Repo created

external/nflog/callback.c

@@ -0,0 +1,161 @@
+/*
+ * (C) 2008-2010 by Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * This program 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; either version 2.1 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <errno.h>
+#include <libmnl/libmnl.h>
+#include "internal.h"
+
+static int mnl_cb_noop(const struct nlmsghdr *nlh, void *data)
+{
+	return MNL_CB_OK;
+}
+
+static int mnl_cb_error(const struct nlmsghdr *nlh, void *data)
+{
+	const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh);
+
+	if (nlh->nlmsg_len < mnl_nlmsg_size(sizeof(struct nlmsgerr))) {
+		errno = EBADMSG; 
+		return MNL_CB_ERROR;
+	}
+	/* Netlink subsystems returns the errno value with different signess */
+	if (err->error < 0)
+		errno = -err->error;
+	else
+		errno = err->error;
+
+	return err->error == 0 ? MNL_CB_STOP : MNL_CB_ERROR;
+}
+
+static int mnl_cb_stop(const struct nlmsghdr *nlh, void *data)
+{
+	return MNL_CB_STOP;
+}
+
+static const mnl_cb_t default_cb_array[NLMSG_MIN_TYPE] = {
+	[NLMSG_NOOP]	= mnl_cb_noop,
+	[NLMSG_ERROR]	= mnl_cb_error,
+	[NLMSG_DONE]	= mnl_cb_stop,
+	[NLMSG_OVERRUN]	= mnl_cb_noop,
+};
+
+static inline int
+__mnl_cb_run(const void *buf, size_t numbytes, unsigned int seq,
+	     unsigned int portid, mnl_cb_t cb_data, void *data,
+	     mnl_cb_t *cb_ctl_array, unsigned int cb_ctl_array_len)
+{
+	int ret = MNL_CB_OK, len = numbytes;
+	const struct nlmsghdr *nlh = buf;
+
+	while (mnl_nlmsg_ok(nlh, len)) {
+		/* check message source */
+		if (!mnl_nlmsg_portid_ok(nlh, portid)) {
+			errno = ESRCH;
+			return -1;
+		}
+		/* perform sequence tracking */
+		if (!mnl_nlmsg_seq_ok(nlh, seq)) {
+			errno = EPROTO;
+			return -1;
+		}
+
+		/* netlink data message handling */
+		if (nlh->nlmsg_type >= NLMSG_MIN_TYPE) { 
+			if (cb_data){
+				ret = cb_data(nlh, data);
+				if (ret <= MNL_CB_STOP)
+					goto out;
+			}
+		} else if (nlh->nlmsg_type < cb_ctl_array_len) {
+			if (cb_ctl_array && cb_ctl_array[nlh->nlmsg_type]) {
+				ret = cb_ctl_array[nlh->nlmsg_type](nlh, data);
+				if (ret <= MNL_CB_STOP)
+					goto out;
+			}
+		} else if (default_cb_array[nlh->nlmsg_type]) {
+			ret = default_cb_array[nlh->nlmsg_type](nlh, data);
+			if (ret <= MNL_CB_STOP)
+				goto out;
+		}
+		nlh = mnl_nlmsg_next(nlh, &len);
+	}
+out:
+	return ret;
+}
+
+/**
+ * \defgroup callback Callback helpers
+ * @{
+ */
+
+/**
+ * mnl_cb_run2 - callback runqueue for netlink messages
+ * \param buf buffer that contains the netlink messages
+ * \param numbytes number of bytes stored in the buffer
+ * \param seq sequence number that we expect to receive
+ * \param portid Netlink PortID that we expect to receive
+ * \param cb_data callback handler for data messages
+ * \param data pointer to data that will be passed to the data callback handler
+ * \param cb_ctl_array array of custom callback handlers from control messages
+ * \param cb_ctl_array_len array length of custom control callback handlers
+ *
+ * You can set the cb_ctl_array to NULL if you want to use the default control
+ * callback handlers, in that case, the parameter cb_ctl_array_len is not
+ * checked.
+ *
+ * Your callback may return three possible values:
+ * 	- MNL_CB_ERROR (<=-1): an error has occurred. Stop callback runqueue.
+ * 	- MNL_CB_STOP (=0): stop callback runqueue.
+ * 	- MNL_CB_OK (>=1): no problem has occurred.
+ *
+ * This function propagates the callback return value. On error, it returns
+ * -1 and errno is explicitly set. If the portID is not the expected, errno
+ * is set to ESRCH. If the sequence number is not the expected, errno is set
+ * to EPROTO.
+ */
+int
+mnl_cb_run2(const void *buf, size_t numbytes, unsigned int seq,
+	    unsigned int portid, mnl_cb_t cb_data, void *data,
+	    mnl_cb_t *cb_ctl_array, unsigned int cb_ctl_array_len)
+{
+	return __mnl_cb_run(buf, numbytes, seq, portid, cb_data, data,
+			    cb_ctl_array, cb_ctl_array_len);
+}
+EXPORT_SYMBOL(mnl_cb_run2);
+
+/**
+ * mnl_cb_run - callback runqueue for netlink messages (simplified version)
+ * \param buf buffer that contains the netlink messages
+ * \param numbytes number of bytes stored in the buffer
+ * \param seq sequence number that we expect to receive
+ * \param portid Netlink PortID that we expect to receive
+ * \param cb_data callback handler for data messages
+ * \param data pointer to data that will be passed to the data callback handler
+ *
+ * This function is like mnl_cb_run2() but it does not allow you to set
+ * the control callback handlers.
+ *
+ * Your callback may return three possible values:
+ * 	- MNL_CB_ERROR (<=-1): an error has occurred. Stop callback runqueue.
+ * 	- MNL_CB_STOP (=0): stop callback runqueue.
+ * 	- MNL_CB_OK (>=1): no problems has occurred.
+ *
+ * This function propagates the callback return value.
+ */
+int
+mnl_cb_run(const void *buf, size_t numbytes, unsigned int seq,
+	   unsigned int portid, mnl_cb_t cb_data, void *data)
+{
+	return __mnl_cb_run(buf, numbytes, seq, portid, cb_data, data, NULL, 0);
+}
+EXPORT_SYMBOL(mnl_cb_run);
+
+/**
+ * @}
+ */