BadVPN – Rev 1
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/**
* @file BDHCPClient.c
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <sys/ioctl.h>
#include <linux/filter.h>
#include <misc/debug.h>
#include <misc/byteorder.h>
#include <misc/ethernet_proto.h>
#include <misc/ipv4_proto.h>
#include <misc/udp_proto.h>
#include <misc/dhcp_proto.h>
#include <misc/get_iface_info.h>
#include <base/BLog.h>
#include <dhcpclient/BDHCPClient.h>
#include <generated/blog_channel_BDHCPClient.h>
#define DHCP_SERVER_PORT 67
#define DHCP_CLIENT_PORT 68
#define IPUDP_OVERHEAD (sizeof(struct ipv4_header) + sizeof(struct udp_header))
static const struct sock_filter dhcp_sock_filter[] = {
BPF_STMT(BPF_LD + BPF_B + BPF_ABS, 9), // A <- IP protocol
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPV4_PROTOCOL_UDP, 0, 3), // IP protocol = UDP ?
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 22), // A <- UDP destination port
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_CLIENT_PORT, 0, 1), // UDP destination port = DHCP client ?
BPF_STMT(BPF_RET + BPF_K, 65535), // return all
BPF_STMT(BPF_RET + BPF_K, 0) // ignore
};
static void dgram_handler (BDHCPClient *o, int event)
{
DebugObject_Access(&o->d_obj);
BLog(BLOG_ERROR, "packet socket error");
// report error
DEBUGERROR(&o->d_err, o->handler(o->user, BDHCPCLIENT_EVENT_ERROR));
return;
}
static void dhcp_handler (BDHCPClient *o, int event)
{
DebugObject_Access(&o->d_obj);
switch (event) {
case BDHCPCLIENTCORE_EVENT_UP:
ASSERT(!o->up)
o->up = 1;
o->handler(o->user, BDHCPCLIENT_EVENT_UP);
return;
case BDHCPCLIENTCORE_EVENT_DOWN:
ASSERT(o->up)
o->up = 0;
o->handler(o->user, BDHCPCLIENT_EVENT_DOWN);
return;
default:
ASSERT(0);
}
}
static void dhcp_func_getsendermac (BDHCPClient *o, uint8_t *out_mac)
{
DebugObject_Access(&o->d_obj);
BAddr remote_addr;
BIPAddr local_addr;
if (!BDatagram_GetLastReceiveAddrs(&o->dgram, &remote_addr, &local_addr)) {
BLog(BLOG_ERROR, "BDatagram_GetLastReceiveAddrs failed");
goto fail;
}
if (remote_addr.type != BADDR_TYPE_PACKET) {
BLog(BLOG_ERROR, "address type invalid");
goto fail;
}
if (remote_addr.packet.header_type != BADDR_PACKET_HEADER_TYPE_ETHERNET) {
BLog(BLOG_ERROR, "address header type invalid");
goto fail;
}
memcpy(out_mac, remote_addr.packet.phys_addr, 6);
return;
fail:
memset(out_mac, 0, 6);
}
int BDHCPClient_Init (BDHCPClient *o, const char *ifname, struct BDHCPClient_opts opts, BReactor *reactor, BRandom2 *random2, BDHCPClient_handler handler, void *user)
{
// init arguments
o->reactor = reactor;
o->handler = handler;
o->user = user;
// get interface information
uint8_t if_mac[6];
int if_mtu;
int if_index;
if (!badvpn_get_iface_info(ifname, if_mac, &if_mtu, &if_index)) {
BLog(BLOG_ERROR, "failed to get interface information");
goto fail0;
}
BLog(BLOG_INFO, "if_mac=%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8" if_mtu=%d if_index=%d",
if_mac[0], if_mac[1], if_mac[2], if_mac[3], if_mac[4], if_mac[5], if_mtu, if_index);
if (if_mtu < IPUDP_OVERHEAD) {
BLog(BLOG_ERROR, "MTU is too small for UDP/IP !?!");
goto fail0;
}
int dhcp_mtu = if_mtu - IPUDP_OVERHEAD;
// init dgram
if (!BDatagram_Init(&o->dgram, BADDR_TYPE_PACKET, o->reactor, o, (BDatagram_handler)dgram_handler)) {
BLog(BLOG_ERROR, "BDatagram_Init failed");
goto fail0;
}
// set socket filter
{
struct sock_filter filter[sizeof(dhcp_sock_filter) / sizeof(dhcp_sock_filter[0])];
memcpy(filter, dhcp_sock_filter, sizeof(filter));
struct sock_fprog fprog = {
.len = sizeof(filter) / sizeof(filter[0]),
.filter = filter
};
if (setsockopt(BDatagram_GetFd(&o->dgram), SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog)) < 0) {
BLog(BLOG_NOTICE, "not using socket filter");
}
}
// bind dgram
BAddr bind_addr;
BAddr_InitPacket(&bind_addr, hton16(ETHERTYPE_IPV4), if_index, BADDR_PACKET_HEADER_TYPE_ETHERNET, BADDR_PACKET_PACKET_TYPE_HOST, if_mac);
if (!BDatagram_Bind(&o->dgram, bind_addr)) {
BLog(BLOG_ERROR, "BDatagram_Bind failed");
goto fail1;
}
// set dgram send addresses
BAddr dest_addr;
uint8_t broadcast_mac[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
