net.c

/* Copyright (c) 2006-2012, DNSPod Inc.
 * All rights reserved.

 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met: 
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer. 
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 * The views and conclusions contained in the software and documentation are those
 * of the authors and should not be interpreted as representing official policies, 
 * either expressed or implied, of the FreeBSD Project.
 */


#include "net.h"


//reserved ip
//10.0.0.0:8
//172.16.0.0:12
//192.168.0.0:16
//0.0.0.0
//255.255.255.255
//127.0.0.0:8
//224.0.0.0:18
int check_client_addr(struct sockaddr_in *addr)
{
 return 0;
}


//add fd to backdoor
//only 1 udp fd at first
int add_backdoor(int fd)
{
 int epfd,ret;
 struct epoll_event ev;
 epfd = epoll_create(BACK_EVENT);
 if(epfd < 0)
	dns_error(0,"epoll bd");
 ev.data.fd = fd;
 ev.events = EPOLLIN; //with out EPOLLET
 ret = epoll_ctl(epfd,EPOLL_CTL_ADD,ev.data.fd,&ev);
 if(ret < 0)
	dns_error(0,"epoll add udp backdoor");
 return epfd;
}


int set_recv_timeout(int fd,int sec,int usec)
{
 int ret;
 struct timeval tv;
 tv.tv_sec = sec;
 tv.tv_usec = usec;
 ret = setsockopt(fd,SOL_SOCKET,SO_RCVTIMEO,(char*)&tv,sizeof(struct timeval));
 return ret;
}


int create_socket(int port,int proto,uchar *addr)
{
 int fd = -1,pt = -1;
 struct sockaddr_in srv;
 if(proto == UDP)
	pt = SOCK_DGRAM;
 else if(proto == TCP)
	pt = SOCK_STREAM;
 fd = socket(AF_INET,pt,0);
 if(fd <= 0)
	 return -1;
 srv.sin_family = AF_INET;
 if(addr == NULL)
	srv.sin_addr.s_addr = htonl(INADDR_ANY);
 else
	inet_aton(addr,&srv.sin_addr);
 srv.sin_port = htons(port);
 if(bind(fd,(SA*)&srv,sizeof(srv)) < 0)
	{
	 perror("bind:");
	 return -1;
	}
 if(proto == SOCK_STREAM)
	 listen(fd,512);
 return fd;
}


int connect_to(struct sockinfo *si)
{
 int ret = 0;
 //printf("CONN!!!\n");
 socklen_t len = sizeof(struct sockaddr_in);
 ret = connect(si->fd,(SA*)&si->addr,len);
 if(ret < 0)
	{
	 if(errno == EINPROGRESS)
		return 0;
	 printf("%d,%d,",si->fd,errno);
	 perror("conn");
	 return -1;
	}
 return 0;
}


int tcp_write_info(struct sockinfo *ri,int vi) //for dns only
{
 int i,ret;
 ret = send(ri->fd,ri->buf,ri->buflen,MSG_NOSIGNAL);
 if(ret < 0)
	{
	 printf("%d,",errno);
	 perror("tcp send");
	}
 if(vi == 1)
	{
	 printf("fd is %d\n",ri->fd);
	 for(i = 0;i < ri->buflen;i ++)
		printf("%x,",ri->buf[i]);
	 printf("\n");
	}
 return ret;
}


int udp_write_info(struct sockinfo *ri,int vi)
{
 int i,ret;
 socklen_t len;
 if(vi)
 	{
	 dbg_print_addr((struct sockaddr_in*)&(ri->addr));
 	 for(i = 0;i < ri->buflen;i ++)
		printf("%x,",ri->buf[i]);
	 printf("\n");
 	}
 len = sizeof(struct sockaddr_in);
 ((struct sockaddr_in*)&(ri->addr))->sin_family = AF_INET;
 ret = sendto(ri->fd,ri->buf,ri->buflen,0,(SA*)&(ri->addr),len);
 if(ret < 0)
	{
	 perror("write udp");
	 printf("len %u,fd %d\n",len,ri->fd);
	 dbg_print_addr((struct sockaddr_in*)&(ri->addr));
 	 for(i = 0;i < ri->buflen;i ++)
		printf("%x,",ri->buf[i]);
	 printf("\n");
	}
 return ret;
}


