emo/ndhc
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
f7de4a14fd
ndhc/ndhc/ifset.c
Nicholas J. Kain f7de4a14fd Use NLMSG_DATA() instead of nlmsg_get_data().
2014-03-17 20:26:37 -04:00

654 lines
21 KiB
C
Raw Blame History

/* ifset.c - Linux-specific net interface settings include
*
* Copyright (c) 2004-2014 Nicholas J. Kain <njkain at gmail dot com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#define __USE_GNU 1
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/route.h>
#include <net/if.h>
#include <netpacket/packet.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <pwd.h>
#include <grp.h>
#include <errno.h>
#include "ifset.h"
#include "ifchd.h"
#include "ndhc.h"
#include "log.h"
#include "ifch_proto.h"
#include "strl.h"
#include "nl.h"
static uint32_t ifset_nl_seq = 1;
// 32-bit position values are relatively prime to 37, so the residue mod37
// gives a unique mapping for each value. Gives correct result for v=0.
static int trailz(uint32_t v)
{
static const int bpm37[] = {
32, 0, 1, 26, 2, 23, 27, 0, 3, 16, 24, 30, 28, 11, 0, 13, 4, 7, 17,
0, 25, 22, 31, 15, 29, 10, 12, 6, 0, 21, 14, 9, 5, 20, 8, 19, 18
};
return bpm37[(-v & v) % 37];
}
// sn must be in network order
static inline int subnet4_to_prefixlen(uint32_t sn)
{
return 32 - trailz(ntohl(sn));
}
struct ipbcpfx {
int fd;
uint32_t ipaddr;
uint32_t bcast;
uint8_t prefixlen;
bool already_ok;
};
static ssize_t rtnl_do_send(int fd, uint8_t *sbuf, size_t slen,
const char *fnname)
{
uint8_t response[NLMSG_ALIGN(sizeof(struct nlmsghdr)) + 64];
struct sockaddr_nl nl_addr;
ssize_t r;
memset(&nl_addr, 0, sizeof nl_addr);
nl_addr.nl_family = AF_NETLINK;
retry_sendto:
r = sendto(fd, sbuf, slen, 0, (struct sockaddr *)&nl_addr,
sizeof nl_addr);
if (r < 0) {
if (errno == EINTR)
goto retry_sendto;
else {
log_line("%s: (%s) netlink sendto failed: %s",
client_config.interface, fnname, strerror(errno));
return -1;
}
}
struct iovec iov = {
.iov_base = response,
.iov_len = sizeof response,
};
struct msghdr msg = {
.msg_name = &nl_addr,
.msg_namelen = sizeof nl_addr,
.msg_iov = &iov,
.msg_iovlen = 1,
};
retry_recv:
r = recvmsg(fd, &msg, 0);
if (r < 0) {
if (errno == EINTR)
goto retry_recv;
else {
log_line("%s: (%s) netlink recvmsg failed: %s",
client_config.interface, fnname, strerror(errno));
return -1;
}
}
if (msg.msg_flags & MSG_TRUNC) {
log_error("%s: (%s) Buffer not long enough for message.",
client_config.interface, fnname);
return -1;
}
if ((size_t)r < sizeof(struct nlmsghdr)) {
log_line("%s: (%s) netlink recvmsg returned a headerless response",
client_config.interface, fnname);
return -1;
}
const struct nlmsghdr *nlh = (const struct nlmsghdr *)response;
if (nlh->nlmsg_type == NLMSG_ERROR) {
if (nlmsg_get_error(nlh) == 0)
return 0;
else {
log_line("%s: (%s) netlink sendto returned NLMSG_ERROR: %s",
client_config.interface, fnname,
strerror(nlmsg_get_error(nlh)));
return -1;
}
}
if (nlh->nlmsg_type == NLMSG_DONE)
return -2;
log_line("%s: (%s) netlink sendto returned an error.",
client_config.interface, __func__);
return -1;
}
static ssize_t rtnl_if_flags_send(int fd, int type, int ifi_flags)
