Linux Kernel TIPC¶

Introduction¶

TIPC (Transparent Inter Process Communication) is a protocol that is specially designed for intra-cluster communication. It can be configured to transmit messages either on UDP or directly across Ethernet. Message delivery is sequence guaranteed, loss free and flow controlled. Latency times are shorter than with any other known protocol, while maximal throughput is comparable to that of TCP.

TIPC Features¶

Cluster wide IPC service

Have you ever wished you had the convenience of Unix Domain Sockets even when transmitting data between cluster nodes? Where you yourself determine the addresses you want to bind to and use? Where you don’t have to perform DNS lookups and worry about IP addresses? Where you don’t have to start timers to monitor the continuous existence of peer sockets? And yet without the downsides of that socket type, such as the risk of lingering inodes?

Welcome to the Transparent Inter Process Communication service, TIPC in short, which gives you all of this, and a lot more.
Service Addressing

A fundamental concept in TIPC is that of Service Addressing which makes it possible for a programmer to chose his own address, bind it to a server socket and let client programs use only that address for sending messages.
Service Tracking

A client wanting to wait for the availability of a server, uses the Service Tracking mechanism to subscribe for binding and unbinding/close events for sockets with the associated service address.

The service tracking mechanism can also be used for Cluster Topology Tracking, i.e., subscribing for availability/non-availability of cluster nodes.

Likewise, the service tracking mechanism can be used for Cluster Connectivity Tracking, i.e., subscribing for up/down events for individual links between cluster nodes.
Transmission Modes

Using a service address, a client can send datagram messages to a server socket.

Using the same address type, it can establish a connection towards an accepting server socket.

It can also use a service address to create and join a Communication Group, which is the TIPC manifestation of a brokerless message bus.

Multicast with very good performance and scalability is available both in datagram mode and in communication group mode.
Inter Node Links

Communication between any two nodes in a cluster is maintained by one or two Inter Node Links, which both guarantee data traffic integrity and monitor the peer node’s availability.
Cluster Scalability

By applying the Overlapping Ring Monitoring algorithm on the inter node links it is possible to scale TIPC clusters up to 1000 nodes with a maintained neighbor failure discovery time of 1-2 seconds. For smaller clusters this time can be made much shorter.
Neighbor Discovery

Neighbor Node Discovery in the cluster is done by Ethernet broadcast or UDP multicast, when any of those services are available. If not, configured peer IP addresses can be used.
Configuration

When running TIPC in single node mode no configuration whatsoever is needed. When running in cluster mode TIPC must as a minimum be given a node address (before Linux 4.17) and told which interface to attach to. The “tipc” configuration tool makes is possible to add and maintain many more configuration parameters.
Performance

TIPC message transfer latency times are better than in any other known protocol. Maximal byte throughput for inter-node connections is still somewhat lower than for TCP, while they are superior for intra-node and inter-container throughput on the same host.
Language Support

The TIPC user API has support for C, Python, Perl, Ruby, D and Go.

More Information¶

How to set up TIPC:

http://tipc.io/getting_started.html
How to program with TIPC:

http://tipc.io/programming.html
How to contribute to TIPC:
http://tipc.io/contacts.html
More details about TIPC specification:

http://tipc.io/protocol.html

Implementation¶

TIPC is implemented as a kernel module in net/tipc/ directory.

TIPC Base Types¶

struct tipc_subscription¶: TIPC network topology subscription object

Definition

struct tipc_subscription {
  struct tipc_subscr s;
  struct tipc_event evt;
  struct kref kref;
  struct net *net;
  struct timer_list timer;
  struct list_head service_list;
  struct list_head sub_list;
  int conid;
  bool inactive;
  spinlock_t lock;
};

Members

s: host-endian copy of the user subscription
evt: template for events generated by subscription
kref: reference count for this subscription
net: network namespace associated with subscription
timer: timer governing subscription duration (optional)
service_list: adjacent subscriptions in name sequence’s subscription list
sub_list: adjacent subscriptions in subscriber’s subscription list
conid: connection identifier of topology server
inactive: true if this subscription is inactive
lock: serialize up/down and timer events

struct tipc_media_addr¶: destination address used by TIPC bearers

Definition

struct tipc_media_addr {
  u8 value[TIPC_MEDIA_INFO_SIZE];
  u8 media_id;
  u8 broadcast;
};

Members

value: address info (format defined by media)
media_id: TIPC media type identifier
broadcast: non-zero if address is a broadcast address

struct tipc_media¶: Media specific info exposed to generic bearer layer

Definition

struct tipc_media {
  int (*send_msg)(struct net *net, struct sk_buff *buf,struct tipc_bearer *b, struct tipc_media_addr *dest);
  int (*enable_media)(struct net *net, struct tipc_bearer *b, struct nlattr *attr[]);
  void (*disable_media)(struct tipc_bearer *b);
  int (*addr2str)(struct tipc_media_addr *addr,char *strbuf, int bufsz);
  int (*addr2msg)(char *msg, struct tipc_media_addr *addr);
  int (*msg2addr)(struct tipc_bearer *b,struct tipc_media_addr *addr, char *msg);
  int (*raw2addr)(struct tipc_bearer *b,struct tipc_media_addr *addr, char *raw);
  u32 priority;
  u32 tolerance;
  u32 min_win;
  u32 max_win;
  u32 mtu;
  u32 type_id;
  u32 hwaddr_len;
  char name[TIPC_MAX_MEDIA_NAME];
};

Members

send_msg: routine which handles buffer transmission
enable_media: routine which enables a media
disable_media: routine which disables a media
addr2str: convert media address format to string
addr2msg: convert from media addr format to discovery msg addr format
msg2addr: convert from discovery msg addr format to media addr format
raw2addr: convert from raw addr format to media addr format
priority: default link (and bearer) priority
tolerance: default time (in ms) before declaring link failure
min_win: minimum window (in packets) before declaring link congestion
max_win: maximum window (in packets) before declaring link congestion
mtu: max packet size bearer can support for media type not dependent on underlying device MTU
type_id: TIPC media identifier
hwaddr_len: TIPC media address len
name: media name

struct tipc_bearer¶: Generic TIPC bearer structure

Definition

struct tipc_bearer {
  void __rcu *media_ptr;
  u32 mtu;
  struct tipc_media_addr addr;
  char name[TIPC_MAX_BEARER_NAME];
  struct tipc_media *media;
  struct tipc_media_addr bcast_addr;
  struct packet_type pt;
  struct rcu_head rcu;
  u32 priority;
  u32 min_win;
  u32 max_win;
  u32 tolerance;
  u32 domain;
  u32 identity;
  struct tipc_discoverer *disc;
  char net_plane;
  unsigned long up;
  refcount_t refcnt;
};

