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[GNUnet-SVN] r13136 - gnunet/src/vpn
From: |
gnunet |
Subject: |
[GNUnet-SVN] r13136 - gnunet/src/vpn |
Date: |
Sun, 3 Oct 2010 19:24:28 +0200 |
Author: toelke
Date: 2010-10-03 19:24:28 +0200 (Sun, 03 Oct 2010)
New Revision: 13136
Modified:
gnunet/src/vpn/gnunet-daemon-vpn.c
Log:
Hijacking DNS-Traffic works as expected.
Next milestone: responding to .gnunet
Modified: gnunet/src/vpn/gnunet-daemon-vpn.c
===================================================================
--- gnunet/src/vpn/gnunet-daemon-vpn.c 2010-10-03 17:24:27 UTC (rev 13135)
+++ gnunet/src/vpn/gnunet-daemon-vpn.c 2010-10-03 17:24:28 UTC (rev 13136)
@@ -127,9 +127,72 @@
GNUNET_SCHEDULER_add_read_file (mycls.sched,
GNUNET_TIME_UNIT_FOREVER_REL, mycls.fh_from_helper, &helper_read, NULL);
}
+static uint16_t calculate_ip_checksum(uint16_t* hdr, short len) {
+ uint32_t sum = 0;
+ for(; len >= 2; len -= 2)
+ sum += *(hdr++);
+ if (len == 1)
+ sum += *((unsigned char*)hdr);
+
+ sum = (sum >> 16) + (sum & 0xFFFF);
+
+ return ~sum;
+}
+
static void helper_write(void* cls, const struct GNUNET_SCHEDULER_TaskContext*
tsdkctx) {
if (tsdkctx->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
return;
+ struct answer_packet_list* ans = mycls.answer_head;
+ size_t len = ntohs(ans->pkt.hdr.size);
+
+ size_t data_len = len - sizeof(struct answer_packet) + 1;
+ size_t net_len = sizeof(struct ip_hdr) + sizeof(struct udp_dns) +
data_len;
+ size_t pkt_len = sizeof(struct GNUNET_MessageHeader) + sizeof(struct
pkt_tun) + net_len;
+
+ struct ip_udp_dns* pkt = alloca(pkt_len);
+
+ pkt->shdr.size = htons(pkt_len);
+ pkt->shdr.type = htons(GNUNET_MESSAGE_TYPE_VPN_HELPER);
+
+ pkt->tun.flags = 0;
+ pkt->tun.type = htons(0x0800);
+
+ pkt->ip_hdr.version = 4;
+ pkt->ip_hdr.hdr_lngth = 5;
+ pkt->ip_hdr.diff_serv = 0;
+ pkt->ip_hdr.tot_lngth = htons(net_len);
+ pkt->ip_hdr.ident = 0;
+ pkt->ip_hdr.flags = 0;
+ pkt->ip_hdr.frag_off = 0;
+ pkt->ip_hdr.ttl = 255;
+ pkt->ip_hdr.proto = 0x11; /* UDP */
+ pkt->ip_hdr.chks = 0; /* Will be calculated later*/
+ pkt->ip_hdr.sadr = ans->pkt.from;
+ pkt->ip_hdr.dadr = ans->pkt.to;
+
+ pkt->ip_hdr.chks = calculate_ip_checksum((uint16_t*)&pkt->ip_hdr, 5*4);
+
+ pkt->udp_dns.udp_hdr.spt = htons(53);
+ pkt->udp_dns.udp_hdr.dpt = ans->pkt.dst_port;
+ pkt->udp_dns.udp_hdr.len = htons(net_len - sizeof(struct ip_hdr));
+ pkt->udp_dns.udp_hdr.crc = 0; /* Optional for IPv4 */
+
+ memcpy(&pkt->udp_dns.data, ans->pkt.data, data_len);
+
+ /* GNUNET_MessageHeader
+ * pkt_tun
+ * ip_hdr
+ * udp_dns
+ * udp_pkt
+ !!data!!
+ */
+
+ GNUNET_CONTAINER_DLL_remove (mycls.answer_head, mycls.answer_tail, ans);
+ GNUNET_free(ans);
+
+ /* FIXME */ GNUNET_DISK_file_write(mycls.fh_to_helper, pkt, pkt_len);
+
+ /* TODO: if still in dll, reschedule */
}
size_t send_query(void* cls, size_t size, void* buf)
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