1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/io/rx_stack.c	Sat Feb 20 21:18:28 2010 -0800
     1.3 @@ -0,0 +1,318 @@
     1.4 +/*
     1.5 + * $Id: rx_stack.c,v 1.8 2004/02/01 08:17:12 hipnod Exp $
     1.6 + *
     1.7 + * Copyright (C) 2003 giFT project (gift.sourceforge.net)
     1.8 + *
     1.9 + * This program is free software; you can redistribute it and/or modify it
    1.10 + * under the terms of the GNU General Public License as published by the
    1.11 + * Free Software Foundation; either version 2, or (at your option) any
    1.12 + * later version.
    1.13 + *
    1.14 + * This program is distributed in the hope that it will be useful, but
    1.15 + * WITHOUT ANY WARRANTY; without even the implied warranty of
    1.16 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    1.17 + * General Public License for more details.
    1.18 + */
    1.19 +
    1.20 +#include "gt_gnutella.h"
    1.21 +#include "gt_node.h"
    1.22 +
    1.23 +#include "rx_stack.h"
    1.24 +#include "rx_layer.h"
    1.25 +#include "rx_link.h"
    1.26 +#include "rx_inflate.h"
    1.27 +#include "rx_packet.h"
    1.28 +
    1.29 +/*****************************************************************************/
    1.30 +
    1.31 +struct gt_rx_stack
    1.32 +{
    1.33 +	TCPC                  *c;
    1.34 +	BOOL                   inflated;
    1.35 +
    1.36 +	int                    depth;        /* how deep in the stack we have
    1.37 +	                                        currently called into the stack */
    1.38 +	BOOL                   aborted;      /* one of our layers bailed out */
    1.39 +	BOOL                   free_delayed; /* somebody called free during
    1.40 +	                                        message emission, and we delayed 
    1.41 +	                                        it for later */
    1.42 +	void                  *udata;
    1.43 +	struct rx_layer       *layers;
    1.44 +
    1.45 +	GtRxStackHandler       handler;
    1.46 +	GtRxStackCleanup       cleanup;
    1.47 +};
    1.48 +
    1.49 +static struct use_layer
    1.50 +{
    1.51 +	const char           *name;
    1.52 +	struct rx_layer_ops  *ops;
    1.53 +} layers[] =
    1.54 +{
    1.55 +	{ "rx_link",    &gt_rx_link_ops    },
    1.56 +	{ "rx_inflate", &gt_rx_inflate_ops },
    1.57 +	{ "rx_packet",  &gt_rx_packet_ops  },
    1.58 +};
    1.59 +
    1.60 +/*****************************************************************************/
    1.61 +
    1.62 +static void foreach_child (struct rx_layer *rx,
    1.63 +                           void (*exec)(struct rx_layer *rx, void *udata),
    1.64 +                           void *udata)
    1.65 +{
    1.66 +	struct rx_layer *next;
    1.67 +
    1.68 +	while (rx != NULL)
    1.69 +	{
    1.70 +		/* grab the next element first so the callback can call free */
    1.71 +		next = rx->lower;
    1.72 +
    1.73 +		exec (rx, udata);
    1.74 +
    1.75 +		rx = next;
    1.76 +	}
    1.77 +}
    1.78 +
    1.79 +static void disable_layer (struct rx_layer *rx, void *udata)
    1.80 +{
    1.81 +	gt_rx_layer_disable (rx);
    1.82 +}
    1.83 +
    1.84 +static void destroy_foreach (struct rx_layer *rx, void *udata)
    1.85 +{
    1.86 +	gt_rx_layer_free (rx);
    1.87 +}
    1.88 +
    1.89 +static void disable_all (GtRxStack *stack)
    1.90 +{
    1.91 +	struct rx_layer *layers = stack->layers;
    1.92 +
    1.93 +	/* we must be at the top layer already */
    1.94 +	assert (layers->upper == NULL);
    1.95 +
    1.96 +	foreach_child (layers, disable_layer, NULL);
    1.97 +}
    1.98 +
    1.99 +/*****************************************************************************/
   1.100 +
   1.101 +static struct rx_layer *push_layer (struct rx_layer *below,