Members

media_ptr: pointer to additional media-specific information about bearer
mtu: max packet size bearer can support
addr: media-specific address associated with bearer
name: bearer name (format = media:interface)
media: ptr to media structure associated with bearer
bcast_addr: media address used in broadcasting
pt: packet type for bearer
rcu: rcu struct for tipc_bearer
priority: default link priority for bearer
min_win: minimum window (in packets) before declaring link congestion
max_win: maximum window (in packets) before declaring link congestion
tolerance: default link tolerance for bearer
domain: network domain to which links can be established
identity: array index of this bearer within TIPC bearer array
disc: ptr to link setup request
net_plane: network plane (‘A’ through ‘H’) currently associated with bearer
up: bearer up flag (bit 0)
refcnt: tipc_bearer reference counter

Note

media-specific code is responsible for initialization of the fields indicated below when a bearer is enabled; TIPC’s generic bearer code takes care of initializing all other fields.

struct publication¶: info about a published service address or range

Definition

struct publication {
  struct tipc_service_range sr;
  struct tipc_socket_addr sk;
  u16 scope;
  u32 key;
  u32 id;
  struct list_head binding_node;
  struct list_head binding_sock;
  struct list_head local_publ;
  struct list_head all_publ;
  struct list_head list;
  struct rcu_head rcu;
};

Members

sr: service range represented by this publication
sk: address of socket bound to this publication
scope: scope of publication, TIPC_NODE_SCOPE or TIPC_CLUSTER_SCOPE
key: publication key, unique across the cluster
id: publication id
binding_node: all publications from the same node which bound this one - Remote publications: in node->publ_list; Used by node/name distr to withdraw publications when node is lost - Local/node scope publications: in name_table->node_scope list - Local/cluster scope publications: in name_table->cluster_scope list
binding_sock: all publications from the same socket which bound this one Used by socket to withdraw publications when socket is unbound/released
local_publ: list of identical publications made from this node Used by closest_first and multicast receive lookup algorithms
all_publ: all publications identical to this one, whatever node and scope Used by round-robin lookup algorithm
list: to form a list of publications in temporal order
rcu: RCU callback head used for deferred freeing

struct name_table¶: table containing all existing port name publications

Definition

struct name_table {
  struct hlist_head services[TIPC_NAMETBL_SIZE];
  struct list_head node_scope;
  struct list_head cluster_scope;
  rwlock_t cluster_scope_lock;
  u32 local_publ_count;
  u32 rc_dests;
  u32 snd_nxt;
};

Members

services: name sequence hash lists
node_scope: all local publications with node scope - used by name_distr during re-init of name table
cluster_scope: all local publications with cluster scope - used by name_distr to send bulk updates to new nodes - used by name_distr during re-init of name table
cluster_scope_lock: lock for accessing cluster_scope
local_publ_count: number of publications issued by this node
rc_dests: destination node counter
snd_nxt: next sequence number to be used

struct distr_item¶: publication info distributed to other nodes

Definition

struct distr_item {
  __be32 type;
  __be32 lower;
  __be32 upper;
  __be32 port;
  __be32 key;
};

Members

type: name sequence type
lower: name sequence lower bound
upper: name sequence upper bound
port: publishing port reference
key: publication key

Description

===> All fields are stored in network byte order. <===

First 3 fields identify (name or) name sequence being published. Reference field uniquely identifies port that published name sequence. Key field uniquely identifies publication, in the event a port has multiple publications of the same name sequence.

Note

There is no field that identifies the publishing node because it is the same for all items contained within a publication message.

struct tipc_bc_base¶: base structure for keeping broadcast send state

Definition

struct tipc_bc_base {
  struct tipc_link *link;
  struct sk_buff_head inputq;
  int dests[MAX_BEARERS];
  int primary_bearer;
  bool bcast_support;
  bool force_bcast;
  bool rcast_support;
  bool force_rcast;
  int rc_ratio;
  int bc_threshold;
};

Members

link: broadcast send link structure
inputq: data input queue; will only carry SOCK_WAKEUP messages
dests: array keeping number of reachable destinations per bearer
primary_bearer: a bearer having links to all broadcast destinations, if any
bcast_support: indicates if primary bearer, if any, supports broadcast
force_bcast: forces broadcast for multicast traffic
rcast_support: indicates if all peer nodes support replicast
force_rcast: forces replicast for multicast traffic
rc_ratio: dest count as percentage of cluster size where send method changes
bc_threshold: calculated from rc_ratio; if dests > threshold use broadcast

TIPC Bearer Interfaces¶

struct tipc_media * tipc_media_find(const char *name)¶: locates specified media object by name

Parameters

const char *name: name to locate

struct tipc_media * media_find_id(u8 type)¶: locates specified media object by type identifier

Parameters

u8 type: type identifier to locate

int tipc_media_addr_printf(char *buf, int len, struct tipc_media_addr *a)¶: record media address in print buffer

Parameters

char *buf: output buffer
int len: output buffer size remaining
struct tipc_media_addr *a: input media address

int bearer_name_validate(const char *name, struct tipc_bearer_names *name_parts)¶: validate & (optionally) deconstruct bearer name

Parameters

const char *name: ptr to bearer name string
struct tipc_bearer_names *name_parts: ptr to area for bearer name components (or NULL if not needed)

Return

1 if bearer name is valid, otherwise 0.

struct tipc_bearer * tipc_bearer_find(struct net *net, const char *name)¶: locates bearer object with matching bearer name

