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Remove the concept of the media-independent link-layer header and replace 

it with metadata in the pkb structure.  This is required since UNDI will
want to be able to parse the link-layer header without destroying it.
This commit is contained in:
Michael Brown 2006-04-19 11:32:24 +00:00
parent b89ccac02d
commit bdc8190c8d
6 changed files with 194 additions and 126 deletions
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2
src/include/gpxe/arp.h
View File

@ -12,7 +12,7 @@ struct net_interface;
struct pk_buff;
extern int arp_resolve ( struct net_device *netdev, struct pk_buff *pkb,
void *ll_addr );
const void **ll_addr );
extern int arp_process ( struct net_interface *arp_netif,
struct pk_buff *pkb );

63
src/include/gpxe/llh.h
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@ -1,63 +0,0 @@
#ifndef _LLH_H
#define _LLH_H
/** @file
*
* Link-layer headers
*
* This file defines a media-independent link-layer header, used for
* communication between the network and link layers of the stack.
*
*/
#include <stdint.h>
/** Maximum length of a link-layer address */
#define MAX_LLH_ADDR_LEN 6
/** Maximum length of a network-layer address */
#define MAX_NET_ADDR_LEN 4
/* Network-layer address may be required to contain a raw link-layer address */
#if MAX_NET_ADDR_LEN < MAX_LLH_ADDR_LEN
#undef MAX_NET_ADDR_LEN
#define MAX_NET_ADDR_LEN MAX_LLH_ADDR_LEN
#endif
/** A media-independent link-layer header
*
* This structure represents a generic link-layer header. It never
* appears on the wire, but is used to communicate between different
* layers within the gPXE protocol stack.
*/
struct gpxehdr {
/** The network-layer protocol
*
* This is the network-layer protocol expressed as an
* ETH_P_XXX constant, in network-byte order.
*/
uint16_t net_proto;
/** Flags
*
* Filled in only on outgoing packets. Value is the
* bitwise-OR of zero or more GPXE_FL_XXX constants.
*/
uint8_t flags;
/** Network-layer address length
*
* Filled in only on outgoing packets.
*/
uint8_t net_addr_len;
/** Network-layer address
*
* Filled in only on outgoing packets.
*/
uint8_t net_addr[MAX_NET_ADDR_LEN];
} __attribute__ (( packed ));
/* Media-independent link-layer header flags */
#define GPXE_FL_BROADCAST 0x01
#define GPXE_FL_MULTICAST 0x02
#define GPXE_FL_RAW 0x04
#endif /* _LLH_H */

