![Johannes Berg](/assets/img/avatar_default.png)
Contrary to common expectations for an "int" return, these functions return only a positive value -- if used correctly they cannot even return 0 because the message header will necessarily be in the skb. This makes the very common pattern of if (genlmsg_end(...) < 0) { ... } be a whole bunch of dead code. Many places also simply do return nlmsg_end(...); and the caller is expected to deal with it. This also commonly (at least for me) causes errors, because it is very common to write if (my_function(...)) /* error condition */ and if my_function() does "return nlmsg_end()" this is of course wrong. Additionally, there's not a single place in the kernel that actually needs the message length returned, and if anyone needs it later then it'll be very easy to just use skb->len there. Remove this, and make the functions void. This removes a bunch of dead code as described above. The patch adds lines because I did - return nlmsg_end(...); + nlmsg_end(...); + return 0; I could have preserved all the function's return values by returning skb->len, but instead I've audited all the places calling the affected functions and found that none cared. A few places actually compared the return value with <= 0 in dump functionality, but that could just be changed to < 0 with no change in behaviour, so I opted for the more efficient version. One instance of the error I've made numerous times now is also present in net/phonet/pn_netlink.c in the route_dumpit() function - it didn't check for <0 or <=0 and thus broke out of the loop every single time. I've preserved this since it will (I think) have caused the messages to userspace to be formatted differently with just a single message for every SKB returned to userspace. It's possible that this isn't needed for the tools that actually use this, but I don't even know what they are so couldn't test that changing this behaviour would be acceptable. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1153 lines
26 KiB
C
1153 lines
26 KiB
C
/*
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* NETLINK Generic Netlink Family
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*
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* Authors: Jamal Hadi Salim
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* Thomas Graf <tgraf@suug.ch>
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* Johannes Berg <johannes@sipsolutions.net>
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/errno.h>
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#include <linux/types.h>
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#include <linux/socket.h>
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#include <linux/string.h>
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#include <linux/skbuff.h>
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#include <linux/mutex.h>
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#include <linux/bitmap.h>
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#include <linux/rwsem.h>
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#include <net/sock.h>
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#include <net/genetlink.h>
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static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
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static DECLARE_RWSEM(cb_lock);
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void genl_lock(void)
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{
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mutex_lock(&genl_mutex);
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}
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EXPORT_SYMBOL(genl_lock);
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void genl_unlock(void)
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{
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mutex_unlock(&genl_mutex);
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}
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EXPORT_SYMBOL(genl_unlock);
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#ifdef CONFIG_LOCKDEP
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int lockdep_genl_is_held(void)
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{
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return lockdep_is_held(&genl_mutex);
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}
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EXPORT_SYMBOL(lockdep_genl_is_held);
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#endif
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static void genl_lock_all(void)
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{
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down_write(&cb_lock);
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genl_lock();
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}
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static void genl_unlock_all(void)
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{
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genl_unlock();
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up_write(&cb_lock);
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}
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#define GENL_FAM_TAB_SIZE 16
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#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
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static struct list_head family_ht[GENL_FAM_TAB_SIZE];
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/*
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* Bitmap of multicast groups that are currently in use.
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*
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* To avoid an allocation at boot of just one unsigned long,
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* declare it global instead.
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* Bit 0 is marked as already used since group 0 is invalid.
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* Bit 1 is marked as already used since the drop-monitor code
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* abuses the API and thinks it can statically use group 1.
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* That group will typically conflict with other groups that
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* any proper users use.
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* Bit 16 is marked as used since it's used for generic netlink
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* and the code no longer marks pre-reserved IDs as used.
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* Bit 17 is marked as already used since the VFS quota code
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* also abused this API and relied on family == group ID, we
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* cater to that by giving it a static family and group ID.
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* Bit 18 is marked as already used since the PMCRAID driver
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* did the same thing as the VFS quota code (maybe copied?)