Parameters

struct net *net: the applicable net namespace
const char *name: bearer name to locate

int tipc_enable_bearer(struct net *net, const char *name, u32 disc_domain, u32 prio, struct nlattr *attr[], struct netlink_ext_ack *extack)¶: enable bearer with the given name

Parameters

struct net *net: the applicable net namespace
const char *name: bearer name to enable
u32 disc_domain: bearer domain
u32 prio: bearer priority
struct nlattr *attr[]: nlattr array
struct netlink_ext_ack *extack: netlink extended ack

int tipc_reset_bearer(struct net *net, struct tipc_bearer *b)¶: Reset all links established over this bearer

Parameters

struct net *net: the applicable net namespace
struct tipc_bearer *b: the target bearer

void bearer_disable(struct net *net, struct tipc_bearer *b)¶: disable this bearer

Parameters

struct net *net: the applicable net namespace
struct tipc_bearer *b: the bearer to disable

Note

This routine assumes caller holds RTNL lock.

int tipc_l2_send_msg(struct net *net, struct sk_buff *skb, struct tipc_bearer *b, struct tipc_media_addr *dest)¶: send a TIPC packet out over an L2 interface

Parameters

struct net *net: the associated network namespace
struct sk_buff *skb: the packet to be sent
struct tipc_bearer *b: the bearer through which the packet is to be sent
struct tipc_media_addr *dest: peer destination address

int tipc_l2_rcv_msg(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)¶: handle incoming TIPC message from an interface

Parameters

struct sk_buff *skb: the received message
struct net_device *dev: the net device that the packet was received on
struct packet_type *pt: the packet_type structure which was used to register this handler
struct net_device *orig_dev: the original receive net device in case the device is a bond

Description

Accept only packets explicitly sent to this node, or broadcast packets; ignores packets sent using interface multicast, and traffic sent to other nodes (which can happen if interface is running in promiscuous mode).

int tipc_l2_device_event(struct notifier_block *nb, unsigned long evt, void *ptr)¶: handle device events from network device

Parameters

struct notifier_block *nb: the context of the notification
unsigned long evt: the type of event
void *ptr: the net device that the event was on

Description

This function is called by the Ethernet driver in case of link change event.

struct udp_media_addr¶: IP/UDP addressing information

Definition

struct udp_media_addr {
  __be16 proto;
  __be16 port;
  union {
    struct in_addr ipv4;
    struct in6_addr ipv6;
  };
};

Members

proto: Ethernet protocol in use
port: port being used
{unnamed_union}: anonymous
ipv4: IPv4 address of neighbor
ipv6: IPv6 address of neighbor

Description

This is the bearer level originating address used in neighbor discovery messages, and all fields should be in network byte order

struct udp_bearer¶: ip/udp bearer data structure

Definition

struct udp_bearer {
  struct tipc_bearer __rcu *bearer;
  struct socket *ubsock;
  u32 ifindex;
  struct work_struct work;
  struct udp_replicast rcast;
};

Members

bearer: associated generic tipc bearer
ubsock: bearer associated socket
ifindex: local address scope
work: used to schedule deferred work on a bearer
rcast: associated udp_replicast container

int tipc_parse_udp_addr(struct nlattr *nla, struct udp_media_addr *addr, u32 *scope_id)¶: build udp media address from netlink data

Parameters

struct nlattr *nla: netlink attribute containing sockaddr storage aligned address
struct udp_media_addr *addr: tipc media address to fill with address, port and protocol type
u32 *scope_id: IPv6 scope id pointer, not NULL indicates it’s required

int tipc_udp_enable(struct net *net, struct tipc_bearer *b, struct nlattr *attrs[])¶: callback to create a new udp bearer instance

Parameters

struct net *net: network namespace
struct tipc_bearer *b: pointer to generic tipc_bearer
struct nlattr *attrs[]: netlink bearer configuration

Description

validate the bearer parameters and initialize the udp bearer rtnl_lock should be held

TIPC Crypto Interfaces¶

struct tipc_tfm¶: TIPC TFM structure to form a list of TFMs

Definition

struct tipc_tfm {
  struct crypto_aead *tfm;
  struct list_head list;
};

Members

tfm: cipher handle/key
list: linked list of TFMs

struct tipc_aead¶: TIPC AEAD key structure

Definition

struct tipc_aead {
#define TIPC_AEAD_HINT_LEN (5);
  struct tipc_tfm * __percpu *tfm_entry;
  struct tipc_crypto *crypto;
  struct tipc_aead *cloned;
  atomic_t users;
  u32 salt;
  u8 authsize;
  u8 mode;
  char hint[2 * TIPC_AEAD_HINT_LEN + 1];
  struct rcu_head rcu;
  struct tipc_aead_key *key;
  u16 gen;
  atomic64_t seqno ;
  refcount_t refcnt ;
};

Members

tfm_entry: per-cpu pointer to one entry in TFM list
crypto: TIPC crypto owns this key
cloned: reference to the source key in case cloning
users: the number of the key users (TX/RX)
salt: the key’s SALT value
authsize: authentication tag size (max = 16)
mode: crypto mode is applied to the key
hint: a hint for user key
rcu: struct rcu_head
key: the aead key
gen: the key’s generation
seqno: the key seqno (cluster scope)
refcnt: the key reference counter

struct tipc_crypto_stats¶: TIPC Crypto statistics

Definition

struct tipc_crypto_stats {
  unsigned int stat[MAX_STATS];
};

Members

stat: array of crypto statistics

struct tipc_crypto¶: TIPC TX/RX crypto structure

Definition

struct tipc_crypto {
  struct net *net;
  struct tipc_node *node;
  struct tipc_aead __rcu *aead[KEY_MAX + 1];
  atomic_t peer_rx_active;
  u16 key_gen;
  struct tipc_key key;
  u8 skey_mode;
  struct tipc_aead_key *skey;
  struct workqueue_struct *wq;
  struct delayed_work work;
#define KEY_DISTR_SCHED         1;
#define KEY_DISTR_COMPL         2;
  atomic_t key_distr;
  u32 rekeying_intv;
  struct tipc_crypto_stats __percpu *stats;
  char name[48];
  atomic64_t sndnxt ;
  unsigned long timer1;
  unsigned long timer2;
  union {
    struct {
      u8 working:1;
      u8 key_master:1;
      u8 legacy_user:1;
      u8 nokey: 1;
    };
    u8 flags;
  };
  spinlock_t lock;
};

