自学教程：C++ sock_init_data函数代码示例

static int hidp_sock_create(struct socket *sock, int protocol){	struct sock *sk;	BT_DBG("sock %p", sock);	if (sock->type != SOCK_RAW)		return -ESOCKTNOSUPPORT;	sk = sk_alloc(PF_BLUETOOTH, GFP_KERNEL, &hidp_proto, 1);	if (!sk)		return -ENOMEM;	sock_init_data(sock, sk);	sock->ops = &hidp_sock_ops;	sock->state = SS_UNCONNECTED;	sock_reset_flag(sk, SOCK_ZAPPED);	sk->sk_protocol = protocol;	sk->sk_state	= BT_OPEN;	return 0;}

struct sk_filter *pfq_alloc_sk_filter(struct sock_fprog *fprog){	struct sock sk;	int rv;	sock_init_data(NULL, &sk);	sk.sk_filter = NULL;	atomic_set(&sk.sk_omem_alloc, 0);#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,9,0))	sock_reset_flag(&sk, SOCK_FILTER_LOCKED);#endif        pr_devel("[PFQ] BPF: new fprog (len %d)/n", fprog->len);#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,4,8) && LINUX_VERSION_CODE < KERNEL_VERSION(4,7,0))	if ((rv = __sk_attach_filter(fprog, &sk, sock_owned_by_user(&sk))))#else	if ((rv = sk_attach_filter(fprog, &sk)))#endif	{		pr_devel("[PFQ] BPF: sk_attach_filter error: (%d)!/n", rv);		return NULL;	}	return sk.sk_filter;}

static int cmtp_sock_create(struct net *net, struct socket *sock, int protocol,			    int kern){	struct sock *sk;	BT_DBG("sock %p", sock);	if (sock->type != SOCK_RAW)		return -ESOCKTNOSUPPORT;	sk = sk_alloc(net, PF_BLUETOOTH, GFP_ATOMIC, &cmtp_proto);	if (!sk)		return -ENOMEM;	sock_init_data(sock, sk);	sock->ops = &cmtp_sock_ops;	sock->state = SS_UNCONNECTED;	sock_reset_flag(sk, SOCK_ZAPPED);	sk->sk_protocol = protocol;	sk->sk_state    = BT_OPEN;	return 0;}

int vcc_create(struct socket *sock, int protocol, int family){	struct sock *sk;	struct atm_vcc *vcc;	sock->sk = NULL;	if (sock->type == SOCK_STREAM)		return -EINVAL;	sk = sk_alloc(family, GFP_KERNEL, &vcc_proto, 1);	if (!sk)		return -ENOMEM;	sock_init_data(sock, sk);	sk->sk_state_change = vcc_def_wakeup;	sk->sk_write_space = vcc_write_space;	vcc = atm_sk(sk);	vcc->dev = NULL;	memset(&vcc->local,0,sizeof(struct sockaddr_atmsvc));	memset(&vcc->remote,0,sizeof(struct sockaddr_atmsvc));	vcc->qos.txtp.max_sdu = 1 << 16; /* for meta VCs */	atomic_set(&sk->sk_wmem_alloc, 0);	atomic_set(&sk->sk_rmem_alloc, 0);	vcc->push = NULL;	vcc->pop = NULL;	vcc->push_oam = NULL;	vcc->vpi = vcc->vci = 0; /* no VCI/VPI yet */	vcc->atm_options = vcc->aal_options = 0;	sk->sk_destruct = vcc_sock_destruct;	return 0;}

