#include <net-snmp/net-snmp-config.h>

#ifdef NETSNMP_TRANSPORT_TCPIPV6_DOMAIN

#include <net-snmp/types.h>

#include "snmpIPBaseDomain.h"

#include <net-snmp/library/snmpTCPIPv6Domain.h>

#include <stdio.h>

#include <sys/types.h>

#include <errno.h>

#ifdef HAVE_STRING_H

#include <string.h>

#else

#include <strings.h>

#endif

#ifdef HAVE_STDLIB_H

#include <stdlib.h>

#endif

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#ifdef HAVE_SYS_SOCKET_H

#include <sys/socket.h>

#endif

#ifdef HAVE_NETINET_IN_H

#include <netinet/in.h>

#endif

#ifdef HAVE_ARPA_INET_H

#include <arpa/inet.h>

#endif

#ifdef HAVE_NETDB_H

#include <netdb.h>

#endif

#ifdef HAVE_FCNTL_H

#include <fcntl.h>

#endif

#include <net-snmp/types.h>

#include <net-snmp/output_api.h>

#include <net-snmp/config_api.h>

#include <net-snmp/library/snmp.h>

#include <net-snmp/library/snmp_transport.h>

#include <net-snmp/library/snmpSocketBaseDomain.h>

#include <net-snmp/library/snmpTCPBaseDomain.h>

#include <net-snmp/library/tools.h>

#ifndef NETSNMP_NO_SYSTEMD

#include <net-snmp/library/sd-daemon.h>

#endif

#include "inet_ntop.h"

/*

 * needs to be in sync with the definitions in snmplib/snmpTCPDomain.c

 * and perl/agent/agent.xs

 */

typedef netsnmp_indexed_addr_pair netsnmp_udp_addr_pair;

const oid netsnmp_TCPIPv6Domain[] = { TRANSPORT_DOMAIN_TCP_IPV6 };

static netsnmp_tdomain tcp6Domain;

/*

 * Return a string representing the address in data, or else the "far end"

 * address if data is NULL.  

 */

static char *

netsnmp_tcp6_fmtaddr(netsnmp_transport *t, const void *data, int len)

{

    return netsnmp_ipv6_fmtaddr("TCP/IPv6", t, data, len);

}

static NETSNMP_SOCKET

netsnmp_tcp6_accept(netsnmp_transport *t)

{

    netsnmp_udp_addr_pair *addr_pair;

    struct sockaddr       *farend;

    NETSNMP_SOCKET         newsock = NETSNMP_INVALID_SOCKET;

    socklen_t              farendlen;

    addr_pair = calloc(1, sizeof(*addr_pair));

    if (addr_pair == NULL) {

        /*

         * Indicate that the acceptance of this socket failed.  

         */

        DEBUGMSGTL(("netsnmp_tcp6", "accept: malloc failed\n"));

        return NETSNMP_INVALID_SOCKET;

    }

    farend = &addr_pair->remote_addr.sa;

    farendlen = sizeof(addr_pair->remote_addr.sin6);

    if (t && NETSNMP_IS_VALID_SOCKET(t->sock)) {

        newsock = accept(t->sock, farend, &farendlen);

        if (!NETSNMP_IS_VALID_SOCKET(newsock)) {

            DEBUGMSGTL(("netsnmp_tcp6", "accept failed errno %d \"%s\"\n",

                        errno, strerror(errno)));

            free(addr_pair);

            return newsock;

        }

        free(t->data);

        t->data = addr_pair;

        t->data_length = sizeof(netsnmp_udp_addr_pair);

        DEBUGIF("netsnmp_tcp6") {

            char *str = netsnmp_tcp6_fmtaddr(NULL, addr_pair,

                                             sizeof(netsnmp_udp_addr_pair));

            DEBUGMSGTL(("netsnmp_tcp6", "accept succeeded (from %s)\n", str));

            free(str);

        }

        /*

         * Try to make the new socket blocking.  

         */

        if (netsnmp_set_non_blocking_mode(newsock, FALSE) < 0)

            DEBUGMSGTL(("netsnmp_tcp6",

                        "accept: couldn't f_getfl of fd %" NETSNMP_FMT_SKT "\n",

                        newsock));

        netsnmp_set_tcp_nodelay(newsock, 1);

        /*

         * Allow user to override the send and receive buffers. Default is

         * to use os default.  Don't worry too much about errors --

         * just plough on regardless.  

         */

        netsnmp_sock_buffer_set(newsock, SO_SNDBUF, 1, 0);

        netsnmp_sock_buffer_set(newsock, SO_RCVBUF, 1, 0);

        return newsock;

    } else {

        free(addr_pair);

        return NETSNMP_INVALID_SOCKET;

    }

}

/*

 * Open a TCP/IPv6-based transport for SNMP.  Local is TRUE if addr is the

 * local address to bind to (i.e. this is a server-type session); otherwise

 * addr is the remote address to send things to.  

