udhcp: implement "raw" binary options. Closes bug 735

function                                             old     new   delta
allocate_tempopt_if_needed                             -      76     +76
udhcp_str2optset                                     351     415     +64
attach_option                                        380     398     +18
len_of_option_as_string                               11      12      +1
dhcp_option_lengths                                   11      12      +1
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 4/0 up/down: 160/0)             Total: 160 bytes

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

2 files changed, 43 insertions, 13 deletions

diff --git a/networking/udhcp/common.c b/networking/udhcp/common.c
index fb4f8d16c..50e2c84e3 100644
--- a/networking/udhcp/common.c
+++ b/networking/udhcp/common.c
@@ -324,9 +324,27 @@ int FAST_FUNC udhcp_str2nip(const char *str, void *arg)
 }
 
 /* udhcp_str2optset:
- * Parse string option representation to binary form
- * and add it to opt_list
+ * Parse string option representation to binary form and add it to opt_list.
+ * Called to parse "udhcpc -x OPTNAME:OPTVAL"
+ * and to parse udhcpd.conf's "opt OPTNAME OPTVAL" directives.
  */
+/* helper for the helper */
+static char *allocate_tempopt_if_needed(
+                const struct dhcp_optflag *optflag,
+                char *buffer,
+                int *length_p)
+{
+        char *allocated = NULL;
+        if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_BIN) {
+                const char *end;
+                allocated = xstrdup(buffer); /* more than enough */
+                end = hex2bin(allocated, buffer, 255);
+                if (errno)
+                        bb_error_msg_and_die("malformed hex string '%s'", buffer);
+                *length_p = end - allocated;
+        }
+        return allocated;
+}
 /* helper: add an option to the opt_list */
 static NOINLINE void attach_option(
                 struct option_set **opt_list,
@@ -335,13 +353,12 @@ static NOINLINE void attach_option(
                 int length)
 {
         struct option_set *existing, *new, **curr;
-#if ENABLE_FEATURE_UDHCP_RFC3397
         char *allocated = NULL;
-#endif
 
         existing = udhcp_find_option(*opt_list, optflag->code);
         if (!existing) {
                 log2("Attaching option %02x to list", optflag->code);
+                allocated = allocate_tempopt_if_needed(optflag, buffer, &length);
 #if ENABLE_FEATURE_UDHCP_RFC3397
                 if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_DNS_STRING) {
                         /* reuse buffer and length for RFC1035-formatted string */
@@ -368,7 +385,8 @@ static NOINLINE void attach_option(
                 unsigned old_len;
 
                 /* add it to an existing option */
-                log1("Attaching option %02x to existing member of list", optflag->code);
+                log2("Attaching option %02x to existing member of list", optflag->code);
+                allocated = allocate_tempopt_if_needed(optflag, buffer, &length);
                 old_len = existing->data[OPT_LEN];
 #if ENABLE_FEATURE_UDHCP_RFC3397
                 if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_DNS_STRING) {
@@ -390,10 +408,8 @@ static NOINLINE void attach_option(
                 } /* else, ignore the data, we could put this in a second option in the future */
         } /* else, ignore the new data */
 
- ret: ;
-#if ENABLE_FEATURE_UDHCP_RFC3397
+ ret:
         free(allocated);
-#endif
 }
 
 int FAST_FUNC udhcp_str2optset(const char *const_str, void *arg)
@@ -402,6 +418,8 @@ int FAST_FUNC udhcp_str2optset(const char *const_str, void *arg)
         char *opt, *val, *endptr;
         char *str;
         const struct dhcp_optflag *optflag;
+        struct dhcp_optflag bin_optflag;
+        unsigned optcode;
         int retval, length;
         char buffer[8] ALIGNED(4);
         uint16_t *result_u16 = (uint16_t *) buffer;
@@ -413,7 +431,15 @@ int FAST_FUNC udhcp_str2optset(const char *const_str, void *arg)
         if (!opt)
                 return 0;
 
-        optflag = &dhcp_optflags[udhcp_option_idx(opt)];
+        optcode = bb_strtou(opt, NULL, 0);
+        if (!errno && optcode < 255) {
+                /* Raw (numeric) option code */
+                bin_optflag.flags = OPTION_BIN;
+                bin_optflag.code = optcode;
+                optflag = &bin_optflag;
+        } else {
+                optflag = &dhcp_optflags[udhcp_option_idx(opt)];
+        }
 
         retval = 0;
         do {
@@ -482,6 +508,9 @@ int FAST_FUNC udhcp_str2optset(const char *const_str, void *arg)
                         retval = (endptr[0] == '\0');
                         break;
                 }
+                case OPTION_BIN: /* handled in attach_option() */
+                        opt = val;
+                        retval = 1;
                 default:
                         break;
                 }
diff --git a/networking/udhcp/common.h b/networking/udhcp/common.h
index 7dd1f119a..c9dd0bb25 100644
--- a/networking/udhcp/common.h
+++ b/networking/udhcp/common.h
@@ -70,17 +70,18 @@ enum {
         OPTION_IP = 1,
         OPTION_IP_PAIR,
         OPTION_STRING,
-#if ENABLE_FEATURE_UDHCP_RFC3397
-        OPTION_DNS_STRING,  /* RFC1035 compressed domain name list */
-        OPTION_SIP_SERVERS,
-#endif
 //      OPTION_BOOLEAN,
         OPTION_U8,
         OPTION_U16,
 //      OPTION_S16,
         OPTION_U32,
         OPTION_S32,
+        OPTION_BIN,
         OPTION_STATIC_ROUTES,
+#if ENABLE_FEATURE_UDHCP_RFC3397
+        OPTION_DNS_STRING,  /* RFC1035 compressed domain name list */
+        OPTION_SIP_SERVERS,
+#endif
 
         OPTION_TYPE_MASK = 0x0f,
         /* Client requests this option by default */