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linux/net/core/flow_dissector.c
David S. Miller eb70db8756 packet: Use symmetric hash for PACKET_FANOUT_HASH.
People who use PACKET_FANOUT_HASH want a symmetric hash, meaning that
they want packets going in both directions on a flow to hash to the
same bucket.

The core kernel SKB hash became non-symmetric when the ipv6 flow label
and other entities were incorporated into the standard flow hash order
to increase entropy.

But there are no users of PACKET_FANOUT_HASH who want an assymetric
hash, they all want a symmetric one.

Therefore, use the flow dissector to compute a flat symmetric hash
over only the protocol, addresses and ports.  This hash does not get
installed into and override the normal skb hash, so this change has
no effect whatsoever on the rest of the stack.

Reported-by: Eric Leblond <eric@regit.org>
Tested-by: Eric Leblond <eric@regit.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-01 16:07:50 -04:00

942 lines
24 KiB
C

#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/export.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/if_vlan.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <linux/igmp.h>
#include <linux/icmp.h>
#include <linux/sctp.h>
#include <linux/dccp.h>
#include <linux/if_tunnel.h>
#include <linux/if_pppox.h>
#include <linux/ppp_defs.h>
#include <linux/stddef.h>
#include <linux/if_ether.h>
#include <linux/mpls.h>
#include <net/flow_dissector.h>
#include <scsi/fc/fc_fcoe.h>
static void dissector_set_key(struct flow_dissector *flow_dissector,
enum flow_dissector_key_id key_id)
{
flow_dissector->used_keys |= (1 << key_id);
}
void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
const struct flow_dissector_key *key,
unsigned int key_count)
{
unsigned int i;
memset(flow_dissector, 0, sizeof(*flow_dissector));
for (i = 0; i < key_count; i++, key++) {
/* User should make sure that every key target offset is withing
* boundaries of unsigned short.
*/
BUG_ON(key->offset > USHRT_MAX);
BUG_ON(dissector_uses_key(flow_dissector,
key->key_id));
dissector_set_key(flow_dissector, key->key_id);
flow_dissector->offset[key->key_id] = key->offset;
}
/* Ensure that the dissector always includes control and basic key.
* That way we are able to avoid handling lack of these in fast path.
*/
BUG_ON(!dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_CONTROL));
BUG_ON(!dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_BASIC));
}
EXPORT_SYMBOL(skb_flow_dissector_init);
/**
* __skb_flow_get_ports - extract the upper layer ports and return them
* @skb: sk_buff to extract the ports from
* @thoff: transport header offset
* @ip_proto: protocol for which to get port offset
* @data: raw buffer pointer to the packet, if NULL use skb->data
* @hlen: packet header length, if @data is NULL use skb_headlen(skb)
*
* The function will try to retrieve the ports at offset thoff + poff where poff
* is the protocol port offset returned from proto_ports_offset
*/
__be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
void *data, int hlen)
{
int poff = proto_ports_offset(ip_proto);
if (!data) {
data = skb->data;
hlen = skb_headlen(skb);
}
if (poff >= 0) {
__be32 *ports, _ports;
ports = __skb_header_pointer(skb, thoff + poff,
sizeof(_ports), data, hlen, &_ports);
if (ports)
return *ports;
}
return 0;
}
EXPORT_SYMBOL(__skb_flow_get_ports);
/**
* __skb_flow_dissect - extract the flow_keys struct and return it
* @skb: sk_buff to extract the flow from, can be NULL if the rest are specified
* @flow_dissector: list of keys to dissect
* @target_container: target structure to put dissected values into
* @data: raw buffer pointer to the packet, if NULL use skb->data
* @proto: protocol for which to get the flow, if @data is NULL use skb->protocol
* @nhoff: network header offset, if @data is NULL use skb_network_offset(skb)
* @hlen: packet header length, if @data is NULL use skb_headlen(skb)
*
* The function will try to retrieve individual keys into target specified
* by flow_dissector from either the skbuff or a raw buffer specified by the
* rest parameters.
