From a81cd86c8d93236ffccfbee44b5818ba21523463 Mon Sep 17 00:00:00 2001 From: "Michael I. Bushnell" Date: Wed, 12 Jul 1995 15:42:50 +0000 Subject: entered into RCS --- pfinet/linux-inet/rarp.c | 491 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 491 insertions(+) create mode 100644 pfinet/linux-inet/rarp.c (limited to 'pfinet/linux-inet/rarp.c') diff --git a/pfinet/linux-inet/rarp.c b/pfinet/linux-inet/rarp.c new file mode 100644 index 00000000..72924bb2 --- /dev/null +++ b/pfinet/linux-inet/rarp.c @@ -0,0 +1,491 @@ +/* linux/net/inet/rarp.c + * + * Copyright (C) 1994 by Ross Martin + * Based on linux/net/inet/arp.c, Copyright (C) 1994 by Florian La Roche + * + * This module implements the Reverse Address Resolution Protocol + * (RARP, RFC 903), which is used to convert low level addresses such + * as ethernet addresses into high level addresses such as IP addresses. + * The most common use of RARP is as a means for a diskless workstation + * to discover its IP address during a network boot. + * + ** + *** WARNING:::::::::::::::::::::::::::::::::WARNING + **** + ***** SUN machines seem determined to boot solely from the person who + **** answered their RARP query. NEVER add a SUN to your RARP table + *** unless you have all the rest to boot the box from it. + ** + * + * Currently, only ethernet address -> IP address is likely to work. + * (Is RARP ever used for anything else?) + * + * This code 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 "ip.h" +#include "route.h" +#include "protocol.h" +#include "tcp.h" +#include +#include "sock.h" +#include "arp.h" +#include "rarp.h" +#ifdef CONFIG_AX25 +#include "ax25.h" +#endif + +#ifdef CONFIG_INET_RARP + +/* + * This structure defines the RARP mapping cache. As long as we make + * changes in this structure, we keep interrupts off. + */ + +struct rarp_table +{ + struct rarp_table *next; /* Linked entry list */ + unsigned long ip; /* ip address of entry */ + unsigned char ha[MAX_ADDR_LEN]; /* Hardware address */ + unsigned char hlen; /* Length of hardware address */ + unsigned char htype; /* Type of hardware in use */ + struct device *dev; /* Device the entry is tied to */ +}; + +struct rarp_table *rarp_tables = NULL; + + +static struct packet_type rarp_packet_type = +{ + 0, /* Should be: __constant_htons(ETH_P_RARP) - but this _doesn't_ come out constant! */ + 0, /* copy */ + rarp_rcv, + NULL, + NULL +}; + +static initflag = 1; + +/* + * Called once when data first added to rarp cache with ioctl. + */ + +static void rarp_init (void) +{ + /* Register the packet type */ + rarp_packet_type.type=htons(ETH_P_RARP); + dev_add_pack(&rarp_packet_type); +} + +/* + * Release the memory for this entry. + */ + +static inline void rarp_release_entry(struct rarp_table *entry) +{ + kfree_s(entry, sizeof(struct rarp_table)); + return; +} + +/* + * Delete a RARP mapping entry in the cache. + */ + +static void rarp_destroy(unsigned long ip_addr) +{ + struct rarp_table *entry; + struct rarp_table **pentry; + + cli(); + pentry = &rarp_tables; + while ((entry = *pentry) != NULL) + { + if (entry->ip == ip_addr) + { + *pentry = entry->next; + sti(); + rarp_release_entry(entry); + return; + } + pentry = &entry->next; + } + sti(); +} + + +/* + * Receive an arp request by the