rlm_isc_dhcp.c

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/*
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or (at
 *   your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/**
 * $Id: 156523385ff662b0a595433bba588c0f9ac2e3a8 $
 * @file rlm_isc_dhcp.c
 * @brief Read ISC DHCP configuration files
 *
 * @copyright 2019 The FreeRADIUS server project
 * @copyright 2019 Alan DeKok (aland@freeradius.org)
 */
RCSID("$Id: 156523385ff662b0a595433bba588c0f9ac2e3a8 $")
 
#include <freeradius-devel/server/base.h>
#include <freeradius-devel/server/module_rlm.h>
#include <freeradius-devel/dhcpv4/dhcpv4.h>
#include <freeradius-devel/util/debug.h>
#include <freeradius-devel/util/skip.h>
 
 
static fr_dict_t const *dict_dhcpv4;
 
extern fr_dict_autoload_t rlm_isc_dhcp_dict[];
fr_dict_autoload_t rlm_isc_dhcp_dict[] = {
        { .out = &dict_dhcpv4, .proto = "dhcpv4" },
        DICT_AUTOLOAD_TERMINATOR
};
 
static fr_dict_attr_t const *attr_client_hardware_address;
static fr_dict_attr_t const *attr_your_ip_address;
static fr_dict_attr_t const *attr_client_identifier;
static fr_dict_attr_t const *attr_server_name;
static fr_dict_attr_t const *attr_boot_filename;
static fr_dict_attr_t const *attr_server_ip_address;
static fr_dict_attr_t const *attr_server_identifier;
 
extern fr_dict_attr_autoload_t rlm_isc_dhcp_dict_attr[];
fr_dict_attr_autoload_t rlm_isc_dhcp_dict_attr[] = {
        { .out = &attr_client_hardware_address, .name = "Client-Hardware-Address", .type = FR_TYPE_ETHERNET, .dict = &dict_dhcpv4},
        { .out = &attr_your_ip_address, .name = "Your-IP-Address", .type = FR_TYPE_IPV4_ADDR, .dict = &dict_dhcpv4},
        { .out = &attr_client_identifier, .name = "Client-Identifier", .type = FR_TYPE_OCTETS, .dict = &dict_dhcpv4},
        { .out = &attr_server_name, .name = "Server-Host-Name", .type = FR_TYPE_STRING, .dict = &dict_dhcpv4},
        { .out = &attr_boot_filename, .name = "Boot-Filename", .type = FR_TYPE_STRING, .dict = &dict_dhcpv4},
        { .out = &attr_server_ip_address, .name = "Server-IP-Address", .type = FR_TYPE_IPV4_ADDR, .dict = &dict_dhcpv4},
        { .out = &attr_server_identifier, .name = "Server-Identifier", .type = FR_TYPE_IPV4_ADDR, .dict = &dict_dhcpv4},
 
        DICT_AUTOLOAD_TERMINATOR
};
 
typedef struct rlm_isc_dhcp_info_s rlm_isc_dhcp_info_t;
 
#define NO_SEMICOLON    (0)
#define YES_SEMICOLON   (1)
#define MAYBE_SEMICOLON (2)
 
/*
 *      Define a structure for our module configuration.
 *
 *      These variables do not need to be in a structure, but it's
 *      a lot cleaner to do so, and a pointer to the structure can
 *      be used as the instance handle.
 */
typedef struct {
        char const              *filename;
        bool                    debug;
        bool                    pedantic;
        rlm_isc_dhcp_info_t     *head;
 
        /*
         *      While "host" blocks can appear anywhere, their
         *      definitions are global.  We use these hashes for
         *      dedup, and for assigning IP addresses in the `recv`
         *      section.  We still need to have host hashes in the
         *      subsections, so that we can apply options from the
         *      bottom up.
         */
        fr_hash_table_t         *hosts_by_ether;        //!< by MAC address
        fr_hash_table_t         *hosts_by_uid;          //!< by client identifier
} rlm_isc_dhcp_t;
 
/*
 *      A mapping of configuration file names to internal variables.
 */
static const conf_parser_t module_config[] = {
        { FR_CONF_OFFSET_FLAGS("filename", CONF_FLAG_FILE_READABLE | CONF_FLAG_REQUIRED | CONF_FLAG_NOT_EMPTY, rlm_isc_dhcp_t, filename) },
        { FR_CONF_OFFSET("debug", rlm_isc_dhcp_t, debug) },
        { FR_CONF_OFFSET("pedantic", rlm_isc_dhcp_t, pedantic) },
        CONF_PARSER_TERMINATOR
};
 
#define IDEBUG if (state->debug) DEBUG
 
/*
 *      For developer debugging.  Likely not needed
 */
#define DDEBUG(...)
 
/*
 *      The parsing functions return:
 *        <0 on error
 *         0 for "I did nothing"
 *         1 for "I did something"
 *
 *      This pattern allows us to distinguish things like empty files
 *      from full files, and empty subsections from full sections, etc.
 */
 
/**  Holds the state of the current tokenizer
 *
 */
typedef struct {
        rlm_isc_dhcp_t  *inst;          //!< module instance
        FILE            *fp;
        char const      *filename;
        int             lineno;
        char            *line;          //!< where the current line started
 
        int             braces;         //!< how many levels deep we are in a { ... }
        bool            saw_semicolon;  //!< whether we saw a semicolon
        bool            eof;            //!< are we at EOF?
        bool            allow_eof;      //!< do we allow EOF?  (i.e. braces == 0)
        bool            debug;          //!< internal developer debugging
 
        char            *buffer;        //!< read buffer
        size_t          bufsize;        //!< size of read buffer
        char            *ptr;           //!< pointer into read buffer
 
        char            *token;         //!< current token that we parsed
        size_t          token_len;      //!< length of the token
 
        char            string[256];    //!< double quoted strings go here, so we don't mangle the input buffer
} rlm_isc_dhcp_tokenizer_t;
 
 
typedef int (*rlm_isc_dhcp_parse_t)(rlm_isc_dhcp_tokenizer_t *state, rlm_isc_dhcp_info_t *info);
typedef int (*rlm_isc_dhcp_apply_t)(rlm_isc_dhcp_t const *inst, request_t *request, rlm_isc_dhcp_info_t *info);
 
typedef enum rlm_isc_dhcp_type_t {
        ISC_INVALID = 0,                //!< we recognize it, but don't implement it
        ISC_NOOP,                       //!< we don't do anything with it
        ISC_IGNORE,                     //!< we deliberately ignore it
        ISC_GROUP,
        ISC_HOST,
        ISC_SUBNET,
        ISC_OPTION,
        ISC_HARDWARE_ETHERNET,
        ISC_FIXED_ADDRESS,
} rlm_isc_dhcp_type_t;
 
/** Describes the commands that we accept, including it's syntax (i.e. name), etc.
 *
 */
typedef struct {
        char const              *name;
        rlm_isc_dhcp_type_t     type;
        rlm_isc_dhcp_parse_t    parse;
        rlm_isc_dhcp_apply_t    apply;
        int                     max_argc;
} rlm_isc_dhcp_cmd_t;
 
/** Holds information about the thing we parsed.
 *
 *      Note that this parser is forgiving.  We would rather accept
 *      things ISC DHCP doesn't accept, than reject things it accepts.
 *
 *      Since we only implement a tiny portion of it's configuration,
 *      we tend to accept all kinds of things, and then just ignore them.
 */
struct rlm_isc_dhcp_info_s {
        rlm_isc_dhcp_cmd_t const *cmd;
        int                     argc;
        fr_value_box_t          **argv;
 
        rlm_isc_dhcp_info_t     *parent;
        rlm_isc_dhcp_info_t     *next;
        void                    *data;          //!< per-thing parsed data.
 
        /*
         *      Only for things that have sections
         */
        fr_hash_table_t         *hosts_by_ether;  //!< by MAC address
        fr_hash_table_t         *hosts_by_uid;  //!< by client identifier
        fr_pair_list_t          options;        //!< DHCP options
        fr_trie_t               *subnets;
        rlm_isc_dhcp_info_t     *child;
        rlm_isc_dhcp_info_t     **last;         //!< pointer to last child
};
 
static int read_file(rlm_isc_dhcp_t *inst, rlm_isc_dhcp_info_t *parent, char const *filename);
static int parse_section(rlm_isc_dhcp_tokenizer_t *state, rlm_isc_dhcp_info_t *info);
 
static char const *spaces = "                                                                                ";
 
/** Refills the read buffer with one line from the file.
 *
 *      This function also takes care of suppressing blank lines, and
 *      lines which only contain comments.
 */
static int refill(rlm_isc_dhcp_tokenizer_t *state)
{
        char *p;
 
        if (state->eof) return 0;
 
        /*
         *      We've run out of data to parse, reset to the start of
         *      the buffer.
         */
        if (!*state->ptr) state->ptr = state->buffer;
 
redo:
        state->lineno++;
        state->line = state->ptr;
 
        if (!fgets(state->ptr, state->bufsize - (state->ptr - state->buffer), state->fp)) {
                if (feof(state->fp)) {
                        state->eof = true;
                        return 0;
                }
 
                return -1;
        }
 
        /*
         *      Skip leading spaces
         */
        p = state->ptr;
        fr_skip_whitespace(p);
 
        /*
         *      The line is all spaces, OR we've hit a comment.  Go
         *      get more data.
         */
        if (!*p || (*p == '#')) goto redo;
 
