第六天：网络处理（anet部分）-- redis源码慢慢学，慢慢看【redis6.0.6】
【摘要】
文章目录
前奏初潮高潮迭起工具包anet.canetTcpConnect 潮落anetUnixConnectRead、Write时间、心跳，相关 高潮再起anetResolve字节序转换
前奏
今天，我找回了阔别已久的迷路的感觉，我觉得，顺序什么的，算了算了，还是按照我的喜好来。 所以，这两天我决定学习网络模块。
网络模块的文件：
依...
前奏
今天，我找回了阔别已久的迷路的感觉，我觉得，顺序什么的，算了算了，还是按照我的喜好来。
所以，这两天我决定学习网络模块。
网络模块的文件：
依旧要房山管理放上人家的版权：
- Copyright © 2006-2012, Salvatore Sanfilippo
- All rights reserved.
初潮
ane.c和anet.h中的内容主要用于简单的TCP Socket连接。
先来看一下头文件，一半是熟悉的面孔，一半听我说完也是熟悉的面孔了嘿嘿
#ifndef ANET_H
#define ANET_H
#include <sys/types.h>
#define ANET_OK 0
#define ANET_ERR -1
#define ANET_ERR_LEN 256
/* Flags used with certain functions. */
#define ANET_NONE 0
#define ANET_IP_ONLY (1<<0)
#if defined(__sun) || defined(_AIX)
#define AF_LOCAL AF_UNIX
#endif
#ifdef _AIX
#undef ip_len
#endif
int anetTcpConnect(char *err, const char *addr, int port); //TCP的默认连接
int anetTcpNonBlockConnect(char *err, const char *addr, int port); //TCP的非阻塞连接
int anetTcpNonBlockBindConnect(char *err, const char *addr, int port, const char *source_addr); //TCP的非阻塞绑定
int anetTcpNonBlockBestEffortBindConnect(char *err, const char *addr, int port, const char *source_addr);
//字面意思啊：TCP的最高效非阻塞绑定，等下我倒要看看到底是何方神圣，虽然我心里有个答案了
//下面俩是unix的
int anetUnixConnect(char *err, const char *path);
int anetUnixNonBlockConnect(char *err, const char *path);
int anetRead(int fd, char *buf, int count);
int anetResolve(char *err, char *host, char *ipbuf, size_t ipbuf_len); //解析所有东西
int anetResolveIP(char *err, char *host, char *ipbuf, size_t ipbuf_len);//单单解析IP
int anetTcpServer(char *err, int port, char *bindaddr, int backlog);
int anetTcp6Server(char *err, int port, char *bindaddr, int backlog);
int anetUnixServer(char *err, char *path, mode_t perm, int backlog);
int anetTcpAccept(char *err, int serversock, char *ip, size_t ip_len, int *port);
int anetUnixAccept(char *err, int serversock);
int anetWrite(int fd, char *buf, int count);
int anetNonBlock(char *err, int fd); //anet设置非阻塞的方法
int anetBlock(char *err, int fd);
int anetEnableTcpNoDelay(char *err, int fd); //启用非延迟
int anetDisableTcpNoDelay(char *err, int fd);
int anetTcpKeepAlive(char *err, int fd); //心跳保活机制
int anetSendTimeout(char *err, int fd, long long ms);
int anetRecvTimeout(char *err, int fd, long long ms);
int anetPeerToString(int fd, char *ip, size_t ip_len, int *port); //转换网络字节序
int anetKeepAlive(char *err, int fd, int interval);
int anetSockName(int fd, char *ip, size_t ip_len, int *port);
//格式化，等下看看是何方神圣
int anetFormatAddr(char *fmt, size_t fmt_len, char *ip, int port);
int anetFormatPeer(int fd, char *fmt, size_t fmt_len);
int anetFormatSock(int fd, char *fmt, size_t fmt_len);
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高潮迭起
工具包
通过域名获取主机IP - struct addrinfo
SOCKET网络编程 - 通俗易懂入门篇
setsockopt与getsockopt
anet.c
anetTcpConnect
int anetTcpConnect(char *err, const char *addr, int port)
{ return anetTcpGenericConnect(err,addr,port,NULL,ANET_CONNECT_NONE);
}
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/*
参数释义：
addr：传入服务器地址信息，其中内容将用于创建监听套接字
source_addr：相当于客户端地址信息
flags：这我还真没看明白。。。再最后一块儿，注释给出了，如果没猜错，应该是和仅打开监听套接字有关的
*/
static int anetTcpGenericConnect(char *err, const char *addr, int port,const char *source_addr, int flags)
{ int s = ANET_ERR, rv; char portstr[6]; /* strlen("65535") + 1; */ struct addrinfo hints, *servinfo, *bservinfo, *p, *b; snprintf(portstr,sizeof(portstr),"%d",port); memset(&hints,0,sizeof(hints)); hints.ai_family = AF_UNSPEC; //未指定 hints.ai_socktype = SOCK_STREAM;//有序、可靠、面向连接的双向字节流 if ((rv = getaddrinfo(addr,portstr,&hints,&servinfo)) != 0) { //解析addr信息，存入 servinfo //不懂一定要看上面的工具包，写了一晚上呢 anetSetError(err, "%s", gai_strerror(rv)); //这个不管它，报错函数而已 return ANET_ERR; } for (p = servinfo; p != NULL; p = p->ai_next) { //工具包里有说，给你一个addrinfo，它可能是一串 /* Try to create the socket and to connect it. * If we fail in the socket() call, or on connect(), we retry with * the next entry in servinfo. */ if ((s = socket(p->ai_family,p->ai_socktype,p->ai_protocol)) == -1) //这里s成为了监听套接字 