{
uint8_t request[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
NLMSG_ALIGN(sizeof(struct ifinfomsg))];
struct nlmsghdr *header;
struct ifinfomsg *ifinfomsg;
memset(&request, 0, sizeof request);
header = (struct nlmsghdr *)request;
header->nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
header->nlmsg_type = type;
header->nlmsg_flags = NLM_F_ACK | NLM_F_REQUEST;
header->nlmsg_seq = ifset_nl_seq++;
ifinfomsg = NLMSG_DATA(header);
ifinfomsg->ifi_flags = ifi_flags;
ifinfomsg->ifi_index = client_config.ifindex;
ifinfomsg->ifi_change = 0xffffffff;
return rtnl_do_send(fd, request, header->nlmsg_len, __func__);
}
static ssize_t rtnl_addr_broadcast_send(int fd, int type, int ifa_flags,
int ifa_scope, uint32_t *ipaddr,
uint32_t *bcast, uint8_t prefixlen)
{
uint8_t request[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
2 * RTA_LENGTH(sizeof(struct in6_addr))];
struct nlmsghdr *header;
struct ifaddrmsg *ifaddrmsg;
if (!ipaddr && !bcast) {
log_warning("%s: (%s) no ipaddr or bcast!",
client_config.interface, __func__);
return -1;
}
memset(&request, 0, sizeof request);
header = (struct nlmsghdr *)request;
header->nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
header->nlmsg_type = type;
header->nlmsg_flags = NLM_F_REPLACE | NLM_F_ACK | NLM_F_REQUEST;
header->nlmsg_seq = ifset_nl_seq++;
ifaddrmsg = NLMSG_DATA(header);
ifaddrmsg->ifa_family = AF_INET;
ifaddrmsg->ifa_prefixlen = prefixlen;
ifaddrmsg->ifa_flags = ifa_flags;
ifaddrmsg->ifa_scope = ifa_scope;
ifaddrmsg->ifa_index = client_config.ifindex;
if (ipaddr) {
if (nl_add_rtattr(header, sizeof request, IFA_LOCAL,
ipaddr, sizeof *ipaddr) < 0) {
log_line("%s: (%s) couldn't add IFA_LOCAL to nlmsg",
client_config.interface, __func__);
return -1;
}
}
if (bcast) {
if (nl_add_rtattr(header, sizeof request, IFA_BROADCAST,
bcast, sizeof *bcast) < 0) {
log_line("%s: (%s) couldn't add IFA_BROADCAST to nlmsg",
client_config.interface, __func__);
return -1;
}
}
return rtnl_do_send(fd, request, header->nlmsg_len, __func__);
}
static ssize_t rtnl_set_default_gw_v4(int fd, uint32_t gw4, int metric)
{
uint8_t request[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
NLMSG_ALIGN(sizeof(struct rtmsg)) +
3 * RTA_LENGTH(sizeof(struct in6_addr)) +
RTA_LENGTH(sizeof(int))];
struct nlmsghdr *header;
struct rtmsg *rtmsg;
memset(&request, 0, sizeof request);
header = (struct nlmsghdr *)request;
header->nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
header->nlmsg_type = RTM_NEWROUTE;
header->nlmsg_flags = NLM_F_CREATE | NLM_F_REPLACE | NLM_F_ACK
| NLM_F_REQUEST;
header->nlmsg_seq = ifset_nl_seq++;
rtmsg = NLMSG_DATA(header);
rtmsg->rtm_family = AF_INET;
rtmsg->rtm_protocol = RTPROT_DHCP;
rtmsg->rtm_scope = RT_SCOPE_UNIVERSE;
rtmsg->rtm_type = RTN_UNICAST;
uint32_t dstaddr4 = 0;
if (nl_add_rtattr(header, sizeof request, RTA_DST,
&dstaddr4, sizeof dstaddr4) < 0) {
log_line("%s: (%s) couldn't add RTA_DST to nlmsg",
client_config.interface, __func__);
return -1;
}
if (nl_add_rtattr(header, sizeof request, RTA_OIF,
&client_config.ifindex,
sizeof client_config.ifindex) < 0) {
log_line("%s: (%s) couldn't add RTA_OIF to nlmsg",
