UNP函数笔记八: 名字与地址转换
来源：互联网 发布：企业网站怎样优化 编辑：程序博客网 时间：2024/04/27 06:07
第十一章 名字与地址转换:
#include <netdb.h>struct hostnet * gethostbyname(const char * hostname); error return NULL and set h_errno struct hostnet { char * h_name; /* official (canonical) name of host */ char ** h_aliases; /* alias name */ int h_addrtype; /* host addr type: AF_INET */ int h_length; /* length of address: 4 */ char ** h_addr_list; /* IPv4 addrs */ }; h_errno: HOST_NOT_FOUND, TRY_AGAIN, NO_RECOVERY, NO_DATA(NO_ADDRESS)#include <netdb.h>struct hostnet * gethostbyaddr(const char * addr, socklen_t len, int family); error return NULL and set h_errno addr: real type is struct in_addr family: AF_INET len: 4, sizeof(struct in_addr)#include <netdb.h>struct servent * getservbyname(const char * servname, const char * protoname); error return NULL struct servent { char * s_name; /* official service name */ char ** s_aliases; /* alias list */ int s_port; /* network byte order */ char * s_proto; /* protocol to use */ }; protoname: "tcp", "udp", NULL#include <netdb.h>struct servent * getservbyport(int port, const_char * protoname); error return NULL port: network byte order protoname: "tcp", "udp", NULL#include <netdb.h>int getaddrinfo(const char * hostname, const char * service, const struct addrinfo * hints, struct addrinfo ** result); success return 0, failed return error(EAI_xxx) error: EAI_AGAIN, EAI_BADFLAGS, EAI_FAIL, EAI_FAMILY, EAI_MEMORY, EAI_NONAME, EAI_OVERFLOW, EAI_SERVICE, EAI_SOCKTYPE, EAI_SYSTEM struct addrinfo { int ai_flags; int ai_family; int ai_socktype; int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */ socklen_t ai_addrlen; /* length of ai_addr */ char * ai_canonname; struct sockaddr * ai_addr; struct addrinfo * ai_next; }; hints only can set: ai_flags, ai_family, ai_socktype, ai_protocol ai_flags: AI_PASSIVE, AI_CANONNAME, AI_NUMERICHOST, AI_NUMERICSERV, AI_V4MAPPED, AI_ALL, AI_ADDRCONFIG#include <netdb.h>const char * gai_strerror(int error);#include <netdb.h>void freeaddrinfo(struct addrinfo * ai);some hostname: 0::0, 0.0.0.0; 0::1, 127.0.0.1#include <netdb.h>int getnameinfo(const struct sockaddr * sockaddr, socklen_t addrlen, char * host, socklen_t hostlen, char * serv, socklen_t servlen, int flags); success return 0, failed return error(EAI_xxx) flags: NI_DGRAM, NI_NAMEREQD, NI_NOFQDN, NI_NUMERICHOST, NI_NUMERICSCOPE, NI_NUMERICSERV#include <netdb.h>struct hostent * gethostbyname_r(const char * hostname, struct hostnet * result, char * buf, int buflen, int * h_errnop); error return NULL buflen should >= 8192struct hostent * gethostbyaddr_r(const char * addr, int len, int type, struct hostnet * result, char * buf, int buflen, int * h_errnop); error return NULL buflen should >= 8192other functions: getXXXent, setXXXent, endXXXent XXX:host, net, proto, serv getnetbyaddr, getnetbyname, getprotobyname, getprotobynumber示例:
