[PATCH] Generic Netlink multicast groups support
Dmytro Kukulniak
dima.ky at gmail.com
Wed Jun 30 13:02:25 EDT 2010
Hello,
I have a patch against commit d378220c96c3c8b6f27dca33e7d8ba03318f9c2d
extending libnl with a facility to receive generic netlink messages sent
to multicast groups.
Essentially it add one new function genl_ctrl_resolve_grp which
prototype looks like this
int genl_ctrl_resolve_grp(struct nl_sock *sk, const char *family_name,
const char *grp_name)
It resolves the family name and the group name to group id. Then
the returned id can be used in nl_socket_add_membership to subscribe
to multicast messages.
Besides that it adds two more functions
uint32_t nl_socket_get_peer_groups(struct nl_sock *sk)
void nl_socket_set_peer_groups(struct nl_sock *sk, uint32_t groups)
allowing to modify the socket peer groups field. So it's possible to
multicast messages from the user space using the legacy interface.
Looks like there is no way (or I was not able to find one?) to modify
the netlink socket destination group from the user space, when the
group id is greater then 32.
--
regards, Dima
diff --git a/include/linux/genetlink.h b/include/linux/genetlink.h
index f7a9377..b834ef6 100644
--- a/include/linux/genetlink.h
+++ b/include/linux/genetlink.h
@@ -1,6 +1,7 @@
#ifndef __LINUX_GENERIC_NETLINK_H
#define __LINUX_GENERIC_NETLINK_H
+#include <linux/types.h>
#include <linux/netlink.h>
#define GENL_NAMSIZ 16 /* length of family name */
@@ -39,6 +40,9 @@ enum {
CTRL_CMD_NEWOPS,
CTRL_CMD_DELOPS,
CTRL_CMD_GETOPS,
+ CTRL_CMD_NEWMCAST_GRP,
+ CTRL_CMD_DELMCAST_GRP,
+ CTRL_CMD_GETMCAST_GRP, /* unused */
__CTRL_CMD_MAX,
};
@@ -52,6 +56,7 @@ enum {
CTRL_ATTR_HDRSIZE,
CTRL_ATTR_MAXATTR,
CTRL_ATTR_OPS,
+ CTRL_ATTR_MCAST_GROUPS,
__CTRL_ATTR_MAX,
};
@@ -66,4 +71,13 @@ enum {
#define CTRL_ATTR_OP_MAX (__CTRL_ATTR_OP_MAX - 1)
+enum {
+ CTRL_ATTR_MCAST_GRP_UNSPEC,
+ CTRL_ATTR_MCAST_GRP_NAME,
+ CTRL_ATTR_MCAST_GRP_ID,
+ __CTRL_ATTR_MCAST_GRP_MAX,
+};
+
+#define CTRL_ATTR_MCAST_GRP_MAX (__CTRL_ATTR_MCAST_GRP_MAX - 1)
+
#endif /* __LINUX_GENERIC_NETLINK_H */
diff --git a/include/netlink-types.h b/include/netlink-types.h
index ace5dde..c30aa17 100644
--- a/include/netlink-types.h
+++ b/include/netlink-types.h
@@ -701,6 +701,13 @@ struct genl_family_op
struct nl_list_head o_list;
};
+struct genl_family_grp {
+ struct genl_family *family; /* private */
+ struct nl_list_head list; /* private */
+ char name[GENL_NAMSIZ];
+ u_int32_t id;
+};
+
struct genl_family
{
NLHDR_COMMON
@@ -712,6 +719,7 @@ struct genl_family
uint32_t gf_maxattr;
struct nl_list_head gf_ops;
+ struct nl_list_head gf_mc_grps;
};
union nfnl_ct_proto
diff --git a/include/netlink/genl/ctrl.h b/include/netlink/genl/ctrl.h
index 1ae62f4..26a0a99 100644
--- a/include/netlink/genl/ctrl.h
+++ b/include/netlink/genl/ctrl.h
@@ -29,6 +29,9 @@ extern struct genl_family *
genl_ctrl_search_by_name(struct nl_cache *,
const char *);
extern int genl_ctrl_resolve(struct nl_sock *,
const char *);
+extern int genl_ctrl_resolve_grp(struct
nl_sock *sk,
+ const char
*family,
+ const char *grp);
#ifdef __cplusplus
}
diff --git a/include/netlink/genl/family.h
b/include/netlink/genl/family.h
index 74319e5..721dc13 100644
--- a/include/netlink/genl/family.h
+++ b/include/netlink/genl/family.h
@@ -42,6 +42,9 @@ extern void
genl_family_set_maxattr(struct genl_family *,
extern int genl_family_add_op(struct
