dhclient.c

ReactOS是一些高手根据Windows XP的内核编写出的类XP。内核实现机理和API函数调用几乎相同。甚至可以兼容XP的程序。喜欢研究系统内核的人可以看一看。

	/* XXX should be fixed by resetting the client state */
	if (ip->client->new->expiry < 60)
		ip->client->new->expiry = 60;

	/* Take the server-provided renewal time if there is one;
	   otherwise figure it out according to the spec. */
	if (ip->client->new->options[DHO_DHCP_RENEWAL_TIME].len)
		ip->client->new->renewal = getULong(
		    ip->client->new->options[DHO_DHCP_RENEWAL_TIME].data);
	else
		ip->client->new->renewal = ip->client->new->expiry / 2;

	/* Same deal with the rebind time. */
	if (ip->client->new->options[DHO_DHCP_REBINDING_TIME].len)
		ip->client->new->rebind = getULong(
		    ip->client->new->options[DHO_DHCP_REBINDING_TIME].data);
	else
		ip->client->new->rebind = ip->client->new->renewal +
		    ip->client->new->renewal / 2 + ip->client->new->renewal / 4;

#ifdef _REACTOS_
	ip->client->new->obtained = cur_time;
#endif
	ip->client->new->expiry += cur_time;
	/* Lease lengths can never be negative. */
	if (ip->client->new->expiry < cur_time)
		ip->client->new->expiry = TIME_MAX;
	ip->client->new->renewal += cur_time;
	if (ip->client->new->renewal < cur_time)
		ip->client->new->renewal = TIME_MAX;
	ip->client->new->rebind += cur_time;
	if (ip->client->new->rebind < cur_time)
		ip->client->new->rebind = TIME_MAX;

	bind_lease(ip);
}

void set_name_servers( struct client_lease *new_lease ) {
    if( new_lease->options[DHO_DOMAIN_NAME_SERVERS].len ) {
        HKEY RegKey;
        struct iaddr nameserver;
        char *nsbuf;
        int i, addrs =
            new_lease->options[DHO_DOMAIN_NAME_SERVERS].len / sizeof(ULONG);

               /* XXX I'm setting addrs to 1 until we are ready up the chain */
               addrs = 1;
        nsbuf = malloc( addrs * sizeof(IP_ADDRESS_STRING) );
        nsbuf[0] = 0;

        if( nsbuf && !RegOpenKeyEx
            ( HKEY_LOCAL_MACHINE,
              "SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters",
              0, KEY_WRITE, &RegKey ) ) {
            for( i = 0; i < addrs; i++ ) {
                nameserver.len = sizeof(ULONG);
                memcpy( nameserver.iabuf,
                        new_lease->options[DHO_DOMAIN_NAME_SERVERS].data +
                        (i * sizeof(ULONG)), sizeof(ULONG) );
                strcat( nsbuf, piaddr(nameserver) );
                if( i != addrs-1 ) strcat( nsbuf, "," );
            }

            DH_DbgPrint(MID_TRACE,("Setting Nameservers: %s\n", nsbuf));

            /* XXX Fixme: I think this may be wrong and that we might have
             * a problem somewhere else (in iphlpapi for example).
             *
             * Recheck the +1 below.
             */
            RegSetValueEx( RegKey, "NameServer", 0, REG_SZ,
                           (LPBYTE)nsbuf, strlen(nsbuf) + 1 );

            free( nsbuf );
        }
    }
}

void setup_adapter( PDHCP_ADAPTER Adapter, struct client_lease *new_lease ) {
    struct iaddr netmask;

    if( Adapter->NteContext )
        DeleteIPAddress( Adapter->NteContext );

    /* Set up our default router if we got one from the DHCP server */
    if( new_lease->options[DHO_SUBNET_MASK].len ) {
        NTSTATUS Status;

        memcpy( netmask.iabuf,
                new_lease->options[DHO_SUBNET_MASK].data,
                new_lease->options[DHO_SUBNET_MASK].len );

        Status = AddIPAddress
            ( *((ULONG*)new_lease->address.iabuf),
              *((ULONG*)netmask.iabuf),
              Adapter->IfMib.dwIndex,
              &Adapter->NteContext,
              &Adapter->NteInstance );

        if( !NT_SUCCESS(Status) )
            warning("AddIPAddress: %lx\n", Status);
    }

    if( new_lease->options[DHO_ROUTERS].len ) {
        MIB_IPFORWARDROW RouterMib;
        NTSTATUS Status;

        RouterMib.dwForwardDest = 0; /* Default route */
        RouterMib.dwForwardMask = 0;
        RouterMib.dwForwardMetric1 = 1;

        if( old_default_route ) {
            /* If we set a default route before, delete it before continuing */
            RouterMib.dwForwardDest = old_default_route;
            DeleteIpForwardEntry( &RouterMib );
        }

