Netlink

static struct nla_policy	ce_gw_genl_policy [CE_GW_A_MAX+1]
	Netlink Policy - Defines the Type for the Netlink Attributes. More...
static struct genl_family	ce_gw_genl_family
	Generic Netlink Family. More...
struct genl_ops	ce_gw_genl_ops_echo
	details of ce_gw_netlink_echo() More...
struct genl_ops	ce_gw_genl_ops_add
	details of ce_gw_netlink_add() More...
struct genl_ops	ce_gw_genl_ops_del
	details of ce_gw_netlink_del() More...
struct genl_ops	ce_gw_genl_ops_list
	details of ce_gw_netlink_list() More...
int	ce_gw_netlink_echo (struct sk_buff *skb_info, struct genl_info *info)
	Generic Netlink Command - Sends a massage back. More...
int	ce_gw_netlink_add (struct sk_buff *skb_info, struct genl_info *info)
	add a virtual ethernet device or a route More...
int	ce_gw_netlink_del (struct sk_buff *skb_info, struct genl_info *info)
	Deletes a device by name or a route by ID. More...
int	ce_gw_netlink_list (struct sk_buff *skb_info, struct genl_info *info)
	Send informations of one or more routes to userspace. More...
int	ce_gw_netlink_init (void)
	Must called once at module init. More...
void	ce_gw_netlink_exit (void)
	Must called once at module exit. More...

Detailed Description

Function Documentation

int ce_gw_netlink_add	(	struct sk_buff *	skb_info,
		struct genl_info *	info
	)

add a virtual ethernet device or a route

Parameters

skb_info	Netlink Socket Buffer with Message
info	Additional Netlink Information will be called by ce_gw_add() in userspace in cegwctl.

Has multiple netlink Attributes.

• CE_GW_A_SRC: The textual name of the device wich will be the src. Must be NULL if you want do add a device.
• CE_GW_A_DST: The textual name of the device wich will be the dst OR the name of the device, if you want to add a device.
• CE_GW_A_TYPE: The Type of the route. For adding dev some settings according to the type will be set.
• CE_GW_A_FLAGS: The Flags of the route. For adding dev some settings according to the type will be set. See netlink.h for the falgs.

Return values

0	on success
<0	on failure

Definition at line 216 of file ce_gw_netlink.c.

References CE_GW_A_DST, CE_GW_A_FLAGS, CE_GW_A_SRC, CE_GW_A_TYPE, ce_gw_create_route(), ce_gw_dev_create(), ce_gw_dev_free(), and ce_gw_dev_register().

{
    int err = 0;
    if (info == NULL) {
        err = -EINVAL;
        pr_err("ce_gw: info attribute is missing."\
               " No Massage received.\n");
        return err;
    }

    struct nlattr *nla_src = info->attrs[CE_GW_A_SRC];
    char *nla_src_data = (char *) nla_data(nla_src);

    struct nlattr *nla_dst = info->attrs[CE_GW_A_DST];
    char *nla_dst_data = (char *) nla_data(nla_dst);

    struct nlattr *nla_flags = info->attrs[CE_GW_A_FLAGS];
    u32 *nla_flags_data = (u32 *) nla_data(nla_flags);

    struct nlattr *nla_type = info->attrs[CE_GW_A_TYPE];
    u8 *nla_type_data = (u8 *) nla_data(nla_type);

    if (nla_src == NULL) { /* add dev is called in userspace */
        pr_info("ce_gw: add dev is called\n");
        struct net_device *dev;

        if (nla_dst == NULL ||
            nla_type == NULL || nla_flags == NULL) {
            pr_err("ce_gw: DST or TYPE is missing.\n");
            err = -ENODATA;
            goto ce_gw_add_error;
        }

        dev = ce_gw_dev_create(*nla_type_data, *nla_flags_data,
            nla_dst_data);
        if (dev == NULL) {
            pr_err("ce_gw_netlink: Device allocation failed.");
            err = -ENOMEM;
            goto ce_gw_add_error;
        }

        err = ce_gw_dev_register(dev);
        if (err != 0) {
            pr_err("ce_gw_netlink: Device registration failed.");
            ce_gw_dev_free(dev);
            goto ce_gw_add_error;
        }