genl_family *,
int, int);
+extern int genl_family_add_grp(struct
genl_family *,
+ uint32_t , const char *);
+
#ifdef __cplusplus
}
diff --git a/include/netlink/genl/genl.h b/include/netlink/genl/genl.h
index 3f3340c..364a471 100644
--- a/include/netlink/genl/genl.h
+++ b/include/netlink/genl/genl.h
@@ -21,7 +21,6 @@ extern "C" {
#endif
extern int genl_connect(struct nl_sock *);
-
extern int genl_send_simple(struct nl_sock *, int, int,
int, int);
diff --git a/include/netlink/socket.h b/include/netlink/socket.h
index 7e71aed..31a36d3 100644
--- a/include/netlink/socket.h
+++ b/include/netlink/socket.h
@@ -37,7 +37,8 @@ extern void nl_join_groups(struct
nl_sock *, int);
extern uint32_t nl_socket_get_peer_port(struct nl_sock
*);
extern void nl_socket_set_peer_port(struct nl_sock *,
uint32_t);
-
+extern uint32_t nl_socket_get_peer_groups(struct nl_sock *sk);
+extern void nl_socket_set_peer_groups(struct nl_sock
*sk, uint32_t groups);
extern struct nl_cb * nl_socket_get_cb(struct nl_sock *);
extern void nl_socket_set_cb(struct nl_sock *,
struct nl_cb *);
diff --git a/lib/genl/ctrl.c b/lib/genl/ctrl.c
index 1301642..3871795 100644
--- a/lib/genl/ctrl.c
+++ b/lib/genl/ctrl.c
@@ -45,6 +45,7 @@ static struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1]
= {
[CTRL_ATTR_HDRSIZE] = { .type = NLA_U32 },
[CTRL_ATTR_MAXATTR] = { .type = NLA_U32 },
[CTRL_ATTR_OPS] = { .type = NLA_NESTED },
+ [CTRL_ATTR_MCAST_GROUPS] = { .type = NLA_NESTED },
};
static struct nla_policy family_op_policy[CTRL_ATTR_OP_MAX+1] = {
@@ -52,6 +53,11 @@ static struct nla_policy
family_op_policy[CTRL_ATTR_OP_MAX+1] = {
[CTRL_ATTR_OP_FLAGS] = { .type = NLA_U32 },
};
+static struct nla_policy family_grp_policy[CTRL_ATTR_MCAST_GRP_MAX+1]
= {
+ [CTRL_ATTR_MCAST_GRP_NAME] = { .type = NLA_STRING },
+ [CTRL_ATTR_MCAST_GRP_ID] = { .type = NLA_U32 },
+};
+
static int ctrl_msg_parser(struct nl_cache_ops *ops, struct genl_cmd
*cmd,
struct genl_info *info, void *arg)
{
@@ -126,6 +132,40 @@ static int ctrl_msg_parser(struct nl_cache_ops
*ops, struct genl_cmd *cmd,
}
}
+
+ if (info->attrs[CTRL_ATTR_MCAST_GROUPS]) {
+ struct nlattr *nla, *nla_grps;
+ int remaining;
+
+ nla_grps = info->attrs[CTRL_ATTR_MCAST_GROUPS];
+ nla_for_each_nested(nla, nla_grps, remaining) {
+ struct nlattr *tb[CTRL_ATTR_MCAST_GRP_MAX+1];
+ int id;
+ const char * name;
+
+ err = nla_parse_nested(tb,
CTRL_ATTR_MCAST_GRP_MAX, nla,
+ family_grp_policy);
+ if (err < 0)
+ goto errout;
+
+ if (tb[CTRL_ATTR_MCAST_GRP_ID] == NULL) {
+ err = -NLE_MISSING_ATTR;
+ goto errout;
+ }
+ id = nla_get_u32(tb[CTRL_ATTR_MCAST_GRP_ID]);
+
+ if (tb[CTRL_ATTR_MCAST_GRP_NAME] == NULL) {
+ err = -NLE_MISSING_ATTR;
+ goto errout;
+ }
+ name =
nla_get_string(tb[CTRL_ATTR_MCAST_GRP_NAME]);
+
+ err = genl_family_add_grp(family, id, name);
+ if (err < 0)
+ goto errout;
+ }
+
+ }
err = pp->pp_cb((struct nl_object *) family, pp);
errout:
@@ -242,6 +282,44 @@ errout:
return err;
}
+static int genl_ctrl_grp_by_name(const struct genl_family *family,
+ const char *grp_name)
+{
+ struct genl_family_grp *grp;
+
+ nl_list_for_each_entry(grp, &family->gf_mc_grps, list) {
+ if (!strcmp(grp->name, grp_name)) {
+ return grp->id;
+ }
+ }
+
+ return 0;
+}
+
+int genl_ctrl_resolve_grp(struct nl_sock *sk, const char *family_name,
+ const char *grp_name)
+{
+ struct nl_cache *cache;
+ struct genl_family *family;
+ int err;
+
