731 lines
24 KiB
C
731 lines
24 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2013 Tom Gundersen <teg@jklm.no>
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <linux/rtnetlink.h>
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#include <netinet/in.h>
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#include <netinet/ether.h>
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#include <stdbool.h>
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#include <unistd.h>
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#include "util.h"
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#include "refcnt.h"
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#include "sd-rtnl.h"
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#include "rtnl-internal.h"
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struct sd_rtnl_message {
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RefCount n_ref;
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struct nlmsghdr *hdr;
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struct rtattr *current_container;
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struct rtattr *next_rta;
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size_t remaining_size;
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bool sealed:1;
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};
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static int message_new(sd_rtnl_message **ret, size_t initial_size) {
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sd_rtnl_message *m;
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assert_return(ret, -EINVAL);
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assert_return(initial_size >= sizeof(struct nlmsghdr), -EINVAL);
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m = new0(sd_rtnl_message, 1);
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if (!m)
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return -ENOMEM;
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m->hdr = malloc0(initial_size);
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if (!m->hdr) {
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free(m);
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return -ENOMEM;
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}
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m->n_ref = REFCNT_INIT;
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m->hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
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m->sealed = false;
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*ret = m;
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return 0;
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}
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int message_new_synthetic_error(int error, uint32_t serial, sd_rtnl_message **ret) {
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struct nlmsgerr *err;
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int r;
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assert(error <= 0);
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r = message_new(ret, NLMSG_SPACE(sizeof(struct nlmsgerr)));
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if (r < 0)
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return r;
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(*ret)->hdr->nlmsg_len = NLMSG_LENGTH(sizeof(struct nlmsgerr));
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(*ret)->hdr->nlmsg_type = NLMSG_ERROR;
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(*ret)->hdr->nlmsg_seq = serial;
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err = NLMSG_DATA((*ret)->hdr);
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err->error = error;
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return 0;
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}
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bool message_type_is_route(uint16_t type) {
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switch (type) {
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case RTM_NEWROUTE:
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case RTM_GETROUTE:
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case RTM_DELROUTE:
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return true;
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default:
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return false;
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}
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}
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bool message_type_is_link(uint16_t type) {
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switch (type) {
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case RTM_NEWLINK:
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case RTM_SETLINK:
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case RTM_GETLINK:
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case RTM_DELLINK:
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return true;
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default:
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return false;
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}
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}
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bool message_type_is_addr(uint16_t type) {
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switch (type) {
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case RTM_NEWADDR:
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case RTM_GETADDR:
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case RTM_DELADDR:
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return true;
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default:
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return false;
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}
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}
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int sd_rtnl_message_route_new(uint16_t nlmsg_type, unsigned char rtm_family,
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unsigned char rtm_dst_len, unsigned char rtm_src_len,
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unsigned char rtm_tos, unsigned char rtm_table,
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unsigned char rtm_scope, unsigned char rtm_protocol,
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unsigned char rtm_type, unsigned rtm_flags, sd_rtnl_message **ret) {
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struct rtmsg *rtm;
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int r;
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assert_return(message_type_is_route(nlmsg_type), -EINVAL);
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assert_return(ret, -EINVAL);
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r = message_new(ret, NLMSG_SPACE(sizeof(struct rtmsg)));
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if (r < 0)
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return r;
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(*ret)->hdr->nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
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(*ret)->hdr->nlmsg_type = nlmsg_type;
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if (nlmsg_type == RTM_NEWROUTE)
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(*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_EXCL;
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rtm = NLMSG_DATA((*ret)->hdr);
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rtm->rtm_family = rtm_family;
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rtm->rtm_dst_len = rtm_dst_len;
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rtm->rtm_src_len = rtm_src_len;
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rtm->rtm_tos = rtm_tos;
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rtm->rtm_table = rtm_table;
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rtm->rtm_protocol = rtm_protocol;
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rtm->rtm_scope = rtm_scope;
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rtm->rtm_type = rtm_type;
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rtm->rtm_flags = rtm_flags;
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return 0;
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}
