• day37:网编day4，多点通信和并发服务器

    一、广播接收方：

    1. #include <myhead.h>
    2.  
    3. #define ERR_MSG(msg) do{\
    4. fprintf(stderr,"__%d__\n",__LINE__);\
    5. perror(msg);\
    6. }while(0)
    7.  
    8. #define BRD_IP "192.168.114.255"
    9. #define BRD_PORT 8888
    10.  
    11. int main(int argc, const char *argv[])
    12. {
    13. 	//创建报式套接字
    14. 	int sfd = -1;
    15. 	if((sfd = socket(AF_INET,SOCK_DGRAM,0)) < 0)
    16. 	{
    17. 		ERR_MSG("socket");
    18. 	}
    19. 	printf("socket success sfd=%d\n",sfd);
    20.  
    21. 	//填充地址信息结构体给bind用
    22. 	struct sockaddr_in sin;
    23. 	sin.sin_family = AF_INET; 	//必须填AF_INET
    24. 	sin.sin_port = htons(BRD_PORT); 	//广播端口号
    25. 	sin.sin_addr.s_addr = inet_addr(BRD_IP); 	//广播IP
    26. 	//bind绑定地址信息
    27. 	if(bind(sfd,(struct sockaddr*)&sin,sizeof(sin)) < 0)
    28. 	{
    29. 		ERR_MSG("bind");
    30. 		return -1;
    31. 	}
    32. 	printf("bind success[%s:%d]\n",BRD_IP,BRD_PORT);
    33. 	
    34. 	socklen_t addrlen = sizeof(sin);
    35. 	char buf[128]="";
    36. 	ssize_t len;
    37. 	while(1)
    38. 	{
    39. 		if((len = recvfrom(sfd,buf,sizeof(buf),0,(struct sockaddr*)&sin,&addrlen)) < 0)
    40. 		{
    41. 			ERR_MSG("recvfrom");
    42. 			return -1;
    43. 		}
    44. 		printf("recvfrom success %s\n",buf);
    45. 	}
    46. 	close(sfd);
    47. 	return 0;
    48. }

    二、广播发送方：

    1. #include <myhead.h>
    2.  
    3. #define ERR_MSG(msg) do{\
    4. fprintf(stderr,"__%d__\n",__LINE__);\
    5. perror(msg);\
    6. }while(0)
    7.  
    8. #define BRD_IP "192.168.114.255"
    9. #define BRD_PORT 8888
    10.  
    11. int main(int argc, const char *argv[])
    12. {
    13. 	//创建报式套接字
    14. 	int cfd = -1;
    15. 	if((cfd = socket(AF_INET,SOCK_DGRAM,0)) < 0)
    16. 	{
    17. 		ERR_MSG("socket");
    18. 	}
    19. 	printf("socket success cfd=%d\n",cfd);
    20. 	
    21. 	int broad = 1;
    22. 	if(setsockopt(cfd,SOL_SOCKET,SO_BROADCAST,(int*)&broad,sizeof(broad)) < 0)
    23. 	{
    24. 		ERR_MSG("setsockpot");
    25. 		return-1;
    26. 	}
    27. 	printf("setsockpot success\n");
    28. 	//非必须绑定
    29. 	//填充地址信息结构体给sendto
    30. 	struct sockaddr_in sin;
    31. 	sin.sin_family = AF_INET; 	//必须填AF_INET
    32. 	sin.sin_port = htons(BRD_PORT); 	//广播端口号
    33. 	sin.sin_addr.s_addr = inet_addr(BRD_IP); 	//广播IP
    34. 	printf("bind success[%s:%d]\n",BRD_IP,BRD_PORT);
    35. 	
    36. 	char buf[128]="";
    37. 	ssize_t len;
    38. 	while(1)
    39. 	{
    40. 		//清空buf
    41. 		bzero(buf,sizeof(buf));
    42.  
    43. 		//从终端输入数据保存到buf中
    44. 		fscanf(stdin,"%s",buf);
    45. 		while(getchar()!=10);
    46.  
    47. 		if(sendto(cfd,buf,strlen(buf),0,(struct sockaddr*)&sin,sizeof(sin)) < 0)
    48. 		{
    49. 			ERR_MSG("sendto");
    50. 			return -1;
    51. 		}
    52. 		printf("sendto success\n");
    53. 	}
    54. 	close(cfd);
    55. 	return 0;
    56. }

