/**
* accept a connection
*
* event handler for listening connections
*
* @param srv a listening socket
*
*/
network_socket *network_socket_accept(network_socket *srv) {
network_socket *client;
g_return_val_if_fail(srv, NULL);
g_return_val_if_fail(srv->socket_type == SOCK_STREAM, NULL); /* accept() only works on stream sockets */
client = network_socket_new();
if (-1 == (client->fd = accept4(srv->fd, &client->src->addr.common, &(client->src->len), SOCK_NONBLOCK))) {
network_socket_free(client);
return NULL;
}
if (network_address_refresh_name(client->src)) {
network_socket_free(client);
return NULL;
}
/* the listening side may be INADDR_ANY, let's get which address the client really connected to */
if (-1 == getsockname(client->fd, &client->dst->addr.common, &(client->dst->len))) {
network_address_reset(client->dst);
} else if (network_address_refresh_name(client->dst)) {
network_address_reset(client->dst);
}
return client;
}
/**
* free a conn pool entry
*
* @param e the pool entry to free
* @param free_sock if true, the attached server-socket will be freed too
*/
void network_connection_pool_entry_free(network_connection_pool_entry *e, gboolean free_sock) {
if (!e) return;
if (e->sock && free_sock) {
network_socket *sock = e->sock;
event_del(&(sock->event));
network_socket_free(sock);
}
g_free(e);
}
/**
* add a connection to the connection pool
*
*/
network_connection_pool_entry *network_connection_pool_add(network_connection_pool *pool, network_socket *sock) {
if (pool) {
network_connection_pool_entry *entry = network_connection_pool_entry_new();
if (entry) {
entry->sock = sock;
entry->pool = pool;
g_queue_push_tail(pool, entry);
return entry;
}
}
network_socket_free(sock);
return NULL;
}
network_socket *self_connect(network_mysqld_con *con, network_backend_t *backend, GHashTable *pwd_table) {
/*make sure that the max conn for the backend is no more than the config number
*when max_conn_for_a_backend is no more than 0, there is no limitation for max connection for a backend;
* */
if (con->srv->max_conn_for_a_backend > 0 && backend->connected_clients >= con->srv->max_conn_for_a_backend) {
g_critical("%s.%d: self_connect:%08x's connected_clients is %d, which are too many!",__FILE__, __LINE__, backend, backend->connected_clients);
return NULL;
}
//1. connect DB
network_socket *sock = network_socket_new();
network_address_copy(sock->dst, backend->addr);
if (-1 == (sock->fd = socket(sock->dst->addr.common.sa_family, sock->socket_type, 0))) {
g_critical("%s.%d: socket(%s) failed: %s (%d)", __FILE__, __LINE__, sock->dst->name->str, g_strerror(errno), errno);
network_socket_free(sock);
return NULL;
}
if (-1 == (connect(sock->fd, &sock->dst->addr.common, sock->dst->len))) {
g_message("%s.%d: connecting to backend (%s) failed, marking it as down for ...", __FILE__, __LINE__, sock->dst->name->str);
network_socket_free(sock);
if (backend->state != BACKEND_STATE_OFFLINE) backend->state = BACKEND_STATE_DOWN;
return NULL;
}
//2. read handshake，重点是获取20个字节的随机串
off_t to_read = NET_HEADER_SIZE;
guint offset = 0;
guchar header[NET_HEADER_SIZE];
while (to_read > 0) {
gssize len = recv(sock->fd, header + offset, to_read, 0);
if (len == -1 || len == 0) {
network_socket_free(sock);
return NULL;
}
offset += len;
to_read -= len;
}
to_read = header[0] + (header[1] << 8) + (header[2] << 16);
offset = 0;
GString *data = g_string_sized_new(to_read);
while (to_read > 0) {
gssize len = recv(sock->fd, data->str + offset, to_read, 0);
if (len == -1 || len == 0) {
network_socket_free(sock);
g_string_free(data, TRUE);
return NULL;
}
offset += len;
to_read -= len;
}
data->len = offset;
network_packet packet;
packet.data = data;
packet.offset = 0;
network_mysqld_auth_challenge *challenge = network_mysqld_auth_challenge_new();
network_mysqld_proto_get_auth_challenge(&packet, challenge);
//3. 生成response
GString *response = g_string_sized_new(20);
GString *hashed_password = g_hash_table_lookup(pwd_table, con->client->response->username->str);
if (hashed_password) {
network_mysqld_proto_password_scramble(response, S(challenge->challenge), S(hashed_password));
} else {
network_socket_free(sock);
g_string_free(data, TRUE);
network_mysqld_auth_challenge_free(challenge);
g_string_free(response, TRUE);
return NULL;
}
//4. send auth
off_t to_write = 58 + con->client->response->username->len;
offset = 0;
g_string_truncate(data, 0);
char tmp[] = {to_write - 4, 0, 0, 1, 0x85, 0xa6, 3, 0, 0, 0, 0, 1, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
g_string_append_len(data, tmp, 36);
g_string_append_len(data, con->client->response->username->str, con->client->response->username->len);
g_string_append_len(data, "\0\x14", 2);
g_string_append_len(data, response->str, 20);
g_string_free(response, TRUE);
while (to_write > 0) {
gssize len = send(sock->fd, data->str + offset, to_write, 0);
if (len == -1) {
network_socket_free(sock);
g_string_free(data, TRUE);
network_mysqld_auth_challenge_free(challenge);
return NULL;
}
offset += len;
to_write -= len;
}
//5. read auth result
to_read = NET_HEADER_SIZE;
offset = 0;
while (to_read > 0) {
gssize len = recv(sock->fd, header + offset, to_read, 0);
if (len == -1 || len == 0) {
network_socket_free(sock);
g_string_free(data, TRUE);
network_mysqld_auth_challenge_free(challenge);
return NULL;
}
offset += len;
to_read -= len;
}
to_read = header[0] + (header[1] << 8) + (header[2] << 16);
offset = 0;
g_string_truncate(data, 0);
g_string_set_size(data, to_read);
while (to_read > 0) {
gssize len = recv(sock->fd, data->str + offset, to_read, 0);
if (len == -1 || len == 0) {
network_socket_free(sock);
g_string_free(data, TRUE);
network_mysqld_auth_challenge_free(challenge);
return NULL;
}
offset += len;
to_read -= len;
}
data->len = offset;
if (data->str[0] != MYSQLD_PACKET_OK) {
network_socket_free(sock);
g_string_free(data, TRUE);
network_mysqld_auth_challenge_free(challenge);
return NULL;
}
g_string_free(data, TRUE);
//6. set non-block
network_socket_set_non_blocking(sock);
network_socket_connect_setopts(sock); //此句是否需要？是否应该放在第1步末尾？
sock->challenge = challenge;
sock->response = network_mysqld_auth_response_copy(con->client->response);
g_atomic_int_inc(&backend->connected_clients);
return sock;
}