ipcp.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

		  (cishort == IPCP_VJ_COMP_OLD && cilen == CILEN_COMPRESS))) {
		orc = CONFREJ;
		break;
	    }

	    ho->neg_vj = 1;
	    ho->vj_protocol = cishort;
	    if (cilen == CILEN_VJ) {
		GETCHAR(maxslotindex, p);
		if (maxslotindex > ao->maxslotindex) { 
		    orc = CONFNAK;
		    if (!reject_if_disagree){
			DECPTR(1, p);
			PUTCHAR(ao->maxslotindex, p);
		    }
		}
		GETCHAR(cflag, p);
		if (cflag && !ao->cflag) {
		    orc = CONFNAK;
		    if (!reject_if_disagree){
			DECPTR(1, p);
			PUTCHAR(wo->cflag, p);
		    }
		}
		ho->maxslotindex = maxslotindex;
		ho->cflag = cflag;
	    } else {
		ho->old_vj = 1;
		ho->maxslotindex = MAX_STATES - 1;
		ho->cflag = 1;
	    }
	    break;

	default:
	    orc = CONFREJ;
	    break;
	}
endswitch:
	if (orc == CONFACK &&		/* Good CI */
	    rc != CONFACK)		/*  but prior CI wasnt? */
	    continue;			/* Don't send this one */

	if (orc == CONFNAK) {		/* Nak this CI? */
	    if (reject_if_disagree)	/* Getting fed up with sending NAKs? */
		orc = CONFREJ;		/* Get tough if so */
	    else {
		if (rc == CONFREJ)	/* Rejecting prior CI? */
		    continue;		/* Don't send this one */
		if (rc == CONFACK) {	/* Ack'd all prior CIs? */
		    rc = CONFNAK;	/* Not anymore... */
		    ucp = inp;		/* Backup */
		}
	    }
	}

	if (orc == CONFREJ &&		/* Reject this CI */
	    rc != CONFREJ) {		/*  but no prior ones? */
	    rc = CONFREJ;
	    ucp = inp;			/* Backup */
	}

	/* Need to move CI? */
	if (ucp != cip)
	    BCOPY(cip, ucp, cilen);	/* Move it */

	/* Update output pointer */
	INCPTR(cilen, ucp);
    }

    /*
     * If we aren't rejecting this packet, and we want to negotiate
     * their address, and they didn't send their address, then we
     * send a NAK with a CI_ADDR option appended.  We assume the
     * input buffer is long enough that we can append the extra
     * option safely.
     */
    if (rc != CONFREJ && !ho->neg_addr &&
	wo->req_addr && !reject_if_disagree) {
	if (rc == CONFACK) {
	    rc = CONFNAK;
	    ucp = inp;			/* reset pointer */
	    wo->req_addr = 0;		/* don't ask again */
	}
	PUTCHAR(CI_ADDR, ucp);
	PUTCHAR(CILEN_ADDR, ucp);
	tl = ntohl(wo->hisaddr);
	PUTLONG(tl, ucp);
    }

    *len = ucp - inp;			/* Compute output length */
    IPCPDEBUG(("ipcp: returning Configure-%s", CODENAME(rc)));
    return (rc);			/* Return final code */
}


/*
 * ip_check_options - check that any IP-related options are OK,
 * and assign appropriate defaults.
 */
static void
ip_check_options()
{
    struct hostent *hp;
    u_int32_t local;
    ipcp_options *wo = &ipcp_wantoptions[0];

    /*
     * Default our local IP address based on our hostname.
     * If local IP address already given, don't bother.
     */
    if (wo->ouraddr == 0) {
	/*
	 * Look up our hostname (possibly with domain name appended)
	 * and take the first IP address as our local IP address.
	 * If there isn't an IP address for our hostname, too bad.
	 */
	wo->accept_local = 1;	/* don't insist on this default value */
	if ((hp = gethostbyname(hostname)) != NULL) {
	    local = *(u_int32_t *)hp->h_addr;
	    if (local != 0 && !bad_ip_adrs(local))
		wo->ouraddr = local;
	}
    }
}


