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* genetlink: Optimize and one bug fix in genl_generate_id()Krishna Kumar2009-10-18
| | | | | | | | | | | | | | | | | | | 1. GENL_MIN_ID is a valid id -> no need to start at GENL_MIN_ID + 1. 2. Avoid going through the ids two times: If we start at GENL_MIN_ID+1 (*or bigger*) and all ids are over!, the code iterates through the list twice (*or lesser*). 3. Simplify code - no need to start at idx=0 which gets reset to GENL_MIN_ID. Patch on net-next-2.6. Reboot test shows that first id passed to genl_register_family was 16, next two were GENL_ID_GENERATE and genl_generate_id returned 17 & 18 (user level testing of same code shows expected values across entire range of MIN/MAX). Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* genetlink: Optimize genl_register_family()Krishna Kumar2009-10-18
| | | | | | | | | | genl_register_family() doesn't need to call genl_family_find_byid when GENL_ID_GENERATE is passed during register. Patch on net-next-2.6, compile and reboot testing only. Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* genetlink: fix netns vs. netlink table locking (2)Johannes Berg2009-09-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | Similar to commit d136f1bd366fdb7e747ca7e0218171e7a00a98a5, there's a bug when unregistering a generic netlink family, which is caught by the might_sleep() added in that commit: BUG: sleeping function called from invalid context at net/netlink/af_netlink.c:183 in_atomic(): 1, irqs_disabled(): 0, pid: 1510, name: rmmod 2 locks held by rmmod/1510: #0: (genl_mutex){+.+.+.}, at: [<ffffffff8138283b>] genl_unregister_family+0x2b/0x130 #1: (rcu_read_lock){.+.+..}, at: [<ffffffff8138270c>] __genl_unregister_mc_group+0x1c/0x120 Pid: 1510, comm: rmmod Not tainted 2.6.31-wl #444 Call Trace: [<ffffffff81044ff9>] __might_sleep+0x119/0x150 [<ffffffff81380501>] netlink_table_grab+0x21/0x100 [<ffffffff813813a3>] netlink_clear_multicast_users+0x23/0x60 [<ffffffff81382761>] __genl_unregister_mc_group+0x71/0x120 [<ffffffff81382866>] genl_unregister_family+0x56/0x130 [<ffffffffa0007d85>] nl80211_exit+0x15/0x20 [cfg80211] [<ffffffffa000005a>] cfg80211_exit+0x1a/0x40 [cfg80211] Fix in the same way by grabbing the netlink table lock before doing rcu_read_lock(). Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* genetlink: fix netns vs. netlink table lockingJohannes Berg2009-09-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | Since my commits introducing netns awareness into genetlink we can get this problem: BUG: scheduling while atomic: modprobe/1178/0x00000002 2 locks held by modprobe/1178: #0: (genl_mutex){+.+.+.}, at: [<ffffffff8135ee1a>] genl_register_mc_grou #1: (rcu_read_lock){.+.+..}, at: [<ffffffff8135eeb5>] genl_register_mc_g Pid: 1178, comm: modprobe Not tainted 2.6.31-rc8-wl-34789-g95cb731-dirty # Call Trace: [<ffffffff8103e285>] __schedule_bug+0x85/0x90 [<ffffffff81403138>] schedule+0x108/0x588 [<ffffffff8135b131>] netlink_table_grab+0xa1/0xf0 [<ffffffff8135c3a7>] netlink_change_ngroups+0x47/0x100 [<ffffffff8135ef0f>] genl_register_mc_group+0x12f/0x290 because I overlooked that netlink_table_grab() will schedule, thinking it was just the rwlock. However, in the contention case, that isn't actually true. Fix this by letting the code grab the netlink table lock first and then the RCU for netns protection. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* netlink: silence compiler warningBrian Haley2009-09-04
| | | | | | | | | | | | CC net/netlink/genetlink.o net/netlink/genetlink.c: In function ‘genl_register_mc_group’: net/netlink/genetlink.c:139: warning: ‘err’ may be used uninitialized in this function From following the code 'err' is initialized, but set it to zero to silence the warning. Signed-off-by: Brian Haley <brian.haley@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* genetlink: make netns awareJohannes Berg2009-07-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This makes generic netlink network namespace aware. No generic netlink families except for the controller family are made namespace aware, they need to be checked one by one and then set the family->netnsok member to true. A new function genlmsg_multicast_netns() is introduced to allow sending a multicast message in a given namespace, for example when it applies to an object that lives in that namespace, a new function genlmsg_multicast_allns() to send a message to all network namespaces (for objects that do not have an associated netns). The function genlmsg_multicast() is changed to multicast the message in