path: root/echld/dispatcher.c

/* echld_dispatcher.c
 *  epan working child API internals
 *  Dispatcher process routines and definitions
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * Copyright (c) 2013 by Luis Ontanon <luis@ontanon.org>
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "echld-int.h"
/**
  DISPATCHER
  **/

struct dispatcher_child {
	echld_chld_id_t chld_id;
	child_state_t state;
	echld_reader_t reader;
	int write_fd;
	int pid;
	int reqh_id;
	gboolean closing;
};

struct dispatcher {
	int parent_out;
	echld_reader_t parent_in;
	struct dispatcher_child* children;
	int max_children;
	int nchildren;
	int reqh_id;
	int pid;
	int ppid;
	struct _encs {
		child_encoder_t* to_parent;
		echld_parent_encoder_t* to_child;
	} enc;
	struct _decs {
		child_decoder_t* from_parent;
		parent_decoder_t* from_child;
	} dec;

	int dumpcap_pid;
	gboolean closing;
	capture_options capture_opts;
};

struct dispatcher* dispatcher;

#ifdef DEBUG_DISPATCHER
static int debug_lvl = DEBUG_DISPATCHER;
static FILE* debug_fp = NULL;

#define DCOM() /*echld_common_set_dbg(debug_lvl,debug_fp,"Disp")*/

int dispatcher_debug(int level, const char* fmt, ...) {
	va_list ap;
	char* str;

	if (debug_lvl<level) return 1;

	va_start(ap, fmt);
	str = g_strdup_vprintf(fmt,ap);
	va_end(ap);

	if (dispatcher) {
		fprintf(debug_fp, "dispatcher[%d]: reqh_id=%d dbg_level=%d message='%s'\n", dispatcher->pid, dispatcher->reqh_id, level, str);
	} else {
		fprintf(debug_fp, "dispatcher: dbg_level=%d message='%s'\n", level, str);
	}

	fflush(debug_fp);

	g_free(str);

	return 1;
}


static char* param_get_dbg_level(char** err _U_) {
	return g_strdup_printf("%d",debug_lvl);
}

static echld_bool_t param_set_dbg_level(char* val , char** err ) {
	char* p;
	int lvl = (int)strtol(val, &p, 10);

	if (p<=val) {
		*err = g_strdup("not an integer");
		return FALSE;
	} else if (lvl < 0 || lvl > 5) {
		*err = g_strdup_printf("invalid level=%d (min=0 max=5)",lvl);
		return FALSE;
	}

	debug_lvl = lvl;
	DCOM();
	return TRUE;
}

static long dbg_r = 0;

#define DISP_DBG(attrs) ( dispatcher_debug attrs )
#define DISP_DBG_INIT() do { debug_fp = stderr;  DCOM(); } while(0)
#define DISP_DBG_START(fname) do { debug_fp = fopen(fname,"a"); DCOM(); DISP_DBG((0,"Log Started"));  } while(0)
#define DISP_WRITE(FD,BA,CH,T,RH) ( dbg_r = echld_write_frame(FD,BA,CH,T,RH,NULL), DISP_DBG((1,"SND fd=%d ch=%d ty='%s' rh=%d msg='%s'",FD,CH,TY(T),RH, (dbg_r>0?"ok":strerror(errno)))), dbg_r )
#define CHLD_SET_STATE(c,st) do { DISP_DBG((1,"Child[%d] State %s => %s",(c)->chld_id, ST((c)->state), ST((st)) )); (c)->state=(st); } while(0)
#else
#define DISP_DBG(attrs)
#define DISP_DBG_INIT()
#define DISP_DBG_START(fname)
#define DISP_WRITE(FD,BA,CH,T,RH) echld_write_frame(FD,BA,CH,T,RH,NULL)
#define CHLD_SET_STATE(c,st) ((c)->state = (st))
#endif

#define DISP_RESP(B,T) (DISP_WRITE( dispatcher->parent_out, (B), 0, (T), dispatcher->reqh_id))



static echld_epan_stuff_t stuff;

static void init_stuff(void) {
#ifdef HAVE_LIBPCAP
	capture_opts_init(&stuff.cap_opts);
	capture_session_init(&stuff.cap_sess, (void *)&stuff.cfile);
#endif

