mirror of
https://github.com/ipxe/ipxe
synced 2025-12-12 06:22:01 +03:00
Simplify RX data path.
Kill off the static single net device and move to proper dynamic registration (which we need with the new device model). Break the (flawed) assumption that all network-layer protocols can use ARP; such network-layer protocols (i.e. IPv4) must now register as an ARP protocol using ARP_NET_PROTOCOL() and provide a single method for checking the existence of a local network-layer address.
This commit is contained in:
Michael Brown
@@ -20,6 +20,7 @@
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#include <byteswap.h>
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#include <string.h>
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#include <errno.h>
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#include <malloc.h>
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#include <gpxe/if_ether.h>
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#include <gpxe/pkbuff.h>
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#include <gpxe/tables.h>
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@@ -33,39 +34,141 @@
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*
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*/
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/**
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* Static single instance of a network device
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*
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* The gPXE API is designed to accommodate multiple network devices.
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* However, in the interests of code size, the implementation behind
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* the API supports only a single instance of a network device.
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*
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* No code outside of netdevice.c should ever refer directly to @c
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* static_single_netdev.
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*
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* Callers should always check the return status of alloc_netdev(),
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* register_netdev() etc. In the current implementation this code
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* will be optimised out by the compiler, so there is no penalty.
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*/
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struct net_device static_single_netdev;
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/** Registered network-layer protocols */
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static struct net_protocol net_protocols[0] __table_start ( net_protocols );
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static struct net_protocol net_protocols_end[0] __table_end ( net_protocols );
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/** Network-layer addresses for @c static_single_netdev */
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static struct net_address static_single_netdev_addresses[0]
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__table_start ( sgl_netdev_addresses );
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static struct net_address static_single_netdev_addresses_end[0]
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__table_end ( sgl_netdev_addresses );
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/** Recevied packet queue */
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static LIST_HEAD ( rx_queue );
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/** List of network devices */
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static LIST_HEAD ( net_devices );
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#warning "Remove this static IP address hack"
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#include <ip.h>
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#include <gpxe/ip.h>
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/**
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* Transmit raw packet via network device
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*
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* @v netdev Network device
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* @v pkb Packet buffer
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* @ret rc Return status code
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*
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* Transmits the packet via the specified network device. This
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* function takes ownership of the packet buffer.
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*/
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int netdev_tx ( struct net_device *netdev, struct pk_buff *pkb ) {
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DBG ( "%s transmitting %p+%zx\n", netdev_name ( netdev ),
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pkb->data, pkb_len ( pkb ) );
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return netdev->transmit ( netdev, pkb );
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}
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/**
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* Add packet to receive queue
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*
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* @v netdev Network device
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* @v pkb Packet buffer
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*
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* The packet is added to the network device's RX queue. This
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* function takes ownership of the packet buffer.
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*/
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void netdev_rx ( struct net_device *netdev, struct pk_buff *pkb ) {
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DBG ( "%s received %p+%zx\n", netdev_name ( netdev ),
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pkb->data, pkb_len ( pkb ) );
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list_add_tail ( &pkb->list, &netdev->rx_queue );
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}
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/**
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* Transmit network-layer packet
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*
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* @v pkb Packet buffer
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* @v netdev Network device
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* @v net_protocol Network-layer protocol
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* @v ll_dest Destination link-layer address
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* @ret rc Return status code
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*
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* Prepends link-layer headers to the packet buffer and transmits the
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* packet via the specified network device. This function takes
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* ownership of the packet buffer.
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*/
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int net_tx ( struct pk_buff *pkb, struct net_device *netdev,
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struct net_protocol *net_protocol, const void *ll_dest ) {
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return netdev->ll_protocol->tx ( pkb, netdev, net_protocol, ll_dest );
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}
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/**
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* Process received network-layer packet
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*
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* @v pkb Packet buffer
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* @v netdev Network device
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* @v net_proto Network-layer protocol, in network-byte order
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* @v ll_source Source link-layer address
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*/
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void net_rx ( struct pk_buff *pkb, struct net_device *netdev,
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uint16_t net_proto, const void *ll_source ) {
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struct net_protocol *net_protocol;
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/* Hand off to network-layer protocol, if any */
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for ( net_protocol = net_protocols ; net_protocol < net_protocols_end ;
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net_protocol++ ) {
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if ( net_protocol->net_proto == net_proto ) {
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net_protocol->rx ( pkb, netdev, ll_source );
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break;
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}
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}
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}
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/**
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* Poll for packet on network device
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*
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* @v netdev Network device
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* @ret True There are packets present in the receive queue
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* @ret False There are no packets present in the receive queue
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*
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* Polls the network device for received packets. Any received
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* packets will be added to the RX packet queue via netdev_rx().
