/*
* event.c
* - event loop core
* - TCP connection management
* - user-visible check/wait and event-loop-related functions
*/
/*
* 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.
*
* $Id: event.c,v 1.2 2003/06/14 13:55:50 tr-ircd Exp $
*/
#include "struct.h"
#include "fileio.h"
#include "internal.h"
#include "fd.h"
#include "h.h"
#include "s_bsd.h"
#include "tvarith.h"
/* TCP connection management. */
static void tcp_close(adns_state ads)
{
int serv;
serv = ads->tcpserver;
fd_close(ads->tcpsocket);
ads->tcpsocket = -1;
ads->tcprecv.used = ads->tcprecv_skip = ads->tcpsend.used = 0;
}
void adns__tcp_broken(adns_state ads, const char *what, const char *why)
{
int serv;
adns_query qu;
assert(ads->tcpstate == server_connecting || ads->tcpstate == server_ok);
serv = ads->tcpserver;
if (what)
adns__warn(ads, serv, 0, "TCP connection failed: %s: %s", what, why);
if (ads->tcpstate == server_connecting) {
/* Counts as a retry for all the queries waiting for TCP. */
for (qu = ads->tcpw.head; qu; qu = qu->next)
qu->retries++;
}
tcp_close(ads);
ads->tcpstate = server_broken;
ads->tcpserver = (serv + 1) % ads->nservers;
}
static void tcp_connected(adns_state ads, struct timeval now)
{
adns_query qu, nqu;
adns__debug(ads, ads->tcpserver, 0, "TCP connected");
ads->tcpstate = server_ok;
for (qu = ads->tcpw.head; qu && ads->tcpstate == server_ok; qu = nqu) {
nqu = qu->next;
assert(qu->state == query_tcpw);
adns__querysend_tcp(qu, now);
}
}
void adns__tcp_tryconnect(adns_state ads, struct timeval now)
{
int r, fd, tries;
struct sockaddr_in addr;
for (tries = 0; tries < ads->nservers; tries++) {
switch (ads->tcpstate) {
case server_connecting:
case server_ok:
case server_broken:
return;
case server_disconnected:
break;
default:
abort();
}
assert(!ads->tcpsend.used);
assert(!ads->tcprecv.used);
assert(!ads->tcprecv_skip);
fd = comm_open(AF_INET, SOCK_STREAM, 0, "adns TCP socket");
if (fd < 0) {
adns__diag(ads, -1, 0, "cannot create TCP socket: %s", strerror(errno));
return;
}
r = adns__setnonblock(ads, fd);
if (r) {
adns__diag(ads, -1, 0, "cannot make TCP socket nonblocking: %s", strerror(r));
fd_close(fd);
return;
}
memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = htons(DNS_PORT);
addr.sin_addr = ads->servers[ads->tcpserver].addr;
r = connect(fd, (const struct sockaddr *) &addr, sizeof(addr));
ads->tcpsocket = fd;
ads->tcpstate = server_connecting;
if (r == 0) {
tcp_connected(ads, now);
return;
}
if (errno == EWOULDBLOCK || errno == EINPROGRESS) {
ads->tcptimeout = now;
timevaladd(&ads->tcptimeout, TCPCONNMS);
return;
}
adns__tcp_broken(ads, "connect", strerror(errno));
ads->tcpstate = server_disconnected;
}
}
/* Timeout handling functions. */
void adns__must_gettimeofday(adns_state ads, const struct timeval **now_io, struct timeval *tv_buf)
{
const struct timeval *now;
int r;
now = *now_io;
if (now)
return;
r = gettimeofday(tv_buf, 0);
if (!r) {
*now_io = tv_buf;
return;
}
adns__diag(ads, -1, 0, "gettimeofday failed: %s", strerror(errno));
adns_globalsystemfailure(ads);
return;
}
static void inter_immed(struct timeval **tv_io, struct timeval *tvbuf)
{
struct timeval *rbuf;
if (!tv_io)
return;
rbuf = *tv_io;
if (!rbuf) {
*tv_io = rbuf = tvbuf;
}
timerclear(rbuf);
}
static void inter_maxto(struct timeval **tv_io, struct timeval *tvbuf, struct timeval maxto)
{
struct timeval *rbuf;
if (!tv_io)
return;
rbuf = *tv_io;
if (!rbuf) {
*tvbuf = maxto;
*tv_io = tvbuf;
} else {
