/* * 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 * * It is part of adns, which is * Copyright (C) 1997-1999 Ian Jackson * Copyright (C) 1999 Tony Finch * * 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 #include #include #include #include #include #include #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