diff options
| author | Gerhard Sittig <gsi@denx.de> | 2014-09-12 08:48:15 +0200 |
|---|---|---|
| committer | Tom Rini <trini@ti.com> | 2014-09-16 12:24:00 -0400 |
| commit | f395e75e27323cc1ef060f640d0d535ed50e705d (patch) | |
| tree | 0c514fa5927a04787543e78ccf148734714c7905 /net/dns.c | |
| parent | 11b5db67879c1ac0f1c358fb9b791896af189b0a (diff) | |
net: dns: fix for DNS queries sent to the wrong MAC address
When a DNS query is sent out, the ethernet packet can get directed to
the MAC address of a server that was communicated to before. This is
wrong when the previously stored MAC address corresponds to a different
server's IP address, i.e. when the IP address of the previous and the
current communication are different.
The error can get reproduced by running a sequence of e.g. a TFTP
download and a DNS query, where the TFTP and DNS servers reside on
individual machines.
The fix is to clear the server's MAC address that might be left from a
previous operation, and to fetch the peer's MAC address in a new ARP
lookup, before the DNS query is sent. This is the approach taken in
other network services, like 8e52533d1095 ("net: tftpsrv: Get correct
client MAC address").
Reported-by: Dirk Zimoch <dirk.zimoch@psi.ch>
Signed-off-by: Gerhard Sittig <gsi@denx.de>
Diffstat (limited to 'net/dns.c')
| -rw-r--r-- | net/dns.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/dns.c b/net/dns.c index ff9ddffc9d0..dd453201504 100644 --- a/net/dns.c +++ b/net/dns.c @@ -202,5 +202,8 @@ DnsStart(void) NetSetTimeout(DNS_TIMEOUT, DnsTimeout); net_set_udp_handler(DnsHandler); + /* Clear a previous MAC address, the server IP might have changed. */ + memset(NetServerEther, 0, sizeof(NetServerEther)); + DnsSend(); } |