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*/
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static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
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BIT(GENL_ID_VFS_DQUOT) |
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BIT(GENL_ID_PMCRAID);
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static unsigned long *mc_groups = &mc_group_start;
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static unsigned long mc_groups_longs = 1;
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static int genl_ctrl_event(int event, struct genl_family *family,
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const struct genl_multicast_group *grp,
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int grp_id);
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static inline unsigned int genl_family_hash(unsigned int id)
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{
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return id & GENL_FAM_TAB_MASK;
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}
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static inline struct list_head *genl_family_chain(unsigned int id)
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{
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return &family_ht[genl_family_hash(id)];
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}
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static struct genl_family *genl_family_find_byid(unsigned int id)
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{
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struct genl_family *f;
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list_for_each_entry(f, genl_family_chain(id), family_list)
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if (f->id == id)
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return f;
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return NULL;
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}
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static struct genl_family *genl_family_find_byname(char *name)
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{
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struct genl_family *f;
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int i;
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for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
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list_for_each_entry(f, genl_family_chain(i), family_list)
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if (strcmp(f->name, name) == 0)
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return f;
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return NULL;
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}
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static const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
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{
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int i;
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for (i = 0; i < family->n_ops; i++)
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if (family->ops[i].cmd == cmd)
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return &family->ops[i];
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return NULL;
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}
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/* Of course we are going to have problems once we hit
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* 2^16 alive types, but that can only happen by year 2K
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*/
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static u16 genl_generate_id(void)
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{
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static u16 id_gen_idx = GENL_MIN_ID;
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int i;
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for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
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if (id_gen_idx != GENL_ID_VFS_DQUOT &&
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id_gen_idx != GENL_ID_PMCRAID &&
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!genl_family_find_byid(id_gen_idx))
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return id_gen_idx;
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if (++id_gen_idx > GENL_MAX_ID)
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id_gen_idx = GENL_MIN_ID;
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}
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return 0;
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}
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static int genl_allocate_reserve_groups(int n_groups, int *first_id)
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{
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unsigned long *new_groups;
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int start = 0;
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int i;
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int id;
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bool fits;
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do {
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if (start == 0)
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id = find_first_zero_bit(mc_groups,
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mc_groups_longs *
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BITS_PER_LONG);
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else
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id = find_next_zero_bit(mc_groups,
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mc_groups_longs * BITS_PER_LONG,
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start);
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fits = true;
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for (i = id;
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i < min_t(int, id + n_groups,
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mc_groups_longs * BITS_PER_LONG);
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i++) {
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if (test_bit(i, mc_groups)) {
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start = i;
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fits = false;
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break;
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}
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}
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if (id >= mc_groups_longs * BITS_PER_LONG) {
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unsigned long new_longs = mc_groups_longs +
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BITS_TO_LONGS(n_groups);
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size_t nlen = new_longs * sizeof(unsigned long);
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if (mc_groups == &mc_group_start) {
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new_groups = kzalloc(nlen, GFP_KERNEL);
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if (!new_groups)
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return -ENOMEM;
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mc_groups = new_groups;
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*mc_groups = mc_group_start;
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} else {
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new_groups = krealloc(mc_groups, nlen,
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GFP_KERNEL);
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if (!new_groups)
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return -ENOMEM;
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mc_groups = new_groups;
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for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
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mc_groups[mc_groups_longs + i] = 0;
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}
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mc_groups_longs = new_longs;
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}
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} while (!fits);
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for (i = id; i < id + n_groups; i++)
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set_bit(i, mc_groups);
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*first_id = id;
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return 0;
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}
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static struct genl_family genl_ctrl;
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static int genl_validate_assign_mc_groups(struct genl_family *family)
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{
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int first_id;
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int n_groups = family->n_mcgrps;
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int err = 0, i;
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bool groups_allocated = false;
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if (!n_groups)
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return 0;
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for (i = 0; i < n_groups; i++) {
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const struct genl_multicast_group *grp = &family->mcgrps[i];
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if (WARN_ON(grp->name[0] == '\0'))
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return -EINVAL;
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if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
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return -EINVAL;
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}
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/* special-case our own group and hacks */
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if (family == &genl_ctrl) {
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first_id = GENL_ID_CTRL;
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BUG_ON(n_groups != 1);
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} else if (strcmp(family->name, "NET_DM") == 0) {
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first_id = 1;
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BUG_ON(n_groups != 1);
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} else if (family->id == GENL_ID_VFS_DQUOT) {
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first_id = GENL_ID_VFS_DQUOT;
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BUG_ON(n_groups != 1);
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} else if (family->id == GENL_ID_PMCRAID) {
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first_id = GENL_ID_PMCRAID;
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BUG_ON(n_groups != 1);
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} else {
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groups_allocated = true;
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err = genl_allocate_reserve_groups(n_groups, &first_id);
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if (err)
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return err;
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}
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family->mcgrp_offset = first_id;
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/* if still initializing, can't and don't need to to realloc bitmaps */
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if (!init_net.genl_sock)
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return 0;
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if (family->netnsok) {
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struct net *net;
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netlink_table_grab();
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rcu_read_lock();
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for_each_net_rcu(net) {
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err = __netlink_change_ngroups(net->genl_sock,
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mc_groups_longs * BITS_PER_LONG);
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if (err) {
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/*
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* No need to roll back, can only fail if
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* memory allocation fails and then the
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* number of _possible_ groups has been
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* increased on some sockets which is ok.
