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lib: Extract from devlink/mnlg a helper, mnlu_socket_recv_run() 

Receiving a message in libmnl is a somewhat involved operation. Devlink's
mnlg library has an implementation that is going to be handy for other
tools as well. Extract it into a new helper.

Signed-off-by: Petr Machata <me@pmachata.org>
Signed-off-by: David Ahern <dsahern@gmail.com>
This commit is contained in:
Petr Machata 2020-11-12 23:24:43 +01:00 committed by David Ahern
parent dd78dfc7be
commit 6dd778e837
3 changed files with 65 additions and 54 deletions
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56
devlink/mnlg.c
View File

@ -28,7 +28,6 @@ struct mnlg_socket {
uint32_t id;
uint8_t version;
unsigned int seq;
unsigned int portid;
};
static struct nlmsghdr *__mnlg_msg_prepare(struct mnlg_socket *nlg, uint8_t cmd,
@ -57,61 +56,10 @@ int mnlg_socket_send(struct mnlg_socket *nlg, const struct nlmsghdr *nlh)
return mnl_socket_sendto(nlg->nl, nlh, nlh->nlmsg_len);
}
static int mnlg_cb_noop(const struct nlmsghdr *nlh, void *data)
{
return MNL_CB_OK;
}
static int mnlg_cb_error(const struct nlmsghdr *nlh, void *data)
{
const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh);
/* Netlink subsystems returns the errno value with different signess */
if (err->error < 0)
errno = -err->error;
else
errno = err->error;
if (nl_dump_ext_ack(nlh, NULL))
return MNL_CB_ERROR;
return err->error == 0 ? MNL_CB_STOP : MNL_CB_ERROR;
}
static int mnlg_cb_stop(const struct nlmsghdr *nlh, void *data)
{
int len = *(int *)NLMSG_DATA(nlh);
if (len < 0) {
errno = -len;
nl_dump_ext_ack_done(nlh, len);
return MNL_CB_ERROR;
}
return MNL_CB_STOP;
}
static mnl_cb_t mnlg_cb_array[NLMSG_MIN_TYPE] = {
[NLMSG_NOOP] = mnlg_cb_noop,
[NLMSG_ERROR] = mnlg_cb_error,
[NLMSG_DONE] = mnlg_cb_stop,
[NLMSG_OVERRUN] = mnlg_cb_noop,
};
int mnlg_socket_recv_run(struct mnlg_socket *nlg, mnl_cb_t data_cb, void *data)
{
int err;
do {
err = mnl_socket_recvfrom(nlg->nl, nlg->buf,
MNL_SOCKET_BUFFER_SIZE);
if (err <= 0)
break;
err = mnl_cb_run2(nlg->buf, err, nlg->seq, nlg->portid,
data_cb, data, mnlg_cb_array,
ARRAY_SIZE(mnlg_cb_array));
} while (err > 0);
return err;
return mnlu_socket_recv_run(nlg->nl, nlg->seq, nlg->buf, MNL_SOCKET_BUFFER_SIZE,
data_cb, data);
}
struct group_info {

2
include/mnl_utils.h
View File

@ -5,5 +5,7 @@
struct mnl_socket *mnlu_socket_open(int bus);
struct nlmsghdr *mnlu_msg_prepare(void *buf, uint32_t nlmsg_type, uint16_t flags,
void *extra_header, size_t extra_header_size);
int mnlu_socket_recv_run(struct mnl_socket *nl, unsigned int seq, void *buf, size_t buf_size,
mnl_cb_t cb, void *data);
#endif /* __MNL_UTILS_H__ */

61
lib/mnl_utils.c
View File

@ -3,11 +3,14 @@
* mnl_utils.c Helpers for working with libmnl.
*/
#include <errno.h>
#include <string.h>
#include <time.h>
#include <libmnl/libmnl.h>
#include "libnetlink.h"
#include "mnl_utils.h"
#include "utils.h"
struct mnl_socket *mnlu_socket_open(int bus)
{
@ -47,3 +50,61 @@ struct nlmsghdr *mnlu_msg_prepare(void *buf, uint32_t nlmsg_type, uint16_t flags
return nlh;
}
static int mnlu_cb_noop(const struct nlmsghdr *nlh, void *data)
{
return MNL_CB_OK;
}
static int mnlu_cb_error(const struct nlmsghdr *nlh, void *data)
{
const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh);
/* Netlink subsystems returns the errno value with different signess */
if (err->error < 0)
errno = -err->error;
else
errno = err->error;
if (nl_dump_ext_ack(nlh, NULL))
return MNL_CB_ERROR;
return err->error == 0 ? MNL_CB_STOP : MNL_CB_ERROR;
}
static int mnlu_cb_stop(const struct nlmsghdr *nlh, void *data)
{
int len = *(int *)NLMSG_DATA(nlh);
if (len < 0) {
errno = -len;
nl_dump_ext_ack_done(nlh, len);
return MNL_CB_ERROR;
}
return MNL_CB_STOP;
}
static mnl_cb_t mnlu_cb_array[NLMSG_MIN_TYPE] = {
[NLMSG_NOOP] = mnlu_cb_noop,
[NLMSG_ERROR] = mnlu_cb_error,
[NLMSG_DONE] = mnlu_cb_stop,
[NLMSG_OVERRUN] = mnlu_cb_noop,
};
int mnlu_socket_recv_run(struct mnl_socket *nl, unsigned int seq, void *buf, size_t buf_size,
mnl_cb_t cb, void *data)
{
unsigned int portid = mnl_socket_get_portid(nl);
int err;
do {
err = mnl_socket_recvfrom(nl, buf, buf_size);
if (err <= 0)
break;
err = mnl_cb_run2(buf, err, seq, portid,
cb, data, mnlu_cb_array,
ARRAY_SIZE(mnlu_cb_array));
} while (err > 0);
return err;
}