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

#include <net-snmp/library/snmpAAL5PVCDomain.h>

#include <stdio.h>
#include <sys/types.h>
#include <ctype.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
#include <atm.h>

#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/tools.h>


const oid netsnmp_AAL5PVCDomain[10] = { NETSNMP_ENTERPRISE_MIB, 3, 3, 3 };
static netsnmp_tdomain aal5pvcDomain;


/*
 * Return a string representing the address in data, or else the "far end"
 * address if data is NULL.  
 */

static char *
netsnmp_aal5pvc_fmtaddr(netsnmp_transport *t, const void *data, int len)
{
    const struct sockaddr_atmpvc *to = NULL;

    if (data != NULL && len == sizeof(struct sockaddr_atmpvc)) {
        to = (const struct sockaddr_atmpvc *) data;
    } else if (t != NULL && t->data != NULL &&
               t->data_length == sizeof(struct sockaddr_atmpvc)) {
        to = (const struct sockaddr_atmpvc *) t->data;
    }
    if (to == NULL) {
        return strdup("AAL5 PVC: unknown");
    } else {
        char *tmp;

        if (asprintf(&tmp, "AAL5 PVC: %hd.%hd.%d", to->sap_addr.itf,
		     to->sap_addr.vpi, to->sap_addr.vci) < 0)
            tmp = NULL;
        return tmp;
    }
}

static void
netsnmp_aal5pvc_get_taddr(netsnmp_transport *t, void **addr, size_t *addr_len)
{
    struct sockaddr_atmpvc *sa = t->remote;
    unsigned char *p;

    *addr_len = 8;
    if (!(*addr = malloc(*addr_len)))
        return;
    p = *addr;
    p[0] = sa->sap_addr.itf >> 8;
    p[1] = sa->sap_addr.itf >> 0;
    p[2] = sa->sap_addr.vpi >> 8;
    p[3] = sa->sap_addr.vpi >> 0;
    p[4] = sa->sap_addr.vci >> 24;
    p[5] = sa->sap_addr.vci >> 16;
    p[6] = sa->sap_addr.vci >> 8;
    p[7] = sa->sap_addr.vci >> 0;
}

/*
 * You can write something into opaque that will subsequently get passed back 
 * to your send function if you like.  For instance, you might want to
 * remember where a PDU came from, so that you can send a reply there...  
 */

static int
netsnmp_aal5pvc_recv(netsnmp_transport *t, void *buf, int size,
		     void **opaque, int *olength)
{
    int rc = -1;

    if (t != NULL && t->sock >= 0) {
	while (rc < 0) {
	    rc = recvfrom(t->sock, buf, size, 0, NULL, NULL);
	    if (rc < 0 && errno != EINTR) {
		break;
	    }
	}

        if (rc >= 0) {
            DEBUGIF("netsnmp_aal5pvc") {
                char *str = netsnmp_aal5pvc_fmtaddr(t, NULL, 0);
                DEBUGMSGTL(("netsnmp_aal5pvc",
                            "recv on fd %d got %d bytes (from %s)\n", t->sock,
                            rc, str));
                free(str);
            }
        } else {
            DEBUGMSGTL(("netsnmp_aal5pvc", "recv on fd %d err %d (\"%s\")\n", 
			t->sock, errno, strerror(errno)));
        }
        *opaque = NULL;
        *olength = 0;
    }
    return rc;
}



static int
netsnmp_aal5pvc_send(netsnmp_transport *t, const void *buf, int size,
                     void **opaque, int *olength)
{
    int rc = -1;
    const struct sockaddr *to = NULL;

    if (opaque != NULL && *opaque != NULL &&
        *olength == sizeof(struct sockaddr_atmpvc)) {
        to = (const struct sockaddr *) (*opaque);
    } else if (t != NULL && t->data != NULL &&
               t->data_length == sizeof(struct sockaddr_atmpvc)) {
        to = (const struct sockaddr *) (t->data);
    }