client_config.interface, __func__);
return -1;
}
if (nl_add_rtattr(header, sizeof request, RTA_GATEWAY,
&gw4, sizeof gw4) < 0) {
log_line("%s: (%s) couldn't add RTA_GATEWAY to nlmsg",
client_config.interface, __func__);
return -1;
}
if (metric > 0) {
if (nl_add_rtattr(header, sizeof request, RTA_PRIORITY,
&metric, sizeof metric) < 0) {
log_line("%s: (%s) couldn't add RTA_PRIORITY to nlmsg",
client_config.interface, __func__);
return -1;
}
}
return rtnl_do_send(fd, request, header->nlmsg_len, __func__);
}
struct link_flag_data {
int fd;
uint32_t flags;
bool got_flags;
};
static void link_flags_get_do(const struct nlmsghdr *nlh, void *data)
{
struct ifinfomsg *ifm = NLMSG_DATA(nlh);
struct link_flag_data *ifd = data;
switch(nlh->nlmsg_type) {
case RTM_NEWLINK:
if (ifm->ifi_index != client_config.ifindex)
break;
ifd->flags = ifm->ifi_flags;
ifd->got_flags = true;
break;
case RTM_DELLINK:
log_line("%s: got RTM_DELLINK", __func__);
break;
default:
log_line("%s: got %u", __func__, nlh->nlmsg_type);
break;
}
}
static int link_flags_get(int fd, uint32_t *flags)
{
char nlbuf[8192];
struct link_flag_data ipx = { .fd = fd, .flags = 0, .got_flags = false };
ssize_t ret;
uint32_t seq = ifset_nl_seq++;
if (nl_sendgetlink(fd, seq, client_config.ifindex) < 0)
return -1;
do {
ret = nl_recv_buf(fd, nlbuf, sizeof nlbuf);
if (ret == -1)
return -2;
if (nl_foreach_nlmsg(nlbuf, ret, seq, 0, link_flags_get_do,
&ipx) == -1)
return -3;
} while (ret > 0);
if (ipx.got_flags) {
*flags = ipx.flags;
return 0;
}
return -4;
}
static int link_set_flags(int fd, uint32_t flags)
{
uint32_t oldflags;
int r = link_flags_get(fd, &oldflags);
if (r < 0) {
log_line("%s: (%s) failed to get old link flags: %u",
client_config.interface, __func__, r);
return -1;
}
if ((oldflags & flags) == flags)
return 1;
return (int)rtnl_if_flags_send(fd, RTM_SETLINK, flags | oldflags);
}
#if 0
static int link_unset_flags(int fd, uint32_t flags)
{
uint32_t oldflags;
int r = link_flags_get(fd, &oldflags);
if (r < 0) {
log_line("%s: (%s) failed to get old link flags: %u",
client_config.interface, __func__, r);
return -1;
}
if ((oldflags & flags) == 0)
return 1;
return (int)rtnl_if_flags_send(fd, RTM_SETLINK, oldflags & ~flags);
}
#endif
static void ipbcpfx_clear_others_do(const struct nlmsghdr *nlh, void *data)
{
struct rtattr *tb[IFA_MAX] = {0};
struct ifaddrmsg *ifm = NLMSG_DATA(nlh);
struct ipbcpfx *ipx = data;
int r;
nl_rtattr_parse(nlh, sizeof *ifm, rtattr_assign, tb);
switch(nlh->nlmsg_type) {
case RTM_NEWADDR:
if (ifm->ifa_index != (unsigned)client_config.ifindex)
return;
if (ifm->ifa_family != AF_INET)
return;
if (!(ifm->ifa_flags & IFA_F_PERMANENT))
goto erase;
if (ifm->ifa_scope != RT_SCOPE_UNIVERSE)
goto erase;
if (ifm->ifa_prefixlen != ipx->prefixlen)
goto erase;
if (!tb[IFA_ADDRESS])
goto erase;
if (memcmp(rtattr_get_data(tb[IFA_ADDRESS]), &ipx->ipaddr,
sizeof ipx->ipaddr))
goto erase;
if (!tb[IFA_BROADCAST])
goto erase;
if (memcmp(rtattr_get_data(tb[IFA_BROADCAST]), &ipx->bcast,
sizeof ipx->bcast))
goto erase;
break;
default:
return;
}
// We already have the proper IP+broadcast+prefix.
