/*
 * dovend.c : Inserts all but the first few vendor options.
 */

#include <sys/types.h>

#include <netinet/in.h>
#include <arpa/inet.h>                  /* inet_ntoa */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <syslog.h>

#include "bootp.h"
#include "bootpd.h"
#include "report.h"
#include "dovend.h"

PRIVATE int insert_generic(struct shared_bindata *, byte **, int *);

/*
 * Insert the 2nd part of the options into an option buffer.
 * Return amount of space used.
 *
 * This inserts everything EXCEPT:
 *   magic cookie, subnet mask, gateway, bootsize, extension file
 * Those are handled separately (in bootpd.c) to allow this function
 * to be shared between bootpd and bootpef.
 *
 * When an "extension file" is in use, the options inserted by
 * this function go into the exten_file, not the bootp response.
 */

int
dovend_rfc1497(struct host *hp, byte *buf, int len)
{
        int bytesleft = len;
        byte *vp = buf;

        static const char noroom[] = "%s: No room for \"%s\" option";
#define NEED(LEN, MSG) do                       \
                if (bytesleft < (LEN)) {                    \
                        report(LOG_NOTICE, noroom,          \
                                   hp->hostname->string, MSG);  \
                        return (vp - buf);                  \
                } while (0)

        /*
         * Note that the following have already been inserted:
         *   magic_cookie, subnet_mask, gateway, bootsize
         *
         * The remaining options are inserted in order of importance.
         * (Of course the importance of each is a matter of opinion.)
         * The option insertion order should probably be configurable.
         *
         * This is the order used in the NetBSD version.  Can anyone
         * explain why the time_offset and swap_server are first?
         * Also, why is the hostname so far down the list?  -gwr
         */

