net/dns.c: Fix endian conversion for big-endian in dns command

net/dns.c used endian conversion macros wrongly (shorts in reply
were put swapped into CPU, and then ntohs() was used to swap it
back, which broke on big-endian).

Fix this by using the correct linux conversion macro for reading
a unaligned short in network byte order: get_unaligned_be16()
Thanks to Mike Frysinger pointing at the best macro to use.

Tested on big and little endian qemu boards (mips and versatile)

Signed-off-by: Bernhard Kaindl <bernhard.kaindl@thalesgroup.com>
Cc: Pieter Voorthuijsen <pieter.voorthuijsen@prodrive.nl>
Cc: Robin Getz <rgetz@blackfin.uclinux.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>

diff --git a/net/dns.c b/net/dns.c
index b51d1bd98220bdea88ef4cebe46a68b9f2ab4756..7a3f1f9768adb18f3043f6fbf2fdeef5d2d7413f 100644 (file)
--- a/net/dns.c
+++ b/net/dns.c
@@ -25,6 +25,7 @@
 #include <common.h>
 #include <command.h>
 #include <net.h>
+#include <asm/unaligned.h>
 
 #include "dns.h"
 
@@ -109,7 +110,6 @@ DnsHandler(uchar *pkt, unsigned dest, IPaddr_t sip, unsigned src, unsigned len)
        int found, stop, dlen;
        char IPStr[22];
        IPaddr_t IPAddress;
-       short tmp;
 
 
        debug("%s\n", __func__);
@@ -120,14 +120,14 @@ DnsHandler(uchar *pkt, unsigned dest, IPaddr_t sip, unsigned src, unsigned len)
                debug("0x%p - 0x%.2x  0x%.2x  0x%.2x  0x%.2x\n",
                        pkt+i, pkt[i], pkt[i+1], pkt[i+2], pkt[i+3]);
 
-       /* We sent 1 query. We want to see more that 1 answer. */
+       /* We sent one query. We want to have a single answer: */
        header = (struct header *) pkt;
        if (ntohs(header->nqueries) != 1)
                return;
 
        /* Received 0 answers */
        if (header->nanswers == 0) {
-               puts("DNS server returned no answers\n");
+               puts("DNS: host not found\n");
                NetState = NETLOOP_SUCCESS;
                return;
        }
@@ -139,9 +139,8 @@ DnsHandler(uchar *pkt, unsigned dest, IPaddr_t sip, unsigned src, unsigned len)
                continue;
 
        /* We sent query class 1, query type 1 */
-       tmp = p[1] | (p[2] << 8);
-       if (&p[5] > e || ntohs(tmp) != DNS_A_RECORD) {
-               puts("DNS response was not A record\n");
+       if (&p[5] > e || get_unaligned_be16(p+1) != DNS_A_RECORD) {
+               puts("DNS: response was not an A record\n");
                NetState = NETLOOP_SUCCESS;
                return;
        }
@@ -160,14 +159,12 @@ DnsHandler(uchar *pkt, unsigned dest, IPaddr_t sip, unsigned src, unsigned len)
                }
                debug("Name (Offset in header): %d\n", p[1]);
 
-               tmp = p[2] | (p[3] << 8);
-               type = ntohs(tmp);
+               type = get_unaligned_be16(p+2);
                debug("type = %d\n", type);
                if (type == DNS_CNAME_RECORD) {
                        /* CNAME answer. shift to the next section */
                        debug("Found canonical name\n");
-                       tmp = p[10] | (p[11] << 8);
-                       dlen = ntohs(tmp);
+                       dlen = get_unaligned_be16(p+10);
                        debug("dlen = %d\n", dlen);
                        p += 12 + dlen;
                } else if (type == DNS_A_RECORD) {
@@ -181,8 +178,7 @@ DnsHandler(uchar *pkt, unsigned dest, IPaddr_t sip, unsigned src, unsigned len)
 
        if (found && &p[12] < e) {
 
-               tmp = p[10] | (p[11] << 8);
-               dlen = ntohs(tmp);
+               dlen = get_unaligned_be16(p+10);
                p += 12;
                memcpy(&IPAddress, p, 4);