if (timercmp(rbuf, &maxto, >))
*rbuf = maxto;
}
/*fprintf(stderr,"inter_maxto maxto=%ld.%06ld result=%ld.%06ld\n",
* maxto.tv_sec,maxto.tv_usec,(**tv_io).tv_sec,(**tv_io).tv_usec); */
}
static void inter_maxtoabs(struct timeval **tv_io, struct timeval *tvbuf,
struct timeval now, struct timeval maxtime)
{
/* tv_io may be 0 */
ldiv_t dr;
/*fprintf(stderr,"inter_maxtoabs now=%ld.%06ld maxtime=%ld.%06ld\n",
* now.tv_sec,now.tv_usec,maxtime.tv_sec,maxtime.tv_usec); */
if (!tv_io)
return;
maxtime.tv_sec -= (now.tv_sec + 2);
maxtime.tv_usec -= (now.tv_usec - 2000000);
dr = ldiv(maxtime.tv_usec, 1000000);
maxtime.tv_sec += dr.quot;
maxtime.tv_usec -= dr.quot * 1000000;
if (maxtime.tv_sec < 0)
timerclear(&maxtime);
inter_maxto(tv_io, tvbuf, maxtime);
}
static void timeouts_queue(adns_state ads, int act,
struct timeval **tv_io, struct timeval *tvbuf,
struct timeval now, struct query_queue *queue)
{
adns_query qu, nqu;
for (qu = queue->head; qu; qu = nqu) {
nqu = qu->next;
if (!timercmp(&now, &qu->timeout, >)) {
inter_maxtoabs(tv_io, tvbuf, now, qu->timeout);
} else {
if (!act) {
inter_immed(tv_io, tvbuf);
return;
}
LIST_UNLINK(*queue, qu);
if (qu->state != query_tosend) {
adns__query_fail(qu, adns_s_timeout);
} else {
adns__query_send(qu, now);
}
nqu = queue->head;
}
}
}
static void tcp_events(adns_state ads, int act,
struct timeval **tv_io, struct timeval *tvbuf, struct timeval now)
{
adns_query qu, nqu;
for (;;) {
switch (ads->tcpstate) {
case server_broken:
if (!act) {
inter_immed(tv_io, tvbuf);
return;
}
for (qu = ads->tcpw.head; qu; qu = nqu) {
nqu = qu->next;
assert(qu->state == query_tcpw);
if (qu->retries > ads->nservers) {
LIST_UNLINK(ads->tcpw, qu);
adns__query_fail(qu, adns_s_allservfail);
}
}
ads->tcpstate = server_disconnected;
case server_disconnected: /* fall through */
if (!ads->tcpw.head)
return;
if (!act) {
inter_immed(tv_io, tvbuf);
return;
}
adns__tcp_tryconnect(ads, now);
break;
case server_ok:
if (ads->tcpw.head)
return;
if (!ads->tcptimeout.tv_sec) {
assert(!ads->tcptimeout.tv_usec);
ads->tcptimeout = now;
timevaladd(&ads->tcptimeout, TCPIDLEMS);
}
case server_connecting: /* fall through */
if (!act || !timercmp(&now, &ads->tcptimeout, >)) {
inter_maxtoabs(tv_io, tvbuf, now, ads->tcptimeout);
return;
}
{
/* TCP timeout has happened */
switch (ads->tcpstate) {
case server_connecting: /* failed to connect */
adns__tcp_broken(ads, "unable to make connection", "timed out");
break;
case server_ok: /* idle timeout */
tcp_close(ads);
ads->tcpstate = server_disconnected;
return;
default:
abort();
}
}
break;
default:
abort();
}
}
return;
}
void adns__timeouts(adns_state ads, int act,
struct timeval **tv_io, struct timeval *tvbuf, struct timeval now)
{
timeouts_queue(ads, act, tv_io, tvbuf, now, &ads->udpw);
timeouts_queue(ads, act, tv_io, tvbuf, now, &ads->tcpw);
tcp_events(ads, act, tv_io, tvbuf, now);
}
void adns_firsttimeout(adns_state ads,
struct timeval **tv_io, struct timeval *tvbuf, struct timeval now)
{
adns__consistency(ads, 0, cc_entex);
adns__timeouts(ads, 0, tv_io, tvbuf, now);
adns__consistency(ads, 0, cc_entex);
}
void adns_processtimeouts(adns_state ads, const struct timeval *now)
{
struct timeval tv_buf;
adns__consistency(ads, 0, cc_entex);
adns__must_gettimeofday(ads, &now, &tv_buf);
if (now)
adns__timeouts(ads, 1, 0, 0, *now);
adns__consistency(ads, 0, cc_entex);
}
/* fd handling functions. These are the top-level of the real work of
* reception and often transmission.
