nf_conntrack_l4proto.h

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/*
 * Header for use in defining a given L4 protocol for connection tracking.
 *
 * 16 Dec 2003: Yasuyuki Kozakai @USAGI <[email protected]>
 *  - generalized L3 protocol dependent part.
 *
 * Derived from include/linux/netfiter_ipv4/ip_conntrack_protcol.h
 */

#ifndef _NF_CONNTRACK_L4PROTO_H
#define _NF_CONNTRACK_L4PROTO_H
#include <linux/netlink.h>
#include <net/netlink.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netns/generic.h>

struct seq_file;

struct nf_conntrack_l4proto {
    /* L3 Protocol number. */
    u_int16_t l3proto;

    /* L4 Protocol number. */
    u_int8_t l4proto;

    /* Try to fill in the third arg: dataoff is offset past network protocol
           hdr.  Return true if possible. */
    bool (*pkt_to_tuple)(const struct sk_buff *skb, unsigned int dataoff,
                 struct nf_conntrack_tuple *tuple);

    /* Invert the per-proto part of the tuple: ie. turn xmit into reply.
     * Some packets can't be inverted: return 0 in that case.
     */
    bool (*invert_tuple)(struct nf_conntrack_tuple *inverse,
                 const struct nf_conntrack_tuple *orig);

    /* Returns verdict for packet, or -1 for invalid. */
    int (*packet)(struct nf_conn *ct,
              const struct sk_buff *skb,
              unsigned int dataoff,
              enum ip_conntrack_info ctinfo,
              u_int8_t pf,
              unsigned int hooknum,
              unsigned int *timeouts);

    /* Called when a new connection for this protocol found;
     * returns TRUE if it's OK.  If so, packet() called next. */
    bool (*new)(struct nf_conn *ct, const struct sk_buff *skb,
            unsigned int dataoff, unsigned int *timeouts);

    /* Called when a conntrack entry is destroyed */
    void (*destroy)(struct nf_conn *ct);

    int (*error)(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb,
             unsigned int dataoff, enum ip_conntrack_info *ctinfo,
             u_int8_t pf, unsigned int hooknum);

    /* Print out the per-protocol part of the tuple. Return like seq_* */
    int (*print_tuple)(struct seq_file *s,
               const struct nf_conntrack_tuple *);

    /* Print out the private part of the conntrack. */
    int (*print_conntrack)(struct seq_file *s, struct nf_conn *);

    /* Return the array of timeouts for this protocol. */
    unsigned int *(*get_timeouts)(struct net *net);

    /* convert protoinfo to nfnetink attributes */
    int (*to_nlattr)(struct sk_buff *skb, struct nlattr *nla,
             struct nf_conn *ct);
    /* Calculate protoinfo nlattr size */
    int (*nlattr_size)(void);

    /* convert nfnetlink attributes to protoinfo */
    int (*from_nlattr)(struct nlattr *tb[], struct nf_conn *ct);

    int (*tuple_to_nlattr)(struct sk_buff *skb,
                   const struct nf_conntrack_tuple *t);
    /* Calculate tuple nlattr size */
    int (*nlattr_tuple_size)(void);
    int (*nlattr_to_tuple)(struct nlattr *tb[],
                   struct nf_conntrack_tuple *t);
    const struct nla_policy *nla_policy;

    size_t nla_size;

#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
    struct {
        size_t obj_size;
        int (*nlattr_to_obj)(struct nlattr *tb[],
                     struct net *net, void *data);
        int (*obj_to_nlattr)(struct sk_buff *skb, const void *data);

        unsigned int nlattr_max;
        const struct nla_policy *nla_policy;
    } ctnl_timeout;
#endif
    int *net_id;
    /* Init l4proto pernet data */
    int (*init_net)(struct net *net, u_int16_t proto);

    /* Return the per-net protocol part. */
    struct nf_proto_net *(*get_net_proto)(struct net *net);

    /* Protocol name */
    const char *name;

    /* Module (if any) which this is connected to. */
    struct module *me;
};

/* Existing built-in generic protocol */
extern struct nf_conntrack_l4proto nf_conntrack_l4proto_generic;

#define MAX_NF_CT_PROTO 256

extern struct nf_conntrack_l4proto *
__nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto);

extern struct nf_conntrack_l4proto *
nf_ct_l4proto_find_get(u_int16_t l3proto, u_int8_t l4proto);
extern void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p);

/* Protocol registration. */
extern int nf_conntrack_l4proto_register(struct net *net,
                     struct nf_conntrack_l4proto *proto);
extern void nf_conntrack_l4proto_unregister(struct net *net,
                        struct nf_conntrack_l4proto *proto);

static inline void nf_ct_kfree_compat_sysctl_table(struct nf_proto_net *pn)
{
#if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
    kfree(pn->ctl_compat_table);
    pn->ctl_compat_table = NULL;
#endif
}

/* Generic netlink helpers */
extern int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
                      const struct nf_conntrack_tuple *tuple);
extern int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
                      struct nf_conntrack_tuple *t);
extern int nf_ct_port_nlattr_tuple_size(void);
extern const struct nla_policy nf_ct_port_nla_policy[];

#ifdef CONFIG_SYSCTL
#ifdef DEBUG_INVALID_PACKETS
#define LOG_INVALID(net, proto)             \
    ((net)->ct.sysctl_log_invalid == (proto) || \
     (net)->ct.sysctl_log_invalid == IPPROTO_RAW)
#else
#define LOG_INVALID(net, proto)             \
    (((net)->ct.sysctl_log_invalid == (proto) ||    \
      (net)->ct.sysctl_log_invalid == IPPROTO_RAW)  \
     && net_ratelimit())
#endif
#else
static inline int LOG_INVALID(struct net *net, int proto) { return 0; }
#endif /* CONFIG_SYSCTL */

#endif /*_NF_CONNTRACK_PROTOCOL_H*/