        RouterMib.dwForwardNextHop =
            *((ULONG*)new_lease->options[DHO_ROUTERS].data);

        Status = CreateIpForwardEntry( &RouterMib );

        if( !NT_SUCCESS(Status) )
            warning("CreateIpForwardEntry: %lx\n", Status);
        else
            old_default_route = RouterMib.dwForwardNextHop;
    }
}


void
bind_lease(struct interface_info *ip)
{
    PDHCP_ADAPTER Adapter;
    struct client_lease *new_lease = ip->client->new;

    /* Remember the medium. */
    ip->client->new->medium = ip->client->medium;
    ip->client->active = ip->client->new;
    ip->client->new = NULL;

    /* Set up a timeout to start the renewal process. */
    /* Timeout of zero means no timeout (some implementations seem to use
     * one day).
     */
    if( ip->client->active->renewal - cur_time )
        add_timeout(ip->client->active->renewal, state_bound, ip);

    note("bound to %s -- renewal in %ld seconds.",
         piaddr(ip->client->active->address),
         ip->client->active->renewal - cur_time);

    ip->client->state = S_BOUND;

    Adapter = AdapterFindInfo( ip );

    if( Adapter )  setup_adapter( Adapter, new_lease );
    else warning("Could not find adapter for info %p\n", ip);

    set_name_servers( new_lease );

    reinitialize_interfaces();
}

/*
 * state_bound is called when we've successfully bound to a particular
 * lease, but the renewal time on that lease has expired.   We are
 * expected to unicast a DHCPREQUEST to the server that gave us our
 * original lease.
 */
void
state_bound(void *ipp)
{
	struct interface_info *ip = ipp;

	ASSERT_STATE(state, S_BOUND);

	/* T1 has expired. */
	make_request(ip, ip->client->active);
	ip->client->xid = ip->client->packet.xid;

	if (ip->client->active->options[DHO_DHCP_SERVER_IDENTIFIER].len == 4) {
		memcpy(ip->client->destination.iabuf, ip->client->active->
		    options[DHO_DHCP_SERVER_IDENTIFIER].data, 4);
		ip->client->destination.len = 4;
	} else
		ip->client->destination = iaddr_broadcast;

	ip->client->first_sending = cur_time;
	ip->client->interval = ip->client->config->initial_interval;
	ip->client->state = S_RENEWING;

	/* Send the first packet immediately. */
	send_request(ip);
}

void
bootp(struct packet *packet)
{
	struct iaddrlist *ap;

	if (packet->raw->op != BOOTREPLY)
		return;

	/* If there's a reject list, make sure this packet's sender isn't
	   on it. */
	for (ap = packet->interface->client->config->reject_list;
	    ap; ap = ap->next) {
		if (addr_eq(packet->client_addr, ap->addr)) {
			note("BOOTREPLY from %s rejected.", piaddr(ap->addr));
			return;
		}
	}
	dhcpoffer(packet);
}

void
dhcp(struct packet *packet)
{
	struct iaddrlist *ap;
	void (*handler)(struct packet *);
	char *type;

	switch (packet->packet_type) {
	case DHCPOFFER:
		handler = dhcpoffer;
		type = "DHCPOFFER";
		break;
	case DHCPNAK:
		handler = dhcpnak;
		type = "DHCPNACK";
		break;
	case DHCPACK:
		handler = dhcpack;
		type = "DHCPACK";
		break;
	default:
		return;
	}

	/* If there's a reject list, make sure this packet's sender isn't
	   on it. */
	for (ap = packet->interface->client->config->reject_list;
	    ap; ap = ap->next) {
		if (addr_eq(packet->client_addr, ap->addr)) {
			note("%s from %s rejected.", type, piaddr(ap->addr));
			return;
		}
	}
	(*handler)(packet);
}

void
dhcpoffer(struct packet *packet)
{
	struct interface_info *ip = packet->interface;
	struct client_lease *lease, *lp;
	int i;
	int arp_timeout_needed = 0, stop_selecting;
	char *name = packet->options[DHO_DHCP_MESSAGE_TYPE].len ?
	    "DHCPOFFER" : "BOOTREPLY";

	/* If we're not receptive to an offer right now, or if the offer
	   has an unrecognizable transaction id, then just drop it. */
	if (ip->client->state != S_SELECTING ||
            packet->interface->client->xid != packet->raw->xid ||
            (packet->interface->hw_address.hlen != packet->raw->hlen) ||
	    (memcmp(packet->interface->hw_address.haddr,
	    packet->raw->chaddr, packet->raw->hlen)))
		return;

	note("%s from %s", name, piaddr(packet->client_addr));


