devlink/mnlg.c

   1 /*
   2  *   mnlg.c     Generic Netlink helpers for libmnl
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Jiri Pirko <jiri@mellanox.com>
  10  */
  11
  12 #include <stdlib.h>
  13 #include <stdbool.h>
  14 #include <string.h>
  15 #include <errno.h>
  16 #include <unistd.h>
  17 #include <time.h>
  18 #include <libmnl/libmnl.h>
  19 #include <linux/genetlink.h>
  20
  21 #include "libnetlink.h"
  22 #include "utils.h"
  23 #include "mnlg.h"
  24
  25 struct mnlg_socket {
  26         struct mnl_socket *nl;
  27         char *buf;
  28         uint32_t id;
  29         uint8_t version;
  30         unsigned int seq;
  31         unsigned int portid;
  32 };
  33
  34 static struct nlmsghdr *__mnlg_msg_prepare(struct mnlg_socket *nlg, uint8_t cmd,
  35                                            uint16_t flags, uint32_t id,
  36                                            uint8_t version)
  37 {
  38         struct nlmsghdr *nlh;
  39         struct genlmsghdr *genl;
  40
  41         nlh = mnl_nlmsg_put_header(nlg->buf);
  42         nlh->nlmsg_type = id;
  43         nlh->nlmsg_flags = flags;
  44         nlg->seq = time(NULL);
  45         nlh->nlmsg_seq = nlg->seq;
  46
  47         genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr));
  48         genl->cmd = cmd;
  49         genl->version = version;
  50
  51         return nlh;
  52 }
  53
  54 struct nlmsghdr *mnlg_msg_prepare(struct mnlg_socket *nlg, uint8_t cmd,
  55                                   uint16_t flags)
  56 {
  57         return __mnlg_msg_prepare(nlg, cmd, flags, nlg->id, nlg->version);
  58 }
  59
  60 int mnlg_socket_send(struct mnlg_socket *nlg, const struct nlmsghdr *nlh)
  61 {
  62         return mnl_socket_sendto(nlg->nl, nlh, nlh->nlmsg_len);
  63 }
  64
  65 static int mnlg_cb_noop(const struct nlmsghdr *nlh, void *data)
  66 {
  67         return MNL_CB_OK;
  68 }
  69
  70 static int mnlg_cb_error(const struct nlmsghdr *nlh, void *data)
  71 {
  72         const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh);
  73
  74         /* Netlink subsystems returns the errno value with different signess */
  75         if (err->error < 0)
  76                 errno = -err->error;
  77         else
  78                 errno = err->error;
  79
  80         if (nl_dump_ext_ack(nlh, NULL))
  81                 return MNL_CB_ERROR;
  82
  83         return err->error == 0 ? MNL_CB_STOP : MNL_CB_ERROR;
  84 }
  85
  86 static int mnlg_cb_stop(const struct nlmsghdr *nlh, void *data)
  87 {
  88         return MNL_CB_STOP;
  89 }
  90
  91 static mnl_cb_t mnlg_cb_array[NLMSG_MIN_TYPE] = {
  92         [NLMSG_NOOP]    = mnlg_cb_noop,
  93         [NLMSG_ERROR]   = mnlg_cb_error,
  94         [NLMSG_DONE]    = mnlg_cb_stop,
  95         [NLMSG_OVERRUN] = mnlg_cb_noop,
  96 };
  97
  98 int mnlg_socket_recv_run(struct mnlg_socket *nlg, mnl_cb_t data_cb, void *data)
  99 {
 100         int err;
 101
 102         do {
 103                 err = mnl_socket_recvfrom(nlg->nl, nlg->buf,
 104                                           MNL_SOCKET_BUFFER_SIZE);
 105                 if (err <= 0)
 106                         break;
 107                 err = mnl_cb_run2(nlg->buf, err, nlg->seq, nlg->portid,
 108                                   data_cb, data, mnlg_cb_array,
 109                                   ARRAY_SIZE(mnlg_cb_array));
 110         } while (err > 0);
 111
 112         return err;
 113 }
 114
 115 struct group_info {
 116         bool found;
 117         uint32_t id;
 118         const char *name;
 119 };
 120
 121 static int parse_mc_grps_cb(const struct nlattr *attr, void *data)
 122 {
 123         const struct nlattr **tb = data;
 124         int type = mnl_attr_get_type(attr);
 125
 126         if (mnl_attr_type_valid(attr, CTRL_ATTR_MCAST_GRP_MAX) < 0)
 127                 return MNL_CB_OK;
 128
 129         switch (type) {
 130         case CTRL_ATTR_MCAST_GRP_ID:
 131                 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
 132                         return MNL_CB_ERROR;
 133                 break;
 134         case CTRL_ATTR_MCAST_GRP_NAME:
 135                 if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
 136                         return MNL_CB_ERROR;
 137                 break;
 138         }
 139         tb[type] = attr;
 140         return MNL_CB_OK;
 141 }
 142
 143 static void parse_genl_mc_grps(struct nlattr *nested,
 144                                struct group_info *group_info)
 145 {
 146         struct nlattr *pos;
 147         const char *name;
 148
 149         mnl_attr_for_each_nested(pos, nested) {
 150                 struct nlattr *tb[CTRL_ATTR_MCAST_GRP_MAX + 1] = {};
 151
 152                 mnl_attr_parse_nested(pos, parse_mc_grps_cb, tb);
 153                 if (!tb[CTRL_ATTR_MCAST_GRP_NAME] ||
 154                     !tb[CTRL_ATTR_MCAST_GRP_ID])
 155                         continue;
 156
 157                 name = mnl_attr_get_str(tb[CTRL_ATTR_MCAST_GRP_NAME]);
 158                 if (strcmp(name, group_info->name) != 0)
 159                         continue;
 160
 161                 group_info->id = mnl_attr_get_u32(tb[CTRL_ATTR_MCAST_GRP_ID]);
 162                 group_info->found = true;
 163         }
 164 }
 165
 166 static int get_group_id_attr_cb(const struct nlattr *attr, void *data)
 167 {
 168         const struct nlattr **tb = data;
 169         int type = mnl_attr_get_type(attr);
 170
 171         if (mnl_attr_type_valid(attr, CTRL_ATTR_MAX) < 0)
 172                 return MNL_CB_ERROR;
 173
 174         if (type == CTRL_ATTR_MCAST_GROUPS &&
 175             mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0)
 176                 return MNL_CB_ERROR;
 177         tb[type] = attr;
 178         return MNL_CB_OK;
 179 }
 180
 181 static int get_group_id_cb(const struct nlmsghdr *nlh, void *data)
 182 {
 183         struct group_info *group_info = data;
 184         struct nlattr *tb[CTRL_ATTR_MAX + 1] = {};
 185         struct genlmsghdr *genl = mnl_nlmsg_get_payload(nlh);
 186
 187         mnl_attr_parse(nlh, sizeof(*genl), get_group_id_attr_cb, tb);
 188         if (!tb[CTRL_ATTR_MCAST_GROUPS])
 189                 return MNL_CB_ERROR;
 190         parse_genl_mc_grps(tb[CTRL_ATTR_MCAST_GROUPS], group_info);
 191         return MNL_CB_OK;
 192 }
 193
 194 int mnlg_socket_group_add(struct mnlg_socket *nlg, const char *group_name)
 195 {
 196         struct nlmsghdr *nlh;
 197         struct group_info group_info;
 198         int err;
 199
 200         nlh = __mnlg_msg_prepare(nlg, CTRL_CMD_GETFAMILY,
 201                                  NLM_F_REQUEST | NLM_F_ACK, GENL_ID_CTRL, 1);
 202         mnl_attr_put_u16(nlh, CTRL_ATTR_FAMILY_ID, nlg->id);
 203
 204         err = mnlg_socket_send(nlg, nlh);
 205         if (err < 0)
 206                 return err;
 207
 208         group_info.found = false;
 209         group_info.name = group_name;
 210         err = mnlg_socket_recv_run(nlg, get_group_id_cb, &group_info);
