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-rw-r--r--src/include/gpxe/dhcp.h16
-rw-r--r--src/net/udp/dhcp.c197
2 files changed, 170 insertions, 43 deletions
diff --git a/src/include/gpxe/dhcp.h b/src/include/gpxe/dhcp.h
index 6825e406a..1dbb290ef 100644
--- a/src/include/gpxe/dhcp.h
+++ b/src/include/gpxe/dhcp.h
@@ -12,6 +12,7 @@
#include <gpxe/in.h>
#include <gpxe/udp.h>
#include <gpxe/async.h>
+#include <gpxe/retry.h>
/** BOOTP/DHCP server port */
#define BOOTPS_PORT 67
@@ -407,6 +408,14 @@ struct dhcp_session {
/** UDP connection for this session */
struct udp_connection udp;
+ /** Network device being configured */
+ struct net_device *netdev;
+
+ /** Options obtained from server */
+ struct dhcp_option_block *options;
+
+ /** Transaction ID, in network-endian order */
+ uint32_t xid;
/** State of the session
*
* This is a value for the @c DHCP_MESSAGE_TYPE option
@@ -415,11 +424,8 @@ struct dhcp_session {
int state;
/** Asynchronous operation for this DHCP session */
struct async_operation aop;
-
- /** Network device being configured */
- struct net_device *netdev;
- /** Transaction ID, in network-endian order */
- uint32_t xid;
+ /** Retransmission timer */
+ struct retry_timer timer;
};
extern unsigned long dhcp_num_option ( struct dhcp_option *option );
diff --git a/src/net/udp/dhcp.c b/src/net/udp/dhcp.c
index 276b5e1f5..3a1951cff 100644
--- a/src/net/udp/dhcp.c
+++ b/src/net/udp/dhcp.c
@@ -109,7 +109,7 @@ static int set_dhcp_packet_option ( struct dhcp_packet *dhcppkt,
unsigned int tag, const void *data,
size_t len ) {
struct dhcphdr *dhcphdr = dhcppkt->dhcphdr;
- struct dhcp_option_block *options;
+ struct dhcp_option_block *options = dhcppkt->options;
struct dhcp_option *option = NULL;
/* Special-case the magic options */
@@ -123,14 +123,22 @@ static int set_dhcp_packet_option ( struct dhcp_packet *dhcppkt,
case DHCP_EB_SIADDR:
memcpy ( &dhcphdr->siaddr, data, sizeof ( dhcphdr->siaddr ) );
return 0;
+ case DHCP_MESSAGE_TYPE:
+ case DHCP_REQUESTED_ADDRESS:
+ /* These options have to be within the main options
+ * block. This doesn't seem to be required by the
+ * RFCs, but at least ISC dhcpd refuses to recognise
+ * them otherwise.
+ */
+ options = &dhcppkt->options[OPTS_MAIN];
+ break;
default:
/* Continue processing as normal */
break;
}
/* Set option in first available options block */
- for ( options = dhcppkt->options ;
- options < &dhcppkt->options[NUM_OPT_BLOCKS] ; options++ ) {
+ for ( ; options < &dhcppkt->options[NUM_OPT_BLOCKS] ; options++ ) {
option = set_dhcp_option ( options, tag, data, len );
if ( option )
break;
@@ -144,7 +152,40 @@ static int set_dhcp_packet_option ( struct dhcp_packet *dhcppkt,
}
/**
- * Set options within DHCP packet
+ * Copy option into DHCP packet
+ *
+ * @v dhcppkt DHCP packet
+ * @v options DHCP option block, or NULL
+ * @v tag DHCP option tag to search for
+ * @v new_tag DHCP option tag to use for copied option
+ * @ret rc Return status code
+ *
+ * Copies a single option, if present, from the DHCP options block
+ * into a DHCP packet. The tag for the option may be changed if
+ * desired; this is required by other parts of the DHCP code.
+ *
+ * @c options may specify a single options block, or be left as NULL
+ * in order to search for the option within all registered options
+ * blocks.
+ */
+static int copy_dhcp_packet_option ( struct dhcp_packet *dhcppkt,
+ struct dhcp_option_block *options,
+ unsigned int tag, unsigned int new_tag ) {
+ struct dhcp_option *option;
+ int rc;
+
+ option = find_dhcp_option ( options, tag );
+ if ( option ) {
+ if ( ( rc = set_dhcp_packet_option ( dhcppkt, new_tag,
+ &option->data,
+ option->len ) ) != 0 )
+ return rc;
+ }
+ return 0;
+}
+
+/**
+ * Copy options into DHCP packet
*
* @v dhcppkt DHCP packet
* @v options DHCP option block, or NULL
@@ -158,12 +199,11 @@ static int set_dhcp_packet_option ( struct dhcp_packet *dhcppkt,
* @c options may specify a single options block, or be left as NULL
* in order to copy options from all registered options blocks.
