/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
** File:        pripv6.c
** Description: Support for various functions unique to IPv6
*/
#include "primpl.h"
#include <string.h>

#if !defined(_PR_INET6) || defined(_PR_INET6_PROBE)

static PRIOMethods ipv6_to_v4_tcpMethods;
static PRIOMethods ipv6_to_v4_udpMethods;
static PRDescIdentity _pr_ipv6_to_ipv4_id;
extern PRBool IsValidNetAddr(const PRNetAddr *addr);
extern const PRIPv6Addr _pr_in6addr_any;
extern const PRIPv6Addr _pr_in6addr_loopback;

/*
 * convert an IPv4-mapped IPv6 addr to an IPv4 addr
 */
static void _PR_ConvertToIpv4NetAddr(const PRNetAddr *src_v6addr,
                                     PRNetAddr *dst_v4addr)
{
    const PRUint8 *srcp;

    PR_ASSERT(PR_AF_INET6 == src_v6addr->ipv6.family);

    if (PR_IsNetAddrType(src_v6addr, PR_IpAddrV4Mapped)) {
        srcp = src_v6addr->ipv6.ip.pr_s6_addr;
        memcpy((char *) &dst_v4addr->inet.ip, srcp + 12, 4);
    } else if (PR_IsNetAddrType(src_v6addr, PR_IpAddrAny)) {
        dst_v4addr->inet.ip = htonl(INADDR_ANY);
    } else if (PR_IsNetAddrType(src_v6addr, PR_IpAddrLoopback)) {
        dst_v4addr->inet.ip = htonl(INADDR_LOOPBACK);
    }
    dst_v4addr->inet.family = PR_AF_INET;
    dst_v4addr->inet.port = src_v6addr->ipv6.port;
}

/*
 * convert an IPv4 addr to an IPv4-mapped IPv6 addr
 */
static void _PR_ConvertToIpv6NetAddr(const PRNetAddr *src_v4addr,
                                     PRNetAddr *dst_v6addr)
{
    PRUint8 *dstp;

    PR_ASSERT(PR_AF_INET == src_v4addr->inet.family);
    dst_v6addr->ipv6.family = PR_AF_INET6;
    dst_v6addr->ipv6.port = src_v4addr->inet.port;

    if (htonl(INADDR_ANY) == src_v4addr->inet.ip) {
        dst_v6addr->ipv6.ip = _pr_in6addr_any;
    } else {
        dstp = dst_v6addr->ipv6.ip.pr_s6_addr;
        memset(dstp, 0, 10);
        memset(dstp + 10, 0xff, 2);
        memcpy(dstp + 12,(char *) &src_v4addr->inet.ip, 4);
    }
}

static PRStatus PR_CALLBACK Ipv6ToIpv4SocketBind(PRFileDesc *fd,
        const PRNetAddr *addr)
{
    PRNetAddr tmp_ipv4addr;
    const PRNetAddr *tmp_addrp;
    PRFileDesc *lo = fd->lower;

    if (PR_AF_INET6 != addr->raw.family) {
        PR_SetError(PR_ADDRESS_NOT_SUPPORTED_ERROR, 0);
        return PR_FAILURE;
    }
    if (PR_IsNetAddrType(addr, PR_IpAddrV4Mapped) ||
        PR_IsNetAddrType(addr, PR_IpAddrAny)) {
        _PR_ConvertToIpv4NetAddr(addr, &tmp_ipv4addr);
        tmp_addrp = &tmp_ipv4addr;
    } else {
        PR_SetError(PR_NETWORK_UNREACHABLE_ERROR, 0);
        return PR_FAILURE;
    }
    return((lo->methods->bind)(lo,tmp_addrp));
}

static PRStatus PR_CALLBACK Ipv6ToIpv4SocketConnect(
    PRFileDesc *fd, const PRNetAddr *addr, PRIntervalTime timeout)
{
    PRNetAddr tmp_ipv4addr;
    const PRNetAddr *tmp_addrp;