        if (hp->flags.time_offset) {
                NEED(6, "to");
                *vp++ = TAG_TIME_OFFSET;/* -1 byte  */
                *vp++ = 4;                              /* -1 byte  */
                insert_u_long(htonl(hp->time_offset), &vp);     /* -4 bytes */
                bytesleft -= 6;
        }
        /*
         * swap server, root path, dump path
         */
        if (hp->flags.swap_server) {
                NEED(6, "sw");
                /* There is just one SWAP_SERVER, so it is not an iplist. */
                *vp++ = TAG_SWAP_SERVER;/* -1 byte  */
                *vp++ = 4;                              /* -1 byte  */
                insert_u_long(hp->swap_server.s_addr, &vp);     /* -4 bytes */
                bytesleft -= 6;                 /* Fix real count */
        }
        if (hp->flags.root_path) {
                /*
                 * Check for room for root_path.  Add 2 to account for
                 * TAG_ROOT_PATH and length.
                 */
                len = strlen(hp->root_path->string);
                NEED((len + 2), "rp");
                *vp++ = TAG_ROOT_PATH;
                *vp++ = (byte) (len & 0xFF);
                bcopy(hp->root_path->string, vp, len);
                vp += len;
                bytesleft -= len + 2;
        }
        if (hp->flags.dump_file) {
                /*
                 * Check for room for dump_file.  Add 2 to account for
                 * TAG_DUMP_FILE and length.
                 */
                len = strlen(hp->dump_file->string);
                NEED((len + 2), "df");
                *vp++ = TAG_DUMP_FILE;
                *vp++ = (byte) (len & 0xFF);
                bcopy(hp->dump_file->string, vp, len);
                vp += len;
                bytesleft -= len + 2;
        }
        /*
         * DNS server and domain
         */
        if (hp->flags.domain_server) {
                if (insert_ip(TAG_DOMAIN_SERVER,
                                          hp->domain_server,
                                          &vp, &bytesleft))
                        NEED(8, "ds");
        }
        if (hp->flags.domain_name) {
                /*
                 * Check for room for domain_name.  Add 2 to account for
                 * TAG_DOMAIN_NAME and length.
                 */
                len = strlen(hp->domain_name->string);
                NEED((len + 2), "dn");
                *vp++ = TAG_DOMAIN_NAME;
                *vp++ = (byte) (len & 0xFF);
                bcopy(hp->domain_name->string, vp, len);
                vp += len;
                bytesleft -= len + 2;
        }
        /*
         * NIS (YP) server and domain
         */
        if (hp->flags.nis_server) {
                if (insert_ip(TAG_NIS_SERVER,
                                          hp->nis_server,
                                          &vp, &bytesleft))
                        NEED(8, "ys");
        }
        if (hp->flags.nis_domain) {
                /*
                 * Check for room for nis_domain.  Add 2 to account for
                 * TAG_NIS_DOMAIN and length.
                 */
                len = strlen(hp->nis_domain->string);
                NEED((len + 2), "yn");
                *vp++ = TAG_NIS_DOMAIN;
                *vp++ = (byte) (len & 0xFF);
                bcopy(hp->nis_domain->string, vp, len);
                vp += len;
                bytesleft -= len + 2;
        }
        /* IEN 116 name server */
        if (hp->flags.name_server) {
                if (insert_ip(TAG_NAME_SERVER,
                                          hp->name_server,
                                          &vp, &bytesleft))
                        NEED(8, "ns");
        }
        if (hp->flags.rlp_server) {
                if (insert_ip(TAG_RLP_SERVER,
                                          hp->rlp_server,
                                          &vp, &bytesleft))
                        NEED(8, "rl");
        }
        /* Time server (RFC 868) */
        if (hp->flags.time_server) {
                if (insert_ip(TAG_TIME_SERVER,
                                          hp->time_server,
                                          &vp, &bytesleft))
                        NEED(8, "ts");
        }
        /* NTP (time) Server (RFC 1129) */
        if (hp->flags.ntp_server) {
                if (insert_ip(TAG_NTP_SERVER,
                                          hp->ntp_server,
                                          &vp, &bytesleft))
                        NEED(8, "nt");
        }
        /*
         * I wonder:  If the hostname were "promoted" into the BOOTP
         * response part, might these "extension" files possibly be
         * shared between several clients?
         *
         * Also, why not just use longer BOOTP packets with all the
         * additional length used as option data.  This bootpd version
         * already supports that feature by replying with the same
         * packet length as the client request packet. -gwr
         */
        if (hp->flags.name_switch && hp->flags.send_name) {
                /*
                 * Check for room for hostname.  Add 2 to account for
                 * TAG_HOST_NAME and length.
                 */
                len = strlen(hp->hostname->string);
#if 0
                /*
                 * XXX - Too much magic.  The user can always set the hostname
                 * to the short version in the bootptab file. -gwr
                 */
                if ((len + 2) > bytesleft) {
                        /*
                         * Not enough room for full (domain-qualified) hostname, try
                         * stripping it down to just the first field (host).
                         */
                        char *tmpstr = hp->hostname->string;
                        len = 0;
                        while (*tmpstr && (*tmpstr != '.')) {
                                tmpstr++;
                                len++;
                        }
                }
#endif
                NEED((len + 2), "hn");
                *vp++ = TAG_HOST_NAME;
                *vp++ = (byte) (len & 0xFF);
                bcopy(hp->hostname->string, vp, len);
                vp += len;
                bytesleft -= len + 2;
        }
        /*
         * The rest of these are less important, so they go last.
         */
        if (hp->flags.lpr_server) {
                if (insert_ip(TAG_LPR_SERVER,
                                          hp->lpr_server,
                                          &vp, &bytesleft))
                        NEED(8, "lp");
        }
        if (hp->flags.cookie_server) {
                if (insert_ip(TAG_COOKIE_SERVER,
                                          hp->cookie_server,
                                          &vp, &bytesleft))
                        NEED(8, "cs");
        }
        if (hp->flags.log_server) {
                if (insert_ip(TAG_LOG_SERVER,
                                          hp->log_server,
                                          &vp, &bytesleft))
                        NEED(8, "lg");
        }
        /*
         * XXX - Add new tags here (to insert options)
         */
        if (hp->flags.generic) {
                if (insert_generic(hp->generic, &vp, &bytesleft))
                        NEED(64, "(generic)");
        }
        /*
         * The end marker is inserted by the caller.
         */
        return (vp - buf);
#undef  NEED
}                                                               /* dovend_rfc1497 */