}

static void children_massacre(void) {
	int i;
	struct dispatcher_child* cc = dispatcher->children;
	int max_children = dispatcher->max_children;

	for(i = 0; i < max_children; i++) {
		struct dispatcher_child* c = &(cc[i]);
		if (c->pid > 0) {
			DISP_DBG((0,"killing ch=%d pid=%d",c->chld_id,c->pid));
			kill(c->pid,SIGTERM);
		}
	}
}


static void dispatcher_fatal(int cause, const char* fmt, ...) {
	size_t len= 1024;
	gchar err_str[len];
	va_list ap;

	va_start(ap, fmt);
	g_vsnprintf(err_str,len,fmt,ap);
	va_end(ap);

	DISP_DBG((0,"fatal cause=%d msg=\"%s\"",cause ,err_str));

	children_massacre();

	exit(cause);
}

#define DISP_FATAL(attrs) dispatcher_fatal attrs

static void dispatcher_err(int errnum, const char* fmt, ...) {
	size_t len= 1024;
	gchar err_str[len];
	va_list ap;
	static GByteArray* ba;

	va_start(ap, fmt);
	g_vsnprintf(err_str,len,fmt,ap);
	va_end(ap);

	DISP_DBG((0,"error=\"%s\"",err_str));

	ba = dispatcher->enc.to_parent->error(errnum, err_str);
	DISP_RESP(ba,ECHLD_ERROR);
	g_byte_array_free(ba,TRUE);
}

/* parameters */

/* interface listing */

static char* intflist2json(GList* if_list, char** if_cap_err) {
#define ADDRSTRLEN 46 /* Covers IPv4 & IPv6 */

    GList       *if_entry;
    if_info_t   *if_info;
    GSList      *addr;
    if_addr_t   *if_addr;
    if_capabilities_t *caps;
    char        addr_str[ADDRSTRLEN];
    GString     *str = g_string_new("{ what='interfaces', interfaces={ \n");
    char* s;

    for (if_entry = g_list_first(if_list); if_entry != NULL;
         if_entry = g_list_next(if_entry)) {
        if_info = (if_info_t *)if_entry->data;
        g_string_append_printf(str,"  %s={ intf='%s',", if_info->name, if_info->name);

        /*
         * Print the contents of the if_entry struct in a parseable format.
         * Each if_entry element is tab-separated.  Addresses are comma-
         * separated.
         */
        /* XXX - Make sure our description doesn't contain a tab */
        if (if_info->vendor_description != NULL)
            g_string_append_printf(str," vnd_desc='%s',", if_info->vendor_description);

        /* XXX - Make sure our friendly name doesn't contain a tab */
        if (if_info->friendly_name != NULL)
            g_string_append_printf(str," name='%s', addrs=[ ", if_info->friendly_name);

        for (addr = g_slist_nth(if_info->addrs, 0); addr != NULL;
                    addr = g_slist_next(addr)) {

            if_addr = (if_addr_t *)addr->data;
            switch(if_addr->ifat_type) {
            case IF_AT_IPv4:
                if (inet_ntop(AF_INET, &if_addr->addr.ip4_addr, addr_str,
                              ADDRSTRLEN)) {
                    g_string_append_printf(str,"'%s',", addr_str);
                } else {
                    g_string_append(str,"'<unknown IPv4>',");
                }
                break;
            case IF_AT_IPv6:
                if (inet_ntop(AF_INET6, &if_addr->addr.ip6_addr,
                              addr_str, ADDRSTRLEN)) {
                    g_string_append_printf(str,"'%s',", addr_str);
                } else {
                    g_string_append(str,"'<unknown IPv6>',");
                }
                break;
            default:
                g_string_append_printf(str,"'<type unknown %u>',", if_addr->ifat_type);
            }

        }

	    g_string_truncate(str,str->len - 1); /* the last comma or space (on empty list) */
        g_string_append(str," ]"); /* addrs */


        if (if_info->loopback)
            g_string_append(str,", loopback=1");
        else
            g_string_append(str,", loopback=0");



		caps = capture_get_if_capabilities(if_info->name, 0, if_cap_err, NULL);

		if (caps != NULL) {
			if (caps->data_link_types != NULL) {
				GList* lt_entry = caps->data_link_types;
			    data_link_info_t *data_link_info;

				g_string_append(str,", data_link_types=[");

				for (; lt_entry != NULL; lt_entry = g_list_next(lt_entry) ) {

				    data_link_info = (data_link_info_t *)lt_entry->data;
				    g_string_append_printf(str,"{ name='%s', desc='%s' }, ", data_link_info->name, (data_link_info->description) ? data_link_info->description : "" );
				}

