-/**/
+/*
+ * event.c
+ * - event loop core
+ * - TCP connection management
+ * - user-visible check/wait and event-loop-related functions
+ */
+/*
+ * This file is part of adns, which is Copyright (C) 1997, 1998 Ian Jackson
+ *
+ * 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.
+ */
-#include "adns-internal.h"
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
-static void autosys(adns_state ads, struct timeval now) {
- if (ads->iflags & adns_if_noautosys) return;
- adns_callback(ads,-1,0,0,0);
+#include <netdb.h>
+#include <arpa/inet.h>
+
+#include "internal.h"
+
+/* TCP connection management */
+
+void adns__tcp_broken(adns_state ads, const char *what, const char *why) {
+ int serv;
+ adns_query qu, nqu;
+
+ assert(ads->tcpstate == server_connecting || ads->tcpstate == server_ok);
+ serv= ads->tcpserver;
+ adns__warn(ads,serv,0,"TCP connection lost: %s: %s",what,why);
+ close(ads->tcpsocket);
+ ads->tcpstate= server_disconnected;
+
+ for (qu= ads->timew.head; qu; qu= nqu) {
+ nqu= qu->next;
+ if (qu->state == query_udp) continue;
+ assert(qu->state == query_tcpwait || qu->state == query_tcpsent);
+ qu->state= query_tcpwait;
+ qu->tcpfailed |= (1<<serv);
+ if (qu->tcpfailed == (1<<ads->nservers)-1) {
+ LIST_UNLINK(ads->timew,qu);
+ adns__query_fail(qu,adns_s_allservfail);
+ }
+ }
+
+ ads->tcprecv.used= ads->tcpsend.used= 0;
+ 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->timew.head; qu; qu= nqu) {
+ nqu= qu->next;
+ if (qu->state == query_udp) continue;
+ assert (qu->state == query_tcpwait);
+ adns__query_tcp(qu,now);
+ }
+}
+
+void adns__tcp_tryconnect(adns_state ads, struct timeval now) {
+ int r, fd, tries;
+ struct sockaddr_in addr;
+ struct protoent *proto;
+ /* fixme: single TCP timeout, not once per server */
+
+ for (tries=0; tries<ads->nservers; tries++) {
+ if (ads->tcpstate == server_connecting || ads->tcpstate == server_ok) return;
+ assert(ads->tcpstate == server_disconnected);
+ assert(!ads->tcpsend.used);
+ assert(!ads->tcprecv.used);
+
+ proto= getprotobyname("tcp");
+ if (!proto) { adns__diag(ads,-1,0,"unable to find protocol no. for TCP !"); return; }
+ fd= socket(AF_INET,SOCK_STREAM,proto->p_proto);
+ 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));
+ 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,&addr,sizeof(addr));
+ ads->tcpsocket= fd;
+ ads->tcpstate= server_connecting;
+ if (r==0) { tcp_connected(ads,now); continue; }
+ if (errno == EWOULDBLOCK || errno == EINPROGRESS) return;
+ adns__tcp_broken(ads,"connect",strerror(errno));
+ }
+}
+
+/* `Interest' functions - find out which fd's we might be interested in,
+ * and when we want to be called back for a timeout.
