u_char *
snmp_msg_Decode(u_char * Packet, int *PacketLenP,
u_char * Community, int *CommLenP,
int *Version, struct snmp_pdu * PDU)
{
u_char *bufp;
u_char type;
bufp = asn_parse_header(Packet, PacketLenP, &type);
if (bufp == NULL) {
snmplib_debug(4, "snmp_msg_Decode:Error decoding SNMP Message Header (Header)!\n");
ASN_PARSE_ERROR(NULL);
}
if (type != (ASN_SEQUENCE | ASN_CONSTRUCTOR)) {
snmplib_debug(4, "snmp_msg_Decode:Error decoding SNMP Message Header (Header)!\n");
ASN_PARSE_ERROR(NULL);
}
bufp = asn_parse_int(bufp, PacketLenP,
&type,
(int *) Version, sizeof(*Version));
if (bufp == NULL) {
snmplib_debug(4, "snmp_msg_Decode:Error decoding SNMP Message Header (Version)!\n");
ASN_PARSE_ERROR(NULL);
}
bufp = asn_parse_string(bufp, PacketLenP, &type, Community, CommLenP);
if (bufp == NULL) {
snmplib_debug(4, "snmp_msg_Decode:Error decoding SNMP Message Header (Community)!\n");
ASN_PARSE_ERROR(NULL);
}
Community[*CommLenP] = '\0';
if ((*Version != SNMP_VERSION_1) &&
(*Version != SNMP_VERSION_2)) {
/* Don't know how to handle this one. */
snmplib_debug(4, "snmp_msg_Decode:Unable to parse Version %u\n", *Version);
snmplib_debug(4, "snmp_msg_Decode:Continuing anyway\n");
}
/* Now that we know the header, decode the PDU */
/* XXXXX -- More than one PDU? */
bufp = snmp_pdu_decode(bufp, PacketLenP, PDU);
if (bufp == NULL)
/* snmp_pdu_decode registered failure */
return (NULL);
bufp = snmp_var_DecodeVarBind(bufp, PacketLenP, &(PDU->variables), *Version);
if (bufp == NULL)
/* snmp_var_DecodeVarBind registered failure */
return (NULL);
return (u_char *) bufp;
}
/* Parse all Vars from the buffer */
u_char *snmp_var_DecodeVarBind(u_char *Buffer, int *BufLen,
struct variable_list **VarP,
int Version)
{
struct variable_list *Var, **VarLastP;
u_char *bufp, *tmp;
u_char VarBindType;
u_char *DataPtr;
int DataLen;
oid TmpBuf[MAX_NAME_LEN];
int AllVarLen = *BufLen;
int ThisVarLen = 0;
VarLastP = VarP;
#ifdef DEBUG_VARS_DECODE
printf("VARS: Decoding buffer of length %d\n", *BufLen);
#endif
/* Now parse the variables */
bufp = asn_parse_header(Buffer, &AllVarLen, &VarBindType);
if (bufp == NULL)
ASN_PARSE_ERROR(NULL);
if (VarBindType != (u_char)(ASN_SEQUENCE | ASN_CONSTRUCTOR)) {
snmp_set_api_error(SNMPERR_PDU_PARSE);
ASN_PARSE_ERROR(NULL);
}
#ifdef DEBUG_VARS_DECODE
printf("VARS: All Variable length %d\n", AllVarLen);
#endif
/* We know how long the variable list is. Parse it. */
while ((int)AllVarLen > 0) {
/* Create a new variable */
Var = snmp_var_new(NULL, MAX_NAME_LEN);
if (Var == NULL)
return(NULL);
/* Parse the header to find out the length of this variable. */
ThisVarLen = AllVarLen;
tmp = asn_parse_header(bufp, &ThisVarLen, &VarBindType);
if (tmp == NULL)
ASN_PARSE_ERROR(NULL);
/* Now that we know the length , figure out how it relates to
* the entire variable list
*/
AllVarLen = AllVarLen - (ThisVarLen + (tmp - bufp));
bufp = tmp;
/* Is it valid? */
if (VarBindType != (u_char)(ASN_SEQUENCE | ASN_CONSTRUCTOR)) {
snmp_set_api_error(SNMPERR_PDU_PARSE);
ASN_PARSE_ERROR(NULL);
}
#ifdef DEBUG_VARS_DECODE
printf("VARS: Header type 0x%x (%d bytes left)\n", VarBindType, ThisVarLen);
#endif
/* Parse the OBJID */
bufp = asn_parse_objid(bufp, &ThisVarLen, &VarBindType,
Var->name, &(Var->name_length));
if (bufp == NULL)
ASN_PARSE_ERROR(NULL);
if (VarBindType != (u_char)(ASN_UNIVERSAL |
ASN_PRIMITIVE |
ASN_OBJECT_ID)) {
snmp_set_api_error(SNMPERR_PDU_PARSE);
ASN_PARSE_ERROR(NULL);