    } else { /* add route is called in userspace*/
        if (nla_src == NULL || nla_dst == NULL ||
            nla_type == NULL || nla_flags == NULL) {
            pr_err("ce_gw: SRC or DST or TYPE is missing.\n");
            err = -ENODATA;
            goto ce_gw_add_error;
        }
        
            pr_info("ce_gw: Add : from %s to %s"
                    "(Type %d; Flags %d)\n", nla_src_data,
                    nla_dst_data, *nla_type_data, *nla_flags_data);

        /* get device index by their names */
        struct net_device *src_dev;
        src_dev = dev_get_by_name(&init_net, nla_src_data);
        if (src_dev == NULL) {
            err = -ENODEV;
            pr_err("ce_gw_netlink: src dev not found: %d\n", err);
            goto ce_gw_add_error;
        }
        int src_dev_ifindex = src_dev->ifindex;
        dev_put(src_dev);

        struct net_device *dst_dev;
        dst_dev = dev_get_by_name(&init_net, nla_dst_data);
        if (dst_dev == NULL) {
            err = -ENODEV;
            pr_err("ce_gw_netlink: dst dev not found: %d\n", err);
            goto ce_gw_add_error;
        }
        int dst_dev_ifindex = dst_dev->ifindex;
        dev_put(dst_dev);

        err = ce_gw_create_route(src_dev_ifindex, dst_dev_ifindex,
                                 *nla_type_data, *nla_flags_data);
        if (err != 0) {
            goto ce_gw_add_error;
        }
    }

ce_gw_add_error:
    /* TODO if you send two add messages A abd B in in very short
     * short distance (e.g. with option -b in userspace) than the
     * ACK Sequence number of Message B is the same of the Massage
     * A. So the ACK for Message B could not correct assign to
     * Message B in userspace and the userpace think there is an
     * error, but all is correct. This seems to be a bug in this
     * function of netlink */
    netlink_ack(skb_info, info->nlhdr, -err);
    return err;
}

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int ce_gw_netlink_del	(	struct sk_buff *	skb_info,
		struct genl_info *	info
	)

Deletes a device by name or a route by ID.

Parameters

skb_info	Netlink Socket Buffer with Message
info	Additional Netlink Information

Precondition

CE_GW_A_ID must be == 0 OR CE_GW_A_DST must be == NULL

will be called by ce_gw_add() in userspace in cegwctl.

Has multiple netlink Attributes:

• CE_GW_A_ID The id of the route you want to delete. CE_GW_A_DST must be NULL when you want to delete a route.
• CE_GW_A_DST The textual name of the virtual device you want to delete. The device must be previously added by ce_gw_add(). CE_GW_A_ID must be 0 if you want to delete a device.

Return values

0	on success
<0	on failure

Definition at line 333 of file ce_gw_netlink.c.

References CE_GW_A_DST, CE_GW_A_ID, ce_gw_dev_free(), ce_gw_dev_unregister(), and ce_gw_remove_route().

{
    int err = 0;
    if (info == NULL) {
        err = -ENODATA;
        pr_err("ce_gw: info attribute is missing."\
               " No Massage received: %d\n", err);
        return err;
    }

    struct nlattr *nla_id = info->attrs[CE_GW_A_ID];
    __u32 *nla_id_data = (__u32 *) nla_data(nla_id);

    /* DST Contains the device name to delete */
    struct nlattr *nla_dst = info->attrs[CE_GW_A_DST];
    char *nla_dst_data = (char *) nla_data(nla_dst);

    if (nla_dst == NULL) { /* del route is called in userspace */
        if (*nla_id_data == 0) {
            err = -ENODATA;
            pr_warning("ce_gw: ID is missing: %d\n", err);
            goto ce_gw_del_error;
        } else
            pr_debug("ce_gw: del device: %d\n", *nla_id_data);

        err = ce_gw_remove_route(*nla_id_data);

