root/include/net/dst_metadata.h
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __NET_DST_METADATA_H
#define __NET_DST_METADATA_H 1

#include <linux/skbuff.h>
#include <net/ip.h>
#include <net/ip_tunnels.h>
#include <net/macsec.h>
#include <net/dst.h>

enum metadata_type {
        METADATA_IP_TUNNEL,
        METADATA_HW_PORT_MUX,
        METADATA_MACSEC,
        METADATA_XFRM,
};

struct hw_port_info {
        struct net_device *lower_dev;
        u32 port_id;
};

struct macsec_info {
        sci_t sci;
};

struct xfrm_md_info {
        u32 if_id;
        int link;
        struct dst_entry *dst_orig;
};

struct metadata_dst {
        struct dst_entry                dst;
        enum metadata_type              type;
        union {
                struct ip_tunnel_info   tun_info;
                struct hw_port_info     port_info;
                struct macsec_info      macsec_info;
                struct xfrm_md_info     xfrm_info;
        } u;
};

static inline struct metadata_dst *skb_metadata_dst(const struct sk_buff *skb)
{
        struct metadata_dst *md_dst = (struct metadata_dst *) skb_dst(skb);

        if (md_dst && md_dst->dst.flags & DST_METADATA)
                return md_dst;

        return NULL;
}

static inline struct ip_tunnel_info *
skb_tunnel_info(const struct sk_buff *skb)
{
        struct metadata_dst *md_dst = skb_metadata_dst(skb);
        struct dst_entry *dst;

        if (md_dst && md_dst->type == METADATA_IP_TUNNEL)
                return &md_dst->u.tun_info;

        dst = skb_dst(skb);
        if (dst && dst->lwtstate &&
            (dst->lwtstate->type == LWTUNNEL_ENCAP_IP ||
             dst->lwtstate->type == LWTUNNEL_ENCAP_IP6))
                return lwt_tun_info(dst->lwtstate);

        return NULL;
}

static inline struct xfrm_md_info *lwt_xfrm_info(struct lwtunnel_state *lwt)
{
        return (struct xfrm_md_info *)lwt->data;
}

static inline struct xfrm_md_info *skb_xfrm_md_info(const struct sk_buff *skb)
{
        struct metadata_dst *md_dst = skb_metadata_dst(skb);
        struct dst_entry *dst;

        if (md_dst && md_dst->type == METADATA_XFRM)
                return &md_dst->u.xfrm_info;

        dst = skb_dst(skb);
        if (dst && dst->lwtstate &&
            dst->lwtstate->type == LWTUNNEL_ENCAP_XFRM)
                return lwt_xfrm_info(dst->lwtstate);

        return NULL;
}

static inline bool skb_valid_dst(const struct sk_buff *skb)
{
        struct dst_entry *dst = skb_dst(skb);

        return dst && !(dst->flags & DST_METADATA);
}

static inline int skb_metadata_dst_cmp(const struct sk_buff *skb_a,
                                       const struct sk_buff *skb_b)
{
        const struct metadata_dst *a, *b;

        if (!(skb_a->_skb_refdst | skb_b->_skb_refdst))
                return 0;

        a = (const struct metadata_dst *) skb_dst(skb_a);
        b = (const struct metadata_dst *) skb_dst(skb_b);

        if (!a != !b || a->type != b->type)
                return 1;

        switch (a->type) {
        case METADATA_HW_PORT_MUX:
                return memcmp(&a->u.port_info, &b->u.port_info,
                              sizeof(a->u.port_info));
        case METADATA_IP_TUNNEL:
                return memcmp(&a->u.tun_info, &b->u.tun_info,
                              sizeof(a->u.tun_info) +
                                         a->u.tun_info.options_len);
        case METADATA_MACSEC:
                return memcmp(&a->u.macsec_info, &b->u.macsec_info,
                              sizeof(a->u.macsec_info));
        case METADATA_XFRM:
                return memcmp(&a->u.xfrm_info, &b->u.xfrm_info,
                              sizeof(a->u.xfrm_info));
        default:
                return 1;
        }
}

void metadata_dst_free(struct metadata_dst *);
struct metadata_dst *metadata_dst_alloc(u8 optslen, enum metadata_type type,
                                        gfp_t flags);
void metadata_dst_free_percpu(struct metadata_dst __percpu *md_dst);
struct metadata_dst __percpu *
metadata_dst_alloc_percpu(u8 optslen, enum metadata_type type, gfp_t flags);

static inline struct metadata_dst *tun_rx_dst(int md_size)
{
        struct metadata_dst *tun_dst;

        tun_dst = metadata_dst_alloc(md_size, METADATA_IP_TUNNEL, GFP_ATOMIC);
        if (!tun_dst)
                return NULL;

