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| -rw-r--r-- | adns-0.6/src/internal.h | 705 |
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diff --git a/adns-0.6/src/internal.h b/adns-0.6/src/internal.h new file mode 100644 index 0000000..9e442fe --- /dev/null +++ b/adns-0.6/src/internal.h @@ -0,0 +1,705 @@ +/* + * internal.h + * - declarations of private objects with external linkage (adns__*) + * - definitons of internal macros + * - comments regarding library data structures + */ +/* + * This file is + * Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk> + * + * It is part of adns, which is + * Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk> + * Copyright (C) 1999 Tony Finch <dot@dotat.at> + * + * 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, 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + +#ifndef ADNS_INTERNAL_H_INCLUDED +#define ADNS_INTERNAL_H_INCLUDED + +#include "config.h" +typedef unsigned char byte; + +#include <stdarg.h> +#include <assert.h> +#include <unistd.h> +#include <signal.h> +#include <errno.h> +#include <string.h> + +#include <sys/time.h> + +#include "adns.h" +#include "dlist.h" + +/* Configuration and constants */ + +#define MAXSERVERS 5 +#define MAXSORTLIST 15 +#define UDPMAXRETRIES 15 +#define UDPRETRYMS 2000 +#define TCPWAITMS 30000 +#define TCPCONNMS 14000 +#define TCPIDLEMS 30000 +#define MAXTTLBELIEVE (7*86400) /* any TTL > 7 days is capped */ + +#define DNS_PORT 53 +#define DNS_MAXUDP 512 +#define DNS_MAXDOMAIN 255 +#define DNS_HDRSIZE 12 +#define DNS_IDOFFSET 0 +#define DNS_CLASS_IN 1 + +#define DNS_INADDR_ARPA "in-addr", "arpa" + +#define MAX_POLLFDS ADNS_POLLFDS_RECOMMENDED + +typedef enum { + cc_user, + cc_entex, + cc_freq +} consistency_checks; + +typedef enum { + rcode_noerror, + rcode_formaterror, + rcode_servfail, + rcode_nxdomain, + rcode_notimp, + rcode_refused +} dns_rcode; + +/* Shared data structures */ + +typedef union { + adns_status status; + char *cp; + adns_rrtype type; + int i; + struct in_addr ia; + unsigned long ul; +} rr_align; + +typedef struct { + int used, avail; + byte *buf; +} vbuf; + +typedef struct { + adns_state ads; + adns_query qu; + int serv; + const byte *dgram; + int dglen, nsstart, nscount, arcount; + struct timeval now; +} parseinfo; + +typedef struct { + adns_rrtype type; + const char *rrtname; + const char *fmtname; + int rrsz; + + void (*makefinal)(adns_query qu, void *data); + /* Change memory management of *data. + * Previously, used alloc_interim, now use alloc_final. + */ + + adns_status (*convstring)(vbuf *vb, const void *data); + /* Converts the RR data to a string representation in vbuf. + * vbuf will be appended to (it must have been initialised), + * and will not be null-terminated by convstring. + */ + + adns_status (*parse)(const parseinfo *pai, int cbyte, int max, void *store_r); + /* Parse one RR, in dgram of length dglen, starting at cbyte and + * extending until at most max. + * + * The RR should be stored at *store_r, of length qu->typei->rrsz. + * + * If there is an overrun which might indicate truncation, it should set + * *rdstart to -1; otherwise it may set it to anything else positive. + * + * nsstart is the offset of the authority section. + */ + + int (*diff_needswap)(adns_state ads, const void *datap_a, const void *datap_b); + /* Returns !0 if RR a should be strictly after RR b in the sort order, + * 0 otherwise. Must not fail. + */ +} typeinfo; + +typedef struct allocnode { + struct allocnode *next, *back; +} allocnode; + +union maxalign { + byte d[1]; + struct in_addr ia; + long l; + void *p; + void (*fp)(void); + union maxalign *up; +} data; + +typedef struct { + void *ext; + void (*callback)(adns_query parent, adns_query child); + union { + adns_rr_addr ptr_parent_addr; + adns_rr_hostaddr *hostaddr; + } info; +} qcontext; + +struct adns__query { + adns_state ads; + enum { query_tosend, query_tcpw, query_childw, query_done } state; + adns_query back, next, parent; + struct { adns_query head, tail; } children; + struct { adns_query back, next; } siblings; + struct { allocnode *head, *tail; } allocations; + int interim_allocd, preserved_allocd; + void *final_allocspace; + + const typeinfo *typei; + byte *query_dgram; + int query_dglen; + + vbuf vb; + /* General-purpose messing-about buffer. + * Wherever a `big' interface is crossed, this may be corrupted/changed + * unless otherwise specified. + */ + + adns_answer *answer; + /* This is allocated when a query is submitted, to avoid being unable + * to relate errors to queries if we run out of memory. During + * query processing status, rrs is 0. cname is set if + * we found a cname (this corresponds to cname_dgram in the query + * structure). type is set from the word go. nrrs and rrs + * are set together, when we find how many rrs there are. + * owner is set during querying unless we're doing searchlist, + * in which case it is set only when we find an answer. + */ + + byte *cname_dgram; + int cname_dglen, cname_begin; + /* If non-0, has been allocated using . */ + + vbuf search_vb; + int search_origlen, search_pos, search_doneabs; + /* Used by the searching algorithm. The query domain in textual form + * is copied into the vbuf, and _origlen set to its length. Then + * we walk the searchlist, if we want to. _pos says where we are + * (next entry to try), and _doneabs says whether we've done the + * absolute query yet (0=not yet, 1=done, -1=must do straight away, + * but not done yet). If flags doesn't have adns_qf_search then + * the vbuf is initialised but empty and everything else is zero. + */ + + int id, flags, retries; + int udpnextserver; + unsigned long udpsent; /* bitmap indexed by server */ + struct timeval timeout; + time_t expires; /* Earliest expiry time of any record we used. */ + + qcontext ctx; + + /* Possible states: + * + * state Queue child id nextudpserver udpsent tcpfailed + * + * tosend NONE null >=0 0 zero zero + * tosend udpw null >=0 any nonzero zero + * tosend NONE null >=0 any nonzero zero + * + * tcpw tcpw null >=0 irrelevant any any + * + * child childw set >=0 irrelevant irrelevant irrelevant + * child NONE null >=0 irrelevant irrelevant irrelevant + * done output null -1 irrelevant irrelevant irrelevant + * + * Queries are only not on a queue when they are actually being processed. + * Queries in state tcpw/tcpw have been sent (or are in the to-send buffer) + * iff the tcp connection is in state server_ok. + * + * +------------------------+ + * START -----> | tosend/NONE | + * +------------------------+ + * / |\ \ + * too big for UDP / UDP timeout \ \ send via UDP + * send via TCP / more retries \ \ + * when conn'd / desired \ \ + * | | | + * v | v + * +-----------+ +-------------+ + * | tcpw/tcpw | ________ | tosend/udpw | + * +-----------+ \ +-------------+ + * | | | UDP timeout | | + * | | | no more | | + * | | | retries | | + * \ | TCP died | desired | | + * \ \ no more | | | + * \ \ servers | TCP / | + * \ \ to try | timeout / | + * got \ \ v |_ | got + * reply \ _| +------------------+ / reply + * \ | done/output FAIL | / + * \ +------------------+ / + * \ / + * _| |_ + * (..... got reply ....) + * / \ + * need child query/ies / \ no child query + * / \ + * |_ _| + * +---------------+ +----------------+ + * | childw/childw | ----------------> | done/output OK | + * +---------------+ children done +----------------+ + */ +}; + +struct query_queue { adns_query head, tail; }; + +struct adns__state { + adns_initflags iflags; + FILE *diagfile; + int configerrno; + struct query_queue udpw, tcpw, childw, output; + adns_query forallnext; + int nextid, udpsocket, tcpsocket; + vbuf tcpsend, tcprecv; + int nservers, nsortlist, nsearchlist, searchndots, tcpserver, tcprecv_skip; + enum adns__tcpstate { + server_disconnected, server_connecting, + server_ok, server_broken + } tcpstate; + struct timeval tcptimeout; + /* This will have tv_sec==0 if it is not valid. + * It will always be valid if tcpstate _connecting. + * When _ok, it will be nonzero if we are idle + * (ie, tcpw queue is empty) and counting down. + */ + struct sigaction stdsigpipe; + sigset_t stdsigmask; + struct