        /*
         *      Point to the first non-space data.
         */
        state->ptr = p;
 
        return 1;
}
 
static int skip_spaces(rlm_isc_dhcp_tokenizer_t *state, char *p)
{
        char *start = p;
 
        state->ptr = p;
 
        fr_skip_whitespace(state->ptr);
 
        /*
         *      If we ran out of text on this line, re-fill the
         *      buffer.  Note that refill() also takes care of
         *      suppressing blank lines and comments.  refill() also
         *      takes care of skipping leading spaces, too.
         */
        if (!state->eof && !*state->ptr) {
                int ret;
 
                state->ptr = start;
 
                ret = refill(state);
                if (ret < 0) return -1;
        }
 
        /*
         *      Set the semicolon flag as a "peek
         *      ahead", so that the various other
         *      parsers don't need to check it.
         */
        if (*state->ptr == ';') state->saw_semicolon = true;
 
        return 0;
}
 
 
 
/*
 *      ISC's double quoted strings allow all kinds of extra magic, so
 *      we re-implement string parsing yet again.
 */
static int read_string(rlm_isc_dhcp_tokenizer_t *state)
{
        char *p = state->ptr + 1;
        char *q = state->string;
 
        while (true) {
                if (!*p) {
                        fr_strerror_const("unterminated string");
                        return -1;
                }
 
                if (*p == '"') {
                        p++;
                        if (isspace((uint8_t) *p)) {
                                if (skip_spaces(state, p) < 0) return -1;
                                break;
                        }
                }
 
                if ((size_t) (q - state->string) >= sizeof(state->string) - 1) {
                        fr_strerror_const("string is too long");
                        return -1;
                }
 
                if (*p != '\\') {
                        *(q++) = *(p++);
                        continue;
                }
 
                // @todo - all of ISC's string escapes, e.g. \x...
        }
 
        *q = '\0';
 
        state->token = state->string;
        state->token_len = (q - state->string);
        return 1;
}
 
 
/** Reads one token into state->token
 *
 *      Note that this function *destroys* the input buffer.  So if
 *      you need to read two tokens, you have to save the first one
 *      somewhere *outside* of the input buffer.
 */
static int read_token(rlm_isc_dhcp_tokenizer_t *state, fr_token_t hint, int semicolon, bool allow_rcbrace)
{
        char *p;
 
redo:
        /*
         *      If the buffer is empty, re-fill it.
         */
        if (!*state->ptr) {
                int ret;
 
                ret = refill(state);
                if (ret < 0) return ret;
 
                if (ret == 0) {
                        if (!state->allow_eof) {
                                fr_strerror_const("Unexpected EOF");
                                return -1;
                        }
 
                        return 0;
                }
        }
 
        /*
         *      The previous token may have ended on a space
         *      or semi-colon.  We skip those characters
         *      before looking for the next token.
         */
        while (isspace((uint8_t) *state->ptr) || (*state->ptr == ';') || (*state->ptr == ',')) state->ptr++;
 
        if (!*state->ptr) goto redo;
 
        /*
         *      Start looking for the next token from where we left
         *      off last time.
         */
        state->token = state->ptr;
        state->saw_semicolon = false;
 
        /*
         *      Special-case quoted strings.
         */
        if (state->token[0] == '"') {
                if (hint != T_DOUBLE_QUOTED_STRING) {
                        fr_strerror_printf("Unexpected '\"'");
                        return -1;
                }
 
                return read_string(state);
        }
 
        for (p = state->token; *p != '\0'; p++) {
                /*
                 *      "end of word" character.  It might be allowed
                 *      here, or it might not be.
                 */
                if (*p == ';') {
                        if (semicolon == NO_SEMICOLON) {
                                fr_strerror_const("unexpected ';'");
                                return -1;
                        }
 
                        state->ptr = p;
                        state->saw_semicolon = true;
                        break;
                }
 
                /*
                 *      For lists of things and code definitions.
                 */
                if (*p == ',') {
                        state->ptr = p;
                        break;
                }
 
                /*
                 *      Allow braces / equal as single character
                 *      tokens if they're the first character we saw.
                 *      Otherwise, the characters are "end of word"
                 *      markers/
                 */
                if ((*p == '{') || (*p == '}') || (*p == '=')) {
                        if (p == state->token) p++;
 
                        state->ptr = p;
                        break;
                }
 
                /*
                 *      If we find a comment, we ignore everything
                 *      until the end of the line.
                 */
                if (*p == '#') {
                        *p = '\0';
                        state->ptr = p;
 
                        /*
                         *      Nothing here, get more text
                         */
                        if (state->token == state->ptr) goto redo;
                        break;
                }
 
                /*
                 *      Whitespace, we're done.
                 */
                if (isspace((uint8_t) *p)) {
                        if (skip_spaces(state, p) < 0) return -1;
                        break;
                }
        }
 
        /*
         *      Protect the rest of the code from buffer overflows.
         */
        state->token_len = p - state->token;
 
        if (state->token_len == 0) {
                fr_strerror_const("Failed to find token");
                return -1;
        }
 
        if (state->token_len >= 256) {
                fr_strerror_const("token too large");
                return -1;
        }
 
        /*
         *      Double-check the token against what we were expected
         *      to read.
         */
        if (hint == T_LCBRACE) {
                if (*state->token != '{') {
                        fr_strerror_const("missing '{'");
                        return -1;
                }
 
                if ((size_t) state->braces >= (sizeof(spaces) - 1)) {
                        fr_strerror_const("sections are nested too deep");
                        return -1;
                }
 
                state->braces++;
                return 1;
        }
 
        if (hint == T_RCBRACE) {
                if (*state->token != '}') {
                        fr_strerror_const("missing '}'");
                        return -1;
                }
 
                state->braces--;
                return 1;
        }
 
        /*
         *      If we're inside of a section, we may also allow
         *      right-brace as the first keyword.  In that case, it's
         *      the end of the enclosing section.
         */
        if (*state->token == '}') {
                if (!allow_rcbrace) {
                        fr_strerror_const("unexpected '}'");
                        return -1;
                }
 
                state->braces--;
                return 1;
        }
 
        /*
         *      Don't return left brace if we were looking for a
         *      something else.
         */
        if ((hint == T_BARE_WORD) || (hint == T_DOUBLE_QUOTED_STRING)) {
                if (*state->token == '{') {
                        fr_strerror_const("unexpected '{'");
                        return -1;
                }
        }
 
 
        return 1;
}
 
/** Recursively match subwords inside of a command string.
 *
 */
static int match_subword(rlm_isc_dhcp_tokenizer_t *state, char const *cmd, rlm_isc_dhcp_info_t *info)
{
        int ret;
        fr_type_t type;
        int semicolon = NO_SEMICOLON;
        bool multi = false;
        char *p;
        char const *q;
        char const *next;
        char type_name[64];
 
        fr_skip_whitespace(cmd);
 
        if (!*cmd) return -1;   /* internal error */
 
        /*
         *      Remember the next command.
         */
        next = q = cmd;
        while (*next && !isspace((uint8_t) *next) && (*next != ',')) next++;
        if (!*next) semicolon = YES_SEMICOLON;
 
        /*
         *      Matching an in-line word.
         */
        if (islower((uint8_t) *q)) {
                ret = read_token(state, T_BARE_WORD, semicolon, false);
                if (ret <= 0) return -1;
 
                /*
                 *      Look for a verbatim word.
                 */
                for (p = state->token; p < (state->token + state->token_len); p++, q++) {
                        if (*p != *q) {
                        fail:
                                fr_strerror_printf("Expected '%.*s', got unknown text '%.*s'",
                                                   (int)state->token_len, state->token,
                                                   (int) (next - cmd), cmd);
                                return -1;
                        }
                }
 
                /*
                 *      Matched all of 'q', we're done.
                 */
                if (!*q) {
                        DDEBUG("... WORD %.*s ", state->token_len, state->token);
                        return 1;
                }
 
                /*
                 *      Matched all of this word in 'q', but there are
                 *      more words after this one..  Recurse.
                 */
                if (isspace((uint8_t) *q)) {
                        return match_subword(state, next, info);
                }
 
                /*
                 *      Matched all of 'p', but there's more 'q'.  Fail.
                 *
                 *      e.g. got "foo", but expected "food".
                 */
                goto fail;
        }
 
        /*
         *      SECTION must be the last thing in the command
         */
        if (strcmp(q, "SECTION") == 0) {
                if (q[7] != '\0') return -1; /* internal error */
 
                ret = read_token(state, T_LCBRACE, NO_SEMICOLON, false);
                if (ret <= 0) return ret;
 
                ret = parse_section(state, info);
                if (ret < 0) return ret;
 
                /*
                 *      Empty sections are allowed.
                 */
                return 2;       /* SECTION */
        }
 
        /*
         *      Uppercase words are INTEGER or STRING or IPADDR, which
         *      are FreeRADIUS data types.
         *
         *      We copy the name here because some options allow for
         *      multiple fields.
         */
        p = type_name;
        while (*q && !isspace((uint8_t) *q) && (*q != ',')) {
                if ((p - type_name) >= (int) sizeof(type_name)) return -1; /* internal error */
                *(p++) = tolower((uint8_t) *(q++));
        }
        *p = '\0';
 