   1.102 +                                    struct rx_layer *above)
   1.103 +{
   1.104 +	if (above)
   1.105 +		above->lower = below;
   1.106 +
   1.107 +	if (below)
   1.108 +		below->upper = above;
   1.109 +
   1.110 +	return above;
   1.111 +}
   1.112 +
   1.113 +static void free_all_layers (GtRxStack *stack)
   1.114 +{
   1.115 +	struct rx_layer *layers;
   1.116 +
   1.117 +	if (!stack)
   1.118 +		return;
   1.119 +
   1.120 +	layers = stack->layers;
   1.121 +
   1.122 +	if (!layers)
   1.123 +		return;
   1.124 +
   1.125 +	/* make sure we've stopped all processing on this layer */
   1.126 +	disable_all (stack);
   1.127 +
   1.128 +	/* call each layer's destroy method */
   1.129 +	foreach_child (layers, destroy_foreach, NULL);
   1.130 +}
   1.131 +
   1.132 +static struct rx_layer *alloc_layers (GtRxStack *stack, TCPC *c,
   1.133 +                                      BOOL rx_inflated)
   1.134 +{
   1.135 +	struct rx_layer  *layer     = NULL;
   1.136 +	struct rx_layer  *new_layer = NULL;
   1.137 +	void             *udata     = NULL;
   1.138 +	int               i;
   1.139 +
   1.140 +	for (i = 0; i < sizeof(layers) / sizeof(layers[0]); i++)
   1.141 +	{
   1.142 +		/* XXX */
   1.143 +		if (!strcmp (layers[i].name, "rx_link"))
   1.144 +			udata = c;
   1.145 +
   1.146 +		if (!strcmp (layers[i].name, "rx_inflate") && !rx_inflated)
   1.147 +			continue;
   1.148 +
   1.149 +		if (!(new_layer = gt_rx_layer_new (stack, layers[i].name,
   1.150 +		                                layers[i].ops, udata)))
   1.151 +		{
   1.152 +			foreach_child (layer, destroy_foreach, NULL);
   1.153 +			return NULL;
   1.154 +		}
   1.155 +
   1.156 +		layer = push_layer (layer, new_layer);
   1.157 +		udata = NULL;
   1.158 +	}
   1.159 +
   1.160 +	return layer;
   1.161 +}
   1.162 +
   1.163 +/*****************************************************************************/
   1.164 +
   1.165 +static void enable_layer (struct rx_layer *rx, void *udata)
   1.166 +{
   1.167 +	gt_rx_layer_enable (rx);
   1.168 +}
   1.169 +
   1.170 +GtRxStack *gt_rx_stack_new (GtNode *node, TCPC *c, BOOL rx_inflated)
   1.171 +{
   1.172 +	GtRxStack *stack;
   1.173 +	int        size;
   1.174 +
   1.175 +	if (!(stack = NEW (GtRxStack)))
   1.176 +		return NULL;
   1.177 +
   1.178 +	stack->c        = c;
   1.179 +	stack->inflated = rx_inflated;
   1.180 +
   1.181 +	if (!(stack->layers = alloc_layers (stack, c, rx_inflated)))
   1.182 +	{
   1.183 +		free (stack);
   1.184 +		return NULL;
   1.185 +	}
   1.186 +
   1.187 +	/* set the receive buf to a not large value */
   1.188 +	size = 4096;
   1.189 +
   1.190 +	if (setsockopt (c->fd, SOL_SOCKET, SO_RCVBUF, &size, sizeof (size)) != 0)
   1.191 +		GT->DBGSOCK (GT, c, "Error setting rcvbuf size: %s", GIFT_NETERROR());
   1.192 +
   1.193 +	/* enable each layer */
   1.194 +	foreach_child (stack->layers, enable_layer, NULL);
   1.195 +
   1.196 +	return stack;
   1.197 +}
   1.198 +
   1.199 +/*****************************************************************************/
   1.200 +
   1.201 +/* 
   1.202 + * Cleanup handling. This is a bit tricky, because both the owner of the
   1.203 + * stack and the stack itself may want to free the stack, and they both have
   1.204 + * to coordinate so only one of them does the free(). 
   1.205 + * 
   1.206 + * Also, the stack has to worry about the free happening whilst a message
   1.207 + * emission is taking place, and so has to unwind the stack to the top level
   1.208 + * to make sure it doesn't reference freed memory.
   1.209 + */
   1.210 +
   1.211 +static void free_stack (GtRxStack *stack)
   1.212 +{
   1.213 +	/*
   1.214 +	 * ->cleanup gets called from the lower layers, and only
   1.215 +	 * if something bad happened (socket close, etc).