    三、组播接收方：

    1. #include <myhead.h>
    2.  
    3. #define ERR_MSG(msg) do{\
    4. fprintf(stderr,"__%d__\n",__LINE__);\
    5. perror(msg);\
    6. }while(0)
    7.  
    8. #define GRP_IP "224.1.2.3" 	//组播IP
    9. #define IP "192.168.114.94" //本机IP
    10. #define GRP_PORT 8888
    11.  
    12. int main(int argc, const char *argv[])
    13. {
    14. 	//创建报式套接字
    15. 	int sfd = -1;
    16. 	if((sfd = socket(AF_INET,SOCK_DGRAM,0)) < 0)
    17. 	{
    18. 		ERR_MSG("socket");
    19. 	}
    20. 	printf("socket success sfd=%d\n",sfd);
    21.  
    22. 	//填充结构体，来完成组播连接
    23. 	struct ip_mreqn grp;
    24. 	grp.imr_multiaddr.s_addr = inet_addr(GRP_IP); //组播IP
    25. 	grp.imr_address.s_addr = inet_addr(IP); //本机IP
    26. 	grp.imr_ifindex = 0; //自动
    27.  
    28. 	//设置连接组播
    29. 	if(setsockopt(sfd,IPPROTO_IP,IP_ADD_MEMBERSHIP,&grp,sizeof(grp)) < 0)
    30. 	{
    31. 		ERR_MSG("setsockopt");
    32. 		return -1;
    33. 	}
    34. 	printf("setsockopt success\n");
    35.  
    36. 	//填充地址信息结构体给bind用
    37. 	struct sockaddr_in sin;
    38. 	sin.sin_family = AF_INET; 	//必须填AF_INET
    39. 	sin.sin_port = htons(GRP_PORT); 	//组播端口号
    40. 	sin.sin_addr.s_addr = inet_addr(GRP_IP); 	//组播IP
    41. 	//bind绑定地址信息
    42. 	if(bind(sfd,(struct sockaddr*)&sin,sizeof(sin)) < 0)
    43. 	{
    44. 		ERR_MSG("bind");
    45. 		return -1;
    46. 	}
    47. 	printf("bind success[%s:%d]\n",GRP_IP,GRP_PORT);
    48. 	
    49. 	socklen_t addrlen = sizeof(sin);
    50. 	char buf[128]="";
    51. 	ssize_t len;
    52. 	while(1)
    53. 	{
    54. 		if((len = recvfrom(sfd,buf,sizeof(buf),0,(struct sockaddr*)&sin,&addrlen)) < 0)
    55. 		{
    56. 			ERR_MSG("recvfrom");
    57. 			return -1;
    58. 		}
    59. 		printf("recvfrom success %s\n",buf);
    60. 	}
    61. 	close(sfd);
    62. 	return 0;
    63. }

    四、组播发送方：

    1. #include <myhead.h>
    2.  
    3. #define ERR_MSG(msg) do{\
    4. fprintf(stderr,"__%d__\n",__LINE__);\
    5. perror(msg);\
    6. }while(0)
    7.  
    8. #define BRD_IP "224.1.2.3"
    9. #define BRD_PORT 8888
    10.  
    11. int main(int argc, const char *argv[])
    12. {
    13. 	//创建报式套接字
    14. 	int cfd = -1;
    15. 	if((cfd = socket(AF_INET,SOCK_DGRAM,0)) < 0)
    16. 	{
    17. 		ERR_MSG("socket");
    18. 	}
    19. 	printf("socket success cfd=%d\n",cfd);
    20. 	
    21. 	int broad = 1;
    22. 	if(setsockopt(cfd,SOL_SOCKET,SO_BROADCAST,(int*)&broad,sizeof(broad)) < 0)
    23. 	{
    24. 		ERR_MSG("setsockpot");
    25. 		return-1;
    26. 	}
    27. 	printf("setsockpot success\n");
    28. 	//非必须绑定
    29. 	//填充地址信息结构体给sendto
    30. 	struct sockaddr_in sin;
    31. 	sin.sin_family = AF_INET; 	//必须填AF_INET
    32. 	sin.sin_port = htons(BRD_PORT); 	//广播端口号
    33. 	sin.sin_addr.s_addr = inet_addr(BRD_IP); 	//广播IP
    34. 	printf("bind success[%s:%d]\n",BRD_IP,BRD_PORT);
    35. 	
    36. 	char buf[128]="";
    37. 	ssize_t len;
    38. 	while(1)
    39. 	{
    40. 		//清空buf
    41. 		bzero(buf,sizeof(buf));
    42.  
    43. 		//从终端输入数据保存到buf中
    44. 		fscanf(stdin,"%s",buf);
    45. 		while(getchar()!=10);
    46.  
    47. 		if(sendto(cfd,buf,strlen(buf),0,(struct sockaddr*)&sin,sizeof(sin)) < 0)
    48. 		{
    49. 			ERR_MSG("sendto");
    50. 			return -1;
    51. 		}
    52. 		printf("sendto success\n");
    53. 	}
    54. 	close(cfd);
    55. 	return 0;
    56. }

