/***
This file is part of avahi.
avahi is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
avahi 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 Lesser General
Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with avahi; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA.
***/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <string.h>
#include <net/if.h>
#include <errno.h>
#include <string.h>
#include "avahi-common/avahi-malloc.h"
#include "log.h"
#include "iface.h"
#include "iface-linux.h"
#ifndef IFLA_RTA
#include <linux/if_addr.h>
#define IFLA_RTA(r) ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct ifinfomsg))))
#endif
#ifndef IFA_RTA
#include <linux/if_addr.h>
#define IFA_RTA(r) ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct ifaddrmsg))))
#endif
static int netlink_list_items(AvahiNetlink *nl, uint16_t type, unsigned *ret_seq) {
struct nlmsghdr *n;
struct rtgenmsg *gen;
uint8_t req[1024];
/* Issue a wild dump NETLINK request */
memset(&req, 0, sizeof(req));
n = (struct nlmsghdr*) req;
n->nlmsg_len = NLMSG_LENGTH(sizeof(struct rtgenmsg));
n->nlmsg_type = type;
n->nlmsg_flags = NLM_F_REQUEST|NLM_F_DUMP;
n->nlmsg_pid = 0;
gen = NLMSG_DATA(n);
memset(gen, 0, sizeof(struct rtgenmsg));
gen->rtgen_family = AF_UNSPEC;
return avahi_netlink_send(nl, n, ret_seq);
}
static void netlink_callback(AvahiNetlink *nl, struct nlmsghdr *n, void* userdata) {
AvahiInterfaceMonitor *m = userdata;
/* This routine is called for every RTNETLINK response packet */
assert(m);
assert(n);
assert(m->osdep.netlink == nl);
if (n->nlmsg_type == RTM_NEWLINK) {
/* A new interface appeared or an existing one has been modified */
struct ifinfomsg *ifinfomsg = NLMSG_DATA(n);
AvahiHwInterface *hw;
struct rtattr *a = NULL;
size_t l;
/* A (superfluous?) sanity check */
if (ifinfomsg->ifi_family != AF_UNSPEC)
return;
/* Check whether there already is an AvahiHwInterface object
* for this link, so that we can update its data. Note that
* Netlink sends us an RTM_NEWLINK not only when a new
* interface appears, but when it changes, too */
if (!(hw = avahi_interface_monitor_get_hw_interface(m, ifinfomsg->ifi_index)))
/* No object found, so let's create a new
* one. avahi_hw_interface_new() will call
* avahi_interface_new() internally twice for IPv4 and
* IPv6, so there is no need for us to do that
* ourselves */
if (!(hw = avahi_hw_interface_new(m, (AvahiIfIndex) ifinfomsg->ifi_index)))
return; /* OOM */
/* Check whether the flags of this interface are OK for us */
hw->flags_ok =
(ifinfomsg->ifi_flags & IFF_UP) &&
(!m->server->config.use_iff_running || (ifinfomsg->ifi_flags & IFF_RUNNING)) &&
!(ifinfomsg->ifi_flags & IFF_LOOPBACK) &&
(ifinfomsg->ifi_flags & IFF_MULTICAST) &&
(m->server->config.allow_point_to_point || !(ifinfomsg->ifi_flags & IFF_POINTOPOINT));
/* Handle interface attributes */
l = NLMSG_PAYLOAD(n, sizeof(struct ifinfomsg));
a = IFLA_RTA(ifinfomsg);
while (RTA_OK(a, l)) {
switch(a->rta_type) {
case IFLA_IFNAME:
/* Fill in interface name */
avahi_free(hw->name);
hw->name = avahi_strndup(RTA_DATA(a), RTA_PAYLOAD(a));
break;
case IFLA_MTU:
/* Fill in MTU */
assert(RTA_PAYLOAD(a) == sizeof(unsigned int));
hw->mtu = *((unsigned int*) RTA_DATA(a));
break;
case IFLA_ADDRESS:
/* Fill in hardware (MAC) address */
hw->mac_address_size = RTA_PAYLOAD(a);
if (hw->mac_address_size > AVAHI_MAC_ADDRESS_MAX)
hw->mac_address_size = AVAHI_MAC_ADDRESS_MAX;
