rtnl-message.c revision d595c5cc9e894c3608ed634052b0ba93aa94bf2f
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2013 Tom Gundersen <teg@jklm.no>
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <linux/rtnetlink.h>
#include <netinet/in.h>
#include <netinet/ether.h>
#include <stdbool.h>
#include <unistd.h>
#include "util.h"
#include "refcnt.h"
#include "sd-rtnl.h"
#include "rtnl-util.h"
#include "rtnl-internal.h"
#define GET_CONTAINER(m, i) (i < (m)->n_containers ? (struct rtattr*)((uint8_t*)(m)->hdr + (m)->container_offsets[i]) : NULL)
#define NEXT_RTA(m) ((struct rtattr*)((uint8_t*)(m)->hdr + (m)->next_rta_offset))
#define UPDATE_RTA(m, new) (m)->next_rta_offset = (uint8_t*)(new) - (uint8_t*)(m)->hdr;
#define PUSH_CONTAINER(m, new) (m)->container_offsets[(m)->n_containers ++] = (uint8_t*)(new) - (uint8_t*)(m)->hdr;
int message_new(sd_rtnl_message **ret, size_t initial_size) {
sd_rtnl_message *m;
assert_return(ret, -EINVAL);
assert_return(initial_size >= sizeof(struct nlmsghdr), -EINVAL);
m = new0(sd_rtnl_message, 1);
if (!m)
return -ENOMEM;
m->hdr = malloc0(initial_size);
if (!m->hdr) {
free(m);
return -ENOMEM;
}
m->n_ref = REFCNT_INIT;
m->hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
m->sealed = false;
*ret = m;
return 0;
}
int sd_rtnl_message_route_set_dst_prefixlen(sd_rtnl_message *m, unsigned char prefixlen) {
struct rtmsg *rtm;
assert_return(m, -EINVAL);
assert_return(m->hdr, -EINVAL);
assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
rtm = NLMSG_DATA(m->hdr);
if ((rtm->rtm_family == AF_INET && prefixlen > 32) ||
(rtm->rtm_family == AF_INET6 && prefixlen > 128))
return -ERANGE;
rtm->rtm_dst_len = prefixlen;
return 0;
}
int sd_rtnl_message_new_route(uint16_t nlmsg_type, unsigned char rtm_family,
sd_rtnl_message **ret) {
struct rtmsg *rtm;
int r;
assert_return(rtnl_message_type_is_route(nlmsg_type), -EINVAL);
assert_return(rtm_family == AF_INET || rtm_family == AF_INET6, -EINVAL);
assert_return(ret, -EINVAL);
r = message_new(ret, NLMSG_SPACE(sizeof(struct rtmsg)));
if (r < 0)
return r;
(*ret)->hdr->nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
(*ret)->hdr->nlmsg_type = nlmsg_type;
if (nlmsg_type == RTM_NEWROUTE)
(*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_EXCL;
rtm = NLMSG_DATA((*ret)->hdr);
UPDATE_RTA(*ret, RTM_RTA(rtm));
rtm->rtm_family = rtm_family;
rtm->rtm_scope = RT_SCOPE_UNIVERSE;
rtm->rtm_type = RTN_UNICAST;
rtm->rtm_table = RT_TABLE_MAIN;
rtm->rtm_protocol = RTPROT_BOOT;
return 0;
}
int sd_rtnl_message_link_set_flags(sd_rtnl_message *m, unsigned flags, unsigned change) {
struct ifinfomsg *ifi;
assert_return(m, -EINVAL);
assert_return(m->hdr, -EINVAL);
assert_return(rtnl_message_type_is_link(m->hdr->nlmsg_type), -EINVAL);
ifi = NLMSG_DATA(m->hdr);
ifi->ifi_flags = flags;
if (change)
ifi->ifi_change = change;
else
ifi->ifi_change = 0xffffffff;
return 0;
}
int sd_rtnl_message_link_set_type(sd_rtnl_message *m, unsigned type) {
struct ifinfomsg *ifi;
assert_return(m, -EINVAL);