*/
-static int set_dhcp_packet_encap_options ( struct dhcp_packet *dhcppkt,
- struct dhcp_option_block *options,
- unsigned int encapsulator ) {
+static int copy_dhcp_packet_encap_options ( struct dhcp_packet *dhcppkt,
+ struct dhcp_option_block *options,
+ unsigned int encapsulator ) {
unsigned int subtag;
unsigned int tag;
- struct dhcp_option *option;
int rc;
for ( subtag = DHCP_MIN_OPTION; subtag <= DHCP_MAX_OPTION; subtag++ ) {
@@ -172,19 +212,15 @@ static int set_dhcp_packet_encap_options ( struct dhcp_packet *dhcppkt,
case DHCP_EB_ENCAP:
case DHCP_VENDOR_ENCAP:
/* Process encapsulated options field */
- if ( ( rc = set_dhcp_packet_encap_options ( dhcppkt,
- options,
- tag )) !=0)
+ if ( ( rc = copy_dhcp_packet_encap_options ( dhcppkt,
+ options,
+ tag)) !=0)
return rc;
break;
default:
/* Copy option to reassembled packet */
- option = find_dhcp_option ( options, tag );
- if ( ! option )
- break;
- if ( ( rc = set_dhcp_packet_option ( dhcppkt, tag,
- &option->data,
- option->len)) !=0)
+ if ( ( rc = copy_dhcp_packet_option ( dhcppkt, options,
+ tag, tag ) ) !=0)
return rc;
break;
};
@@ -194,7 +230,7 @@ static int set_dhcp_packet_encap_options ( struct dhcp_packet *dhcppkt,
}
/**
- * Set options within DHCP packet
+ * Copy options into DHCP packet
*
* @v dhcppkt DHCP packet
* @v options DHCP option block, or NULL
@@ -207,9 +243,9 @@ static int set_dhcp_packet_encap_options ( struct dhcp_packet *dhcppkt,
* @c options may specify a single options block, or be left as NULL
* in order to copy options from all registered options blocks.
*/
-static int set_dhcp_packet_options ( struct dhcp_packet *dhcppkt,
- struct dhcp_option_block *options ) {
- return set_dhcp_packet_encap_options ( dhcppkt, options, 0 );
+static int copy_dhcp_packet_options ( struct dhcp_packet *dhcppkt,
+ struct dhcp_option_block *options ) {
+ return copy_dhcp_packet_encap_options ( dhcppkt, options, 0 );
}
/**
@@ -224,7 +260,7 @@ static int set_dhcp_packet_options ( struct dhcp_packet *dhcppkt,
*
* Creates a DHCP packet in the specified buffer, and fills out a @c
* dhcp_packet structure that can be passed to
- * set_dhcp_packet_option() or set_dhcp_packet_options().
+ * set_dhcp_packet_option() or copy_dhcp_packet_options().
*/
static int create_dhcp_packet ( struct dhcp_session *dhcp, uint8_t msgtype,
void *data, size_t max_len,
@@ -232,6 +268,7 @@ static int create_dhcp_packet ( struct dhcp_session *dhcp, uint8_t msgtype,
struct dhcphdr *dhcphdr = data;
static const uint8_t overloading = ( DHCP_OPTION_OVERLOAD_FILE |
DHCP_OPTION_OVERLOAD_SNAME );
+ int rc;
/* Sanity check */
if ( max_len < sizeof ( *dhcphdr ) )
@@ -263,14 +300,11 @@ static int create_dhcp_packet ( struct dhcp_session *dhcp, uint8_t msgtype,
sizeof ( overloading ) ) == NULL )
return -ENOSPC;
- /* Set DHCP_MESSAGE_TYPE option within the main options block.
- * This doesn't seem to be required by the RFCs, but at least
- * ISC dhcpd and ethereal refuse to recognise it otherwise.
