ndhc/dhcp.h
Nicholas J. Kain 8db8c5589d Replace CMake with GNU Make.
There was previously support for both build systems, but ndhc is
undemanding and there is no point in maintaining a complex
CMake build.
2022-01-22 18:39:41 -05:00

103 lines
3.8 KiB
C

/* dhcp.h - general DHCP protocol handling
*
* Copyright 2004-2018 Nicholas J. Kain <njkain at gmail dot com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - 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.
*
* 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 COPYRIGHT HOLDER OR CONTRIBUTORS 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.
*/
#ifndef NDHC_DHCP_H_
#define NDHC_DHCP_H_
#include <stdint.h>
#include <netinet/udp.h>
#include <netinet/ip.h>
#include "ndhc.h"
#define DHCP_SERVER_PORT 67
#define DHCP_CLIENT_PORT 68
#define DHCP_MAGIC 0x63825363
enum {
DHCPDISCOVER = 1,
DHCPOFFER = 2,
DHCPREQUEST = 3,
DHCPDECLINE = 4,
DHCPACK = 5,
DHCPNAK = 6,
DHCPRELEASE = 7,
DHCPINFORM = 8
};
struct dhcpmsg {
uint8_t op; // Message type: 1 = BOOTREQUEST for clients.
uint8_t htype; // ARP HW address type: always '1' for ethernet.
uint8_t hlen; // Hardware address length: always '6' for ethernet.
uint8_t hops; // Client sets to zero.
uint32_t xid; // Transaction ID: random number identifying session
uint16_t secs; // Filled by client: seconds since client began address
// aquisition or renewal process.
uint16_t flags; // DHCP flags
uint32_t ciaddr; // Client IP: only filled in if client is in BOUND, RENEW,
// or REBINDING and can reply to ARP requests
uint32_t yiaddr; // 'your' (client) IP address
uint32_t siaddr; // Always zero -- unused.
uint32_t giaddr; // Always zero -- unused.
uint8_t chaddr[16]; // Client MAC address
uint8_t sname[64]; // More DHCP options (#3)
uint8_t file[128]; // More DHCP options (#2)
uint32_t cookie; // Magic number cookie that starts DHCP options
uint8_t options[308]; // DHCP options field (#1)
};
struct ip_udp_dhcp_packet {
struct iphdr ip;
struct udphdr udp;
struct dhcpmsg data;
};
struct udp_dhcp_packet {
struct udphdr udp;
struct dhcpmsg data;
};
void start_dhcp_listen(struct client_state_t *cs);
void stop_dhcp_listen(struct client_state_t *cs);
bool dhcp_packet_get(struct client_state_t *cs, struct dhcpmsg *packet,
uint8_t *msgtype, uint32_t *srcaddr);
ssize_t send_discover(struct client_state_t *cs);
ssize_t send_selecting(struct client_state_t *cs);
ssize_t send_renew_or_rebind(struct client_state_t *cs, bool is_renew);
static inline ssize_t send_renew(struct client_state_t *cs)
{
return send_renew_or_rebind(cs, true);
}
static inline ssize_t send_rebind(struct client_state_t *cs)
{
return send_renew_or_rebind(cs, false);
}
ssize_t send_decline(struct client_state_t *cs, uint32_t server);
ssize_t send_release(struct client_state_t *cs);
#endif