ossp-pkg/adns/adns_internal.h
1.7
/*
* internal.h
* - declarations of private objects with external linkage (adns__*)
* - definitons of internal macros
* - comments regarding library data structures
*/
/*
* This file is
* Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
*
* It is part of adns, which is
* Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
* Copyright (C) 1999-2000 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
/* get rid of assertions -- rse */
#define NDEBUG 1
#include "adns_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 "adns_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_MAXLABEL 63
#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), in which case it is the
* absolute time when we will close the connection.
*/
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: */
#define ctype_whitespace(c) ((c)==' ' || (c)=='\n' || (c)=='\t')
#define ctype_digit(c) ((c)>='0' && (c)<='9')
#define ctype_alpha(c) (((c) >= 'a' && (c) <= 'z') || ((c) >= 'A' && (c) <= 'Z'))
#define ctype_822special(c) (strchr("()<>@,;:\\\".[]",(c)) != 0)
#define ctype_domainunquoted(c) (ctype_alpha(c) || ctype_digit(c) || (strchr("-_/+",c) != 0))
#define errno_resources(e) ((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) )
/* Misc */
extern void _adns_timevaladd(struct timeval *tv_io, long ms);
#endif
