systemd/src/libsystemd/sd-netlink/netlink-internal.h

/* SPDX-License-Identifier: LGPL-2.1-or-later */
#pragma once

#include <linux/netlink.h>
#include <sys/socket.h>

#include "forward.h"
#include "list.h"
#include "netlink-types.h"

#define NETLINK_DEFAULT_TIMEOUT_USEC ((usec_t) (25 * USEC_PER_SEC))

#define NETLINK_RQUEUE_MAX 64*1024

#define NETLINK_CONTAINER_DEPTH 32

struct reply_callback {
        sd_netlink_message_handler_t callback;
        usec_t timeout;
        uint32_t serial;
        unsigned prioq_idx;
};

struct match_callback {
        sd_netlink_message_handler_t callback;
        uint32_t *groups;
        size_t n_groups;
        uint16_t type;
        uint8_t cmd; /* used by genl */

        LIST_FIELDS(struct match_callback, match_callbacks);
};

typedef enum NetlinkSlotType {
        NETLINK_REPLY_CALLBACK,
        NETLINK_MATCH_CALLBACK,
        _NETLINK_SLOT_INVALID = -EINVAL,
} NetlinkSlotType;

typedef struct sd_netlink_slot {
        unsigned n_ref;
        NetlinkSlotType type:8;
        bool floating;
        sd_netlink *netlink;
        void *userdata;
        sd_netlink_destroy_t destroy_callback;

        char *description;

        LIST_FIELDS(sd_netlink_slot, slots);

        union {
                struct reply_callback reply_callback;
                struct match_callback match_callback;
        };
} sd_netlink_slot;

typedef struct NetlinkIgnoredSerial {
        uint32_t serial;
        usec_t timeout_usec; /* timestamp in CLOCK_MONOTONIC */
} NetlinkIgnoredSerial;

typedef struct sd_netlink {
        unsigned n_ref;

        int fd;

        union {
                struct sockaddr sa;
                struct sockaddr_nl nl;
        } sockaddr;

        int protocol;

        Hashmap *broadcast_group_refs;

        OrderedSet *rqueue;
        Hashmap *rqueue_by_serial;
        Hashmap *rqueue_partial_by_serial;

        struct nlmsghdr *rbuffer;

        bool processing:1;

        uint32_t serial;
        Hashmap *ignored_serials;

        struct Prioq *reply_callbacks_prioq;
        Hashmap *reply_callbacks;

        LIST_HEAD(struct match_callback, match_callbacks);

        LIST_HEAD(sd_netlink_slot, slots);

        pid_t original_pid;

        sd_event_source *io_event_source;
        sd_event_source *time_event_source;
        sd_event_source *exit_event_source;
        sd_event *event;

        Hashmap *genl_family_by_name;
        Hashmap *genl_family_by_id;
} sd_netlink;

struct netlink_attribute {
        size_t offset; /* offset from hdr to attribute */
        bool nested:1;
        bool net_byteorder:1;
};

struct netlink_container {
        const struct NLAPolicySet *policy_set; /* the policy set of the container */
        size_t offset; /* offset from hdr to the start of the container */
        struct netlink_attribute *attributes;
        uint16_t max_attribute; /* the maximum attribute in container */
};

typedef struct sd_netlink_message {
        unsigned n_ref;

        int protocol;

        struct nlmsghdr *hdr;
        struct netlink_container containers[NETLINK_CONTAINER_DEPTH];
        unsigned n_containers; /* number of containers */
        uint32_t multicast_group;
        bool sealed:1;

        sd_netlink_message *next; /* next in a chain of multi-part messages */
        sd_netlink_message *tail; /* last message in a multi-part chain */
} sd_netlink_message;

int message_new_empty(sd_netlink *nl, sd_netlink_message **ret);
int message_new_full(
                sd_netlink *nl,
                uint16_t nlmsg_type,
                uint16_t nlmsg_flags,
                const NLAPolicySet *policy_set,
                size_t header_size,
                sd_netlink_message **ret);
int message_new(sd_netlink *nl, sd_netlink_message **ret, uint16_t type, uint16_t flags);
int message_new_synthetic_error(sd_netlink *nl, int error, uint32_t serial, sd_netlink_message **ret);

static inline uint32_t message_get_serial(sd_netlink_message *m) {
        assert(m);
        return ASSERT_PTR(m->hdr)->nlmsg_seq;
}

void message_seal(sd_netlink_message *m);

int netlink_open_family(sd_netlink **ret, int family);
bool netlink_pid_changed(sd_netlink *nl);

int socket_bind(sd_netlink *nl);
int socket_broadcast_group_ref(sd_netlink *nl, unsigned group);
int socket_broadcast_group_unref(sd_netlink *nl, unsigned group);
int socket_write_message(sd_netlink *nl, sd_netlink_message *m);
int socket_read_message(sd_netlink *nl);

int netlink_add_match_internal(
                sd_netlink *nl,
                sd_netlink_slot **ret_slot,
                const uint32_t *groups,
                size_t n_groups,
                uint16_t type,
                uint8_t cmd,
                sd_netlink_message_handler_t callback,
                sd_netlink_destroy_t destroy_callback,
                void *userdata,
                const char *description);

/* Make sure callbacks don't destroy the netlink connection */
#define NETLINK_DONT_DESTROY(nl) \
        _cleanup_(sd_netlink_unrefp) _unused_ sd_netlink *_dont_destroy_##nl = sd_netlink_ref(nl)

bool nfproto_is_valid(int nfproto);

/* nfnl */
/* TODO: to be exported later */
int sd_nfnl_socket_open(sd_netlink **ret);
int sd_nfnl_send_batch(
                sd_netlink *nfnl,
                sd_netlink_message **messages,
                size_t n_messages,
                uint32_t **ret_serials);
int sd_nfnl_call_batch(
                sd_netlink *nfnl,
                sd_netlink_message **messages,
                size_t n_messages,
                uint64_t usec);
int sd_nfnl_message_new(
                sd_netlink *nfnl,
                sd_netlink_message **ret,
                int nfproto,
                uint16_t subsys,
                uint16_t msg_type,
                uint16_t flags);
int sd_nfnl_nft_message_new_table(
                sd_netlink *nfnl,
                sd_netlink_message **ret,
                int add,
                int nfproto,
                const char *table);
int sd_nfnl_nft_message_new_basechain(
                sd_netlink *nfnl,
                sd_netlink_message **ret,
                int add,
                int nfproto,
                const char *table,
                const char *chain,
                const char *type,
                uint8_t hook,
                int prio);
int sd_nfnl_nft_message_new_rule(
                sd_netlink *nfnl,
                sd_netlink_message **ret,
                int add,
                int nfproto,
                const char *table,
                const char *chain);
int sd_nfnl_nft_message_new_set(
                sd_netlink *nfnl,
                sd_netlink_message **ret,
                int add,
                int nfproto,
                const char *table,
                const char *set_name,
                uint32_t set_id,
                uint32_t klen);
int sd_nfnl_nft_message_new_setelems(
                sd_netlink *nfnl,
                sd_netlink_message **ret,
                int add,
                int nfproto,
                const char *table,
                const char *set_name);
int sd_nfnl_nft_message_append_setelem(
                sd_netlink_message *m,
                uint32_t index,
                const void *key,
                size_t key_len,
                const void *data,
                size_t data_len,
                uint32_t flags);