1 files changed, 720 insertions, 0 deletions

diff --git a/package/libnl-tiny/src/nl.c b/package/libnl-tiny/src/nl.c
new file mode 100644
index 0000000..99e9aeb
--- /dev/null
+++ b/package/libnl-tiny/src/nl.c
@@ -0,0 +1,720 @@
+/*
+ * lib/nl.c		Core Netlink Interface
+ *
+ *	This library is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU Lesser General Public
+ *	License as published by the Free Software Foundation version 2.1
+ *	of the License.
+ *
+ * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
+ */
+
+/**
+ * @defgroup core Core
+ *
+ * @details
+ * @par 1) Connecting the socket
+ * @code
+ * // Bind and connect the socket to a protocol, NETLINK_ROUTE in this example.
+ * nl_connect(sk, NETLINK_ROUTE);
+ * @endcode
+ *
+ * @par 2) Sending data
+ * @code
+ * // The most rudimentary method is to use nl_sendto() simply pushing
+ * // a piece of data to the other netlink peer. This method is not
+ * // recommended.
+ * const char buf[] = { 0x01, 0x02, 0x03, 0x04 };
+ * nl_sendto(sk, buf, sizeof(buf));
+ *
+ * // A more comfortable interface is nl_send() taking a pointer to
+ * // a netlink message.
+ * struct nl_msg *msg = my_msg_builder();
+ * nl_send(sk, nlmsg_hdr(msg));
+ *
+ * // nl_sendmsg() provides additional control over the sendmsg() message
+ * // header in order to allow more specific addressing of multiple peers etc.
+ * struct msghdr hdr = { ... };
+ * nl_sendmsg(sk, nlmsg_hdr(msg), &hdr);
+ *
+ * // You're probably too lazy to fill out the netlink pid, sequence number
+ * // and message flags all the time. nl_send_auto_complete() automatically
+ * // extends your message header as needed with an appropriate sequence
+ * // number, the netlink pid stored in the netlink socket and the message
+ * // flags NLM_F_REQUEST and NLM_F_ACK (if not disabled in the socket)
+ * nl_send_auto_complete(sk, nlmsg_hdr(msg));
+ *
+ * // Simple protocols don't require the complex message construction interface
+ * // and may favour nl_send_simple() to easly send a bunch of payload
+ * // encapsulated in a netlink message header.
+ * nl_send_simple(sk, MY_MSG_TYPE, 0, buf, sizeof(buf));
+ * @endcode
+ *
+ * @par 3) Receiving data
+ * @code
+ * // nl_recv() receives a single message allocating a buffer for the message
+ * // content and gives back the pointer to you.
+ * struct sockaddr_nl peer;
+ * unsigned char *msg;
+ * nl_recv(sk, &peer, &msg);
+ *
+ * // nl_recvmsgs() receives a bunch of messages until the callback system
+ * // orders it to state, usually after receving a compolete multi part
+ * // message series.
+ * nl_recvmsgs(sk, my_callback_configuration);
+ *
+ * // nl_recvmsgs_default() acts just like nl_recvmsg() but uses the callback
+ * // configuration stored in the socket.
+ * nl_recvmsgs_default(sk);
+ *
+ * // In case you want to wait for the ACK to be recieved that you requested
+ * // with your latest message, you can call nl_wait_for_ack()
+ * nl_wait_for_ack(sk);
+ * @endcode
+ *
+ * @par 4) Closing
+ * @code
+ * // Close the socket first to release kernel memory
+ * nl_close(sk);
+ * @endcode
+ * 
+ * @{
+ */
+
+#include <netlink-local.h>
+#include <netlink/netlink.h>
+#include <netlink/utils.h>
+#include <netlink/handlers.h>
+#include <netlink/msg.h>
+#include <netlink/attr.h>
+
+/**
+ * @name Connection Management
+ * @{
+ */
+
+/**
+ * Create and connect netlink socket.
+ * @arg sk		Netlink socket.
+ * @arg protocol	Netlink protocol to use.
+ *
+ * Creates a netlink socket using the specified protocol, binds the socket
+ * and issues a connection attempt.
+ *
+ * @return 0 on success or a negative error code.
