/* vi: set sw=4 ts=4: */
/*
 * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */
#include "common.h"

#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
unsigned dhcp_verbose;
#endif

const uint8_t MAC_BCAST_ADDR[6] ALIGN2 = {
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff
};

#if ENABLE_UDHCPC || ENABLE_UDHCPD
/* Supported options are easily added here.
 * See RFC2132 for more options.
 * OPTION_REQ: these options are requested by udhcpc (unless -o).
 */
const struct dhcp_optflag dhcp_optflags[] = {
        /* flags                                    code */
        { OPTION_IP                   | OPTION_REQ, 0x01 }, /* DHCP_SUBNET        */
        { OPTION_S32                              , 0x02 }, /* DHCP_TIME_OFFSET   */
        { OPTION_IP | OPTION_LIST     | OPTION_REQ, 0x03 }, /* DHCP_ROUTER        */
//      { OPTION_IP | OPTION_LIST                 , 0x04 }, /* DHCP_TIME_SERVER   */
//      { OPTION_IP | OPTION_LIST                 , 0x05 }, /* DHCP_NAME_SERVER   */
        { OPTION_IP | OPTION_LIST     | OPTION_REQ, 0x06 }, /* DHCP_DNS_SERVER    */
//      { OPTION_IP | OPTION_LIST                 , 0x07 }, /* DHCP_LOG_SERVER    */
//      { OPTION_IP | OPTION_LIST                 , 0x08 }, /* DHCP_COOKIE_SERVER */
        { OPTION_IP | OPTION_LIST                 , 0x09 }, /* DHCP_LPR_SERVER    */
        { OPTION_STRING_HOST          | OPTION_REQ, 0x0c }, /* DHCP_HOST_NAME     */
        { OPTION_U16                              , 0x0d }, /* DHCP_BOOT_SIZE     */
        { OPTION_STRING_HOST          | OPTION_REQ, 0x0f }, /* DHCP_DOMAIN_NAME   */
        { OPTION_IP                               , 0x10 }, /* DHCP_SWAP_SERVER   */
        { OPTION_STRING                           , 0x11 }, /* DHCP_ROOT_PATH     */
        { OPTION_U8                               , 0x17 }, /* DHCP_IP_TTL        */
        { OPTION_U16                              , 0x1a }, /* DHCP_MTU           */
//TODO: why do we request DHCP_BROADCAST? Can't we assume that
//in the unlikely case it is different from typical N.N.255.255,
//server would let us know anyway?
        { OPTION_IP                   | OPTION_REQ, 0x1c }, /* DHCP_BROADCAST     */
        { OPTION_IP_PAIR | OPTION_LIST            , 0x21 }, /* DHCP_ROUTES        */
        { OPTION_STRING_HOST                      , 0x28 }, /* DHCP_NIS_DOMAIN    */
        { OPTION_IP | OPTION_LIST                 , 0x29 }, /* DHCP_NIS_SERVER    */
        { OPTION_IP | OPTION_LIST     | OPTION_REQ, 0x2a }, /* DHCP_NTP_SERVER    */
        { OPTION_IP | OPTION_LIST                 , 0x2c }, /* DHCP_WINS_SERVER   */
        { OPTION_U32                              , 0x33 }, /* DHCP_LEASE_TIME    */
        { OPTION_IP                               , 0x36 }, /* DHCP_SERVER_ID     */
        { OPTION_STRING                           , 0x38 }, /* DHCP_ERR_MESSAGE   */
//TODO: must be combined with 'sname' and 'file' handling:
        { OPTION_STRING_HOST                      , 0x42 }, /* DHCP_TFTP_SERVER_NAME */
        { OPTION_STRING                           , 0x43 }, /* DHCP_BOOT_FILE     */
//TODO: not a string, but a set of LASCII strings:
//      { OPTION_STRING                           , 0x4D }, /* DHCP_USER_CLASS    */
        { OPTION_STRING                           , 0x64 }, /* DHCP_PCODE         */
        { OPTION_STRING                           , 0x65 }, /* DHCP_TCODE         */
#if ENABLE_FEATURE_UDHCP_RFC3397
        { OPTION_DNS_STRING | OPTION_LIST         , 0x77 }, /* DHCP_DOMAIN_SEARCH */
        { OPTION_SIP_SERVERS                      , 0x78 }, /* DHCP_SIP_SERVERS   */
#endif
        { OPTION_STATIC_ROUTES | OPTION_LIST      , 0x79 }, /* DHCP_STATIC_ROUTES */
#if ENABLE_FEATURE_UDHCP_8021Q
        { OPTION_U16                              , 0x84 }, /* DHCP_VLAN_ID       */
        { OPTION_U8                               , 0x85 }, /* DHCP_VLAN_PRIORITY */
#endif
        { OPTION_STRING                           , 0xd1 }, /* DHCP_PXE_CONF_FILE */
        { OPTION_STRING                           , 0xd2 }, /* DHCP_PXE_PATH_PREFIX */
        { OPTION_U32                              , 0xd3 }, /* DHCP_REBOOT_TIME   */
        { OPTION_6RD                              , 0xd4 }, /* DHCP_6RD           */
        { OPTION_STATIC_ROUTES | OPTION_LIST      , 0xf9 }, /* DHCP_MS_STATIC_ROUTES */
        { OPTION_STRING                           , 0xfc }, /* DHCP_WPAD          */