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*/
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break;
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}
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}
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rcu_read_unlock();
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netlink_table_ungrab();
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} else {
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err = netlink_change_ngroups(init_net.genl_sock,
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mc_groups_longs * BITS_PER_LONG);
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}
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if (groups_allocated && err) {
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for (i = 0; i < family->n_mcgrps; i++)
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clear_bit(family->mcgrp_offset + i, mc_groups);
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}
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return err;
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}
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static void genl_unregister_mc_groups(struct genl_family *family)
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{
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struct net *net;
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int i;
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netlink_table_grab();
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rcu_read_lock();
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for_each_net_rcu(net) {
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for (i = 0; i < family->n_mcgrps; i++)
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__netlink_clear_multicast_users(
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net->genl_sock, family->mcgrp_offset + i);
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}
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rcu_read_unlock();
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netlink_table_ungrab();
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for (i = 0; i < family->n_mcgrps; i++) {
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int grp_id = family->mcgrp_offset + i;
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if (grp_id != 1)
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clear_bit(grp_id, mc_groups);
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genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
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&family->mcgrps[i], grp_id);
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}
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}
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static int genl_validate_ops(const struct genl_family *family)
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{
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const struct genl_ops *ops = family->ops;
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unsigned int n_ops = family->n_ops;
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int i, j;
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if (WARN_ON(n_ops && !ops))
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return -EINVAL;
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if (!n_ops)
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return 0;
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for (i = 0; i < n_ops; i++) {
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if (ops[i].dumpit == NULL && ops[i].doit == NULL)
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return -EINVAL;
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for (j = i + 1; j < n_ops; j++)
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if (ops[i].cmd == ops[j].cmd)
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return -EINVAL;
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}
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return 0;
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}
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/**
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* __genl_register_family - register a generic netlink family
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* @family: generic netlink family
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*
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* Registers the specified family after validating it first. Only one
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* family may be registered with the same family name or identifier.
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* The family id may equal GENL_ID_GENERATE causing an unique id to
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* be automatically generated and assigned.
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*
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* The family's ops array must already be assigned, you can use the
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* genl_register_family_with_ops() helper function.
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*
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* Return 0 on success or a negative error code.
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*/
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int __genl_register_family(struct genl_family *family)
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{
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int err = -EINVAL, i;
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if (family->id && family->id < GENL_MIN_ID)
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goto errout;
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if (family->id > GENL_MAX_ID)
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goto errout;
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err = genl_validate_ops(family);
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if (err)
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return err;
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genl_lock_all();
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if (genl_family_find_byname(family->name)) {
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err = -EEXIST;
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goto errout_locked;
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}
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if (family->id == GENL_ID_GENERATE) {
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u16 newid = genl_generate_id();
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if (!newid) {
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err = -ENOMEM;
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goto errout_locked;
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}
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family->id = newid;
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} else if (genl_family_find_byid(family->id)) {
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err = -EEXIST;
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goto errout_locked;
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}
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if (family->maxattr && !family->parallel_ops) {
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family->attrbuf = kmalloc((family->maxattr+1) *
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sizeof(struct nlattr *), GFP_KERNEL);
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if (family->attrbuf == NULL) {
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err = -ENOMEM;
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goto errout_locked;
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}
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} else
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family->attrbuf = NULL;
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err = genl_validate_assign_mc_groups(family);
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if (err)
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goto errout_locked;
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list_add_tail(&family->family_list, genl_family_chain(family->id));
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genl_unlock_all();
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/* send all events */
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genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
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for (i = 0; i < family->n_mcgrps; i++)
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genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
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&family->mcgrps[i], family->mcgrp_offset + i);
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return 0;
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errout_locked:
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genl_unlock_all();
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errout:
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return err;
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}
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EXPORT_SYMBOL(__genl_register_family);
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/**
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* genl_unregister_family - unregister generic netlink family
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* @family: generic netlink family
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*
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* Unregisters the specified family.
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*
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* Returns 0 on success or a negative error code.
