我遇到类似的问题: Netlink sockets and libnl - nl_recvmsgs_default returning -16 (EBUSY)
但nl_recvmsgs_defaul()
返回此错误值-22(NLE_MSGTYPE_NOSUPPORT)。
有谁知道我为什么会收到这个错误?
以下是示例程序:
内核:
enum {
DOC_EXMPL_A_UNSPEC,
DOC_EXMPL_A_MSG,
__DOC_EXMPL_A_MAX,
};
#define DOC_EXMPL_A_MAX (__DOC_EXMPL_A_MAX - 1)
#define VERSION_NR 1
static struct genl_family doc_exmpl_gnl_family = {
.id = GENL_ID_GENERATE,
.hdrsize = 0,
.name = "CONTROL_EXMPL",
.version = VERSION_NR,
};
enum {
DOC_EXMPL_C_UNSPEC,
DOC_EXMPL_C_ECHO,
__DOC_EXMPL_C_MAX,
};
#define DOC_EXMPL_C_MAX (__DOC_EXMPL_C_MAX - 1)
int doc_exmpl_echo(struct sk_buff *skb_2, struct genl_info *info)
{
struct sk_buff *skb;
struct nlattr *na, *pos;
int len, rem, type, rc;
char * mydata;
void *msg_head;
if (info == NULL)
goto out;
len = nlmsg_attrlen(info->nlhdr, GENL_HDRLEN);
na = nlmsg_attrdata(info->nlhdr, GENL_HDRLEN);
printk(KERN_DEBUG "len1: %d, sizeof: %d ,len: %d", nlmsg_len(info->nlhdr),
GENL_HDRLEN, len);
nla_for_each_attr(pos, na, len, rem) {
type = nla_type(pos);
mydata = (char *) nla_data(pos);
printk(KERN_DEBUG "Type: %d", type);
if (mydata != NULL)
printk(KERN_DEBUG "Data: %s", mydata);
}
skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
if (skb == NULL)
goto out;
msg_head = genlmsg_put(skb, 0, info->snd_seq+1, &doc_exmpl_gnl_family, 0, DOC_EXMPL_C_ECHO);
if (msg_head == NULL) {
rc = -ENOMEM;
goto out;
}
rc = nla_put_u8(skb, DOC_EXMPL_A_MSG, 8);
if (rc != 0)
goto out;
/* finalize the message */
genlmsg_end(skb, msg_head);
//rc = genlmsg_unicast(skb,info->snd_pid );
rc = genlmsg_unicast(genl_info_net(info), skb,info->snd_pid);
if (rc != 0)
goto out;
printk(KERN_DEBUG "End");
return 0;
out:
printk("an error occured in doc_exmpl_echo:\n");
return 0;
}
struct genl_ops doc_exmpl_gnl_ops_echo = {
.cmd = DOC_EXMPL_C_ECHO,
.flags = 0,
.policy = NULL,
.doit = doc_exmpl_echo,
.dumpit = NULL,
};
用户空间代码
#include <stdio.h>
#include <stdlib.h>
#include <netlink/netlink.h>
#include <netlink/genl/genl.h>
#include <netlink/genl/ctrl.h>
#include <netlink/socket.h>
#include <netlink/msg.h>
#include <net/if.h>
static int expectedId;
static int nlCallback(struct nl_msg* msg, void* arg)
{
struct nlmsghdr* ret_hdr = nlmsg_hdr(msg);
struct nlattr *tb_msg[2 + 1];
char *str;
if (ret_hdr->nlmsg_type != expectedId)
{
// what is this??
return NL_STOP;
}
struct genlmsghdr *gnlh = (struct genlmsghdr*) nlmsg_data(ret_hdr);
nla_parse(tb_msg, 2, genlmsg_attrdata(gnlh, 0),
genlmsg_attrlen(gnlh, 0), NULL);
if (tb_msg[1]) {
str = nla_get_string(tb_msg[1]);
printf("str: %s", str);
}
return 0;
}
int main(int argc, char **argv) {
int cmd, rc;
struct nl_handle *sk;
struct nl_msg *msg;
//allocate socket
sk = nl_handle_alloc();
//connect to generic netlink
genl_connect(sk);
//find the nl80211 driver ID
expectedId = genl_ctrl_resolve(sk, "CONTROL_EXMPL");
//allocate a message
msg = nlmsg_alloc();
cmd = 1;
int flags = 0;
// setup the message
genlmsg_put(msg, NL_AUTO_PID, NL_AUTO_SEQ, expectedId, 0, NLM_F_REQUEST, cmd, 1);
NLA_PUT_STRING(msg, 3, "Hello test");
nl_send_auto_complete(sk, msg);
nl_socket_modify_cb(sk, NL_CB_VALID, NL_CB_CUSTOM,
nlCallback, NULL);
rc = nl_recvmsgs_default(sk);
printf("rc = %d \n", rc);
nlmsg_free(msg);
return 0;
nla_put_failure:
nlmsg_free(msg);
return 1;
}
答案 0 :(得分:1)
好的,我发现了问题。
我在内核代码中有错误的序列号,它应该是:
genlmsg_put(skb,0,info-&gt; snd_seq,&amp; doc_exmpl_gnl_family,0,DOC_EXMPL_C_ECHO);
与此问题相同:Netlink sockets and libnl - nl_recvmsgs_default returning -16 (EBUSY)但我还有其他错误。