        /* Options below have no match in dhcp_option_strings[],
         * are not passed to dhcpc scripts, and cannot be specified
         * with "option XXX YYY" syntax in dhcpd config file.
         * These entries are only used internally by udhcp[cd]
         * to correctly encode options into packets.
         */

        { OPTION_IP                               , 0x32 }, /* DHCP_REQUESTED_IP  */
        { OPTION_U8                               , 0x35 }, /* DHCP_MESSAGE_TYPE  */
        { OPTION_U16                              , 0x39 }, /* DHCP_MAX_SIZE      */
//looks like these opts will work just fine even without these defs:
//      { OPTION_STRING                           , 0x3c }, /* DHCP_VENDOR        */
//      /* not really a string: */
//      { OPTION_STRING                           , 0x3d }, /* DHCP_CLIENT_ID     */
        { 0, 0 } /* zeroed terminating entry */
};

/* Used for converting options from incoming packets to env variables
 * for udhcpc script, and for setting options for udhcpd via
 * "opt OPTION_NAME OPTION_VALUE" directives in udhcpd.conf file.
 */
/* Must match dhcp_optflags[] order */
const char dhcp_option_strings[] ALIGN1 =
        "subnet" "\0"           /* DHCP_SUBNET          */
        "timezone" "\0"         /* DHCP_TIME_OFFSET     */
        "router" "\0"           /* DHCP_ROUTER          */
//      "timesrv" "\0"          /* DHCP_TIME_SERVER     */
//      "namesrv" "\0"          /* DHCP_NAME_SERVER     */
        "dns" "\0"              /* DHCP_DNS_SERVER      */
//      "logsrv" "\0"           /* DHCP_LOG_SERVER      */
//      "cookiesrv" "\0"        /* DHCP_COOKIE_SERVER   */
        "lprsrv" "\0"           /* DHCP_LPR_SERVER      */
        "hostname" "\0"         /* DHCP_HOST_NAME       */
        "bootsize" "\0"         /* DHCP_BOOT_SIZE       */
        "domain" "\0"           /* DHCP_DOMAIN_NAME     */
        "swapsrv" "\0"          /* DHCP_SWAP_SERVER     */
        "rootpath" "\0"         /* DHCP_ROOT_PATH       */
        "ipttl" "\0"            /* DHCP_IP_TTL          */
        "mtu" "\0"              /* DHCP_MTU             */
        "broadcast" "\0"        /* DHCP_BROADCAST       */
        "routes" "\0"           /* DHCP_ROUTES          */
        "nisdomain" "\0"        /* DHCP_NIS_DOMAIN      */
        "nissrv" "\0"           /* DHCP_NIS_SERVER      */
        "ntpsrv" "\0"           /* DHCP_NTP_SERVER      */
        "wins" "\0"             /* DHCP_WINS_SERVER     */
        "lease" "\0"            /* DHCP_LEASE_TIME      */
        "serverid" "\0"         /* DHCP_SERVER_ID       */
        "message" "\0"          /* DHCP_ERR_MESSAGE     */
        "tftp" "\0"             /* DHCP_TFTP_SERVER_NAME*/
        "bootfile" "\0"         /* DHCP_BOOT_FILE       */
//      "userclass" "\0"        /* DHCP_USER_CLASS      */
        "tzstr" "\0"            /* DHCP_PCODE           */
        "tzdbstr" "\0"          /* DHCP_TCODE           */
#if ENABLE_FEATURE_UDHCP_RFC3397
        "search" "\0"           /* DHCP_DOMAIN_SEARCH   */
// doesn't work in udhcpd.conf since OPTION_SIP_SERVERS
// is not handled yet by "string->option" conversion code:
        "sipsrv" "\0"           /* DHCP_SIP_SERVERS     */
#endif
        "staticroutes" "\0"     /* DHCP_STATIC_ROUTES   */
#if ENABLE_FEATURE_UDHCP_8021Q
        "vlanid" "\0"           /* DHCP_VLAN_ID         */
        "vlanpriority" "\0"     /* DHCP_VLAN_PRIORITY   */
#endif
        "pxeconffile" "\0"      /* DHCP_PXE_CONF_FILE   */
        "pxepathprefix" "\0"    /* DHCP_PXE_PATH_PREFIX */
        "reboottime" "\0"       /* DHCP_REBOOT_TIME     */
        "ip6rd" "\0"            /* DHCP_6RD             */
        "msstaticroutes" "\0"   /* DHCP_MS_STATIC_ROUTES*/
        "wpad" "\0"             /* DHCP_WPAD            */
        ;
#endif

