TFTP: allow for adjustable retransmission timout
So far, TFTP negotiated a fixed retransmission timeout of 5 seconds.
In some cases (busy networks, slow TFTP servers) this caused very
slow transfers. A new environment variable "tftptimeout" allows to
set this timeout. Lowering this value may make downloads succeed
faster in networks with high packet loss rates or with unreliable
TFTP servers.
Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Ben Warren <biggerbadderben@gmail.com>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>
diff --git a/README b/README
index 1158e24..940b507 100644
--- a/README
+++ b/README
@@ -3005,7 +3005,9 @@
working with an in-memory copy. In case the Flash area containing the
environment is erased by accident, a default environment is provided.
-Some configuration options can be set using Environment Variables:
+Some configuration options can be set using Environment Variables.
+
+List of environment variables (most likely not complete):
baudrate - see CONFIG_BAUDRATE
@@ -3117,7 +3119,7 @@
available network interfaces.
It just stays at the currently selected interface.
- netretry - When set to "no" each network operation will
+ netretry - When set to "no" each network operation will
either succeed or fail without retrying.
When set to "once" the network operation will
fail when all the available network interfaces
@@ -3133,7 +3135,18 @@
tftpdstport - If this is set, the value is used for TFTP's UDP
destination port instead of the Well Know Port 69.
- vlan - When set to a value < 4095 the traffic over
+ tftpblocksize - Block size to use for TFTP transfers; if not set,
+ we use the TFTP server's default block size
+
+ tftptimeout - Retransmission timeout for TFTP packets (in milli-
+ seconds, minimum value is 1000 = 1 second). Defines
+ when a packet is considered to be lost so it has to
+ be retransmitted. The default is 5000 = 5 seconds.
+ Lowering this value may make downloads succeed
+ faster in networks with high packet loss rates or
+ with unreliable TFTP servers.
+
+ vlan - When set to a value < 4095 the traffic over
Ethernet is encapsulated/received over 802.1q
VLAN tagged frames.
diff --git a/net/tftp.c b/net/tftp.c
index a02463b..ed559b7 100644
--- a/net/tftp.c
+++ b/net/tftp.c
@@ -211,7 +211,7 @@
pkt += 5 /*strlen("octet")*/ + 1;
strcpy ((char *)pkt, "timeout");
pkt += 7 /*strlen("timeout")*/ + 1;
- sprintf((char *)pkt, "%lu", TIMEOUT / 1000);
+ sprintf((char *)pkt, "%lu", TftpTimeoutMSecs / 1000);
debug("send option \"timeout %s\"\n", (char *)pkt);
pkt += strlen((char *)pkt) + 1;
#ifdef CONFIG_TFTP_TSIZE
@@ -413,7 +413,6 @@
}
TftpLastBlock = TftpBlock;
- TftpTimeoutMSecs = TIMEOUT;
TftpTimeoutCountMax = TIMEOUT_COUNT;
NetSetTimeout (TftpTimeoutMSecs, TftpTimeout);
@@ -528,10 +527,25 @@
{
char *ep; /* Environment pointer */
- /* Allow the user to choose tftpblocksize */
+ /*
+ * Allow the user to choose TFTP blocksize and timeout.
+ * TFTP protocol has a minimal timeout of 1 second.
+ */
if ((ep = getenv("tftpblocksize")) != NULL)
TftpBlkSizeOption = simple_strtol(ep, NULL, 10);
- debug("tftp block size is %i\n", TftpBlkSizeOption);
+
+ if ((ep = getenv("tftptimeout")) != NULL)
+ TftpTimeoutMSecs = simple_strtol(ep, NULL, 10);
+
+ if (TftpTimeoutMSecs < 1000) {
+ printf("TFTP timeout (%ld ms) too low, "
+ "set minimum = 1000 ms\n",
+ TftpTimeoutMSecs);
+ TftpTimeoutMSecs = 1000;
+ }
+
+ debug("TFTP blocksize = %i, timeout = %ld ms\n",
+ TftpBlkSizeOption, TftpTimeoutMSecs);
TftpServerIP = NetServerIP;
if (BootFile[0] == '\0') {
@@ -588,7 +602,6 @@
puts ("Loading: *\b");
- TftpTimeoutMSecs = TftpRRQTimeoutMSecs;
TftpTimeoutCountMax = TftpRRQTimeoutCountMax;
NetSetTimeout (TftpTimeoutMSecs, TftpTimeout);