        tun_dst->u.tun_info.options_len = 0;
        tun_dst->u.tun_info.mode = 0;
        return tun_dst;
}

static inline struct metadata_dst *tun_dst_unclone(struct sk_buff *skb)
{
        struct metadata_dst *md_dst = skb_metadata_dst(skb);
        int md_size;
        struct metadata_dst *new_md;

        if (!md_dst || md_dst->type != METADATA_IP_TUNNEL)
                return ERR_PTR(-EINVAL);

        md_size = md_dst->u.tun_info.options_len;
        new_md = metadata_dst_alloc(md_size, METADATA_IP_TUNNEL, GFP_ATOMIC);
        if (!new_md)
                return ERR_PTR(-ENOMEM);

        memcpy(&new_md->u.tun_info, &md_dst->u.tun_info,
               sizeof(struct ip_tunnel_info) + md_size);
#ifdef CONFIG_DST_CACHE
        /* Unclone the dst cache if there is one */
        if (new_md->u.tun_info.dst_cache.cache) {
                int ret;

                ret = dst_cache_init(&new_md->u.tun_info.dst_cache, GFP_ATOMIC);
                if (ret) {
                        metadata_dst_free(new_md);
                        return ERR_PTR(ret);
                }
        }
#endif

        skb_dst_drop(skb);
        skb_dst_set(skb, &new_md->dst);
        return new_md;
}

static inline struct ip_tunnel_info *skb_tunnel_info_unclone(struct sk_buff *skb)
{
        struct metadata_dst *dst;

        dst = tun_dst_unclone(skb);
        if (IS_ERR(dst))
                return NULL;

        return &dst->u.tun_info;
}

static inline struct metadata_dst *__ip_tun_set_dst(__be32 saddr,
                                                    __be32 daddr,
                                                    __u8 tos, __u8 ttl,
                                                    __be16 tp_dst,
                                                    const unsigned long *flags,
                                                    __be64 tunnel_id,
                                                    int md_size)
{
        struct metadata_dst *tun_dst;

        tun_dst = tun_rx_dst(md_size);
        if (!tun_dst)
                return NULL;

        ip_tunnel_key_init(&tun_dst->u.tun_info.key,
                           saddr, daddr, tos, ttl,
                           0, 0, tp_dst, tunnel_id, flags);
        return tun_dst;
}

static inline struct metadata_dst *ip_tun_rx_dst(struct sk_buff *skb,
                                                 const unsigned long *flags,
                                                 __be64 tunnel_id,
                                                 int md_size)
{
        const struct iphdr *iph = ip_hdr(skb);
        struct metadata_dst *tun_dst;

        tun_dst = __ip_tun_set_dst(iph->saddr, iph->daddr, iph->tos, iph->ttl,
                                   0, flags, tunnel_id, md_size);

        if (tun_dst && (iph->frag_off & htons(IP_DF)))
                __set_bit(IP_TUNNEL_DONT_FRAGMENT_BIT,
                          tun_dst->u.tun_info.key.tun_flags);
        return tun_dst;
}

static inline struct metadata_dst *__ipv6_tun_set_dst(const struct in6_addr *saddr,
                                                      const struct in6_addr *daddr,
                                                      __u8 tos, __u8 ttl,
                                                      __be16 tp_dst,
                                                      __be32 label,
                                                      const unsigned long *flags,
                                                      __be64 tunnel_id,
                                                      int md_size)
{
        struct metadata_dst *tun_dst;
        struct ip_tunnel_info *info;

        tun_dst = tun_rx_dst(md_size);
        if (!tun_dst)
                return NULL;

        info = &tun_dst->u.tun_info;
        info->mode = IP_TUNNEL_INFO_IPV6;
        ip_tunnel_flags_copy(info->key.tun_flags, flags);
        info->key.tun_id = tunnel_id;
        info->key.tp_src = 0;
        info->key.tp_dst = tp_dst;

        info->key.u.ipv6.src = *saddr;
        info->key.u.ipv6.dst = *daddr;

        info->key.tos = tos;
        info->key.ttl = ttl;
        info->key.label = label;

        return tun_dst;
}

static inline struct metadata_dst *ipv6_tun_rx_dst(struct sk_buff *skb,
                                                   const unsigned long *flags,
                                                   __be64 tunnel_id,
                                                   int md_size)
{
        const struct ipv6hdr *ip6h = ipv6_hdr(skb);

        return __ipv6_tun_set_dst(&ip6h->saddr, &ip6h->daddr,
                                  ipv6_get_dsfield(ip6h), ip6h->hop_limit,
                                  0, ip6_flowlabel(ip6h), flags, tunnel_id,
                                  md_size);
}
#endif /* __NET_DST_METADATA_H */