    if (PR_AF_INET6 != addr->raw.family) {
        PR_SetError(PR_ADDRESS_NOT_SUPPORTED_ERROR, 0);
        return PR_FAILURE;
    }
    if (PR_IsNetAddrType(addr, PR_IpAddrV4Mapped) ||
        PR_IsNetAddrType(addr, PR_IpAddrLoopback)) {
        _PR_ConvertToIpv4NetAddr(addr, &tmp_ipv4addr);
        tmp_addrp = &tmp_ipv4addr;
    } else {
        PR_SetError(PR_NETWORK_UNREACHABLE_ERROR, 0);
        return PR_FAILURE;
    }
    return (fd->lower->methods->connect)(fd->lower, tmp_addrp, timeout);
}

static PRInt32 PR_CALLBACK Ipv6ToIpv4SocketSendTo(
    PRFileDesc *fd, const void *buf, PRInt32 amount,
    PRIntn flags, const PRNetAddr *addr, PRIntervalTime timeout)
{
    PRNetAddr tmp_ipv4addr;
    const PRNetAddr *tmp_addrp;

    if (PR_AF_INET6 != addr->raw.family) {
        PR_SetError(PR_ADDRESS_NOT_SUPPORTED_ERROR, 0);
        return PR_FAILURE;
    }
    if (PR_IsNetAddrType(addr, PR_IpAddrV4Mapped) ||
        PR_IsNetAddrType(addr, PR_IpAddrLoopback)) {
        _PR_ConvertToIpv4NetAddr(addr, &tmp_ipv4addr);
        tmp_addrp = &tmp_ipv4addr;
    } else {
        PR_SetError(PR_NETWORK_UNREACHABLE_ERROR, 0);
        return PR_FAILURE;
    }
    return (fd->lower->methods->sendto)(
               fd->lower, buf, amount, flags, tmp_addrp, timeout);
}

static PRFileDesc* PR_CALLBACK Ipv6ToIpv4SocketAccept (
    PRFileDesc *fd, PRNetAddr *addr, PRIntervalTime timeout)
{
    PRStatus rv;
    PRFileDesc *newfd;
    PRFileDesc *newstack;
    PRNetAddr tmp_ipv4addr;
    PRNetAddr *addrlower = NULL;

    PR_ASSERT(fd != NULL);
    PR_ASSERT(fd->lower != NULL);

    newstack = PR_NEW(PRFileDesc);
    if (NULL == newstack)
    {
        PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
        return NULL;
    }
    *newstack = *fd;  /* make a copy of the accepting layer */

    if (addr) {
        addrlower = &tmp_ipv4addr;
    }
    newfd = (fd->lower->methods->accept)(fd->lower, addrlower, timeout);
    if (NULL == newfd)
    {
        PR_DELETE(newstack);
        return NULL;
    }
    if (addr) {
        _PR_ConvertToIpv6NetAddr(&tmp_ipv4addr, addr);
    }

    rv = PR_PushIOLayer(newfd, PR_TOP_IO_LAYER, newstack);
    PR_ASSERT(PR_SUCCESS == rv);
    return newfd;  /* that's it */
}

static PRInt32 PR_CALLBACK Ipv6ToIpv4SocketAcceptRead(PRFileDesc *sd,
        PRFileDesc **nd, PRNetAddr **ipv6_raddr, void *buf, PRInt32 amount,
        PRIntervalTime timeout)
{
    PRInt32 nbytes;
    PRStatus rv;
    PRNetAddr tmp_ipv4addr;
    PRFileDesc *newstack;

    PR_ASSERT(sd != NULL);
    PR_ASSERT(sd->lower != NULL);

    newstack = PR_NEW(PRFileDesc);
    if (NULL == newstack)
    {
        PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
        return -1;
    }
    *newstack = *sd;  /* make a copy of the accepting layer */

    nbytes = sd->lower->methods->acceptread(
                 sd->lower, nd, ipv6_raddr, buf, amount, timeout);
    if (-1 == nbytes)
    {
        PR_DELETE(newstack);
        return nbytes;
    }
    tmp_ipv4addr = **ipv6_raddr;    /* copy */
    _PR_ConvertToIpv6NetAddr(&tmp_ipv4addr, *ipv6_raddr);