- */
- if ( set_dhcp_option ( &dhcppkt->options[OPTS_MAIN],
- DHCP_MESSAGE_TYPE, &msgtype,
- sizeof ( msgtype ) ) == NULL )
- return -ENOSPC;
+ /* Set DHCP_MESSAGE_TYPE option */
+ if ( ( rc = set_dhcp_packet_option ( dhcppkt, DHCP_MESSAGE_TYPE,
+ &msgtype,
+ sizeof ( msgtype ) ) ) != 0 )
+ return rc;
return 0;
}
@@ -435,6 +469,17 @@ udp_to_dhcp ( struct udp_connection *conn ) {
return container_of ( conn, struct dhcp_session, udp );
}
+/**
+ * Mark DHCP session as complete
+ *
+ * @v dhcp DHCP session
+ * @v rc Return status code
+ */
+static void dhcp_done ( struct dhcp_session *dhcp, int rc ) {
+ /* Mark async operation as complete */
+ async_done ( &dhcp->aop, rc );
+}
+
/** Address for transmitting DHCP requests */
static struct sockaddr sa_dhcp_server = {
.sa_family = AF_INET,
@@ -470,12 +515,28 @@ static void dhcp_senddata ( struct udp_connection *conn,
}
/* Copy in options common to all requests */
- if ( ( rc = set_dhcp_packet_options ( &dhcppkt,
- &dhcp_request_options ) ) != 0 ){
+ if ( ( rc = copy_dhcp_packet_options ( &dhcppkt,
+ &dhcp_request_options ) ) != 0){
DBG ( "Could not set common DHCP options\n" );
return;
}
+ /* Copy any required options from previous server repsonse */
+ if ( dhcp->options ) {
+ if ( ( rc = copy_dhcp_packet_option ( &dhcppkt, dhcp->options,
+ DHCP_SERVER_IDENTIFIER,
+ DHCP_SERVER_IDENTIFIER ) ) != 0 ) {
+ DBG ( "Could not set server identifier option\n" );
+ return;
+ }
+ if ( ( rc = copy_dhcp_packet_option ( &dhcppkt, dhcp->options,
+ DHCP_EB_YIADDR,
+ DHCP_REQUESTED_ADDRESS ) ) != 0 ) {
+ DBG ( "Could not set requested address option\n" );
+ return;
+ }
+ }
+
/* Transmit the packet */
if ( ( rc = udp_sendto ( conn, &sa_dhcp_server,
dhcppkt.dhcphdr, dhcppkt.len ) ) != 0 ) {
@@ -485,6 +546,33 @@ static void dhcp_senddata ( struct udp_connection *conn,
}
/**
+ * Transmit DHCP request
+ *
+ * @v dhcp DHCP session
+ */
+static void dhcp_send_request ( struct dhcp_session *dhcp ) {
+ start_timer ( &dhcp->timer );
+ udp_senddata ( &dhcp->udp );
+}
+
+/**
+ * Handle DHCP retry timer expiry
+ *
+ * @v timer DHCP retry timer
+ * @v fail Failure indicator
+ */
+static void dhcp_timer_expired ( struct retry_timer *timer, int fail ) {
+ struct dhcp_session *dhcp =
+ container_of ( timer, struct dhcp_session, timer );
+
+ if ( fail ) {
+ dhcp_done ( dhcp, -ETIMEDOUT );
+ } else {
+ dhcp_send_request ( dhcp );
+ }
+}
+
+/**
* Receive new data
*
* @v udp UDP connection
@@ -496,6 +584,7 @@ static void dhcp_newdata ( struct udp_connection *conn,
struct dhcp_session *dhcp = udp_to_dhcp ( conn );
struct dhcphdr *dhcphdr = data;
struct dhcp_option_block *options;
+ unsigned int msgtype;
/* Check for matching transaction ID */
if ( dhcphdr->xid != dhcp->xid ) {
@@ -511,12 +600,42 @@ static void dhcp_newdata ( struct udp_connection *conn,
return;
}
- DBG ( "Received %s\n",
- dhcp_msgtype_name ( find_dhcp_num_option ( options,
- DHCP_MESSAGE_TYPE )));
+ /* Determine message type */
+ msgtype = find_dhcp_num_option ( options, DHCP_MESSAGE_TYPE );
+ DBG ( "Received %s\n", dhcp_msgtype_name ( msgtype ) );
+
+ /* Handle DHCP reply */
+ switch ( dhcp->state ) {
+ case DHCPDISCOVER:
+ if ( msgtype != DHCPOFFER )
+ goto out_discard;
+ dhcp->state = DHCPREQUEST;
+ break;
+ case DHCPREQUEST:
+ if ( msgtype != DHCPACK )
+ goto out_discard;
+ dhcp->state = DHCPACK;
+ break;
+ default:
+ assert ( 0 );
+ goto out_discard;
+ }
+
+ /* Stop timer and update stored options */
+ stop_timer ( &dhcp->timer );
+ if ( dhcp->options )
+ free_dhcp_options ( dhcp->options );
+ dhcp->options = options;
- /* Proof of concept: just dump out the parsed options */
- hex_dump ( options->data, options->len );
+ /* Transmit next packet, or terminate session */
+ if ( dhcp->state < DHCPACK ) {
+ dhcp_send_request ( dhcp );
+ } else {
+ dhcp_done ( dhcp, 0 );
+ }
+ return;
+
+ out_discard:
free_dhcp_options ( options );
}
@@ -535,7 +654,9 @@ static struct udp_operations dhcp_udp_operations = {
struct async_operation * start_dhcp ( struct dhcp_session *dhcp ) {
int rc;
+ /* Initialise DHCP session */
dhcp->udp.udp_op = &dhcp_udp_operations;
+ dhcp->timer.expired = dhcp_timer_expired;
dhcp->state = DHCPDISCOVER;
/* Use least significant 32 bits of link-layer address as XID */
memcpy ( &dhcp->xid, ( dhcp->netdev->ll_addr
@@ -549,7 +670,7 @@ struct async_operation * start_dhcp ( struct dhcp_session *dhcp ) {
}
/* Proof of concept: just send a single DHCPDISCOVER */
- udp_senddata ( &dhcp->udp );
+ dhcp_send_request ( dhcp );
out:
return &dhcp->aop;
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2026-02-28 16:23:59 +0100