/* * 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. * * 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 #include __initfunc(void eth_setup(char *str, int *ints)) { struct device *d = dev_base; if (!str || !*str) return; while (d) { if (!strcmp(str,d->name)) { if (ints[0] > 0) d->irq=ints[1]; if (ints[0] > 1) d->base_addr=ints[2]; if (ints[0] > 2) d->mem_start=ints[3]; if (ints[0] > 3) d->mem_end=ints[4]; break; } d=d->next; } } /* * Create the Ethernet MAC header for an arbitrary protocol layer * * saddr=NULL means use device source address * daddr=NULL means leave destination address (eg unresolved arp) */ int eth_header(struct sk_buff *skb, struct device *dev, unsigned short type, void *daddr, void *saddr, unsigned len) { struct ethhdr *eth = (struct ethhdr *)skb_push(skb,ETH_HLEN); /* * 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. */ if(type!=ETH_P_802_3) eth->h_proto = htons(type); else eth->h_proto = htons(len); /* * Set the source hardware address. */ if(saddr) memcpy(eth->h_source,saddr,dev->addr_len); else memcpy(eth->h_source,dev->dev_addr,dev->addr_len); /* * 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(dev->hard_header_len); } if(daddr) { memcpy(eth->h_dest,daddr,dev->addr_len); return dev->hard_header_len; } return -dev->hard_header_len; } /* * Rebuild the Ethernet MAC header. This is called after an ARP * (or in future other address resolution) has completed on this * sk_buff. We now let 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 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; } /* * Determine the packet's protocol ID. 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. */ unsigned short eth_type_trans(struct sk_buff *skb, struct device *dev) { struct ethhdr *eth; unsigned char *rawp; skb->mac.raw=skb->data; skb_pull(skb,dev->hard_header_len); eth= skb->mac.ethernet; if(*eth->h_dest&1) { if(memcmp(eth->h_dest,dev->broadcast, ETH_ALEN)==0) 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(dev->flags&(IFF_PROMISC/*|IFF_ALLMULTI*/)) { if(memcmp(eth->h_dest,dev->dev_addr, ETH_ALEN)) 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); } int eth_header_parse(struct sk_buff *skb, unsigned char *haddr) { struct ethhdr *eth = skb->mac.ethernet; memcpy(haddr, eth->h_source, ETH_ALEN); return ETH_ALEN; } int eth_header_cache(struct neighbour *neigh, struct hh_cache *hh) { unsigned short type = hh->hh_type; struct ethhdr *eth = (struct ethhdr*)(((u8*)hh->hh_data) + 2); struct device *dev = neigh->dev; if (type == __constant_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); return 0; } /* * Called by Address Resolution module to notify changes in address. */ void eth_header_cache_update(struct hh_cache *hh, struct device *dev, unsigned char * haddr) { memcpy(((u8*)hh->hh_data) + 2, haddr, dev->addr_len); } #ifndef CONFIG_IP_ROUTER /* * Copy from an ethernet device memory space to an sk_buff while checksumming if IP */ void eth_copy_and_sum(struct sk_buff *dest, unsigned char *src, int length, int base) { struct ethhdr *eth; struct iphdr *iph; int ip_length; eth=(struct ethhdr *)src; if(eth->h_proto!=htons(ETH_P_IP)) { memcpy(dest->data,src,length); return; } /* * We have to watch for padded packets. The csum doesn't include the * padding, and there is no point in copying the padding anyway. * We have to use the smaller of length and ip_length because it * can happen that ip_length > length. */ memcpy(dest->data,src,sizeof(struct iphdr)+ETH_HLEN); /* ethernet is always >= 34 */ length -= sizeof(struct iphdr) + ETH_HLEN; iph=(struct iphdr*)(src+ETH_HLEN); ip_length = ntohs(iph->tot_len) - sizeof(struct iphdr); /* Also watch out for bogons - min IP size is 8 (rfc-1042) */ if ((ip_length <= length) && (ip_length > 7)) length=ip_length; dest->csum=csum_partial_copy(src+sizeof(struct iphdr)+ETH_HLEN,dest->data+sizeof(struct iphdr)+ETH_HLEN,length,base); dest->ip_summed=1; } #endif /* !(CONFIG_IP_ROUTER) */