Derive xid dynamically from the netdev, so that we can call

create_dhcp_packet() from pxe_preboot.c, after the dhcp_session is long
gone.

Expose the functions required by pxe_preboot.c

diff --git a/src/include/gpxe/dhcp.h b/src/include/gpxe/dhcp.h
index 5f1943e..10e4231 100644 (file)
--- a/src/include/gpxe/dhcp.h
+++ b/src/include/gpxe/dhcp.h
@@ -426,8 +426,6 @@ struct dhcp_session {
        /** 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
@@ -467,6 +465,12 @@ extern void find_global_dhcp_ipv4_option ( unsigned int tag,
 extern void delete_dhcp_option ( struct dhcp_option_block *options,
                                 unsigned int tag );
 
+extern struct dhcp_option_block dhcp_request_options;
+extern int create_dhcp_packet ( struct net_device *netdev, uint8_t msgtype,
+                               void *data, size_t max_len,
+                               struct dhcp_packet *dhcppkt );
+extern int copy_dhcp_packet_options ( struct dhcp_packet *dhcppkt,
+                                     struct dhcp_option_block *options );
 extern struct async_operation * start_dhcp ( struct dhcp_session *dhcp );
 
 #endif /* _GPXE_DHCP_H */

diff --git a/src/net/udp/dhcp.c b/src/net/udp/dhcp.c
index 800e9b3..cd8a159 100644 (file)
--- a/src/net/udp/dhcp.c
+++ b/src/net/udp/dhcp.c
@@ -80,8 +80,25 @@ static inline const char * dhcp_msgtype_name ( unsigned int msgtype ) {
        }
 }
 
+/**
+ * Calculate DHCP transaction ID for a network device
+ *
+ * @v netdev           Network device
+ * @ret xid            DHCP XID
+ *
+ * Extract the least significant bits of the hardware address for use
+ * as the transaction ID.
+ */
+static uint32_t dhcp_xid ( struct net_device *netdev ) {
+       uint32_t xid;
+
+       memcpy ( &xid, ( netdev->ll_addr + netdev->ll_protocol->ll_addr_len
+                        - sizeof ( xid ) ), sizeof ( xid ) );
+       return xid;
+}
+
 /** Options common to all DHCP requests */
-static struct dhcp_option_block dhcp_request_options = {
+struct dhcp_option_block dhcp_request_options = {
        .data = dhcp_request_options_data,
        .max_len = sizeof ( dhcp_request_options_data ),
        .len = sizeof ( dhcp_request_options_data ),
@@ -245,15 +262,15 @@ static int copy_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 copy_dhcp_packet_options ( struct dhcp_packet *dhcppkt,
-                                     struct dhcp_option_block *options ) {
+int copy_dhcp_packet_options ( struct dhcp_packet *dhcppkt,
+                              struct dhcp_option_block *options ) {
        return copy_dhcp_packet_encap_options ( dhcppkt, options, 0 );
 }
 
 /**
  * Create a DHCP packet
  *
- * @v dhcp             DHCP session
+ * @v netdev           Network device
  * @v msgtype          DHCP message type
  * @v data             Buffer for DHCP packet
  * @v max_len          Size of DHCP packet buffer
@@ -264,9 +281,9 @@ static int copy_dhcp_packet_options ( struct dhcp_packet *dhcppkt,
  * dhcp_packet structure that can be passed to
  * 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,
-                               struct dhcp_packet *dhcppkt ) {
+int create_dhcp_packet ( struct net_device *netdev, uint8_t msgtype,
+                        void *data, size_t max_len,
+                        struct dhcp_packet *dhcppkt ) {
        struct dhcphdr *dhcphdr = data;
        static const uint8_t overloading = ( DHCP_OPTION_OVERLOAD_FILE |
                                             DHCP_OPTION_OVERLOAD_SNAME );
@@ -278,11 +295,11 @@ static int create_dhcp_packet ( struct dhcp_session *dhcp, uint8_t msgtype,
 
        /* Initialise DHCP packet content */
        memset ( dhcphdr, 0, max_len );
-       dhcphdr->xid = dhcp->xid;
+       dhcphdr->xid = dhcp_xid ( netdev );
        dhcphdr->magic = htonl ( DHCP_MAGIC_COOKIE );
-       dhcphdr->htype = ntohs ( dhcp->netdev->ll_protocol->ll_proto );
-       dhcphdr->hlen = dhcp->netdev->ll_protocol->ll_addr_len;
-       memcpy ( dhcphdr->chaddr, dhcp->netdev->ll_addr, dhcphdr->hlen );
+       dhcphdr->htype = ntohs ( netdev->ll_protocol->ll_proto );
+       dhcphdr->hlen = netdev->ll_protocol->ll_addr_len;
+       memcpy ( dhcphdr->chaddr, netdev->ll_addr, dhcphdr->hlen );
        dhcphdr->op = dhcp_op[msgtype];
 
        /* Initialise DHCP packet structure */
@@ -522,7 +539,7 @@ static int dhcp_senddata ( struct udp_connection *conn,
                 ( dhcp->state == DHCPREQUEST ) );
 
        /* Create DHCP packet in temporary buffer */
-       if ( ( rc = create_dhcp_packet ( dhcp, dhcp->state, buf, len,
+       if ( ( rc = create_dhcp_packet ( dhcp->netdev, dhcp->state, buf, len,
                                         &dhcppkt ) ) != 0 ) {
                DBG ( "Could not create DHCP packet\n" );
                return rc;
@@ -606,9 +623,10 @@ static int dhcp_newdata ( struct udp_connection *conn, void *data, size_t len,
        unsigned int msgtype;
 
        /* Check for matching transaction ID */
-       if ( dhcphdr->xid != dhcp->xid ) {
+       if ( dhcphdr->xid != dhcp_xid ( dhcp->netdev ) ) {
                DBG ( "DHCP wrong transaction ID (wanted %08lx, got %08lx)\n",
-                     ntohl ( dhcphdr->xid ), ntohl ( dhcp->xid ) );
+                     ntohl ( dhcphdr->xid ),
+                     ntohl ( dhcp_xid ( dhcp->netdev ) ) );
                return 0;
        };
 
@@ -683,10 +701,6 @@ struct async_operation * start_dhcp ( struct dhcp_session *dhcp ) {
        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
-                              + dhcp->netdev->ll_protocol->ll_addr_len
-                              - sizeof ( dhcp->xid ) ), sizeof ( dhcp->xid ));
 
        /* Bind to local port */
        if ( ( rc = udp_open ( &dhcp->udp, htons ( BOOTPC_PORT ) ) ) != 0 ) {