net/802/fddi.c

Source file repositories/reference/linux-study-clean/net/802/fddi.c

File Facts

System
Linux kernel
Corpus path
net/802/fddi.c
Extension
.c
Size
5001 bytes
Lines
185
Domain
Networking Core
Bucket
Sockets, Protocols, Packet Path, And Network Policy
Inferred role
Networking Core: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		FDDI-type device handling.
 *
 * Version:	@(#)fddi.c	1.0.0	08/12/96
 *
 * Authors:	Lawrence V. Stefani, <stefani@lkg.dec.com>
 *
 *		fddi.c is based on previous eth.c and tr.c work by
 *			Ross Biro
 *			Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *			Mark Evans, <evansmp@uhura.aston.ac.uk>
 *			Florian La Roche, <rzsfl@rz.uni-sb.de>
 *			Alan Cox, <gw4pts@gw4pts.ampr.org>
 *
 *	Changes
 *		Alan Cox		:	New arp/rebuild header
 *		Maciej W. Rozycki	:	IPv6 support
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/fddidevice.h>
#include <linux/if_ether.h>
#include <linux/skbuff.h>
#include <linux/errno.h>
#include <net/arp.h>
#include <net/sock.h>

/*
 * Create the FDDI MAC header for an arbitrary protocol layer
 *
 * saddr=NULL	means use device source address
 * daddr=NULL	means leave destination address (eg unresolved arp)
 */

static int fddi_header(struct sk_buff *skb, struct net_device *dev,
		       unsigned short type,
		       const void *daddr, const void *saddr, unsigned int len)
{
	int hl = FDDI_K_SNAP_HLEN;
	struct fddihdr *fddi;

	if(type != ETH_P_IP && type != ETH_P_IPV6 && type != ETH_P_ARP)
		hl=FDDI_K_8022_HLEN-3;
	fddi = skb_push(skb, hl);
	fddi->fc			 = FDDI_FC_K_ASYNC_LLC_DEF;
	if(type == ETH_P_IP || type == ETH_P_IPV6 || type == ETH_P_ARP)
	{
		fddi->hdr.llc_snap.dsap		 = FDDI_EXTENDED_SAP;
		fddi->hdr.llc_snap.ssap		 = FDDI_EXTENDED_SAP;
		fddi->hdr.llc_snap.ctrl		 = FDDI_UI_CMD;
		fddi->hdr.llc_snap.oui[0]	 = 0x00;
		fddi->hdr.llc_snap.oui[1]	 = 0x00;
		fddi->hdr.llc_snap.oui[2]	 = 0x00;
		fddi->hdr.llc_snap.ethertype	 = htons(type);
	}

	/* Set the source and destination hardware addresses */

	if (saddr != NULL)
		memcpy(fddi->saddr, saddr, dev->addr_len);
	else
		memcpy(fddi->saddr, dev->dev_addr, dev->addr_len);

	if (daddr != NULL)
	{
		memcpy(fddi->daddr, daddr, dev->addr_len);
		return hl;
	}

	return -hl;
}

/*
 * Determine the packet's protocol ID and fill in skb fields.
 * This routine is called before an incoming packet is passed
 * up.  It's used to fill in specific skb fields and to set
 * the proper pointer to the start of packet data (skb->data).

Annotation

Implementation Notes