connect函数与karn算法

来源：互联网发布：店铺数据查看编辑：程序博客网时间：2024/05/21 09:11

先看connect函数：

#include <unistd.h>#include <sys/types.h>#include <sys/socket.h>#include <netdb.h>#include <stdio.h>#include <stdlib.h>#include <string.h>#include <ctype.h>#include <errno.h>#include <malloc.h>#include <netinet/in.h>#include <arpa/inet.h>#include <sys/ioctl.h>#include <stdarg.h>#include <fcntl.h>int main(){    int sockClient = socket(AF_INET, SOCK_STREAM, 0);    struct sockaddr_in addrSrv;    addrSrv.sin_addr.s_addr = inet_addr("1.2.3.4");    addrSrv.sin_family = AF_INET;    addrSrv.sin_port = htons(8765);    connect(sockClient, ( const struct sockaddr *)&addrSrv, sizeof(struct sockaddr_in));char szSendBuf[1024 * 64 * 10] = {0};int iRet = send(sockClient, szSendBuf, sizeof(szSendBuf) , 0); printf("send size is %d, iRet is %d\n", sizeof(szSendBuf), iRet);    getchar();    close(sockClient);    return 0;}

运行并抓包：

xxxxxx$ sudo tcpdump -iany port 8765 -nlps0tcpdump: verbose output suppressed, use -v or -vv for full protocol decodelistening on any, link-type LINUX_SLL (Linux cooked), capture size 65535 bytes23:58:48.918381 IP 10.100.70.139.48767 > 1.2.3.4.ultraseek-http: Flags [S], seq 1851659651, win 14280, options [mss 1428,sackOK,TS val 1238166474 ecr 0,nop,wscale 8], length 023:58:49.916564 IP 10.100.70.139.48767 > 1.2.3.4.ultraseek-http: Flags [S], seq 1851659651, win 14280, options [mss 1428,sackOK,TS val 1238166724 ecr 0,nop,wscale 8], length 023:58:51.920561 IP 10.100.70.139.48767 > 1.2.3.4.ultraseek-http: Flags [S], seq 1851659651, win 14280, options [mss 1428,sackOK,TS val 1238167225 ecr 0,nop,wscale 8], length 023:58:55.932564 IP 10.100.70.139.48767 > 1.2.3.4.ultraseek-http: Flags [S], seq 1851659651, win 14280, options [mss 1428,sackOK,TS val 1238168228 ecr 0,nop,wscale 8], length 0

过一会儿， connect函数超时，从抓包看，连接的时候，重传时间间隔分别为1， 2， 4秒，这就是之前介绍过的karn算法。

阅读全文

1 0