blob: 8ca2614072b16af2010cdfcf9d832bb5196926a2 [file] [log] [blame]
/*
* DHCP RFC 2131 and 2132
*/
#include <sys/types.h>
#include <sys/uio.h>
#include <netinet/in.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include "ipconfig.h"
#include "netdev.h"
#include "bootp_packet.h"
#include "bootp_proto.h"
#include "dhcp_proto.h"
#include "packet.h"
static uint8_t dhcp_params[] = {
1, /* subnet mask */
3, /* default gateway */
6, /* DNS server */
12, /* host name */
15, /* domain name */
17, /* root path */
26, /* interface mtu */
28, /* broadcast addr */
40, /* NIS domain name (why?) */
};
static uint8_t dhcp_discover_hdr[] = {
99, 130, 83, 99, /* bootp cookie */
53, 1, DHCPDISCOVER, /* dhcp message type */
55, sizeof(dhcp_params), /* parameter list */
};
static uint8_t dhcp_request_hdr[] = {
99, 130, 83, 99, /* boot cookie */
53, 1, DHCPREQUEST, /* dhcp message type */
#define SERVER_IP_OFF 9
54, 4, 0, 0, 0, 0, /* server IP */
#define REQ_IP_OFF 15
50, 4, 0, 0, 0, 0, /* requested IP address */
55, sizeof(dhcp_params), /* parameter list */
};
static uint8_t dhcp_end[] = {
255,
};
/* Both iovecs below have to have the same structure, since dhcp_send()
pokes at the internals */
#define DHCP_IOV_LEN 7
static struct iovec dhcp_discover_iov[DHCP_IOV_LEN] = {
/* [0] = ip + udp header */
/* [1] = bootp header */
[2] = {dhcp_discover_hdr, sizeof(dhcp_discover_hdr)},
[3] = {dhcp_params, sizeof(dhcp_params)},
/* [4] = optional vendor class */
/* [5] = optional hostname */
/* [6] = {dhcp_end, sizeof(dhcp_end)} */
};
static struct iovec dhcp_request_iov[DHCP_IOV_LEN] = {
/* [0] = ip + udp header */
/* [1] = bootp header */
[2] = {dhcp_request_hdr, sizeof(dhcp_request_hdr)},
[3] = {dhcp_params, sizeof(dhcp_params)},
/* [4] = optional vendor class */
/* [5] = optional hostname */
/* [6] = {dhcp_end, sizeof(dhcp_end)} */
};
/*
* Parse a DHCP response packet
* Returns:
* 0 = Unexpected packet, not parsed
* 2 = DHCPOFFER (from dhcp_proto.h)
* 5 = DHCPACK
* 6 = DHCPNACK
*/
static int dhcp_parse(struct netdev *dev, struct bootp_hdr *hdr,
uint8_t *exts, int extlen)
{
uint8_t type = 0;
uint32_t serverid = INADDR_NONE;
uint32_t leasetime = 0;
int ret = 0;
if (extlen >= 4 && exts[0] == 99 && exts[1] == 130 &&
exts[2] == 83 && exts[3] == 99) {
uint8_t *ext;
for (ext = exts + 4; ext - exts < extlen;) {
int len;
uint8_t opt = *ext++;
if (opt == 0)
continue;
else if (opt == 255)
break;
if (ext - exts >= extlen)
break;
len = *ext++;
if (ext - exts + len > extlen)
break;
switch (opt) {
case 51: /* IP Address Lease Time */
if (len == 4)
leasetime = ntohl(*(uint32_t *)ext);
break;
case 53: /* DHCP Message Type */
if (len == 1)
type = *ext;
break;
case 54: /* Server Identifier */
if (len == 4)
memcpy(&serverid, ext, 4);
break;
}
ext += len;
}
}
switch (type) {
case DHCPOFFER:
ret = bootp_parse(dev, hdr, exts, extlen) ? DHCPOFFER : 0;
if (ret == DHCPOFFER && serverid != INADDR_NONE)
dev->serverid = serverid;
