freebsd-dev/usr.sbin/atm/scspd/scsp_input.c
Alfred Perlstein 9e9715e9c0 de-__P()
2002-10-10 00:32:55 +00:00

1089 lines
20 KiB
C

/*
*
* ===================================
* HARP | Host ATM Research Platform
* ===================================
*
*
* This Host ATM Research Platform ("HARP") file (the "Software") is
* made available by Network Computing Services, Inc. ("NetworkCS")
* "AS IS". NetworkCS does not provide maintenance, improvements or
* support of any kind.
*
* NETWORKCS MAKES NO WARRANTIES OR REPRESENTATIONS, EXPRESS OR IMPLIED,
* INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE, AS TO ANY ELEMENT OF THE
* SOFTWARE OR ANY SUPPORT PROVIDED IN CONNECTION WITH THIS SOFTWARE.
* In no event shall NetworkCS be responsible for any damages, including
* but not limited to consequential damages, arising from or relating to
* any use of the Software or related support.
*
* Copyright 1994-1998 Network Computing Services, Inc.
*
* Copies of this Software may be made, however, the above copyright
* notice must be reproduced on all copies.
*
* @(#) $FreeBSD$
*
*/
/*
* Server Cache Synchronization Protocol (SCSP) Support
* ----------------------------------------------------
*
* Input packet processing
*
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netatm/port.h>
#include <netatm/queue.h>
#include <netatm/atm.h>
#include <netatm/atm_if.h>
#include <netatm/atm_sap.h>
#include <netatm/atm_sys.h>
#include <netatm/atm_ioctl.h>
#include <errno.h>
#include <libatm.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include "scsp_msg.h"
#include "scsp_if.h"
#include "scsp_var.h"
#ifndef lint
__RCSID("@(#) $FreeBSD$");
#endif
static int scsp_parse_atmarp(char *, int, Scsp_atmarp_csa **);
/*
* Get a long ingeter
*
* This routine is provided to handle long integers that may not
* be word-aligned in the input buffer.
*
* Arguments:
* cp pointer to long int in message
*
* Returns:
* int long int in host order
*
*/
static u_long
get_long(cp)
u_char *cp;
{
int i;
u_long l;
/*
* Read the long out of the input buffer
*/
l = 0;
for (i = 0; i < sizeof(u_long); i++)
l = (l << 8) + *cp++;
/*
* Return the value in host order
*/
return(l);
}
/*
* Free an SCSP Cache Alignment message in internal format
*
* Arguments:
* cap pointer to CA message
*
* Returns:
* None
*
*/
static void
scsp_free_ca(cap)
Scsp_ca *cap;
{
Scsp_csa *csap, *ncsap;
/*
* Return if there's nothing to free
*/
if (cap == (Scsp_ca *)0)
return;
/*
* Free the CSAS records
*/
for (csap = cap->ca_csa_rec; csap; csap = ncsap) {
ncsap = csap->next;
SCSP_FREE_CSA(csap);
}
/*
* Free the CA message structure
*/
free(cap);
}
/*
* Free an SCSP Cache State Update Request, Cache State Update Reply,
* or Cache State Update Solicit message in internal format
*
* Arguments:
* csup pointer to CSU message
*
* Returns:
* None
*
*/
static void
scsp_free_csu(csup)
Scsp_csu_msg *csup;
{
Scsp_csa *csap, *ncsap;
/*
* Return if there's nothing to free
*/
if (csup == (Scsp_csu_msg *)0)
return;
/*
* Free the CSA records
*/
for (csap = csup->csu_csa_rec; csap; csap = ncsap) {
ncsap = csap->next;
SCSP_FREE_CSA(csap);
}
/*
* Free the CSU message structure