}
#ifdef DEBUG_VARS_DECODE
printf("VARS: Decoded OBJID (%d bytes). (%d bytes left)\n",
Var->name_length, ThisVarLen);
#endif
/* Keep a pointer to this object */
DataPtr = bufp;
DataLen = ThisVarLen;
/* find out type of object */
bufp = asn_parse_header(bufp, &ThisVarLen, &(Var->type));
if (bufp == NULL)
ASN_PARSE_ERROR(NULL);
ThisVarLen = DataLen;
#ifdef DEBUG_VARS_DECODE
printf("VARS: Data type %d\n", Var->type);
#endif
/* Parse the type */
switch((short)Var->type){
case ASN_INTEGER:
Var->val.integer = (int *)malloc(sizeof(int));
if (Var->val.integer == NULL) {
snmp_set_api_error(SNMPERR_OS_ERR);
return(NULL);
}
Var->val_len = sizeof(int);
bufp = asn_parse_int(DataPtr, &ThisVarLen,
&Var->type, (int *)Var->val.integer,
Var->val_len);
#ifdef DEBUG_VARS_DECODE
printf("VARS: Decoded integer '%d' (%d bytes left)\n",
*(Var->val.integer), ThisVarLen);
#endif
break;
case SMI_COUNTER32:
case SMI_GAUGE32:
/* case SMI_UNSIGNED32: */
case SMI_TIMETICKS:
Var->val.integer = (int *)malloc(sizeof(u_int));
if (Var->val.integer == NULL) {
snmp_set_api_error(SNMPERR_OS_ERR);
return(NULL);
}
Var->val_len = sizeof(u_int);
bufp = asn_parse_unsigned_int(DataPtr, &ThisVarLen,
&Var->type, (u_int *)Var->val.integer,
Var->val_len);
#ifdef DEBUG_VARS_DECODE
printf("VARS: Decoded timeticks '%d' (%d bytes left)\n",
*(Var->val.integer), ThisVarLen);
#endif
break;
case ASN_OCTET_STR:
case SMI_IPADDRESS:
case SMI_OPAQUE:
Var->val_len = *&ThisVarLen; /* String is this at most */
Var->val.string = (u_char *)malloc((unsigned)Var->val_len);
if (Var->val.string == NULL) {
snmp_set_api_error(SNMPERR_OS_ERR);
return(NULL);
}
bufp = asn_parse_string(DataPtr, &ThisVarLen,
&Var->type, Var->val.string,
&Var->val_len);
#ifdef DEBUG_VARS_DECODE
printf("VARS: Decoded string '%s' (length %d) (%d bytes left)\n",
(Var->val.string), Var->val_len, ThisVarLen);
#endif
break;
case ASN_OBJECT_ID:
Var->val_len = MAX_NAME_LEN;
bufp = asn_parse_objid(DataPtr, &ThisVarLen,
&Var->type, TmpBuf, &Var->val_len);
Var->val_len *= sizeof(oid);
Var->val.objid = (oid *)malloc((unsigned)Var->val_len);
if (Var->val.integer == NULL) {
snmp_set_api_error(SNMPERR_OS_ERR);
return(NULL);
}
/* Only copy if we successfully decoded something */
if (bufp) {
memcpy((char *)Var->val.objid, (char *)TmpBuf, Var->val_len);
}
#ifdef DEBUG_VARS_DECODE
printf("VARS: Decoded OBJID (length %d) (%d bytes left)\n",
Var->val_len, ThisVarLen);
#endif
break;
case ASN_NULL:
case SMI_NOSUCHINSTANCE:
case SMI_NOSUCHOBJECT:
case SMI_ENDOFMIBVIEW:
Var->val_len = 0;
Var->val.objid = NULL;
bufp = asn_parse_null(DataPtr, &ThisVarLen, &Var->type);
#ifdef DEBUG_VARS_DECODE
printf("VARS: Decoded ASN_NULL (length %d) (%d bytes left)\n",
Var->val_len, ThisVarLen);
#endif
break;
case SMI_COUNTER64:
#ifdef STDERR_OUTPUT
fprintf(stderr, WIDE("Unable to parse type SMI_COUNTER64!\n"));
#endif
snmp_set_api_error(SNMPERR_UNSUPPORTED_TYPE);
return(NULL);
break;
default:
#ifdef STDERR_OUTPUT
fprintf(stderr, WIDE("bad type returned (%x)\n"), Var->type);
#endif
snmp_set_api_error(SNMPERR_PDU_PARSE);
return(NULL);
break;
} /* End of var type switch */
/* Why is this here? XXXXX */
if (bufp == NULL)
return(NULL);
#ifdef DEBUG_VARS_DECODE
printf("VARS: Adding to list of decoded variables. (%d bytes remain.)\n", AllVarLen);
#endif
/* Add variable to the list */
*VarLastP = Var;
VarLastP = &(Var->next_variable);
}
return(bufp);
}
/* Decodes PDU from Packet into PDU.