dprintf("\n dhcp offer\n");
break;
case DHCPACK:
dev->dhcpleasetime = leasetime;
ret = bootp_parse(dev, hdr, exts, extlen) ? DHCPACK : 0;
dprintf("\n dhcp ack\n");
break;
case DHCPNAK:
ret = DHCPNAK;
dprintf("\n dhcp nak\n");
break;
}
return ret;
}
/*
* Receive and parse a DHCP packet
* Returns:
*-1 = Error in packet_recv, try again later
* 0 = Unexpected packet, discarded
* 2 = DHCPOFFER (from dhcp_proto.h)
* 5 = DHCPACK
* 6 = DHCPNACK
*/
static int dhcp_recv(struct netdev *dev)
{
struct bootp_hdr bootp;
uint8_t dhcp_options[1500];
struct iovec iov[] = {
/* [0] = ip + udp header */
[1] = {&bootp, sizeof(struct bootp_hdr)},
[2] = {dhcp_options, sizeof(dhcp_options)}
};
int ret;
ret = packet_recv(dev, iov, 3);
if (ret <= 0)
return ret;
dprintf("\n dhcp xid %08x ", dev->bootp.xid);
if (ret < sizeof(struct bootp_hdr) || bootp.op != BOOTP_REPLY ||
/* RFC951 7.5 */ bootp.xid != dev->bootp.xid ||
memcmp(bootp.chaddr, dev->hwaddr, 16))
return 0;
ret -= sizeof(struct bootp_hdr);
return dhcp_parse(dev, &bootp, dhcp_options, ret);
}
static int dhcp_send(struct netdev *dev, struct iovec *vec)
{
struct bootp_hdr bootp;
char dhcp_hostname[SYS_NMLN+2];
int i = 4;
memset(&bootp, 0, sizeof(struct bootp_hdr));
bootp.op = BOOTP_REQUEST;
bootp.htype = dev->hwtype;
bootp.hlen = dev->hwlen;
bootp.xid = dev->bootp.xid;
bootp.ciaddr = INADDR_ANY;
bootp.yiaddr = dev->ip_addr;
bootp.giaddr = INADDR_ANY;
bootp.secs = htons(time(NULL) - dev->open_time);
memcpy(bootp.chaddr, dev->hwaddr, 16);
vec[1].iov_base = &bootp;
vec[1].iov_len = sizeof(struct bootp_hdr);
dprintf("xid %08x secs %d ", bootp.xid, ntohs(bootp.secs));
if (vendor_class_identifier_len > 2) {
vec[i].iov_base = vendor_class_identifier;
vec[i].iov_len = vendor_class_identifier_len;
i++;
dprintf("vendor_class_identifier \"%.*s\" ",
vendor_class_identifier_len-2,
vendor_class_identifier+2);
}
if (dev->reqhostname[0] != '\0') {
int len = strlen(dev->reqhostname);
dhcp_hostname[0] = 12;
dhcp_hostname[1] = len;
memcpy(dhcp_hostname+2, dev->reqhostname, len);
vec[i].iov_base = dhcp_hostname;
vec[i].iov_len = len+2;
i++;
printf("hostname %.*s ", len, dhcp_hostname+2);
}
vec[i].iov_base = dhcp_end;
vec[i].iov_len = sizeof(dhcp_end);
return packet_send(dev, vec, i + 1);
}
/*
* Send a DHCP discover packet
*/
int dhcp_send_discover(struct netdev *dev)
{
dev->ip_addr = INADDR_ANY;
dev->ip_gateway = INADDR_ANY;
dprintf("-> dhcp discover ");
return dhcp_send(dev, dhcp_discover_iov);
}
/*
* Receive a DHCP offer packet
*/
int dhcp_recv_offer(struct netdev *dev)
{
return dhcp_recv(dev);
}
/*
* Send a DHCP request packet
*/
int dhcp_send_request(struct netdev *dev)
{
memcpy(&dhcp_request_hdr[SERVER_IP_OFF], &dev->serverid, 4);
memcpy(&dhcp_request_hdr[REQ_IP_OFF], &dev->ip_addr, 4);
dprintf("-> dhcp request ");
return dhcp_send(dev, dhcp_request_iov);
}
/*
* Receive a DHCP ack packet
*/
int dhcp_recv_ack(struct netdev *dev)
{
return dhcp_recv(dev);
}