*/
free(csup);
}
/*
* Free an SCSP Hello message in internal format
*
* Arguments:
* hp pointer to Hello message
*
* Returns:
* None
*
*/
static void
scsp_free_hello(hp)
Scsp_hello *hp;
{
/*
* Return if there's nothing to free
*/
if (hp == (Scsp_hello *)0)
return;
/*
* Free the Hello message structure
*/
free(hp);
}
/*
* Free an SCSP message in internal format
*
* Arguments:
* msg pointer to input packet
*
* Returns:
* None
*
*/
void
scsp_free_msg(msg)
Scsp_msg *msg;
{
Scsp_ext *exp, *nexp;
/*
* Return if there's nothing to free
*/
if (msg == (Scsp_msg *)0)
return;
/*
* Free the message body
*/
switch(msg->sc_msg_type) {
case SCSP_CA_MSG:
scsp_free_ca(msg->sc_ca);
break;
case SCSP_CSU_REQ_MSG:
case SCSP_CSU_REPLY_MSG:
case SCSP_CSUS_MSG:
scsp_free_csu(msg->sc_csu_msg);
break;
case SCSP_HELLO_MSG:
scsp_free_hello(msg->sc_hello);
break;
}
/*
* Free any extensions
*/
for (exp = msg->sc_ext; exp; exp = nexp) {
nexp = exp->next;
free(exp);
}
/*
* Free the message structure
*/
free(msg);
}
/*
* Parse a Sender or Receiver ID
*
* Arguments:
* buff pointer to ID
* id_len length of ID
* idp pointer to structure to receive the ID
*
* Returns:
* 0 input was invalid
* else length of ID processed
*
*/
static int
scsp_parse_id(buff, id_len, idp)
char *buff;
int id_len;
Scsp_id *idp;
{
/*
* Sanity check
*/
if (!buff ||
id_len == 0 || id_len > SCSP_MAX_ID_LEN ||
!idp) {
return(0);
}
/*
* Save the ID length
*/
idp->id_len = id_len;
/*
* Get the ID
*/
bcopy(buff, idp->id, id_len);
/*
* Return the ID length
*/
return(id_len);
}
/*
* Parse the Mandatory Common Part of an SCSP input packet
*
* Arguments:
* buff pointer to mandatory common part
* pdu_len length of input packet
* mcp pointer to location of MCP in decoded record
*
* Returns:
* 0 input was invalid
* else length of MCP in message
*
*/
static int
scsp_parse_mcp(buff, pdu_len, mcp)
char *buff;
int pdu_len;
Scsp_mcp *mcp;
{
int len;
u_char *idp;
struct scsp_nmcp *smp;
/*
* Get the protocol ID
*/
smp = (struct scsp_nmcp *)buff;
mcp->pid = ntohs(smp->sm_pid);
if (mcp->pid < SCSP_PROTO_ATMARP ||
mcp->pid > SCSP_PROTO_LNNI) {
/* Protocol ID is invalid */
goto mcp_invalid;
}
/*
* Get the server group ID
*/
mcp->sgid = ntohs(smp->sm_sgid);
/*
* Get the flags
*/
mcp->flags = ntohs(smp->sm_flags);
/*
* Get the sender ID and length
*/
idp = (u_char *) ((caddr_t)smp + sizeof(struct scsp_nmcp));
len = scsp_parse_id(idp, smp->sm_sid_len, &mcp->sid);
if (len == 0) {
goto mcp_invalid;
}
/*
* Get the receiver ID and length
*/
idp += len;
len = scsp_parse_id(idp, smp->sm_rid_len, &mcp->rid);
if (len == 0) {
goto mcp_invalid;
}
/*
* Get the record count
*/
mcp->rec_cnt = ntohs(smp->sm_rec_cnt);
/*
* Return the length of data we processed
*/
return(sizeof(struct scsp_nmcp) + smp->sm_sid_len +
smp->sm_rid_len);
mcp_invalid:
return(0);
}
/*
* Parse an Extension
*
* Arguments:
* buff pointer to Extension
* pdu_len length of buffer
* expp pointer to location to receive pointer to the Extension
*
* Returns:
* 0 input was invalid
* else length of Extension processed
*
*/
static int
scsp_parse_ext(buff, pdu_len, expp)
char *buff;
int pdu_len;
Scsp_ext **expp;
{
int len;
