dhcp_00.c

完整的Bell实验室的嵌入式文件系统TFS

/* dhcp_00.c:
 *  This file contains the functions that are called from dhcpboot.c if the
 *  the default DHCP interaction is to be done by the monitor.  Whenever a 
 *  new dhcp_XX.c file is created, this file should be used as the template.
 *
 *  General notice:
 *  This code is part of a boot-monitor package developed as a generic base
 *  platform for embedded system designs.  As such, it is likely to be
 *  distributed to various projects beyond the control of the original
 *  author.  Please notify the author of any enhancements made or bugs found
 *  so that all may benefit from the changes.  In addition, notification back
 *  to the author will allow the new user to pick up changes that may have
 *  been made by other users after this version of the code was distributed.
 *
 *  Note1: the majority of this code was edited with 4-space tabs.
 *  Note2: as more and more contributions are accepted, the term "author"
 *         is becoming a mis-representation of credit.
 *
 *  Original author:    Ed Sutter
 *  Email:              [e-mail]
 *  Phone:              908-582-2351
 */

#include "config.h"
#include "cpuio.h"
#include "ether.h"
#include "tfs.h"
#include "tfsprivate.h"
#include "genlib.h"
#include "endian.h"
#include "stddefs.h"

#if INCLUDE_DHCPBOOT

/* ValidDHCPOffer():
 *  Target issued the DISCOVER, the incoming packet is the server's
 *  OFFER reply.  If the DHCPOFFRFLTR shell variable is not present, then
 *  return 1 indicating acceptance of the offer.  If the DHCPOFFRFLTR variable
 *  exists, then use its content to determine if the offer should be accepted...
 *  
 *  Shell variable syntax:
 *  
 *  DHCP_FIELD_IDENTIFIER,EXPECTED_STRING
 *  
 *  where DHCP_FIELD_IDENTIFIER can be...
 *      BFN     bootfile name
 *      SHN     server-host name
 *      VSO###  vendor-specific option number (options encapsulated within
 *              the Vendor-Specific Information (#43) option)
 *      SSO###  site-specific option number (range 128-254)
 * 
 *  For example:
 *  1...
 *      if DHCPOFFRFLTR contains "BFN,abcfile"
 *      then the offer will only be accepted if the bootfile specified by the
 *      dhcp server contains the string "abcfile".
 *  2...
 *      if DHCPOFFRFLTR contains "SHN,a_host_name"
 *      then the offer will only be accepted if the server-hostname specified
 *      by the dhcp server contains the string "a_host_name".
 *  3...
 *      if DHCPOFFRFLTR contains "VSO18,some_String"
 *      then the offer will only be accepted if the server returns vendor-
 *      specific option # 18 and it contains the string "some_String".
 *
 *  Note that "containing the string" means that the string specified in
 *  the DHCPOFFRFLTR shell variable can be the entire string or a sub-string
 *  within the server's response.
 */
int
ValidDHCPOffer(struct   dhcphdr *dhdr)
{
    char *var;
    int offeraccepted, badsyntax;

    /* If no DHCPOFFRFLTR var, accept the offer... */
    var = getenv("DHCPOFFRFLTR");
    if (!var)   
        return(1);

    /* Start off by assuming acceptance... */
    badsyntax = 0;
    offeraccepted = 1;

    /* Now process the DHCPOFFRFLTR variable and incoming dhcp data,
     * and clear the offeraccepted (or set badsyntax) flag if necessary...
     */

    if (!strncmp(var,"BFN,",4)) {
        if (!strstr(dhdr->bootfile,var+4))
            offeraccepted = 0;
    }
    else if (!strncmp(var,"SHN,",4)) {
        if (!strstr(dhdr->server_hostname,var+4))
            offeraccepted = 0;
    }
    else if ((!strncmp(var,"SSO",3)) || (!strncmp(var,"VSO",3))) {
        int optno;
        ulong cookie;
        char *comma, *optval, *vso;

