IPv6下网络编程socket， TCP和UDP例子，以及兼容IPV4和IPV6的类

一、TCP socket ipv6与ipv4的区别
服务器端源代码如下：

1 #include
2 #include
3 #include
4 #include
5 #include
6 #include
7 #include
8 #include
9 #include
10 #include
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
2 #include
3 #include
4 #include
5 #include
6 #include
7 #include
8 #include
9 #include
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：

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
2 #include
3 #include
4 #include
5 #include
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
2 #include
3 #include
4 #include
5 #include
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
2 #include
3 #include
4 #include
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|} 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 charp = 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 }