/* Lengths of the option types in binary form.
 * Used by:
 * udhcp_str2optset: to determine how many bytes to allocate.
 * xmalloc_optname_optval: to estimate string length
 * from binary option length: (option[LEN] / dhcp_option_lengths[opt_type])
 * is the number of elements, multiply it by one element's string width
 * (len_of_option_as_string[opt_type]) and you know how wide string you need.
 */
const uint8_t dhcp_option_lengths[] ALIGN1 = {
        [OPTION_IP] =      4,
        [OPTION_IP_PAIR] = 8,
//      [OPTION_BOOLEAN] = 1,
        [OPTION_STRING] =  1,  /* ignored by udhcp_str2optset */
        [OPTION_STRING_HOST] = 1,  /* ignored by udhcp_str2optset */
#if ENABLE_FEATURE_UDHCP_RFC3397
        [OPTION_DNS_STRING] = 1,  /* ignored by both udhcp_str2optset and xmalloc_optname_optval */
        [OPTION_SIP_SERVERS] = 1,
#endif
        [OPTION_U8] =      1,
        [OPTION_U16] =     2,
//      [OPTION_S16] =     2,
        [OPTION_U32] =     4,
        [OPTION_S32] =     4,
        /* Just like OPTION_STRING, we use minimum length here */
        [OPTION_STATIC_ROUTES] = 5,
        [OPTION_6RD] =    12,  /* ignored by udhcp_str2optset */
        /* The above value was chosen as follows:
         * len_of_option_as_string[] for this option is >60: it's a string of the form
         * "32 128 ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff 255.255.255.255 ".
         * Each additional ipv4 address takes 4 bytes in binary option and appends
         * another "255.255.255.255 " 16-byte string. We can set [OPTION_6RD] = 4
         * but this severely overestimates string length: instead of 16 bytes,
         * it adds >60 for every 4 bytes in binary option.
         * We cheat and declare here that option is in units of 12 bytes.
         * This adds more than 60 bytes for every three ipv4 addresses - more than enough.
         * (Even 16 instead of 12 should work, but let's be paranoid).
         */
};


#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2
static void log_option(const char *pfx, const uint8_t *opt)
{
        if (dhcp_verbose >= 2) {
                char buf[256 * 2 + 2];
                *bin2hex(buf, (void*) (opt + OPT_DATA), opt[OPT_LEN]) = '\0';
                bb_info_msg("%s: 0x%02x %s", pfx, opt[OPT_CODE], buf);
        }
}
#else
# define log_option(pfx, opt) ((void)0)
#endif

unsigned FAST_FUNC udhcp_option_idx(const char *name, const char *option_strings)
{
        int n = index_in_strings(option_strings, name);
        if (n >= 0)
                return n;