pollfd pollfds_buf[MAX_POLLFDS]; + struct server { + struct in_addr addr; + } servers[MAXSERVERS]; + struct sortlist { + struct in_addr base, mask; + } sortlist[MAXSORTLIST]; + char **searchlist; +}; + +/* From setup.c: */ + +int adns__setnonblock(adns_state ads, int fd); /* => errno value */ + +/* From general.c: */ + +void adns__vdiag(adns_state ads, const char *pfx, adns_initflags prevent, + int serv, adns_query qu, const char *fmt, va_list al); + +void adns__debug(adns_state ads, int serv, adns_query qu, + const char *fmt, ...) PRINTFFORMAT(4,5); +void adns__warn(adns_state ads, int serv, adns_query qu, + const char *fmt, ...) PRINTFFORMAT(4,5); +void adns__diag(adns_state ads, int serv, adns_query qu, + const char *fmt, ...) PRINTFFORMAT(4,5); + +int adns__vbuf_ensure(vbuf *vb, int want); +int adns__vbuf_appendstr(vbuf *vb, const char *data); /* does not include nul */ +int adns__vbuf_append(vbuf *vb, const byte *data, int len); +/* 1=>success, 0=>realloc failed */ +void adns__vbuf_appendq(vbuf *vb, const byte *data, int len); +void adns__vbuf_init(vbuf *vb); +void adns__vbuf_free(vbuf *vb); + +const char *adns__diag_domain(adns_state ads, int serv, adns_query qu, + vbuf *vb, const byte *dgram, int dglen, int cbyte); +/* Unpicks a domain in a datagram and returns a string suitable for + * printing it as. Never fails - if an error occurs, it will + * return some kind of string describing the error. + * + * serv may be -1 and qu may be 0. vb must have been initialised, + * and will be left in an arbitrary consistent state. + * + * Returns either vb->buf, or a pointer to a string literal. Do not modify + * vb before using the return value. + */ + +void adns__isort(void *array, int nobjs, int sz, void *tempbuf, + int (*needswap)(void *context, const void *a, const void *b), + void *context); +/* Does an insertion sort of array which must contain nobjs objects + * each sz bytes long. tempbuf must point to a buffer at least + * sz bytes long. needswap should return !0 if a>b (strictly, ie + * wrong order) 0 if a<=b (ie, order is fine). + */ + +void adns__sigpipe_protect(adns_state); +void adns__sigpipe_unprotect(adns_state); +/* If SIGPIPE protection is not disabled, will block all signals except + * SIGPIPE, and set SIGPIPE's disposition to SIG_IGN. (And then restore.) + * Each call to _protect must be followed by a call to _unprotect before + * any significant amount of code gets to run, since the old signal mask + * is stored in the adns structure. + */ + +/* From transmit.c: */ + +adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r, + const char *owner, int ol, + const typeinfo *typei, adns_queryflags flags); +/* Assembles a query packet in vb. A new id is allocated and returned. + */ + +adns_status adns__mkquery_frdgram(adns_state ads, vbuf *vb, int *id_r, + const byte *qd_dgram, int qd_dglen, int qd_begin, + adns_rrtype type, adns_queryflags flags); +/* Same as adns__mkquery, but takes the owner domain from an existing datagram. + * That domain must be correct and untruncated. + */ + +void adns__querysend_tcp(adns_query qu, struct timeval now); +/* Query must be in state tcpw/tcpw; it will be sent if possible and + * no further processing can be done on it for now. The connection + * might be broken, but no reconnect will be attempted. + */ + +void adns__query_send(adns_query qu, struct timeval now); +/* Query must be in state tosend/NONE; it will be moved to a new state, + * and no further processing can be done on it for now. + * (Resulting state is one of udp/timew, tcpwait/timew (if server not connected), + * tcpsent/timew, child/childw or done/output.) + * __query_send may decide to use either UDP or TCP depending whether + * _qf_usevc is set (or has become set) and whether the query is too + * large. + */ + +/* From query.c: */ + +adns_status adns__internal_submit(adns_state ads, adns_query *query_r, + const typeinfo *typei, vbuf *qumsg_vb, int id, + adns_queryflags flags, struct timeval now, + const qcontext *ctx); +/* Submits a query (for internal use, called during