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ethernet_drv.c
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Anders Blomdell / LabComm
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ethernet_drv.c 6.90 KiB
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/if_ether.h>
#include <linux/if_packet.h>
#include <linux/if_arp.h>
#include <netinet/in.h>
#include "ethernet_drv.h"
#include "display.h"
/** LOCAL FUNCTIONS **/
/* local type for the ethernet interface */
struct eth_int_t
{
unsigned char mac_adr[ETH_ALEN]; /* MAC address */
int socket_id; /* socket file descriptor */
int index; /* index of the eth interface */
unsigned char validity;
};
/***
Open an Ethernet Raw packet connection
***/
struct eth_int_t* eth_open(const char* eth_int_name)
{
struct eth_int_t* tmp_eth = NULL; /* pointer to ethernet interface struct */
struct ifreq ifr; /* struct used by ioctl function */
/* TO-DO: check if a ethernet socket has already been created for eth_int_name interface */
/* Ethernet interface name pointer valid ? */
if (NULL == eth_int_name)
{
errno = EINVAL;
DISPLAY_ERR("Input parameter NULL");
}
else
{
/* allocate memory for the Ethernet Interface */
tmp_eth = (struct eth_int_t*)malloc(sizeof(struct eth_int_t));
if (NULL == tmp_eth)
{
DISPLAY_ERR("Error allocating memory!");
}
else
{
/* creates a Packet Socket, raw delivery, accept all protocol */
tmp_eth->socket_id = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
if (-1 == tmp_eth->socket_id) /* error occurred during socket creation ? */
{
free(tmp_eth); /* deallocate the memory */
tmp_eth = NULL;
DISPLAY_ERR("Error in creating socket");
}
else
{
/* retrieve the Ethernet card MAC address */
strcpy(ifr.ifr_name, eth_int_name);
if (ioctl(tmp_eth->socket_id, SIOCGIFHWADDR, &ifr) == -1) /* error during the retrieve of MAC address ? */
{
close(tmp_eth->socket_id); /* close the socket */
free(tmp_eth); /* deallocate the memory */
tmp_eth = NULL;
DISPLAY_ERR("ioctl error SIOCGIFHWADDR"); }
else
{
/* copy the MAC address into the eth interface struct */
memcpy(tmp_eth->mac_adr, ifr.ifr_hwaddr.sa_data, ETH_ALEN);
/*retrieve the Ethernet interface index*/
if (ioctl(tmp_eth->socket_id, SIOCGIFINDEX, &ifr) == -1)/* error during the retrieve of index */
{
close(tmp_eth->socket_id); /* close the socket */
free(tmp_eth); /* deallocate the memory */
tmp_eth = NULL;
DISPLAY_ERR("ioctl error SIOCGIFINDEX");
}
else
{
/* copy the interface index into the eth interface struct */
tmp_eth->index = ifr.ifr_ifindex;
printf("Successfully got our MAC address: %02X:%02X:%02X:%02X:%02X:%02X\n",
tmp_eth->mac_adr[0],tmp_eth->mac_adr[1],tmp_eth->mac_adr[2],tmp_eth->mac_adr[3],tmp_eth->mac_adr[4],tmp_eth->mac_adr[5]);
printf("Successfully got interface index for %s: %i\n",eth_int_name, tmp_eth->index);
}
}
}
}
}
return(tmp_eth);
}
/***
Close the Ethernet Raw packet connection
***/
int eth_close(struct eth_int_t* eth_int)
{
int ret = 0;
/* Ethernet interface pointer valid ? */
if (NULL == eth_int)
{
ret = -1;
errno = EINVAL;
DISPLAY_ERR("Input parameter NULL");
}
else
{
if (-1 == close(eth_int->socket_id)) /* error during the closure of the socket ? */
{
ret = -1;
DISPLAY_ERR("Socket closure error");
}
else
{
free(eth_int); /* deallocate the memory */
eth_int = NULL;
}
}
return(ret);
}
/***
Returns the MAC address of the Ethernet Interface
***/
int eth_getMACadr(const struct eth_int_t* eth_int, unsigned char* mac_adr)
{
int ret = 0;
if ((NULL == eth_int) || (NULL == mac_adr)) /* Input parameters valid ? */
{
ret = -1;
errno = EINVAL; DISPLAY_ERR("Input parameter(s) NULL");
}
else
{
/* TO-DO: introduce a validity flag to be check before accessing to eth_int (better a crc) */
memcpy(mac_adr, eth_int->mac_adr, ETH_ALEN);
}
return(ret);
}
/***
send a complete Ethernet Raw Packet
***/
int eth_send(const struct eth_int_t* eth_int, const unsigned char* eth_frame, unsigned short length)
{
struct ethhdr *eth_header = NULL; /* Pointer to Ethernet frame header (Dest,Source,Type) */
struct sockaddr_ll socket_address;
int ret;
if ((NULL == eth_int) || (NULL == eth_frame))
{
ret = -1;
errno = EINVAL;
DISPLAY_ERR("Input parameter(s) Null!");
}
else
{
eth_header = (struct ethhdr*)eth_frame;
/*prepare sockaddr_ll (address structure for PACKET_SOCKET) */
socket_address.sll_family = AF_PACKET;
socket_address.sll_protocol = htons(ETH_P_IP); /* Physical layer protocol */
socket_address.sll_ifindex = eth_int->index; /* Ethernet Interface index */
socket_address.sll_hatype = ARPHRD_ETHER; /* ARP hardware identifier: Ethernet */
socket_address.sll_pkttype = PACKET_OTHERHOST; /* Packet type: Another host */
socket_address.sll_halen = ETH_ALEN; /* Length of the MAC address */
socket_address.sll_addr[0] = eth_header->h_dest[0];
socket_address.sll_addr[1] = eth_header->h_dest[1];
socket_address.sll_addr[2] = eth_header->h_dest[2];
socket_address.sll_addr[3] = eth_header->h_dest[3];
socket_address.sll_addr[4] = eth_header->h_dest[4];
socket_address.sll_addr[5] = eth_header->h_dest[5];
socket_address.sll_addr[6] = 0x00; /* not used */
socket_address.sll_addr[7] = 0x00; /* not used */
/*send the Ethernet frame */
ret = sendto(eth_int->socket_id, eth_frame, length, 0, (struct sockaddr*)&socket_address, sizeof(socket_address));
if (ret == -1) /* error during the trasmission of the Ethernet frame ? */
{
DISPLAY_ERR("sendto error!");
}
}
return(ret);
}
/***
receive a complete Ethernet Raw Packet
***/
int eth_receive (const struct eth_int_t* eth_int, unsigned char* eth_frame, unsigned short length)
{
int ret;
if ((NULL == eth_int) || (NULL == eth_frame))
{
ret = -1;
errno = EINVAL;
DISPLAY_ERR("Input parameter(s) Null!");
}
else {
/*Wait for incoming packet...*/
ret = recvfrom(eth_int->socket_id, (void*)eth_frame, length, 0, NULL, NULL);
if (ret == -1) /* error during the reception of the Ethernet frame ? */
{
DISPLAY_ERR("recvfrom error!");
}
}
return(ret);
}