				g_string_truncate(str,str->len - 2); /* the comma and space */
				g_string_append(str,"]");
			}

			g_string_append_printf(str,", can_set_rfmon=%s", caps->can_set_rfmon ? "1" : "0");

			if (caps->can_set_rfmon) {
				free_if_capabilities(caps);
				caps = capture_get_if_capabilities(if_info->name, 1, if_cap_err, NULL);

				if (caps->data_link_types != NULL) {
					GList* lt_entry = caps->data_link_types;
					data_link_info_t *data_link_info;

					g_string_append(str,", data_link_types_rfmon=[");

					for (; lt_entry != NULL; lt_entry = g_list_next(lt_entry)) {
					    data_link_info = (data_link_info_t *)lt_entry->data;
					    g_string_append_printf(str,"{ name='%s', desc='%s' }, ", data_link_info->name, (data_link_info->description) ? data_link_info->description : "" );
					}

				    g_string_truncate(str,str->len - 2); /* the comma and space */
					g_string_append(str,"]");
				}
			}

			free_if_capabilities(caps);
		}

        g_string_append(str,"},\n");
    }

    g_string_truncate(str,str->len - 2); /* the comma and return */
    g_string_append(str,"}");

    s=str->str;
    g_string_free(str,FALSE);
    return s;
}

static char* intf_list = NULL;

static void get_interfaces(char** err) {
	int err_no = 0;
	GList* if_list;

	err = NULL;
	if_list = capture_interface_list(&err_no, err, NULL);

	if (err) {
		DISP_DBG((1,"Could not get capture interface list: %s",err));
	} else {
		intf_list = intflist2json(if_list,err);
		if (err) {
			DISP_DBG((1,"get capabilities error: %s",err));
		}
	}

	free_interface_list(if_list);
}


static char* param_get_interfaces(char** err _U_) {
	return g_strdup(intf_list ? intf_list : "");
}

static long disp_loop_timeout_usec = DISPATCHER_WAIT_INITIAL;

static char* param_get_loop_timeout(char** err _U_) {
	return g_strdup_printf("%fs", (((float)disp_loop_timeout_usec)/1000000.0) );
}

static echld_bool_t param_set_loop_timeout(char* val , char** err ) {
	char* p;
	int usec = (int)strtol(val, &p, 10); /* now usecs  2DO: "10ms" or "500us" or "1s" */

	if (p<=val) {
		*err = g_strdup("not an integer");
		return FALSE;
	}

	disp_loop_timeout_usec = usec;

	return TRUE;
}

static GString *comp_info_str;
static GString *runtime_info_str;
static const char* version_str = "Echld " VERSION;
static char* version_long_str = NULL;


static char* param_get_long_version(char** err _U_) {
	return g_strdup(version_long_str);
}

static char* param_get_version(char** err _U_) {
	return g_strdup(version_str);
}

static char* param_get_capture_types(char** err _U_) {
  GString* str = g_string_new("");
  char* s;
  int i;

  for (i = 0; i < WTAP_NUM_FILE_TYPES_SUBTYPES; i++) {
    if (wtap_dump_can_open(i)) {
      g_string_append_printf(str,"%s: %s\n",
	wtap_file_type_subtype_short_string(i), wtap_file_type_subtype_string(i));
    }
  }

  s = str->str;
  g_string_free(str,FALSE);
  return s;
}

static echld_bool_t param_set_add_hosts_file(char* val, char** err) {
	if (add_hosts_file(val)) {
		return TRUE;
	} else {
		*err = g_strdup_printf("Can't read host entries from \"%s\"",val);
		return FALSE;
	}
}

static echld_bool_t param_set_x_opt(char* val, char** err) {
	if (ex_opt_add(val)) {
		return TRUE;
	} else {
		*err = g_strdup_printf("Cannot set X opt '%s'",val);
		return FALSE;
	}
}




static char* param_get_params(char** err _U_);

static param_t disp_params[] = {
#ifdef DEBUG_DISPATCHER
	PARAM(dbg_level,"0>int>5"),
# endif
	RO_PARAM(long_version,"long version string"),
	RO_PARAM(version,"version string"),
	PARAM(loop_timeout,"main loop step timeout"),
	RO_PARAM(interfaces,"interface information"),
	RO_PARAM(capture_types,"the available capture types"),
	WO_PARAM(add_hosts_file,"Add a hosts file"),
	WO_PARAM(x_opt,"Set a -X option"),
	RO_PARAM(params,"This List"),
	{NULL,NULL,NULL,NULL}
};

