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socat/xio-listen.c

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/* source: xio-listen.c */
/* Copyright Gerhard Rieger */
/* Published under the GNU General Public License V.2, see file COPYING */
/* this file contains the source for listen socket options */
#include "xiosysincludes.h"
#if WITH_LISTEN
#include "xioopen.h"
#include "xio-named.h"
#include "xio-socket.h"
#include "xio-ip.h"
#include "xio-ip4.h"
#include "xio-listen.h"
#include "xio-tcpwrap.h"
/***** LISTEN options *****/
const struct optdesc opt_backlog = { "backlog", NULL, OPT_BACKLOG, GROUP_LISTEN, PH_LISTEN, TYPE_INT, OFUNC_SPEC };
const struct optdesc opt_fork = { "fork", NULL, OPT_FORK, GROUP_CHILD, PH_PASTACCEPT, TYPE_BOOL, OFUNC_SPEC };
const struct optdesc opt_max_children = { "max-children", NULL, OPT_MAX_CHILDREN, GROUP_CHILD, PH_PASTACCEPT, TYPE_INT, OFUNC_SPEC };
/**/
#if (WITH_UDP || WITH_TCP)
const struct optdesc opt_range = { "range", NULL, OPT_RANGE, GROUP_RANGE, PH_ACCEPT, TYPE_STRING, OFUNC_SPEC };
#endif
/*
applies and consumes the following option:
PH_INIT, PH_PASTSOCKET, PH_PREBIND, PH_BIND, PH_PASTBIND, PH_EARLY,
PH_PREOPEN, PH_FD, PH_CONNECTED, PH_LATE, PH_LATE2
OPT_FORK, OPT_SO_TYPE, OPT_SO_PROTOTYPE, OPT_BACKLOG, OPT_RANGE, tcpwrap,
OPT_SOURCEPORT, OPT_LOWPORT, cloexec
*/
int
xioopen_listen(struct single *xfd, int xioflags,
struct sockaddr *us, socklen_t uslen,
struct opt *opts, struct opt *opts0,
int pf, int socktype, int proto) {
int level;
int result;
#if WITH_RETRY
if (xfd->forever || xfd->retry) {
level = E_INFO;
} else
#endif /* WITH_RETRY */
level = E_ERROR;
while (true) { /* loop over failed attempts */
/* tcp listen; this can fork() for us; it only returns on error or on
successful establishment of tcp connection */
result = _xioopen_listen(xfd, xioflags,
(struct sockaddr *)us, uslen,
opts, pf, socktype, proto, level);
/*! not sure if we should try again on retry/forever */
switch (result) {
case STAT_OK: break;
#if WITH_RETRY
case STAT_RETRYLATER:
case STAT_RETRYNOW:
if (xfd->forever || xfd->retry) {
dropopts(opts, PH_ALL); opts = copyopts(opts0, GROUP_ALL);
if (result == STAT_RETRYLATER) {
Nanosleep(&xfd->intervall, NULL);
}
dropopts(opts, PH_ALL); opts = copyopts(opts0, GROUP_ALL);
--xfd->retry;
continue;
}
return STAT_NORETRY;
#endif /* WITH_RETRY */
default:
return result;
}
break;
} /* drop out on success */
return result;
}
/* creates the listening socket, bind, applies options; waits for incoming
connection, checks its source address and port. Depending on fork option, it
may fork a subprocess.
pf specifies the syntax expected for range option. In the case of generic
socket it is 0 (expecting raw binary data), and the real pf can be obtained
from us->af_family; for other socket types pf == us->af_family
Returns 0 if a connection was accepted; with fork option, this is always in
a subprocess!
Other return values indicate a problem; this can happen in the master
process or in a subprocess.
This function does not retry. If you need retries, handle this in a
loop in the calling function (and always provide the options...)