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*/
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int genl_unregister_family(struct genl_family *family)
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{
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struct genl_family *rc;
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genl_lock_all();
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genl_unregister_mc_groups(family);
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list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
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if (family->id != rc->id || strcmp(rc->name, family->name))
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continue;
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list_del(&rc->family_list);
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family->n_ops = 0;
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genl_unlock_all();
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kfree(family->attrbuf);
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genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
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return 0;
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}
|
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genl_unlock_all();
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|
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return -ENOENT;
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}
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EXPORT_SYMBOL(genl_unregister_family);
|
|
|
|
/**
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* genlmsg_new_unicast - Allocate generic netlink message for unicast
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* @payload: size of the message payload
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* @info: information on destination
|
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* @flags: the type of memory to allocate
|
|
*
|
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* Allocates a new sk_buff large enough to cover the specified payload
|
|
* plus required Netlink headers. Will check receiving socket for
|
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* memory mapped i/o capability and use it if enabled. Will fall back
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* to non-mapped skb if message size exceeds the frame size of the ring.
|
|
*/
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struct sk_buff *genlmsg_new_unicast(size_t payload, struct genl_info *info,
|
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gfp_t flags)
|
|
{
|
|
size_t len = nlmsg_total_size(genlmsg_total_size(payload));
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|
|
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return netlink_alloc_skb(info->dst_sk, len, info->snd_portid, flags);
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}
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|
EXPORT_SYMBOL_GPL(genlmsg_new_unicast);
|
|
|
|
/**
|
|
* genlmsg_put - Add generic netlink header to netlink message
|
|
* @skb: socket buffer holding the message
|
|
* @portid: netlink portid the message is addressed to
|
|
* @seq: sequence number (usually the one of the sender)
|
|
* @family: generic netlink family
|
|
* @flags: netlink message flags
|
|
* @cmd: generic netlink command
|
|
*
|
|
* Returns pointer to user specific header
|
|
*/
|
|
void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
|
|
struct genl_family *family, int flags, u8 cmd)
|
|
{
|
|
struct nlmsghdr *nlh;
|
|
struct genlmsghdr *hdr;
|
|
|
|
nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
|
|
family->hdrsize, flags);
|
|
if (nlh == NULL)
|
|
return NULL;
|
|
|
|
hdr = nlmsg_data(nlh);
|
|
hdr->cmd = cmd;
|
|
hdr->version = family->version;
|
|
hdr->reserved = 0;
