cregit-Linux how code gets into the kernel

Release 4.8 net/netlink/genetlink.c

Directory: net/netlink
/*
 * NETLINK      Generic Netlink Family
 *
 *              Authors:        Jamal Hadi Salim
 *                              Thomas Graf <tgraf@suug.ch>
 *                              Johannes Berg <johannes@sipsolutions.net>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/mutex.h>
#include <linux/bitmap.h>
#include <linux/rwsem.h>
#include <net/sock.h>
#include <net/genetlink.h>

static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
static DECLARE_RWSEM(cb_lock);


atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);

DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);


void genl_lock(void) { mutex_lock(&genl_mutex); }

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PersonTokensPropCommitsCommitProp
thomas grafthomas graf1184.62%150.00%
ingo molnaringo molnar215.38%150.00%
Total13100.00%2100.00%

EXPORT_SYMBOL(genl_lock);
void genl_unlock(void) { mutex_unlock(&genl_mutex); }

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PersonTokensPropCommitsCommitProp
thomas grafthomas graf1184.62%150.00%
ingo molnaringo molnar215.38%150.00%
Total13100.00%2100.00%

EXPORT_SYMBOL(genl_unlock); #ifdef CONFIG_LOCKDEP
bool lockdep_genl_is_held(void) { return lockdep_is_held(&genl_mutex); }

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PersonTokensPropCommitsCommitProp
pravin b shelarpravin b shelar1392.86%150.00%
yaowei baiyaowei bai17.14%150.00%
Total14100.00%2100.00%

EXPORT_SYMBOL(lockdep_genl_is_held); #endif
static void genl_lock_all(void) { down_write(&cb_lock); genl_lock(); }

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PersonTokensPropCommitsCommitProp
pravin b shelarpravin b shelar17100.00%1100.00%
Total17100.00%1100.00%


static void genl_unlock_all(void) { genl_unlock(); up_write(&cb_lock); }

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PersonTokensPropCommitsCommitProp
pravin b shelarpravin b shelar17100.00%1100.00%
Total17100.00%1100.00%

#define GENL_FAM_TAB_SIZE 16 #define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1) static struct list_head family_ht[GENL_FAM_TAB_SIZE]; /* * Bitmap of multicast groups that are currently in use. * * To avoid an allocation at boot of just one unsigned long, * declare it global instead. * Bit 0 is marked as already used since group 0 is invalid. * Bit 1 is marked as already used since the drop-monitor code * abuses the API and thinks it can statically use group 1. * That group will typically conflict with other groups that * any proper users use. * Bit 16 is marked as used since it's used for generic netlink * and the code no longer marks pre-reserved IDs as used. * Bit 17 is marked as already used since the VFS quota code * also abused this API and relied on family == group ID, we * cater to that by giving it a static family and group ID. * Bit 18 is marked as already used since the PMCRAID driver * did the same thing as the VFS quota code (maybe copied?) */ static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) | BIT(GENL_ID_VFS_DQUOT) | BIT(GENL_ID_PMCRAID); static unsigned long *mc_groups = &mc_group_start; static unsigned long mc_groups_longs = 1; static int genl_ctrl_event(int event, struct genl_family *family, const struct genl_multicast_group *grp, int grp_id);
static inline unsigned int genl_family_hash(unsigned int id) { return id & GENL_FAM_TAB_MASK; }

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PersonTokensPropCommitsCommitProp
thomas grafthomas graf17100.00%1100.00%
Total17100.00%1100.00%


static inline struct list_head *genl_family_chain(unsigned int id) { return &family_ht[genl_family_hash(id)]; }

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PersonTokensPropCommitsCommitProp
thomas grafthomas graf23100.00%1100.00%
Total23100.00%1100.00%


static struct genl_family *genl_family_find_byid(unsigned int id) { struct genl_family *f; list_for_each_entry(f, genl_family_chain(id), family_list) if (f->id == id) return f; return NULL; }

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PersonTokensPropCommitsCommitProp
thomas grafthomas graf39100.00%1100.00%
Total39100.00%1100.00%


static struct genl_family *genl_family_find_byname(char *name) { struct genl_family *f; int i; for (i = 0; i < GENL_FAM_TAB_SIZE; i++) list_for_each_entry(f, genl_family_chain(i), family_list) if (strcmp(f->name, name) == 0) return f; return NULL; }

