以此纪念刚开始在linux上学习网络编程的失败-_-!

以此纪念刚开始在linux上学习网络编程的失败-_-!

write by
九天雁翎(JTianLing) -- blog.csdn.net/vagrxie

讨论新闻组及文件


从一开始的学习到现在，我的Ubuntu 8.04服务器版本就从来没有正常的跑过一个服务器程序，亏它还是服务器版本的，郁闷的我要死。目前为止的正常的服务器端网络程序都是在Windows下运行成功的，比如第一次那个daytime服务器，都是靠着移植到windows下才能成功，不过不停的调试啊，调试啊，gdb倒是熟悉了不少，还顺面熟悉了一堆的网络调试工具，linux下的netstat,tcpdump，windows下的Wireshark（linux因为没有X
window，所以用不了）倒是真熟悉了很多，我都真不知道这样的死Ubuntu对于学习是好是坏了，假如没有碰到这么多问题的话，我不会调试一个那样简单的程序那么多次，不会这样的进一步熟悉那些特别简单的套接口API,真是，郁闷了。
中间发帖求救，有人说是防火墙，我配置了半天也没有反应，直接将ufw,iptables什么的都卸载了，结果还是不行！
最新的调试结果就是netstat显示的确服务器端listen成功了，
tcpdump可以看到客户端的发送的SYN包，但是就是服务器不回ACK包，郁闷的客户端所以总是不停的发送几次SYN包，然后connect
failed了，奇怪的家伙，我今晚准备下个ubuntu的普通版本试一下，服务器版本可能为了安全做了太多的手脚，我配置linux的能力又那么弱-_-!光学些bash,makefile什么的，对于配置文件的修改实在是不行，不然我也不会为了samba的配置郁闷到死，然后干脆传输文件都直接改用WinSCP，通过SSH传输，而不是通过共享了。唉。。。。。还是公司好，有管理员。
ubuntu普通版本还不行，我就只好换回FC了。。。。刚才看了一下已经到10了-_-!我上一次用的时候还是FC6呢，那时候4，5张盘，现在FC10只有1CD了，最近的操作系统瘦身工程进行的还挺彻底。要知道，连最最老的经典的RH9那时候都是4张盘。
呵呵，其实想起来，看的其实是UNIX的书，弄个真正的UNIX，比如FreeBSD什么的应该也挺不错的，可惜最近工作那个忙的啊。。。。都快吐血了，游戏快要上大规模的内测了，老总，总监催进度催的我一天头是大的，刚开始弄游戏的主逻辑服务器，第二天就要我设计并添加模块-_-!实在是@#%#$^@#$^$%@&$%基本上就那句话，不能上硬着头皮眯着眼睛也要上！唉。。。。所以嘛，还是暂时收收心吧。。。好好把网络编程学好都不错了，连Linux都没有弄转，呵呵，还是老实点好。

以下是我痛苦的调试经历：-_-!
@ubuntu:~$ netstat -a
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address
Foreign Address State
tcp
0 0 *:13000
*:* LISTEN


@ubuntu:~$ netstat -a
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address
Foreign Address State
tcp
0 0 *:daytime *:*
LISTEN

@ubuntu:~$ netstat -a
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address
Foreign Address State
tcp
0 0 *:9877
*:* LISTEN

三个不同的程序，都是卡在listen上。。。。
@ubuntu:~/test/testclient$ ./test 127.0.0.1
connet failed.
@ubuntu:~/test/testclient$ ./test 127.0.0.1
connet failed.

可怜的客户端啊。。。一次一次的connet failed
其实它实在不停的尝试的。。。。
一次：
@ubuntu:~$ sudo tcpdump port 9877
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
22:04:03.173472 IP 192.168.0.158.46269 > localhost.9877: S 1088742785:1088742785(0) win 5840 <mss 1460,sackOK,timestamp
95154 0,nop,wscale 4>
22:04:06.171580 IP 192.168.0.158.46269 > localhost.9877: S 1088742785:1088742785(0) win 5840 <mss 1460,sackOK,timestamp
95904 0,nop,wscale 4>