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*/
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int netdev_poll ( struct net_device *netdev ) {
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netdev->poll ( netdev );
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return ( ! list_empty ( &netdev->rx_queue ) );
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}
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/**
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* Remove packet from device's receive queue
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*
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* @v netdev Network device
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* @ret pkb Packet buffer, or NULL
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*
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* Removes the first packet from the device's RX queue and returns it.
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* Ownership of the packet is transferred to the caller.
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*/
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struct pk_buff * netdev_rx_dequeue ( struct net_device *netdev ) {
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struct pk_buff *pkb;
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list_for_each_entry ( pkb, &netdev->rx_queue, list ) {
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list_del ( &pkb->list );
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return pkb;
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}
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return NULL;
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}
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/**
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* Allocate network device
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*
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* @v priv_size Size of private data area (net_device::priv)
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* @ret netdev Network device, or NULL
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*
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* Allocates space for a network device and its private data area.
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*/
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struct net_device * alloc_netdev ( size_t priv_size ) {
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struct net_device *netdev;
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netdev = calloc ( 1, sizeof ( *netdev ) + priv_size );
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if ( netdev ) {
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INIT_LIST_HEAD ( &netdev->rx_queue );
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netdev->priv = ( ( ( void * ) netdev ) + sizeof ( *netdev ) );
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}
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return netdev;
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}
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/**
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* Register network device
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*
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@@ -89,6 +192,10 @@ int register_netdev ( struct net_device *netdev ) {
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return rc;
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}
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/* Add to device list */
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list_add_tail ( &netdev->list, &net_devices );
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DBG ( "%s registered\n", netdev_name ( netdev ) );
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return 0;
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}
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@@ -100,157 +207,52 @@ int register_netdev ( struct net_device *netdev ) {
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* Removes the network device from the list of network devices.
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*/
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void unregister_netdev ( struct net_device *netdev ) {
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struct pk_buff *pkb;
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#warning "Remove this static IP address hack"
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del_ipv4_address ( netdev );
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/* Discard any packets in the RX queue */
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while ( ( pkb = netdev_rx_dequeue ( netdev ) ) ) {
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DBG ( "%s discarding %p+%zx\n", netdev_name ( netdev ),
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pkb->data, pkb_len ( pkb ) );
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free_pkb ( pkb );
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}
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/* Remove from device list */
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list_del ( &netdev->list );
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DBG ( "%s unregistered\n", netdev_name ( netdev ) );
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}
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/**
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* Add packet to receive queue
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* Free network device
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*
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* @v netdev Network device
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* @v pkb Packet buffer
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*
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* The packet is added to the RX queue. This function takes ownership
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* of the packet buffer.
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*/
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void netdev_rx ( struct net_device *netdev, struct pk_buff *pkb ) {
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DBG ( "Packet received\n" );
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pkb->ll_protocol = netdev->ll_protocol;
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list_add_tail ( &pkb->list, &rx_queue );
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void free_netdev ( struct net_device *netdev ) {
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free ( netdev );
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}
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/**
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* Identify network protocol
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* Iterate through network devices
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*
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* @v net_proto Network-layer protocol, in network-byte order
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* @ret net_protocol Network-layer protocol, or NULL
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*
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* Identify a network-layer protocol from a protocol number, which
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* must be an ETH_P_XXX constant in network-byte order.
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*/
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struct net_protocol * find_net_protocol ( uint16_t net_proto ) {
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struct net_protocol *net_protocol;
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for ( net_protocol = net_protocols ; net_protocol < net_protocols_end ;
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net_protocol++ ) {
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if ( net_protocol->net_proto == net_proto )
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return net_protocol;
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}
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return NULL;
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}
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/**
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* Identify network device by network-layer address
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*
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* @v net_protocol Network-layer protocol
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* @v net_addr Network-layer address
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* @ret netdev Network device, or NULL
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*
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* Searches through all network devices to find the device with the
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* specified network-layer address.
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*
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* Note that even with a static single network device, this function
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* can still return NULL.
