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authorJohannes Berg <johannes@sipsolutions.net>2007-07-18 18:47:52 -0400
committerDavid S. Miller <davem@davemloft.net>2007-07-18 18:47:52 -0400
commit2dbba6f773d1e1e4c78f03b0dbf19790d9017693 (patch)
tree19535af46e79a0af756275f751d7b0080b72001d /net
parent84659eb529b33572bb3f8c94e0978bd5d084bc7e (diff)
[GENETLINK]: Dynamic multicast groups.
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>
Diffstat (limited to 'net')
-rw-r--r--net/netlink/genetlink.c235
1 files changed, 228 insertions, 7 deletions
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index b9ab62f938d0..e146531faf1d 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -3,6 +3,7 @@
3 * 3 *
4 * Authors: Jamal Hadi Salim 4 * Authors: Jamal Hadi Salim
5 * Thomas Graf <tgraf@suug.ch> 5 * Thomas Graf <tgraf@suug.ch>
6 * Johannes Berg <johannes@sipsolutions.net>
6 */ 7 */
7 8
8#include <linux/module.h> 9#include <linux/module.h>
@@ -13,6 +14,7 @@
13#include <linux/string.h> 14#include <linux/string.h>
14#include <linux/skbuff.h> 15#include <linux/skbuff.h>
15#include <linux/mutex.h> 16#include <linux/mutex.h>
17#include <linux/bitmap.h>
16#include <net/sock.h> 18#include <net/sock.h>
17#include <net/genetlink.h> 19#include <net/genetlink.h>
18 20
@@ -42,6 +44,16 @@ static void genl_unlock(void)
42#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1) 44#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
43 45
44static struct list_head family_ht[GENL_FAM_TAB_SIZE]; 46static struct list_head family_ht[GENL_FAM_TAB_SIZE];
47/*
48 * Bitmap of multicast groups that are currently in use.
49 *
50 * To avoid an allocation at boot of just one unsigned long,
51 * declare it global instead.
52 * Bit 0 is marked as already used since group 0 is invalid.
53 */
54static unsigned long mc_group_start = 0x1;
55static unsigned long *mc_groups = &mc_group_start;
56static unsigned long mc_groups_longs = 1;
45 57
46static int genl_ctrl_event(int event, void *data); 58static int genl_ctrl_event(int event, void *data);
47 59
@@ -116,6 +128,114 @@ static inline u16 genl_generate_id(void)
116 return id_gen_idx; 128 return id_gen_idx;
117} 129}
118 130
131static struct genl_multicast_group notify_grp;
132
133/**
134 * genl_register_mc_group - register a multicast group
135 *
136 * Registers the specified multicast group and notifies userspace
137 * about the new group.
138 *
139 * Returns 0 on success or a negative error code.
140 *
141 * @family: The generic netlink family the group shall be registered for.
142 * @grp: The group to register, must have a name.
143 */
144int genl_register_mc_group(struct genl_family *family,
145 struct genl_multicast_group *grp)
146{
147 int id;
148 unsigned long *new_groups;
149 int err;
150
151 BUG_ON(grp->name[0] == '\0');
152
153 genl_lock();
154
155 /* special-case our own group */
156 if (grp == &notify_grp)
157 id = GENL_ID_CTRL;
158 else
159 id = find_first_zero_bit(mc_groups,
160 mc_groups_longs * BITS_PER_LONG);
161
162
163 if (id >= mc_groups_longs * BITS_PER_LONG) {
164 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
165
166 if (mc_groups == &mc_group_start) {
167 new_groups = kzalloc(nlen, GFP_KERNEL);
168 if (!new_groups) {
169 err = -ENOMEM;
170 goto out;
171 }
172 mc_groups = new_groups;
173 *mc_groups = mc_group_start;
174 } else {
175 new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
176 if (!new_groups) {
177 err = -ENOMEM;
178 goto out;
179 }
180 mc_groups = new_groups;
181 mc_groups[mc_groups_longs] = 0;
182 }
183 mc_groups_longs++;
184 }
185
186 err = netlink_change_ngroups(genl_sock,
187 sizeof(unsigned long) * NETLINK_GENERIC);
188 if (err)
189 goto out;
190
191 grp->id = id;
192 set_bit(id, mc_groups);
193 list_add_tail(&grp->list, &family->mcast_groups);
194 grp->family = family;
195
196 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
197 out:
198 genl_unlock();
199 return 0;
200}
201EXPORT_SYMBOL(genl_register_mc_group);
202
203/**
204 * genl_unregister_mc_group - unregister a multicast group
205 *
206 * Unregisters the specified multicast group and notifies userspace
207 * about it. All current listeners on the group are removed.