memcpy(hw->mac_address, RTA_DATA(a), hw->mac_address_size);
break;
default:
;
}
a = RTA_NEXT(a, l);
}
/* Check whether this interface is now "relevant" for us. If
* it is Avahi will start to announce its records on this
* interface and send out queries for subscribed records on
* it */
avahi_hw_interface_check_relevant(hw);
/* Update any associated RRs of this interface. (i.e. the
* _workstation._tcp record containing the MAC address) */
avahi_hw_interface_update_rrs(hw, 0);
} else if (n->nlmsg_type == RTM_DELLINK) {
/* An interface has been removed */
struct ifinfomsg *ifinfomsg = NLMSG_DATA(n);
AvahiHwInterface *hw;
/* A (superfluous?) sanity check */
if (ifinfomsg->ifi_family != AF_UNSPEC)
return;
/* Get a reference to our AvahiHwInterface object of this interface */
if (!(hw = avahi_interface_monitor_get_hw_interface(m, (AvahiIfIndex) ifinfomsg->ifi_index)))
return;
/* Free our object */
avahi_hw_interface_free(hw, 0);
} else if (n->nlmsg_type == RTM_NEWADDR || n->nlmsg_type == RTM_DELADDR) {
/* An address has been added, modified or removed */
struct ifaddrmsg *ifaddrmsg = NLMSG_DATA(n);
AvahiInterface *i;
struct rtattr *a = NULL;
size_t l;
AvahiAddress raddr, rlocal, *r;
int raddr_valid = 0, rlocal_valid = 0;
/* We are only interested in IPv4 and IPv6 */
if (ifaddrmsg->ifa_family != AF_INET && ifaddrmsg->ifa_family != AF_INET6)
return;
/* Try to get a reference to our AvahiInterface object for the
* interface this address is assigned to. If ther is no object
* for this interface, we ignore this address. */
if (!(i = avahi_interface_monitor_get_interface(m, (AvahiIfIndex) ifaddrmsg->ifa_index, avahi_af_to_proto(ifaddrmsg->ifa_family))))
return;
/* Fill in address family for our new address */
rlocal.proto = raddr.proto = avahi_af_to_proto(ifaddrmsg->ifa_family);
l = NLMSG_PAYLOAD(n, sizeof(struct ifaddrmsg));
a = IFA_RTA(ifaddrmsg);
while (RTA_OK(a, l)) {
switch(a->rta_type) {
case IFA_ADDRESS:
if ((rlocal.proto == AVAHI_PROTO_INET6 && RTA_PAYLOAD(a) != 16) ||
(rlocal.proto == AVAHI_PROTO_INET && RTA_PAYLOAD(a) != 4))
return;
memcpy(rlocal.data.data, RTA_DATA(a), RTA_PAYLOAD(a));
rlocal_valid = 1;
break;
case IFA_LOCAL:
/* Fill in local address data. Usually this is
* preferable over IFA_ADDRESS if both are set,
* since this refers to the local address of a PPP
* link while IFA_ADDRESS refers to the other
* end. */
if ((raddr.proto == AVAHI_PROTO_INET6 && RTA_PAYLOAD(a) != 16) ||
(raddr.proto == AVAHI_PROTO_INET && RTA_PAYLOAD(a) != 4))
return;
memcpy(raddr.data.data, RTA_DATA(a), RTA_PAYLOAD(a));
raddr_valid = 1;
break;
default:
;
}
a = RTA_NEXT(a, l);
}
/* If there was no adress attached to this message, let's quit. */
if (rlocal_valid)
r = &rlocal;
else if (raddr_valid)
r = &raddr;
else
return;
if (n->nlmsg_type == RTM_NEWADDR) {
AvahiInterfaceAddress *addr;
/* This address is new or has been modified, so let's get an object for it */
if (!(addr = avahi_interface_monitor_get_address(m, i, r)))
/* Mmm, no object existing yet, so let's create a new one */
if (!(addr = avahi_interface_address_new(m, i, r, ifaddrmsg->ifa_prefixlen)))
return; /* OOM */
/* Update the scope field for the address */
addr->global_scope = ifaddrmsg->ifa_scope == RT_SCOPE_UNIVERSE || ifaddrmsg->ifa_scope == RT_SCOPE_SITE;
addr->deprecated = !!(ifaddrmsg->ifa_flags & IFA_F_DEPRECATED);
} else {
AvahiInterfaceAddress *addr;
assert(n->nlmsg_type == RTM_DELADDR);
