一、TCP socket ipv6与ipv4的区别
服务器端源代码如下：
1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <errno.h> 4 #include <string.h> 5 #include <sys/types.h> 6 #include <netinet/in.h> 7 #include <sys/socket.h> 8 #include <sys/wait.h> 9 #include <unistd.h> 10 #include <arpa/inet.h> 11 #define MAXBUF 1024 12 int main(int argc, char **argv) 13 { 14 int sockfd, new_fd; 15 socklen_t len; 16 17 /* struct sockaddr_in my_addr, their_addr; */ // IPv4 18 struct sockaddr_in6 my_addr, their_addr; // IPv6 19 20 unsigned int myport, lisnum; 21 char buf[MAXBUF + 1]; 22 23 if (argv[1]) 24 myport = atoi(argv[1]); 25 else 26 myport = 7838; 27 28 if (argv[2]) 29 lisnum = atoi(argv[2]); 30 else 31 lisnum = 2; 32 33 /* if ((sockfd = socket(PF_INET, SOCK_STREAM, 0)) == -1) { */ // IPv4 34 if ((sockfd = socket(PF_INET6, SOCK_STREAM, 0)) == -1) { // IPv6 35 perror("socket"); 36 exit(1); 37 } else 38 printf("socket created/n"); 39 40 bzero(&my_addr, sizeof(my_addr)); 41 /* my_addr.sin_family = PF_INET; */ // IPv4 42 my_addr.sin6_family = PF_INET6; // IPv6 43 /* my_addr.sin_port = htons(myport); */ // IPv4 44 my_addr.sin6_port = htons(myport); // IPv6 45 if (argv[3]) 46 /* my_addr.sin_addr.s_addr = inet_addr(argv[3]); */ // IPv4 47 inet_pton(AF_INET6, argv[3], &my_addr.sin6_addr); // IPv6 48 else 49 /* my_addr.sin_addr.s_addr = INADDR_ANY; */ // IPv4 50 my_addr.sin6_addr = in6addr_any; // IPv6 51 52 /* if (bind(sockfd, (struct sockaddr *) &my_addr, sizeof(struct sockaddr)) */ // IPv4 53 if (bind(sockfd, (struct sockaddr *) &my_addr, sizeof(struct sockaddr_in6)) // IPv6 54 == -1) { 55 perror("bind"); 56 exit(1); 57 } else 58 printf("binded/n"); 59 60 if (listen(sockfd, lisnum) == -1) { 61 perror("listen"); 62 exit(1); 63 } else 64 printf("begin listen/n"); 65 66 while (1) { 67 len = sizeof(struct sockaddr); 68 if ((new_fd = 69 accept(sockfd, (struct sockaddr *) &their_addr, 70 &len)) == -1) { 71 perror("accept"); 72 exit(errno); 73 } else 74 printf("server: got connection from %s, port %d, socket %d/n", 75 /* inet_ntoa(their_addr.sin_addr), */ // IPv4 76 inet_ntop(AF_INET6, &their_addr.sin6_addr, buf, sizeof(buf)), // IPv6 77 /* ntohs(their_addr.sin_port), new_fd); */ // IPv4 78 their_addr.sin6_port, new_fd); // IPv6 79 80 /* 开始处理每个新连接上的数据收发 */ 81 bzero(buf, MAXBUF + 1); 82 strcpy(buf, 83 "这是在连接建立成功后向客户端发送的第一个消息/n只能向new_fd这个用accept函数新建立的socket发消息，不能向sockfd这个监听socket发送消息，监听socket不能用来接收或发送消息/n"); 84 /* 发消息给客户端 */ 85 len = send(new_fd, buf, strlen(buf), 0); 86 if (len < 0) { 87 printf 88 ("消息'%s'发送失败！错误代码是%d，错误信息是'%s'/n", 89 buf, errno, strerror(errno)); 90 } else 91 printf("消息'%s'发送成功，共发送了%d个字节！/n", 92 buf, len); 93 94 bzero(buf, MAXBUF + 1); 95 /* 接收客户端的消息 */ 96 len = recv(new_fd, buf, MAXBUF, 0); 97 if (len > 0) 98 printf("接收消息成功:'%s'，共%d个字节的数据/n", 99 buf, len); 100 else 101 printf 102 ("消息接收失败！错误代码是%d，错误信息是'%s'/n", 103 errno, strerror(errno)); 104 /* 处理每个新连接上的数据收发结束 */ 105 } 106 107 close(sockfd); 108 return 0; 109 }
