branch: master
sockfilt.c
41295 bytesRaw
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 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 https://curl.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.
*
* SPDX-License-Identifier: curl
*
***************************************************************************/
#include "first.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 would 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 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 worthwhile 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!
*/
/* buffer is this excessively large only to be able to support things like
test 1003 which tests exceedingly large server response lines */
#define BUFFER_SIZE 17010
static bool verbose = FALSE;
static bool s_bind_only = FALSE;
static unsigned short server_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 */
};
#if defined(_WIN32) && !defined(CURL_WINDOWS_UWP)
/*
* 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, curlx_uztoul(count), &rcount, NULL);
}
else {
success = ReadFile(handle, buf, curlx_uztoul(count), &rcount, NULL);
}
if(success) {
return rcount;
}
errno = (int)GetLastError();
return -1;
}
/*
* 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, curlx_uztoul(count), &wcount, NULL);
}
else {
success = WriteFile(handle, buf, curlx_uztoul(count), &wcount, NULL);
}
if(success) {
return wcount;
}
errno = (int)GetLastError();
return -1;
}
#define SOCKFILT_read read_wincon
#define SOCKFILT_write write_wincon
#else
#define SOCKFILT_read read
#define SOCKFILT_write write
#endif
/* On Windows, we sometimes get this for a broken pipe, seemingly
* when the client just closed stdin? */
#define CURL_WIN32_EPIPE 109
/*
* 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 nread = 0;
do {
ssize_t rc = SOCKFILT_read(filedes,
(unsigned char *)buffer + nread,
nbytes - nread);
if(got_exit_signal) {
logmsg("signalled to die");
return -1;
}
if(rc < 0) {
char errbuf[STRERROR_LEN];
error = errno;
/* !checksrc! disable ERRNOVAR 1 */
if((error == EINTR) || (error == EAGAIN))
continue;
if(error == CURL_WIN32_EPIPE) {
logmsg("got Windows ERROR_BROKEN_PIPE on fd=%d, treating as close",
filedes);
return 0;
}
logmsg("reading from file descriptor: %d,", filedes);
logmsg("unrecoverable read() failure (%d) %s",
error, curlx_strerror(error, errbuf, sizeof(errbuf)));
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 nwrite = 0;
do {
ssize_t wc = SOCKFILT_write(filedes,
(const unsigned char *)buffer + nwrite,
nbytes - nwrite);
if(got_exit_signal) {
logmsg("signalled to die");
return -1;
}
if(wc < 0) {
char errbuf[STRERROR_LEN];
error = errno;
/* !checksrc! disable ERRNOVAR 1 */
if((error == EINTR) || (error == EAGAIN))
continue;
logmsg("writing to file descriptor: %d,", filedes);
logmsg("unrecoverable write() failure (%d) %s",
error, curlx_strerror(error, errbuf, sizeof(errbuf)));
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;
nwrite = fullwrite(fileno(stdout), buffer, nbytes);
if(nwrite != (ssize_t)nbytes) {
logmsg("exiting...");
return FALSE;
}
return TRUE;
}
static void lograw(const unsigned char *buffer, ssize_t len)
{
char data[120];
ssize_t i;
const unsigned char *ptr = buffer;
char *optr = data;
ssize_t width = 0;
int left = sizeof(data);
for(i = 0; i < len; i++) {
switch(ptr[i]) {
case '\n':
snprintf(optr, left, "\\n");
width += 2;
optr += 2;
left -= 2;
break;
case '\r':
snprintf(optr, left, "\\r");
width += 2;
optr += 2;
left -= 2;
break;
default:
snprintf(optr, left, "%c", (ISGRAPH(ptr[i]) ||
ptr[i] == 0x20) ? ptr[i] : '.');
width++;
optr++;
left--;
break;
}
if(width > 60) {
logmsg("'%s'", data);
width = 0;
optr = data;
left = sizeof(data);
}
}
if(width)
logmsg("'%s'", data);
}
/*
* handle the DATA command
* maxlen is the available space in buffer (input)
* *buffer_len is the amount of data in the buffer (output)
*/
static bool read_data_block(unsigned char *buffer, ssize_t maxlen,
ssize_t *buffer_len)
{
curl_off_t value;
const char *endp;
if(!read_stdin(buffer, 5))
return FALSE;
buffer[5] = '\0';
endp = (const char *)buffer;
if(curlx_str_hex(&endp, &value, 0xfffff)) {
logmsg("Failed to decode buffer size");
return FALSE;
}
*buffer_len = (ssize_t)value;
if(*buffer_len > maxlen) {
logmsg("Buffer size (%zd bytes) too small for data size error "
"(%zd bytes)", maxlen, *buffer_len);
return FALSE;
}
logmsg("> %zd bytes data, server => client", *buffer_len);
if(!read_stdin(buffer, *buffer_len))
return FALSE;
lograw(buffer, *buffer_len);
return TRUE;
}
#if defined(USE_WINSOCK) && !defined(CURL_WINDOWS_UWP)
/*
* 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() as
* well as disk files, anonymous and names pipes, and character input.