62
src/include/gpxe/netdevice.h
View File

@ -8,13 +8,18 @@
*/
#include <stdint.h>
#include <gpxe/llh.h>
#include <gpxe/list.h>
struct net_device;
struct net_interface;
struct pk_buff;
/** Maximum length of a link-layer address */
#define MAX_LLH_ADDR_LEN 6
/** Maximum length of a network-layer address */
#define MAX_NET_ADDR_LEN 4
/**
* A network device
*
@ -45,7 +50,6 @@ struct net_device {
/** Poll for received packet
*
* @v netdev Network device
* @v retrieve Flag indicating whether or not to retrieve packet
* @v pkb Packet buffer to contain received packet
* @ret rc Return status code
*
@ -53,55 +57,42 @@ struct net_device {
* received packet. If no packet is available, the method
* should return -EAGAIN (i.e. this method is *always*
* considered to be a non-blocking read). If a packet is
* available, but @c retrieve is false, the method should
* return zero for success. If a packet is available and @c
* retrieve is true, the method should fill the packet buffer
* and return zero for success.
* available, the method should fill the packet buffer and
* return zero for success.
*/
int ( * poll ) ( struct net_device *netdev, int retrieve,
struct pk_buff *pkb );
/** Build media-specific link-layer header
int ( * poll ) ( struct net_device *netdev, struct pk_buff *pkb );
/** Build link-layer header
*
* @v netdev Network device
* @v pkb Packet buffer
* @ret rc Return status code
*
* This method should convert the packet buffer's generic
* link-layer header (a struct gpxehdr) into a media-specific
* link-layer header (e.g. a struct ethhdr). The generic
* header should be removed from the buffer (via pkb_pull())
* and the media-specific header should be prepended (via
* pkb_push()) in its place.
* This method should fill in the link-layer header based on
* the metadata contained in @c pkb.
*
* If a link-layer header cannot be constructed (e.g. because
* of a missing ARP cache entry), then this method should
* return an error (after transmitting an ARP request, if
* applicable).
*/
int ( * make_media_header ) ( struct net_device *netdev,
struct pk_buff *pkb );
/** Build media-independent link-layer header
int ( * build_llh ) ( struct net_device *netdev, struct pk_buff *pkb );
/** Parse link-layer header
*
* @v netdev Network device
* @v pkb Packet buffer
* @ret rc Return status code
*
* This method should convert the packet buffer's
* media-specific link-layer header (e.g. a struct ethhdr)
* into a generic link-layer header (a struct gpxehdr). It
* performs the converse function of make_media_header().
*
* Note that the gpxehdr::addr and gpxehdr::addrlen fields
* will not be filled in by this function, since doing so
* would require understanding the network-layer header.
* This method should parse the link-layer header and fill in
* the metadata in @c pkb.
*/
int ( * make_generic_header ) ( struct net_device *netdev,
struct pk_buff *pkb );
int ( * parse_llh ) ( struct net_device *netdev, struct pk_buff *pkb );
/** Link-layer protocol
*
* This is an ARPHRD_XXX constant, in network byte order.
*/
uint16_t ll_proto;
/** Link-layer header length */
uint8_t ll_hlen;
/** Link-layer address length */
uint8_t ll_addr_len;
/** Link-layer address
@ -151,17 +142,18 @@ struct net_interface {
*/
int ( * process ) ( struct net_interface *netif,
struct pk_buff *pkb );
/** Add media-independent link-layer header
/** Fill in packet metadata
*
* @v netif Network interface
* @v pkb Packet buffer
* @ret rc Return status code
*
* This method should prepend a generic link-layer header (a
* struct @c gpxehdr) to the packet buffer using pkb_push().
* This method should fill in the @c pkb metadata with enough
* information to enable net_device::build_llh to construct
* the link-layer header.
*/
int ( * add_generic_header ) ( struct net_interface *netif,
struct pk_buff *pkb );
int ( * add_llh_metadata ) ( struct net_interface *netif,
struct pk_buff *pkb );
};
/**
@ -196,9 +188,7 @@ extern struct net_device static_single_netdev;
extern int register_netdevice ( struct net_device *netdev );
static inline void unregister_netdevice ( struct net_device *netdev __unused ){
/* Do nothing */
}
extern void unregister_netdevice ( struct net_device *netdev );
static inline void free_netdevice ( struct net_device *netdev __unused ) {
/* Do nothing */

32
src/include/gpxe/pkbuff.h
View File

@ -26,8 +26,40 @@ struct pk_buff {
void *tail;
/** End of the buffer */
void *end;
/** The network-layer protocol
*
* This is the network-layer protocol expressed as an
* ETH_P_XXX constant, in network-byte order.
*/
uint16_t net_proto;
/** Flags
*
* Filled in only on outgoing packets. Value is the
* bitwise-OR of zero or more PKB_FL_XXX constants.
*/
uint8_t flags;
/** Network-layer address length
*
* Filled in only on outgoing packets.
*/
uint8_t net_addr_len;
/** Network-layer address
*
* Filled in only on outgoing packets.
*/
void *net_addr;
};
/** Packet is a broadcast packet */
#define PKB_FL_BROADCAST 0x01
/** Packet is a multicast packet */
#define PKB_FL_MULTICAST 0x02
/** Network-layer address is a raw hardware address */
#define PKB_FL_RAW_NET_ADDR 0x04
/**
* Add data to start of packet buffer
*

