/*
This file is part of GNUnet.
- (C) 2010 Christian Grothoff (and other contributing authors)
+ (C) 2010, 2012 Christian Grothoff (and other contributing authors)
GNUnet is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
#include "gnunet_util_lib.h"
#include "plugin_transport_wlan.h"
-#define FIFO_FILE1 "/tmp/test-transport/api-wlan-p1/WLAN_FIFO_in"
-#define FIFO_FILE2 "/tmp/test-transport/api-wlan-p1/WLAN_FIFO_out"
+/**
+ * Name of the fifo to use for IPC with the other dummy process.
+ */
+#define FIFO_FILE1 "/tmp/test-transport/api-wlan-p1/WLAN_FIFO_in"
+
+/**
+ * Name of the fifo to use for IPC with the other dummy process.
+ */
+#define FIFO_FILE2 "/tmp/test-transport/api-wlan-p1/WLAN_FIFO_out"
+/**
+ * Maximum size of a message allowed in either direction
+ * (used for our receive and sent buffers).
+ */
#define MAXLINE 4096
-struct sendbuf
+
+/**
+ * IO buffer used for buffering data in transit.
+ */
+struct SendBuffer
{
- unsigned int pos;
- unsigned int size;
+
+ /**
+ * How many bytes that were stored in 'buf' did we already write to the
+ * destination? Always smaller than 'size'.
+ */
+ size_t pos;
+
+ /**
+ * How many bytes of data are stored in 'buf' for transmission right now?
+ * Data always starts at offset 0 and extends to 'size'.
+ */
+ size_t size;
+
+ /**
+ * Buffered data; twice the maximum allowed message size as we add some
+ * headers.
+ */
char buf[MAXLINE * 2];
};
-static int first;
+/**
+ * Flag set to 1 if we are to terminate, otherwise 0.
+ */
static int closeprog;
+
+/**
+ * We're being killed, clean up.
+ *
+ * @param sig killing signal
+ */
static void
sigfunc (int sig)
{
/**
- * function to create GNUNET_MESSAGE_TYPE_WLAN_HELPER_CONTROL message for plugin
+ * Create control message for plugin
+ *
* @param buffer pointer to buffer for the message
* @param mac pointer to the mac address
* @return number of bytes written
memcpy (&macmsg.mac, (char *) mac, sizeof (struct GNUNET_TRANSPORT_WLAN_MacAddress));
macmsg.hdr.size = htons (sizeof (struct GNUNET_TRANSPORT_WLAN_HelperControlMessage));
macmsg.hdr.type = htons (GNUNET_MESSAGE_TYPE_WLAN_HELPER_CONTROL);
-
memcpy (buffer, &macmsg, sizeof (struct GNUNET_TRANSPORT_WLAN_HelperControlMessage));
return sizeof (struct GNUNET_TRANSPORT_WLAN_HelperControlMessage);
}
+/**
+ * We got a message from the FIFO, check it, convert the message
+ * type to the output forward and copy it to the buffer for stdout.
+ *
+ * @param cls the 'struct SendBuffer' to copy the converted message to
+ * @param client unused
+ * @param hdr inbound message from the FIFO
+ */
static void
stdin_send (void *cls, void *client, const struct GNUNET_MessageHeader *hdr)
{
- struct sendbuf *write_pout = cls;
+ struct SendBuffer *write_pout = cls;
const struct GNUNET_TRANSPORT_WLAN_RadiotapSendMessage *in;
size_t payload_size;
struct GNUNET_TRANSPORT_WLAN_RadiotapReceiveMessage newheader;
if ( (GNUNET_MESSAGE_TYPE_WLAN_DATA_TO_HELPER != ntohs (hdr->type)) ||
(sizeof (struct GNUNET_TRANSPORT_WLAN_RadiotapSendMessage) > sendsize) )
{
- fprintf (stderr, "Received malformed message\n",
- (unsigned int) sendsize,
- (unsigned int) ntohs (hdr->type));
+ fprintf (stderr, "Received malformed message\n");
exit (1);
}
payload_size = sendsize - sizeof (struct GNUNET_TRANSPORT_WLAN_RadiotapSendMessage);
if ((payload_size + sizeof (struct GNUNET_TRANSPORT_WLAN_RadiotapReceiveMessage) + write_pout->size) > MAXLINE * 2)
{
- fprintf (stderr, "Packet too big for buffer\n");
+ FPRINTF (stderr, "%s", "Packet too big for buffer\n");
exit (1);
}
memset (&newheader, 0, sizeof (newheader));
}
+/**
+ * We read a full message from stdin. Copy it to our send buffer.
