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curl/tests/server/sockfilt.c
Marc Hoersken 4e2ed01a2e sockfilt.c: Fixed detection of client-side connection close 
WINSOCK only:
Since FD_CLOSE is only signaled once, it may trigger at the same
time as FD_READ. Data actually being available makes it impossible
to detect that the connection was closed by checking that recv returns
zero. Another recv attempt could block the connection if it was
not closed. This workaround abuses exceptfds in conjunction with
readfds to signal that the connection has actually closed.
2013-04-06 23:09:50 +02:00

1407 lines
38 KiB
C
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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at http://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
#include "server_setup.h"
/* Purpose
*
* 1. Accept a TCP connection on a custom port (ipv4 or ipv6), or connect
* to a given (localhost) port.
*
* 2. Get commands on STDIN. Pass data on to the TCP stream.
* Get data from TCP stream and pass on to STDOUT.
*
* This program is made to perform all the socket/stream/connection stuff for
* the test suite's (perl) FTP server. Previously the perl code did all of
* this by its own, but I decided to let this program do the socket layer
* because of several things:
*
* o We want the perl code to work with rather old perl installations, thus
* we cannot use recent perl modules or features.
*
* o We want IPv6 support for systems that provide it, and doing optional IPv6
* support in perl seems if not impossible so at least awkward.
*
* o We want FTP-SSL support, which means that a connection that starts with
* plain sockets needs to be able to "go SSL" in the midst. This would also
* require some nasty perl stuff I'd rather avoid.
*
* (Source originally based on sws.c)
*/
/*
* Signal handling notes for sockfilt
* ----------------------------------
*
* This program is a single-threaded process.
*
* This program is intended to be highly portable and as such it must be kept as
* simple as possible, due to this the only signal handling mechanisms used will
* be those of ANSI C, and used only in the most basic form which is good enough
* for the purpose of this program.
*
* For the above reason and the specific needs of this program signals SIGHUP,
* SIGPIPE and SIGALRM will be simply ignored on systems where this can be done.
* If possible, signals SIGINT and SIGTERM will be handled by this program as an
* indication to cleanup and finish execution as soon as possible. This will be
* achieved with a single signal handler 'exit_signal_handler' for both signals.
*
* The 'exit_signal_handler' upon the first SIGINT or SIGTERM received signal
* will just set to one the global var 'got_exit_signal' storing in global var
* 'exit_signal' the signal that triggered this change.
*
* Nothing fancy that could introduce problems is used, the program at certain
* points in its normal flow checks if var 'got_exit_signal' is set and in case
* this is true it just makes its way out of loops and functions in structured
* and well behaved manner to achieve proper program cleanup and termination.
*
* Even with the above mechanism implemented it is worthwile to note that other
* signals might still be received, or that there might be systems on which it
* is not possible to trap and ignore some of the above signals. This implies
* that for increased portability and reliability the program must be coded as
* if no signal was being ignored or handled at all. Enjoy it!
*/
#ifdef HAVE_SIGNAL_H
#include <signal.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef USE_WINSOCK
#include <conio.h> /* for _kbhit() used in select_ws() */
#endif
#define ENABLE_CURLX_PRINTF
/* make the curlx header define all printf() functions to use the curlx_*
versions instead */
#include "curlx.h" /* from the private lib dir */
#include "getpart.h"
#include "inet_pton.h"
#include "util.h"
#include "server_sockaddr.h"
#include "warnless.h"
/* include memdebug.h last */
#include "memdebug.h"
#ifdef USE_WINSOCK
#undef EINTR
#define EINTR 4 /* errno.h value */
#undef EAGAIN
#define EAGAIN 11 /* errno.h value */
#undef ENOMEM
#define ENOMEM 12 /* errno.h value */
#undef EINVAL
#define EINVAL 22 /* errno.h value */
#endif
#define DEFAULT_PORT 8999
#ifndef DEFAULT_LOGFILE
#define DEFAULT_LOGFILE "log/sockfilt.log"
#endif
const char *serverlogfile = DEFAULT_LOGFILE;
static bool verbose = FALSE;
static bool bind_only = FALSE;
#ifdef ENABLE_IPV6
static bool use_ipv6 = FALSE;
#endif
static const char *ipv_inuse = "IPv4";
static unsigned short port = DEFAULT_PORT;
static unsigned short connectport = 0; /* if non-zero, we activate this mode */
enum sockmode {
PASSIVE_LISTEN, /* as a server waiting for connections */
PASSIVE_CONNECT, /* as a server, connected to a client */
ACTIVE, /* as a client, connected to a server */
ACTIVE_DISCONNECT /* as a client, disconnected from server */
};
/* do-nothing macro replacement for systems which lack siginterrupt() */
#ifndef HAVE_SIGINTERRUPT
#define siginterrupt(x,y) do {} while(0)
#endif
/* vars used to keep around previous signal handlers */
typedef RETSIGTYPE (*SIGHANDLER_T)(int);
#ifdef SIGHUP
static SIGHANDLER_T old_sighup_handler = SIG_ERR;
#endif
#ifdef SIGPIPE
static SIGHANDLER_T old_sigpipe_handler = SIG_ERR;
#endif
#ifdef SIGALRM
static SIGHANDLER_T old_sigalrm_handler = SIG_ERR;
#endif
#ifdef SIGINT
static SIGHANDLER_T old_sigint_handler = SIG_ERR;
#endif
#ifdef SIGTERM
static SIGHANDLER_T old_sigterm_handler = SIG_ERR;
#endif
#if defined(SIGBREAK) && defined(WIN32)
static SIGHANDLER_T old_sigbreak_handler = SIG_ERR;
#endif
/* var which if set indicates that the program should finish execution */
SIG_ATOMIC_T got_exit_signal = 0;
/* if next is set indicates the first signal handled in exit_signal_handler */
static volatile int exit_signal = 0;
/* signal handler that will be triggered to indicate that the program
should finish its execution in a controlled manner as soon as possible.
The first time this is called it will set got_exit_signal to one and
store in exit_signal the signal that triggered its execution. */
static RETSIGTYPE exit_signal_handler(int signum)
{
int old_errno = errno;
if(got_exit_signal == 0) {
got_exit_signal = 1;
exit_signal = signum;
}
(void)signal(signum, exit_signal_handler);
errno = old_errno;
}
static void install_signal_handlers(void)
{
#ifdef SIGHUP
/* ignore SIGHUP signal */
if((old_sighup_handler = signal(SIGHUP, SIG_IGN)) == SIG_ERR)
logmsg("cannot install SIGHUP handler: %s", strerror(errno));
#endif
#ifdef SIGPIPE
/* ignore SIGPIPE signal */
if((old_sigpipe_handler = signal(SIGPIPE, SIG_IGN)) == SIG_ERR)
logmsg("cannot install SIGPIPE handler: %s", strerror(errno));
#endif
#ifdef SIGALRM
/* ignore SIGALRM signal */
if((old_sigalrm_handler = signal(SIGALRM, SIG_IGN)) == SIG_ERR)
logmsg("cannot install SIGALRM handler: %s", strerror(errno));
#endif
#ifdef SIGINT
/* handle SIGINT signal with our exit_signal_handler */
if((old_sigint_handler = signal(SIGINT, exit_signal_handler)) == SIG_ERR)
logmsg("cannot install SIGINT handler: %s", strerror(errno));
else
siginterrupt(SIGINT, 1);
#endif
#ifdef SIGTERM
/* handle SIGTERM signal with our exit_signal_handler */
if((old_sigterm_handler = signal(SIGTERM, exit_signal_handler)) == SIG_ERR)
logmsg("cannot install SIGTERM handler: %s", strerror(errno));
else
siginterrupt(SIGTERM, 1);
#endif
#if defined(SIGBREAK) && defined(WIN32)
/* handle SIGBREAK signal with our exit_signal_handler */
if((old_sigbreak_handler = signal(SIGBREAK, exit_signal_handler)) == SIG_ERR)
logmsg("cannot install SIGBREAK handler: %s", strerror(errno));
else
siginterrupt(SIGBREAK, 1);
#endif
}
static void restore_signal_handlers(void)
{
#ifdef SIGHUP
if(SIG_ERR != old_sighup_handler)
(void)signal(SIGHUP, old_sighup_handler);
#endif
#ifdef SIGPIPE
if(SIG_ERR != old_sigpipe_handler)
(void)signal(SIGPIPE, old_sigpipe_handler);
#endif
#ifdef SIGALRM
if(SIG_ERR != old_sigalrm_handler)
(void)signal(SIGALRM, old_sigalrm_handler);
#endif
#ifdef SIGINT
if(SIG_ERR != old_sigint_handler)
(void)signal(SIGINT, old_sigint_handler);
#endif
#ifdef SIGTERM
if(SIG_ERR != old_sigterm_handler)
(void)signal(SIGTERM, old_sigterm_handler);
#endif
#if defined(SIGBREAK) && defined(WIN32)
if(SIG_ERR != old_sigbreak_handler)
(void)signal(SIGBREAK, old_sigbreak_handler);
#endif
}
#ifdef WIN32
/*
* read-wrapper to support reading from stdin on Windows.
*/
static ssize_t read_wincon(int fd, void *buf, size_t count)
{
HANDLE handle = NULL;
DWORD mode, rcount = 0;
BOOL success;
if(fd == fileno(stdin)) {
handle = GetStdHandle(STD_INPUT_HANDLE);
}
else {
return read(fd, buf, count);
}
if(GetConsoleMode(handle, &mode)) {
success = ReadConsole(handle, buf, count, &rcount, NULL);
}
else {
success = ReadFile(handle, buf, count, &rcount, NULL);
}
if(success) {
return rcount;
}
errno = GetLastError();
return -1;
}
#define read(a,b,c) read_wincon(a,b,c)
/*
* write-wrapper to support writing to stdout and stderr on Windows.