continue; //如果没打开，那就继续循环，无碍 if (anetSetReuseAddr(err,s) == ANET_ERR) goto error; //设置地址重用 if (flags & ANET_CONNECT_NONBLOCK && anetNonBlock(err,s) != ANET_OK) //设置非阻塞 goto error; if (source_addr) { //source_addr：传入参数 int bound = 0; /* Using getaddrinfo saves us from self-determining IPv4 vs IPv6 */ if ((rv = getaddrinfo(source_addr, NULL, &hints, &bservinfo)) != 0) //内啥，不多说了啊 { anetSetError(err, "%s", gai_strerror(rv)); goto error; } for (b = bservinfo; b != NULL; b = b->ai_next) { if (bind(s,b->ai_addr,b->ai_addrlen) != -1) { bound = 1; break; } } freeaddrinfo(bservinfo); if (!bound) { anetSetError(err, "bind: %s", strerror(errno)); goto error; } } //for循环到这里结束 if (connect(s,p->ai_addr,p->ai_addrlen) == -1) { /* If the socket is non-blocking, it is ok for connect() to * return an EINPROGRESS error here. */ if (errno == EINPROGRESS && flags & ANET_CONNECT_NONBLOCK) goto end; close(s); s = ANET_ERR; continue; } /* If we ended an iteration of the for loop without errors, we * have a connected socket. Let's return to the caller. */ goto end; } if (p == NULL) anetSetError(err, "creating socket: %s", strerror(errno));
error: if (s != ANET_ERR) { close(s); s = ANET_ERR; }
end: freeaddrinfo(servinfo); /* Handle best effort binding: if a binding address was used, but it is * not possible to create a socket, try again without a binding address. */ if (s == ANET_ERR && source_addr && (flags & ANET_CONNECT_BE_BINDING)) { //#define ANET_CONNECT_BE_BINDING 2 /* Best effort binding. */ return anetTcpGenericConnect(err,addr,port,NULL,flags); } else { return s; }
}
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int anetTcpNonBlockBindConnect(char *err, const char *addr, int port,const char *source_addr)
{ return anetTcpGenericConnect(err,addr,port,source_addr,ANET_CONNECT_NONBLOCK);
}
int anetTcpNonBlockBestEffortBindConnect(char *err, const char *addr, int port,const char *source_addr)
{ return anetTcpGenericConnect(err,addr,port,source_addr,ANET_CONNECT_NONBLOCK|ANET_CONNECT_BE_BINDING);
}
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潮落
anetUnixConnect
int anetUnixConnect(char *err, const char *path)
{ return anetUnixGenericConnect(err,path,ANET_CONNECT_NONE);
}
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int anetUnixGenericConnect(char *err, const char *path, int flags)
{ int s; struct sockaddr_un sa; if ((s = anetCreateSocket(err,AF_LOCAL)) == ANET_ERR) //在下边，简单调用而已，本地连接 return ANET_ERR; sa.sun_family = AF_LOCAL; //既然是本地连接，那就不多说了 strncpy(sa.sun_path,path,sizeof(sa.sun_path)-1); if (flags & ANET_CONNECT_NONBLOCK) { if (anetNonBlock(err,s) != ANET_OK) { close(s); return ANET_ERR; } } if (connect(s,(struct sockaddr*)&sa,sizeof(sa)) == -1) { if (errno == EINPROGRESS && flags & ANET_CONNECT_NONBLOCK) return s; anetSetError(err, "connect: %s", strerror(errno)); close(s); return ANET_ERR; } return s;
}
static int anetCreateSocket(char *err, int domain) { int s; if ((s = socket(domain, SOCK_STREAM, 0)) == -1) { anetSetError(err, "creating socket: %s", strerror(errno)); return ANET_ERR; } /* Make sure connection-intensive things like the redis benchmark * will be able to close/open sockets a zillion of times */ if (anetSetReuseAddr(err,s) == ANET_ERR) { close(s); return ANET_ERR; } return s;
}
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int anetUnixNonBlockConnect(char *err, const char *path)
{ return anetUnixGenericConnect(err,path,ANET_CONNECT_NONBLOCK);
}
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Read、Write
int anetRead(int fd, char *buf, int count)
{ ssize_t nread, totlen = 0; while(totlen != count) { nread = read(fd,buf,count-totlen); if (nread == 0) return totlen; if (nread == -1) return -1; totlen += nread; buf += nread; } return totlen;
}
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int anetWrite(int fd, char *buf, int count)
