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| // gcc user_nl.c -lnl
//
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <poll.h>
#include <string.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <signal.h>
#include <asm/types.h>
//#include <linux/genetlink.h>
#include <netlink/socket.h>
#include <netlink/genl/genl.h>
#include <netlink/genl/family.h>
#include <netlink/genl/ctrl.h>
#include <netlink/msg.h>
#define MESSAGE_TO_KERNEL "Hello World from user space!!"
struct family_hdr {
int ff;
};
struct data_hdr {
int len;
int kk;
char str[0];
};
/* netlink attributes */
enum {
DOC_EXMPL_A_UNSPEC,
DOC_EXMPL_A_MSG,
DOC_EXMPL_A_MSG2,
__DOC_EXMPL_A_MAX,
};
#define DOC_EXMPL_A_MAX (__DOC_EXMPL_A_MAX - 1)
//copy from kernel driver genl_ops's cmd
enum {
DOC_EXMPL_C_UNSPEC,
DOC_EXMPL_C_ECHO,
__DOC_EXMPL_C_MAX,
};
#define DOC_EXMPL_C_MAX (__DOC_EXMPL_C_MAX - 1)
static int error_handler(struct sockaddr_nl *nla, struct nlmsgerr *err, void *arg)
{
int *ret = arg;
fprintf(stderr, "error\n");
*ret = err->error;
return NL_STOP;
}
static int finish_handler(struct nl_msg *msg, void *arg)
{
int *ret = arg;
*ret = 0;
fprintf(stderr, "finish\n");
return NL_SKIP;
}
static int ack_handler(struct nl_msg *msg, void *arg)
{
int *ret = arg;
*ret = 0;
fprintf(stderr, "ack\n");
return NL_STOP;
}
static int reply_handler(struct nl_msg *msg, void *arg)
{
struct nlattr *tb[DOC_EXMPL_A_MAX + 1] = {0};
struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
struct family_hdr *fhdr = genlmsg_attrdata(gnlh, 0);
struct data_hdr *hdr;
int rc, i;
int rcvlen;
rc = nla_parse(tb, DOC_EXMPL_A_MAX,
genlmsg_attrdata(gnlh, sizeof(struct family_hdr)),
genlmsg_attrlen(gnlh, sizeof(struct family_hdr)), NULL);
if (rc) {
printf("nla_parse err\n");
return NL_STOP;
}
for (i = 1; i <= DOC_EXMPL_A_MAX; i ++) {
rcvlen = nla_len(tb[i]);
hdr = (struct data_hdr*)nla_data(tb[i]);
printf("rcv: %d %d %d %d rcvlen=%d %s\n", i, fhdr->ff, hdr->len, hdr->kk, rcvlen, hdr->str);
}
return NL_OK;
}
static int test_genlink_nl(void)
{
struct nl_handle *nlsk;
int nlid, err, ret;
struct nl_msg *msg = NULL;
struct nl_cb *cb = NULL;
char cbdata[123], sss[123];
struct family_hdr *fhdr;
struct data_hdr *hdr = (struct data_hdr *)sss;
nlsk = nl_handle_alloc();
if (!nlsk) {
printf("nl_socket_alloc err\n");
return -1;
}
nl_set_buffer_size(nlsk, 8192, 8192);
if (genl_connect(nlsk)) {
printf("genl_connect err\n");
goto free_nlsk;
}
nlid = genl_ctrl_resolve(nlsk, "DOC_EXMPL");
if (nlid < 0) {
printf("genl_ctrl_resolve err\n");
goto free_nlsk;
}
msg = nlmsg_alloc();
if (!msg) {
printf("nlmsg_alloc err\n");
goto free_nlsk;
}
cb = nl_cb_alloc(NL_CB_DEFAULT);
if (!cb) {
printf("nl_cb_alloc err\n");
goto free_msg;
}
nl_socket_set_cb(nlsk, cb);
fhdr = (struct family_hdr *)genlmsg_put(msg, 0, 0, nlid, sizeof(struct family_hdr), 0, DOC_EXMPL_C_ECHO, 0);
if (!fhdr) {
printf("genlmsg_put err\n");
goto free_cb;
}
fhdr->ff = 111;
hdr->len = 123;
hdr->kk = 456;
strcpy(hdr->str, MESSAGE_TO_KERNEL);
ret = nla_put(msg, DOC_EXMPL_A_MSG, sizeof(struct data_hdr)+strlen(MESSAGE_TO_KERNEL), hdr);
if (ret < 0) {
printf("nla_put err\n");
goto free_cb;
}
hdr->len = 700;
hdr->kk = 800;
ret = nla_put(msg, DOC_EXMPL_A_MSG2, sizeof(struct data_hdr)+strlen(MESSAGE_TO_KERNEL), hdr);
if (ret < 0) {
printf("nla_put err2\n");
goto free_cb;
}
ret = nl_send_auto_complete(nlsk, msg);
if (ret < 0) {
printf("nl_send_auto_complete err\n");
goto free_cb;
}
err = 1;
nl_cb_err(cb, NL_CB_CUSTOM, error_handler, &err);
nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, finish_handler, &err);
nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, ack_handler, &err);
nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, reply_handler, &cbdata);
ret = nl_recvmsgs(nlsk, cb);
if (ret) {
printf("nl_recvmsgs err\n");
}
return err;
free_cb:
nl_cb_put(cb);
free_msg:
nlmsg_free(msg);
free_nlsk:
nl_handle_destroy(nlsk);
return -2;
}
int main(int argc, char *argv[])
{
return test_genlink_nl();
}
|
