dns: don't get stuck on no packet received

Make sure the timeout actually gets processed.  The right thing to do
for the receive loop is to check for timeout, then try to receive, and
loop until an acceptable packet has been received; we might as well do
that explicitly.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

diff --git a/core/fs/pxe/dnsresolv.c b/core/fs/pxe/dnsresolv.c
index 76a905a..2b263fa 100644 (file)
--- a/core/fs/pxe/dnsresolv.c
+++ b/core/fs/pxe/dnsresolv.c
@@ -247,7 +247,10 @@ uint32_t dns_resolv(const char *name)
             continue;
 
         oldtime = jiffies();
-       while (1) {
+       do {
+           if (jiffies() - oldtime >= timeout)
+               goto again;
+
             udp_read.status      = 0;
             udp_read.src_ip      = srv;
             udp_read.dest_ip     = IPInfo.myip;
@@ -256,16 +259,8 @@ uint32_t dns_resolv(const char *name)
             udp_read.buffer_size = PKTBUF_SIZE;
             udp_read.buffer      = FAR_PTR(DNSRecvBuf);
             err = pxe_call(PXENV_UDP_READ, &udp_read);
-            if (err || udp_read.status)
-                continue;
-
-            /* Got a packet, deal with it... */
-            if (hd2->id == hd1->id)
-                break;
+       } while (err || udp_read.status || hd2->id != hd1->id);
 
-           if (jiffies() - oldtime >= timeout)
-               goto again;
-        }
         if ((hd2->flags ^ 0x80) & htons(0xf80f))
             goto badness;