#include <netdb.h>#include "err_exit.h"int main(int argc, char ** argv){ char * ptr; char ** pptr; char str[INET_ADDRSTRLEN]; struct hostent * hptr; while (--argc > 0) { ptr = *++argv; if ((hptr = gethostbyname(ptr)) == NULL) { printf("gethostbyname error for host: %s: %s\n", ptr, hstrerror(h_errno)); continue; } printf("official hostname: %s\n", hptr->h_name); for (pptr = hptr->h_aliases; *pptr != NULL; ++pptr) { printf("\talias: %s\n", *pptr); } switch (hptr->h_addrtype) { case AF_INET: { pptr = hptr->h_addr_list; for (; *pptr != NULL; ++pptr) { if (inet_ntop(hptr->h_addrtype, *pptr, str, sizeof(str)) == NULL) { err_exit("inet_ntop error"); } printf("\taddress: %s\n", str); } break; } default: { err_exit("unknown address type"); break; } } } exit(0);}#include <netdb.h>#include "err_exit.h"#include "sock_ntop.h"#define MAXLINE 4096int main(int argc, char ** argv){ int sockfd; int n; char * paddr; char recvline[MAXLINE + 1]; struct sockaddr_in servaddr; struct in_addr ** pptr; struct in_addr * inetaddrp[2]; struct in_addr inetaddr; struct hostent * hp; struct servent * sp; if (argc != 3) { printf("usage: daytimetcpcli1 <hostname> <service>\n"); exit(1); } if ((hp = gethostbyname(argv[1])) == NULL) { if (inet_aton(argv[1], &inetaddr) <= 0) { printf("hostname error for %s: %s\n", argv[1], hstrerror(h_errno)); exit(1); } else { inetaddrp[0] = &inetaddr; inetaddrp[1] = NULL; pptr = inetaddrp; } } else { pptr = (struct in_addr **)hp->h_addr_list; } if ((sp = getservbyname(argv[2], "tcp")) == NULL) { printf("gethostbyname error for host: %s: %s\n", argv[2], hstrerror(h_errno)); exit(1); } for (; *pptr != NULL; ++pptr) { if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) { err_exit("socket error"); } bzero(&servaddr, sizeof(servaddr)); servaddr.sin_family = AF_INET; servaddr.sin_port = sp->s_port; memcpy(&servaddr.sin_addr, *pptr, sizeof(struct in_addr)); if ((paddr = sock_ntop((struct sockaddr *)&servaddr, sizeof(servaddr))) == NULL) { err_exit("sock_ntop error"); } printf("trying %s\n", paddr); if (connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) == 0) { break; /* success */ } printf("connect error: %s\n", strerror(errno)); if (close(sockfd) == -1) { err_exit("close error"); } } if (*pptr == NULL) { printf("unable to connect"); exit(1); } while ((n = read(sockfd, recvline, MAXLINE)) > 0) { recvline[n] = '\0'; /* null terminate */ if (fputs(recvline, stdout) == EOF) { err_exit("fputs error"); } } if (n < 0) { err_exit("read error"); } exit(0);}#include <stdio.h>#include <netdb.h>#include <strings.h>struct addrinfo * host_serv(const char * host, const char * serv, int family, int socktype){ int n; struct addrinfo hints; struct addrinfo * res; bzero(&hints, sizeof(struct addrinfo)); hints.ai_flags = AI_CANONNAME; /* always return canonical name */ hints.ai_family = family; /* AF_UNSPEC, AF_INET, AF_INET6, etc. */ hints.ai_socktype = socktype; /* 0, SOCK_STREAM, SOCK_DGRAM, etc. */ if ((n = getaddrinfo(host, serv, &hints, &res)) != 0) { printf("host_serv error for %s, %s: %s\n", (host == NULL) ? "(no hostname)" : host, (serv == NULL) ? "(no servname)" : serv, gai_strerror(n)); exit(1); } return(res); /* return pointer to first on linked list */}#include <netdb.h>#include <strings.h>#include "err_exit.h"#define LISTENQ 1024int tcp_listen(const char * host, const char * serv, socklen_t * addrlenp){ int listenfd; int n; const int on = 1; struct addrinfo hints; struct addrinfo * res; struct addrinfo * ressave; bzero(&hints, sizeof(struct