When I look at errors return by functions, I get error -3 on
netlink_broadcast, (maybe *no such process* regarding to kernel
source).
So the problems should comes from kernel code.
I have also tried under Debian, kernel 2.6.26, and what a surprise:
now, there is one more argument on netlink_kernel_create function.
So in 3 different kernels, 3 differents fonctions netlink_kernel_create...
Unfortunatly there are to many changements on kernel 2.6.26, and I
must keep working on kernel 2.6.18.
Regards,
Thierry
On Fri, Apr 10, 2009 at 10:12 AM, Thierry <chocapiiic.tiery@xxxxxxxxx> wrote:
> Hi,
>
> I have tried to change groupId, with different value, but there should
> be somethings wrong: the userspace prgm doesn't receive message.
> I would like to know if there is a plugin for tcpdump or an way of
> capture trafic on netlink socket, just like usual network socket in
> order to see were is my problem: in kernel space code or userspace
> code.
> My program code is attached, with english commit (sorry for last mail).
> I have also tried my code on differents kernel (redhat 4.4 with kernel
> 2.6.9-42.ELsmp, centos52 kernel 2.6.18-92.1.22).
>
> If there is other ways to send information from kernel space to user space...
> My aim is to capture data trafic from infiniband and dump trafic, for
> example in a netlink socket. Then I will be able with a userspace code
> to translate informations in .cap files.
> Thats why I think netlink_broadcast is a good idea.
>
> I will be always looking at kernelnewbie mailinglsit for several month,
>
> Regards,
>
> Thierry
>
>
>
> --------------
> kernel-level code
>
>
> #include <linux/config.h>
> #include <linux/socket.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> #include <linux/netlink.h>
> #include <net/sock.h>
>
> #define NETLINK_IB 24
> #define MAX_PAYLOAD 1024
> #define GROUP_IB 59
>
>
> static struct sock *nl_sk = NULL;
>
> static void nl_ib_data_ready (struct sock *sk, int len)
> {
> wake_up_interruptible(sk->sk_sleep);
> }
>
> static void netlink_ib_open()
> {
> struct sk_buff *skb = NULL;
> struct nlmsghdr *nlh = NULL;
> int err;
> u32 pid;
>
> //Socket_create
> nl_sk = netlink_kernel_create(NETLINK_IB, GROUP_IB, nl_ib_data_ready,
> THIS_MODULE);
>
> skb = alloc_skb(NLMSG_SPACE(MAX_PAYLOAD),GFP_KERNEL);
> nlh = (struct nlmsghdr *)skb->data;
>
> nlh->nlmsg_len = NLMSG_SPACE(MAX_PAYLOAD);
> nlh->nlmsg_pid = 0; //from kernel
> nlh->nlmsg_flags = 0;
>
> strcpy(NLMSG_DATA(nlh), "Message from kernel ");
> NETLINK_CB(skb).pid = 0;
> NETLINK_CB(skb).dst_pid = 0; //Multicast
> NETLINK_CB(skb).dst_group = GROUP_IB;
>
> //data send
> printk( KERN_ALERT "data sent\n");
> netlink_broadcast(nl_sk, skb, 0, GROUP_IB, GFP_KERNEL);
> sock_release(nl_sk->sk_socket);
> }
>
> static int __init netlink_ib_module_init(void)
> {
> printk(KERN_INFO "netlink_ib module: Init\n");
> netlink_ib_open();
> return 0;
> }
>
> static void __exit netlink_ib_module_exit(void)
> {
> printk(KERN_INFO "Unloading netlink_ib module\n");
> }
>
> MODULE_LICENSE("GPL");
> MODULE_DESCRIPTION("Kernel/User socket for IB support");
> module_init(netlink_ib_module_init);
> module_exit(netlink_ib_module_exit);
>
> ------------------
> userlevel code:
>
> #include <sys/socket.h>
> #include <linux/netlink.h>
> #define NETLINK_IB 24
> #define GROUP_IB 59
>
> #define MAX_PAYLOAD 1024
> struct sockaddr_nl src_addr, dst_addr;
> struct nlmsghdr *nlh = NULL;
> struct msghdr msg;
> struct iovec iov;
> int sock_fd;
>
>
> int main()
> {
> /* Socket create*/
> sock_fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_IB);
>
> memset(&src_addr, 0, sizeof(src_addr));
> src_addr.nl_family = AF_NETLINK;
> src_addr.nl_pid = getpid();
> src_addr.nl_groups = GROUP_IB; // Multicast
> bind(sock_fd, (struct sockaddr*)&src_addr, sizeof(src_addr));
>
> memset(&dst_addr, 0, sizeof(dst_addr));
> nlh = (struct nlhmsghdr *)malloc(NLMSG_SPACE(MAX_PAYLOAD));
> memset(nlh, 0, NLMSG_SPACE(MAX_PAYLOAD));
>
> iov.iov_base = (void *)nlh;
> iov.iov_len = nlh->nlmsg_len;
> msg.msg_name = (void *)&dst_addr;
> msg.msg_namelen = sizeof(dst_addr);
> msg.msg_iov = &iov;
> msg.msg_iovlen = 1;
>
> printf("Listenning on netlink socket...\n");
> recvmsg(sock_fd, &msg, 0);
> printf("Message received in userspace: %s\n", NLMSG_DATA(nlh));
> close(sock_fd);
>
> return 0;
>
> }
>
>
> -----------
>
>
> On Wed, Apr 8, 2009 at 5:51 PM, Sandeep K Sinha <sandeepksinha@xxxxxxxxx> wrote:
>> Milind can you help Thierry on this.
>>
>>
>> On Wed, Apr 8, 2009 at 7:14 PM, Thierry <chocapiiic.tiery@xxxxxxxxx> wrote:
>>> Hi,
>>>
>>> I want to use netlink socket between kernel and userspace in order to
>>> get some information from kernel code.