|
|
|
|
return (char *) hdr + GENL_HDRLEN;
|
|
}
|
|
EXPORT_SYMBOL(genlmsg_put);
|
|
|
|
static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
|
|
{
|
|
/* our ops are always const - netlink API doesn't propagate that */
|
|
const struct genl_ops *ops = cb->data;
|
|
int rc;
|
|
|
|
genl_lock();
|
|
rc = ops->dumpit(skb, cb);
|
|
genl_unlock();
|
|
return rc;
|
|
}
|
|
|
|
static int genl_lock_done(struct netlink_callback *cb)
|
|
{
|
|
/* our ops are always const - netlink API doesn't propagate that */
|
|
const struct genl_ops *ops = cb->data;
|
|
int rc = 0;
|
|
|
|
if (ops->done) {
|
|
genl_lock();
|
|
rc = ops->done(cb);
|
|
genl_unlock();
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
static int genl_family_rcv_msg(struct genl_family *family,
|
|
struct sk_buff *skb,
|
|
struct nlmsghdr *nlh)
|
|
{
|
|
const struct genl_ops *ops;
|
|
struct net *net = sock_net(skb->sk);
|
|
struct genl_info info;
|
|
struct genlmsghdr *hdr = nlmsg_data(nlh);
|
|
struct nlattr **attrbuf;
|
|
int hdrlen, err;
|
|
|
|
/* this family doesn't exist in this netns */
|
|
if (!family->netnsok && !net_eq(net, &init_net))
|
|
return -ENOENT;
|
|
|
|
hdrlen = GENL_HDRLEN + family->hdrsize;
|
|
if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
|
|
return -EINVAL;
|
|
|
|
ops = genl_get_cmd(hdr->cmd, family);
|
|
if (ops == NULL)
|
|
return -EOPNOTSUPP;
|
|
|
|
if ((ops->flags & GENL_ADMIN_PERM) &&
|
|
!netlink_capable(skb, CAP_NET_ADMIN))
|
|
return -EPERM;
|
|
|
|
if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
|
|
int rc;
|
|
|
|
if (ops->dumpit == NULL)
|
|
return -EOPNOTSUPP;
|
|
|
|
if (!family->parallel_ops) {
|
|
struct netlink_dump_control c = {
|
|
.module = family->module,
|
|
/* we have const, but the netlink API doesn't */
|
|
.data = (void *)ops,
|
|
.dump = genl_lock_dumpit,
|
|
.done = genl_lock_done,
|
|
};
|
|
|
|
genl_unlock();
|
|
rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
|
|
genl_lock();
|
|
|
|
} else {
|
|
struct netlink_dump_control c = {
|
|
.module = family->module,
|
|
.dump = ops->dumpit,
|
|
.done = ops->done,
|
|
};
|
|
|
|
rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
if (ops->doit == NULL)
|
|
return -EOPNOTSUPP;
|
|
|
|
if (family->maxattr && family->parallel_ops) {
|
|
attrbuf = kmalloc((family->maxattr+1) *
|
|
sizeof(struct nlattr *), GFP_KERNEL);
|
|
if (attrbuf == NULL)
|
|
return -ENOMEM;
|
|
} else
|
|
attrbuf = family->attrbuf;
|
|
|
|
if (attrbuf) {
|
|
err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
|
|
ops->policy);
|
|
if (err < 0)
|
|
goto out;
|
|
}
|
|
|
|
info.snd_seq = nlh->nlmsg_seq;
|
|
info.snd_portid = NETLINK_CB(skb).portid;
|
|
info.nlhdr = nlh;
|
|
info.genlhdr = nlmsg_data(nlh);
|
|
info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
|
|
info.attrs = attrbuf;
|
|
info.dst_sk = skb->sk;
|
|
genl_info_net_set(&info, net);
|
|
memset(&info.user_ptr, 0, sizeof(info.user_ptr));
|
|
|
|
if (family->pre_doit) {
|
|
err = family->pre_doit(ops, skb, &info);
|
|
if (err)
|
|
goto out;
|
|
}
|
|
|
|
err = ops->doit(skb, &info);
|
|
|
|
if (family->post_doit)
|
|
family->post_doit(ops, skb, &info);
|
|
|
|
out:
|
|
if (family->parallel_ops)
|
|
kfree(attrbuf);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
|
|
{
|
|
struct genl_family *family;
|
|
int err;
|
|
|
|
family = genl_family_find_byid(nlh->nlmsg_type);
|
|
if (family == NULL)
|
|
return -ENOENT;
|
|
|
|
if (!family->parallel_ops)
|
|
genl_lock();
|
|
|
|
err = genl_family_rcv_msg(family, skb, nlh);
|
|
|
|
if (!family->parallel_ops)
|
|
genl_unlock();
|
|
|
|
return err;
|
|
}
|
|
|
|
static void genl_rcv(struct sk_buff *skb)
|
|
{
|
|
down_read(&cb_lock);
|
|
netlink_rcv_skb(skb, &genl_rcv_msg);
|
|
up_read(&cb_lock);
|
|
}
|
|
|
|
/**************************************************************************
|
|
* Controller
|
|
**************************************************************************/
|
