dhcpc_subr.c

vxworks下dhcpc,dhcpr,dhcps库源码

    /* insert message type */

    dhcpcMsgOut.dhcp->options[offopt++] = _DHCP_MSGTYPE_TAG;
    dhcpcMsgOut.dhcp->options[offopt++] = 1;
    dhcpcMsgOut.dhcp->options[offopt++] = DHCPDECLINE;

    /* insert requested IP */

    if (pReqSpec->ipaddr.s_addr == 0)
        return (0);

    dhcpcMsgOut.dhcp->options[offopt++] = _DHCP_REQUEST_IPADDR_TAG;
    dhcpcMsgOut.dhcp->options[offopt++] = 4;
    bcopy ((char *) &pReqSpec->ipaddr, &dhcpcMsgOut.dhcp->options[offopt], 4);
    offopt += 4;

    /* insert client identifier */

    if (pReqSpec->clid != NULL) {
        dhcpcMsgOut.dhcp->options[offopt++] = _DHCP_CLIENT_ID_TAG;
        dhcpcMsgOut.dhcp->options[offopt++] = pReqSpec->clid->len;
        bcopy (pReqSpec->clid->id, &dhcpcMsgOut.dhcp->options[offopt], pReqSpec->clid->len);
        offopt += pReqSpec->clid->len;
    }

    /* insert server identifier */

    dhcpcMsgOut.dhcp->options[offopt++] = _DHCP_SERVER_ID_TAG;
    dhcpcMsgOut.dhcp->options[offopt++] = 4;
    bcopy ((char *) &pReqSpec->srvaddr, &dhcpcMsgOut.dhcp->options[offopt], 4);
    offopt += 4;

    /* Insert error message, if available. */

    if (pReqSpec->dhcp_errmsg != NULL) {
        dhcpcMsgOut.dhcp->options[offopt++] = _DHCP_ERRMSG_TAG;
        dhcpcMsgOut.dhcp->options[offopt++] = strlen (pReqSpec->dhcp_errmsg);
        bcopy (pReqSpec->dhcp_errmsg, &dhcpcMsgOut.dhcp->options[offopt],
               strlen (pReqSpec->dhcp_errmsg));
        offopt += strlen (pReqSpec->dhcp_errmsg);
    }
    dhcpcMsgOut.dhcp->options[offopt] = _DHCP_END_TAG;

    /*
     * For backward compatibility with earlier DHCP servers, set the
     * reported message size to be at least as large as a BOOTP message.
     */

    msgsize = (DFLTDHCPLEN - DFLTOPTLEN) + offopt + 1;
    if (msgsize < DFLTBOOTPLEN)
        msgsize = DFLTBOOTPLEN;

    /* construct udp part */

    dhcpcMsgOut.udp->uh_sport = dhcpc_port;
    dhcpcMsgOut.udp->uh_dport = dhcps_port;
    dhcpcMsgOut.udp->uh_ulen = htons (msgsize + UDPHL);
    dhcpcMsgOut.udp->uh_sum = 0;

    /* fill pseudo udp header */

    pudph.srcip.s_addr = 0;
    pudph.dstip.s_addr = pReqSpec->srvaddr.s_addr;
    pudph.zero = 0;
    pudph.prto = IPPROTO_UDP;
    pudph.ulen = dhcpcMsgOut.udp->uh_ulen;
    dhcpcMsgOut.udp->uh_sum = udp_cksum (&pudph, (char *) dhcpcMsgOut.udp, ntohs (pudph.ulen));