    } else { /* del dev is called in userspace */

        struct net_device *dev;
        dev = dev_get_by_name(&init_net, nla_dst_data);
        if (dev == NULL) {
            err = -ENODEV;
            pr_err("ce_gw_netlink: No such Device: %d\n", err);
            goto ce_gw_del_error;
        }
        dev_put(dev);

        ce_gw_dev_unregister(dev);
        ce_gw_dev_free(dev);
    }

ce_gw_del_error:
    netlink_ack(skb_info, info->nlhdr, -err);
    return err;
}

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int ce_gw_netlink_echo	(	struct sk_buff *	skb_info,
		struct genl_info *	info
	)

Generic Netlink Command - Sends a massage back.

Parameters

skb_info	Netlink Socket Buffer with Message
info	Additional Netlink Information

Return values

0	if parsing is finished

Definition at line 127 of file ce_gw_netlink.c.

References CE_GW_A_DATA, CE_GW_C_ECHO, ce_gw_genl_family, and CE_GW_NO_FLAG.

{
    struct sk_buff *skb;
    int err;
    void *user_hdr;

    if (info == NULL) {
        printk(KERN_ERR "ce_gw: info attribute is missing."\
               " No Massage received.\n");
        return -1;
    }

    struct nlattr *nla_a_msg = info->attrs[CE_GW_A_DATA];
    char *nla_a_msg_pay = (char *) nla_data(nla_a_msg);

    if (nla_a_msg_pay == NULL) {
        pr_warning("ce_gw: String Message is missing.\n");
    } else {
        pr_info("ce_gw: Messege received: %s\n", nla_a_msg_pay);
    }

    /* send a message back*/
    skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
    if (skb == NULL) {
        err = -ENOMEM;
        pr_err("ce_gw: Socket allocation failed.\n");
        goto ce_gw_add_error;
    }

#if LINUX_VERSION_CODE < KERNEL_VERSION(3,7,0)
    user_hdr = genlmsg_put(skb, info->snd_pid, info->snd_seq,
                           &ce_gw_genl_family, CE_GW_NO_FLAG, CE_GW_C_ECHO);
#else
    user_hdr = genlmsg_put(skb, info->snd_portid, info->snd_seq,
                           &ce_gw_genl_family, CE_GW_NO_FLAG, CE_GW_C_ECHO);
#endif

    if (user_hdr == NULL) {
        err = -ENOMEM;
        pr_err("ce_gw: Error during putting haeder\n");
        goto ce_gw_add_error;
    }

    err = nla_put_string(skb, CE_GW_A_DATA,
                         "hello world from kernel space   \n");
    if (err != 0) {
        pr_err("ce_gw: Putting Netlink Attribute Failed.\n");
        goto ce_gw_add_error;
    }

    genlmsg_end(skb, user_hdr);

#if LINUX_VERSION_CODE < KERNEL_VERSION(3,7,0)
    err = genlmsg_unicast(genl_info_net(info),skb,info->snd_pid);
#else
    err = genlmsg_unicast(genl_info_net(info),skb,info->snd_portid);
#endif
    if (err != 0) {
        pr_err("ce_gw: Message sending failed.\n");
        goto ce_gw_add_error;
    }

    return 0;

ce_gw_add_error:
    kfree_skb(skb);
    return err;
};

static void ce_gw_netlink_exit

(

void

)

Must called once at module exit.

During exit of module this function must called. It unregisters the family and its operations.

Definition at line 640 of file ce_gw_netlink.c.

References ce_gw_genl_family.

Referenced by ce_gw_cleanup().

