/*
   * (C) Copyright 2004
   * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   *
   * SPDX-License-Identifier:	GPL-2.0+
   */
  
  #include <common.h>
  #include <command.h>
  #include <stdio_dev.h>
  #include <net.h>
  
  DECLARE_GLOBAL_DATA_PTR;
  
  #ifndef CONFIG_NETCONSOLE_BUFFER_SIZE
  #define CONFIG_NETCONSOLE_BUFFER_SIZE 512
  #endif
  
  static char input_buffer[CONFIG_NETCONSOLE_BUFFER_SIZE];
  static int input_size; /* char count in input buffer */
  static int input_offset; /* offset to valid chars in input buffer */
  static int input_recursion;
  static int output_recursion;
  static int net_timeout;
  static uchar nc_ether[6]; /* server enet address */
  static IPaddr_t nc_ip; /* server ip */
  static short nc_out_port; /* target output port */
  static short nc_in_port; /* source input port */
  static const char *output_packet; /* used by first send udp */
  static int output_packet_len;
  /*
   * Start with a default last protocol.
   * We are only interested in NETCONS or not.
   */
  enum proto_t net_loop_last_protocol = BOOTP;
  
  static void nc_wait_arp_handler(uchar *pkt, unsigned dest,
  				 IPaddr_t sip, unsigned src,
  				 unsigned len)
  {
  	net_set_state(NETLOOP_SUCCESS); /* got arp reply - quit net loop */
  }
  
  static void nc_handler(uchar *pkt, unsigned dest, IPaddr_t sip, unsigned src,
  			unsigned len)
  {
  	if (input_size)
  		net_set_state(NETLOOP_SUCCESS); /* got input - quit net loop */
  }
  
  static void nc_timeout(void)
  {
  	net_set_state(NETLOOP_SUCCESS);
  }
  
  static int is_broadcast(IPaddr_t ip)
  {
  	static IPaddr_t netmask;
  	static IPaddr_t our_ip;
  	static int env_changed_id;
  	int env_id = get_env_id();
  
  	/* update only when the environment has changed */
  	if (env_changed_id != env_id) {
  		netmask = getenv_IPaddr("netmask");
  		our_ip = getenv_IPaddr("ipaddr");
  
  		env_changed_id = env_id;
  	}
  
  	return (ip == ~0 ||				/* 255.255.255.255 */
  	    ((netmask & our_ip) == (netmask & ip) &&	/* on the same net */
  	    (netmask | ip) == ~0));		/* broadcast to our net */
  }
  
  static int refresh_settings_from_env(void)
  {
  	const char *p;
  	static int env_changed_id;
  	int env_id = get_env_id();
  
  	/* update only when the environment has changed */
  	if (env_changed_id != env_id) {
  		if (getenv("ncip")) {
  			nc_ip = getenv_IPaddr("ncip");
  			if (!nc_ip)
  				return -1;	/* ncip is 0.0.0.0 */
  			p = strchr(getenv("ncip"), ':');
  			if (p != NULL) {
  				nc_out_port = simple_strtoul(p + 1, NULL, 10);
  				nc_in_port = nc_out_port;
  			}
  		} else
  			nc_ip = ~0; /* ncip is not set, so broadcast */
  
  		p = getenv("ncoutport");
  		if (p != NULL)
  			nc_out_port = simple_strtoul(p, NULL, 10);
  		p = getenv("ncinport");
  		if (p != NULL)
  			nc_in_port = simple_strtoul(p, NULL, 10);
  
  		if (is_broadcast(nc_ip))
  			/* broadcast MAC address */
  			memset(nc_ether, 0xff, sizeof(nc_ether));
  		else
  			/* force arp request */
  			memset(nc_ether, 0, sizeof(nc_ether));
  	}
  	return 0;
  }
  
  /**
   * Called from NetLoop in net/net.c before each packet
   */
  void NcStart(void)
  {
  	refresh_settings_from_env();
  	if (!output_packet_len || memcmp(nc_ether, NetEtherNullAddr, 6)) {
  		/* going to check for input packet */
  		net_set_udp_handler(nc_handler);
  		NetSetTimeout(net_timeout, nc_timeout);
  	} else {
  		/* send arp request */
  		uchar *pkt;
  		net_set_arp_handler(nc_wait_arp_handler);
  		pkt = (uchar *)NetTxPacket + NetEthHdrSize() + IP_UDP_HDR_SIZE;
  		memcpy(pkt, output_packet, output_packet_len);
  		NetSendUDPPacket(nc_ether, nc_ip, nc_out_port, nc_in_port,
  			output_packet_len);
  	}
  }
  
  int nc_input_packet(uchar *pkt, IPaddr_t src_ip, unsigned dest_port,
  	unsigned src_port, unsigned len)
  {
  	int end, chunk;
  
  	if (dest_port != nc_in_port || !len)
  		return 0; /* not for us */
  
  	if (src_ip != nc_ip && !is_broadcast(nc_ip))
  		return 0; /* not from our client */
  