    /* construct ip part */

#if BSD<44
    dhcpcMsgOut.ip->ip_v_hl = 0;
    dhcpcMsgOut.ip->ip_v_hl = IPVERSION << 4;
    dhcpcMsgOut.ip->ip_v_hl |= IPHL >> 2;
#else
    dhcpcMsgOut.ip->ip_v = IPVERSION;
    dhcpcMsgOut.ip->ip_hl = IPHL >> 2;
#endif
    dhcpcMsgOut.ip->ip_tos = 0;
    dhcpcMsgOut.ip->ip_len = htons (msgsize + UDPHL + IPHL);
    tmpul = generate_xid (pIfData);
    tmpul += (tmpul >> 16);
    dhcpcMsgOut.ip->ip_id = (u_short) (~tmpul);
    dhcpcMsgOut.ip->ip_off = htons (IP_DF); /* XXX */
    dhcpcMsgOut.ip->ip_ttl = 0x20;  /* XXX */
    dhcpcMsgOut.ip->ip_p = IPPROTO_UDP;

    msgsize += UDPHL + IPHL;

    dhcpcMsgOut.ip->ip_src.s_addr = 0;
    dhcpcMsgOut.ip->ip_dst.s_addr = INADDR_BROADCAST;
    dhcpcMsgOut.ip->ip_sum = 0;

#if BSD<44
    dhcpcMsgOut.ip->ip_sum = checksum ((u_short *) dhcpcMsgOut.ip,
                                       (dhcpcMsgOut.ip->ip_v_hl & 0xf) << 2);
#else
    dhcpcMsgOut.ip->ip_sum = checksum ((u_short *) dhcpcMsgOut.ip, dhcpcMsgOut.ip->ip_hl << 2);
#endif

    return (msgsize);
}

/*******************************************************************************
*
* make_release - construct a DHCP release message
*
* This routine constructs an outgoing UDP/IP message containing the values
* required to relinquish the active lease.
*
* RETURNS: Size of DHCP message, in bytes
*
* ERRNO: N/A
*
* NOMANUAL
*/

int make_release (struct dhcp_reqspec *pReqSpec, struct if_info *pIfData,   /* interface used by lease */
                  BOOL oldFlag  /* Use older (padded) DHCP message format? */
    )
{
    int offopt = 0;             /* offset in options field */
    int msgsize;

    /* construct dhcp part */

    bzero (sbuf.buf, sbuf.size);
    dhcpcMsgOut.dhcp->op = BOOTREQUEST;
    dhcpcMsgOut.dhcp->htype = pIfData->haddr.htype;
    dhcpcMsgOut.dhcp->hlen = pIfData->haddr.hlen;
    dhcpcMsgOut.dhcp->xid = htonl (generate_xid (pIfData));
    dhcpcMsgOut.dhcp->ciaddr = pReqSpec->ipaddr;
    bcopy (pIfData->haddr.haddr, dhcpcMsgOut.dhcp->chaddr, dhcpcMsgOut.dhcp->hlen);

    /* insert magic cookie */

    bcopy ((char *) dhcpCookie, dhcpcMsgOut.dhcp->options, MAGIC_LEN);
    offopt = MAGIC_LEN;

    /* insert message type */

    dhcpcMsgOut.dhcp->options[offopt++] = _DHCP_MSGTYPE_TAG;
    dhcpcMsgOut.dhcp->options[offopt++] = 1;
    dhcpcMsgOut.dhcp->options[offopt++] = DHCPRELEASE;

    /* insert client identifier */

    if (pReqSpec->clid != NULL) {
        dhcpcMsgOut.dhcp->options[offopt++] = _DHCP_CLIENT_ID_TAG;
        dhcpcMsgOut.dhcp->options[offopt++] = pReqSpec->clid->len;
        bcopy (pReqSpec->clid->id, &dhcpcMsgOut.dhcp->options[offopt], pReqSpec->clid->len);
        offopt += pReqSpec->clid->len;
    }

    /* insert server identifier */

    dhcpcMsgOut.dhcp->options[offopt++] = _DHCP_SERVER_ID_TAG;
    dhcpcMsgOut.dhcp->options[offopt++] = 4;
    bcopy ((char *) &pReqSpec->srvaddr, &dhcpcMsgOut.dhcp->options[offopt], 4);
    offopt += 4;