addrinfo)); hints.ai_flags = AI_PASSIVE; hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_STREAM; if ((n = getaddrinfo(host, serv, &hints, &res)) != 0) { printf("host_serv error for %s, %s: %s\n", (host == NULL) ? "(no hostname)" : host, (serv == NULL) ? "(no servname)" : serv, gai_strerror(n)); exit(1); } ressave = res; do { listenfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol); if (listenfd == -1) { continue; /* error, try next one */ } if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) { err_exit("setsockopt error"); } if (bind(listenfd, res->ai_addr, res->ai_addrlen) == 0) { break; /* success */ } /* bind error, close and try next one */ if (close(listenfd) == -1) { err_exit("close error"); } } while ((res = res->ai_next) != NULL); if (res == NULL) { /* errno from final socket() or bind() */ printf("tcp_listen error for %s, %s\n", host, serv); exit(1); } if (listen(listenfd, LISTENQ) == -1) { err_exit("listen error"); } if (addrlenp != NULL) { *addrlenp = res->ai_addrlen; /* return size of protocol address */ } freeaddrinfo(ressave); return(listenfd);}#include <netdb.h>#include <strings.h>#include "err_exit.h"int tcp_connect(const char * host, const char * serv){ int sockfd; int n; struct addrinfo hints; struct addrinfo * res; struct addrinfo * ressave; bzero(&hints, sizeof(struct addrinfo)); hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_STREAM; if ((n = getaddrinfo(host, serv, &hints, &res)) != 0) { printf("host_serv error for %s, %s: %s\n", (host == NULL) ? "(no hostname)" : host, (serv == NULL) ? "(no servname)" : serv, gai_strerror(n)); exit(1); } ressave = res; do { sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol); if (sockfd == -1) { continue; /* ignore this one */ } if (connect(sockfd, res->ai_addr, res->ai_addrlen) == 0) { break; /* success */ } if (close(sockfd) == -1) { err_exit("close error"); } } while ((res = res->ai_next) != NULL); freeaddrinfo(ressave); if (res == NULL) { /* errno set from final connect() */ printf("tcp_connect error for %s, %s\n", host, serv); exit(1); } return(sockfd);}#include <time.h>#include <netdb.h>#include "err_exit.h"#include "sock_ntop.h"#include "tcp_listen.h"#define MAXLINE 4096int main(int argc, char ** argv){ int n; int listenfd; int connfd; socklen_t len; socklen_t addrlen; char buff[MAXLINE]; time_t ticks; struct sockaddr_storage cliaddr; if (argc == 2) { listenfd = tcp_listen(NULL, argv[1], &addrlen); } else if (argc == 3) { listenfd = tcp_listen(argv[1], argv[2], &addrlen); } else { printf("usage: daytimetcpsrv2 [ <host> ] <service or port>\n"); exit(1); } for ( ; ; ) { len = sizeof(cliaddr); if ((connfd = accept(listenfd, (struct sockaddr *)&cliaddr, &len)) == -1) { err_exit("accept error"); } printf("connection from %s\n", sock_ntop((struct sockaddr *)&cliaddr, len)); ticks = time(NULL); snprintf(buff, sizeof(buff), "%.24s\r\n", ctime(&ticks)); n = strlen(buff); if (write(connfd, buff, n) != n) { err_exit("write error"); } if (close(connfd) == -1) { err_exit("close error"); } }}#include <netdb.h>#include "err_exit.h"#include "sock_ntop.h"#include "tcp_connect.h"#define MAXLINE 4096int main(int argc, char ** argv){ int sockfd; int n; char * paddr; char recvline[MAXLINE + 1]; socklen_t len; struct sockaddr_storage ss; if (argc != 3) { printf("usage: daytimetcpcli <hostname/IPaddress> <service/port#>\n"); exit(1); } sockfd = tcp_connect(argv[1], argv[2]); len = sizeof(ss); if (getpeername(sockfd, (struct sockaddr *)&ss, &len) == -1) { err_exit("getpeername error"); } if ((paddr = sock_ntop((struct sockaddr *)&ss, len)) == NULL) { err_exit("sock_ntop error"); } printf("connected to %s\n", paddr); while ((n = read(sockfd, recvline, MAXLINE)) > 0) { recvline[n] = '\0'; /* null terminate */ if (fputs(recvline, stdout) == EOF) { err_exit("fputs error"); } } if (n < 0) { err_exit("read error"); } exit(0);}#include <netdb.h>#include <strings.h>#include "err_exit.h"int udp_client(const char * host, const char * serv, struct sockaddr ** saptr, socklen_t * lenp){ int sockfd; int n; struct addrinfo hints; struct addrinfo * res; struct addrinfo * ressave; bzero(&hints, sizeof(struct addrinfo)); hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_DGRAM; if ((n = getaddrinfo(host, serv, &hints, &res)) != 0) { printf("host_serv error for %s, %s: %s\n", (host == NULL) ? "(no hostname)" : host, (serv == NULL) ? "(no servname)" : serv, gai_strerror(n)); exit(1); } ressave = res; do { sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol); if (sockfd != -1) { break; /* success */ } } while ((res = res->ai_next) != NULL); if (res == NULL) { /* errno set from final socket() */ printf("udp_client error for %s, %s\n", host, serv); } if ((*saptr = (struct sockaddr *)malloc(res->ai_addrlen)) == NULL) { err_exit("malloc error"); } memcpy(*saptr, res->ai_addr, res->ai_addrlen); if (lenp != NULL) { *lenp = res->ai_addrlen; } freeaddrinfo(ressave); return(sockfd);}#include <netdb.h>#include <strings.h>#include "err_exit.h"int udp_server(const char * host, const char * serv, socklen_t * addrlenp){ int sockfd; int n; struct addrinfo hints; struct addrinfo * res; struct addrinfo * ressave; bzero(&hints, sizeof(struct addrinfo)); hints.ai_flags = AI_PASSIVE; hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_DGRAM; if ((n = getaddrinfo(host, serv, &hints, &res)) != 0) { printf("host_serv error for %s, %s: %s\n", (host == NULL) ? "(no hostname)" : host, (serv == NULL) ? "(no servname)" : serv, gai_strerror(n)); exit(1); } ressave = res; do { sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol); if (sockfd == -1) { continue; /* error - try next one */ } if (bind(sockfd, res->ai_addr, res->ai_addrlen) == 0) { break; /* success */ } if (close(sockfd) == -1) { /* bind error - close and try next one */ err_exit("close error"); } } while ((res = res->ai_next) != NULL); if (res == NULL) { /* errno from final socket() or bind() */ printf("udp_server error for %s, %s\n", host, serv); exit(1); } if (addrlenp != NULL) { *addrlenp = res->ai_addrlen; /* return size of protocol address */ } freeaddrinfo(ressave); return(sockfd);}#include <netdb.h>#include <strings.h>#include "err_exit.h"int udp_connect(const char * host, const char * serv){ int sockfd; int n; struct addrinfo hints; struct addrinfo * res; struct addrinfo * ressave; bzero(&hints, sizeof(struct