int tcp_read_dns_msg(struct sockinfo *si,uint max,int vi) //for dns only.
{
 int ret = 0,i,tp,rcvnum;
 int len;
 uchar buf[4] = {0};
 ushort le = 0;
 tp = recv(si->fd,buf,2,0);
 if(tp < 0)
	{
	 printf("%d,", si->fd);
	 perror("tp");
	 return -1;
	}
 if(tp == 0) //peer closed
	return 0;
 le = *(ushort*)buf;
 le = ntohs(le);
 if(le > max)
	{
	 printf("too large %d,%u,%d\n",si->fd,le,max);
	 return -1;
	}
 while(ret < le) //should set time out here
	{
	 rcvnum = recv(si->fd,si->buf + ret,si->buflen - ret,0);
	 if(rcvnum < 0)
		{
		 if(errno == EAGAIN || errno == EWOULDBLOCK)
			continue;
	 	 printf("tcp data %d,%d,%d",si->fd,le,ret);
		 perror("tcp read");
		 return -1;
		}
	 if(rcvnum == 0)
		{
		 ret = -1;
		 break;
		}
	 ret += rcvnum;
	}
 return ret;
}


int udp_read_msg(struct sockinfo *si,int visible)
{
 int ret,i;
 socklen_t len = sizeof(struct sockaddr_in);
 ret = recvfrom(si->fd,si->buf,si->buflen,0,(SA*)&(si->addr),&len);
 if(ret < 0)
	{
	 //perror("read udp");
	 return ret;
	}
 //printf("%d,",ret);
 //dbg_print_addr(&si->addr);
 if(visible)
 {
 for(i = 0;i < ret;i ++)
	printf("%x,",si->buf[i]);
 printf("\n");
 }
 return ret;
}


int set_sock_buff(int fd,int m)
{
 int ret;
 int bufsize = m * 1024 * 1024; //1m
 if(fd <= 0)
	return -1;
 ret = setsockopt(fd,SOL_SOCKET,SO_RCVBUF,
	(const uchar*)&bufsize,sizeof(int));
 return ret;
}


int set_non_block(int fd)
{
 int opt = fcntl(fd,F_GETFL,0);
 if(opt < 0)
	return -1;
 opt |= O_NONBLOCK;
 return (fcntl(fd,F_SETFL,opt));
}


int make_bin_from_str(uchar *bin,const uchar *str)
{
 int i,n;
 uchar val = 0;
 for(i = 0;i < 4;i ++)
	{
	 while((str[0] != '.') && (str[0] != 0))
		{
		 val = val * 10 + str[0] - '0';
		 str ++;
		}
	 str ++; //jump '.'
	 bin[0] = val;
	 val = 0;
	 bin ++; //next digit
	}
 return 0;
}


int make_addr_from_bin(struct sockaddr_in *addr,uchar *data)
{
 uchar ipv4[16] = {0};
 int idx = 0;
 int i;
 ushort val = 0;
 if(data[0] == 0 && data[1] == 0 && data[2] == 0 && data[3] == 0)
	return -1;
 for(i = 0;i < 4;i ++)
	{
	 val = (ushort)data[i];
	 if(val > 99)
		{
		 ipv4[idx] = val / 100 + '0';
		 idx ++;
		}
	 if(val > 9)
		{
		 ipv4[idx] = (val % 100) / 10 + '0';
		 idx ++;
		}
	 ipv4[idx] = val % 10 + '0';
	 idx ++;
	 ipv4[idx] = '.';
	 idx ++;
	}
 ipv4[idx - 1] = 0;
 i = inet_aton(ipv4,&addr->sin_addr);
 return 0;
}


//---------------------debug-------------------------------
int dbg_print_addr(struct sockaddr_in *addr)
{
 int port;
 uchar str[16],*ret;
 uint i;
 if(addr == NULL)
	{
	 printf("null addr\n");
	 return 0;
	}
 i = addr->sin_addr.s_addr;
 printf("%u.%u.%u.%u\n",i % (256),i / 256 % 256,i / 256 / 256 % 256,i / 256 / 256 / 256);
 return 0;
}