if_ether.c

嵌入式操作系统ECOS的网络开发包

	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.tqh_first; ia != 0; ia = ia->ia_list.tqe_next)
		if (ia->ia_ifp == &ac->ac_if ||
		    (ia->ia_ifp->if_bridge &&
		    ia->ia_ifp->if_bridge == ac->ac_if.if_bridge)) {
			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))) {
#ifdef __ECOS
#else
		log(LOG_ERR,
		    "arp: ether address is broadcast for IP address %s!\n",
		    inet_ntoa(isaddr));
#endif
		goto out;
	}
	if (isaddr.s_addr == myaddr.s_addr) {
#ifdef __ECOS
#else
		log(LOG_ERR,
		   "duplicate IP address %s sent from ethernet address %s\n",
		   inet_ntoa(isaddr), ether_sprintf(ea->arp_sha));
#endif
		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)) {
		  	if (rt->rt_flags & RTF_PERMANENT_ARP) {
#ifdef __ECOS
#else
				log(LOG_WARNING,
				   "arp: attempt to overwrite permanent "
				   "entry for %s by %s on %s\n", 
				   inet_ntoa(isaddr),
				   ether_sprintf(ea->arp_sha),
				   (&ac->ac_if)->if_xname);
#endif
				goto out;
			} else if (rt->rt_ifp != &ac->ac_if) {
#ifdef __ECOS
#else
			        log(LOG_WARNING,
				   "arp: attempt to overwrite entry for %s "
				   "on %s by %s on %s\n",
				   inet_ntoa(isaddr), rt->rt_ifp->if_xname,
				   ether_sprintf(ea->arp_sha),
				   (&ac->ac_if)->if_xname);
#endif
				goto out;
			} else {
#ifdef __ECOS
#else
				log(LOG_INFO,
				   "arp info overwritten for %s by %s on %s\n",
			    	   inet_ntoa(isaddr), 
				   ether_sprintf(ea->arp_sha),
				   (&ac->ac_if)->if_xname);
#endif
				rt->rt_expire = 1; /* no longer static */
			}
		}
		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 == 0)
			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));
	bcopy((caddr_t)ac->ac_enaddr, (caddr_t)eh->ether_shost,
	    sizeof(eh->ether_shost));
	eh->ether_type = htons(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_int32_t addr;
	int create, proxy;
{
	register struct rtentry *rt;
	static struct sockaddr_inarp sin;

	sin.sin_len = sizeof(sin);
	sin.sin_family = AF_INET;
	sin.sin_addr.s_addr = addr;
	sin.sin_other = proxy ? SIN_PROXY : 0;
	rt = rtalloc1(sintosa(&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)
#ifdef __ECOS
#else
			log(LOG_DEBUG,
			    "arplookup: unable to enter address for %s\n",
			    inet_ntoa(sin.sin_addr));
#endif
		return (0);
	}
	return ((struct llinfo_arp *)rt->rt_llinfo);
}

int
arpioctl(cmd, data)
	u_long cmd;
	caddr_t data;
{

	return (EOPNOTSUPP);
}

void
arp_ifinit(ac, ifa)
	struct arpcom *ac;
	struct ifaddr *ifa;
{

	/* Warn the user if another station has this IP address. */
	arprequest(ac,
	    &(IA_SIN(ifa)->sin_addr.s_addr),
	    &(IA_SIN(ifa)->sin_addr.s_addr),
	    ac->ac_enaddr);
	ifa->ifa_rtrequest = arp_rtrequest;
	ifa->ifa_flags |= RTF_CLONING;
}

/*
 * Called from Ethernet interrupt handlers
 * when ether packet type ETHERTYPE_REVARP
 * is received.  Common length and type checks are done here,
 * then the protocol-specific routine is called.
 */
void
revarpinput(m)
	struct mbuf *m;
{
	struct arphdr *ar;

	if (m->m_len < sizeof(struct arphdr))
		goto out;
	ar = mtod(m, struct arphdr *);
	if (ntohs(ar->ar_hrd) != ARPHRD_ETHER)
		goto out;
	if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln))
		goto out;
	switch (ntohs(ar->ar_pro)) {

	case ETHERTYPE_IP:
	case ETHERTYPE_IPTRAILERS:
		in_revarpinput(m);
		return;

	default:
		break;
	}
out:
	m_freem(m);
}

/*
 * RARP for Internet protocols on Ethernet.
 * Algorithm is that given in RFC 903.
 * We are only using for bootstrap purposes to get an ip address for one of
 * our interfaces.  Thus we support no user-interface.
 *
 * Since the contents of the RARP reply are specific to the interface that
 * sent the request, this code must ensure that they are properly associated.
 *
 * Note: also supports ARP via RARP packets, per the RFC.
 */
void
in_revarpinput(m)
	struct mbuf *m;
{
	struct ifnet *ifp;
	struct ether_arp *ar;
	int op;

	ar = mtod(m, struct ether_arp *);
	op = ntohs(ar->arp_op);
	switch (op) {
	case ARPOP_REQUEST:
	case ARPOP_REPLY:	/* per RFC */
		in_arpinput(m);
		return;
	case ARPOP_REVREPLY:
		break;
	case ARPOP_REVREQUEST:	/* handled by rarpd(8) */
	default:
		goto out;
	}
	if (!revarp_in_progress)
		goto out;
	ifp = m->m_pkthdr.rcvif;
	if (ifp != myip_ifp) /* !same interface */
		goto out;
	if (myip_initialized)
		goto wake;
	if (bcmp(ar->arp_tha, ((struct arpcom *)ifp)->ac_enaddr,
	    sizeof(ar->arp_tha)))
		goto out;
	bcopy((caddr_t)ar->arp_spa, (caddr_t)&srv_ip, sizeof(srv_ip));
	bcopy((caddr_t)ar->arp_tpa, (caddr_t)&myip, sizeof(myip));
	myip_initialized = 1;
wake:	/* Do wakeup every time in case it was missed. */
	wakeup((caddr_t)&myip);

out:
	m_freem(m);
}

/*
 * Send a RARP request for the ip address of the specified interface.
 * The request should be RFC 903-compliant.
 */
void
revarprequest(ifp)
	struct ifnet *ifp;
{
	struct sockaddr sa;
	struct mbuf *m;
	struct ether_header *eh;
	struct ether_arp *ea;
	struct arpcom *ac = (struct arpcom *)ifp;