addrinfo)); hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_DGRAM; if ((n = getaddrinfo(host, serv, &hints, &res)) != 0) { printf("host_serv error for %s, %s: %s\n", (host == NULL) ? "(no hostname)" : host, (serv == NULL) ? "(no servname)" : serv, gai_strerror(n)); exit(1); } ressave = res; do { sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol); if (sockfd == -1) { continue; /* ignore this one */ } if (connect(sockfd, res->ai_addr, res->ai_addrlen) == 0) { break; /* success */ } if (close(sockfd) == -1) { err_exit("close error"); } } while ((res = res->ai_next) != NULL); if (res == NULL) { /* errno set from final connect() */ printf("udp_connect error for %s, %s\n", host, serv); } freeaddrinfo(ressave); return(sockfd);}#include <time.h>#include <netdb.h>#include "err_exit.h"#include "sock_ntop.h"#include "udp_server.h"#define MAXLINE 4096int main(int argc, char ** argv){ int sockfd; ssize_t n; char * paddr; char buff[MAXLINE]; time_t ticks; socklen_t len; struct sockaddr_storage cliaddr; if (argc == 2) { sockfd = udp_server(NULL, argv[1], NULL); } else if (argc == 3) { sockfd = udp_server(argv[1], argv[2], NULL); } else { printf("usage: daytimeudpsrv [ <host> ] <service or port>\n"); exit(1); } for ( ; ; ) { len = sizeof(cliaddr); n = recvfrom(sockfd, buff, MAXLINE, 0, (struct sockaddr *)&cliaddr, &len); if ((paddr = sock_ntop((struct sockaddr *)&cliaddr, len)) == NULL) { printf("sock_ntop error"); } printf("datagram from %s\n", paddr); ticks = time(NULL); snprintf(buff, sizeof(buff), "%.24s\r\n", ctime(&ticks)); n = strlen(buff); if (sendto(sockfd, buff, n, 0, (struct sockaddr *)&cliaddr, len) != n) { err_exit("sendto error"); } }}#include <netdb.h>#include "err_exit.h"#include "sock_ntop.h"#include "udp_client.h"#define MAXLINE 4096int main(int argc, char ** argv){ int sockfd; int n; char * paddr; char recvline[MAXLINE + 1]; socklen_t salen; struct sockaddr * sa; if (argc != 3) { printf("usage: daytimeudpcli1 <hostname/IPaddress> <service/port#>\n"); exit(1); } sockfd = udp_client(argv[1], argv[2], &sa, &salen); if ((paddr = sock_ntop(sa, salen)) == NULL) { err_exit("sock_ntop error"); } printf("sending to %s\n", paddr); if (sendto(sockfd, "", 1, 0, sa, salen) != 1) { /* send 1-byte datagram */ err_exit("sendto error"); } if (n = recvfrom(sockfd, recvline, MAXLINE, 0, NULL, NULL) < 0) { err_exit("recvfrom error"); } recvline[n] = '\0'; /* null terminate */ if (fputs(recvline, stdout) == EOF) { err_exit("fputs error"); } exit(0);}- UNP函数笔记八: 名字与地址转换
- UNP学习笔记（第十一章 名字与地址转换）
- 名字与地址转换函数笔记
- UNP总结 Chapter 11 名字与地址转换
- UNP卷1：第十一章（名字与地址转换）
- apue和unp的学习之旅11——名字与数值地址转换
- 名字与地址转换
- 《unix网络编程》（20）名字与地址转换函数
- UNIX网络编程笔记 第十一章 名字与地址转换
- 《UNIX网络编程 卷1》 笔记： 名字与地址转换
- 基本名字与地址转换
- 【UNP学习笔记】套接字地址相关函数
- 名字与IP地址转换编程
- 网络编程练习-名字与地址转换
- 第11章 名字与地址转换
- 名字与地址转换的函数，gethostbyname（）、gethostbyaddr（）函数
- Unix网络编程卷1第11章 名字与地址转换getservbyname 与 getservbyport函数
- 高级名字与地址转换————getaddrinfo()函数详解
- 在eclipse-php中添加svn插件
- UVa 409 - Excuses, Excuses!
- Android 相片管理专题之拍照功能
- How To Install Ubuntu 12.04 from USB Drive
- avl树
- UNP函数笔记八: 名字与地址转换
- C++:使用循环输出各种图形
- 快乐的程序员（一）
- Linux常用文件结构体
- 电路知识
- 编译期判断有向图中是否有环
- 阿拉伯数字转换成金额大写金额（包括小数）
- android 适配器Adpter的使用总结
- Objective-C中const常量是外连接的