两次：
@ubuntu:~$ sudo tcpdump port 9877 -vv
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
22:05:09.022315 IP (tos 0x0, ttl 64, id 16507, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.46270 >
localhost.9877: S, cksum 0xef4b (correct), 2110715003:2110715003(0) win 5840 <mss 1460,sackOK,timestamp 111616 0,nop,wscale 4>
22:05:12.019572 IP (tos 0x0, ttl 64, id 16508, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.46270 >
localhost.9877: S, cksum 0xec5d (correct), 2110715003:2110715003(0) win 5840 <mss 1460,sackOK,timestamp 112366 0,nop,wscale 4>
22:05:18.019572 IP (tos 0x0, ttl 64, id 16509, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.46270 >
localhost.9877: S, cksum 0xe681 (correct), 2110715003:2110715003(0) win 5840 <mss 1460,sackOK,timestamp 113866 0,nop,wscale 4>
22:05:30.019593 IP (tos 0x0, ttl 64, id 16510, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.46270 >
localhost.9877: S, cksum 0xdac9 (correct), 2110715003:2110715003(0) win 5840 <mss 1460,sackOK,timestamp 116866 0,nop,wscale 4>
22:05:54.019575 IP (tos 0x0, ttl 64, id 16511, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.46270 >
localhost.9877: S, cksum 0xc359 (correct), 2110715003:2110715003(0) win 5840 <mss 1460,sackOK,timestamp 122866 0,nop,wscale 4>
22:06:42.019581 IP (tos 0x0, ttl 64, id 16512, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.46270 >
localhost.9877: S, cksum 0x9479 (correct), 2110715003:2110715003(0) win 5840 <mss 1460,sackOK,timestamp 134866 0,nop,wscale 4>

6 packets captured
6 packets received by filter
0 packets dropped by kernel

三次：
@ubuntu:~$ sudo tcpdump port 13000 -vv
[sudo] password for xqh:
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
22:44:49.480945 IP (tos 0x0, ttl 64, id 10118, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.60205 >
localhost.13000: S, cksum 0xebc4 (correct), 793636653:793636653(0) win 5840 <mss 1460,sackOK,timestamp 706731 0,nop,wscale 4>
22:44:52.479579 IP (tos 0x0, ttl 64, id 10119, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.60205 >
localhost.13000: S, cksum 0xe8d6 (correct), 793636653:793636653(0) win 5840 <mss 1460,sackOK,timestamp 707481 0,nop,wscale 4>
22:44:58.479574 IP (tos 0x0, ttl 64, id 10120, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.60205 >
localhost.13000: S, cksum 0xe2fa (correct), 793636653:793636653(0) win 5840 <mss 1460,sackOK,timestamp 708981 0,nop,wscale 4>
22:45:10.479576 IP (tos 0x0, ttl 64, id 10121, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.60205 >
localhost.13000: S, cksum 0xd742 (correct), 793636653:793636653(0) win 5840 <mss 1460,sackOK,timestamp 711981 0,nop,wscale 4>
22:45:34.479596 IP (tos 0x0, ttl 64, id 10122, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.60205 >
localhost.13000: S, cksum 0xbfd2 (correct), 793636653:793636653(0) win 5840 <mss 1460,sackOK,timestamp 717981 0,nop,wscale 4>
22:46:22.479584 IP (tos 0x0, ttl 64, id 10123, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.60205 >
localhost.13000: S, cksum 0x90f2 (correct), 793636653:793636653(0) win 5840 <mss 1460,sackOK,timestamp 729981 0,nop,wscale 4>
22:49:22.209124 IP (tos 0x0, ttl 64, id 2573, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.49879 > localhost.13000:
S, cksum 0x20c8 (correct), 778754316:778754316(0) win 5840 <mss 1460,sackOK,timestamp 774913 0,nop,wscale 4>
22:49:25.207577 IP (tos 0x0, ttl 64, id 2574, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.49879 > localhost.13000:
S, cksum 0x1dda (correct), 778754316:778754316(0) win 5840 <mss 1460,sackOK,timestamp 775663 0,nop,wscale 4>
22:49:31.207570 IP (tos 0x0, ttl 64, id 2575, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.49879 > localhost.13000:
S, cksum 0x17fe (correct), 778754316:778754316(0) win 5840 <mss 1460,sackOK,timestamp 777163 0,nop,wscale 4>
22:49:43.207579 IP (tos 0x0, ttl 64, id 2576, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.49879 > localhost.13000:
S, cksum 0x0c46 (correct), 778754316:778754316(0) win 5840 <mss 1460,sackOK,timestamp 780163 0,nop,wscale 4>
22:50:07.207588 IP (tos 0x0, ttl 64, id 2577, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.49879 > localhost.13000:
S, cksum 0xf4d5 (correct), 778754316:778754316(0) win 5840 <mss 1460,sackOK,timestamp 786163 0,nop,wscale 4>
22:50:55.207580 IP (tos 0x0, ttl 64, id 2578, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.158.49879 > localhost.13000:
S, cksum 0xc5f5 (correct), 778754316:778754316(0) win 5840 <mss 1460,sackOK,timestamp 798163 0,nop,wscale 4>