+ if ((err = genl_ctrl_alloc_cache(sk, &cache)) < 0)
+ return err;
+
+ family = genl_ctrl_search_by_name(cache, family_name);
+ if (family == NULL) {
+ err = -NLE_OBJ_NOTFOUND;
+ goto errout;
+ }
+
+ err = genl_ctrl_grp_by_name(family, grp_name);
+ genl_family_put(family);
+errout:
+ nl_cache_free(cache);
+
+ return err;
+}
+
/** @} */
static struct genl_cmd genl_cmds[] = {
diff --git a/lib/genl/family.c b/lib/genl/family.c
index 4c6c18d..687f4b1 100644
--- a/lib/genl/family.c
+++ b/lib/genl/family.c
@@ -39,12 +39,14 @@ static void family_constructor(struct nl_object *c)
struct genl_family *family = (struct genl_family *) c;
nl_init_list_head(&family->gf_ops);
+ nl_init_list_head(&family->gf_mc_grps);
}
static void family_free_data(struct nl_object *c)
{
struct genl_family *family = (struct genl_family *) c;
struct genl_family_op *ops, *tmp;
+ struct genl_family_grp *grp, *t_grp;
if (family == NULL)
return;
@@ -53,6 +55,12 @@ static void family_free_data(struct nl_object *c)
nl_list_del(&ops->o_list);
free(ops);
}
+
+ nl_list_for_each_entry_safe(grp, t_grp, &family->gf_mc_grps,
list) {
+ nl_list_del(&grp->list);
+ free(grp);
+ }
+
}
static int family_clone(struct nl_object *_dst, struct nl_object *_src)
@@ -60,6 +68,7 @@ static int family_clone(struct nl_object *_dst,
struct nl_object *_src)
struct genl_family *dst = nl_object_priv(_dst);
struct genl_family *src = nl_object_priv(_src);
struct genl_family_op *ops;
+ struct genl_family_grp *grp;
int err;
nl_list_for_each_entry(ops, &src->gf_ops, o_list) {
@@ -67,6 +76,13 @@ static int family_clone(struct nl_object *_dst,
struct nl_object *_src)
if (err < 0)
return err;
}
+
+ nl_list_for_each_entry(grp, &src->gf_mc_grps, list) {
+ err = genl_family_add_grp(dst, grp->id, grp->name);
+ if (err < 0)
+ return err;
+ }
+
return 0;
}
@@ -93,6 +109,7 @@ static char *ops_flags2str(int flags, char *buf,
size_t len)
static void family_dump_details(struct nl_object *obj, struct
nl_dump_params *p)
{
+ struct genl_family_grp *grp;
struct genl_family *family = (struct genl_family *) obj;
family_dump_line(obj, p);
@@ -118,6 +135,11 @@ static void family_dump_details(struct nl_object
*obj, struct nl_dump_params *p)
nl_dump(p, "\n");
}
}
+
+ nl_list_for_each_entry(grp, &family->gf_mc_grps, list) {
+ nl_dump_line(p, " grp %s (0x%02x)\n", grp->name,
grp->id);
+ }
+
}
static void family_dump_stats(struct nl_object *obj, struct
nl_dump_params *p)
@@ -255,6 +277,23 @@ int genl_family_add_op(struct genl_family *family,
int id, int flags)
return 0;
}
+int genl_family_add_grp(struct genl_family *family, uint32_t id,
+ const char *name)
+{
+ struct genl_family_grp *grp;
+
+ grp = calloc(1, sizeof(*grp));
+ if (grp == NULL)
+ return -NLE_NOMEM;
+
+ grp->id = id;
+ strncpy(grp->name, name, GENL_NAMSIZ - 1);
+
+ nl_list_add_tail(&grp->list, &family->gf_mc_grps);
+
+ return 0;
+}
+
/** @} */
/** @cond SKIP */
diff --git a/lib/socket.c b/lib/socket.c
index 8083bbb..bed53c1 100644
--- a/lib/socket.c
+++ b/lib/socket.c
@@ -398,6 +398,18 @@ void nl_socket_set_peer_port(struct nl_sock *sk,
uint32_t port)
sk->s_peer.nl_pid = port;
}
+uint32_t nl_socket_get_peer_groups(struct nl_sock *sk)
+{
+ return sk->s_peer.nl_groups;
+}
+
+void nl_socket_set_peer_groups(struct nl_sock *sk, uint32_t groups)
+{
+ sk->s_peer.nl_groups = groups;
+}
+
+
+
/** @} */
/**
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