From 556284a10e482027f741f9afe6cbaa1b4e2207f8 Mon Sep 17 00:00:00 2001 From: Matthias Schiffer Date: Tue, 27 May 2014 04:09:15 +0200 Subject: peer: completely document peer.h and peer.c --- src/peer.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) (limited to 'src/peer.c') diff --git a/src/peer.c b/src/peer.c index 7a3029d..63e0b2f 100644 --- a/src/peer.c +++ b/src/peer.c @@ -23,6 +23,11 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ +/** + \file peer.c + + Implementations of functions for peer management +*/ #include "peer.h" #include "peer_hashtable.h" @@ -32,6 +37,7 @@ #include +/** Adds peer-specific fields to \e env */ void fastd_peer_set_shell_env(fastd_shell_env_t *env, const fastd_peer_t *peer, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *peer_addr) { /* both INET6_ADDRSTRLEN and IFNAMESIZE already include space for the zero termination, so there is no need to add space for the '%' here. */ char buf[INET6_ADDRSTRLEN+IF_NAMESIZE]; @@ -101,6 +107,7 @@ void fastd_peer_set_shell_env(fastd_shell_env_t *env, const fastd_peer_t *peer, conf.protocol->set_shell_env(env, peer); } +/** Executes a shell command, providing peer-specific enviroment fields */ void fastd_peer_exec_shell_command(const fastd_shell_command_t *command, const fastd_peer_t *peer, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *peer_addr) { fastd_shell_env_t *env = fastd_shell_env_alloc(); fastd_peer_set_shell_env(env, peer, local_addr, peer_addr); @@ -108,14 +115,17 @@ void fastd_peer_exec_shell_command(const fastd_shell_command_t *command, const f fastd_shell_env_free(env); } +/** Executes the on-establish command for a peer */ static inline void on_establish(const fastd_peer_t *peer) { fastd_peer_exec_shell_command(&conf.on_establish, peer, &peer->local_address, &peer->address); } +/** Executes the on-disestablish command for a peer */ static inline void on_disestablish(const fastd_peer_t *peer) { fastd_peer_exec_shell_command(&conf.on_disestablish, peer, &peer->local_address, &peer->address); } +/** Compares two peers by their peer ID */ static int peer_id_cmp(fastd_peer_t *const *a, fastd_peer_t *const *b) { if ((*a)->id == (*b)->id) return 0; @@ -125,6 +135,7 @@ static int peer_id_cmp(fastd_peer_t *const *a, fastd_peer_t *const *b) { return 1; } +/** Finds the entry for a peer with a specified ID in the array \e ctx.peers */ static fastd_peer_t** peer_p_find_by_id(uint64_t id) { fastd_peer_t key = {.id = id}; fastd_peer_t *const keyp = &key; @@ -132,6 +143,7 @@ static fastd_peer_t** peer_p_find_by_id(uint64_t id) { return VECTOR_BSEARCH(&keyp, ctx.peers, peer_id_cmp); } +/** Finds the index of a peer with a specified ID in the array \e ctx.peers */ static size_t peer_index_find_by_id(uint64_t id) { fastd_peer_t **ret = peer_p_find_by_id(id); @@ -142,10 +154,12 @@ static size_t peer_index_find_by_id(uint64_t id) { } +/** Finds the index of a peer in the array \e ctx.peers */ static inline size_t peer_index(fastd_peer_t *peer) { return peer_index_find_by_id(peer->id); } +/** Finds a peer with a specified ID */ fastd_peer_t* fastd_peer_find_by_id(uint64_t id) { fastd_peer_t **ret = peer_p_find_by_id(id); @@ -156,6 +170,7 @@ fastd_peer_t* fastd_peer_find_by_id(uint64_t id) { } +/** Closes and frees the dynamic socket of the peer with a specified ID */ static void free_socket_by_id(size_t i) { fastd_peer_t *peer = VECTOR_INDEX(ctx.peers, i); @@ -177,10 +192,12 @@ static void free_socket_by_id(size_t i) { } } +/** Closes and frees a peer's dynamic socket */ static inline void free_socket(fastd_peer_t *peer) { free_socket_by_id(peer_index(peer)); } +/** Checks if a peer group has any contraints which might cause connection attempts to be rejected */ static inline bool has_group_config_constraints(const fastd_peer_group_t *group) { for (; group; group = group->parent) { if (group->max_connections >= 0) @@ -190,6 +207,12 @@ static inline bool has_group_config_constraints(const fastd_peer_group_t *group) return false; } +/** + Resets a peer's socket + + If the peer's old