ethernet.c

Bacnet protocol stack for linux

/**************************************************************************
*
* Copyright (C) 2005 Steve Karg <[e-mail]>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*********************************************************************/

#include <stdint.h>     /* for standard integer types uint8_t etc. */
#include <stdbool.h>    /* for the standard bool type. */
#include <stdio.h>      /* for the standard bool type. */
#include <stdlib.h>     /* for the standard bool type. */
#include <rttarget.h>
#include <rtk32.h>
#include <clock.h>
#include <socket.h>
#include <windows.h>
#include "ethernet.h"
#include "bacdcode.h"
#include "npdu.h"

/* commonly used comparison address for ethernet */
uint8_t Ethernet_Broadcast[MAX_MAC_LEN] =
    { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
/* commonly used empty address for ethernet quick compare */
uint8_t Ethernet_Empty_MAC[MAX_MAC_LEN] = { 0, 0, 0, 0, 0, 0 };

/* my local device data - MAC address */
uint8_t Ethernet_MAC_Address[MAX_MAC_LEN] = { 0, 0, 0, 0, 0, 0 };

static SOCKET Ethernet_Socket = -1;
/* used for binding 802.2 */
static struct sockaddr Ethernet_Address = { 0 };

bool ethernet_valid(
    void)
{
    return (Ethernet_Socket != -1);
}

void ethernet_cleanup(
    void)
{
    if (ethernet_valid())
        closesocket(Ethernet_Socket);
    Ethernet_Socket = -1;

    return;
}

bool ethernet_init(
    char *interface_name)
{
    int value = 1;

    (void) interface_name;
    /* setup the socket */
    Ethernet_Socket = socket(AF_INET, SOCK_RAW, 0);
    /*Ethernet_Socket = socket(AF_INET, SOCK_STREAM, 0); */
    if (Ethernet_Socket < 0)
        fprintf(stderr, "ethernet: failed to bind to socket!\r\n");
    Ethernet_Address.sa_family = AF_INET;
    memset(Ethernet_Address.sa_data, 0, sizeof(Ethernet_Address.sa_data));
    if (bind(Ethernet_Socket, &Ethernet_Address,
            sizeof(Ethernet_Address)) == SOCKET_ERROR)
        fprintf(stderr, "ethernet: failed to bind to socket!\r\n");
    /*setsockopt(Ethernet_Socket,SOL_SOCKET,SO_802_2,(char *)&value,sizeof(value));     */

    return ethernet_valid();
}

/* function to send a packet out the 802.2 socket */
/* returns bytes sent on success, negative number on failure */
int ethernet_send(
    BACNET_ADDRESS * dest,      /* destination address */
    BACNET_ADDRESS * src,       /* source address */
    BACNET_NPDU_DATA * npdu_data,       /* network information */
    uint8_t * pdu,      /* any data to be sent - may be null */
    unsigned pdu_len)
{       /* number of bytes of data */
    int bytes = 0;
    uint8_t mtu[MAX_MPDU] = { 0 };
    int mtu_len = 0;
    int i = 0;

    (void) npdu_data;
    /* don't waste time if the socket is not valid */
    if (Ethernet_Socket < 0) {
        fprintf(stderr, "ethernet: 802.2 socket is invalid!\n");
        return -1;
    }
    /* load destination ethernet MAC address */
    if (dest->mac_len == 6) {
        for (i = 0; i < 6; i++) {
            mtu[mtu_len] = dest->mac[i];
            mtu_len++;
        }
    } else {
        fprintf(stderr, "ethernet: invalid destination MAC address!\n");
        return -2;
    }

    /* load source ethernet MAC address */
    if (src->mac_len == 6) {
        for (i = 0; i < 6; i++) {
            mtu[mtu_len] = src->mac[i];
            mtu_len++;
        }
    } else {
        fprintf(stderr, "ethernet: invalid source MAC address!\n");
        return -3;
    }
    if ((14 + 3 + pdu_len) > MAX_MPDU) {
        fprintf(stderr, "ethernet: PDU is too big to send!\n");
        return -4;
    }
    /* packet length */
    mtu_len += encode_unsigned16(&mtu[12], 3 /*DSAP,SSAP,LLC */  + pdu_len);
    /* Logical PDU portion */
    mtu[mtu_len++] = 0x82;      /* DSAP for BACnet */
    mtu[mtu_len++] = 0x82;      /* SSAP for BACnet */
    mtu[mtu_len++] = 0x03;      /* Control byte in header */
    mtu_len = 17;
    if ((mtu_len + pdu_len) > MAX_MPDU) {
        fprintf(stderr, "ethernet: PDU is too big to send!\n");
        return -4;
    }
    memcpy(&mtu[mtu_len], pdu, pdu_len);
    mtu_len += pdu_len;
    /* packet length - only the logical portion, not the address */
    encode_unsigned16(&mtu[12], 3 + pdu_len);

    /* Send the packet */
    bytes = send(Ethernet_Socket, (const char *) &mtu, mtu_len, 0);
    /* did it get sent? */
    if (bytes < 0)
        fprintf(stderr, "ethernet: Error sending packet: %s\n",
            strerror(errno));

    return bytes;
}

/* function to send a packet out the 802.2 socket */
/* returns bytes sent on success, negative number on failure */
int ethernet_send_pdu(
    BACNET_ADDRESS * dest,      /* destination address */
    BACNET_NPDU_DATA * npdu_data,       /* network information */
    uint8_t * pdu,      /* any data to be sent - may be null */
    unsigned pdu_len)
{       /* number of bytes of data */
    int i = 0;  /* counter */
    BACNET_ADDRESS src = { 0 }; /* source address */

    for (i = 0; i < 6; i++) {
        src.mac[i] = Ethernet_MAC_Address[i];
        src.mac_len++;
    }

