genl: Support registration of families without depending on caches
Introduces the functions genl_register_family() and genl_unregister_family() to register a Generic Netlink family which does not implement a cachable type. API users can direct received messages into genl_handle_msg() which will validate the messages and call the callback functions defined in the commands definition. See test/test-genl.c for an example on how to use it.
This commit is contained in:
Thomas Graf
parent
3656b6f908
commit
faef2fa45f
4 changed files with 271 additions and 46 deletions
|
|
@ -110,16 +110,34 @@ struct genl_cmd
|
|||
*
|
||||
* Definition of a Generic Netlink family
|
||||
*
|
||||
* @par Example:
|
||||
* @code
|
||||
* static struct genl_cmd foo_cmds[] = {
|
||||
* [...]
|
||||
* };
|
||||
*
|
||||
* static struct genl_ops my_genl_ops = {
|
||||
* .o_name = "foo",
|
||||
* .o_hdrsize = sizeof(struct my_hdr),
|
||||
* .o_cmds = foo_cmds,
|
||||
* .o_ncmds = ARRAY_SIZE(foo_cmds),
|
||||
* };
|
||||
*
|
||||
* if ((err = genl_register_family(&my_genl_ops)) < 0)
|
||||
* // ERROR
|
||||
* @endcode
|
||||
*
|
||||
* @see genl_cmd
|
||||
*/
|
||||
struct genl_ops
|
||||
{
|
||||
int o_family;
|
||||
/** Length of user header */
|
||||
unsigned int o_hdrsize;
|
||||
|
||||
/** Numeric identifier, automatically resolved by genl_mngt_resolve() */
|
||||
/** Numeric identifier, automatically filled in by genl_ops_resolve() */
|
||||
int o_id;
|
||||
|
||||
/** Human readable name, used to resolve to numeric identifier */
|
||||
/** Human readable name, used by genl_ops_resolve() to resolve numeric id */
|
||||
char * o_name;
|
||||
|
||||
/**
|
||||
|
|
@ -128,12 +146,10 @@ struct genl_ops
|
|||
*/
|
||||
struct nl_cache_ops * o_cache_ops;
|
||||
|
||||
/**
|
||||
* Can point to an array of generic netlink commands definitions.
|
||||
*/
|
||||
/** Optional array defining the available Generic Netlink commands */
|
||||
struct genl_cmd * o_cmds;
|
||||
|
||||
/** Size of \c o_cmds array */
|
||||
/** Number of elements in \c o_cmds array */
|
||||
int o_ncmds;
|
||||
|
||||
/**
|
||||
|
|
@ -143,6 +159,9 @@ struct genl_ops
|
|||
struct nl_list_head o_list;
|
||||
};
|
||||
|
||||
extern int genl_register_family(struct genl_ops *);
|
||||
extern int genl_unregister_family(struct genl_ops *);
|
||||
extern int genl_handle_msg(struct nl_msg *, void *);
|
||||
|
||||
extern int genl_register(struct nl_cache_ops *);
|
||||
extern void genl_unregister(struct nl_cache_ops *);
|
||||
|
|
|
|||
193
lib/genl/mngt.c
193
lib/genl/mngt.c
|
|
@ -11,7 +11,7 @@
|
|||
|
||||
/**
|
||||
* @ingroup genl
|
||||
* @defgroup genl_mngt Family and Operations Management
|
||||
* @defgroup genl_mngt Family and Command Registration
|
||||
*
|
||||
* Registering Generic Netlink Families and Commands
|
||||
*
|
||||
|
|
@ -30,28 +30,34 @@
|
|||
|
||||
static NL_LIST_HEAD(genl_ops_list);
|
||||
|
||||
static int genl_msg_parser(struct nl_cache_ops *ops, struct sockaddr_nl *who,
|
||||
struct nlmsghdr *nlh, struct nl_parser_param *pp)
|
||||
static struct genl_cmd *lookup_cmd(struct genl_ops *ops, int cmd_id)
|
||||
{
|
||||
int i, err;
|
||||
struct genl_cmd *cmd;
|
||||
int i;
|
||||
|
||||
for (i = 0; i < ops->o_ncmds; i++) {
|
||||
cmd = &ops->o_cmds[i];
|
||||
if (cmd->c_id == cmd_id)
|
||||
return cmd;
|
||||
}
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static int cmd_msg_parser(struct sockaddr_nl *who, struct nlmsghdr *nlh,
|
||||