struct scsp_next *sep;
Scsp_ext *exp;
/*
* Get memory for the extension
*/
sep = (struct scsp_next *)buff;
len = sizeof(Scsp_ext) + ntohs(sep->se_len);
exp = calloc(1, len);
if (exp == NULL)
goto ext_invalid;
/*
* Get the type
*/
exp->type = ntohs(sep->se_type);
/*
* Get the length
*/
exp->len = ntohs(sep->se_len);
/*
* Get the value
*/
if (exp->len > 0) {
bcopy((caddr_t)sep + sizeof(struct scsp_next),
(caddr_t)exp + sizeof(Scsp_ext),
exp->len);
}
/*
* Save a pointer to the extension and return the
* number of bytes processed
*/
*expp = exp;
return(sizeof(struct scsp_next) + exp->len);
ext_invalid:
if (exp) {
free(exp);
}
return(0);
}
/*
* Parse a Cache State Advertisement or Cache State Advertisement
* Summary record
*
* Arguments:
* buff pointer to CSA or CSAS record
* pdu_len length of input packet
* csapp pointer to location to put pointer to CSA or CSAS
*
* Returns:
* 0 input was invalid
* else length of record processed
*
*/
static int
scsp_parse_csa(buff, pdu_len, csapp)
char *buff;
int pdu_len;
Scsp_csa **csapp;
{
int len;
char *idp;
struct scsp_ncsa *scp;
Scsp_csa *csap = NULL;
/*
* Check the record length
*/
scp = (struct scsp_ncsa *)buff;
if (ntohs(scp->scs_len) < (sizeof(struct scsp_ncsa) +
scp->scs_ck_len + scp->scs_oid_len)) {
goto csa_invalid;
}
/*
* Get memory for the returned structure
*/
len = sizeof(Scsp_csa) + ntohs(scp->scs_len) -
sizeof(struct scsp_ncsa) - scp->scs_ck_len -
scp->scs_oid_len;
csap = calloc(1, len);
if (csap == NULL)
goto csa_invalid;
/*
* Get the hop count
*/
csap->hops = ntohs(scp->scs_hop_cnt);
/*
* Set the null flag
*/
csap->null = (ntohs(scp->scs_nfill) & SCSP_CSAS_NULL) != 0;
/*
* Get the sequence number
*/
csap->seq = get_long((u_char *)&scp->scs_seq);
/*
* Get the cache key
*/
if (scp->scs_ck_len == 0 ||
scp->scs_ck_len > SCSP_MAX_KEY_LEN) {
goto csa_invalid;
}
csap->key.key_len = scp->scs_ck_len;
idp = (char *) ((caddr_t)scp + sizeof(struct scsp_ncsa));
bcopy(idp, csap->key.key, scp->scs_ck_len);
/*
* Get the originator ID
*/
idp += scp->scs_ck_len;
len = scsp_parse_id(idp, scp->scs_oid_len, &csap->oid);
if (len == 0) {
goto csa_invalid;
}
/*
* Get the protocol-specific data, if present
*/
len = ntohs(scp->scs_len) - (sizeof(struct scsp_ncsa) +
scp->scs_ck_len + scp->scs_oid_len);
if (len > 0) {
idp += scp->scs_oid_len;
len = scsp_parse_atmarp(idp, len, &csap->atmarp_data);
if (len == 0)
goto csa_invalid;
}
/*
* Set a pointer to the MCP and return the length
* of data we processed
*/
*csapp = csap;
return(ntohs(scp->scs_len));
csa_invalid:
if (csap)
SCSP_FREE_CSA(csap);
return(0);
}
/*
* Parse a Cache Alignment message
*
* Arguments:
* buff pointer to start of CA in message
* pdu_len length of input packet
* capp pointer to location to put pointer to CA message
*
* Returns:
* 0 input was invalid
* else length of CA message processed
*
*/
static int
scsp_parse_ca(buff, pdu_len, capp)
char *buff;
int pdu_len;
Scsp_ca **capp;
{
int i, len, proc_len;
struct scsp_nca *scap;
Scsp_ca *cap;
Scsp_csa **csapp;
/*
* Get memory for the returned structure
*/
scap = (struct scsp_nca *)buff;
cap = calloc(1, sizeof(Scsp_ca));
if (cap == NULL)
goto ca_invalid;