|
|
|
static struct genl_family genl_ctrl = {
|
|
.id = GENL_ID_CTRL,
|
|
.name = "nlctrl",
|
|
.version = 0x2,
|
|
.maxattr = CTRL_ATTR_MAX,
|
|
.netnsok = true,
|
|
};
|
|
|
|
static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
|
|
u32 flags, struct sk_buff *skb, u8 cmd)
|
|
{
|
|
void *hdr;
|
|
|
|
hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
|
|
if (hdr == NULL)
|
|
return -1;
|
|
|
|
if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
|
|
nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
|
|
nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
|
|
nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
|
|
nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
|
|
goto nla_put_failure;
|
|
|
|
if (family->n_ops) {
|
|
struct nlattr *nla_ops;
|
|
int i;
|
|
|
|
nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
|
|
if (nla_ops == NULL)
|
|
goto nla_put_failure;
|
|
|
|
for (i = 0; i < family->n_ops; i++) {
|
|
struct nlattr *nest;
|
|
const struct genl_ops *ops = &family->ops[i];
|
|
u32 op_flags = ops->flags;
|
|
|
|
if (ops->dumpit)
|
|
op_flags |= GENL_CMD_CAP_DUMP;
|
|
if (ops->doit)
|
|
op_flags |= GENL_CMD_CAP_DO;
|
|
if (ops->policy)
|
|
op_flags |= GENL_CMD_CAP_HASPOL;
|
|
|
|
nest = nla_nest_start(skb, i + 1);
|
|
if (nest == NULL)
|
|
goto nla_put_failure;
|
|
|
|
if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
|
|
nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
|
|
goto nla_put_failure;
|
|
|
|
nla_nest_end(skb, nest);
|
|
}
|
|
|
|
nla_nest_end(skb, nla_ops);
|
|
}
|
|
|
|
if (family->n_mcgrps) {
|
|
struct nlattr *nla_grps;
|
|
int i;
|
|
|
|
nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
|
|
if (nla_grps == NULL)
|
|
goto nla_put_failure;
|
|
|
|
for (i = 0; i < family->n_mcgrps; i++) {
|
|
struct nlattr *nest;
|
|
const struct genl_multicast_group *grp;
|
|
|
|
grp = &family->mcgrps[i];
|
|
|
|
nest = nla_nest_start(skb, i + 1);
|
|
if (nest == NULL)
|
|
goto nla_put_failure;
|
|
|
|
if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
|
|
family->mcgrp_offset + i) ||
|
|
nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
|
|
grp->name))
|
|
goto nla_put_failure;
|
|
|
|
nla_nest_end(skb, nest);
|
|
}
|
|
nla_nest_end(skb, nla_grps);
|
|
}
|
|
|
|
genlmsg_end(skb, hdr);
|
|
return 0;
|
|
|
|
nla_put_failure:
|
|
genlmsg_cancel(skb, hdr);
|
|
return -EMSGSIZE;
|
|
}
|
|
|
|
static int ctrl_fill_mcgrp_info(struct genl_family *family,
|
|
const struct genl_multicast_group *grp,
|
|
int grp_id, u32 portid, u32 seq, u32 flags,
|
|
struct sk_buff *skb, u8 cmd)
|
|
{
|
|
void *hdr;
|
|
struct nlattr *nla_grps;
|
|
struct nlattr *nest;
|
|
|
|
hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
|
|
if (hdr == NULL)
|
|
return -1;
|
|
|
|
if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
|
|
nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
|
|
goto nla_put_failure;
|
|
|
|
nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
|
|
if (nla_grps == NULL)
|
|
goto nla_put_failure;
|
|
|
|
nest = nla_nest_start(skb, 1);
|
|
if (nest == NULL)
|
|
goto nla_put_failure;
|
|
|
|
if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
|
|
nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
|
|
grp->name))
|
|
goto nla_put_failure;
|
|
|
|
nla_nest_end(skb, nest);
|
|
nla_nest_end(skb, nla_grps);
|
|
|
|
genlmsg_end(skb, hdr);
|
|
return 0;
|
|
|
|
nla_put_failure:
|
|
genlmsg_cancel(skb, hdr);
|
|
return -EMSGSIZE;
|
|
}
|
|
|
|
static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
|
|
{
|
|
|
|
int i, n = 0;
|
|
struct genl_family *rt;
|
|
struct net *net = sock_net(skb->sk);
|
|
int chains_to_skip = cb->args[0];
|
|
int fams_to_skip = cb->args[1];
|
|
|
|
for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
|
|
n = 0;
|
|
list_for_each_entry(rt, genl_family_chain(i), family_list) {
|
|