struct genl_ops *ops, struct nl_cache_ops *cache_ops, void *arg)
|
||||
{
|
||||
int err;
|
||||
struct genlmsghdr *ghdr;
|
||||
struct genl_cmd *cmd;
|
||||
|
||||
ghdr = nlmsg_data(nlh);
|
||||
ghdr = genlmsg_hdr(nlh);
|
||||
|
||||
if (ops->co_genl == NULL)
|
||||
BUG();
|
||||
|
||||
for (i = 0; i < ops->co_genl->o_ncmds; i++) {
|
||||
cmd = &ops->co_genl->o_cmds[i];
|
||||
if (cmd->c_id == ghdr->cmd)
|
||||
goto found;
|
||||
if (!(cmd = lookup_cmd(ops, ghdr->cmd))) {
|
||||
err = -NLE_MSGTYPE_NOSUPPORT;
|
||||
goto errout;
|
||||
}
|
||||
|
||||
err = -NLE_MSGTYPE_NOSUPPORT;
|
||||
goto errout;
|
||||
|
||||
found:
|
||||
if (cmd->c_msg_parser == NULL)
|
||||
err = -NLE_OPNOTSUPP;
|
||||
else {
|
||||
|
|
@ -64,33 +70,64 @@ found:
|
|||
.attrs = tb,
|
||||
};
|
||||
|
||||
err = nlmsg_parse(nlh, ops->co_hdrsize, tb, cmd->c_maxattr,
|
||||
err = nlmsg_parse(nlh, GENL_HDRSIZE(ops->o_hdrsize), tb, cmd->c_maxattr,
|
||||
cmd->c_attr_policy);
|
||||
if (err < 0)
|
||||
goto errout;
|
||||
|
||||
err = cmd->c_msg_parser(ops, cmd, &info, pp);
|
||||
err = cmd->c_msg_parser(cache_ops, cmd, &info, arg);
|
||||
}
|
||||
errout:
|
||||
return err;
|
||||
|
||||
}
|
||||
|
||||
static int genl_msg_parser(struct nl_cache_ops *ops, struct sockaddr_nl *who,
|
||||
struct nlmsghdr *nlh, struct nl_parser_param *pp)
|
||||
{
|
||||
if (ops->co_genl == NULL)
|
||||
BUG();
|
||||
|
||||
return cmd_msg_parser(who, nlh, ops->co_genl, ops, pp);
|
||||
}
|
||||
|
||||
static struct genl_ops *lookup_family(int family)
|
||||
{
|
||||
struct genl_ops *ops;
|
||||
|
||||
nl_list_for_each_entry(ops, &genl_ops_list, o_list) {
|
||||
if (ops->o_id == family)
|
||||
return ops;
|
||||
}
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static struct genl_ops *lookup_family_by_name(const char *name)
|
||||
{
|
||||
struct genl_ops *ops;
|
||||
|
||||
nl_list_for_each_entry(ops, &genl_ops_list, o_list) {
|
||||
if (!strcmp(ops->o_name, name))
|
||||
return ops;
|
||||
}
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
char *genl_op2name(int family, int op, char *buf, size_t len)
|
||||
{
|
||||
struct genl_ops *ops;
|
||||
int i;
|
||||
|
||||
nl_list_for_each_entry(ops, &genl_ops_list, o_list) {
|
||||
if (ops->o_family == family) {
|
||||
for (i = 0; i < ops->o_ncmds; i++) {
|
||||
struct genl_cmd *cmd;
|
||||
cmd = &ops->o_cmds[i];
|
||||
if ((ops = lookup_family(family))) {
|
||||
for (i = 0; i < ops->o_ncmds; i++) {
|
||||
struct genl_cmd *cmd;
|
||||
cmd = &ops->o_cmds[i];
|
||||
|
||||
if (cmd->c_id == op) {
|
||||
strncpy(buf, cmd->c_name, len - 1);
|
||||
return buf;
|
||||
}
|
||||
if (cmd->c_id == op) {
|
||||
strncpy(buf, cmd->c_name, len - 1);
|
||||
return buf;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
@ -102,7 +139,90 @@ char *genl_op2name(int family, int op, char *buf, size_t len)
|
|||
/** @endcond */
|
||||
|
||||
/**
|
||||
* @name Registration (Cache Based)
|
||||
* @name Registration
|
||||
* @{
|
||||
*/
|
||||
|
||||
/**
|
||||
* Register Generic Netlink family and associated commands
|
||||
* @arg ops Generic Netlink family definition
|
||||
*
|
||||
* Registers the specified Generic Netlink family definition together with
|
||||
* all associated commands. After registration, received Generic Netlink
|
||||
* messages can be passed to genl_handle_msg() which will validate the
|
||||
* messages, look for a matching command and call the respective callback
|
||||
* function automatically.
