diff options
Diffstat (limited to 'include/linux/genl_magic_func.h')
| -rw-r--r-- | include/linux/genl_magic_func.h | 417 |
1 files changed, 417 insertions, 0 deletions
diff --git a/include/linux/genl_magic_func.h b/include/linux/genl_magic_func.h new file mode 100644 index 000000000000..8a86f659d363 --- /dev/null +++ b/include/linux/genl_magic_func.h @@ -0,0 +1,417 @@ +#ifndef GENL_MAGIC_FUNC_H +#define GENL_MAGIC_FUNC_H + +#include <linux/genl_magic_struct.h> + +/* + * Extension of genl attribute validation policies {{{1 + * {{{2 + */ + +/** + * nla_is_required - return true if this attribute is required + * @nla: netlink attribute + */ +static inline int nla_is_required(const struct nlattr *nla) +{ + return nla->nla_type & GENLA_F_REQUIRED; +} + +/** + * nla_is_mandatory - return true if understanding this attribute is mandatory + * @nla: netlink attribute + * Note: REQUIRED attributes are implicitly MANDATORY as well + */ +static inline int nla_is_mandatory(const struct nlattr *nla) +{ + return nla->nla_type & (GENLA_F_MANDATORY | GENLA_F_REQUIRED); +} + +/* Functionality to be integrated into nla_parse(), and validate_nla(), + * respectively. + * + * Enforcing the "mandatory" bit is done here, + * by rejecting unknown mandatory attributes. + * + * Part of enforcing the "required" flag would mean to embed it into + * nla_policy.type, and extending validate_nla(), which currently does + * BUG_ON(pt->type > NLA_TYPE_MAX); we have to work on existing kernels, + * so we cannot do that. Thats why enforcing "required" is done in the + * generated assignment functions below. */ +static int nla_check_unknown(int maxtype, struct nlattr *head, int len) +{ + struct nlattr *nla; + int rem; + nla_for_each_attr(nla, head, len, rem) { + __u16 type = nla_type(nla); + if (type > maxtype && nla_is_mandatory(nla)) + return -EOPNOTSUPP; + } + return 0; +} + +/* + * Magic: declare tla policy {{{1 + * Magic: declare nested policies + * {{{2 + */ +#undef GENL_mc_group +#define GENL_mc_group(group) + +#undef GENL_notification +#define GENL_notification(op_name, op_num, mcast_group, tla_list) + +#undef GENL_op +#define GENL_op(op_name, op_num, handler, tla_list) + +#undef GENL_struct +#define GENL_struct(tag_name, tag_number, s_name, s_fields) \ + [tag_name] = { .type = NLA_NESTED }, + +static struct nla_policy CONCAT_(GENL_MAGIC_FAMILY, _tla_nl_policy)[] = { +#include GENL_MAGIC_INCLUDE_FILE +}; + +#undef GENL_struct +#define GENL_struct(tag_name, tag_number, s_name, s_fields) \ +static struct nla_policy s_name ## _nl_policy[] __read_mostly = \ +{ s_fields }; + +#undef __field +#define __field(attr_nr, attr_flag, name, nla_type, _type, __get, __put) \ + [__nla_type(attr_nr)] = { .type = nla_type }, + +#undef __array +#define __array(attr_nr, attr_flag, name, nla_type, _type, maxlen, \ + __get, __put) \ + [__nla_type(attr_nr)] = { .type = nla_type, \ + .len = maxlen - (nla_type == NLA_NUL_STRING) }, + +#include GENL_MAGIC_INCLUDE_FILE + +#ifndef __KERNEL__ +#ifndef pr_info +#define pr_info(args...) fprintf(stderr, args); +#endif +#endif + +#if 1 +static void dprint_field(const char *dir, int nla_type, + const char *name, void *valp) +{ + __u64 val = valp ? *(__u32 *)valp : 1; + switch (nla_type) { + case NLA_U8: val = (__u8)val; + case NLA_U16: val = (__u16)val; + case NLA_U32: val = (__u32)val; + pr_info("%s attr %s: %d 0x%08x\n", dir, + name, (int)val, (unsigned)val); + break; + case NLA_U64: + val = *(__u64*)valp; + pr_info("%s attr %s: %lld 0x%08llx\n", dir, + name, (long long)val, (unsigned long long)val); + break; + case NLA_FLAG: + if (val) + pr_info("%s attr %s: set\n", dir, name); + break; + } +} + +static void dprint_array(const char *dir, int nla_type, + const char *name, const char *val, unsigned len) +{ + switch (nla_type) { + case NLA_NUL_STRING: + if (len && val[len-1] == '\0') + len--; + pr_info("%s attr %s: [len:%u] '%s'\n", dir, name, len, val); + break; + default: + /* we can always show 4 byte, + * thats what nlattr are aligned to. */ + pr_info("%s attr %s: [len:%u] %02x%02x%02x%02x ...