*
* Returns a pointer to the next byte of the packet, which is where the
* Variable Bindings start.
*/
u_char *snmp_pdu_decode(u_char *Packet, /* data */
int *Length, /* &length */
struct snmp_pdu *PDU) /* pdu */
{
u_char *bufp;
u_char PDUType;
int four;
u_char ASNType;
oid objid[MAX_NAME_LEN];
bufp = asn_parse_header(Packet, Length, &PDUType);
if (bufp == NULL)
ASN_PARSE_ERROR(NULL);
#ifdef DEBUG_PDU_DECODE
printf("PDU Type: %d\n", PDUType);
#endif
PDU->command = PDUType;
switch (PDUType) {
case TRP_REQ_MSG:
/* SNMPv1 Trap Message */
/* enterprise */
PDU->enterprise_length = MAX_NAME_LEN;
bufp = asn_parse_objid(bufp, Length,
&ASNType, objid, &PDU->enterprise_length);
if (bufp == NULL)
ASN_PARSE_ERROR(NULL);
PDU->enterprise = (oid *)malloc(PDU->enterprise_length * sizeof(oid));
if (PDU->enterprise == NULL) {
snmp_set_api_error(SNMPERR_OS_ERR);
return(NULL);
}
memcpy((char *)PDU->enterprise, (char *)objid,
PDU->enterprise_length * sizeof(oid));
/* Agent-addr */
four = 4;
bufp = asn_parse_string(bufp, Length,
&ASNType,
(u_char *)&PDU->agent_addr.sin_addr.s_addr,
&four);
if (bufp == NULL)
ASN_PARSE_ERROR(NULL);
/* Generic trap */
bufp = asn_parse_int(bufp, Length,
&ASNType,
(int *)&PDU->trap_type,
sizeof(PDU->trap_type));
if (bufp == NULL)
ASN_PARSE_ERROR(NULL);
/* Specific Trap */
bufp = asn_parse_int(bufp, Length,
&ASNType,
(int *)&PDU->specific_type,
sizeof(PDU->specific_type));
if (bufp == NULL)
ASN_PARSE_ERROR(NULL);
/* Timestamp */
bufp = asn_parse_unsigned_int(bufp, Length,
&ASNType,
&PDU->time, sizeof(PDU->time));
if (bufp == NULL)
ASN_PARSE_ERROR(NULL);
break;
/**********************************************************************/
case SNMP_PDU_GETBULK:
/* SNMPv2 Bulk Request */
/* request id */
bufp = asn_parse_int(bufp, Length,
&ASNType,
&PDU->reqid, sizeof(PDU->reqid));
if (bufp == NULL)
ASN_PARSE_ERROR(NULL);
/* non-repeaters */
bufp = asn_parse_int(bufp, Length,
&ASNType,
&PDU->non_repeaters, sizeof(PDU->non_repeaters));
if (bufp == NULL)
ASN_PARSE_ERROR(NULL);
/* max-repetitions */
bufp = asn_parse_int(bufp, Length,
&ASNType,
&PDU->max_repetitions, sizeof(PDU->max_repetitions));
if (bufp == NULL)
ASN_PARSE_ERROR(NULL);
break;
/**********************************************************************/
default:
/* Normal PDU Encoding */
/* request id */
bufp = asn_parse_int(bufp, Length,
&ASNType,
&PDU->reqid, sizeof(PDU->reqid));
if (bufp == NULL)
ASN_PARSE_ERROR(NULL);
#ifdef DEBUG_PDU_DECODE
printf("PDU Request ID: %d\n", PDU->reqid);
#endif
/* error status */
bufp = asn_parse_int(bufp, Length,
&ASNType,
&PDU->errstat, sizeof(PDU->errstat));
if (bufp == NULL)
ASN_PARSE_ERROR(NULL);
#ifdef DEBUG_PDU_DECODE
printf("PDU Error Status: %d\n", PDU->errstat);
#endif
/* error index */
bufp = asn_parse_int(bufp, Length,
&ASNType,
&PDU->errindex, sizeof(PDU->errindex));
if (bufp == NULL)
ASN_PARSE_ERROR(NULL);
#ifdef DEBUG_PDU_DECODE
printf("PDU Error Index: %d\n", PDU->errindex);
#endif
break;
}
return(bufp);
}
