/* $NetBSD: reduce.c,v 1.3.4.2 2024/02/29 11:39:21 martin Exp $ */ /* * Copyright (C) 2017-2022 Internet Systems Consortium, Inc. ("ISC") * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. * * Internet Systems Consortium, Inc. * PO Box 360 * Newmarket, NH 03857 USA * * https://www.isc.org/ * */ #include __RCSID("$NetBSD: reduce.c,v 1.3.4.2 2024/02/29 11:39:21 martin Exp $"); #include "keama.h" #include #include #include #include #include #include #include #include #include static struct element *reduce_equal_expression(struct element *left, struct element *right); static void debug(const char* fmt, ...); /* * boolean_expression :== CHECK STRING | * NOT boolean-expression | * data-expression EQUAL data-expression | * data-expression BANG EQUAL data-expression | * data-expression REGEX_MATCH data-expression | * boolean-expression AND boolean-expression | * boolean-expression OR boolean-expression * EXISTS OPTION-NAME */ struct element * reduce_boolean_expression(struct element *expr) { /* trivial case: already done */ if (expr->type == ELEMENT_BOOLEAN) return expr; /* * From is_boolean_expression */ if (expr->type != ELEMENT_MAP) return NULL; /* check */ if (mapContains(expr, "check")) /* * syntax := { "check": } * semantic: check_collection * on server try to match classes of the collection */ return NULL; /* exists */ if (mapContains(expr, "exists")) { /* * syntax := { "exists": * { "universe": , * "name": } * } * semantic: check universe/code from incoming packet */ struct element *arg; struct element *universe; struct element *name; struct option *option; char result[80]; arg = mapGet(expr, "exists"); if ((arg == NULL) || (arg->type != ELEMENT_MAP)) { debug("can't get exists argument"); return NULL; } universe = mapGet(arg, "universe"); if ((universe == NULL) || (universe->type != ELEMENT_STRING)) { debug("can't get exists option universe"); return NULL; } name = mapGet(arg, "name"); if ((name == NULL) || (name->type != ELEMENT_STRING)) { debug("can't get exists option name"); return NULL; } option = option_lookup_name(stringValue(universe)->content, stringValue(name)->content); if ((option == NULL) || (option->code == 0)) return NULL; if (((local_family == AF_INET) && (strcmp(option->space->name, "dhcp4") != 0)) || ((local_family == AF_INET6) && (strcmp(option->space->name, "dhcp6") != 0))) return NULL; snprintf(result, sizeof(result), "option[%u].exists", option->code); return createString(makeString(-1, result)); } /* variable-exists */ if (mapContains(expr, "variable-exists")) /* * syntax := { "variable-exists": } * semantics: find_binding(scope, name) */ return NULL; /* equal */ if (mapContains(expr, "equal")) { /* * syntax := { "equal": * { "left": , * "right": } * } * semantics: evaluate branches and return true * if same type and same value */ struct element *arg; struct element *left; struct element *right; arg = mapGet(expr, "equal"); if ((arg == NULL) || (arg->type != ELEMENT_MAP)) { debug("can't get equal argument"); return NULL; } left = mapGet(arg, "left"); if (left == NULL) { debug("can't get equal left branch"); return NULL; } right = mapGet(arg, "right"); if (right == NULL) { debug("can't get equal right branch"); return NULL; } return reduce_equal_expression(left, right); } /* not-equal */ if (mapContains(expr, "not-equal")) { /* * syntax := { "not-equal": * { "left": , * "right": } * } * semantics: evaluate branches and return true * if different type or different value */ struct element *arg; struct element *left; struct element *right; struct element *equal; struct string *result; arg = mapGet(expr, "not-equal"); if ((arg == NULL) || (arg->type != ELEMENT_MAP)) { debug("can't get not-equal argument"); return NULL; } left = mapGet(arg, "left"); if (left == NULL) { debug("can't get not-equal left branch"); return NULL; } right = mapGet(arg, "right"); if (right == NULL) { debug("can't get not-equal right branch"); return NULL; } equal = reduce_equal_expression(left, right); if ((equal == NULL) || (equal->type != ELEMENT_STRING)) return NULL; result = makeString(-1, "not ("); concatString(result, stringValue(equal)); appendString(result, ")"); return createString(result); } /* regex-match */ if (mapContains(expr, "regex-match")) /* * syntax := { "regex-match": * { "left": , * "right": } * } * semantics: evaluate branches, compile right as a * regex and apply it to left */ return NULL; /* iregex-match */ if (mapContains(expr, "iregex-match")) /* * syntax := { "regex-match": * { "left": , * "right": } * } * semantics: evaluate branches, compile right as a * case insensistive regex and apply it to left */ return NULL; /* and */ if (mapContains(expr, "and")) { /* * syntax := { "and": * { "left": , * "right": } * } * semantics: evaluate branches, return true * if both are true */ struct element *arg; struct element *left; struct element *right; struct string *result; arg = mapGet(expr, "and"); if ((arg == NULL) || (arg->type != ELEMENT_MAP)) { debug("can't get and argument"); return NULL; } left = mapGet(arg, "left"); if (left == NULL) { debug("can't get and left branch"); return NULL; } right = mapGet(arg, "right"); if (right == NULL) { debug("can't get and right branch"); return NULL; } left = reduce_boolean_expression(left); if ((left == NULL) || (left->type != ELEMENT_STRING)) return NULL; right = reduce_boolean_expression(right); if ((right == NULL) || (right->type != ELEMENT_STRING)) return NULL; result = makeString(-1, "("); concatString(result, stringValue(left)); appendString(result, ") and ("); concatString(result, stringValue(right)); appendString(result, ")"); return createString(result); } /* or */ if (mapContains(expr, "or")) { /* * syntax := { "or": * { "left": , * "right": } * } * semantics: evaluate branches, return true * if any is true */ struct element *arg; struct element *left; struct element *right; struct string *result; arg = mapGet(expr, "or"); if ((arg == NULL) || (arg->type != ELEMENT_MAP)) { debug("can't get or argument"); return NULL; } left = mapGet(arg, "left"); if (left == NULL) { debug("can't get or left branch"); return NULL; } right = mapGet(arg, "right"); if (right == NULL) { debug("can't get or right branch"); return NULL; } left = reduce_boolean_expression(left); if ((left == NULL) || (left->type != ELEMENT_STRING)) return NULL; right = reduce_boolean_expression(right); if ((right == NULL) || (right->type != ELEMENT_STRING)) return NULL; result = makeString(-1, "("); concatString(result, stringValue(left)); appendString(result, ") or ("); concatString(result, stringValue(right)); appendString(result, ")"); return createString(result); } /* not */ if (mapContains(expr, "not")) { /* * syntax := { "not": } * semantic: evaluate its branch and return its negation */ struct element *arg; struct string *result; arg = mapGet(expr, "not"); if (arg == NULL) { debug("can't get not argument"); return NULL; } arg = reduce_boolean_expression(arg); if ((arg == NULL) || (arg->type != ELEMENT_STRING)) return NULL; result = makeString(-1, "not ("); concatString(result, stringValue(arg)); appendString(result, ")"); return createString(result); } /* known */ if (mapContains(expr, "known")) /* * syntax := { "known": null } * semantics: client is known, i.e., has a matching * host declaration (aka reservation in Kea) */ return NULL; /* static */ if (mapContains(expr, "static")) /* * syntax := { "static": null } * semantics: lease is static (doesn't exist in Kea) */ return NULL; return NULL; } /* * data_expression :== SUBSTRING LPAREN data-expression COMMA * numeric-expression COMMA * numeric-expression RPAREN | * CONCAT LPAREN data-expression COMMA * data-expression RPAREN * SUFFIX LPAREN data_expression COMMA * numeric-expression RPAREN | * LCASE LPAREN data_expression RPAREN | * UCASE LPAREN data_expression RPAREN | * OPTION option_name | * HARDWARE | * PACKET LPAREN numeric-expression COMMA * numeric-expression RPAREN | * V6RELAY LPAREN numeric-expression COMMA * data-expression RPAREN | * STRING | * colon_separated_hex_list */ struct element * reduce_data_expression(struct element *expr) { /* trivial case: already done */ if (expr->type == ELEMENT_STRING) return expr; /* * From is_data_expression */ if (expr->type != ELEMENT_MAP) return NULL; /* substring */ if (mapContains(expr, "substring")) { /* * syntax := { "substring": * { "expression": , * "offset": , * "length": } * } * semantic: evaluate arguments, if the string is * shorter than offset return "" else return substring */ struct element *arg; struct element *string; struct element *offset; struct element *length; struct string *result; int64_t off; int64_t len; char buf[80]; arg = mapGet(expr, "substring"); if ((arg == NULL) || (arg->type != ELEMENT_MAP)) { debug("can't get substring argument"); return NULL; } string = mapGet(arg, "expression"); if (string == NULL) { debug("can't get substring expression"); return NULL; } offset = mapGet(arg, "offset"); if (offset == NULL) { debug("can't get substring offset"); return NULL; } length = mapGet(arg, "length"); if (length == NULL) { debug("can't get substring length"); return NULL; } /* can't be a literal as it was evaluated before */ string = reduce_data_expression(string); if ((string == NULL) || (string->type != ELEMENT_STRING)) return NULL; offset = reduce_numeric_expression(offset); if ((offset == NULL) || (offset->type != ELEMENT_INTEGER)) return NULL; off = intValue(offset); if (off < 0) { debug("substring with a negative offset (%lld)", (long long)off); return NULL; } length = reduce_numeric_expression(length); if ((length == NULL) || (length->type != ELEMENT_INTEGER)) return NULL; len = intValue(length); if (len < 0) { debug("substring with a negative length (%lld)", (long long)len); return NULL; } result = makeString(-1, "substring("); concatString(result, stringValue(string)); snprintf(buf, sizeof(buf), ",%u,%u)", (unsigned)off, (unsigned)len); appendString(result, buf); return createString(result); } /* suffix */ if (mapContains(expr, "suffix")) { /* * syntax := { "suffix": * { "expression": , * "length": } * } * semantic: evaluate arguments, if the string is * shorter than length return it else return suffix */ struct element *arg; struct element *string; struct element *length; struct string *result; int64_t len; char buf[80]; arg = mapGet(expr, "suffix"); if ((arg == NULL) || (arg->type != ELEMENT_MAP)) { debug("can't get suffix argument"); return NULL; } string = mapGet(arg, "expression"); if (string == NULL) { debug("can't get suffix expression"); return NULL; } length = mapGet(arg, "length"); if (length == NULL) { debug("can't get suffix length"); return NULL; } /* can't be a literal as it was evaluated before */ string = reduce_data_expression(string); if ((string == NULL) || (string->type != ELEMENT_STRING)) return NULL; length = reduce_numeric_expression(length); if ((length == NULL) || (length->type != ELEMENT_INTEGER)) return NULL; len = intValue(length); if (len < 0) { debug("suffix with a negative length (%lld)", (long long)len); return NULL; } result = makeString(-1, "substring("); concatString(result, stringValue(string)); snprintf(buf, sizeof(buf), ",-%u,all)", (unsigned)len); appendString(result, buf); return createString(result); } /* lowercase */ if (mapContains(expr, "lowercase")) /* * syntax := { "lowercase": } * semantic: evaluate its argument and apply tolower to * its content */ return NULL; /* uppercase */ if (mapContains(expr, "uppercase")) /* * syntax := { "uppercase": } * semantic: evaluate its argument and apply toupper to * its content */ return NULL; /* option */ if (mapContains(expr, "option")) { /* * syntax := { "option": * { "universe": , * "name": } * } * semantic: get universe/code option from incoming packet */ struct element *arg; struct element *universe; struct element *name; struct option *option; char result[80]; arg = mapGet(expr, "option"); if ((arg == NULL) || (arg->type != ELEMENT_MAP)) { debug("can't get option argument"); return NULL; } universe = mapGet(arg, "universe"); if ((universe == NULL) || (universe->type != ELEMENT_STRING)) { debug("can't get option universe"); return NULL; } name = mapGet(arg, "name"); if ((name == NULL) || (name->type != ELEMENT_STRING)) { debug("can't get option name"); return NULL; } option = option_lookup_name(stringValue(universe)->content, stringValue(name)->content); if ((option == NULL) || (option->code == 0)) return NULL; if (((local_family == AF_INET) && (strcmp(option->space->name, "dhcp4") != 0)) || ((local_family == AF_INET6) && (strcmp(option->space->name, "dhcp6") != 0))) return NULL; snprintf(result, sizeof(result), "option[%u].hex", option->code); return createString(makeString(-1, result)); } /* hardware */ if (mapContains(expr, "hardware")) { /* * syntax := { "hardware": null } * semantic: get mac type and address from incoming packet */ struct string *result; if (local_family != AF_INET) { debug("get hardware for DHCPv6"); return NULL; } result = makeString(-1, "concat(substring(pkt4.htype,-1,all),pkt4.mac)"); return createString(result); } /* hw-type */ if (mapContains(expr, "hw-type")) { /* * ADDED * syntax := { "hw-type": null } * semantic: get mac type from incoming packet */ struct string *result; if (local_family != AF_INET) { debug("get hw-type for DHCPv6"); return NULL; } result = makeString(-1, "substring(pkt4.htype,-1,all)"); return createString(result); } /* hw-address */ if (mapContains(expr, "hw-address")) { /* * ADDED * syntax := { "hw-address": null } * semantic: get mac address from incoming packet */ struct string *result; if (local_family != AF_INET) { debug("get hw-address for DHCPv6"); return NULL; } result = makeString(-1, "pkt4.mac"); return createString(result); } /* const-data */ if (mapContains(expr, "const-data")) { /* * syntax := { "const-data": } * semantic: embedded string value */ struct element *arg; arg = mapGet(expr, "const-data"); if ((arg == NULL) || (arg->type != ELEMENT_STRING)) { debug("can't get const-data argument"); return NULL; } return createString(stringValue(arg)); } /* packet */ if (mapContains(expr, "packet")) /* * syntax := { "packet": * { "offset": , * "length": } * } * semantic: return the selected substring of the incoming * packet content */ return NULL; /* concat */ if (mapContains(expr, "concat")) { /* * syntax := { "concat": * { "left": , * "right": } * } * semantic: evaluate arguments and return the concatenation */ struct element *arg; struct element *left; struct element *right; struct string *result; arg = mapGet(expr, "concat"); if ((arg == NULL) || (arg->type != ELEMENT_MAP)) { debug("can't get concat argument"); return NULL; } left = mapGet(arg, "left"); if (left == NULL) { debug("can't get concat left branch"); return NULL; } right = mapGet(arg, "right"); if (right == NULL) { debug("can't get concat right branch"); return NULL; } /* left is a literal case */ if (left->type == ELEMENT_STRING) { /* can't be a literal as it was evaluated before */ right = reduce_data_expression(right); if ((right == NULL) || (right->type != ELEMENT_STRING)) return NULL; result = makeString(-1, "concat("); concatString(result, quote(stringValue(left))); appendString(result, ", "); concatString(result, stringValue(right)); appendString(result, ")"); return createString(result); } left = reduce_data_expression(left); if ((left == NULL) || (left->type != ELEMENT_STRING)) return NULL; /* right is a literal case */ if (right->type == ELEMENT_STRING) { /* literal left was handled before */ result = makeString(-1, "concat("); concatString(result, stringValue(left)); appendString(result, ", "); concatString(result, quote(stringValue(right))); appendString(result, ")"); return createString(result); } right = reduce_data_expression(right); if ((right == NULL) || (right->type != ELEMENT_STRING)) return NULL; result = makeString(-1, "concat("); concatString(result, stringValue(left)); appendString(result, ", "); concatString(result, stringValue(right)); appendString(result, ")"); return createString(result); } /* encapsulate */ if (mapContains(expr, "encapsulate")) /* * syntax := { "encapsulate": } * semantic: encapsulate options of the given space */ return NULL; /* encode-int8 */ if (mapContains(expr, "encode-int8")) /* * syntax := { "encode-int8": } * semantic: return a string buffer with the evaluated * number as content */ return NULL; /* encode-int16 */ if (mapContains(expr, "encode-int16")) /* * syntax := { "encode-int16": } * semantic: return a string buffer with the evaluated * number as content */ return NULL; /* encode-int32 */ if (mapContains(expr, "encode-int32")) /* * syntax := { "encode-int32": } * semantic: return a string buffer with the evaluated * number as content */ return NULL; /* gethostbyname */ if (mapContains(expr, "gethostbyname")) /* * syntax := { "gethostbyname": } * semantic: call gethostbyname and return * a binary buffer with addresses */ return NULL; /* binary-to-ascii */ if (mapContains(expr, "binary-to-ascii")) /* * syntax := { "binary-to-ascii": * { "base": , * "width": , * "separator": , * "buffer": } * } * semantic: split the input buffer into int8/16/32 numbers, * output them separated by the given string */ return NULL; /* filename */ if (mapContains(expr, "filename")) /* * syntax := { "filename": null } * semantic: get filename field from incoming DHCPv4 packet */ return NULL; /* server-name */ if (mapContains(expr, "server-name")) /* * syntax := { "server-name": null } * semantic: get server-name field from incoming DHCPv4 packet */ return NULL; /* reverse */ if (mapContains(expr, "reverse")) /* * syntax := { "reverse": * { "width": , * "buffer": } * } * semantic: reverse the input buffer by width chunks of bytes */ return NULL; /* pick-first-value */ if (mapContains(expr, "pick-first-value")) /* * syntax := { "pick-first-value": * [ , ... ] * } * semantic: evaluates expressions and return the first * not null, return null if all are null */ return NULL; /* host-decl-name */ if (mapContains(expr, "host-decl-name")) /* * syntax := { "host-decl-name": null } * semantic: return the name of the matching host * declaration (aka revervation in kea) or null */ return NULL; /* leased-address */ if (mapContains(expr, "leased-address")) /* * syntax := { "leased-address": null } * semantic: return the address of the assigned lease or * log a message */ return NULL; /* config-option */ if (mapContains(expr, "config-option")) /* * syntax := { "config-option": * { "universe": , * "name": } * } * semantic: get universe/code option to send */ return NULL; /* null */ if (mapContains(expr, "null")) { /* * syntax := { "null": null } * semantic: return null */ debug("unexpected null: this expression was not evaluated"); return NULL; } /* gethostname */ if (mapContains(expr, "gethostname")) { /* * syntax := { "gethostname": null } * semantic: return gethostname */ debug("unexpected gethostname: this expression was not " "evaluated"); return NULL; } /* v6relay */ if (mapContains(expr, "v6relay")) { /* * syntax := { "v6relay": * { "relay": , * "relay-option" } * } * semantic: relay is a counter from client, 0 is no-op, * 1 is the relay closest to the client, etc, option * is a dhcp6 option ans is return when found */ struct element *arg; struct element *relay; struct element *universe; struct element *name; struct option *option; int64_t r; char result[100]; if (local_family != AF_INET6) { debug("get v6relay for DHCPv4"); return NULL; } arg = mapGet(expr, "v6relay"); if ((arg == NULL) || (arg->type != ELEMENT_MAP)) { debug("can't get v6relay argument"); return NULL; } relay = mapGet(arg, "relay"); if (relay == NULL) { debug("can't get v6relay relay"); return NULL; } relay = reduce_numeric_expression(relay); if ((relay == NULL) || (relay->type != ELEMENT_INTEGER)) return NULL; r = intValue(relay); if (r < 0) { debug("v6relay called with illegal relay (%lld)", (long long)r); return NULL; } arg = mapGet(arg, "relay-option"); if ((arg == NULL) || (arg->type != ELEMENT_MAP)) { debug("can't get v6relay relay-option"); return NULL; } universe = mapGet(arg, "universe"); if ((universe == NULL) || (universe->type != ELEMENT_STRING)) { debug("can't get v6relay option universe"); NULL; } name = mapGet(arg, "name"); if ((name == NULL) || (name->type != ELEMENT_STRING)) { debug("can't get v6relay option name"); return NULL; } option = option_lookup_name(stringValue(universe)->content, stringValue(name)->content); if ((option == NULL) || (option->code == 0) || (strcmp(option->space->name, "dhcp6") != 0)) return NULL; if (r == 0) snprintf(result, sizeof(result), "option[%u].hex", option->code); else { /* r > MAX_V6RELAY_HOPS means the relay closest to server */ if (r > MAX_V6RELAY_HOPS) r = 0; /* Kea counts from the server, use negative nesting levels to count from the client */ snprintf(result, sizeof(result), "relay6[%d].option[%u].hex", (int)-r, option->code); } return createString(makeString(-1, result)); } return NULL; } struct element * reduce_numeric_expression(struct element *expr) { /* trivial case: already done */ if (expr->type == ELEMENT_INTEGER) return expr; if (expr->type != ELEMENT_MAP) return NULL; /* Kea has no numeric operators... */ return NULL; } static struct element * reduce_equal_expression(struct element *left, struct element *right) { struct string *result; /* * numeric case was handled by evaluation */ if (!is_data_expression(left) || !is_data_expression(right)) return NULL; /* left is a literal case */ if (left->type == ELEMENT_STRING) { /* can't be a literal as it was evaluated before */ right = reduce_data_expression(right); if ((right == NULL) || (right->type != ELEMENT_STRING)) return NULL; result = allocString(); concatString(result, quote(stringValue(left))); appendString(result, " == "); concatString(result, stringValue(right)); return createString(result); } left = reduce_data_expression(left); if ((left == NULL) || (left->type != ELEMENT_STRING)) return NULL; /* right is a literal case */ if (right->type == ELEMENT_STRING) { /* literal left was handled before */ result = allocString(); concatString(result, stringValue(left)); appendString(result, " == "); concatString(result, quote(stringValue(right))); return createString(result); } right = reduce_data_expression(right); if ((right == NULL) || (right->type != ELEMENT_STRING)) return NULL; result = allocString(); concatString(result, stringValue(left)); appendString(result, " == "); concatString(result, stringValue(right)); return createString(result); } static void debug(const char* fmt, ...) { va_list list; va_start(list, fmt); vfprintf(stderr, fmt, list); fprintf(stderr, "\n"); va_end(list); }