    五、TCP多线程并发服务器：

    1. #include <myhead.h>
    2.  
    3. #define ERR_MSG(msg) do{\
    4. 	fprintf(stderr,"__%d__\n",__LINE__);\
    5. 	perror(msg);\
    6. }while(0)
    7.  
    8. #define IP "192.168.114.94"
    9. #define PORT 8888
    10.  
    11. int del_cli_msg(int newfd,struct sockaddr_in cin);
    12. void handler(int num)
    13. {
    14. 	if(num == SIGCHLD)
    15. 	{
    16. 		while(waitpid(-1,NULL,WNOHANG) > 0);
    17. 	}
    18. }
    19. int main(int argc, const char *argv[])
    20. {
    21. 	if(signal(SIGCHLD,handler) == SIG_ERR)
    22. 	{
    23. 		ERR_MSG("signal");
    24. 		return -1;
    25. 	}
    26. 	printf("signal success\n");
    27. 	//创建流式套接字
    28. 	int sfd = -1;
    29. 	if((sfd = socket(AF_INET,SOCK_STREAM,0)) < 0)
    30. 	{
    31. 		ERR_MSG("socket");
    32. 		return -1;
    33. 	}
    34. 	printf("socket success sfd = %d\n",sfd);
    35.  
    36.     //允许端口快速的被复用
    37.     int reuse = 1;                                                            
    38.     if(setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse)) < 0)
    39.     {
    40.         ERR_MSG("setsockopt");
    41.         return -1;
    42.     }
    43.     printf("允许端口快速的被复用成功\n");	//填充地址信息结构体给bind使用
    44.  
    45. 	struct sockaddr_in sin;
    46. 	sin.sin_family = AF_INET;
    47. 	sin.sin_port = htons(PORT); 	//服务器端口号
    48. 	sin.sin_addr.s_addr = inet_addr(IP); 	//服务器IP
    49. 	//bind必须绑定IP和端口号
    50. 	if(bind(sfd,(struct sockaddr*)&sin,sizeof(sin)) < 0)
    51. 	{
    52. 		ERR_MSG("bind");
    53. 		return -1;
    54. 	}
    55. 	printf("bind success [%s:%d]\n",IP,PORT);
    56. 	//listen把sfd切换成监听模式
    57. 	if(listen(sfd,128) < 0)
    58. 	{
    59. 		ERR_MSG("listen");
    60. 		return -1;
    61. 	}
    62. 	printf("listen success sfd = %d\n",sfd);
    63. 	struct sockaddr_in cin;
    64. 	socklen_t addrlen=sizeof(cin);
    65. 	int newfd =-1;
    66. 	pid_t pid;
    67. 	while(1)
    68. 	{
    69. 		//accept接收客户端发送过来的地址信息，创建一个newfd与其通讯accept
    70. 		//父进程专门负责连接
    71. 		if((newfd = accept(sfd,(struct sockaddr*)&cin,&addrlen)) < 0)
    72. 		{
    73. 			ERR_MSG("accept");
    74. 			return -1;
    75. 		}
    76. 		printf("[%s:%d]客户端连接成功 newfd = %d\n",\
    77. 				inet_ntoa(cin.sin_addr),ntohs(cin.sin_port),newfd);
    78. 		pid = fork();
    79. 		if(0 == pid)
    80. 		{
    81. 			close(sfd);
    82. 			//子进程专门负责交互
    83. 			del_cli_msg(newfd,sin);
    84. 			exit(0);
    85. 		}
    86. 		close(newfd);
    87. 	}
    88. 	close(sfd);
    89. 	return 0;
    90. }
    91. int del_cli_msg(int newfd,struct sockaddr_in cin)
    92. {
    93. 	char buf[128] ="";
    94. 	ssize_t len = 0;
    95. 	while(1)
    96. 	{
    97. 		bzero(buf,sizeof(buf));
    98. 		len = recv(newfd,buf,sizeof(buf),0);
    99. 		if(len< 0)
    100. 		{
    101. 			ERR_MSG("recvfrom");
    102. 			return -1;
    103. 		}
    104. 		else if(len == 0)
    105. 		{
    106. 			printf("[%s:%d]客户端已下线 newfd = %d\n",\
    107. 					inet_ntoa(cin.sin_addr),ntohs(cin.sin_port),newfd);
    108. 			break;
    109. 		}
    110. 		printf("recv success [%s:%d],newfd=%d buf=%s\n",\
    111. 				inet_ntoa(cin.sin_addr),ntohs(cin.sin_port),newfd,buf);
    112. 		/*
    113. 		bzero(buf,sizeof(buf));
    114. 		printf("请输入数据发送给客户端");
    115. 		fscanf(stdin,"%s",buf);
    116. 		while(getchar()!=10);
    117. 		*/
    118. 		strcat(buf,">-<");
    119. 		if(send(newfd,buf,strlen(buf),0) < 0)
    120. 		{
    121. 			ERR_MSG("send");
    122. 			return -1;
    123. 		}
    124. 		printf("send success buf = %s\n",buf);
    125. 	}
    126. }