/*
 * ip_demand_conf - configure the interface as though
 * IPCP were up, for use with dial-on-demand.
 */
static int
ip_demand_conf(u)
    int u;
{
    ipcp_options *wo = &ipcp_wantoptions[u];

    if (wo->hisaddr == 0) {
	/* make up an arbitrary address for the peer */
	wo->hisaddr = htonl(0x0a707070 + pppifunit);
	wo->accept_remote = 1;
    }
    if (wo->ouraddr == 0) {
	/* make up an arbitrary address for us */
	wo->ouraddr = htonl(0x0a404040 + pppifunit);
	wo->accept_local = 1;
	disable_defaultip = 1;	/* don't tell the peer this address */
    }
    if (!sifaddr(u, wo->ouraddr, wo->hisaddr, GetMask(wo->ouraddr)))
	return 0;
    if (!sifup(u))
	return 0;
    if (!sifnpmode(u, PPP_IP, NPMODE_QUEUE))
	return 0;
    if (wo->default_route)
	if (sifdefaultroute(u, wo->ouraddr, wo->hisaddr))
	    default_route_set[u] = 1;
    if (wo->proxy_arp)
	if (sifproxyarp(u, wo->hisaddr))
	    proxy_arp_set[u] = 1;

    notice("local  IP address %I", wo->ouraddr);
    notice("remote IP address %I", wo->hisaddr);

    return 1;
}


/*
 * ipcp_up - IPCP has come UP.
 *
 * Configure the IP network interface appropriately and bring it up.
 */
static void
ipcp_up(f)
    fsm *f;
{
    u_int32_t mask;
    ipcp_options *ho = &ipcp_hisoptions[f->unit];
    ipcp_options *go = &ipcp_gotoptions[f->unit];
    ipcp_options *wo = &ipcp_wantoptions[f->unit];

    IPCPDEBUG(("ipcp: up"));

    /*
     * We must have a non-zero IP address for both ends of the link.
     */
    if (!ho->neg_addr)
	ho->hisaddr = wo->hisaddr;

    if (ho->hisaddr == 0) {
	error("Could not determine remote IP address");
	ipcp_close(f->unit, "Could not determine remote IP address");
	return;
    }
    if (go->ouraddr == 0) {
	error("Could not determine local IP address");
	ipcp_close(f->unit, "Could not determine local IP address");
	return;
    }

    if (usepeerdns && (go->dnsaddr[0] || go->dnsaddr[1])) {
	create_resolv(go->dnsaddr[0], go->dnsaddr[1]);
    }

    /*
     * Check that the peer is allowed to use the IP address it wants.
     */
    if (!auth_ip_addr(f->unit, ho->hisaddr)) {
	error("Peer is not authorized to use remote address %I", ho->hisaddr);
	ipcp_close(f->unit, "Unauthorized remote IP address");
	return;
    }

    /* set tcp compression */
    sifvjcomp(f->unit, ho->neg_vj, ho->cflag, ho->maxslotindex);

    /*
     * If we are doing dial-on-demand, the interface is already
     * configured, so we put out any saved-up packets, then set the
     * interface to pass IP packets.
     */
    if (demand) {
	if (go->ouraddr != wo->ouraddr || ho->hisaddr != wo->hisaddr) {
	    ipcp_clear_addrs(f->unit, wo->ouraddr, wo->hisaddr);
	    if (go->ouraddr != wo->ouraddr) {
		warn("Local IP address changed to %I", go->ouraddr);
		wo->ouraddr = go->ouraddr;
	    }
	    if (ho->hisaddr != wo->hisaddr) {
		warn("Remote IP address changed to %I", ho->hisaddr);
		wo->hisaddr = ho->hisaddr;
	    }

	    /* Set the interface to the new addresses */
	    mask = GetMask(go->ouraddr);
	    if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask)) {
		if (debug)
		    warn("Interface configuration failed");
		ipcp_close(f->unit, "Interface configuration failed");
		return;
	    }

	    /* assign a default route through the interface if required */
	    if (ipcp_wantoptions[f->unit].default_route) 
		if (sifdefaultroute(f->unit, go->ouraddr, ho->hisaddr))
		    default_route_set[f->unit] = 1;

	    /* Make a proxy ARP entry if requested. */
	    if (ipcp_wantoptions[f->unit].proxy_arp)
		if (sifproxyarp(f->unit, ho->hisaddr))
		    proxy_arp_set[f->unit] = 1;

	}
	demand_rexmit(PPP_IP);
	sifnpmode(f->unit, PPP_IP, NPMODE_PASS);

    } else {
	/*
	 * Set IP addresses and (if specified) netmask.
	 */
	mask = GetMask(go->ouraddr);

#if !(defined(SVR4) && (defined(SNI) || defined(__USLC__)))
	if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask)) {
	    if (debug)
		warn("Interface configuration failed");
	    ipcp_close(f->unit, "Interface configuration failed");
	    return;
	}
#endif

	/* bring the interface up for IP */
	if (!sifup(f->unit)) {
	    if (debug)
		warn("Interface failed to come up");
	    ipcp_close(f->unit, "Interface configuration failed");
	    return;
	}

#if (defined(SVR4) && (defined(SNI) || defined(__USLC__)))
	if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask)) {
	    if (debug)
		warn("Interface configuration failed");
	    ipcp_close(f->unit, "Interface configuration failed");
	    return;
	}
#endif
	sifnpmode(f->unit, PPP_IP, NPMODE_PASS);

