blob: 7a0b391114a51a0427fa27a52af010e19e1002a5 [file] [log] [blame]
#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 <net/flow_dissector.h>
#include <scsi/fc/fc_fcoe.h>
static bool skb_flow_dissector_uses_key(struct flow_dissector *flow_dissector,
enum flow_dissector_key_id key_id)
{
return flow_dissector->used_keys & (1 << key_id);
}
static void skb_flow_dissector_set_key(struct flow_dissector *flow_dissector,
enum flow_dissector_key_id key_id)
{
flow_dissector->used_keys |= (1 << key_id);
}
static void *skb_flow_dissector_target(struct flow_dissector *flow_dissector,
enum flow_dissector_key_id key_id,
void *target_container)
{
return ((char *) target_container) + flow_dissector->offset[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(skb_flow_dissector_uses_key(flow_dissector,
key->key_id));
skb_flow_dissector_set_key(flow_dissector, key->key_id);
flow_dissector->offset[key->key_id] = key->offset;
}
/* Ensure that the dissector always includes basic key. That way
* we are able to avoid handling lack of it in fast path.
*/
BUG_ON(!skb_flow_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)
{
struct flow_dissector_key_basic *key_basic;
struct flow_dissector_key_addrs *key_addrs;
struct flow_dissector_key_ports *key_ports;
u8 ip_proto;
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 basic key will
* be always present.
*/
key_basic = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_BASIC,
target_container);
if (skb_flow_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)
return false;
nhoff += iph->ihl * 4;
ip_proto = iph->protocol;
if (ip_is_fragment(iph))
ip_proto = 0;
if (!skb_flow_dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_IPV4_ADDRS))
break;
key_addrs = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_IPV4_ADDRS,
target_container);
memcpy(key_addrs, &iph->saddr, sizeof(*key_addrs));
break;
}
case htons(ETH_P_IPV6): {
const struct ipv6hdr *iph;
struct ipv6hdr _iph;
__be32 flow_label;
ipv6:
iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
if (!iph)
return false;
ip_proto = iph->nexthdr;
nhoff += sizeof(struct ipv6hdr);
if (skb_flow_dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS)) {
key_addrs = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS,
target_container);
key_addrs->src = (__force __be32)ipv6_addr_hash(&iph->saddr);
key_addrs->dst = (__force __be32)ipv6_addr_hash(&iph->daddr);
goto flow_label;
}
if (skb_flow_dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
struct flow_dissector_key_ipv6_addrs *key_ipv6_addrs;
key_ipv6_addrs = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_IPV6_ADDRS,
target_container);
memcpy(key_ipv6_addrs, &iph->saddr, sizeof(*key_ipv6_addrs));
goto flow_label;
}
break;
flow_label:
flow_label = ip6_flowlabel(iph);
if (flow_label) {
/* Awesome, IPv6 packet has a flow label so we can
* use that to represent the ports without any
* further dissection.
*/
key_basic->n_proto = proto;
key_basic->ip_proto = ip_proto;
key_basic->thoff = (u16)nhoff;
if (!skb_flow_dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_PORTS))
break;
key_ports = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_PORTS,
target_container);
key_ports->ports = flow_label;
return true;
}
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)
return false;
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)
return false;
proto = hdr->proto;
nhoff += PPPOE_SES_HLEN;
switch (proto) {
case htons(PPP_IP):
goto ip;
case htons(PPP_IPV6):
goto ipv6;
default:
return false;
}
}
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)
return false;
key_basic->n_proto = proto;
key_basic->thoff = (u16)nhoff;
if (skb_flow_dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS)) {
return true;
key_addrs = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS,
target_container);
key_addrs->src = hdr->srcnode;
key_addrs->dst = 0;
}
return true;
}
case htons(ETH_P_FCOE):
key_basic->thoff = (u16)(nhoff + FCOE_HEADER_LEN);
/* fall through */
default:
return false;
}
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)
return false;
/*
* Only look inside GRE if version zero and no
* routing
*/
if (!(hdr->flags & (GRE_VERSION|GRE_ROUTING))) {
proto = hdr->proto;
nhoff += 4;
if (hdr->flags & GRE_CSUM)
nhoff += 4;
if (hdr->flags & GRE_KEY)
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)
return false;
proto = eth->h_proto;
nhoff += sizeof(*eth);
}
goto again;
}
break;
}
case IPPROTO_IPIP:
proto = htons(ETH_P_IP);
goto ip;
case IPPROTO_IPV6:
proto = htons(ETH_P_IPV6);
goto ipv6;
default:
break;
}
/* 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);
key_basic->n_proto = proto;
key_basic->ip_proto = ip_proto;
key_basic->thoff = (u16) nhoff;
if (skb_flow_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);
}
return true;
}
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_3words(u32 a, u32 b, u32 c, u32 keyval)
{
return jhash_3words(a, b, c, keyval);
}
static inline u32 __flow_hash_from_keys(struct flow_keys *keys, u32 keyval)
{
u32 hash;
/* get a consistent hash (same value on both flow directions) */
if (((__force u32)keys->addrs.dst < (__force u32)keys->addrs.src) ||
(((__force u32)keys->addrs.dst == (__force u32)keys->addrs.src) &&
((__force u16)keys->ports.port16[1] < (__force u16)keys->ports.port16[0]))) {
swap(keys->addrs.dst, keys->addrs.src);
swap(keys->ports.port16[0], keys->ports.port16[1]);
}
hash = __flow_hash_3words((__force u32)keys->addrs.dst,
(__force u32)keys->addrs.src,
(__force u32)keys->ports.ports,
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)
{
if (!skb_flow_dissect_flow_keys(skb, keys))
return 0;
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.src;
data->dst = flow->addrs.dst;
}
EXPORT_SYMBOL(make_flow_keys_digest);
/**
* __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;
u32 hash;
__flow_hash_secret_init();
hash = ___skb_get_hash(skb, &keys, hashrnd);
if (!hash)
return;
if (keys.ports.ports)
skb->l4_hash = 1;
skb->sw_hash = 1;
skb->hash = hash;
}
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_poff(const struct sk_buff *skb, void *data,
const struct flow_keys *keys, int hlen)
{
u32 poff = keys->basic.thoff;
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))
return 0;
return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb));
}
static const struct flow_dissector_key flow_keys_dissector_keys[] = {
{
.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),
},
{
.key_id = FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS,
.offset = offsetof(struct flow_keys, addrs),
},
{
.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_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_buf_dissector,
flow_keys_buf_dissector_keys,
ARRAY_SIZE(flow_keys_buf_dissector_keys));
return 0;
}
late_initcall_sync(init_default_flow_dissectors);