After fork, we set the forever/retry of the child process to 0
applies and consumes the following option:
PH_INIT, PH_PASTSOCKET, PH_PREBIND, PH_BIND, PH_PASTBIND, PH_EARLY,
PH_PREOPEN, PH_FD, PH_CONNECTED, PH_LATE, PH_LATE2
OPT_FORK, OPT_SO_TYPE, OPT_SO_PROTOTYPE, OPT_BACKLOG, OPT_RANGE, tcpwrap,
OPT_SOURCEPORT, OPT_LOWPORT, cloexec
*/
int _xioopen_listen(struct single *xfd, int xioflags, struct sockaddr *us, socklen_t uslen,
struct opt *opts, int pf, int socktype, int proto, int level) {
struct sockaddr sa;
socklen_t salen;
int backlog = 5; /* why? 1 seems to cause problems under some load */
char *rangename;
bool dofork = false;
int maxchildren = 0;
char infobuff[256];
char lisname[256];
union sockaddr_union _peername;
union sockaddr_union _sockname;
union sockaddr_union *pa = &_peername; /* peer address */
union sockaddr_union *la = &_sockname; /* local address */
socklen_t pas = sizeof(_peername); /* peer address size */
socklen_t las = sizeof(_sockname); /* local address size */
int result;
retropt_bool(opts, OPT_FORK, &dofork);
if (dofork) {
if (!(xioflags & XIO_MAYFORK)) {
Error("option fork not allowed here");
return STAT_NORETRY;
}
xfd->flags |= XIO_DOESFORK;
}
retropt_int(opts, OPT_MAX_CHILDREN, &maxchildren);
if (! dofork && maxchildren) {
Error("option max-children not allowed without option fork");
return STAT_NORETRY;
}
if (applyopts_single(xfd, opts, PH_INIT) < 0) return -1;
if (dofork) {
xiosetchilddied(); /* set SIGCHLD handler */
}
if ((xfd->fd = xiosocket(opts, us->sa_family, socktype, proto, level)) < 0) {
return STAT_RETRYLATER;
}
applyopts_cloexec(xfd->fd, opts);
applyopts(xfd->fd, opts, PH_PREBIND);
applyopts(xfd->fd, opts, PH_BIND);
if (Bind(xfd->fd, (struct sockaddr *)us, uslen) < 0) {
Msg4(level, "bind(%d, {%s}, "F_socklen"): %s", xfd->fd,
sockaddr_info(us, uslen, infobuff, sizeof(infobuff)), uslen,
strerror(errno));
Close(xfd->fd);
return STAT_RETRYLATER;
}
#if WITH_UNIX
if (us->sa_family == AF_UNIX) {
applyopts_named(((struct sockaddr_un *)us)->sun_path, opts, PH_FD);
}
#endif
/* under some circumstances (e.g., TCP listen on port 0) bind() fills empty
fields that we want to know. */
salen = sizeof(sa);
if (Getsockname(xfd->fd, us, &uslen) < 0) {
Warn4("getsockname(%d, %p, {%d}): %s",
xfd->fd, &us, uslen, strerror(errno));
}
applyopts(xfd->fd, opts, PH_PASTBIND);
#if WITH_UNIX
if (us->sa_family == AF_UNIX) {
/*applyopts_early(((struct sockaddr_un *)us)->sun_path, opts);*/
applyopts_named(((struct sockaddr_un *)us)->sun_path, opts, PH_EARLY);
applyopts_named(((struct sockaddr_un *)us)->sun_path, opts, PH_PREOPEN);
}
#endif /* WITH_UNIX */
#if WITH_IP4 /*|| WITH_IP6*/
if (retropt_string(opts, OPT_RANGE, &rangename) >= 0) {
if (xioparserange(rangename, pf, &xfd->para.socket.range)
< 0) {
free(rangename);
return STAT_NORETRY;
}
free(rangename);
xfd->para.socket.dorange = true;
}
#endif
#if (WITH_TCP || WITH_UDP) && WITH_LIBWRAP
xio_retropt_tcpwrap(xfd, opts);
#endif /* && (WITH_TCP || WITH_UDP) && WITH_LIBWRAP */
#if WITH_TCP || WITH_UDP
if (retropt_ushort(opts, OPT_SOURCEPORT, &xfd->para.socket.ip.sourceport) >= 0) {
xfd->para.socket.ip.dosourceport = true;
}
retropt_bool(opts, OPT_LOWPORT, &xfd->para.socket.ip.lowport);
#endif /* WITH_TCP || WITH_UDP */
applyopts(xfd->fd, opts, PH_PRELISTEN);
retropt_int(opts, OPT_BACKLOG, &backlog);
if (Listen(xfd->fd, backlog) < 0) {
Error3("listen(%d, %d): %s", xfd->fd, backlog, strerror(errno));
return STAT_RETRYLATER;
}
if (xioopts.logopt == 'm') {
Info("starting accept loop, switching to syslog");
diag_set('y', xioopts.syslogfac); xioopts.logopt = 'y';
} else {
Info("starting accept loop");
}
while (true) { /* but we only loop if fork option is set */
char peername[256];
char sockname[256];
int ps; /* peer socket */
pa = &_peername;
la = &_sockname;
salen = sizeof(struct sockaddr);
do {
/*? int level = E_ERROR;*/
Notice1("listening on %s", sockaddr_info(us, uslen, lisname, sizeof(lisname)));
ps = Accept(xfd->fd, (struct sockaddr *)&sa, &salen);
if (ps >= 0) {
/*0 Info4("accept(%d, %p, {"F_Zu"}) -> %d", xfd->fd, &sa, salen, ps);*/
break; /* success, break out of loop */
}
if (errno == EINTR) {
continue;
}
if (errno == ECONNABORTED) {
Notice4("accept(%d, %p, {"F_socklen"}): %s",
xfd->fd, &sa, salen, strerror(errno));
continue;
}
Msg4(level, "accept(%d, %p, {"F_socklen"}): %s",
xfd->fd, &sa, salen, strerror(errno));
Close(xfd->fd);
return STAT_RETRYLATER;
} while (true);
applyopts_cloexec(ps, opts);
if (Getpeername(ps, &pa->soa, &pas) < 0) {
Warn4("getpeername(%d, %p, {"F_socklen"}): %s",
ps, pa, pas, strerror(errno));
pa = NULL;
}
if (Getsockname(ps, &la->soa, &las) < 0) {
Warn4("getsockname(%d, %p, {"F_socklen"}): %s",
ps, la, las, strerror(errno));
la = NULL;
}
Notice2("accepting connection from %s on %s",
pa?