    六、TCP多线程并发服务器：

    1. #include <myhead.h>
    2.  
    3. #define ERR_MSG(msg) do{\
    4. 	fprintf(stderr,"__%d__\n",__LINE__);\
    5. 	perror(msg);\
    6. }while(0)
    7.  
    8. #define IP "192.168.114.94"
    9. #define PORT 8888
    10. struct Data
    11. {
    12. 	int newfd;
    13. 	struct sockaddr_in cin;
    14. };
    15. void *del_cli_msg(void *arg);
    16. int main(int argc, const char *argv[])
    17. {
    18. 	printf("signal success\n");
    19. 	//创建流式套接字
    20. 	int sfd = -1;
    21. 	if((sfd = socket(AF_INET,SOCK_STREAM,0)) < 0)
    22. 	{
    23. 		ERR_MSG("socket");
    24. 		return -1;
    25. 	}
    26. 	printf("socket success sfd = %d\n",sfd);
    27.  
    28.     //允许端口快速的被复用
    29.     int reuse = 1;                                                            
    30.     if(setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse)) < 0)
    31.     {
    32.         ERR_MSG("setsockopt");
    33.         return -1;
    34.     }
    35.     printf("允许端口快速的被复用成功\n");	//填充地址信息结构体给bind使用
    36.  
    37. 	struct sockaddr_in sin;
    38. 	sin.sin_family = AF_INET;
    39. 	sin.sin_port = htons(PORT); 	//服务器端口号
    40. 	sin.sin_addr.s_addr = inet_addr(IP); 	//服务器IP
    41. 	//bind必须绑定IP和端口号
    42. 	if(bind(sfd,(struct sockaddr*)&sin,sizeof(sin)) < 0)
    43. 	{
    44. 		ERR_MSG("bind");
    45. 		return -1;
    46. 	}
    47. 	printf("bind success [%s:%d]\n",IP,PORT);
    48. 	//listen把sfd切换成监听模式
    49. 	if(listen(sfd,128) < 0)
    50. 	{
    51. 		ERR_MSG("listen");
    52. 		return -1;
    53. 	}
    54. 	printf("listen success sfd = %d\n",sfd);
    55. 	struct sockaddr_in cin;
    56. 	socklen_t addrlen=sizeof(cin);
    57. 	int newfd =-1;
    58. 	pthread_t tid;
    59. 	while(1)
    60. 	{
    61. 		//accept接收客户端发送过来的地址信息，创建一个newfd与其通讯accept
    62. 		//父进程专门负责连接
    63. 		if((newfd = accept(sfd,(struct sockaddr*)&cin,&addrlen)) < 0)
    64. 		{
    65. 			ERR_MSG("accept");
    66. 			return -1;
    67. 		}
    68. 		printf("[%s:%d]客户端连接成功 newfd = %d\n",\
    69. 				inet_ntoa(cin.sin_addr),ntohs(cin.sin_port),newfd);
    70. 		struct Data data;
    71. 		data.newfd = newfd;
    72. 		data.cin = cin;
    73. 		if(pthread_create(&tid,NULL,del_cli_msg,&data))
    74. 		{
    75. 			printf("pthread_create error\n");
    76. 			return -1;
    77. 		}
    78. 		printf("create success\n");
    79. 		pthread_detach(tid);
    80. 	}
    81. 	close(sfd);
    82. 	return 0;
    83. }
    84. void *del_cli_msg(void *arg)
    85. {
    86. 	int newfd = ((struct Data*)arg)->newfd;
    87. 	struct sockaddr_in cin = ((struct Data*)arg)->cin;
    88. 	char buf[128] ="";
    89. 	ssize_t len = 0;
    90. 	while(1)
    91. 	{
    92. 		bzero(buf,sizeof(buf));
    93. 		len = recv(newfd,buf,sizeof(buf),0);
    94. 		if(len< 0)
    95. 		{
    96. 			ERR_MSG("recvfrom");
    97. 			break;
    98. 		}
    99. 		else if(len == 0)
    100. 		{
    101. 			printf("[%s:%d]客户端已下线 newfd = %d\n",\
    102. 					inet_ntoa(cin.sin_addr),ntohs(cin.sin_port),newfd);
    103. 			break;
    104. 		}
    105. 		printf("recv success [%s:%d],newfd=%d buf=%s\n",\
    106. 				inet_ntoa(cin.sin_addr),ntohs(cin.sin_port),newfd,buf);
    107. 		/*
    108. 		bzero(buf,sizeof(buf));
    109. 		printf("请输入数据发送给客户端");
    110. 		fscanf(stdin,"%s",buf);
    111. 		while(getchar()!=10);
    112. 		*/
    113. 		strcat(buf,">-<");
    114. 		if(send(newfd,buf,strlen(buf),0) < 0)
    115. 		{
    116. 			ERR_MSG("send");
    117. 			break;
    118. 		}
    119. 		//printf("send success buf = %s\n",buf);
    120. 	}
    121. }