/*
* Get the sequence number
*/
cap->ca_seq = get_long((u_char *)&scap->sca_seq);
proc_len = sizeof(scap->sca_seq);
buff += sizeof(scap->sca_seq);
/*
* Process the mandatory common part of the message
*/
len = scsp_parse_mcp(buff,
pdu_len - proc_len,
&cap->ca_mcp);
if (len == 0)
goto ca_invalid;
buff += len;
proc_len += len;
/*
* Set the flags
*/
cap->ca_m = (cap->ca_mcp.flags & SCSP_CA_M) != 0;
cap->ca_i = (cap->ca_mcp.flags & SCSP_CA_I) != 0;
cap->ca_o = (cap->ca_mcp.flags & SCSP_CA_O) != 0;
/*
* Get the CSAS records from the message
*/
for (i = 0, csapp = &cap->ca_csa_rec; i < cap->ca_mcp.rec_cnt;
i++, csapp = &(*csapp)->next) {
len = scsp_parse_csa(buff, pdu_len - proc_len, csapp);
buff += len;
proc_len += len;
}
/*
* Set the address of the CA message and
* return the length of processed data
*/
*capp = cap;
return(proc_len);
ca_invalid:
if (cap)
scsp_free_ca(cap);
return(0);
}
/*
* Parse the ATMARP-specific part of a CSA record
*
* Arguments:
* buff pointer to ATMARP part of CSU message
* pdu_len length of data to process
* acspp pointer to location to put pointer to CSU message
*
* Returns:
* 0 input was invalid
* else length of CSU Req message processed
*
*/
static int
scsp_parse_atmarp(buff, pdu_len, acspp)
char *buff;
int pdu_len;
Scsp_atmarp_csa **acspp;
{
int len, proc_len;
struct scsp_atmarp_ncsa *sacp;
Scsp_atmarp_csa *acsp = NULL;
/*
* Initial packet verification
*/
sacp = (struct scsp_atmarp_ncsa *)buff;
if ((sacp->sa_hrd != ntohs(ARP_ATMFORUM)) ||
(sacp->sa_pro != ntohs(ETHERTYPE_IP)))
goto acs_invalid;
/*
* Get memory for the returned structure
*/
acsp = calloc(1, sizeof(Scsp_atmarp_csa));
if (acsp == NULL)
goto acs_invalid;
/*
* Get state code
*/
acsp->sa_state = sacp->sa_state;
proc_len = sizeof(struct scsp_atmarp_ncsa);
/*
* Verify/gather source ATM address
*/
acsp->sa_sha.address_format = T_ATM_ABSENT;
acsp->sa_sha.address_length = 0;
if ((len = (sacp->sa_shtl & ARP_TL_LMASK)) != 0) {
if (sacp->sa_shtl & ARP_TL_E164) {
if (len > sizeof(Atm_addr_e164))
goto acs_invalid;
acsp->sa_sha.address_format = T_ATM_E164_ADDR;
} else {
if (len != sizeof(Atm_addr_nsap))
goto acs_invalid;
acsp->sa_sha.address_format = T_ATM_ENDSYS_ADDR;
}
acsp->sa_sha.address_length = len;
if (pdu_len < proc_len + len)
goto acs_invalid;
bcopy(&buff[proc_len], (char *)acsp->sa_sha.address,
len);
proc_len += len;
}
/*
* Verify/gather source ATM subaddress
*/
acsp->sa_ssa.address_format = T_ATM_ABSENT;
acsp->sa_ssa.address_length = 0;
if ((len = (sacp->sa_sstl & ARP_TL_LMASK)) != 0) {
if (((sacp->sa_sstl & ARP_TL_TMASK) != ARP_TL_NSAPA) ||
(len != sizeof(Atm_addr_nsap)))
goto acs_invalid;
acsp->sa_ssa.address_format = T_ATM_ENDSYS_ADDR;
acsp->sa_ssa.address_length = len;
if (pdu_len < proc_len + len)
goto acs_invalid;
bcopy(&buff[proc_len], (char *)acsp->sa_ssa.address,
len);
proc_len += len;
}
/*
* Verify/gather source IP address
*/
if ((len = sacp->sa_spln) != 0) {
if (len != sizeof(struct in_addr))
goto acs_invalid;
if (pdu_len < proc_len + len)
goto acs_invalid;
bcopy(&buff[proc_len], (char *)&acsp->sa_spa, len);
proc_len += len;
} else {
acsp->sa_spa.s_addr = 0;
}
/*
* Verify/gather target ATM address