*/
static ssize_t write_wincon(int fd, const void *buf, size_t count)
{
HANDLE handle = NULL;
DWORD mode, wcount = 0;
BOOL success;
if(fd == fileno(stdout)) {
handle = GetStdHandle(STD_OUTPUT_HANDLE);
}
else if(fd == fileno(stderr)) {
handle = GetStdHandle(STD_ERROR_HANDLE);
}
else {
return write(fd, buf, count);
}
if(GetConsoleMode(handle, &mode)) {
success = WriteConsole(handle, buf, count, &wcount, NULL);
}
else {
success = WriteFile(handle, buf, count, &wcount, NULL);
}
if(success) {
return wcount;
}
errno = GetLastError();
return -1;
}
#define write(a,b,c) write_wincon(a,b,c)
#endif
/*
* fullread is a wrapper around the read() function. This will repeat the call
* to read() until it actually has read the complete number of bytes indicated
* in nbytes or it fails with a condition that cannot be handled with a simple
* retry of the read call.
*/
static ssize_t fullread(int filedes, void *buffer, size_t nbytes)
{
int error;
ssize_t rc;
ssize_t nread = 0;
do {
rc = read(filedes, (unsigned char *)buffer + nread, nbytes - nread);
if(got_exit_signal) {
logmsg("signalled to die");
return -1;
}
if(rc < 0) {
error = errno;
if((error == EINTR) || (error == EAGAIN))
continue;
logmsg("reading from file descriptor: %d,", filedes);
logmsg("unrecoverable read() failure: (%d) %s",
error, strerror(error));
return -1;
}
if(rc == 0) {
logmsg("got 0 reading from stdin");
return 0;
}
nread += rc;
} while((size_t)nread < nbytes);
if(verbose)
logmsg("read %zd bytes", nread);
return nread;
}
/*
* fullwrite is a wrapper around the write() function. This will repeat the
* call to write() until it actually has written the complete number of bytes
* indicated in nbytes or it fails with a condition that cannot be handled
* with a simple retry of the write call.
*/
static ssize_t fullwrite(int filedes, const void *buffer, size_t nbytes)
{
int error;
ssize_t wc;
ssize_t nwrite = 0;
do {
wc = write(filedes, (unsigned char *)buffer + nwrite, nbytes - nwrite);
if(got_exit_signal) {
logmsg("signalled to die");
return -1;
}
if(wc < 0) {
error = errno;
if((error == EINTR) || (error == EAGAIN))
continue;
logmsg("writing to file descriptor: %d,", filedes);
logmsg("unrecoverable write() failure: (%d) %s",
error, strerror(error));
return -1;
}
if(wc == 0) {
logmsg("put 0 writing to stdout");
return 0;
}
nwrite += wc;
} while((size_t)nwrite < nbytes);
if(verbose)
logmsg("wrote %zd bytes", nwrite);
return nwrite;
}
/*
* read_stdin tries to read from stdin nbytes into the given buffer. This is a
* blocking function that will only return TRUE when nbytes have actually been
* read or FALSE when an unrecoverable error has been detected. Failure of this
* function is an indication that the sockfilt process should terminate.
*/
static bool read_stdin(void *buffer, size_t nbytes)
{
ssize_t nread = fullread(fileno(stdin), buffer, nbytes);
if(nread != (ssize_t)nbytes) {
logmsg("exiting...");
return FALSE;
}
return TRUE;
}
/*
* write_stdout tries to write to stdio nbytes from the given buffer. This is a
* blocking function that will only return TRUE when nbytes have actually been
* written or FALSE when an unrecoverable error has been detected. Failure of
* this function is an indication that the sockfilt process should terminate.
*/
static bool write_stdout(const void *buffer, size_t nbytes)
{
ssize_t nwrite = fullwrite(fileno(stdout), buffer, nbytes);
if(nwrite != (ssize_t)nbytes) {
logmsg("exiting...");
return FALSE;
}
return TRUE;
}
static void lograw(unsigned char *buffer, ssize_t len)
{
char data[120];
ssize_t i;
unsigned char *ptr = buffer;
char *optr = data;
ssize_t width=0;
for(i=0; i<len; i++) {
switch(ptr[i]) {
case '\n':
sprintf(optr, "\\n");
width += 2;
optr += 2;
break;
case '\r':
sprintf(optr, "\\r");
width += 2;
optr += 2;
break;
default:
sprintf(optr, "%c", (ISGRAPH(ptr[i]) || ptr[i]==0x20) ?ptr[i]:'.');
width++;
optr++;
break;
}
if(width>60) {
logmsg("'%s'", data);
width = 0;
optr = data;
}
}
if(width)
logmsg("'%s'", data);
}
#ifdef USE_WINSOCK
/*
* WinSock select() does not support standard file descriptors,
* it can only check SOCKETs. The following function is an attempt
* to re-create a select() function with support for other handle types.
*
* select() function with support for WINSOCK2 sockets and all
* other handle types supported by WaitForMultipleObjectsEx().
*
* TODO: Differentiate between read/write/except for non-SOCKET handles.
