Changeset f1dcf6d in mainline for uspace/srv/net/dnsres/dns_msg.c

Timestamp:

2013-04-20T09:38:59Z (11 years ago)

Author:

Jiri Svoboda <jiri@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

7262f89

Parents:

9d8bd3ac

Message:

Pointer decoding.

File:

• uspace/srv/net/dnsres/dns_msg.c (modified) (4 diffs)

uspace/srv/net/dnsres/dns_msg.c

@@ -47 +47 @@
 #define NAME  "dnsres"
 
+static uint16_t dns_uint16_t_decode(uint8_t *, size_t);
+
 #include <stdio.h>
 static int dns_name_encode(char *name, uint8_t *buf, size_t buf_size,
@@ -117 +119 @@
         size_t lsize;
         size_t i;
+        size_t ptr;
+        size_t eptr;
 
         if (boff > size)
@@ -129 +133 @@
                 }
 
-
                 lsize = *bp;
                 ++bp;
@@ -137 +140 @@
                         break;
 
-                if (bp != buf + 1)
+                if (bp != buf + boff + 1)
                         printf(".");
 
                 if ((lsize & 0xc0) == 0xc0) {
+                        printf("Pointer\n");
                         /* Pointer */
-                        printf("compression not supported!\n");
-                        return EINVAL;
+                        if (bsize < 1) {
+                                printf("Pointer- bsize < 1\n");
+                                return EINVAL;
+                        }
+
+                        ptr = dns_uint16_t_decode(bp - 1, bsize) & 0x3fff;
+                        if (ptr >= (size_t)(bp - buf)) {
+                                printf("Pointer- forward ref %u, pos=%u\n",
+                                    ptr, bp - buf);
+                                /* Forward reference */
+                                return EINVAL;
+                        }
+
+                        /*
+                         * Make sure we will not decode any byte twice.
+                         * XXX Is assumption correct?
+                         */
+                        eptr = buf - bp;
+
+                        printf("ptr=%u, eptr=%u\n", ptr, eptr);
+                        bp = buf + ptr;
+                        bsize = eptr - ptr;
+                        continue;
                 }