+ */
+int nl_connect(struct nl_sock *sk, int protocol)
+{
+	int err;
+	socklen_t addrlen;
+
+	sk->s_fd = socket(AF_NETLINK, SOCK_RAW, protocol);
+	if (sk->s_fd < 0) {
+		err = -nl_syserr2nlerr(errno);
+		goto errout;
+	}
+
+	if (!(sk->s_flags & NL_SOCK_BUFSIZE_SET)) {
+		err = nl_socket_set_buffer_size(sk, 0, 0);
+		if (err < 0)
+			goto errout;
+	}
+
+	err = bind(sk->s_fd, (struct sockaddr*) &sk->s_local,
+		   sizeof(sk->s_local));
+	if (err < 0) {
+		err = -nl_syserr2nlerr(errno);
+		goto errout;
+	}
+
+	addrlen = sizeof(sk->s_local);
+	err = getsockname(sk->s_fd, (struct sockaddr *) &sk->s_local,
+			  &addrlen);
+	if (err < 0) {
+		err = -nl_syserr2nlerr(errno);
+		goto errout;
+	}
+
+	if (addrlen != sizeof(sk->s_local)) {
+		err = -NLE_NOADDR;
+		goto errout;
+	}
+
+	if (sk->s_local.nl_family != AF_NETLINK) {
+		err = -NLE_AF_NOSUPPORT;
+		goto errout;
+	}
+
+	sk->s_proto = protocol;
+
+	return 0;
+errout:
+	close(sk->s_fd);
+	sk->s_fd = -1;
+
+	return err;
+}
+
+/**
+ * Close/Disconnect netlink socket.
+ * @arg sk		Netlink socket.
+ */
+void nl_close(struct nl_sock *sk)
+{
+	if (sk->s_fd >= 0) {
+		close(sk->s_fd);
+		sk->s_fd = -1;
+	}
+
+	sk->s_proto = 0;
+}
+
+/** @} */
+
+/**
+ * @name Send
+ * @{
+ */
+
+/**
+ * Send raw data over netlink socket.
+ * @arg sk		Netlink socket.
+ * @arg buf		Data buffer.
+ * @arg size		Size of data buffer.
+ * @return Number of characters written on success or a negative error code.
+ */
+int nl_sendto(struct nl_sock *sk, void *buf, size_t size)
+{
+	int ret;
+
+	ret = sendto(sk->s_fd, buf, size, 0, (struct sockaddr *)
+		     &sk->s_peer, sizeof(sk->s_peer));
+	if (ret < 0)
+		return -nl_syserr2nlerr(errno);
+
+	return ret;
+}
+
+/**
+ * Send netlink message with control over sendmsg() message header.
+ * @arg sk		Netlink socket.
+ * @arg msg		Netlink message to be sent.
+ * @arg hdr		Sendmsg() message header.
+ * @return Number of characters sent on sucess or a negative error code.
+ */
+int nl_sendmsg(struct nl_sock *sk, struct nl_msg *msg, struct msghdr *hdr)
+{
+	struct nl_cb *cb;
+	int ret;
+
+	struct iovec iov = {
+		.iov_base = (void *) nlmsg_hdr(msg),
+		.iov_len = nlmsg_hdr(msg)->nlmsg_len,
+	};
+
+	hdr->msg_iov = &iov;
+	hdr->msg_iovlen = 1;
+
+	nlmsg_set_src(msg, &sk->s_local);
+
+	cb = sk->s_cb;
+	if (cb->cb_set[NL_CB_MSG_OUT])
+		if (nl_cb_call(cb, NL_CB_MSG_OUT, msg) != NL_OK)
+			return 0;
+
+	ret = sendmsg(sk->s_fd, hdr, 0);
+	if (ret < 0)
+		return -nl_syserr2nlerr(errno);
+
+	return ret;
+}
+
+
+/**
+ * Send netlink message.
+ * @arg sk		Netlink socket.
+ * @arg msg		Netlink message to be sent.
+ * @see nl_sendmsg()
+ * @return Number of characters sent on success or a negative error code.