*
* http://msdn.microsoft.com/en-us/library/windows/desktop/ms687028.aspx
* http://msdn.microsoft.com/en-us/library/windows/desktop/ms741572.aspx
*/
static int select_ws(int nfds, fd_set *readfds, fd_set *writefds,
fd_set *exceptfds, struct timeval *timeout)
{
long networkevents;
DWORD milliseconds, wait, idx, mode, avail, events, inputs;
WSAEVENT wsaevent, *wsaevents;
WSANETWORKEVENTS wsanetevents;
INPUT_RECORD *inputrecords;
HANDLE handle, *handles;
curl_socket_t sock, *fdarr, *wsasocks;
int error, fds;
DWORD nfd = 0, wsa = 0;
int ret = 0;
/* check if the input value is valid */
if(nfds < 0) {
errno = EINVAL;
return -1;
}
/* check if we got descriptors, sleep in case we got none */
if(!nfds) {
Sleep((timeout->tv_sec * 1000) + (timeout->tv_usec / 1000));
return 0;
}
/* allocate internal array for the original input handles */
fdarr = malloc(nfds * sizeof(curl_socket_t));
if(fdarr == NULL) {
errno = ENOMEM;
return -1;
}
/* allocate internal array for the internal event handles */
handles = malloc(nfds * sizeof(HANDLE));
if(handles == NULL) {
errno = ENOMEM;
return -1;
}
/* allocate internal array for the internal socket handles */
wsasocks = malloc(nfds * sizeof(curl_socket_t));
if(wsasocks == NULL) {
errno = ENOMEM;
return -1;
}
/* allocate internal array for the internal WINSOCK2 events */
wsaevents = malloc(nfds * sizeof(WSAEVENT));
if(wsaevents == NULL) {
errno = ENOMEM;
return -1;
}
/* loop over the handles in the input descriptor sets */
for(fds = 0; fds < nfds; fds++) {
networkevents = 0;
handles[nfd] = 0;
if(FD_ISSET(fds, readfds))
networkevents |= FD_READ|FD_ACCEPT|FD_CLOSE;
if(FD_ISSET(fds, writefds))
networkevents |= FD_WRITE|FD_CONNECT;
if(FD_ISSET(fds, exceptfds))
networkevents |= FD_OOB|FD_CLOSE;
/* only wait for events for which we actually care */
if(networkevents) {
fdarr[nfd] = curlx_sitosk(fds);
if(fds == fileno(stdin)) {
handles[nfd] = GetStdHandle(STD_INPUT_HANDLE);
}
else if(fds == fileno(stdout)) {
handles[nfd] = GetStdHandle(STD_OUTPUT_HANDLE);
}
else if(fds == fileno(stderr)) {
handles[nfd] = GetStdHandle(STD_ERROR_HANDLE);
}
else {
wsaevent = WSACreateEvent();
if(wsaevent != WSA_INVALID_EVENT) {
error = WSAEventSelect(fds, wsaevent, networkevents);
if(error != SOCKET_ERROR) {
handles[nfd] = wsaevent;
wsasocks[wsa] = curlx_sitosk(fds);
wsaevents[wsa] = wsaevent;
wsa++;
}
else {
handles[nfd] = (HANDLE) curlx_sitosk(fds);
WSACloseEvent(wsaevent);
}
}
}
nfd++;
}
}
/* convert struct timeval to milliseconds */
if(timeout) {
milliseconds = ((timeout->tv_sec * 1000) + (timeout->tv_usec / 1000));
}
else {
milliseconds = INFINITE;
}
/* wait for one of the internal handles to trigger */
wait = WaitForMultipleObjectsEx(nfd, handles, FALSE, milliseconds, FALSE);
/* loop over the internal handles returned in the descriptors */
for(idx = 0; idx < nfd; idx++) {
handle = handles[idx];
sock = fdarr[idx];
fds = curlx_sktosi(sock);
/* check if the current internal handle was triggered */
if(wait != WAIT_FAILED && (wait - WAIT_OBJECT_0) <= idx &&
WaitForSingleObjectEx(handle, 0, FALSE) == WAIT_OBJECT_0) {
/* try to handle the event with STD* handle functions */
if(fds == fileno(stdin)) {
/* check if there is no data in the input buffer */
if(!stdin->_cnt) {
/* check if we are getting data from a PIPE */
if(!GetConsoleMode(handle, &mode)) {
/* check if there is no data from PIPE input */
if(!PeekNamedPipe(handle, NULL, 0, NULL, &avail, NULL))
avail = 0;
if(!avail) {
FD_CLR(sock, readfds);
/* reduce CPU load */
Sleep(10);
}
} /* check if there is no data from keyboard input */
else if (!_kbhit()) {
/* check if there are INPUT_RECORDs in the input buffer */
if(GetNumberOfConsoleInputEvents(handle, &events)) {
if(events > 0) {
/* remove INPUT_RECORDs from the input buffer */
inputrecords = (INPUT_RECORD*)malloc(events *
sizeof(INPUT_RECORD));
if(inputrecords) {
if(!ReadConsoleInput(handle, inputrecords,
events, &inputs))
inputs = 0;
free(inputrecords);
}
/* check if we got all inputs, otherwise clear buffer */
if(events != inputs)
FlushConsoleInputBuffer(handle);
}
}
/* remove from descriptor set since there is no real data */
FD_CLR(sock, readfds);
}
}
/* stdin is never ready for write or exceptional */
FD_CLR(sock, writefds);
FD_CLR(sock, exceptfds);
}
else if(fds == fileno(stdout) || fds == fileno(stderr)) {
/* stdout and stderr are never ready for read or exceptional */
FD_CLR(sock, readfds);
FD_CLR(sock, exceptfds);
}
else {
/* try to handle the event with the WINSOCK2 functions */
error = WSAEnumNetworkEvents(fds, handle, &wsanetevents);
if(error != SOCKET_ERROR) {
/* remove from descriptor set if not ready for read/accept/close */
if(!(wsanetevents.lNetworkEvents & (FD_READ|FD_ACCEPT|FD_CLOSE)))
FD_CLR(sock, readfds);
/* remove from descriptor set if not ready for write/connect */
if(!(wsanetevents.lNetworkEvents & (FD_WRITE|FD_CONNECT)))
FD_CLR(sock, writefds);
/* HACK:
* use exceptfds together with readfds to signal
* that the connection was closed by the client.