每行程序后面的 “//IPv4” 表示这行代码是在IPv4网络里用的
而“//IPv6” 表示这行代码是在IPv6网络里用的，比较一下，会很容易看到差别的。
客户端源代码如下：
1 #include <stdio.h> 2 #include <string.h> 3 #include <errno.h> 4 #include <sys/socket.h> 5 #include <resolv.h> 6 #include <stdlib.h> 7 #include <netinet/in.h> 8 #include <arpa/inet.h> 9 #include <unistd.h> 10 #define MAXBUF 1024 11 int main(int argc, char **argv) 12 { 13 int sockfd, len; 14 /* struct sockaddr_in dest; */ // IPv4 15 struct sockaddr_in6 dest; // IPv6 16 char buffer[MAXBUF + 1]; 17 18 if (argc != 3) { 19 printf 20 ("参数格式错误！正确用法如下：/n/t/t%s IP地址 端口/n/t比如:/t%s 127.0.0.1 80/n此程序用来从某个 IP 地址的服务器某个端口接收最多 MAXBUF 个字节的消息", 21 argv[0], argv[0]); 22 exit(0); 23 } 24 /* 创建一个 socket 用于 tcp 通信 */ 25 /* if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) { */ // IPv4 26 if ((sockfd = socket(AF_INET6, SOCK_STREAM, 0)) < 0) { // IPv6 27 perror("Socket"); 28 exit(errno); 29 } 30 printf("socket created/n"); 31 32 /* 初始化服务器端（对方）的地址和端口信息 */ 33 bzero(&dest, sizeof(dest)); 34 /* dest.sin_family = AF_INET; */ // IPv4 35 dest.sin6_family = AF_INET6; // IPv6 36 /* dest.sin_port = htons(atoi(argv[2])); */ // IPv4 37 dest.sin6_port = htons(atoi(argv[2])); // IPv6 38 /* if (inet_aton(argv[1], (struct in_addr *) &dest.sin_addr.s_addr) == 0) { */ // IPv4 39 if ( inet_pton(AF_INET6, argv[1], &dest.sin6_addr) < 0 ) { // IPv6 40 perror(argv[1]); 41 exit(errno); 42 } 43 printf("address created/n"); 44 45 /* 连接服务器 */ 46 if (connect(sockfd, (struct sockaddr *) &dest, sizeof(dest)) != 0) { 47 perror("Connect "); 48 exit(errno); 49 } 50 printf("server connected/n"); 51 52 /* 接收对方发过来的消息，最多接收 MAXBUF 个字节 */ 53 bzero(buffer, MAXBUF + 1); 54 /* 接收服务器来的消息 */ 55 len = recv(sockfd, buffer, MAXBUF, 0); 56 if (len > 0) 57 printf("接收消息成功:'%s'，共%d个字节的数据/n", 58 buffer, len); 59 else 60 printf 61 ("消息接收失败！错误代码是%d，错误信息是'%s'/n", 62 errno, strerror(errno)); 63 64 bzero(buffer, MAXBUF + 1); 65 strcpy(buffer, "这是客户端发给服务器端的消息/n"); 66 /* 发消息给服务器 */ 67 len = send(sockfd, buffer, strlen(buffer), 0); 68 if (len < 0) 69 printf 70 ("消息'%s'发送失败！错误代码是%d，错误信息是'%s'/n", 71 buffer, errno, strerror(errno)); 72 else 73 printf("消息'%s'发送成功，共发送了%d个字节！/n", 74 buffer, len); 75 76 /* 关闭连接 */ 77 close(sockfd); 78 return 0; 79 }
编译程序用下列命令：
gcc -Wall ipv6-server.c -o ipv6server
gcc -Wall ipv6-client.c -o ipv6client
你自己的主机有IPv6地址吗？很多人会问，输入ifconfig命令看一下吧：
| eth0 链路封装:以太网 硬件地址 00:14:2A:6D:5B:A5 inet 地址:192.168.0.167 广播:192.168.0.255 掩码:255.255.255.0 inet6 地址: fe80::214:2aff:fe6d:5ba5/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 跃点数:1 接收数据包:30507 错误:0 丢弃:0 过载:0 帧数:0 发送数据包:26797 错误:0 丢弃:0 过载:0 载波:0 碰撞:0 发送队列长度:1000 接收字节:31461154 (30.0 MiB) 发送字节:4472810 (4.2 MiB) 中断:185 基本地址:0xe400 lo 链路封装:本地环回 inet 地址:127.0.0.1 掩码:255.0.0.0 inet6 地址: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 跃点数:1 接收数据包:13 错误:0 丢弃:0 过载:0 帧数:0 发送数据包:13 错误:0 丢弃:0 过载:0 载波:0 碰撞:0 发送队列长度:0 接收字节:1178 (1.1 KiB) 发送字节:1178 (1.1 KiB) |