if (!rt->netnsok && !net_eq(net, &init_net))
|
|
continue;
|
|
if (++n < fams_to_skip)
|
|
continue;
|
|
if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
|
|
cb->nlh->nlmsg_seq, NLM_F_MULTI,
|
|
skb, CTRL_CMD_NEWFAMILY) < 0)
|
|
goto errout;
|
|
}
|
|
|
|
fams_to_skip = 0;
|
|
}
|
|
|
|
errout:
|
|
cb->args[0] = i;
|
|
cb->args[1] = n;
|
|
|
|
return skb->len;
|
|
}
|
|
|
|
static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
|
|
u32 portid, int seq, u8 cmd)
|
|
{
|
|
struct sk_buff *skb;
|
|
int err;
|
|
|
|
skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
|
|
if (skb == NULL)
|
|
return ERR_PTR(-ENOBUFS);
|
|
|
|
err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
|
|
if (err < 0) {
|
|
nlmsg_free(skb);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
return skb;
|
|
}
|
|
|
|
static struct sk_buff *
|
|
ctrl_build_mcgrp_msg(struct genl_family *family,
|
|
const struct genl_multicast_group *grp,
|
|
int grp_id, u32 portid, int seq, u8 cmd)
|
|
{
|
|
struct sk_buff *skb;
|
|
int err;
|
|
|
|
skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
|
|
if (skb == NULL)
|
|
return ERR_PTR(-ENOBUFS);
|
|
|
|
err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
|
|
seq, 0, skb, cmd);
|
|
if (err < 0) {
|
|
nlmsg_free(skb);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
return skb;
|
|
}
|
|
|
|
static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
|
|
[CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
|
|
[CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
|
|
.len = GENL_NAMSIZ - 1 },
|
|
};
|
|
|
|
static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
|
|
{
|
|
struct sk_buff *msg;
|
|
struct genl_family *res = NULL;
|
|
int err = -EINVAL;
|
|
|
|
if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
|
|
u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
|
|
res = genl_family_find_byid(id);
|
|
err = -ENOENT;
|
|
}
|
|
|
|
if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
|
|
char *name;
|
|
|
|
name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
|
|
res = genl_family_find_byname(name);
|
|
#ifdef CONFIG_MODULES
|
|
if (res == NULL) {
|
|
genl_unlock();
|
|
up_read(&cb_lock);
|
|
request_module("net-pf-%d-proto-%d-family-%s",
|
|
PF_NETLINK, NETLINK_GENERIC, name);
|
|
down_read(&cb_lock);
|
|
genl_lock();
|
|
res = genl_family_find_byname(name);
|
|
}
|
|
#endif
|
|
err = -ENOENT;
|
|
}
|
|
|
|
if (res == NULL)
|
|
return err;
|
|
|
|
if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
|
|
/* family doesn't exist here */
|
|
return -ENOENT;
|
|
}
|
|
|
|
msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
|
|
CTRL_CMD_NEWFAMILY);
|
|
if (IS_ERR(msg))
|
|
return PTR_ERR(msg);
|
|
|
|
return genlmsg_reply(msg, info);
|
|
}
|
|
|
|
static int genl_ctrl_event(int event, struct genl_family *family,
|
|
const struct genl_multicast_group *grp,
|
|
int grp_id)
|
|
{
|
|
struct sk_buff *msg;
|
|
|
|
/* genl is still initialising */
|
|
if (!init_net.genl_sock)
|
|
return 0;
|
|
|
|
switch (event) {
|
|
case CTRL_CMD_NEWFAMILY:
|
|
case CTRL_CMD_DELFAMILY:
|
|
WARN_ON(grp);
|
|
msg = ctrl_build_family_msg(family, 0, 0, event);
|
|
break;
|
|
case CTRL_CMD_NEWMCAST_GRP:
|
|
case CTRL_CMD_DELMCAST_GRP:
|
|
BUG_ON(!grp);
|
|
msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (IS_ERR(msg))
|
|
return PTR_ERR(msg);
|
|
|
|
if (!family->netnsok) {
|
|
genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
|
|
0, GFP_KERNEL);
|
|
} else {
|
|
rcu_read_lock();
|
|
genlmsg_multicast_allns(&genl_ctrl, msg, 0,
|
|
0, GFP_ATOMIC);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct genl_ops genl_ctrl_ops[] = {
|
|
{
|
|
.cmd = CTRL_CMD_GETFAMILY,
|
|
.doit = ctrl_getfamily,
|
|
.dumpit = ctrl_dumpfamily,
|
|
.policy = ctrl_policy,
|
|
},
|
|
};
|
|
|
|
static struct genl_multicast_group genl_ctrl_groups[] = {
|
|
{ .name = "notify", },
|
|
};
|
|
|
|
