int
ni_dhcp_build_message(const ni_dhcp_device_t *dev,
unsigned int msg_code,
const ni_addrconf_lease_t *lease,
ni_buffer_t *msgbuf)
{
const ni_dhcp_config_t *options = dev->config;
struct in_addr src_addr, dst_addr;
ni_dhcp_message_t *message = NULL;
if (!options || !lease)
return -1;
if (IN_LINKLOCAL(ntohl(lease->dhcp.address.s_addr))) {
ni_error("cannot request a link local address");
goto failed;
}
src_addr.s_addr = dst_addr.s_addr = 0;
switch (msg_code) {
case DHCP_DISCOVER:
if (lease->dhcp.serveraddress.s_addr != 0)
return -1;
break;
case DHCP_REQUEST:
case DHCP_RELEASE:
case DHCP_INFORM:
if (lease->dhcp.address.s_addr == 0 || lease->dhcp.serveraddress.s_addr == 0)
return -1;
src_addr = lease->dhcp.address;
dst_addr = lease->dhcp.serveraddress;
break;
}
/* Reserve some room for the IP and UDP header */
ni_buffer_reserve_head(msgbuf, sizeof(struct ip) + sizeof(struct udphdr));
/* Build the message */
message = ni_buffer_push_tail(msgbuf, sizeof(*message));
message->op = DHCP_BOOTREQUEST;
message->hwtype = dev->system.arp_type;
message->xid = dev->dhcp.xid;
message->cookie = htonl(MAGIC_COOKIE);
message->secs = htons(ni_dhcp_device_uptime(dev, 0xFFFF));
if (dev->fsm.state == NI_DHCP_STATE_BOUND
|| dev->fsm.state == NI_DHCP_STATE_RENEWING
|| dev->fsm.state == NI_DHCP_STATE_REBINDING)
message->ciaddr = lease->dhcp.address.s_addr;
switch (dev->system.arp_type) {
case ARPHRD_ETHER:
case ARPHRD_IEEE802:
if (dev->system.hwaddr.len > sizeof(message->chaddr)) {
ni_error("dhcp cannot handle hwaddress length %u",
dev->system.hwaddr.len);
goto failed;
}
message->hwlen = dev->system.hwaddr.len;
memcpy(&message->chaddr, dev->system.hwaddr.data, dev->system.hwaddr.len);
break;
case ARPHRD_IEEE1394:
case ARPHRD_INFINIBAND:
message->hwlen = 0;
if (message->ciaddr == 0)
message->flags = htons(BROADCAST_FLAG);
break;
default:
ni_error("dhcp: unknown hardware type %d", dev->system.arp_type);
}
ni_dhcp_option_put8(msgbuf, DHCP_MESSAGETYPE, msg_code);
if (msg_code == DHCP_REQUEST)
ni_dhcp_option_put16(msgbuf, DHCP_MAXMESSAGESIZE, dev->system.mtu);
ni_dhcp_option_put(msgbuf, DHCP_CLIENTID,
options->raw_client_id.data,
options->raw_client_id.len);
if (msg_code != DHCP_DECLINE && msg_code != DHCP_RELEASE) {
if (options->userclass.len > 0)
ni_dhcp_option_put(msgbuf, DHCP_USERCLASS,
options->userclass.data,
options->userclass.len);
if (options->classid && options->classid[0])
ni_dhcp_option_puts(msgbuf, DHCP_CLASSID, options->classid);
}
if (msg_code == DHCP_DISCOVER || msg_code == DHCP_REQUEST) {
if (lease->dhcp.address.s_addr)
ni_dhcp_option_put_ipv4(msgbuf, DHCP_ADDRESS, lease->dhcp.address);
if (lease->dhcp.lease_time != 0)
ni_dhcp_option_put32(msgbuf, DHCP_LEASETIME, lease->dhcp.lease_time);