        {
                char *buf, *d;
                const char *s;

                s = option_strings;
                while (*s)
                        s += strlen(s) + 1;

                d = buf = xzalloc(s - option_strings);
                s = option_strings;
                while (!(*s == '\0' && s[1] == '\0')) {
                        *d++ = (*s == '\0' ? ' ' : *s);
                        s++;
                }
                bb_error_msg_and_die("unknown option '%s', known options: %s", name, buf);
        }
}

/* Get an option with bounds checking (warning, result is not aligned) */
uint8_t* FAST_FUNC udhcp_get_option(struct dhcp_packet *packet, int code)
{
        uint8_t *optionptr;
        int len;
        int rem;
        int overload = 0;
        enum {
                FILE_FIELD101  = FILE_FIELD  * 0x101,
                SNAME_FIELD101 = SNAME_FIELD * 0x101,
        };

        /* option bytes: [code][len][data1][data2]..[dataLEN] */
        optionptr = packet->options;
        rem = sizeof(packet->options);
        while (1) {
                if (rem <= 0) {
 complain:
                        bb_error_msg("bad packet, malformed option field");
                        return NULL;
                }

                /* DHCP_PADDING and DHCP_END have no [len] byte */
                if (optionptr[OPT_CODE] == DHCP_PADDING) {
                        rem--;
                        optionptr++;
                        continue;
                }
                if (optionptr[OPT_CODE] == DHCP_END) {
                        if ((overload & FILE_FIELD101) == FILE_FIELD) {
                                /* can use packet->file, and didn't look at it yet */
                                overload |= FILE_FIELD101; /* "we looked at it" */
                                optionptr = packet->file;
                                rem = sizeof(packet->file);
                                continue;
                        }
                        if ((overload & SNAME_FIELD101) == SNAME_FIELD) {
                                /* can use packet->sname, and didn't look at it yet */
                                overload |= SNAME_FIELD101; /* "we looked at it" */
                                optionptr = packet->sname;
                                rem = sizeof(packet->sname);
                                continue;
                        }
                        break;
                }

                if (rem <= OPT_LEN)
                        goto complain; /* complain and return NULL */
                len = 2 + optionptr[OPT_LEN];
                rem -= len;
                if (rem < 0)
                        goto complain; /* complain and return NULL */

                if (optionptr[OPT_CODE] == code) {
                        if (optionptr[OPT_LEN] == 0) {
                                /* So far no valid option with length 0 known.
                                 * Having this check means that searching
                                 * for DHCP_MESSAGE_TYPE need not worry
                                 * that returned pointer might be unsafe
                                 * to dereference.
                                 */
                                goto complain; /* complain and return NULL */
                        }
                        log_option("option found", optionptr);
                        return optionptr + OPT_DATA;
                }

                if (optionptr[OPT_CODE] == DHCP_OPTION_OVERLOAD) {
                        if (len >= 3)
                                overload |= optionptr[OPT_DATA];
                        /* fall through */
                }
                optionptr += len;
        }

        /* log3 because udhcpc uses it a lot - very noisy */
        log3("option 0x%02x not found", code);
        return NULL;
}

uint8_t* FAST_FUNC udhcp_get_option32(struct dhcp_packet *packet, int code)
{
        uint8_t *r = udhcp_get_option(packet, code);
        if (r) {
                if (r[-OPT_DATA + OPT_LEN] != 4)
                        r = NULL;
        }
        return r;
}

/* Return the position of the 'end' option (no bounds checking) */
int FAST_FUNC udhcp_end_option(uint8_t *optionptr)
{
        int i = 0;

        while (optionptr[i] != DHCP_END) {
                if (optionptr[i] != DHCP_PADDING)
                        i += optionptr[i + OPT_LEN] + OPT_DATA-1;
                i++;
        }
        return i;
}