    if (to != NULL && t != NULL && t->sock >= 0) {
        DEBUGIF("netsnmp_aal5pvc") {
            char *str = netsnmp_aal5pvc_fmtaddr(NULL, to,
                                                sizeof(struct sockaddr_atmpvc));
            DEBUGMSGTL(("netsnmp_aal5pvc",
                        "send %d bytes from %p to %s on fd %d\n",
                        size, buf, str, t->sock));
            free(str);
        }
	while (rc < 0) {
	    rc = sendto(t->sock, buf, size, 0, NULL, 0);
	    if (rc < 0 && errno != EINTR) {
		break;
	    }
	}
    }
    return rc;
}



static int
netsnmp_aal5pvc_close(netsnmp_transport *t)
{
    int rc = -1;

    if (t->sock >= 0) {
        DEBUGMSGTL(("netsnmp_aal5pvc", "close fd %d\n", t->sock));
#ifndef HAVE_CLOSESOCKET
        rc = close(t->sock);
#else
        rc = closesocket(t->sock);
#endif
        t->sock = -1;
    }
    return rc;
}



/*
 * Open an AAL5 PVC transport for SNMP.  Local is TRUE if addr is the local 
 * NSAP to bind to (i.e. this is a server-type session); otherwise addr is 
 * the remote NSAP to send things to.  
 */

netsnmp_transport *
netsnmp_aal5pvc_transport(const struct sockaddr_atmpvc *addr, int local)
{
    netsnmp_transport *t = NULL;

#ifdef NETSNMP_NO_LISTEN_SUPPORT
    if (local)
        return NULL;
#endif /* NETSNMP_NO_LISTEN_SUPPORT */

    if (addr == NULL || addr->sap_family != AF_ATMPVC) {
        return NULL;
    }

    t = SNMP_MALLOC_TYPEDEF(netsnmp_transport);
    if (t == NULL) {
        return NULL;
    }

    DEBUGIF("netsnmp_aal5pvc") {
        char *str = netsnmp_aal5pvc_fmtaddr(NULL, addr,
                                            sizeof(struct sockaddr_atmpvc));
        DEBUGMSGTL(("netsnmp_aal5pvc", "open %s %s\n",
                    local ? "local" : "remote", str));
        free(str);
    }

    t->domain = netsnmp_AAL5PVCDomain;
    t->domain_length =
        sizeof(netsnmp_AAL5PVCDomain) / sizeof(netsnmp_AAL5PVCDomain[0]);

    t->sock = socket(PF_ATMPVC, SOCK_DGRAM, 0);
    if (t->sock < 0) {
        DEBUGMSGTL(("netsnmp_aal5pvc","socket failed (%s)\n",strerror(errno)));
        netsnmp_transport_free(t);
        return NULL;
    }
    DEBUGMSGTL(("netsnmp_aal5pvc", "fd %d opened\n", t->sock));

    {
        /*
         * Set up the QOS parameters.
         */

        struct atm_qos qos = { };
        qos.aal = ATM_AAL5;
        qos.rxtp.traffic_class = ATM_UBR;
        qos.rxtp.max_sdu = SNMP_MAX_LEN;    /*  Hmm -- this is a bit small?  */
        qos.txtp = qos.rxtp;

        if (setsockopt(t->sock, SOL_ATM, SO_ATMQOS, &qos, sizeof(qos)) < 0) {
            DEBUGMSGTL(("netsnmp_aal5pvc", "setsockopt failed (%s)\n",
                        strerror(errno)));
            netsnmp_aal5pvc_close(t);
            netsnmp_transport_free(t);
            return NULL;
        }
    }

    if (local) {
#ifndef NETSNMP_NO_LISTEN_SUPPORT
        t->local_length = sizeof(*addr);
        t->local = netsnmp_memdup(addr, sizeof(*addr));
        if (t->local == NULL) {
            netsnmp_transport_free(t);
            return NULL;
        }

        if (bind(t->sock, (const struct sockaddr *)addr,
                 sizeof(struct sockaddr_atmpvc)) < 0) {
            DEBUGMSGTL(("netsnmp_aal5pvc", "bind failed (%s)\n",
                        strerror(errno)));
            netsnmp_aal5pvc_close(t);
            netsnmp_transport_free(t);
            return NULL;
        }
#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 == NULL) {
            netsnmp_transport_free(t);
            return NULL;
        }