just init_net, which is currently correct for all generic netlink families since they only work in init_net right now. Some will later want to work in all net namespaces because they do not care about the netns at all -- those will have to be converted to use one of the new functions genlmsg_multicast_allns() or genlmsg_multicast_netns() whenever they are made netns aware in some way. After this patch families can easily decide whether or not they should be available in all net namespaces. Many genl families us it for objects not related to networking and should therefore be available in all namespaces, but that will have to be done on a per family basis. Note that this doesn't touch on the checkpoint/restart problem where network namespaces could be used, genl families and multicast groups are numbered globally and I see no easy way of changing that, especially since it must be possible to multicast to all network namespaces for those families that do not care about netns. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* genetlink: Introduce genl_register_family_with_ops()Michał Mirosław2009-05-21
| | | | | | | | | This introduces genl_register_family_with_ops() that registers a genetlink family along with operations from a table. This is used to kill copy'n'paste occurrences in following patches. Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl> Signed-off-by: David S. Miller <davem@davemloft.net>
* genetlink: export genl_unregister_mc_group()Inaky Perez-Gonzalez2009-01-07
| | | | | | | | | | | | | | | | | | | | Add an EXPORT_SYMBOL() to genl_unregister_mc_group(), to allow unregistering groups on the run. EXPORT_SYMBOL_GPL() is not used as the rest of the functions exported by this module (eg: genl_register_mc_group) are also not _GPL(). Cleanup is currently done when unregistering a family, but there is no way to unregister a single multicast group due to that function not being exported. Seems to be a mistake as it is documented as for external consumption. This is needed by the WiMAX stack to be able to cleanup unused mc groups. Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com> Acked-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* netlink: genl: fix circular lockingPatrick McHardy2008-06-18
| | | | | | | | | | | | | | | | | | | | | | | | | | genetlink has a circular locking dependency when dumping the registered families: - dump start: genl_rcv() : take genl_mutex genl_rcv_msg() : call netlink_dump_start() while holding genl_mutex netlink_dump_start(), netlink_dump() : take nlk->cb_mutex ctrl_dumpfamily() : try to detect this case and not take genl_mutex a second time - dump continuance: netlink_rcv() : call netlink_dump netlink_dump : take nlk->cb_mutex ctrl_dumpfamily() : take genl_mutex Register genl_lock as callback mutex with netlink to fix this. This slightly widens an already existing module unload race, the genl ops used during the dump might go away when the module is unloaded. Thomas Graf is working on a seperate fix for this. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* netlink: Improve returned error codesThomas Graf2008-06-03
| | | | | | | | | | | Make nlmsg_trim(), nlmsg_cancel(), genlmsg_cancel(), and nla_nest_cancel() void functions. Return -EMSGSIZE instead of -1 if the provided message buffer is not big enough. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [GENETLINK]: Relax dances with genl_lock.Pavel Emelyanov2008-02-13
| | | | | | | | | | | | The genl_unregister_family() calls the genl_unregister_mc_groups(), which takes and releases the genl_lock and then locks and releases this lock itself. Relax this behavior, all the more so the genl_unregister_mc_groups() is called from genl_unregister_family() only. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: make netlink user -> kernel interface synchroniousDenis V. Lunev2007-10-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch make processing netlink user -> kernel messages synchronious. This change was inspired by the talk with Alexey Kuznetsov about current netlink messages processing. He says that he was badly wrong when introduced asynchronious user -> kernel communication. The call netlink_unicast is the only path to send message to the kernel netlink socket. But, unfortunately, it is also used to send data to the user. Before this change the user message has been attached to the socket queue and sk->sk_data_ready was called. The process has been blocked until all pending messages were processed. The bad thing is that this processing may occur in the arbitrary process context. This patch changes nlk->data_ready callback to get 1 skb and force packet processing right in the netlink_unicast. Kernel -> user path in netlink_unicast remains untouched. EINTR processing for in netlink_run_queue was changed. It forces rtnl_lock drop, but the process remains in the cycle until the message will be fully processed. So, there is no need to use this kludges now. Signed-off-by: Denis V. Lunev <den@openvz.org> Acked-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: Make netlink processing routines semi-synchronious (inspired by rtnl) v2Denis V. Lunev2007-10-11