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* This returns the registered network devices in the order of
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* registration. If no network devices are registered, it will return
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* NULL.
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*/
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struct net_device *
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find_netdev_by_net_addr ( struct net_protocol *net_protocol,
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void *net_addr ) {
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struct net_address *net_address;
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struct net_device *netdev = &static_single_netdev;
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for ( net_address = static_single_netdev_addresses ;
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net_address < static_single_netdev_addresses_end ;
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net_address ++ ) {
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if ( ( net_address->net_protocol == net_protocol ) &&
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( memcmp ( net_address->net_addr, net_addr,
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net_protocol->net_addr_len ) == 0 ) )
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return netdev;
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}
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struct net_device * next_netdev ( void ) {
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struct net_device *netdev;
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return NULL;
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}
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/**
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* Poll for packet on all network devices
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*
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* @ret True There are packets present in the receive queue
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* @ret False There are no packets present in the receive queue
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*
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* Polls all network devices for received packets. Any received
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* packets will be added to the RX packet queue via netdev_rx().
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*/
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int net_poll ( void ) {
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struct net_device *netdev = &static_single_netdev;
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DBG ( "Polling network\n" );
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netdev->poll ( netdev );
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return ( ! list_empty ( &rx_queue ) );
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}
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/**
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* Remove packet from receive queue
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*
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* @ret pkb Packet buffer, or NULL
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*
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* Removes the first packet from the RX queue and returns it.
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* Ownership of the packet is transferred to the caller.
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*/
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struct pk_buff * net_rx_dequeue ( void ) {
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struct pk_buff *pkb;
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list_for_each_entry ( pkb, &rx_queue, list ) {
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list_del ( &pkb->list );
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return pkb;
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list_for_each_entry ( netdev, &net_devices, list ) {
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list_del ( &netdev->list );
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list_add_tail ( &netdev->list, &net_devices );
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return netdev;
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}
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return NULL;
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}
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/**
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* Process received packet
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*
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* @v pkb Packet buffer
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* @ret rc Return status code
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*
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* Processes a packet received from the network (and, usually, removed
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* from the RX queue by net_rx_dequeue()). This call takes ownership
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* of the packet buffer.
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*/
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int net_rx_process ( struct pk_buff *pkb ) {
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struct ll_protocol *ll_protocol;
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struct ll_header llhdr;
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struct net_protocol *net_protocol;
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int rc;
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/* Parse link-layer header */
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ll_protocol = pkb->ll_protocol;
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ll_protocol->parse_llh ( pkb, &llhdr );
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/* Identify network-layer protocol */
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net_protocol = find_net_protocol ( llhdr.net_proto );
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if ( ! net_protocol ) {
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DBG ( "Unknown network-layer protocol %x\n",
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ntohs ( llhdr.net_proto ) );
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free_pkb ( pkb );
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return -EPROTONOSUPPORT;
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}
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pkb->net_protocol = net_protocol;
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/* Strip off link-layer header */
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#warning "Temporary hack"
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pkb_pull ( pkb, ETH_HLEN );
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/* Hand off to network layer */
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if ( ( rc = net_protocol->rx_process ( pkb ) ) != 0 ) {
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DBG ( "Network-layer protocol dropped packet\n" );
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return rc;
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}
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return 0;
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}
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/**
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* Single-step the network stack
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*
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@@ -266,15 +268,21 @@ int net_rx_process ( struct pk_buff *pkb ) {
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* multiple packets are processed per poll.
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*/
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static void net_step ( struct process *process ) {
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struct net_device *netdev;
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struct pk_buff *pkb;
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/* Poll for new packets */
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net_poll();
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/* Poll and process each network device */
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list_for_each_entry ( netdev, &net_devices, list ) {
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/* Handle at most one received packet */
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if ( ( pkb = net_rx_dequeue () ) ) {
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net_rx_process ( pkb );
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DBG ( "Processed received packet\n" );
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/* Poll for new packets */
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netdev_poll ( netdev );
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/* Handle at most one received packet per poll */
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if ( ( pkb = netdev_rx_dequeue ( netdev ) ) ) {
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DBG ( "%s processing %p+%zx\n", netdev_name ( netdev ),
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pkb->data, pkb_len ( pkb ) );
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netdev->ll_protocol->rx ( pkb, netdev );
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}
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}
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/* Re-schedule ourself */
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Block a user