static char* param_get_params(char** err _U_) {
	return paramset_get_params_list(disp_params,PARAM_LIST_FMT);
}

static struct dispatcher_child* dispatcher_get_child(struct dispatcher* d, int chld_id) {
	int i;
	struct dispatcher_child* cc = d->children;
	int max_children = d->max_children;

	for(i = 0; i < max_children; i++) {
		struct dispatcher_child* c = &(cc[i]);
		if (c->chld_id == chld_id) return c;
	}

	return NULL;
}


static void dispatcher_clear_child(struct dispatcher_child* c) {
	echld_reset_reader(&(c->reader), -1, 4096);
	c->chld_id = -1;
	c->state = FREE;
	c->reader.fd = -1;
	c->write_fd = -1;
	c->pid = -1;
	c->reqh_id = -1;
	c->closing = FALSE;
}

static void set_dumpcap_pid(int pid) {

	dispatcher->dumpcap_pid = pid;
}

static void preinit_epan(char* argv0, int (*main)(int, char **)) {
	// char *gpf_path, *pf_path;
	char *gdp_path, *dp_path;
	// int gpf_open_errno, gpf_read_errno;
	// int pf_open_errno, pf_read_errno;
	int gdp_open_errno, gdp_read_errno;
	int dp_open_errno, dp_read_errno;
	char* error;

	error = init_progfile_dir(argv0, main);

	comp_info_str = g_string_new("Compiled ");
	get_compiled_version_info(comp_info_str, NULL, epan_get_compiled_version_info);

	runtime_info_str = g_string_new("Running ");
	get_runtime_version_info(runtime_info_str, NULL);

	version_long_str = g_strdup_printf("%s%s\n%s\n%s\n%s",
		version_str, wireshark_gitversion, get_copyright_info(),
		comp_info_str->str, runtime_info_str->str);

	if (error) {
		DISP_FATAL((CANNOT_PREINIT_EPAN,"Failed epan_preinit: msg='%s'",error));
	}

	 /* Add it to the information to be reported on a crash. */
	ws_add_crash_info("Echld %s\n%s\n%s",
		ws_get_version_info(), comp_info_str->str, runtime_info_str->str);

	init_stuff();

	capture_sync_set_fetch_dumpcap_pid_cb(set_dumpcap_pid);

	init_process_policies();

	get_interfaces(&error);

	if (error) {
		DISP_FATAL((CANNOT_PREINIT_EPAN,"Error getting interfaces: %s", error));
	}

	prefs_apply_all();

	/* disabled protocols as per configuration file */
	set_disabled_protos_list();


	setlocale(LC_ALL, "");
	DISP_DBG((1,"---5"));

	read_disabled_protos_list(&gdp_path, &gdp_open_errno, &gdp_read_errno, &dp_path, &dp_open_errno, &dp_read_errno);

	DISP_DBG((1,"---6"));

	cap_file_init(&stuff.cfile);
	DISP_DBG((1,"---7"));

	DISP_DBG((1,"---8"));
    timestamp_set_precision(TS_PREC_AUTO_USEC);

	// sleep(10);

	// initialize_funnel_ops();
	// stuff.prefs = read_prefs(&gpf_open_errno, &gpf_read_errno, &gpf_path, &pf_open_errno, &pf_read_errno, &pf_path);
	// check 4 errors


	DISP_DBG((2,"epan preinit done"));
}


static void dispatcher_clear(void) {
	DISP_DBG((2,"dispatcher_clear"));
	/* remove unnecessary stuff for the working child */
	/* remove signal handlers */
}

void dispatcher_sig(int sig) {
	DISP_FATAL((TERMINATED,"SIG sig=%d",sig));
	exit(1);
}

void dispatcher_reaper(int sig) {
    int    status;
	int i;
	struct dispatcher_child* cc = dispatcher->children;
	int max_children = dispatcher->max_children;
	int pid =  waitpid(-1, &status, WNOHANG);
	int reqh_id_save =	dispatcher->reqh_id;

	dispatcher->reqh_id = 0;

	if (sig != SIGCHLD) {
		DISP_DBG((1,"Reaper got wrong signal=%d",sig));
		dispatcher->reqh_id = reqh_id_save;
		return;
	}