*
* Caller must take care of zeroing target container memory.
*/
bool __skb_flow_dissect(const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
void *target_container,
void *data, __be16 proto, int nhoff, int hlen,
unsigned int flags)
{
struct flow_dissector_key_control *key_control;
struct flow_dissector_key_basic *key_basic;
struct flow_dissector_key_addrs *key_addrs;
struct flow_dissector_key_ports *key_ports;
struct flow_dissector_key_tags *key_tags;
struct flow_dissector_key_keyid *key_keyid;
u8 ip_proto = 0;
bool ret = false;
if (!data) {
data = skb->data;
proto = skb->protocol;
nhoff = skb_network_offset(skb);
hlen = skb_headlen(skb);
}
/* It is ensured by skb_flow_dissector_init() that control key will
* be always present.
*/
key_control = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_CONTROL,
target_container);
/* It is ensured by skb_flow_dissector_init() that basic key will
* be always present.
*/
key_basic = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_BASIC,
target_container);
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
struct ethhdr *eth = eth_hdr(skb);
struct flow_dissector_key_eth_addrs *key_eth_addrs;
key_eth_addrs = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_ETH_ADDRS,
target_container);
memcpy(key_eth_addrs, &eth->h_dest, sizeof(*key_eth_addrs));
}
again:
switch (proto) {
case htons(ETH_P_IP): {
const struct iphdr *iph;
struct iphdr _iph;
ip:
iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
if (!iph || iph->ihl < 5)
goto out_bad;
nhoff += iph->ihl * 4;
ip_proto = iph->protocol;
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_IPV4_ADDRS)) {
key_addrs = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_IPV4_ADDRS,
target_container);
memcpy(&key_addrs->v4addrs, &iph->saddr,
sizeof(key_addrs->v4addrs));
key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
}
if (ip_is_fragment(iph)) {
key_control->flags |= FLOW_DIS_IS_FRAGMENT;
if (iph->frag_off & htons(IP_OFFSET)) {
goto out_good;
} else {
key_control->flags |= FLOW_DIS_FIRST_FRAG;
if (!(flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG))
goto out_good;
}
}
if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
goto out_good;
break;
}
case htons(ETH_P_IPV6): {
const struct ipv6hdr *iph;
struct ipv6hdr _iph;
ipv6:
iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
if (!iph)
goto out_bad;
ip_proto = iph->nexthdr;
nhoff += sizeof(struct ipv6hdr);
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
key_addrs = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_IPV6_ADDRS,
target_container);
memcpy(&key_addrs->v6addrs, &iph->saddr,
sizeof(key_addrs->v6addrs));
key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
}
if ((dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_FLOW_LABEL) ||
(flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)) &&
ip6_flowlabel(iph)) {
__be32 flow_label = ip6_flowlabel(iph);
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_FLOW_LABEL)) {
key_tags = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_FLOW_LABEL,
target_container);
key_tags->flow_label = ntohl(flow_label);
}
if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)
goto out_good;
}