    /* Insert error message, if available. */

    if (pReqSpec->dhcp_errmsg != NULL) {
        dhcpcMsgOut.dhcp->options[offopt++] = _DHCP_ERRMSG_TAG;
        dhcpcMsgOut.dhcp->options[offopt++] = strlen (pReqSpec->dhcp_errmsg);
        bcopy (pReqSpec->dhcp_errmsg, &dhcpcMsgOut.dhcp->options[offopt],
               strlen (pReqSpec->dhcp_errmsg));
        offopt += strlen (pReqSpec->dhcp_errmsg);
    }
    dhcpcMsgOut.dhcp->options[offopt] = _DHCP_END_TAG;

    msgsize = (DFLTDHCPLEN - DFLTOPTLEN) + offopt + 1;

    if (oldFlag) {
        /*
         * This flag indicates that the client did not receive a response
         * to the initial set of discover messages but did receive one
         * using the older message format. The (older) responding server
         * ignores messages less than the minimum length obtained with a
         * fixed options field, so pad the message to reach that length.
         */

        if (msgsize < DFLTDHCPLEN)
            msgsize = DFLTDHCPLEN;
    }

    return (msgsize);
}

/*******************************************************************************
*
* dhcp_decline - send a DHCP decline message
*
* This routine constructs a message declining an offered IP address and sends
* it directly to the responding server. It is called when an ARP request 
* detects that the offered address is already in use.
*
* RETURNS: 0 if message sent, or -1 on error.
*
* ERRNO: N/A
*
* NOMANUAL
*/

int dhcp_decline (struct dhcp_reqspec *pDhcpcReqSpec, struct if_info *pIfData   /* interface used by lease */
    )
{
    struct sockaddr_in dest;    /* Server's destination address */
    struct ifnet *pIf;          /* Transmit device */
    int length;                 /* Amount of data in message */

#ifdef DHCPC_DEBUG
    char output[INET_ADDR_LEN];
#endif

    if (pDhcpcReqSpec->srvaddr.s_addr == 0)
        return (-1);

    length = make_decline (pDhcpcReqSpec, pIfData);
    if (length == 0)
        return (-1);

    bzero ((char *) &dest, sizeof (struct sockaddr_in));

    dest.sin_len = sizeof (struct sockaddr_in);
    dest.sin_family = AF_INET;
    dest.sin_addr.s_addr = INADDR_BROADCAST;

    pIf = pIfData->iface;

    if (dhcpSend (pIf, &dest, sbuf.buf, length, TRUE) == ERROR) {
#ifdef DHCPC_DEBUG
        logMsg ("Can't send DHCPDECLINE.\n", 0, 0, 0, 0, 0, 0);
#endif
        return (-1);
    }
#ifdef DHCPC_DEBUG
    inet_ntoa_b (pDhcpcReqSpec->ipaddr, output);
    logMsg ("send DHCPDECLINE(%s)\n", (int) output, 0, 0, 0, 0, 0);
#endif
    return (0);
}

/*******************************************************************************
*
* dhcp_release - send a DHCP release message
*
* This routine constructs a message declining an offered IP address and sends
* it directly to the responding server. It is called when an error prevents
* the use of an acquired lease, or when the lease is relinquished manually
* by a dhcpcRelease() or dhcpcShutdown() call. The message is sent directly to 
* the responding DHCP server.
*
* RETURNS: 0 if message sent, or -1 on error.
*
* ERRNO: N/A
*
* NOMANUAL
*/

int dhcp_release (struct dhcp_reqspec *pDhcpcReqSpec, struct if_info *pIfData,  /* interface used by lease */
                  BOOL oldFlag  /* Use older (padded) DHCP message format? */
    )
{
#ifdef DHCPC_DEBUG
    char output[INET_ADDR_LEN];
#endif
    int length;

    if (pDhcpcReqSpec->srvaddr.s_addr == 0)
        return (-1);

    /* send DHCP message */

    length = make_release (pDhcpcReqSpec, pIfData, oldFlag);

    if (send_unicast (&pDhcpcReqSpec->srvaddr, dhcpcMsgOut.dhcp, length) < 0)
        return (-1);

