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/*
* (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;
}
/* dump was interrupted */
if (nlh->nlmsg_flags & NLM_F_DUMP_INTR) {
errno = EINTR;
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. If the dump was interrupted, errno is set to EINTR and you should
* request a new fresh dump again.
*/
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);
/**
* @}
*/
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