Download Design

大型应用软件中期报告
——TCP/IP协议模拟
5060369032夏业添
5060369033蔡欣磊
5060369034陈君惠
5060369044钱晓骏
当前进度
详细设计阶段
尚未进入编码阶段
IP模块设计
ipaddr.h
IPv4地址结构
struct in_addr{
//Temporary ipv4 address,32 bits
unsigned char part[4];
};
字符串与ip地址转换函数
int inet_aton(const char *strptr,struct in_addr
*addrptr);
char *inet_ntoa(char *strptr,struct in_addr inaddr);
myip.h
IPv4头部
struct iphdr{
struct in_addr des;
struct in_addr src;
struct ip_info{
//should be 4-bit version
int ip_ver:4;
//should be 4-bit length of header
int ip_hl:4;
};
//should be 8-bit type of serve
unsigned char ip_tos;
//should be 16-bit length of the whole ip packet
unsigned short ip_len;
//should be 16-bit identification
unsigned short ip_id;
//should be 8-bit ttl
unsigned char ip_ttl;
//should be 8-bit protocal
unsigned char ip_pro;
//should be 8-bit ip header checksum
unsigned char ip_sum;
};
myip.h
/* this function send "ip package" to the virtual ip pipe
* Parameter:
* pheader:a pointer to the ip header of the package
* ptcpheader:a pointer to the tcp header which the packge
contains
* buf:a buffer which contains data
* buflen:the length of buffer
* Return Values:
* it returns -1 for some error,and 0 is returned if succeed
*/
int ip_output(struct iphdr *pheader,struct tcphdr
*ptcpheader,char *buf,int buflen);
myip.h
/* this function handle ip package which is recieved from the
* virtual ip tunnel
* Parameter:
* its parameter should be related to the implement of our
* tcp/ip simulation.So we will discuss it in some time.
* Return values:
* it returns -1 for some error,and 0 is returned if succeed
*/
int ip_input();
myip.h
/* this function calculates the check sum of a ip
header
* Parameter:
* pheader:a pointer to the ip header
* Return Values:
* it returns the calculated check_sum of a ip header
*/
unsigned ip_cal_sum(struct iphdr *pheader);
myip.h
/* this function check the check sum of a ip header
* Parameter:
* pheader:a pointer to the ip header
* Return Values:
* it returns -1 if the check sum is wrong,and 0 is
returned
* if correct.
*/
int ip_check_sum(struct iphdr *pheader);
tcp模块
mytcpstate.h
enum {
TCP_ESTABLISHED = 1,
TCP_SYN_SENT,
TCP_SYN_RECV,
TCP_FIN_WAIT1,
TCP_FIN_WAIT2,
TCP_TIME_WAIT,
TCP_CLOSE,
TCP_CLOSE_WAIT,
TCP_LAST_ACK,
TCP_LISTEN,
TCP_CLOSING,
/* Now a valid state */
TCP_MAX_STATES /* Leave at the end! */
};
mytcp.h
struct tcphdr{
//should be 16-bit source port
unsigned short tcp_sport;
//should be 16-bit destination port
unsigned short tcp_dport;
//should be 32-bit sequence number
unsigned long tcp_seq;
//should be 32-bit acknowledge number
unsigned long tcp_ack;
struct tcp_hl{
//should be 4-bit length of tcp header
unsigned char hl:4;
unsigned char :4;
};
struct tcp_flag{
unsigned char :2;
unsigned char urg:1;
unsigned char ack:1;
unsigned char psh:1;
unsigned char rst:1;
unsigned char syn:1;
unsigned char fin:1;
};
//should be 16-bit window size
unsigned short tcp_win;
//should be 16-bit checksum
unsigned short tcp_sum;
//should be 16-bit urgent pointer
//but in our design, it should always 0
unsigned short tcp_up;
};
tcp头文件
mytcp.h
ip伪头部
struct ip_fake_hdr{
struct in_addr des;
/*destination ip address*/
struct in_addr src;
/*source ip address*/
unsigned char mbz;
};
/*null*/
unsigned char pro;
/*protocal*/
unsigned short tcp_l
/*length of tcp package*/
mytcp.h
tcp控制块
struct tcpcb{
pid_t pid;
/*pid of associated
process*/
int sock;
/*socket of associated*/
int tcp_state; /*the state of tcp*/
struct tcpcb *next;
int timer[4];
unsigned short port;
};
/*a header of tcpcb list*/
struct tcpcb *head;
mytcp.h
/* this function send tcp data to ip layer.it will change
* tcp_state in tcpcb if some condition is satisfied.