Members

net: struct net
node: TIPC node (RX)
aead: array of pointers to AEAD keys for encryption/decryption
peer_rx_active: replicated peer RX active key index
key_gen: TX/RX key generation
key: the key states
skey_mode: session key’s mode
skey: received session key
wq: common workqueue on TX crypto
work: delayed work sched for TX/RX
key_distr: key distributing state
rekeying_intv: rekeying interval (in minutes)
stats: the crypto statistics
name: the crypto name
sndnxt: the per-peer sndnxt (TX)
timer1: general timer 1 (jiffies)
timer2: general timer 2 (jiffies)
{unnamed_union}: anonymous
{unnamed_struct}: anonymous
working: the crypto is working or not
key_master: flag indicates if master key exists
legacy_user: flag indicates if a peer joins w/o master key (for bwd comp.)
nokey: no key indication
flags: combined flags field
lock: tipc_key lock

int tipc_aead_key_validate(struct tipc_aead_key *ukey, struct genl_info *info)¶: Validate a AEAD user key

Parameters

struct tipc_aead_key *ukey: pointer to user key data
struct genl_info *info: netlink info pointer

int tipc_aead_key_generate(struct tipc_aead_key *skey)¶: Generate new session key

Parameters

struct tipc_aead_key *skey: input/output key with new content

Return

0 in case of success, otherwise < 0

void tipc_aead_free(struct rcu_head *rp)¶: Release AEAD key incl. all the TFMs in the list

Parameters

struct rcu_head *rp: rcu head pointer

struct crypto_aead * tipc_aead_tfm_next(struct tipc_aead *aead)¶: Move TFM entry to the next one in list and return it

Parameters

struct tipc_aead *aead: the AEAD key pointer

int tipc_aead_init(struct tipc_aead **aead, struct tipc_aead_key *ukey, u8 mode)¶: Initiate TIPC AEAD

Parameters

struct tipc_aead **aead: returned new TIPC AEAD key handle pointer
struct tipc_aead_key *ukey: pointer to user key data
u8 mode: the key mode

Description

Allocate a (list of) new cipher transformation (TFM) with the specific user key data if valid. The number of the allocated TFMs can be set via the sysfs “net/tipc/max_tfms” first. Also, all the other AEAD data are also initialized.

Return

0 if the initiation is successful, otherwise: < 0

int tipc_aead_clone(struct tipc_aead **dst, struct tipc_aead *src)¶: Clone a TIPC AEAD key

Parameters

struct tipc_aead **dst: dest key for the cloning
struct tipc_aead *src: source key to clone from

Description

Make a “copy” of the source AEAD key data to the dest, the TFMs list is common for the keys. A reference to the source is hold in the “cloned” pointer for the later freeing purposes.

Note

this must be done in cluster-key mode only!

Return

0 in case of success, otherwise < 0

void * tipc_aead_mem_alloc(struct crypto_aead *tfm, unsigned int crypto_ctx_size, u8 **iv, struct aead_request **req, struct scatterlist **sg, int nsg)¶: Allocate memory for AEAD request operations

Parameters

struct crypto_aead *tfm: cipher handle to be registered with the request
unsigned int crypto_ctx_size: size of crypto context for callback
u8 **iv: returned pointer to IV data
struct aead_request **req: returned pointer to AEAD request data
struct scatterlist **sg: returned pointer to SG lists
int nsg: number of SG lists to be allocated

Description

Allocate memory to store the crypto context data, AEAD request, IV and SG lists, the memory layout is as follows: crypto_ctx || iv || aead_req || sg[]

Return

the pointer to the memory areas in case of success, otherwise NULL

int tipc_aead_encrypt(struct tipc_aead *aead, struct sk_buff *skb, struct tipc_bearer *b, struct tipc_media_addr *dst, struct tipc_node *__dnode)¶: Encrypt a message

Parameters

struct tipc_aead *aead: TIPC AEAD key for the message encryption
struct sk_buff *skb: the input/output skb
struct tipc_bearer *b: TIPC bearer where the message will be delivered after the encryption
struct tipc_media_addr *dst: the destination media address
struct tipc_node *__dnode: TIPC dest node if “known”

Return

0 : if the encryption has completed
-EINPROGRESS/-EBUSY : if a callback will be performed
< 0 : the encryption has failed

int tipc_aead_decrypt(struct net *net, struct tipc_aead *aead, struct sk_buff *skb, struct tipc_bearer *b)¶: Decrypt an encrypted message

Parameters

struct net *net: struct net
struct tipc_aead *aead: TIPC AEAD for the message decryption
struct sk_buff *skb: the input/output skb
struct tipc_bearer *b: TIPC bearer where the message has been received

Return

0 : if the decryption has completed
-EINPROGRESS/-EBUSY : if a callback will be performed
< 0 : the decryption has failed

bool tipc_ehdr_validate(struct sk_buff *skb)¶: Validate an encryption message

Parameters

struct sk_buff *skb: the message buffer

Return

“true” if this is a valid encryption message, otherwise “false”

int tipc_ehdr_build(struct net *net, struct tipc_aead *aead, u8 tx_key, struct sk_buff *skb, struct tipc_crypto *__rx)¶: Build TIPC encryption message header

Parameters

struct net *net: struct net
struct tipc_aead *aead: TX AEAD key to be used for the message encryption
u8 tx_key: key id used for the message encryption
struct sk_buff *skb: input/output message skb
struct tipc_crypto *__rx: RX crypto handle if dest is “known”

Return

the header size if the building is successful, otherwise < 0

int tipc_crypto_key_init(struct tipc_crypto *c, struct tipc_aead_key *ukey, u8 mode, bool master_key)¶: Initiate a new user / AEAD key

Parameters

struct tipc_crypto *c: TIPC crypto to which new key is attached
struct tipc_aead_key *ukey: the user key
u8 mode: the key mode (CLUSTER_KEY or PER_NODE_KEY)
bool master_key: specify this is a cluster master key

Description

A new TIPC AEAD key will be allocated and initiated with the specified user key, then attached to the TIPC crypto.