    /* FIXME: npdu_data? */
    /* function to send a packet out the 802.2 socket */
    /* returns 1 on success, 0 on failure */
    return ethernet_send(dest,  /* destination address */
        &src,   /* source address */
        npdu_data, pdu, /* any data to be sent - may be null */
        pdu_len);       /* number of bytes of data */
}

/* receives an 802.2 framed packet */
/* returns the number of octets in the PDU, or zero on failure */
uint16_t ethernet_receive(
    BACNET_ADDRESS * src,       /* source address */
    uint8_t * pdu,      /* PDU data */
    uint16_t max_pdu,   /* amount of space available in the PDU  */
    unsigned timeout)
{       /* number of milliseconds to wait for a packet */
    int received_bytes;
    uint8_t buf[MAX_MPDU] = { 0 };      /* data */
    uint16_t pdu_len = 0;       /* return value */
    fd_set read_fds;
    int max;
    struct timeval select_timeout;

    /* Make sure the socket is open */
    if (Ethernet_Socket <= 0)
        return 0;

    /* we could just use a non-blocking socket, but that consumes all
       the CPU time.  We can use a timeout; it is only supported as
       a select. */
    if (timeout >= 1000) {
        select_timeout.tv_sec = timeout / 1000;
        select_timeout.tv_usec =
            1000 * (timeout - select_timeout.tv_sec * 1000);
    } else {
        select_timeout.tv_sec = 0;
        select_timeout.tv_usec = 1000 * timeout;
    }
    FD_ZERO(&read_fds);
    FD_SET(Ethernet_Socket, &read_fds);
    max = Ethernet_Socket;

    if (select(max + 1, &read_fds, NULL, NULL, &select_timeout) > 0)
        received_bytes = recv(Ethernet_Socket, (char *) &buf[0], MAX_MPDU, 0);
    else
        return 0;

    /* See if there is a problem */
    if (received_bytes < 0) {
        /* EAGAIN Non-blocking I/O has been selected  */
        /* using O_NONBLOCK and no data */
        /* was immediately available for reading. */
        if (errno != EAGAIN)
            fprintf(stderr, "ethernet: Read error in receiving packet: %s\n",
                strerror(errno));
        return 0;
    }

    if (received_bytes == 0)
        return 0;

    /* the signature of an 802.2 BACnet packet */
    if ((buf[14] != 0x82) && (buf[15] != 0x82)) {
        /*fprintf(stderr,"ethernet: Non-BACnet packet\n"); */
        return 0;
    }
    /* copy the source address */
    src->mac_len = 6;
    memmove(src->mac, &buf[6], 6);

    /* check destination address for when */
    /* the Ethernet card is in promiscious mode */
    if ((memcmp(&buf[0], Ethernet_MAC_Address, 6) != 0)
        && (memcmp(&buf[0], Ethernet_Broadcast, 6) != 0)) {
        /*fprintf(stderr, "ethernet: This packet isn't for us\n"); */
        return 0;
    }

    (void) decode_unsigned16(&buf[12], &pdu_len);
    pdu_len -= 3 /* DSAP, SSAP, LLC Control */ ;
    /* copy the buffer into the PDU */
    if (pdu_len < max_pdu)
        memmove(&pdu[0], &buf[17], pdu_len);
    /* ignore packets that are too large */
    /* client should check my max apdu first */
    else
        pdu_len = 0;

    return pdu_len;
}

void ethernet_get_my_address(
    BACNET_ADDRESS * my_address)
{
    int i = 0;

    my_address->mac_len = 0;
    for (i = 0; i < 6; i++) {
        my_address->mac[i] = Ethernet_MAC_Address[i];
        my_address->mac_len++;
    }
    my_address->net = 0;        /* local only, no routing */
    my_address->len = 0;
    for (i = 0; i < MAX_MAC_LEN; i++) {
        my_address->adr[i] = 0;
    }

    return;
}

void ethernet_set_my_address(
    BACNET_ADDRESS * my_address)
{
    int i = 0;

    for (i = 0; i < 6; i++) {
        Ethernet_MAC_Address[i] = my_address->mac[i];
    }

    return;
}

void ethernet_get_broadcast_address(
    BACNET_ADDRESS * dest)
{       /* destination address */
    int i = 0;  /* counter */

    if (dest) {
        for (i = 0; i < 6; i++) {
            dest->mac[i] = Ethernet_Broadcast[i];
        }
        dest->mac_len = 6;
        dest->net = BACNET_BROADCAST_NETWORK;
        dest->len = 0;  /* denotes broadcast address  */
        for (i = 0; i < MAX_MAC_LEN; i++) {
            dest->adr[i] = 0;
        }
    }

    return;
}

void ethernet_debug_address(
    const char *info,
    BACNET_ADDRESS * dest)
{
    int i = 0;  /* counter */

    if (info)
        fprintf(stderr, "%s", info);
    if (dest) {
        fprintf(stderr, "Address:\n");
        fprintf(stderr, "  MAC Length=%d\n", dest->mac_len);
        fprintf(stderr, "  MAC Address=");
        for (i = 0; i < MAX_MAC_LEN; i++) {
            fprintf(stderr, "%02X ", (unsigned) dest->mac[i]);
        }
        fprintf(stderr, "\n");
        fprintf(stderr, "  Net=%hu\n", dest->net);
        fprintf(stderr, "  Len=%d\n", dest->len);
        fprintf(stderr, "  Adr=");
        for (i = 0; i < MAX_MAC_LEN; i++) {
            fprintf(stderr, "%02X ", (unsigned) dest->adr[i]);
        }
        fprintf(stderr, "\n");
    }

    return;
}