external submits). + * + * The new query is returned in *query_r, or we return adns_s_nomemory. + * + * The query datagram should already have been assembled in qumsg_vb; + * the memory for it is _taken over_ by this routine whether it + * succeeds or fails (if it succeeds, the vbuf is reused for qu->vb). + * + * *ctx is copied byte-for-byte into the query. + * + * When the child query is done, ctx->callback will be called. The + * child will already have been taken off both the global list of + * queries in ads and the list of children in the parent. The child + * will be freed when the callback returns. The parent will have been + * taken off the global childw queue. + * + * The callback should either call adns__query_done, if it is + * complete, or adns__query_fail, if an error has occurred, in which + * case the other children (if any) will be cancelled. If the parent + * has more unfinished children (or has just submitted more) then the + * callback may choose to wait for them - it must then put the parent + * back on the childw queue. + */ + +void adns__search_next(adns_state ads, adns_query qu, struct timeval now); +/* Walks down the searchlist for a query with adns_qf_search. + * The query should have just had a negative response, or not had + * any queries sent yet, and should not be on any queue. + * The query_dgram if any will be freed and forgotten and a new + * one constructed from the search_* members of the query. + * + * Cannot fail (in case of error, calls adns__query_fail). + */ + +void *adns__alloc_interim(adns_query qu, size_t sz); +void *adns__alloc_preserved(adns_query qu, size_t sz); +/* Allocates some memory, and records which query it came from + * and how much there was. + * + * If an error occurs in the query, all the memory from _interim is + * simply freed. If the query succeeds, one large buffer will be made + * which is big enough for all these allocations, and then + * adns__alloc_final will get memory from this buffer. + * + * _alloc_interim can fail (and return 0). + * The caller must ensure that the query is failed. + * + * The memory from _preserved is is kept and transferred into the + * larger buffer - unless we run out of memory, in which case it too + * is freed. When you use _preserved you have to add code to the + * x_nomem error exit case in adns__makefinal_query to clear out the + * pointers you made to those allocations, because that's when they're + * thrown away; you should also make a note in the declaration of + * those pointer variables, to note that they are _preserved rather + * than _interim. If they're in the answer, note it here: + * answer->cname and answer->owner are _preserved. + */ + +void adns__transfer_interim(adns_query from, adns_query to, void *block, size_t sz); +/* Transfers an interim allocation from one query to another, so that + * the `to' query will have room for the data when we get to makefinal + * and so that the free will happen when the `to' query is freed + * rather than the `from' query. + * + * It is legal to call adns__transfer_interim with a null pointer; this + * has no effect. + * + * _transfer_interim also ensures that the expiry time of the `to' query + * is no later than that of the `from' query, so that child queries' + * TTLs get inherited by their parents. + */ + +void *adns__alloc_mine(adns_query qu, size_t sz); +/* Like _interim, but does not record the length for later + * copying into the answer. This just ensures that the memory + * will be freed when we're done with the query. + */ + +void *adns__alloc_final(adns_query qu, size_t sz); +/* Cannot fail, and cannot return 0. + */ + +void adns__makefinal_block(adns_query qu, void **blpp, size_t sz); +void adns__makefinal_str(adns_query qu, char **strp); + +void adns__reset_preserved(adns_query qu); +/* Resets all of the memory management stuff etc. to take account of + * only the _preserved stuff from _alloc_preserved. Used when we find + * an error somewhere and want to just report the error (with perhaps + * CNAME, owner, etc. info), and also when we're