        optno = atoi(var+3);
        comma = strchr(var,',');
        memcpy((char *)&cookie,(char *)&dhdr->magic_cookie,4);
        if (cookie != ecl(STANDARD_MAGIC_COOKIE))
            offeraccepted = 0;
        else if (!comma)
            badsyntax = 1;
        else if (var[0] == 'S') {
            if ((optno < 128) || (optno > 254))
                badsyntax = 1;
            else {
                optval = DhcpGetOption(optno,dhdr+1);
                if (!optval)
                    offeraccepted = 0;
                else {
                    if (!strstr(optval+2,comma+1))
                        offeraccepted = 0;
                }
            }
        }
        else if (var[0] == 'V') {
            if ((optno < 0) || (optno > 254))
                badsyntax = 1;
            else {
                vso = DhcpGetOption(DHCPOPT_VENDORSPECIFICINFO,dhdr+1);
                if (!vso)
                    offeraccepted = 0;
                else {
                    optval = DhcpGetOption(optno,vso+2);
                    if (!optval)
                        offeraccepted = 0;
                    else {
                        if (!strstr(optval+2,comma+1))
                            offeraccepted = 0;
                    }
                }
            }
        }
    }
    else {
        badsyntax = 1;
    }
    if (badsyntax) {
        printf("Bad DHCPOFFRFLTR syntax.\n");
        offeraccepted = 0;
    }
    return(offeraccepted);
}

/* DhcpVendorSpecific():
 *  Process any vendor specific data from the incoming header.
 */
void
DhcpVendorSpecific(struct dhcphdr *dhdr)
{
    return;         /* Obviously, the default is no processing. */
}

/* printDhcpVSopt():
 *  Input is the option, the option length and the pointer to the options.
 *  Print the option.
 */
int
printDhcpVSopt(int vsopt, int vsoptlen, char *options)
{
    return(0);
}

/* buildDhcpHdr():
 *  Called by dhcpboot.c to allow application-specific header stuff to
 *  be added to header.  Return 0 if generic stuff in dhcpboot.c is to be
 *  used; else return 1 and the calling code will assume this function is
 *  dealing with it (see dhcpboot.c for basic idea).
 */
int
buildDhcpHdr(struct dhcphdr *dhdr)
{
    return(0);
}

/* DhcpBootpLoadVSA():
 *  Called by DhcpBootpDone to store an ascii-coded-hex copy of the 
 *  vendor-specific-area (BOOTP) or options (DHCP) in the shell variable
 *  DHCPVSA.
 */
void
DhcpBootpLoadVSA(uchar *vsabin, int vsize)
{
    int i;
    uchar   *cp, *vsaacx;

    /* If after the transaction has completed, the RLYAGNT is   */
    /* set, but GIPADD is not set, copy RLYAGNT to GIPADD...    */
    if (!getenv("GIPADD") && getenv("RLYAGNT"))
        setenv("GIPADD",getenv("RLYAGNT"));

    /* If allocation succeeds, then copy BOOTP VendorSpecificArea to the */
    /* DHCPVSA shell variable. Copy it as ascii-coded hex */
    vsaacx = (uchar *)malloc((vsize*2)+4);
    if (vsaacx) {
        cp = vsaacx;
        for(i=0;i<vsize;i++,cp+=2)
            sprintf(cp,"%02x",vsabin[i]);
        *cp = 0;
        setenv("DHCPVSA",vsaacx);
        free(vsaacx);
    }
    else
        printf("DHCPVSA space allocation failed\n");
}


/* DhcpBootpDone():
 *  Called at the end of the Bootp or Dhcp transaction.
 *  Input...
 *  bootp:  1 if BOOTP; else DHCP.
 *  dhdr:   pointer to dhcp or bootp header.
 *  vsize:  size of vendor specific area (for bootp this is fixed at 64, 
 *          but for dhcp it is variable).
 */
void
DhcpBootpDone(int bootp, struct dhcphdr *dhdr, int vsize)
{
    if (bootp) {
        struct bootphdr *bhdr;

        bhdr = (struct bootphdr *)dhdr;
        DhcpBootpLoadVSA(bhdr->vsa,vsize);
    }
    else {
        DhcpBootpLoadVSA((uchar *)&dhdr->magic_cookie,vsize);
    }
    return;
}

#endif