C++ put_cmsg函数代码示例

/**
 * anc_data_recv - optionally capture ancillary data for received message
 * @m: descriptor for message info
 * @msg: received message header
 * @tport: TIPC port associated with message
 *
 * Note: Ancillary data is not captured if not requested by receiver.
 *
 * Returns 0 if successful, otherwise errno
 */
static int anc_data_recv(struct msghdr *m, struct tipc_msg *msg,
				struct tipc_port *tport)
{
	u32 anc_data[3];
	u32 err;
	u32 dest_type;
	int has_name;
	int res;

	if (likely(m->msg_controllen == 0))
		return 0;

	/* Optionally capture errored message object(s) */
	err = msg ? msg_errcode(msg) : 0;
	if (unlikely(err)) {
		anc_data[0] = err;
		anc_data[1] = msg_data_sz(msg);
		res = put_cmsg(m, SOL_TIPC, TIPC_ERRINFO, 8, anc_data);
		if (res)
			return res;
		if (anc_data[1]) {
			res = put_cmsg(m, SOL_TIPC, TIPC_RETDATA, anc_data[1],
				       msg_data(msg));
			if (res)
				return res;
		}
	}

	/* Optionally capture message destination object */
	dest_type = msg ? msg_type(msg) : TIPC_DIRECT_MSG;
	switch (dest_type) {
	case TIPC_NAMED_MSG:
		has_name = 1;
		anc_data[0] = msg_nametype(msg);
		anc_data[1] = msg_namelower(msg);
		anc_data[2] = msg_namelower(msg);
		break;
	case TIPC_MCAST_MSG:
		has_name = 1;
		anc_data[0] = msg_nametype(msg);
		anc_data[1] = msg_namelower(msg);
		anc_data[2] = msg_nameupper(msg);
		break;
	case TIPC_CONN_MSG:
		has_name = (tport->conn_type != 0);
		anc_data[0] = tport->conn_type;
		anc_data[1] = tport->conn_instance;
		anc_data[2] = tport->conn_instance;
		break;
	default:
		has_name = 0;
	}
	if (has_name) {
		res = put_cmsg(m, SOL_TIPC, TIPC_DESTNAME, 12, anc_data);
		if (res)
			return res;
	}

	return 0;
}

static inline void hci_sock_cmsg(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)
{
	__u32 mask = hci_pi(sk)->cmsg_mask;

	if (mask & HCI_CMSG_DIR)
        	put_cmsg(msg, SOL_HCI, HCI_CMSG_DIR, sizeof(int), &bluez_cb(skb)->incomming);

	if (mask & HCI_CMSG_TSTAMP)
        	put_cmsg(msg, SOL_HCI, HCI_CMSG_TSTAMP, sizeof(skb->stamp), &skb->stamp);
}

static void ip_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
{
	struct in_pktinfo info = *PKTINFO_SKB_CB(skb);

	info.ipi_addr.s_addr = ip_hdr(skb)->daddr;

	put_cmsg(msg, SOL_IP, IP_PKTINFO, sizeof(info), &info);
}

static void ip_cmsg_recv_opts(struct msghdr *msg, struct sk_buff *skb)
{
	if (IPCB(skb)->opt.optlen == 0)
		return;

	put_cmsg(msg, SOL_IP, IP_RECVOPTS, IPCB(skb)->opt.optlen,
		 ip_hdr(skb) + 1);
}

static void ip_cmsg_recv_fragsize(struct msghdr *msg, struct sk_buff *skb)
{
	int val;

	if (IPCB(skb)->frag_max_size == 0)
		return;

	val = IPCB(skb)->frag_max_size;
	put_cmsg(msg, SOL_IP, IP_RECVFRAGSIZE, sizeof(val), &val);
}

static inline void
mISDN_sock_cmsg(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)
{
	struct timeval	tv;

	if (_pms(sk)->cmask & MISDN_TIME_STAMP) {
		skb_get_timestamp(skb, &tv);
		put_cmsg(msg, SOL_MISDN, MISDN_TIME_STAMP, sizeof(tv), &tv);
	}
}

static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
				  int offset)
{
	__wsum csum = skb->csum;

	if (skb->ip_summed != CHECKSUM_COMPLETE)
		return;

	if (offset != 0)
		csum = csum_sub(csum, csum_partial(skb->data, offset, 0));

	put_cmsg(msg, SOL_IP, IP_CHECKSUM, sizeof(__wsum), &csum);
}

int datagram_recv_ctl(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct inet6_skb_parm *opt = IP6CB(skb);
	unsigned char *nh = skb_network_header(skb);

	if (np->rxopt.bits.rxinfo) {
		struct in6_pktinfo src_info;

		src_info.ipi6_ifindex = opt->iif;
		ipv6_addr_copy(&src_info.ipi6_addr, &ipv6_hdr(skb)->daddr);
		put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info);
	}

	if (np->rxopt.bits.rxhlim) {
		int hlim = ipv6_hdr(skb)->hop_limit;
		put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
	}

	if (np->rxopt.bits.rxtclass) {
		int tclass = (ntohl(*(__be32 *)ipv6_hdr(skb)) >> 20) & 0xff;
		put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
	}

