ipsec_ipv6_utilities.c

ipsec PNE 3.3 source code, running at more than vxworks6.x version.

/* ipsec_ipv6_utilities.c - utlity routines for getting ipv6 header info */

/******************************************************************************/
/* Copyright 2000-2001 Wind River Systems, Inc. 							  */
/******************************************************************************/

/*
modification history
--------------------
02b,12may05,???  Added return value to fix compiler warning
02a,11nov04,msa  Removed dead code.
01i,08jul04,jfb  Rebased from ipsec-nortel_fuzzy_bunny_slippers-int.cg
01h,12jun03,rparkhil added support for STACK_NAME
01g,25Apr03,sam(teamf1)	added missing function header.
01f,24apr03,sam(teamf1) code cleanup.
01f,05mar03,mhb(teamf1) added break in the switch in
            ipsec_ipv6_extns_get_fragment_header.
01e,13jan03,mhb(teamf1) fixed DIAB compilation error.
01d,10jan03,mhb(teamf1) added the function ipsecIpv6ExtnsFragmentHdrGet
01c,07Jan03,mhb(teamf1) changed vxworks.h to vxWorks.h in includes for Solaris
                        build
01b,11nov02,mhb(teamf1) fixed endian related bugs.
01a,7Sep02,rks(teamf1)  written 

*/

/*
DESCRIPTION
This file has the utility routines for traversing the ipv6 packet and getting 
the lengths of the headers,pointers to the headers and protocol types of the
headers following the ipv6 header.
*/

/* include files */
#include "vxWorks.h"

#include <netinet/in.h>

#include "ipsecP.h"
#include "ipsec_print_routines.h"

#if STACK_NAME == STACK_NAME_V4_V6 && defined (INET6)
#include "ipsec_ipv6_utilities.h"

LOCAL UCHAR *mbufDataPtrAtOffset
    (
    struct mbuf *m,
    int offset
    );

/******************************************************************************
* mbufDataPtrAtOffset - sets the mbuf data and length pointer to the offset
*							specified.
* This routine sets the mbuf data and length pointer to the offset specified.
*
* NOMANUAL
*
* RETURNS : byte pointer to the offset in the mbuf data.
*/

LOCAL UCHAR *mbufDataPtrAtOffset
    (
    struct mbuf *m, /* pointer to mbuf */
    int offset      /* offset */
    )
    {
    while (m)
        {
        if (offset >= m->m_len)
            {
            m = m->m_next;
            offset -= m->m_len;
            }
        else
            return ((UCHAR *)m->m_data + offset);
        }

    ipsec_printf (IPSEC_WARNING_PRINTF, "IPsec: offset outside of mbuf in \
func mbufDataPtrAtOffset\n");
    return NULL;
    }

/******************************************************************************
* ipsecIpv6HdrLenGet - gets the total length of the ipv6 header. 
* 
* This routine gets the length of the extension header (prior to
* AH,ESP,Transport protocol headers). The hdrlen calculation is required by
* build_traffic_info function to pull ip+tcp header into a single mbuf.	
* 
* NOMANUAL
*
* RETURNS : ipv6 header length.
*/
int ipsecIpv6HdrLenGet
    (
    struct mbuf *m,     /* pointer to mbuf */
    struct ip6_hdr *ip6 /* ipv6 header */
    )
    {
    char *p_nxt_hdr;
    int nxt_hdr;
    int ip6_hlen;
    int ip6_hlen_max;
    int ext_hlen;
    int hdr_len_calculation_done;

    if (ip6 == NULL)
        {
        ip6 = (struct ip6_hdr *)m->m_data;
        }

    ip6_hlen = sizeof (struct ip6_hdr);
    nxt_hdr = ip6->ip6_nxt;
    p_nxt_hdr = (char *)(ip6)+ip6_hlen;
    ip6_hlen_max = sizeof (struct ip6_hdr) + ntohs (ip6->ip6_plen);
    hdr_len_calculation_done = 0;

    while ((!hdr_len_calculation_done) && ip6_hlen < ip6_hlen_max)
        {
        switch (nxt_hdr)
            {
            case IPPROTO_HOPOPTS:
            case IPPROTO_DSTOPTS:
            case IPPROTO_ROUTING:
                if (m != NULL)
                    {
                    nxt_hdr = *(mbufDataPtrAtOffset (m, ip6_hlen));

                    /* The length feild in the case of routing ,hop by 
                     * hop,destination extension headers is the header
                     * length in 8-octet units,not counting the first 8
                     * octets.
                     */
                    ext_hlen = (8 + ((*(mbufDataPtrAtOffset (m, ip6_hlen + 1))) * 8));
                    }
                else
                    {
                    nxt_hdr = *(p_nxt_hdr);
                    ext_hlen = 8 + (*(p_nxt_hdr + 1)) * 8;
                    }

                break;

            case IPPROTO_FRAGMENT:

                /* The Length of the fragment header is 8 bytes */
                ext_hlen = 8;
                hdr_len_calculation_done = 1;
                break;

            case IPPROTO_AH:
            case IPPROTO_ESP:
            default:
                ext_hlen = 0;
                hdr_len_calculation_done = 1;
            }

        p_nxt_hdr += ext_hlen;
        ip6_hlen += ext_hlen;
        }
    return ip6_hlen;
    }