Return

new key id in case of success, otherwise: < 0

int tipc_crypto_key_attach(struct tipc_crypto *c, struct tipc_aead *aead, u8 pos, bool master_key)¶: Attach a new AEAD key to TIPC crypto

Parameters

struct tipc_crypto *c: TIPC crypto to which the new AEAD key is attached
struct tipc_aead *aead: the new AEAD key pointer
u8 pos: desired slot in the crypto key array, = 0 if any!
bool master_key: specify this is a cluster master key

Return

new key id in case of success, otherwise: -EBUSY

bool tipc_crypto_key_try_align(struct tipc_crypto *rx, u8 new_pending)¶: Align RX keys if possible

Parameters

struct tipc_crypto *rx: RX crypto handle
u8 new_pending: new pending slot if aligned (= TX key from peer)

Description

Peer has used an unknown key slot, this only happens when peer has left and rejoned, or we are newcomer. That means, there must be no active key but a pending key at unaligned slot. If so, we try to move the pending key to the new slot.

Note

A potential passive key can exist, it will be shifted correspondingly!

Return

“true” if key is successfully aligned, otherwise “false”

struct tipc_aead * tipc_crypto_key_pick_tx(struct tipc_crypto *tx, struct tipc_crypto *rx, struct sk_buff *skb, u8 tx_key)¶: Pick one TX key for message decryption

Parameters

struct tipc_crypto *tx: TX crypto handle
struct tipc_crypto *rx: RX crypto handle (can be NULL)
struct sk_buff *skb: the message skb which will be decrypted later
u8 tx_key: peer TX key id

Description

This function looks up the existing TX keys and pick one which is suitable for the message decryption, that must be a cluster key and not used before on the same message (i.e. recursive).

Return

the TX AEAD key handle in case of success, otherwise NULL

void tipc_crypto_key_synch(struct tipc_crypto *rx, struct sk_buff *skb)¶: Synch own key data according to peer key status

Parameters

struct tipc_crypto *rx: RX crypto handle
struct sk_buff *skb: TIPCv2 message buffer (incl. the ehdr from peer)

Description

This function updates the peer node related data as the peer RX active key has changed, so the number of TX keys’ users on this node are increased and decreased correspondingly.

It also considers if peer has no key, then we need to make own master key (if any) taking over i.e. starting grace period and also trigger key distributing process.

The “per-peer” sndnxt is also reset when the peer key has switched.

int tipc_crypto_xmit(struct net *net, struct sk_buff **skb, struct tipc_bearer *b, struct tipc_media_addr *dst, struct tipc_node *__dnode)¶: Build & encrypt TIPC message for xmit

Parameters

struct net *net: struct net
struct sk_buff **skb: input/output message skb pointer
struct tipc_bearer *b: bearer used for xmit later
struct tipc_media_addr *dst: destination media address
struct tipc_node *__dnode: destination node for reference if any

Description

First, build an encryption message header on the top of the message, then encrypt the original TIPC message by using the pending, master or active key with this preference order. If the encryption is successful, the encrypted skb is returned directly or via the callback. Otherwise, the skb is freed!

Return

0 : the encryption has succeeded (or no encryption)
-EINPROGRESS/-EBUSY : the encryption is ongoing, a callback will be made
-ENOKEK

: the encryption has failed due to no key
-EKEYREVOKED

: the encryption has failed due to key revoked
-ENOMEM

: the encryption has failed due to no memory
< 0 : the encryption has failed due to other reasons

int tipc_crypto_rcv(struct net *net, struct tipc_crypto *rx, struct sk_buff **skb, struct tipc_bearer *b)¶: Decrypt an encrypted TIPC message from peer

Parameters

struct net *net: struct net
struct tipc_crypto *rx: RX crypto handle
struct sk_buff **skb: input/output message skb pointer
struct tipc_bearer *b: bearer where the message has been received

Description

If the decryption is successful, the decrypted skb is returned directly or as the callback, the encryption header and auth tag will be trimed out before forwarding to tipc_rcv() via the tipc_crypto_rcv_complete(). Otherwise, the skb will be freed!

Note

RX key(s) can be re-aligned, or in case of no key suitable, TX cluster key(s) can be taken for decryption (- recursive).

Return

0 : the decryption has successfully completed
-EINPROGRESS/-EBUSY : the decryption is ongoing, a callback will be made
-ENOKEY

: the decryption has failed due to no key
-EBADMSG

: the decryption has failed due to bad message
-ENOMEM

: the decryption has failed due to no memory
< 0 : the decryption has failed due to other reasons

void tipc_crypto_msg_rcv(struct net *net, struct sk_buff *skb)¶: Common ‘MSG_CRYPTO’ processing point

Parameters

struct net *net: the struct net
struct sk_buff *skb: the receiving message buffer

int tipc_crypto_key_distr(struct tipc_crypto *tx, u8 key, struct tipc_node *dest)¶: Distribute a TX key

Parameters

struct tipc_crypto *tx: the TX crypto
u8 key: the key’s index
struct tipc_node *dest: the destination tipc node, = NULL if distributing to all nodes

Return

0 in case of success, otherwise < 0

int tipc_crypto_key_xmit(struct net *net, struct tipc_aead_key *skey, u16 gen, u8 mode, u32 dnode)¶: Send a session key

Parameters

struct net *net: the struct net
struct tipc_aead_key *skey: the session key to be sent
u16 gen: the key’s generation
u8 mode: the key’s mode
u32 dnode: the destination node address, = 0 if broadcasting to all nodes

Description

The session key ‘skey’ is packed in a TIPC v2 ‘MSG_CRYPTO/KEY_DISTR_MSG’ as its data section, then xmit-ed through the uc/bc link.

Return

0 in case of success, otherwise < 0

bool tipc_crypto_key_rcv(struct tipc_crypto *rx, struct tipc_msg *hdr)¶: Receive a session key

Parameters

struct tipc_crypto *rx: the RX crypto
struct tipc_msg *hdr: the TIPC v2 message incl. the receiving session key in its data

Description

This function retrieves the session key in the message from peer, then schedules a RX work to attach the key to the corresponding RX crypto.