|
||||
*
|
||||
* @note Consider using genl_register() if the family is used to implement a
|
||||
* cacheable type.
|
||||
*
|
||||
* @see genl_unregister_family();
|
||||
* @see genl_register();
|
||||
*
|
||||
* @return 0 on success or a negative error code.
|
||||
*/
|
||||
int genl_register_family(struct genl_ops *ops)
|
||||
{
|
||||
if (!ops->o_name)
|
||||
return -NLE_INVAL;
|
||||
|
||||
if (ops->o_cmds && ops->o_ncmds <= 0)
|
||||
return -NLE_INVAL;
|
||||
|
||||
if (ops->o_id && lookup_family(ops->o_id))
|
||||
return -NLE_EXIST;
|
||||
|
||||
if (lookup_family_by_name(ops->o_name))
|
||||
return -NLE_EXIST;
|
||||
|
||||
nl_list_add_tail(&ops->o_list, &genl_ops_list);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* Unregister Generic Netlink family
|
||||
* @arg ops Generic Netlink family definition
|
||||
*
|
||||
* Unregisters a family and all associated commands that were previously
|
||||
* registered using genl_register_family().
|
||||
*
|
||||
* @see genl_register_family()
|
||||
*
|
||||
* @return 0 on success or a negative error code.
|
||||
*/
|
||||
int genl_unregister_family(struct genl_ops *ops)
|
||||
{
|
||||
nl_list_del(&ops->o_list);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* Run a received message through the demultiplexer
|
||||
* @arg msg Generic Netlink message
|
||||
* @arg arg Argument passed on to the message handler callback
|
||||
*
|
||||
* @return 0 on success or a negative error code.
|
||||
*/
|
||||
int genl_handle_msg(struct nl_msg *msg, void *arg)
|
||||
{
|
||||
struct nlmsghdr *nlh = nlmsg_hdr(msg);
|
||||
struct genl_ops *ops;
|
||||
|
||||
if (!genlmsg_valid_hdr(nlh, 0))
|
||||
return -NLE_INVAL;
|
||||
|
||||
if (!(ops = lookup_family(nlh->nlmsg_type)))
|
||||
return -NLE_MSGTYPE_NOSUPPORT;
|
||||
|
||||
return cmd_msg_parser(nlmsg_get_src(msg), nlh, ops, NULL, arg);
|
||||
}
|
||||
|
||||
/** @} */
|
||||
|
||||
/**
|
||||
* @name Registration of Cache Operations
|
||||
* @{
|
||||
*/
|
||||
|
||||
|
|
@ -110,6 +230,12 @@ char *genl_op2name(int family, int op, char *buf, size_t len)
|
|||
* Register Generic Netlink family backed cache
|
||||
* @arg ops Cache operations definition
|
||||
*
|
||||
* Same as genl_register_family() but additionally registers the specified
|
||||
* cache operations using nl_cache_mngt_register() and associates it with
|
||||
* the Generic Netlink family.
|
||||
*
|
||||
* @see genl_register_family()
|
||||
*
|
||||
* @return 0 on success or a negative error code.
