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OS/2 Shareware BBS: 35 Internet
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rsync221.zip
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socket.c
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1999-03-04
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/*
Copyright (C) Andrew Tridgell 1998
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 of the License, 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
socket functions used in rsync
*/
#include "rsync.h"
/* open a socket to a tcp remote host with the specified port
based on code from Warren */
int open_socket_out(char *host, int port)
{
int type = SOCK_STREAM;
struct sockaddr_in sock_out;
int res;
struct hostent *hp;
res = socket(PF_INET, type, 0);
if (res == -1) {
return -1;
}
hp = gethostbyname(host);
if (!hp) {
rprintf(FERROR,"unknown host: %s\n", host);
return -1;
}
memcpy(&sock_out.sin_addr, hp->h_addr, hp->h_length);
sock_out.sin_port = htons(port);
sock_out.sin_family = PF_INET;
if (connect(res,(struct sockaddr *)&sock_out,sizeof(sock_out))) {
close(res);
rprintf(FERROR,"failed to connect to %s - %s\n", host, strerror(errno));
return -1;
}
set_nonblocking(res);
return res;
}
/****************************************************************************
open a socket of the specified type, port and address for incoming data
****************************************************************************/
static int open_socket_in(int type, int port)
{
struct hostent *hp;
struct sockaddr_in sock;
char host_name[200];
int res;
int one=1;
/* get my host name */
if (gethostname(host_name, sizeof(host_name)) == -1) {
rprintf(FERROR,"gethostname failed\n");
return -1;
}
/* get host info */
if ((hp = gethostbyname(host_name)) == 0) {
rprintf(FERROR,"gethostbyname: Unknown host %s\n",host_name);
return -1;
}
memset((char *)&sock,0,sizeof(sock));
memcpy((char *)&sock.sin_addr,(char *)hp->h_addr, hp->h_length);
sock.sin_port = htons(port);
sock.sin_family = hp->h_addrtype;
sock.sin_addr.s_addr = INADDR_ANY;
res = socket(hp->h_addrtype, type, 0);
if (res == -1) {
rprintf(FERROR,"socket failed\n");
return -1;
}
setsockopt(res,SOL_SOCKET,SO_REUSEADDR,(char *)&one,sizeof(one));
/* now we've got a socket - we need to bind it */
if (bind(res, (struct sockaddr * ) &sock,sizeof(sock)) == -1) {
rprintf(FERROR,"bind failed on port %d\n", port);
close(res);
return -1;
}
return res;
}
/****************************************************************************
determine if a file descriptor is in fact a socket
****************************************************************************/
int is_a_socket(int fd)
{
int v,l;
l = sizeof(int);
return(getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&v, &l) == 0);
}
void start_accept_loop(int port, int (*fn)(int ))
{
int s;
/* open an incoming socket */
s = open_socket_in(SOCK_STREAM, port);
if (s == -1)
exit_cleanup(RERR_SOCKETIO);
/* ready to listen */
if (listen(s, 5) == -1) {
close(s);
exit_cleanup(RERR_SOCKETIO);
}
/* now accept incoming connections - forking a new process
for each incoming connection */
while (1) {
fd_set fds;
int fd;
struct sockaddr addr;
int in_addrlen = sizeof(addr);
FD_ZERO(&fds);
FD_SET(s, &fds);
if (select(s+1, &fds, NULL, NULL, NULL) != 1) {
continue;
}
if(!FD_ISSET(s, &fds)) continue;
fd = accept(s,&addr,&in_addrlen);
if (fd == -1) continue;
signal(SIGCHLD, SIG_IGN);
/* we shouldn't have any children left hanging around
but I have had reports that on Digital Unix zombies
are produced, so this ensures that they are reaped */
#ifdef WNOHANG
waitpid(-1, NULL, WNOHANG);
#endif
if (fork()==0) {
close(s);
set_nonblocking(fd);
_exit(fn(fd));
}
close(fd);
}
}
enum SOCK_OPT_TYPES {OPT_BOOL,OPT_INT,OPT_ON};
struct
{
char *name;
int level;
int option;
int value;
int opttype;
} socket_options[] = {
{"SO_KEEPALIVE", SOL_SOCKET, SO_KEEPALIVE, 0, OPT_BOOL},
{"SO_REUSEADDR", SOL_SOCKET, SO_REUSEADDR, 0, OPT_BOOL},
{"SO_BROADCAST", SOL_SOCKET, SO_BROADCAST, 0, OPT_BOOL},
#ifdef TCP_NODELAY
{"TCP_NODELAY", IPPROTO_TCP, TCP_NODELAY, 0, OPT_BOOL},
#endif
#ifdef IPTOS_LOWDELAY
{"IPTOS_LOWDELAY", IPPROTO_IP, IP_TOS, IPTOS_LOWDELAY, OPT_ON},