                              {
    int err;
    err = genl_unregister_ops(&ce_gw_genl_family, &ce_gw_genl_ops_echo);
    if (err != 0) {
        pr_err("ce_gw: Error during unregistering operation echo: %i\n",
               err);
    }

    err = genl_unregister_ops(&ce_gw_genl_family, &ce_gw_genl_ops_add);
    if (err != 0) {
        pr_err("ce_gw: Error during unregistering operation add: %i\n",
               err);
    }

    err = genl_unregister_ops(&ce_gw_genl_family, &ce_gw_genl_ops_del);
    if (err != 0) {
        pr_err("ce_gw: Error during unregistering operation del: %i\n",
               err);
    }

    err = genl_unregister_ops(&ce_gw_genl_family, &ce_gw_genl_ops_list);
    if (err != 0) {
        pr_err("ce_gw: Error during unregistering operation del: %i\n",
               err);
    }

    err = genl_unregister_family(&ce_gw_genl_family);
    if (err != 0) {
        pr_err("ce_gw: Error during unregistering family ce_gw: %i\n",
               err);
    }
}

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int ce_gw_netlink_init

(

void

)

Must called once at module init.

During init of module this function must called. It registers the family and its operations.

Return values

0	when init successful
<0	if an error occurred.

Definition at line 581 of file ce_gw_netlink.c.

References ce_gw_genl_family.

Referenced by ce_gw_init_module().

                             {
    int err;

    if ((err = genl_register_family(&ce_gw_genl_family)) != 0) {
        pr_err("ce_gw: Error during registering family ce_gw: %i\n",
               err);
        goto ce_gw_init_family_err;
    }

    err = genl_register_ops(&ce_gw_genl_family, &ce_gw_genl_ops_echo);
    if (err != 0) {
        pr_err("ce_gw: Error during registering operation echo: %i\n",
               err);
        goto ce_gw_init_echo_err;
    }

    err = genl_register_ops(&ce_gw_genl_family, &ce_gw_genl_ops_del);
    if (err != 0) {
        pr_err("ce_gw: Error during registering operation del: %i\n",
               err);
        goto ce_gw_init_del_err;
    }

    err = genl_register_ops(&ce_gw_genl_family, &ce_gw_genl_ops_add);
    if (err != 0) {
        pr_err("ce_gw: Error during registering operation add: %i\n",
               err);
        goto ce_gw_init_add_err;
    }

    err = genl_register_ops(&ce_gw_genl_family, &ce_gw_genl_ops_list);
    if (err != 0) {
        pr_err("ce_gw: Error during registering operation list: %i\n",
               err);
        goto ce_gw_init_list_err;
    }

    return 0;


    err = genl_unregister_ops(&ce_gw_genl_family, &ce_gw_genl_ops_list);

ce_gw_init_list_err:
    err = genl_unregister_ops(&ce_gw_genl_family, &ce_gw_genl_ops_add);

ce_gw_init_add_err:
    err = genl_unregister_ops(&ce_gw_genl_family, &ce_gw_genl_ops_del);

ce_gw_init_del_err:
    err = genl_unregister_ops(&ce_gw_genl_family, &ce_gw_genl_ops_echo);

ce_gw_init_echo_err:
    err = genl_unregister_family(&ce_gw_genl_family);

ce_gw_init_family_err:
    return -1;
}

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int ce_gw_netlink_list	(	struct sk_buff *	skb_info,
		struct genl_info *	info
	)

Send informations of one or more routes to userspace.

Parameters

skb_info	Netlink Socket Buffer with Message
info	Additional Netlink Information

will be called by ce_gw_list() in userspace in cegwctl.

get Netlink Attribute:

• CE_GW_A_ID set it to 0 if you want to send all routes. Else set it to the route id you want to send.

Send multiple netlink Attributes back:

• CE_GW_A_SRC
• CE_GW_A_DST
• CE_GW_A_ID
• CE_GW_A_FLAGS
• CE_GW_A_TYPE
• CE_GW_A_HNDL
• CE_GW_A_DROP

Return values

0	on success
<0	on failure

Definition at line 401 of file ce_gw_netlink.c.

References CE_GW_A_DROP, CE_GW_A_DST, CE_GW_A_FLAGS, CE_GW_A_HNDL, CE_GW_A_ID, CE_GW_A_SRC, CE_GW_A_TYPE, CE_GW_C_ECHO, ce_gw_genl_family, ce_gw_get_job_list(), CE_GW_NO_FLAG, ce_gw_job::dev, ce_gw_job::dropped_frames, ce_gw_job::dst, ce_gw_job::flags, ce_gw_job::handled_frames, ce_gw_job::id, ce_gw_job::src, and ce_gw_job::type.

