name : genl_magic_func.h /* SPDX-License-Identifier: GPL-2.0 */ #ifndef GENL_MAGIC_FUNC_H #define GENL_MAGIC_FUNC_H #include <linux/args.h> #include <linux/build_bug.h> #include <linux/genl_magic_struct.h> /* * 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 CONCATENATE(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, __is_signed) \ [attr_nr] = { .type = nla_type }, #undef __array #define __array(attr_nr, attr_flag, name, nla_type, _type, maxlen, \ __get, __put, __is_signed) \ [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 #ifdef GENL_MAGIC_DEBUG 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]; #undef GENL_struct #define GENL_struct(tag_name, tag_number, s_name, s_fields) \ /* *_from_attrs functions are static, but potentially unused */ \ static int __ ## s_name ## _from_attrs(struct s_name *s, \ struct genl_info *info, bool exclude_invariants) \ { \ const int maxtype = ARRAY_SIZE(s_name ## _nl_policy)-1; \ struct nlattr *tla = info->attrs[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 = drbd_nla_parse_nested(ntb, maxtype, tla, s_name ## _nl_policy); \ if (err) \ return err; \ \ s_fields \ return 0; \ } __attribute__((unused)) \ static int s_name ## _from_attrs(struct s_name *s, \ struct genl_info *info) \ { \ return __ ## s_name ## _from_attrs(s, info, false); \ } __attribute__((unused)) \ static int s_name ## _from_attrs_for_change(struct s_name *s, \ struct genl_info *info) \ { \ return __ ## s_name ## _from_attrs(s, info, true); \ } __attribute__((unused)) \ #define __assign(attr_nr, attr_flag, name, nla_type, type, assignment...) \ nla = ntb[attr_nr]; \ if (nla) { \ if (exclude_invariants && !!((attr_flag) & DRBD_F_INVARIANT)) { \ pr_info("<< must not change invariant attr: %s\n", #name); \ return -EEXIST; \ } \ assignment; \ } else if (exclude_invariants && !!((attr_flag) & DRBD_F_INVARIANT)) { \ /* attribute missing from payload, */ \ /* which was expected */ \ } else if ((attr_flag) & DRBD_F_REQUIRED) { \ pr_info("<< missing attr: %s\n", #name); \ return -ENOMSG; \ } #undef __field #define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put, \ __is_signed) \ __assign(attr_nr, attr_flag, name, nla_type, type, \ if (s) \ s->name = __get(nla); \ DPRINT_FIELD("<<", nla_type, name, s, nla)) /* validate_nla() already checked nla_len <= maxlen appropriately. */ #undef __array #define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, \ __get, __put, __is_signed) \ __assign(attr_nr, attr_flag, name, nla_type, type, \ if (s) \ s->name ## _len = \ __get(s->name, nla, maxlen); \ DPRINT_ARRAY("<<", nla_type, name, s, nla)) #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 */ static const char *CONCATENATE(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, \ }, #define ZZZ_genl_ops CONCATENATE(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 CONCATENATE(GENL_MAGIC_FAMILY, _genl_family) static struct genl_family ZZZ_genl_family; /* * Magic: define multicast groups * Magic: define multicast group registration helper */ #define ZZZ_genl_mcgrps CONCATENATE(GENL_MAGIC_FAMILY, _genl_mcgrps) static const struct genl_multicast_group ZZZ_genl_mcgrps[] = { #undef GENL_mc_group #define GENL_mc_group(group) { .name = #group, }, #include GENL_MAGIC_INCLUDE_FILE }; enum CONCATENATE(GENL_MAGIC_FAMILY, group_ids) { #undef GENL_mc_group #define GENL_mc_group(group) CONCATENATE(GENL_MAGIC_FAMILY, _group_ ## group), #include GENL_MAGIC_INCLUDE_FILE }; #undef GENL_mc_group #define GENL_mc_group(group) \ static int CONCATENATE(GENL_MAGIC_FAMILY, _genl_multicast_ ## group)( \ struct sk_buff *skb, gfp_t flags) \ { \ unsigned int group_id = \ CONCATENATE(GENL_MAGIC_FAMILY, _group_ ## group); \ return genlmsg_multicast(&ZZZ_genl_family, skb, 0, \ group_id, flags); \ } #include GENL_MAGIC_INCLUDE_FILE #undef GENL_mc_group #define GENL_mc_group(group) static struct genl_family ZZZ_genl_family __ro_after_init = { .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(CONCATENATE(GENL_MAGIC_FAMILY, _tla_nl_policy))-1, .policy = CONCATENATE(GENL_MAGIC_FAMILY, _tla_nl_policy), .ops = ZZZ_genl_ops, .n_ops = ARRAY_SIZE(ZZZ_genl_ops), .mcgrps = ZZZ_genl_mcgrps, .resv_start_op = 42, /* drbd is currently the only user */ .n_mcgrps = ARRAY_SIZE(ZZZ_genl_mcgrps), .module = THIS_MODULE, }; int CONCATENATE(GENL_MAGIC_FAMILY, _genl_register)(void) { return genl_register_family(&ZZZ_genl_family); } void CONCATENATE(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, \ __is_signed) \ if (!exclude_sensitive || !((attr_flag) & DRBD_F_SENSITIVE)) { \ DPRINT_FIELD(">>", nla_type, name, s, NULL); \ if (__put(skb, attr_nr, s->name)) \ goto nla_put_failure; \ } #undef __array #define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, \ __get, __put, __is_signed) \ if (!exclude_sensitive || !((attr_flag) & DRBD_F_SENSITIVE)) { \ DPRINT_ARRAY(">>",nla_type, name, s, NULL); \ if (__put(skb, attr_nr, min_t(int, maxlen, \ s->name ## _len + (nla_type == NLA_NUL_STRING)),\ s->name)) \ goto nla_put_failure; \ } #include GENL_MAGIC_INCLUDE_FILE /* Functions for initializing structs to default values. */ #undef __field #define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put, \ __is_signed) #undef __array #define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, \ __get, __put, __is_signed) #undef __u32_field_def #define __u32_field_def(attr_nr, attr_flag, name, default) \ x->name = default; #undef __s32_field_def #define __s32_field_def(attr_nr, attr_flag, name, default) \ x->name = default; #undef __flg_field_def #define __flg_field_def(attr_nr, attr_flag, name, default) \ x->name = default; #undef __str_field_def #define __str_field_def(attr_nr, attr_flag, name, maxlen) \ memset(x->name, 0, sizeof(x->name)); \ x->name ## _len = 0; #undef GENL_struct #define GENL_struct(tag_name, tag_number, s_name, s_fields) \ static void set_ ## s_name ## _defaults(struct s_name *x) __attribute__((unused)); \ static void set_ ## s_name ## _defaults(struct s_name *x) { \ s_fields \ } #include GENL_MAGIC_INCLUDE_FILE #endif /* __KERNEL__ */ /* }}}1 */ #endif /* GENL_MAGIC_FUNC_H */