看到“inet6 地址:”这两行了吗？后面就是你的IPv6地址
启动服务：
./ipv6server 7838 1
或者加上IP地址启动服务：
./ipv6server 7838 1 fe80::214:2aff:fe6d:5ba5
启动客户端测试一下：
./ipv6client ::1/128 7838
或
./ipv6client fe80::214:2aff:fe6d:5ba5 7838
二、UDP ipv6例子
UDP服务端：
1 #include <unistd.h> 2 #include <stdio.h> 3 #include <arpa/inet.h> 4 #include <sys/socket.h> 5 #include <string.h> 6 #define LOCALPORT 8888 7 int main(int argc,char *argv[]) 8 { 9 int mysocket,len; 10 int i=0; 11 struct sockaddr_in6 addr; 12 int addr_len; 13 char msg[200]; 14 char buf[300]; 15 16 if((mysocket=socket(AF_INET6,SOCK_DGRAM,0))<0) 17 { 18 perror("error:"); 19 return(1); 20 } 21 else 22 { 23 printf("socket created ...\n"); 24 printf("socket id :%d \n",mysocket); 25 } 26 27 addr_len=sizeof(struct sockaddr_in6); 28 bzero(&addr,sizeof(addr)); 29 addr.sin6_family=AF_INET6; 30 addr.sin6_port=htons(LOCALPORT); 31 addr.sin6_addr=in6addr_any; 32 33 if(bind(mysocket,(struct sockaddr *)&addr,sizeof(addr))<0) 34 { 35 perror("connect"); 36 return(1); 37 } 38 else 39 { 40 printf("bink ok .\n"); 41 printf("local port : %d\n",LOCALPORT); 42 } 43 while(1) 44 { 45 bzero(msg,sizeof(msg)); 46 len = recvfrom(mysocket,msg,sizeof(msg),0,(struct sockaddr *)&addr,(socklen_t*)&addr_len); 47 printf("%d:",i); 48 i++; 49 inet_ntop(AF_INET6,&addr.sin6_addr,buf,sizeof(buf)); 50 printf("message from ip %s",buf); 51 printf("Received message : %s\n",msg); 52 if(sendto(mysocket,msg,len,0,(struct sockaddr *)&addr,addr_len)<0) 53 { 54 printf("error"); 55 return(1); 56 } 57 } 58 }
UDP客户端代码：
1 #include <stdio.h> 2 #include <arpa/inet.h> 3 #include <unistd.h> 4 #include <sys/socket.h> 5 #include <string.h> 6 #define REMOTEPORT 8888 7 #define REMOTEIP "::1" 8 int main(int argc,char *argv[]) 9 { 10 int mysocket,len; 11 int i=0; 12 struct sockaddr_in6 addr; 13 int addr_len; 14 char msg[200]; 15 if((mysocket=socket(AF_INET6,SOCK_DGRAM,0))<0) 16 { 17 perror("error:"); 18 return(1); 19 } 20 else 21 { 22 printf("socket created ...\n"); 23 printf("socket id :%d \n",mysocket); 24 printf("rmote ip : %s\n",REMOTEIP); 25 printf("remote port :%d \n",REMOTEPORT); 26 } 27 28 addr_len=sizeof(struct sockaddr_in6); 29 bzero(&addr,sizeof(addr)); 30 addr.sin6_family=AF_INET6; 31 addr.sin6_port=htons(REMOTEPORT); 32 inet_pton(AF_INET6,REMOTEIP,&addr.sin6_addr); 33 34 while(1) 35 { 36 bzero(msg,sizeof(msg)); 37 len=read(STDIN_FILENO,msg,sizeof(msg)); 38 if(sendto(mysocket,msg,sizeof(msg),0,(struct sockaddr *)&addr,addr_len)<0) 39 { 40 printf("error"); 41 return(1); 42 } 43 len=recvfrom(mysocket,msg,sizeof(msg),0,(struct sockaddr *)&addr,(socklen_t*)&addr_len); 44 printf("%d:",i); 45 i++; 46 printf("Received message : %s\n",msg); 47 } 48 } 49
