udhcpc6: add DHCPv6 env helper

Add string_option_to_env() to easily generate environment variables for
known simple options.

Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/networking/udhcp/d6_dhcpc.c b/networking/udhcp/d6_dhcpc.c
index 85d9da724a21b92f8d18adf4b8b502a6ea2a2c1b..fa1568b5f23c26e9a367f67d442f548fab8c1dbd 100644 (file)
--- a/networking/udhcp/d6_dhcpc.c
+++ b/networking/udhcp/d6_dhcpc.c
@@ -195,6 +195,34 @@ static char** new_env(void)
        return &client6_data.env_ptr[client6_data.env_idx++];
 }
 
+static char *string_option_to_env(uint8_t *option, uint8_t *option_end)
+{
+       const char *ptr, *name = NULL;
+       unsigned val_len;
+       int i;
+
+       ptr = d6_option_strings;
+       i = 0;
+       while (*ptr) {
+               if (d6_optflags[i].code == option[1]) {
+                       name = ptr;
+                       goto found;
+               }
+               ptr += strlen(ptr) + 1;
+               i++;
+       }
+       bb_error_msg("can't find option name for 0x%x, skipping", option[1]);
+       return NULL;
+
+ found:
+       val_len = (option[2] << 8) | option[3];
+       if (val_len + &option[D6_OPT_DATA] > option_end) {
+               bb_error_msg("option data exceeds option length");
+               return NULL;
+       }
+       return xasprintf("%s=%.*s", name, val_len, (char*)option + 4);
+}
+
 /* put all the parameters into the environment */
 static void option_to_env(uint8_t *option, uint8_t *option_end)
 {