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PersonTokensPropCommitsCommitProp
thomas grafthomas graf60100.00%1100.00%
Total60100.00%1100.00%


static const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family) { int i; for (i = 0; i < family->n_ops; i++) if (family->ops[i].cmd == cmd) return &family->ops[i]; return NULL; }

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PersonTokensPropCommitsCommitProp
johannes bergjohannes berg3050.00%266.67%
thomas grafthomas graf3050.00%133.33%
Total60100.00%3100.00%

/* Of course we are going to have problems once we hit * 2^16 alive types, but that can only happen by year 2K */
static u16 genl_generate_id(void) { static u16 id_gen_idx = GENL_MIN_ID; int i; for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) { if (id_gen_idx != GENL_ID_VFS_DQUOT && id_gen_idx != GENL_ID_PMCRAID && !genl_family_find_byid(id_gen_idx)) return id_gen_idx; if (++id_gen_idx > GENL_MAX_ID) id_gen_idx = GENL_MIN_ID; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
thomas grafthomas graf3450.75%125.00%
krishna kumarkrishna kumar2537.31%125.00%
johannes bergjohannes berg811.94%250.00%
Total67100.00%4100.00%


static int genl_allocate_reserve_groups(int n_groups, int *first_id) { unsigned long *new_groups; int start = 0; int i; int id; bool fits; do { if (start == 0) id = find_first_zero_bit(mc_groups, mc_groups_longs * BITS_PER_LONG); else id = find_next_zero_bit(mc_groups, mc_groups_longs * BITS_PER_LONG, start); fits = true; for (i = id; i < min_t(int, id + n_groups, mc_groups_longs * BITS_PER_LONG); i++) { if (test_bit(i, mc_groups)) { start = i; fits = false; break; } } if (id + n_groups > mc_groups_longs * BITS_PER_LONG) { unsigned long new_longs = mc_groups_longs + BITS_TO_LONGS(n_groups); size_t nlen = new_longs * sizeof(unsigned long); if (mc_groups == &mc_group_start) { new_groups = kzalloc(nlen, GFP_KERNEL); if (!new_groups) return -ENOMEM; mc_groups = new_groups; *mc_groups = mc_group_start; } else { new_groups = krealloc(mc_groups, nlen, GFP_KERNEL); if (!new_groups) return -ENOMEM; mc_groups = new_groups; for (i = 0; i < BITS_TO_LONGS(n_groups); i++) mc_groups[mc_groups_longs + i] = 0; } mc_groups_longs = new_longs; } } while (!fits); for (i = id; i < id + n_groups; i++) set_bit(i, mc_groups); *first_id = id; return 0; }

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PersonTokensPropCommitsCommitProp
johannes bergjohannes berg25391.01%550.00%
thomas grafthomas graf165.76%110.00%
jamal hadi salimjamal hadi salim41.44%110.00%
matti vaittinenmatti vaittinen20.72%110.00%
brian haleybrian haley20.72%110.00%
david s. millerdavid s. miller10.36%110.00%
Total278100.00%10100.00%