}
if (msg_code == DHCP_REQUEST) {
if (lease->dhcp.serveraddress.s_addr)
ni_dhcp_option_put_ipv4(msgbuf, DHCP_SERVERIDENTIFIER, lease->dhcp.serveraddress);
}
if (msg_code == DHCP_DISCOVER || msg_code == DHCP_INFORM || msg_code == DHCP_REQUEST) {
unsigned int params_begin;
if (options->hostname && options->hostname[0]) {
if (options->fqdn == FQDN_DISABLE) {
ni_dhcp_option_puts(msgbuf, DHCP_HOSTNAME, options->hostname);
} else {
/* IETF DHC-FQDN option(81)
* http://tools.ietf.org/html/rfc4702#section-2.1
*
* Flags: 0000NEOS
* S: 1 => Client requests Server to update
* a RR in DNS as well as PTR
* O: 1 => Server indicates to client that
* DNS has been updated
* E: 1 => Name data is DNS format
* N: 1 => Client requests Server to not
* update DNS
*/
ni_buffer_putc(msgbuf, DHCP_FQDN);
ni_buffer_putc(msgbuf, strlen(options->hostname) + 3);
ni_buffer_putc(msgbuf, options->fqdn & 0x9);
ni_buffer_putc(msgbuf, 0); /* from server for PTR RR */
ni_buffer_putc(msgbuf, 0); /* from server for A RR if S=1 */
ni_buffer_put(msgbuf, options->hostname, strlen(options->hostname));
}
}
params_begin = ni_dhcp_option_begin(msgbuf, DHCP_PARAMETERREQUESTLIST);
if (msg_code == DHCP_DISCOVER) {
/* dhcpcd says we should include just a single option
* in discovery packets.
* I'm not convinced this is right, but let's do it
* this way.
*/
ni_buffer_putc(msgbuf, DHCP_DNSSERVER);
} else {
if (msg_code != DHCP_INFORM) {
ni_buffer_putc(msgbuf, DHCP_RENEWALTIME);
ni_buffer_putc(msgbuf, DHCP_REBINDTIME);
}
ni_buffer_putc(msgbuf, DHCP_NETMASK);
ni_buffer_putc(msgbuf, DHCP_BROADCAST);
if (options->flags & DHCP_DO_CSR)
ni_buffer_putc(msgbuf, DHCP_CSR);
if (options->flags & DHCP_DO_MSCSR)
ni_buffer_putc(msgbuf, DHCP_MSCSR);
/* RFC 3442 states classless static routes should be
* before routers and static routes as classless static
* routes override them both */
ni_buffer_putc(msgbuf, DHCP_STATICROUTE);
ni_buffer_putc(msgbuf, DHCP_ROUTERS);
ni_buffer_putc(msgbuf, DHCP_HOSTNAME);
ni_buffer_putc(msgbuf, DHCP_DNSSEARCH);
ni_buffer_putc(msgbuf, DHCP_DNSDOMAIN);
ni_buffer_putc(msgbuf, DHCP_DNSSERVER);
if (options->flags & DHCP_DO_NIS) {
ni_buffer_putc(msgbuf, DHCP_NISDOMAIN);
ni_buffer_putc(msgbuf, DHCP_NISSERVER);
}
if (options->flags & DHCP_DO_NTP)
ni_buffer_putc(msgbuf, DHCP_NTPSERVER);
ni_buffer_putc(msgbuf, DHCP_MTU);
ni_buffer_putc(msgbuf, DHCP_ROOTPATH);
ni_buffer_putc(msgbuf, DHCP_SIPSERVER);
ni_buffer_putc(msgbuf, DHCP_LPRSERVER);
ni_buffer_putc(msgbuf, DHCP_LOGSERVER);
ni_buffer_putc(msgbuf, DHCP_NETBIOSNAMESERVER);
ni_buffer_putc(msgbuf, DHCP_NETBIOSDDSERVER);
ni_buffer_putc(msgbuf, DHCP_NETBIOSNODETYPE);
ni_buffer_putc(msgbuf, DHCP_NETBIOSSCOPE);
}