if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
goto out_good;
break;
}
case htons(ETH_P_8021AD):
case htons(ETH_P_8021Q): {
const struct vlan_hdr *vlan;
struct vlan_hdr _vlan;
vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan), data, hlen, &_vlan);
if (!vlan)
goto out_bad;
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_VLANID)) {
key_tags = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_VLANID,
target_container);
key_tags->vlan_id = skb_vlan_tag_get_id(skb);
}
proto = vlan->h_vlan_encapsulated_proto;
nhoff += sizeof(*vlan);
goto again;
}
case htons(ETH_P_PPP_SES): {
struct {
struct pppoe_hdr hdr;
__be16 proto;
} *hdr, _hdr;
hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
if (!hdr)
goto out_bad;
proto = hdr->proto;
nhoff += PPPOE_SES_HLEN;
switch (proto) {
case htons(PPP_IP):
goto ip;
case htons(PPP_IPV6):
goto ipv6;
default:
goto out_bad;
}
}
case htons(ETH_P_TIPC): {
struct {
__be32 pre[3];
__be32 srcnode;
} *hdr, _hdr;
hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
if (!hdr)
goto out_bad;
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_TIPC_ADDRS)) {
key_addrs = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_TIPC_ADDRS,
target_container);
key_addrs->tipcaddrs.srcnode = hdr->srcnode;
key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC_ADDRS;
}
goto out_good;
}
case htons(ETH_P_MPLS_UC):
case htons(ETH_P_MPLS_MC): {
struct mpls_label *hdr, _hdr[2];
mpls:
hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
hlen, &_hdr);
if (!hdr)
goto out_bad;
if ((ntohl(hdr[0].entry) & MPLS_LS_LABEL_MASK) >>
MPLS_LS_LABEL_SHIFT == MPLS_LABEL_ENTROPY) {
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_MPLS_ENTROPY)) {
key_keyid = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_MPLS_ENTROPY,
target_container);
key_keyid->keyid = hdr[1].entry &
htonl(MPLS_LS_LABEL_MASK);
}
goto out_good;
}
goto out_good;
}
case htons(ETH_P_FCOE):
if ((hlen - nhoff) < FCOE_HEADER_LEN)
goto out_bad;
nhoff += FCOE_HEADER_LEN;
goto out_good;
default:
goto out_bad;
}
ip_proto_again:
switch (ip_proto) {
case IPPROTO_GRE: {
struct gre_hdr {
__be16 flags;
__be16 proto;
} *hdr, _hdr;
hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
if (!hdr)
goto out_bad;
/*
* Only look inside GRE if version zero and no
* routing
*/
if (hdr->flags & (GRE_VERSION | GRE_ROUTING))
break;
proto = hdr->proto;
nhoff += 4;
if (hdr->flags & GRE_CSUM)
nhoff += 4;
if (hdr->flags & GRE_KEY) {
const __be32 *keyid;
__be32 _keyid;
keyid = __skb_header_pointer(skb, nhoff, sizeof(_keyid),
data, hlen, &_keyid);
if (!keyid)
goto out_bad;
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_GRE_KEYID)) {
key_keyid = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_GRE_KEYID,
target_container);
key_keyid->keyid = *keyid;
}
nhoff += 4;
}
if (hdr->flags & GRE_SEQ)
nhoff += 4;
if (proto == htons(ETH_P_TEB)) {
const struct ethhdr *eth;
struct ethhdr _eth;
eth = __skb_header_pointer(skb, nhoff,
sizeof(_eth),
data, hlen, &_eth);
if (!eth)
goto out_bad;
proto = eth->h_proto;
nhoff += sizeof(*eth);
/* Cap headers that we access via pointers at the
* end of the Ethernet header as our maximum alignment
* at that point is only 2 bytes.