Return

“true” if the key has been scheduled for attaching, otherwise “false”.

void tipc_crypto_work_rx(struct work_struct *work)¶: Scheduled RX works handler

Parameters

struct work_struct *work: the struct RX work

Description

The function processes the previous scheduled works i.e. distributing TX key or attaching a received session key on RX crypto.

void tipc_crypto_rekeying_sched(struct tipc_crypto *tx, bool changed, u32 new_intv)¶: (Re)schedule rekeying w/o new interval

Parameters

struct tipc_crypto *tx: TX crypto
bool changed: if the rekeying needs to be rescheduled with new interval
u32 new_intv: new rekeying interval (when “changed” = true)

void tipc_crypto_work_tx(struct work_struct *work)¶: Scheduled TX works handler

Parameters

struct work_struct *work: the struct TX work

Description

The function processes the previous scheduled work, i.e. key rekeying, by generating a new session key based on current one, then attaching it to the TX crypto and finally distributing it to peers. It also re-schedules the rekeying if needed.

TIPC Discoverer Interfaces¶

struct tipc_discoverer¶: information about an ongoing link setup request

Definition

struct tipc_discoverer {
  u32 bearer_id;
  struct tipc_media_addr dest;
  struct net *net;
  u32 domain;
  int num_nodes;
  spinlock_t lock;
  struct sk_buff *skb;
  struct timer_list timer;
  unsigned long timer_intv;
};

Members

bearer_id: identity of bearer issuing requests
dest: destination address for request messages
net: network namespace instance
domain: network domain to which links can be established
num_nodes: number of nodes currently discovered (i.e. with an active link)
lock: spinlock for controlling access to requests
skb: request message to be (repeatedly) sent
timer: timer governing period between requests
timer_intv: current interval between requests (in ms)

void tipc_disc_init_msg(struct net *net, struct sk_buff *skb, u32 mtyp, struct tipc_bearer *b)¶: initialize a link setup message

Parameters

struct net *net: the applicable net namespace
struct sk_buff *skb: buffer containing message
u32 mtyp: message type (request or response)
struct tipc_bearer *b: ptr to bearer issuing message

void disc_dupl_alert(struct tipc_bearer *b, u32 node_addr, struct tipc_media_addr *media_addr)¶: issue node address duplication alert

Parameters

struct tipc_bearer *b: pointer to bearer detecting duplication
u32 node_addr: duplicated node address
struct tipc_media_addr *media_addr: media address advertised by duplicated node

void tipc_disc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)¶: handle incoming discovery message (request or response)

Parameters

struct net *net: applicable net namespace
struct sk_buff *skb: buffer containing message
struct tipc_bearer *b: bearer that message arrived on

int tipc_disc_create(struct net *net, struct tipc_bearer *b, struct tipc_media_addr *dest, struct sk_buff **skb)¶: create object to send periodic link setup requests

Parameters

struct net *net: the applicable net namespace
struct tipc_bearer *b: ptr to bearer issuing requests
struct tipc_media_addr *dest: destination address for request messages
struct sk_buff **skb: pointer to created frame

Return

0 if successful, otherwise -errno.

void tipc_disc_delete(struct tipc_discoverer *d)¶: destroy object sending periodic link setup requests

Parameters

struct tipc_discoverer *d: ptr to link dest structure

void tipc_disc_reset(struct net *net, struct tipc_bearer *b)¶: reset object to send periodic link setup requests

Parameters

struct net *net: the applicable net namespace
struct tipc_bearer *b: ptr to bearer issuing requests

TIPC Link Interfaces¶

Error

kernel-doc missing

TIPC msg Interfaces¶

struct sk_buff * tipc_buf_acquire(u32 size, gfp_t gfp)¶: creates a TIPC message buffer

Parameters

u32 size: message size (including TIPC header)
gfp_t gfp: memory allocation flags

Return

a new buffer with data pointers set to the specified size.

NOTE

Headroom is reserved to allow prepending of a data link header. There may also be unrequested tailroom present at the buffer’s end.

int tipc_msg_append(struct tipc_msg *_hdr, struct msghdr *m, int dlen, int mss, struct sk_buff_head *txq)¶: Append data to tail of an existing buffer queue

Parameters

struct tipc_msg *_hdr: header to be used
struct msghdr *m: the data to be appended
int dlen: size of data to be appended
int mss: max allowable size of buffer
struct sk_buff_head *txq: queue to append to

Return

the number of 1k blocks appended or errno value

int tipc_msg_fragment(struct sk_buff *skb, const struct tipc_msg *hdr, int pktmax, struct sk_buff_head *frags)¶: build a fragment skb list for TIPC message

Parameters

struct sk_buff *skb: TIPC message skb
const struct tipc_msg *hdr: internal msg header to be put on the top of the fragments
int pktmax: max size of a fragment incl. the header
struct sk_buff_head *frags: returned fragment skb list

Return

0 if the fragmentation is successful, otherwise: -EINVAL or -ENOMEM

int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m, int offset, int dsz, int pktmax, struct sk_buff_head *list)¶: create buffer chain containing specified header and data

Parameters

struct tipc_msg *mhdr: Message header, to be prepended to data
struct msghdr *m: User message
int offset: buffer offset for fragmented messages (FIXME)
int dsz: Total length of user data
int pktmax: Max packet size that can be used
struct sk_buff_head *list: Buffer or chain of buffers to be returned to caller

Description

Note that the recursive call we are making here is safe, since it can logically go only one further level down.