        /*
         *      "fixed-address IPADDR," means it can take multiple IP
         *      addresses.
         *
         *      @todo - pre-parse the field and save the strings
         *      somewhere, so that we can create info->argv of the
         *      right size.  Or, just create an array of 2 by default,
         *      and then double it every time we run out... a little
         *      more work, but it doesn't involve further mangling the
         *      parser.
         *
         *      We could likely just manually parse state->ptr, look
         *      until ';' or '\0', and count the words.  That would
         *      work 99% of the time.
         *
         *      @todo - We should also note that the ISC default is to
         *      allow hostnames, in which case it will add all IPs
         *      associated with that hostname, while we will add only
         *      one.  That could likely be fixed, too.
         */
        if (*q == ',') {
                if (q[1]) return -1; /* internal error */
                multi = true;
                semicolon = MAYBE_SEMICOLON;
        }
 
        type = fr_type_from_str(type_name);
        if (type == FR_TYPE_NULL) {
                fr_strerror_printf("unknown data type '%.*s'",
                                   (int) (next - cmd), cmd);
                return -1;      /* internal error */
        }
 
redo_multi:
        /*
         *      We were asked to parse a data type, so instead allow
         *      just about anything.
         *
         *      @todo - if we get fancy, dynamically expand this, too.
         *      ISC doesn't support it, but we can.
         */
        ret = read_token(state, T_DOUBLE_QUOTED_STRING, semicolon, false);
        if (ret <= 0) return ret;
 
        DDEBUG("... DATA %.*s ", state->token_len, state->token);
 
        /*
         *      BOOLs in ISC are "true", "false", or "ignore".
         *
         *      Isn't that smart?  "ignore" means "ignore this option
         *      as if it was commented out".  So we do that.
         *
         *      I sure wish I was smart enough to allow 3 values for a
         *      boolean data type.
         */
        if ((type == FR_TYPE_BOOL) && (state->token_len == 6) &&
            (strcmp(state->token, "ignore") == 0)) {
                talloc_free(info);
                return 2;
        }
 
        /*
         *      Parse the data to its final form.
         */
        info->argv[info->argc] = talloc_zero(info, fr_value_box_t);
 
        ret = fr_value_box_from_str(info, info->argv[info->argc], type, NULL,
                                    state->token, state->token_len, NULL);
        if (ret < 0) return ret;
 
        info->argc++;
 
        if (multi) {
                if (state->saw_semicolon) return 1;
 
                if (info->argc >= info->cmd->max_argc) {
                        fr_strerror_printf("Too many arguments (%d > %d) for command '%s'",
                                           info->argc, info->cmd->max_argc, info->cmd->name);
                        return -1;
                }
 
                goto redo_multi;
        }
 
        /*
         *      No more command to parse, return OK.
         */
        if (!*next) return 1;
 
        /*
         *      Keep matching more things
         */
        return match_subword(state, next, info);
}
 
/*
 *      include FILENAME ;
 */
static int parse_include(rlm_isc_dhcp_tokenizer_t *state, rlm_isc_dhcp_info_t *info)
{
        int ret;
        char pathname[8192];
        char const *sep;
        char const *name = info->argv[0]->vb_strvalue;
 
        IDEBUG("%.*s include %s ;", state->braces, spaces, name);
 
        sep = strrchr(state->filename, '/');
        if (sep) {
                char *p;
 
                strlcpy(pathname, state->filename, sizeof(pathname));
                p = pathname + (sep - state->filename) + 1;
                strlcpy(p, name, sizeof(pathname) - (p - pathname));
 
                name = pathname;
        }
 
        /*
         *      Note that we read the included file into the PARENT's
         *      list.  i.e. as if the file was included in-place.
         */
        ret = read_file(state->inst, info->parent, name);
        if (ret < 0) return ret;
 
        /*
         *      Even if the file was empty, we return "1" to indicate
         *      that we successfully parsed the file.  Returning "0"
         *      would indicate that the parent file was at EOF.
         */
        return 1;
}
 
 
typedef struct {
        uint8_t                 ether[6];
        rlm_isc_dhcp_info_t     *host;
} isc_host_ether_t;
 
static uint32_t host_ether_hash(void const *data)
{
        isc_host_ether_t const *self = data;
 
        return fr_hash(self->ether, sizeof(self->ether));
}
 
static int8_t host_ether_cmp(void const *one, void const *two)
{
        isc_host_ether_t const *a = one;
        isc_host_ether_t const *b = two;
        int ret;
 
        ret = memcmp(a->ether, b->ether, 6);
        return CMP(ret, 0);
}
 
typedef struct {
        fr_value_box_t          *client;
        rlm_isc_dhcp_info_t     *host;
} isc_host_uid_t;
 
static uint32_t host_uid_hash(void const *data)
{
        isc_host_uid_t const *self = data;
 
        return fr_hash(self->client->vb_octets, self->client->vb_length);
}
 
static int8_t host_uid_cmp(void const *one, void const *two)
{
        isc_host_uid_t const *a = one;
        isc_host_uid_t const *b = two;
 
        MEMCMP_RETURN(a, b, client->vb_octets, client->vb_length);
        return 0;
}
 
 
/**     option space name [ [ code width number ] [ length width number ] [ hash size number ] ] ;
 *
 */
static int parse_option_space(UNUSED rlm_isc_dhcp_info_t *parent, UNUSED rlm_isc_dhcp_tokenizer_t *state,
                              UNUSED char *name)
{
        // @todo - register the named option space with inst->option_space
        //         and create inst->option_space
        fr_strerror_const("please implement 'option space name [ [ code width number ] [ length width number ] [ hash size number ] ]'");
        return -1;
}
 
 
/** Parse one type string.
 *
 
 *      boolean
 *      [signed|unsigned] integer [width]
 *              width is 8, 16, or 32
 *      ip-address
 *      ip6-address
 *      text
 *      string
 *      domain-list [compressed]
 *      encapsulate _identifier_
 */
 
#define TYPE_CHECK(name, type) if ((state->token_len == (sizeof(name) - 1)) && (memcmp(state->token, name, sizeof(name) - 1) == 0)) return type
static fr_type_t isc2fr_type(rlm_isc_dhcp_tokenizer_t *state)
{
        TYPE_CHECK("boolean", FR_TYPE_BOOL);
        TYPE_CHECK("integer", FR_TYPE_UINT32);
        TYPE_CHECK("ip-address", FR_TYPE_IPV4_ADDR);
        TYPE_CHECK("ip6-address", FR_TYPE_IPV6_ADDR);
        TYPE_CHECK("text", FR_TYPE_STRING);
        TYPE_CHECK("string", FR_TYPE_OCTETS);
 
        fr_strerror_printf("unknown type '%.*s'", (int)state->token_len, state->token);
        return FR_TYPE_NULL;
}
 
 
/** option new-name code new-code = definition ;
 *
 *      "new-name" can also be SPACE.NAME
 *
 */
static int parse_option_definition(rlm_isc_dhcp_info_t *parent, rlm_isc_dhcp_tokenizer_t *state,
                                   char *name)
{
        int ret;
        char *p;
        fr_type_t type;
        fr_dict_attr_t const *da, *root;
        fr_value_box_t box;
        fr_dict_attr_flags_t flags;
 
        p = strchr(name, '.');
        if (p) {
                fr_strerror_const("cannot (yet) define options in spaces");
        error:
                talloc_free(name);
                return -1;
        }
 
        if (parent != state->inst->head) {
                fr_strerror_const("option definitions cannot be scoped");
                goto error;
        }
 
        /*
         *      Grab the integer code value.
         */
        ret = read_token(state, T_BARE_WORD, NO_SEMICOLON, false);
        if (ret <= 0) {
        error_ret:
                talloc_free(name);
                return ret;
        }
 
        type = FR_TYPE_UINT32;
        ret = fr_value_box_from_str(NULL, &box, type, NULL,
                                    state->token, state->token_len, NULL);
        if (ret < 0) goto error;
 
        /*
         *      Look for '='
         */
        ret = read_token(state, T_BARE_WORD, NO_SEMICOLON, false);
        if (ret <= 0) goto error_ret;
 
        if ((state->token_len != 1) || (state->token[0] != '=')) {
                fr_strerror_printf("expected '=' after code definition got '%.*s'", (int)state->token_len, state->token);
                goto error;
        }
 
        memset(&flags, 0, sizeof(flags));
 
        /*
         *      Data type is:
         *
         *      TYPE
         *      array of TYPE
         *      { TYPE, ... }
         *
         *      Note that it also supports
         *
         *      array of { TYPE, ... }
         */
        ret = read_token(state, T_BARE_WORD, MAYBE_SEMICOLON, false);
        if (ret <= 0) goto error_ret;
 
 
        if ((state->token_len == 5) && (memcmp(state->token, "array", 5) == 0)) {
                flags.array = 1;
 
                ret = read_token(state, T_BARE_WORD, NO_SEMICOLON, false);
                if (ret <= 0) goto error_ret;
 
                if (! ((state->token_len == 2) && (memcmp(state->token, "of", 2) == 0))) {
                        fr_strerror_printf("expected 'array of', not 'array %.*s'",
                                           (int)state->token_len, state->token);
                        goto error;
                }
 
                /*
                 *      Grab the next token.  For now, it MUST have a semicolon
                 */
                ret = read_token(state, T_BARE_WORD, YES_SEMICOLON, false);
                if (ret <= 0) goto error_ret;
        }
 
        if ((state->token_len == 1) && (state->token[0] == '{')) {
                fr_strerror_const("records are not supported in option definition");
                goto error;
        }
 
        /*
         *      This check is needed only because we have
         *      MAYBE_SEMICOLON above.  That's in order to allow
         *      "array of.." statements to product an *array* error,
         *      not a *semicolon* error.
         */
        if (!state->saw_semicolon) {
                fr_strerror_const("expected ';'");
                goto error;
        }
 
        type = isc2fr_type(state);
        if (fr_type_is_null(type)) goto error;
 