    /* this PR_PushIOLayer call cannot fail */
    rv = PR_PushIOLayer(*nd, PR_TOP_IO_LAYER, newstack);
    PR_ASSERT(PR_SUCCESS == rv);
    return nbytes;
}

static PRStatus PR_CALLBACK Ipv6ToIpv4SocketGetName(PRFileDesc *fd,
        PRNetAddr *ipv6addr)
{
    PRStatus result;
    PRNetAddr tmp_ipv4addr;

    result = (fd->lower->methods->getsockname)(fd->lower, &tmp_ipv4addr);
    if (PR_SUCCESS == result) {
        _PR_ConvertToIpv6NetAddr(&tmp_ipv4addr, ipv6addr);
        PR_ASSERT(IsValidNetAddr(ipv6addr) == PR_TRUE);
    }
    return result;
}

static PRStatus PR_CALLBACK Ipv6ToIpv4SocketGetPeerName(PRFileDesc *fd,
        PRNetAddr *ipv6addr)
{
    PRStatus result;
    PRNetAddr tmp_ipv4addr;

    result = (fd->lower->methods->getpeername)(fd->lower, &tmp_ipv4addr);
    if (PR_SUCCESS == result) {
        _PR_ConvertToIpv6NetAddr(&tmp_ipv4addr, ipv6addr);
        PR_ASSERT(IsValidNetAddr(ipv6addr) == PR_TRUE);
    }
    return result;
}

static PRInt32 PR_CALLBACK Ipv6ToIpv4SocketRecvFrom(PRFileDesc *fd, void *buf,
        PRInt32 amount, PRIntn flags, PRNetAddr *ipv6addr,
        PRIntervalTime timeout)
{
    PRNetAddr tmp_ipv4addr;
    PRInt32 result;

    result = (fd->lower->methods->recvfrom)(
                 fd->lower, buf, amount, flags, &tmp_ipv4addr, timeout);
    if (-1 != result) {
        _PR_ConvertToIpv6NetAddr(&tmp_ipv4addr, ipv6addr);
        PR_ASSERT(IsValidNetAddr(ipv6addr) == PR_TRUE);
    }
    return result;
}

#if defined(_PR_INET6_PROBE)
static PRBool ipv6_is_present;
PR_EXTERN(PRBool) _pr_test_ipv6_socket(void);

#if !defined(_PR_INET6) && defined(_PR_HAVE_GETIPNODEBYNAME)
extern PRStatus _pr_find_getipnodebyname(void);
#endif

#if !defined(_PR_INET6) && defined(_PR_HAVE_GETADDRINFO)
extern PRStatus _pr_find_getaddrinfo(void);
#endif

static PRBool
_pr_probe_ipv6_presence(void)
{
#if !defined(_PR_INET6) && defined(_PR_HAVE_GETIPNODEBYNAME)
    if (_pr_find_getipnodebyname() != PR_SUCCESS) {
        return PR_FALSE;
    }
#endif

#if !defined(_PR_INET6) && defined(_PR_HAVE_GETADDRINFO)
    if (_pr_find_getaddrinfo() != PR_SUCCESS) {
        return PR_FALSE;
    }
#endif

    return _pr_test_ipv6_socket();
}
#endif  /* _PR_INET6_PROBE */

static PRCallOnceType _pr_init_ipv6_once;

static PRStatus PR_CALLBACK _pr_init_ipv6(void)
{
    const PRIOMethods *stubMethods;

#if defined(_PR_INET6_PROBE)
    ipv6_is_present = _pr_probe_ipv6_presence();
    if (ipv6_is_present) {
        return PR_SUCCESS;
    }
#endif