static struct genl_family genl_ctrl;
static int genl_validate_assign_mc_groups(struct genl_family *family) { int first_id; int n_groups = family->n_mcgrps; int err = 0, i; bool groups_allocated = false; if (!n_groups) return 0; for (i = 0; i < n_groups; i++) { const struct genl_multicast_group *grp = &family->mcgrps[i]; if (WARN_ON(grp->name[0] == '\0')) return -EINVAL; if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL)) return -EINVAL; } /* special-case our own group and hacks */ if (family == &genl_ctrl) { first_id = GENL_ID_CTRL; BUG_ON(n_groups != 1); } else if (strcmp(family->name, "NET_DM") == 0) { first_id = 1; BUG_ON(n_groups != 1); } else if (family->id == GENL_ID_VFS_DQUOT) { first_id = GENL_ID_VFS_DQUOT; BUG_ON(n_groups != 1); } else if (family->id == GENL_ID_PMCRAID) { first_id = GENL_ID_PMCRAID; BUG_ON(n_groups != 1); } else { groups_allocated = true; err = genl_allocate_reserve_groups(n_groups, &first_id); if (err) return err; } family->mcgrp_offset = first_id; /* if still initializing, can't and don't need to to realloc bitmaps */ if (!init_net.genl_sock) return 0; if (family->netnsok) { struct net *net; netlink_table_grab(); rcu_read_lock(); for_each_net_rcu(net) { err = __netlink_change_ngroups(net->genl_sock, mc_groups_longs * BITS_PER_LONG); if (err) { /* * No need to roll back, can only fail if * memory allocation fails and then the * number of _possible_ groups has been * increased on some sockets which is ok. */ break; } } rcu_read_unlock(); netlink_table_ungrab(); } else { err = netlink_change_ngroups(init_net.genl_sock, mc_groups_longs * BITS_PER_LONG); } if (groups_allocated && err) { for (i = 0; i < family->n_mcgrps; i++) clear_bit(family->mcgrp_offset + i, mc_groups); } return err; }

Contributors

PersonTokensPropCommitsCommitProp
johannes bergjohannes berg33195.11%654.55%
thomas grafthomas graf113.16%327.27%
jamal hadi salimjamal hadi salim41.15%19.09%
geert uytterhoevengeert uytterhoeven20.57%19.09%
Total348100.00%11100.00%


static void genl_unregister_mc_groups(struct genl_family *family) { struct net *net; int i; netlink_table_grab(); rcu_read_lock(); for_each_net_rcu(net) { for (i = 0; i < family->n_mcgrps; i++) __netlink_clear_multicast_users( net->genl_sock, family->mcgrp_offset + i); } rcu_read_unlock(); netlink_table_ungrab(); for (i = 0; i < family->n_mcgrps; i++) { int grp_id = family->mcgrp_offset + i; if (grp_id != 1) clear_bit(grp_id, mc_groups); genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family, &family->mcgrps[i], grp_id); } }

Contributors

PersonTokensPropCommitsCommitProp
johannes bergjohannes berg11090.91%675.00%
thomas grafthomas graf119.09%225.00%
Total121100.00%8100.00%


static int genl_validate_ops(const struct genl_family *family) { const struct genl_ops *ops = family->ops; unsigned int n_ops = family->n_ops; int i, j; if (WARN_ON(n_ops && !ops)) return -EINVAL; if (!n_ops) return 0; for (i = 0; i < n_ops; i++) { if (ops[i].dumpit == NULL && ops[i].doit == NULL) return -EINVAL; for (j = i + 1; j < n_ops; j++) if (ops[i].cmd == ops[j].cmd) return -EINVAL; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
johannes bergjohannes berg13399.25%583.33%
cheng renquancheng renquan10.75%116.67%
Total134100.00%6100.00%

/** * __genl_register_family - register a generic netlink family * @family: generic netlink family * * Registers the specified family after validating it first. Only one * family may be registered with the same family name or identifier. * The family id may equal GENL_ID_GENERATE causing an unique id to * be automatically generated and assigned. * * The family's ops array must already be assigned, you can use the * genl_register_family_with_ops() helper function. * * Return 0 on success or a negative error code. */
int __genl_register_family(struct genl_family *family) { int err = -EINVAL, i; if (family->id && family->id < GENL_MIN_ID) goto errout; if (family->id > GENL_MAX_ID) goto errout; err = genl_validate_ops(family); if (err) return err; genl_lock_all(); if (genl_family_find_byname(family->name)) { err = -EEXIST; goto errout_locked; } if (family->id == GENL_ID_GENERATE) { u16 newid = genl_generate_id(); if (!newid) { err = -ENOMEM; goto errout_locked; } family->id = newid; } else if (genl_family_find_byid(family->id)) { err = -EEXIST; goto errout_locked; } if (family->maxattr && !family->parallel_ops) { family->attrbuf = kmalloc((family->maxattr+1) * sizeof(struct nlattr *), GFP_KERNEL); if (family->attrbuf == NULL) { err = -ENOMEM; goto errout_locked; } } else family->attrbuf = NULL; err = genl_validate_assign_mc_groups(family); if (err) goto errout_locked; list_add_tail(&family->family_list, genl_family_chain(family->id)); genl_unlock_all(); /* send all events */ genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0); for (i = 0; i < family->n_mcgrps; i++) genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family, &family->mcgrps[i], family->mcgrp_offset + i); return 0; errout_locked: genl_unlock_all(); errout: return err; }