+ */
+int nl_send(struct nl_sock *sk, struct nl_msg *msg)
+{
+	struct sockaddr_nl *dst;
+	struct ucred *creds;
+	
+	struct msghdr hdr = {
+		.msg_name = (void *) &sk->s_peer,
+		.msg_namelen = sizeof(struct sockaddr_nl),
+	};
+
+	/* Overwrite destination if specified in the message itself, defaults
+	 * to the peer address of the socket.
+	 */
+	dst = nlmsg_get_dst(msg);
+	if (dst->nl_family == AF_NETLINK)
+		hdr.msg_name = dst;
+
+	/* Add credentials if present. */
+	creds = nlmsg_get_creds(msg);
+	if (creds != NULL) {
+		char buf[CMSG_SPACE(sizeof(struct ucred))];
+		struct cmsghdr *cmsg;
+
+		hdr.msg_control = buf;
+		hdr.msg_controllen = sizeof(buf);
+
+		cmsg = CMSG_FIRSTHDR(&hdr);
+		cmsg->cmsg_level = SOL_SOCKET;
+		cmsg->cmsg_type = SCM_CREDENTIALS;
+		cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
+		memcpy(CMSG_DATA(cmsg), creds, sizeof(struct ucred));
+	}
+
+	return nl_sendmsg(sk, msg, &hdr);
+}
+
+/**
+ * Send netlink message and check & extend header values as needed.
+ * @arg sk		Netlink socket.
+ * @arg msg		Netlink message to be sent.
+ *
+ * Checks the netlink message \c nlh for completness and extends it
+ * as required before sending it out. Checked fields include pid,
+ * sequence nr, and flags.
+ *
+ * @see nl_send()
+ * @return Number of characters sent or a negative error code.
+ */
+int nl_send_auto_complete(struct nl_sock *sk, struct nl_msg *msg)
+{
+	struct nlmsghdr *nlh;
+	struct nl_cb *cb = sk->s_cb;
+
+	nlh = nlmsg_hdr(msg);
+	if (nlh->nlmsg_pid == 0)
+		nlh->nlmsg_pid = sk->s_local.nl_pid;
+
+	if (nlh->nlmsg_seq == 0)
+		nlh->nlmsg_seq = sk->s_seq_next++;
+
+	if (msg->nm_protocol == -1)
+		msg->nm_protocol = sk->s_proto;
+	
+	nlh->nlmsg_flags |= NLM_F_REQUEST;
+
+	if (!(sk->s_flags & NL_NO_AUTO_ACK))
+		nlh->nlmsg_flags |= NLM_F_ACK;
+
+	if (cb->cb_send_ow)
+		return cb->cb_send_ow(sk, msg);
+	else
+		return nl_send(sk, msg);
+}
+
+/**
+ * Send simple netlink message using nl_send_auto_complete()
+ * @arg sk		Netlink socket.
+ * @arg type		Netlink message type.
+ * @arg flags		Netlink message flags.
+ * @arg buf		Data buffer.
+ * @arg size		Size of data buffer.
+ *
+ * Builds a netlink message with the specified type and flags and
+ * appends the specified data as payload to the message.
+ *
+ * @see nl_send_auto_complete()
+ * @return Number of characters sent on success or a negative error code.
+ */
+int nl_send_simple(struct nl_sock *sk, int type, int flags, void *buf,
+		   size_t size)
+{
+	int err;
+	struct nl_msg *msg;
+
+	msg = nlmsg_alloc_simple(type, flags);
+	if (!msg)
+		return -NLE_NOMEM;
+
+	if (buf && size) {
+		err = nlmsg_append(msg, buf, size, NLMSG_ALIGNTO);
+		if (err < 0)
+			goto errout;
+	}
+	
+
+	err = nl_send_auto_complete(sk, msg);
+errout:
+	nlmsg_free(msg);
+
+	return err;
+}
+
+/** @} */
+
+/**
+ * @name Receive
+ * @{
+ */
+
+/**
+ * Receive data from netlink socket
+ * @arg sk		Netlink socket.
+ * @arg nla		Destination pointer for peer's netlink address.
+ * @arg buf		Destination pointer for message content.
+ * @arg creds		Destination pointer for credentials.