*/
if (NET_IP_ALIGN)
hlen = nhoff;
}
key_control->flags |= FLOW_DIS_ENCAPSULATION;
if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
goto out_good;
goto again;
}
case NEXTHDR_HOP:
case NEXTHDR_ROUTING:
case NEXTHDR_DEST: {
u8 _opthdr[2], *opthdr;
if (proto != htons(ETH_P_IPV6))
break;
opthdr = __skb_header_pointer(skb, nhoff, sizeof(_opthdr),
data, hlen, &_opthdr);
if (!opthdr)
goto out_bad;
ip_proto = opthdr[0];
nhoff += (opthdr[1] + 1) << 3;
goto ip_proto_again;
}
case NEXTHDR_FRAGMENT: {
struct frag_hdr _fh, *fh;
if (proto != htons(ETH_P_IPV6))
break;
fh = __skb_header_pointer(skb, nhoff, sizeof(_fh),
data, hlen, &_fh);
if (!fh)
goto out_bad;
key_control->flags |= FLOW_DIS_IS_FRAGMENT;
nhoff += sizeof(_fh);
ip_proto = fh->nexthdr;
if (!(fh->frag_off & htons(IP6_OFFSET))) {
key_control->flags |= FLOW_DIS_FIRST_FRAG;
if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG)
goto ip_proto_again;
}
goto out_good;
}
case IPPROTO_IPIP:
proto = htons(ETH_P_IP);
key_control->flags |= FLOW_DIS_ENCAPSULATION;
if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
goto out_good;
goto ip;
case IPPROTO_IPV6:
proto = htons(ETH_P_IPV6);
key_control->flags |= FLOW_DIS_ENCAPSULATION;
if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
goto out_good;
goto ipv6;
case IPPROTO_MPLS:
proto = htons(ETH_P_MPLS_UC);
goto mpls;
default:
break;
}
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_PORTS)) {
key_ports = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_PORTS,
target_container);
key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto,
data, hlen);
}
out_good:
ret = true;
out_bad:
key_basic->n_proto = proto;
key_basic->ip_proto = ip_proto;
key_control->thoff = (u16)nhoff;
return ret;
}
EXPORT_SYMBOL(__skb_flow_dissect);
static u32 hashrnd __read_mostly;
static __always_inline void __flow_hash_secret_init(void)
{
net_get_random_once(&hashrnd, sizeof(hashrnd));
}
static __always_inline u32 __flow_hash_words(const u32 *words, u32 length,
u32 keyval)
{
return jhash2(words, length, keyval);
}
static inline const u32 *flow_keys_hash_start(const struct flow_keys *flow)
{
const void *p = flow;
BUILD_BUG_ON(FLOW_KEYS_HASH_OFFSET % sizeof(u32));
return (const u32 *)(p + FLOW_KEYS_HASH_OFFSET);
}
static inline size_t flow_keys_hash_length(const struct flow_keys *flow)
{
size_t diff = FLOW_KEYS_HASH_OFFSET + sizeof(flow->addrs);
BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32));
BUILD_BUG_ON(offsetof(typeof(*flow), addrs) !=
sizeof(*flow) - sizeof(flow->addrs));
switch (flow->control.addr_type) {
case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
diff -= sizeof(flow->addrs.v4addrs);
break;
case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
diff -= sizeof(flow->addrs.v6addrs);
break;
case FLOW_DISSECTOR_KEY_TIPC_ADDRS:
diff -= sizeof(flow->addrs.tipcaddrs);
break;
}
return (sizeof(*flow) - diff) / sizeof(u32);
}
__be32 flow_get_u32_src(const struct flow_keys *flow)
{
switch (flow->control.addr_type) {
case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
return flow->addrs.v4addrs.src;
case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
return (__force __be32)ipv6_addr_hash(
&flow->addrs.v6addrs.src);
case FLOW_DISSECTOR_KEY_TIPC_ADDRS:
return flow->addrs.tipcaddrs.srcnode;
default:
return 0;
}
}
EXPORT_SYMBOL(flow_get_u32_src);