#ifdef DHCPC_DEBUG
    inet_ntoa_b (pDhcpcReqSpec->ipaddr, output);
    logMsg ("send DHCPRELEASE(%s)\n", (int) output, 0, 0, 0, 0, 0);
#endif
    return (0);
}

/*******************************************************************************
*
* dhcpcPrivateCleanup - remove data structures from client library
*
* The dhcpcCleanup routine uses this routine to release the locally
* allocated data structures which the initialize() call creates. It is
* part of the shutdown process for the DHCP client library. The routine
* executes after all leases are inactive and their data is released.
*
* RETURNS: N/A
*
* ERRNO: N/A
*
* NOMANUAL
*/

void
dhcpcPrivateCleanup (void)
{
    /* Close open file and remove BPF device for ARP probe. */

    close (bpfArpDev);

    bpfDevDelete ("/bpf/dhcpc-arp");

    /* Release transmission buffer. */

    free (sbuf.buf);

    return;
}

/*******************************************************************************
*
* set_declinfo - initialize request specification for decline message
*
* This routine assigns the fields in the request specifier used to construct
* messages to the appropriate values for a DHCP decline message according to
* the parameters of the currently active lease.
*
* RETURNS: N/A
*
* ERRNO: N/A
*
* NOMANUAL
*/

void set_declinfo
    (struct dhcp_reqspec *pDhcpcReqSpec, LEASE_DATA * pLeaseData, char *errmsg, int arpans)
{
    char output[INET_ADDR_LEN];
    struct dhcp_param *paramp;

    paramp = pLeaseData->dhcpcParam;

    pDhcpcReqSpec->ipaddr = paramp->yiaddr;
    pDhcpcReqSpec->srvaddr = paramp->server_id;
    if (pLeaseData->leaseReqSpec.clid != NULL)
        pDhcpcReqSpec->clid = pLeaseData->leaseReqSpec.clid;
    else
        pDhcpcReqSpec->clid = NULL;
    if (errmsg[0] == 0) {
        inet_ntoa_b (paramp->yiaddr, output);
        if (arpans != OK)
            sprintf (errmsg, "IP address (%s) is already in use.", output);
        else
            sprintf (errmsg, "IP address (%s) doesn't match requested value.", output);
    }
    pDhcpcReqSpec->dhcp_errmsg = errmsg;

    return;
}

/*******************************************************************************
*
* set_relinfo - initialize request specification for release message
*
* This routine assigns the fields in the request specifier used to construct
* messages to the appropriate values for a DHCP release message according to
* the parameters of the currently active lease.
*
* RETURNS: N/A
*
* ERRNO: N/A
*
* NOMANUAL
*/

void set_relinfo (struct dhcp_reqspec *pDhcpcReqSpec, LEASE_DATA * pLeaseData, char *errmsg)
{
    char output[INET_ADDR_LEN];
    struct dhcp_param *paramp;

    paramp = pLeaseData->dhcpcParam;

    pDhcpcReqSpec->ipaddr.s_addr = paramp->yiaddr.s_addr;
    pDhcpcReqSpec->srvaddr.s_addr = paramp->server_id.s_addr;
    if (pLeaseData->leaseReqSpec.clid != NULL)
        pDhcpcReqSpec->clid = pLeaseData->leaseReqSpec.clid;
    else
        pDhcpcReqSpec->clid = NULL;
    if (pLeaseData->leaseReqSpec.dhcp_errmsg != NULL)
        pDhcpcReqSpec->dhcp_errmsg = pLeaseData->leaseReqSpec.dhcp_errmsg;
    else {
        inet_ntoa_b (paramp->yiaddr, output);
        sprintf (errmsg, "Releasing the current IP address (%s).", output);
        pDhcpcReqSpec->dhcp_errmsg = errmsg;
    }
    return;
}

/*******************************************************************************
*
* make_discover - construct a DHCP discover message
*
* This routine constructs an outgoing UDP/IP message containing the values
* required to broadcast a lease request. The <xidFlag> indicates whether
* a transaction ID should be generated. Because multiple leases are supported,
* the