Add example for DNS request parsing

diff --git a/plugins/dnsproxy.c b/plugins/dnsproxy.c
index ee65f03..66d608c 100644 (file)
--- a/plugins/dnsproxy.c
+++ b/plugins/dnsproxy.c
@@ -26,6 +26,7 @@
 #include <errno.h>
 #include <unistd.h>
 #include <string.h>
+#include <stdint.h>
 #include <arpa/inet.h>
 #include <netinet/in.h>
 
@@ -235,6 +236,85 @@ static struct connman_resolver dnsproxy_resolver = {
        .remove         = dnsproxy_remove,
 };
 
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+struct domain_hdr {
+       uint16_t id;
+       uint8_t rd:1;
+       uint8_t tc:1;
+       uint8_t aa:1;
+       uint8_t opcode:4;
+       uint8_t qr:1;
+       uint8_t rcode:4;
+       uint8_t z:3;
+       uint8_t ra:1;
+       uint16_t qdcount;
+       uint16_t ancount;
+       uint16_t nscount;
+       uint16_t arcount;
+} __attribute__ ((packed));
+#elif __BYTE_ORDER == __BIG_ENDIAN
+struct domain_hdr {
+       uint16_t id;
+       uint8_t qr:1;
+       uint8_t opcode:4;
+       uint8_t aa:1;
+       uint8_t tc:1;
+       uint8_t rd:1;
+       uint8_t ra:1;
+       uint8_t z:3;
+       uint8_t rcode:4;
+       uint16_t qdcount;
+       uint16_t ancount;
+       uint16_t nscount;
+       uint16_t arcount;
+} __attribute__ ((packed));
+#else
+#error "Unknown byte order"
+#endif
+
+static void parse_request(unsigned char *buf, int len)
+{
+       struct domain_hdr *hdr = (void *) buf;
+       uint16_t qdcount = ntohs(hdr->qdcount);
+       unsigned char *ptr;
+       char name[512];
+       unsigned int remain, used = 0;
+
+       if (len < 12)
+               return;
+
+       DBG("id 0x%04x qr %d opcode %d qdcount %d",
+                               hdr->id, hdr->qr, hdr->opcode, qdcount);
+
+       if (hdr->qr != 0 || qdcount != 1)
+               return;
+
+       memset(name, 0, sizeof(name));
+
+       ptr = buf + 12;
+       remain = len - 12;
+
+       while (remain > 0) {
+               uint8_t len = *ptr;
+
+               if (len == 0x00)
+                       break;
+
+               if (used + len + 1 > sizeof(name))
+                       return;
+
+               strncat(name, (char *) (ptr + 1), len);
+               strcat(name, ".");
+
+               used += len + 1;
+
+               ptr += len + 1;
+               remain -= len + 1;
+       }
+
+       DBG("domain name %s", name);
+}
+
 static gboolean listener_event(GIOChannel *channel, GIOCondition condition,
                                                        gpointer user_data)
 {
@@ -255,6 +335,8 @@ static gboolean listener_event(GIOChannel *channel, GIOCondition condition,
 
        DBG("Received %d bytes (id 0x%04x)", len, buf[0] | buf[1] << 8);
 
+       parse_request(buf, len);
+
        if (g_slist_length(server_list) == 0)
                return TRUE;