socket is dynamic, it is closed. Then either a new dynamic socket is opened + or a default socket is used. +*/ void fastd_peer_reset_socket(fastd_peer_t *peer) { size_t i = peer_index(peer); @@ -226,6 +249,12 @@ void fastd_peer_reset_socket(fastd_peer_t *peer) { fastd_poll_set_fd_peer(i); } +/** + Schedules a handshake after the given delay + + @param peer the peer + @param delay the delay in milliseconds +*/ void fastd_peer_schedule_handshake(fastd_peer_t *peer, int delay) { fastd_peer_unschedule_handshake(peer); @@ -250,6 +279,7 @@ void fastd_peer_schedule_handshake(fastd_peer_t *peer, int delay) { fastd_dlist_insert(list, &peer->handshake_entry); } +/** Checks if the peer group \e group1 lies in \e group2 */ static inline bool is_group_in(const fastd_peer_group_t *group1, const fastd_peer_group_t *group2) { while (group1) { if (group1 == group2) @@ -261,10 +291,18 @@ static inline bool is_group_in(const fastd_peer_group_t *group1, const fastd_pee return false; } +/** Checks if a peer lies in a peer group */ static bool is_peer_in_group(const fastd_peer_t *peer, const fastd_peer_group_t *group) { return is_group_in(fastd_peer_get_group(peer), group); } +/** + Resets a peer (internal function) + + Disestablished the current connection with the peer (if any) and drops any scheduled handshake. + + After a call to reset_peer a peer must be deleted by delete_peer or re-initialized by setup_peer. +*/ static void reset_peer(fastd_peer_t *peer) { if (fastd_peer_is_established(peer)) on_disestablish(peer); @@ -290,6 +328,13 @@ static void reset_peer(fastd_peer_t *peer) { fastd_peer_unschedule_handshake(peer); } +/** + Starts the first handshake with a newly setup peer + + If a peer group has a peer limit the handshakes will be delayed between 0 and 3 seconds + make the choice of peers random (it will be biased by the latency, which might or might not be + what a user wants) +*/ static void init_handshake(fastd_peer_t *peer) { unsigned delay = 0; if (has_group_config_constraints(fastd_peer_get_group(peer))) @@ -301,6 +346,7 @@ static void init_handshake(fastd_peer_t *peer) { fastd_peer_schedule_handshake(peer, delay); } +/** Handles an asynchronous DNS resolve response */ void fastd_peer_handle_resolve(fastd_peer_t *peer, fastd_remote_t *remote, size_t n_addresses, const fastd_peer_address_t *addresses) { free(remote->addresses); remote->addresses = malloc(n_addresses*sizeof(fastd_peer_address_t)); @@ -313,6 +359,7 @@ void fastd_peer_handle_resolve(fastd_peer_t *peer, fastd_remote_t *remote, size_ init_handshake(peer); } +/** Initializes a peer */ static void setup_peer(fastd_peer_t *peer) { peer->address.sa.sa_family = AF_UNSPEC; peer->local_address.sa.sa_family = AF_UNSPEC; @@ -355,6 +402,7 @@ static void setup_peer(fastd_peer_t *peer) { } } +/** Frees a peer */ static void delete_peer(fastd_peer_t *peer) { pr_debug("deleting peer %P", peer); @@ -378,6 +426,7 @@ static void delete_peer(fastd_peer_t *peer) { } +/** Allocates a new peer config */ fastd_peer_config_t* fastd_peer_config_new(void) { fastd_peer_config_t *peer = calloc(1, sizeof(fastd_peer_config_t)); @@ -389,6 +438,7 @@ fastd_peer_config_t* fastd_peer_config_new(void) { return peer; } +/** Frees a peer config (which must not be referenced anywhere) */ void fastd_peer_config_free(fastd_peer_config_t *peer) { while (peer->remotes) { fastd_remote_config_t *remote = peer->remotes; @@ -404,12 +454,14 @@ void fastd_peer_config_free(fastd_peer_config_t *peer) { free(peer); } +/** Deletes the peer config created last */ void fastd_peer_config_delete(void) { fastd_peer_config_t *peer = conf.peers, *next = peer->next; fastd_peer_config_free(peer); conf.peers = next; } +/** Deletes a peer config, and removes the peer assiciated with the peer config */ void fastd_peer_config_purge(fastd_peer_config_t *config) { size_t i; for (i = 0; i < VECTOR_LEN(ctx.peers); i++) { @@ -424,6 +476,7 @@ void fastd_peer_config_purge(fastd_peer_config_t *config) { fastd_peer_config_free(config); } +/** Checks if two fastd_peer_address_t are equal */ bool fastd_peer_address_equal(const fastd_peer_address_t *addr1, const fastd_peer_address_t *addr2) { if (addr1->sa.sa_family != addr2->sa.sa_family) return false; @@ -453,6 +506,7 @@ bool fastd_peer_address_equal(const fastd_peer_address_t *addr1, const fastd_pee return true; } +/** If \e addr is a v4-mapped IPv6 address, it is converted to an IPv4 address */ void fastd_peer_address_simplify(fastd_peer_address_t *addr) { if (addr->sa.sa_family == AF_INET6 && IN6_IS_ADDR_V4MAPPED(&addr->in6.sin6_addr)) { struct sockaddr_in6 mapped = addr->in6; @@ -464,6 +518,7 @@ void fastd_peer_address_simplify(fastd_peer_address_t *addr) { } } +/** If \e addr is an IPv4 address, it is converted to a v4-mapped IPv6 address */ void fastd_peer_address_widen(fastd_peer_address_t *addr) { if (addr->sa.sa_family == AF_INET) { struct sockaddr_in addr4 = addr->in; @@ -478,6 +533,7 @@ void fastd_peer_address_widen(fastd_peer_address_t *addr) { } +/** Resets a peer's address to the unspecified address */ static inline void reset_peer_address(fastd_peer_t *peer) { if (fastd_peer_is_established(peer)) fastd_peer_reset(peer); @@ -486,6 +542,7 @@ static inline void reset_peer_address(fastd_peer_t *peer) { memset(&peer->address, 0, sizeof(fastd_peer_address_t)); } +/** Checks if an address is statically configured for a peer */ bool fastd_peer_owns_address(const fastd_peer_t *peer, const fastd_peer_address_t *addr) { if (fastd_peer_is_floating(peer)) return false; @@ -502,6 +559,7 @@ bool fastd_peer_owns_address(const fastd_peer_t *peer, const fastd_peer_address_ return false; } +/** Checks if an address matches any of the configured or resolved remotes of a peer */ bool fastd_peer_matches_address(const fastd_peer_t *peer, const fastd_peer_address_t *addr) { if (fastd_peer_is_floating(peer)) return true; @@ -519,6 +577,15 @@ bool fastd_peer_matches_address(const fastd_peer_t *peer, const fastd_peer_addre return false; } +/** + Tries to claim an address for a peer + + Each remote address (+ port) can by used by only one peer at a time. + + If it is tried to claim an address that is currently used by another peer, the claim will fail unless + \e force is set. The claim will fail even with \e force set if the other peer has statically configured the address + in question. + */ bool fastd_peer_claim_address(fastd_peer_t *new_peer, fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, bool force) { if (remote_addr->sa.sa_family == AF_UNSPEC) { if (fastd_peer_is_established(new_peer)) @@ -567,6 +634,7 @@ bool fastd_peer_claim_address(fastd_peer_t *new_peer, fastd_socket_t *sock, cons return true; } +/** Checks if two remote configs are equivalent */ static bool remote_configs_equal(const fastd_remote_config_t *remote1, const fastd_remote_config_t *remote2) { if (!remote1 && !remote2) return true; @@ -583,6 +651,7 @@ static bool remote_configs_equal(const fastd_remote_config_t *remote1, const fas return remote_configs_equal(remote1->next, remote2->next); } +/** Checks if two peer configs are equivalent */ bool fastd_peer_config_equal(const fastd_peer_config_t *peer1, const fastd_peer_config_t *peer2) { if (peer1->group != peer2->group) return false; @@ -599,6 +668,7 @@ bool fastd_peer_config_equal(const fastd_peer_config_t *peer1, const fastd_peer_ return true; } +/** Resets and re-initializes a peer */ void fastd_peer_reset(fastd_peer_t *peer) { pr_debug("resetting peer %P", peer); @@ -606,11 +676,13 @@ void fastd_peer_reset(fastd_peer_t *peer) { setup_peer(peer); } +/** Deletes a peer */ void fastd_peer_delete(fastd_peer_t *peer) { reset_peer(peer); delete_peer(peer); } +/** Counts how many peers in the given peer group have established a connection */ static inline size_t count_established_group_peers(const fastd_peer_group_t *group) { size_t i, ret = 0; for (i = 0; i < VECTOR_LEN(ctx.peers); i++) { @@ -623,6 +695,7 @@ static inline size_t count_established_group_peers(const fastd_peer_group_t *gro return ret; } +/** Checks if a peer may currently establish a connection */ bool