandle *data, CURLoption option,
      */
     data->set.server_response_timeout = va_arg( param , long ) * 1000;
     break;
+  case CURLOPT_TFTP_NO_OPTIONS:
+    /*
+     * Option that prevents libcurl from sending TFTP option requests to the
+     * server.
+     */
+    data->set.tftp_no_options = va_arg(param, long) != 0;
+    break;
   case CURLOPT_TFTP_BLKSIZE:
     /*
-     * TFTP option that specifies the block size to use for data transmission
+     * TFTP option that specifies the block size to use for data transmission.
      */
     data->set.tftp_blksize = va_arg(param, long);
     break;
diff --git a/lib/urldata.h b/lib/urldata.h
index ab26c0111..fcb17561d 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -1499,7 +1499,8 @@ struct UserDefined {
   long connecttimeout;  /* in milliseconds, 0 means no timeout */
   long accepttimeout;   /* in milliseconds, 0 means no timeout */
   long server_response_timeout; /* in milliseconds, 0 means no timeout */
-  long tftp_blksize ; /* in bytes, 0 means use default */
+  long tftp_blksize;    /* in bytes, 0 means use default */
+  bool tftp_no_options; /* do not send TFTP options requests */
   curl_off_t filesize;  /* size of file to upload, -1 means unknown */
   long low_speed_limit; /* bytes/second */
   long low_speed_time;  /* number of seconds */
diff --git a/packages/OS400/curl.inc.in b/packages/OS400/curl.inc.in
index cbb4be703..da3df4ad2 100644
--- a/packages/OS400/curl.inc.in
+++ b/packages/OS400/curl.inc.in
@@ -1242,6 +1242,8 @@
      d                 c                   10240
      d  CURLOPT_STREAM_DEPENDS_E...
      d                 c                   10241
+     d  CURLOPT_TFTP_NO_OPTIONS...
+     d                 c                   10242
       *
       /if not defined(CURL_NO_OLDIES)
      d  CURLOPT_FILE   c                   10001