halfway through RRs + * in a datagram and discover that we need to retry the query. + */ + +void adns__query_done(adns_query qu); +void adns__query_fail(adns_query qu, adns_status stat); + +/* From reply.c: */ + +void adns__procdgram(adns_state ads, const byte *dgram, int len, + int serv, int viatcp, struct timeval now); +/* This function is allowed to cause new datagrams to be constructed + * and sent, or even new queries to be started. However, + * query-sending functions are not allowed to call any general event + * loop functions in case they accidentally call this. + * + * Ie, receiving functions may call sending functions. + * Sending functions may NOT call receiving functions. + */ + +/* From types.c: */ + +const typeinfo *adns__findtype(adns_rrtype type); + +/* From parse.c: */ + +typedef struct { + adns_state ads; + adns_query qu; + int serv; + const byte *dgram; + int dglen, max, cbyte, namelen; + int *dmend_r; +} findlabel_state; + +void adns__findlabel_start(findlabel_state *fls, adns_state ads, + int serv, adns_query qu, + const byte *dgram, int dglen, int max, + int dmbegin, int *dmend_rlater); +/* Finds labels in a domain in a datagram. + * + * Call this routine first. + * dmend_rlater may be null. ads (and of course fls) may not be. + * serv may be -1, qu may be null - they are for error reporting. + */ + +adns_status adns__findlabel_next(findlabel_state *fls, int *lablen_r, int *labstart_r); +/* Then, call this one repeatedly. + * + * It will return adns_s_ok if all is well, and tell you the length + * and start of successive labels. labstart_r may be null, but + * lablen_r must not be. + * + * After the last label, it will return with *lablen_r zero. + * Do not then call it again; instead, just throw away the findlabel_state. + * + * *dmend_rlater will have been set to point to the next part of + * the datagram after the label (or after the uncompressed part, + * if compression was used). *namelen_rlater will have been set + * to the length of the domain name (total length of labels plus + * 1 for each intervening dot). + * + * If the datagram appears to be truncated, *lablen_r will be -1. + * *dmend_rlater, *labstart_r and *namelen_r may contain garbage. + * Do not call _next again. + * + * There may also be errors, in which case *dmend_rlater, + * *namelen_rlater, *lablen_r and *labstart_r may contain garbage. + * Do not then call findlabel_next again. + */ + +typedef enum { + pdf_quoteok= 0x001 +} parsedomain_flags; + +adns_status adns__parse_domain(adns_state ads, int serv, adns_query qu, + vbuf *vb, parsedomain_flags flags, + const byte *dgram, int dglen, int *cbyte_io, int max); +/* vb must already have been initialised; it will be reset if necessary. + * If there is truncation, vb->used will be set to 0; otherwise + * (if there is no error) vb will be null-terminated. + * If there is an error vb and *cbyte_io may be left indeterminate. + * + * serv may be -1 and qu may be 0 - they are used for error reporting only. + */ + +adns_status adns__parse_domain_more(findlabel_state *fls, adns_state ads, + adns_query qu, vbuf *vb, parsedomain_flags flags, + const byte *dgram); +/* Like adns__parse_domain, but you pass it a pre-initialised findlabel_state, + * for continuing an existing domain or some such of some kind. Also, unlike + * _parse_domain, the domain data will be appended to vb, rather than replacing + * the existing contents. + */ + +adns_status adns__findrr(adns_query qu, int serv, + const byte *dgram, int dglen, int *cbyte_io, + int *type_r, int *class_r, unsigned long *ttl_r, + int *rdlen_r, int *rdstart_r, + int *ownermatchedquery_r); +/* Finds the extent and some of the contents of an RR in a datagram + * and does some checks. The datagram is *dgram, length dglen, and + * the RR starts at *cbyte_io (which is updated afterwards to point + * to the end of the RR). + * + * The type, class, TTL and RRdata length and start are returned iff + * the corresponding pointer variables are not null. type_r, class_r + * and ttl_r may not be null. The TTL will be