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int sd_rtnl_message_link_set_flags(sd_rtnl_message *m, unsigned flags) {
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struct ifinfomsg *ifi;
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ifi = NLMSG_DATA(m->hdr);
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ifi->ifi_flags = flags;
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return 0;
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}
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int sd_rtnl_message_link_set_type(sd_rtnl_message *m, unsigned type) {
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struct ifinfomsg *ifi;
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ifi = NLMSG_DATA(m->hdr);
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ifi->ifi_type = type;
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return 0;
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}
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int sd_rtnl_message_link_new(uint16_t nlmsg_type, int index, sd_rtnl_message **ret) {
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struct ifinfomsg *ifi;
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int r;
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assert_return(message_type_is_link(nlmsg_type), -EINVAL);
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assert_return(nlmsg_type == RTM_NEWLINK || index > 0, -EINVAL);
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assert_return(ret, -EINVAL);
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r = message_new(ret, NLMSG_SPACE(sizeof(struct ifinfomsg)));
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if (r < 0)
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return r;
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(*ret)->hdr->nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
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(*ret)->hdr->nlmsg_type = nlmsg_type;
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if (nlmsg_type == RTM_NEWLINK)
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(*ret)->hdr->nlmsg_flags |= NLM_F_CREATE;
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ifi = NLMSG_DATA((*ret)->hdr);
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ifi->ifi_family = AF_UNSPEC;
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ifi->ifi_index = index;
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ifi->ifi_change = 0xffffffff;
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return 0;
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}
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int sd_rtnl_message_addr_new(uint16_t nlmsg_type, int index, unsigned char family, unsigned char prefixlen, unsigned char flags, unsigned char scope, sd_rtnl_message **ret) {
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struct ifaddrmsg *ifa;
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int r;
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assert_return(message_type_is_addr(nlmsg_type), -EINVAL);
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assert_return(index > 0, -EINVAL);
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assert_return(ret, -EINVAL);
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r = message_new(ret, NLMSG_SPACE(sizeof(struct ifaddrmsg)));
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if (r < 0)
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return r;
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(*ret)->hdr->nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
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(*ret)->hdr->nlmsg_type = nlmsg_type;
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ifa = NLMSG_DATA((*ret)->hdr);
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ifa->ifa_family = family;
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ifa->ifa_prefixlen = prefixlen;
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ifa->ifa_flags = flags;
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ifa->ifa_scope = scope;
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ifa->ifa_index = index;
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return 0;
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}
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sd_rtnl_message *sd_rtnl_message_ref(sd_rtnl_message *m) {
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if (m)
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assert_se(REFCNT_INC(m->n_ref) >= 2);
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return m;
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}
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sd_rtnl_message *sd_rtnl_message_unref(sd_rtnl_message *m) {
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if (m && REFCNT_DEC(m->n_ref) <= 0) {
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free(m->hdr);
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free(m);
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}
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return NULL;
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}
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int sd_rtnl_message_get_type(sd_rtnl_message *m, uint16_t *type) {
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assert_return(m, -EINVAL);
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assert_return(type, -EINVAL);
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*type = m->hdr->nlmsg_type;
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return 0;
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}
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int sd_rtnl_message_link_get_ifindex(sd_rtnl_message *m, int *ifindex) {
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struct ifinfomsg *ifi;
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assert_return(m, -EINVAL);
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assert_return(m->hdr, -EINVAL);
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assert_return(message_type_is_link(m->hdr->nlmsg_type), -EINVAL);
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assert_return(ifindex, -EINVAL);
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ifi = NLMSG_DATA(m->hdr);
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*ifindex = ifi->ifi_index;
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return 0;
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}
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int sd_rtnl_message_link_get_flags(sd_rtnl_message *m, unsigned *flags) {
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struct ifinfomsg *ifi;
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assert_return(m, -EINVAL);
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assert_return(m->hdr, -EINVAL);
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assert_return(message_type_is_link(m->hdr->nlmsg_type), -EINVAL);
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assert_return(flags, -EINVAL);
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ifi = NLMSG_DATA(m->hdr);
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*flags = ifi->ifi_flags;
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return 0;
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}
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/* If successful the updated message will be correctly aligned, if unsuccessful the old message is
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untouched */
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static int add_rtattr(sd_rtnl_message *m, unsigned short type, const void *data, size_t data_length) {
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uint32_t rta_length, message_length;
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struct nlmsghdr *new_hdr;
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struct rtattr *rta;
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char *padding;
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assert(m);
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assert(m->hdr);
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assert(NLMSG_ALIGN(m->hdr->nlmsg_len) == m->hdr->nlmsg_len);
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assert(!data || data_length > 0);
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/* get the size of the new rta attribute (with padding at the end) */