assert_return(m->hdr, -EINVAL);
assert_return(rtnl_message_type_is_link(m->hdr->nlmsg_type), -EINVAL);
ifi = NLMSG_DATA(m->hdr);
ifi->ifi_type = type;
return 0;
}
int sd_rtnl_message_new_link(uint16_t nlmsg_type, int index, sd_rtnl_message **ret) {
struct ifinfomsg *ifi;
int r;
assert_return(rtnl_message_type_is_link(nlmsg_type), -EINVAL);
assert_return(nlmsg_type == RTM_NEWLINK || index > 0, -EINVAL);
assert_return(ret, -EINVAL);
r = message_new(ret, NLMSG_SPACE(sizeof(struct ifinfomsg)));
if (r < 0)
return r;
(*ret)->hdr->nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
(*ret)->hdr->nlmsg_type = nlmsg_type;
if (nlmsg_type == RTM_NEWLINK)
(*ret)->hdr->nlmsg_flags |= NLM_F_CREATE;
ifi = NLMSG_DATA((*ret)->hdr);
ifi->ifi_family = AF_UNSPEC;
ifi->ifi_index = index;
UPDATE_RTA(*ret, IFLA_RTA(ifi));
return 0;
}
int sd_rtnl_message_addr_set_prefixlen(sd_rtnl_message *m, unsigned char prefixlen) {
struct ifaddrmsg *ifa;
assert_return(m, -EINVAL);
assert_return(m->hdr, -EINVAL);
assert_return(rtnl_message_type_is_addr(m->hdr->nlmsg_type), -EINVAL);
ifa = NLMSG_DATA(m->hdr);
if ((ifa->ifa_family == AF_INET && prefixlen > 32) ||
(ifa->ifa_family == AF_INET6 && prefixlen > 128))
return -ERANGE;
ifa->ifa_prefixlen = prefixlen;
return 0;
}
int sd_rtnl_message_addr_set_flags(sd_rtnl_message *m, unsigned char flags) {
struct ifaddrmsg *ifa;
assert_return(m, -EINVAL);
assert_return(m->hdr, -EINVAL);
assert_return(rtnl_message_type_is_addr(m->hdr->nlmsg_type), -EINVAL);
ifa = NLMSG_DATA(m->hdr);
ifa->ifa_flags = flags;
return 0;
}
int sd_rtnl_message_addr_set_scope(sd_rtnl_message *m, unsigned char scope) {
struct ifaddrmsg *ifa;
assert_return(m, -EINVAL);
assert_return(m->hdr, -EINVAL);
assert_return(rtnl_message_type_is_addr(m->hdr->nlmsg_type), -EINVAL);
ifa = NLMSG_DATA(m->hdr);
ifa->ifa_scope = scope;
return 0;
}
int sd_rtnl_message_new_addr(uint16_t nlmsg_type, int index, unsigned char family,
sd_rtnl_message **ret) {
struct ifaddrmsg *ifa;
int r;
assert_return(rtnl_message_type_is_addr(nlmsg_type), -EINVAL);
assert_return(index > 0, -EINVAL);
assert_return(family == AF_INET || family == AF_INET6, -EINVAL);
assert_return(ret, -EINVAL);
r = message_new(ret, NLMSG_SPACE(sizeof(struct ifaddrmsg)));
if (r < 0)
return r;
(*ret)->hdr->nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
(*ret)->hdr->nlmsg_type = nlmsg_type;
ifa = NLMSG_DATA((*ret)->hdr);
ifa->ifa_index = index;
ifa->ifa_family = family;
if (family == AF_INET)
ifa->ifa_prefixlen = 32;
else if (family == AF_INET6)
ifa->ifa_prefixlen = 128;
UPDATE_RTA(*ret, IFA_RTA(ifa));
return 0;
}
sd_rtnl_message *sd_rtnl_message_ref(sd_rtnl_message *m) {
if (m)
assert_se(REFCNT_INC(m->n_ref) >= 2);
return m;
}
sd_rtnl_message *sd_rtnl_message_unref(sd_rtnl_message *m) {
if (m && REFCNT_DEC(m->n_ref) <= 0) {
free(m->hdr);
free(m);
}
return NULL;
}
int sd_rtnl_message_get_type(sd_rtnl_message *m, uint16_t *type) {
assert_return(m, -EINVAL);
assert_return(type, -EINVAL);
