我要追求平衡安逸的鄉間生活，卻又放不下城市中的燈紅酒綠，
我要尋找生命中的一片靜土，一直換居的生活，需要嘗試尋找與探險，
請給我一個居，讓我都市居蟹……尋找…歸宿……
Consider the following IPv4 code examples:
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdio.h>
#include <netdb.h>
...
main(argc, argv) /* client side */
int argc;
char *argv[];
{
struct sockaddr_in server;
struct servent *sp;
struct hostent *hp;
int s;
...
sp = getservbyname("login", "tcp");
if (sp == NULL) {
fprintf(stderr, "rlogin: tcp/login: unknown service\n");
exit(1);
}
hp = gethostbyname(argv[1]);
if (hp == NULL) {
fprintf(stderr, "rlogin: %s: unknown host\n", argv[1]);
exit(2);
}
memset((char *)&server, 0, sizeof(server));
memcpy((char *)&server.sin_addr, hp->h_addr, hp->h_length);
server.sin_len = sizeof(server);
server.sin_family = hp->h_addrtype;
server.sin_port = sp->s_port;
s = socket(AF_INET, SOCK_STREAM, 0);
if (s < 0) {
perror("rlogin: socket");
exit(3);
}
...
/* Connect does the bind for us */
if (connect(s, (struct sockaddr *)&server, sizeof(server)) < 0) {
perror("rlogin: connect");
exit(5);
}
...
exit(0);
}
#include <sys/types.h>This code can be ported to IPv6 with only a small number of changes.
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdio.h>
#include <netdb.h>
...
main(argc, argv) /* server side */
int argc;
char *argv[];
{
int f;
struct sockaddr_in from;
struct sockaddr_in sin;
struct servent *sp;
sp = getservbyname("login", "tcp");
if (sp == NULL) {
fprintf(stderr,
"rlogind: tcp/login: unknown service\n");
exit(1);
}
...
#ifndef DEBUG
/* Disassociate server from controlling terminal. */
...
#endif
memset((char *)&sin, 0, sizeof(sin));
sin.sin_len = sizeof(sockaddr_in);
sin.sin_port = sp->s_port; /* Restricted port */
sin.sin_addr.s_addr = INADDR_ANY;
...
f = socket(AF_INET, SOCK_STREAM, 0);
...
if (bind(f, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
...
}
...
listen(f, 5);
for (;;) {
int g, len = sizeof(from);
g = accept(f, (struct sockaddr *) &from, &len);
if (g < 0) {
if (errno != EINTR)
syslog(LOG_ERR, "rlogind: accept: %m");
continue;
}
if (fork() == 0) {
close(f);
doit(g, &from);
}
close(g);
}
exit(0);
}
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdio.h>
#include <netdb.h>
...
main(argc, argv) /* client side */
int argc;
char *argv[];
{
/* */
/* OLD code: struct sockaddr_in server; */
/* */
/* Change structure to sockaddr_in6 from sockaddr_in. */
/* */
struct sockaddr_in6 server;
struct servent *sp;
struct hostent *hp;
int s;
...
sp = getservbyname("login", "tcp");
if (sp == NULL) {
fprintf(stderr, "rlogin: tcp/login: unknown service\n");
exit(1);
}
/* */
/* OLD code: hp = gethostbyname(argv[1]); */
/* */
/* Use gethostbyname2 instead of gethostbyname. */
/* */
hp = gethostbyname2(argv[1], AF_INET6);
if (hp == NULL) {
fprintf(stderr, "rlogin: %s: unknown host\n", argv[1]);
exit(2);
}
memset((char *)&server, 0, sizeof(server));
/* */
/* OLD code: Not applicable. */
/* */
/* If the len member was not in the original IPv4 code*/
/* add it now and make sure it is sin6_len for IPv6. */
/* */
server.sin6_len = sizeof(server);
/* */
/* OLD code: memcpy((char *)&server.sin_addr, ... */
/* OLD code: server.sin_family = hp->h_addrtype; */
/* OLD code: server.sin_port = sp->s_port; */
/* */
/* Make sure you are using sockaddr_in6 members. */
/* */
memcpy((char *)&server.sin6_addr, hp->h_addr, hp->h_length);
server.sin6_family = hp->h_addrtype;
server.sin6_port = sp->s_port;
/* */
/* OLD code: s = socket(AF_INET, SOCK_STREAM, 0); */
/* */
/* Use the correct address family for IPv6. */
/* */
s = socket(AF_INET6, SOCK_STREAM, 0);
if (s < 0) {
perror("rlogin: socket");
exit(3);
}
...
