cregit-Linux how code gets into the kernel

Release 4.8 net/sched/em_meta.c

Directory: net/sched
/*
 * 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); }

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static inline int meta_type(struct meta_value *v) { return TCF_META_TYPE(v->hdr.kind); }

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#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; }

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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; }

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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; }

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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; tag = skb_vlan_tag_get(skb); if (!tag && __vlan_get_tag(skb, &tag)) *err = -1; else dst->value = tag; } /************************************************************************** * 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)]; }

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/************************************************************************** * 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; }

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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; }

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static void meta_var_destroy(struct meta_value *v) { kfree((void *) v->val); }

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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; }

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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; }

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/************************************************************************** * 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;