Richard Alpe | f043759 | 2015-05-07 15:07:36 +0200 | [diff] [blame] | 1 | /* |
| 2 | * msg.c Messaging (netlink) helper functions. |
| 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: Richard Alpe <richard.alpe@ericsson.com> |
| 10 | */ |
| 11 | |
| 12 | #include <stdio.h> |
| 13 | #include <time.h> |
| 14 | #include <errno.h> |
| 15 | |
| 16 | #include <linux/tipc_netlink.h> |
| 17 | #include <linux/tipc.h> |
| 18 | #include <linux/genetlink.h> |
| 19 | #include <libmnl/libmnl.h> |
| 20 | |
| 21 | #include "msg.h" |
| 22 | |
| 23 | int parse_attrs(const struct nlattr *attr, void *data) |
| 24 | { |
| 25 | const struct nlattr **tb = data; |
| 26 | int type = mnl_attr_get_type(attr); |
| 27 | |
| 28 | tb[type] = attr; |
| 29 | |
| 30 | return MNL_CB_OK; |
| 31 | } |
| 32 | |
| 33 | static int family_id_cb(const struct nlmsghdr *nlh, void *data) |
| 34 | { |
| 35 | struct nlattr *tb[CTRL_ATTR_MAX + 1] = {}; |
| 36 | struct genlmsghdr *genl = mnl_nlmsg_get_payload(nlh); |
| 37 | int *id = data; |
| 38 | |
| 39 | mnl_attr_parse(nlh, sizeof(*genl), parse_attrs, tb); |
| 40 | if (!tb[CTRL_ATTR_FAMILY_ID]) |
| 41 | return MNL_CB_ERROR; |
| 42 | |
| 43 | *id = mnl_attr_get_u16(tb[CTRL_ATTR_FAMILY_ID]); |
| 44 | |
| 45 | return MNL_CB_OK; |
| 46 | } |
| 47 | |
| 48 | static struct mnl_socket *msg_send(struct nlmsghdr *nlh) |
| 49 | { |
| 50 | int ret; |
| 51 | struct mnl_socket *nl; |
| 52 | |
| 53 | nl = mnl_socket_open(NETLINK_GENERIC); |
| 54 | if (nl == NULL) { |
| 55 | perror("mnl_socket_open"); |
| 56 | return NULL; |
| 57 | } |
| 58 | |
| 59 | ret = mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID); |
| 60 | if (ret < 0) { |
| 61 | perror("mnl_socket_bind"); |
| 62 | return NULL; |
| 63 | } |
| 64 | |
| 65 | ret = mnl_socket_sendto(nl, nlh, nlh->nlmsg_len); |
| 66 | if (ret < 0) { |
| 67 | perror("mnl_socket_send"); |
| 68 | return NULL; |
| 69 | } |
| 70 | |
| 71 | return nl; |
| 72 | } |
| 73 | |
| 74 | static int msg_recv(struct mnl_socket *nl, mnl_cb_t callback, void *data, int seq) |
| 75 | { |
| 76 | int ret; |
| 77 | unsigned int portid; |
| 78 | char buf[MNL_SOCKET_BUFFER_SIZE]; |
| 79 | |
| 80 | portid = mnl_socket_get_portid(nl); |
| 81 | |
| 82 | ret = mnl_socket_recvfrom(nl, buf, sizeof(buf)); |
| 83 | while (ret > 0) { |
| 84 | ret = mnl_cb_run(buf, ret, seq, portid, callback, data); |
| 85 | if (ret <= 0) |
| 86 | break; |
| 87 | ret = mnl_socket_recvfrom(nl, buf, sizeof(buf)); |
| 88 | } |
| 89 | if (ret == -1) |
| 90 | perror("error"); |
| 91 | |
| 92 | mnl_socket_close(nl); |
| 93 | |
| 94 | return ret; |
| 95 | } |
| 96 | |
| 97 | static int msg_query(struct nlmsghdr *nlh, mnl_cb_t callback, void *data) |
| 98 | { |
| 99 | unsigned int seq; |
| 100 | struct mnl_socket *nl; |
| 101 | |
| 102 | seq = time(NULL); |
| 103 | nlh->nlmsg_seq = seq; |
| 104 | |
| 105 | nl = msg_send(nlh); |
| 106 | if (!nl) |
| 107 | return -ENOTSUP; |
| 108 | |
| 109 | return msg_recv(nl, callback, data, seq); |
| 110 | } |
| 111 | |
| 112 | static int get_family(void) |
| 113 | { |
| 114 | int err; |
| 115 | int nl_family; |
| 116 | struct nlmsghdr *nlh; |
| 117 | struct genlmsghdr *genl; |
| 118 | char buf[MNL_SOCKET_BUFFER_SIZE]; |
| 119 | |
| 120 | nlh = mnl_nlmsg_put_header(buf); |
| 121 | nlh->nlmsg_type = GENL_ID_CTRL; |
| 122 | nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK; |
| 123 | |
| 124 | genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr)); |
| 125 | genl->cmd = CTRL_CMD_GETFAMILY; |
| 126 | genl->version = 1; |
| 127 | |
| 128 | mnl_attr_put_u32(nlh, CTRL_ATTR_FAMILY_ID, GENL_ID_CTRL); |
| 129 | mnl_attr_put_strz(nlh, CTRL_ATTR_FAMILY_NAME, TIPC_GENL_V2_NAME); |
| 130 | |
| 131 | if ((err = msg_query(nlh, family_id_cb, &nl_family))) |
| 132 | return err; |
| 133 | |
| 134 | return nl_family; |
| 135 | } |
| 136 | |
| 137 | int msg_doit(struct nlmsghdr *nlh, mnl_cb_t callback, void *data) |
| 138 | { |
| 139 | nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK; |
| 140 | return msg_query(nlh, callback, data); |
| 141 | } |
| 142 | |
| 143 | int msg_dumpit(struct nlmsghdr *nlh, mnl_cb_t callback, void *data) |
| 144 | { |
| 145 | nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP; |
| 146 | return msg_query(nlh, callback, data); |
| 147 | } |
| 148 | |
| 149 | struct nlmsghdr *msg_init(char *buf, int cmd) |
| 150 | { |
| 151 | int family; |
| 152 | struct nlmsghdr *nlh; |
| 153 | struct genlmsghdr *genl; |
| 154 | |
| 155 | family = get_family(); |
| 156 | if (family <= 0) { |
| 157 | fprintf(stderr, |
| 158 | "Unable to get TIPC nl family id (module loaded?)\n"); |
| 159 | return NULL; |
| 160 | } |
| 161 | |
| 162 | nlh = mnl_nlmsg_put_header(buf); |
| 163 | nlh->nlmsg_type = family; |
| 164 | |
| 165 | genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr)); |
| 166 | genl->cmd = cmd; |
| 167 | genl->version = 1; |
| 168 | |
| 169 | return nlh; |
| 170 | } |