    七、多线程并发服务器为什么不能将newfd定义成全局？

    不能，因为如果newfd设成全局变量，而多线程之间共享0-3G用户空间，临界资源，所以会导致newfd变化后，原先线程进行交互。

    八、基于UDP的TFTP文件传输，完成下载和上传功能，制作的是客户端，与tftp服务器进行交互

    1. #include <myhead.h>
    2.  
    3. #define ERR(s) do\
    4. {\
    5. 	fprintf(stderr,"__%d__",__LINE__);\
    6. 	perror(s);\
    7. }while(0)
    8. #define PORT 69
    9. #define IP "192.168.114.103"
    10.  
    11. int do_download(int cfd,struct sockaddr_in sin);
    12. int do_upload(int cfd,struct sockaddr_in sin);
    13. int main(int argc, const char *argv[])
    14. {
    15.  
    16. 	//创建报式套接字socket
    17. 	int cfd;
    18. 	if((cfd = socket(AF_INET,SOCK_DGRAM,0)) < 0)
    19. 	{
    20. 		ERR("socket");
    21. 		return -1;
    22. 	}
    23. 	printf("socket success\n");
    24.  
    25. 	struct sockaddr_in sin;
    26. 	sin.sin_family = AF_INET;
    27. 	sin.sin_port = htons(PORT);
    28. 	sin.sin_addr.s_addr = inet_addr(IP);
    29. 	char choose = 0;
    30. 	while(1)
    31. 	{
    32. 		system("clear");
    33. 		printf("--------------------------------\n");
    34. 		printf("-------------1下载--------------\n");
    35. 		printf("-------------2上传--------------\n");
    36. 		printf("-------------3退出--------------\n");
    37. 		printf("--------------------------------\n");
    38. 		printf("请输入>>>");
    39. 		scanf("%c",&choose);
    40. 		while(getchar()!=10); 	//吸收垃圾字符
    41. 		switch(choose)
    42. 		{
    43. 		case '1':
    44. 			do_download(cfd,sin);
    45. 			break;
    46. 		case '2':
    47. 			do_upload(cfd,sin);
    48. 			break;
    49. 		case '3':
    50. 			goto END;
    51. 			break;
    52. 		default :
    53. 			printf("输入错误，请重新输入\n");
    54. 		}
    55. 		printf("请输入任意字符清屏\n");
    56. 		while(getchar()!=10);
    57. 	}
    58. END:
    59. 	//关闭套接字
    60. 	close(cfd);
    61. 	return 0;
    62. }
    63.  
    64. int do_download(int cfd,struct sockaddr_in sin)
    65. {
    66. 	/*
    67. 	//组下载请求包
    68. 	char buf[516] = "";
    69. 	char f_n[20] = "";
    70. 	//操作码
    71. 	unsigned short *ptr1 = (unsigned short*)buf;
    72. 	 *ptr1 = htons(1); 	//组操作码
    73. 	//文件名
    74. 	char *ptr2 = (char *)(ptr1+1);
    75. 	strcpy(ptr2,f_n);
    76. 	//模式
    77. 	char *ptr3 = ptr2 + strlen(f_n) + 1;
    78. 	strcpy(ptr3,"octet");
    79.  
    80. 	int size = 2+strlen(ptr2)+1+strlen(ptr3)+1;
    81. 	*/
    82. 	char buf[516] = "";
    83. 	char f_n[20] = "";
