// decline a
static err_t dhcp_decline(struct dhcp_state *state)
{
err_t result = ERR_OK;
u16_t msecs;
DEBUGF(DHCP_DEBUG, ("dhcp_decline()\n"));
dhcp_set_state(state, DHCP_BACKING_OFF);
// create and initialize the DHCP message header
result = dhcp_create_request(state);
if (result == ERR_OK)
{
dhcp_option(state, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
dhcp_option_byte(state, DHCP_DECLINE);
dhcp_option(state, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
dhcp_option_short(state, 576);
dhcp_option_trailer(state);
// resize pbuf to reflect true size of options
pbuf_realloc(state->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + state->options_out_len);
udp_bind(state->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
udp_connect(state->pcb, &state->server_ip_addr, DHCP_SERVER_PORT);
udp_send(state->pcb, state->p_out);
dhcp_delete_request(state);
}
state->tries++;
msecs = 10*1000;
state->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
DEBUGF(DHCP_DEBUG, ("dhcp_decline(): request timeout %u msecs\n", msecs));
return result;
}
void dhcp_inform(struct netif *netif)
{
struct dhcp_state *state = NULL;
err_t result = ERR_OK;
state = mem_malloc(sizeof(struct dhcp_state));
if (state == NULL)
{
DEBUGF(DHCP_DEBUG, ("dhcp_inform(): could not allocate dhcp_state\n"));
return;
}
memset(state, 0, sizeof(struct dhcp_state));
DEBUGF(DHCP_DEBUG, ("dhcp_inform(): allocated dhcp_state\n"));
state->pcb = udp_new();
if (state->pcb == NULL) {
DEBUGF(DHCP_DEBUG, ("dhcp_inform(): could not obtain pcb\n"));
mem_free((void *)state);
return;
}
DEBUGF(DHCP_DEBUG, ("dhcp_inform(): created new udp pcb\n"));
state->netif = netif;
// we are last in list
state->next = NULL;
// create and initialize the DHCP message header
result = dhcp_create_request(state);
if (result == ERR_OK)
{
dhcp_option(state, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
dhcp_option_byte(state, DHCP_INFORM);
dhcp_option(state, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
dhcp_option_short(state, 576);
dhcp_option_trailer(state);
pbuf_realloc(state->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + state->options_out_len);
udp_bind(state->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
udp_connect(state->pcb, IP_ADDR_BROADCAST, DHCP_SERVER_PORT);
udp_send(state->pcb, state->p_out);
udp_connect(state->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
dhcp_delete_request(state);
}
if (state != NULL)
{
if (state->pcb != NULL) udp_remove(state->pcb);
state->pcb = NULL;
mem_free((void *)state);
}
}
/**
* Start the DHCP process, discover a server
*
*/
static err_t dhcp_discover(struct dhcp_state *state)
{
err_t result = ERR_OK;
u16_t msecs;
DEBUGF(DHCP_DEBUG, ("dhcp_discover(%p)\n", state));
ip_addr_set(&state->offered_ip_addr, IP_ADDR_ANY);
// create and initialize the DHCP message header
DEBUGF(DHCP_DEBUG, ("set ip addr, creating request()\n"));
result = dhcp_create_request(state);
DEBUGF(DHCP_DEBUG, ("created request\n"));
if (result == ERR_OK)
{
dhcp_option(state, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
dhcp_option_byte(state, DHCP_DISCOVER);
dhcp_option(state, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
dhcp_option_short(state, 576);
dhcp_option(state, DHCP_OPTION_PARAMETER_REQUEST_LIST, 3);
dhcp_option_byte(state, DHCP_OPTION_SUBNET_MASK);
dhcp_option_byte(state, DHCP_OPTION_ROUTER);
dhcp_option_byte(state, DHCP_OPTION_BROADCAST);
dhcp_option_trailer(state);
pbuf_realloc(state->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + state->options_out_len);
DEBUGF(DHCP_DEBUG, ("about to do udp recv\n"));
udp_recv(state->pcb, dhcp_recv, state);
DEBUGF(DHCP_DEBUG, ("about to do udp bind\n"));
udp_bind(state->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
DEBUGF(DHCP_DEBUG, ("about to do udp connect\n"));
udp_connect(state->pcb, IP_ADDR_BROADCAST, DHCP_SERVER_PORT);
DEBUGF(DHCP_DEBUG, ("about to do udp send\n"));
udp_send(state->pcb, state->p_out);
udp_bind(state->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
udp_connect(state->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
dhcp_delete_request(state);
}
state->tries++;
msecs = state->tries < 4 ? (state->tries + 1) * 1000 : 10 * 1000;
state->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
DEBUGF(DHCP_DEBUG, ("dhcp_discover(): request timeout %u msecs\n", msecs));
