/* * 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. * * Ethernet-type device handling. * * Version: @(#)eth.c 1.0.7 05/25/93 * * Authors: Ross Biro * Fred N. van Kempen, * Mark Evans, * Florian La Roche, * Alan Cox, * * Fixes: * Mr Linux : Arp problems * Alan Cox : Generic queue tidyup (very tiny here) * Alan Cox : eth_header ntohs should be htons * Alan Cox : eth_rebuild_header missing an htons and * minor other things. * Tegge : Arp bug fixes. * Florian : Removed many unnecessary functions, code cleanup * and changes for new arp and skbuff. * Alan Cox : Redid header building to reflect new format. * Alan Cox : ARP only when compiled with CONFIG_INET * Greg Page : 802.2 and SNAP stuff. * Alan Cox : MAC layer pointers/new format. * Paul Gortmaker : eth_copy_and_sum shouldn't csum padding. * Alan Cox : Protect against forwarding explosions with * older network drivers and IFF_ALLMULTI. * Christer Weinigel : Better rebuild header message. * Andrew Morton : 26Feb01: kill ether_setup() - use netdev_boot_setup(). * * 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 (at your option) any later version. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include __setup("ether=", netdev_boot_setup); /** * eth_header - create the Ethernet header * @skb: buffer to alter * @dev: source device * @type: Ethernet type field * @daddr: destination address (NULL leave destination address) * @saddr: source address (NULL use device source address) * @len: packet length (<= skb->len) * * * Set the protocol type. For a packet of type ETH_P_802_3 we put the length * in here instead. It is up to the 802.2 layer to carry protocol information. */ int eth_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len) { struct ethhdr *eth = (struct ethhdr *)skb_push(skb, ETH_HLEN); if (type != ETH_P_802_3) eth->h_proto = htons(type); else eth->h_proto = htons(len); /* * Set the source hardware address. */ if (!saddr) saddr = dev->dev_addr; memcpy(eth->h_source, saddr, dev->addr_len); if (daddr) { memcpy(eth->h_dest, daddr, dev->addr_len); return ETH_HLEN; } /* * Anyway, the loopback-device should never use this function... */ if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) { memset(eth->h_dest, 0, dev->addr_len); return ETH_HLEN; } return -ETH_HLEN; } /** * eth_rebuild_header- rebuild the Ethernet MAC header. * @skb: socket buffer to update * * This is called after an ARP or IPV6 ndisc it's resolution on this * sk_buff. We now let protocol (ARP) fill in the other fields. * * This routine CANNOT use cached dst->neigh! * Really, it is used only when dst->neigh is wrong. */ int eth_rebuild_header(struct sk_buff *skb) { struct ethhdr *eth = (struct ethhdr *)skb->data; struct net_device *dev = skb->dev; switch (eth->h_proto) { #ifdef CONFIG_INET case __constant_htons(ETH_P_IP): return arp_find(eth->h_dest, skb); #endif default: printk(KERN_DEBUG "%s: unable to resolve type %X addresses.\n", dev->name, (int)eth->h_proto); memcpy(eth->h_source, dev->dev_addr, dev->addr_len); break; } return 0; } /** * eth_type_trans - determine the packet's protocol ID. * @skb: received socket data * @dev: receiving network device * * The rule here is that we * assume 802.3 if the type field is short enough to be a length. * This is normal practice and works for any 'now in use' protocol. */ __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev) { struct ethhdr *eth; unsigned char *rawp; skb->dev = dev; skb->mac.raw = skb->data; skb_pull(skb, ETH_HLEN); eth = eth_hdr(skb); if (is_multicast_ether_addr(eth->h_dest)) { if (!compare_ether_addr(eth->h_dest, dev->broadcast)) skb->pkt_type = PACKET_BROADCAST; else skb->pkt_type = PACKET_MULTICAST; } /* * This ALLMULTI check should be redundant by 1.4 * so don't forget to remove it. * * Seems, you forgot to remove it. All silly devices * seems to set IFF_PROMISC. */ else if (1 /*dev->flags&IFF_PROMISC */ ) { if (unlikely(compare_ether_addr(eth->h_dest, dev->dev_addr))) skb->pkt_type = PACKET_OTHERHOST; } if (ntohs(eth->h_proto) >= 1536) return eth->h_proto; rawp = skb->data; /* * This is a magic hack to spot IPX packets. Older Novell breaks * the protocol design and runs IPX over 802.3 without an 802.2 LLC * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This * won't work for fault tolerant netware but does for the rest. */ if (*(unsigned short *)rawp == 0xFFFF) return htons(ETH_P_802_3); /* * Real 802.2 LLC */ return htons(ETH_P_802_2); } EXPORT_SYMBOL(eth_type_trans); /** * eth_header_parse - extract hardware address from packet * @skb: packet to extract header from * @haddr: destination buffer */ static int eth_header_parse(struct sk_buff *skb, unsigned char *haddr) { struct ethhdr *eth = eth_hdr(skb); memcpy(haddr, eth->h_source, ETH_ALEN); return ETH_ALEN; } /** * eth_header_cache - fill cache entry from neighbour * @neigh: source neighbour * @hh: destination cache entry * Create an Ethernet header template from the neighbour. */ int eth_header_cache(struct neighbour *neigh, struct hh_cache *hh) { __be16 type = hh->hh_type; struct ethhdr *eth; struct net_device *dev = neigh->dev; eth = (struct ethhdr *) (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth)))); if (type == htons(ETH_P_802_3)) return -1; eth->h_proto = type; memcpy(eth->h_source, dev->dev_addr, dev->addr_len); memcpy(eth->h_dest, neigh->ha, dev->addr_len); hh->hh_len = ETH_HLEN; return 0; } /** * eth_header_cache_update - update cache entry * @hh: destination cache entry * @dev: network device * @haddr: new hardware address * * Called by Address Resolution module to notify changes in address. */ void eth_header_cache_update(struct hh_cache *hh, struct net_device *dev, unsigned char *haddr) { memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)), haddr, dev->addr_len); } /** * eth_mac_addr - set new Ethernet hardware address * @dev: network device * @p: socket address * Change hardware address of device. * * This doesn't change hardware matching, so needs to be overridden * for most real devices. */ static int eth_mac_addr(struct net_device *dev, void *p) { struct sockaddr *addr = p; if (netif_running(dev)) return -EBUSY; memcpy(dev->dev_addr, addr->sa_data, dev->addr_len); return 0; } /** * eth_change_mtu - set new MTU size * @dev: network device * @new_mtu: new Maximum Transfer Unit * * Allow changing MTU size. Needs to be overridden for devices * supporting jumbo frames. */ static int eth_change_mtu(struct net_device *dev, int new_mtu) { if (new_mtu < 68 || new_mtu > ETH_DATA_LEN) return -EINVAL; dev->mtu = new_mtu; return 0; } /** * ether_setup - setup Ethernet network device * @dev: network device * Fill in the fields of the device structure with Ethernet-generic values. */ void ether_setup(struct net_device *dev) { dev->change_mtu = eth_change_mtu; dev->hard_header = eth_header; dev->rebuild_header = eth_rebuild_header; dev->set_mac_address = eth_mac_addr; dev->hard_header_cache = eth_header_cache; dev->header_cache_update= eth_header_cache_update; dev->hard_header_parse = eth_header_parse; dev->type = ARPHRD_ETHER; dev->hard_header_len = ETH_HLEN; dev->mtu = ETH_DATA_LEN; dev->addr_len = ETH_ALEN; dev->tx_queue_len = 1000; /* Ethernet wants good queues */ dev->flags = IFF_BROADCAST|IFF_MULTICAST; memset(dev->broadcast, 0xFF, ETH_ALEN); } EXPORT_SYMBOL(ether_setup); /** * alloc_etherdev - Allocates and sets up an Ethernet device * @sizeof_priv: Size of additional driver-private structure to be allocated * for this Ethernet device * * Fill in the fields of the device structure with Ethernet-generic * values. Basically does everything except registering the device. * * Constructs a new net device, complete with a private data area of * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for * this private data area. */ struct net_device *alloc_etherdev(int sizeof_priv) { return alloc_netdev(sizeof_priv, "eth%d", ether_setup); } EXPORT_SYMBOL(alloc_etherdev);