badvpn/dhcpclient/DHCPIpUdpEncoder.c

120 lines
4.2 KiB
C

/**
* @file DHCPIpUdpEncoder.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 <limits.h>
#include <string.h>
#include <stddef.h>
#include <misc/ipv4_proto.h>
#include <misc/udp_proto.h>
#include <misc/byteorder.h>
#include <dhcpclient/DHCPIpUdpEncoder.h>
#define DHCP_SERVER_PORT 67
#define DHCP_CLIENT_PORT 68
#define IPUDP_HEADER_SIZE (sizeof(struct ipv4_header) + sizeof(struct udp_header))
static void output_handler_recv (DHCPIpUdpEncoder *o, uint8_t *data)
{
DebugObject_Access(&o->d_obj);
// remember output packet
o->data = data;
// receive payload
PacketRecvInterface_Receiver_Recv(o->input, o->data + IPUDP_HEADER_SIZE);
}
static void input_handler_done (DHCPIpUdpEncoder *o, int data_len)
{
DebugObject_Access(&o->d_obj);
// build IP header
struct ipv4_header iph;
iph.version4_ihl4 = IPV4_MAKE_VERSION_IHL(sizeof(iph));
iph.ds = hton8(0);
iph.total_length = hton16(IPUDP_HEADER_SIZE + data_len);
iph.identification = hton16(0);
iph.flags3_fragmentoffset13 = hton16(0);
iph.ttl = hton8(64);
iph.protocol = hton8(IPV4_PROTOCOL_UDP);
iph.checksum = hton16(0);
iph.source_address = hton32(0x00000000);
iph.destination_address = hton32(0xFFFFFFFF);
iph.checksum = ipv4_checksum(&iph, NULL, 0);
// write UDP header
struct udp_header udph;
udph.source_port = hton16(DHCP_CLIENT_PORT);
udph.dest_port = hton16(DHCP_SERVER_PORT);
udph.length = hton16(sizeof(udph) + data_len);
udph.checksum = hton16(0);
udph.checksum = udp_checksum(&udph, o->data + IPUDP_HEADER_SIZE, data_len, iph.source_address, iph.destination_address);
// write header
memcpy(o->data, &iph, sizeof(iph));
memcpy(o->data + sizeof(iph), &udph, sizeof(udph));
// finish packet
PacketRecvInterface_Done(&o->output, IPUDP_HEADER_SIZE + data_len);
}
void DHCPIpUdpEncoder_Init (DHCPIpUdpEncoder *o, PacketRecvInterface *input, BPendingGroup *pg)
{
ASSERT(PacketRecvInterface_GetMTU(input) <= INT_MAX - IPUDP_HEADER_SIZE)
// init arguments
o->input = input;
// init input
PacketRecvInterface_Receiver_Init(o->input, (PacketRecvInterface_handler_done)input_handler_done, o);
// init output
PacketRecvInterface_Init(&o->output, IPUDP_HEADER_SIZE + PacketRecvInterface_GetMTU(o->input), (PacketRecvInterface_handler_recv)output_handler_recv, o, pg);
DebugObject_Init(&o->d_obj);
}
void DHCPIpUdpEncoder_Free (DHCPIpUdpEncoder *o)
{
DebugObject_Free(&o->d_obj);
// free output
PacketRecvInterface_Free(&o->output);
}
PacketRecvInterface * DHCPIpUdpEncoder_GetOutput (DHCPIpUdpEncoder *o)
{
DebugObject_Access(&o->d_obj);
return &o->output;
}