+ *
+ * @param cls the 'struct SendBuffer' to copy to
+ * @param client unused
+ * @param hdr the message we received to copy to the buffer
+ */
static void
file_in_send (void *cls, void *client, const struct GNUNET_MessageHeader *hdr)
{
- struct sendbuf *write_std = cls;
+ struct SendBuffer *write_std = cls;
uint16_t sendsize;
sendsize = ntohs (hdr->size);
if ((sendsize + write_std->size) > MAXLINE * 2)
{
- fprintf (stderr, "Function file_in_send: Packet too big for buffer\n");
+ FPRINTF (stderr, "%s", "Packet too big for buffer\n");
exit (1);
}
-
memcpy (write_std->buf + write_std->size, hdr, sendsize);
write_std->size += sendsize;
}
+/**
+ * Main function of a program that pretends to be a WLAN card.
+ *
+ * @param argc should be 2
+ * @param argv either '1' or '2', depending on which of the two cards this dummy is to emulate
+ * @return 1 on error, 0 if terminated normally via signal
+ */
int
main (int argc, char *argv[])
{
int fdpin;
int fdpout;
char readbuf[MAXLINE];
- int readsize = 0;
- struct sendbuf write_std;
- struct sendbuf write_pout;
- int ret = 0;
- int maxfd = 0;
+ int readsize;
+ struct SendBuffer write_std;
+ struct SendBuffer write_pout;
+ int ret;
+ int maxfd;
fd_set rfds;
fd_set wfds;
struct timeval tv;
int retval;
- struct GNUNET_SERVER_MessageStreamTokenizer *stdin_mst;
- struct GNUNET_SERVER_MessageStreamTokenizer *file_in_mst;
+ struct GNUNET_SERVER_MessageStreamTokenizer *stdin_mst = NULL;
+ struct GNUNET_SERVER_MessageStreamTokenizer *file_in_mst = NULL;
struct GNUNET_TRANSPORT_WLAN_MacAddress macaddr;
+ int first;
- if (2 != argc)
+ if ( (2 != argc) ||
+ ((0 != strcmp (argv[1], "1")) && (0 != strcmp (argv[1], "2"))) )
{
- fprintf (stderr,
- "This program must be started with the operating mode (1 or 2) as the only argument.\n");
+ FPRINTF (stderr,
+ "%s",
+ "This program must be started with the operating mode (1 or 2) as the only argument.\n");
return 1;
}
- if ((0 != strstr (argv[1], "1")) && (0 != strstr (argv[1], "2")))
- return 1;
- //make the fifos if needed
+ /* make the fifos if needed */
if (0 != stat (FIFO_FILE1, &st))
{
if (0 == stat (FIFO_FILE2, &st))
{
- fprintf (stderr, "FIFO_FILE2 exists, but FIFO_FILE1 not\n");
+ FPRINTF (stderr, "%s", "FIFO_FILE2 exists, but FIFO_FILE1 not\n");
exit (1);
}
umask (0);
erg = mkfifo (FIFO_FILE1, 0666);
if (0 != erg)
{
- fprintf (stderr, "Error in mkfifo(%s): %s\n", FIFO_FILE1,
+ FPRINTF (stderr, "Error in mkfifo(%s): %s\n", FIFO_FILE1,
strerror (errno));
- //exit(1);
}
erg = mkfifo (FIFO_FILE2, 0666);
if (0 != erg)
{
- fprintf (stderr, "Error in mkfifo(%s): %s\n", FIFO_FILE2,
+ FPRINTF (stderr, "Error in mkfifo(%s): %s\n", FIFO_FILE2,
strerror (errno));
- //exit(1);
}
-
}
else
{
if (0 != stat (FIFO_FILE2, &st))
{
- fprintf (stderr, "FIFO_FILE1 exists, but FIFO_FILE2 not\n");
+ FPRINTF (stderr, "%s", "FIFO_FILE1 exists, but FIFO_FILE2 not\n");
exit (1);
}
}
- if (strstr (argv[1], "1"))
+ if (0 != strcmp (argv[1], "1"))
{
- //fprintf(stderr, "First\n");
first = 1;
fpin = fopen (FIFO_FILE1, "r");
if (NULL == fpin)
{
- fprintf (stderr, "fopen of read FIFO_FILE1\n");
+ FPRINTF (stderr, "fopen of read FIFO_FILE1 failed: %s\n", STRERROR (errno));
goto end;
}
fpout = fopen (FIFO_FILE2, "w");
if (NULL == fpout)