        /*
         *      Now that we've parsed everything, look up the name.
         *      We forbid conflicts, but silently allow duplicates.
         */
        da = fr_dict_attr_by_name(NULL, fr_dict_root(dict_dhcpv4), name);
        if (da &&
            ((da->attr != box.vb_uint32) || (da->type != type))) {
                fr_strerror_printf("cannot add different code / type for a pre-existing name '%s'", name);
                goto error;
        }
 
        /*
         *      And look it up by code, too.
         *
         *      We allow multiple attributes of the same code / type,
         *      but with different names.
         */
        root = fr_dict_root(dict_dhcpv4);
        da = fr_dict_attr_child_by_num(root, box.vb_uint32);
        if (da && (da->type != type)) {
                fr_strerror_printf("cannot add different type for a pre-existing code %d", box.vb_uint32);
                goto error;
        }
 
        /*
         *      Add it in.  Note that this function adds it by name
         *      and by code.  So we don't *necessarily* have to do the
         *      name/code checks above.  But doing so allows us to
         *      have better error messages.
         */
        ret = fr_dict_attr_add(fr_dict_unconst(dict_dhcpv4), root, name, box.vb_uint32, type, &flags);
        talloc_free(name);
        if (ret < 0) return ret;
 
        /*
         *      Caller doesn't need to do anything else with the thing
         *      we just parsed.
         */
        return 2;
}
 
static int parse_option(rlm_isc_dhcp_info_t *parent, rlm_isc_dhcp_tokenizer_t *state,
                        fr_dict_attr_t const *da, char *value)
{
        int ret;
        fr_pair_t *vp;
 
        /*
         *      The attribute isn't an array, so it MUST have a
         *      semicolon after it.
         */
        if (!da->flags.array && !state->saw_semicolon) {
                fr_strerror_printf("expected ';' %s", state->ptr);
                return -1;
        }
 
        MEM(vp = fr_pair_afrom_da(parent, da));
 
        /*
         *      Add in the first value.
         */
        ret = fr_pair_value_from_str(vp, value, talloc_strlen(value), NULL, false);
        if (ret < 0) {
                talloc_free(value);
                return ret;
        }
 
        fr_pair_append(&parent->options, vp);
 
        // @todo - print out ISC names...
        IDEBUG("%.*s option %s %s ", state->braces, spaces, da->name, value);
        talloc_free(value);
 
        /*
         *      We've remembered the option in the parent option list.
         *      There's no need to add it to the child list here.
         */
        if (!da->flags.array) return 2;
 
        /*
         *      For "array" types, loop through the remaining tokens.
         */
        while (!state->saw_semicolon) {
                ret = read_token(state, T_DOUBLE_QUOTED_STRING, MAYBE_SEMICOLON, false);
                if (ret <= 0) return ret;
 
                MEM(vp = fr_pair_afrom_da(parent, da));
 
                ret = fr_pair_value_from_str(vp, state->token, state->token_len, NULL, false);
                if (ret < 0) return ret;
 
                fr_pair_append(&parent->options, vp);
 
                // @todo - print out ISC names...
                IDEBUG("%.*s option %s %.*ss ", state->braces, spaces, da->name, (int)state->token_len, state->token);
        }
 
        /*
         *      We've remembered the option in the parent option list.
         *      There's no need to add it to the child list here.
         */
        return 2;
}
 
/** Parse "option" command
 *
 *      In any sane system, commands which do different things should
 *      have different names.  In this syntax, it's all miracles and
 *      unicorns.
 *
 *      option NAME VALUE ;
 *      option new-name code new-code = definition ;
 *
 *      option space name [ [ code width number ] [ length width number ] [ hash size number ] ] ;
 */
static int parse_options(rlm_isc_dhcp_info_t *parent, rlm_isc_dhcp_tokenizer_t *state)
{
        int ret, argc = 0;
        char *argv[2];
        char name[FR_DICT_ATTR_MAX_NAME_LEN + 5];
 
        /*
         *      Since read_token() mashes the input buffer, we have to save the tokens somewhere.
         */
        while (!state->saw_semicolon) {
                ret = read_token(state, T_BARE_WORD, MAYBE_SEMICOLON, false);
                if (ret < 0) return ret;
 
                argv[argc++] = talloc_strndup(parent, state->token, state->token_len);
 
                if (argc == 2) break;
        }
 
        /*
         *      Must have at least two arguments.
         */
        if (argc < 2) {
                fr_strerror_const("unexpected ';'");
                return -1;
        }
 
        /*
         *      Define an option space.
         */
        if (strcmp(argv[0], "space") == 0) {
                talloc_free(argv[0]);
                return parse_option_space(parent, state, argv[1]);
        }
 
        /*
         *      Look up the name.  If the option is defined, then
         *      parse the following options according to the data
         *      type.  Which MAY be a "struct" data type, or an
         *      "array" data type.
         */
        if (state->saw_semicolon || (state->ptr[0] == ',')) {
                fr_dict_attr_t const *da;
 
                da = fr_dict_attr_by_name(NULL, fr_dict_root(dict_dhcpv4), argv[0]);
                if (da) {
                        talloc_free(argv[0]);
                        return parse_option(parent, state, da, argv[1]);
                }
 
                /*
                 *      @todo - nuke this extra step once we have dictionary.isc defined.
                 */
                memcpy(name, "DHCP-", 5);
                strlcpy(name + 5, argv[0], sizeof(name) - 5);
 
                da = fr_dict_attr_by_name(NULL, fr_dict_root(dict_dhcpv4), name);
                if (da) {
                        talloc_free(argv[0]);
                        return parse_option(parent, state, da, argv[1]);
                }
        }
 
        /*
         *      The NAME isn't a known option.
         *
         *      It must be "option NAME code NUMBER = DEFINITION"
         */
        if (strcmp(argv[1], "code") != 0) {
                fr_strerror_printf("unknown option '%s'", argv[0]);
                talloc_free(argv[0]);
                talloc_free(argv[1]);
                return -1;
        }
 
        talloc_free(argv[1]);
        return parse_option_definition(parent, state, argv[0]);
}
 
 
static int match_keyword(rlm_isc_dhcp_info_t *parent, rlm_isc_dhcp_tokenizer_t *state, rlm_isc_dhcp_cmd_t const *tokens, int num_tokens)
{
        int start, end, half;
        int semicolon;
        int ret;
        char const *q = NULL;
        rlm_isc_dhcp_info_t *info;
 
        start = 0;
        end = num_tokens - 1;
        half = -1;
 
        /*
         *      There are no super-short commands.
         */
        if (state->token_len < 4) goto unknown;
 
        /*
         *      Walk over the input token, doing a binary search on
         *      the token list.
         */
        while (start <= end) {
                half = (start + end) / 2;
 
                /*
                 *      Skips a function call, and is better for 99%
                 *      of the situations.  Since there are no 1 or 2
                 *      character keywords, this always works.
                 */
                ret = state->token[0] - tokens[half].name[0];
                if (ret != 0) goto recurse;
 
                ret = state->token[1] - tokens[half].name[1];
                if (ret != 0) goto recurse;
 
                ret = state->token[2] - tokens[half].name[2];
                if (ret != 0) goto recurse;
 
                /*
                 *      Compare all of the strings.
                 */
                ret = strncmp(state->token, tokens[half].name, state->token_len);
 
                /*
                 *      Exact match.  But maybe we have "foo" input,
                 *      and "food" command?
                 */
                if (ret == 0) {
                        char c = tokens[half].name[state->token_len];
 
                        /*
                         *      The token exactly matches the command.
                         */
                        if (!c || isspace((uint8_t) c)) {
                                q = &(tokens[half].name[state->token_len]);
                                break;
                        }
 
                        /*
                         *      The token is "foo", but the command is
                         *      "food".  Go search the lower half of
                         *      the command table.
                         */
                        ret = -1;
                }
 
        recurse:
                /*
                 *      Token is smaller than the command we checked,
                 *      go check the lower half of the table.
                 */
                if (ret < 0) {
                        end = half - 1;
                } else {
                        start = half + 1;
                }
        }
 
        /*
         *      Nothing matched, it's a failure.
         */
        if (!q) {
        unknown:
                fr_strerror_printf("unknown command '%.*s'", (int)state->token_len, state->token);
                return -1;
        }
 
        fr_assert(half >= 0);
 
        /*
         *      "option" has multiple parse possibilities, so we treat
         *      it specially.
         */
        if (tokens[half].type == ISC_OPTION) {
                return parse_options(parent, state);
        }
 
        /*
         *      Print out more warnings / errors in pedantic mode.
         */
        if (state->inst->pedantic && !tokens[half].parse) {
                if (tokens[half].type == ISC_INVALID) {
                        ERROR("Command '%.*s' is not supported.",
                              (int)state->token_len, state->token);
                        return -1;
                }
 
                /*
                 *      Print out WARNING messages only in debug mode.
                 *      We don't need to spam the main log file every
                 *      time the server starts.
                 */
                if (DEBUG_ENABLED) {
                        if (tokens[half].type == ISC_NOOP) {
                                WARN("Command '%.*s' is not yet implemented.",
                                     (int)state->token_len, state->token);
                        }
 