dhcp_set_state(state, DHCP_SELECTING);
return result;
}
static err_t dhcp_release(struct dhcp_state *state)
{
err_t result;
u16_t msecs;
DEBUGF(DHCP_DEBUG, ("dhcp_release()\n"));
// and idle DHCP client
dhcp_set_state(state, DHCP_OFF);
// create and initialize the DHCP message header
result = dhcp_create_request(state);
if (result == ERR_OK)
{
dhcp_option(state, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
dhcp_option_byte(state, DHCP_RELEASE);
dhcp_option_trailer(state);
pbuf_realloc(state->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + state->options_out_len);
udp_bind(state->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
udp_connect(state->pcb, &state->server_ip_addr, DHCP_SERVER_PORT);
udp_send(state->pcb, state->p_out);
dhcp_delete_request(state);
}
state->tries++;
msecs = state->tries < 10 ? state->tries * 1000 : 10 * 1000;
state->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
DEBUGF(DHCP_DEBUG, ("dhcp_release(): request timeout %u msecs\n", msecs));
// remove IP address from interface
netif_set_ipaddr(state->netif, IP_ADDR_ANY);
netif_set_gw(state->netif, IP_ADDR_ANY);
netif_set_netmask(state->netif, IP_ADDR_ANY);
return result;
}
/**
* Select a DHCP server offer out of all offers.
*
* Simply select the first offer received, ignore others
*/
static err_t dhcp_select(struct dhcp_state *state)
{
err_t result;
u32_t msecs;
DEBUGF(DHCP_DEBUG, ("dhcp_select()\n"));
// create and initialize the DHCP message header
result = dhcp_create_request(state);
if (result == ERR_OK)
{
dhcp_option(state, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
dhcp_option_byte(state, DHCP_REQUEST);
dhcp_option(state, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
dhcp_option_short(state, 576);
/* MUST request the offered IP address */
dhcp_option(state, DHCP_OPTION_REQUESTED_IP, 4);
dhcp_option_long(state, ntohl(state->offered_ip_addr.addr));
dhcp_option(state, DHCP_OPTION_SERVER_ID, 4);
dhcp_option_long(state, ntohl(state->server_ip_addr.addr));
dhcp_option(state, DHCP_OPTION_PARAMETER_REQUEST_LIST, 3);
dhcp_option_byte(state, DHCP_OPTION_SUBNET_MASK);
dhcp_option_byte(state, DHCP_OPTION_ROUTER);
dhcp_option_byte(state, DHCP_OPTION_BROADCAST);
dhcp_option_trailer(state);
pbuf_realloc(state->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + state->options_out_len);
udp_bind(state->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
udp_connect(state->pcb, IP_ADDR_BROADCAST, DHCP_SERVER_PORT);
udp_send(state->pcb, state->p_out);
// reconnect to any (or to server here?!)
udp_connect(state->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
dhcp_delete_request(state);
}
state->tries++;
msecs = state->tries < 4 ? state->tries * 1000 : 4 * 1000;
state->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
DEBUGF(DHCP_DEBUG, ("dhcp_select(): request timeout %u msecs\n", msecs));
dhcp_set_state(state, DHCP_REQUESTING);
return result;
}
/**
* Find DHCP option within DHCP options block, and its encapsulator (if any)
*
* @v options DHCP options block
* @v tag DHCP option tag to search for
* @ret encap_offset Offset of encapsulating DHCP option
* @ret offset Offset of DHCP option, or negative error
*
* Searches for the DHCP option matching the specified tag within the
* DHCP option block. Encapsulated options may be searched for by
* using DHCP_ENCAP_OPT() to construct the tag value.
*
* If the option is encapsulated, and @c encap_offset is non-NULL, it
* will be filled in with the offset of the encapsulating option.
*
* This routine is designed to be paranoid. It does not assume that
* the option data is well-formatted, and so must guard against flaws
* such as options missing a @c DHCP_END terminator, or options whose
* length would take them beyond the end of the data block.
*/
static int find_dhcp_option_with_encap ( struct dhcp_options *options,
unsigned int tag,
int *encap_offset ) {
unsigned int original_tag __attribute__ (( unused )) = tag;
struct dhcp_option *option;
int offset = 0;
ssize_t remaining = options->used_len;
unsigned int option_len;
/* Sanity check */
if ( tag == DHCP_PAD )
return -ENOENT;
/* Search for option */
while ( remaining ) {
/* Calculate length of this option. Abort processing
* if the length is malformed (i.e. takes us beyond
* the end of the data block).