45
src/net/arp.c
View File

@ -23,7 +23,6 @@
#include <gpxe/if_ether.h>
#include <gpxe/if_arp.h>
#include <gpxe/pkbuff.h>
#include <gpxe/llh.h>
#include <gpxe/netdevice.h>
#include <gpxe/arp.h>
@ -91,45 +90,43 @@ arp_find_entry ( uint16_t ll_proto, uint16_t net_proto, const void *net_addr,
*
* @v netdev Network device
* @v pkb Packet buffer
* @v ll_addr Buffer to contain link-layer address
* @ret ll_addr Pointer to link-layer address
* @ret rc Return status code
*
* The packet buffer must start with a media-independent link-layer
* header (a struct @c gpxehdr). This function will use the ARP cache
* to look up the link-layer address for the media corresponding to
* @c netdev and the network-layer address as specified in @c gpxehdr.
* This function will use the ARP cache to look up the link-layer
* address for the media corresponding to @c netdev and the
* network-layer address as specified in the @c pkb metadata.
*
* If no address is found in the ARP cache, an ARP request will be
* transmitted, -ENOENT will be returned, and the packet buffer
* contents will be undefined.
*/
int arp_resolve ( struct net_device *netdev, struct pk_buff *pkb,
void *ll_addr ) {
struct gpxehdr *gpxehdr = pkb->data;
const void **ll_addr ) {
const struct arp_entry *arp;
struct net_interface *netif;
struct arphdr *arphdr;
/* Look for existing entry in ARP table */
arp = arp_find_entry ( netdev->ll_proto, gpxehdr->net_proto,
gpxehdr->net_addr, gpxehdr->net_addr_len );
arp = arp_find_entry ( netdev->ll_proto, pkb->net_proto,
pkb->net_addr, pkb->net_addr_len );
if ( arp ) {
memcpy ( ll_addr, arp->ll_addr, netdev->ll_addr_len );
*ll_addr = arp->ll_addr;
return 0;
}
/* Find interface for this protocol */
netif = netdev_find_netif ( netdev, gpxehdr->net_proto );
netif = netdev_find_netif ( netdev, pkb->net_proto );
if ( ! netif )
return -EAFNOSUPPORT;
/* Build up ARP request */
pkb_unput ( pkb, pkb_len ( pkb ) - sizeof ( *gpxehdr ) );
pkb_empty ( pkb );
arphdr = pkb_put ( pkb, sizeof ( *arphdr ) );
arphdr->ar_hrd = netdev->ll_proto;
arphdr->ar_hln = netdev->ll_addr_len;
arphdr->ar_pro = gpxehdr->net_proto;
arphdr->ar_pln = gpxehdr->net_addr_len;
arphdr->ar_pro = pkb->net_proto;
arphdr->ar_pln = pkb->net_addr_len;
arphdr->ar_op = htons ( ARPOP_REQUEST );
memcpy ( pkb_put ( pkb, netdev->ll_addr_len ),
netdev->ll_addr, netdev->ll_addr_len );
@ -138,8 +135,7 @@ int arp_resolve ( struct net_device *netdev, struct pk_buff *pkb,
memset ( pkb_put ( pkb, netdev->ll_addr_len ),
0xff, netdev->ll_addr_len );
memcpy ( pkb_put ( pkb, netif->net_addr_len ),
gpxehdr->net_addr, netif->net_addr_len );
pkb_pull ( pkb, sizeof ( *gpxehdr ) );
pkb->net_addr, netif->net_addr_len );
/* Locate ARP interface and send ARP request */
netif = netdev_find_netif ( netdev, htons ( ETH_P_ARP ) );
@ -228,17 +224,14 @@ int arp_process ( struct net_interface *arp_netif, struct pk_buff *pkb ) {
* @v pkb Packet buffer
* @ret rc Return status code
*/
int arp_add_generic_header ( struct net_interface *arp_netif __unused,
struct pk_buff *pkb ) {
int arp_add_llh_metadata ( struct net_interface *arp_netif __unused,
struct pk_buff *pkb ) {
struct arphdr *arphdr = pkb->data;
struct gpxehdr *gpxehdr;
/* We're ARP; we always know the raw link-layer address we want */
gpxehdr = pkb_push ( pkb, sizeof ( *gpxehdr ) );
gpxehdr->net_proto = htons ( ETH_P_ARP );
gpxehdr->flags = GPXE_FL_RAW;
gpxehdr->net_addr_len = arphdr->ar_hln;
memcpy ( gpxehdr->net_addr, arp_target_ha ( arphdr ), arphdr->ar_hln );
pkb->net_proto = htons ( ETH_P_ARP );
pkb->flags = PKB_FL_RAW_NET_ADDR;
pkb->net_addr_len = arphdr->ar_hln;
pkb->net_addr = arp_target_ha ( arphdr );
return 0;
}