/** * tipc_create - create a TIPC socket * @sock: pre-allocated socket structure * @protocol: protocol indicator (must be 0) * * This routine creates and attaches a 'struct sock' to the 'struct socket', * then create and attaches a TIPC port to the 'struct sock' part. * * Returns 0 on success, errno otherwise */static int tipc_create(struct socket *sock, int protocol){	struct tipc_sock *tsock;	struct tipc_port *port;	struct sock *sk;	u32 ref;	if (unlikely(protocol != 0))		return -EPROTONOSUPPORT;	ref = tipc_createport_raw(NULL, &dispatch, &wakeupdispatch, TIPC_LOW_IMPORTANCE);	if (unlikely(!ref))		return -ENOMEM;	sock->state = SS_UNCONNECTED;	switch (sock->type) {	case SOCK_STREAM:		sock->ops = &stream_ops;		break;	case SOCK_SEQPACKET:		sock->ops = &packet_ops;		break;	case SOCK_DGRAM:		tipc_set_portunreliable(ref, 1);		/* fall through */	case SOCK_RDM:		tipc_set_portunreturnable(ref, 1);		sock->ops = &msg_ops;		sock->state = SS_READY;		break;	default:		tipc_deleteport(ref);		return -EPROTOTYPE;	}	sk = sk_alloc(AF_TIPC, GFP_KERNEL, &tipc_proto, 1);	if (!sk) {		tipc_deleteport(ref);		return -ENOMEM;	}	sock_init_data(sock, sk);	init_waitqueue_head(sk->sk_sleep);	sk->sk_rcvtimeo = 8 * HZ;   /* default connect timeout = 8s */	tsock = tipc_sk(sk);	port = tipc_get_port(ref);	tsock->p = port;	port->usr_handle = tsock;	init_MUTEX(&tsock->sem);	dbg("sock_create: %x/n",tsock);	atomic_inc(&tipc_user_count);	return 0;}

static int netlink_create(struct socket *sock, int protocol){	struct sock *sk;	sock->state = SS_UNCONNECTED;	if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)		return -ESOCKTNOSUPPORT;	if (protocol<0 || protocol >= MAX_LINKS)		return -EPROTONOSUPPORT;	sock->ops = &netlink_ops;	sk = sk_alloc(PF_NETLINK, GFP_KERNEL, 1);	if (!sk)		return -ENOMEM;	sock_init_data(sock,sk);	sk->protinfo.af_netlink = kmalloc(sizeof(struct netlink_opt), GFP_KERNEL);	if (sk->protinfo.af_netlink == NULL) {		sk_free(sk);		return -ENOMEM;	}	memset(sk->protinfo.af_netlink, 0, sizeof(struct netlink_opt));	spin_lock_init(&sk->protinfo.af_netlink->cb_lock);	init_waitqueue_head(&sk->protinfo.af_netlink->wait);	sk->destruct = netlink_sock_destruct;	atomic_inc(&netlink_sock_nr);	sk->protocol=protocol;	return 0;}

static int rawsock_create(struct net *net, struct socket *sock,				const struct nfc_protocol *nfc_proto){	struct sock *sk;	nfc_dbg("sock=%p", sock);	if (sock->type != SOCK_SEQPACKET)		return -ESOCKTNOSUPPORT;	sock->ops = &rawsock_ops;	sk = sk_alloc(net, PF_NFC, GFP_KERNEL, nfc_proto->proto);	if (!sk)		return -ENOMEM;	sock_init_data(sock, sk);	sk->sk_protocol = nfc_proto->id;	sk->sk_destruct = rawsock_destruct;	sock->state = SS_UNCONNECTED;	INIT_WORK(&nfc_rawsock(sk)->tx_work, rawsock_tx_work);	nfc_rawsock(sk)->tx_work_scheduled = false;	return 0;}

static int mpls_create(struct net *net, struct socket *sock, int protocol,                       int kern){	struct sock *sk;        if (net != &init_net)		return -EAFNOSUPPORT;	sock->state = SS_UNCONNECTED;	sock->ops = &mpls_sk_ops;	sk = sk_alloc(net, PF_INET, GFP_KERNEL, &mpls_proto);        if (!sk)                return -1;	sock_init_data(sock, sk);	sk->sk_destruct    = mpls_sock_destruct;	sk->sk_family      = PF_MPLS;	sk->sk_protocol    = 0;	sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;	sock_reset_flag(sk, SOCK_ZAPPED);	return 0;}

static int hci_sock_create(struct socket *sock, int protocol){	struct sock *sk;	BT_DBG("sock %p", sock);	if (sock->type != SOCK_RAW)		return -ESOCKTNOSUPPORT;	sock->ops = &hci_sock_ops;	if (!(sk = sk_alloc(PF_BLUETOOTH, GFP_KERNEL, 1)))		return -ENOMEM;	sock->state = SS_UNCONNECTED;	sock_init_data(sock, sk);	memset(&sk->protinfo, 0, sizeof(struct hci_pinfo));	sk->destruct = NULL;	sk->protocol = protocol;	sk->state    = BT_OPEN;	bluez_sock_link(&hci_sk_list, sk);	MOD_INC_USE_COUNT;	return 0;}