/*
   * 	ucon.c
   *

   * Copyright (c) 2004+ Evgeniy Polyakov <zbr@ioremap.net>

   *
   *
   * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
   */
  
  #include <asm/types.h>
  
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <sys/poll.h>
  
  #include <linux/netlink.h>
  #include <linux/rtnetlink.h>
  
  #include <arpa/inet.h>

  #include <stdbool.h>

  #include <stdio.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <string.h>
  #include <errno.h>
  #include <time.h>

  #include <getopt.h>

  
  #include <linux/connector.h>
  
  #define DEBUG
  #define NETLINK_CONNECTOR 	11

  /* Hopefully your userspace connector.h matches this kernel */
  #define CN_TEST_IDX		CN_NETLINK_USERS + 3
  #define CN_TEST_VAL		0x456

  #ifdef DEBUG
  #define ulog(f, a...) fprintf(stdout, f, ##a)
  #else
  #define ulog(f, a...) do {} while (0)
  #endif
  
  static int need_exit;
  static __u32 seq;
  
  static int netlink_send(int s, struct cn_msg *msg)
  {
  	struct nlmsghdr *nlh;
  	unsigned int size;
  	int err;
  	char buf[128];
  	struct cn_msg *m;
  
  	size = NLMSG_SPACE(sizeof(struct cn_msg) + msg->len);
  
  	nlh = (struct nlmsghdr *)buf;
  	nlh->nlmsg_seq = seq++;
  	nlh->nlmsg_pid = getpid();
  	nlh->nlmsg_type = NLMSG_DONE;
  	nlh->nlmsg_len = NLMSG_LENGTH(size - sizeof(*nlh));
  	nlh->nlmsg_flags = 0;
  
  	m = NLMSG_DATA(nlh);
  #if 0
  	ulog("%s: [%08x.%08x] len=%u, seq=%u, ack=%u.
  ",
  	       __func__, msg->id.idx, msg->id.val, msg->len, msg->seq, msg->ack);
  #endif
  	memcpy(m, msg, sizeof(*m) + msg->len);
  
  	err = send(s, nlh, size, 0);
  	if (err == -1)
  		ulog("Failed to send: %s [%d].
  ",
  			strerror(errno), errno);
  
  	return err;
  }

  static void usage(void)
  {
  	printf(
  		"Usage: ucon [options] [output file]
  "
  		"
  "
  		"\t-h\tthis help screen
  "
  		"\t-s\tsend buffers to the test module
  "
  		"
  "
  		"The default behavior of ucon is to subscribe to the test module
  "
  		"and wait for state messages.  Any ones received are dumped to the
  "
  		"specified output file (or stdout).  The test module is assumed to
  "
  		"have an id of {%u.%u}
  "
  		"
  "
  		"If you get no output, then verify the cn_test module id matches
  "
  		"the expected id above.
  "
  		, CN_TEST_IDX, CN_TEST_VAL
  	);
  }

  int main(int argc, char *argv[])
  {
  	int s;
  	char buf[1024];
  	int len;
  	struct nlmsghdr *reply;
  	struct sockaddr_nl l_local;
  	struct cn_msg *data;
  	FILE *out;
  	time_t tm;
  	struct pollfd pfd;

  	bool send_msgs = false;
  
  	while ((s = getopt(argc, argv, "hs")) != -1) {
  		switch (s) {
  		case 's':
  			send_msgs = true;
  			break;
  
  		case 'h':
  			usage();
  			return 0;
  
  		default:
  			/* getopt() outputs an error for us */
  			usage();
  			return 1;
  		}
  	}

  	if (argc != optind) {
  		out = fopen(argv[optind], "a+");

  		if (!out) {
  			ulog("Unable to open %s for writing: %s
  ",
  				argv[1], strerror(errno));
  			out = stdout;
  		}

  	} else
  		out = stdout;

  
  	memset(buf, 0, sizeof(buf));
  
  	s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
  	if (s == -1) {
  		perror("socket");
  		return -1;
  	}
  
  	l_local.nl_family = AF_NETLINK;

  	l_local.nl_groups = -1; /* bitmask of requested groups */

  	l_local.nl_pid = 0;

  	ulog("subscribing to %u.%u
  ", CN_TEST_IDX, CN_TEST_VAL);

  	if (bind(s, (struct sockaddr *)&l_local, sizeof(struct sockaddr_nl)) == -1) {
  		perror("bind");
  		close(s);
  		return -1;
  	}
  
  #if 0
  	{
  		int on = 0x57; /* Additional group number */
  		setsockopt(s, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &on, sizeof(on));
  	}
  #endif

  	if (send_msgs) {

  		int i, j;
  
  		memset(buf, 0, sizeof(buf));
  
  		data = (struct cn_msg *)buf;

  		data->id.idx = CN_TEST_IDX;
  		data->id.val = CN_TEST_VAL;

  		data->seq = seq++;
  		data->ack = 0;
  		data->len = 0;
  
  		for (j=0; j<10; ++j) {
  			for (i=0; i<1000; ++i) {
  				len = netlink_send(s, data);
  			}
  
  			ulog("%d messages have been sent to %08x.%08x.
  ", i, data->id.idx, data->id.val);
  		}
  
  		return 0;
  	}
  
  
  	pfd.fd = s;
  
  	while (!need_exit) {
  		pfd.events = POLLIN;
  		pfd.revents = 0;
  		switch (poll(&pfd, 1, -1)) {
  			case 0:
  				need_exit = 1;
  				break;
  			case -1:
  				if (errno != EINTR) {
  					need_exit = 1;
  					break;
  				}
  				continue;
  		}
  		if (need_exit)
  			break;
  
  		memset(buf, 0, sizeof(buf));
  		len = recv(s, buf, sizeof(buf), 0);
  		if (len == -1) {
  			perror("recv buf");
  			close(s);
  			return -1;
  		}
  		reply = (struct nlmsghdr *)buf;
  
  		switch (reply->nlmsg_type) {
  		case NLMSG_ERROR:
  			fprintf(out, "Error message received.
  ");
  			fflush(out);
  			break;
  		case NLMSG_DONE:
  			data = (struct cn_msg *)NLMSG_DATA(reply);
  
  			time(&tm);
  			fprintf(out, "%.24s : [%x.%x] [%08u.%08u].
  ",
  				ctime(&tm), data->id.idx, data->id.val, data->seq, data->ack);
  			fflush(out);
  			break;
  		default:
  			break;
  		}
  	}
  
  	close(s);
  	return 0;
  }