|
||||
*/
|
||||
int genl_register(struct nl_cache_ops *ops)
|
||||
|
|
@ -132,13 +258,13 @@ int genl_register(struct nl_cache_ops *ops)
|
|||
}
|
||||
|
||||
ops->co_genl->o_cache_ops = ops;
|
||||
ops->co_genl->o_hdrsize = ops->co_hdrsize - GENL_HDRLEN;
|
||||
ops->co_genl->o_name = ops->co_msgtypes[0].mt_name;
|
||||
ops->co_genl->o_family = ops->co_msgtypes[0].mt_id;
|
||||
ops->co_genl->o_id = ops->co_msgtypes[0].mt_id;
|
||||
ops->co_msg_parser = genl_msg_parser;
|
||||
|
||||
/* FIXME: check for dup */
|
||||
|
||||
nl_list_add_tail(&ops->co_genl->o_list, &genl_ops_list);
|
||||
if ((err = genl_register_family(ops->co_genl)) < 0)
|
||||
goto errout;
|
||||
|
||||
err = nl_cache_mngt_register(ops);
|
||||
errout:
|
||||
|
|
@ -155,7 +281,8 @@ void genl_unregister(struct nl_cache_ops *ops)
|
|||
return;
|
||||
|
||||
nl_cache_mngt_unregister(ops);
|
||||
nl_list_del(&ops->co_genl->o_list);
|
||||
|
||||
genl_unregister_family(ops->co_genl);
|
||||
}
|
||||
|
||||
/** @} */
|
||||
|
|
|
|||
|
|
@ -81,9 +81,9 @@ static void print(struct nl_cache_ops *ops, void *arg)
|
|||
|
||||
printf(" genl:\n" \
|
||||
" name: %s\n" \
|
||||
" family: %d\n" \
|
||||
" user-hdr: %d\n" \
|
||||
" id: %d\n",
|
||||
genl_ops->o_name, genl_ops->o_family, genl_ops->o_id);
|
||||
genl_ops->o_name, genl_ops->o_hdrsize, genl_ops->o_id);
|
||||
|
||||
if (genl_ops->o_ncmds) {
|
||||
int i;
|
||||
|
|
|
|||
|
|
@ -1,4 +1,72 @@
|
|||
#include <netlink/cli/utils.h>
|
||||
#include <linux/taskstats.h>
|
||||
|
||||
static struct nla_policy attr_policy[TASKSTATS_TYPE_MAX+1] = {
|
||||
[TASKSTATS_TYPE_PID] = { .type = NLA_U32 },
|
||||
[TASKSTATS_TYPE_TGID] = { .type = NLA_U32 },
|
||||
[TASKSTATS_TYPE_STATS] = { .minlen = sizeof(struct taskstats) },
|
||||
[TASKSTATS_TYPE_AGGR_PID] = { .type = NLA_NESTED },
|
||||
[TASKSTATS_TYPE_AGGR_TGID] = { .type = NLA_NESTED },
|
||||
};
|
||||
|
||||
|
||||
static int parse_cmd_new(struct nl_cache_ops *unused, struct genl_cmd *cmd,
|
||||
struct genl_info *info, void *arg)
|
||||
{
|
||||
struct nlattr *attrs[TASKSTATS_TYPE_MAX+1];
|
||||
struct nlattr *nested;
|
||||
int err;
|
||||
|
||||
if (info->attrs[TASKSTATS_TYPE_AGGR_PID])
|
||||
nested = info->attrs[TASKSTATS_TYPE_AGGR_PID];
|
||||
else if (info->attrs[TASKSTATS_TYPE_AGGR_TGID])
|
||||
nested = info->attrs[TASKSTATS_TYPE_AGGR_TGID];
|
||||
else {
|
||||
fprintf(stderr, "Invalid taskstats message: Unable to find "
|
||||
"nested attribute/\n");
|
||||
return NL_SKIP;
|
||||
}
|
||||
|
||||
err = nla_parse_nested(attrs, TASKSTATS_TYPE_MAX, nested, attr_policy);
|
||||
if (err < 0) {
|
||||
nl_perror(err, "Error while parsing generic netlink message");
|
||||
return err;
