Makefile文件:   Makefile
	主文件:   cproxy.c
This commit is contained in:
aixiao 2018-08-22 11:16:16 +00:00
commit 8fb56a9b57
2 changed files with 456 additions and 0 deletions

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Makefile Normal file
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CC = gcc
CFLAGS = -g -Wall -Werror
all: cproxy
cproxy: cproxy.o
$(CC) $(CFLAGS) cproxy.o -o cproxy
cproxy.o:
$(CC) $(CFLAGS) -c cproxy.c
clean:
rm -rf *.o
rm cproxy

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cproxy.c Normal file
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#include <arpa/inet.h>
#include <errno.h>
#include <libgen.h>
#include <netdb.h>
#include <resolv.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#include <sys/wait.h>
#include <netinet/in.h>
#define BUF_SIZE 8192
#define PORT 9606
#define MAX_HEADER_SIZE 8192
char remote_host[128];
int remote_port;
int local_port;
int server_sock;
int client_sock;
int remote_sock;
char * header_buffer ;
enum
{
FLG_NONE = 0, // 正常数据流不进行编解码
R_C_DEC = 1, // 读取客户端数据仅进行解码
W_S_ENC = 2 // 发送到服务端进行编码
};
static int io_flag; // 网络io的一些标志位
void handle_client(int client_sock, struct sockaddr_in client_addr);
void forward_header(int destination_sock);
void forward_data(int source_sock, int destination_sock);
void rewrite_header();
int send_data(int socket,char * buffer,int len );
int receive_data(int socket, char * buffer, int len);
void hand_mproxy_info_req(int sock,char * header_buffer) ;
int create_connection() ;
int _main(int argc, char *argv[]) ;
ssize_t readLine(int fd, void *buffer, size_t n)
{
ssize_t numRead;
size_t totRead;
char *buf;
char ch;
if (n <= 0 || buffer == NULL) {
errno = EINVAL;
return -1;
}
buf = buffer;
totRead = 0;
for (;;) {
numRead = receive_data(fd, &ch, 1);
if (numRead == -1) {
if (errno == EINTR)
continue;
else
return -1; // 未知错误
} else if (numRead == 0) { // EOF
if (totRead == 0) // No bytes read; return 0
return 0;
else // Some bytes read; add '\0'
break;
} else {
if (totRead < n - 1) { // Discard > (n - 1) bytes
totRead++;
*buf++ = ch;
}
if (ch == '\n')
break;
}
}
*buf = '\0';
return totRead;
}
int read_header(int fd, void * buffer)
{
memset(header_buffer,0,MAX_HEADER_SIZE);
char line_buffer[2048];
char * base_ptr = header_buffer;
for(;;)
{
memset(line_buffer,0,2048);
int total_read = readLine(fd,line_buffer,2048);
if(total_read <= 0)
{
return -1;
}
// 防止header缓冲区蛮越界
if(base_ptr + total_read - header_buffer <= MAX_HEADER_SIZE)
{
strncpy(base_ptr,line_buffer,total_read);
base_ptr += total_read;
} else
{
return -1;
}
// 读到了空行http头结束
if(strcmp(line_buffer,"\r\n") == 0 || strcmp(line_buffer,"\n") == 0)
{
break;
}
}
return 0;
}
void extract_server_path(const char * header,char * output)
{
char * p = strstr(header,"GET /");
if(p) {
char * p1 = strchr(p+4,' ');
strncpy(output,p+4,(int)(p1 - p - 4) );
}
}
int extract_host(const char * header)
{
char * _p = strstr(header,"CONNECT"); // 在 CONNECT 方法中解析 隧道主机名称及端口号
if(_p)
{
char * _p1 = strchr(_p,' ');
char * _p2 = strchr(_p1 + 1,':');
char * _p3 = strchr(_p1 + 1,' ');
if(_p2)
{
char s_port[10];
bzero(s_port,10);
strncpy(remote_host,_p1+1,(int)(_p2 - _p1) - 1);
strncpy(s_port,_p2+1,(int) (_p3 - _p2) -1);
remote_port = atoi(s_port);
} else
{
strncpy(remote_host,_p1+1,(int)(_p3 - _p1) -1);
remote_port = 80;
}
return 0;
}
char * p = strstr(header,"Host:");
if(!p)
{
return -1;
}
char * p1 = strchr(p,'\n');
if(!p1)
{
return -1;
}
char * p2 = strchr(p + 5,':'); // 5是指'Host:'的长度
if(p2 && p2 < p1)
{
int p_len = (int)(p1 - p2 -1);
char s_port[p_len];
strncpy(s_port,p2+1,p_len);
s_port[p_len] = '\0';
remote_port = atoi(s_port);
int h_len = (int)(p2 - p -5 -1 );
strncpy(remote_host,p + 5 + 1 ,h_len); // Host:
remote_host[h_len] = '\0';
} else
{
int h_len = (int)(p1 - p - 5 -1 -1);
strncpy(remote_host,p + 5 + 1,h_len);
remote_host[h_len] = '\0';
remote_port = 80;
}
return 0;
}
// 响应隧道连接请求
int send_tunnel_ok(int client_sock)
{
char * resp = "HTTP/1.1 200 Connection Established\r\n\r\n";
int len = strlen(resp);
char buffer[len+1];
strcpy(buffer,resp);
if(send_data(client_sock,buffer,len) < 0)
{
return -1;
}
return 0;
}
void hand_mproxy_info_req(int sock, char * header) {
char server_path[255] ;
char response[8192];
extract_server_path(header,server_path);
