4.4BSD/usr/src/sys/netinet/if_ether.c
/*
* Copyright (c) 1982, 1986, 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)if_ether.c 8.1 (Berkeley) 6/10/93
*/
/*
* Ethernet address resolution protocol.
* TODO:
* add "inuse/lock" bit (or ref. count) along with valid bit
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/syslog.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h>
#define SIN(s) ((struct sockaddr_in *)s)
#define SDL(s) ((struct sockaddr_dl *)s)
#define SRP(s) ((struct sockaddr_inarp *)s)
/*
* ARP trailer negotiation. Trailer protocol is not IP specific,
* but ARP request/response use IP addresses.
*/
#define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL
/* timer values */
int arpt_prune = (5*60*1); /* walk list every 5 minutes */
int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */
int arpt_down = 20; /* once declared down, don't send for 20 secs */
#define rt_expire rt_rmx.rmx_expire
static void arprequest __P((struct arpcom *, u_long *, u_long *, u_char *));
static void arptfree __P((struct llinfo_arp *));
static void arptimer __P((void *));
static struct llinfo_arp *arplookup __P((u_long, int, int));
static void in_arpinput __P((struct mbuf *));
extern struct ifnet loif;
extern struct timeval time;
struct llinfo_arp llinfo_arp = {&llinfo_arp, &llinfo_arp};
struct ifqueue arpintrq = {0, 0, 0, 50};
int arp_inuse, arp_allocated, arp_intimer;
int arp_maxtries = 5;
int useloopback = 1; /* use loopback interface for local traffic */
int arpinit_done = 0;
/*
* Timeout routine. Age arp_tab entries periodically.
*/
/* ARGSUSED */
static void
arptimer(ignored_arg)
void *ignored_arg;
{
int s = splnet();
register struct llinfo_arp *la = llinfo_arp.la_next;
timeout(arptimer, (caddr_t)0, arpt_prune * hz);
while (la != &llinfo_arp) {
register struct rtentry *rt = la->la_rt;
la = la->la_next;
if (rt->rt_expire && rt->rt_expire <= time.tv_sec)
arptfree(la->la_prev); /* timer has expired, clear */
}
splx(s);
}
/*
* Parallel to llc_rtrequest.
*/
void
arp_rtrequest(req, rt, sa)
int req;
register struct rtentry *rt;
struct sockaddr *sa;
{
register struct sockaddr *gate = rt->rt_gateway;
register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo;
static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};
if (!arpinit_done) {
arpinit_done = 1;
timeout(arptimer, (caddr_t)0, hz);
}
if (rt->rt_flags & RTF_GATEWAY)
return;
switch (req) {
case RTM_ADD:
/*
* XXX: If this is a manually added route to interface
* such as older version of routed or gated might provide,
* restore cloning bit.
*/
if ((rt->rt_flags & RTF_HOST) == 0 &&
SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)
rt->rt_flags |= RTF_CLONING;
if (rt->rt_flags & RTF_CLONING) {
/*
* Case 1: This route should come from a route to iface.
*/
rt_setgate(rt, rt_key(rt),
(struct sockaddr *)&null_sdl);
gate = rt->rt_gateway;
SDL(gate)->sdl_type = rt->rt_ifp->if_type;
SDL(gate)->sdl_index = rt->rt_ifp->if_index;
rt->rt_expire = time.tv_sec;
break;
}
/* Announce a new entry if requested. */
if (rt->rt_flags & RTF_ANNOUNCE)
arprequest((struct arpcom *)rt->rt_ifp,
&SIN(rt_key(rt))->sin_addr.s_addr,
&SIN(rt_key(rt))->sin_addr.s_addr,
(u_char *)LLADDR(SDL(gate)));
/*FALLTHROUGH*/
case RTM_RESOLVE:
if (gate->sa_family != AF_LINK ||
gate->sa_len < sizeof(null_sdl)) {
log(LOG_DEBUG, "arp_rtrequest: bad gateway value");
break;
}
SDL(gate)->sdl_type = rt->rt_ifp->if_type;
SDL(gate)->sdl_index = rt->rt_ifp->if_index;
if (la != 0)
break; /* This happens on a route change */
/*
* Case 2: This route may come from cloning, or a manual route
* add with a LL address.