{
    struct sk_buff *skb;
    int err = 0;
    void *user_hdr;

    pr_debug("ce_gw_netlink: ce_gw_netlink_list is called.\n");

    struct nlattr *nla_id = info->attrs[CE_GW_A_ID];
    __u32 *nla_id_data = (__u32 *) nla_data(nla_id);

    /* TODO perhaps pare arguments like ID to only transmit a special GW */
    struct ce_gw_job *cgj;
    struct hlist_node *node;

#   if LINUX_VERSION_CODE >= KERNEL_VERSION(3,9,0)
    hlist_for_each_entry_safe(cgj, node, ce_gw_get_job_list(), list) {
#   else

    struct hlist_node *pos;
    hlist_for_each_entry_safe(cgj, pos, node, ce_gw_get_job_list(), list) {
#   endif
        if (*nla_id_data != 0 && cgj->id != *nla_id_data) {
            continue;
        }

        pr_debug("ce_gw_netlink: Job List entry is send.\n");

        skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
        if (skb == NULL) {
            pr_err("ce_gw: Socket allocation failed.\n");
            goto ce_gw_list_error;
        }

#       if LINUX_VERSION_CODE < KERNEL_VERSION(3,7,0)
        user_hdr = genlmsg_put(skb, info->snd_pid,
                               info->snd_seq, &ce_gw_genl_family,
                               NLM_F_MULTI, CE_GW_C_ECHO);

#       else
        user_hdr = genlmsg_put(skb, info->snd_portid,
                               info->snd_seq, &ce_gw_genl_family,
                               NLM_F_MULTI, CE_GW_C_ECHO);
#       endif
        if (user_hdr == NULL) {
            err = -ENOMEM;
            pr_err("ce_gw: Error during putting haeder\n");
            goto ce_gw_list_error;
        }

        err = nla_put_string(skb, CE_GW_A_SRC, cgj->src.dev->name);
        err += nla_put_string(skb, CE_GW_A_DST, cgj->dst.dev->name);
        err += nla_put_u32(skb, CE_GW_A_ID, cgj->id);
        err += nla_put_u32(skb, CE_GW_A_FLAGS, cgj->flags);
        err += nla_put_u8(skb, CE_GW_A_TYPE, cgj->type);
        err += nla_put_u32(skb, CE_GW_A_HNDL, cgj->handled_frames);
        err += nla_put_u32(skb, CE_GW_A_DROP, cgj->dropped_frames);
        if (err != 0) {
            pr_err("ce_gw: Putting Netlink Attribute Failed.\n");
            goto ce_gw_list_error;
        }

        genlmsg_end(skb, user_hdr);

#       if LINUX_VERSION_CODE < KERNEL_VERSION(3,7,0)
        err = genlmsg_unicast(genl_info_net(info), skb,
                              info->snd_pid);
#       else

        err = genlmsg_unicast(genl_info_net(info), skb,
                              info->snd_portid);
#       endif
        if (err != 0) {
            pr_err("ce_gw: Message sending failed.\n");
            goto ce_gw_list_error;
        }
    }

    /* send a DONE Message (of a Multimessage Series) back */
    struct nlmsghdr *nlhdr;
    skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);

    if (skb == NULL) {
        pr_err("ce_gw: Socket allocation failed.\n");
        goto ce_gw_list_error;
    }

#   if LINUX_VERSION_CODE < KERNEL_VERSION(3,7,0)
    nlhdr = nlmsg_put(skb, info->snd_pid, info->snd_seq,
                      NLMSG_DONE, 0, CE_GW_NO_FLAG);
#   else

    nlhdr = nlmsg_put(skb, info->snd_portid, info->snd_seq,
                      NLMSG_DONE, 0, CE_GW_NO_FLAG);
#   endif
    if (nlhdr == NULL) {
        err = -ENOMEM;
        pr_err("ce_gw: Error during putting haeder\n");
        goto ce_gw_list_error;
    }

    nlmsg_end(skb, nlhdr);

