/* SPDX-License-Identifier: GPL-2.0 */
#ifndef MPLS_INTERNAL_H
#define MPLS_INTERNAL_H
#include <net/mpls.h>

/* put a reasonable limit on the number of labels
 * we will accept from userspace
 */
#define MAX_NEW_LABELS 30

struct mpls_entry_decoded {
        u32 label;
        u8 ttl;
        u8 tc;
        u8 bos;
};

struct mpls_pcpu_stats {
        struct mpls_link_stats  stats;
        struct u64_stats_sync   syncp;
};

struct mpls_dev {
        int                             input_enabled;
        struct net_device               *dev;
        struct mpls_pcpu_stats __percpu *stats;

        struct ctl_table_header         *sysctl;
        struct rcu_head                 rcu;
};

#if BITS_PER_LONG == 32

#define MPLS_INC_STATS_LEN(mdev, len, pkts_field, bytes_field)          \
        do {                                                            \
                TYPEOF_UNQUAL(*(mdev)->stats) *ptr =                    \
                        raw_cpu_ptr((mdev)->stats);                     \
                local_bh_disable();                                     \
                u64_stats_update_begin(&ptr->syncp);                    \
                ptr->stats.pkts_field++;                                \
                ptr->stats.bytes_field += (len);                        \
                u64_stats_update_end(&ptr->syncp);                      \
                local_bh_enable();                                      \
        } while (0)

#define MPLS_INC_STATS(mdev, field)                                     \
        do {                                                            \
                TYPEOF_UNQUAL(*(mdev)->stats) *ptr =                    \
                        raw_cpu_ptr((mdev)->stats);                     \
                local_bh_disable();                                     \
                u64_stats_update_begin(&ptr->syncp);                    \
                ptr->stats.field++;                                     \
                u64_stats_update_end(&ptr->syncp);                      \
                local_bh_enable();                                      \
        } while (0)

#else

#define MPLS_INC_STATS_LEN(mdev, len, pkts_field, bytes_field)          \
        do {                                                            \
                this_cpu_inc((mdev)->stats->stats.pkts_field);          \
                this_cpu_add((mdev)->stats->stats.bytes_field, (len));  \
        } while (0)

#define MPLS_INC_STATS(mdev, field)                     \
        this_cpu_inc((mdev)->stats->stats.field)

#endif

struct sk_buff;

#define LABEL_NOT_SPECIFIED (1 << 20)

/* This maximum ha length copied from the definition of struct neighbour */
#define VIA_ALEN_ALIGN sizeof(unsigned long)
#define MAX_VIA_ALEN (ALIGN(MAX_ADDR_LEN, VIA_ALEN_ALIGN))

enum mpls_payload_type {
        MPT_UNSPEC, /* IPv4 or IPv6 */
        MPT_IPV4 = 4,
        MPT_IPV6 = 6,

        /* Other types not implemented:
         *  - Pseudo-wire with or without control word (RFC4385)
         *  - GAL (RFC5586)
         */
};

struct mpls_nh { /* next hop label forwarding entry */
        struct net_device       *nh_dev;
        netdevice_tracker       nh_dev_tracker;

        /* nh_flags is accessed under RCU in the packet path; it is
         * modified handling netdev events with rtnl lock held
         */
        unsigned int            nh_flags;
        u8                      nh_labels;
        u8                      nh_via_alen;
        u8                      nh_via_table;
        u8                      nh_reserved1;

        u32                     nh_label[];
};

/* offset of via from beginning of mpls_nh */
#define MPLS_NH_VIA_OFF(num_labels) \
                ALIGN(sizeof(struct mpls_nh) + (num_labels) * sizeof(u32), \
                      VIA_ALEN_ALIGN)