*
* https://learn.microsoft.com/windows/win32/api/synchapi/nf-synchapi-waitformultipleobjectsex
* https://learn.microsoft.com/windows/win32/api/winsock2/nf-winsock2-wsaenumnetworkevents
*/
struct select_ws_wait_data {
HANDLE handle; /* actual handle to wait for during select */
HANDLE signal; /* internal event to signal handle trigger */
HANDLE abort; /* internal event to abort waiting threads */
};
static DWORD WINAPI select_ws_wait_thread(void *lpParameter)
{
struct select_ws_wait_data *data;
HANDLE signal, handle, handles[2];
INPUT_RECORD inputrecord;
LARGE_INTEGER size, pos;
DWORD type, length, ret;
/* retrieve handles from internal structure */
data = (struct select_ws_wait_data *)lpParameter;
if(data) {
handle = data->handle;
handles[0] = data->abort;
handles[1] = handle;
signal = data->signal;
free(data);
}
else
return (DWORD)-1;
/* retrieve the type of file to wait on */
type = GetFileType(handle);
switch(type) {
case FILE_TYPE_DISK:
/* The handle represents a file on disk, this means:
* - WaitForMultipleObjectsEx will always be signalled for it.
* - comparison of current position in file and total size of
* the file can be used to check if we reached the end yet.
*
* Approach: Loop till either the internal event is signalled
* or if the end of the file has already been reached.
*/
while(WaitForMultipleObjectsEx(1, handles, FALSE, 0, FALSE)
== WAIT_TIMEOUT) {
/* get total size of file */
length = 0;
size.QuadPart = 0;
size.LowPart = GetFileSize(handle, &length);
if((size.LowPart != INVALID_FILE_SIZE) ||
(GetLastError() == NO_ERROR)) {
size.HighPart = (LONG)length;
/* get the current position within the file */
pos.QuadPart = 0;
pos.LowPart = SetFilePointer(handle, 0, &pos.HighPart, FILE_CURRENT);
if((pos.LowPart != INVALID_SET_FILE_POINTER) ||
(GetLastError() == NO_ERROR)) {
/* compare position with size, abort if not equal */
if(size.QuadPart == pos.QuadPart) {
/* sleep and continue waiting */
SleepEx(0, FALSE);
continue;
}
}
}
/* there is some data available, stop waiting */
logmsg("[select_ws_wait_thread] data available, DISK: %p", handle);
SetEvent(signal);
}
break;
case FILE_TYPE_CHAR:
/* The handle represents a character input, this means:
* - WaitForMultipleObjectsEx will be signalled on any kind of input,
* including mouse and window size events we do not care about.
*
* Approach: Loop till either the internal event is signalled
* or we get signalled for an actual key-event.
*/
while(WaitForMultipleObjectsEx(2, handles, FALSE, INFINITE, FALSE)
== WAIT_OBJECT_0 + 1) {
/* check if this is an actual console handle */
if(GetConsoleMode(handle, &ret)) {
/* retrieve an event from the console buffer */
length = 0;
if(PeekConsoleInput(handle, &inputrecord, 1, &length)) {
/* check if the event is not an actual key-event */
if(length == 1 && inputrecord.EventType != KEY_EVENT) {
/* purge the non-key-event and continue waiting */
ReadConsoleInput(handle, &inputrecord, 1, &length);
continue;
}
}
}
/* there is some data available, stop waiting */
logmsg("[select_ws_wait_thread] data available, CHAR: %p", handle);
SetEvent(signal);
}
break;
case FILE_TYPE_PIPE:
/* The handle represents an anonymous or named pipe, this means:
* - WaitForMultipleObjectsEx will always be signalled for it.
