From aab9f46b0488e0dd80c728b6d642fa4de853e63f Mon Sep 17 00:00:00 2001
From: Philipp Tölke <toelke@in.tum.de>
Date: Fri, 29 Apr 2011 13:13:54 +0000
Subject: handle the reception of dns-answers in daemon-vpn

---
 src/vpn/gnunet-daemon-vpn.c | 77 ++++++++++++++++++++++++++++++++++++++++++++-
 src/vpn/gnunet-daemon-vpn.h |  4 +++
 2 files changed, 80 insertions(+), 1 deletion(-)

diff --git a/src/vpn/gnunet-daemon-vpn.c b/src/vpn/gnunet-daemon-vpn.c
index 726a013c0..6829b3cd9 100644
--- a/src/vpn/gnunet-daemon-vpn.c
+++ b/src/vpn/gnunet-daemon-vpn.c
@@ -236,6 +236,34 @@ new_ip6addr(unsigned char* buf, const GNUNET_HashCode *peer, const GNUNET_HashCo
 }
 /*}}}*/
 
+/**
+ * Create a new Address from an answer-packet
+ */
+void
+new_ip6addr_remote (unsigned char *buf, unsigned char *addr, char addrlen)
+{                               /* {{{ */
+  char *ipv6addr;
+  unsigned long long ipv6prefix;
+  GNUNET_assert (GNUNET_OK ==
+                 GNUNET_CONFIGURATION_get_value_string (cfg, "vpn",
+                                                        "IPV6ADDR",
+                                                        &ipv6addr));
+  GNUNET_assert (GNUNET_OK ==
+                 GNUNET_CONFIGURATION_get_value_number (cfg, "vpn",
+                                                        "IPV6PREFIX",
+                                                        &ipv6prefix));
+  GNUNET_assert (ipv6prefix < 127);
+  ipv6prefix = (ipv6prefix + 7) / 8;
+
+  inet_pton (AF_INET6, ipv6addr, buf);
+  GNUNET_free (ipv6addr);
+
+  int local_length = 16 - ipv6prefix;
+
+  memcpy (buf + ipv6prefix, addr, max (addrlen, local_length));
+}
+/*}}}*/
+
 /**
  * This gets scheduled with cls pointing to an answer_packet and does everything
  * needed in order to send it to the helper.
@@ -360,7 +388,54 @@ process_answer(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tc) {
 	list = GNUNET_malloc(htons(pkt->hdr.size) + 2*sizeof(struct answer_packet_list*));
 	memcpy(&list->pkt, pkt, htons(pkt->hdr.size));
       }
-    /* TODO GNUNET_DNS_ANSWER_TYPE_REMOTE */
+    else if (pkt->subtype == GNUNET_DNS_ANSWER_TYPE_REMOTE)
+      {
+	pkt->subtype = GNUNET_DNS_ANSWER_TYPE_IP;
+
+	GNUNET_HashCode key;
+	memset(&key, 0, sizeof(GNUNET_HashCode));
+
+	unsigned char* c = ((unsigned char*)pkt)+ntohs(pkt->addroffset);
+        new_ip6addr_remote(c, &pkt->addr, pkt->addrsize);
+	unsigned char* k = (unsigned char*)&key;
+	/*
+	 * Copy the newly generated ip-address to the key backwards (as only the first part is used in the hash-table)
+	 */
+	unsigned int i;
+	for (i = 0; i < 16; i++)
+	    k[15-i] = c[i];
+
+	uint16_t namelen = strlen((char*)pkt->data+12)+1;
+
+	struct map_entry* value = GNUNET_malloc(sizeof(struct map_entry) + namelen);
+	char* name = (char*)(value +1);
+
+	value->namelen = namelen;
+	memcpy(name, pkt->data+12, namelen);
+
+        value->addrlen = pkt->addrsize;
+        memcpy(&value->addr, &pkt->addr, pkt->addrsize);
+        memset(value->additional_ports, 0, 8192);
+
+        memcpy(&value->hash, &key, sizeof(GNUNET_HashCode));
+
+        if (GNUNET_NO ==
+            GNUNET_CONTAINER_multihashmap_contains (hashmap, &key))
+          {
+            GNUNET_CONTAINER_multihashmap_put (hashmap, &key, value,
+                                               GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY);
+            value->heap_node = GNUNET_CONTAINER_heap_insert (heap, value,
+                                                             GNUNET_TIME_absolute_get ().abs_value);
+            if (GNUNET_CONTAINER_heap_get_size(heap) > max_mappings)
+              GNUNET_SCHEDULER_add_now(collect_mappings, NULL);
+          }
+        else
+          GNUNET_free(value);
+
+	list = GNUNET_malloc(htons(pkt->hdr.size) + 2*sizeof(struct answer_packet_list*));
+
+	memcpy(&list->pkt, pkt, htons(pkt->hdr.size));
+      }
     else
       {
 	GNUNET_break(0);
diff --git a/src/vpn/gnunet-daemon-vpn.h b/src/vpn/gnunet-daemon-vpn.h
index 11d3fa43b..3ddd6eef6 100644
--- a/src/vpn/gnunet-daemon-vpn.h
+++ b/src/vpn/gnunet-daemon-vpn.h
@@ -70,6 +70,10 @@ extern struct GNUNET_CONTAINER_MultiHashMap* hashmap;
 
 struct map_entry {
     struct GNUNET_vpn_service_descriptor desc;
+
+    char addrlen;
+    char addr[16];
+
     struct GNUNET_MESH_Tunnel *tunnel;
     uint16_t namelen;
     char additional_ports[8192];
-- 
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