BAddr_InitPacket(&dest_addr, hton16(ETHERTYPE_IPV4), if_index, BADDR_PACKET_HEADER_TYPE_ETHERNET, BADDR_PACKET_PACKET_TYPE_BROADCAST, broadcast_mac);
BIPAddr local_addr;
BIPAddr_InitInvalid(&local_addr);
BDatagram_SetSendAddrs(&o->dgram, dest_addr, local_addr);
// init dgram interfaces
BDatagram_SendAsync_Init(&o->dgram, if_mtu);
BDatagram_RecvAsync_Init(&o->dgram, if_mtu);
// init sending
// init copier
PacketCopier_Init(&o->send_copier, dhcp_mtu, BReactor_PendingGroup(o->reactor));
// init encoder
DHCPIpUdpEncoder_Init(&o->send_encoder, PacketCopier_GetOutput(&o->send_copier), BReactor_PendingGroup(o->reactor));
// init buffer
if (!SinglePacketBuffer_Init(&o->send_buffer, DHCPIpUdpEncoder_GetOutput(&o->send_encoder), BDatagram_SendAsync_GetIf(&o->dgram), BReactor_PendingGroup(o->reactor))) {
BLog(BLOG_ERROR, "SinglePacketBuffer_Init failed");
goto fail2;
}
// init receiving
// init copier
PacketCopier_Init(&o->recv_copier, dhcp_mtu, BReactor_PendingGroup(o->reactor));
// init decoder
DHCPIpUdpDecoder_Init(&o->recv_decoder, PacketCopier_GetInput(&o->recv_copier), BReactor_PendingGroup(o->reactor));
// init buffer
if (!SinglePacketBuffer_Init(&o->recv_buffer, BDatagram_RecvAsync_GetIf(&o->dgram), DHCPIpUdpDecoder_GetInput(&o->recv_decoder), BReactor_PendingGroup(o->reactor))) {
BLog(BLOG_ERROR, "SinglePacketBuffer_Init failed");
goto fail3;
}
// init options
struct BDHCPClientCore_opts core_opts;
core_opts.hostname = opts.hostname;
core_opts.vendorclassid = opts.vendorclassid;
core_opts.clientid = opts.clientid;
core_opts.clientid_len = opts.clientid_len;
// auto-generate clientid from MAC if requested
uint8_t mac_cid[7];
if (opts.auto_clientid) {
mac_cid[0] = DHCP_HARDWARE_ADDRESS_TYPE_ETHERNET;
memcpy(mac_cid + 1, if_mac, 6);
core_opts.clientid = mac_cid;
core_opts.clientid_len = sizeof(mac_cid);
}
// init dhcp
if (!BDHCPClientCore_Init(&o->dhcp, PacketCopier_GetInput(&o->send_copier), PacketCopier_GetOutput(&o->recv_copier), if_mac, core_opts, o->reactor, random2, o,
(BDHCPClientCore_func_getsendermac)dhcp_func_getsendermac,
(BDHCPClientCore_handler)dhcp_handler
)) {
BLog(BLOG_ERROR, "BDHCPClientCore_Init failed");
goto fail4;
}
// set not up
o->up = 0;
DebugError_Init(&o->d_err, BReactor_PendingGroup(o->reactor));
DebugObject_Init(&o->d_obj);
return 1;
fail4:
SinglePacketBuffer_Free(&o->recv_buffer);
fail3:
DHCPIpUdpDecoder_Free(&o->recv_decoder);
PacketCopier_Free(&o->recv_copier);
SinglePacketBuffer_Free(&o->send_buffer);
fail2:
DHCPIpUdpEncoder_Free(&o->send_encoder);
PacketCopier_Free(&o->send_copier);
BDatagram_RecvAsync_Free(&o->dgram);
BDatagram_SendAsync_Free(&o->dgram);
fail1:
BDatagram_Free(&o->dgram);
fail0:
return 0;
}
void BDHCPClient_Free (BDHCPClient *o)
{
DebugObject_Free(&o->d_obj);
DebugError_Free(&o->d_err);
// free dhcp
BDHCPClientCore_Free(&o->dhcp);
// free receiving
SinglePacketBuffer_Free(&o->recv_buffer);
DHCPIpUdpDecoder_Free(&o->recv_decoder);
PacketCopier_Free(&o->recv_copier);
// free sending
SinglePacketBuffer_Free(&o->send_buffer);
DHCPIpUdpEncoder_Free(&o->send_encoder);
PacketCopier_Free(&o->send_copier);
// free dgram interfaces
BDatagram_RecvAsync_Free(&o->dgram);
BDatagram_SendAsync_Free(&o->dgram);
// free dgram
BDatagram_Free(&o->dgram);
}
int BDHCPClient_IsUp (BDHCPClient *o)
{
DebugObject_Access(&o->d_obj);
return o->up;
}
void BDHCPClient_GetClientIP (BDHCPClient *o, uint32_t *out_ip)
{
DebugObject_Access(&o->d_obj);
ASSERT(o->up)
BDHCPClientCore_GetClientIP(&o->dhcp, out_ip);
}
void BDHCPClient_GetClientMask (BDHCPClient *o, uint32_t *out_mask)
{
DebugObject_Access(&o->d_obj);
ASSERT(o->up)
BDHCPClientCore_GetClientMask(&o->dhcp, out_mask);
}
int BDHCPClient_GetRouter (BDHCPClient *o, uint32_t *out_router)
{
DebugObject_Access(&o->d_obj);
ASSERT(o->up)
return BDHCPClientCore_GetRouter(&o->dhcp, out_router);
}
int BDHCPClient_GetDNS (BDHCPClient *o, uint32_t *out_dns_servers, size_t max_dns_servers)
{
DebugObject_Access(&o->d_obj);
ASSERT(o->up)
return BDHCPClientCore_GetDNS(&o->dhcp, out_dns_servers, max_dns_servers);
}
void BDHCPClient_GetServerMAC (BDHCPClient *o, uint8_t *out_mac)
{
DebugObject_Access(&o->d_obj);
ASSERT(o->up)
BDHCPClientCore_GetServerMAC(&o->dhcp, out_mac);
}