* - peek into the pipe and retrieve the amount of data available.
*
* Approach: Loop till either the internal event is signalled
* or there is data in the pipe available for reading.
*/
while(WaitForMultipleObjectsEx(1, handles, FALSE, 0, FALSE)
== WAIT_TIMEOUT) {
/* peek into the pipe and retrieve the amount of data available */
length = 0;
if(PeekNamedPipe(handle, NULL, 0, NULL, &length, NULL)) {
/* if there is no data available, sleep and continue waiting */
if(length == 0) {
SleepEx(0, FALSE);
continue;
}
else {
logmsg("[select_ws_wait_thread] PeekNamedPipe len: %lu", length);
}
}
else {
/* if the pipe has NOT been closed, sleep and continue waiting */
ret = GetLastError();
if(ret != ERROR_BROKEN_PIPE) {
char buffer[WINAPI_ERROR_LEN];
curlx_winapi_strerror(ret, buffer, sizeof(buffer));
logmsg("[select_ws_wait_thread] PeekNamedPipe error: (0x%08lx) - %s",
ret, buffer);
if(ret == ERROR_NOT_SUPPORTED) /* avoid potential endless loop */
break;
SleepEx(0, FALSE);
continue;
}
else {
logmsg("[select_ws_wait_thread] pipe closed, PIPE: %p", handle);
}
}
/* there is some data available, stop waiting */
logmsg("[select_ws_wait_thread] data available, PIPE: %p", handle);
SetEvent(signal);
}
break;
default:
/* The handle has an unknown type, try to wait on it */
if(WaitForMultipleObjectsEx(2, handles, FALSE, INFINITE, FALSE)
== WAIT_OBJECT_0 + 1) {
logmsg("[select_ws_wait_thread] data available, HANDLE: %p", handle);
SetEvent(signal);
}
break;
}
return 0;
}
static HANDLE select_ws_wait(HANDLE handle, HANDLE signal, HANDLE abort)
{
struct select_ws_wait_data *data;
/* allocate internal waiting data structure */
data = malloc(sizeof(struct select_ws_wait_data));
if(data) {
HANDLE thread;
data->handle = handle;
data->signal = signal;
data->abort = abort;
/* launch waiting thread */
thread = CreateThread(NULL, 0, &select_ws_wait_thread, data, 0, NULL);
/* free data if thread failed to launch */
if(!thread) {
free(data);
}
return thread;
}
return NULL;
}
struct select_ws_data {
int fd; /* provided file descriptor (indexed by nfd) */
long wsastate; /* internal preselect state (indexed by nfd) */
curl_socket_t wsasock; /* internal socket handle (indexed by nws) */
WSAEVENT wsaevent; /* internal select event (indexed by nws) */
HANDLE signal; /* internal thread signal (indexed by nth) */
HANDLE thread; /* internal thread handle (indexed by nth) */
};
static int select_ws(int nfds, fd_set *readfds, fd_set *writefds,
fd_set *exceptfds, struct timeval *tv)
{
DWORD timeout_ms, wait, nfd, nth, nws, i;
HANDLE abort, signal, handle, *handles;
struct select_ws_data *data;
WSANETWORKEVENTS wsaevents;
curl_socket_t wsasock;
int ret, fd;
/* check if the input value is valid */
if(nfds < 0) {
SET_SOCKERRNO(SOCKEINVAL);
return -1;
}
/* convert struct timeval to milliseconds */
if(tv) {
timeout_ms = (DWORD)curlx_tvtoms(tv);
}
else {
timeout_ms = INFINITE;
}
/* check if we got descriptors, sleep in case we got none */
if(!nfds) {
SleepEx(timeout_ms, FALSE);
return 0;
}
/* create internal event to abort waiting threads */
