我想使用原始套接字使用发送器和接收器程序发送字符数组。我能够在接收端获得正确的字节数,但打印出的值是垃圾。有人可以帮我在这里吗?原始套接字:接收器打印垃圾值
发射机:
int create_raw_socket(char *dev)
{
struct sockaddr_ll sll;
struct ifreq ifr;
int fd, ifi, rb;
bzero(&sll, sizeof(sll));
bzero(&ifr, sizeof(ifr));
fd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
assert(fd != -1);
strncpy((char *)ifr.ifr_name, dev, IFNAMSIZ);
ifi = ioctl(fd, SIOCGIFINDEX, &ifr);
assert(ifi != -1);
sll.sll_protocol = htons(ETH_P_ALL);
sll.sll_family = AF_PACKET;
sll.sll_ifindex = ifr.ifr_ifindex;
rb = bind(fd, (struct sockaddr *)&sll,sizeof(sll));
assert(rb != -1);
return fd;
}
int SendPacket(char *dev ,unsigned char *send_packet, int packet_len)
{
int num_sent= 0;
int sockaddress = create_raw_socket(dev);
if((num_sent = write(sockaddress, &send_packet, packet_len)) != packet_len)
{
close(sockaddress);
return 0;
}
else
{
close(sockaddress);
return 1;
}
}
int main(int argc, char**argv)
{
int x,fd,s;
char *send_packet="HELLO";
int len = sizeof(send_packet);
while(1)
{
if(!SendPacket((argv[1]), send_packet, len))
perror("Error sending packet");
else
printf("Packet sent successfully with payload : %s\n" ,send_packet);
}
return 0;
}
接收机:
int main(int argc, char **argv)
{
struct sockaddr addr;
int sock_fd, fromlen,s;
char buf[PACKET_LENGTH];
char *dev = argv[1];
while(1)
{
fromlen=sizeof(addr);
sock_fd = create_raw_socket(dev); /* Creating the raw socket */
int x= recvfrom(sock_fd,&buf,sizeof(buf),0,&addr,&fromlen);
printf("\n Number of bytes of data received is %d \n",x);
printf("\nPayload Received from client... is %s \n", buf);
close(sock_fd);
}
return 0;
}
这对'write'调用是正确的,因为'send_packet'是一个指针,但对'recvfrom'的调用没有什么区别,因为'buf'是一个数组。数组类型具有这样的属性,即它们的地址在数值上等同于它们的第一个元素的地址,所以对于数组'x',总是这样:'(void *)&x ==(void *)&x [0]'。 –
谢谢@Attila和亚当,它像一个魅力:) – hektor