ipx->already_ok = true;
return;
erase:
r = rtnl_addr_broadcast_send(ipx->fd, RTM_DELADDR, ifm->ifa_flags,
ifm->ifa_scope,
tb[IFA_ADDRESS] ? rtattr_get_data(tb[IFA_ADDRESS]) : NULL,
tb[IFA_BROADCAST] ? rtattr_get_data(tb[IFA_BROADCAST]) : NULL,
ifm->ifa_prefixlen);
if (r < 0 && r != -2) {
log_warning("%s: (%s) Failed to delete IP and broadcast addresses.",
client_config.interface, __func__);
}
return;
}
static int ipbcpfx_clear_others(int fd, uint32_t ipaddr, uint32_t bcast,
uint8_t prefixlen)
{
char nlbuf[8192];
struct ipbcpfx ipx = { .fd = fd, .ipaddr = ipaddr, .bcast = bcast,
.prefixlen = prefixlen, .already_ok = false };
ssize_t ret;
uint32_t seq = ifset_nl_seq++;
if (nl_sendgetaddr(fd, seq, client_config.ifindex) < 0)
return -1;
do {
ret = nl_recv_buf(fd, nlbuf, sizeof nlbuf);
if (ret == -1)
return -2;
if (nl_foreach_nlmsg(nlbuf, ret, seq, 0,
ipbcpfx_clear_others_do, &ipx) == -1)
return -3;
} while (ret > 0);
return ipx.already_ok ? 1 : 0;
}
static ssize_t rtnl_if_mtu_set(int fd, unsigned int mtu)
{
uint8_t request[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
NLMSG_ALIGN(sizeof(struct ifinfomsg)) +
RTA_LENGTH(sizeof(unsigned int))];
struct nlmsghdr *header;
struct ifinfomsg *ifinfomsg;
uint32_t oldflags;
int r = link_flags_get(fd, &oldflags);
if (r < 0) {
log_line("%s: (%s) failed to get old link flags: %u",
client_config.interface, __func__, r);
return -1;
}
memset(&request, 0, sizeof request);
header = (struct nlmsghdr *)request;
header->nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
header->nlmsg_type = RTM_SETLINK;
header->nlmsg_flags = NLM_F_ACK | NLM_F_REQUEST;
header->nlmsg_seq = ifset_nl_seq++;
ifinfomsg = NLMSG_DATA(header);
ifinfomsg->ifi_flags = oldflags;
ifinfomsg->ifi_index = client_config.ifindex;
ifinfomsg->ifi_change = 0xffffffff;
if (nl_add_rtattr(header, sizeof request, IFLA_MTU,
&mtu, sizeof mtu) < 0) {
log_line("%s: (%s) couldn't add IFLA_MTU to nlmsg",
client_config.interface, __func__);
return -1;
}
return rtnl_do_send(fd, request, header->nlmsg_len, __func__);
}
int perform_ifup(void)
{
int fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
if (fd < 0) {
log_line("%s: (%s) netlink socket open failed: %s",
client_config.interface, __func__, strerror(errno));
return fd;
}
int r = link_set_flags(fd, IFF_UP);
if (r < 0)
log_line("%s: (%s) Failed to set link to be up.",
client_config.interface, __func__);
close(fd);
return r;
}
// str_bcast is optional.
void perform_ip_subnet_bcast(const char *str_ipaddr,
const char *str_subnet, const char *str_bcast)
{
struct in_addr ipaddr, subnet, bcast;
int fd, r;
uint8_t prefixlen;
if (!str_ipaddr) {
log_line("%s: (%s) interface ip address is NULL",
client_config.interface, __func__);
return;
}
if (!str_subnet) {
log_line("%s: (%s) interface subnet address is NULL",
client_config.interface, __func__);
return;
}
if (inet_pton(AF_INET, str_ipaddr, &ipaddr) <= 0) {
log_line("%s: (%s) bad interface ip address: '%s'",
client_config.interface, __func__, str_ipaddr);
return;
}
if (inet_pton(AF_INET, str_subnet, &subnet) <= 0) {
log_line("%s: (%s) bad interface subnet address: '%s'",
client_config.interface, __func__, str_subnet);
return;
}
prefixlen = subnet4_to_prefixlen(subnet.s_addr);
if (str_bcast) {
if (inet_pton(AF_INET, str_bcast, &bcast) <= 0) {
log_line("%s: (%s) bad interface broadcast address: '%s'",
client_config.interface, __func__, str_bcast);
return;
}
} else {
// Generate the standard broadcast address if unspecified.