*
* Reason: FD_CLOSE is only signaled once, sometimes
* at the same time as FD_READ with data being available.
* This means that recv/sread is not reliable to detect
* that the connection is closed.
*/
/* remove from descriptor set if not exceptional */
if(!(wsanetevents.lNetworkEvents & (FD_OOB|FD_CLOSE)))
FD_CLR(sock, exceptfds);
}
}
/* check if the event has not been filtered using specific tests */
if(FD_ISSET(sock, readfds) || FD_ISSET(sock, writefds) ||
FD_ISSET(sock, exceptfds)) {
ret++;
}
}
else {
/* remove from all descriptor sets since this handle did not trigger */
FD_CLR(sock, readfds);
FD_CLR(sock, writefds);
FD_CLR(sock, exceptfds);
}
}
for(idx = 0; idx < wsa; idx++) {
WSAEventSelect(wsasocks[idx], NULL, 0);
WSACloseEvent(wsaevents[idx]);
}
free(wsaevents);
free(wsasocks);
free(handles);
free(fdarr);
return ret;
}
#define select(a,b,c,d,e) select_ws(a,b,c,d,e)
#endif /* USE_WINSOCK */
/*
sockfdp is a pointer to an established stream or CURL_SOCKET_BAD
if sockfd is CURL_SOCKET_BAD, listendfd is a listening socket we must
accept()
*/
static bool juggle(curl_socket_t *sockfdp,
curl_socket_t listenfd,
enum sockmode *mode)
{
struct timeval timeout;
fd_set fds_read;
fd_set fds_write;
fd_set fds_err;
curl_socket_t sockfd = CURL_SOCKET_BAD;
int maxfd = -99;
ssize_t rc;
ssize_t nread_socket;
ssize_t bytes_written;
ssize_t buffer_len;
int error = 0;
/* 'buffer' is this excessively large only to be able to support things like
test 1003 which tests exceedingly large server response lines */
unsigned char buffer[17010];
char data[16];
if(got_exit_signal) {
logmsg("signalled to die, exiting...");
return FALSE;
}
#ifdef HAVE_GETPPID
/* As a last resort, quit if sockfilt process becomes orphan. Just in case
parent ftpserver process has died without killing its sockfilt children */
if(getppid() <= 1) {
logmsg("process becomes orphan, exiting");
return FALSE;
}
#endif
timeout.tv_sec = 120;
timeout.tv_usec = 0;
FD_ZERO(&fds_read);
FD_ZERO(&fds_write);
FD_ZERO(&fds_err);
FD_SET((curl_socket_t)fileno(stdin), &fds_read);
switch(*mode) {
case PASSIVE_LISTEN:
/* server mode */
sockfd = listenfd;
/* there's always a socket to wait for */
FD_SET(sockfd, &fds_read);
maxfd = (int)sockfd;
break;
case PASSIVE_CONNECT:
sockfd = *sockfdp;
if(CURL_SOCKET_BAD == sockfd) {
/* eeek, we are supposedly connected and then this cannot be -1 ! */
logmsg("socket is -1! on %s:%d", __FILE__, __LINE__);
maxfd = 0; /* stdin */
}
else {
/* there's always a socket to wait for */
FD_SET(sockfd, &fds_read);
#ifdef USE_WINSOCK
FD_SET(sockfd, &fds_err);
#endif
maxfd = (int)sockfd;
}
break;
case ACTIVE:
sockfd = *sockfdp;
/* sockfd turns CURL_SOCKET_BAD when our connection has been closed */
if(CURL_SOCKET_BAD != sockfd) {
FD_SET(sockfd, &fds_read);
#ifdef USE_WINSOCK
FD_SET(sockfd, &fds_err);
#endif
maxfd = (int)sockfd;
}
else {
logmsg("No socket to read on");
maxfd = 0;
}
break;
case ACTIVE_DISCONNECT:
logmsg("disconnected, no socket to read on");
maxfd = 0;
sockfd = CURL_SOCKET_BAD;
break;
} /* switch(*mode) */
do {
/* select() blocking behavior call on blocking descriptors please */
rc = select(maxfd + 1, &fds_read, &fds_write, &fds_err, &timeout);
if(got_exit_signal) {
logmsg("signalled to die, exiting...");
return FALSE;
}
} while((rc == -1) && ((error = errno) == EINTR));
if(rc < 0) {
logmsg("select() failed with error: (%d) %s",
error, strerror(error));
return FALSE;
}
if(rc == 0)
/* timeout */
return TRUE;
if(FD_ISSET(fileno(stdin), &fds_read)) {
/* read from stdin, commands/data to be dealt with and possibly passed on
to the socket
protocol:
4 letter command + LF [mandatory]
4-digit hexadecimal data length + LF [if the command takes data]
data [the data being as long as set above]
Commands:
DATA - plain pass-thru data
*/
if(!read_stdin(buffer, 5))
return FALSE;
logmsg("Received %c%c%c%c (on stdin)",
buffer[0], buffer[1], buffer[2], buffer[3] );
if(!memcmp("PING", buffer, 4)) {
/* send reply on stdout, just proving we are alive */
if(!write_stdout("PONG\n", 5))
return FALSE;
}
else if(!memcmp("PORT", buffer, 4)) {
/* Question asking us what PORT number we are listening to.
