paulo@0: /*
paulo@0:  * $Id: push_proxy.c,v 1.2 2004/06/02 07:13:02 hipnod Exp $
paulo@0:  *
paulo@0:  * Copyright (C) 2004 giFT project (gift.sourceforge.net)
paulo@0:  *
paulo@0:  * This program is free software; you can redistribute it and/or modify it
paulo@0:  * under the terms of the GNU General Public License as published by the
paulo@0:  * Free Software Foundation; either version 2, or (at your option) any
paulo@0:  * later version.
paulo@0:  *
paulo@0:  * This program is distributed in the hope that it will be useful, but
paulo@0:  * WITHOUT ANY WARRANTY; without even the implied warranty of
paulo@0:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
paulo@0:  * General Public License for more details.
paulo@0:  */
paulo@0: 
paulo@0: #include "gt_gnutella.h"
paulo@0: 
paulo@0: #include "gt_node.h"
paulo@0: #include "gt_packet.h"     /* htovs() */
paulo@0: 
paulo@0: #include "transfer/push_proxy.h"
paulo@0: 
paulo@0: /*****************************************************************************/
paulo@0: 
paulo@0: /*
paulo@0:  * All this GGEP stuff will move somewhere else soon.  Just haven't decided
paulo@0:  * where to put it.
paulo@0:  */
paulo@0: 
paulo@0: /*****************************************************************************/
paulo@0: 
paulo@0: #define PROXY_DEBUG          gt_config_get_int("push_proxy/debug=0")
paulo@0: 
paulo@0: /*****************************************************************************/
paulo@0: 
paulo@0: #define GGEP_HDR_LEN         (1)    /* 0xc3 */
paulo@0: #define GGEP_EXT_MAX_LEN     (63)   /* use only a single len chunk for now */
paulo@0: 
paulo@0: enum ggep_length_flags
paulo@0: {
paulo@0: 	GGEP_LEN_NOT_LAST      = 0x80,  /* not the last chunk */
paulo@0: 	GGEP_LEN_LAST          = 0x40,  /* last length chunk flag */
paulo@0: };
paulo@0: 
paulo@0: enum ggep_extension_flags
paulo@0: {
paulo@0: 	GGEP_EXTF_LAST         = 0x80,  /* last extension */
paulo@0: 	GGEP_EXTF_COBS_ENCODED = 0x40,  /* encoded with COBS-encoding */
paulo@0: 	GGEP_EXTF_COMPRESSED   = 0x20,  /* compressed */
paulo@0: 	GGEP_EXTF_RESERVED     = 0x10,  /* reserved */
paulo@0: 
paulo@0: 	/* lower 4 bits is identifier length */
paulo@0: };
paulo@0: 
paulo@0: /*****************************************************************************/
paulo@0: 
paulo@0: struct proxy_addr
paulo@0: {
paulo@0: 	in_addr_t  ipv4;
paulo@0: 	in_port_t  port;
paulo@0: };
paulo@0: 
paulo@0: typedef struct ggep
paulo@0: {
paulo@0: 	uint8_t   *block;
paulo@0: 	size_t     block_len;
paulo@0: 	size_t     offset;
paulo@0: 	size_t     last_ext_offset;
paulo@0: 	BOOL       error;
paulo@0: } ggep_t;
paulo@0: 
paulo@0: /*****************************************************************************/
paulo@0: 
paulo@0: static ggep_t     proxy_block;
paulo@0: static Dataset   *proxies;
paulo@0: 
paulo@0: /*****************************************************************************/
paulo@0: 
paulo@0: static BOOL ggep_grow (ggep_t *ggep, size_t sz)
paulo@0: {
paulo@0: 	uint8_t *new_block;
paulo@0: 	size_t   new_size;
paulo@0: 
paulo@0: 	new_size = ggep->block_len + sz;
paulo@0: 	if (!(new_block = realloc (ggep->block, new_size)))
paulo@0: 		return FALSE;
paulo@0: 
paulo@0: 	ggep->block     = new_block;