                        if (tokens[half].type == ISC_IGNORE) {
                                WARN("Ignoring command '%.*s'.  It is not relevant.",
                                     (int)state->token_len, state->token);
                        }
                }
        }
 
        semicolon = YES_SEMICOLON; /* default to always requiring this */
 
        DDEBUG("... TOKEN %.*s ", (int)state->token_len, state->token);
 
        info = talloc_zero(parent, rlm_isc_dhcp_info_t);
        fr_pair_list_init(&info->options);
        if (tokens[half].max_argc) {
                info->argv = talloc_zero_array(info, fr_value_box_t *, tokens[half].max_argc);
        }
 
        /*
         *      Remember which command we parsed.
         */
        info->parent = parent;
        info->cmd = &tokens[half];
        info->last = &(info->child);
 
        /*
         *      There's more to this command,
         *      go parse that, too.
         */
        if (isspace((uint8_t) *q)) {
                if (state->saw_semicolon) goto unexpected;
 
                ret = match_subword(state, q, info);
                if (ret <= 0) return ret;
 
                /*
                 *      SUBSECTION must be at the end
                 */
                if (ret == 2) semicolon = NO_SEMICOLON;
        }
 
        /*
         *      *q must be empty at this point.
         */
        if ((semicolon == NO_SEMICOLON) && state->saw_semicolon) {
        unexpected:
                fr_strerror_const("unexpected ';'");
                talloc_free(info);
                return -1;
        }
 
        if ((semicolon == YES_SEMICOLON) && !state->saw_semicolon) {
                fr_strerror_const("missing ';'");
                talloc_free(info);
                return -1;
        }
 
        // @todo - print out the thing we parsed
 
        /*
         *      Call the "parse" function which should do
         *      validation, etc.
         */
        if (tokens[half].parse) {
                ret = tokens[half].parse(state, info);
                if (ret <= 0) {
                        talloc_free(info);
                        return ret;
                }
 
                /*
                 *      The parse function took care of
                 *      remembering the "info" structure.  So
                 *      we don't add it to the parent list.
                 *
                 *      This process ensures that for some
                 *      things (e.g. hosts and subnets), we
                 *      have have O(1) lookups instead of
                 *      O(N).
                 *
                 *      It also means that the *rest* of the
                 *      commands we parse are in a relatively
                 *      tiny list, which makes the O(N)
                 *      processing of it fairly minor.
                 */
                if (ret == 2) return 1;
        }
 
        /*
         *      Add the parsed structure to the tail of the
         *      current list.  Note that this portion adds
         *      only ONE command at a time.
         */
        *(parent->last) = info;
        parent->last = &(info->next);
 
        /*
         *      It's a match, and it's OK.
         */
        return 1;
}
 
/** host NAME { ... }
 *
 *      Hosts are global, and are keyed by MAC `hardware ethernet`, and by
 *      `client-identifier`.
 */
static int parse_host(rlm_isc_dhcp_tokenizer_t *state, rlm_isc_dhcp_info_t *info)
{
        isc_host_ether_t *my_ether, *old_ether;
        isc_host_uid_t *my_uid, *old_uid;
        rlm_isc_dhcp_info_t *ether, *child, *parent;
        fr_pair_t *vp;
 
        ether = NULL;
        my_uid = NULL;
 
        /*
         *      A host MUST have at least one "hardware ethernet" in
         *      it.
         */
        for (child = info->child; child != NULL; child = child->next) {
                if (child->cmd->type == ISC_HARDWARE_ETHERNET) {
                        if (ether) {
                                fr_strerror_const("cannot have two 'hardware ethernet' entries in a 'host'");
                                return -1;
                        }
 
                        ether = child;
                }
        }
 
        if (!ether) {
                fr_strerror_printf("host %s does not contain a 'hardware ethernet' entry",
                                   info->argv[0]->vb_strvalue);
                return -1;
        }
 
        /*
         *      Point directly to the ethernet address.
         */
        my_ether = talloc_zero(info, isc_host_ether_t);
        memcpy(my_ether->ether, &(ether->argv[0]->vb_ether), sizeof(my_ether->ether));
        my_ether->host = info;
 
        /*
         *      We can't have duplicate ethernet addresses for hosts.
         */
        old_ether = fr_hash_table_find(state->inst->hosts_by_ether, my_ether);
        if (old_ether) {
                fr_strerror_printf("'host %s' and 'host %s' contain duplicate 'hardware ethernet' fields",
                                   info->argv[0]->vb_strvalue, old_ether->host->argv[0]->vb_strvalue);
                talloc_free(my_ether);
                return -1;
        }
 
        /*
         *      Insert into the ether hashes.
         */
        if (!fr_hash_table_insert(state->inst->hosts_by_ether, my_ether)) {
                fr_strerror_printf("Failed inserting 'host %s' into hash table",
                                   info->argv[0]->vb_strvalue);
                talloc_free(my_ether);
                return -1;
        }
 
        /*
         *      The 'host' entry might not have a client identifier option.
         */
        vp = fr_pair_find_by_da(&info->options, NULL, attr_client_identifier);
        if (vp) {
                my_uid = talloc_zero(info, isc_host_uid_t);
                my_uid->client = &vp->data;
                my_uid->host = info;
 
                old_uid = fr_hash_table_find(state->inst->hosts_by_uid, my_uid);
                if (old_uid) {
                        fr_strerror_printf("'host %s' and 'host %s' contain duplicate 'option client-identifier' fields",
                                           info->argv[0]->vb_strvalue, old_uid->host->argv[0]->vb_strvalue);
                fail:
                        (void) fr_hash_table_delete(state->inst->hosts_by_ether, my_ether);
                        talloc_free(my_uid);
                        return -1;
                }
 
                if (!fr_hash_table_insert(state->inst->hosts_by_uid, my_uid)) {
                        fr_strerror_printf("Failed inserting 'host %s' into hash table",
                                           info->argv[0]->vb_strvalue);
                        goto fail;
                }
        }
 
        /*
         *      The host doesn't have a parent, that's fine..
         *
         *      It typically should tho...
         */
        if (!info->parent) return 2;
 
        parent = info->parent;
 
        /*
         *      Add the host to the *parents* hash table.  That way
         *      when we apply the parent, we can look up the host in
         *      its hash table.  And avoid the O(N) issue of having
         *      thousands of "host" entries in the parent->child list.
         */
        if (!parent->hosts_by_ether) {
                parent->hosts_by_ether = fr_hash_table_alloc(parent, host_ether_hash, host_ether_cmp, NULL);
                if (!parent->hosts_by_ether) {
                        return -1;
                }
        }
 
        if (!fr_hash_table_insert(parent->hosts_by_ether, my_ether)) {
                fr_strerror_printf("Failed inserting 'host %s' into hash table",
                                   info->argv[0]->vb_strvalue);
                return -1;
        }
 
        /*
         *      If we have a UID, insert into the UID hashes.
         */
        if (my_uid) {
                if (!parent->hosts_by_uid) {
                        parent->hosts_by_uid = fr_hash_table_alloc(parent, host_uid_hash, host_uid_cmp, NULL);
                        if (!parent->hosts_by_uid) {
                                return -1;
                        }
                }
 
                if (!fr_hash_table_insert(parent->hosts_by_uid, my_uid)) {
                        (void) fr_hash_table_remove(parent->hosts_by_ether, my_ether); /* remove and don't free */
                        fr_strerror_printf("Failed inserting 'host %s' into hash table",
                                           info->argv[0]->vb_strvalue);
                        return -1;
                }
        }
 
        IDEBUG("%.*s host %s { ... }", state->braces, spaces, info->argv[0]->vb_strvalue);
 
        /*
         *      We've remembered the host in the parent hosts hash.
         *      There's no need to add it to the child list here.
         */
        return 2;
}
 
/** subnet IPADDR netmask MASK { ... }
 *
 */
static int parse_subnet(rlm_isc_dhcp_tokenizer_t *state, rlm_isc_dhcp_info_t *info)
{
        rlm_isc_dhcp_info_t *parent;
        int ret, bits;
        uint32_t netmask = info->argv[1]->vb_ipv4addr;
 
        /*
         *      Check if argv[1] is a valid netmask
         */
        if (netmask & (~netmask >> 1)) {
                fr_strerror_printf("invalid netmask '%pV'", info->argv[1]);
                return -1;
        }
 
        /*
         *      192.168.2.1/16 is wrong.
         */
        if ((info->argv[0]->vb_ipv4addr & netmask) != info->argv[0]->vb_ipv4addr) {
                fr_strerror_printf("subnet '%pV' does not match netmask '%pV'", info->argv[0], info->argv[1]);
                return -1;
        }
 
        /*
         *      Get number of bits set in netmask.
         */
        netmask = netmask - ((netmask >> 1) & 0x55555555);
        netmask = (netmask & 0x33333333) + ((netmask >> 2) & 0x33333333);
        netmask = (netmask + (netmask >> 4)) & 0x0F0F0F0F;
        netmask = netmask + (netmask >> 8);
        netmask = netmask + (netmask >> 16);
        bits = netmask & 0x0000003F;
 
        parent = info->parent;
        if (parent->subnets) {
                rlm_isc_dhcp_info_t *old;
 
                /*
                 *      Duplicate or overlapping "subnet" entries aren't allowed.
                 */
                old = fr_trie_lookup_by_key(parent->subnets, &(info->argv[0]->vb_ipv4addr), bits);
                if (old) {
                        fr_strerror_printf("subnet %pV netmask %pV' overlaps with existing subnet", info->argv[0], info->argv[1]);
                        return -1;
 
