Партнёры:
Хостинг:
packet, PF_PACKET - packet interface on device level.
#include <sys/socket.h>
#include <sys/if_packet.h> packet_socket = socket(PF_PACKET, socket_type, protocol);
socket_type
is either
SOCK_RAW
for raw packets including the link level header or
SOCK_DGRAM
for cooked packets with the link level header removed. The link level
header informations are available in a common format in a
sockaddr_ll.
protocol
is the IEEE 802.3 protocol number in network order. See the
<sys/if_ether.h>
include file for a list of allowed protocols.
All incoming packets with
that protocol will be first passed to the packet socket, after that to
the other protocols implemented in the kernel.
Only processes with effective uid 0 or the CAP_NET_RAW attribute set may open
packet sockets.
There are two types of packet sockets: SOCK_RAW and SOCK_DGRAM. SOCK_RAW is directly passed to and from the device driver without any changes in the packet data. The user program has to know about the physical header structure of the device to properly set up and parse the packet. The address is still parsed and passed in a standard sockaddr_ll address structure. SOCK_RAW is similar but not compatible to the obsolete SOCK_PACKET of Linux 2.0.
SOCK_DGRAM operates on a slightly higher level. The physical header is removed before passing the packet to the user (and prepended before sending it).
Per default all packets with the specified protocol received from any interface are passed to a packet socket. To only get packets from a specific interface use bind(2) with a sockaddr_ll address to bind the packet to an interface.
For sending to SOCK_RAW sockets the user supplied buffer has to contain the complete packet including the physical layer header. That packet is then queued unmodified to the network driver of the interface defined by the destination address. Packets sent through a SOCK_DGRAM packet socket get a suitable physical layer header based on the information in the sockaddr_ll destination address before they are queued.
struct sockaddr_ll
{
unsigned short sll_family; /* Always AF_PACKET */
unsigned short sll_protocol;/* Physical layer protocol in network order */
int sll_ifindex;/* Interface number */
unsigned short sll_hatype; /* Header type */
unsigned char sll_pkttype;/* Packet type */
unsigned char sll_halen; /* Length of address */
unsigned char sll_addr[8];/* Physical layer address */
};
sll_protocol is standard ethernet protocol type in network order as defined in the sys/if_ether.h include file. sll_hatype is a ARP type as defined in the sys/if_arp.h include file. sll_pkttype contains the packet type. Valid types are PACKET_HOST for a packet addressed to the local host, PACKET_BROADCAST for a physical layer broadcasted packet, PACKET_MULTICAST for a packet sent to a physical layer multicast address, PACKET_OTHERHOST for a packet to some other host that has been caught by a device driver in promiscuous mode, and PACKET_OUTGOING for a packet originated from the local host that is looped back to a packet socket. sll_halen and sll_addr contain the physical layer (e.g. IEEE 802.3) address and its length.
struct packet_mreq
{
intmr_ifindex; /* interface index */
unsigned shortmr_type; /* mreq type as defined below */
unsigned shortmr_alen; /* address length */
unsigned charmr_address[8]; /* physical layer address */
};
mr_interface contains the interface index for the interface whose status should be changed. Valid options for mr_type are PACKET_MR_MULTICAST to bind the socket to the physical layer multicast group specified in mr_address and mr_alen, PACKET_MR_PROMISC to enable promiscuous mode on the interface to receive all packets on a shared medium, PACKET_MR_ALLMULTI sets the socket up to receive all multicast packets arriving at the interface. PACKET_DROP_MEMBERSHIP removes the binding or setting.
SIOCGSTAMP Return a struct timeval with the receive timestamp of the last packet passed to the user. This is useful for accurate round trip time measurements and the like. See setitimer(2) for a description of struct timeval.
FIOCSETOWN and SIOCSPGRP set the process or process group (negative value) to send SIGIO to when an asynchronous IO operation has finished. Argument is a pid_t.
FIOCGETOWN and SIOCGPGRP get the current process or process group that receive SIGIOs, or 0 when none is set. Argument is a pid_t.
In addition you may pass all network device ioctls.
struct sockaddr_pkt
{
unsigned short spkt_family;
unsigned char spkt_device[14];
unsigned short spkt_protocol;
};
spkt_family contains the device type, spkt_protocol is the IEEE 802.3 protocol type as defined in the sys/if_ether.h include. spkt_device is the device name as a null terminated string, e.g. eth0.
This structure is obsolete and should not be used in new code.
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