记住，就算我不改一个字，原《UNIX Network Programming》第一卷第三版一书的源程序（我试过4，5个前面几章的例子了），都是可以编译，可以运行，但是状况都是同样的。。。那就是connect不会成功。-_-!
处于对于原程序的一丝不信任，我自己重写了一些程序，但是几乎同样的程序，在Windows下相当的正常，但是在Ubuntu
8.04服务器版本上，还是同样的状况！！有没有人可以给我个解释啊。。。。。朝闻道夕死可矣。。。。。

举个例子，比如，linux下的两个程序：
服务器端：
1
#include
<stdio.h>

2 #include
<stdlib.h>

3 #include
<sys/socket.h>

4 #include
<sys/time.h>

5 #include
<time.h>

6 #include
<netinet/in.h>

7 #include
<errno.h>

8 #include
<string.h>

9 #include
<unistd.h>

10

11

12 #define MAXLINE
1000

13 int main(int argc,
char* argv[])

14 {

15 int listenfd, connfd;

16 struct sockaddr_in servaddr;

17 //char buff[MAXLINE] = {0};

18 //time_t ticks;

19

20 listenfd = socket(AF_INET, SOCK_STREAM,
0);

21 if(0 == listenfd)

22 {

23 printf("socket Error./n");

24 return -1;

25 }

26

27 memset(&servaddr,
0, sizeof(servaddr));

28 servaddr.sin_family = AF_INET;

29 servaddr.sin_addr.s_addr = htonl(INADDR_ANY);

30 servaddr.sin_port = htons(13000);
/* daytime server */

31

32 if(
0 != bind(listenfd, (struct sockaddr*)&servaddr,
sizeof(servaddr)))

33 {

34 printf("bind error./n");

35 close(listenfd);

36 return -1;

37 }

38

39 if(
0 != listen(listenfd,
10))

40 {

41 printf("listen error./n");

42 close(listenfd);

43 return -1;

44 }

45

46 printf("listen right./n");

47

48 char buffRecv[MAXLINE] = {0};

49 connfd = accept(listenfd, (struct sockaddr*)NULL,
NULL);

50

51 printf("have accept./n");

52

53 while(true)

54 {

55 int n =
0;

56 if(
0 == (n = read(connfd, buffRecv, MAXLINE)) )

57 {

58 printf("recv failed/n");

59 break;

60 }

61 buffRecv
=
0;

62 if(
0 == (n = write(connfd, buffRecv, strlen(buffRecv))) )

63 {

64 printf("send failed./n");

65 break;

66 }

67 fputs(buffRecv,
stdout);

68 }

69 close(connfd);

70 exit(0);

71 }

72

客户端：
1
#include
<stdio.h>

2 #include
<stdlib.h>

3 #include
<sys/socket.h>

4 #include
<sys/time.h>

5 #include
<time.h>

6 #include
<netinet/in.h>

7 #include
<errno.h>

8 #include
<string.h>

9 #include
<unistd.h>

10 #include
<arpa/inet.h>

11

12 #define MAXLINE
1000

13

14 void str_cli(FILE *fp,
int sockfd)

15 {

16 char sendline[MAXLINE] = {0};

17 char recvline[MAXLINE] = {0};

18 while ( (fgets(sendline, MAXLINE, fp)) !=
NULL)

19 {

20

21 if(0 == send(sockfd, sendline, strlen(sendline),
0))

22 {

23 printf("send failed./n");

24 break ;

25 }

26 }

27 close(sockfd);

28 }

29

30 int main(int argc,
char* argv[])

31 {

32 if (argc !=
2)

33 {

34 printf("usage: tcpcli <IPaddress>");

35 exit(1);

36 }

37

38 int sockfd =
0;

39 sockfd = socket(AF_INET, SOCK_STREAM,
0);

40

41 struct sockaddr_in servaddr;

42 memset(&servaddr,
0, sizeof(servaddr));

43 servaddr.sin_family = AF_INET;

44 servaddr.sin_addr.s_addr = inet_addr(argv[1]);

45 servaddr.sin_port = htons(13000);
/* daytime server */

46

47 if(
0 != connect(sockfd, (struct sockaddr *)&servaddr,
sizeof(servaddr)))

48 {

49 printf("connet failed./n");

50 close(sockfd);

51 return -1;

52 }

53

54 str_cli(stdin, sockfd); /* do it all */

55 exit(0);

56 }

57


就这么简单的程序，硬是成功不了，何解？
几乎同样的程序，比如：
服务器端：
#include
"Winsock2.h"
//#include "python.h"