*/
option = dhcp_option ( options, offset );
option_len = dhcp_option_len ( option );
remaining -= option_len;
if ( remaining < 0 )
break;
/* Check for explicit end marker */
if ( option->tag == DHCP_END ) {
if ( tag == DHCP_END )
/* Special case where the caller is interested
* in whether we have this marker or not.
*/
return offset;
else
break;
}
/* Check for matching tag */
if ( option->tag == tag ) {
DBGC ( options, "DHCPOPT %p found %s (length %d)\n",
options, dhcp_tag_name ( original_tag ),
option_len );
return offset;
}
/* Check for start of matching encapsulation block */
if ( DHCP_IS_ENCAP_OPT ( tag ) &&
( option->tag == DHCP_ENCAPSULATOR ( tag ) ) ) {
if ( encap_offset )
*encap_offset = offset;
/* Continue search within encapsulated option block */
tag = DHCP_ENCAPSULATED ( tag );
remaining = option_len;
offset += DHCP_OPTION_HEADER_LEN;
continue;
}
offset += option_len;
}
return -ENOENT;
}
err_t dhcp_renew(struct dhcp_state *state)
{
err_t result;
u16_t msecs;
DEBUGF(DHCP_DEBUG, ("dhcp_renew()\n"));
dhcp_set_state(state, DHCP_RENEWING);
// create and initialize the DHCP message header
result = dhcp_create_request(state);
if (result == ERR_OK)
{
dhcp_option(state, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
dhcp_option_byte(state, DHCP_REQUEST);
dhcp_option(state, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
dhcp_option_short(state, 576);
#if 0
dhcp_option(state, DHCP_OPTION_REQUESTED_IP, 4);
dhcp_option_long(state, ntohl(state->offered_ip_addr.addr));
#endif
#if 0
dhcp_option(state, DHCP_OPTION_SERVER_ID, 4);
dhcp_option_long(state, ntohl(state->server_ip_addr.addr));
#endif
dhcp_option_trailer(state);
pbuf_realloc(state->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + state->options_out_len);
udp_bind(state->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
udp_connect(state->pcb, &state->server_ip_addr, DHCP_SERVER_PORT);
udp_send(state->pcb, state->p_out);
dhcp_delete_request(state);
}
state->tries++;
// back-off on retries, but to a maximum of 20 seconds
msecs = state->tries < 10 ? state->tries * 2000 : 20 * 1000;
state->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
DEBUGF(DHCP_DEBUG, ("dhcp_renew(): request timeout %u msecs\n", msecs));
return result;
}
/**
* Fetch value of DHCP option setting
*
* @v options DHCP option block
* @v tag Setting tag number
* @v data Buffer to fill with setting data
* @v len Length of buffer
* @ret len Length of setting data, or negative error
*/
int dhcpopt_fetch ( struct dhcp_options *options, unsigned int tag,
void *data, size_t len ) {
int offset;
struct dhcp_option *option;
size_t option_len;
offset = find_dhcp_option_with_encap ( options, tag, NULL );
if ( offset < 0 )
return offset;
option = dhcp_option ( options, offset );
option_len = option->len;
if ( len > option_len )
len = option_len;
memcpy ( data, option->data, len );
return option_len;
}
/**
* Recalculate length of DHCP options block
*
* @v options Uninitialised DHCP option block
*
* The "used length" field will be updated based on scanning through
* the block to find the end of the options.
*/
void dhcpopt_update_used_len ( struct dhcp_options *options ) {
struct dhcp_option *option;
int offset = 0;
ssize_t remaining = options->alloc_len;
unsigned int option_len;
/* Find last non-pad option */
options->used_len = 0;
while ( remaining ) {
option = dhcp_option ( options, offset );
option_len = dhcp_option_len ( option );
remaining -= option_len;
if ( remaining < 0 )
break;
offset += option_len;
if ( option->tag != DHCP_PAD )
options->used_len = offset;
}
}
/**
* Set value of DHCP option
*
* @v options DHCP option block
* @v tag DHCP option tag
* @v data New value for DHCP option
* @v len Length of value, in bytes
* @ret offset Offset of DHCP option, or negative error
*
* Sets the value of a DHCP option within the options block. The
* option may or may not already exist. Encapsulators will be created
* (and deleted) as necessary.
*
* This call may fail due to insufficient space in the options block.
* If it does fail, and the option existed previously, the option will
* be left with its original value.
