block.h

一个阻断tcp连接的程序。可以实时的抓包并且经过分析后阻断已建立的tcp联接。

#ifndef _BLOCK_H
#define _BLOCK_H

#ifdef __cplusplus
extern   "C" {
#endif

#include <stdio.h>
#include <pthread.h>

#include <linux/types.h>
#include <syslog.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <net/ethernet.h>
#include <net/if_arp.h>
#include <linux/ppp_defs.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>


#define udpLen 48

/*// __BIG_ENDIAN
struct rtp_g723{
    u_int16_t ver:2;
    u_int16_t pad:1;
    u_int16_t ext:1;
    u_int16_t csrc_count:4;

    u_int16_t mark:1;
    u_int16_t payload:7;

    u_int16_t seq;
    u_int32_t stamp;

    u_int32_t ssrc;
};*/

//__LITTLE_ENDIAN
struct rtp_g723{
    u_int16_t csrc_count:4;
    u_int16_t ext:1;
    u_int16_t pad:1;
    u_int16_t ver:2;

    u_int16_t payload:7;
    u_int16_t mark:1;

    u_int16_t seq;
    u_int32_t stamp;

    u_int32_t ssrc;
};



typedef struct PPPoE_PacketStruct {
    struct ethhdr ethHdr;	/* Ethernet header */

    unsigned int ver:4;		/* PPPoE Version (must be 1) */
    unsigned int type:4;	/* PPPoE Type (must be 1) */

    u_char  code;	/* PPPoE code */
    u_short session;	/* PPPoE session */
    u_short length;	/* Payload length */
    u_short p_proto;
} PPPoE_Packet;


struct pseudo_hdr { /* See RFC 793 Pseudo Header */
    u_long saddr, daddr;/* source and dest address */
    u_char mbz, ptcl;	/* zero and protocol */
    u_short tcpl;	/* tcp length */
};


struct cksum {
    struct pseudo_hdr pseudo;
    struct tcphdr tcp;
};


struct cksum_udp {
    struct pseudo_hdr pseudo;
    struct udphdr udp;
    struct rtp_g723 rtp;
    u_char data[udpLen];
};

inline u_short in_cksum(u_short *addr, int len);
static void InitTcp();
void MakeTcp();
void MakePoe();
int BlockPoeTcp();
int BlockEthTcp();


#ifdef __cplusplus
}
#endif
#endif