capped. + * + * If ownermatchedquery_r != 0 then the owner domain of this + * RR will be compared with that in the query (or, if the query + * has gone to a CNAME lookup, with the canonical name). + * In this case, *ownermatchedquery_r will be set to 0 or 1. + * The query datagram (or CNAME datagram) MUST be valid and not truncated. + * + * If there is truncation then *type_r will be set to -1 and + * *cbyte_io, *class_r, *rdlen_r, *rdstart_r and *eo_matched_r will be + * undefined. + * + * qu must obviously be non-null. + * + * If an error is returned then *type_r will be undefined too. + */ + +adns_status adns__findrr_anychk(adns_query qu, int serv, + const byte *dgram, int dglen, int *cbyte_io, + int *type_r, int *class_r, unsigned long *ttl_r, + int *rdlen_r, int *rdstart_r, + const byte *eo_dgram, int eo_dglen, int eo_cbyte, + int *eo_matched_r); +/* Like adns__findrr_checked, except that the datagram and + * owner to compare with can be specified explicitly. + * + * If the caller thinks they know what the owner of the RR ought to + * be they can pass in details in eo_*: this is another (or perhaps + * the same datagram), and a pointer to where the putative owner + * starts in that datagram. In this case *eo_matched_r will be set + * to 1 if the datagram matched or 0 if it did not. Either + * both eo_dgram and eo_matched_r must both be non-null, or they + * must both be null (in which case eo_dglen and eo_cbyte will be ignored). + * The eo datagram and contained owner domain MUST be valid and + * untruncated. + */ + +void adns__update_expires(adns_query qu, unsigned long ttl, struct timeval now); +/* Updates the `expires' field in the query, so that it doesn't exceed + * now + ttl. + */ + +int vbuf__append_quoted1035(vbuf *vb, const byte *buf, int len); + +/* From event.c: */ + +void adns__tcp_broken(adns_state ads, const char *what, const char *why); +/* what and why may be both 0, or both non-0. */ + +void adns__tcp_tryconnect(adns_state ads, struct timeval now); + +void adns__autosys(adns_state ads, struct timeval now); +/* Make all the system calls we want to if the application wants us to. + * Must not be called from within adns internal processing functions, + * lest we end up in recursive descent ! + */ + +void adns__must_gettimeofday(adns_state ads, const struct timeval **now_io, + struct timeval *tv_buf); + +int adns__pollfds(adns_state ads, struct pollfd pollfds_buf[MAX_POLLFDS]); +void adns__fdevents(adns_state ads, + const struct pollfd *pollfds, int npollfds, + int maxfd, const fd_set *readfds, + const fd_set *writefds, const fd_set *exceptfds, + struct timeval now, int *r_r); +int adns__internal_check(adns_state ads, + adns_query *query_io, + adns_answer **answer, + void **context_r); + +void adns__timeouts(adns_state ads, int act, + struct timeval **tv_io, struct timeval *tvbuf, + struct timeval now); +/* If act is !0, then this will also deal with the TCP connection + * if previous events broke it or require it to be connected. + */ + +/* From check.c: */ + +void adns__consistency(adns_state ads, adns_query qu, consistency_checks cc); + +/* Useful static inline functions: */ + +static inline int ctype_whitespace(int c) { return c==' ' || c=='\n' || c=='\t'; } +static inline int ctype_digit(int c) { return c>='0' && c<='9'; } +static inline int ctype_alpha(int c) { + return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'); +} +static inline int ctype_822special(int c) { return strchr("()<>@,;:\\\".[]",c) != 0; } + +static inline int errno_resources(int e) { return e==ENOMEM || e==ENOBUFS; } + +/* Useful macros */ + +#define MEM_ROUND(sz) \ + (( ((sz)+sizeof(union maxalign)-1) / sizeof(union maxalign) ) \ + * sizeof(union maxalign) ) + +#define GETIL_B(cb) (((dgram)[(cb)++]) & 0x0ff) +#define GET_B(cb,tv) ((tv)= GETIL_B((cb))) +#define GET_W(cb,tv) ((tv)=0, (tv)|=(GETIL_B((cb))<<8), (tv)|=GETIL_B(cb), (tv)) +#define GET_L(cb,tv) ( (tv)=0, \ + (tv)|=(GETIL_B((cb))<<24), \ + (tv)|=(GETIL_B((cb))<<16), \ + (tv)|=(GETIL_B((cb))<<8), \ + (tv)|=GETIL_B(cb), \ + (tv) ) + +#endif |