udhcp: comment out unused domain compression code

function                                             old     new   delta
attach_option                                        411     406      -5
dname_enc                                            381     167    -214
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-219)           Total: -219 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

3 files changed, 18 insertions, 13 deletions

diff --git a/networking/udhcp/common.c b/networking/udhcp/common.c
index 9ec752dfc..16bf69707 100644
--- a/networking/udhcp/common.c
+++ b/networking/udhcp/common.c
@@ -431,7 +431,7 @@ static NOINLINE void attach_option(
 #if ENABLE_FEATURE_UDHCP_RFC3397
         if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_DNS_STRING) {
                 /* reuse buffer and length for RFC1035-formatted string */
-                allocated = buffer = (char *)dname_enc(NULL, 0, buffer, &length);
+                allocated = buffer = (char *)dname_enc(/*NULL, 0,*/ buffer, &length);
         }
 #endif
 
diff --git a/networking/udhcp/common.h b/networking/udhcp/common.h
index 60255eefa..73f860a77 100644
--- a/networking/udhcp/common.h
+++ b/networking/udhcp/common.h
@@ -218,7 +218,7 @@ void udhcp_add_simple_option(struct dhcp_packet *packet, uint8_t code, uint32_t
 #endif
 #if ENABLE_FEATURE_UDHCP_RFC3397 || ENABLE_FEATURE_UDHCPC6_RFC3646 || ENABLE_FEATURE_UDHCPC6_RFC4704
 char *dname_dec(const uint8_t *cstr, int clen, const char *pre) FAST_FUNC;
-uint8_t *dname_enc(const uint8_t *cstr, int clen, const char *src, int *retlen) FAST_FUNC;
+uint8_t *dname_enc(/*const uint8_t *cstr, int clen,*/ const char *src, int *retlen) FAST_FUNC;
 #endif
 struct option_set *udhcp_find_option(struct option_set *opt_list, uint8_t code) FAST_FUNC;
 
diff --git a/networking/udhcp/domain_codec.c b/networking/udhcp/domain_codec.c
index b7a3a5353..752c0a863 100644
--- a/networking/udhcp/domain_codec.c
+++ b/networking/udhcp/domain_codec.c
@@ -109,11 +109,11 @@ char* FAST_FUNC dname_dec(const uint8_t *cstr, int clen, const char *pre)
         return ret;
 }
 
-/* Convert a domain name (src) from human-readable "foo.blah.com" format into
+/* Convert a domain name (src) from human-readable "foo.BLAH.com" format into
  * RFC1035 encoding "\003foo\004blah\003com\000". Return allocated string, or
  * NULL if an error occurs.
  */
-static uint8_t *convert_dname(const char *src)
+static uint8_t *convert_dname(const char *src, int *retlen)
 {
         uint8_t c, *res, *lenptr, *dst;
         int len;
@@ -129,6 +129,7 @@ static uint8_t *convert_dname(const char *src)
                         /* label too long, too short, or two '.'s in a row? abort */
                         if (len > NS_MAXLABEL || len == 0 || (c == '.' && *src == '.')) {
                                 free(res);
+                                *retlen = 0;
                                 return NULL;
                         }
                         *lenptr = len;
@@ -144,13 +145,16 @@ static uint8_t *convert_dname(const char *src)
 
         if (dst - res >= NS_MAXCDNAME) {  /* dname too long? abort */
                 free(res);
+                *retlen = 0;
                 return NULL;
         }
 
-        *dst = 0;
+        *dst++ = 0;
+        *retlen = dst - res;
         return res;
 }
 
+#if 0 //UNUSED
 /* Returns the offset within cstr at which dname can be found, or -1 */
 static int find_offset(const uint8_t *cstr, int clen, const uint8_t *dname)
 {
@@ -188,28 +192,27 @@ static int find_offset(const uint8_t *cstr, int clen, const uint8_t *dname)
 
         return -1;
 }
+#endif
 
+uint8_t* FAST_FUNC dname_enc(/*const uint8_t *cstr, int clen,*/ const char *src, int *retlen)
+{
+#if 0 //UNUSED, was intended for long, repetitive DHCP_DOMAIN_SEARCH options?
+        uint8_t *d, *dname;
 /* Computes string to be appended to cstr so that src would be added to
  * the compression (best case, it's a 2-byte pointer to some offset within
  * cstr; worst case, it's all of src, converted to <4>host<3>com<0> format).
  * The computed string is returned directly; its length is returned via retlen;
  * NULL and 0, respectively, are returned if an error occurs.
  */
-uint8_t* FAST_FUNC dname_enc(const uint8_t *cstr, int clen, const char *src, int *retlen)
-{
-        uint8_t *d, *dname;
-        int off;
-
-        dname = convert_dname(src);
+        dname = convert_dname(src, retlen);
         if (dname == NULL) {
-                *retlen = 0;
                 return NULL;
         }
 
         d = dname;
         while (*d) {
                 if (cstr) {
-                        off = find_offset(cstr, clen, d);
+                        int off = find_offset(cstr, clen, d);
                         if (off >= 0) { /* found a match, add pointer and return */
                                 *d++ = NS_CMPRSFLGS | (off >> 8);
                                 *d = off;
@@ -221,6 +224,8 @@ uint8_t* FAST_FUNC dname_enc(const uint8_t *cstr, int clen, const char *src, int
 
         *retlen = d - dname + 1;
         return dname;
+#endif
+        return convert_dname(src, retlen);
 }
 
 #ifdef DNS_COMPR_TESTING