/* $Id: pdu.c,v 1.2 2000/12/26 19:30:23 remlali Exp $ * * Copyright 2000 Larry Liimatainen * pdu.c -- data encapsulation * * 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, Cambridge, MA 02139, USA. * * pdu.c -- low level package transfer * */ /* * All these functions operate on a packet that is * sent between database daemon and the client API. * * * PROTOCOL LAYOUT * * +--------+--------+--------+--------+---------+-----+ * | Action | Length | ObjLen | Object | Members | ... | * +--------+--------+--------+--------+---------+-----+ * <------------- Header -------------><--- PDU -------> * * We are here * * HEADER: * * Action is a 32bit integer telling upper layer what * to do with data in PDU. * * Length is a 32bit integer and has the size of header * length and PDU length. * * ObjLen is the length of Object in header. * * Object is a single piece of data, used to represent * a database table. * * PDU * * The PDU consist of one or more Members. Each * member has following layout: * * +--------------+------------+------------+ * | memberLength | memberType | MemberData | * +--------------+------------+------------+ * * memberLength is the length of the Member. * * memberType tells upper layer how to read * data in MemberData, ie a string, integer.. * * memberData holds actual data, that usually * represent a field in a database row that is * processed. * */ #ifdef HAVE_CONFIG_H #include #endif #include #include #include #include #include "dbapi.h" #include "ddserver.h" /* debug_decode_output() * * use this to get a quick look at your packet, before entering gdb * n is offset * packet is source of output * offset is offset to rewind * len is how much data to output * */ void debug_decode_output(gint *n, unsigned char *packet, gint offset, gint len) { unsigned char c; gint i; fprintf(stderr,"\nERROR_DATADUMP: n is %d, start is n - %d, printing %d bytes\n", *n, offset, len); i = *n; i -= offset; for(;len;len--){ c = *(packet +i); fprintf(stderr,"%x ", c); i++; } fprintf(stderr,"\n"); } /* get_member() * decodes depending on memberType to buffer or integer * * */ gint get_member(gint *n, gpointer packet, gpointer buffer){ gint ml, mt; memcpy(&ml, packet+*n, sizeof(gint)); /*get MemberLen*/ *n += sizeof(gint); if(ml<8){ fprintf(stderr,"MemberLen is invalid\n"); debug_decode_output(n, packet, 20, 40); return -1; } memcpy(&mt, packet+*n, sizeof(gint)); /*get MemberType*/ *n += sizeof(gint); if(ml == 8){ /* we got a empty memberrecord, its OK ( SQL field is NULL or something)*/ switch(mt) { case PDUMEMTYPE_INT: *(gint *)buffer = 0; return PDUMEMTYPE_INT; case PDUMEMTYPE_STR: *(gchar *)buffer = 0; return PDUMEMTYPE_STR; case PDUMEMTYPE_DOUBLE: *(gdouble *)buffer = 0; return PDUMEMTYPE_DOUBLE; } } switch(mt){ case PDUMEMTYPE_INT: memcpy(buffer, packet+*n, sizeof(gint)); *n += sizeof(gint); return PDUMEMTYPE_INT; case PDUMEMTYPE_DOUBLE: memcpy(buffer, packet+*n, sizeof(gdouble)); *n += sizeof(gdouble); return PDUMEMTYPE_DOUBLE; case PDUMEMTYPE_STR: ml -= sizeof(gint) * 2; /*length of memberData is: *memberLen - sizeof(memberLen) - sizeof(memberType)*/ memcpy(buffer, packet+*n, ml); *((gchar *)(buffer+ml)) = 0; //dont sure this works.... *n += ml; /* advance packetpointer with sizeof(memberData) */ return PDUMEMTYPE_STR; default: /*decode error*/ fprintf(stderr,"get_member(): APP_ERR packet decode error, undefined struct member\n"); debug_decode_output(n, packet, 20, 40); return 0; } return 0; } void add_guint (gint *n, gpointer packet, guint data) { gint tmp; tmp = sizeof(guint) * 3; /* MemberLength is set to Len of itself + MemberType + MemberData*/ memcpy(packet+*n, &tmp, sizeof(guint)); /* cpy MemberLength */ *n += sizeof(guint); tmp = PDUMEMTYPE_INT; memcpy(packet+*n, &tmp, sizeof(guint)); /* cpy MemberType */ *n += sizeof(guint); memcpy(packet+*n, &data, sizeof(guint)); /* cpy MemberData */ *n += sizeof(guint); } void add_gdouble (gint *n, gpointer packet, gdouble data) { gint tmp; tmp = sizeof(guint) * 2 + sizeof(gdouble); /* calculate MemberLength */ memcpy(packet+*n, &tmp, sizeof(guint)); /* cpy MemberLength */ *n += sizeof(guint); tmp = PDUMEMTYPE_DOUBLE; memcpy(packet+*n, &tmp, sizeof(guint)); /* cpy MemberType */ *n += sizeof(guint); memcpy(packet+*n, &data, sizeof(gdouble)); /* cpy MemberData */ *n += sizeof(gdouble); } void add_asciiz (gint *n, gpointer packet, gpointer str) { static gchar nullstr[] = ""; gint j, tmp; if(!str) str = &nullstr; else j = strlen ((gchar *)str); tmp = (sizeof (guint) * 2) + j; /*tmp holds length of MemberLen + MemberType + MemberData */ memcpy (packet+*n, &tmp, sizeof (guint)); *n += sizeof (guint); tmp = PDUMEMTYPE_STR; memcpy (packet+*n, &tmp, sizeof (guint)); *n += sizeof (guint); memcpy (packet+*n, str, j); *n += j; } gint set_pdu_header(gpointer packet, gint type, gchar *table_name) { gint tablen; tablen = strlen(table_name); memcpy(packet, &type, sizeof(gint)); /*set action type*/ memcpy(packet+sizeof(gint), &tablen, sizeof(gint)); /*copy table name len*/ memcpy(packet+(sizeof(gint) * 2), table_name, tablen); /*copy table name*/ return (sizeof(gint) * 3)+tablen; /*header length*/ }