*/
R_Malloc(la, struct llinfo_arp *, sizeof(*la));
rt->rt_llinfo = (caddr_t)la;
if (la == 0) {
log(LOG_DEBUG, "arp_rtrequest: malloc failed\n");
break;
}
arp_inuse++, arp_allocated++;
Bzero(la, sizeof(*la));
la->la_rt = rt;
rt->rt_flags |= RTF_LLINFO;
insque(la, &llinfo_arp);
if (SIN(rt_key(rt))->sin_addr.s_addr ==
(IA_SIN(rt->rt_ifa))->sin_addr.s_addr) {
/*
* This test used to be
* if (loif.if_flags & IFF_UP)
* It allowed local traffic to be forced
* through the hardware by configuring the loopback down.
* However, it causes problems during network configuration
* for boards that can't receive packets they send.
* It is now necessary to clear "useloopback" and remove
* the route to force traffic out to the hardware.
*/
rt->rt_expire = 0;
Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr,
LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6);
if (useloopback)
rt->rt_ifp = &loif;
}
break;
case RTM_DELETE:
if (la == 0)
break;
arp_inuse--;
remque(la);
rt->rt_llinfo = 0;
rt->rt_flags &= ~RTF_LLINFO;
if (la->la_hold)
m_freem(la->la_hold);
Free((caddr_t)la);
}
}
/*
* Broadcast an ARP packet, asking who has addr on interface ac.
*/
void
arpwhohas(ac, addr)
register struct arpcom *ac;
register struct in_addr *addr;
{
arprequest(ac, &ac->ac_ipaddr.s_addr, &addr->s_addr, ac->ac_enaddr);
}
/*
* Broadcast an ARP request. Caller specifies:
* - arp header source ip address
* - arp header target ip address
* - arp header source ethernet address
*/
static void
arprequest(ac, sip, tip, enaddr)
register struct arpcom *ac;
register u_long *sip, *tip;
register u_char *enaddr;
{
register struct mbuf *m;
register struct ether_header *eh;
register struct ether_arp *ea;
struct sockaddr sa;
if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
return;
m->m_len = sizeof(*ea);
m->m_pkthdr.len = sizeof(*ea);
MH_ALIGN(m, sizeof(*ea));
ea = mtod(m, struct ether_arp *);
eh = (struct ether_header *)sa.sa_data;
bzero((caddr_t)ea, sizeof (*ea));
bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost,
sizeof(eh->ether_dhost));
eh->ether_type = ETHERTYPE_ARP; /* if_output will swap */
ea->arp_hrd = htons(ARPHRD_ETHER);
ea->arp_pro = htons(ETHERTYPE_IP);
ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */
ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */
ea->arp_op = htons(ARPOP_REQUEST);
bcopy((caddr_t)enaddr, (caddr_t)ea->arp_sha, sizeof(ea->arp_sha));
bcopy((caddr_t)sip, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa));
bcopy((caddr_t)tip, (caddr_t)ea->arp_tpa, sizeof(ea->arp_tpa));
sa.sa_family = AF_UNSPEC;
sa.sa_len = sizeof(sa);
(*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0);
}
/*
* Resolve an IP address into an ethernet address. If success,
* desten is filled in. If there is no entry in arptab,
* set one up and broadcast a request for the IP address.
* Hold onto this mbuf and resend it once the address
* is finally resolved. A return value of 1 indicates
* that desten has been filled in and the packet should be sent
* normally; a 0 return indicates that the packet has been
* taken over here, either now or for later transmission.