	/* assign a default route through the interface if required */
	if (ipcp_wantoptions[f->unit].default_route) 
	    if (sifdefaultroute(f->unit, go->ouraddr, ho->hisaddr))
		default_route_set[f->unit] = 1;

	/* Make a proxy ARP entry if requested. */
	if (ipcp_wantoptions[f->unit].proxy_arp)
	    if (sifproxyarp(f->unit, ho->hisaddr))
		proxy_arp_set[f->unit] = 1;

	ipcp_wantoptions[0].ouraddr = go->ouraddr;

	notice("local  IP address %I", go->ouraddr);
	notice("remote IP address %I", ho->hisaddr);
	if (go->dnsaddr[0])
	    notice("primary   DNS address %I", go->dnsaddr[0]);
	if (go->dnsaddr[1])
	    notice("secondary DNS address %I", go->dnsaddr[1]);
    }

    np_up(f->unit, PPP_IP);
    ipcp_is_up = 1;

    if (ip_up_hook)
	ip_up_hook();
}


/*
 * ipcp_down - IPCP has gone DOWN.
 *
 * Take the IP network interface down, clear its addresses
 * and delete routes through it.
 */
static void
ipcp_down(f)
    fsm *f;
{
    IPCPDEBUG(("ipcp: down"));
    /* XXX a bit IPv4-centric here, we only need to get the stats
     * before the interface is marked down. */
    update_link_stats(f->unit);
    if (ip_down_hook)
	ip_down_hook();
    if (ipcp_is_up) {
	ipcp_is_up = 0;
	np_down(f->unit, PPP_IP);
    }
    sifvjcomp(f->unit, 0, 0, 0);

    /*
     * If we are doing dial-on-demand, set the interface
     * to queue up outgoing packets (for now).
     */
    if (demand) {
	sifnpmode(f->unit, PPP_IP, NPMODE_QUEUE);
    } else {
	sifnpmode(f->unit, PPP_IP, NPMODE_DROP);
	sifdown(f->unit);
	ipcp_clear_addrs(f->unit, ipcp_gotoptions[f->unit].ouraddr,
			 ipcp_hisoptions[f->unit].hisaddr);
    }
}


/*
 * ipcp_clear_addrs() - clear the interface addresses, routes,
 * proxy arp entries, etc.
 */
static void
ipcp_clear_addrs(unit, ouraddr, hisaddr)
    int unit;
    u_int32_t ouraddr;  /* local address */
    u_int32_t hisaddr;  /* remote address */
{
    if (proxy_arp_set[unit]) {
	cifproxyarp(unit, hisaddr);
	proxy_arp_set[unit] = 0;
    }
    if (default_route_set[unit]) {
	cifdefaultroute(unit, ouraddr, hisaddr);
	default_route_set[unit] = 0;
    }
    cifaddr(unit, ouraddr, hisaddr);
}


/*
 * ipcp_finished - possibly shut down the lower layers.
 */
static void
ipcp_finished(f)
    fsm *f;
{
    np_finished(f->unit, PPP_IP);
}

/*
 * create_resolv - create the replacement resolv.conf file
 */
static void
create_resolv(peerdns1, peerdns2)
    u_int32_t peerdns1, peerdns2;
{
  extern int              rtems_bsdnet_nameserver_count;
  extern struct in_addr   rtems_bsdnet_nameserver[];

  /* initialize values */
  rtems_bsdnet_nameserver_count = (int)0;

  /* check to see if primary was specified */
  if ( peerdns1 ) {
    rtems_bsdnet_nameserver[rtems_bsdnet_nameserver_count].s_addr = peerdns1;
    rtems_bsdnet_nameserver_count++;
  }

  /* check to see if secondary was specified */
  if ( peerdns2 ) {
    rtems_bsdnet_nameserver[rtems_bsdnet_nameserver_count].s_addr = peerdns2;
    rtems_bsdnet_nameserver_count++;
  }

