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utils: Add generic socket helpers

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Subsequent patch needs to
(a) query and use socket family
(b) send/receive messages using this family

Hence add helper routines to open, close, query family and to perform
send receive operations.

Signed-off-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: David Ahern <dsahern@kernel.org>
This commit is contained in:
Parav Pandit 2021-02-10 20:34:43 +02:00 committed by David Ahern
parent bd3709c3a7
commit b822275ad8
2 changed files with 137 additions and 0 deletions
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16
include/mnl_utils.h
View File

@ -2,6 +2,22 @@
#ifndef __MNL_UTILS_H__
#define __MNL_UTILS_H__ 1
struct mnlu_gen_socket {
struct mnl_socket *nl;
char *buf;
uint32_t family;
unsigned int seq;
uint8_t version;
};
int mnlu_gen_socket_open(struct mnlu_gen_socket *nlg, const char *family_name,
uint8_t version);
void mnlu_gen_socket_close(struct mnlu_gen_socket *nlg);
struct nlmsghdr *mnlu_gen_socket_cmd_prepare(struct mnlu_gen_socket *nlg,
uint8_t cmd, uint16_t flags);
int mnlu_gen_socket_sndrcv(struct mnlu_gen_socket *nlg, const struct nlmsghdr *nlh,
mnl_cb_t data_cb, void *data);
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);

121
lib/mnl_utils.c
View File

@ -7,6 +7,7 @@
#include <string.h>
#include <time.h>
#include <libmnl/libmnl.h>
#include <linux/genetlink.h>
#include "libnetlink.h"
#include "mnl_utils.h"
@ -108,3 +109,123 @@ int mnlu_socket_recv_run(struct mnl_socket *nl, unsigned int seq, void *buf, siz
return err;
}
static int get_family_id_attr_cb(const struct nlattr *attr, void *data)
{
int type = mnl_attr_get_type(attr);
const struct nlattr **tb = data;
if (mnl_attr_type_valid(attr, CTRL_ATTR_MAX) < 0)
return MNL_CB_ERROR;
if (type == CTRL_ATTR_FAMILY_ID &&
mnl_attr_validate(attr, MNL_TYPE_U16) < 0)
return MNL_CB_ERROR;
tb[type] = attr;
return MNL_CB_OK;
}
static int get_family_id_cb(const struct nlmsghdr *nlh, void *data)
{
struct genlmsghdr *genl = mnl_nlmsg_get_payload(nlh);
struct nlattr *tb[CTRL_ATTR_MAX + 1] = {};
uint32_t *p_id = data;
mnl_attr_parse(nlh, sizeof(*genl), get_family_id_attr_cb, tb);
if (!tb[CTRL_ATTR_FAMILY_ID])
return MNL_CB_ERROR;
*p_id = mnl_attr_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
return MNL_CB_OK;
}
static int family_get(struct mnlu_gen_socket *nlg, const char *family_name)
{
struct genlmsghdr hdr = {};
struct nlmsghdr *nlh;
int err;
hdr.cmd = CTRL_CMD_GETFAMILY;
hdr.version = 0x1;
nlh = mnlu_msg_prepare(nlg->buf, GENL_ID_CTRL,
NLM_F_REQUEST | NLM_F_ACK,
&hdr, sizeof(hdr));
mnl_attr_put_strz(nlh, CTRL_ATTR_FAMILY_NAME, family_name);
err = mnl_socket_sendto(nlg->nl, nlh, nlh->nlmsg_len);
if (err < 0)
return err;
err = mnlu_socket_recv_run(nlg->nl, nlh->nlmsg_seq, nlg->buf,
MNL_SOCKET_BUFFER_SIZE,
get_family_id_cb, &nlg->family);
return err;
}
int mnlu_gen_socket_open(struct mnlu_gen_socket *nlg, const char *family_name,
uint8_t version)
{
int err;
nlg->buf = malloc(MNL_SOCKET_BUFFER_SIZE);
if (!nlg->buf)
goto err_buf_alloc;
nlg->nl = mnlu_socket_open(NETLINK_GENERIC);
if (!nlg->nl)
goto err_socket_open;
err = family_get(nlg, family_name);
if (err)
goto err_socket;
return 0;
err_socket:
mnl_socket_close(nlg->nl);
err_socket_open:
free(nlg->buf);
err_buf_alloc:
return -1;
}
void mnlu_gen_socket_close(struct mnlu_gen_socket *nlg)
{
mnl_socket_close(nlg->nl);
free(nlg->buf);
}
struct nlmsghdr *mnlu_gen_socket_cmd_prepare(struct mnlu_gen_socket *nlg,
uint8_t cmd, uint16_t flags)
{
struct genlmsghdr hdr = {};
struct nlmsghdr *nlh;
hdr.cmd = cmd;
hdr.version = nlg->version;
nlh = mnlu_msg_prepare(nlg->buf, nlg->family, flags, &hdr, sizeof(hdr));
nlg->seq = nlh->nlmsg_seq;
return nlh;
}
int mnlu_gen_socket_sndrcv(struct mnlu_gen_socket *nlg, const struct nlmsghdr *nlh,
mnl_cb_t data_cb, void *data)
{
int err;
err = mnl_socket_sendto(nlg->nl, nlh, nlh->nlmsg_len);
if (err < 0) {
perror("Failed to send data");
return -errno;
}
err = mnlu_socket_recv_run(nlg->nl, nlh->nlmsg_seq, nlg->buf,
MNL_SOCKET_BUFFER_SIZE,
data_cb, data);
if (err < 0) {
fprintf(stderr, "kernel answers: %s\n", strerror(errno));
return -errno;
}
return 0;
}