/* Add an option (supplied in binary form) to the options.
 * Option format: [code][len][data1][data2]..[dataLEN]
 */
void FAST_FUNC udhcp_add_binary_option(struct dhcp_packet *packet, uint8_t *addopt)
{
        unsigned len;
        uint8_t *optionptr = packet->options;
        unsigned end = udhcp_end_option(optionptr);

        len = OPT_DATA + addopt[OPT_LEN];
        /* end position + (option code/length + addopt length) + end option */
        if (end + len + 1 >= DHCP_OPTIONS_BUFSIZE) {
//TODO: learn how to use overflow option if we exhaust packet->options[]
                bb_error_msg("option 0x%02x did not fit into the packet",
                                addopt[OPT_CODE]);
                return;
        }
        log_option("adding option", addopt);
        memcpy(optionptr + end, addopt, len);
        optionptr[end + len] = DHCP_END;
}

#if ENABLE_UDHCPC || ENABLE_UDHCPD
/* Add an one to four byte option to a packet */
void FAST_FUNC udhcp_add_simple_option(struct dhcp_packet *packet, uint8_t code, uint32_t data)
{
        const struct dhcp_optflag *dh;

        for (dh = dhcp_optflags; dh->code; dh++) {
                if (dh->code == code) {
                        uint8_t option[6], len;

                        option[OPT_CODE] = code;
                        len = dhcp_option_lengths[dh->flags & OPTION_TYPE_MASK];
                        option[OPT_LEN] = len;
                        if (BB_BIG_ENDIAN)
                                data <<= 8 * (4 - len);
                        /* Assignment is unaligned! */
                        move_to_unaligned32(&option[OPT_DATA], data);
                        udhcp_add_binary_option(packet, option);
                        return;
                }
        }

        bb_error_msg("can't add option 0x%02x", code);
}
#endif

/* Find option 'code' in opt_list */
struct option_set* FAST_FUNC udhcp_find_option(struct option_set *opt_list, uint8_t code)
{
        while (opt_list && opt_list->data[OPT_CODE] < code)
                opt_list = opt_list->next;

        if (opt_list && opt_list->data[OPT_CODE] == code)
                return opt_list;
        return NULL;
}

/* Parse string to IP in network order */
int FAST_FUNC udhcp_str2nip(const char *str, void *arg)
{
        len_and_sockaddr *lsa;

        lsa = host_and_af2sockaddr(str, 0, AF_INET);
        if (!lsa)
                return 0;
        /* arg maybe unaligned */
        move_to_unaligned32((uint32_t*)arg, lsa->u.sin.sin_addr.s_addr);
        free(lsa);
        return 1;
}

/* udhcp_str2optset:
 * Parse string option representation to binary form and add it to opt_list.
 * Called to parse "udhcpc -x OPTNAME:OPTVAL"
 * and to parse udhcpd.conf's "opt OPTNAME OPTVAL" directives.
 */
/* helper: add an option to the opt_list */
#if !ENABLE_UDHCPC6
#define attach_option(opt_list, optflag, buffer, length, dhcpv6) \
        attach_option(opt_list, optflag, buffer, length)
#endif
static NOINLINE void attach_option(
                struct option_set **opt_list,
                const struct dhcp_optflag *optflag,
                char *buffer,
                int length,
                bool dhcpv6)
{
        IF_NOT_UDHCPC6(bool dhcpv6 = 0;)
        struct option_set *existing;
        char *allocated = NULL;

        if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_BIN) {
                const char *end;
                allocated = xstrdup(buffer); /* more than enough */
                end = hex2bin(allocated, buffer, 255);
                if (errno)
                        bb_error_msg_and_die("malformed hex string '%s'", buffer);
                length = end - allocated;
                buffer = allocated;
        }
#if ENABLE_FEATURE_UDHCP_RFC3397
        if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_DNS_STRING) {
                /* reuse buffer and length for RFC1035-formatted string */
                allocated = buffer = (char *)dname_enc(NULL, 0, buffer, &length);
        }
#endif

        existing = udhcp_find_option(*opt_list, optflag->code);
        if (!existing) {
                struct option_set *new, **curr;