	DISP_DBG((2,"Child dead pid=%d",pid));

	for(i = 0; i < max_children; i++) {
		struct dispatcher_child* c = &(cc[i]);
		if ( c->pid == pid ) {
			if (c->closing || dispatcher->closing) {
				DISP_WRITE(dispatcher->parent_out, NULL, c->chld_id, ECHLD_CLOSING, c->reqh_id);
			} else {
				char* s = NULL;
				GByteArray* em;

				if (WIFEXITED(status)) {
				    s = g_strdup_printf(
						"Unexpected dead: reason='exited' pid=%d status=%d",
						pid, WEXITSTATUS(status));
				} else if ( WIFSIGNALED(status) ) {
				    s = g_strdup_printf(
					"Unexpected dead: reason='signaled' pid=%d termsig=%d coredump=%s",
					pid, WTERMSIG(status), WCOREDUMP(status) ? "yes":"no");

					/*if (WCOREDUMP(status)) { system("analyze_coredump.sh pid=%d") } */

				} else if (WIFSTOPPED(status)) {
				    s = g_strdup_printf(
					"Unexpected dead: reason='stopped' pid=%d stopsig=%d",
					pid, WSTOPSIG(status));
				}

				em = dispatcher->enc.to_parent->child_dead(s);
				dispatcher_err(ECHLD_ERR_CRASHED_CHILD, s);
				if (s) g_free(s);
				DISP_WRITE(dispatcher->parent_out, em, c->chld_id, ECHLD_CHILD_DEAD, 0);
				if (em) g_byte_array_free(em,TRUE);
			}

			CHLD_SET_STATE(c,CLOSED);
			dispatcher_clear_child(c);
			dispatcher->reqh_id = reqh_id_save;
			return;
		}
	}

	if (pid == dispatcher->dumpcap_pid) {
		dispatcher->dumpcap_pid = 0;
		dispatcher->reqh_id = reqh_id_save;
		DISP_DBG((2,"dumpcap dead pid=%d",pid));
		return;
	}

	dispatcher_err(ECHLD_ERR_UNKNOWN_PID, "Unknown child pid: %d", pid);
	dispatcher->reqh_id = reqh_id_save;
}


static void dispatcher_destroy(void) {
	/* destroy the dispatcher stuff at closing */

	dispatcher->closing = TRUE;

	children_massacre();

	exit(0);
}

/* stuff coming from child going to parent */
static long dispatch_to_parent(guint8* b, size_t len, echld_chld_id_t chld_id, echld_msg_type_t type, echld_reqh_id_t reqh_id, void* data) {
	/* TODO: timeouts, clear them */
	/* TODO: keep stats */

	GByteArray in_ba;

	struct dispatcher_child* c = (struct dispatcher_child*)data;

	dispatcher->reqh_id = c->reqh_id = reqh_id;

	in_ba.data = b;
	in_ba.len = (guint)len;

	if (chld_id != c->chld_id) {
		goto misbehabing;
	}

	switch(type) {
		case ECHLD_ERROR: break;
		case ECHLD_TIMED_OUT: break;
		case ECHLD_HELLO: CHLD_SET_STATE(c,IDLE); break;
		case ECHLD_CLOSING:
			c->closing = TRUE;
			CHLD_SET_STATE(c,CLOSING);
			break;
		case ECHLD_PARAM: break;
		case ECHLD_PONG: break;
		case ECHLD_FILE_OPENED: CHLD_SET_STATE(c,READING); break;
		case ECHLD_INTERFACE_OPENED: CHLD_SET_STATE(c,READY); break;
		case ECHLD_CAPTURE_STARTED: CHLD_SET_STATE(c,CAPTURING); break;
		case ECHLD_NOTIFY: break;
		case ECHLD_PACKET_SUM: break;
		case ECHLD_TREE: break;
		case ECHLD_BUFFER: break;

		case ECHLD_EOF:
		case ECHLD_CAPTURE_STOPPED: CHLD_SET_STATE(c,DONE); break;

		case ECHLD_NOTE_ADDED: break;
		case ECHLD_PACKET_LIST: break;
		case ECHLD_FILE_SAVED: break;

		default:
			goto misbehabing;
	}

	DISP_DBG((4,"Dispatching to parent reqh_id=%d chld_id=%d type='%c'",reqh_id,c->chld_id,type));
	return DISP_WRITE(dispatcher->parent_out, &in_ba, chld_id, type, reqh_id);

misbehabing:
	CHLD_SET_STATE(c,ERRORED);
	c->closing = TRUE;
	kill(c->pid,SIGTERM);
	dispatcher_err(ECHLD_ERR_CRASHED_CHILD,"chld_id=%d",chld_id);
	return 0;