    84. 	int num=1;
    85. 	printf("请输入文件名>>> ");
    86. 	//终端输入要下载的文件名
    87. 	fgets(f_n,sizeof(f_n),stdin);
    88. 	f_n[strlen(f_n)-1] = '\0';
    89. 	int fd;
    90. 	if((fd = open(f_n,O_RDONLY|O_CREAT|O_TRUNC,0664)) == -1)
    91. 	{
    92. 		ERR("open");
    93. 		return -1;
    94. 	}
    95. 	//用sprintf拼接
    96. 	int size = sprintf(buf,"%c%c%s%c%s%c",0,1,f_n,0,"octet",0);
    97. 	//发送下载请求sendto
    98. 	if(sendto(cfd,buf,size,0,(struct sockaddr*)&sin,sizeof(sin)) < 0 )
    99. 	{
    100. 		ERR("sendto askpackage");
    101. 		return -1;
    102. 	}
    103. 	printf("sendto askpackage success\n");
    104. 	ssize_t len = -1;
    105. 	struct sockaddr_in addrin;
    106. 	socklen_t addrlen=sizeof(addrin);
    107. 	while(1)
    108. 	{
    109. 		//清空buf
    110. 		bzero(buf,sizeof(buf));
    111. 		//接收数据recvfrom，接收地址信息
    112. 		if((len = recvfrom(cfd,buf,sizeof(buf),0,(struct sockaddr*)&addrin,&addrlen)) < 0)
    113. 		{
    114. 			ERR("recvfrom datapackage");
    115. 			return -1;
    116. 		}
    117. 		unsigned short ptr2=ntohs(*(unsigned short*)(buf+2));
    118. 		printf("%hu\n",ptr2);	
    119. 		//当操作码为5时
    120. 		if(5 == buf[1])
    121. 		{
    122. 			fprintf(stderr, "错误码：%d，错误信息：%s\n", ntohs(*(unsigned short*)(buf+2)), buf+4);			
    123. 			break;
    124. 		}
    125. 		//当操作码为3,并且块编号正确时
    126. 		else if(3 == buf[1] && num == ptr2)
    127. 		{
    128. 			printf("%d\n",fd);
    129. 			//跳过前四个字节，写入文件
    130.  
    131. 			if(write(fd,buf+4,len-4)<0)
    132. 			{
    133. 				ERR("write");
    134. 				return -1;
    135. 			}
    136.  
    137. 			//组ACK包
    138. 			buf[1] = 4;	
    139. 			//发送ACK包，sendto
    140. 			if(sendto(cfd,buf,4,0,(struct sockaddr*)&addrin,addrlen) < 0)
    141. 			{
    142. 				ERR("sendto ACKpackage");
    143. 				return -1;
    144. 			}
    145. 			num++;
    146. 			//判断数据是否小于512个字节，若小于则下载完成
    147. 			if(len < 516)
    148. 			{
    149. 				printf("download success\n");
    150. 				break;
    151. 			}
    152. 		}
    153. 	}
    154. 	close(fd);
    155. 	return 0;
    156. }
    157.  
    158. int do_upload(int cfd,struct sockaddr_in sin)
    159. {
    160. 	char f_n[20]="";
    161. 	printf("请输入传输文件名>>>");
    162. 	fscanf(stdin,"%s",f_n);
    163. 	while(getchar()!=10);
    164.  
    165. 	//打开文件
    166. 	int srcfd = -1;
    167. 	if((srcfd = open(f_n,O_RDONLY)) < 0)
    168. 	{