/******************************************************************************
* ipsecIpv6ExtnHdrLenGet - gets the length of the ipv6 extension headers.
*
* Gets the length of the ipv6 extension headers.
*
* NOMANUAL
*
* RETURNS : length of the extension headers.
*
*/
int ipsecIpv6ExtnHdrLenGet
    (
    struct ip6_hdr *ip6 /* ipv6 header */
    )
    {
    char *p_nxt_hdr;
    int nxt_hdr;
    int ip6_hlen;
    int ip6_hlen_max;
    int ext_hlen;
    int hdr_len_calculation_done;
    UCHAR second_dst_opt = 0;

    nxt_hdr = ip6->ip6_nxt;
    p_nxt_hdr = (char *)(ip6)+sizeof (struct ip6_hdr);
    ip6_hlen_max = sizeof (struct ip6_hdr) + ntohs (ip6->ip6_plen);

    hdr_len_calculation_done = 0;
    ip6_hlen = 0;

    while ((!hdr_len_calculation_done) && ip6_hlen < ip6_hlen_max)
        {
        switch (nxt_hdr)
            {
            case IPPROTO_DSTOPTS:
                if (second_dst_opt)
                    {
                    ext_hlen = 0;
                    hdr_len_calculation_done = 1;
                    break;
                    }

                second_dst_opt = 1;

            case IPPROTO_HOPOPTS:
            case IPPROTO_ROUTING:
                nxt_hdr = *(p_nxt_hdr);

                /* The length feild in the case of routing ,hop by 
                 * hop ,destination extension headers is the header
                 * length in 8-octet units,not counting the first 8
                 * octets.
                 */
                ext_hlen = (8 + (*(p_nxt_hdr + 1)) * 8);
                break;

            case IPPROTO_FRAGMENT:

                /* The Length of the fragment header is 8 bytes */
                ext_hlen = 8;
                hdr_len_calculation_done = 1;
                break;

            case IPPROTO_AH:
            case IPPROTO_ESP:
            default:
                ext_hlen = 0;
                hdr_len_calculation_done = 1;
                break;
            }

        p_nxt_hdr += ext_hlen;
        ip6_hlen += ext_hlen;
        }
    return ip6_hlen;
    }

/******************************************************************************
* ipsecIpv6ExtnsNextHdrSet - This sets the next header field of the extension 
* 							 header.
* The next header field of the extension header is set to the next_hdr value
* which is sent as the third argument.
* 
* NOMANUAL	
* 
* RETURNS : N/A
*/
void ipsecIpv6ExtnsNextHdrSet
    (
    UCHAR first_hdr,
    UCHAR *p_extn_hdr,
    UCHAR next_hdr,
    USHORT extns_tot_len
    )
    {
    USHORT ext_hlen = 0;
    USHORT len = 0;
    UCHAR nxt_hdr = first_hdr;

    /* find last extension header */
    while (1)
        {
        switch (nxt_hdr)
            {
            case IPPROTO_HOPOPTS:
            case IPPROTO_DSTOPTS:
            case IPPROTO_ROUTING:

                /* The length feild in the case of routing ,hop by 
                 * hop ,destination extension headers is the header
                 * length in 8-octet units,not counting the first 8
                 * octets.
                 */
                ext_hlen = (8 + (*(p_extn_hdr + 1)) * 8);
                break;

            case IPPROTO_FRAGMENT:

                /* The Length of the fragment header is 8 bytes */
                ext_hlen = 8;
                break;

            case IPPROTO_AH:
            case IPPROTO_ESP:
            default:
                ipsec_printf (IPSEC_WARNING_PRINTF, "IPSEC: Unexpected extension header !!\n");
                return;
            }

        len += ext_hlen;

        if (len >= extns_tot_len)
            {
            break;
            }

        nxt_hdr = *(p_extn_hdr);
        p_extn_hdr += ext_hlen;
        }
    *(p_extn_hdr) = next_hdr;
    }

/******************************************************************************
* ipsecIpv6ExtnsTransportProtocolFind - gets the transport protocol from 
* 											the packet. 
*
* This function iterates through all the extension headers and finds the 
* transport protocol from the last extension header.
*
* NOMANUAL
*
* RETURNS : N/A
*/
int ipsecIpv6ExtnsTransportProtocolFind
    (
    UCHAR first_hdr,
    UCHAR *p_extns
    )
    {
    USHORT ext_hlen = 0;
    UCHAR nxt_hdr = first_hdr;

    /* find last extension header */
    while (1)
        {
        switch (nxt_hdr)
            {
            case IPPROTO_HOPOPTS:
            case IPPROTO_DSTOPTS:
            case IPPROTO_ROUTING:

                /* The length feild in the case of routing ,hop by 
                 * hop ,destination extension headers is the header
                 * length in 8-octet units,not counting the first 8
                 * octets.
                 */
                ext_hlen = (8 + (*(p_extns + 1)) * 8);
                break;

            case IPPROTO_FRAGMENT:

                /* The Length of the fragment header is 8 bytes */
                ext_hlen = 8;
                break;

            case IPPROTO_AH:
            case IPPROTO_ESP:
            default:
                return nxt_hdr;
            }

        nxt_hdr = *(p_extns);
        p_extns += ext_hlen;
        }

    /* code is not expected to reach here */