/* Copyright (C) 2005, REDSonic, inc. * Author:  Wills Yin <wills_yin@redsonic.com> */#include <stdio.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include "sap.h"#include "sdp.h"#ifdef HAVE_ZLIB_H#   include <zlib.h>#endif#define MAX_SAP_BUFFER          5000#define MCAST_SAP_VERSION_MASK  0xE0 /* 3 bits for  SAP version*/#define MCAST_SAP_VERSION_SHIFT 5    /* Right shift 5 bits to get the version */#define MCAST_SAP_VER0          0    /* Version 0 */#define MCAST_SAP_BIT_A         0x10 /* Address type: 0 IPv4, 1 IPv6 */#define MCAST_SAP_BIT_R         0x08 /* Reserved: Must be 0 */#define MCAST_SAP_BIT_T         0x04 /* Message Type: 0 announcement, 1 deletion */#define MCAST_SAP_BIT_E         0x02 /* Encryption Bit: 1 payload encrypted */#define MCAST_SAP_BIT_C         0x01 /* Compressed Bit: 1 payload zlib compressed */#define IPV4_ADDR_LEN           4#define IPV6_ADDR_LEN           16#ifdef HAVE_ZLIB_Hstatic int Decompress( const unsigned char *src,unsigned char** _dst , int slen);#endifsap_session_t*  sap_parse(char* packet, int packet_len){	int addr_len;	int total, offset, auth_len;	int            decomp_size;	char*          decomp_buffer;	char           *buffer, *p;	sap_session_t* sap;;	if (!packet)		return NULL;	total = packet_len;	buffer = packet;	decomp_size   = -1;	decomp_buffer = NULL;		offset = 0;    	if ((sap = malloc(sizeof(sap_session_t))) == NULL)		return NULL;	bzero(sap, sizeof(sap_session_t));	sap->version = buffer[offset]>>MCAST_SAP_VERSION_SHIFT;	if (sap->version != 1) 		fprintf(stderr, "Strange SAP version %d found\n", sap->version);	sap->addrType = buffer[offset] & MCAST_SAP_BIT_A;	if ( buffer[offset] & MCAST_SAP_BIT_R ) 		fprintf(stderr, "SAP packet reserved bit incorrectly set\n");	sap->isDel       = buffer[offset] & MCAST_SAP_BIT_T;        sap->isEnc       = buffer[offset] & MCAST_SAP_BIT_E;	if ( sap->isEnc ) {		fprintf(stderr, "Encrypted SAP packet, unsupported\n");		goto error_exit;	}        sap->isComp      = buffer[offset] & MCAST_SAP_BIT_C;	offset++;	auth_len = buffer[offset];	offset++;	sap->hashID = (buffer[offset]<< 8) + buffer[offset + 1];	offset += 2;	addr_len     = sap->addrType ? IPV6_ADDR_LEN : IPV4_ADDR_LEN;	//strncpy(&sap->sourceIP[0], &buffer[offset], addr_len);	if (addr_len == IPV4_ADDR_LEN)	    sprintf(sap->sourceIP, "%d.%d.%d.%d", buffer[offset], buffer[offset+1],			            buffer[offset+2], buffer[offset+3]);	else	    strncpy(&sap->sourceIP[0], &buffer[offset], addr_len);	offset += addr_len;	offset += auth_len * sizeof(int32_t);	if (sap->isComp) {#ifdef HAVE_ZLIB_H		decomp_size = Decompress( buffer + offset, &decomp_buffer,total - offset );		if (decomp_size < 0 || decomp_size > MAX_SAP_BUFFER) 			goto error_exit;		buffer = decomp_buffer;		total  = decomp_size;#else		fprintf(stderr, "Ignoring compressed sap packet\n");		goto error_exit;#endif	} else {		buffer += offset;   		total  -= offset;	}	p = buffer;	/* 	 * Skip payload type without \0 between SAP and SDP 	 */	while ( *p != '\0' && (p[0] != 'v' && p[1] != '='))		p++;	if (*p == '\0') p++;	if( p != buffer && strcasecmp( buffer, "application/sdp" ) )		fprintf(stderr, "Unhandled content type: %s\n", buffer);        	sap->sdp = sdp_parse(p, total - (p - buffer));	SAFE_FREE(decomp_buffer);	return sap;error_exit:	SAFE_FREE(sap);	SAFE_FREE(decomp_buffer);	return NULL;}void  sap_destroy(sap_session_t* sap){	if ( !sap ) return;	sdp_destroy(sap->sdp);	free(sap);}#ifdef HAVE_ZLIB_Hstatic int Decompress( const unsigned char *src,unsigned char** _dst, int slen ) {	int result, dstsize, n;	unsigned char *dst;	z_stream       d_stream;	d_stream.zalloc = (alloc_func)0;	d_stream.zfree  = (free_func)0;	d_stream.opaque = (voidpf)0;	result = inflateInit(&d_stream);	if( result != Z_OK ) {		printf( "inflateInit() failed. Result: %d\n", result );		return( -1 );	}	d_stream.next_in  = (Bytef *)src;	d_stream.avail_in = slen;	n   = 0;	dst = NULL;	do {		n++;		dst = (unsigned char *)realloc(dst, n * 1000);		d_stream.next_out  = (Bytef *)&dst[(n - 1) * 1000];		d_stream.avail_out = 1000;		result = inflate(&d_stream, Z_NO_FLUSH);		if( ( result != Z_OK ) && ( result != Z_STREAM_END ) ) {			printf( "Zlib decompression failed. Result: %d\n", result );			return( -1 );		}	}	while( ( d_stream.avail_out == 0 ) && ( d_stream.avail_in != 0 ) && 					( result != Z_STREAM_END ) );	dstsize = d_stream.total_out;	inflateEnd( &d_stream );	*_dst = (unsigned char *)realloc( dst, dstsize );	return dstsize;}#endif