abort = CreateEvent(NULL, TRUE, FALSE, NULL);
if(!abort) {
SET_SOCKERRNO(SOCKENOMEM);
return -1;
}
/* allocate internal array for the internal data */
data = calloc(nfds, sizeof(struct select_ws_data));
if(!data) {
CloseHandle(abort);
SET_SOCKERRNO(SOCKENOMEM);
return -1;
}
/* allocate internal array for the internal event handles */
handles = calloc(nfds + 1, sizeof(HANDLE));
if(!handles) {
CloseHandle(abort);
free(data);
SET_SOCKERRNO(SOCKENOMEM);
return -1;
}
/* loop over the handles in the input descriptor sets */
nfd = 0; /* number of handled file descriptors */
nth = 0; /* number of internal waiting threads */
nws = 0; /* number of handled Winsock sockets */
for(fd = 0; fd < nfds; fd++) {
fd_set readsock, writesock, exceptsock;
wsasock = (curl_socket_t)fd;
wsaevents.lNetworkEvents = 0;
handles[nfd] = 0;
FD_ZERO(&readsock);
FD_ZERO(&writesock);
FD_ZERO(&exceptsock);
if(FD_ISSET(wsasock, readfds)) {
FD_SET(wsasock, &readsock);
wsaevents.lNetworkEvents |= FD_READ | FD_ACCEPT | FD_CLOSE;
}
if(FD_ISSET(wsasock, writefds)) {
FD_SET(wsasock, &writesock);
wsaevents.lNetworkEvents |= FD_WRITE | FD_CONNECT | FD_CLOSE;
}
if(FD_ISSET(wsasock, exceptfds)) {
FD_SET(wsasock, &exceptsock);
wsaevents.lNetworkEvents |= FD_OOB;
}
/* only wait for events for which we actually care */
if(wsaevents.lNetworkEvents) {
data[nfd].fd = fd;
if(fd == fileno(stdin)) {
signal = CreateEvent(NULL, TRUE, FALSE, NULL);
if(signal) {
handle = GetStdHandle(STD_INPUT_HANDLE);
handle = select_ws_wait(handle, signal, abort);
if(handle) {
handles[nfd] = signal;
data[nth].signal = signal;
data[nth].thread = handle;
nfd++;
nth++;
}
else {
CloseHandle(signal);
}
}
}
else if(fd == fileno(stdout)) {
handles[nfd] = GetStdHandle(STD_OUTPUT_HANDLE);
nfd++;
}
else if(fd == fileno(stderr)) {
handles[nfd] = GetStdHandle(STD_ERROR_HANDLE);
nfd++;
}
else {
WSAEVENT wsaevent;
wsaevent = WSACreateEvent();
if(wsaevent != WSA_INVALID_EVENT) {
if(wsaevents.lNetworkEvents & FD_WRITE) {
swrite(wsasock, NULL, 0); /* reset FD_WRITE */
}
if(WSAEventSelect(wsasock, wsaevent, wsaevents.lNetworkEvents)
== 0) {
handles[nfd] = (HANDLE)wsaevent;
data[nws].wsasock = wsasock;
data[nws].wsaevent = wsaevent;
data[nfd].wsastate = 0;
if(tv) {
tv->tv_sec = 0;
tv->tv_usec = 0;
}
/* check if the socket is already ready */
if(select(fd + 1, &readsock, &writesock, &exceptsock, tv) == 1) {
logmsg("[select_ws] socket %d is ready", fd);
WSASetEvent(wsaevent);
if(FD_ISSET(wsasock, &readsock))
data[nfd].wsastate |= FD_READ;
if(FD_ISSET(wsasock, &writesock))
data[nfd].wsastate |= FD_WRITE;
if(FD_ISSET(wsasock, &exceptsock))
data[nfd].wsastate |= FD_OOB;
}
nfd++;
nws++;
}
else {
WSACloseEvent(wsaevent);
signal = CreateEvent(NULL, TRUE, FALSE, NULL);
if(signal) {
handle = (HANDLE)wsasock;
handle = select_ws_wait(handle, signal, abort);
if(handle) {
handles[nfd] = signal;
data[nth].signal = signal;
data[nth].thread = handle;
nfd++;
nth++;
}
else {
CloseHandle(signal);
}
}
}
}
}
}
}
/* wait on the number of handles */
wait = nfd;
/* make sure we stop waiting on exit signal event */