*/
int
arpresolve(ac, rt, m, dst, desten)
register struct arpcom *ac;
register struct rtentry *rt;
struct mbuf *m;
register struct sockaddr *dst;
register u_char *desten;
{
register struct llinfo_arp *la;
struct sockaddr_dl *sdl;
if (m->m_flags & M_BCAST) { /* broadcast */
bcopy((caddr_t)etherbroadcastaddr, (caddr_t)desten,
sizeof(etherbroadcastaddr));
return (1);
}
if (m->m_flags & M_MCAST) { /* multicast */
ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
return(1);
}
if (rt)
la = (struct llinfo_arp *)rt->rt_llinfo;
else {
if (la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0))
rt = la->la_rt;
}
if (la == 0 || rt == 0) {
log(LOG_DEBUG, "arpresolve: can't allocate llinfo");
m_freem(m);
return (0);
}
sdl = SDL(rt->rt_gateway);
/*
* Check the address family and length is valid, the address
* is resolved; otherwise, try to resolve.
*/
if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) &&
sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
return 1;
}
/*
* There is an arptab entry, but no ethernet address
* response yet. Replace the held mbuf with this
* latest one.
*/
if (la->la_hold)
m_freem(la->la_hold);
la->la_hold = m;
if (rt->rt_expire) {
rt->rt_flags &= ~RTF_REJECT;
if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) {
rt->rt_expire = time.tv_sec;
if (la->la_asked++ < arp_maxtries)
arpwhohas(ac, &(SIN(dst)->sin_addr));
else {
rt->rt_flags |= RTF_REJECT;
rt->rt_expire += arpt_down;
la->la_asked = 0;
}
}
}
return (0);
}
/*
* Common length and type checks are done here,
* then the protocol-specific routine is called.
*/
void
arpintr()
{
register struct mbuf *m;
register struct arphdr *ar;
int s;
while (arpintrq.ifq_head) {
s = splimp();
IF_DEQUEUE(&arpintrq, m);
splx(s);
if (m == 0 || (m->m_flags & M_PKTHDR) == 0)
panic("arpintr");
if (m->m_len >= sizeof(struct arphdr) &&
(ar = mtod(m, struct arphdr *)) &&
ntohs(ar->ar_hrd) == ARPHRD_ETHER &&
m->m_len >=
sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln)
switch (ntohs(ar->ar_pro)) {
case ETHERTYPE_IP:
case ETHERTYPE_IPTRAILERS:
in_arpinput(m);
continue;
}
m_freem(m);
}
}
/*
* ARP for Internet protocols on 10 Mb/s Ethernet.
* Algorithm is that given in RFC 826.
* In addition, a sanity check is performed on the sender
* protocol address, to catch impersonators.
* We no longer handle negotiations for use of trailer protocol:
* Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
* along with IP replies if we wanted trailers sent to us,
* and also sent them in response to IP replies.
* This allowed either end to announce the desire to receive
* trailer packets.
* We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
* but formerly didn't normally send requests.