/*
 * Insert a tag value, a length value, and a list of IP addresses into the
 * memory buffer indirectly pointed to by "dest".  "tag" is the RFC1048 tag
 * number to use, "iplist" is a pointer to a list of IP addresses
 * (struct in_addr_list), and "bytesleft" points to an integer which
 * indicates the size of the "dest" buffer.
 *
 * Return zero if everything fits.
 *
 * This is used to fill the vendor-specific area of a bootp packet in
 * conformance to RFC1048.
 */

int
insert_ip(byte tag, struct in_addr_list *iplist, byte **dest, int *bytesleft)
{
        struct in_addr *addrptr;
        unsigned addrcount = 1;
        byte *d;

        if (iplist == NULL)
                return (0);

        if (*bytesleft >= 6) {
                d = *dest;                              /* Save pointer for later */
                **dest = tag;
                (*dest) += 2;
                (*bytesleft) -= 2;              /* Account for tag and length */
                addrptr = iplist->addr;
                addrcount = iplist->addrcount;
                while ((*bytesleft >= 4) && (addrcount > 0)) {
                        insert_u_long(addrptr->s_addr, dest);
                        addrptr++;
                        addrcount--;
                        (*bytesleft) -= 4;      /* Four bytes per address */
                }
                d[1] = (byte) ((*dest - d - 2) & 0xFF);
        }
        return (addrcount);
}



/*
 * Insert generic data into a bootp packet.  The data is assumed to already
 * be in RFC1048 format.  It is inserted using a first-fit algorithm which
 * attempts to insert as many tags as possible.  Tags and data which are
 * too large to fit are skipped; any remaining tags are tried until they
 * have all been exhausted.
 * Return zero if everything fits.
 */

static int
insert_generic(struct shared_bindata *gendata, byte **buff, int *bytesleft)
{
        byte *srcptr;
        int length, numbytes;
        int skipped = 0;

        if (gendata == NULL)
                return (0);

        srcptr = gendata->data;
        length = gendata->length;
        while ((length > 0) && (*bytesleft > 0)) {
                switch (*srcptr) {
                case TAG_END:
                        length = 0;                     /* Force an exit on next iteration */
                        break;
                case TAG_PAD:
                        *(*buff)++ = *srcptr++;
                        (*bytesleft)--;
                        length--;
                        break;
                default:
                        numbytes = srcptr[1] + 2;
                        if (*bytesleft < numbytes)
                                skipped += numbytes;
                        else {
                                bcopy(srcptr, *buff, numbytes);
                                (*buff) += numbytes;
                                (*bytesleft) -= numbytes;
                        }
                        srcptr += numbytes;
                        length -= numbytes;
                        break;
                }
        } /* while */
        return (skipped);
}

/*
 * Insert the unsigned long "value" into memory starting at the byte
 * pointed to by the byte pointer (*dest).  (*dest) is updated to
 * point to the next available byte.
 *
 * Since it is desirable to internally store network addresses in network
 * byte order (in struct in_addr's), this routine expects longs to be
 * passed in network byte order.
 *
 * However, due to the nature of the main algorithm, the long must be in
 * host byte order, thus necessitating the use of ntohl() first.
 */

void
insert_u_long(u_int32 value, byte **dest)
{
        byte *temp;
        int n;

        value = ntohl(value);           /* Must use host byte order here */
        temp = (*dest += 4);
        for (n = 4; n > 0; n--) {
                *--temp = (byte) (value & 0xFF);
                value >>= 8;
        }
        /* Final result is network byte order */
}

/*
 * Local Variables:
 * tab-width: 4
 * c-indent-level: 4
 * c-argdecl-indent: 4
 * c-continued-statement-offset: 4
 * c-continued-brace-offset: -4
 * c-label-offset: -4
 * c-brace-offset: 0
 * End:
 */