device layer. Maybe it should be + * rewritten to use the incoming packet for the reply. The current + * "overhead" time isn't that high... + */ + +int rarp_rcv(struct sk_buff *skb, struct device *dev, struct packet_type *pt) +{ +/* + * We shouldn't use this type conversion. Check later. + */ + struct arphdr *rarp = (struct arphdr *)skb->h.raw; + unsigned char *rarp_ptr = (unsigned char *)(rarp+1); + struct rarp_table *entry; + long sip,tip; + unsigned char *sha,*tha; /* s for "source", t for "target" */ + +/* + * If this test doesn't pass, it's not IP, or we should ignore it anyway + */ + + if (rarp->ar_hln != dev->addr_len || dev->type != ntohs(rarp->ar_hrd) + || dev->flags&IFF_NOARP) + { + kfree_skb(skb, FREE_READ); + return 0; + } + +/* + * If it's not a RARP request, delete it. + */ + if (rarp->ar_op != htons(ARPOP_RREQUEST)) + { + kfree_skb(skb, FREE_READ); + return 0; + } + +/* + * For now we will only deal with IP addresses. + */ + + if ( +#ifdef CONFIG_AX25 + (rarp->ar_pro != htons(AX25_P_IP) && dev->type == ARPHRD_AX25) || +#endif + (rarp->ar_pro != htons(ETH_P_IP) && dev->type != ARPHRD_AX25) + || rarp->ar_pln != 4) + { + /* + * This packet is not for us. Remove it. + */ + kfree_skb(skb, FREE_READ); + return 0; +} + +/* + * Extract variable width fields + */ + + sha=rarp_ptr; + rarp_ptr+=dev->addr_len; + memcpy(&sip,rarp_ptr,4); + rarp_ptr+=4; + tha=rarp_ptr; + rarp_ptr+=dev->addr_len; + memcpy(&tip,rarp_ptr,4); + +/* + * Process entry. Use tha for table lookup according to RFC903. + */ + + cli(); + for (entry = rarp_tables; entry != NULL; entry = entry->next) + if (!memcmp(entry->ha, tha, rarp->ar_hln)) + break; + + if (entry != NULL) + { + sip=entry->ip; + sti(); + + arp_send(ARPOP_RREPLY, ETH_P_RARP, sip, dev, dev->pa_addr, sha, + dev->dev_addr); + } + else + sti(); + + kfree_skb(skb, FREE_READ); + return 0; +} + + +/* + * Set (create) a RARP cache entry. + */ + +static int rarp_req_set(struct arpreq *req) +{ + struct arpreq r; + struct rarp_table *entry; + struct sockaddr_in *si; + int htype, hlen; + unsigned long ip; + struct rtable *rt; + + memcpy_fromfs(&r, req, sizeof(r)); + + /* + * We only understand about IP addresses... + */ + + if (r.arp_pa.sa_family != AF_INET) + return -EPFNOSUPPORT; + + switch (r.arp_ha.sa_family) + { + case ARPHRD_ETHER: + htype = ARPHRD_ETHER; + hlen = ETH_ALEN; + break; +#ifdef CONFIG_AX25 + case ARPHRD_AX25: + htype = ARPHRD_AX25; + hlen = 7; + break; +#endif + default: + return -EPFNOSUPPORT; + } + + si = (struct sockaddr_in *) &r.arp_pa; + ip = si->sin_addr.s_addr; + if (ip == 0) + { + printk("RARP: SETRARP: requested PA is 0.0.0.0 !\n"); + return -EINVAL; + } + +/* + * Is it reachable directly ? + */ + + rt = ip_rt_route(ip, NULL, NULL); + if (rt == NULL) + return -ENETUNREACH; + +/* + * Is there an existing entry for this address? Find out... + */ + + cli(); + for (entry = rarp_tables; entry != NULL; entry = entry->next) + if (entry->ip == ip) + break; + +/* + * If no entry was found, create a new one. + */ + + if (entry == NULL) + { + entry = (struct rarp_table *) kmalloc(sizeof(struct rarp_table), + GFP_ATOMIC); + if (entry == NULL) + { + sti(); + return -ENOMEM; + } + if(initflag) + { + rarp_init(); + initflag=0; + } + + entry->next = rarp_tables; + rarp_tables = entry; + } + + entry->ip = ip; + entry->hlen = hlen; + entry->htype = htype; + memcpy(&entry->ha, &r.arp_ha.sa_data, hlen); + entry->dev = rt->rt_dev; + + sti(); + + return 0; +} + + +/* + * Get a RARP cache entry. + */ + +static int rarp_req_get(struct arpreq *req) +{ + struct arpreq r; + struct rarp_table *entry; + struct sockaddr_in *si; + unsigned long ip; + +/* + * We only understand about IP addresses... + */ + + memcpy_fromfs(&r, req, sizeof(r)); + + if (r.arp_pa.sa_family != AF_INET) + return -EPFNOSUPPORT; + +/* + * Is there an existing entry for this address? + */ + + si = (struct sockaddr_in *) &r.arp_pa; + ip = si->sin_addr.s_addr; + + cli(); + for (entry = rarp_tables; entry != NULL; entry = entry->next) + if (entry->ip == ip) + break; + + if (entry == NULL) + { + sti(); + return -ENXIO; + } + +/* + * We found it; copy into structure. + */ + + memcpy(r.arp_ha.sa_data, &entry->ha, entry->hlen); + r.arp_ha.sa_family = entry->htype; + sti(); + +/* + * Copy the information back + */ + + memcpy_tofs(req, &r, sizeof(r)); + return 0; +} + + +/* + * Handle a RARP layer I/O control request. + */ + +int rarp_ioctl(unsigned int cmd, void *arg) +{ + struct arpreq r; + struct sockaddr_in *si; + int err; + + switch(cmd) + { + case SIOCDRARP: + if (!suser()) + return -EPERM; + err = verify_area(VERIFY_READ, arg, sizeof(struct arpreq)); + if(err) + return err; + memcpy_fromfs(&r, arg, sizeof(r)); + if (r.arp_pa.sa_family != AF_INET) + return -EPFNOSUPPORT; + si = (struct sockaddr_in *) &r.arp_pa; + rarp_destroy(si->sin_addr.s_addr); + return 0; + + case SIOCGRARP: + err = verify_area(VERIFY_WRITE, arg, sizeof(struct arpreq)); + if(err) + return err; + return rarp_req_get((struct arpreq *)arg); + case SIOCSRARP: + if (!suser()) + return -EPERM; + err = verify_area(VERIFY_READ, arg, sizeof(struct arpreq)); + if(err) + return err; + return rarp_req_set((struct arpreq *)arg); + default: + return -EINVAL; + } + + /*NOTREACHED*/ + return 0; +} + +int rarp_get_info(char *buffer, char **start, off_t offset, int length) +{ + int len=0; + off_t begin=0; + off_t pos=0; + int size; + struct rarp_table *entry; + char ipbuffer[20]; + unsigned long netip; + if(initflag) + { + size = sprintf(buffer,"RARP disabled until entries added to cache.\n"); + pos+=size; + len+=size; + } + else + { + size = sprintf(buffer, + "IP address HW type HW address\n"); + pos+=size; + len+=size; + + cli(); + for(entry=rarp_tables; entry!=NULL; entry=entry->next) + { + netip=htonl(entry->ip); /* switch to network order */ + sprintf(ipbuffer,"%d.%d.%d.%d", + (unsigned int)(netip>>24)&255, + (unsigned int)(netip>>16)&255, + (unsigned int)(netip>>8)&255, + (unsigned int)(netip)&255); + + size = sprintf(buffer+len, + "%-17s%-20s%02x:%02x:%02x:%02x:%02x:%02x\n", + ipbuffer, + "10Mbps Ethernet", + (unsigned int)entry->ha[0], + (unsigned int)entry->ha[1], + (unsigned int)entry->ha[2], + (unsigned int)entry->ha[3], + (unsigned int)entry->ha[4], + (unsigned int)entry->ha[5]); + + len+=size; + pos=begin+len; + + if(posoffset+length) + break; + } + sti(); + } + + *start=buffer+(offset-begin); /* Start of wanted data */ + len-=(offset-begin); /* Start slop */ + if(len>length) + len=length; /* Ending slop */ + return len; +} + +#endif -- cgit v1.2.3