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/* etherinfo.c - Retrieve ethernet interface info via NETLINK
*
* Copyright (C) 2009-2013 Red Hat Inc.
*
* David Sommerseth <davids@redhat.com>
* Parts of this code is based on ideas and solutions in iproute2
*
* This application is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; version 2.
*
* This application is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <Python.h>
#include <bits/sockaddr.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <stdlib.h>
#include <asm/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netlink/cache.h>
#include <netlink/addr.h>
#include <netlink/route/addr.h>
#include <netlink/route/link.h>
#include <netlink/route/rtnl.h>
#include <assert.h>
#include <errno.h>
#include <pthread.h>
#include "etherinfo_struct.h"
#include "etherinfo.h"
/*
*
* Internal functions for working with struct etherinfo
*
*/
/**
* Simple macro which makes sure the destination string is freed if used earlier.
*
* @param dst Destination pointer
* @param src Source pointer
*
*/
#define SET_STR_VALUE(dst, src) { \
if( dst ) { \
free(dst); \
}; \
dst = strdup(src); \
}
/**
* Frees the memory used by struct etherinfo
*
* @param ptr Pointer to a struct etherninfo element
*/
void free_etherinfo(struct etherinfo *ptr)
{
if( ptr == NULL ) { // Just for safety
return;
}
free(ptr->device);
if( ptr->hwaddress ) {
free(ptr->hwaddress);
}
Py_XDECREF(ptr->ipv4_addresses);
Py_XDECREF(ptr->ipv6_addresses);
free(ptr);
}
/**
* libnl callback function. Does the real parsing of a record returned by NETLINK. This function
* parses LINK related packets
*
* @param obj Pointer to a struct nl_object response
* @param arg Pointer to a struct etherinfo element where the parse result will be saved
*/
static void callback_nl_link(struct nl_object *obj, void *arg)
{
struct etherinfo *ethi = (struct etherinfo *) arg;
struct rtnl_link *link = (struct rtnl_link *) obj;
char hwaddr[130];
if( (ethi == NULL) || (ethi->hwaddress != NULL) ) {
return;
}
memset(&hwaddr, 0, 130);
nl_addr2str(rtnl_link_get_addr(link), hwaddr, sizeof(hwaddr));
SET_STR_VALUE(ethi->hwaddress, hwaddr);
}
/**
* libnl callback function. Does the real parsing of a record returned by NETLINK. This function
* parses ADDRESS related packets
*
* @param obj Pointer to a struct nl_object response
* @param arg Pointer to a struct etherinfo element where the parse result will be saved
*/
static void callback_nl_address(struct nl_object *obj, void *arg)
{
struct etherinfo *ethi = (struct etherinfo *) arg;
struct rtnl_addr *rtaddr = (struct rtnl_addr *) obj;
PyObject *addr_obj = NULL;
int af_family = -1;
if( ethi == NULL ) {
return;
}
assert(ethi->ipv4_addresses);
assert(ethi->ipv6_addresses);
/* Ensure that we're processing only known address types.
* Currently only IPv4 and IPv6 is handled
*/
af_family = rtnl_addr_get_family(rtaddr);
if( af_family != AF_INET && af_family != AF_INET6 ) {
return;
}
/* Prepare a new Python object with the IP address */
addr_obj = make_python_address_from_rtnl_addr(rtaddr);
if (!addr_obj) {
return;
}
/* Append the IP address object to the proper address list */
PyList_Append((af_family == AF_INET6 ? ethi->ipv6_addresses : ethi->ipv4_addresses),
addr_obj);
Py_DECREF(addr_obj);
}
/*
*
* Exported functions - API frontend
*
*/
/**
* Query NETLINK for ethernet configuration
*
* @param ethinf Pointer to an available struct etherinfo element. The 'device' member
* must contain a valid string to the device to query for information
* @param nlc Pointer to the libnl handle, which is used for the query against NETLINK
* @param query What to query for. Must be NLQRY_LINK or NLQRY_ADDR.
*
* @return Returns 1 on success, otherwise 0.
*/
int get_etherinfo(struct etherinfo_obj_data *data, nlQuery query)
{
struct nl_cache *link_cache;
struct nl_cache *addr_cache;
struct rtnl_addr *addr;
struct rtnl_link *link;
struct etherinfo *ethinf = NULL;
int ret = 0;
if( !data || !data->ethinfo ) {
return 0;
}
ethinf = data->ethinfo;
/* Open a NETLINK connection on-the-fly */
if( !open_netlink(data) ) {
PyErr_Format(PyExc_RuntimeError,
"Could not open a NETLINK connection for %s",
ethinf->device);
return 0;
}
/* Find the interface index we're looking up.
* As we don't expect it to change, we're reusing a "cached"
* interface index if we have that
*/
if( ethinf->index < 0 ) {
if( rtnl_link_alloc_cache(*data->nlc, AF_UNSPEC, &link_cache) < 0) {
return 0;
}
link = rtnl_link_get_by_name(link_cache, ethinf->device);
if( !link ) {
return 0;
}
ethinf->index = rtnl_link_get_ifindex(link);
if( ethinf->index < 0 ) {
return 0;
}
rtnl_link_put(link);
nl_cache_free(link_cache);
}
/* Query the for requested info vai NETLINK */
switch( query ) {
case NLQRY_LINK:
/* Extract MAC/hardware address of the interface */
if( rtnl_link_alloc_cache(*data->nlc, AF_UNSPEC, &link_cache) < 0) {
return 0;
}
link = rtnl_link_alloc();
rtnl_link_set_ifindex(link, ethinf->index);
nl_cache_foreach_filter(link_cache, OBJ_CAST(link), callback_nl_link, ethinf);
rtnl_link_put(link);
nl_cache_free(link_cache);
ret = 1;
break;
case NLQRY_ADDR:
/* Extract IP address information */
if( rtnl_addr_alloc_cache(*data->nlc, &addr_cache) < 0) {
return 0;
}
addr = rtnl_addr_alloc();
rtnl_addr_set_ifindex(addr, ethinf->index);
/* Make sure we don't have any old IPv4 addresses saved */
Py_XDECREF(ethinf->ipv4_addresses);
ethinf->ipv4_addresses = PyList_New(0);
if (!ethinf->ipv4_addresses) {
return 0;
}
/* Likewise for IPv6 addresses: */
Py_XDECREF(ethinf->ipv6_addresses);
ethinf->ipv6_addresses = PyList_New(0);
if (!ethinf->ipv6_addresses) {
return 0;
}
/* Retrieve all address information */
nl_cache_foreach_filter(addr_cache, OBJ_CAST(addr), callback_nl_address, ethinf);
rtnl_addr_put(addr);
nl_cache_free(addr_cache);
ret = 1;
break;
default:
ret = 0;
}
return ret;
}
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