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Network API now allows for multiple network devices (although the

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implementation allows for only one, and does so without compromising on
the efficiency of static allocation).

Link-layer protocols are cleanly separated from the device drivers.

Network-layer protocols are cleanly separated from individual network
devices.

Link-layer and network-layer protocols are cleanly separated from each
other.
This commit is contained in:
Michael Brown
2006-04-24 15:33:06 +00:00
parent 0d97f0d482
commit fdc2ee79db
8 changed files with 768 additions and 529 deletions
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117
src/net/ethernet.c
View File

@@ -20,10 +20,12 @@
#include <string.h>
#include <byteswap.h>
#include <assert.h>
#include <gpxe/if_arp.h>
#include <gpxe/if_ether.h>
#include <gpxe/netdevice.h>
#include <gpxe/pkbuff.h>
#include <gpxe/arp.h>
#include <gpxe/ethernet.h>
/** @file
*
@@ -32,85 +34,104 @@
*/
/** Ethernet broadcast MAC address */
static uint8_t eth_broadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
static uint8_t eth_broadcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
/**
* Build Ethernet link-layer header
* Perform Ethernet routing
*
* @v netdev Network device
* @v pkb Packet buffer
* @v nethdr Generic network-layer header
* @ret llhdr Generic link-layer header
* @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.
* Constructs the generic link-layer header based on the generic
* network-layer header, i.e. maps network-layer addresses (e.g. IPv4
* addresses) to MAC addresses.
*
* If the destination MAC address cannot be determined, an ARP request
* is sent for the requested network-layer address instead.
* is sent for the requested network-layer address and -ENOENT is
* returned.
*/
int eth_build_llh ( struct net_device *netdev, struct pk_buff *pkb ) {
struct ethhdr *ethhdr = pkb->data;
const void *eth_dest;
static int eth_route ( const struct net_header *nethdr,
struct ll_header *llhdr ) {
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 ) {
if ( nethdr->dest_flags & NETADDR_FL_RAW ) {
memcpy ( llhdr->dest_ll_addr, nethdr->dest_net_addr, ETH_ALEN);
} else if ( nethdr->dest_flags & NETADDR_FL_BROADCAST ) {
memcpy ( llhdr->dest_ll_addr, eth_broadcast, ETH_ALEN );
} else if ( nethdr->dest_flags & NETADDR_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;
assert ( nethdr->net_protocol->net_proto == htons(ETH_P_IP) );
llhdr->dest_ll_addr[0] = 0x01;
llhdr->dest_ll_addr[1] = 0x00;
llhdr->dest_ll_addr[2] = 0x5e;
llhdr->dest_ll_addr[3] = nethdr->dest_net_addr[1] & 0x7f;
llhdr->dest_ll_addr[4] = nethdr->dest_net_addr[2];
llhdr->dest_ll_addr[5] = nethdr->dest_net_addr[3];
} else {
/* Otherwise, look up the address using ARP */
if ( ( rc = arp_resolve ( netdev, pkb, &eth_dest ) ) != 0 )
if ( ( rc = arp_resolve ( nethdr, llhdr ) ) != 0 )
return rc;
}
/* Fill in destination MAC address */
memcpy ( ethhdr->h_dest, eth_dest, sizeof ( ethhdr->h_dest ) );
return 0;
}
/**
* Fill in Ethernet link-layer header
*
* @v pkb Packet buffer
* @v llhdr Generic link-layer header
*
* Fills in the Ethernet link-layer header in the packet buffer based
* on information in the generic link-layer header.
*/
static void eth_fill_llh ( const struct ll_header *llhdr,
struct pk_buff *pkb ) {
struct ethhdr *ethhdr = pkb->data;
memcpy ( ethhdr->h_dest, llhdr->dest_ll_addr, ETH_ALEN );
memcpy ( ethhdr->h_source, llhdr->source_ll_addr, ETH_ALEN );
ethhdr->h_protocol = llhdr->net_proto;
}
/**
* Parse Ethernet link-layer header
*
* @v netdev Network device
* @v pkb Packet buffer
* @ret rc Return status code
* @v llhdr Generic link-layer header
*
* This parses the Ethernet link-layer header (destination MAC, source
* MAC, network-layer protocol) and fills in the metadata in @c pkb.
* Fills in the generic link-layer header based on information in the
* Ethernet link-layer header in the packet buffer.
*/
int eth_parse_llh ( struct net_device *netdev __unused, struct pk_buff *pkb ) {
static void eth_parse_llh ( const struct pk_buff *pkb,
struct ll_header *llhdr ) {
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;
memcpy ( llhdr->dest_ll_addr, ethhdr->h_dest, ETH_ALEN );
memcpy ( llhdr->source_ll_addr, ethhdr->h_source, ETH_ALEN );
llhdr->net_proto = ethhdr->h_protocol;
if ( memcmp ( ethhdr->h_dest, eth_broadcast,
sizeof ( ethhdr->h_dest ) ) == 0 ) {
pkb->flags |= PKB_FL_BROADCAST;
if ( memcmp ( ethhdr->h_dest, eth_broadcast, ETH_ALEN ) == 0 ) {
llhdr->dest_flags = NETADDR_FL_BROADCAST;
} else if ( ethhdr->h_dest[0] & 0x01 ) {
pkb->flags |= PKB_FL_MULTICAST;
llhdr->dest_flags = NETADDR_FL_MULTICAST;
} else {
llhdr->dest_flags = 0;
}
return 0;
}
/** Ethernet protocol */
struct ll_protocol ethernet_protocol = {
.ll_proto = htons ( ARPHRD_ETHER ),
.ll_addr_len = ETH_ALEN,
.ll_header_len = ETH_HLEN,
.route = eth_route,
.fill_llh = eth_fill_llh,
.parse_llh = eth_parse_llh,
};
LL_PROTOCOL ( ethernet_protocol );