ni_dhcp_option_end(msgbuf, params_begin);
}
ni_buffer_putc(msgbuf, DHCP_END);
#ifdef BOOTP_MESSAGE_LENGTH_MIN
ni_buffer_pad(msgbuf, BOOTP_MESSAGE_LENGTH_MIN, DHCP_PAD);
#endif
if (ni_capture_build_udp_header(msgbuf, src_addr, DHCP_CLIENT_PORT, dst_addr, DHCP_SERVER_PORT) < 0) {
ni_error("unable to build packet header");
goto failed;
}
return 0;
failed:
return -1;
}
int
ni_dhcp4_build_message(const ni_dhcp4_device_t *dev, unsigned int msg_code,
const ni_addrconf_lease_t *lease, ni_buffer_t *msgbuf)
{
const ni_dhcp4_config_t *options = dev->config;
struct in_addr src_addr, dst_addr;
int renew = dev->fsm.state == NI_DHCP4_STATE_RENEWING && msg_code == DHCP4_REQUEST;
if (!options || !lease) {
ni_error("%s: %s: %s: missing %s %s", __func__,
dev->ifname, ni_dhcp4_message_name(msg_code),
options? "" : "options", lease ? "" : "lease");
return -1;
}
if (IN_LINKLOCAL(ntohl(lease->dhcp4.address.s_addr))) {
ni_error("%s: cannot request a link local address", dev->ifname);
goto failed;
}
/* Reserve some room for the IP and UDP header */
if (!renew)
ni_buffer_reserve_head(msgbuf, sizeof(struct ip) + sizeof(struct udphdr));
src_addr.s_addr = dst_addr.s_addr = 0;
switch (msg_code) {
case DHCP4_INFORM:
if (__ni_dhcp4_build_msg_inform(dev, lease, msgbuf) < 0)
goto failed;
break;
case DHCP4_DISCOVER:
if (__ni_dhcp4_build_msg_discover(dev, lease, msgbuf) < 0)
goto failed;
break;
case DHCP4_DECLINE:
if (__ni_dhcp4_build_msg_decline(dev, lease, msgbuf) < 0)
goto failed;
break;
case DHCP4_RELEASE:
if (__ni_dhcp4_build_msg_release(dev, lease, msgbuf) < 0)
goto failed;
break;
case DHCP4_REQUEST:
switch (dev->fsm.state) {
case NI_DHCP4_STATE_REQUESTING:
src_addr.s_addr = 0;
dst_addr.s_addr = 0;
if (__ni_dhcp4_build_msg_request_offer(dev, lease, msgbuf) < 0)
goto failed;
break;
case NI_DHCP4_STATE_RENEWING:
src_addr = lease->dhcp4.address;
dst_addr = lease->dhcp4.server_id;
if (__ni_dhcp4_build_msg_request_renew(dev, lease, msgbuf) < 0)
goto failed;
break;
case NI_DHCP4_STATE_REBINDING:
src_addr = lease->dhcp4.address;
dst_addr.s_addr = 0;
if (__ni_dhcp4_build_msg_request_rebind(dev, lease, msgbuf) < 0)
goto failed;
break;
case NI_DHCP4_STATE_REBOOT:
src_addr.s_addr = 0;
dst_addr.s_addr = 0;
if (__ni_dhcp4_build_msg_request_reboot(dev, lease, msgbuf) < 0)
goto failed;
break;
default:
goto failed;
}
break;
default:
goto failed;
}
ni_buffer_putc(msgbuf, DHCP4_END);
#ifdef BOOTP_MESSAGE_LENGTH_MIN
ni_buffer_pad(msgbuf, BOOTP_MESSAGE_LENGTH_MIN, DHCP4_PAD);
#endif
if (!renew && ni_capture_build_udp_header(msgbuf, src_addr,
DHCP4_CLIENT_PORT, dst_addr, DHCP4_SERVER_PORT) < 0) {
ni_error("%s: unable to build packet header", dev->ifname);
goto failed;
}
return 0;
failed:
return -1;
}
