Diff: modules/pico_dhcp_common.c

Revision:

2:540f6e142d59

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/pico_dhcp_common.c	Sat Aug 03 13:16:14 2013 +0000
@@ -0,0 +1,67 @@
+/*********************************************************************
+PicoTCP. Copyright (c) 2012 TASS Belgium NV. Some rights reserved.
+See LICENSE and COPYING for usage.
+
+.
+
+Authors: Frederik Van Slycken
+*********************************************************************/
+
+#include "pico_config.h"
+#include "pico_stack.h"
+#include "pico_dhcp_common.h"
+
+#if defined (PICO_SUPPORT_DHCPC) || defined (PICO_SUPPORT_DHCPD)
+//this function should only be used after you checked if the options are valid! otherwise it could read from bad memory!
+uint8_t dhcp_get_next_option(uint8_t *begin, uint8_t *data, int *len, uint8_t **nextopt)
+{
+    uint8_t *p;
+    uint8_t type;
+    uint8_t opt_len;
+
+    if (!begin)
+        p = *nextopt;
+    else
+        p = begin;
+
+    type = *p;
+    *nextopt = ++p;
+    if ((type == PICO_DHCPOPT_END) || (type == PICO_DHCPOPT_PAD)) {
+        memset(data, 0, *len);
+        len = 0;
+        return type;
+    }
+    opt_len = *p;
+    p++;
+    if (*len > opt_len)
+        *len = opt_len;
+    memcpy(data, p, *len);
+    *nextopt = p + opt_len;
+    return type;
+}
+
+int is_options_valid(uint8_t *opt_buffer, int len)
+{
+    uint8_t *p = opt_buffer;
+    while (len > 0) {
+        if (*p == PICO_DHCPOPT_END)
+            return 1;
+        else if (*p == PICO_DHCPOPT_PAD) {
+            p++;
+            len--;
+        } else {
+            uint8_t opt_len;
+            p++;
+            len--;
+            if(len > 0) {
+                opt_len = *p;
+                p += opt_len + 1;
+                len -= opt_len;
+            }else
+                return 0;
+        }
+    }
+    return 0;
+}
+
+#endif