	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 = htons(ETHERTYPE_REVARP);
	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_REVREQUEST);
	bcopy((caddr_t)ac->ac_enaddr, (caddr_t)eh->ether_shost,
	   sizeof(ea->arp_tha));
	bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_sha,
	   sizeof(ea->arp_sha));
	bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_tha,
	   sizeof(ea->arp_tha));
	sa.sa_family = AF_UNSPEC;
	sa.sa_len = sizeof(sa);
	ifp->if_output(ifp, m, &sa, (struct rtentry *)0);
}

/*
 * RARP for the ip address of the specified interface, but also
 * save the ip address of the server that sent the answer.
 * Timeout if no response is received.
 */
int
revarpwhoarewe(ifp, serv_in, clnt_in)
	struct ifnet *ifp;
	struct in_addr *serv_in;
	struct in_addr *clnt_in;
{
	int result, count = 20;
	
	if (myip_initialized) 
		return EIO;

	myip_ifp = ifp;
	revarp_in_progress = 1;
	while (count--) {
		revarprequest(ifp);
		result = tsleep((caddr_t)&myip, PSOCK, "revarp", hz/2);
		if (result != EWOULDBLOCK)
			break;
	}
	revarp_in_progress = 0;
	if (!myip_initialized)
		return ENETUNREACH;
	
	bcopy((caddr_t)&srv_ip, serv_in, sizeof(*serv_in));
	bcopy((caddr_t)&myip, clnt_in, sizeof(*clnt_in));
	return 0;
}

/* For compatibility: only saves interface address. */
int
revarpwhoami(in, ifp)
	struct in_addr *in;
	struct ifnet *ifp;
{
	struct in_addr server;
	return (revarpwhoarewe(ifp, &server, in));
}


#ifdef DDB

#include <machine/db_machdep.h>
#include <ddb/db_interface.h>
#include <ddb/db_output.h>

static void
db_print_sa(sa)
	struct sockaddr *sa;
{
	int len;
	u_char *p;

	if (sa == 0) {
		db_printf("[NULL]");
		return;
	}

	p = (u_char*)sa;
	len = sa->sa_len;
	db_printf("[");
	while (len > 0) {
		db_printf("%d", *p);
		p++;
		len--;
		if (len)
			db_printf(",");
	}
	db_printf("]\n");
}

static void
db_print_ifa(ifa)
	struct ifaddr *ifa;
{
	if (ifa == 0)
		return;
	db_printf("  ifa_addr=");
	db_print_sa(ifa->ifa_addr);
	db_printf("  ifa_dsta=");
	db_print_sa(ifa->ifa_dstaddr);
	db_printf("  ifa_mask=");
	db_print_sa(ifa->ifa_netmask);
	db_printf("  flags=0x%x, refcnt=%d, metric=%d\n",
	    ifa->ifa_flags, ifa->ifa_refcnt, ifa->ifa_metric);
}

static void
db_print_llinfo(li)
	caddr_t li;
{
	struct llinfo_arp *la;

	if (li == 0)
		return;
	la = (struct llinfo_arp *)li;
	db_printf("  la_rt=%p la_hold=%p, la_asked=0x%lx\n",
	    la->la_rt, la->la_hold, la->la_asked);
}

/*
 * Function to pass to rn_walktree().
 * Return non-zero error to abort walk.
 */
static int
db_show_radix_node(rn, w)
	struct radix_node *rn;
	void *w;
{
	struct rtentry *rt = (struct rtentry *)rn;

	db_printf("rtentry=%p", rt);

	db_printf(" flags=0x%x refcnt=%d use=%ld expire=%ld\n",
	    rt->rt_flags, rt->rt_refcnt, rt->rt_use, rt->rt_expire);

	db_printf(" key="); db_print_sa(rt_key(rt));
	db_printf(" mask="); db_print_sa(rt_mask(rt));
	db_printf(" gw="); db_print_sa(rt->rt_gateway);

	db_printf(" ifp=%p ", rt->rt_ifp);
	if (rt->rt_ifp)
		db_printf("(%s)", rt->rt_ifp->if_xname);
	else
		db_printf("(NULL)");

	db_printf(" ifa=%p\n", rt->rt_ifa);
	db_print_ifa(rt->rt_ifa);

	db_printf(" genmask="); db_print_sa(rt->rt_genmask);

	db_printf(" gwroute=%p llinfo=%p\n", rt->rt_gwroute, rt->rt_llinfo);
	db_print_llinfo(rt->rt_llinfo);
	return (0);
}

/*
 * Function to print all the route trees.
 * Use this from ddb:  "call db_show_arptab"
 */
int
db_show_arptab()
{
	struct radix_node_head *rnh;
	rnh = rt_tables[AF_INET];
	db_printf("Route tree for AF_INET\n");
	if (rnh == NULL) {
		db_printf(" (not initialized)\n");
		return (0);
	}
	rn_walktree(rnh, db_show_radix_node, NULL);
	return (0);
}
#endif
#endif /* INET */