\n", + dir, name, len, val[0], val[1], val[2], val[3]); + } +} + +#define DPRINT_TLA(a, op, b) pr_info("%s %s %s\n", a, op, b); + +/* Name is a member field name of the struct s. + * If s is NULL (only parsing, no copy requested in *_from_attrs()), + * nla is supposed to point to the attribute containing the information + * corresponding to that struct member. */ +#define DPRINT_FIELD(dir, nla_type, name, s, nla) \ + do { \ + if (s) \ + dprint_field(dir, nla_type, #name, &s->name); \ + else if (nla) \ + dprint_field(dir, nla_type, #name, \ + (nla_type == NLA_FLAG) ? NULL \ + : nla_data(nla)); \ + } while (0) + +#define DPRINT_ARRAY(dir, nla_type, name, s, nla) \ + do { \ + if (s) \ + dprint_array(dir, nla_type, #name, \ + s->name, s->name ## _len); \ + else if (nla) \ + dprint_array(dir, nla_type, #name, \ + nla_data(nla), nla_len(nla)); \ + } while (0) +#else +#define DPRINT_TLA(a, op, b) do {} while (0) +#define DPRINT_FIELD(dir, nla_type, name, s, nla) do {} while (0) +#define DPRINT_ARRAY(dir, nla_type, name, s, nla) do {} while (0) +#endif + +/* + * Magic: provide conversion functions {{{1 + * populate struct from attribute table: + * {{{2 + */ + +/* processing of generic netlink messages is serialized. + * use one static buffer for parsing of nested attributes */ +static struct nlattr *nested_attr_tb[128]; + +#ifndef BUILD_BUG_ON +/* Force a compilation error if condition is true */ +#define BUILD_BUG_ON(condition) ((void)BUILD_BUG_ON_ZERO(condition)) +/* Force a compilation error if condition is true, but also produce a + result (of value 0 and type size_t), so the expression can be used + e.g. in a structure initializer (or where-ever else comma expressions + aren't permitted). */ +#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); })) +#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); })) +#endif + +#undef GENL_struct +#define GENL_struct(tag_name, tag_number, s_name, s_fields) \ + /* static, potentially unused */ \ +int s_name ## _from_attrs(struct s_name *s, struct nlattr *tb[]) \ +{ \ + const int maxtype = ARRAY_SIZE(s_name ## _nl_policy)-1; \ + struct nlattr *tla = tb[tag_number]; \ + struct nlattr **ntb = nested_attr_tb; \ + struct nlattr *nla; \ + int err; \ + BUILD_BUG_ON(ARRAY_SIZE(s_name ## _nl_policy) > ARRAY_SIZE(nested_attr_tb)); \ + if (!tla) \ + return -ENOMSG; \ + DPRINT_TLA(#s_name, "<=-", #tag_name); \ + err = nla_parse_nested(ntb, maxtype, tla, s_name ## _nl_policy); \ + if (err) \ + return err; \ + err = nla_check_unknown(maxtype, nla_data(tla), nla_len(tla)); \ + if (err) \ + return err; \ + \ + s_fields \ + return 0; \ +} + +#undef __field +#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put) \ + nla = ntb[__nla_type(attr_nr)]; \ + if (nla) { \ + if (s) \ + s->name = __get(nla); \ + DPRINT_FIELD("<<", nla_type, name, s, nla); \ + } else if ((attr_flag) & GENLA_F_REQUIRED) { \ + pr_info("<< missing attr: %s\n", #name); \ + return -ENOMSG; \ + } + +/* validate_nla() already checked nla_len <= maxlen appropriately. */ +#undef __array +#define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, __get, __put) \ + nla = ntb[__nla_type(attr_nr)]; \ + if (nla) { \ + if (s) \ + s->name ## _len = \ + __get(s->name, nla, maxlen); \ + DPRINT_ARRAY("<<", nla_type, name, s, nla); \ + } else if ((attr_flag) & GENLA_F_REQUIRED) { \ + pr_info("<< missing attr: %s\n", #name); \ + return -ENOMSG; \ + } \ + +#include GENL_MAGIC_INCLUDE_FILE + +#undef GENL_struct +#define GENL_struct(tag_name, tag_number, s_name, s_fields) + +/* + * Magic: define op number to op name mapping {{{1 + * {{{2 + */ +const char *CONCAT_(GENL_MAGIC_FAMILY, _genl_cmd_to_str)(__u8 cmd) +{ + switch (cmd) { +#undef GENL_op +#define GENL_op(op_name, op_num, handler, tla_list) \ + case op_num: return #op_name; +#include GENL_MAGIC_INCLUDE_FILE + default: + return "unknown"; + } +} + +#ifdef __KERNEL__ +#include <linux/stringify.h> +/* + * Magic: define genl_ops {{{1 + * {{{2 + */ + +#undef GENL_op +#define GENL_op(op_name, op_num, handler, tla_list) \ +{ \ + handler \ + .cmd = op_name, \ + .policy = CONCAT_(GENL_MAGIC_FAMILY, _tla_nl_policy), \ +}, + +#define ZZZ_genl_ops CONCAT_(GENL_MAGIC_FAMILY, _genl_ops) +static struct genl_ops ZZZ_genl_ops[] __read_mostly = { +#include GENL_MAGIC_INCLUDE_FILE +}; + +#undef GENL_op +#define GENL_op(op_name, op_num, handler, tla_list) + +/* + * Define the genl_family, multicast groups, {{{1 + * and provide register/unregister functions. + * {{{2 + */ +#define ZZZ_genl_family CONCAT_(GENL_MAGIC_FAMILY, _genl_family) +static struct genl_family ZZZ_genl_family __read_mostly = { + .id = GENL_ID_GENERATE, + .name = __stringify(GENL_MAGIC_FAMILY), + .version = GENL_MAGIC_VERSION, +#ifdef GENL_MAGIC_FAMILY_HDRSZ + .hdrsize = NLA_ALIGN(GENL_MAGIC_FAMILY_HDRSZ), +#endif + .maxattr = ARRAY_SIZE(drbd_tla_nl_policy)-1, +}; + +/* + * Magic: define multicast groups + * Magic: define multicast group registration helper + */ +#undef GENL_mc_group +#define GENL_mc_group(group) \ +static struct genl_multicast_group \ +CONCAT_(GENL_MAGIC_FAMILY, _mcg_ ## group) __read_mostly = { \ + .name = #group, \ +}; \ +static int CONCAT_(GENL_MAGIC_FAMILY, _genl_multicast_ ## group)( \ + struct sk_buff *skb, gfp_t flags) \ +{ \ + unsigned int group_id = \ + CONCAT_(GENL_MAGIC_FAMILY, _mcg_ ## group).id; \ + if (!group_id) \ + return -EINVAL; \ + return genlmsg_multicast(skb, 0, group_id, flags); \ +} + +#include GENL_MAGIC_INCLUDE_FILE + +int CONCAT_(GENL_MAGIC_FAMILY, _genl_register)(void) +{ + int err = genl_register_family_with_ops(&ZZZ_genl_family, + ZZZ_genl_ops, ARRAY_SIZE(ZZZ_genl_ops)); + if (err) + return err; +#undef GENL_mc_group +#define GENL_mc_group(group) \ + err = genl_register_mc_group(&ZZZ_genl_family, \ + &CONCAT_(GENL_MAGIC_FAMILY, _mcg_ ## group)); \ + if (err) \ + goto fail; \ + else \ + pr_info("%s: mcg %s: %u\n", #group, \ + __stringify(GENL_MAGIC_FAMILY), \ + CONCAT_(GENL_MAGIC_FAMILY, _mcg_ ## group).id); + +#include GENL_MAGIC_INCLUDE_FILE + +#undef GENL_mc_group +#define GENL_mc_group(group) + return 0; +fail: + genl_unregister_family(&ZZZ_genl_family); + return err; +} + +void CONCAT_(GENL_MAGIC_FAMILY, _genl_unregister)(void) +{ + genl_unregister_family(&ZZZ_genl_family); +} + +/* + * Magic: provide conversion functions {{{1 + * populate skb from struct. + * {{{2 + */ + +#undef GENL_op +#define GENL_op(op_name, op_num, handler, tla_list) + +#undef GENL_struct +#define GENL_struct(tag_name, tag_number, s_name, s_fields) \ +static int s_name ## _to_skb(struct sk_buff *skb, struct s_name *s, \ + const bool exclude_sensitive) \ +{ \ + struct nlattr *tla = nla_nest_start(skb, tag_number); \ + if (!tla) \ + goto nla_put_failure; \ + DPRINT_TLA(#s_name, "-=>", #tag_name); \ + s_fields \ + nla_nest_end(skb, tla); \ + return 0; \ + \ +nla_put_failure: \ + if (tla) \ + nla_nest_cancel(skb, tla); \ + return -EMSGSIZE; \ +} \ +static inline int s_name ## _to_priv_skb(struct sk_buff *skb, \ + struct s_name *s) \ +{ \ + return s_name ## _to_skb(skb, s, 0); \ +} \ +static inline int s_name ## _to_unpriv_skb(struct sk_buff *skb, \ + struct s_name *s) \ +{ \ + return s_name ## _to_skb(skb, s, 1); \ +} + + +#undef __field +#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put) \ + if (!exclude_sensitive || !((attr_flag) & GENLA_F_SENSITIVE)) { \ + DPRINT_FIELD(">>", nla_type, name, s, NULL); \ + __put(skb, attr_nr, s->name); \ + } + +#undef __array +#define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, __get, __put) \ + if (!exclude_sensitive || !((attr_flag) & GENLA_F_SENSITIVE)) { \ + DPRINT_ARRAY(">>",nla_type, name, s, NULL); \ + __put(skb, attr_nr, min_t(int, maxlen, \ + s->name ## _len + (nla_type == NLA_NUL_STRING)),\ + s->name); \ + } + +#include GENL_MAGIC_INCLUDE_FILE + +#endif /* __KERNEL__ */ + +/* }}}1 */ +#endif /* GENL_MAGIC_FUNC_H */ +/* vim: set foldmethod=marker foldlevel=1 nofoldenable : */ |