*type = m->hdr->nlmsg_type;
return 0;
}
int sd_rtnl_message_link_get_ifindex(sd_rtnl_message *m, int *ifindex) {
struct ifinfomsg *ifi;
assert_return(m, -EINVAL);
assert_return(m->hdr, -EINVAL);
assert_return(rtnl_message_type_is_link(m->hdr->nlmsg_type), -EINVAL);
assert_return(ifindex, -EINVAL);
ifi = NLMSG_DATA(m->hdr);
*ifindex = ifi->ifi_index;
return 0;
}
int sd_rtnl_message_link_get_flags(sd_rtnl_message *m, unsigned *flags) {
struct ifinfomsg *ifi;
assert_return(m, -EINVAL);
assert_return(m->hdr, -EINVAL);
assert_return(rtnl_message_type_is_link(m->hdr->nlmsg_type), -EINVAL);
assert_return(flags, -EINVAL);
ifi = NLMSG_DATA(m->hdr);
*flags = ifi->ifi_flags;
return 0;
}
/* If successful the updated message will be correctly aligned, if
unsuccessful the old message is untouched. */
static int add_rtattr(sd_rtnl_message *m, unsigned short type, const void *data, size_t data_length) {
uint32_t rta_length, message_length;
struct nlmsghdr *new_hdr;
struct rtattr *rta;
char *padding;
unsigned i;
assert(m);
assert(m->hdr);
assert(!m->sealed);
assert(NLMSG_ALIGN(m->hdr->nlmsg_len) == m->hdr->nlmsg_len);
assert(!data || data_length > 0);
assert(data || m->n_containers < RTNL_CONTAINER_DEPTH);
/* get the size of the new rta attribute (with padding at the end) */
rta_length = RTA_LENGTH(data_length);
/* get the new message size (with padding at the end) */
message_length = m->hdr->nlmsg_len + RTA_ALIGN(rta_length);
/* realloc to fit the new attribute */
new_hdr = realloc(m->hdr, message_length);
if (!new_hdr)
return -ENOMEM;
m->hdr = new_hdr;
/* get pointer to the attribute we are about to add */
rta = (struct rtattr *) ((uint8_t *) m->hdr + m->hdr->nlmsg_len);
/* if we are inside containers, extend them */
for (i = 0; i < m->n_containers; i++)
GET_CONTAINER(m, i)->rta_len += message_length - m->hdr->nlmsg_len;
/* fill in the attribute */
rta->rta_type = type;
rta->rta_len = rta_length;
if (!data) {
/* this is the start of a new container */
m->container_offsets[m->n_containers ++] = m->hdr->nlmsg_len;
} else {
/* we don't deal with the case where the user lies about the type
* and gives us too little data (so don't do that)
*/
padding = mempcpy(RTA_DATA(rta), data, data_length);
/* make sure also the padding at the end of the message is initialized */
memzero(padding,
(uint8_t *) m->hdr + message_length - (uint8_t *) padding);
}
/* update message size */
m->hdr->nlmsg_len = message_length;
return 0;
}
int sd_rtnl_message_append_string(sd_rtnl_message *m, unsigned short type, const char *data) {
uint16_t rtm_type;
int r;
assert_return(m, -EINVAL);
assert_return(!m->sealed, -EPERM);
assert_return(data, -EINVAL);
r = sd_rtnl_message_get_type(m, &rtm_type);
if (r < 0)
return r;
/* check that the type is correct */
switch (rtm_type) {
case RTM_NEWLINK:
case RTM_SETLINK:
case RTM_GETLINK:
case RTM_DELLINK:
if (m->n_containers == 1) {
if (GET_CONTAINER(m, 0)->rta_type != IFLA_LINKINFO ||
type != IFLA_INFO_KIND)
return -ENOTSUP;
} else {