 */

netsnmp_transport *

netsnmp_tcp6_transport(const struct netsnmp_ep *ep, int local)

{

    const struct sockaddr_in6 *addr = &ep->a.sin6;

    netsnmp_transport *t = NULL;

    netsnmp_udp_addr_pair     *addr_pair = NULL;

    int             rc = 0;

    int             socket_initialized = 0;

#ifdef NETSNMP_NO_LISTEN_SUPPORT

    if (local)

        return NULL;

#endif /* NETSNMP_NO_LISTEN_SUPPORT */

    if (addr == NULL || addr->sin6_family != AF_INET6)

        return NULL;

    t = netsnmp_transport_alloc();

    if (t == NULL)

        return NULL;

    DEBUGIF("netsnmp_tcp6") {

        char *str = netsnmp_tcp6_fmtaddr(NULL, addr,

                                         sizeof(struct sockaddr_in6));

        DEBUGMSGTL(("netsnmp_tcp6", "open %s %s\n", local ? "local" : "remote",

                    str));

        free(str);

    }

    addr_pair = calloc(1, sizeof(netsnmp_udp_addr_pair));

    if (addr_pair == NULL)

        goto err;

    t->data = addr_pair;

    t->data_length = sizeof(netsnmp_udp_addr_pair);

    memcpy(&addr_pair->remote_addr.sin6, addr, sizeof(struct sockaddr_in6));

    t->domain = netsnmp_TCPIPv6Domain;

    t->domain_length = OID_LENGTH(netsnmp_TCPIPv6Domain);

#ifndef NETSNMP_NO_SYSTEMD

    /*

     * Maybe the socket was already provided by systemd...

     */

    if (local) {

        t->sock = netsnmp_sd_find_inet_socket(PF_INET6, SOCK_STREAM, 1,

                ntohs(addr->sin6_port));

        if (t->sock >= 0)

            socket_initialized = 1;

    }

#endif

    if (!socket_initialized)

        t->sock = socket(PF_INET6, SOCK_STREAM, 0);

    if (!NETSNMP_IS_VALID_SOCKET(t->sock))

        goto err;

    t->flags = NETSNMP_TRANSPORT_FLAG_STREAM;

    /* for Linux VRF Traps we try to bind the iface if clientaddr is not set */

    if (local == 0 && ep) {

        rc = netsnmp_bindtodevice(t->sock, ep->iface);

        if (rc)

            DEBUGMSGTL(("netsnmp_tcp",

                        "VRF: Could not bind socket %" NETSNMP_FMT_SKT " to %s\n",

                        t->sock, ep->iface));

        else

            DEBUGMSGTL(("netsnmp_tcp",

                        "VRF: Bound socket %" NETSNMP_FMT_SKT " to %s\n",

                        t->sock, ep->iface));

    }

    if (local) {

#ifndef NETSNMP_NO_LISTEN_SUPPORT

        int opt = 1;

        /*

         * This session is intended as a server, so we must bind on to the

         * given IP address, which may include an interface address, or could

         * be INADDR_ANY, but certainly includes a port number.

         */

#ifdef IPV6_V6ONLY

        /* Try to restrict PF_INET6 socket to IPv6 communications only. */

        {

    int one=1;

    if (setsockopt(t->sock, IPPROTO_IPV6, IPV6_V6ONLY, (char *)&one,

                         sizeof(one)) != 0) {

      DEBUGMSGTL(("netsnmp_tcp6",

                        "couldn't set IPV6_V6ONLY to %d bytes: %s\n", one,

                        strerror(errno)));

    } 

  }

#endif

        t->flags |= NETSNMP_TRANSPORT_FLAG_LISTEN;

        t->local_length = sizeof(*addr);

        t->local = netsnmp_memdup(addr, sizeof(*addr));

        if (!t->local)

            goto err;

        /*

         * We should set SO_REUSEADDR too.  

         */

        setsockopt(t->sock, SOL_SOCKET, SO_REUSEADDR, (void *)&opt,

                   sizeof(opt));

        if (!socket_initialized) {

            rc = netsnmp_bindtodevice(t->sock, ep->iface);

            if (rc != 0) {

                DEBUGMSGTL(("netsnmp_tcp6", "failed to bind to iface %s: %s\n",

                            ep->iface, strerror(errno)));

                goto err;

            }

            rc = bind(t->sock, (const struct sockaddr *)addr, sizeof(*addr));

            if (rc != 0)

                goto err;

        }

        /*

         * Since we are going to be letting select() tell us when connections

         * are ready to be accept()ed, we need to make the socket n0n-blocking

         * to avoid the race condition described in W. R. Stevens, ``Unix

         * Network Programming Volume I Second Edition'', pp. 422--4, which

         * could otherwise wedge the agent.