208 *
209 * Note: It is not necessary to unregister all multicast groups before
210 * unregistering the family, unregistering the family will cause
211 * all assigned multicast groups to be unregistered automatically.
212 *
213 * @family: Generic netlink family the group belongs to.
214 * @grp: The group to unregister, must have been registered successfully
215 * previously.
216 */
217void genl_unregister_mc_group(struct genl_family *family,
218 struct genl_multicast_group *grp)
219{
220 BUG_ON(grp->family != family);
221 genl_lock();
222 netlink_clear_multicast_users(genl_sock, grp->id);
223 clear_bit(grp->id, mc_groups);
224 list_del(&grp->list);
225 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
226 grp->id = 0;
227 grp->family = NULL;
228 genl_unlock();
229}
230
231static void genl_unregister_mc_groups(struct genl_family *family)
232{
233 struct genl_multicast_group *grp, *tmp;
234
235 list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
236 genl_unregister_mc_group(family, grp);
237}
238
119/** 239/**
120 * genl_register_ops - register generic netlink operations 240 * genl_register_ops - register generic netlink operations
121 * @family: generic netlink family 241 * @family: generic netlink family
@@ -216,6 +336,7 @@ int genl_register_family(struct genl_family *family)
216 goto errout; 336 goto errout;
217 337
218 INIT_LIST_HEAD(&family->ops_list); 338 INIT_LIST_HEAD(&family->ops_list);
339 INIT_LIST_HEAD(&family->mcast_groups);
219 340
220 genl_lock(); 341 genl_lock();
221 342
@@ -275,6 +396,8 @@ int genl_unregister_family(struct genl_family *family)
275{ 396{
276 struct genl_family *rc; 397 struct genl_family *rc;
277 398
399 genl_unregister_mc_groups(family);
400
278 genl_lock(); 401 genl_lock();
279 402
280 list_for_each_entry(rc, genl_family_chain(family->id), family_list) { 403 list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
@@ -410,6 +533,67 @@ static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
410 nla_nest_end(skb, nla_ops); 533 nla_nest_end(skb, nla_ops);
411 } 534 }
412 535
536 if (!list_empty(&family->mcast_groups)) {
537 struct genl_multicast_group *grp;
538 struct nlattr *nla_grps;
539 int idx = 1;
540
541 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
542 if (nla_grps == NULL)
543 goto nla_put_failure;
544
545 list_for_each_entry(grp, &family->mcast_groups, list) {
546 struct nlattr *nest;
547
548 nest = nla_nest_start(skb, idx++);
549 if (nest == NULL)
550 goto nla_put_failure;
551
552 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
553 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
554 grp->name);
555
556 nla_nest_end(skb, nest);
557 }
558 nla_nest_end(skb, nla_grps);
559 }
560
561 return genlmsg_end(skb, hdr);
562
563nla_put_failure:
564 return genlmsg_cancel(skb, hdr);
565}
566
567static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
568 u32 seq, u32 flags, struct sk_buff *skb,
569 u8 cmd)
570{
571 void *hdr;
572 struct nlattr *nla_grps;
573 struct nlattr *nest;
574
575 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
576 if (hdr == NULL)
577 return -1;
578
579 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
580 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
581
582 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
583 if (nla_grps == NULL)
584 goto nla_put_failure;
585
586 nest = nla_nest_start(skb, 1);
587 if (nest == NULL)
588 goto nla_put_failure;
589
590 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
591 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
592 grp->name);
593
594 nla_nest_end(skb, nest);
595 nla_nest_end(skb, nla_grps);
596