                }
        } else {
                parent->subnets = fr_trie_alloc(parent, NULL, NULL);
                if (!parent->subnets) return -1;
        }
 
        /*
         *      Add the subnet to the *parents* trie.  That way when
         *      we apply the parent, we can look up the subnet in its
         *      trie.  And avoid the O(N) issue of having thousands of
         *      "subnet" entries in the parent->child list.
         */
 
        ret = fr_trie_insert_by_key(parent->subnets, &(info->argv[0]->vb_ipv4addr), bits, info);
        if (ret < 0) {
                fr_strerror_printf("Failed inserting 'subnet %pV netmask %pV' into trie",
                                   info->argv[0], info->argv[1]);
                return -1;
        }
 
        /*
         *      @todo - if there's no 'option subnet-mask', add one
         *      from the netmask given here.  If there is an 'option
         *      subnet-mask', then assume that the admin knows what
         *      he's doing, and don't add one.
         */
 
        IDEBUG("%.*s subnet %pV netmask %pV { ... }", state->braces, spaces, info->argv[0], info->argv[1]);
 
        /*
         *      We've remembered the subnet in the parent trie.
         *      There's no need to add it to the child list here.
         */
        return 2;
}
 
static rlm_isc_dhcp_info_t *get_host(request_t *request, fr_hash_table_t *hosts_by_ether, fr_hash_table_t *hosts_by_uid)
{
        fr_pair_t *vp;
        isc_host_ether_t *ether, my_ether;
        rlm_isc_dhcp_info_t *host = NULL;
 
        /*
         *      Look up the host first by client identifier.
         *      If that doesn't match, use client hardware
         *      address.
         */
        if (hosts_by_uid) {
                vp = fr_pair_find_by_da(&request->request_pairs, NULL, attr_client_identifier);
                if (vp) {
                        isc_host_uid_t *client, my_client;
 
                        my_client.client = &(vp->data);
 
                        client = fr_hash_table_find(hosts_by_uid, &my_client);
                        if (client) {
                                host = client->host;
                                goto done;
                        }
                }
        }
 
        vp = fr_pair_find_by_da(&request->request_pairs, NULL, attr_client_hardware_address);
        if (!vp) return NULL;
 
        memcpy(&my_ether.ether, vp->vp_ether, sizeof(my_ether.ether));
 
        ether = fr_hash_table_find(hosts_by_ether, &my_ether);
        if (!ether) return NULL;
 
        host = ether->host;
 
done:
        /*
         *      @todo - check "fixed-address".  This host entry should
         *      match ONLY if one of the addresses matches the network
         *      on which the client is booting.  OR if there's no
         *      'fixed-address' field.  OR if there's no 'yiaddr' in
         *      the request.
         */
 
        return host;
}
 
 
static int add_option_by_da(rlm_isc_dhcp_info_t *info, fr_dict_attr_t const *da)
{
        fr_pair_t *vp;
 
        if (!info->parent) return -1; /* internal error */
 
        MEM(vp = fr_pair_afrom_da(info->parent, da));
 
        /* TLS error buffer is checked */
        if (unlikely(fr_value_box_copy(vp, &(vp->data), info->argv[0]) < 0)) {
                talloc_free(vp);
                return -1;
        }
 
        fr_pair_append(&info->parent->options, vp);
 
        talloc_free(info);
        return 2;
}
 
#define member_size(type, member) sizeof(((type *)0)->member)
 
/** filename STRING
 *
 */
static int parse_filename(UNUSED rlm_isc_dhcp_tokenizer_t *state, rlm_isc_dhcp_info_t *info)
{
        if (info->argv[0]->vb_length > member_size(dhcp_packet_t, file)) {
                fr_strerror_const("filename is too long");
                return -1;
        }
 
        return add_option_by_da(info, attr_boot_filename);
}
 
/** server-name STRING
 *
 */
static int parse_server_name(UNUSED rlm_isc_dhcp_tokenizer_t *state, rlm_isc_dhcp_info_t *info)
{
        if (info->argv[0]->vb_length > member_size(dhcp_packet_t, sname)) {
                fr_strerror_const("server name is too long");
                return -1;
        }
 
        return add_option_by_da(info, attr_server_name);
}
 
/** server-identifier IPADDR
 *
 *
 *      This is really "option dhcp-server-identifier IPADDR"
 *      But whatever
 */
static int parse_server_identifier(UNUSED rlm_isc_dhcp_tokenizer_t *state, rlm_isc_dhcp_info_t *info)
{
        return add_option_by_da(info, attr_server_identifier);
}
 
/** next-server IPADDR
 *
 */
static int parse_next_server(UNUSED rlm_isc_dhcp_tokenizer_t *state, rlm_isc_dhcp_info_t *info)
{
        return add_option_by_da(info, attr_server_ip_address);
}
 
/*
 *  When a client is to be booted, its boot parameters are determined
 *  by consulting that client’s host declaration (if any), and then
 *  consulting any class declarations matching the client, followed by
 *  the pool, subnet and shared-network declarations for the IP
 *  address assigned to the client. Each of these declarations itself
 *  appears within a lexical scope, and all declarations at less
 *  specific lexical scopes are also consulted for client option
 *  declarations. Scopes are never considered twice, and if parameters
 *  are declared in more than one scope, the parameter declared in the
 *  most specific scope is the one that is used.
 *
 *  When dhcpd tries to find a host declaration for a client, it first
 *  looks for a host declaration which has a fixed-address declaration
 *  that lists an IP address that is valid for the subnet or shared
 *  network on which the client is booting. If it doesn’t find any
 *  such entry, it tries to find an entry which has no fixed-address
 *  declaration.
 */
 
/** Apply fixed IPs
 *
 */
static int apply_fixed_ip(rlm_isc_dhcp_t const *inst, request_t *request)
{
        rlm_isc_dhcp_info_t *host, *info;
        fr_pair_t *vp;
        fr_pair_t *yiaddr;
 
        /*
         *      If there's already a fixed IP, don't do anything
         */
        yiaddr = fr_pair_find_by_da(&request->reply_pairs, NULL, attr_your_ip_address);
        if (yiaddr) return 0;
 
        host = get_host(request, inst->hosts_by_ether, inst->hosts_by_uid);
        if (!host) return 0;
 
        /*
         *      Find a "fixed-address" sub-statement.
         */
        for (info = host->child; info != NULL; info = info->next) {
                if (!info->cmd) return -1; /* internal error */
 
                /*
                 *      Skip complex statements
                 */
                if (info->child) continue;
 
                if (info->cmd->type != ISC_FIXED_ADDRESS) continue;
 
                MEM(vp = fr_pair_afrom_da(request->reply_ctx, attr_your_ip_address));
 
                if (unlikely(fr_value_box_copy(vp, &(vp->data), info->argv[0]) < 0)) {
                        RPEDEBUG("Failed assigning Your-IP-Address");
                        return -1;
                }
                fr_pair_append(&request->reply_pairs, vp);
 
                /*
                 *      If we've found a fixed IP, then tell
                 *      the parent to stop iterating over
                 *      children.
                 */
                return 2;
        }
 
        return 0;
}
 
/** Apply all rules *except* fixed IP
 *
 */
static int apply(rlm_isc_dhcp_t const *inst, request_t *request, rlm_isc_dhcp_info_t *head)
{
        int ret, child_ret;
        rlm_isc_dhcp_info_t *info;
        fr_pair_t *yiaddr;
 
        ret = 0;
        yiaddr = fr_pair_find_by_da(&request->reply_pairs, NULL, attr_your_ip_address);
 
        /*
         *      First, apply any "host" options
         */
        if (head->hosts_by_ether) {
                rlm_isc_dhcp_info_t *host = NULL;
 
                host = get_host(request, head->hosts_by_ether, head->hosts_by_uid);
                if (!host) goto subnet;
 
                /*
                 *      Apply any options in the "host" section.
                 */
                child_ret = apply(inst, request, host);
                if (child_ret < 0) return child_ret;
                if (child_ret == 1) ret = 1;
        }
 
subnet:
        /*
         *      Look in the trie for matching subnets, and apply any
         *      subnets that match.
         */
        if (head->subnets && yiaddr) {
                info = fr_trie_lookup_by_key(head->subnets, &yiaddr->vp_ipv4addr, 32);
                if (!info) goto recurse;
 
                child_ret = apply(inst, request, info);
                if (child_ret < 0) return child_ret;
                if (child_ret == 1) ret = 1;
        }
 
recurse:
        for (info = head->child; info != NULL; info = info->next) {
                if (!info->cmd) return -1; /* internal error */
 
                if (!info->cmd->apply) continue;
 
                child_ret = info->cmd->apply(inst, request, info);
                if (child_ret < 0) return child_ret;
                if (child_ret == 0) continue;
 
                ret = 1;
        }
 
        /*
         *      Now that our children have added options, see if we
         *      can add some, too.
         */
        if (!fr_pair_list_empty(&head->options)) {
                fr_pair_t *vp = NULL;
 
                /*
                 *      Walk over the input list, adding the options
                 *      only if they don't already exist in the reply.
                 *
                 *      Yes, we know that this is O(R*P*D), complexity
                 *      is (reply VPs * option VPs * depth of options).
                 *
                 *      Unless we make the code a lot smarter, this is
                 *      the best we can do.  Since there are likely
                 *      only a few options (i.e. less than 100), this
                 *      is deemed to be OK.
                 *
                 *      In order to fix this, we would need to sort
                 *      all of the options first, sort the reply VPs,
                 *      then walk over the reply VPs, and look at each
                 *      option list in turn, seeing if there are
                 *      options that match.  This would likely be
                 *      faster.
                 */
                for (vp = fr_pair_list_head(&head->options);
                     vp != NULL;
                     vp = fr_pair_list_next(&head->options, vp)) {
                        fr_pair_t *reply;
 
                        reply = fr_pair_find_by_da(&request->reply_pairs, NULL, vp->da);
                        if (reply) continue;
 
                        /*
                         *      Copy all of the same options to the
                         *      reply.
                         */
                        while (vp) {
                                fr_pair_t *next, *copy;
 
                                copy = fr_pair_copy(request->reply_ctx, vp);
                                if (!copy) return -1;
 
                                fr_pair_append(&request->reply_pairs, copy);
 
                                next = fr_pair_list_next(&head->options, vp);
                                if (!next) break;
                                if (next->da != vp->da) break;
 
                                vp = fr_pair_list_next(&head->options, vp);
                        }
                }
 
                /*
                 *      We applied some options.
                 */
                ret = 1;
        }
 
        return ret;
}
 
#define isc_not_done    ISC_NOOP, NULL, NULL
#define isc_ignore      ISC_IGNORE, NULL, NULL
#define isc_invalid     ISC_INVALID, NULL, NULL
 
 
/** Table of commands that we allow.
 *
 */
static const rlm_isc_dhcp_cmd_t commands[] = {
        { "abandon-lease-time INTEGER",         isc_not_done, 1},
        { "adaptive-lease-time-threshold INTEGER", isc_not_done, 1},
        { "allow-booting BOOL",                 isc_not_done, 1}, // boolean can be true, false or ignore
        { "allow-bootp BOOL",                   isc_not_done, 1}, // boolean can be true, false or ignore
        { "always-broadcast BOOL",              isc_not_done, 1},
        { "always-reply-rfc1048 BOOL",          isc_not_done, 1}, // boolean can be true, false or ignore
        { "authoritative",                      isc_not_done, 0},
        { "bind-local-address6 BOOL",           isc_ignore,   1}, // boolean can be true, false or ignore
        { "boot-unknown-clients BOOL",          isc_not_done, 1}, // boolean can be true, false or ignore
        { "check-secs-byte-order BOOL",         isc_not_done, 1}, // boolean can be true, false or ignore
        { "class STRING SECTION",                       isc_invalid,  1}, // put systems into different classes
        { "client-updates BOOL",                isc_not_done, 1}, // boolean can be true, false or ignore
        { "ddns-domainname STRING",             isc_not_done, 1}, // text string
        { "ddns-dual-stack-mixed-mode BOOL",    isc_not_done, 1}, // boolean can be true, false or ignore
        { "ddns-guard-id-must-match BOOL",      isc_not_done, 1}, // boolean can be true, false or ignore
        { "ddns-hostname STRING",               isc_not_done, 1}, // text string
        { "ddns-local-address4 IPADDR",         isc_not_done, 1}, // ipaddr or hostname
        { "ddns-local-address6 IPADDR6",        isc_not_done, 1}, // ipv6 addr
        { "ddns-other-guard-is-dynamic BOOL",   isc_not_done, 1}, // boolean can be true, false or ignore
        { "ddns-rev-domainname STRING",         isc_not_done, 1}, // text string
        { "ddns-ttl UINT32",                    isc_not_done, 1}, // Lease time interval
        { "ddns-update-style STRING,",          isc_not_done, 1}, // string options. e.g: opt1, opt2 or opt3 [arg1, ... ]
        { "ddns-updates BOOL",                  isc_not_done, 1}, // boolean can be true, false or ignore
        { "declines BOOL",                      isc_not_done, 1}, // boolean can be true, false or ignore
        { "default-lease-time INTEGER",         isc_not_done, 1},
        { "delayed-ack UINT16",                 isc_invalid,  1},
        { "dhcp-cache-threshold UINT8",         isc_not_done, 1}, // integer uint8_t
        { "dhcpv6-lease-file-name STRING",      isc_ignore,   1}, // text string
        { "dhcpv6-pid-file-name STRING",        isc_ignore,   1}, // text string
        { "dhcpv6-set-tee-times BOOL",          isc_not_done, 1}, // boolean can be true, false or ignore
        { "do-forward-updates BOOL",            isc_not_done, 1}, // boolean can be true, false or ignore
        { "do-reverse-updates BOOL",            isc_not_done, 1}, // boolean can be true, false or ignore
        { "dont-use-fsync BOOL",                isc_not_done, 1}, // boolean can be true, false or ignore
        { "duplicates BOOL",                    isc_not_done, 1}, // boolean can be true, false or ignore
        { "dynamic-bootp BOOL",                 isc_not_done, 1}, // boolean can be true, false or ignore
        { "dynamic-bootp-lease-cutoff UINT32",  isc_not_done, 1}, // Lease time interval
        { "dynamic-bootp-lease-length UINT32",  isc_not_done, 1}, // integer uint32_t
        { "echo-client-id BOOL",                isc_not_done, 1}, // boolean can be true, false or ignore
        { "filename STRING",                    ISC_NOOP, parse_filename, NULL, 1},
        { "fixed-address IPADDR,",              ISC_FIXED_ADDRESS, NULL, NULL, 16},
        { "fqdn-reply BOOL",                    isc_not_done, 1}, // boolean can be true, false or ignore
        { "get-lease-hostnames BOOL",           isc_not_done, 1}, // boolean can be true, false or ignore
        { "group SECTION",                      ISC_GROUP, NULL, NULL, 1},
        { "hardware ethernet ETHER",            ISC_HARDWARE_ETHERNET, NULL, NULL, 1},
        { "host STRING SECTION",                ISC_HOST, parse_host, NULL, 1},
        { "ignore-client-uids BOOL",            isc_not_done, 1}, // boolean can be true, false or ignore
        { "include STRING",                     ISC_NOOP, parse_include, NULL, 1},
        { "infinite-is-reserved BOOL",          isc_not_done, 1}, // boolean can be true, false or ignore
 
        /*
         *      Group configuration into sections?  Why the heck would
         *      we do that?  A flat name space worked for Fortran 77.
         *      It should be good enough for us here.
         */
        { "ldap-base-dn STRING",                isc_ignore,   1}, // text string
        { "ldap-debug-file STRING",             isc_ignore,   1}, // text string
        { "ldap-dhcp-server-cn STRING",         isc_ignore,   1}, // text string
        { "ldap-gssapi-keytab STRING",          isc_ignore,   1}, // text string
        { "ldap-gssapi-principal STRING",       isc_ignore,   1}, // text string
        { "ldap-init-retry STRING",             isc_ignore,   1}, // domain name
        { "ldap-method STRING,",                isc_ignore,   1}, // string options. e.g: opt1, opt2 or opt3 [arg1, ... ]
        { "ldap-password STRING",               isc_ignore,   1}, // text string
        { "ldap-port STRING",                   isc_ignore,   1}, // domain name
        { "ldap-referrals BOOL",                isc_ignore,   1}, // boolean can be true, false or ignore
        { "ldap-server STRING",                 isc_ignore,   1}, // text string
        { "ldap-ssl STRING,",                   isc_ignore,   1}, // string options. e.g: opt1, opt2 or opt3 [arg1, ... ]
        { "ldap-tls-ca-dir STRING",             isc_ignore,   1}, // text string
        { "ldap-tls-ca-file STRING",            isc_ignore,   1}, // text string
        { "ldap-TLS-Certificate STRING",                isc_ignore,   1}, // text string
        { "ldap-tls-ciphers STRING",            isc_ignore,   1}, // text string
        { "ldap-tls-crlcheck STRING,",          isc_ignore,   1}, // string options. e.g: opt1, opt2 or opt3 [arg1, ... ]
        { "ldap-tls-key STRING",                isc_ignore,   1}, // text string
        { "ldap-tls-randfile STRING",           isc_ignore,   1}, // text string
        { "ldap-tls-reqcert STRING,",           isc_ignore,   1}, // string options. e.g: opt1, opt2 or opt3 [arg1, ... ]
        { "ldap-username STRING",               isc_ignore,   1}, // text string
 
        { "lease-file-name STRING",             isc_ignore,   1}, // text string
        { "leasequery BOOL",                    isc_not_done, 1}, // boolean can be true, false or ignore
        { "limit-addrs-per-ia UINT32",          isc_not_done, 1}, // integer uint32_t
        { "limit-prefs-per-ia UINT32",          isc_not_done, 1}, // integer uint32_t
        { "limited-broadcast-address IPADDR",   isc_not_done, 1}, // ipaddr or hostname
        { "local-address IPADDR",               isc_ignore,   1}, // ipaddr or hostname
        { "local-address6 IPADDR6",             isc_ignore,   1}, // ipv6 addr
        { "local-port UINT16",                  isc_ignore,   1}, // integer uint16_t
        { "log-facility STRING,",               isc_ignore,   1}, // string options. e.g: opt1, opt2 or opt3 [arg1, ... ]
        { "log-threshold-high UINT8",           isc_ignore,   1}, // integer uint8_t
        { "log-threshold-low UINT8",            isc_ignore,   1}, // integer uint8_t
        { "match",                              isc_invalid,  0}, // we don't do this at all yet
        { "max-ack-delay UINT32",               isc_invalid,  1},
        { "max-lease-time INTEGER",             isc_not_done, 1},
        { "min-lease-time INTEGER",             isc_not_done, 1},
        { "min-secs UINT8",                     isc_not_done, 1}, // integer uint8_t
        { "next-server IPADDR",                 ISC_NOOP, parse_next_server, NULL, 1}, // ipaddr or hostname
        { "not authoritative",                  isc_not_done, 0},
        { "omapi-key STRING",                   isc_ignore,   1}, // domain name
        { "omapi-port UINT16",                  isc_ignore,   1}, // integer uint16_t
        { "one-lease-per-client BOOL",          isc_not_done, 1}, // boolean can be true, false or ignore
        { "option STRING STRING,",              ISC_OPTION, NULL, NULL, 16},
        { "pid-file-name STRING",               isc_ignore, 1}, // text string
        { "ping-check BOOL",                    isc_not_done, 1}, // boolean can be true, false or ignore
        { "ping-timeout UINT32",                isc_not_done, 1}, // Lease time interval
        { "pool SECTION",                       isc_invalid, 0}, // sub pools
        { "preferred-lifetime UINT32",          isc_not_done, 1}, // Lease time interval
        { "prefix-length-mode STRING,",         isc_not_done, 1}, // string options. e.g: opt1, opt2 or opt3 [arg1, ... ]
        { "range IPADDR IPADDR",                isc_not_done, 2},
        { "release-on-roam BOOL",               isc_not_done, 1}, // boolean can be true, false or ignore
        { "remote-port UINT16",                 isc_ignore,   1}, // integer uint16_t
        { "server-id-check BOOL",               isc_not_done, 1}, // boolean can be true, false or ignore
        { "server-identifier IPADDR",           ISC_NOOP, parse_server_identifier, NULL, 1}, // ipaddr or host name
        { "server-name STRING",                 ISC_NOOP, parse_server_name, NULL, 1}, // text string
        { "shared-network STRING SECTION",      isc_not_done, 1},
        { "site-option-space STRING",           isc_invalid,  1}, // vendor option declaration statement
        { "stash-agent-options BOOL",           isc_not_done, 1}, // boolean can be true, false or ignore
        { "subnet IPADDR netmask IPADDR SECTION", ISC_SUBNET, parse_subnet, NULL, 2},
        { "update-conflict-detection BOOL",     isc_not_done, 1}, // boolean can be true, false or ignore
        { "update-optimization BOOL",           isc_not_done, 1}, // boolean can be true, false or ignore
        { "update-static-leases BOOL",          isc_not_done, 1}, // boolean can be true, false or ignore
        { "use-host-decl-names BOOL",           isc_not_done, 1}, // boolean can be true, false or ignore
        { "use-lease-addr-for-default-route BOOL", isc_not_done, 1}, // boolean can be true, false or ignore
        { "vendor-option-space STRING",         isc_invalid,  1}, // vendor option declaration
};
 
/** Parse a section { ... }
 *
 */
static int parse_section(rlm_isc_dhcp_tokenizer_t *state, rlm_isc_dhcp_info_t *info)
{
        int ret;
        int entries = 0;
 
        /*
         *      We allow "group" inside of "group".  But we don't
         *      allow other sections to nest.
         */
        if (info->cmd->type != ISC_GROUP) {
                rlm_isc_dhcp_info_t *parent;
 
                for (parent = info->parent; parent != NULL; parent = parent->parent) {
                        char const *q;
 
                        if (!parent->cmd) break; /* top level */
 
                        if (parent->cmd != info->cmd) continue;
 
                        /*
                         *      Be gentle to the end user
                         */
                        q = parent->cmd->name;
                        fr_skip_not_whitespace(q);
 
                        fr_strerror_printf("cannot nest '%.*s' statements",
                                           (int) (q - parent->cmd->name), parent->cmd->name);
                        return -1;
                }
        }
 
        IDEBUG("%.*s {", state->braces - 1, spaces); /* "braces" was already incremented */
        state->allow_eof = false; /* can't have EOF in the middle of a section */
 
        while (true) {
                ret = read_token(state, T_BARE_WORD, YES_SEMICOLON, true);
                if (ret < 0) return ret;
                if (ret == 0) break;
 
                /*
                 *      End of section is allowed here.
                 */
                if (*state->token == '}') break;
 
                ret = match_keyword(info, state, commands, NUM_ELEMENTS(commands));
                if (ret < 0) return ret;
                if (ret == 0) break;
 
                entries = 1;
        }
 
        state->allow_eof = (state->braces == 0);
 
        IDEBUG("%.*s }", state->braces, spaces);
 
        return entries;
}
 
/** Open a file and read it into a parent.
 *
 */
static int read_file(rlm_isc_dhcp_t *inst, rlm_isc_dhcp_info_t *parent, char const *filename)
{
        int ret;
        FILE *fp;
        rlm_isc_dhcp_tokenizer_t state;
        rlm_isc_dhcp_info_t **last = parent->last;
        char buffer[8192];
 
        /*
         *      Read the file line by line.
         *
         *      The configuration file format is based off of
         *      keywords, so we write a simple parser to check that.
         */
        fp = fopen(filename, "r");
        if (!fp) {
                fr_strerror_printf("Error opening filename %s: %s", filename, fr_syserror(errno));
                return -1;
        }
 
        memset(&state, 0, sizeof(state));
        state.inst = inst;
        state.fp = fp;
        state.filename = filename;
        state.buffer = buffer;
        state.bufsize = sizeof(buffer);
        state.lineno = 0;
 
        state.braces = 0;
        state.ptr = buffer;
        state.token = NULL;
 
        state.debug = inst->debug;
        state.allow_eof = true;
 
        /*
         *      Tell the state machine that the buffer is empty.
         */
        *state.ptr = '\0';
 
        while (true) {
                ret = read_token(&state, T_BARE_WORD, YES_SEMICOLON, false);
                if (ret < 0) {
                fail:
                        fr_strerror_printf("Failed reading %s:[%d] - %s",
                                           filename, state.lineno,
                                           fr_strerror());
                        fclose(fp);
                        return ret;
                }
                if (ret == 0) break;
 
                /*
                 *      This will automatically re-fill the buffer,
                 *      and find a matching token.
                 */
                ret = match_keyword(parent, &state, commands, NUM_ELEMENTS(commands));
                if (ret < 0) goto fail;
                if (ret == 0) break;
        }
 
        fclose(fp);
 
        /*
         *      The input "last" pointer didn't change, so we didn't
         *      read anything.
         */
        if (!*last) return 0;
 
        return 1;
}
 
static int mod_instantiate(module_inst_ctx_t const *mctx)
{
        rlm_isc_dhcp_t          *inst = talloc_get_type_abort(mctx->mi->data, rlm_isc_dhcp_t);
        CONF_SECTION            *conf = mctx->mi->conf;
        rlm_isc_dhcp_info_t     *info;
        int                     ret;
 
        MEM(inst->head = info = talloc_zero(inst, rlm_isc_dhcp_info_t));
        fr_pair_list_init(&info->options);
        info->last = &(info->child);
 
        inst->hosts_by_ether = fr_hash_table_alloc(inst, host_ether_hash, host_ether_cmp, NULL);
        if (!inst->hosts_by_ether) return -1;
 
        inst->hosts_by_uid = fr_hash_table_alloc(inst, host_uid_hash, host_uid_cmp, NULL);
        if (!inst->hosts_by_uid) return -1;
 
        ret = read_file(inst, info, inst->filename);
        if (ret < 0) {
                cf_log_err(conf, "%s", fr_strerror());
                return -1;
        }
 
        if (ret == 0) {
                cf_log_warn(conf, "No configuration read from %s", inst->filename);
                return 0;
        }
 
        return 0;
}
 
static unlang_action_t CC_HINT(nonnull) mod_authorize(unlang_result_t *p_result, module_ctx_t const *mctx, request_t *request)
{
        rlm_isc_dhcp_t const    *inst = talloc_get_type_abort_const(mctx->mi->data, rlm_isc_dhcp_t);
        int                     ret;
 
        ret = apply_fixed_ip(inst, request);
        if (ret < 0) RETURN_UNLANG_FAIL;
        if (ret == 0) RETURN_UNLANG_NOOP;
 
        if (ret == 2) RETURN_UNLANG_UPDATED;
 
        RETURN_UNLANG_OK;
}
 
static unlang_action_t CC_HINT(nonnull) mod_post_auth(unlang_result_t *p_result, module_ctx_t const *mctx, request_t *request)
{
        rlm_isc_dhcp_t const    *inst = talloc_get_type_abort_const(mctx->mi->data, rlm_isc_dhcp_t);
        int                     ret;
 
        ret = apply(inst, request, inst->head);
        if (ret < 0) RETURN_UNLANG_FAIL;
        if (ret == 0) RETURN_UNLANG_NOOP;
 
        // @todo - check for subnet mask option.  If none exists, use one from the enclosing network?
 
        RETURN_UNLANG_OK;
}
 
extern module_rlm_t rlm_isc_dhcp;
module_rlm_t rlm_isc_dhcp = {
        .common = {
                .magic          = MODULE_MAGIC_INIT,
                .name           = "isc_dhcp",
                .inst_size      = sizeof(rlm_isc_dhcp_t),
                .config         = module_config,
                .instantiate    = mod_instantiate
        },
        .method_group = {
                .bindings = (module_method_binding_t[]){
                        { .section = SECTION_NAME("recv", CF_IDENT_ANY), .method = mod_authorize },
                        { .section = SECTION_NAME("send", CF_IDENT_ANY), .method = mod_post_auth },
                        MODULE_BINDING_TERMINATOR
                }
        }
};