         */

        if (netsnmp_set_non_blocking_mode(t->sock, TRUE) < 0)

            DEBUGMSGTL(("netsnmp_tcp6",

                        "couldn't set non-blocking mode on fd %" NETSNMP_FMT_SKT "\n",

                        t->sock));

        /*

         * Now sit here and wait for connections to arrive.  

         */

        if (!socket_initialized) {

            rc = listen(t->sock, NETSNMP_STREAM_QUEUE_LEN);

            if (rc != 0)

                goto err;

        }

        /*

         * no buffer size on listen socket - doesn't make sense

         */

#else /* NETSNMP_NO_LISTEN_SUPPORT */

        return NULL;

#endif /* NETSNMP_NO_LISTEN_SUPPORT */

    } else {

        t->remote_length = sizeof(*addr);

        t->remote = netsnmp_memdup(addr, sizeof(*addr));

        if (!t->remote)

            goto err;

        /*

         * This is a client-type session, so attempt to connect to the far

         * end.  We don't go non-blocking here because it's not obvious what

         * you'd then do if you tried to do snmp_sends before the connection

         * had completed.  So this can block.

         */

        rc = connect(t->sock, (const struct sockaddr *)addr, sizeof(*addr));

        DEBUGMSGTL(("netsnmp_tcp6", "connect returns %d\n", rc));

        if (rc < 0)

            goto err;

        netsnmp_set_tcp_nodelay(t->sock, 1);

        /*

         * Allow user to override the send and receive buffers. Default is

         * to use os default.  Don't worry too much about errors --

         * just plough on regardless.  

         */

        netsnmp_sock_buffer_set(t->sock, SO_SNDBUF, local, 0);

        netsnmp_sock_buffer_set(t->sock, SO_RCVBUF, local, 0);

    }

    /*

     * Message size is not limited by this transport (hence msgMaxSize

     * is equal to the maximum legal size of an SNMP message).  

     */

    t->msgMaxSize = SNMP_MAX_PACKET_LEN;

    t->f_recv     = netsnmp_tcpbase_recv;

    t->f_send     = netsnmp_tcpbase_send;

    t->f_close    = netsnmp_socketbase_close;

    t->f_accept   = netsnmp_tcp6_accept;

    t->f_setup_session = netsnmp_ipbase_session_init;

    t->f_fmtaddr  = netsnmp_tcp6_fmtaddr;

    t->f_get_taddr = netsnmp_ipv6_get_taddr;

    return t;

err:

    netsnmp_socketbase_close(t);

    netsnmp_transport_free(t);

    return NULL;

}

netsnmp_transport *

netsnmp_tcp6_create_tstring(const char *str, int local,

          const char *default_target)

{

    struct netsnmp_ep ep;

    if (netsnmp_sockaddr_in6_3(&ep, str, default_target)) {

        return netsnmp_tcp6_transport(&ep, local);

    } else {

        return NULL;

    }

}

/*

 * See:

 * 

 * http://www.ietf.org/internet-drafts/draft-ietf-ops-taddress-mib-01.txt

 * 

 * (or newer equivalent) for details of the TC which we are using for

 * the mapping here.  

 */

netsnmp_transport *

netsnmp_tcp6_create_ostring(const void *o, size_t o_len, int local)

{

    struct netsnmp_ep ep;

    memset(&ep, 0, sizeof(ep));

    if (netsnmp_ipv6_ostring_to_sockaddr(&ep.a.sin6, o, o_len))

        return netsnmp_tcp6_transport(&ep, local);

    return NULL;

}

void

netsnmp_tcpipv6_ctor(void)

{

    tcp6Domain.name = netsnmp_TCPIPv6Domain;

    tcp6Domain.name_length = OID_LENGTH(netsnmp_TCPIPv6Domain);

    tcp6Domain.f_create_from_tstring_new = netsnmp_tcp6_create_tstring;

    tcp6Domain.f_create_from_ostring     = netsnmp_tcp6_create_ostring;

    tcp6Domain.prefix = calloc(4, sizeof(char *));

    if (!tcp6Domain.prefix) {

        snmp_log(LOG_ERR, "calloc() failed - out of memory\n");

        return;

    }

    tcp6Domain.prefix[0] = "tcp6";

    tcp6Domain.prefix[1] = "tcpv6";

    tcp6Domain.prefix[2] = "tcpipv6";

    netsnmp_tdomain_register(&tcp6Domain);

}

#endif /* NETSNMP_TRANSPORT_TCPIPV6_DOMAIN */