   1.216 +	 */
   1.217 +	free_all_layers (stack);
   1.218 +	FREE (stack);
   1.219 +}
   1.220 +
   1.221 +void gt_rx_stack_free (GtRxStack *stack)
   1.222 +{
   1.223 +	if (!stack)
   1.224 +		return;
   1.225 +
   1.226 +	/*
   1.227 +	 * If we in the middle of a reception when someone calls this function
   1.228 +	 * [say by calling gt_node_disconenct()], we can't free right now
   1.229 +	 * because the data structures are still in use in the reception stack.
   1.230 +	 *
   1.231 +	 * So we queue the removal in that case, by setting free_delayed and
   1.232 +	 * freeing when the stack unwinds, just like when waiting to notify the
   1.233 +	 * stack's listener about gt_rx_stack_abort().
   1.234 +	 */
   1.235 +	if (stack->depth > 0)
   1.236 +	{
   1.237 +		/* we'll defer the real free until later */
   1.238 +		stack->free_delayed = TRUE;
   1.239 +
   1.240 +		/* we must stop processing */
   1.241 +		gt_rx_stack_abort (stack);
   1.242 +
   1.243 +		return;
   1.244 +	}
   1.245 +
   1.246 +	free_stack (stack);
   1.247 +}
   1.248 +
   1.249 +/* notify the user of the stack it's time to clean up this stack */
   1.250 +static void cleanup_notify (GtRxStack *stack)
   1.251 +{
   1.252 +	/*
   1.253 +	 * First, we check if our owner tried to call ->free on us already.
   1.254 +	 * If so, we don't notify them because they already are well aware we are
   1.255 +	 * on our way to oblivion.
   1.256 +	 */
   1.257 +	if (stack->free_delayed)
   1.258 +	{
   1.259 +		free_stack (stack);
   1.260 +		return;
   1.261 +	}
   1.262 +
   1.263 +	if (stack->aborted)
   1.264 +		stack->cleanup (stack->udata);
   1.265 +}
   1.266 +
   1.267 +void gt_rx_stack_recv_start (GtRxStack *stack)
   1.268 +{
   1.269 +	assert (stack->depth >= 0);
   1.270 +	stack->depth++;
   1.271 +}
   1.272 +
   1.273 +void gt_rx_stack_recv_end (GtRxStack *stack)
   1.274 +{
   1.275 +	assert (stack->depth > 0);
   1.276 +
   1.277 +	if (--stack->depth == 0)
   1.278 +		cleanup_notify (stack);
   1.279 +}
   1.280 +
   1.281 +/*
   1.282 + * RX layers call this function when something bad happens and they need
   1.283 + * to abort the stack processing.
   1.284 + *
   1.285 + * In other words, this is the "oh shit" function.
   1.286 + */
   1.287 +void gt_rx_stack_abort (GtRxStack *stack)
   1.288 +{
   1.289 +	disable_all (stack);
   1.290 +
   1.291 +	/* set the flag indicated this stack has been aborted while processing */
   1.292 +	stack->aborted = TRUE;
   1.293 +
   1.294 +	/*
   1.295 +	 * If we are in the middle of receiving some data, set stack->aborted
   1.296 +	 * so when the reception unwinds, we'll notify the owner of the
   1.297 +	 * stack's cleanup function.
   1.298 +	 */
   1.299 +	if (stack->depth > 0)
   1.300 +		return;
   1.301 +
   1.302 +	/* 
   1.303 +	 * This can happen from the bottom layer, if it hasn't passed any data to
   1.304 +	 * upper layers yet.  TODO: if the bottom layer was driven by the RX stack
   1.305 +	 * instead of rx_link, this wouldn't need to be here, i think..
   1.306 +	 */
   1.307 +	cleanup_notify (stack);
   1.308 +}
   1.309 +
   1.310 +void gt_rx_stack_set_handler (GtRxStack *stack, GtRxStackHandler handler,
   1.311 +                              GtRxStackCleanup cleanup, void *udata)
   1.312 +{
   1.313 +	stack->udata   = udata;
   1.314 +	stack->handler = handler;
   1.315 +	stack->cleanup = cleanup;
   1.316 +
   1.317 +	/*
   1.318 +	 * The topmost layer is rx_packet, so we can simply set the data.
   1.319 +	 */
   1.320 +	gt_rx_packet_set_handler (stack->layers, handler, udata);
   1.321 +}