static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
				  int tlen, int offset)
{
	__wsum csum = skb->csum;

	if (skb->ip_summed != CHECKSUM_COMPLETE)
		return;

	if (offset != 0) {
		int tend_off = skb_transport_offset(skb) + tlen;
		csum = csum_sub(csum, skb_checksum(skb, tend_off, offset, 0));
	}

	put_cmsg(msg, SOL_IP, IP_CHECKSUM, sizeof(__wsum), &csum);
}

static void ip_cmsg_recv_retopts(struct msghdr *msg, struct sk_buff *skb)
{
	unsigned char optbuf[sizeof(struct ip_options) + 40];
	struct ip_options *opt = (struct ip_options *)optbuf;

	if (IPCB(skb)->opt.optlen == 0)
		return;

	if (ip_options_echo(opt, skb)) {
		msg->msg_flags |= MSG_CTRUNC;
		return;
	}
	ip_options_undo(opt);

	put_cmsg(msg, SOL_IP, IP_RETOPTS, opt->optlen, opt->__data);
}

static void ip_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
{
	struct in_pktinfo info;
	struct rtable *rt = skb_rtable(skb);

	info.ipi_addr.s_addr = ip_hdr(skb)->daddr;
	if (rt) {
		info.ipi_ifindex = rt->rt_iif;
		info.ipi_spec_dst.s_addr = rt->rt_spec_dst;
	} else {
		info.ipi_ifindex = 0;
		info.ipi_spec_dst.s_addr = 0;
	}

	put_cmsg(msg, SOL_IP, IP_PKTINFO, sizeof(info), &info);
}

/*
 *	Handle IPV6_RECVPATHMTU
 */
int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len,
		     int *addr_len)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct sk_buff *skb;
	struct sockaddr_in6 *sin;
	struct ip6_mtuinfo mtu_info;
	int err;
	int copied;

	err = -EAGAIN;
	skb = xchg(&np->rxpmtu, NULL);
	if (skb == NULL)
		goto out;

	copied = skb->len;
	if (copied > len) {
		msg->msg_flags |= MSG_TRUNC;
		copied = len;
	}
	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
	if (err)
		goto out_free_skb;

	sock_recv_timestamp(msg, sk, skb);

	memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));

	sin = (struct sockaddr_in6 *)msg->msg_name;
	if (sin) {
		sin->sin6_family = AF_INET6;
		sin->sin6_flowinfo = 0;
		sin->sin6_port = 0;
		sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;
		ipv6_addr_copy(&sin->sin6_addr, &mtu_info.ip6m_addr.sin6_addr);
		*addr_len = sizeof(*sin);
	}

	put_cmsg(msg, SOL_IPV6, IPV6_PATHMTU, sizeof(mtu_info), &mtu_info);

	err = copied;

out_free_skb:
	kfree_skb(skb);
out:
	return err;
}

static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
{
	char *secdata;
	u32 seclen, secid;
	int err;

	err = security_socket_getpeersec_dgram(NULL, skb, &secid);
	if (err)
		return;

	err = security_secid_to_secctx(secid, &secdata, &seclen);
	if (err)
		return;

	put_cmsg(msg, SOL_IP, SCM_SECURITY, seclen, secdata);
	security_release_secctx(secdata, seclen);
}

/* RFC6458, Section 5.3.6. SCTP Next Receive Information Structure
 * (SCTP_NXTINFO)
 */
static void __sctp_ulpevent_read_nxtinfo(const struct sctp_ulpevent *event,
					 struct msghdr *msghdr,
					 const struct sk_buff *skb)
{
	struct sctp_nxtinfo nxtinfo;

	memset(&nxtinfo, 0, sizeof(nxtinfo));
	nxtinfo.nxt_sid = event->stream;
	nxtinfo.nxt_ppid = event->ppid;
	nxtinfo.nxt_flags = event->flags;
	if (sctp_ulpevent_is_notification(event))
		nxtinfo.nxt_flags |= SCTP_NOTIFICATION;
	nxtinfo.nxt_length = skb->len;
	nxtinfo.nxt_assoc_id = sctp_assoc2id(event->asoc);

	put_cmsg(msghdr, IPPROTO_SCTP, SCTP_NXTINFO,
		 sizeof(nxtinfo), &nxtinfo);
}

static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb)
{
	__be16 _ports[2], *ports;
	struct sockaddr_in sin;

	/* All current transport protocols have the port numbers in the
	 * first four bytes of the transport header and this function is
	 * written with this assumption in mind.
	 */
	ports = skb_header_pointer(skb, skb_transport_offset(skb),
				   sizeof(_ports), &_ports);
	if (!ports)
		return;

	sin.sin_family = AF_INET;
	sin.sin_addr.s_addr = ip_hdr(skb)->daddr;
	sin.sin_port = ports[1];
	memset(sin.sin_zero, 0, sizeof(sin.sin_zero));

	put_cmsg(msg, SOL_IP, IP_ORIGDSTADDR, sizeof(sin), &sin);
}