Read/write raw packets in C in Linux

raw_packet_read_write.c

//Based on https://github.com/cnlohr/lamenet/blob/master/librawp.c

#include <stdio.h>
#include <arpa/inet.h>
#include <string.h>
#include <linux/if_packet.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <pthread.h>
#include <unistd.h>

int sock_raw;


void * ReceiveThread()
{
	printf( "Preparing to receive from socket %d\n", sock_raw );
	while(1)
	{
		uint8_t rbuff[8192];
		int rx = recv( sock_raw, rbuff, sizeof( rbuff ), 0 );
		printf( "RX: %4d:", rx );
		int i;
		for( i = 0; i < 20; i++ )
		{
			printf( "%02x ", rbuff[i] );
		}
		printf( "\n" );
	}
	
}

int main()
{
	const char * interface = "enp10s0";

	struct ifreq ifr;
	struct sockaddr_ll sa;
	size_t if_name_len=strlen(interface);
	int ss = 0;

	sock_raw = socket( PF_PACKET, SOCK_RAW, htons(ETH_P_ALL) );
	if( sock_raw < 0 )
	{
		fprintf( stderr, "Error: Can't open socket.\n" );
		return -1;
	}
	if (if_name_len<sizeof(ifr.ifr_name)) {
		memcpy(ifr.ifr_name,interface,if_name_len);
		ifr.ifr_name[if_name_len]=0;
	
	}
	else
	{
		close( sock_raw );
		return -1;
	}
	ioctl( sock_raw, SIOCGIFINDEX, &ifr );


	memset( &sa, 0, sizeof( sa ) );
	sa.sll_family=PF_PACKET;
	sa.sll_protocol = 0x0000;
	sa.sll_ifindex = ifr.ifr_ifindex;
	sa.sll_hatype = 0;
	sa.sll_pkttype = PACKET_HOST;

	// Not sure why, this is required for receiving on some systems.
	bind( sock_raw,(const struct sockaddr *)&sa, sizeof( sa ) );
	ss = setsockopt( sock_raw, SOL_SOCKET, SO_BINDTODEVICE, interface, strlen(interface) );


	pthread_t thd;
	pthread_create( &thd, 0, ReceiveThread, 0 );


	if( ss < 0 )
	{
		close( sock_raw );
		return -1;
	}
	
	while(1)
	{
		struct sockaddr_ll socket_address;
		uint8_t my_packet[] = {
			0x81, 0x23, 0x45, 0x67, 0x89, 0xac, //dst mac
			0x81, 0x23, 0x45, 0x67, 0x89, 0xab, //src mac
			10,
			0x00, 0x00, 0x00, 0x00, 0x0,
			0x00, 0x00, 0x00, 0x00, 0x0,
		};

	
		// Setup sending address for packet.
		socket_address.sll_ifindex = ifr.ifr_ifindex;
		socket_address.sll_halen = ETH_ALEN;
		memcpy( socket_address.sll_addr, my_packet+6, 6 );

		if (sendto(sock_raw, my_packet, sizeof(my_packet), 0, (struct sockaddr*)&socket_address, sizeof(struct sockaddr_ll)) < 0)
			printf("Send failed\n");
			
		sleep(1);
	}
}