__be32 flow_get_u32_dst(const struct flow_keys *flow)
{
switch (flow->control.addr_type) {
case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
return flow->addrs.v4addrs.dst;
case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
return (__force __be32)ipv6_addr_hash(
&flow->addrs.v6addrs.dst);
default:
return 0;
}
}
EXPORT_SYMBOL(flow_get_u32_dst);
static inline void __flow_hash_consistentify(struct flow_keys *keys)
{
int addr_diff, i;
switch (keys->control.addr_type) {
case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
addr_diff = (__force u32)keys->addrs.v4addrs.dst -
(__force u32)keys->addrs.v4addrs.src;
if ((addr_diff < 0) ||
(addr_diff == 0 &&
((__force u16)keys->ports.dst <
(__force u16)keys->ports.src))) {
swap(keys->addrs.v4addrs.src, keys->addrs.v4addrs.dst);
swap(keys->ports.src, keys->ports.dst);
}
break;
case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
addr_diff = memcmp(&keys->addrs.v6addrs.dst,
&keys->addrs.v6addrs.src,
sizeof(keys->addrs.v6addrs.dst));
if ((addr_diff < 0) ||
(addr_diff == 0 &&
((__force u16)keys->ports.dst <
(__force u16)keys->ports.src))) {
for (i = 0; i < 4; i++)
swap(keys->addrs.v6addrs.src.s6_addr32[i],
keys->addrs.v6addrs.dst.s6_addr32[i]);
swap(keys->ports.src, keys->ports.dst);
}
break;
}
}
static inline u32 __flow_hash_from_keys(struct flow_keys *keys, u32 keyval)
{
u32 hash;
__flow_hash_consistentify(keys);
hash = __flow_hash_words(flow_keys_hash_start(keys),
flow_keys_hash_length(keys), keyval);
if (!hash)
hash = 1;
return hash;
}
u32 flow_hash_from_keys(struct flow_keys *keys)
{
__flow_hash_secret_init();
return __flow_hash_from_keys(keys, hashrnd);
}
EXPORT_SYMBOL(flow_hash_from_keys);
static inline u32 ___skb_get_hash(const struct sk_buff *skb,
struct flow_keys *keys, u32 keyval)
{
skb_flow_dissect_flow_keys(skb, keys,
FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
return __flow_hash_from_keys(keys, keyval);
}
struct _flow_keys_digest_data {
__be16 n_proto;
u8 ip_proto;
u8 padding;
__be32 ports;
__be32 src;
__be32 dst;
};
void make_flow_keys_digest(struct flow_keys_digest *digest,
const struct flow_keys *flow)
{
struct _flow_keys_digest_data *data =
(struct _flow_keys_digest_data *)digest;
BUILD_BUG_ON(sizeof(*data) > sizeof(*digest));
memset(digest, 0, sizeof(*digest));
data->n_proto = flow->basic.n_proto;
data->ip_proto = flow->basic.ip_proto;
data->ports = flow->ports.ports;
data->src = flow->addrs.v4addrs.src;
data->dst = flow->addrs.v4addrs.dst;
}
EXPORT_SYMBOL(make_flow_keys_digest);
static struct flow_dissector flow_keys_dissector_symmetric __read_mostly;
u32 __skb_get_hash_symmetric(struct sk_buff *skb)
{
struct flow_keys keys;
__flow_hash_secret_init();
memset(&keys, 0, sizeof(keys));
__skb_flow_dissect(skb, &flow_keys_dissector_symmetric, &keys,
NULL, 0, 0, 0,
FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
return __flow_hash_from_keys(&keys, hashrnd);
}
EXPORT_SYMBOL_GPL(__skb_get_hash_symmetric);
/**
* __skb_get_hash: calculate a flow hash
* @skb: sk_buff to calculate flow hash from
*
* This function calculates a flow hash based on src/dst addresses
* and src/dst port numbers. Sets hash in skb to non-zero hash value
* on success, zero indicates no valid hash. Also, sets l4_hash in skb
* if hash is a canonical 4-tuple hash over transport ports.