paulo@0: 	ggep->block_len = new_size;
paulo@0: 
paulo@0: 	return TRUE;
paulo@0: }
paulo@0: 
paulo@0: static BOOL ggep_init (ggep_t *ggep)
paulo@0: {
paulo@0: 	ggep->block_len       = 1;
paulo@0: 	ggep->offset          = 1;
paulo@0: 	ggep->last_ext_offset = 0;
paulo@0: 	ggep->error           = FALSE;
paulo@0: 
paulo@0: 	if (!(ggep->block = malloc (1)))
paulo@0: 		return FALSE;
paulo@0: 
paulo@0: 	/* append magic byte */
paulo@0: 	ggep->block[0] = 0xc3;
paulo@0: 
paulo@0: 	return TRUE;
paulo@0: }
paulo@0: 
paulo@0: static void ggep_append (ggep_t *ggep, const void *data, size_t data_size)
paulo@0: {
paulo@0: 	if (ggep_grow (ggep, data_size) == FALSE)
paulo@0: 	{
paulo@0: 		ggep->error = TRUE;
paulo@0: 		return;
paulo@0: 	}
paulo@0: 
paulo@0: 	assert (ggep->offset + data_size <= ggep->block_len);
paulo@0: 	memcpy (&ggep->block[ggep->offset], data, data_size);
paulo@0: 	ggep->offset += data_size;
paulo@0: }
paulo@0: 
paulo@0: /* TODO: this should use a writev()-like interface */
paulo@0: static BOOL ggep_append_extension (ggep_t *ggep, const char *id,
paulo@0:                                    const uint8_t *data, size_t data_len)
paulo@0: {
paulo@0: 	uint8_t id_len;
paulo@0: 	uint8_t ext_flags;
paulo@0: 	uint8_t ext_data_len;
paulo@0: 
paulo@0: 	id_len = strlen (id) & 0x0f;
paulo@0: 
paulo@0: 	/* disable Encoding, Compression, LastExtension bits, len in low 4 bits */
paulo@0: 	ext_flags = id_len;
paulo@0: 
paulo@0: 	/* track position of last extension for setting LastExtension bit */
paulo@0: 	ggep->last_ext_offset = ggep->offset;
paulo@0: 
paulo@0: 	/* extension flag header */
paulo@0: 	ggep_append (ggep, &ext_flags, 1);
paulo@0: 
paulo@0: 	/* extension identifier */
paulo@0: 	ggep_append (ggep, id, id_len);
paulo@0: 
paulo@0: 	assert (data_len <= GGEP_EXT_MAX_LEN);
paulo@0: 	ext_data_len = data_len | GGEP_LEN_LAST; /* add last length chunk flag */
paulo@0: 
paulo@0: 	/* the extension length */
paulo@0: 	ggep_append (ggep, &ext_data_len, 1);
paulo@0: 
paulo@0: 	/* the extension data */
paulo@0: 	ggep_append (ggep, data, data_len);
paulo@0: 
paulo@0: 	if (ggep->error)
paulo@0: 		return FALSE;
paulo@0: 
paulo@0: 	return TRUE;
paulo@0: }
paulo@0: 
paulo@0: static BOOL ggep_seal (ggep_t *ggep)
paulo@0: {
paulo@0: 	if (ggep->last_ext_offset == 0)
paulo@0: 		return FALSE;
paulo@0: 
paulo@0: 	/* set the LastExtension bit on the last extension */
paulo@0: 	ggep->block[ggep->last_ext_offset] |= GGEP_EXTF_LAST;
paulo@0: 	return TRUE;
paulo@0: }
paulo@0: 
paulo@0: static void ggep_finish (ggep_t *ggep)
paulo@0: {
paulo@0: 	free (ggep->block);
paulo@0: }
paulo@0: 
paulo@0: /*****************************************************************************/
paulo@0: 
paulo@0: static void ds_add_proxy (ds_data_t *key, ds_data_t *value, void **cmp)
paulo@0: {
paulo@0: 	uint8_t           *push_ext     = cmp[0];
paulo@0: 	size_t            *push_ext_len = cmp[1];
paulo@0: 	in_port_t          port;
paulo@0: 	struct proxy_addr *proxy = value->data;
paulo@0: 
paulo@0: 	port = htovs (proxy->port);
paulo@0: 
paulo@0: 	if (*push_ext_len + 6 >= GGEP_EXT_MAX_LEN)
paulo@0: 		return;
paulo@0: 
paulo@0: 	/* build the PUSH extension */
paulo@0: 	memcpy (&push_ext[*push_ext_len], &proxy->ipv4, 4); *push_ext_len += 4;