  	debug_cond(DEBUG_DEV_PKT, "input: \"%*.*s\"
  ", len, len, pkt);
  
  	if (input_size == sizeof(input_buffer))
  		return 1; /* no space */
  	if (len > sizeof(input_buffer) - input_size)
  		len = sizeof(input_buffer) - input_size;
  
  	end = input_offset + input_size;
  	if (end > sizeof(input_buffer))
  		end -= sizeof(input_buffer);
  
  	chunk = len;
  	if (end + len > sizeof(input_buffer)) {
  		chunk = sizeof(input_buffer) - end;
  		memcpy(input_buffer, pkt + chunk, len - chunk);
  	}
  	memcpy(input_buffer + end, pkt, chunk);
  
  	input_size += len;
  
  	return 1;
  }
  
  static void nc_send_packet(const char *buf, int len)
  {
  	struct eth_device *eth;
  	int inited = 0;
  	uchar *pkt;
  	uchar *ether;
  	IPaddr_t ip;
  
  	debug_cond(DEBUG_DEV_PKT, "output: \"%*.*s\"
  ", len, len, buf);
  
  	eth = eth_get_dev();
  	if (eth == NULL)
  		return;
  
  	if (!memcmp(nc_ether, NetEtherNullAddr, 6)) {
  		if (eth->state == ETH_STATE_ACTIVE)
  			return;	/* inside net loop */
  		output_packet = buf;
  		output_packet_len = len;
  		input_recursion = 1;
  		NetLoop(NETCONS); /* wait for arp reply and send packet */
  		input_recursion = 0;
  		output_packet_len = 0;
  		return;
  	}
  
  	if (eth->state != ETH_STATE_ACTIVE) {
  		if (eth_is_on_demand_init()) {
  			if (eth_init(gd->bd) < 0)
  				return;
  			eth_set_last_protocol(NETCONS);
  		} else
  			eth_init_state_only(gd->bd);
  
  		inited = 1;
  	}
  	pkt = (uchar *)NetTxPacket + NetEthHdrSize() + IP_UDP_HDR_SIZE;
  	memcpy(pkt, buf, len);
  	ether = nc_ether;
  	ip = nc_ip;
  	NetSendUDPPacket(ether, ip, nc_out_port, nc_in_port, len);
  
  	if (inited) {
  		if (eth_is_on_demand_init())
  			eth_halt();
  		else
  			eth_halt_state_only();
  	}
  }
  
  static int nc_start(struct stdio_dev *dev)
  {
  	int retval;
  
  	nc_out_port = 6666; /* default port */
  	nc_in_port = nc_out_port;
  
  	retval = refresh_settings_from_env();
  	if (retval != 0)
  		return retval;
  
  	/*
  	 * Initialize the static IP settings and buffer pointers
  	 * incase we call NetSendUDPPacket before NetLoop
  	 */
  	net_init();
  
  	return 0;
  }
  
  static void nc_putc(struct stdio_dev *dev, char c)
  {
  	if (output_recursion)
  		return;
  	output_recursion = 1;
  
  	nc_send_packet(&c, 1);
  
  	output_recursion = 0;
  }
  
  static void nc_puts(struct stdio_dev *dev, const char *s)
  {
  	int len;
  
  	if (output_recursion)
  		return;
  	output_recursion = 1;
  
  	len = strlen(s);
  	while (len) {
  		int send_len = min(len, (int)sizeof(input_buffer));
  		nc_send_packet(s, send_len);
  		len -= send_len;
  		s += send_len;
  	}
  
  	output_recursion = 0;
  }
  
  static int nc_getc(struct stdio_dev *dev)
  {
  	uchar c;
  
  	input_recursion = 1;
  
  	net_timeout = 0;	/* no timeout */
  	while (!input_size)
  		NetLoop(NETCONS);
  
  	input_recursion = 0;
  
  	c = input_buffer[input_offset++];
  
  	if (input_offset >= sizeof(input_buffer))
  		input_offset -= sizeof(input_buffer);
  	input_size--;
  
  	return c;
  }
  
  static int nc_tstc(struct stdio_dev *dev)
  {
  	struct eth_device *eth;
  
  	if (input_recursion)
  		return 0;
  
  	if (input_size)
  		return 1;
  
  	eth = eth_get_dev();
  	if (eth && eth->state == ETH_STATE_ACTIVE)
  		return 0;	/* inside net loop */
  
  	input_recursion = 1;
  
  	net_timeout = 1;
  	NetLoop(NETCONS);	/* kind of poll */
  
  	input_recursion = 0;
  
  	return input_size != 0;
  }
  
  int drv_nc_init(void)
  {
  	struct stdio_dev dev;
  	int rc;
  
  	memset(&dev, 0, sizeof(dev));
  
  	strcpy(dev.name, "nc");
  	dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM;
  	dev.start = nc_start;
  	dev.putc = nc_putc;
  	dev.puts = nc_puts;
  	dev.getc = nc_getc;
  	dev.tstc = nc_tstc;
  
  	rc = stdio_register(&dev);
  
  	return (rc == 0) ? 1 : rc;
  }