*/
int adns__pollfds(adns_state ads, struct adns_pollfd pollfds_buf[MAX_POLLFDS])
{
/* Returns the number of entries filled in. Always zeroes revents. */
assert(MAX_POLLFDS == 2);
pollfds_buf[0].fd = ads->udpsocket;
pollfds_buf[0].events = ADNS_POLLIN;
pollfds_buf[0].revents = 0;
switch (ads->tcpstate) {
case server_disconnected:
case server_broken:
return 1;
case server_connecting:
pollfds_buf[1].events = ADNS_POLLOUT;
break;
case server_ok:
pollfds_buf[1].events =
ads->tcpsend.
used ? ADNS_POLLIN | ADNS_POLLOUT | ADNS_POLLPRI : ADNS_POLLIN | ADNS_POLLPRI;
break;
default:
abort();
}
pollfds_buf[1].fd = ads->tcpsocket;
return 2;
}
int adns_processreadable(adns_state ads, int fd, const struct timeval *now)
{
int want, dgramlen, r, udpaddrlen, serv, old_skip;
byte udpbuf[DNS_MAXUDP];
struct sockaddr_in udpaddr;
adns__consistency(ads, 0, cc_entex);
switch (ads->tcpstate) {
case server_disconnected:
case server_broken:
case server_connecting:
break;
case server_ok:
if (fd != ads->tcpsocket)
break;
assert(!ads->tcprecv_skip);
do {
if (ads->tcprecv.used >= ads->tcprecv_skip + 2) {
dgramlen = ((ads->tcprecv.buf[ads->tcprecv_skip] << 8) |
ads->tcprecv.buf[ads->tcprecv_skip + 1]);
if (ads->tcprecv.used >= ads->tcprecv_skip + 2 + dgramlen) {
old_skip = ads->tcprecv_skip;
ads->tcprecv_skip += 2 + dgramlen;
adns__procdgram(ads, ads->tcprecv.buf + old_skip + 2,
dgramlen, ads->tcpserver, 1, *now);
continue;
} else {
want = 2 + dgramlen;
}
} else {
want = 2;
}
ads->tcprecv.used -= ads->tcprecv_skip;
memmove(ads->tcprecv.buf, ads->tcprecv.buf + ads->tcprecv_skip, ads->tcprecv.used);
ads->tcprecv_skip = 0;
if (!adns__vbuf_ensure(&ads->tcprecv, want)) {
r = ENOMEM;
goto xit;
}
assert(ads->tcprecv.used <= ads->tcprecv.avail);
if (ads->tcprecv.used == ads->tcprecv.avail)
continue;
r = read(ads->tcpsocket,
ads->tcprecv.buf + ads->tcprecv.used,
ads->tcprecv.avail - ads->tcprecv.used);
if (r > 0) {
ads->tcprecv.used += r;
} else {
if (r) {
if (errno == EAGAIN || errno == EWOULDBLOCK) {
r = 0;
goto xit;
}
if (errno == EINTR)
continue;
if (errno_resources(errno)) {
r = errno;
goto xit;
}
}
adns__tcp_broken(ads, "read", r ? strerror(errno) : "closed");
}
} while (ads->tcpstate == server_ok);
r = 0;
goto xit;
default:
abort();
}
if (fd == ads->udpsocket) {
for (;;) {
udpaddrlen = sizeof(udpaddr);
r = recvfrom(ads->udpsocket, udpbuf, sizeof(udpbuf), 0,
(struct sockaddr *) &udpaddr, (int *) &udpaddrlen);
if (r < 0) {
if (errno == EAGAIN || errno == EWOULDBLOCK) {
r = 0;
goto xit;
}
if (errno == EINTR)
continue;
if (errno_resources(errno)) {
r = errno;
goto xit;
}
adns__warn(ads, -1, 0, "datagram receive error: %s", strerror(errno));
r = 0;
goto xit;
}
if (udpaddrlen != sizeof(udpaddr)) {
adns__diag(ads, -1, 0,
"datagram received with wrong address length %d"
" (expected %lu)", udpaddrlen, (unsigned long) sizeof(udpaddr));
continue;
}
if (udpaddr.sin_family != AF_INET) {
adns__diag(ads, -1, 0,
"datagram received with wrong protocol family"