if(exit_event) {
/* we allocated handles nfds + 1 for this */
handles[nfd] = exit_event;
wait += 1;
}
/* wait for one of the internal handles to trigger */
wait = WaitForMultipleObjectsEx(wait, handles, FALSE, timeout_ms, FALSE);
/* signal the abort event handle and join the other waiting threads */
SetEvent(abort);
for(i = 0; i < nth; i++) {
WaitForSingleObjectEx(data[i].thread, INFINITE, FALSE);
CloseHandle(data[i].thread);
}
/* loop over the internal handles returned in the descriptors */
ret = 0; /* number of ready file descriptors */
for(i = 0; i < nfd; i++) {
fd = data[i].fd;
handle = handles[i];
wsasock = (curl_socket_t)fd;
/* check if the current internal handle was triggered */
if(wait != WAIT_FAILED && (wait - WAIT_OBJECT_0) <= i &&
WaitForSingleObjectEx(handle, 0, FALSE) == WAIT_OBJECT_0) {
/* first handle stdin, stdout and stderr */
if(fd == fileno(stdin)) {
/* stdin is never ready for write or exceptional */
FD_CLR(wsasock, writefds);
FD_CLR(wsasock, exceptfds);
}
else if(fd == fileno(stdout) || fd == fileno(stderr)) {
/* stdout and stderr are never ready for read or exceptional */
FD_CLR(wsasock, readfds);
FD_CLR(wsasock, exceptfds);
}
else {
/* try to handle the event with the Winsock2 functions */
wsaevents.lNetworkEvents = 0;
if(WSAEnumNetworkEvents(wsasock, handle, &wsaevents) == 0) {
/* merge result from pre-check using select */
wsaevents.lNetworkEvents |= data[i].wsastate;
/* remove from descriptor set if not ready for read/accept/close */
if(!(wsaevents.lNetworkEvents & (FD_READ | FD_ACCEPT | FD_CLOSE)))
FD_CLR(wsasock, readfds);
/* remove from descriptor set if not ready for write/connect */
if(!(wsaevents.lNetworkEvents & (FD_WRITE | FD_CONNECT | FD_CLOSE)))
FD_CLR(wsasock, writefds);
/* remove from descriptor set if not exceptional */
if(!(wsaevents.lNetworkEvents & FD_OOB))
FD_CLR(wsasock, exceptfds);
}
}
/* check if the event has not been filtered using specific tests */
if(FD_ISSET(wsasock, readfds) || FD_ISSET(wsasock, writefds) ||
FD_ISSET(wsasock, exceptfds)) {
ret++;
}
}
else {
/* remove from all descriptor sets since this handle did not trigger */
FD_CLR(wsasock, readfds);
FD_CLR(wsasock, writefds);
FD_CLR(wsasock, exceptfds);
}
}
for(fd = 0; fd < nfds; fd++) {
if(FD_ISSET(fd, readfds))
logmsg("[select_ws] %d is readable", fd);
if(FD_ISSET(fd, writefds))
logmsg("[select_ws] %d is writable", fd);
if(FD_ISSET(fd, exceptfds))
logmsg("[select_ws] %d is exceptional", fd);
}
for(i = 0; i < nws; i++) {
WSAEventSelect(data[i].wsasock, NULL, 0);
WSACloseEvent(data[i].wsaevent);
}
for(i = 0; i < nth; i++) {
CloseHandle(data[i].signal);
}
CloseHandle(abort);
free(handles);
free(data);
return ret;
}
#define SOCKFILT_select(a, b, c, d, e) select_ws(a, b, c, d, e)
#else
#define SOCKFILT_select(a, b, c, d, e) select(a, b, c, d, e)
#endif /* USE_WINSOCK */
/* Perform the disconnect handshake with sockfilt
* This involves waiting for the disconnect acknowledgment after the DISC
* command, while throwing away anything else that might come in before
* that.