*/
acsp->sa_tha.address_format = T_ATM_ABSENT;
acsp->sa_tha.address_length = 0;
if ((len = (sacp->sa_thtl & ARP_TL_LMASK)) != 0) {
if (sacp->sa_thtl & ARP_TL_E164) {
if (len > sizeof(Atm_addr_e164))
goto acs_invalid;
acsp->sa_tha.address_format = T_ATM_E164_ADDR;
} else {
if (len != sizeof(Atm_addr_nsap))
goto acs_invalid;
acsp->sa_tha.address_format = T_ATM_ENDSYS_ADDR;
}
acsp->sa_tha.address_length = len;
if (pdu_len < proc_len + len)
goto acs_invalid;
bcopy(&buff[proc_len], (char *)acsp->sa_tha.address,
len);
proc_len += len;
}
/*
* Verify/gather target ATM subaddress
*/
acsp->sa_tsa.address_format = T_ATM_ABSENT;
acsp->sa_tsa.address_length = 0;
if ((len = (sacp->sa_tstl & ARP_TL_LMASK)) != 0) {
if (((sacp->sa_tstl & ARP_TL_TMASK) != ARP_TL_NSAPA) ||
(len != sizeof(Atm_addr_nsap)))
goto acs_invalid;
acsp->sa_tsa.address_format = T_ATM_ENDSYS_ADDR;
acsp->sa_tsa.address_length = len;
if (pdu_len < proc_len + len)
goto acs_invalid;
bcopy(&buff[proc_len], (char *)acsp->sa_tsa.address,
len);
proc_len += len;
}
/*
* Verify/gather target IP address
*/
if ((len = sacp->sa_tpln) != 0) {
if (len != sizeof(struct in_addr))
goto acs_invalid;
if (pdu_len < proc_len + len)
goto acs_invalid;
bcopy(&buff[proc_len], (char *)&acsp->sa_tpa, len);
proc_len += len;
} else {
acsp->sa_tpa.s_addr = 0;
}
/*
* Verify packet length
*/
if (proc_len != pdu_len)
goto acs_invalid;
*acspp = acsp;
return(proc_len);
acs_invalid:
if (acsp)
free(acsp);
return(0);
}
/*
* Parse a Cache State Update Request, Cache State Update Reply, or
* Cache State Update Solicit message. These all have the same format,
* a Mandatory Common Part followed by a number of CSA or CSAS records.
*
* Arguments:
* buff pointer to start of CSU message
* pdu_len length of input packet
* csupp pointer to location to put pointer to CSU message
*
* Returns:
* 0 input was invalid
* else length of CSU Req message processed
*
*/
static int
scsp_parse_csu(buff, pdu_len, csupp)
char *buff;
int pdu_len;
Scsp_csu_msg **csupp;
{
int i, len, proc_len;
Scsp_csu_msg *csup;
Scsp_csa **csapp;
/*
* Get memory for the returned structure
*/
csup = calloc(1, sizeof(Scsp_csu_msg));
if (csup == NULL)
goto csu_invalid;
/*
* Process the mandatory common part of the message
*/
len = scsp_parse_mcp(buff, pdu_len, &csup->csu_mcp);
if (len == 0)
goto csu_invalid;
buff += len;
proc_len = len;
/*
* Get the CSAS records from the message
*/
for (i = 0, csapp = &csup->csu_csa_rec;
i < csup->csu_mcp.rec_cnt;
i++, csapp = &(*csapp)->next) {
len = scsp_parse_csa(buff, pdu_len - proc_len, csapp);
buff += len;
proc_len += len;
}
/*
* Set the address of the CSU Req message and
* return the length of processed data
*/
*csupp = csup;
return(proc_len);
csu_invalid:
if (csup)
scsp_free_csu(csup);
return(0);
}
/*
* Parse a Hello message
*
* Arguments:
* buff pointer to start of Hello in message
* pdu_len length of input packet
* hpp pointer to location to put pointer to Hello message
*
* Returns:
* 0 input was invalid
* else length of Hello message processed
*
*/
static int
scsp_parse_hello(buff, pdu_len, hpp)
char *buff;
int pdu_len;
Scsp_hello **hpp;
{
int i, len, proc_len;