" %u (expected %u)", udpaddr.sin_family, AF_INET);
continue;
}
if (ntohs(udpaddr.sin_port) != DNS_PORT) {
adns__diag(ads, -1, 0,
"datagram received from wrong port %u (expected %u)",
ntohs(udpaddr.sin_port), DNS_PORT);
continue;
}
for (serv = 0;
serv < ads->nservers &&
ads->servers[serv].addr.s_addr != udpaddr.sin_addr.s_addr; serv++);
if (serv >= ads->nservers) {
adns__warn(ads, -1, 0,
"datagram received from unknown nameserver %s",
inetntoa((char *) &udpaddr.sin_addr));
continue;
}
adns__procdgram(ads, udpbuf, r, serv, 0, *now);
}
}
r = 0;
xit:
adns__consistency(ads, 0, cc_entex);
return r;
}
int adns_processwriteable(adns_state ads, int fd, const struct timeval *now)
{
int r;
adns__consistency(ads, 0, cc_entex);
switch (ads->tcpstate) {
case server_disconnected:
case server_broken:
break;
case server_connecting:
if (fd != ads->tcpsocket)
break;
assert(ads->tcprecv.used == 0);
assert(ads->tcprecv_skip == 0);
for (;;) {
if (!adns__vbuf_ensure(&ads->tcprecv, 1)) {
r = ENOMEM;
goto xit;
}
r = read(ads->tcpsocket, &ads->tcprecv.buf, 1);
if (r == 0 || (r < 0 && (errno == EAGAIN || errno == EWOULDBLOCK))) {
tcp_connected(ads, *now);
r = 0;
goto xit;
}
if (r > 0) {
adns__tcp_broken(ads, "connect/read", "sent data before first request");
r = 0;
goto xit;
}
if (errno == EINTR)
continue;
if (errno_resources(errno)) {
r = errno;
goto xit;
}
adns__tcp_broken(ads, "connect/read", strerror(errno));
r = 0;
goto xit;
} /* not reached */
case server_ok:
if (fd != ads->tcpsocket)
break;
while (ads->tcpsend.used) {
r = write(ads->tcpsocket, ads->tcpsend.buf, ads->tcpsend.used);
if (r < 0) {
if (errno == EINTR)
continue;
if (errno == EAGAIN || errno == EWOULDBLOCK) {
r = 0;
goto xit;
}
if (errno_resources(errno)) {
r = errno;
goto xit;
}
adns__tcp_broken(ads, "write", strerror(errno));
r = 0;
goto xit;
} else if (r > 0) {
ads->tcpsend.used -= r;
memmove(ads->tcpsend.buf, ads->tcpsend.buf + r, ads->tcpsend.used);
}
}
r = 0;
goto xit;
default:
abort();
}
r = 0;
xit:
adns__consistency(ads, 0, cc_entex);
return r;
}
int adns_processexceptional(adns_state ads, int fd, const struct timeval *now)
{
adns__consistency(ads, 0, cc_entex);
switch (ads->tcpstate) {
case server_disconnected:
case server_broken:
break;
case server_connecting:
case server_ok:
if (fd != ads->tcpsocket)
break;
adns__tcp_broken(ads, "poll/select", "exceptional condition detected");
break;
default:
abort();
}
adns__consistency(ads, 0, cc_entex);
return 0;
}
static void fd_event(adns_state ads, int fd,
int revent, int pollflag,
int maxfd, const fd_set * fds,
int (*func) (adns_state, int fd,
const struct timeval * now), struct timeval now, int *r_r)
{
int r;
if (!(revent & pollflag))
return;
if (fds && !(fd < maxfd && FD_ISSET(fd, fds)))
return;
r = func(ads, fd, &now);
if (r) {
if (r_r) {
*r_r = r;
} else {
adns__diag(ads, -1, 0, "process fd failed after select: %s", strerror(errno));
adns_globalsystemfailure(ads);
}
}
}