#endif
#ifdef IPTOS_THROUGHPUT
{"IPTOS_THROUGHPUT", IPPROTO_IP, IP_TOS, IPTOS_THROUGHPUT, OPT_ON},
#endif
#ifdef SO_SNDBUF
{"SO_SNDBUF", SOL_SOCKET, SO_SNDBUF, 0, OPT_INT},
#endif
#ifdef SO_RCVBUF
{"SO_RCVBUF", SOL_SOCKET, SO_RCVBUF, 0, OPT_INT},
#endif
#ifdef SO_SNDLOWAT
{"SO_SNDLOWAT", SOL_SOCKET, SO_SNDLOWAT, 0, OPT_INT},
#endif
#ifdef SO_RCVLOWAT
{"SO_RCVLOWAT", SOL_SOCKET, SO_RCVLOWAT, 0, OPT_INT},
#endif
#ifdef SO_SNDTIMEO
{"SO_SNDTIMEO", SOL_SOCKET, SO_SNDTIMEO, 0, OPT_INT},
#endif
#ifdef SO_RCVTIMEO
{"SO_RCVTIMEO", SOL_SOCKET, SO_RCVTIMEO, 0, OPT_INT},
#endif
{NULL,0,0,0,0}};
/****************************************************************************
set user socket options
****************************************************************************/
void set_socket_options(int fd, char *options)
{
char *tok;
if (!options || !*options) return;
options = strdup(options);
if (!options) out_of_memory("set_socket_options");
for (tok=strtok(options, " \t,"); tok; tok=strtok(NULL," \t,")) {
int ret=0,i;
int value = 1;
char *p;
int got_value = 0;
if ((p = strchr(tok,'='))) {
*p = 0;
value = atoi(p+1);
got_value = 1;
}
for (i=0;socket_options[i].name;i++)
if (strcmp(socket_options[i].name,tok)==0)
break;
if (!socket_options[i].name) {
rprintf(FERROR,"Unknown socket option %s\n",tok);
continue;
}
switch (socket_options[i].opttype) {
case OPT_BOOL:
case OPT_INT:
ret = setsockopt(fd,socket_options[i].level,
socket_options[i].option,(char *)&value,sizeof(int));
break;
case OPT_ON:
if (got_value)
rprintf(FERROR,"syntax error - %s does not take a value\n",tok);
{
int on = socket_options[i].value;
ret = setsockopt(fd,socket_options[i].level,
socket_options[i].option,(char *)&on,sizeof(int));
}
break;
}
if (ret != 0)
rprintf(FERROR,"Failed to set socket option %s\n",tok);
}
free(options);
}
/****************************************************************************
become a daemon, discarding the controlling terminal
****************************************************************************/
void become_daemon(void)
{
int i;
if (fork()) {
_exit(0);
}
/* detach from the terminal */
#ifdef HAVE_SETSID
setsid();
#else
#ifdef TIOCNOTTY
i = open("/dev/tty", O_RDWR);
if (i >= 0) {
ioctl(i, (int) TIOCNOTTY, (char *)0);
close(i);
}
#endif /* TIOCNOTTY */
#endif
/* make sure that stdin, stdout an stderr don't stuff things
up (library functions, for example) */
for (i=0;i<3;i++) {
close(i);
open("/dev/null", O_RDWR);
}
}
/*******************************************************************
return the IP addr of the client as a string
******************************************************************/
char *client_addr(int fd)
{
struct sockaddr sa;
struct sockaddr_in *sockin = (struct sockaddr_in *) (&sa);
int length = sizeof(sa);
static char addr_buf[100];
static int initialised;
if (initialised) return addr_buf;
initialised = 1;
if (getpeername(fd, &sa, &length)) {
exit_cleanup(RERR_SOCKETIO);
}
strlcpy(addr_buf,(char *)inet_ntoa(sockin->sin_addr), sizeof(addr_buf));
return addr_buf;
}
/*******************************************************************
return the DNS name of the client
******************************************************************/
char *client_name(int fd)
{
struct sockaddr sa;
struct sockaddr_in *sockin = (struct sockaddr_in *) (&sa);
int length = sizeof(sa);
static char name_buf[100];
struct hostent *hp;
char **p;
char *def = "UNKNOWN";
static int initialised;
if (initialised) return name_buf;
initialised = 1;
strcpy(name_buf,def);
if (getpeername(fd, &sa, &length)) {
exit_cleanup(RERR_SOCKETIO);
}
/* Look up the remote host name. */
if ((hp = gethostbyaddr((char *) &sockin->sin_addr,
sizeof(sockin->sin_addr),
AF_INET))) {
strlcpy(name_buf,(char *)hp->h_name,sizeof(name_buf));
}
/* do a forward lookup as well to prevent spoofing */
hp = gethostbyname(name_buf);
if (!hp) {
strcpy(name_buf,def);
rprintf(FERROR,"reverse name lookup failed\n");
} else {
for (p=hp->h_addr_list;*p;p++) {
if (memcmp(*p, &sockin->sin_addr, hp->h_length) == 0) {
break;
}
}
if (!*p) {
strcpy(name_buf,def);
rprintf(FERROR,"reverse name lookup mismatch - spoofed address?\n");
}
}
return name_buf;
}