Replies to PORT with "IPv[num]/[port]" */
sprintf((char *)buffer, "%s/%hu\n", ipv_inuse, port);
buffer_len = (ssize_t)strlen((char *)buffer);
snprintf(data, sizeof(data), "PORT\n%04zx\n", buffer_len);
if(!write_stdout(data, 10))
return FALSE;
if(!write_stdout(buffer, buffer_len))
return FALSE;
}
else if(!memcmp("QUIT", buffer, 4)) {
/* just die */
logmsg("quits");
return FALSE;
}
else if(!memcmp("DATA", buffer, 4)) {
/* data IN => data OUT */
if(!read_stdin(buffer, 5))
return FALSE;
buffer[5] = '\0';
buffer_len = (ssize_t)strtol((char *)buffer, NULL, 16);
if (buffer_len > (ssize_t)sizeof(buffer)) {
logmsg("ERROR: Buffer size (%zu bytes) too small for data size "
"(%zd bytes)", sizeof(buffer), buffer_len);
return FALSE;
}
logmsg("> %zd bytes data, server => client", buffer_len);
if(!read_stdin(buffer, buffer_len))
return FALSE;
lograw(buffer, buffer_len);
if(*mode == PASSIVE_LISTEN) {
logmsg("*** We are disconnected!");
if(!write_stdout("DISC\n", 5))
return FALSE;
}
else {
/* send away on the socket */
bytes_written = swrite(sockfd, buffer, buffer_len);
if(bytes_written != buffer_len) {
logmsg("Not all data was sent. Bytes to send: %zd sent: %zd",
buffer_len, bytes_written);
}
}
}
else if(!memcmp("DISC", buffer, 4)) {
/* disconnect! */
if(!write_stdout("DISC\n", 5))
return FALSE;
if(sockfd != CURL_SOCKET_BAD) {
logmsg("====> Client forcibly disconnected");
sclose(sockfd);
*sockfdp = CURL_SOCKET_BAD;
if(*mode == PASSIVE_CONNECT)
*mode = PASSIVE_LISTEN;
else
*mode = ACTIVE_DISCONNECT;
}
else
logmsg("attempt to close already dead connection");
return TRUE;
}
}
if((sockfd != CURL_SOCKET_BAD) && (FD_ISSET(sockfd, &fds_read)) ) {
curl_socket_t newfd = CURL_SOCKET_BAD; /* newly accepted socket */
if(*mode == PASSIVE_LISTEN) {
/* there's no stream set up yet, this is an indication that there's a
client connecting. */
newfd = accept(sockfd, NULL, NULL);
if(CURL_SOCKET_BAD == newfd) {
error = SOCKERRNO;
logmsg("accept(%d, NULL, NULL) failed with error: (%d) %s",
sockfd, error, strerror(error));
}
else {
logmsg("====> Client connect");
if(!write_stdout("CNCT\n", 5))
return FALSE;
*sockfdp = newfd; /* store the new socket */
*mode = PASSIVE_CONNECT; /* we have connected */
}
return TRUE;
}
/* read from socket, pass on data to stdout */
nread_socket = sread(sockfd, buffer, sizeof(buffer));
if(nread_socket > 0) {
snprintf(data, sizeof(data), "DATA\n%04zx\n", nread_socket);
if(!write_stdout(data, 10))
return FALSE;
if(!write_stdout(buffer, nread_socket))
return FALSE;
logmsg("< %zd bytes data, client => server", nread_socket);
lograw(buffer, nread_socket);
}
if(nread_socket <= 0
#ifdef USE_WINSOCK
|| FD_ISSET(sockfd, &fds_err)
#endif
) {
logmsg("====> Client disconnect");
if(!write_stdout("DISC\n", 5))
return FALSE;
sclose(sockfd);
*sockfdp = CURL_SOCKET_BAD;
if(*mode == PASSIVE_CONNECT)
*mode = PASSIVE_LISTEN;
else
*mode = ACTIVE_DISCONNECT;
return TRUE;
}
}
return TRUE;
}
static curl_socket_t sockdaemon(curl_socket_t sock,
unsigned short *listenport)
{
/* passive daemon style */
srvr_sockaddr_union_t listener;
int flag;
int rc;
int totdelay = 0;
int maxretr = 10;
int delay= 20;
int attempt = 0;
int error = 0;
do {
attempt++;
flag = 1;
rc = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
(void *)&flag, sizeof(flag));
if(rc) {
error = SOCKERRNO;
logmsg("setsockopt(SO_REUSEADDR) failed with error: (%d) %s",
error, strerror(error));
if(maxretr) {
rc = wait_ms(delay);
if(rc) {
/* should not happen */
error = errno;
logmsg("wait_ms() failed with error: (%d) %s",
error, strerror(error));
sclose(sock);
return CURL_SOCKET_BAD;
}
if(got_exit_signal) {
logmsg("signalled to die, exiting...");
sclose(sock);
return CURL_SOCKET_BAD;
}
totdelay += delay;
delay *= 2; /* double the sleep for next attempt */