void adns__fdevents(adns_state ads,
const struct adns_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 i, fd, revents;
for (i = 0; i < npollfds; i++) {
fd = pollfds[i].fd;
if (fd >= maxfd)
maxfd = fd + 1;
revents = pollfds[i].revents;
fd_event(ads, fd, revents, ADNS_POLLIN, maxfd, readfds, adns_processreadable, now, r_r);
fd_event(ads, fd, revents, ADNS_POLLOUT, maxfd, writefds, adns_processwriteable, now, r_r);
fd_event(ads, fd, revents, ADNS_POLLPRI, maxfd, exceptfds,
adns_processexceptional, now, r_r);
}
}
/* Wrappers for select(2). */
#if 0
void adns_beforeselect(adns_state ads, int *maxfd_io, fd_set * readfds_io,
fd_set * writefds_io, fd_set * exceptfds_io,
struct timeval **tv_mod, struct timeval *tv_tobuf, const struct timeval *now)
{
struct timeval tv_nowbuf;
struct adns_pollfd pollfds[MAX_POLLFDS];
int i, fd, maxfd, npollfds;
adns__consistency(ads, 0, cc_entex);
if (tv_mod && (!*tv_mod || (*tv_mod)->tv_sec || (*tv_mod)->tv_usec)) {
/* The caller is planning to sleep. */
adns__must_gettimeofday(ads, &now, &tv_nowbuf);
if (!now) {
inter_immed(tv_mod, tv_tobuf);
goto xit;
}
adns__timeouts(ads, 0, tv_mod, tv_tobuf, *now);
}
npollfds = adns__pollfds(ads, pollfds);
maxfd = *maxfd_io;
for (i = 0; i < npollfds; i++) {
fd = pollfds[i].fd;
if (fd >= maxfd)
maxfd = fd + 1;
if (pollfds[i].events & ADNS_POLLIN)
FD_SET(fd, readfds_io);
if (pollfds[i].events & ADNS_POLLOUT)
FD_SET(fd, writefds_io);
if (pollfds[i].events & ADNS_POLLPRI)
FD_SET(fd, exceptfds_io);
}
*maxfd_io = maxfd;
xit:
adns__consistency(ads, 0, cc_entex);
}
void adns_afterselect(adns_state ads, int maxfd, const fd_set * readfds,
const fd_set * writefds, const fd_set * exceptfds, const struct timeval *now)
{
struct timeval tv_buf;
struct adns_pollfd pollfds[MAX_POLLFDS];
int npollfds, i;
adns__consistency(ads, 0, cc_entex);
adns__must_gettimeofday(ads, &now, &tv_buf);
if (!now)
goto xit;
adns_processtimeouts(ads, now);
npollfds = adns__pollfds(ads, pollfds);
for (i = 0; i < npollfds; i++)
pollfds[i].revents = ADNS_POLLIN | ADNS_POLLOUT | ADNS_POLLPRI;
adns__fdevents(ads, pollfds, npollfds, maxfd, readfds, writefds, exceptfds, *now, 0);
xit:
adns__consistency(ads, 0, cc_entex);
}
#endif
/* General helpful functions. */
void adns_globalsystemfailure(adns_state ads)
{
adns__consistency(ads, 0, cc_entex);
while (ads->udpw.head)
adns__query_fail(ads->udpw.head, adns_s_systemfail);
while (ads->tcpw.head)
adns__query_fail(ads->tcpw.head, adns_s_systemfail);
switch (ads->tcpstate) {
case server_connecting:
case server_ok:
adns__tcp_broken(ads, 0, 0);
break;
case server_disconnected:
case server_broken:
break;
default:
abort();
}
adns__consistency(ads, 0, cc_entex);
}
int adns_processany(adns_state ads)
{
int r, i;
struct timeval now;
struct adns_pollfd pollfds[MAX_POLLFDS];
int npollfds;
adns__consistency(ads, 0, cc_entex);
r = gettimeofday(&now, 0);
if (!r)
adns_processtimeouts(ads, &now);
/* We just use adns__fdevents to loop over the fd's trying them.