116
src/net/ethernet.c Normal file
View File

@ -0,0 +1,116 @@
/*
* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdint.h>
#include <string.h>
#include <byteswap.h>
#include <assert.h>
#include <gpxe/if_ether.h>
#include <gpxe/netdevice.h>
#include <gpxe/pkbuff.h>
#include <gpxe/arp.h>
/** @file
*
* Ethernet protocol
*
*/
/** Ethernet broadcast MAC address */
static uint8_t eth_broadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
/**
* Build Ethernet link-layer header
*
* @v netdev Network device
* @v pkb Packet buffer
* @ret rc Return status code
*
* This constructs the Ethernet link-layer header (destination MAC,
* source MAC, network-layer protocol) based on the metadata found in
* @c pkb.
*
* If the destination MAC address cannot be determined, an ARP request
* is sent for the requested network-layer address instead.
*/
int eth_build_llh ( struct net_device *netdev, struct pk_buff *pkb ) {
struct ethhdr *ethhdr = pkb->data;
const void *eth_dest;
int rc;
/* Do the easy bits */
ethhdr->h_protocol = pkb->net_proto;
memcpy ( ethhdr->h_source, netdev->ll_addr,
sizeof ( ethhdr->h_source ) );
/* Work out the destination MAC address */
if ( pkb->flags & PKB_FL_RAW_NET_ADDR ) {
eth_dest = pkb->net_addr;
} else if ( pkb->flags & PKB_FL_BROADCAST ) {
eth_dest = eth_broadcast;
} else if ( pkb->flags & PKB_FL_MULTICAST ) {
/* IP multicast is a special case; there exists a
* direct mapping from IP address to MAC address
*/
assert ( pkb->net_proto == htons ( ETH_P_IP ) );
ethhdr->h_dest[0] = 0x01;
ethhdr->h_dest[1] = 0x00;
ethhdr->h_dest[2] = 0x5e;
ethhdr->h_dest[3] = *( ( char * ) pkb->net_addr + 1 ) & 0x7f;
ethhdr->h_dest[4] = *( ( char * ) pkb->net_addr + 2 );
ethhdr->h_dest[5] = *( ( char * ) pkb->net_addr + 3 );
eth_dest = ethhdr->h_dest;
} else {
/* Otherwise, look up the address using ARP */
if ( ( rc = arp_resolve ( netdev, pkb, &eth_dest ) ) != 0 )
return rc;
}
/* Fill in destination MAC address */
memcpy ( ethhdr->h_dest, eth_dest, sizeof ( ethhdr->h_dest ) );
return 0;
}
/**
* Parse Ethernet link-layer header
*
* @v netdev Network device
* @v pkb Packet buffer
* @ret rc Return status code
*
* This parses the Ethernet link-layer header (destination MAC, source
* MAC, network-layer protocol) and fills in the metadata in @c pkb.
*/
int eth_parse_llh ( struct net_device *netdev __unused, struct pk_buff *pkb ) {
struct ethhdr *ethhdr = pkb->data;
pkb->net_proto = ethhdr->h_protocol;
pkb->flags = PKB_FL_RAW_NET_ADDR;
pkb->net_addr_len = sizeof ( ethhdr->h_dest );
pkb->net_addr = ethhdr->h_dest;
if ( memcmp ( ethhdr->h_dest, eth_broadcast,
sizeof ( ethhdr->h_dest ) ) == 0 ) {
pkb->flags |= PKB_FL_BROADCAST;
} else if ( ethhdr->h_dest[0] & 0x01 ) {
pkb->flags |= PKB_FL_MULTICAST;
}
return 0;
}