/* all nexthops within a route have the same size based on the
 * max number of labels and max via length across all nexthops
 */
#define MPLS_NH_SIZE(num_labels, max_via_alen)          \
                (MPLS_NH_VIA_OFF((num_labels)) +        \
                ALIGN((max_via_alen), VIA_ALEN_ALIGN))

enum mpls_ttl_propagation {
        MPLS_TTL_PROP_DEFAULT,
        MPLS_TTL_PROP_ENABLED,
        MPLS_TTL_PROP_DISABLED,
};

/* The route, nexthops and vias are stored together in the same memory
 * block:
 *
 * +----------------------+
 * | mpls_route           |
 * +----------------------+
 * | mpls_nh 0            |
 * +----------------------+
 * | alignment padding    |   4 bytes for odd number of labels
 * +----------------------+
 * | via[rt_max_alen] 0   |
 * +----------------------+
 * | alignment padding    |   via's aligned on sizeof(unsigned long)
 * +----------------------+
 * | ...                  |
 * +----------------------+
 * | mpls_nh n-1          |
 * +----------------------+
 * | via[rt_max_alen] n-1 |
 * +----------------------+
 */
struct mpls_route { /* next hop label forwarding entry */
        struct rcu_head         rt_rcu;
        u8                      rt_protocol;
        u8                      rt_payload_type;
        u8                      rt_max_alen;
        u8                      rt_ttl_propagate;
        u8                      rt_nhn;
        /* rt_nhn_alive is accessed under RCU in the packet path; it
         * is modified handling netdev events with rtnl lock held
         */
        u8                      rt_nhn_alive;
        u8                      rt_nh_size;
        u8                      rt_via_offset;
        u8                      rt_reserved1;
        struct mpls_nh          rt_nh[];
};

#define for_nexthops(rt) {                                              \
        int nhsel; const struct mpls_nh *nh;                            \
        for (nhsel = 0, nh = (rt)->rt_nh;                               \
             nhsel < (rt)->rt_nhn;                                      \
             nh = (void *)nh + (rt)->rt_nh_size, nhsel++)

#define change_nexthops(rt) {                                           \
        int nhsel; struct mpls_nh *nh;                                  \
        for (nhsel = 0, nh = (rt)->rt_nh;                               \
             nhsel < (rt)->rt_nhn;                                      \
             nh = (void *)nh + (rt)->rt_nh_size, nhsel++)

#define endfor_nexthops(rt) }

static inline struct mpls_entry_decoded mpls_entry_decode(struct mpls_shim_hdr *hdr)
{
        struct mpls_entry_decoded result;
        unsigned entry = be32_to_cpu(hdr->label_stack_entry);

        result.label = (entry & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT;
        result.ttl = (entry & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT;
        result.tc =  (entry & MPLS_LS_TC_MASK) >> MPLS_LS_TC_SHIFT;
        result.bos = (entry & MPLS_LS_S_MASK) >> MPLS_LS_S_SHIFT;

        return result;
}

#define mpls_dereference(net, p)                                        \
        rcu_dereference_protected(                                      \
                (p),                                                    \
                lockdep_is_held(&(net)->mpls.platform_mutex))

static inline struct mpls_dev *mpls_dev_rcu(const struct net_device *dev)
{
        return rcu_dereference(dev->mpls_ptr);
}

static inline struct mpls_dev *mpls_dev_get(const struct net *net,
                                            const struct net_device *dev)
{
        return mpls_dereference(net, dev->mpls_ptr);
}

int nla_put_labels(struct sk_buff *skb, int attrtype,  u8 labels,
                   const u32 label[]);
int nla_get_labels(const struct nlattr *nla, u8 max_labels, u8 *labels,
                   u32 label[], struct netlink_ext_ack *extack);
bool mpls_output_possible(const struct net_device *dev);
unsigned int mpls_dev_mtu(const struct net_device *dev);
bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu);
void mpls_stats_inc_outucastpkts(struct net *net,
                                 struct net_device *dev,
                                 const struct sk_buff *skb);

#endif /* MPLS_INTERNAL_H */