/* Connect does the bind for us */
if (connect(s, (struct sockaddr *)&server, sizeof(server)) < 0) {
perror("rlogin: connect");
exit(5);
}
...
exit(0);
}
server.sin6_addr andserver.sin6_family hp->h_length will always behp->h_addrtype will#include <sys/types.h>As can be seen in the two IPv6 ported examples, there are only a few
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdio.h>
#include <netdb.h>
...
main(argc, argv) /* server side */
int argc;
char *argv[];
{
int f;
/* */
/* OLD code: struct sockaddr_in from; */
/* OLD code: struct sockaddr_in sin; */
/* */
/* Change structure to sockaddr_in6 from sockaddr_in. */
/* */
struct sockaddr_in6 from;
struct sockaddr_in6 sin;
struct servent *sp;
sp = getservbyname("login", "tcp");
if (sp == NULL) {
fprintf(stderr,
"rlogind: tcp/login: unknown service\n");
exit(1);
}
...
#ifndef DEBUG
/* Disassociate server from controlling terminal. */
...
#endif
memset((char *)&sin, 0, sizeof(sin));
/* */
/* OLD code: Not applicable. */
/* */
/* If the len member was not in the original IPv4 code*/
/* add it now and make sure it is sin6_len for IPv6. */
/* */
sin.sin6_len = sizeof(sin);
/* */
/* OLD code: sin.sin_port = sp->s_port; */
/* */
/* Make sure you are using sockaddr_in6 members. */
/* */
sin.sin6_port = sp->s_port; /* Restricted port */
/* */
/* OLD code: sin.sin_addr.s_addr = INADDR_ANY; */
/* */
/* Make the modifications for assigning in6addr_any to*/
/* sin6_addr. */
/* */
sin.sin6_addr = in6addr_any;
...
/* */
/* OLD code: f = socket(AF_INET, SOCK_STREAM, 0); */
/* */
/* Use the correct address family for IPv6. */
/* */
f = socket(AF_INET6, SOCK_STREAM, 0);
...
if (bind(f, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
...
}
...
listen(f, 5);
for (;;) {
int g, len = sizeof(from);
g = accept(f, (struct sockaddr *) &from, &len);
if (g < 0) {
if (errno != EINTR)
syslog(LOG_ERR, "rlogind: accept: %m");
continue;
}
if (fork() == 0) {
close(f);
doit(g, &from);
}
close(g);
}
exit(0);
}
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdio.h>
#include <netdb.h>
main(argc, argv) /* client side */
int argc;
char *argv[];
{
struct addrinfo req, *ans;
int code, s;
req.ai_flags = 0;
req.ai_family = PF_INET6; /* Same as AF_INET6. */
req.ai_socktype = SOCK_STREAM;
/* */
/* Use default protocol (in this case tcp) */
/* */
req.ai_protocol = 0;
if ((code = getaddrinfo(argv[1], "login", &req, &ans)) != 0) {
fprintf(stderr, "rlogin: getaddrinfo failed code %d\n",
code);
exit(1);
}
/* */
/* ans must contain at least one addrinfo, use */
/* the first. */
/* */
s = socket(ans->ai_family, ans->ai_socktype, ans->ai_protocol);
if (s < 0) {
perror("rlogin: socket");
exit(3);
}
...
/* Connect does the bind for us */
if (connect (s, ans->ai_addr, ans->ai_addrlen) < 0) {
perror("rlogin: connect");
exit(5);
}
...
/* */
/* Free answers after use */
/* */
freeaddrinfo(ans);
/* ... */
exit(0);
}
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdio.h>
#include <netdb.h>
main(argc, argv) /* server side */
int argc;
char *argv[];
{
struct sockaddr_in6 from;
struct addrinfo req, *ans;
int code, f, len;
/* */
/* Set ai_flags to AI_PASSIVE to indicate that return */
/* address is suitable for bind() */
/* */
req.ai_flags = AI_PASSIVE;
req.ai_family = PF_INET6; /* Same as AF_INET6. */
req.ai_socktype = SOCK_STREAM;
req.ai_protocol = 0;
if ((code = getaddrinfo(NULL, "login", &req, &ans)) != 0) {
fprintf(stderr, "rlogind: getaddrinfo failed code %d\n",
code);
exit(1);
}
...
#ifndef DEBUG
/* Disassociate server from controlling terminal. */
...
#endif
/* */
/* ans must contain at least one addrinfo, use */
/* the first. */
/* */
f = socket(ans->ai_family, ans->ai_socktype, ans->ai_protocol);
...
if (bind(f, ans->ai_addr, ans->ai_addrlen) < 0) {
...
}
listen(f, 5);
for (;;) {
int g, len = sizeof(from);
g = accept(f, (struct sockaddr *) &from, &len);
if (g < 0) {
if (errno != EINTR)
syslog(LOG_ERR, "rlogind: accept: %m");
continue;
}
if (fork() == 0) {
close(f);
doit(g, &from);
}
close(g);
}
/* */
/* Free answers after use */
/* */
freeaddrinfo(ans);
exit(0);
}