{
- fprintf (stderr, "fopen of write FIFO_FILE2\n");
+ FPRINTF (stderr, "fopen of write FIFO_FILE2 failed: %s\n", STRERROR (errno));
goto end;
}
-
}
else
{
first = 0;
- //fprintf(stderr, "Second\n");
fpout = fopen (FIFO_FILE1, "w");
if (NULL == fpout)
{
- fprintf (stderr, "fopen of write FIFO_FILE1\n");
+ FPRINTF (stderr, "fopen of write FIFO_FILE1 failed: %s\n", STRERROR (errno));
goto end;
}
fpin = fopen (FIFO_FILE2, "r");
if (NULL == fpin)
{
- fprintf (stderr, "fopen of read FIFO_FILE2\n");
+ FPRINTF (stderr, "fopen of read FIFO_FILE2 failed: %s\n", STRERROR (errno));
goto end;
}
-
}
fdpin = fileno (fpin);
GNUNET_assert (fpin >= 0);
-
if (fdpin >= FD_SETSIZE)
{
- fprintf (stderr, "File fdpin number too large (%d > %u)\n", fdpin,
+ FPRINTF (stderr, "File fdpin number too large (%d > %u)\n", fdpin,
(unsigned int) FD_SETSIZE);
goto end;
}
if (fdpout >= FD_SETSIZE)
{
- fprintf (stderr, "File fdpout number too large (%d > %u)\n", fdpout,
+ FPRINTF (stderr, "File fdpout number too large (%d > %u)\n", fdpout,
(unsigned int) FD_SETSIZE);
goto end;
-
}
signal (SIGINT, &sigfunc);
stdin_mst = GNUNET_SERVER_mst_create (&stdin_send, &write_pout);
file_in_mst = GNUNET_SERVER_mst_create (&file_in_send, &write_std);
- //Send random mac address
+ /* Send 'random' mac address */
macaddr.mac[0] = 0x13;
macaddr.mac[1] = 0x22;
macaddr.mac[2] = 0x33;
while (0 == closeprog)
{
maxfd = -1;
- //set timeout
tv.tv_sec = 5;
tv.tv_usec = 0;
FD_ZERO (&rfds);
- // if output queue is empty
+ FD_ZERO (&wfds);
+ /* if output queue is empty, read */
if (0 == write_pout.size)
{
FD_SET (STDIN_FILENO, &rfds);
FD_SET (fdpin, &rfds);
maxfd = MAX (fdpin, maxfd);
}
- FD_ZERO (&wfds);
- // if there is something to write
+
+ /* if there is something to write, try to write */
if (0 < write_std.size)
{
FD_SET (STDOUT_FILENO, &wfds);
continue;
if (0 > retval)
{
- fprintf (stderr, "select failed: %s\n", strerror (errno));
+ FPRINTF (stderr, "select failed: %s\n", STRERROR (errno));
closeprog = 1;
break;
}
if (0 > ret)
{
closeprog = 1;
- fprintf (stderr, "Write ERROR to STDOUT_FILENO: %s\n",
- strerror (errno));
+ FPRINTF (stderr, "Write ERROR to STDOUT_FILENO: %s\n",
+ STRERROR (errno));
break;
}
else
{
write_std.pos += ret;
- // check if finished
+ /* check if finished writing */
if (write_std.pos == write_std.size)
{
write_std.pos = 0;
if (0 > ret)
{
closeprog = 1;
- fprintf (stderr, "Write ERROR to fdpout: %s\n", strerror (errno));
+ FPRINTF (stderr, "Write ERROR to fdpout failed: %s\n", STRERROR (errno));
}
else
{
write_pout.pos += ret;
- // check if finished
+ /* check if finished writing */
if (write_pout.pos == write_pout.size)
{
write_pout.pos = 0;
if (0 > readsize)
{
closeprog = 1;
- fprintf (stderr, "Error reading from STDIN_FILENO: %s\n",
- strerror (errno));
+ FPRINTF (stderr, "Error reading from STDIN_FILENO: %s\n",
+ STRERROR (errno));
}
else if (0 < readsize)
{
}
else
{
- //eof
+ /* eof */
closeprog = 1;
}
}
if (0 > readsize)
{
closeprog = 1;
- fprintf (stderr, "Error reading from fdpin: %s\n", strerror (errno));
+ FPRINTF (stderr, "Error reading from fdpin: %s\n", STRERROR (errno));
break;
}
else if (0 < readsize)
}
else
{
- //eof
+ /* eof */
closeprog = 1;
}
}
}
- //clean up