| | | | | | | | | | | | | The code in netfilter/nfnetlink.c and in ./net/netlink/genetlink.c looks like outdated copy/paste from rtnetlink.c. Push them into sync with the original. Changes from v1: - deleted comment in nfnetlink_rcv_msg by request of Patrick McHardy Signed-off-by: Denis V. Lunev <den@openvz.org> Acked-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK]: Avoid pointer in netlink_run_queueHerbert Xu2007-10-10
| | | | | | | | | | | I was looking at Patrick's fix to inet_diag and it occured to me that we're using a pointer argument to return values unnecessarily in netlink_run_queue. Changing it to return the value will allow the compiler to generate better code since the value won't have to be memory-backed. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: Support multiple network namespaces with netlinkEric W. Biederman2007-10-10
| | | | | | | | | | | | | | | | | | | | | Each netlink socket will live in exactly one network namespace, this includes the controlling kernel sockets. This patch updates all of the existing netlink protocols to only support the initial network namespace. Request by clients in other namespaces will get -ECONREFUSED. As they would if the kernel did not have the support for that netlink protocol compiled in. As each netlink protocol is updated to be multiple network namespace safe it can register multiple kernel sockets to acquire a presence in the rest of the network namespaces. The implementation in af_netlink is a simple filter implementation at hash table insertion and hash table look up time. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [GENETLINK]: Correctly report errors while registering a multicast groupThomas Graf2007-07-24
| | | | | Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [GENETLINK]: Fix adjustment of number of multicast groupsThomas Graf2007-07-24
| | | | | | | | The current calculation of the maximum number of genetlink multicast groups seems odd, fix it. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [GENETLINK]: Fix race in genl_unregister_mc_groups()Thomas Graf2007-07-24
| | | | | | | | | family->mcast_groups is protected by genl_lock so it must be held while accessing the list in genl_unregister_mc_groups(). Requires adding a non-locking variant of genl_unregister_mc_group(). Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [GENETLINK]: Dynamic multicast groups.Johannes Berg2007-07-18
| | | | | | | | | Introduce API to dynamically register and unregister multicast groups. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: Patrick McHardy <kaber@trash.net> Acked-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK]: Mark netlink policies constPatrick McHardy2007-06-07
| | | | | Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK]: Switch cb_lock spinlock to mutex and allow to override itPatrick McHardy2007-04-26
| | | | | | | | | | Switch cb_lock to mutex and allow netlink kernel users to override it with a subsystem specific mutex for consistent locking in dump callbacks. All netlink_dump_start users have been audited not to rely on any side-effects of the previously used spinlock. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK]: Directly return -EINTR from netlink_dump_start()Thomas Graf2007-04-26
| | | | | | | | | Now that all users of netlink_dump_start() use netlink_run_queue() to process the receive queue, it is possible to return -EINTR from netlink_dump_start() directly, therefore simplying the callers. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK]: Remove error pointer from netlink message handlerThomas Graf2007-04-26
| | | | | | | | | | | | | | | | | | The error pointer argument in netlink message handlers is used to signal the special case where processing has to be interrupted because a dump was started but no error happened. Instead it is simpler and more clear to return -EINTR and have netlink_run_queue() deal with getting the queue right. nfnetlink passed on this error pointer to its subsystem handlers but only uses it to signal the start of a netlink dump. Therefore it can be removed there as well. This patch also cleans up the error handling in the affected message handlers to be consistent since it had to be touched anyway. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK]: Ignore control messages directly in netlink_run_queue()Thomas Graf2007-04-26