sockaddr_info(&pa->soa, pas, peername, sizeof(peername)):"NULL",
la?
sockaddr_info(&la->soa, las, sockname, sizeof(sockname)):"NULL");
if (pa != NULL && la != NULL && xiocheckpeer(xfd, pa, la) < 0) {
if (Shutdown(ps, 2) < 0) {
Info2("shutdown(%d, 2): %s", ps, strerror(errno));
}
Close(ps);
continue;
}
if (pa != NULL)
Info1("permitting connection from %s",
sockaddr_info((struct sockaddr *)pa, pas,
infobuff, sizeof(infobuff)));
if (dofork) {
pid_t pid; /* mostly int; only used with fork */
sigset_t mask_sigchld;
/* we must prevent that the current packet triggers another fork;
therefore we wait for a signal from the recent child: USR1
indicates that is has consumed the last packet; CHLD means it has
terminated */
/* block SIGCHLD and SIGUSR1 until parent is ready to react */
sigemptyset(&mask_sigchld);
sigaddset(&mask_sigchld, SIGCHLD);
Sigprocmask(SIG_BLOCK, &mask_sigchld, NULL);
if ((pid = xio_fork(false, level==E_ERROR?level:E_WARN)) < 0) {
Close(xfd->fd);
Sigprocmask(SIG_UNBLOCK, &mask_sigchld, NULL);
return STAT_RETRYLATER;
}
if (pid == 0) { /* child */
pid_t cpid = Getpid();
Sigprocmask(SIG_UNBLOCK, &mask_sigchld, NULL);
Info1("just born: child process "F_pid, cpid);
xiosetenvulong("PID", cpid, 1);
if (Close(xfd->fd) < 0) {
Info2("close(%d): %s", xfd->fd, strerror(errno));
}
xfd->fd = ps;
#if WITH_RETRY
/* !? */
xfd->forever = false; xfd->retry = 0;
level = E_ERROR;
#endif /* WITH_RETRY */
break;
}
/* server: continue loop with listen */
/* shutdown() closes the socket even for the child process, but
close() does what we want */
if (Close(ps) < 0) {
Info2("close(%d): %s", ps, strerror(errno));
}
/* now we are ready to handle signals */
Sigprocmask(SIG_UNBLOCK, &mask_sigchld, NULL);
while (maxchildren) {
if (num_child < maxchildren) break;
Notice("maxchildren are active, waiting");
/* UINT_MAX would even be nicer, but Openindiana works only
with 31 bits */
while (!Sleep(INT_MAX)) ; /* any signal lets us continue */
}
Info("still listening");
} else {
if (Close(xfd->fd) < 0) {
Info2("close(%d): %s", xfd->fd, strerror(errno));
}
xfd->fd = ps;
break;
}
}
applyopts(xfd->fd, opts, PH_FD);
applyopts(xfd->fd, opts, PH_PASTSOCKET);
applyopts(xfd->fd, opts, PH_CONNECTED);
if ((result = _xio_openlate(xfd, opts)) < 0)
return result;
/* set the env vars describing the local and remote sockets */
if (la != NULL) xiosetsockaddrenv("SOCK", la, las, proto);
if (pa != NULL) xiosetsockaddrenv("PEER", pa, pas, proto);
return 0;
}
#endif /* WITH_LISTEN */
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