struct scsp_nhello *shp = (struct scsp_nhello *)buff;
Scsp_hello *hp;
Scsp_id *idp;
Scsp_id **ridpp;
/*
* Get memory for the returned structure
*/
hp = calloc(1, sizeof(Scsp_hello));
if (hp == NULL)
goto hello_invalid;
/*
* Get the hello interval
*/
hp->hello_int = ntohs(shp->sch_hi);
/*
* Get the dead factor
*/
hp->dead_factor = ntohs(shp->sch_df);
/*
* Get the family ID
*/
hp->family_id = ntohs(shp->sch_fid);
/*
* Process the mandatory common part of the message
*/
proc_len = sizeof(struct scsp_nhello) -
sizeof(struct scsp_nmcp);
buff += proc_len;
len = scsp_parse_mcp(buff, pdu_len - proc_len,
&hp->hello_mcp);
if (len == 0)
goto hello_invalid;
buff += len;
proc_len += len;
/*
* Get additional receiver ID records from the message
*/
for (i = 0, ridpp = &hp->hello_mcp.rid.next;
i < hp->hello_mcp.rec_cnt;
i++, ridpp = &idp->next) {
idp = calloc(1, sizeof(Scsp_id));
if (idp == NULL)
goto hello_invalid;
len = scsp_parse_id(buff,
hp->hello_mcp.rid.id_len,
idp);
if (len == 0) {
free(idp);
goto hello_invalid;
}
buff += len;
proc_len += len;
*ridpp = idp;
}
/*
* Set the address of the CA message and
* return the length of processed data
*/
*hpp = hp;
return(proc_len);
hello_invalid:
if (hp)
scsp_free_hello(hp);
return(0);
}
/*
* Parse an SCSP input packet
*
* Arguments:
* buff pointer to input packet
* pdu_len length of input packet
*
* Returns:
* NULL input packet was invalid
* else pointer to packet in internal format
*
*/
Scsp_msg *
scsp_parse_msg(buff, pdu_len)
char *buff;
int pdu_len;
{
int ext_off, len, plen;
struct scsp_nhdr *shp;
Scsp_msg *msg = (Scsp_msg *)0;
Scsp_ext **expp;
/*
* Check the message checksum
*/
if (ip_checksum(buff, pdu_len) != 0) {
/*
* Checksum was bad--discard the message
*/
goto ignore;
}
/*
* Allocate storage for the message
*/
msg = calloc(1, sizeof(Scsp_msg));
if (msg == NULL)
goto ignore;
/*
* Decode the fixed header
*
* Check the version
*/
shp = (struct scsp_nhdr *)buff;
if (shp->sh_ver != SCSP_VER_1)
goto ignore;
/*
* Get the message type
*/
msg->sc_msg_type = shp->sh_type;
/*
* Get and check the length
*/
len = ntohs(shp->sh_len);
if (len != pdu_len)
goto ignore;
/*
* Get the extension offset
*/
ext_off = ntohs(shp->sh_ext_off);
/*
* Decode the body of the message, depending on the type
*/
buff += sizeof(struct scsp_nhdr);
len -= sizeof(struct scsp_nhdr);
switch(msg->sc_msg_type) {
case SCSP_CA_MSG:
plen = scsp_parse_ca(buff, len, &msg->sc_ca);
break;
case SCSP_CSU_REQ_MSG:
case SCSP_CSU_REPLY_MSG:
case SCSP_CSUS_MSG:
plen = scsp_parse_csu(buff, len, &msg->sc_csu_msg);
break;
case SCSP_HELLO_MSG:
plen = scsp_parse_hello(buff, len, &msg->sc_hello);
break;
default:
goto ignore;
}
if (plen == 0) {
goto ignore;
}
buff += plen;
len -= plen;
/*
* Decode any extensions
*/
if (ext_off != 0) {
for (expp = &msg->sc_ext; len > 0;
expp = &(*expp)->next) {
plen = scsp_parse_ext(buff, len, expp);
if (plen == 0) {
goto ignore;
}
buff += plen;
len -= plen;
}
}
/*
* Make sure we handled the whole message
*/
if (len != 0) {
goto ignore;
}
/*
* Return the address of the SCSP message in internal format
*/
return(msg);
ignore:
if (msg)
scsp_free_msg(msg);
return(Scsp_msg *)0;
}