- GNUNET_SERVER_mst_destroy (stdin_mst);
- GNUNET_SERVER_mst_destroy (file_in_mst);
-
end:
- if (fpout != NULL)
+ /* clean up */
+ if (NULL != stdin_mst)
+ GNUNET_SERVER_mst_destroy (stdin_mst);
+ if (NULL != file_in_mst)
+ GNUNET_SERVER_mst_destroy (file_in_mst);
+
+ if (NULL != fpout)
fclose (fpout);
- if (fpin != NULL)
+ if (NULL != fpin)
fclose (fpin);
if (1 == first)
{
* interface. It will force traffic to be in 'ad-hoc' mode, use the
* proper MAC address of the WLAN interface and use a GNUnet-specific
* SSID (and a GNUnet-specific SNAP header). It only takes a single
- * argument, which is the name of the interface to use. Since it uses
- * RAW sockets, it must be installed SUID or run as 'root'. In order
- * to keep the security risk of the resulting SUID binary minimal, the
- * program ONLY opens the RAW socket with root privileges, then drops
- * them and only then starts to process command line arguments. The
- * code also does not link against any shared libraries (except libc)
- * and is strictly minimal (except for checking for errors). The
- * following list of people have reviewed this code and considered it
- * safe since the last modification (if you reviewed it, please have
- * your name added to the list):
+ * argument, which is the name of the WLAN interface to use. The
+ * program detects if the interface is not a WLAN interface and exits
+ * with an error in that case.
*
- * - Christian Grothoff (Mar 16th 2012)
+ * Once initialized, the program will first send a 'struct
+ * GNUNET_TRANSPORT_WLAN_HelperControlMessage' to 'stdout'. That
+ * message contains the MAC address of the WLAN interface. It will
+ * then read messages from the WLAN interface and send them together
+ * with performance information as 'struct
+ * GNUNET_TRANSPORT_WLAN_RadiotapReceiveMessage' messages to 'stdout'.
+ * Furthermore, it will read a stream of messages from 'stdin' that
+ * have the format from 'struct
+ * GNUNET_TRANSPORT_WLAN_RadiotapSendMessage'. Those messages will
+ * then be sent via the WLAN interface; however, the sender MAC
+ * address will be forced to be the correct address from our WLAN
+ * card. If 'stdin' closes, receiving from the WLAN interface will
+ * continue. If 'stdout' causes a SIGPIPE, the process dies from the
+ * signal. Errors cause an error message to be reported to 'stderr',
+ * in most cases the process also exits (with status code '1'). The
+ * program never terminates normally; it is safe to kill the
+ * process with SIGTERM or SIGKILL at any time.
+ *
+ * Since it uses RAW sockets, the binary must be installed SUID or run
+ * as 'root'. In order to keep the security risk of the resulting
+ * SUID binary minimal, the program ONLY opens the RAW socket with
+ * root privileges, then drops them and only then starts to process
+ * command line arguments. The code also does not link against any
+ * shared libraries (except libc) and is strictly minimal (except for
+ * checking for errors). The following list of people have reviewed
+ * this code and considered it safe since the last modification (if
+ * you reviewed it, please have your name added to the list):
+ *
+ * - Christian Grothoff (Apr 3rd 2012)
*/
/*-
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