[U-Boot] [Patch] ./net/net.c - make Microsoft dns servers happy with random_port() numbers
For some reason, (which I can't find any documentation on), if U-Boot gives a port number higher than 17500 to a Microsoft DNS server, the server will reply to port 17500, and U-Boot will ignore things (since that isn't the port it asked the DNS server to reply to).
This fixes that by ensuring the random port number is less than 17500.
Signed-off-by: Robin Getz rgetz@blackfin.uclinux.org
--- net/net.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/net.c b/net/net.c index 595abd9..98d58e5 100644 --- a/net/net.c +++ b/net/net.c @@ -1872,11 +1872,13 @@ void copy_filename (char *dst, char *src, int size)
#if defined(CONFIG_CMD_NFS) || defined(CONFIG_CMD_SNTP) || defined(CONFIG_CMD_DNS) /* - * make port a little random, but use something trivial to compute + * make port a little random (1024-17407) + * This keeps the math somewhat trivial to compute, and seems to work with + * all supported protocols/clients/servers */ unsigned int random_port(void) { - return 1024 + (get_timer(0) % 0x8000);; + return 1024 + (get_timer(0) % 0x4000); } #endif
Hi Robin,
For some reason, (which I can't find any documentation on), if U-Boot gives a port number higher than 17500 to a Microsoft DNS server, the server will reply to port 17500, and U-Boot will ignore things (since that isn't the port it asked the DNS server to reply to).
This fixes that by ensuring the random port number is less than 17500.
Can you please put such a comment also in the code? I believe this to be useful information when studying the code and not only when going through changelogs.
Thanks Detlev
Hi Robin,
On 3/8/2010 11:07 AM, Robin Getz wrote:
For some reason, (which I can't find any documentation on), if U-Boot gives a port number higher than 17500 to a Microsoft DNS server, the server will reply to port 17500, and U-Boot will ignore things (since that isn't the port it asked the DNS server to reply to).
This fixes that by ensuring the random port number is less than 17500.
Signed-off-by: Robin Getzrgetz@blackfin.uclinux.org
net/net.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/net.c b/net/net.c index 595abd9..98d58e5 100644 --- a/net/net.c +++ b/net/net.c @@ -1872,11 +1872,13 @@ void copy_filename (char *dst, char *src, int size)
#if defined(CONFIG_CMD_NFS) || defined(CONFIG_CMD_SNTP) || defined(CONFIG_CMD_DNS) /*
- make port a little random, but use something trivial to compute
- make port a little random (1024-17407)
- This keeps the math somewhat trivial to compute, and seems to work with
*/ unsigned int random_port(void) {
- all supported protocols/clients/servers
- return 1024 + (get_timer(0) % 0x8000);;
- return 1024 + (get_timer(0) % 0x4000); } #endif
Applied to net repo.
thanks, Ben
participants (3)
-
Ben Warren -
Detlev Zundel -
Robin Getz