bcast.s_addr = ipaddr.s_addr | htonl(0xfffffffflu >> prefixlen);
}
fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
if (fd < 0) {
log_line("%s: (%s) netlink socket open failed: %s",
client_config.interface, __func__, strerror(errno));
return;
}
r = ipbcpfx_clear_others(fd, ipaddr.s_addr, bcast.s_addr, prefixlen);
if (r < 0 && r > -3) {
if (r == -1)
log_line("%s: (%s) error requesting link ip address list",
client_config.interface, __func__);
else if (r == -2)
log_line("%s: (%s) error receiving link ip address list",
client_config.interface, __func__);
close(fd);
return;
}
if (r < 1) {
r = rtnl_addr_broadcast_send(fd, RTM_NEWADDR, IFA_F_PERMANENT,
RT_SCOPE_UNIVERSE, &ipaddr.s_addr, &bcast.s_addr,
prefixlen);
if (r < 0) {
close(fd);
return;
}
log_line("Interface IP set to: '%s'", str_ipaddr);
log_line("Interface subnet set to: '%s'", str_subnet);
if (str_bcast)
log_line("Broadcast address set to: '%s'", str_bcast);
} else
log_line("Interface IP, subnet, and broadcast were already OK.");
if (link_set_flags(fd, IFF_UP | IFF_RUNNING) < 0)
log_line("%s: (%s) Failed to set link to be up and running.",
client_config.interface, __func__);
close(fd);
}
void perform_router(const char *str_router, size_t len)
{
if (!str_router)
return;
if (len < 7)
return;
struct in_addr router;
if (inet_pton(AF_INET, str_router, &router) <= 0) {
log_line("%s: (%s) bad router ip address: '%s'",
client_config.interface, __func__, str_router);
return;
}
int fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
if (fd < 0) {
log_line("%s: (%s) netlink socket open failed: %s",
client_config.interface, __func__, strerror(errno));
return;
}
if (rtnl_set_default_gw_v4(fd, router.s_addr, 0) < 0)
log_line("%s: (%s) failed to set route: %s",
client_config.interface, __func__, strerror(errno));
else
log_line("Gateway router set to: '%s'", str_router);
close(fd);
}
void perform_mtu(const char *str, size_t len)
{
if (!str)
return;
if (len < 2)
return;
char *estr;
long tmtu = strtol(str, &estr, 10);
if (estr == str) {
log_line("%s: (%s) provided mtu arg isn't a valid number",
client_config.interface, __func__);
return;
}
if ((tmtu == LONG_MAX || tmtu == LONG_MIN) && errno == ERANGE) {
log_line("%s: (%s) provided mtu arg would overflow a long",
client_config.interface, __func__);
return;
}
if (tmtu > INT_MAX) {
log_line("%s: (%s) provided mtu arg would overflow int",
client_config.interface, __func__);
return;
}
// 68 bytes for IPv4. 1280 bytes for IPv6.
if (tmtu < 68) {
log_line("%s: (%s) provided mtu arg (%ul) less than minimum MTU (68)",
client_config.interface, __func__, tmtu);
return;
}
unsigned int mtu = (unsigned int)tmtu;
int fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
if (fd < 0) {
log_line("%s: (%s) netlink socket open failed: %s",
client_config.interface, __func__, strerror(errno));
return;
}
if (rtnl_if_mtu_set(fd, mtu) < 0)
log_line("%s: (%s) failed to set MTU [%d]",
client_config.interface, __func__, mtu);
else
log_line("MTU set to: '%s'", str);
close(fd);
}
Reference in New Issue View Git Blame Copy Permalink