                /* make a new option */
                log2("attaching option %02x to list", optflag->code);
                new = xmalloc(sizeof(*new));
                if (!dhcpv6) {
                        new->data = xmalloc(length + OPT_DATA);
                        new->data[OPT_CODE] = optflag->code;
                        new->data[OPT_LEN] = length;
                        memcpy(new->data + OPT_DATA, buffer, length);
                } else {
                        new->data = xmalloc(length + D6_OPT_DATA);
                        new->data[D6_OPT_CODE] = optflag->code >> 8;
                        new->data[D6_OPT_CODE + 1] = optflag->code & 0xff;
                        new->data[D6_OPT_LEN] = length >> 8;
                        new->data[D6_OPT_LEN + 1] = length & 0xff;
                        memcpy(new->data + D6_OPT_DATA, buffer,
                                        length);
                }

                curr = opt_list;
                while (*curr && (*curr)->data[OPT_CODE] < optflag->code)
                        curr = &(*curr)->next;

                new->next = *curr;
                *curr = new;
                goto ret;
        }

        if (optflag->flags & OPTION_LIST) {
                unsigned old_len;

                /* add it to an existing option */
                log2("attaching option %02x to existing member of list", optflag->code);
                old_len = existing->data[OPT_LEN];
                if (old_len + length < 255) {
                        /* actually 255 is ok too, but adding a space can overlow it */

                        existing->data = xrealloc(existing->data, OPT_DATA + 1 + old_len + length);
// So far dhcp_optflags[] has no OPTION_STRING[_HOST] | OPTION_LIST items
#if 0
                        if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_STRING
                         || (optflag->flags & OPTION_TYPE_MASK) == OPTION_STRING_HOST
                        ) {
                                /* add space separator between STRING options in a list */
                                existing->data[OPT_DATA + old_len] = ' ';
                                old_len++;
                        }
#endif

                        memcpy(existing->data + OPT_DATA + old_len, buffer, length);
                        existing->data[OPT_LEN] = old_len + length;
                } /* else, ignore the data, we could put this in a second option in the future */
        } /* else, ignore the new data */

 ret:
        free(allocated);
}

int FAST_FUNC udhcp_str2optset(const char *const_str, void *arg,
                const struct dhcp_optflag *optflags, const char *option_strings,
                bool dhcpv6)
{
        struct option_set **opt_list = arg;
        char *opt;
        char *str;
        const struct dhcp_optflag *optflag;
        struct dhcp_optflag userdef_optflag;
        unsigned optcode;
        int retval;
        /* IP_PAIR needs 8 bytes, STATIC_ROUTES needs 9 max */
        char buffer[9] ALIGNED(4);
        uint16_t *result_u16 = (uint16_t *) buffer;
        uint32_t *result_u32 = (uint32_t *) buffer;

        /* Cheat, the only *const* str possible is "" */
        str = (char *) const_str;
        opt = strtok(str, " \t=:");
        if (!opt)
                return 0;

        optcode = bb_strtou(opt, NULL, 0);
        if (!errno && optcode < 255) {
                /* Raw (numeric) option code.
                 * Initially assume binary (hex-str), but if "str" or 'str'
                 * is seen later, switch to STRING.
                 */
                userdef_optflag.flags = OPTION_BIN;
                userdef_optflag.code = optcode;
                optflag = &userdef_optflag;
        } else {
                optflag = &optflags[udhcp_option_idx(opt, option_strings)];
        }

        /* Loop to handle OPTION_LIST case, else execute just once */
        retval = 0;
        do {
                int length;
                char *val;

                if (optflag->flags == OPTION_BIN) {
                        val = strtok(NULL, ""); /* do not split "'q w e'" */
                        trim(val);
                } else
                        val = strtok(NULL, ", \t");
                if (!val)
                        break;

                length = dhcp_option_lengths[optflag->flags & OPTION_TYPE_MASK];
                retval = 0;
                opt = buffer; /* new meaning for variable opt */