*/
static bool disc_handshake(void)
{
if(!write_stdout("DISC\n", 5))
return FALSE;
do {
unsigned char buffer[BUFFER_SIZE];
ssize_t buffer_len;
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("ACKD", buffer, 4)) {
/* got the ack we were waiting for */
break;
}
else if(!memcmp("DISC", buffer, 4)) {
logmsg("Crikey! Client also wants to disconnect");
if(!write_stdout("ACKD\n", 5))
return FALSE;
}
else if(!memcmp("DATA", buffer, 4)) {
/* We must read more data to stay in sync */
logmsg("Throwing away data bytes");
if(!read_data_block(buffer, sizeof(buffer), &buffer_len))
return FALSE;
}
else if(!memcmp("QUIT", buffer, 4)) {
/* just die */
logmsg("quits");
return FALSE;
}
else {
logmsg("Unexpected message error; aborting");
/*
* The only other messages that could occur here are PING and PORT,
* and both of them occur at the start of a test when nothing should be
* trying to DISC. Therefore, we should not ever get here, but if we
* do, it is probably due to some kind of unclean shutdown situation so
* us shutting down is what we probably ought to be doing, anyway.
*/
return FALSE;
}
} while(TRUE);
return TRUE;
}
/*
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;
int error = 0;
char errbuf[STRERROR_LEN];
unsigned char buffer[BUFFER_SIZE];
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 is always a socket to wait for */
FD_SET(sockfd, &fds_read);
maxfd = (int)sockfd;
break;
case PASSIVE_CONNECT:
sockfd = *sockfdp;
if(sockfd == CURL_SOCKET_BAD) {
/* 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 is always a socket to wait for */
FD_SET(sockfd, &fds_read);
maxfd = (int)sockfd;
}
break;
case ACTIVE:
sockfd = *sockfdp;
/* sockfd turns CURL_SOCKET_BAD when our connection has been closed */
if(sockfd != CURL_SOCKET_BAD) {
FD_SET(sockfd, &fds_read);
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 = SOCKFILT_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 = SOCKERRNO) == SOCKEINTR));
if(rc < 0) {
logmsg("select() failed with error (%d) %s",
error, curlx_strerror(error, errbuf, sizeof(errbuf)));
return FALSE;
}
if(rc == 0)
/* timeout */
return TRUE;
if(FD_ISSET(fileno(stdin), &fds_read)) {
ssize_t buffer_len;
/* 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-through 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]" */
snprintf((char *)buffer, sizeof(buffer), "%s/%hu\n",
ipv_inuse, server_port);
buffer_len = (ssize_t)strlen((const char *)buffer);
snprintf(data, sizeof(data), "PORT\n%04x\n", (int)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_data_block(buffer, sizeof(buffer), &buffer_len))
return FALSE;
if(buffer_len < 0)
return FALSE;
if(*mode == PASSIVE_LISTEN) {
logmsg("*** We are disconnected!");
if(!disc_handshake())
return FALSE;
}
else {
/* send away on the socket */
ssize_t 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("ACKD\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))) {
ssize_t nread_socket;
if(*mode == PASSIVE_LISTEN) {
/* there is no stream set up yet, this is an indication that there is a
client connecting. */
curl_socket_t newfd = accept(sockfd, NULL, NULL);
if(newfd == CURL_SOCKET_BAD) {
error = SOCKERRNO;
logmsg("accept() failed with error (%d) %s",
error, curlx_strerror(error, errbuf, sizeof(errbuf)));
}
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%04x\n", (int)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) {
logmsg("====> Client disconnect");
if(!disc_handshake())
return FALSE;
sclose(sockfd);
*sockfdp = CURL_SOCKET_BAD;
if(*mode == PASSIVE_CONNECT)
*mode = PASSIVE_LISTEN;
else
*mode = ACTIVE_DISCONNECT;
return TRUE;
}
}
return TRUE;
}
static int test_sockfilt(int argc, const char *argv[])
{
srvr_sockaddr_union_t me;
curl_socket_t sock = CURL_SOCKET_BAD;
curl_socket_t msgsock = CURL_SOCKET_BAD;
int wrotepidfile = 0;
