fs: fix over-zealous use of "const"

[linux-2.6/btrfs-unstable.git] / net / core / flow_dissector.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);

/**
 * __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_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_buf_dissector,
                                flow_keys_buf_dissector_keys,
                                ARRAY_SIZE(flow_keys_buf_dissector_keys));
        return 0;
}

late_initcall_sync(init_default_flow_dissectors);