}
}
} while(rc && maxretr--);
if(rc) {
logmsg("setsockopt(SO_REUSEADDR) failed %d times in %d ms. Error: (%d) %s",
attempt, totdelay, error, strerror(error));
logmsg("Continuing anyway...");
}
/* When the specified listener port is zero, it is actually a
request to let the system choose a non-zero available port. */
#ifdef ENABLE_IPV6
if(!use_ipv6) {
#endif
memset(&listener.sa4, 0, sizeof(listener.sa4));
listener.sa4.sin_family = AF_INET;
listener.sa4.sin_addr.s_addr = INADDR_ANY;
listener.sa4.sin_port = htons(*listenport);
rc = bind(sock, &listener.sa, sizeof(listener.sa4));
#ifdef ENABLE_IPV6
}
else {
memset(&listener.sa6, 0, sizeof(listener.sa6));
listener.sa6.sin6_family = AF_INET6;
listener.sa6.sin6_addr = in6addr_any;
listener.sa6.sin6_port = htons(*listenport);
rc = bind(sock, &listener.sa, sizeof(listener.sa6));
}
#endif /* ENABLE_IPV6 */
if(rc) {
error = SOCKERRNO;
logmsg("Error binding socket on port %hu: (%d) %s",
*listenport, error, strerror(error));
sclose(sock);
return CURL_SOCKET_BAD;
}
if(!*listenport) {
/* The system was supposed to choose a port number, figure out which
port we actually got and update the listener port value with it. */
curl_socklen_t la_size;
srvr_sockaddr_union_t localaddr;
#ifdef ENABLE_IPV6
if(!use_ipv6)
#endif
la_size = sizeof(localaddr.sa4);
#ifdef ENABLE_IPV6
else
la_size = sizeof(localaddr.sa6);
#endif
memset(&localaddr.sa, 0, (size_t)la_size);
if(getsockname(sock, &localaddr.sa, &la_size) < 0) {
error = SOCKERRNO;
logmsg("getsockname() failed with error: (%d) %s",
error, strerror(error));
sclose(sock);
return CURL_SOCKET_BAD;
}
switch (localaddr.sa.sa_family) {
case AF_INET:
*listenport = ntohs(localaddr.sa4.sin_port);
break;
#ifdef ENABLE_IPV6
case AF_INET6:
*listenport = ntohs(localaddr.sa6.sin6_port);
break;
#endif
default:
break;
}
if(!*listenport) {
/* Real failure, listener port shall not be zero beyond this point. */
logmsg("Apparently getsockname() succeeded, with listener port zero.");
logmsg("A valid reason for this failure is a binary built without");
logmsg("proper network library linkage. This might not be the only");
logmsg("reason, but double check it before anything else.");
sclose(sock);
return CURL_SOCKET_BAD;
}
}
/* bindonly option forces no listening */
if(bind_only) {
logmsg("instructed to bind port without listening");
return sock;
}
/* start accepting connections */
rc = listen(sock, 5);
if(0 != rc) {
error = SOCKERRNO;
logmsg("listen(%d, 5) failed with error: (%d) %s",
sock, error, strerror(error));
sclose(sock);
return CURL_SOCKET_BAD;
}
return sock;
}
int main(int argc, char *argv[])
{
srvr_sockaddr_union_t me;
curl_socket_t sock = CURL_SOCKET_BAD;
curl_socket_t msgsock = CURL_SOCKET_BAD;
int wrotepidfile = 0;
char *pidname= (char *)".sockfilt.pid";
bool juggle_again;
int rc;
int error;
int arg=1;
enum sockmode mode = PASSIVE_LISTEN; /* default */
const char *addr = NULL;
while(argc>arg) {
if(!strcmp("--version", argv[arg])) {
printf("sockfilt IPv4%s\n",
#ifdef ENABLE_IPV6
"/IPv6"
#else
""
#endif
);
return 0;
}
else if(!strcmp("--verbose", argv[arg])) {
verbose = TRUE;
arg++;
}
else if(!strcmp("--pidfile", argv[arg])) {
arg++;
if(argc>arg)
pidname = argv[arg++];
}
else if(!strcmp("--logfile", argv[arg])) {
arg++;
if(argc>arg)
serverlogfile = argv[arg++];
}
else if(!strcmp("--ipv6", argv[arg])) {
#ifdef ENABLE_IPV6
ipv_inuse = "IPv6";
use_ipv6 = TRUE;
#endif
arg++;
}
else if(!strcmp("--ipv4", argv[arg])) {
/* for completeness, we support this option as well */
#ifdef ENABLE_IPV6
ipv_inuse = "IPv4";
use_ipv6 = FALSE;
#endif
arg++;
}
else if(!strcmp("--bindonly", argv[arg])) {
bind_only = TRUE;
arg++;
}
else if(!strcmp("--port", argv[arg])) {
arg++;
if(argc>arg) {
char *endptr;