+ */
+
+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) {
+ 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 inter_addfd(int *maxfd, fd_set *fds, int fd) {
+ if (!maxfd || !fds) return;
+ if (fd>=*maxfd) *maxfd= fd+1;
+ FD_SET(fd,fds);
}
+static void checktimeouts(adns_state ads, struct timeval now,
+ struct timeval **tv_io, struct timeval *tvbuf) {
+ adns_query qu, nqu;
+
+ for (qu= ads->timew.head; qu; qu= nqu) {
+ nqu= qu->next;
+ if (timercmp(&now,&qu->timeout,>)) {
+ LIST_UNLINK(ads->timew,qu);
+ if (qu->state != query_udp) {
+ adns__query_fail(qu,adns_s_timeout);
+ } else {
+ adns__query_udp(qu,now);
+ }
+ } else {
+ inter_maxtoabs(tv_io,tvbuf,now,qu->timeout);
+ }
+ }
+}
+
+void adns_interest(adns_state ads, int *maxfd,
+ fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
+ struct timeval **tv_io, struct timeval *tvbuf) {
+ struct timeval now;
+ struct timeval tvto_lr;
+ int r;
+
+/*fprintf(stderr,"adns_interest\n");*/
+
+ r= gettimeofday(&now,0);
+ if (r) {
+ adns__warn(ads,-1,0,"gettimeofday failed - will sleep for a bit: %s",
+ strerror(errno));
+ timerclear(&tvto_lr); timevaladd(&tvto_lr,LOCALRESOURCEMS);
+ inter_maxto(tv_io, tvbuf, tvto_lr);
+ } else {
+ checktimeouts(ads,now,tv_io,tvbuf);
+ }
+
+ inter_addfd(maxfd,readfds,ads->udpsocket);
+
+ switch (ads->tcpstate) {
+ case server_disconnected:
+ break;
+ case server_connecting:
+ inter_addfd(maxfd,writefds,ads->tcpsocket);
+ break;
+ case server_ok:
+ inter_addfd(maxfd,readfds,ads->tcpsocket);
+ inter_addfd(maxfd,exceptfds,ads->tcpsocket);
+ if (ads->tcpsend.used) inter_addfd(maxfd,writefds,ads->tcpsocket);
+ break;
+ default:
+ abort();
+ }
+}
+
+/* Callback procedures - these do the real work of reception and timeout, etc. */
+
static int callb_checkfd(int maxfd, const fd_set *fds, int fd) {
return maxfd<0 || !fds ? 1 :
fd<maxfd && FD_ISSET(fd,fds);
}
-static void tcpserver_broken(adns_state ads, const char *what, const char *why) {
- assert(ads->tcpstate == server_connecting || ads->tcpstate == server_connected);
- warn("nameserver %s TCP connection lost: %s: %s",
- inet_ntoa(ads->servers[tcpserver].addr,what,why));
- close(ads->tcpsocket);
- ads->tcpstate= server_disconnected;
-
-
-int adns_callback(adns_state ads, int maxfd,
- const fd_set *readfds, const fd_set *writefds,
- const fd_set *exceptfds) {
- int skip, dgramlen, count, udpaddrlen;
- enum adns__tcpstate oldtcpstate;
- unsigned char udpbuf[UDPMAXDGRAM];
+static int internal_callback(adns_state ads, int maxfd,
+ const fd_set *readfds, const fd_set *writefds,
+ const fd_set *exceptfds,
+ struct timeval now) {
+ int skip, want, dgramlen, count, udpaddrlen, r, serv;
+ byte udpbuf[DNS_MAXUDP];
struct sockaddr_in udpaddr;
count= 0;
- oldtcpstate= ads->tcpstate;
-
- if (ads->tcpstate == server_connecting) {
+
+ switch (ads->tcpstate) {
+ case server_disconnected:
+ break;
+ case server_connecting:
if (callb_checkfd(maxfd,writefds,ads->tcpsocket)) {
count++;
assert(ads->tcprecv.used==0);
- vbuf_ensure(&ads->tcprecv,1);
+ if (!adns__vbuf_ensure(&ads->tcprecv,1)) return -1;
if (ads->tcprecv.buf) {
r= read(ads->tcpsocket,&ads->tcprecv.buf,1);
if (r==0 || (r<0 && (errno==EAGAIN || errno==EWOULDBLOCK))) {
- debug("nameserver %s TCP connected",
- inet_ntoa(ads->servers[ads->tcpserver].addr));
- ads->tcpstate= server_connected;
+ tcp_connected(ads,now);
} else if (r>0) {
- tcpserver_broken(ads,"connect/read","sent data before first request");
+ adns__tcp_broken(ads,"connect/read","sent data before first request");
} else if (errno!=EINTR) {
