How to get packet IP?

[leetow2003]

I see when I create the socket:
socket(PF_PACKET,SOCK_RAW,htons(ETH_P_ALL));
and I set the netcard to PROMISC,I can receive
all packet including ether,but I want to
receive packet IP,including ICMP,UDP,TCP,not ether,
how to create the socket?and how to set it up?

[Yarin]

I don't quite understand what your asking.
Are you asking how to create a socket that'll receive IMCP, UDP, and TCP communications together, without having to deal with raw sockets?
If so: It doesn't work that way. You'll have to create a socket for each protocol you want to handle, but bind them all to the same port & address, then multiplex them.
Or are you just asking how to get the IP of the peer you're communicating with?
If that, then: See the man page for recvfrom(), it's pretty straight forward from there.

[leetow2003]

Yes,I wand to know how to create a socket that'll receive IMCP, UDP, and TCP communications together,you said I must create a socket for each protocol ,
I see I go to try.Thank you

[leetow2003]

Hello,Yarin:
I create a socket:
socket(AF_INET,SOCK_RAW,IPPROTO_ICMP|IPPROTO_UDP|I PPROTO_TCP);
but when I recieve I find I can't some packet;
so I create three socket:
sk1=socket(AF_INET,SOCK_RAW,IPPROTO_ICMP);
sk2=socket(AF_INET,SOCK_RAW,IPPROTO_UDP);
sk3=socket(AF_INET,SOCK_RAW,IPPROTO_TCP);
and bind them all to the same port & address,but I don't how to multiplex them?
Could you tell me?Thank you very much.

[MK27]

I don't how to multiplex them?
Could you tell me?Thank you very much.

select()

Waiting for I/O - The GNU C Library

Nb. that current linux/POSIX systems require:

#include <sys/select.h>

with select(), which is not mentioned in that documentation.

[leetow2003]

I create a socket:
socket(AF_INET,SOCK_RAW,IPPROTO_ICMP);
I want to know how to set this socket to promisc?

[Yarin]

I create a socket:
socket(AF_INET,SOCK_RAW,IPPROTO_ICMP);
I want to know how to set this socket to promisc?

All right, your asking this again got me curious... I'm afraid I fed you some misinformation.
You _can_, in fact, get the raw data for all protocols (promiscuous mode). A la:

int fd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));

More information on this.

On multiplexing: As MK27 as pointed out, select() is one way of doing it, poll() is another. Both are widely supported (though select() is older). Unless performance is a considerable issue for you, which one to use is pretty much about preference.