+ *
+ * Receives a netlink message, allocates a buffer in \c *buf and
+ * stores the message content. The peer's netlink address is stored
+ * in \c *nla. The caller is responsible for freeing the buffer allocated
+ * in \c *buf if a positive value is returned.  Interruped system calls
+ * are handled by repeating the read. The input buffer size is determined
+ * by peeking before the actual read is done.
+ *
+ * A non-blocking sockets causes the function to return immediately with
+ * a return value of 0 if no data is available.
+ *
+ * @return Number of octets read, 0 on EOF or a negative error code.
+ */
+int nl_recv(struct nl_sock *sk, struct sockaddr_nl *nla,
+	    unsigned char **buf, struct ucred **creds)
+{
+	int n;
+	int flags = 0;
+	static int page_size = 0;
+	struct iovec iov;
+	struct msghdr msg = {
+		.msg_name = (void *) nla,
+		.msg_namelen = sizeof(struct sockaddr_nl),
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+		.msg_control = NULL,
+		.msg_controllen = 0,
+		.msg_flags = 0,
+	};
+	struct cmsghdr *cmsg;
+
+	if (sk->s_flags & NL_MSG_PEEK)
+		flags |= MSG_PEEK;
+
+	if (page_size == 0)
+		page_size = getpagesize();
+
+	iov.iov_len = page_size;
+	iov.iov_base = *buf = malloc(iov.iov_len);
+
+	if (sk->s_flags & NL_SOCK_PASSCRED) {
+		msg.msg_controllen = CMSG_SPACE(sizeof(struct ucred));
+		msg.msg_control = calloc(1, msg.msg_controllen);
+	}
+retry:
+
+	n = recvmsg(sk->s_fd, &msg, flags);
+	if (!n)
+		goto abort;
+	else if (n < 0) {
+		if (errno == EINTR) {
+			NL_DBG(3, "recvmsg() returned EINTR, retrying\n");
+			goto retry;
+		} else if (errno == EAGAIN) {
+			NL_DBG(3, "recvmsg() returned EAGAIN, aborting\n");
+			goto abort;
+		} else {
+			free(msg.msg_control);
+			free(*buf);
+			return -nl_syserr2nlerr(errno);
+		}
+	}
+
+	if (iov.iov_len < n ||
+	    msg.msg_flags & MSG_TRUNC) {
+		/* Provided buffer is not long enough, enlarge it
+		 * and try again. */
+		iov.iov_len *= 2;
+		iov.iov_base = *buf = realloc(*buf, iov.iov_len);
+		goto retry;
+	} else if (msg.msg_flags & MSG_CTRUNC) {
+		msg.msg_controllen *= 2;
+		msg.msg_control = realloc(msg.msg_control, msg.msg_controllen);
+		goto retry;
+	} else if (flags != 0) {
+		/* Buffer is big enough, do the actual reading */
+		flags = 0;
+		goto retry;
+	}
+
+	if (msg.msg_namelen != sizeof(struct sockaddr_nl)) {
+		free(msg.msg_control);
+		free(*buf);
+		return -NLE_NOADDR;
+	}
+
+	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+		if (cmsg->cmsg_level == SOL_SOCKET &&
+		    cmsg->cmsg_type == SCM_CREDENTIALS) {
+			*creds = calloc(1, sizeof(struct ucred));
+			memcpy(*creds, CMSG_DATA(cmsg), sizeof(struct ucred));
+			break;
+		}
+	}
+
+	free(msg.msg_control);
+	return n;
+
+abort:
+	free(msg.msg_control);
+	free(*buf);
+	return 0;
+}
+
+#define NL_CB_CALL(cb, type, msg) \
+do { \
+	err = nl_cb_call(cb, type, msg); \
+	switch (err) { \
+	case NL_OK: \
+		err = 0; \
+		break; \
+	case NL_SKIP: \
+		goto skip; \
+	case NL_STOP: \
+		goto stop; \
+	default: \
+		goto out; \
+	} \
+} while (0)
+
+static int recvmsgs(struct nl_sock *sk, struct nl_cb *cb)