| | | | | | | | Changes netlink_rcv_skb() to skip netlink controll messages and don't pass them on to the message handler. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK]: Ignore !NLM_F_REQUEST messages directly in netlink_run_queue()Thomas Graf2007-04-26
| | | | | | | | | netlink_rcv_skb() is changed to skip messages which don't have the NLM_F_REQUEST bit to avoid every netlink family having to perform this check on their own. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET] NETLINK: Fix whitespace errors.YOSHIFUJI Hideaki2007-02-11
| | | | | Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [GENETLINK]: Fix misplaced command flags.Jamal Hadi Salim2006-12-06
| | | | | | | The command flags for dump and do were swapped.. Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
* [GENETLINK]: Move command capabilities to flags.Jamal Hadi Salim2006-12-06
| | | | | | | | | | | This patch moves command capabilities to command flags. Other than being cleaner, saves several bytes. We increment the nlctrl version so as to signal to user space that to not expect the attributes. We will try to be careful not to do this too often ;-> Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
* [GENETLINK]: Add cmd dump completion.Jamal Hadi Salim2006-12-03
| | | | | | | | Remove assumption that generic netlink commands cannot have dump completion callbacks. Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
* [GENETLINK] ctrl: Avoid empty CTRL_ATTR_OPS attribute when dumpingThomas Graf2006-12-03
| | | | | | | Based on Jamal's patch but compiled and even tested. :-) Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [GENL]: Add genlmsg_put_reply() to simplify building reply headersThomas Graf2006-12-03
| | | | | | | | | | By modyfing genlmsg_put() to take a genl_family and by adding genlmsg_put_reply() the process of constructing the netlink and generic netlink headers is simplified. Signed-off-by: Thomas Graf <tgraf@suug.ch> Acked-by: Paul Moore <paul.moore@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [GENL]: Add genlmsg_reply() to simply unicast replies to requestsThomas Graf2006-12-03
| | | | | | | | | A generic netlink user has no interest in knowing how to address the source of the original request. Signed-off-by: Thomas Graf <tgraf@suug.ch> Acked-by: Paul Moore <paul.moore@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK]: Do precise netlink message allocations where possibleThomas Graf2006-12-03
| | | | | | | | | | | | | Account for the netlink message header size directly in nlmsg_new() instead of relying on the caller calculate it correctly. Replaces error handling of message construction functions when constructing notifications with bug traps since a failure implies a bug in calculating the size of the skb. Signed-off-by: Thomas Graf <tgraf@suug.ch> Acked-by: Paul Moore <paul.moore@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [GENL]: Provide more information to userspace about registered genl familiesThomas Graf2006-09-22
| | | | | | | | | | | | | | | | | | | | | | | | | | Additionaly exports the following information when providing the list of registered generic netlink families: - protocol version - header size - maximum number of attributes - list of available operations including - id - flags - avaiability of policy and doit/dumpit function libnl HEAD provides a utility to read this new information: 0x0010 nlctrl version 1 hdrsize 0 maxattr 6 op GETFAMILY (0x03) [POLICY,DOIT,DUMPIT] 0x0011 NLBL_MGMT version 1 hdrsize 0 maxattr 0 op unknown (0x02) [DOIT] op unknown (0x03) [DOIT] .... Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK]: Make use of NLA_STRING/NLA_NUL_STRING attribute validationThomas Graf2006-09-22
| | | | | | | | Converts existing NLA_STRING attributes to use the new validation features, saving a couple of temporary buffers. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK]: Add notification message sending interfaceThomas Graf2006-09-22
