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-rw-r--r--libc/inet/resolv.c52
1 files changed, 52 insertions, 0 deletions
diff --git a/libc/inet/resolv.c b/libc/inet/resolv.c
index a74ab30af..6bfe52c79 100644
--- a/libc/inet/resolv.c
+++ b/libc/inet/resolv.c
@@ -3348,6 +3348,58 @@ int ns_name_compress(const char *src,
return ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr);
}
+
+int ns_name_skip(const unsigned char **ptrptr,
+ const unsigned char *eom)
+{
+ const unsigned char *cp;
+ u_int n;
+ int l;
+
+ cp = *ptrptr;
+ while (cp < eom && (n = *cp++) != 0) {
+ /* Check for indirection. */
+ switch (n & NS_CMPRSFLGS) {
+ case 0: /*%< normal case, n == len */
+ cp += n;
+ continue;
+ case NS_TYPE_ELT: /*%< EDNS0 extended label */
+ if ((l = labellen(cp - 1)) < 0) {
+ errno = EMSGSIZE; /*%< XXX */
+ return -1;
+ }
+ cp += l;
+ continue;
+ case NS_CMPRSFLGS: /*%< indirection */
+ cp++;
+ break;
+ default: /*%< illegal type */
+ errno = EMSGSIZE;
+ return -1;
+ }
+
+ break;
+ }
+
+ if (cp > eom) {
+ errno = EMSGSIZE;
+ return -1;
+ }
+
+ *ptrptr = cp;
+
+ return 0;
+}
+
+int dn_skipname(const unsigned char *ptr, const unsigned char *eom)
+{
+ const unsigned char *saveptr = ptr;
+
+ if (ns_name_skip(&ptr, eom) == -1)
+ return -1;
+
+ return ptr - saveptr;
+}
#endif /* L_ns_name */