+{
+	int n, err = 0, multipart = 0;
+	unsigned char *buf = NULL;
+	struct nlmsghdr *hdr;
+	struct sockaddr_nl nla = {0};
+	struct nl_msg *msg = NULL;
+	struct ucred *creds = NULL;
+
+continue_reading:
+	NL_DBG(3, "Attempting to read from %p\n", sk);
+	if (cb->cb_recv_ow)
+		n = cb->cb_recv_ow(sk, &nla, &buf, &creds);
+	else
+		n = nl_recv(sk, &nla, &buf, &creds);
+
+	if (n <= 0)
+		return n;
+
+	NL_DBG(3, "recvmsgs(%p): Read %d bytes\n", sk, n);
+
+	hdr = (struct nlmsghdr *) buf;
+	while (nlmsg_ok(hdr, n)) {
+		NL_DBG(3, "recgmsgs(%p): Processing valid message...\n", sk);
+
+		nlmsg_free(msg);
+		msg = nlmsg_convert(hdr);
+		if (!msg) {
+			err = -NLE_NOMEM;
+			goto out;
+		}
+
+		nlmsg_set_proto(msg, sk->s_proto);
+		nlmsg_set_src(msg, &nla);
+		if (creds)
+			nlmsg_set_creds(msg, creds);
+
+		/* Raw callback is the first, it gives the most control
+		 * to the user and he can do his very own parsing. */
+		if (cb->cb_set[NL_CB_MSG_IN])
+			NL_CB_CALL(cb, NL_CB_MSG_IN, msg);
+
+		/* Sequence number checking. The check may be done by
+		 * the user, otherwise a very simple check is applied
+		 * enforcing strict ordering */
+		if (cb->cb_set[NL_CB_SEQ_CHECK])
+			NL_CB_CALL(cb, NL_CB_SEQ_CHECK, msg);
+		else if (hdr->nlmsg_seq != sk->s_seq_expect) {
+			if (cb->cb_set[NL_CB_INVALID])
+				NL_CB_CALL(cb, NL_CB_INVALID, msg);
+			else {
+				err = -NLE_SEQ_MISMATCH;
+				goto out;
+			}
+		}
+
+		if (hdr->nlmsg_type == NLMSG_DONE ||
+		    hdr->nlmsg_type == NLMSG_ERROR ||
+		    hdr->nlmsg_type == NLMSG_NOOP ||
+		    hdr->nlmsg_type == NLMSG_OVERRUN) {
+			/* We can't check for !NLM_F_MULTI since some netlink
+			 * users in the kernel are broken. */
+			sk->s_seq_expect++;
+			NL_DBG(3, "recvmsgs(%p): Increased expected " \
+			       "sequence number to %d\n",
+			       sk, sk->s_seq_expect);
+		}
+
+		if (hdr->nlmsg_flags & NLM_F_MULTI)
+			multipart = 1;
+	
+		/* Other side wishes to see an ack for this message */
+		if (hdr->nlmsg_flags & NLM_F_ACK) {
+			if (cb->cb_set[NL_CB_SEND_ACK])
+				NL_CB_CALL(cb, NL_CB_SEND_ACK, msg);
+			else {
+				/* FIXME: implement */
+			}
+		}
+
+		/* messages terminates a multpart message, this is
+		 * usually the end of a message and therefore we slip
+		 * out of the loop by default. the user may overrule
+		 * this action by skipping this packet. */
+		if (hdr->nlmsg_type == NLMSG_DONE) {
+			multipart = 0;
+			if (cb->cb_set[NL_CB_FINISH])
+				NL_CB_CALL(cb, NL_CB_FINISH, msg);
+		}
+
+		/* Message to be ignored, the default action is to
+		 * skip this message if no callback is specified. The
+		 * user may overrule this action by returning
+		 * NL_PROCEED. */
+		else if (hdr->nlmsg_type == NLMSG_NOOP) {
+			if (cb->cb_set[NL_CB_SKIPPED])
+				NL_CB_CALL(cb, NL_CB_SKIPPED, msg);
+			else
+				goto skip;
+		}
+
+		/* Data got lost, report back to user. The default action is to
+		 * quit parsing. The user may overrule this action by retuning
+		 * NL_SKIP or NL_PROCEED (dangerous) */
+		else if (hdr->nlmsg_type == NLMSG_OVERRUN) {
+			if (cb->cb_set[NL_CB_OVERRUN])
+				NL_CB_CALL(cb, NL_CB_OVERRUN, msg);
+			else {
+				err = -NLE_MSG_OVERFLOW;
+				goto out;
+			}
+		}
+
+		/* Message carries a nlmsgerr */
+		else if (hdr->nlmsg_type == NLMSG_ERROR) {
+			struct nlmsgerr *e = nlmsg_data(hdr);
+
+			if (hdr->nlmsg_len < nlmsg_msg_size(sizeof(*e))) {
+				/* Truncated error message, the default action
+				 * is to stop parsing. The user may overrule
+				 * this action by returning NL_SKIP or
+				 * NL_PROCEED (dangerous) */
+				if (cb->cb_set[NL_CB_INVALID])
+					NL_CB_CALL(cb, NL_CB_INVALID, msg);
+				else {
+					err = -NLE_MSG_TRUNC;
+					goto out;
+				}
+			} else if (e->error) {
+				/* Error message reported back from kernel. */
+				if (cb->cb_err) {
+					err = cb->cb_err(&nla, e,
+							   cb->cb_err_arg);
+					if (err < 0)
+						goto out;
+					else if (err == NL_SKIP)
+						goto skip;
+					else if (err == NL_STOP) {
+						err = -nl_syserr2nlerr(e->error);
+						goto out;
+					}
+				} else {
+					err = -nl_syserr2nlerr(e->error);
+					goto out;
+				}
+			} else if (cb->cb_set[NL_CB_ACK])
+				NL_CB_CALL(cb, NL_CB_ACK, msg);
+		} else {
+			/* Valid message (not checking for MULTIPART bit to
+			 * get along with broken kernels. NL_SKIP has no
+			 * effect on this.  */
+			if (cb->cb_set[NL_CB_VALID])
+				NL_CB_CALL(cb, NL_CB_VALID, msg);
+		}
+skip:
+		err = 0;
+		hdr = nlmsg_next(hdr, &n);
+	}
+	
+	nlmsg_free(msg);
+	free(buf);
+	free(creds);
+	buf = NULL;
+	msg = NULL;
+	creds = NULL;
+
+	if (multipart) {
+		/* Multipart message not yet complete, continue reading */
+		goto continue_reading;
+	}
+stop:
+	err = 0;
+out:
+	nlmsg_free(msg);
+	free(buf);
+	free(creds);
+
+	return err;
+}
+
+/**
+ * Receive a set of messages from a netlink socket.
+ * @arg sk		Netlink socket.
+ * @arg cb		set of callbacks to control behaviour.
+ *
+ * Repeatedly calls nl_recv() or the respective replacement if provided
+ * by the application (see nl_cb_overwrite_recv()) and parses the
+ * received data as netlink messages. Stops reading if one of the
+ * callbacks returns NL_STOP or nl_recv returns either 0 or a negative error code.
+ *
+ * A non-blocking sockets causes the function to return immediately if
+ * no data is available.
+ *
+ * @return 0 on success or a negative error code from nl_recv().
+ */
+int nl_recvmsgs(struct nl_sock *sk, struct nl_cb *cb)
+{
+	if (cb->cb_recvmsgs_ow)
+		return cb->cb_recvmsgs_ow(sk, cb);
+	else
+		return recvmsgs(sk, cb);
+}
+
+
+static int ack_wait_handler(struct nl_msg *msg, void *arg)
+{
+	return NL_STOP;
+}
+
+/**
+ * Wait for ACK.
+ * @arg sk		Netlink socket.
+ * @pre The netlink socket must be in blocking state.
+ *
+ * Waits until an ACK is received for the latest not yet acknowledged
+ * netlink message.
+ */
+int nl_wait_for_ack(struct nl_sock *sk)
+{
+	int err;
+	struct nl_cb *cb;
+
+	cb = nl_cb_clone(sk->s_cb);
+	if (cb == NULL)
+		return -NLE_NOMEM;
+
+	nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, ack_wait_handler, NULL);
+	err = nl_recvmsgs(sk, cb);
+	nl_cb_put(cb);
+
+	return err;
+}
+
+/** @} */
+
+/** @} */