                switch (optflag->flags & OPTION_TYPE_MASK) {
                case OPTION_IP:
                        retval = udhcp_str2nip(val, buffer);
                        break;
                case OPTION_IP_PAIR:
                        retval = udhcp_str2nip(val, buffer);
                        val = strtok(NULL, ", \t/-");
                        if (!val)
                                retval = 0;
                        if (retval)
                                retval = udhcp_str2nip(val, buffer + 4);
                        break;
 case_OPTION_STRING:
                case OPTION_STRING:
                case OPTION_STRING_HOST:
#if ENABLE_FEATURE_UDHCP_RFC3397
                case OPTION_DNS_STRING:
#endif
                        length = strnlen(val, 254);
                        if (length > 0) {
                                opt = val;
                                retval = 1;
                        }
                        break;
//              case OPTION_BOOLEAN: {
//                      static const char no_yes[] ALIGN1 = "no\0yes\0";
//                      buffer[0] = retval = index_in_strings(no_yes, val);
//                      retval++; /* 0 - bad; 1: "no" 2: "yes" */
//                      break;
//              }
                case OPTION_U8:
                        buffer[0] = bb_strtou32(val, NULL, 0);
                        retval = (errno == 0);
                        break;
                /* htonX are macros in older libc's, using temp var
                 * in code below for safety */
                /* TODO: use bb_strtoX? */
                case OPTION_U16: {
                        uint32_t tmp = bb_strtou32(val, NULL, 0);
                        *result_u16 = htons(tmp);
                        retval = (errno == 0 /*&& tmp < 0x10000*/);
                        break;
                }
//              case OPTION_S16: {
//                      long tmp = bb_strtoi32(val, NULL, 0);
//                      *result_u16 = htons(tmp);
//                      retval = (errno == 0);
//                      break;
//              }
                case OPTION_U32: {
                        uint32_t tmp = bb_strtou32(val, NULL, 0);
                        *result_u32 = htonl(tmp);
                        retval = (errno == 0);
                        break;
                }
                case OPTION_S32: {
                        int32_t tmp = bb_strtoi32(val, NULL, 0);
                        *result_u32 = htonl(tmp);
                        retval = (errno == 0);
                        break;
                }
                case OPTION_STATIC_ROUTES: {
                        /* Input: "a.b.c.d/m" */
                        /* Output: mask(1 byte),pfx(0-4 bytes),gw(4 bytes) */
                        unsigned mask;
                        char *slash = strchr(val, '/');
                        if (slash) {
                                *slash = '\0';
                                retval = udhcp_str2nip(val, buffer + 1);
                                buffer[0] = mask = bb_strtou(slash + 1, NULL, 10);
                                val = strtok(NULL, ", \t/-");
                                if (!val || mask > 32 || errno)
                                        retval = 0;
                                if (retval) {
                                        length = ((mask + 7) >> 3) + 5;
                                        retval = udhcp_str2nip(val, buffer + (length - 4));
                                }
                        }
                        break;
                }
                case OPTION_BIN:
                        /* Raw (numeric) option code. Is it a string? */
                        if (val[0] == '"' || val[0] == '\'') {
                                char delim = val[0];
                                char *end = last_char_is(val + 1, delim);
                                if (end) {
                                        *end = '\0';
                                        val++;
                                        userdef_optflag.flags = OPTION_STRING;
                                        goto case_OPTION_STRING;
                                }
                        }
                        /* No: hex-str option, handled in attach_option() */
                        opt = val;
                        retval = 1;
                        break;
                default:
                        break;
                }

                if (retval)
                        attach_option(opt_list, optflag, opt, length, dhcpv6);
        } while (retval && (optflag->flags & OPTION_LIST));

        return retval;
}

/* note: ip is a pointer to an IPv6 in network order, possibly misaliged */
int FAST_FUNC sprint_nip6(char *dest, /*const char *pre,*/ const uint8_t *ip)
{
        char hexstrbuf[16 * 2];
        bin2hex(hexstrbuf, (void*)ip, 16);
        return sprintf(dest, /* "%s" */
                "%.4s:%.4s:%.4s:%.4s:%.4s:%.4s:%.4s:%.4s",
                /* pre, */
                hexstrbuf + 0 * 4,
                hexstrbuf + 1 * 4,
                hexstrbuf + 2 * 4,
                hexstrbuf + 3 * 4,
                hexstrbuf + 4 * 4,
                hexstrbuf + 5 * 4,
                hexstrbuf + 6 * 4,
                hexstrbuf + 7 * 4
        );
}