}

static struct timeval start_wait_time;
static long start_wait_time_us = CHILD_START_WAIT_TIME;

static void detach_new_child(enc_msg_t* em,  echld_chld_id_t chld_id) {
	struct dispatcher_child* c;
	int reqh_id = dispatcher->reqh_id;
	int pid;

	if (( c = dispatcher_get_child(dispatcher, chld_id) )) {
		dispatcher_err(ECHLD_ERR_CHILD_EXISTS,"chld_id=%d exists already while creating new child",chld_id);
		return;
	} else if (( c = dispatcher_get_child(dispatcher, -1) )) {
		int disp_pipe_fds[2];
		int child_pipe_fds[2];

		int pipe_to_disp;
		int pipe_from_disp;
		int pipe_to_child;
		int pipe_from_child;

		DISP_DBG((5,"new_child pipe(dispatcher)"));
		if( pipe(disp_pipe_fds) < 0) {
			dispatcher_err(ECHLD_ERR_CANNOT_FORK,"CANNOT OPEN PARENT PIPE: %s",strerror(errno));
			return;
		}

		pipe_from_disp = disp_pipe_fds[0];
		pipe_to_child = disp_pipe_fds[1];

		DISP_DBG((5,"new_child pipe(child)"));
		if( pipe(child_pipe_fds) < 0) {
			close(pipe_from_disp);
			close(pipe_to_child);
			dispatcher_err(ECHLD_ERR_CANNOT_FORK,"CANNOT OPEN CHILD PIPE: %s",strerror(errno));
			return;
		}

		pipe_from_child = child_pipe_fds[0];
		pipe_to_disp = child_pipe_fds[1];

		DISP_DBG((4,"New Child Forking()"));
		switch (( pid = fork() )) {
			case -1: {
				close(pipe_to_child);
				close(pipe_to_disp);
				close(pipe_from_child);
				close(pipe_from_disp);
				dispatcher_err(ECHLD_ERR_CANNOT_FORK,"CANNOT FORK: %s",strerror(errno));
				return;
			}
			case 0: {
			/* I'm the child */
				dispatcher_clear();

				close(pipe_to_child);
				close(pipe_from_child);

				echld_child_initialize(chld_id, pipe_from_disp,pipe_to_disp,reqh_id,&stuff);

				exit( echld_child_loop() );

				/* it won't */
				return;
			}
			default: {
			/* I'm the parent */

				close(pipe_to_disp);
				close(pipe_from_disp);

				echld_reset_reader(&(c->reader), pipe_from_child,4096);
				c->write_fd = pipe_to_child;
				c->pid = pid;
				c->chld_id = chld_id;
				c->closing = FALSE;

				CHLD_SET_STATE(c,CREATING);

				DISP_DBG((4,"Child Forked pid=%d chld_id=%d from_fd=%d to_fd=%d",
				pid, c->chld_id, pipe_from_child, pipe_to_child));

				start_wait_time.tv_sec = (int)(start_wait_time_us / 1000000);
				start_wait_time.tv_usec = (int)(start_wait_time_us % 1000000);

				select(0,NULL,NULL,NULL,&start_wait_time);

				/* configure child */
				DISP_WRITE(pipe_to_child, em, c->chld_id, ECHLD_NEW_CHILD, dispatcher->reqh_id);
				return;
			}
		}
	} else {
		dispatcher_err(ECHLD_ERR_CANNOT_FORK, "MAX CHILDREN REACHED: max_children=%d",dispatcher->max_children);
		return;
	}
}


/* process signals sent from parent */
static long dispatch_to_child(guint8* b, size_t len, echld_chld_id_t chld_id, echld_msg_type_t type, echld_reqh_id_t reqh_id, void* data _U_) {
	GByteArray in_ba;

	in_ba.data = b;
	in_ba.len = (guint)len;

	dispatcher->reqh_id = reqh_id;