char info_buf[1024];
sprintf(response,"HTTP/1.0 200 OK\nServer: CProxy/0.1\n\
Content-type: text/html; charset=utf-8\n\n\
<html><body>\
<pre>%s</pre>\
</body></html>\n",info_buf);
write(sock,response,strlen(response));
}
// 处理客户端的连接
void handle_client(int client_sock, struct sockaddr_in client_addr)
{
int is_http_tunnel = 0;
if(strlen(remote_host) == 0) // 未指定远端主机名称从http 请求 HOST 字段中获取
{
if(read_header(client_sock,header_buffer) < 0)
{
return;
} else
{
char * p = strstr(header_buffer,"CONNECT"); // 判断是否是http 隧道请求
if(p)
{
is_http_tunnel = 1;
}
if(strstr(header_buffer,"GET /cproxy") > 0)
{
hand_mproxy_info_req(client_sock,header_buffer);
return;
}
if(extract_host(header_buffer) < 0)
{
return;
}
}
}
if ((remote_sock = create_connection()) < 0) {
return;
}
if (fork() == 0) { // 创建子进程用于从客户端转发数据到远端socket接口
if(strlen(header_buffer) > 0 && !is_http_tunnel)
{
forward_header(remote_sock); //普通的http请求先转发header
}
forward_data(client_sock, remote_sock);
exit(0);
}
if (fork() == 0) { // 创建子进程用于转发从远端socket接口过来的数据到客户端
if(io_flag == W_S_ENC)
{
io_flag = R_C_DEC; // 发送请求给服务端进行编码,读取服务端的响应则进行解码
} else if (io_flag == R_C_DEC)
{
io_flag = W_S_ENC; //接收客户端请求进行解码,那么响应客户端请求需要编码
}
if(is_http_tunnel)
{
send_tunnel_ok(client_sock);
}
forward_data(remote_sock, client_sock);
exit(0);
}
close(remote_sock);
close(client_sock);
}
void forward_data(int source_sock, int destination_sock) {
char buffer[BUF_SIZE];
int n;
while ((n = receive_data(source_sock, buffer, BUF_SIZE)) > 0)
{
send_data(destination_sock, buffer, n);
}
shutdown(destination_sock, SHUT_RDWR);
shutdown(source_sock, SHUT_RDWR);
}
void forward_header(int destination_sock)
{
rewrite_header();
int len = strlen(header_buffer);
send_data(destination_sock,header_buffer,len) ;
}
// 代理中的完整URL转发前需改成 path 的形式
void rewrite_header()
{
char * p = strstr(header_buffer,"http://");
char * p0 = strchr(p,'\0');
char * p5 = strstr(header_buffer,"HTTP/"); // "HTTP/" 是协议标识 如 "HTTP/1.1"
int len = strlen(header_buffer);
if(p)
{
char * p1 = strchr(p + 7,'/');
if(p1 && (p5 > p1))
{
// 转换url到 path
memcpy(p,p1,(int)(p0 -p1));
int l = len - (p1 - p) ;
header_buffer[l] = '\0';
} else
{
char * p2 = strchr(p,' '); // GET http://3g.sina.com.cn HTTP/1.1
memcpy(p + 1,p2,(int)(p0-p2));
*p = '/'; // url 没有路径使用根
int l = len - (p2 - p ) + 1;
header_buffer[l] = '\0';
}
}
}
int receive_data(int socket, char * buffer, int len)
{
int n = recv(socket, buffer, len, 0);
if(io_flag == R_C_DEC && n > 0)
{
int i;
for(i = 0; i< n; i++ )
{
buffer[i] ^= 1;
}
}
return n;
}
int send_data(int socket,char * buffer,int len)
{
if(io_flag == W_S_ENC)
{
int i;
for(i = 0; i < len ; i++)
{
buffer[i] ^= 1;
}
}
return send(socket,buffer,len,0);
}
int create_connection() {
struct sockaddr_in server_addr;
struct hostent *server;
int sock;
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
return -1;
}
if ((server = gethostbyname(remote_host)) == NULL) {
errno = EFAULT;
return -1;
}
memset(&server_addr, 0, sizeof(server_addr));
server_addr.sin_family = AF_INET;
memcpy(&server_addr.sin_addr.s_addr, server->h_addr, server->h_length);
server_addr.sin_port = htons(remote_port);
if (connect(sock, (struct sockaddr *) &server_addr, sizeof(server_addr)) < 0) {
return -1;
}
return sock;
}
int _main(int argc, char *argv[])
{
header_buffer = (char *) malloc(MAX_HEADER_SIZE);
int server_sock, optval;
struct sockaddr_in server_addr;
if ((server_sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
return -1;
}
if (setsockopt(server_sock, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval)) < 0) {
return -1;
}
memset(&server_addr, 0, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(PORT);
server_addr.sin_addr.s_addr = INADDR_ANY;
if (bind(server_sock, (struct sockaddr*)&server_addr, sizeof(server_addr)) != 0) {
return -1;
}
if (listen(server_sock, 17) < 0) {
return -1;
}
struct sockaddr_in clnt_addr;
socklen_t clnt_addr_size = sizeof(clnt_addr);
while (1) {
int client_socket =
accept(server_sock, (struct sockaddr *) &clnt_addr,
&clnt_addr_size);
if (fork() == 0) { // 创建子进程处理客户端连接请求
close(server_sock);
handle_client(client_socket, clnt_addr);
printf("%s", header_buffer);
exit(0);
}
close(client_socket);
}
}
int main(int argc, char *argv[])
{
return _main(argc,argv);
}