int wroteportfile = 0;
bool juggle_again;
int rc;
int error;
char errbuf[STRERROR_LEN];
int arg = 1;
enum sockmode mode = PASSIVE_LISTEN; /* default */
const char *addr = NULL;
pidname = ".sockfilt.pid";
serverlogfile = "log/sockfilt.log";
server_port = 8999;
while(argc > arg) {
const char *opt;
curl_off_t num;
if(!strcmp("--version", argv[arg])) {
printf("sockfilt IPv4%s\n",
#ifdef USE_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("--portfile", argv[arg])) {
arg++;
if(argc > arg)
portname = argv[arg++];
}
else if(!strcmp("--logfile", argv[arg])) {
arg++;
if(argc > arg)
serverlogfile = argv[arg++];
}
else if(!strcmp("--ipv6", argv[arg])) {
#ifdef USE_IPV6
socket_domain = AF_INET6;
ipv_inuse = "IPv6";
#endif
arg++;
}
else if(!strcmp("--ipv4", argv[arg])) {
/* for completeness, we support this option as well */
#ifdef USE_IPV6
socket_domain = AF_INET;
ipv_inuse = "IPv4";
#endif
arg++;
}
else if(!strcmp("--bindonly", argv[arg])) {
s_bind_only = TRUE;
arg++;
}
else if(!strcmp("--port", argv[arg])) {
arg++;
if(argc > arg) {
opt = argv[arg];
if(!curlx_str_number(&opt, &num, 0xffff))
server_port = (unsigned short)num;
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) {
opt = argv[arg];
if(curlx_str_number(&opt, &num, 0xffff)) {
fprintf(stderr, "sockfilt: invalid --connect argument (%s)\n",
argv[arg]);
return 0;
}
server_connectport = (unsigned short)num;
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"
" --portfile [file]\n"
" --ipv4\n"
" --ipv6\n"
" --bindonly\n"
" --port [port]\n"
" --connect [port]\n"
" --addr [address]");
return 0;
}
}
CURL_BINMODE(stdin);
CURL_BINMODE(stdout);
CURL_BINMODE(stderr);
install_signal_handlers(false);
sock = socket(socket_domain, SOCK_STREAM, 0);
if(sock == CURL_SOCKET_BAD) {
error = SOCKERRNO;
logmsg("Error creating socket (%d) %s",
error, curlx_strerror(error, errbuf, sizeof(errbuf)));
write_stdout("FAIL\n", 5);
goto sockfilt_cleanup;
}
if(server_connectport) {
/* Active mode, we should connect to the given port number */
mode = ACTIVE;
switch(socket_domain) {
case AF_INET:
memset(&me.sa4, 0, sizeof(me.sa4));
me.sa4.sin_family = AF_INET;
me.sa4.sin_port = htons(server_connectport);
me.sa4.sin_addr.s_addr = INADDR_ANY;
if(!addr)
addr = "127.0.0.1";
curlx_inet_pton(AF_INET, addr, &me.sa4.sin_addr);
rc = connect(sock, &me.sa, sizeof(me.sa4));
break;
#ifdef USE_IPV6
case AF_INET6:
memset(&me.sa6, 0, sizeof(me.sa6));
me.sa6.sin6_family = AF_INET6;
me.sa6.sin6_port = htons(server_connectport);
if(!addr)
addr = "::1";
curlx_inet_pton(AF_INET6, addr, &me.sa6.sin6_addr);
rc = connect(sock, &me.sa, sizeof(me.sa6));
break;
#endif /* USE_IPV6 */
default:
rc = 1;
}
if(rc) {
error = SOCKERRNO;
logmsg("Error connecting to port %hu (%d) %s", server_connectport,
error, curlx_strerror(error, errbuf, sizeof(errbuf)));
write_stdout("FAIL\n", 5);
goto sockfilt_cleanup;
}
logmsg("====> Client connect");
msgsock = sock; /* use this as stream */
}
else {
/* passive daemon style */
sock = sockdaemon(sock, &server_port, NULL, s_bind_only);
if(sock == CURL_SOCKET_BAD) {
write_stdout("FAIL\n", 5);
goto sockfilt_cleanup;
}
msgsock = CURL_SOCKET_BAD; /* no stream socket yet */
}
logmsg("Running %s version", ipv_inuse);
if(server_connectport)
logmsg("Connected to port %hu", server_connectport);
else if(s_bind_only)
logmsg("Bound without listening on port %hu", server_port);
else
logmsg("Listening on port %hu", server_port);
wrotepidfile = write_pidfile(pidname);
if(!wrotepidfile) {
write_stdout("FAIL\n", 5);
goto sockfilt_cleanup;
}
if(portname) {
wroteportfile = write_portfile(portname, server_port);
if(!wroteportfile) {
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);
if(wroteportfile)
unlink(portname);
restore_signal_handlers(false);
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;
}