        if (connect(t->sock, (const struct sockaddr *)addr,
                    sizeof(struct sockaddr_atmpvc)) < 0) {
            DEBUGMSGTL(("netsnmp_aal5pvc", "connect failed (%s)\n",
                        strerror(errno)));
            netsnmp_aal5pvc_close(t);
            netsnmp_transport_free(t);
            return NULL;
        }
    }

    t->data = malloc(sizeof(struct sockaddr_atmpvc));
    if (t->data == NULL) {
        netsnmp_transport_free(t);
        return NULL;
    }
    memcpy(t->data, addr, sizeof(struct sockaddr_atmpvc));
    t->data_length = sizeof(struct sockaddr_atmpvc);

    /*
     * 16-bit length field in the trailer, no headers.  
     */

    t->msgMaxSize = 0xffff;
    t->f_recv     = netsnmp_aal5pvc_recv;
    t->f_send     = netsnmp_aal5pvc_send;
    t->f_close    = netsnmp_aal5pvc_close;
    t->f_accept   = NULL;
    t->f_fmtaddr  = netsnmp_aal5pvc_fmtaddr;
    t->f_get_taddr = netsnmp_aal5pvc_get_taddr;

    return t;
}



netsnmp_transport *
netsnmp_aal5pvc_create_tstring(const char *str, int local,
			       const char *default_target)
{
    struct sockaddr_atmpvc addr;

    if (str == NULL || *str == '\0')
	str = default_target;

    if (str != NULL) {
        addr.sap_family = AF_ATMPVC;

        if (sscanf(str, "%hd.%hd.%d", &(addr.sap_addr.itf),
                   &(addr.sap_addr.vpi), &(addr.sap_addr.vci)) == 3) {
            return netsnmp_aal5pvc_transport(&addr, local);
        } else if (sscanf(str, "%hd.%d", &(addr.sap_addr.vpi),
                          &(addr.sap_addr.vci)) == 2) {
            addr.sap_addr.itf = 0;
            return netsnmp_aal5pvc_transport(&addr, local);
        } else if (sscanf(str, "%d", &(addr.sap_addr.vci)) == 1) {
            addr.sap_addr.itf = 0;
            addr.sap_addr.vpi = 0;
            return netsnmp_aal5pvc_transport(&addr, local);
        } else {
            return NULL;
        }
    } else {
        return NULL;
    }
}

static int netsnmp_aal5pvc_ostring_to_sockaddr(struct sockaddr_atmpvc *sa,
                                               const void *o, size_t o_len)
{
    const unsigned char *p = o;

    if (o_len != 8)
        return 0;

    memset(sa, 0, sizeof(*sa));
    sa->sap_family = AF_ATMPVC;
    sa->sap_addr.itf = (p[0] << 8) + (p[1] << 0);
    sa->sap_addr.vpi = (p[2] << 8) + (p[3] << 0);
    sa->sap_addr.vci = (p[4] << 24) + (p[5] << 16) + (p[6] << 8) + (p[7] << 0);
    return 1;
}

netsnmp_transport *
netsnmp_aal5pvc_create_ostring(const void *o, size_t o_len, int local)
{
    struct sockaddr_atmpvc sa;

    if (netsnmp_aal5pvc_ostring_to_sockaddr(&sa, o, o_len))
        return netsnmp_aal5pvc_transport(&sa, local);
    return NULL;
}



void
netsnmp_aal5pvc_ctor(void)
{
    aal5pvcDomain.name = netsnmp_AAL5PVCDomain;
    aal5pvcDomain.name_length = OID_LENGTH(netsnmp_AAL5PVCDomain);
    aal5pvcDomain.prefix = calloc(3, sizeof(char *));
    if (!aal5pvcDomain.prefix) {
        snmp_log(LOG_ERR, "calloc() failed - out of memory\n");
        return;
    }
    aal5pvcDomain.prefix[0] = "aal5pvc";
    aal5pvcDomain.prefix[1] = "pvc";

    aal5pvcDomain.f_create_from_tstring_new = netsnmp_aal5pvc_create_tstring;
    aal5pvcDomain.f_create_from_ostring     = netsnmp_aal5pvc_create_ostring;

    netsnmp_tdomain_register(&aal5pvcDomain);
}