"::1"相当于ipv4下的lo，即127网段
三、ipv6环境下inet_pton和inet_ntop
附上一段ipv6环境下inet_pton和inet_ntop函数代码
1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <string.h> 4 #include <arpa/inet.h> 5 6 int main(int argc, char **argv) 7 { 8 unsigned char buf[sizeof(struct in6_addr)]; 9 int domain, s; 10 char str[INET6_ADDRSTRLEN]; 11 12 if(argc != 3){ 13 fprintf(stderr, "usage: %s {i4|i6|<num>} string\n", argv[0]); 14 exit(EXIT_FAILURE); 15 } 16 17 domain = (strcmp(argv[1], "i4") == 0) ? AF_INET:(strcmp(argv[1], "i6") == 0) ? AF_INET6 : atoi(argv[1]); 18 19 //IP字符串 ——》网络字节流 20 s = inet_pton(domain, argv[2], buf); 21 if(s<=0) 22 { 23 if(0 == s) 24 fprintf(stderr, "Not in presentation format\n"); 25 else 26 perror("inet_pton"); 27 exit(EXIT_FAILURE); 28 } 29 30 //网络字节流 ——》IP字符串 31 if(inet_ntop(domain, buf, str, INET6_ADDRSTRLEN) == NULL){ 32 perror("inet ntop\n"); 33 exit(EXIT_FAILURE); 34 } 35 printf("%s\n", str); 36 exit(EXIT_SUCCESS); 37 } 38
四、兼容IPV4和IPV6地址代码
为了能够兼容ipv4和ipv6，可以组织代码如下：
1 #define ADDRESS_BUFFER 50 2 3 typedef class address 4 { 5 private: 6 short int sin_family; //address family AF_INET or AF_INET6 7 union 8 { 9 char binary_addr4[IPV4_LEN]; 10 char binary_addr6[IPV6_LEN]; 11 }addr; 12 char readable_addr[ADDRESS_BUFFER]; 13 14 public: 15 address(); 16 bool operator == (const address &dst) const; 17 bool operator != (const address &dst) const { return (*this == dst? false : true );} 18 bool operator < (const address &dst) const; 19 const char* get_readable_address() const {return readable_addr;} 20 int get_family() const {return sin_family;} 21 bool is_ipv6() const {return sin_family == AF_INET6;} 22 void set_family(int af) {if(af != AF_INET && af != AF_INET6) return; sin_family = af;} 23 bool set_from_readable_address(const char* readable_address); 24 const char* get_binary_data() {return (char*)&addr;} 25 }address;
这里最重要的函数是set_from_readable_address函数，该函数是整个类的入口，执行该函数需要传入一个可读的IP地址，ipv4应该是"xxx.xxx.xxx.xxx"形式，ipv6应该是如：“ff01::1”或者"ffec:afaf::111"等可读的格式，返回false代表转换格式遇到错误，下面贴上该函数的实现代码，其它函数有兴趣的可以自己实现
1 bool address::set_from_readable_address(const char* readable_address) 2 { 3 if(readable_address == NULL) 4 return false; 5 memset(addr.binary_addr6, 0, sizeof(addr.binary_addr6)); 6 const char*p = readable_address; 7 int cnt = 0; 8 for(; *p != '\0';p++) 9 if(*p == ':') 10 cnt++; 11 if(cnt >= 2) 12 { 13 sin_family = AF_INET6; 14 if( inet_pton(PF_INET6,readable_address,addr.binary_addr6) <= 0) 15 return false; 16 strncpy(readable_addr, readable_address, ADDRESS_BUFFER); 17 }else 18 { 19 sin_family = AF_INET; 20 if( inet_pton(PF_INET,readable_address,addr.binary_addr4) <= 0) 21 return false; 22 strncpy(readable_addr, readable_address, ADDRESS_BUFFER); 23 } 24 return true; 25 }