*/
static int set_dhcp_option ( struct dhcp_options *options, unsigned int tag,
const void *data, size_t len ) {
static const uint8_t empty_encap[] = { DHCP_END };
int offset;
int encap_offset = -1;
int creation_offset;
struct dhcp_option *option;
unsigned int encap_tag = DHCP_ENCAPSULATOR ( tag );
size_t old_len = 0;
size_t new_len = ( len ? ( len + DHCP_OPTION_HEADER_LEN ) : 0 );
int rc;
/* Sanity check */
if ( tag == DHCP_PAD )
return -ENOTTY;
creation_offset = find_dhcp_option_with_encap ( options, DHCP_END,
NULL );
if ( creation_offset < 0 )
creation_offset = options->used_len;
/* Find old instance of this option, if any */
offset = find_dhcp_option_with_encap ( options, tag, &encap_offset );
if ( offset >= 0 ) {
old_len = dhcp_option_len ( dhcp_option ( options, offset ) );
DBGC ( options, "DHCPOPT %p resizing %s from %zd to %zd\n",
options, dhcp_tag_name ( tag ), old_len, new_len );
} else {
DBGC ( options, "DHCPOPT %p creating %s (length %zd)\n",
options, dhcp_tag_name ( tag ), new_len );
}
/* Ensure that encapsulator exists, if required */
if ( encap_tag ) {
if ( encap_offset < 0 ) {
encap_offset =
set_dhcp_option ( options, encap_tag,
empty_encap,
sizeof ( empty_encap ) );
}
if ( encap_offset < 0 )
return encap_offset;
creation_offset = ( encap_offset + DHCP_OPTION_HEADER_LEN );
}
/* Create new option if necessary */
if ( offset < 0 )
offset = creation_offset;
/* Resize option to fit new data */
if ( ( rc = resize_dhcp_option ( options, offset, encap_offset,
old_len, new_len ) ) != 0 )
return rc;
/* Copy new data into option, if applicable */
if ( len ) {
option = dhcp_option ( options, offset );
option->tag = tag;
option->len = len;
memcpy ( &option->data, data, len );
}
/* Delete encapsulator if there's nothing else left in it */
if ( encap_offset >= 0 ) {
option = dhcp_option ( options, encap_offset );
if ( option->len <= 1 )
set_dhcp_option ( options, encap_tag, NULL, 0 );
}
return offset;
}
/**
* Resize a DHCP option
*
* @v options DHCP option block
* @v offset Offset of option to resize
* @v encap_offset Offset of encapsulating offset (or -ve for none)
* @v old_len Old length (including header)
* @v new_len New length (including header)
* @ret rc Return status code
*/
static int resize_dhcp_option ( struct dhcp_options *options,
int offset, int encap_offset,
size_t old_len, size_t new_len ) {
struct dhcp_option *encapsulator;
struct dhcp_option *option;
ssize_t delta = ( new_len - old_len );
size_t old_alloc_len;
size_t new_used_len;
size_t new_encapsulator_len;
void *source;
void *dest;
int rc;
/* Check for sufficient space */
if ( new_len > DHCP_MAX_LEN ) {
DBGC ( options, "DHCPOPT %p overlength option\n", options );
return -ENOSPC;
}
new_used_len = ( options->used_len + delta );
/* Expand options block, if necessary */
if ( new_used_len > options->alloc_len ) {
/* Reallocate options block */
old_alloc_len = options->alloc_len;
if ( ( rc = options->realloc ( options, new_used_len ) ) != 0 ) {
DBGC ( options, "DHCPOPT %p could not reallocate to "
"%zd bytes\n", options, new_used_len );
return rc;
}
/* Clear newly allocated space */
memset ( ( options->data + old_alloc_len ), 0,
( options->alloc_len - old_alloc_len ) );
}
/* Update encapsulator, if applicable */
if ( encap_offset >= 0 ) {
encapsulator = dhcp_option ( options, encap_offset );
new_encapsulator_len = ( encapsulator->len + delta );
if ( new_encapsulator_len > DHCP_MAX_LEN ) {
DBGC ( options, "DHCPOPT %p overlength encapsulator\n",
options );
return -ENOSPC;
}
encapsulator->len = new_encapsulator_len;
}
/* Update used length */
options->used_len = new_used_len;
/* Move remainder of option data */
option = dhcp_option ( options, offset );
source = ( ( ( void * ) option ) + old_len );
dest = ( ( ( void * ) option ) + new_len );
memmove ( dest, source, ( new_used_len - offset - new_len ) );
/* Shrink options block, if applicable */
if ( new_used_len < options->alloc_len ) {
if ( ( rc = options->realloc ( options, new_used_len ) ) != 0 ) {
DBGC ( options, "DHCPOPT %p could not reallocate to "
"%zd bytes\n", options, new_used_len );
return rc;
}
}
return 0;
}