  /* initialize resolver */
  __res_init();
}

/*
 * ipcp_printpkt - print the contents of an IPCP packet.
 */
static char *ipcp_codenames[] = {
    "ConfReq", "ConfAck", "ConfNak", "ConfRej",
    "TermReq", "TermAck", "CodeRej"
};

static int
ipcp_printpkt(p, plen, printer, arg)
    u_char *p;
    int plen;
    void (*printer) __P((void *, char *, ...));
    void *arg;
{
    int code, id, len, olen;
    u_char *pstart, *optend;
    u_short cishort;
    u_int32_t cilong;

    if (plen < HEADERLEN)
	return 0;
    pstart = p;
    GETCHAR(code, p);
    GETCHAR(id, p);
    GETSHORT(len, p);
    if (len < HEADERLEN || len > plen)
	return 0;

    if (code >= 1 && code <= sizeof(ipcp_codenames) / sizeof(char *))
	printer(arg, " %s", ipcp_codenames[code-1]);
    else
	printer(arg, " code=0x%x", code);
    printer(arg, " id=0x%x", id);
    len -= HEADERLEN;
    switch (code) {
    case CONFREQ:
    case CONFACK:
    case CONFNAK:
    case CONFREJ:
	/* print option list */
	while (len >= 2) {
	    GETCHAR(code, p);
	    GETCHAR(olen, p);
	    p -= 2;
	    if (olen < 2 || olen > len) {
		break;
	    }
	    printer(arg, " <");
	    len -= olen;
	    optend = p + olen;
	    switch (code) {
	    case CI_ADDRS:
		if (olen == CILEN_ADDRS) {
		    p += 2;
		    GETLONG(cilong, p);
		    printer(arg, "addrs %I", htonl(cilong));
		    GETLONG(cilong, p);
		    printer(arg, " %I", htonl(cilong));
		}
		break;
	    case CI_COMPRESSTYPE:
		if (olen >= CILEN_COMPRESS) {
		    p += 2;
		    GETSHORT(cishort, p);
		    printer(arg, "compress ");
		    switch (cishort) {
		    case IPCP_VJ_COMP:
			printer(arg, "VJ");
			break;
		    case IPCP_VJ_COMP_OLD:
			printer(arg, "old-VJ");
			break;
		    default:
			printer(arg, "0x%x", cishort);
		    }
		}
		break;
	    case CI_ADDR:
		if (olen == CILEN_ADDR) {
		    p += 2;
		    GETLONG(cilong, p);
		    printer(arg, "addr %I", htonl(cilong));
		}
		break;
	    case CI_MS_DNS1:
	    case CI_MS_DNS2:
	        p += 2;
		GETLONG(cilong, p);
		printer(arg, "ms-dns%d %I", code - CI_MS_DNS1 + 1,
			htonl(cilong));
		break;
	    case CI_MS_WINS1:
	    case CI_MS_WINS2:
	        p += 2;
		GETLONG(cilong, p);
		printer(arg, "ms-wins %I", htonl(cilong));
		break;
	    }
	    while (p < optend) {
		GETCHAR(code, p);
		printer(arg, " %.2x", code);
	    }
	    printer(arg, ">");
	}
	break;

    case TERMACK:
    case TERMREQ:
	if (len > 0 && *p >= ' ' && *p < 0x7f) {
	    printer(arg, " ");
	    print_string(p, len, printer, arg);
	    p += len;
	    len = 0;
	}
	break;
    }

    /* print the rest of the bytes in the packet */
    for (; len > 0; --len) {
	GETCHAR(code, p);
	printer(arg, " %.2x", code);
    }

    return p - pstart;
}

/*
 * ip_active_pkt - see if this IP packet is worth bringing the link up for.
 * We don't bring the link up for IP fragments or for TCP FIN packets
 * with no data.
 */
#define IP_HDRLEN	20	/* bytes */
#define IP_OFFMASK	0x1fff
#define IPPROTO_TCP	6
#define TCP_HDRLEN	20
#define TH_FIN		0x01

/*
 * We use these macros because the IP header may be at an odd address,
 * and some compilers might use word loads to get th_off or ip_hl.
 */

#define net_short(x)	(((x)[0] << 8) + (x)[1])
#define get_iphl(x)	(((unsigned char *)(x))[0] & 0xF)
#define get_ipoff(x)	net_short((unsigned char *)(x) + 6)
#define get_ipproto(x)	(((unsigned char *)(x))[9])
#define get_tcpoff(x)	(((unsigned char *)(x))[12] >> 4)
#define get_tcpflags(x)	(((unsigned char *)(x))[13])

static int
ip_active_pkt(pkt, len)
    u_char *pkt;
    int len;
{
    u_char *tcp;
    int hlen;

    len -= PPP_HDRLEN;
    pkt += PPP_HDRLEN;
    if (len < IP_HDRLEN)
	return 0;
    if ((get_ipoff(pkt) & IP_OFFMASK) != 0)
	return 0;
    if (get_ipproto(pkt) != IPPROTO_TCP)
	return 1;
    hlen = get_iphl(pkt) * 4;
    if (len < hlen + TCP_HDRLEN)
	return 0;
    tcp = pkt + hlen;
    if ((get_tcpflags(tcp) & TH_FIN) != 0 && len == hlen + get_tcpoff(tcp) * 4)
	return 0;
    return 1;
}