175 lines
4.1 KiB
C
175 lines
4.1 KiB
C
/* Generic Netlink helper functions */
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/* (C) 2014 by sysmocom - s.f.m.c. GmbH
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* Author: Pablo Neira Ayuso <pablo@gnumonks.org>
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*
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation; either version 2.1 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <time.h>
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#include <libmnl/libmnl.h>
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#include <linux/genetlink.h>
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#include <libgtpnl/gtpnl.h>
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#include "internal.h"
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struct nlmsghdr *
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genl_nlmsg_build_hdr(char *buf, uint16_t type, uint16_t flags, uint32_t seq,
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uint8_t cmd)
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{
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struct nlmsghdr *nlh;
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struct genlmsghdr *genl;
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nlh = mnl_nlmsg_put_header(buf);
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nlh->nlmsg_type = type;
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nlh->nlmsg_flags = NLM_F_REQUEST | flags;
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nlh->nlmsg_seq = seq;
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genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr));
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genl->cmd = cmd;
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genl->version = 0;
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return nlh;
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}
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EXPORT_SYMBOL(genl_nlmsg_build_hdr);
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static int genl_ctrl_validate_cb(const struct nlattr *attr, void *data)
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{
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const struct nlattr **tb = data;
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int type = mnl_attr_get_type(attr);
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if (mnl_attr_type_valid(attr, CTRL_ATTR_MAX) < 0)
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return MNL_CB_OK;
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switch(type) {
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case CTRL_ATTR_FAMILY_ID:
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if (mnl_attr_validate(attr, MNL_TYPE_U16) < 0) {
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perror("mnl_attr_validate");
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return MNL_CB_ERROR;
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}
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break;
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}
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tb[type] = attr;
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return MNL_CB_OK;
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}
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static int genl_ctrl_cb(const struct nlmsghdr *nlh, void *data)
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{
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struct nlattr *tb[CTRL_ATTR_MAX + 1] = {};
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struct genlmsghdr *genl = mnl_nlmsg_get_payload(nlh);
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int32_t *genl_id = data;
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mnl_attr_parse(nlh, sizeof(*genl), genl_ctrl_validate_cb, tb);
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if (tb[CTRL_ATTR_FAMILY_ID])
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*genl_id = mnl_attr_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
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else
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*genl_id = -1;
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return MNL_CB_OK;
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}
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struct mnl_socket *genl_socket_open(void)
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{
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struct mnl_socket *nl;
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nl = mnl_socket_open(NETLINK_GENERIC);
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if (nl == NULL) {
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perror("mnl_socket_open");
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return NULL;
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}
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if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
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perror("mnl_socket_bind");
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return NULL;
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}
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return nl;
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}
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EXPORT_SYMBOL(genl_socket_open);
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void genl_socket_close(struct mnl_socket *nl)
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{
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mnl_socket_close(nl);
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}
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EXPORT_SYMBOL(genl_socket_close);
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int genl_socket_talk(struct mnl_socket *nl, struct nlmsghdr *nlh, uint32_t seq,
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int (*cb)(const struct nlmsghdr *nlh, void *data),
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void *data)
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{
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char buf[MNL_SOCKET_BUFFER_SIZE];
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int ret;
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if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
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perror("mnl_socket_send");
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return -1;
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}
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ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
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while (ret > 0) {
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ret = mnl_cb_run(buf, ret, seq, mnl_socket_get_portid(nl),
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cb, data);
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if (ret <= 0)
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break;
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ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
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}
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return ret;
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}
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EXPORT_SYMBOL(genl_socket_talk);
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static struct nlmsghdr *
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genl_nlmsg_build_lookup(char *buf, const char *subsys_name)
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{
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struct nlmsghdr *nlh;
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struct genlmsghdr *genl;
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nlh = mnl_nlmsg_put_header(buf);
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nlh->nlmsg_type = GENL_ID_CTRL;
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nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
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nlh->nlmsg_seq = time(NULL);
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genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr));
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genl->cmd = CTRL_CMD_GETFAMILY;
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genl->version = 1;
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mnl_attr_put_u16(nlh, CTRL_ATTR_FAMILY_ID, GENL_ID_CTRL);
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mnl_attr_put_strz(nlh, CTRL_ATTR_FAMILY_NAME, subsys_name);
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return nlh;
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}
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int genl_lookup_family(struct mnl_socket *nl, const char *family)
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{
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int32_t genl_id;
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char buf[MNL_SOCKET_BUFFER_SIZE];
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struct nlmsghdr *nlh = genl_nlmsg_build_lookup(buf, "gtp");
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int err;
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err = genl_socket_talk(nl, nlh, nlh->nlmsg_seq, genl_ctrl_cb, &genl_id);
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if (err < 0)
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return -1;
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return genl_id;
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}
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EXPORT_SYMBOL(genl_lookup_family);
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