>>> I use netlink_broadcast function in order to send information to a
>>> specific group, and my user-level code connect to this socket with the
>>> correct groupId but doesn't receive anythings.
>>> Everythings works when I use netlink_unicast.
>>>
>>> I use centos5.2, kernel 2.6.18-92.1.22
>>>
>>> If someone can help me...
>>>
>>> Thierry
>>>
>>>
>>>
>>>
>>>
>>> ---------------------------
>>>
>>> kernel-code:
>>>
>>> #include <linux/config.h>
>>> #include <linux/socket.h>
>>> #include <linux/kernel.h>
>>> #include <linux/module.h>
>>> #include <linux/netlink.h>
>>> #include <net/sock.h>
>>> //#include <net/netlink.h>
>>>
>>> #define NETLINK_IB 24
>>> #define MAX_PAYLOAD 1024
>>> #define GROUP_IB 59
>>>
>>> static struct sock *nl_sk = NULL;
>>>
>>> static void nl_ib_data_ready (struct sock *sk, int len)
>>> {
>>> wake_up_interruptible(sk->sk_sleep);
>>> }
>>>
>>> static void netlink_ib_open()
>>> {
>>> struct sk_buff *skb = NULL;
>>> struct nlmsghdr *nlh = NULL;
>>> int err;
>>> u32 pid;
>>>
>>> //Creation de la netlink socket <=> socket()
>>> nl_sk = netlink_kernel_create(NETLINK_IB, GROUP_IB, nl_ib_data_ready,
>>> THIS_MODULE);
>>>
>>> skb = alloc_skb(NLMSG_SPACE(MAX_PAYLOAD),GFP_KERNEL);
>>> nlh = (struct nlmsghdr *)skb->data;
>>>
>>> nlh->nlmsg_len = NLMSG_SPACE(MAX_PAYLOAD);
>>> nlh->nlmsg_pid = 0; //Depuis le noyau
>>> nlh->nlmsg_flags = 0;
>>>
>>> strcpy(NLMSG_DATA(nlh), "Message du kernel =(");
>>> NETLINK_CB(skb).pid = 0;
>>> NETLINK_CB(skb).dst_pid = 0; //Multicast
>>> NETLINK_CB(skb).dst_group = GROUP_IB;
>>>
>>> //Envoi des donnees
>>> printk( KERN_ALERT "j'envoi els donnees\n");
>>> netlink_broadcast(nl_sk, skb, 0, GROUP_IB, GFP_KERNEL);
>>> sock_release(nl_sk->sk_socket);
>>> }
>>>
>>> static int __init netlink_ib_module_init(void)
>>> {
>>> printk(KERN_INFO "netlink_ib module: Initialisation de la Netlink Socket\n");
>>> netlink_ib_open();
>>> return 0;
>>> }
>>>
>>> static void __exit netlink_ib_module_exit(void)
>>> {
>>> printk(KERN_INFO "Dechargement de netlink_ib module\n");
>>> }
>>>
>>> MODULE_DESCRIPTION("Kernel/User socket for IB support");
>>> module_init(netlink_ib_module_init);
>>> module_exit(netlink_ib_module_exit);
>>>
>>> ----------------------------
>>>
>>> and the user-level code:
>>>
>>> #include <sys/socket.h>
>>> #include <linux/netlink.h>
>>> #define NETLINK_IB 24
>>> #define GROUP_IB 59
>>>
>>> #define MAX_PAYLOAD 1024
>>>
>>> struct sockaddr_nl src_addr, dst_addr;
>>> struct nlmsghdr *nlh = NULL;
>>> struct msghdr msg;
>>> struct iovec iov;
>>> int sock_fd;
>>>
>>>
>>> int main()
>>> {
>>> /* Ouverture de la socket Netlink*/
>>> sock_fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_IB);
>>>
>>> memset(&src_addr, 0, sizeof(src_addr));
>>> src_addr.nl_family = AF_NETLINK;
>>> src_addr.nl_pid = getpid();
>>> src_addr.nl_groups = GROUP_IB; // Multicast
>>> bind(sock_fd, (struct sockaddr*)&src_addr, sizeof(src_addr));
>>>
>>> memset(&dst_addr, 0, sizeof(dst_addr));
>>> nlh = (struct nlhmsghdr *)malloc(NLMSG_SPACE(MAX_PAYLOAD));
>>> memset(nlh, 0, NLMSG_SPACE(MAX_PAYLOAD));
>>>
>>> iov.iov_base = (void *)nlh;
>>> iov.iov_len = nlh->nlmsg_len;
>>> msg.msg_name = (void *)&dst_addr;
>>> msg.msg_namelen = sizeof(dst_addr);
>>> msg.msg_iov = &iov;
>>> msg.msg_iovlen = 1;
>>>
>>> printf("On ecoute...\n");
>>> /* On ecoute ce que le kernel renvoi */
>>> recvmsg(sock_fd, &msg, 0);
>>> printf("jai recu");
>>> char * truc = NLMSG_DATA(nlh);
>>> printf("Message recu dans lespace utilisateur: %s\n", truc);
>>> close(sock_fd);
>>>
>>> return 0;
>>>
>>> }
>>>
>>> --
>>> To unsubscribe from this list: send an email with
>>> "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx
>>> Please read the FAQ at http://kernelnewbies.org/FAQ
>>>
>>>
>>
>>
>>
>> --
>> Regards,
>> Sandeep.
>>
>>
>>
>>
>>
>>
>> “To learn is to change. Education is a process that changes the learner.”
>>
>
--
To unsubscribe from this list: send an email with
"unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx
Please read the FAQ at http://kernelnewbies.org/FAQ
