/* * net/sched/em_meta.c Metadata ematch * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Authors: Thomas Graf <tgraf@suug.ch> * * ========================================================================== * * The metadata ematch compares two meta objects where each object * represents either a meta value stored in the kernel or a static * value provided by userspace. The objects are not provided by * userspace itself but rather a definition providing the information * to build them. Every object is of a certain type which must be * equal to the object it is being compared to. * * The definition of a objects conists of the type (meta type), a * identifier (meta id) and additional type specific information. * The meta id is either TCF_META_TYPE_VALUE for values provided by * userspace or a index to the meta operations table consisting of * function pointers to type specific meta data collectors returning * the value of the requested meta value. * * lvalue rvalue * +-----------+ +-----------+ * | type: INT | | type: INT | * def | id: DEV | | id: VALUE | * | data: | | data: 3 | * +-----------+ +-----------+ * | | * ---> meta_ops[INT][DEV](...) | * | | * ----------- | * V V * +-----------+ +-----------+ * | type: INT | | type: INT | * obj | id: DEV | | id: VALUE | * | data: 2 |<--data got filled out | data: 3 | * +-----------+ +-----------+ * | | * --------------> 2 equals 3 <-------------- * * This is a simplified schema, the complexity varies depending * on the meta type. Obviously, the length of the data must also * be provided for non-numeric types. * * Additionally, type dependent modifiers such as shift operators * or mask may be applied to extend the functionaliy. As of now, * the variable length type supports shifting the byte string to * the right, eating up any number of octets and thus supporting * wildcard interface name comparisons such as "ppp%" matching * ppp0..9. * * NOTE: Certain meta values depend on other subsystems and are * only available if that subsystem is enabled in the kernel. */ #include <linux/slab.h> #include <linux/module.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/string.h> #include <linux/skbuff.h> #include <linux/random.h> #include <linux/if_vlan.h> #include <linux/tc_ematch/tc_em_meta.h> #include <net/dst.h> #include <net/route.h> #include <net/pkt_cls.h> #include <net/sock.h> struct meta_obj { unsigned long value; unsigned int len; }; struct meta_value { struct tcf_meta_val hdr; unsigned long val; unsigned int len; }; struct meta_match { struct meta_value lvalue; struct meta_value rvalue; }; static inline int meta_id(struct meta_value *v) { return TCF_META_ID(v->hdr.kind); } static inline int meta_type(struct meta_value *v) { return TCF_META_TYPE(v->hdr.kind); } #define META_COLLECTOR(FUNC) static void meta_##FUNC(struct sk_buff *skb, \ struct tcf_pkt_info *info, struct meta_value *v, \ struct meta_obj *dst, int *err) /************************************************************************** * System status & misc **************************************************************************/ META_COLLECTOR(int_random) { get_random_bytes(&dst->value, sizeof(dst->value)); } static inline unsigned long fixed_loadavg(int load) { int rnd_load = load + (FIXED_1/200); int rnd_frac = ((rnd_load & (FIXED_1-1)) * 100) >> FSHIFT; return ((rnd_load >> FSHIFT) * 100) + rnd_frac; } META_COLLECTOR(int_loadavg_0) { dst->value = fixed_loadavg(avenrun[0]); } META_COLLECTOR(int_loadavg_1) { dst->value = fixed_loadavg(avenrun[1]); } META_COLLECTOR(int_loadavg_2) { dst->value = fixed_loadavg(avenrun[2]); } /************************************************************************** * Device names & indices **************************************************************************/ static inline int int_dev(struct net_device *dev, struct meta_obj *dst) { if (unlikely(dev == NULL)) return -1; dst->value = dev->ifindex; return 0; } static inline int var_dev(struct net_device *dev, struct meta_obj *dst) { if (unlikely(dev == NULL)) return -1; dst->value = (unsigned long) dev->name; dst->len = strlen(dev->name); return 0; } META_COLLECTOR(int_dev) { *err = int_dev(skb->dev, dst); } META_COLLECTOR(var_dev) { *err = var_dev(skb->dev, dst); } /************************************************************************** * vlan tag **************************************************************************/ META_COLLECTOR(int_vlan_tag) { unsigned short tag; if (skb_vlan_tag_present(skb)) dst->value = skb_vlan_tag_get(skb); else if (!__vlan_get_tag(skb, &tag)) dst->value = tag; else *err = -1; } /************************************************************************** * skb attributes **************************************************************************/ META_COLLECTOR(int_priority) { dst->value = skb->priority; } META_COLLECTOR(int_protocol) { /* Let userspace take care of the byte ordering */ dst->value = tc_skb_protocol(skb); } META_COLLECTOR(int_pkttype) { dst->value = skb->pkt_type; } META_COLLECTOR(int_pktlen) { dst->value = skb->len; } META_COLLECTOR(int_datalen) { dst->value = skb->data_len; } META_COLLECTOR(int_maclen) { dst->value = skb->mac_len; } META_COLLECTOR(int_rxhash) { dst->value = skb_get_hash(skb); } /************************************************************************** * Netfilter **************************************************************************/ META_COLLECTOR(int_mark) { dst->value = skb->mark; } /************************************************************************** * Traffic Control **************************************************************************/ META_COLLECTOR(int_tcindex) { dst->value = skb->tc_index; } /************************************************************************** * Routing **************************************************************************/ META_COLLECTOR(int_rtclassid) { if (unlikely(skb_dst(skb) == NULL)) *err = -1; else #ifdef CONFIG_IP_ROUTE_CLASSID dst->value = skb_dst(skb)->tclassid; #else dst->value = 0; #endif } META_COLLECTOR(int_rtiif) { if (unlikely(skb_rtable(skb) == NULL)) *err = -1; else dst->value = inet_iif(skb); } /************************************************************************** * Socket Attributes **************************************************************************/ #define skip_nonlocal(skb) \ (unlikely(skb->sk == NULL)) META_COLLECTOR(int_sk_family) { if (skip_nonlocal(skb)) { *err = -1; return; } dst->value = skb->sk->sk_family; } META_COLLECTOR(int_sk_state) { if (skip_nonlocal(skb)) { *err = -1; return; } dst->value = skb->sk->sk_state; } META_COLLECTOR(int_sk_reuse) { if (skip_nonlocal(skb)) { *err = -1; return; } dst->value = skb->sk->sk_reuse; } META_COLLECTOR(int_sk_bound_if) { if (skip_nonlocal(skb)) { *err = -1; return; } /* No error if bound_dev_if is 0, legal userspace check */ dst->value = skb->sk->sk_bound_dev_if; } META_COLLECTOR(var_sk_bound_if) { if (skip_nonlocal(skb)) { *err = -1; return; } if (skb->sk->sk_bound_dev_if == 0) { dst->value = (unsigned long) "any"; dst->len = 3; } else { struct net_device *dev; rcu_read_lock(); dev = dev_get_by_index_rcu(sock_net(skb->sk), skb->sk->sk_bound_dev_if); *err = var_dev(dev, dst); rcu_read_unlock(); } } META_COLLECTOR(int_sk_refcnt) { if (skip_nonlocal(skb)) { *err = -1; return; } dst->value = atomic_read(&skb->sk->sk_refcnt); } META_COLLECTOR(int_sk_rcvbuf) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_rcvbuf; } META_COLLECTOR(int_sk_shutdown) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_shutdown; } META_COLLECTOR(int_sk_proto) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_protocol; } META_COLLECTOR(int_sk_type) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_type; } META_COLLECTOR(int_sk_rmem_alloc) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk_rmem_alloc_get(sk); } META_COLLECTOR(int_sk_wmem_alloc) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk_wmem_alloc_get(sk); } META_COLLECTOR(int_sk_omem_alloc) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = atomic_read(&sk->sk_omem_alloc); } META_COLLECTOR(int_sk_rcv_qlen) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_receive_queue.qlen; } META_COLLECTOR(int_sk_snd_qlen) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_write_queue.qlen; } META_COLLECTOR(int_sk_wmem_queued) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_wmem_queued; } META_COLLECTOR(int_sk_fwd_alloc) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_forward_alloc; } META_COLLECTOR(int_sk_sndbuf) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_sndbuf; } META_COLLECTOR(int_sk_alloc) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = (__force int) sk->sk_allocation; } META_COLLECTOR(int_sk_hash) { if (skip_nonlocal(skb)) { *err = -1; return; } dst->value = skb->sk->sk_hash; } META_COLLECTOR(int_sk_lingertime) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_lingertime / HZ; } META_COLLECTOR(int_sk_err_qlen) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_error_queue.qlen; } META_COLLECTOR(int_sk_ack_bl) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_ack_backlog; } META_COLLECTOR(int_sk_max_ack_bl) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_max_ack_backlog; } META_COLLECTOR(int_sk_prio) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_priority; } META_COLLECTOR(int_sk_rcvlowat) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_rcvlowat; } META_COLLECTOR(int_sk_rcvtimeo) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_rcvtimeo / HZ; } META_COLLECTOR(int_sk_sndtimeo) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_sndtimeo / HZ; } META_COLLECTOR(int_sk_sendmsg_off) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_frag.offset; } META_COLLECTOR(int_sk_write_pend) { const struct sock *sk = skb_to_full_sk(skb); if (!sk) { *err = -1; return; } dst->value = sk->sk_write_pending; } /************************************************************************** * Meta value collectors assignment table **************************************************************************/ struct meta_ops { void (*get)(struct sk_buff *, struct tcf_pkt_info *, struct meta_value *, struct meta_obj *, int *); }; #define META_ID(name) TCF_META_ID_##name #define META_FUNC(name) { .get = meta_##name } /* Meta value operations table listing all meta value collectors and * assigns them to a type and meta id. */ static struct meta_ops __meta_ops[TCF_META_TYPE_MAX + 1][TCF_META_ID_MAX + 1] = { [TCF_META_TYPE_VAR] = { [META_ID(DEV)] = META_FUNC(var_dev), [META_ID(SK_BOUND_IF)] = META_FUNC(var_sk_bound_if), }, [TCF_META_TYPE_INT] = { [META_ID(RANDOM)] = META_FUNC(int_random), [META_ID(LOADAVG_0)] = META_FUNC(int_loadavg_0), [META_ID(LOADAVG_1)] = META_FUNC(int_loadavg_1), [META_ID(LOADAVG_2)] = META_FUNC(int_loadavg_2), [META_ID(DEV)] = META_FUNC(int_dev), [META_ID(PRIORITY)] = META_FUNC(int_priority), [META_ID(PROTOCOL)] = META_FUNC(int_protocol), [META_ID(PKTTYPE)] = META_FUNC(int_pkttype), [META_ID(PKTLEN)] = META_FUNC(int_pktlen), [META_ID(DATALEN)] = META_FUNC(int_datalen), [META_ID(MACLEN)] = META_FUNC(int_maclen), [META_ID(NFMARK)] = META_FUNC(int_mark), [META_ID(TCINDEX)] = META_FUNC(int_tcindex), [META_ID(RTCLASSID)] = META_FUNC(int_rtclassid), [META_ID(RTIIF)] = META_FUNC(int_rtiif), [META_ID(SK_FAMILY)] = META_FUNC(int_sk_family), [META_ID(SK_STATE)] = META_FUNC(int_sk_state), [META_ID(SK_REUSE)] = META_FUNC(int_sk_reuse), [META_ID(SK_BOUND_IF)] = META_FUNC(int_sk_bound_if), [META_ID(SK_REFCNT)] = META_FUNC(int_sk_refcnt), [META_ID(SK_RCVBUF)] = META_FUNC(int_sk_rcvbuf), [META_ID(SK_SNDBUF)] = META_FUNC(int_sk_sndbuf), [META_ID(SK_SHUTDOWN)] = META_FUNC(int_sk_shutdown), [META_ID(SK_PROTO)] = META_FUNC(int_sk_proto), [META_ID(SK_TYPE)] = META_FUNC(int_sk_type), [META_ID(SK_RMEM_ALLOC)] = META_FUNC(int_sk_rmem_alloc), [META_ID(SK_WMEM_ALLOC)] = META_FUNC(int_sk_wmem_alloc), [META_ID(SK_OMEM_ALLOC)] = META_FUNC(int_sk_omem_alloc), [META_ID(SK_WMEM_QUEUED)] = META_FUNC(int_sk_wmem_queued), [META_ID(SK_RCV_QLEN)] = META_FUNC(int_sk_rcv_qlen), [META_ID(SK_SND_QLEN)] = META_FUNC(int_sk_snd_qlen), [META_ID(SK_ERR_QLEN)] = META_FUNC(int_sk_err_qlen), [META_ID(SK_FORWARD_ALLOCS)] = META_FUNC(int_sk_fwd_alloc), [META_ID(SK_ALLOCS)] = META_FUNC(int_sk_alloc), [META_ID(SK_HASH)] = META_FUNC(int_sk_hash), [META_ID(SK_LINGERTIME)] = META_FUNC(int_sk_lingertime), [META_ID(SK_ACK_BACKLOG)] = META_FUNC(int_sk_ack_bl), [META_ID(SK_MAX_ACK_BACKLOG)] = META_FUNC(int_sk_max_ack_bl), [META_ID(SK_PRIO)] = META_FUNC(int_sk_prio), [META_ID(SK_RCVLOWAT)] = META_FUNC(int_sk_rcvlowat), [META_ID(SK_RCVTIMEO)] = META_FUNC(int_sk_rcvtimeo), [META_ID(SK_SNDTIMEO)] = META_FUNC(int_sk_sndtimeo), [META_ID(SK_SENDMSG_OFF)] = META_FUNC(int_sk_sendmsg_off), [META_ID(SK_WRITE_PENDING)] = META_FUNC(int_sk_write_pend), [META_ID(VLAN_TAG)] = META_FUNC(int_vlan_tag), [META_ID(RXHASH)] = META_FUNC(int_rxhash), } }; static inline struct meta_ops *meta_ops(struct meta_value *val) { return &__meta_ops[meta_type(val)][meta_id(val)]; } /************************************************************************** * Type specific operations for TCF_META_TYPE_VAR **************************************************************************/ static int meta_var_compare(struct meta_obj *a, struct meta_obj *b) { int r = a->len - b->len; if (r == 0) r = memcmp((void *) a->value, (void *) b->value, a->len); return r; } static int meta_var_change(struct meta_value *dst, struct nlattr *nla) { int len = nla_len(nla); dst->val = (unsigned long)kmemdup(nla_data(nla), len, GFP_KERNEL); if (dst->val == 0UL) return -ENOMEM; dst->len = len; return 0; } static void meta_var_destroy(struct meta_value *v) { kfree((void *) v->val); } static void meta_var_apply_extras(struct meta_value *v, struct meta_obj *dst) { int shift = v->hdr.shift; if (shift && shift < dst->len) dst->len -= shift; } static int meta_var_dump(struct sk_buff *skb, struct meta_value *v, int tlv) { if (v->val && v->len && nla_put(skb, tlv, v->len, (void *) v->val)) goto nla_put_failure; return 0; nla_put_failure: return -1; } /************************************************************************** * Type specific operations for TCF_META_TYPE_INT **************************************************************************/ static int meta_int_compare(struct meta_obj *a, struct meta_obj *b) { /* Let gcc optimize it, the unlikely is not really based on * some numbers but jump free code for mismatches seems * more logical. */ if (unlikely(a->value == b->value)) return 0; else if (a->value < b->value) return -1; else return 1; } static int meta_int_change(struct meta_value *dst, struct nlattr *nla) { if (nla_len(nla) >= sizeof(unsigned long)) { dst->val = *(unsigned long *) nla_data(nla); dst->len = sizeof(unsigned long); } else if (nla_len(nla) == sizeof(u32)) { dst->val = nla_get_u32(nla); dst->len = sizeof(u32); } else return -EINVAL; return 0; } static void meta_int_apply_extras(struct meta_value *v, struct meta_obj *dst) { if (v->hdr.shift) dst->value >>= v->hdr.shift; if (v->val) dst->value &= v->val; } static int meta_int_dump(struct sk_buff *skb, struct meta_value *v, int tlv) { if (v->len == sizeof(unsigned long)) { if (nla_put(skb, tlv, sizeof(unsigned long), &v->val)) goto nla_put_failure; } else if (v->len == sizeof(u32)) { if (nla_put_u32(skb, tlv, v->val)) goto nla_put_failure; } return 0; nla_put_failure: return -1; } /************************************************************************** * Type specific operations table **************************************************************************/ struct meta_type_ops { void (*destroy)(struct meta_value *); int (*compare)(struct meta_obj *, struct meta_obj *); int (*change)(struct meta_value *, struct nlattr *); void (*apply_extras)(struct meta_value *, struct meta_obj *); int (*dump)(struct sk_buff *, struct meta_value *, int); }; static const struct meta_type_ops __meta_type_ops[TCF_META_TYPE_MAX + 1] = { [TCF_META_TYPE_VAR] = { .destroy = meta_var_destroy, .compare = meta_var_compare, .change = meta_var_change, .apply_extras = meta_var_apply_extras, .dump = meta_var_dump }, [TCF_META_TYPE_INT] = { .compare = meta_int_compare, .change = meta_int_change, .apply_extras = meta_int_apply_extras, .dump = meta_int_dump } }; static inline const struct meta_type_ops *meta_type_ops(struct meta_value *v) { return &__meta_type_ops[meta_type(v)]; } /************************************************************************** * Core **************************************************************************/ static int meta_get(struct sk_buff *skb, struct tcf_pkt_info *info, struct meta_value *v, struct meta_obj *dst) { int err = 0; if (meta_id(v) == TCF_META_ID_VALUE) { dst->value = v->val; dst->len = v->len; return 0; } meta_ops(v)->get(skb, info, v, dst, &err); if (err < 0) return err; if (meta_type_ops(v)->apply_extras) meta_type_ops(v)->apply_extras(v, dst); return 0; } static int em_meta_match(struct sk_buff *skb, struct tcf_ematch *m, struct tcf_pkt_info *info) { int r; struct meta_match *meta = (struct meta_match *) m->data; struct meta_obj l_value, r_value; if (meta_get(skb, info, &meta->lvalue, &l_value) < 0 || meta_get(skb, info, &meta->rvalue, &r_value) < 0) return 0; r = meta_type_ops(&meta->lvalue)->compare(&l_value, &r_value); switch (meta->lvalue.hdr.op) { case TCF_EM_OPND_EQ: return !r; case TCF_EM_OPND_LT: return r < 0; case TCF_EM_OPND_GT: return r > 0; } return 0; } static void meta_delete(struct meta_match *meta) { if (meta) { const struct meta_type_ops *ops = meta_type_ops(&meta->lvalue); if (ops && ops->destroy) { ops->destroy(&meta->lvalue); ops->destroy(&meta->rvalue); } } kfree(meta); } static inline int meta_change_data(struct meta_value *dst, struct nlattr *nla) { if (nla) { if (nla_len(nla) == 0) return -EINVAL; return meta_type_ops(dst)->change(dst, nla); } return 0; } static inline int meta_is_supported(struct meta_value *val) { return !meta_id(val) || meta_ops(val)->get; } static const struct nla_policy meta_policy[TCA_EM_META_MAX + 1] = { [TCA_EM_META_HDR] = { .len = sizeof(struct tcf_meta_hdr) }, }; static int em_meta_change(struct net *net, void *data, int len, struct tcf_ematch *m) { int err; struct nlattr *tb[TCA_EM_META_MAX + 1]; struct tcf_meta_hdr *hdr; struct meta_match *meta = NULL; err = nla_parse(tb, TCA_EM_META_MAX, data, len, meta_policy); if (err < 0) goto errout; err = -EINVAL; if (tb[TCA_EM_META_HDR] == NULL) goto errout; hdr = nla_data(tb[TCA_EM_META_HDR]); if (TCF_META_TYPE(hdr->left.kind) != TCF_META_TYPE(hdr->right.kind) || TCF_META_TYPE(hdr->left.kind) > TCF_META_TYPE_MAX || TCF_META_ID(hdr->left.kind) > TCF_META_ID_MAX || TCF_META_ID(hdr->right.kind) > TCF_META_ID_MAX) goto errout; meta = kzalloc(sizeof(*meta), GFP_KERNEL); if (meta == NULL) { err = -ENOMEM; goto errout; } memcpy(&meta->lvalue.hdr, &hdr->left, sizeof(hdr->left)); memcpy(&meta->rvalue.hdr, &hdr->right, sizeof(hdr->right)); if (!meta_is_supported(&meta->lvalue) || !meta_is_supported(&meta->rvalue)) { err = -EOPNOTSUPP; goto errout; } if (meta_change_data(&meta->lvalue, tb[TCA_EM_META_LVALUE]) < 0 || meta_change_data(&meta->rvalue, tb[TCA_EM_META_RVALUE]) < 0) goto errout; m->datalen = sizeof(*meta); m->data = (unsigned long) meta; err = 0; errout: if (err && meta) meta_delete(meta); return err; } static void em_meta_destroy(struct tcf_ematch *m) { if (m) meta_delete((struct meta_match *) m->data); } static int em_meta_dump(struct sk_buff *skb, struct tcf_ematch *em) { struct meta_match *meta = (struct meta_match *) em->data; struct tcf_meta_hdr hdr; const struct meta_type_ops *ops; memset(&hdr, 0, sizeof(hdr)); memcpy(&hdr.left, &meta->lvalue.hdr, sizeof(hdr.left)); memcpy(&hdr.right, &meta->rvalue.hdr, sizeof(hdr.right)); if (nla_put(skb, TCA_EM_META_HDR, sizeof(hdr), &hdr)) goto nla_put_failure; ops = meta_type_ops(&meta->lvalue); if (ops->dump(skb, &meta->lvalue, TCA_EM_META_LVALUE) < 0 || ops->dump(skb, &meta->rvalue, TCA_EM_META_RVALUE) < 0) goto nla_put_failure; return 0; nla_put_failure: return -1; } static struct tcf_ematch_ops em_meta_ops = { .kind = TCF_EM_META, .change = em_meta_change, .match = em_meta_match, .destroy = em_meta_destroy, .dump = em_meta_dump, .owner = THIS_MODULE, .link = LIST_HEAD_INIT(em_meta_ops.link) }; static int __init init_em_meta(void) { return tcf_em_register(&em_meta_ops); } static void __exit exit_em_meta(void) { tcf_em_unregister(&em_meta_ops); } MODULE_LICENSE("GPL"); module_init(init_em_meta); module_exit(exit_em_meta); MODULE_ALIAS_TCF_EMATCH(TCF_EM_META);