fastd_peer_may_connect(fastd_peer_t *peer) { if (fastd_peer_is_established(peer)) return true; @@ -640,6 +713,7 @@ bool fastd_peer_may_connect(fastd_peer_t *peer) { return true; } +/** Create a new peer */ fastd_peer_t* fastd_peer_add(fastd_peer_config_t *peer_conf) { fastd_peer_t *peer = calloc(1, sizeof(fastd_peer_t)); @@ -688,10 +762,12 @@ fastd_peer_t* fastd_peer_add(fastd_peer_config_t *peer_conf) { return peer; } +/** Prints a debug message when no handshake could be sent because the current remote didn't resolve successfully */ static inline void no_valid_address_debug(const fastd_peer_t *peer) { pr_debug("not sending a handshake to %P (no valid address resolved)", peer); } +/** Sends a new handshake to the current address of the given remote of a peer */ static void send_handshake(fastd_peer_t *peer, fastd_remote_t *next_remote) { if (!fastd_peer_is_established(peer)) { if (!next_remote->n_addresses) { @@ -723,6 +799,7 @@ static void send_handshake(fastd_peer_t *peer, fastd_remote_t *next_remote) { conf.protocol->handshake_init(peer->sock, &peer->local_address, &peer->address, peer); } +/** Sends a handshake to one peer, if a scheduled handshake is due */ void fastd_peer_handle_handshake_queue(void) { if (!ctx.handshake_queue.next) return; @@ -766,6 +843,7 @@ void fastd_peer_handle_handshake_queue(void) { fastd_resolve_peer(peer, next_remote); } +/** Marks a peer as established */ void fastd_peer_set_established(fastd_peer_t *peer) { if (fastd_peer_is_established(peer)) return; @@ -775,6 +853,7 @@ void fastd_peer_set_established(fastd_peer_t *peer) { pr_info("connection with %P established.", peer); } +/** Checks if an address would be a valid address which could be resolved for a given remote config */ bool fastd_remote_matches_dynamic(const fastd_remote_config_t *remote, const fastd_peer_address_t *addr) { if (!remote->hostname) return false; @@ -795,14 +874,17 @@ bool fastd_remote_matches_dynamic(const fastd_remote_config_t *remote, const fas return true; } +/** Compares two MAC addresses */ static inline int eth_addr_cmp(const fastd_eth_addr_t *addr1, const fastd_eth_addr_t *addr2) { return memcmp(addr1->data, addr2->data, ETH_ALEN); } +/** Compares two fastd_peer_eth_addr_t entries by their MAC addresses */ static int peer_eth_addr_cmp(const fastd_peer_eth_addr_t *addr1, const fastd_peer_eth_addr_t *addr2) { return eth_addr_cmp(&addr1->addr, &addr2->addr); } +/** Adds a MAC address to the sorted list of addresses associated with a peer (or updates the timeout of an existing entry) */ void fastd_peer_eth_addr_add(fastd_peer_t *peer, fastd_eth_addr_t addr) { int min = 0, max = VECTOR_LEN(ctx.eth_addrs); @@ -831,6 +913,7 @@ void fastd_peer_eth_addr_add(fastd_peer_t *peer, fastd_eth_addr_t addr) { pr_debug("learned new MAC address %E on peer %P", &addr, peer); } +/** Finds the peer that is associated with a given MAC address */ fastd_peer_t* fastd_peer_find_by_eth_addr(const fastd_eth_addr_t addr) { const fastd_peer_eth_addr_t key = {.addr = addr}; fastd_peer_eth_addr_t *peer_eth_addr = VECTOR_BSEARCH(&key, ctx.eth_addrs, peer_eth_addr_cmp); @@ -841,6 +924,12 @@ fastd_peer_t* fastd_peer_find_by_eth_addr(const fastd_eth_addr_t addr) { return NULL; } +/** + Performs maintenance tasks for a peer + + \li If no data was received from the peer for some time, it is reset. + \li If no data was sent to the peer for some time, a keepalive is sent. + */ static bool maintain_peer(fastd_peer_t *peer) { if (fastd_peer_is_temporary(peer) || fastd_peer_is_established(peer)) { /* check for peer timeout */ @@ -873,6 +962,7 @@ static bool maintain_peer(fastd_peer_t *peer) { return true; } +/** Removes all time-outed MAC addresses from \e ctx.eth_addrs */ static void eth_addr_cleanup(void) { size_t i, deleted = 0; @@ -890,6 +980,7 @@ static void eth_addr_cleanup(void) { VECTOR_RESIZE(ctx.eth_addrs, VECTOR_LEN(ctx.eth_addrs)-deleted); } +/** Performs periodic maintenance tasks for peers */ void fastd_peer_maintenance(void) { size_t i; for (i = 0; i < VECTOR_LEN(ctx.peers);) { -- cgit v1.2.3