- tcpserver_broken(ads,"connect",strerror(errno));
+ adns__tcp_broken(ads,"connect/read",strerror(errno));
}
}
}
- }
- if (ads->tcpstate == server_connected) {
- if (oldtcpstate == server_connected)
- count+= callb_checkfd(maxfd,readfds,ads->tcpsocket) +
- callb_checkfd(maxfd,exceptfds,ads->tcpsocket) +
- (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket));
- if (oldtcpstate != server_connected || callb_checkfd(maxfd,readfds,ads->tcpsocket)) {
+ break;
+ case server_ok:
+ count+= callb_checkfd(maxfd,readfds,ads->tcpsocket) +
+ callb_checkfd(maxfd,exceptfds,ads->tcpsocket) +
+ (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket));
+ if (callb_checkfd(maxfd,readfds,ads->tcpsocket)) {
skip= 0;
for (;;) {
if (ads->tcprecv.used<skip+2) {
if (ads->tcprecv.used<skip+2+dgramlen) {
want= 2+dgramlen;
} else {
- procdgram(ads,ads->tcprecv.buf+skip+2,dgramlen,ads->tcpserver);
+ adns__procdgram(ads,ads->tcprecv.buf+skip+2,dgramlen,ads->tcpserver,now);
skip+= 2+dgramlen; continue;
}
}
ads->tcprecv.used -= skip;
memmove(ads->tcprecv.buf,ads->tcprecv.buf+skip,ads->tcprecv.used);
- vbuf_ensure(&ads->tcprecv,want);
- if (ads->tcprecv.used >= ads->tcprecv.avail) break;
+ skip= 0;
+ if (!adns__vbuf_ensure(&ads->tcprecv,want)) return -1;
+ 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 (errno==EAGAIN || errno==EWOULDBLOCK || errno==ENOMEM) break;
if (errno==EINTR) continue;
}
- tcpserver_broken(ads->tcpserver,"read",r?strerror(errno):"closed");
+ adns__tcp_broken(ads,"read",r?strerror(errno):"closed");
break;
}
}
} else if (callb_checkfd(maxfd,exceptfds,ads->tcpsocket)) {
- tcpserver_broken(ads->tcpserver,"select","exceptional condition detected");
+ adns__tcp_broken(ads,"select","exceptional condition detected");
} else if (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket)) {
r= write(ads->tcpsocket,ads->tcpsend.buf,ads->tcpsend.used);
if (r<0) {
if (errno!=EAGAIN && errno!=EWOULDBLOCK && errno!=ENOMEM && errno!=EINTR) {
- tcpserver_broken(ads->tcpserver,"write",strerror(errno));
+ adns__tcp_broken(ads,"write",strerror(errno));
}
} else if (r>0) {
ads->tcpsend.used -= r;
memmove(ads->tcpsend.buf,ads->tcpsend.buf+r,ads->tcpsend.used);
}
}
+ break;
+ default:
+ abort();
}
if (callb_checkfd(maxfd,readfds,ads->udpsocket)) {
if (r<0) {
if (!(errno == EAGAIN || errno == EWOULDBLOCK ||
errno == EINTR || errno == ENOMEM || errno == ENOBUFS))
- warn("datagram receive error: %s",strerror(errno));
+ adns__warn(ads,-1,0,"datagram receive error: %s",strerror(errno));
break;
}
if (udpaddrlen != sizeof(udpaddr)) {
- diag("datagram received with wrong address length %d (expected %d)",
- udpaddrlen,sizeof(udpaddr));
+ adns__diag(ads,-1,0,"datagram received with wrong address length %d"
+ " (expected %d)", udpaddrlen,sizeof(udpaddr));
continue;
}
if (udpaddr.sin_family != AF_INET) {
- diag("datagram received with wrong protocol family %u (expected %u)",
- 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) != NSPORT) {
- diag("datagram received from wrong port %u (expected %u)",
- ntohs(udpaddr.sin_port),NSPORT);
+ 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;
ads->servers[serv].addr.s_addr != udpaddr.sin_addr.s_addr;
serv++);
if (serv >= ads->nservers) {
- warn("datagram received from unknown nameserver %s",inet_ntoa(udpaddr.sin_addr));
+ adns__warn(ads,-1,0,"datagram received from unknown nameserver %s",
+ inet_ntoa(udpaddr.sin_addr));
continue;
}
- procdgram(ads,udpbuf,r,serv);
+ adns__procdgram(ads,udpbuf,r,serv,now);
}
}
+ return count;
}
-static void inter_maxto(struct timeval **tv_io, struct timeval *tvbuf,