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PersonTokensPropCommitsCommitProp
thomas grafthomas graf19165.41%112.50%
johannes bergjohannes berg7124.32%337.50%
krishna kumarkrishna kumar206.85%112.50%
pravin b shelarpravin b shelar93.08%225.00%
jamal hadi salimjamal hadi salim10.34%112.50%
Total292100.00%8100.00%

EXPORT_SYMBOL(__genl_register_family); /** * genl_unregister_family - unregister generic netlink family * @family: generic netlink family * * Unregisters the specified family. * * Returns 0 on success or a negative error code. */
int genl_unregister_family(struct genl_family *family) { struct genl_family *rc; genl_lock_all(); list_for_each_entry(rc, genl_family_chain(family->id), family_list) { if (family->id != rc->id || strcmp(rc->name, family->name)) continue; genl_unregister_mc_groups(family); list_del(&rc->family_list); family->n_ops = 0; up_write(&cb_lock); wait_event(genl_sk_destructing_waitq, atomic_read(&genl_sk_destructing_cnt) == 0); genl_unlock(); kfree(family->attrbuf); genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0); return 0; } genl_unlock_all(); return -ENOENT; }

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PersonTokensPropCommitsCommitProp
thomas grafthomas graf8369.75%114.29%
johannes bergjohannes berg3226.89%457.14%
pavel emelianovpavel emelianov21.68%114.29%
pravin b shelarpravin b shelar21.68%114.29%
Total119100.00%7100.00%

EXPORT_SYMBOL(genl_unregister_family); /** * 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; }

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PersonTokensPropCommitsCommitProp
denys vlasenkodenys vlasenko10498.11%150.00%
eric w. biedermaneric w. biederman21.89%150.00%
Total106100.00%2100.00%

EXPORT_SYMBOL(genlmsg_put);
static int genl_lock_start(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->start) { genl_lock(); rc = ops->start(cb); genl_unlock(); } return rc; }

Contributors

PersonTokensPropCommitsCommitProp
tom herberttom herbert53100.00%1100.00%
Total53100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
pravin b shelarpravin b shelar4896.00%150.00%
johannes bergjohannes berg24.00%150.00%
Total50100.00%2100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
pravin b shelarpravin b shelar5196.23%150.00%
johannes bergjohannes berg23.77%150.00%
Total53100.00%2100.00%


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 ((ops->flags & GENL_UNS_ADMIN_PERM) && !netlink_ns_capable(skb, net->user_ns, 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, .start = genl_lock_start, .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, .start = ops->start, .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; 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; }

Contributors

PersonTokensPropCommitsCommitProp
thomas grafthomas graf22138.17%211.76%
pravin b shelarpravin b shelar16728.84%317.65%
johannes bergjohannes berg11319.52%317.65%
tycho andersentycho andersen264.49%15.88%
pablo neira ayusopablo neira ayuso254.32%211.76%
tom herberttom herbert122.07%15.88%
wei yongjunwei yongjun81.38%15.88%
eric w. biedermaneric w. biederman50.86%211.76%
darrel goeddeldarrel goeddel10.17%15.88%
eric pariseric paris10.17%15.88%
Total579100.00%17100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
pravin b shelarpravin b shelar7394.81%133.33%
thomas grafthomas graf22.60%133.33%
johannes bergjohannes berg22.60%133.33%
Total77100.00%3100.00%


static void genl_rcv(struct sk_buff *skb) { down_read(&cb_lock); netlink_rcv_skb(skb, &genl_rcv_msg); up_read(&cb_lock); }

Contributors

PersonTokensPropCommitsCommitProp
thomas grafthomas graf1548.39%125.00%
pravin b shelarpravin b shelar1032.26%125.00%
denis v. lunevdenis v. lunev619.35%250.00%
Total31100.00%4100.00%

/************************************************************************** * 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