#   if LINUX_VERSION_CODE < KERNEL_VERSION(3,7,0)
    err = nlmsg_unicast(genl_info_net(info)->genl_sock, skb,
                        info->snd_pid);

#   else
    err = nlmsg_unicast(genl_info_net(info)->genl_sock, skb,
                        info->snd_portid);
#   endif
    if (err != 0) {
        pr_err("ce_gw: Message sending failed.\n");
        goto ce_gw_list_error;
    }

    return 0;

ce_gw_list_error:
    kfree_skb(skb);
    return err;
}

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Variable Documentation

struct genl_family ce_gw_genl_family

static

Initial value:

= {
    
    .id = GENL_ID_GENERATE,     
    .hdrsize = CE_GW_USER_HDR_SIZE, 
    .name = CE_GW_GE_FAMILY_NAME,   
    .version = CE_GW_GE_FAMILY_VERSION, 
    .maxattr = CE_GW_A_MAX,     
    .netnsok = false,
    .pre_doit = NULL,
    .post_doit = NULL,
    
}

Generic Netlink Family.

Definition at line 91 of file ce_gw_netlink.c.

Referenced by ce_gw_netlink_echo(), ce_gw_netlink_exit(), ce_gw_netlink_init(), and ce_gw_netlink_list().

struct genl_ops ce_gw_genl_ops_add

Initial value:

= {
    .cmd = CE_GW_C_ADD,
    .internal_flags = CE_GW_NO_FLAG,
    .flags = CE_GW_NO_FLAG,
    .policy = ce_gw_genl_policy,
    .doit = ce_gw_netlink_add,
    .dumpit = NULL,
    .done = NULL,
}

details of ce_gw_netlink_add()

Definition at line 542 of file ce_gw_netlink.c.

struct genl_ops ce_gw_genl_ops_del

Initial value:

= {
    .cmd = CE_GW_C_DEL,
    .internal_flags = CE_GW_NO_FLAG,
    .flags = CE_GW_NO_FLAG,
    .policy = ce_gw_genl_policy,
    .doit = ce_gw_netlink_del,
    .dumpit = NULL,
    .done = NULL,
}

details of ce_gw_netlink_del()

Definition at line 556 of file ce_gw_netlink.c.

struct genl_ops ce_gw_genl_ops_echo

Initial value:

= {
    .cmd = CE_GW_C_ECHO,
    .internal_flags = CE_GW_NO_FLAG,
    .flags = CE_GW_NO_FLAG,
    .policy = ce_gw_genl_policy,
    .doit = ce_gw_netlink_echo,
    .dumpit = NULL,
    .done = NULL,
}

details of ce_gw_netlink_echo()

Definition at line 528 of file ce_gw_netlink.c.

struct genl_ops ce_gw_genl_ops_list

Initial value:

= {
    .cmd = CE_GW_C_LIST,
    .internal_flags = CE_GW_NO_FLAG,
    .flags = CE_GW_NO_FLAG,
    .policy = ce_gw_genl_policy,
    .doit = ce_gw_netlink_list,
    .dumpit = NULL,
    .done = NULL,
}

details of ce_gw_netlink_list()

Definition at line 570 of file ce_gw_netlink.c.

struct nla_policy ce_gw_genl_policy[CE_GW_A_MAX+1]

static

Initial value:

= {
    [CE_GW_A_DATA] = { .type = NLA_NUL_STRING },
    [CE_GW_A_SRC] = { .type = NLA_NUL_STRING },
    [CE_GW_A_DST] = { .type = NLA_NUL_STRING },
    [CE_GW_A_ID] = { .type = NLA_U32 },
    [CE_GW_A_FLAGS] = { .type = NLA_U32 },
    [CE_GW_A_TYPE] = { .type = NLA_U8 },
    [CE_GW_A_HNDL] = { .type = NLA_U32 },
    [CE_GW_A_DROP] = { .type = NLA_U32 },
}

Netlink Policy - Defines the Type for the Netlink Attributes.

Definition at line 76 of file ce_gw_netlink.c.