Return

message data size or errno: -ENOMEM, -EFAULT

bool tipc_msg_bundle(struct sk_buff *bskb, struct tipc_msg *msg, u32 max)¶: Append contents of a buffer to tail of an existing one

Parameters

struct sk_buff *bskb: the bundle buffer to append to
struct tipc_msg *msg: message to be appended
u32 max: max allowable size for the bundle buffer

Return

“true” if bundling has been performed, otherwise “false”

bool tipc_msg_try_bundle(struct sk_buff *tskb, struct sk_buff **skb, u32 mss, u32 dnode, bool *new_bundle)¶: Try to bundle a new message to the last one

Parameters

struct sk_buff *tskb: the last/target message to which the new one will be appended
struct sk_buff **skb: the new message skb pointer
u32 mss: max message size (header inclusive)
u32 dnode: destination node for the message
bool *new_bundle: if this call made a new bundle or not

Return

“true” if the new message skb is potential for bundling this time or later, in the case a bundling has been done this time, the skb is consumed (the skb pointer = NULL). Otherwise, “false” if the skb cannot be bundled at all.

bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)¶: extract bundled inner packet from buffer

Parameters

struct sk_buff *skb: buffer to be extracted from.
struct sk_buff **iskb: extracted inner buffer, to be returned
int *pos: position in outer message of msg to be extracted. Returns position of next msg. Consumes outer buffer when last packet extracted

Return

true when there is an extracted buffer, otherwise false

bool tipc_msg_reverse(u32 own_node, struct sk_buff **skb, int err)¶: swap source and destination addresses and add error code

Parameters

u32 own_node: originating node id for reversed message
struct sk_buff **skb: buffer containing message to be reversed; will be consumed
int err: error code to be set in message, if any Replaces consumed buffer with new one when successful

Return

true if success, otherwise false

bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, int *err)¶: try to find new destination for named message

Parameters

struct net *net: pointer to associated network namespace
struct sk_buff *skb: the buffer containing the message.
int *err: error code to be used by caller if lookup fails Does not consume buffer

Return

true if a destination is found, false otherwise

TIPC Name Interfaces¶

struct service_range¶: container for all bindings of a service range

Definition

struct service_range {
  u32 lower;
  u32 upper;
  struct rb_node tree_node;
  u32 max;
  struct list_head local_publ;
  struct list_head all_publ;
};

Members

lower: service range lower bound
upper: service range upper bound
tree_node: member of service range RB tree
max: largest ‘upper’ in this node subtree
local_publ: list of identical publications made from this node Used by closest_first lookup and multicast lookup algorithm
all_publ: all publications identical to this one, whatever node and scope Used by round-robin lookup algorithm

struct tipc_service¶: container for all published instances of a service type

Definition

struct tipc_service {
  u32 type;
  u32 publ_cnt;
  struct rb_root ranges;
  struct hlist_node service_list;
  struct list_head subscriptions;
  spinlock_t lock;
  struct rcu_head rcu;
};

Members

type: 32 bit ‘type’ value for service
publ_cnt: increasing counter for publications in this service
ranges: rb tree containing all service ranges for this service
service_list: links to adjacent name ranges in hash chain
subscriptions: list of subscriptions for this service type
lock: spinlock controlling access to pertaining service ranges/publications
rcu: RCU callback head used for deferred freeing

service_range_foreach_match(sr, sc, start, end)¶: iterate over tipc service rbtree for each range match

Parameters

sr: the service range pointer as a loop cursor
sc: the pointer to tipc service which holds the service range rbtree
start: beginning of the search range (end >= start) for matching
end: end of the search range (end >= start) for matching

struct service_range * service_range_match_first(struct rb_node *n, u32 start, u32 end)¶: find first service range matching a range

Parameters

struct rb_node *n: the root node of service range rbtree for searching
u32 start: beginning of the search range (end >= start) for matching
u32 end: end of the search range (end >= start) for matching

Return

the leftmost service range node in the rbtree that overlaps the specific range if any. Otherwise, returns NULL.

struct service_range * service_range_match_next(struct rb_node *n, u32 start, u32 end)¶: find next service range matching a range

Parameters

struct rb_node *n: a node in service range rbtree from which the searching starts
u32 start: beginning of the search range (end >= start) for matching
u32 end: end of the search range (end >= start) for matching

Return

the next service range node to the given node in the rbtree that overlaps the specific range if any. Otherwise, returns NULL.

struct publication * tipc_publ_create(struct tipc_uaddr *ua, struct tipc_socket_addr *sk, u32 key)¶: create a publication structure

Parameters

struct tipc_uaddr *ua: the service range the user is binding to
struct tipc_socket_addr *sk: the address of the socket that is bound
u32 key: publication key

struct tipc_service * tipc_service_create(struct net *net, struct tipc_uaddr *ua)¶: create a service structure for the specified ‘type’

Parameters

struct net *net: network namespace
struct tipc_uaddr *ua: address representing the service to be bound

Description

Allocates a single range structure and sets it to all 0’s.

struct publication * tipc_service_remove_publ(struct service_range *r, struct tipc_socket_addr *sk, u32 key)¶: remove a publication from a service

Parameters

struct service_range *r: service_range to remove publication from
struct tipc_socket_addr *sk: address publishing socket
u32 key: target publication key

void tipc_service_subscribe(struct tipc_service *service, struct tipc_subscription *sub)¶: attach a subscription, and optionally issue the prescribed number of events if there is any service range overlapping with the requested range

Parameters

struct tipc_service *service: the tipc_service to attach the sub to
struct tipc_subscription *sub: the subscription to attach

bool tipc_nametbl_lookup_anycast(struct net *net, struct tipc_uaddr *ua, struct tipc_socket_addr *sk)¶: perform service instance to socket translation

Parameters

struct net *net: network namespace
struct tipc_uaddr *ua: service address to look up
struct tipc_socket_addr *sk: address to socket we want to find

Description

On entry, a non-zero ‘sk->node’ indicates the node where we want lookup to be performed, which may not be this one.