/* Try to get a reference to our AvahiInterfaceAddress object for this address */
if (!(addr = avahi_interface_monitor_get_address(m, i, r)))
return;
/* And free it */
avahi_interface_address_free(addr);
}
/* Avahi only considers interfaces with at least one address
* attached relevant. Since we migh have added or removed an
* address, let's have it check again whether the interface is
* now relevant */
avahi_interface_check_relevant(i);
/* Update any associated RRs, like A or AAAA for our new/removed address */
avahi_interface_update_rrs(i, 0);
} else if (n->nlmsg_type == NLMSG_DONE) {
/* This wild dump request ended, so let's see what we do next */
if (m->osdep.list == LIST_IFACE) {
/* Mmmm, interfaces have been wild dumped already, so
* let's go on with wild dumping the addresses */
if (netlink_list_items(m->osdep.netlink, RTM_GETADDR, &m->osdep.query_addr_seq) < 0) {
avahi_log_warn("NETLINK: Failed to list addrs: %s", strerror(errno));
m->osdep.list = LIST_DONE;
} else
/* Update state information */
m->osdep.list = LIST_ADDR;
} else
/* We're done. Tell avahi_interface_monitor_sync() to finish. */
m->osdep.list = LIST_DONE;
if (m->osdep.list == LIST_DONE) {
/* Only after this boolean variable has been set, Avahi
* will start to announce or browse on all interfaces. It
* is originaly set to 0, which means that relevancy
* checks and RR updates are disabled during the wild
* dumps. */
m->list_complete = 1;
/* So let's check if any interfaces are relevant now */
avahi_interface_monitor_check_relevant(m);
/* And update all RRs attached to any interface */
avahi_interface_monitor_update_rrs(m, 0);
/* Tell the user that the wild dump is complete */
avahi_log_info("Network interface enumeration completed.");
}
} else if (n->nlmsg_type == NLMSG_ERROR &&
(n->nlmsg_seq == m->osdep.query_link_seq || n->nlmsg_seq == m->osdep.query_addr_seq)) {
struct nlmsgerr *e = NLMSG_DATA (n);
/* Some kind of error happened. Let's just tell the user and
* ignore it otherwise */
if (e->error)
avahi_log_warn("NETLINK: Failed to browse: %s", strerror(-e->error));
}
}
int avahi_interface_monitor_init_osdep(AvahiInterfaceMonitor *m) {
assert(m);
/* Initialize our own data */
m->osdep.netlink = NULL;
m->osdep.query_addr_seq = m->osdep.query_link_seq = 0;
/* Create a netlink object for us. It abstracts some things and
* makes netlink easier to use. It will attach to the main loop
* for us and call netlink_callback() whenever an event
* happens. */
if (!(m->osdep.netlink = avahi_netlink_new(m->server->poll_api, RTMGRP_LINK|RTMGRP_IPV4_IFADDR|RTMGRP_IPV6_IFADDR, netlink_callback, m)))
goto fail;
/* Set the initial state. */
m->osdep.list = LIST_IFACE;
/* Start the wild dump for the interfaces */
if (netlink_list_items(m->osdep.netlink, RTM_GETLINK, &m->osdep.query_link_seq) < 0)
goto fail;
return 0;
fail:
if (m->osdep.netlink) {
avahi_netlink_free(m->osdep.netlink);
m->osdep.netlink = NULL;
}
return -1;
}
void avahi_interface_monitor_free_osdep(AvahiInterfaceMonitor *m) {
assert(m);
if (m->osdep.netlink) {
avahi_netlink_free(m->osdep.netlink);
m->osdep.netlink = NULL;
}
}
void avahi_interface_monitor_sync(AvahiInterfaceMonitor *m) {
assert(m);
/* Let's handle netlink events until we are done with wild
* dumping */
while (!m->list_complete)
if (!avahi_netlink_work(m->osdep.netlink, 1) == 0)
break;
/* At this point Avahi knows about all local interfaces and
* addresses in existance. */
}