static int genl_bind(struct net *net, int group)
|
|
{
|
|
int i, err = 0;
|
|
|
|
down_read(&cb_lock);
|
|
for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
|
|
struct genl_family *f;
|
|
|
|
list_for_each_entry(f, genl_family_chain(i), family_list) {
|
|
if (group >= f->mcgrp_offset &&
|
|
group < f->mcgrp_offset + f->n_mcgrps) {
|
|
int fam_grp = group - f->mcgrp_offset;
|
|
|
|
if (!f->netnsok && net != &init_net)
|
|
err = -ENOENT;
|
|
else if (f->mcast_bind)
|
|
err = f->mcast_bind(net, fam_grp);
|
|
else
|
|
err = 0;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
up_read(&cb_lock);
|
|
|
|
return err;
|
|
}
|
|
|
|
static void genl_unbind(struct net *net, int group)
|
|
{
|
|
int i;
|
|
bool found = false;
|
|
|
|
down_read(&cb_lock);
|
|
for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
|
|
struct genl_family *f;
|
|
|
|
list_for_each_entry(f, genl_family_chain(i), family_list) {
|
|
if (group >= f->mcgrp_offset &&
|
|
group < f->mcgrp_offset + f->n_mcgrps) {
|
|
int fam_grp = group - f->mcgrp_offset;
|
|
|
|
if (f->mcast_unbind)
|
|
f->mcast_unbind(net, fam_grp);
|
|
found = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
up_read(&cb_lock);
|
|
|
|
WARN_ON(!found);
|
|
}
|
|
|
|
static int __net_init genl_pernet_init(struct net *net)
|
|
{
|
|
struct netlink_kernel_cfg cfg = {
|
|
.input = genl_rcv,
|
|
.flags = NL_CFG_F_NONROOT_RECV,
|
|
.bind = genl_bind,
|
|
.unbind = genl_unbind,
|
|
};
|
|
|
|
/* we'll bump the group number right afterwards */
|
|
net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
|
|
|
|
if (!net->genl_sock && net_eq(net, &init_net))
|
|
panic("GENL: Cannot initialize generic netlink\n");
|
|
|
|
if (!net->genl_sock)
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void __net_exit genl_pernet_exit(struct net *net)
|
|
{
|
|
netlink_kernel_release(net->genl_sock);
|
|
net->genl_sock = NULL;
|
|
}
|
|
|
|
static struct pernet_operations genl_pernet_ops = {
|
|
.init = genl_pernet_init,
|
|
.exit = genl_pernet_exit,
|
|
};
|
|
|
|
static int __init genl_init(void)
|
|
{
|
|
int i, err;
|
|
|
|
for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
|
|
INIT_LIST_HEAD(&family_ht[i]);
|
|
|
|
err = genl_register_family_with_ops_groups(&genl_ctrl, genl_ctrl_ops,
|
|
genl_ctrl_groups);
|
|
if (err < 0)
|
|
goto problem;
|
|
|
|
err = register_pernet_subsys(&genl_pernet_ops);
|
|
if (err)
|
|
goto problem;
|
|
|
|
return 0;
|
|
|
|
problem:
|
|
panic("GENL: Cannot register controller: %d\n", err);
|
|
}
|
|
|
|
subsys_initcall(genl_init);
|
|
|
|
static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
|
|
gfp_t flags)
|
|
{
|
|
struct sk_buff *tmp;
|
|
struct net *net, *prev = NULL;
|
|
int err;
|
|
|
|
for_each_net_rcu(net) {
|
|
if (prev) {
|
|
tmp = skb_clone(skb, flags);
|
|
if (!tmp) {
|
|
err = -ENOMEM;
|
|
goto error;
|
|
}
|
|
err = nlmsg_multicast(prev->genl_sock, tmp,
|
|
portid, group, flags);
|
|
if (err)
|
|
goto error;
|
|
}
|
|
|
|
prev = net;
|
|
}
|
|
|
|
return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
|
|
error:
|
|
kfree_skb(skb);
|
|
return err;
|
|
}
|
|
|
|
int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb,
|
|
u32 portid, unsigned int group, gfp_t flags)
|
|
{
|
|
if (WARN_ON_ONCE(group >= family->n_mcgrps))
|
|
return -EINVAL;
|
|
group = family->mcgrp_offset + group;
|
|
return genlmsg_mcast(skb, portid, group, flags);
|
|
}
|
|
EXPORT_SYMBOL(genlmsg_multicast_allns);
|
|
|
|
void genl_notify(struct genl_family *family,
|
|
struct sk_buff *skb, struct net *net, u32 portid, u32 group,
|
|
struct nlmsghdr *nlh, gfp_t flags)
|
|
{
|
|
struct sock *sk = net->genl_sock;
|
|
int report = 0;
|
|
|
|
if (nlh)
|
|
report = nlmsg_report(nlh);
|
|
|
|
if (WARN_ON_ONCE(group >= family->n_mcgrps))
|
|
return;
|
|
group = family->mcgrp_offset + group;
|
|
nlmsg_notify(sk, skb, portid, group, report, flags);
|
|
}
|
|
EXPORT_SYMBOL(genl_notify);
|