Sockets 在环回设备上打开的packetsocket两次接收所有数据包。如何过滤这些重复条目?
当我在环回接口(lo)上打开一个Sockets 在环回设备上打开的packetsocket两次接收所有数据包。如何过滤这些重复条目?,sockets,tcpdump,Sockets,Tcpdump,当我在环回接口(lo)上打开一个packetsocket并监听时,所有数据包都会被看到两次。为什么会这样 但是,使用tcpdump在接口上进行捕获会正确地忽略重复的条目。请参阅“筛选器接收的数据包”(其中包含重复数据包)和“捕获的数据包”。这个过滤是如何完成的 tcpdump-i低-s 0 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on lo, link-type EN
packetsocket
并监听时,所有数据包都会被看到两次。为什么会这样
但是,使用tcpdump在接口上进行捕获会正确地忽略重复的条目。请参阅“筛选器接收的数据包”(其中包含重复数据包)和“捕获的数据包”。这个过滤是如何完成的
tcpdump-i低-s 0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on lo, link-type EN10MB (Ethernet), capture size 65535 bytes
11:00:08.439542 IP 12.0.0.3 > localhost.localdomain: icmp 64: echo request seq 1
11:00:08.439559 IP localhost.localdomain > 12.0.0.3: icmp 64: echo reply seq 1
11:00:09.439866 IP 12.0.0.3 > localhost.localdomain: icmp 64: echo request seq 2
11:00:09.439884 IP localhost.localdomain > 12.0.0.3: icmp 64: echo reply seq 2
11:00:10.439389 IP 12.0.0.3 > localhost.localdomain: icmp 64: echo request seq 3
11:00:10.439410 IP localhost.localdomain > 12.0.0.3: icmp 64: echo reply seq 3
6 packets captured
12 packets received by filter
0 packets dropped by kernel
我的代码:
int main()
{
int sockFd;
if ( (sockFd=socket(PF_PACKET, SOCK_DGRAM, 0))<0 ) {
perror("socket()");
return -1;
}
/* bind the packet socket */
struct sockaddr_ll addr;
struct ifreq ifr;
strncpy (ifr.ifr_name, "lo", sizeof(ifr.ifr_name));
if(ioctl(sockFd, SIOCGIFINDEX, &ifr) == -1)
{
perror("iotcl");
return -1;
}
memset(&addr, 0, sizeof(addr));
addr.sll_family=AF_PACKET;
addr.sll_protocol=htons(ETH_P_ALL);
addr.sll_ifindex=ifr.ifr_ifindex;
if ( bind(sockFd, (struct sockaddr *)&addr, sizeof(addr)) ) {
perror("bind()");
return -1;
}
char buffer[MAX_BUFFER+1];
int tmpVal = 1;
while(tmpVal > 0)
{
tmpVal = recv (sockFd, buffer, MAX_BUFFER, 0);
cout<<"Received Pkt with Bytes "<<tmpVal <<endl;
}
}
intmain()
{
int-sockFd;
if((sockFd=socket(PF_数据包,SOCK_DGRAM,0))0)
{
tmpVal=recv(sockFd,缓冲区,最大缓冲区,0);
我没办法解决这个问题
从libcaps代码:
* - The loopback device gives every packet twice; on 2.2[.x] kernels,
* if we use PF_PACKET, we can filter out the transmitted version
* of the packet by using data in the "sockaddr_ll" returned by
* "recvfrom()", but, on 2.0[.x] kernels, we have to use
* PF_INET/SOCK_PACKET, which means "recvfrom()" supplies a
* "sockaddr_pkt" which doesn't give us enough information to let
* us do that.
侦听实体需要使用从recvfrom api获取的if_索引过滤重复数据包