* This seems more sensible than calling select, since we're most
* likely just to want to do a read on one or two fds anyway.
*/
npollfds = adns__pollfds(ads, pollfds);
for (i = 0; i < npollfds; i++)
pollfds[i].revents = pollfds[i].events & ~ADNS_POLLPRI;
adns__fdevents(ads, pollfds, npollfds, 0, 0, 0, 0, now, &r);
adns__consistency(ads, 0, cc_entex);
return 0;
}
void adns__autosys(adns_state ads, struct timeval now)
{
if (ads->iflags & adns_if_noautosys)
return;
adns_processany(ads);
}
int adns__internal_check(adns_state ads,
adns_query * query_io, adns_answer ** answer, void **context_r)
{
adns_query qu;
qu = *query_io;
if (!qu) {
if (ads->output.head) {
qu = ads->output.head;
} else if (ads->udpw.head || ads->tcpw.head) {
return EAGAIN;
} else {
return ESRCH;
}
} else {
if (qu->id >= 0)
return EAGAIN;
}
LIST_UNLINK(ads->output, qu);
*answer = qu->answer;
if (context_r)
*context_r = qu->ctx.ext;
*query_io = qu;
MyFree(qu);
return 0;
}
#if 0
int adns_wait(adns_state ads, adns_query * query_io, adns_answer ** answer_r, void **context_r)
{
int r, maxfd, rsel;
fd_set readfds, writefds, exceptfds;
struct timeval tvbuf, *tvp;
adns__consistency(ads, *query_io, cc_entex);
for (;;) {
r = adns__internal_check(ads, query_io, answer_r, context_r);
if (r != EAGAIN)
break;
maxfd = 0;
tvp = 0;
FD_ZERO(&readfds);
FD_ZERO(&writefds);
FD_ZERO(&exceptfds);
adns_beforeselect(ads, &maxfd, &readfds, &writefds, &exceptfds, &tvp, &tvbuf, 0);
assert(tvp);
rsel = select(maxfd, &readfds, &writefds, &exceptfds, tvp);
if (rsel == -1) {
if (errno == EINTR) {
if (ads->iflags & adns_if_eintr) {
r = EINTR;
break;
}
} else {
adns__diag(ads, -1, 0, "select failed in wait: %s", strerror(errno));
adns_globalsystemfailure(ads);
}
} else {
assert(rsel >= 0);
adns_afterselect(ads, maxfd, &readfds, &writefds, &exceptfds, 0);
}
}
adns__consistency(ads, 0, cc_entex);
return r;
}
#endif
int adns_check(adns_state ads, adns_query * query_io, adns_answer ** answer_r, void **context_r)
{
struct timeval now;
int r;
adns__consistency(ads, *query_io, cc_entex);
r = gettimeofday(&now, 0);
if (!r)
adns__autosys(ads, now);
r = adns__internal_check(ads, query_io, answer_r, context_r);
adns__consistency(ads, 0, cc_entex);
return r;
}
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