{ ssize_t nwritten, totlen = 0; while(totlen != count) { nwritten = write(fd,buf,count-totlen); if (nwritten == 0) return totlen; if (nwritten == -1) return -1; totlen += nwritten; buf += nwritten; } return totlen;
}
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这俩已经太熟了，也不知道要说啥
时间、心跳，相关
/* Set the socket send timeout (SO_SNDTIMEO socket option) to the specified
* number of milliseconds, or disable it if the 'ms' argument is zero. */
int anetSendTimeout(char *err, int fd, long long ms) { struct timeval tv; tv.tv_sec = ms/1000; tv.tv_usec = (ms%1000)*1000; if (setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv)) == -1) { anetSetError(err, "setsockopt SO_SNDTIMEO: %s", strerror(errno)); return ANET_ERR; } return ANET_OK;
}
/* Set the socket receive timeout (SO_RCVTIMEO socket option) to the specified
* number of milliseconds, or disable it if the 'ms' argument is zero. */
int anetRecvTimeout(char *err, int fd, long long ms) { struct timeval tv; tv.tv_sec = ms/1000; tv.tv_usec = (ms%1000)*1000; if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) == -1) { anetSetError(err, "setsockopt SO_RCVTIMEO: %s", strerror(errno)); return ANET_ERR; } return ANET_OK;
}
//如果对setsockopt不了解，没事儿，我在上边补了个工具包。
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int anetTcpKeepAlive(char *err, int fd)
{ int yes = 1; if (setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &yes, sizeof(yes)) == -1) { anetSetError(err, "setsockopt SO_KEEPALIVE: %s", strerror(errno)); return ANET_ERR; } return ANET_OK;
}
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高潮再起
anetResolve
int anetResolve(char *err, char *host, char *ipbuf, size_t ipbuf_len) { return anetGenericResolve(err,host,ipbuf,ipbuf_len,ANET_NONE);
}
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int anetGenericResolve(char *err, char *host, char *ipbuf, size_t ipbuf_len,int flags)
{ struct addrinfo hints, *info; int rv; memset(&hints,0,sizeof(hints)); if (flags & ANET_IP_ONLY) hints.ai_flags = AI_NUMERICHOST; hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_STREAM; /* specify socktype to avoid dups */ if ((rv = getaddrinfo(host, NULL, &hints, &info)) != 0) { anetSetError(err, "%s", gai_strerror(rv)); return ANET_ERR; } if (info->ai_family == AF_INET) { struct sockaddr_in *sa = (struct sockaddr_in *)info->ai_addr; inet_ntop(AF_INET, &(sa->sin_addr), ipbuf, ipbuf_len); } else { struct sockaddr_in6 *sa = (struct sockaddr_in6 *)info->ai_addr; inet_ntop(AF_INET6, &(sa->sin6_addr), ipbuf, ipbuf_len); } freeaddrinfo(info); return ANET_OK;
}
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好滴吧，没有前面那个那么猛烈
int anetResolveIP(char *err, char *host, char *ipbuf, size_t ipbuf_len) { return anetGenericResolve(err,host,ipbuf,ipbuf_len,ANET_IP_ONLY);
}
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字节序转换
int anetPeerToString(int fd, char *ip, size_t ip_len, int *port) { struct sockaddr_storage sa; socklen_t salen = sizeof(sa); if (getpeername(fd,(struct sockaddr*)&sa,&salen) == -1) goto error; if (ip_len == 0) goto error; if (sa.ss_family == AF_INET) { struct sockaddr_in *s = (struct sockaddr_in *)&sa; if (ip) inet_ntop(AF_INET,(void*)&(s->sin_addr),ip,ip_len); if (port) *port = ntohs(s->sin_port); } else if (sa.ss_family == AF_INET6) { struct sockaddr_in6 *s = (struct sockaddr_in6 *)&sa; if (ip) inet_ntop(AF_INET6,(void*)&(s->sin6_addr),ip,ip_len); if (port) *port = ntohs(s->sin6_port); } else if (sa.ss_family == AF_UNIX) { if (ip) strncpy(ip,"/unixsocket",ip_len); if (port) *port = 0; } else { goto error; } return 0;
error: if (ip) { if (ip_len >= 2) { ip[0] = '?'; ip[1] = '\0'; } else if (ip_len == 1) { ip[0] = '\0'; } } if (port) *port = 0; return -1;
}
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好累啊，那要不就到这儿吧，其他的基本是调用调用再调用，工具包里有。
建议收藏，不然刷着刷着就可能找不到了
建议关注，博主写的还行吧
文章来源: lion-wu.blog.csdn.net，作者：看，未来，版权归原作者所有，如需转载，请联系作者。
原文链接：lion-wu.blog.csdn.net/article/details/108513647
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