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rta_length = RTA_LENGTH(data_length);
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/* get the new message size (with padding at the end)
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*/
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message_length = m->hdr->nlmsg_len + RTA_ALIGN(rta_length);
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/* realloc to fit the new attribute */
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new_hdr = realloc(m->hdr, message_length);
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if (!new_hdr)
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return -ENOMEM;
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m->hdr = new_hdr;
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/* get pointer to the attribute we are about to add */
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rta = (struct rtattr *) ((uint8_t *) m->hdr + m->hdr->nlmsg_len);
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/* update message size */
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m->hdr->nlmsg_len = message_length;
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/* we are inside a container, extend it */
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if (m->current_container)
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m->current_container->rta_len = (unsigned char *) m->hdr +
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m->hdr->nlmsg_len -
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(unsigned char *) m->current_container;
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/* fill in the attribute */
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rta->rta_type = type;
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rta->rta_len = rta_length;
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if (!data) {
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/* this is a container, set pointer */
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m->current_container = rta;
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} else {
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/* we don't deal with the case where the user lies about the type
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* and gives us too little data (so don't do that)
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*/
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padding = mempcpy(RTA_DATA(rta), data, data_length);
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/* make sure also the padding at the end of the message is initialized */
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memset(padding, '\0', (unsigned char *) m->hdr +
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m->hdr->nlmsg_len -
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(unsigned char *) padding);
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}
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return 0;
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}
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int sd_rtnl_message_append(sd_rtnl_message *m, unsigned short type, const void *data) {
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uint16_t rtm_type;
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struct ifaddrmsg *ifa;
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struct rtmsg *rtm;
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assert_return(m, -EINVAL);
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assert_return(data, -EINVAL);
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sd_rtnl_message_get_type(m, &rtm_type);
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if (m->current_container) {
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switch (rtm_type) {
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case RTM_NEWLINK:
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case RTM_SETLINK:
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case RTM_GETLINK:
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case RTM_DELLINK:
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switch (m->current_container->rta_type) {
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case IFLA_LINKINFO:
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switch (type) {
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case IFLA_INFO_KIND:
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return add_rtattr(m, type, data, strlen(data) + 1);
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default:
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return -ENOTSUP;
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}
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default:
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return -ENOTSUP;
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}
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default:
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return -ENOTSUP;
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}
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}
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switch (rtm_type) {
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case RTM_NEWLINK:
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case RTM_SETLINK:
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case RTM_DELLINK:
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case RTM_GETLINK:
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switch (type) {
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case IFLA_IFNAME:
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case IFLA_IFALIAS:
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case IFLA_QDISC:
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return add_rtattr(m, type, data, strlen(data) + 1);
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case IFLA_MASTER:
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case IFLA_MTU:
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case IFLA_LINK:
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return add_rtattr(m, type, data, sizeof(uint32_t));
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case IFLA_STATS:
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return add_rtattr(m, type, data, sizeof(struct rtnl_link_stats));
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case IFLA_ADDRESS:
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case IFLA_BROADCAST:
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return add_rtattr(m, type, data, ETH_ALEN);
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default:
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return -ENOTSUP;
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}
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case RTM_NEWADDR:
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case RTM_DELADDR:
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case RTM_GETADDR:
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switch (type) {
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case IFA_LABEL:
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return add_rtattr(m, type, data, strlen(data) + 1);
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case IFA_ADDRESS:
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case IFA_LOCAL:
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case IFA_BROADCAST:
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case IFA_ANYCAST:
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ifa = NLMSG_DATA(m->hdr);
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switch (ifa->ifa_family) {
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case AF_INET:
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return add_rtattr(m, type, data, sizeof(struct in_addr));
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case AF_INET6:
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return add_rtattr(m, type, data, sizeof(struct in6_addr));
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default:
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return -EINVAL;
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}
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default:
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return -ENOTSUP;
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}
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case RTM_NEWROUTE:
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case RTM_DELROUTE:
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case RTM_GETROUTE:
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switch (type) {
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case RTA_DST:
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case RTA_SRC:
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case RTA_GATEWAY:
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rtm = NLMSG_DATA(m->hdr);
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switch (rtm->rtm_family) {
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case AF_INET:
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return add_rtattr(m, type, data, sizeof(struct in_addr));
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case AF_INET6:
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return add_rtattr(m, type, data, sizeof(struct in6_addr));
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default:
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return -EINVAL;
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}
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case RTA_TABLE:
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case RTA_PRIORITY:
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case RTA_IIF:
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case RTA_OIF:
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return add_rtattr(m, type, data, sizeof(uint32_t));
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default:
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return -ENOTSUP;
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}
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default:
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return -ENOTSUP;
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}
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}
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int sd_rtnl_message_open_container(sd_rtnl_message *m, unsigned short type) {
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uint16_t rtm_type;
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assert_return(m, -EINVAL);
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assert_return(!m->current_container, -EINVAL);
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sd_rtnl_message_get_type(m, &rtm_type);
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if (message_type_is_link(rtm_type)) {
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if (type == IFLA_LINKINFO)
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return add_rtattr(m, type, NULL, 0);
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else
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return -ENOTSUP;
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} else
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return -ENOTSUP;
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return 0;
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}
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int sd_rtnl_message_close_container(sd_rtnl_message *m) {
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assert_return(m, -EINVAL);
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assert_return(m->current_container, -EINVAL);
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m->current_container = NULL;
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return 0;
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}
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static int message_read(sd_rtnl_message *m, unsigned short *type, void **data) {
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uint16_t rtm_type;
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int r;
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assert(m);
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assert(m->next_rta);
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assert(type);
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assert(data);
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if (!RTA_OK(m->next_rta, m->remaining_size))
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return 0;
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/* make sure we don't try to read a container
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* TODO: add support for entering containers for reading */
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r = sd_rtnl_message_get_type(m, &rtm_type);
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if (r < 0)
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return r;
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switch (rtm_type) {
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case RTM_NEWLINK:
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case RTM_GETLINK:
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case RTM_SETLINK:
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case RTM_DELLINK:
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if (m->next_rta->rta_type == IFLA_LINKINFO) {
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return -EINVAL;
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}
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}
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*data = RTA_DATA(m->next_rta);
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*type = m->next_rta->rta_type;
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m->next_rta = RTA_NEXT(m->next_rta, m->remaining_size);
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return 1;
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}
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int sd_rtnl_message_read(sd_rtnl_message *m, unsigned short *type, void **data) {
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uint16_t rtm_type;
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int r;
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assert_return(m, -EINVAL);
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assert_return(data, -EINVAL);
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r = sd_rtnl_message_get_type(m, &rtm_type);
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if (r < 0)
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return r;
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switch (rtm_type) {
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case RTM_NEWLINK:
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case RTM_SETLINK:
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case RTM_DELLINK:
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case RTM_GETLINK:
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if (!m->next_rta) {
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struct ifinfomsg *ifi = NLMSG_DATA(m->hdr);
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|
|
m->next_rta = IFLA_RTA(ifi);
|
|
m->remaining_size = IFLA_PAYLOAD(m->hdr);
|
|
}
|
|
break;
|
|
case RTM_NEWADDR:
|
|
case RTM_DELADDR:
|
|
case RTM_GETADDR:
|
|
if (!m->next_rta) {
|
|
struct ifaddrmsg *ifa = NLMSG_DATA(m->hdr);
|
|
|
|
m->next_rta = IFA_RTA(ifa);
|
|
m->remaining_size = IFA_PAYLOAD(m->hdr);
|
|
}
|
|
break;
|
|
case RTM_NEWROUTE:
|
|
case RTM_DELROUTE:
|
|
case RTM_GETROUTE:
|
|
if (!m->next_rta) {
|
|
struct rtmesg *rtm = NLMSG_DATA(m->hdr);
|
|
|
|
m->next_rta = RTM_RTA(rtm);
|
|
m->remaining_size = RTM_PAYLOAD(m->hdr);
|
|
}
|
|
break;
|
|
default:
|
|
return -ENOTSUP;
|
|
}
|
|
|
|
return message_read(m, type, data);
|
|
}
|
|
|
|
uint32_t message_get_serial(sd_rtnl_message *m) {
|
|
assert(m);
|
|
assert(m->hdr);
|
|
|
|
return m->hdr->nlmsg_seq;
|
|
}
|
|
|
|
int sd_rtnl_message_get_errno(sd_rtnl_message *m) {
|
|
struct nlmsgerr *err;
|
|
|
|
assert_return(m, -EINVAL);
|
|
assert_return(m->hdr, -EINVAL);
|
|
|
|
if (m->hdr->nlmsg_type != NLMSG_ERROR)
|
|
return 0;
|
|
|
|
err = NLMSG_DATA(m->hdr);
|
|
|
|
return err->error;
|
|
}
|
|
|
|
int message_seal(sd_rtnl *nl, sd_rtnl_message *m) {
|
|
assert(nl);
|
|
assert(m);
|
|
assert(m->hdr);
|
|
|
|
if (m->sealed)
|
|
return -EPERM;
|
|
|
|
m->hdr->nlmsg_seq = nl->serial++;
|
|
m->sealed = true;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int message_receive_need(sd_rtnl *rtnl, size_t *need) {
|
|
assert(rtnl);
|
|
assert(need);
|
|
|
|
/* ioctl(rtnl->fd, FIONREAD, &need)
|
|
Does not appear to work on netlink sockets. libnl uses
|
|
MSG_PEEK instead. I don't know if that is worth the
|
|
extra roundtrip.