switch (type) {
case IFLA_IFNAME:
case IFLA_IFALIAS:
case IFLA_QDISC:
break;
default:
return -ENOTSUP;
}
}
break;
case RTM_NEWADDR:
case RTM_GETADDR:
case RTM_DELADDR:
if (type != IFA_LABEL)
return -ENOTSUP;
break;
default:
return -ENOTSUP;
}
r = add_rtattr(m, type, data, strlen(data) + 1);
if (r < 0)
return r;
return 0;
}
int sd_rtnl_message_append_u8(sd_rtnl_message *m, unsigned short type, uint8_t data) {
uint16_t rtm_type;
int r;
assert_return(m, -EINVAL);
assert_return(!m->sealed, -EPERM);
r = sd_rtnl_message_get_type(m, &rtm_type);
if (r < 0)
return r;
switch (rtm_type) {
case RTM_NEWLINK:
case RTM_SETLINK:
case RTM_GETLINK:
case RTM_DELLINK:
switch (type) {
case IFLA_CARRIER:
case IFLA_OPERSTATE:
case IFLA_LINKMODE:
break;
default:
return -ENOTSUP;
}
break;
default:
return -ENOTSUP;
}
r = add_rtattr(m, type, &data, sizeof(uint8_t));
if (r < 0)
return r;
return 0;
}
int sd_rtnl_message_append_u16(sd_rtnl_message *m, unsigned short type, uint16_t data) {
uint16_t rtm_type;
int r;
assert_return(m, -EINVAL);
assert_return(!m->sealed, -EPERM);
r = sd_rtnl_message_get_type(m, &rtm_type);
if (r < 0)
return r;
/* check that the type is correct */
switch (rtm_type) {
case RTM_NEWLINK:
case RTM_SETLINK:
case RTM_GETLINK:
case RTM_DELLINK:
if (m->n_containers == 2 &&
GET_CONTAINER(m, 0)->rta_type == IFLA_LINKINFO &&
GET_CONTAINER(m, 1)->rta_type == IFLA_INFO_DATA &&
type == IFLA_VLAN_ID)
break;
else
return -ENOTSUP;
break;
default:
return -ENOTSUP;
}
r = add_rtattr(m, type, &data, sizeof(uint16_t));
if (r < 0)
return r;
return 0;
}
int sd_rtnl_message_append_u32(sd_rtnl_message *m, unsigned short type, uint32_t data) {
uint16_t rtm_type;
int r;
assert_return(m, -EINVAL);
assert_return(!m->sealed, -EPERM);
r = sd_rtnl_message_get_type(m, &rtm_type);
if (r < 0)
return r;
/* check that the type is correct */
switch (rtm_type) {
case RTM_NEWLINK:
case RTM_SETLINK:
case RTM_GETLINK:
case RTM_DELLINK:
switch (type) {
case IFLA_MASTER:
case IFLA_MTU:
case IFLA_LINK:
case IFLA_GROUP:
case IFLA_TXQLEN:
case IFLA_WEIGHT:
case IFLA_NET_NS_FD:
case IFLA_NET_NS_PID:
case IFLA_PROMISCUITY:
case IFLA_NUM_TX_QUEUES:
case IFLA_NUM_RX_QUEUES:
break;
default:
return -ENOTSUP;
}
break;
case RTM_NEWROUTE:
case RTM_GETROUTE:
case RTM_DELROUTE:
switch (type) {
case RTA_TABLE:
case RTA_PRIORITY:
case RTA_IIF:
case RTA_OIF:
case RTA_MARK:
break;
default:
return -ENOTSUP;
}
break;
default:
return -ENOTSUP;
}
r = add_rtattr(m, type, &data, sizeof(uint32_t));
if (r < 0)
return r;
return 0;
}
int sd_rtnl_message_append_in_addr(sd_rtnl_message *m, unsigned short type, const struct in_addr *data) {
struct ifaddrmsg *ifa;
struct rtmsg *rtm;
uint16_t rtm_type;
int r;
assert_return(m, -EINVAL);
assert_return(!m->sealed, -EPERM);
assert_return(data, -EINVAL);
r = sd_rtnl_message_get_type(m, &rtm_type);
if (r < 0)
return r;
/* check that the type is correct */
switch (rtm_type) {
case RTM_NEWADDR:
case RTM_GETADDR:
case RTM_DELADDR:
switch (type) {
case IFA_ADDRESS:
case IFA_LOCAL:
case IFA_BROADCAST:
case IFA_ANYCAST:
ifa = NLMSG_DATA(m->hdr);
if (ifa->ifa_family != AF_INET)
return -EINVAL;
break;
default:
return -ENOTSUP;
}
break;
case RTM_NEWROUTE:
case RTM_GETROUTE:
case RTM_DELROUTE:
switch (type) {
case RTA_DST:
case RTA_SRC:
case RTA_GATEWAY:
rtm = NLMSG_DATA(m->hdr);
if (rtm->rtm_family != AF_INET)
return -EINVAL;
break;
default:
return -ENOTSUP;
}
break;
default:
return -ENOTSUP;
}
r = add_rtattr(m, type, data, sizeof(struct in_addr));
if (r < 0)
return r;
return 0;
}
int sd_rtnl_message_append_in6_addr(sd_rtnl_message *m, unsigned short type, const struct in6_addr *data) {
struct ifaddrmsg *ifa;
struct rtmsg *rtm;
uint16_t rtm_type;
int r;
assert_return(m, -EINVAL);
assert_return(!m->sealed, -EPERM);
assert_return(data, -EINVAL);
r = sd_rtnl_message_get_type(m, &rtm_type);
if (r < 0)
return r;
/* check that the type is correct */
switch (rtm_type) {
case RTM_NEWADDR:
case RTM_GETADDR:
case RTM_DELADDR:
switch (type) {
case IFA_ADDRESS:
case IFA_LOCAL:
case IFA_BROADCAST:
case IFA_ANYCAST:
ifa = NLMSG_DATA(m->hdr);
if (ifa->ifa_family != AF_INET6)
return -EINVAL;
break;
default:
return -ENOTSUP;
}
break;
case RTM_NEWROUTE:
case RTM_GETROUTE:
case RTM_DELROUTE:
switch (type) {
case RTA_DST:
case RTA_SRC:
case RTA_GATEWAY:
rtm = NLMSG_DATA(m->hdr);
if (rtm->rtm_family != AF_INET6)
return -EINVAL;
break;
default:
return -ENOTSUP;
}
default:
return -ENOTSUP;
}
r = add_rtattr(m, type, data, sizeof(struct in6_addr));
if (r < 0)
return r;
return 0;
}
int sd_rtnl_message_append_ether_addr(sd_rtnl_message *m, unsigned short type, const struct ether_addr *data) {
uint16_t rtm_type;
int r;
assert_return(m, -EINVAL);
assert_return(!m->sealed, -EPERM);
assert_return(data, -EINVAL);
sd_rtnl_message_get_type(m, &rtm_type);
switch (rtm_type) {
case RTM_NEWLINK:
case RTM_SETLINK:
case RTM_DELLINK:
case RTM_GETLINK:
switch (type) {
case IFLA_ADDRESS:
case IFLA_BROADCAST:
break;
default:
return -ENOTSUP;
}
break;
default:
return -ENOTSUP;
}
r = add_rtattr(m, type, data, ETH_ALEN);
if (r < 0)
return r;
return 0;
}
int sd_rtnl_message_open_container(sd_rtnl_message *m, unsigned short type) {
uint16_t rtm_type;
assert_return(m, -EINVAL);
assert_return(!m->sealed, -EPERM);
sd_rtnl_message_get_type(m, &rtm_type);
if (rtnl_message_type_is_link(rtm_type)) {
if ((type == IFLA_LINKINFO && m->n_containers == 0) ||
(type == IFLA_INFO_DATA && m->n_containers == 1 &&
GET_CONTAINER(m, 0)->rta_type == IFLA_LINKINFO))
return add_rtattr(m, type, NULL, 0);
else
return -ENOTSUP;
} else
return -ENOTSUP;
return 0;
}
int sd_rtnl_message_close_container(sd_rtnl_message *m) {
assert_return(m, -EINVAL);
assert_return(!m->sealed, -EPERM);
assert_return(m->n_containers > 0, -EINVAL);
m->n_containers --;
return 0;
}
int sd_rtnl_message_read(sd_rtnl_message *m, unsigned short *type, void **data) {
size_t remaining_size;
uint16_t rtm_type;
int r;
assert_return(m, -EINVAL);
assert_return(m->sealed, -EPERM);