413 return genlmsg_end(skb, hdr); 597 return genlmsg_end(skb, hdr);
414 598
415nla_put_failure: 599nla_put_failure:
@@ -453,8 +637,8 @@ errout:
453 return skb->len; 637 return skb->len;
454} 638}
455 639
456static struct sk_buff *ctrl_build_msg(struct genl_family *family, u32 pid, 640static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
457 int seq, u8 cmd) 641 u32 pid, int seq, u8 cmd)
458{ 642{
459 struct sk_buff *skb; 643 struct sk_buff *skb;
460 int err; 644 int err;
@@ -472,6 +656,25 @@ static struct sk_buff *ctrl_build_msg(struct genl_family *family, u32 pid,
472 return skb; 656 return skb;
473} 657}
474 658
659static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
660 u32 pid, int seq, u8 cmd)
661{
662 struct sk_buff *skb;
663 int err;
664
665 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
666 if (skb == NULL)
667 return ERR_PTR(-ENOBUFS);
668
669 err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
670 if (err < 0) {
671 nlmsg_free(skb);
672 return ERR_PTR(err);
673 }
674
675 return skb;
676}
677
475static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { 678static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
476 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, 679 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
477 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, 680 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
@@ -501,8 +704,8 @@ static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
501 goto errout; 704 goto errout;
502 } 705 }
503 706
504 msg = ctrl_build_msg(res, info->snd_pid, info->snd_seq, 707 msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
505 CTRL_CMD_NEWFAMILY); 708 CTRL_CMD_NEWFAMILY);
506 if (IS_ERR(msg)) { 709 if (IS_ERR(msg)) {
507 err = PTR_ERR(msg); 710 err = PTR_ERR(msg);
508 goto errout; 711 goto errout;
@@ -523,7 +726,15 @@ static int genl_ctrl_event(int event, void *data)
523 switch (event) { 726 switch (event) {
524 case CTRL_CMD_NEWFAMILY: 727 case CTRL_CMD_NEWFAMILY:
525 case CTRL_CMD_DELFAMILY: 728 case CTRL_CMD_DELFAMILY:
526 msg = ctrl_build_msg(data, 0, 0, event); 729 msg = ctrl_build_family_msg(data, 0, 0, event);
730 if (IS_ERR(msg))
731 return PTR_ERR(msg);
732
733 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
734 break;
735 case CTRL_CMD_NEWMCAST_GRP:
736 case CTRL_CMD_DELMCAST_GRP:
737 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
527 if (IS_ERR(msg)) 738 if (IS_ERR(msg))
528 return PTR_ERR(msg); 739 return PTR_ERR(msg);
529 740
@@ -541,6 +752,10 @@ static struct genl_ops genl_ctrl_ops = {
541 .policy = ctrl_policy, 752 .policy = ctrl_policy,
542}; 753};
543 754
755static struct genl_multicast_group notify_grp = {
756 .name = "notify",
757};
758
544static int __init genl_init(void) 759static int __init genl_init(void)
545{ 760{
546 int i, err; 761 int i, err;
@@ -557,11 +772,17 @@ static int __init genl_init(void)
557 goto errout_register; 772 goto errout_register;
558 773
559 netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV); 774 netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
560 genl_sock = netlink_kernel_create(NETLINK_GENERIC, GENL_MAX_ID, 775
561 genl_rcv, NULL, THIS_MODULE); 776 /* we'll bump the group number right afterwards */
777 genl_sock = netlink_kernel_create(NETLINK_GENERIC, 0, genl_rcv,
778 NULL, THIS_MODULE);
562 if (genl_sock == NULL) 779 if (genl_sock == NULL)
563 panic("GENL: Cannot initialize generic netlink\n"); 780 panic("GENL: Cannot initialize generic netlink\n");
564 781
782 err = genl_register_mc_group(&genl_ctrl, &notify_grp);
783 if (err < 0)
784 goto errout_register;
785
565 return 0; 786 return 0;
566 787
567errout_register: 788errout_register: