| 1 | /* |
| 2 | * lib/genl/mngt.c Generic Netlink Management |
| 3 | * |
| 4 | * This library is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU Lesser General Public |
| 6 | * License as published by the Free Software Foundation version 2.1 |
| 7 | * of the License. |
| 8 | * |
| 9 | * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch> |
| 10 | */ |
| 11 | |
| 12 | /** |
| 13 | * @ingroup genl |
| 14 | * @defgroup genl_mngt Management |
| 15 | * |
| 16 | * @par 1) Registering a generic netlink module |
| 17 | * @code |
| 18 | * #include <netlink/genl/mngt.h> |
| 19 | * |
| 20 | * // First step is to define all the commands being used in |
| 21 | * // particular generic netlink family. The ID and name are |
| 22 | * // mandatory to be filled out. A callback function and |
| 23 | * // most the attribute policy that comes with it must be |
| 24 | * // defined for commands expected to be issued towards |
| 25 | * // userspace. |
| 26 | * static struct genl_cmd foo_cmds[] = { |
| 27 | * { |
| 28 | * .c_id = FOO_CMD_NEW, |
| 29 | * .c_name = "NEWFOO" , |
| 30 | * .c_maxattr = FOO_ATTR_MAX, |
| 31 | * .c_attr_policy = foo_policy, |
| 32 | * .c_msg_parser = foo_msg_parser, |
| 33 | * }, |
| 34 | * { |
| 35 | * .c_id = FOO_CMD_DEL, |
| 36 | * .c_name = "DELFOO" , |
| 37 | * }, |
| 38 | * }; |
| 39 | * |
| 40 | * // The list of commands must then be integrated into a |
| 41 | * // struct genl_ops serving as handle for this particular |
| 42 | * // family. |
| 43 | * static struct genl_ops my_genl_ops = { |
| 44 | * .o_cmds = foo_cmds, |
| 45 | * .o_ncmds = ARRAY_SIZE(foo_cmds), |
| 46 | * }; |
| 47 | * |
| 48 | * // Using the above struct genl_ops an arbitary number of |
| 49 | * // cache handles can be associated to it. |
| 50 | * // |
| 51 | * // The macro GENL_HDRSIZE() must be used to specify the |
| 52 | * // length of the header to automatically take headers on |
| 53 | * // generic layers into account. |
| 54 | * // |
| 55 | * // The macro GENL_FAMILY() is used to represent the generic |
| 56 | * // netlink family id. |
| 57 | * static struct nl_cache_ops genl_foo_ops = { |
| 58 | * .co_name = "genl/foo", |
| 59 | * .co_hdrsize = GENL_HDRSIZE(sizeof(struct my_hdr)), |
| 60 | * .co_msgtypes = GENL_FAMILY(GENL_ID_GENERATE, "foo"), |
| 61 | * .co_genl = &my_genl_ops, |
| 62 | * .co_protocol = NETLINK_GENERIC, |
| 63 | * .co_request_update = foo_request_update, |
| 64 | * .co_obj_ops = &genl_foo_ops, |
| 65 | * }; |
| 66 | * |
| 67 | * // Finally each cache handle for a generic netlink family |
| 68 | * // must be registered using genl_register(). |
| 69 | * static void __init foo_init(void) |
| 70 | * { |
| 71 | * genl_register(&genl_foo_ops); |
| 72 | * } |
| 73 | * |
| 74 | * // ... respectively unregsted again. |
| 75 | * static void __exit foo_exit(void) |
| 76 | * { |
| 77 | * genl_unregister(&genl_foo_ops); |
| 78 | * } |
| 79 | * @endcode |
| 80 | * @{ |
| 81 | */ |
| 82 | |
| 83 | #include <netlink-generic.h> |
| 84 | #include <netlink/netlink.h> |
| 85 | #include <netlink/genl/genl.h> |
| 86 | #include <netlink/genl/mngt.h> |
| 87 | #include <netlink/genl/family.h> |
| 88 | #include <netlink/genl/ctrl.h> |
| 89 | #include <netlink/utils.h> |
| 90 | |
| 91 | static NL_LIST_HEAD(genl_ops_list); |
| 92 | |
| 93 | static int genl_msg_parser(struct nl_cache_ops *ops, struct sockaddr_nl *who, |
| 94 | struct nlmsghdr *nlh, struct nl_parser_param *pp) |
| 95 | { |
| 96 | int i, err; |
| 97 | struct genlmsghdr *ghdr; |
| 98 | struct genl_cmd *cmd; |
| 99 | |
| 100 | ghdr = nlmsg_data(nlh); |
| 101 | |
| 102 | if (ops->co_genl == NULL) |
| 103 | BUG(); |
| 104 | |
| 105 | for (i = 0; i < ops->co_genl->o_ncmds; i++) { |
| 106 | cmd = &ops->co_genl->o_cmds[i]; |
| 107 | if (cmd->c_id == ghdr->cmd) |
| 108 | goto found; |
| 109 | } |
| 110 | |
| 111 | err = -NLE_MSGTYPE_NOSUPPORT; |
| 112 | goto errout; |
| 113 | |
| 114 | found: |
| 115 | if (cmd->c_msg_parser == NULL) |
| 116 | err = -NLE_OPNOTSUPP; |
| 117 | else { |
| 118 | struct nlattr *tb[cmd->c_maxattr + 1]; |
| 119 | struct genl_info info = { |
| 120 | .who = who, |
| 121 | .nlh = nlh, |
| 122 | .genlhdr = ghdr, |
| 123 | .userhdr = genlmsg_data(ghdr), |
| 124 | .attrs = tb, |
| 125 | }; |
| 126 | |
| 127 | err = nlmsg_parse(nlh, ops->co_hdrsize, tb, cmd->c_maxattr, |
| 128 | cmd->c_attr_policy); |
| 129 | if (err < 0) |
| 130 | goto errout; |
| 131 | |
| 132 | err = cmd->c_msg_parser(ops, cmd, &info, pp); |
| 133 | } |
| 134 | errout: |
| 135 | return err; |
| 136 | |
| 137 | } |
| 138 | |
| 139 | char *genl_op2name(int family, int op, char *buf, size_t len) |
| 140 | { |
| 141 | struct genl_ops *ops; |
| 142 | int i; |
| 143 | |
| 144 | nl_list_for_each_entry(ops, &genl_ops_list, o_list) { |
| 145 | if (ops->o_family == family) { |
| 146 | for (i = 0; i < ops->o_ncmds; i++) { |
| 147 | struct genl_cmd *cmd; |
| 148 | cmd = &ops->o_cmds[i]; |
| 149 | |
| 150 | if (cmd->c_id == op) { |
| 151 | strncpy(buf, cmd->c_name, len - 1); |
| 152 | return buf; |
| 153 | } |
| 154 | } |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | strncpy(buf, "unknown", len - 1); |
| 159 | return NULL; |
| 160 | } |
| 161 | |
| 162 | |
| 163 | /** |
| 164 | * @name Register/Unregister |
| 165 | * @{ |
| 166 | */ |
| 167 | |
| 168 | /** |
| 169 | * Register generic netlink operations |
| 170 | * @arg ops cache operations |
| 171 | */ |
| 172 | int genl_register(struct nl_cache_ops *ops) |
| 173 | { |
| 174 | int err; |
| 175 | |
| 176 | if (ops->co_protocol != NETLINK_GENERIC) { |
| 177 | err = -NLE_PROTO_MISMATCH; |
| 178 | goto errout; |
| 179 | } |
| 180 | |
| 181 | if (ops->co_hdrsize < GENL_HDRSIZE(0)) { |
| 182 | err = -NLE_INVAL; |
| 183 | goto errout; |
| 184 | } |
| 185 | |
| 186 | if (ops->co_genl == NULL) { |
| 187 | err = -NLE_INVAL; |
| 188 | goto errout; |
| 189 | } |
| 190 | |
| 191 | ops->co_genl->o_cache_ops = ops; |
| 192 | ops->co_genl->o_name = ops->co_msgtypes[0].mt_name; |
| 193 | ops->co_genl->o_family = ops->co_msgtypes[0].mt_id; |
| 194 | ops->co_msg_parser = genl_msg_parser; |
| 195 | |
| 196 | /* FIXME: check for dup */ |
| 197 | |
| 198 | nl_list_add_tail(&ops->co_genl->o_list, &genl_ops_list); |
| 199 | |
| 200 | err = nl_cache_mngt_register(ops); |
| 201 | errout: |
| 202 | return err; |
| 203 | } |
| 204 | |
| 205 | /** |
| 206 | * Unregister generic netlink operations |
| 207 | * @arg ops cache operations |
| 208 | */ |
| 209 | void genl_unregister(struct nl_cache_ops *ops) |
| 210 | { |
| 211 | nl_cache_mngt_unregister(ops); |
| 212 | nl_list_del(&ops->co_genl->o_list); |
| 213 | } |
| 214 | |
| 215 | /** @} */ |
| 216 | |
| 217 | /** |
| 218 | * @name Resolving ID/Name |
| 219 | * @{ |
| 220 | */ |
| 221 | #ifdef disabled |
| 222 | static int __genl_ops_resolve(struct nl_cache *ctrl, struct genl_ops *ops) |
| 223 | { |
| 224 | struct genl_family *family; |
| 225 | |
| 226 | family = genl_ctrl_search_by_name(ctrl, ops->o_name); |
| 227 | if (family != NULL) { |
| 228 | ops->o_id = genl_family_get_id(family); |
| 229 | genl_family_put(family); |
| 230 | |
| 231 | return 0; |
| 232 | } |
| 233 | |
| 234 | return -NLE_OBJ_NOTFOUND; |
| 235 | } |
| 236 | |
| 237 | int genl_ops_resolve(struct nl_sock *sk, struct genl_ops *ops) |
| 238 | { |
| 239 | struct nl_cache *ctrl; |
| 240 | int err; |
| 241 | |
| 242 | if ((err = genl_ctrl_alloc_cache(sk, &ctrl)) < 0) |
| 243 | goto errout; |
| 244 | |
| 245 | err = __genl_ops_resolve(ctrl, ops); |
| 246 | |
| 247 | nl_cache_free(ctrl); |
| 248 | errout: |
| 249 | return err; |
| 250 | } |
| 251 | |
| 252 | int genl_mngt_resolve(struct nl_sock *sk) |
| 253 | { |
| 254 | struct nl_cache *ctrl; |
| 255 | struct genl_ops *ops; |
| 256 | int err = 0; |
| 257 | |
| 258 | if ((err = genl_ctrl_alloc_cache(sk, &ctrl)) < 0) |
| 259 | goto errout; |
| 260 | |
| 261 | nl_list_for_each_entry(ops, &genl_ops_list, o_list) { |
| 262 | err = __genl_ops_resolve(ctrl, ops); |
| 263 | } |
| 264 | |
| 265 | nl_cache_free(ctrl); |
| 266 | errout: |
| 267 | return err; |
| 268 | } |
| 269 | #endif |
| 270 | /** @} */ |
| 271 | |
| 272 | |
| 273 | /** @} */ |
| 274 | |