*/
void __skb_get_hash(struct sk_buff *skb)
{
struct flow_keys keys;
__flow_hash_secret_init();
__skb_set_sw_hash(skb, ___skb_get_hash(skb, &keys, hashrnd),
flow_keys_have_l4(&keys));
}
EXPORT_SYMBOL(__skb_get_hash);
__u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb)
{
struct flow_keys keys;
return ___skb_get_hash(skb, &keys, perturb);
}
EXPORT_SYMBOL(skb_get_hash_perturb);
__u32 __skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6)
{
struct flow_keys keys;
memset(&keys, 0, sizeof(keys));
memcpy(&keys.addrs.v6addrs.src, &fl6->saddr,
sizeof(keys.addrs.v6addrs.src));
memcpy(&keys.addrs.v6addrs.dst, &fl6->daddr,
sizeof(keys.addrs.v6addrs.dst));
keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
keys.ports.src = fl6->fl6_sport;
keys.ports.dst = fl6->fl6_dport;
keys.keyid.keyid = fl6->fl6_gre_key;
keys.tags.flow_label = (__force u32)fl6->flowlabel;
keys.basic.ip_proto = fl6->flowi6_proto;
__skb_set_sw_hash(skb, flow_hash_from_keys(&keys),
flow_keys_have_l4(&keys));
return skb->hash;
}
EXPORT_SYMBOL(__skb_get_hash_flowi6);
__u32 __skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl4)
{
struct flow_keys keys;
memset(&keys, 0, sizeof(keys));
keys.addrs.v4addrs.src = fl4->saddr;
keys.addrs.v4addrs.dst = fl4->daddr;
keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
keys.ports.src = fl4->fl4_sport;
keys.ports.dst = fl4->fl4_dport;
keys.keyid.keyid = fl4->fl4_gre_key;
keys.basic.ip_proto = fl4->flowi4_proto;
__skb_set_sw_hash(skb, flow_hash_from_keys(&keys),
flow_keys_have_l4(&keys));
return skb->hash;
}
EXPORT_SYMBOL(__skb_get_hash_flowi4);
u32 __skb_get_poff(const struct sk_buff *skb, void *data,
const struct flow_keys *keys, int hlen)
{
u32 poff = keys->control.thoff;
/* skip L4 headers for fragments after the first */
if ((keys->control.flags & FLOW_DIS_IS_FRAGMENT) &&
!(keys->control.flags & FLOW_DIS_FIRST_FRAG))
return poff;
switch (keys->basic.ip_proto) {
case IPPROTO_TCP: {
/* access doff as u8 to avoid unaligned access */
const u8 *doff;
u8 _doff;
doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff),
data, hlen, &_doff);
if (!doff)
return poff;
poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2);
break;
}
case IPPROTO_UDP:
case IPPROTO_UDPLITE:
poff += sizeof(struct udphdr);
break;
/* For the rest, we do not really care about header
* extensions at this point for now.
*/
case IPPROTO_ICMP:
poff += sizeof(struct icmphdr);
break;
case IPPROTO_ICMPV6:
poff += sizeof(struct icmp6hdr);
break;
case IPPROTO_IGMP:
poff += sizeof(struct igmphdr);
break;
case IPPROTO_DCCP:
poff += sizeof(struct dccp_hdr);
break;
case IPPROTO_SCTP:
poff += sizeof(struct sctphdr);
break;
}
return poff;
}
/**
* skb_get_poff - get the offset to the payload
* @skb: sk_buff to get the payload offset from
*
* The function will get the offset to the payload as far as it could
* be dissected. The main user is currently BPF, so that we can dynamically
* truncate packets without needing to push actual payload to the user
* space and can analyze headers only, instead.