	DISP_DBG((1,"RCV<- type='%s' chld_id=%d reqh_id=%d",TY(type),chld_id,reqh_id));

	if (chld_id == 0) { /* these are messages sent to the dispatcher itself */
		DISP_DBG((2,"Message to Dispatcher"));
		switch(type) {
			case ECHLD_CLOSE_CHILD:
				dispatcher_destroy();
				return 0;
			case ECHLD_PING:
				DISP_DBG((2,"PONG reqh_id=%d",reqh_id));
				DISP_WRITE(dispatcher->parent_out, NULL, chld_id, ECHLD_PONG, reqh_id);
				return 0;
			case ECHLD_SET_PARAM:{
				char* param;
				char* value;
				if ( dispatcher->dec.from_parent->set_param(b,len,&param,&value) ) {
					GByteArray* ba;
					char* err;
					if (! paramset_apply_set (disp_params, param, value, &err) ) {
						dispatcher_err(ECHLD_CANNOT_SET_PARAM,"%s",err);
						g_free(err);
						return 0;
					}

					ba = dispatcher->enc.to_parent->param(param,value);
					DISP_RESP(ba,ECHLD_PARAM);
					g_byte_array_free(ba,TRUE);
					DISP_DBG((1,"Set Param: param='%s' value='%s'",param,value));

					return 0;
				} else {
					dispatcher_err(ECHLD_CANNOT_SET_PARAM,"reason='decoder error'");
					return 0;
				}
			}
			case ECHLD_GET_PARAM: {
				GByteArray* ba;
				char* param;
				if ( dispatcher->dec.from_parent->get_param(b,len,&param) ) {
					char* err;
					char* val;

					if (! (val = paramset_apply_get (disp_params, param, &err)) ) {
						dispatcher_err(ECHLD_CANNOT_GET_PARAM,"%s",err);
						g_free(err);
						return 0;
					}

					ba = dispatcher->enc.to_parent->param(param,val);
					DISP_RESP(ba,ECHLD_PARAM);
					g_byte_array_free(ba,TRUE);
					DISP_DBG((1,"Get Param: param='%s' value='%s'",param,val));
					return 0;
				} else {
					dispatcher_err(ECHLD_CANNOT_GET_PARAM,"reason='decoder error'");
					return 0;
				}
			}
			default:
				dispatcher_err(ECHLD_ERR_WRONG_MSG, "wrong message to dispatcher type='%c'", type);
				return 0;
		}
	} else {
		struct dispatcher_child* c;

		DISP_DBG((2,"Parent => Child"));

		if (! (c = dispatcher_get_child(dispatcher, chld_id)) ) {
			if (type == ECHLD_NEW_CHILD) {
				detach_new_child(&in_ba,chld_id);
				return 0;
			} else {
				dispatcher_err(ECHLD_ERR_NO_SUCH_CHILD, "wrong chld_id %d", chld_id);
				return 0;
			}
		} else {
			switch(type) {
				case ECHLD_CLOSE_CHILD:
					CHLD_SET_STATE(c,CLOSED);
					goto relay_frame;

				case ECHLD_OPEN_FILE:
					CHLD_SET_STATE(c,READING);
					goto relay_frame;

				case ECHLD_OPEN_INTERFACE:
					CHLD_SET_STATE(c,READY);
					goto relay_frame;

				case ECHLD_START_CAPTURE:
					CHLD_SET_STATE(c,CAPTURING);
					goto relay_frame;

				case ECHLD_STOP_CAPTURE:
					CHLD_SET_STATE(c,DONE);
					goto relay_frame;

				case ECHLD_SAVE_FILE:
				case ECHLD_APPLY_FILTER:
				case ECHLD_SET_PARAM:
				case ECHLD_GET_PARAM:
				case ECHLD_PING:
				case ECHLD_GET_SUM:
				case ECHLD_GET_TREE:
				case ECHLD_GET_BUFFER:
				case ECHLD_ADD_NOTE:
				relay_frame: {
					DISP_DBG((3,"Relay to Child chld_id=%d type='%c' req_id=%d",chld_id, type, reqh_id));
					return DISP_WRITE(c->write_fd, &in_ba, chld_id, type, reqh_id);
				}
				default:
					dispatcher_err(ECHLD_ERR_WRONG_MSG, "wrong message %d %c", reqh_id, type);
					return 0;
			}
		}
	}
}



int dispatcher_loop(void) {
	int parent_out = dispatcher->parent_out;
	int parent_in = dispatcher->parent_in.fd;
	struct dispatcher_child* children = dispatcher->children;

	DISP_DBG((5,"LOOP in_fd=%d out_fd=%d",parent_in, parent_out));

	do {
		fd_set rfds;
		fd_set efds;
		struct dispatcher_child* c;
		int nfds;
		int nchld = 0;
		struct timeval disp_loop_timeout;

		FD_ZERO(&rfds);
		FD_ZERO(&efds);

