A.I do so.
B.Me, too.
C.So I do.
D.Me, either.
第1题:
下面是一个简单的使用RAWSOCKET实现的ping程序,填入(n)处。
/*simple ping program*/
struct sockaddr_in saddr;
int rawsock;
unsigned short in_cksum(unsigned short*addr, int len)
{ int sum=0;
unsigned short res=0;
while(1en>1){
sum+=*addr++; len-=2;
}
if(len=1){
*((unsigned char *)(&res))=*((unsigned char *)addr); sum+=res;
}
sum=(sum>>16)+(sam & 0xffff);
sum+=(sum>>16); res=~sum;
return res;
}
void ping(int signo)
{
int len;
int i;
static unsigned short seq=0;
char buff[8192];
struct timeval tv;
struet icmp*icmph=(struct icmp * )buff;
long*data=(long*)icmph→icmp_data;
bzero(buff, 8192);
gettimeofday(&tv, NULL);
icmph→icmp_type=ICMP_ECHO;
icmph→icmp_code=0;
icmph→icmp_cksum=0;
icmph→icmp_id=0;
icmph→icmp_seq=0;
icmph→icmp_id=getpid()&0xffff;
icmph→icmp_seq=seq++;
data[0]=tv.tv_sec;
data[1]=tv.tv_usec;
for(i=8; i< ; i++)
icmph→icmp_data[i]=(unsigned char)i;
icmph→icmp_cksum=in_cksum((unsigned short *)buff, ? 72);
len; sendto(rawsock, buff, 72, 0, &saddr, sizeof(saddr));
alarm(1);
}
void sigint(int signo)
{ printf("CATCH SIGINT !!! \n");
close(rawsock);
exit(0);
}
void dumppkt(char*buf, int len)
{ struct ip*iph=(struct ip*)buf;
int i=iph→ip_h1*4;
struct icmp*icmph=(struct icmp*)&buf[i];
long*data=(long*)iemph→icmp_data;
struct timeval tv;
gettimeofday(&tv, NULL);
if(icmph→icmp_type! =ICMP_ECHOREPLY)
return;
if(icmph→icmp_id! =(getpid()&0xffff))
return;
printf("From %s:ttl=% d seq=% d time=%.2f ms\n",
inet_ntoa(iph→ip_src),iph→ip_ttl?,
icmph→icmp_seq,
(tv.tv_see-data[0])*1000.0+(tv.tv_usec-data[0])/1000.0);
}
int main(int argc, char*argv[])
{ int len;
stuct timeval now;
char recvbuff[8192];
if(1){
printf("%s aaa.bbb.ccc.ddd\n", argv[0]);
exit(1);
}
rawsock=soeket(AF_INET, (2), IPPROTO_ICMP);
if(rawsock<0) {
perror("soeket");
exit(1);
}
bzero ( &saddr, sizeof(saddr));
saddr.sin_family=(3);
if( inet_aton( argv[1], &saddr.sin_addr) <0) {
printf("invalid IP address: %s\n", argv[1]);
exit(1);
}
signal(SICALRM, ping);
signal(SICINT, sigint);
alarm(1);
while (1){
len=read (4), recvbuff, 8192);
if( len<0 && errno=EINTR)
continue;
else it( len<0)
perror("read");
else if( len>0)
dumppkt(recvbuff, len);
}
close (5);
exit(0);
}
第2题:
A.reading ...to watch
B.to read ...watching
C.to read ...watch
D.reading ...watching
第3题:
A.corn
B.gossip
C.maid
D.very
第4题:
已知某负载的电压u=-100sin314tV,电流i=10cos314tA,则该负载呈()(感、容或阻)性。
第5题:
I like sitting in the cafes,()the newspapers and()people .
Aread;watch
Breading;watching
Cread;watching
第6题:
12.
A.visiting
B.looking for
C. finding
D. watching
第7题:
The more the young students worked, the ________ energetic they became.
A: much
B: more
C: most
D: very
第8题:
A. to watch
B. watch
C. watched
D. watching
第9题:
2. 我没听见你刚才说的什么,我看电视呢。 I didn't hear what you said just now. I ________ (watch)TV.
第10题:
请选出下列单词中划线部分发音是/I/的单词选项。
A.led
B.kite
C.rid
D.like