* Parameter:
* ptcpheader:a pointer to the tcp header which the packge
contains
* buf:a buffer which contains data
* buflen:the length of buffer
* Return Values:
* it returns -1 for some error,and 0 is returned if succeed
*/
int tcp_output(struct tcphdr *ptcpheader,char *buf,len buflen);
mytcp.h
/* this function handles tcp data which is received from ip
* layer, it should check these data, make sure check_sum as
* well as and sequence is right and send data to user level.
* it will change tcp_state in tcpcb if some condition is
* satisfied.
* Parameter:
* its parameter should be related to the implement of our
* tcp/ip simulation.So we will discuss it in some time.
* Return values:
* it returns -1 for some error,and 0 is returned if succeed
*/
int tcp_input();
mytcp.h
/* this function watches all the network timers which is in
* every tcpcb nodes.when a time out is happen, it will handle
* the work to tell user(socket).It wakes up in every servral
* secones,and then reduce tcpcb timers in every tcpcb.
* when a timer reduces to 0, it means some work is time out.
* it will change tcp_state in tcpcb if some condition is
* satisfied.
*/
int tcp_timer();
mytcp.h
/* this function check a tcp check sum whether is correct.
* Parameter:
* its parameter should be related to the implement of our
* tcp/ip simulation.So we will discuss it in some time.
* Return Values:
* it returns -1 if the check sum is wrong, and 0 is returned
* if correct.
*/
int tcp_checksum();
mytcp.h
/* this function create a new tcpcb nodes.
* Parameter:
* some elements in struct tcpcb is not decided, this
part should
* be determined when struct tcpcb is certain.
* Return Values:
* it will return a NULL pointer if creation is failed,
and a
* pointer to the new tcpcb is returned if succeed.
*/
struct tcpcb* tcp_new_tcpcb();
socket模块
mysocket.h
struct sockaddr{
struct in_addr sin_addr;
unsigned short sin_port;
};
//we should discuss this
struct socket{
};
mysocket.h
int socket();
int close(int sockfd);
int read(int sockfd,char *buf,int bufsize);
int write(int sockfd,char *buf,int buflen);
int bind(int sockfd,const struct sockaddr
*myaddr,int addrlen);
int connect(int sockfd,const struct sockaddr
*servaddr,int addrlen);
int listen(int sockfd,int backlog);
int accept(int sockfd,struct sockaddr *cliaddr,int
*addrlen);
tcpipsim.h
tcpipsim.h
/* this function initialize our tcp/ip stack
* at least it should include:
* 1.show its pid
* 2.set another tcp/ip stack ip-pid pair(ip route)
* Return Values:
* it returns -1 for some error,and 0 is returned if
succeed
*/
int init();
tcpipsim.h
/* this function handle tcp timer.it calls tcp_timer() to
* achieve its goals
*/
void timer_thread_handler();
/* this function handle network stuff.
* All network activities, such as sending/recieving package,
* changing tcp state and interactive works with users,should
* be under its control.
*/
void network_thread_handler();
msgtype.h
enum {
MSG_IP_TUNNEL=1,
MSG_USR_READ,
MSG_USR_WRITE,
MSG_USR_CLOSE,
MSG_USR_BIND,
network_thread_handler.c
等待消息，做出反应
switch(msg){
case MSG_IP_TUNNEL
//ip_input()
break;
case MSG_USR_WRITE
tcp_output();
break;
...
case MSG_USR_CONNECT
tcp_output();
break;
}
这样的结构
timer_handler.c
while(1）{
//wake up every a seconds
select(NULL,NULL,NULL,&timeout);
遍历链表，计时器-1
若有<0的计时器说明超时，进行处理
}
THANK YOU!