/**
* mnl_nlmsg_fprintf - print netlink message to file
* \param fd pointer to file type
* \param data pointer to the buffer that contains messages to be printed
* \param datalen length of data stored in the buffer
* \param extra_header_size size of the extra header (if any)
*
* This function prints the netlink header to a file handle.
* It may be useful for debugging purposes. One example of the output
* is the following:
*
*\verbatim
---------------- ------------------
| 0000000040 | | message length |
| 00016 | R-A- | | type | flags |
| 1289148991 | | sequence number|
| 0000000000 | | port ID |
---------------- ------------------
| 00 00 00 00 | | extra header |
| 00 00 00 00 | | extra header |
| 01 00 00 00 | | extra header |
| 01 00 00 00 | | extra header |
|00008|--|00003| |len |flags| type|
| 65 74 68 30 | | data | e t h 0
---------------- ------------------
\endverbatim
*
* This example above shows the netlink message that is send to kernel-space
* to set up the link interface eth0. The netlink and attribute header data
* are displayed in base 10 whereas the extra header and the attribute payload
* are expressed in base 16. The possible flags in the netlink header are:
*
* - R, that indicates that NLM_F_REQUEST is set.
* - M, that indicates that NLM_F_MULTI is set.
* - A, that indicates that NLM_F_ACK is set.
* - E, that indicates that NLM_F_ECHO is set.
*
* The lack of one flag is displayed with '-'. On the other hand, the possible
* attribute flags available are:
*
* - N, that indicates that NLA_F_NESTED is set.
* - B, that indicates that NLA_F_NET_BYTEORDER is set.
*/
void
mnl_nlmsg_fprintf(FILE *fd, const void *data, size_t datalen,
size_t extra_header_size)
{
const struct nlmsghdr *nlh = data;
int len = datalen;
while (mnl_nlmsg_ok(nlh, len)) {
mnl_nlmsg_fprintf_header(fd, nlh);
mnl_nlmsg_fprintf_payload(fd, nlh, extra_header_size);
nlh = mnl_nlmsg_next(nlh, &len);
}
}
//libuv dgram socket callback. Only checks if message is of right type and then
//call function for parsing message
static void neat_linux_nl_recv(uv_udp_t *handle, ssize_t nread,
const uv_buf_t *buf, const struct sockaddr *addr, unsigned int flags)
{
struct neat_ctx *nc = (struct neat_ctx*) handle->data;
struct nlmsghdr *nl_hdr = (struct nlmsghdr*) buf->base;
//We don't need any check here, we don't read more than 8192 bytes in one go
int numbytes = (int) nread;
while (mnl_nlmsg_ok(nl_hdr, numbytes)) {
if (nl_hdr->nlmsg_type == RTM_NEWADDR ||
nl_hdr->nlmsg_type == RTM_DELADDR)
neat_linux_handle_addr(nc, nl_hdr);
nl_hdr = mnl_nlmsg_next(nl_hdr, &numbytes);
}
}
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;
}