    _pr_ipv6_to_ipv4_id = PR_GetUniqueIdentity("Ipv6_to_Ipv4 layer");
    PR_ASSERT(PR_INVALID_IO_LAYER != _pr_ipv6_to_ipv4_id);

    stubMethods = PR_GetDefaultIOMethods();

    ipv6_to_v4_tcpMethods = *stubMethods;  /* first get the entire batch */
    /* then override the ones we care about */
    ipv6_to_v4_tcpMethods.connect = Ipv6ToIpv4SocketConnect;
    ipv6_to_v4_tcpMethods.bind = Ipv6ToIpv4SocketBind;
    ipv6_to_v4_tcpMethods.accept = Ipv6ToIpv4SocketAccept;
    ipv6_to_v4_tcpMethods.acceptread = Ipv6ToIpv4SocketAcceptRead;
    ipv6_to_v4_tcpMethods.getsockname = Ipv6ToIpv4SocketGetName;
    ipv6_to_v4_tcpMethods.getpeername = Ipv6ToIpv4SocketGetPeerName;
    /*
        ipv6_to_v4_tcpMethods.getsocketoption = Ipv6ToIpv4GetSocketOption;
        ipv6_to_v4_tcpMethods.setsocketoption = Ipv6ToIpv4SetSocketOption;
    */
    ipv6_to_v4_udpMethods = *stubMethods;  /* first get the entire batch */
    /* then override the ones we care about */
    ipv6_to_v4_udpMethods.connect = Ipv6ToIpv4SocketConnect;
    ipv6_to_v4_udpMethods.bind = Ipv6ToIpv4SocketBind;
    ipv6_to_v4_udpMethods.sendto = Ipv6ToIpv4SocketSendTo;
    ipv6_to_v4_udpMethods.recvfrom = Ipv6ToIpv4SocketRecvFrom;
    ipv6_to_v4_udpMethods.getsockname = Ipv6ToIpv4SocketGetName;
    ipv6_to_v4_udpMethods.getpeername = Ipv6ToIpv4SocketGetPeerName;
    /*
        ipv6_to_v4_udpMethods.getsocketoption = Ipv6ToIpv4GetSocketOption;
        ipv6_to_v4_udpMethods.setsocketoption = Ipv6ToIpv4SetSocketOption;
    */
    return PR_SUCCESS;
}

#if defined(_PR_INET6_PROBE)
PRBool _pr_ipv6_is_present(void)
{
    if (PR_CallOnce(&_pr_init_ipv6_once, _pr_init_ipv6) != PR_SUCCESS) {
        return PR_FALSE;
    }
    return ipv6_is_present;
}
#endif

PR_IMPLEMENT(PRStatus) _pr_push_ipv6toipv4_layer(PRFileDesc *fd)
{
    PRFileDesc *ipv6_fd = NULL;

    if (PR_CallOnce(&_pr_init_ipv6_once, _pr_init_ipv6) != PR_SUCCESS) {
        return PR_FAILURE;
    }

    /*
     * For platforms with no support for IPv6
     * create layered socket for IPv4-mapped IPv6 addresses
     */
    if (fd->methods->file_type == PR_DESC_SOCKET_TCP)
        ipv6_fd = PR_CreateIOLayerStub(_pr_ipv6_to_ipv4_id,
                                       &ipv6_to_v4_tcpMethods);
    else
        ipv6_fd = PR_CreateIOLayerStub(_pr_ipv6_to_ipv4_id,
                                       &ipv6_to_v4_udpMethods);
    if (NULL == ipv6_fd) {
        goto errorExit;
    }
    ipv6_fd->secret = NULL;

    if (PR_PushIOLayer(fd, PR_TOP_IO_LAYER, ipv6_fd) == PR_FAILURE) {
        goto errorExit;
    }

    return PR_SUCCESS;
errorExit:

    if (ipv6_fd) {
        ipv6_fd->dtor(ipv6_fd);
    }
    return PR_FAILURE;
}

#endif /* !defined(_PR_INET6) || defined(_PR_INET6_PROBE) */