| | | | | | | | | | | | | | Adds nlmsg_notify() implementing proper notification logic. The message is multicasted to all listeners in the group. The applications the requests orignates from can request a unicast back report in which case said socket will be excluded from the multicast to avoid duplicated notifications. nlmsg_multicast() is extended to take allocation flags to allow notification in atomic contexts. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK]: Extend netlink messaging interfaceThomas Graf2006-09-22
| | | | | | | | | | | | | | Adds: nlmsg_get_pos() return current position in message nlmsg_trim() trim part of message nla_reserve_nohdr(skb, len) reserve room for an attribute w/o hdr nla_put_nohdr(skb, len, data) add attribute w/o hdr nla_find_nested() find attribute in nested attributes Fixes nlmsg_new() to take allocation flags and consider size. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* Remove obsolete #include <linux/config.h>Jörn Engel2006-06-30
| | | | | Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [NETLINK]: Encapsulate eff_cap usage within security framework.Darrel Goeddel2006-06-29
| | | | | | | | | | | | | | | | This patch encapsulates the usage of eff_cap (in netlink_skb_params) within the security framework by extending security_netlink_recv to include a required capability parameter and converting all direct usage of eff_caps outside of the lsm modules to use the interface. It also updates the SELinux implementation of the security_netlink_send and security_netlink_recv hooks to take advantage of the sid in the netlink_skb_params struct. This also enables SELinux to perform auditing of netlink capability checks. Please apply, for 2.6.18 if possible. Signed-off-by: Darrel Goeddel <dgoeddel@trustedcs.com> Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: James Morris <jmorris@namei.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] sem2mutex: misc static one-file mutexesIngo Molnar2006-03-26
| | | | | | | | | | | | | | | | | | | | | | Semaphore to mutex conversion. The conversion was generated via scripts, and the result was validated automatically via a script as well. Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Jens Axboe <axboe@suse.de> Cc: Neil Brown <neilb@cse.unsw.edu.au> Acked-by: Alasdair G Kergon <agk@redhat.com> Cc: Greg KH <greg@kroah.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Adam Belay <ambx1@neo.rr.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [NETLINK] genetlink: Fix bugs spotted by Andrew Morton.Jamal Hadi Salim2006-02-13
| | | | | | | | | | | | | | | | | | | - panic() doesn't return. - Don't forget to unlock on genl_register_family() error path - genl_rcv_msg() is called via pointer so there's no point in declaring it `inline'. Notes: genl_ctrl_event() ignores the genlmsg_multicast() return value. lots of things ignore the genl_ctrl_event() return value. Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] genetlink: don't touch module ref countPer Liden2006-01-13
| | | | | | | | | | | Increasing the module ref count at registration will block the module from ever being unloaded. In fact, genetlink should not care about the owner at all. This patch removes the owner field from the struct registered with genetlink. Signed-off-by: Per Liden <per.liden@ericsson.com> Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK] genetlink: fix cmd type in genl_ops to be consistent to u8Per Liden2006-01-03
| | | | | | Signed-off-by: Per Liden <per.liden@ericsson.com> ACKed-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK]: Generic netlink familyThomas Graf2005-11-09
The generic netlink family builds on top of netlink and provides simplifies access for the less demanding netlink users. It solves the problem of protocol numbers running out by introducing a so called controller taking care of id management and name resolving. Generic netlink modules register themself after filling out their id card (struct genl_family), after successful registration the modules are able to register callbacks to command numbers by filling out a struct genl_ops and calling genl_register_op(). The registered callbacks are invoked with attributes parsed making life of simple modules a lot easier. Although generic netlink modules can request static identifiers, it is recommended to use GENL_ID_GENERATE and to let the controller assign a unique identifier to the module. Userspace applications will then ask the controller and lookup the idenfier by the module name. Due to the current multicast implementation of netlink, the number of generic netlink modules is restricted to 1024 to avoid wasting memory for the per socket multiacst subscription bitmask. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
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