|
||||
}
|
||||
|
||||
|
||||
if (attrs[TASKSTATS_TYPE_STATS]) {
|
||||
struct taskstats *stats = nla_data(attrs[TASKSTATS_TYPE_STATS]);
|
||||
|
||||
printf("%s pid %u uid %u gid %u parent %u\n",
|
||||
stats->ac_comm, stats->ac_pid, stats->ac_uid,
|
||||
stats->ac_gid, stats->ac_ppid);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int parse_cb(struct nl_msg *msg, void *arg)
|
||||
{
|
||||
return genl_handle_msg(msg, NULL);
|
||||
}
|
||||
|
||||
static struct genl_cmd cmds[] = {
|
||||
{
|
||||
.c_id = TASKSTATS_CMD_NEW,
|
||||
.c_name = "taskstats_new()",
|
||||
.c_maxattr = TASKSTATS_TYPE_MAX,
|
||||
.c_attr_policy = attr_policy,
|
||||
.c_msg_parser = &parse_cmd_new,
|
||||
},
|
||||
};
|
||||
|
||||
#define ARRAY_SIZE(X) (sizeof(X) / sizeof((X)[0]))
|
||||
|
||||
static struct genl_ops ops = {
|
||||
.o_name = TASKSTATS_GENL_NAME,
|
||||
.o_cmds = cmds,
|
||||
.o_ncmds = ARRAY_SIZE(cmds),
|
||||
};
|
||||
|
||||
int main(int argc, char *argv[])
|
||||
{
|
||||
|
|
@ -10,25 +78,36 @@ int main(int argc, char *argv[])
|
|||
sock = nl_cli_alloc_socket();
|
||||
nl_cli_connect(sock, NETLINK_GENERIC);
|
||||
|
||||
if ((err = genl_register_family(&ops)) < 0)
|
||||
nl_cli_fatal(err, "Unable to register Generic Netlink family");
|
||||
|
||||
if ((err = genl_ops_resolve(sock, &ops)) < 0)
|
||||
nl_cli_fatal(err, "Unable to resolve family name");
|
||||
|
||||
msg = nlmsg_alloc();
|
||||
if (msg == NULL)
|
||||
nl_cli_fatal(NLE_NOMEM, "Unable to allocate netlink message");
|
||||
|
||||
hdr = genlmsg_put(msg, NL_AUTO_PID, NL_AUTO_SEQ, GENL_ID_CTRL,
|
||||
0, 0, CTRL_CMD_GETFAMILY, 1);
|
||||
hdr = genlmsg_put(msg, NL_AUTO_PORT, NL_AUTO_SEQ, ops.o_id,
|
||||
0, 0, TASKSTATS_CMD_GET, TASKSTATS_GENL_VERSION);
|
||||
if (hdr == NULL)
|
||||
nl_cli_fatal(ENOMEM, "Unable to write genl header");
|
||||
|
||||
if ((err = nla_put_u32(msg, CTRL_ATTR_FAMILY_ID, GENL_ID_CTRL)) < 0)
|
||||
if ((err = nla_put_u32(msg, TASKSTATS_CMD_ATTR_PID, 1)) < 0)
|
||||
nl_cli_fatal(err, "Unable to add attribute: %s", nl_geterror(err));
|
||||
|
||||
if ((err = nl_send_auto_complete(sock, msg)) < 0)
|
||||
nl_cli_fatal(err, "Unable to send message: %s", nl_geterror(err));
|
||||
|
||||
nlmsg_free(msg);
|
||||
|
||||
if ((err = nl_socket_modify_cb(sock, NL_CB_VALID, NL_CB_CUSTOM,
|
||||
parse_cb, NULL)) < 0)
|
||||
nl_cli_fatal(err, "Unable to modify valid message callback");
|
||||
|
||||
if ((err = nl_recvmsgs_default(sock)) < 0)
|
||||
nl_cli_fatal(err, "Unable to receive message: %s", nl_geterror(err));
|
||||
|
||||
nlmsg_free(msg);
|
||||
nl_close(sock);
|
||||
nl_socket_free(sock);
|
||||
|
||||
|
|
|
|||
Loading…
Add table
Reference in a new issue