//void CallPython(const char* apszPy)
//{
//
Py_Initialize();
//
//
PyRun_SimpleString(apszPy);
//
//
Py_Finalize();
//}
#define
MAXLINE 1000
int
main(int
argc, char **argv)
{

WORD wVersionRequested;

WSADATA wsaData;

int err;


wVersionRequested =
MAKEWORD( 2, 2 );


// windows下此初始化为必须

err = WSAStartup(
wVersionRequested, &wsaData );

if ( err != 0 ) {

return -1;

}


SOCKET listenfd,
connfd;

struct sockaddr_in
servaddr;

char buff[MAXLINE];

time_t ticks;


listenfd =
socket(AF_INET,
SOCK_STREAM, 0);

if(INVALID_SOCKET ==
listenfd)

{

printf("socket Error: %d",WSAGetLastError());

return -1;

}


ZeroMemory(&servaddr,
sizeof(servaddr));

servaddr.sin_family
= AF_INET;

servaddr.sin_addr.s_addr =
htonl(INADDR_ANY);

servaddr.sin_port
= htons(13); /* daytime server */


bind(listenfd, (struct
sockaddr*)&servaddr,
sizeof(servaddr));


listen(listenfd,
SOMAXCONN);


char buffRecv[MAXLINE] = {0};



connfd = accept(listenfd, (struct
sockaddr*)NULL,
NULL);



while(true)

{

int n = 0;

if( 0 == (n =
recv(connfd,
buffRecv, MAXLINE,0)) )

{

printf("recv failed, Error Code: %d",
WSAGetLastError());

break;

}

buffRecv[n] = 0;
//
CallPython(buffRecv);

if( 0 == (n =
send(connfd,
buffRecv, strlen(buffRecv),0)) )

{

printf("send failed, Error Code: %d",
WSAGetLastError());

break;


}


fputs(buffRecv,
stdout);

}


closesocket(connfd);
}



客户端：
#include
"Winsock2.h"
#include
"errno.h"
#include
"stdlib.h"

#define
MAXLINE 1000
void
str_cli(FILE *fp,
SOCKET sockfd)
{

char sendline[MAXLINE] = {0};

char recvline[MAXLINE] = {0};

while ( (fgets(sendline,
MAXLINE, fp)) !=
NULL)

{


if(SOCKET_ERROR ==
send(sockfd,
sendline, strlen(sendline), 0))

{

printf("send failed, Error Code: %d",
WSAGetLastError());

break ;

}

}

closesocket(sockfd);
}
int
main(int
argc, char **argv)
{

WORD wVersionRequested = 0;

WSADATA wsaData;

int err;


wVersionRequested =
MAKEWORD( 2, 2 );


// windows下此初始化为必须，实际包含加载WinsockDLL的过程

err = WSAStartup(
wVersionRequested, &wsaData );

if ( err != 0 ) {

return -1;

}

SOCKET
sockfd;

struct sockaddr_in
servaddr;


if (argc != 2)

{

printf("usage: tcpcli <IPaddress>");

exit(1);

}


sockfd = socket(AF_INET,
SOCK_STREAM, 0);


ZeroMemory(&servaddr,
sizeof(servaddr));

servaddr.sin_family =
AF_INET;

servaddr.sin_port =
htons(13);

servaddr.sin_addr.s_addr =
inet_addr(argv[1]);


if( SOCKET_ERROR ==
connect(sockfd, (struct
sockaddr *) &servaddr,
sizeof(servaddr)))

{

printf("connet failed, Error Code: %d",
WSAGetLastError());

closesocket(sockfd);

return -1;

}


str_cli(stdin,
sockfd);
/* do it all */


system("pause");

exit(0);
}


就是运行的那么正常-_-!给我个解释？。。。。。另外，虽然做了写了好几个服务器了，我最近才知道。。原来。。。recv,send本来就是标准的套接口API。。。。我一直以为这些都是windows扩展的-_-!《Unix
Network Programming》书以前只看了前面一点，因为前面用的都是read,write接口来写套接字，所以嘛。。。呵呵，误解了，以前还常喊windows下用的recv,send很奇怪呢-_-!太无知了，所以嘛，还是要好好学习底层知识才行。。。不能太依赖于公司的网络框架了，虽然那个框架写的真是不赖。。。好用的很。。。
有在Ubuntu 8.04版本上成功accept的兄弟，请告知怎么样配置的。。。。

以此纪念刚开始在linux上学习网络编程的失败-_-!

--
最后的结果是客户端版本的ubuntu上测试成功-_-!


write by
九天雁翎(JTianLing) -- blog.csdn.net/vagrxie