*/
static void
in_arpinput(m)
struct mbuf *m;
{
register struct ether_arp *ea;
register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif;
struct ether_header *eh;
register struct llinfo_arp *la = 0;
register struct rtentry *rt;
struct in_ifaddr *ia, *maybe_ia = 0;
struct sockaddr_dl *sdl;
struct sockaddr sa;
struct in_addr isaddr, itaddr, myaddr;
int op;
ea = mtod(m, struct ether_arp *);
op = ntohs(ea->arp_op);
bcopy((caddr_t)ea->arp_spa, (caddr_t)&isaddr, sizeof (isaddr));
bcopy((caddr_t)ea->arp_tpa, (caddr_t)&itaddr, sizeof (itaddr));
for (ia = in_ifaddr; ia; ia = ia->ia_next)
if (ia->ia_ifp == &ac->ac_if) {
maybe_ia = ia;
if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) ||
(isaddr.s_addr == ia->ia_addr.sin_addr.s_addr))
break;
}
if (maybe_ia == 0)
goto out;
myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr;
if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr,
sizeof (ea->arp_sha)))
goto out; /* it's from me, ignore it. */
if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr,
sizeof (ea->arp_sha))) {
log(LOG_ERR,
"arp: ether address is broadcast for IP address %x!\n",
ntohl(isaddr.s_addr));
goto out;
}
if (isaddr.s_addr == myaddr.s_addr) {
log(LOG_ERR,
"duplicate IP address %x!! sent from ethernet address: %s\n",
ntohl(isaddr.s_addr), ether_sprintf(ea->arp_sha));
itaddr = myaddr;
goto reply;
}
la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0);
if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) {
if (sdl->sdl_alen &&
bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen))
log(LOG_INFO, "arp info overwritten for %x by %s\n",
isaddr.s_addr, ether_sprintf(ea->arp_sha));
bcopy((caddr_t)ea->arp_sha, LLADDR(sdl),
sdl->sdl_alen = sizeof(ea->arp_sha));
if (rt->rt_expire)
rt->rt_expire = time.tv_sec + arpt_keep;
rt->rt_flags &= ~RTF_REJECT;
la->la_asked = 0;
if (la->la_hold) {
(*ac->ac_if.if_output)(&ac->ac_if, la->la_hold,
rt_key(rt), rt);
la->la_hold = 0;
}
}
reply:
if (op != ARPOP_REQUEST) {
out:
m_freem(m);
return;
}
if (itaddr.s_addr == myaddr.s_addr) {
/* I am the target */
bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha,
sizeof(ea->arp_sha));
bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_sha,
sizeof(ea->arp_sha));
} else {
la = arplookup(itaddr.s_addr, 0, SIN_PROXY);
if (la == NULL)
goto out;
rt = la->la_rt;
bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha,
sizeof(ea->arp_sha));
sdl = SDL(rt->rt_gateway);
bcopy(LLADDR(sdl), (caddr_t)ea->arp_sha, sizeof(ea->arp_sha));
}
bcopy((caddr_t)ea->arp_spa, (caddr_t)ea->arp_tpa, sizeof(ea->arp_spa));
bcopy((caddr_t)&itaddr, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa));
ea->arp_op = htons(ARPOP_REPLY);
ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */
eh = (struct ether_header *)sa.sa_data;
bcopy((caddr_t)ea->arp_tha, (caddr_t)eh->ether_dhost,
sizeof(eh->ether_dhost));
eh->ether_type = ETHERTYPE_ARP;
sa.sa_family = AF_UNSPEC;
sa.sa_len = sizeof(sa);
(*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0);
return;
}
/*
* Free an arp entry.
*/
static void
arptfree(la)
register struct llinfo_arp *la;
{
register struct rtentry *rt = la->la_rt;
register struct sockaddr_dl *sdl;
if (rt == 0)
panic("arptfree");
if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) &&
sdl->sdl_family == AF_LINK) {
sdl->sdl_alen = 0;
la->la_asked = 0;
rt->rt_flags &= ~RTF_REJECT;
return;
}
rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt),
0, (struct rtentry **)0);
}
/*
* Lookup or enter a new address in arptab.
*/
static struct llinfo_arp *
arplookup(addr, create, proxy)
u_long addr;
int create, proxy;
{
register struct rtentry *rt;
static struct sockaddr_inarp sin = {sizeof(sin), AF_INET };
sin.sin_addr.s_addr = addr;
sin.sin_other = proxy ? SIN_PROXY : 0;
rt = rtalloc1((struct sockaddr *)&sin, create);
if (rt == 0)
return (0);
rt->rt_refcnt--;
if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 ||
rt->rt_gateway->sa_family != AF_LINK) {
if (create)
log(LOG_DEBUG, "arptnew failed on %x\n", ntohl(addr));
return (0);
}
return ((struct llinfo_arp *)rt->rt_llinfo);
}
int
arpioctl(cmd, data)
int cmd;
caddr_t data;
{
return (EOPNOTSUPP);
}