*/
u32 skb_get_poff(const struct sk_buff *skb)
{
struct flow_keys keys;
if (!skb_flow_dissect_flow_keys(skb, &keys, 0))
return 0;
return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb));
}
__u32 __get_hash_from_flowi6(const struct flowi6 *fl6, struct flow_keys *keys)
{
memset(keys, 0, sizeof(*keys));
memcpy(&keys->addrs.v6addrs.src, &fl6->saddr,
sizeof(keys->addrs.v6addrs.src));
memcpy(&keys->addrs.v6addrs.dst, &fl6->daddr,
sizeof(keys->addrs.v6addrs.dst));
keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
keys->ports.src = fl6->fl6_sport;
keys->ports.dst = fl6->fl6_dport;
keys->keyid.keyid = fl6->fl6_gre_key;
keys->tags.flow_label = (__force u32)fl6->flowlabel;
keys->basic.ip_proto = fl6->flowi6_proto;
return flow_hash_from_keys(keys);
}
EXPORT_SYMBOL(__get_hash_from_flowi6);
__u32 __get_hash_from_flowi4(const struct flowi4 *fl4, struct flow_keys *keys)
{
memset(keys, 0, sizeof(*keys));
keys->addrs.v4addrs.src = fl4->saddr;
keys->addrs.v4addrs.dst = fl4->daddr;
keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
keys->ports.src = fl4->fl4_sport;
keys->ports.dst = fl4->fl4_dport;
keys->keyid.keyid = fl4->fl4_gre_key;
keys->basic.ip_proto = fl4->flowi4_proto;
return flow_hash_from_keys(keys);
}
EXPORT_SYMBOL(__get_hash_from_flowi4);
static const struct flow_dissector_key flow_keys_dissector_keys[] = {
{
.key_id = FLOW_DISSECTOR_KEY_CONTROL,
.offset = offsetof(struct flow_keys, control),
},
{
.key_id = FLOW_DISSECTOR_KEY_BASIC,
.offset = offsetof(struct flow_keys, basic),
},
{
.key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
.offset = offsetof(struct flow_keys, addrs.v4addrs),
},
{
.key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS,
.offset = offsetof(struct flow_keys, addrs.v6addrs),
},
{
.key_id = FLOW_DISSECTOR_KEY_TIPC_ADDRS,
.offset = offsetof(struct flow_keys, addrs.tipcaddrs),
},
{
.key_id = FLOW_DISSECTOR_KEY_PORTS,
.offset = offsetof(struct flow_keys, ports),
},
{
.key_id = FLOW_DISSECTOR_KEY_VLANID,
.offset = offsetof(struct flow_keys, tags),
},
{
.key_id = FLOW_DISSECTOR_KEY_FLOW_LABEL,
.offset = offsetof(struct flow_keys, tags),
},
{
.key_id = FLOW_DISSECTOR_KEY_GRE_KEYID,
.offset = offsetof(struct flow_keys, keyid),
},
};
static const struct flow_dissector_key flow_keys_dissector_symmetric_keys[] = {
{
.key_id = FLOW_DISSECTOR_KEY_CONTROL,
.offset = offsetof(struct flow_keys, control),
},
{
.key_id = FLOW_DISSECTOR_KEY_BASIC,
.offset = offsetof(struct flow_keys, basic),
},
{
.key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
.offset = offsetof(struct flow_keys, addrs.v4addrs),
},
{
.key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS,
.offset = offsetof(struct flow_keys, addrs.v6addrs),
},
{
.key_id = FLOW_DISSECTOR_KEY_PORTS,
.offset = offsetof(struct flow_keys, ports),
},
};
static const struct flow_dissector_key flow_keys_buf_dissector_keys[] = {
{
.key_id = FLOW_DISSECTOR_KEY_CONTROL,
.offset = offsetof(struct flow_keys, control),
},
{
.key_id = FLOW_DISSECTOR_KEY_BASIC,
.offset = offsetof(struct flow_keys, basic),
},
};
struct flow_dissector flow_keys_dissector __read_mostly;
EXPORT_SYMBOL(flow_keys_dissector);
struct flow_dissector flow_keys_buf_dissector __read_mostly;
static int __init init_default_flow_dissectors(void)
{
skb_flow_dissector_init(&flow_keys_dissector,
flow_keys_dissector_keys,
ARRAY_SIZE(flow_keys_dissector_keys));
skb_flow_dissector_init(&flow_keys_dissector_symmetric,
flow_keys_dissector_symmetric_keys,
ARRAY_SIZE(flow_keys_dissector_symmetric_keys));
skb_flow_dissector_init(&flow_keys_buf_dissector,
flow_keys_buf_dissector_keys,
ARRAY_SIZE(flow_keys_buf_dissector_keys));
return 0;
}
late_initcall_sync(init_default_flow_dissectors);