 211         if (err < 0)
 212                 return err;
 213
 214         if (!group_info.found) {
 215                 errno = ENOENT;
 216                 return -1;
 217         }
 218
 219         err = mnl_socket_setsockopt(nlg->nl, NETLINK_ADD_MEMBERSHIP,
 220                                     &group_info.id, sizeof(group_info.id));
 221         if (err < 0)
 222                 return err;
 223
 224         return 0;
 225 }
 226
 227 static int get_family_id_attr_cb(const struct nlattr *attr, void *data)
 228 {
 229         const struct nlattr **tb = data;
 230         int type = mnl_attr_get_type(attr);
 231
 232         if (mnl_attr_type_valid(attr, CTRL_ATTR_MAX) < 0)
 233                 return MNL_CB_ERROR;
 234
 235         if (type == CTRL_ATTR_FAMILY_ID &&
 236             mnl_attr_validate(attr, MNL_TYPE_U16) < 0)
 237                 return MNL_CB_ERROR;
 238         tb[type] = attr;
 239         return MNL_CB_OK;
 240 }
 241
 242 static int get_family_id_cb(const struct nlmsghdr *nlh, void *data)
 243 {
 244         uint32_t *p_id = data;
 245         struct nlattr *tb[CTRL_ATTR_MAX + 1] = {};
 246         struct genlmsghdr *genl = mnl_nlmsg_get_payload(nlh);
 247
 248         mnl_attr_parse(nlh, sizeof(*genl), get_family_id_attr_cb, tb);
 249         if (!tb[CTRL_ATTR_FAMILY_ID])
 250                 return MNL_CB_ERROR;
 251         *p_id = mnl_attr_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
 252         return MNL_CB_OK;
 253 }
 254
 255 struct mnlg_socket *mnlg_socket_open(const char *family_name, uint8_t version)
 256 {
 257         struct mnlg_socket *nlg;
 258         struct nlmsghdr *nlh;
 259         int one = 1;
 260         int err;
 261
 262         nlg = malloc(sizeof(*nlg));
 263         if (!nlg)
 264                 return NULL;
 265
 266         nlg->buf = malloc(MNL_SOCKET_BUFFER_SIZE);
 267         if (!nlg->buf)
 268                 goto err_buf_alloc;
 269
 270         nlg->nl = mnl_socket_open(NETLINK_GENERIC);
 271         if (!nlg->nl)
 272                 goto err_mnl_socket_open;
 273
 274         /* Older kernels may no support capped/extended ACK reporting */
 275         mnl_socket_setsockopt(nlg->nl, NETLINK_CAP_ACK, &one, sizeof(one));
 276         mnl_socket_setsockopt(nlg->nl, NETLINK_EXT_ACK, &one, sizeof(one));
 277
 278         err = mnl_socket_bind(nlg->nl, 0, MNL_SOCKET_AUTOPID);
 279         if (err < 0)
 280                 goto err_mnl_socket_bind;
 281
 282         nlg->portid = mnl_socket_get_portid(nlg->nl);
 283
 284         nlh = __mnlg_msg_prepare(nlg, CTRL_CMD_GETFAMILY,
 285                                  NLM_F_REQUEST | NLM_F_ACK, GENL_ID_CTRL, 1);
 286         mnl_attr_put_strz(nlh, CTRL_ATTR_FAMILY_NAME, family_name);
 287
 288         err = mnlg_socket_send(nlg, nlh);
 289         if (err < 0)
 290                 goto err_mnlg_socket_send;
 291
 292         err = mnlg_socket_recv_run(nlg, get_family_id_cb, &nlg->id);
 293         if (err < 0)
 294                 goto err_mnlg_socket_recv_run;
 295
 296         nlg->version = version;
 297         return nlg;
 298
 299 err_mnlg_socket_recv_run:
 300 err_mnlg_socket_send:
 301 err_mnl_socket_bind:
 302         mnl_socket_close(nlg->nl);
 303 err_mnl_socket_open:
 304         free(nlg->buf);
 305 err_buf_alloc:
 306         free(nlg);
 307         return NULL;
 308 }
 309
 310 void mnlg_socket_close(struct mnlg_socket *nlg)
 311 {
 312         mnl_socket_close(nlg->nl);
 313         free(nlg->buf);
 314         free(nlg);
 315 }