unsigned long ulnum = strtoul(argv[arg], &endptr, 10);
if((endptr != argv[arg] + strlen(argv[arg])) ||
((ulnum != 0UL) && ((ulnum < 1025UL) || (ulnum > 65535UL)))) {
fprintf(stderr, "sockfilt: invalid --port argument (%s)\n",
argv[arg]);
return 0;
}
port = curlx_ultous(ulnum);
arg++;
}
}
else if(!strcmp("--connect", argv[arg])) {
/* Asked to actively connect to the specified local port instead of
doing a passive server-style listening. */
arg++;
if(argc>arg) {
char *endptr;
unsigned long ulnum = strtoul(argv[arg], &endptr, 10);
if((endptr != argv[arg] + strlen(argv[arg])) ||
(ulnum < 1025UL) || (ulnum > 65535UL)) {
fprintf(stderr, "sockfilt: invalid --connect argument (%s)\n",
argv[arg]);
return 0;
}
connectport = curlx_ultous(ulnum);
arg++;
}
}
else if(!strcmp("--addr", argv[arg])) {
/* Set an IP address to use with --connect; otherwise use localhost */
arg++;
if(argc>arg) {
addr = argv[arg];
arg++;
}
}
else {
puts("Usage: sockfilt [option]\n"
" --version\n"
" --verbose\n"
" --logfile [file]\n"
" --pidfile [file]\n"
" --ipv4\n"
" --ipv6\n"
" --bindonly\n"
" --port [port]\n"
" --connect [port]\n"
" --addr [address]");
return 0;
}
}
#ifdef WIN32
win32_init();
atexit(win32_cleanup);
setmode(fileno(stdin), O_BINARY);
setmode(fileno(stdout), O_BINARY);
setmode(fileno(stderr), O_BINARY);
#endif
install_signal_handlers();
#ifdef ENABLE_IPV6
if(!use_ipv6)
#endif
sock = socket(AF_INET, SOCK_STREAM, 0);
#ifdef ENABLE_IPV6
else
sock = socket(AF_INET6, SOCK_STREAM, 0);
#endif
if(CURL_SOCKET_BAD == sock) {
error = SOCKERRNO;
logmsg("Error creating socket: (%d) %s",
error, strerror(error));
write_stdout("FAIL\n", 5);
goto sockfilt_cleanup;
}
if(connectport) {
/* Active mode, we should connect to the given port number */
mode = ACTIVE;
#ifdef ENABLE_IPV6
if(!use_ipv6) {
#endif
memset(&me.sa4, 0, sizeof(me.sa4));
me.sa4.sin_family = AF_INET;
me.sa4.sin_port = htons(connectport);
me.sa4.sin_addr.s_addr = INADDR_ANY;
if (!addr)
addr = "127.0.0.1";
Curl_inet_pton(AF_INET, addr, &me.sa4.sin_addr);
rc = connect(sock, &me.sa, sizeof(me.sa4));
#ifdef ENABLE_IPV6
}
else {
memset(&me.sa6, 0, sizeof(me.sa6));
me.sa6.sin6_family = AF_INET6;
me.sa6.sin6_port = htons(connectport);
if (!addr)
addr = "::1";
Curl_inet_pton(AF_INET6, addr, &me.sa6.sin6_addr);
rc = connect(sock, &me.sa, sizeof(me.sa6));
}
#endif /* ENABLE_IPV6 */
if(rc) {
error = SOCKERRNO;
logmsg("Error connecting to port %hu: (%d) %s",
connectport, error, strerror(error));
write_stdout("FAIL\n", 5);
goto sockfilt_cleanup;
}
logmsg("====> Client connect");
msgsock = sock; /* use this as stream */
}
else {
/* passive daemon style */
sock = sockdaemon(sock, &port);
if(CURL_SOCKET_BAD == sock) {
write_stdout("FAIL\n", 5);
goto sockfilt_cleanup;
}
msgsock = CURL_SOCKET_BAD; /* no stream socket yet */
}
logmsg("Running %s version", ipv_inuse);
if(connectport)
logmsg("Connected to port %hu", connectport);
else if(bind_only)
logmsg("Bound without listening on port %hu", port);
else
logmsg("Listening on port %hu", port);
wrotepidfile = write_pidfile(pidname);
if(!wrotepidfile) {
write_stdout("FAIL\n", 5);
goto sockfilt_cleanup;
}
do {
juggle_again = juggle(&msgsock, sock, &mode);
} while(juggle_again);
sockfilt_cleanup:
if((msgsock != sock) && (msgsock != CURL_SOCKET_BAD))
sclose(msgsock);
if(sock != CURL_SOCKET_BAD)
sclose(sock);
if(wrotepidfile)
unlink(pidname);
restore_signal_handlers();
if(got_exit_signal) {
logmsg("============> sockfilt exits with signal (%d)", exit_signal);
/*
* To properly set the return status of the process we
* must raise the same signal SIGINT or SIGTERM that we
* caught and let the old handler take care of it.
*/
raise(exit_signal);
}
logmsg("============> sockfilt quits");
return 0;
}
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