On exit:

If lookup is deferred to another node, leave ‘sk->node’ unchanged and return ‘true’.
If lookup is successful, set the ‘sk->node’ and ‘sk->ref’ (== portid) which represent the bound socket and return ‘true’.
If lookup fails, return ‘false’

Note that for legacy users (node configured with Z.C.N address format) the ‘closest-first’ lookup algorithm must be maintained, i.e., if sk.node is 0 we must look in the local binding list first

void tipc_nametbl_withdraw(struct net *net, struct tipc_uaddr *ua, struct tipc_socket_addr *sk, u32 key)¶: withdraw a service binding

Parameters

struct net *net: network namespace
struct tipc_uaddr *ua: service address/range being unbound
struct tipc_socket_addr *sk: address of the socket being unbound from
u32 key: target publication key

bool tipc_nametbl_subscribe(struct tipc_subscription *sub)¶: add a subscription object to the name table

Parameters

struct tipc_subscription *sub: subscription to add

void tipc_nametbl_unsubscribe(struct tipc_subscription *sub)¶: remove a subscription object from name table

Parameters

struct tipc_subscription *sub: subscription to remove

void tipc_service_delete(struct net *net, struct tipc_service *sc)¶: purge all publications for a service and delete it

Parameters

struct net *net: the associated network namespace
struct tipc_service *sc: tipc_service to delete

void publ_to_item(struct distr_item *i, struct publication *p)¶: add publication info to a publication message

Parameters

struct distr_item *i: location of item in the message
struct publication *p: publication info

struct sk_buff * named_prepare_buf(struct net *net, u32 type, u32 size, u32 dest)¶: allocate & initialize a publication message

Parameters

struct net *net: the associated network namespace
u32 type: message type
u32 size: payload size
u32 dest: destination node

Description

The buffer returned is of size INT_H_SIZE + payload size

struct sk_buff * tipc_named_publish(struct net *net, struct publication *p)¶: tell other nodes about a new publication by this node

Parameters

struct net *net: the associated network namespace
struct publication *p: the new publication

struct sk_buff * tipc_named_withdraw(struct net *net, struct publication *p)¶: tell other nodes about a withdrawn publication by this node

Parameters

struct net *net: the associated network namespace
struct publication *p: the withdrawn publication

void named_distribute(struct net *net, struct sk_buff_head *list, u32 dnode, struct list_head *pls, u16 seqno)¶: prepare name info for bulk distribution to another node

Parameters

struct net *net: the associated network namespace
struct sk_buff_head *list: list of messages (buffers) to be returned from this function
u32 dnode: node to be updated
struct list_head *pls: linked list of publication items to be packed into buffer chain
u16 seqno: sequence number for this message

void tipc_named_node_up(struct net *net, u32 dnode, u16 capabilities)¶: tell specified node about all publications by this node

Parameters

struct net *net: the associated network namespace
u32 dnode: destination node
u16 capabilities: peer node’s capabilities

void tipc_publ_purge(struct net *net, struct publication *p, u32 addr)¶: remove publication associated with a failed node

Parameters

struct net *net: the associated network namespace
struct publication *p: the publication to remove
u32 addr: failed node’s address

Description

Invoked for each publication issued by a newly failed node. Removes publication structure from name table & deletes it.

bool tipc_update_nametbl(struct net *net, struct distr_item *i, u32 node, u32 dtype)¶: try to process a nametable update and notify subscribers

Parameters

struct net *net: the associated network namespace
struct distr_item *i: location of item in the message
u32 node: node address
u32 dtype: name distributor message type

Description

tipc_nametbl_lock must be held.

Return

the publication item if successful, otherwise NULL.

void tipc_named_rcv(struct net *net, struct sk_buff_head *namedq, u16 *rcv_nxt, bool *open)¶: process name table update messages sent by another node

Parameters

struct net *net: the associated network namespace
struct sk_buff_head *namedq: queue to receive from
u16 *rcv_nxt: store last received seqno here
bool *open: last bulk msg was received (FIXME)

void tipc_named_reinit(struct net *net)¶: re-initialize local publications

Parameters

struct net *net: the associated network namespace

Description

This routine is called whenever TIPC networking is enabled. All name table entries published by this node are updated to reflect the node’s new network address.

TIPC Node Management Interfaces¶

Error

kernel-doc missing

TIPC Socket Interfaces¶

Error

kernel-doc missing

TIPC Network Topology Interfaces¶

bool tipc_sub_check_overlap(struct tipc_service_range *subscribed, struct tipc_service_range *found)¶: test for subscription overlap with the given values

Parameters

struct tipc_service_range *subscribed: the service range subscribed for
struct tipc_service_range *found: the service range we are checking for match

Description

Returns true if there is overlap, otherwise false.

TIPC Server Interfaces¶

struct tipc_topsrv¶: TIPC server structure

Definition

struct tipc_topsrv {
  struct idr conn_idr;
  spinlock_t idr_lock;
  int idr_in_use;
  struct net *net;
  struct work_struct awork;
  struct workqueue_struct *rcv_wq;
  struct workqueue_struct *send_wq;
  struct socket *listener;
  char name[TIPC_SERVER_NAME_LEN];
};

Members

conn_idr: identifier set of connection
idr_lock: protect the connection identifier set
idr_in_use: amount of allocated identifier entry
net: network namspace instance
awork: accept work item
rcv_wq: receive workqueue
send_wq: send workqueue
listener: topsrv listener socket
name: server name

struct tipc_conn¶: TIPC connection structure

Definition

struct tipc_conn {
  struct kref kref;
  int conid;
  struct socket *sock;
  unsigned long flags;
  struct tipc_topsrv *server;
  struct list_head sub_list;
  spinlock_t sub_lock;
  struct work_struct rwork;
  struct list_head outqueue;
  spinlock_t outqueue_lock;
  struct work_struct swork;
};

Members

kref: reference counter to connection object
conid: connection identifier
sock: socket handler associated with connection
flags: indicates connection state
server: pointer to connected server
sub_list: lsit to all pertaing subscriptions
sub_lock: lock protecting the subscription list
rwork: receive work item
outqueue: pointer to first outbound message in queue
outqueue_lock: control access to the outqueue
swork: send work item

TIPC Trace Interfaces¶

int tipc_skb_dump(struct sk_buff *skb, bool more, char *buf)¶: dump TIPC skb data

Parameters

struct sk_buff *skb: skb to be dumped
bool more: dump more? - false: dump only tipc msg data - true: dump kernel-related skb data and tipc cb[] array as well
char *buf: returned buffer of dump data in format

int tipc_list_dump(struct sk_buff_head *list, bool more, char *buf)¶: dump TIPC skb list/queue

Parameters

struct sk_buff_head *list: list of skbs to be dumped
bool more: dump more? - false: dump only the head & tail skbs - true: dump the first & last 5 skbs
char *buf: returned buffer of dump data in format