assert_return(m->next_rta_offset, -EINVAL);
assert_return(type, -EINVAL);
assert_return(data, -EINVAL);
/* only read until the end of the current container */
if (m->n_containers)
remaining_size = GET_CONTAINER(m, m->n_containers - 1)->rta_len -
(m->next_rta_offset -
m->container_offsets[m->n_containers - 1]);
else
remaining_size = m->hdr->nlmsg_len - m->next_rta_offset;
if (!RTA_OK(NEXT_RTA(m), remaining_size))
return 0;
/* if we read a container, enter it and return its type */
r = sd_rtnl_message_get_type(m, &rtm_type);
if (r < 0)
return r;
*type = NEXT_RTA(m)->rta_type;
if (rtnl_message_type_is_link(rtm_type) &&
((m->n_containers == 0 &&
NEXT_RTA(m)->rta_type == IFLA_LINKINFO) ||
(m->n_containers == 1 &&
GET_CONTAINER(m, 0)->rta_type == IFLA_LINKINFO &&
NEXT_RTA(m)->rta_type == IFLA_INFO_DATA))) {
*data = NULL;
PUSH_CONTAINER(m, NEXT_RTA(m));
UPDATE_RTA(m, RTA_DATA(NEXT_RTA(m)));
} else {
*data = RTA_DATA(NEXT_RTA(m));
UPDATE_RTA(m, RTA_NEXT(NEXT_RTA(m), remaining_size));
}
return 1;
}
int sd_rtnl_message_exit_container(sd_rtnl_message *m) {
assert_return(m, -EINVAL);
assert_return(m->sealed, -EINVAL);
assert_return(m->n_containers > 0, -EINVAL);
m->n_containers --;
return 0;
}
uint32_t rtnl_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 rtnl_message_seal(sd_rtnl *nl, sd_rtnl_message *m) {
int r;
assert(m);
assert(m->hdr);
if (m->sealed)
return -EPERM;
if (nl)
m->hdr->nlmsg_seq = nl->serial++;
m->sealed = true;
r = sd_rtnl_message_rewind(m);
if (r < 0)
return r;
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;
/* don't allow sealing/appending to received messages */
m->sealed = true;
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) {
struct ifinfomsg *ifi;
struct ifaddrmsg *ifa;
struct rtmsg *rtm;
/* 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;
else {
ifi = NLMSG_DATA(m->hdr);
UPDATE_RTA(m, IFLA_RTA(ifi));
}
break;
case RTM_NEWADDR:
case RTM_DELADDR:
case RTM_GETADDR:
if (m->hdr->nlmsg_len < NLMSG_LENGTH(sizeof(struct ifaddrmsg)))
k = -EIO;
else {
ifa = NLMSG_DATA(m->hdr);
UPDATE_RTA(m, IFA_RTA(ifa));
}
break;
case RTM_NEWROUTE:
case RTM_DELROUTE:
case RTM_GETROUTE:
if (m->hdr->nlmsg_len < NLMSG_LENGTH(sizeof(struct rtmsg)))
k = -EIO;
else {
rtm = NLMSG_DATA(m->hdr);
UPDATE_RTA(m, RTM_RTA(rtm));
}
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;
}
int sd_rtnl_message_rewind(sd_rtnl_message *m) {
struct ifinfomsg *ifi;
struct ifaddrmsg *ifa;
struct rtmsg *rtm;
assert_return(m, -EINVAL);
assert_return(m->sealed, -EPERM);
assert_return(m->hdr, -EINVAL);
switch(m->hdr->nlmsg_type) {
case RTM_NEWLINK:
case RTM_SETLINK:
case RTM_GETLINK:
case RTM_DELLINK:
ifi = NLMSG_DATA(m->hdr);
UPDATE_RTA(m, IFLA_RTA(ifi));
break;
case RTM_NEWADDR:
case RTM_GETADDR:
case RTM_DELADDR:
ifa = NLMSG_DATA(m->hdr);
UPDATE_RTA(m, IFA_RTA(ifa));
break;
case RTM_NEWROUTE:
case RTM_GETROUTE:
case RTM_DELROUTE:
rtm = NLMSG_DATA(m->hdr);
UPDATE_RTA(m, RTM_RTA(rtm));
break;
default:
return -ENOTSUP;
}
m->n_containers = 0;
return 0;
}