    169. 		if(errno == ENOENT)
    170. 		{
    171. 			printf("文件不存在，请重新输入>>>");
    172. 			return -2;
    173. 		}
    174. 		else
    175. 		{
    176. 			ERR("open srcfile");
    177. 			return -1;
    178. 		}
    179. 	}
    180.  
    181. 	char buf[516]="";
    182. 	//用sprintf拼接读写请求封包
    183. 	int size=sprintf(buf,"%c%c%s%c%s%c",0,2,f_n,0,"octet",0);
    184. 	if(sendto(cfd,buf,size,0,(struct sockaddr*)&sin,sizeof(sin)) < 0)
    185. 	{
    186. 		ERR("sendto askpackage");
    187. 		return -1;
    188. 	}
    189. 	printf("sendto askpackage success\n");
    190.  
    191.  
    192. 	//记录块编号
    193. 	int num=0;
    194. 	unsigned short* ptr = (unsigned short *)(buf+2);
    195. 	//记录我要传过去数据的大小
    196. 	ssize_t len = -1;
    197. 	socklen_t addrlen = sizeof(sin);
    198. 	while(1)
    199. 	{
    200. 		bzero(buf,sizeof(buf));
    201. 		//接受ACK
    202. 		if(recvfrom(cfd,buf,sizeof(buf),0,(struct sockaddr*)&sin,&addrlen) < 0)
    203. 		{
    204. 			ERR("recvfrom ACKpackage");
    205. 			return -1;
    206. 		}
    207. 		printf("recvfrom ACKpackage success\n");
    208. 		//当传过来的是ACK并且对应的块编号是需要的块编号时
    209. 		if(buf[1] == 4)
    210. 		{
    211. 			if(*ptr == htons(num))
    212. 			{
    213. 				num++;
    214. 				//把操作码改为3，向服务器发送数据
    215. 				buf[1] = 3;
    216. 				//*(unsigned short *)(buf+2)= htons(num);
    217. 				*ptr = htons(num);
    218. 				//从文件中读取数据，保存到buf中
    219. 				len = read(srcfd,buf+4,sizeof(buf)-4);
    220. 				if(len < 0)
    221. 				{
    222. 					ERR("read srcfd");
    223. 					return -1;
    224. 				}
    225. 				else if(0 == len)
    226. 				{
    227. 					printf("文件上传完毕\n");
    228. 					break;
    229. 				}
    230. 				//向服务器发送打包好的数据包
    231. 				if(sendto(cfd,buf,len+4,0,(struct sockaddr*)&sin,addrlen) < 0)
    232. 				{
    233. 					ERR("sendto datapackage");
    234. 					return -1;
    235. 				}
    236. 				printf("sendto datapackage success\n");
    237. 			}else{
    238. 				printf("网络不好，上传数据失败\n");
    239. 				break;
    240. 			}
    241. 		}
    242. 		else if(buf[1] == 5)
    243. 		{
    244. 			fprintf(stderr,"错误码：%d，错误信息：%s\n",\
    245. 					ntohs(*(unsigned short*)(buf+2)),buf+4);
    246. 			break;
    247. 		}
    248. 	}
    249.  
    250. 	return 0;
    251. }

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  • 原文地址：https://blog.csdn.net/wxmchong/article/details/132590889