	/* If this lease doesn't supply the minimum required parameters,
	   blow it off. */
	for (i = 0; ip->client->config->required_options[i]; i++) {
		if (!packet->options[ip->client->config->
		    required_options[i]].len) {
			note("%s isn't satisfactory.", name);
			return;
		}
	}

	/* If we've already seen this lease, don't record it again. */
	for (lease = ip->client->offered_leases;
	    lease; lease = lease->next) {
		if (lease->address.len == sizeof(packet->raw->yiaddr) &&
		    !memcmp(lease->address.iabuf,
		    &packet->raw->yiaddr, lease->address.len)) {
			debug("%s already seen.", name);
			return;
		}
	}

	lease = packet_to_lease(packet);
	if (!lease) {
		note("packet_to_lease failed.");
		return;
	}

	/* If this lease was acquired through a BOOTREPLY, record that
	   fact. */
	if (!packet->options[DHO_DHCP_MESSAGE_TYPE].len)
		lease->is_bootp = 1;

	/* Record the medium under which this lease was offered. */
	lease->medium = ip->client->medium;

	/* Send out an ARP Request for the offered IP address. */
        if( !check_arp( ip, lease ) ) {
            note("Arp check failed\n");
            return;
        }

	/* Figure out when we're supposed to stop selecting. */
	stop_selecting =
	    ip->client->first_sending + ip->client->config->select_interval;

	/* If this is the lease we asked for, put it at the head of the
	   list, and don't mess with the arp request timeout. */
	if (lease->address.len == ip->client->requested_address.len &&
	    !memcmp(lease->address.iabuf,
	    ip->client->requested_address.iabuf,
	    ip->client->requested_address.len)) {
		lease->next = ip->client->offered_leases;
		ip->client->offered_leases = lease;
	} else {
		/* If we already have an offer, and arping for this
		   offer would take us past the selection timeout,
		   then don't extend the timeout - just hope for the
		   best. */
		if (ip->client->offered_leases &&
		    (cur_time + arp_timeout_needed) > stop_selecting)
			arp_timeout_needed = 0;

		/* Put the lease at the end of the list. */
		lease->next = NULL;
		if (!ip->client->offered_leases)
			ip->client->offered_leases = lease;
		else {
			for (lp = ip->client->offered_leases; lp->next;
			    lp = lp->next)
				;	/* nothing */
			lp->next = lease;
		}
	}

	/* If we're supposed to stop selecting before we've had time
	   to wait for the ARPREPLY, add some delay to wait for
	   the ARPREPLY. */
	if (stop_selecting - cur_time < arp_timeout_needed)
		stop_selecting = cur_time + arp_timeout_needed;

	/* If the selecting interval has expired, go immediately to
	   state_selecting().  Otherwise, time out into
	   state_selecting at the select interval. */
	if (stop_selecting <= 0)
		state_selecting(ip);
	else {
		add_timeout(stop_selecting, state_selecting, ip);
		cancel_timeout(send_discover, ip);
	}
}

/* Allocate a client_lease structure and initialize it from the parameters
   in the specified packet. */

struct client_lease *
packet_to_lease(struct packet *packet)
{
	struct client_lease *lease;
	int i;

	lease = malloc(sizeof(struct client_lease));

	if (!lease) {
		warning("dhcpoffer: no memory to record lease.");
		return (NULL);
	}

	memset(lease, 0, sizeof(*lease));

	/* Copy the lease options. */
	for (i = 0; i < 256; i++) {
		if (packet->options[i].len) {
			lease->options[i].data =
			    malloc(packet->options[i].len + 1);
			if (!lease->options[i].data) {
				warning("dhcpoffer: no memory for option %d", i);
				free_client_lease(lease);
				return (NULL);
			} else {
				memcpy(lease->options[i].data,
				    packet->options[i].data,
				    packet->options[i].len);
				lease->options[i].len =
				    packet->options[i].len;
				lease->options[i].data[lease->options[i].len] =
				    0;
			}
			if (!check_option(lease,i)) {
				/* ignore a bogus lease offer */
				warning("Invalid lease option - ignoring offer");
				free_client_lease(lease);
				return (NULL);
			}
		}
	}

	lease->address.len = sizeof(packet->raw->yiaddr);
	memcpy(lease->address.iabuf, &packet->raw->yiaddr, lease->address.len);
#ifdef _REACTOS_
	lease->serveraddress.len = sizeof(packet->raw->siaddr);
	memcpy(lease->serveraddress.iabuf, &packet->raw->siaddr, lease->address.len);
#endif

	/* If the server name was filled out, copy it. */
	if ((!packet->options[DHO_DHCP_OPTION_OVERLOAD].len ||
	    !(packet->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 2)) &&
	    packet->raw->sname[0]) {
		lease->server_name = malloc(DHCP_SNAME_LEN + 1);