		FD_SET(parent_in,&rfds);
		FD_SET(parent_in,&efds);
		FD_SET(parent_out,&efds);

		for (c = children; c->pid; c++) {
			if (c->chld_id > 0) {
				nchld++;
				FD_SET(c->reader.fd, &rfds);
				FD_SET(c->reader.fd, &efds);
			}
		}

		DISP_DBG((4,"Select()ing nchld=%d",nchld,disp_loop_timeout.tv_usec));

		disp_loop_timeout.tv_sec = (int)(disp_loop_timeout_usec / 1000000);
		disp_loop_timeout.tv_usec = (int)(disp_loop_timeout_usec % 1000000);

		nfds = select(FD_SETSIZE, &rfds, NULL, &efds, &disp_loop_timeout);

		DISP_DBG((5,"Select()ed nfds=%d",nchld,nfds));

		if (nfds < 0) {
			DISP_DBG((1,"select error='%s'",strerror(errno) ));
			continue;
		}

		if ( FD_ISSET(parent_in, &rfds)) {
			long st = echld_read_frame(&(dispatcher->parent_in), dispatch_to_child, dispatcher);

			if (st < 0) {
				DISP_DBG((1,"read frame returning < 0 for parent"));
				/* XXX: ??? */
				continue;
			}
		}

		if ( FD_ISSET(parent_in, &efds) ) {
			DISP_DBG((1,"Parent In Pipe Errored!"));
			continue;
		}

		if ( FD_ISSET(parent_out, &efds) ) {
			DISP_DBG((1,"Parent Out Pipe Errored!"));
			continue;
		}


		for (c=children; c->pid; c++) {
			if (c->reader.fd > 0) {
				if ( FD_ISSET(c->reader.fd,&efds) ) {
					struct timeval wait_time;
					wait_time.tv_sec = 0;
					wait_time.tv_usec = DISP_KILLED_CHILD_WAIT;

					DISP_DBG((1,"errored child pipe chld_id=%d",c->chld_id));
					kill(c->pid,SIGTERM);
					select(0,NULL,NULL,NULL,&wait_time);
					dispatcher_clear_child(c);
					continue;
				}

				if (FD_ISSET(c->reader.fd,&rfds)) {
					long st = echld_read_frame(&(c->reader), dispatch_to_parent, c);

					if (st < 0) {
						DISP_DBG((1,"read_frame returned < 0 for chld_id=%d",c->chld_id));
						/* XXX */
						continue;
					}
					continue;
				}
			}
		}
	} while(1);

	/* won't */
	return 1;
}

void dispatcher_alrm(int sig _U_) {
	DISP_DBG((1,"ALRM received"));
}

void echld_dispatcher_start(int* in_pipe_fds, int* out_pipe_fds, char* argv0, int (*main)(int, char **)) {
	static struct dispatcher d;
	int i;

	DISP_DBG_INIT();
	DISP_DBG((2,"Dispatcher Starting"));


	signal(SIGCHLD,dispatcher_reaper);

	signal(SIGTERM,dispatcher_sig);
	signal(SIGPIPE,dispatcher_sig);
	signal(SIGINT,SIG_IGN);
	signal(SIGCONT,SIG_IGN);
	signal(SIGABRT,dispatcher_sig);
	signal(SIGHUP,dispatcher_sig);
	signal(SIGALRM,dispatcher_alrm);

	dispatcher = &d;

	echld_init_reader(&(d.parent_in),in_pipe_fds[0],4096);
	d.parent_out = out_pipe_fds[1];
	d.children = g_new0(struct dispatcher_child,ECHLD_MAX_CHILDREN);
	d.max_children = ECHLD_MAX_CHILDREN;
	d.nchildren = 0;
	d.reqh_id = -1;
	d.pid = getpid();
	d.dumpcap_pid = 0;

	for (i=0;i<ECHLD_MAX_CHILDREN;i++) dispatcher_clear_child(&(d.children[i]));

	close(out_pipe_fds[0]);
	close(in_pipe_fds[1]);

	echld_get_all_codecs(&(d.enc.to_parent), &(d.dec.from_parent), &(d.enc.to_child), &(d.dec.from_child));

	DISP_DBG((2,"Dispatcher Configured pid=%d parent_in=%d parent_out=%d",d.pid,in_pipe_fds[0],d.parent_out));

	preinit_epan(argv0,main);

	DISP_WRITE(dispatcher->parent_out, NULL, 0, ECHLD_HELLO, 0);
	exit(dispatcher_loop());
}