|
|
|
|
For now we simply use the maximum message size the kernel
|
|
may use (NLMSG_GOODSIZE), and then realloc to the actual
|
|
size after reading the message (hence avoiding huge memory
|
|
usage in case many small messages are kept around) */
|
|
*need = page_size();
|
|
if (*need > 8192UL)
|
|
*need = 8192UL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* returns the number of bytes sent, or a negative error code */
|
|
int socket_write_message(sd_rtnl *nl, sd_rtnl_message *m) {
|
|
union {
|
|
struct sockaddr sa;
|
|
struct sockaddr_nl nl;
|
|
} addr = {
|
|
.nl.nl_family = AF_NETLINK,
|
|
};
|
|
ssize_t k;
|
|
|
|
assert(nl);
|
|
assert(m);
|
|
assert(m->hdr);
|
|
|
|
k = sendto(nl->fd, m->hdr, m->hdr->nlmsg_len,
|
|
0, &addr.sa, sizeof(addr));
|
|
if (k < 0)
|
|
return (errno == EAGAIN) ? 0 : -errno;
|
|
|
|
return k;
|
|
}
|
|
|
|
/* On success, the number of bytes received is returned and *ret points to the received message
|
|
* which has a valid header and the correct size.
|
|
* If nothing useful was received 0 is returned.
|
|
* On failure, a negative error code is returned.
|
|
*/
|
|
int socket_read_message(sd_rtnl *nl, sd_rtnl_message **ret) {
|
|
sd_rtnl_message *m;
|
|
union {
|
|
struct sockaddr sa;
|
|
struct sockaddr_nl nl;
|
|
} addr;
|
|
socklen_t addr_len;
|
|
int r;
|
|
ssize_t k;
|
|
size_t need;
|
|
|
|
assert(nl);
|
|
assert(ret);
|
|
|
|
r = message_receive_need(nl, &need);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
r = message_new(&m, need);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
addr_len = sizeof(addr);
|
|
|
|
k = recvfrom(nl->fd, m->hdr, need,
|
|
0, &addr.sa, &addr_len);
|
|
if (k < 0)
|
|
k = (errno == EAGAIN) ? 0 : -errno; /* no data */
|
|
else if (k == 0)
|
|
k = -ECONNRESET; /* connection was closed by the kernel */
|
|
else if (addr_len != sizeof(addr.nl) ||
|
|
addr.nl.nl_family != AF_NETLINK)
|
|
k = -EIO; /* not a netlink message */
|
|
else if (addr.nl.nl_pid != 0)
|
|
k = 0; /* not from the kernel */
|
|
else if ((size_t) k < sizeof(struct nlmsghdr) ||
|
|
(size_t) k < m->hdr->nlmsg_len)
|
|
k = -EIO; /* too small (we do accept too big though) */
|
|
else if (m->hdr->nlmsg_pid && m->hdr->nlmsg_pid != nl->sockaddr.nl.nl_pid)
|
|
k = 0; /* not broadcast and not for us */
|
|
|
|
if (k > 0)
|
|
switch (m->hdr->nlmsg_type) {
|
|
/* check that the size matches the message type */
|
|
case NLMSG_ERROR:
|
|
if (m->hdr->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr)))
|
|
k = -EIO;
|
|
break;
|
|
case RTM_NEWLINK:
|
|
case RTM_SETLINK:
|
|
case RTM_DELLINK:
|
|
case RTM_GETLINK:
|
|
if (m->hdr->nlmsg_len < NLMSG_LENGTH(sizeof(struct ifinfomsg)))
|
|
k = -EIO;
|
|
break;
|
|
case RTM_NEWADDR:
|
|
case RTM_DELADDR:
|
|
case RTM_GETADDR:
|
|
if (m->hdr->nlmsg_len < NLMSG_LENGTH(sizeof(struct ifaddrmsg)))
|
|
k = -EIO;
|
|
break;
|
|
case RTM_NEWROUTE:
|
|
case RTM_DELROUTE:
|
|
case RTM_GETROUTE:
|
|
if (m->hdr->nlmsg_len < NLMSG_LENGTH(sizeof(struct rtmsg)))
|
|
k = -EIO;
|
|
break;
|
|
case NLMSG_NOOP:
|
|
k = 0;
|
|
break;
|
|
default:
|
|
k = 0; /* ignoring message of unknown type */
|
|
}
|
|
|
|
if (k <= 0)
|
|
sd_rtnl_message_unref(m);
|
|
else {
|
|
/* we probably allocated way too much memory, give it back */
|
|
m->hdr = realloc(m->hdr, m->hdr->nlmsg_len);
|
|
*ret = m;
|
|
}
|
|
|
|
return k;
|
|
}
|