- struct timeval maxto) {
- struct timeval rbuf;
-
- rbuf= *tv_io;
- if (!rbuf) { *tvbuf= maxto; *tv_io= tvbuf; return; }
- if (timercmp(rbuf,&maxto,>)) *rbuf= maxto;
-}
-
-static void inter_maxtoabs(struct timeval **tv_io, struct timeval *tvbuf,
- struct timeval now, struct timeval maxtime) {
- ldiv_t dr;
-
- maxtime.tv_sec -= (now.tv_sec-1);
- maxtime.tv_usec += (1000-now.tv_usec);
- dr= ldiv(maxtime.tv_usec,1000);
- maxtime.tv_sec += dr.quot;
- maxtime.tv_usec -= dr.rem;
- inter_maxto(tv_io,tvbuf,maxtime);
-}
-
-static void localresourcerr(struct timeval **tv_io, struct timeval *tvbuf,
- const char *syscall) {
- struct timeval tvto_lr;
-
- warn(ads,"local system resources scarce (during %s): %s",syscall,strerror(errno));
- timerclear(&tvto_lr); timevaladd(&tvto_lr,LOCALRESOURCEMS);
- inter_maxto(tv_io, tvbuf, tvto_lr);
- return;
-}
-
-static void inter_addfd(int *maxfd, fd_set *fds, int fd) {
- if (fd>=*maxfd) *maxfd= fd+1;
- FD_SET(fd,fds);
-}
-
-void adns_interest(adns_state ads, int *maxfd,
- fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
- struct timeval **tv_io, struct timeval *tvbuf) {
+int adns_callback(adns_state ads, int maxfd,
+ const fd_set *readfds, const fd_set *writefds,
+ const fd_set *exceptfds) {
struct timeval now;
- adns_query qu;
int r;
-
- r= gettimeofday(&now,0);
- if (r) { localresourcerr(tv_io,tvbuf,"gettimeofday"); return; }
- for (qu= ads->timew; qu; qu= nqu) {
- nqu= qu->next;
- if (timercmp(&now,qu->timeout,>)) {
- DLIST_UNLINK(ads->timew,qu);
- if (qu->nextudpserver == -1) {
- query_fail(ads,qu,adns_s_notresponding);
- } else {
- DLIST_LINKTAIL(ads->tosend,qu);
- }
- } else {
- inter_maxtoabs(tv_io,tvbuf,now,qu->timeout);
- }
- }
-
- for (qu= ads->tosend; qu; qu= nqu) {
- nqu= qu->next;
- quproc_tosend(ads,qu,now);
- }
+ r= gettimeofday(&now,0); if (r) return -1;
+ checktimeouts(ads,now,0,0);
+ return internal_callback(ads,maxfd,readfds,writefds,exceptfds,now);
+}
- inter_addfd(maxfd,readfds,ads->udpsocket);
+/* User-visible functions and their implementation. */
- switch (ads->tcpstate) {
- case server_disc:
- break;
- case server_connecting:
- inter_addfd(maxfd,writefds,ads->tcpsocket);
- break;
- case server_connected:
- inter_addfd(maxfd,readfds,ads->tcpsocket);
- inter_addfd(maxfd,exceptfds,ads->tcpsocket);
- if (ads->opbufused) inter_addfd(maxfd,writefds,ads->tcpsocket);
- default:
- abort();
- }
+void adns__autosys(adns_state ads, struct timeval now) {
+ if (ads->iflags & adns_if_noautosys) return;
+ adns_callback(ads,-1,0,0,0);
}
static int internal_check(adns_state ads,
}
LIST_UNLINK(ads->output,qu);
*answer= qu->answer;
- if (context_r) *context_r= qu->context;
+ if (context_r) *context_r= qu->ctx.ext;
free(qu);
return 0;
}
for (;;) {
r= internal_check(ads,query_io,answer_r,context_r);
- if (r && r != EWOULDBLOCK) return r;
+ if (r != EWOULDBLOCK) return r;
maxfd= 0; tvp= 0;
FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds);
adns_interest(ads,&maxfd,&readfds,&writefds,&exceptfds,&tvp,&tvbuf);
rsel= select(maxfd,&readfds,&writefds,&exceptfds,tvp);
- if (rsel==-1) return r;
+ if (rsel==-1) {
+ if (errno == EINTR && !(ads->iflags & adns_if_eintr)) continue;
+ return errno;
+ }
rcb= adns_callback(ads,maxfd,&readfds,&writefds,&exceptfds);
assert(rcb==rsel);
}
adns_query *query_io,
adns_answer **answer_r,
void **context_r) {
- autosys(ads);
+ struct timeval now;
+ int r;
+
+ r= gettimeofday(&now,0); if (r) return errno;
+ adns__autosys(ads,now);
return internal_check(ads,query_io,answer_r,context_r);
}
~mdw / adns / blobdiff