paulo@0: 	memcpy (&push_ext[*push_ext_len], &port, 2);        *push_ext_len += 2;
paulo@0: }
paulo@0: 
paulo@0: static void update_block (ggep_t *ggep)
paulo@0: {
paulo@0: 	uint8_t push_ext[GGEP_EXT_MAX_LEN]; /* ugh */
paulo@0: 	size_t  push_ext_len;               /* double ugh */
paulo@0: 	void   *cmp[2];
paulo@0: 
paulo@0: 	ggep_finish (ggep);
paulo@0: 
paulo@0: 	if (ggep_init (ggep) == FALSE)
paulo@0: 		return;
paulo@0: 
paulo@0: 	cmp[0] = push_ext;
paulo@0: 	cmp[1] = &push_ext_len;
paulo@0: 
paulo@0: 	push_ext_len = 0;
paulo@0: 	dataset_foreach (proxies, DS_FOREACH(ds_add_proxy), cmp);
paulo@0: 	assert (push_ext_len <= GGEP_EXT_MAX_LEN);
paulo@0: 
paulo@0: 	if (ggep_append_extension (ggep, "PUSH", push_ext, push_ext_len) == FALSE)
paulo@0: 		return;
paulo@0: 
paulo@0: 	ggep_seal (ggep);
paulo@0: }
paulo@0: 
paulo@0: /*****************************************************************************/
paulo@0: 
paulo@0: static void push_proxy_change (GtNode *node, in_addr_t ipv4,
paulo@0:                                in_port_t port, BOOL add)
paulo@0: {
paulo@0: 	struct proxy_addr  addr;
paulo@0: 	struct proxy_addr *stored;
paulo@0: 
paulo@0: 	addr.ipv4 = ipv4;
paulo@0: 	addr.port = port;
paulo@0: 
paulo@0: 	stored = dataset_lookup (proxies, &node, sizeof(node));
paulo@0: 	if (PROXY_DEBUG)
paulo@0: 	{
paulo@0: 		if (add && !stored)
paulo@0: 			GT->DBGFN (GT, "adding push proxy %s:%hu", net_ip_str (ipv4), port);
paulo@0: 		else if (!add && stored)
paulo@0: 			GT->DBGFN (GT, "rming push proxy %s:%hu", net_ip_str (ipv4), port);
paulo@0: 	}
paulo@0: 
paulo@0: 	if (add)
paulo@0: 		dataset_insert (&proxies, &node, sizeof(node), &addr, sizeof(addr));
paulo@0: 	else
paulo@0: 		dataset_remove (proxies, &node, sizeof(node));
paulo@0: 
paulo@0: 	update_block (&proxy_block);
paulo@0: }
paulo@0: 
paulo@0: void gt_push_proxy_add (GtNode *node, in_addr_t ipv4, in_port_t port)
paulo@0: {
paulo@0: 	assert (node->push_proxy_ip == 0);
paulo@0: 	assert (node->push_proxy_port == 0);
paulo@0: 
paulo@0: 	push_proxy_change (node, ipv4, port, TRUE);
paulo@0: 	node->push_proxy_ip   = ipv4;
paulo@0: 	node->push_proxy_port = port;
paulo@0: }
paulo@0: 
paulo@0: /*
paulo@0:  * This must be called if the port changes, or if the proxy disconnects.
paulo@0:  */
paulo@0: void gt_push_proxy_del (GtNode *node)
paulo@0: {
paulo@0: 	push_proxy_change (node, node->push_proxy_ip,
paulo@0: 	                   node->push_proxy_port, FALSE);
paulo@0: 	node->push_proxy_ip   = 0;
paulo@0: 	node->push_proxy_port = 0;
paulo@0: }
paulo@0: 
paulo@0: BOOL gt_push_proxy_get_ggep_block (uint8_t **block, size_t *block_len)
paulo@0: {
paulo@0: 	if (dataset_length (proxies) == 0)
paulo@0: 		return FALSE;
paulo@0: 
paulo@0: 	*block     = proxy_block.block;
paulo@0: 	*block_len = proxy_block.block_len;
paulo@0: 
paulo@0: 	return TRUE;
paulo@0: }
paulo@0: 
paulo@0: /*****************************************************************************/
paulo@0: 
paulo@0: void gt_push_proxy_init (void)
paulo@0: {
paulo@0: 	ggep_init (&proxy_block);
paulo@0: }
paulo@0: 
paulo@0: void gt_push_proxy_cleanup (void)
paulo@0: {
paulo@0: 	dataset_clear (proxies);
paulo@0: 	proxies = NULL;
paulo@0: 
paulo@0: 	ggep_finish (&proxy_block);
paulo@0: }