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src/sbin/dhcpleased/frontend.c

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/* $OpenBSD: frontend.c,v 1.33 2024/01/26 21:14:08 jan Exp $ */
/*
* Copyright (c) 2017, 2021 Florian Obser <florian@openbsd.org>
* Copyright (c) 2005 Claudio Jeker <claudio@openbsd.org>
* Copyright (c) 2004 Esben Norby <norby@openbsd.org>
* Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <sys/uio.h>
#include <net/bpf.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <arpa/inet.h>
#include <errno.h>
#include <event.h>
#include <ifaddrs.h>
#include <imsg.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "bpf.h"
#include "log.h"
#include "dhcpleased.h"
#include "frontend.h"
#include "control.h"
#include "checksum.h"
#define ROUTE_SOCKET_BUF_SIZE 16384
#define BOOTP_MIN_LEN 300 /* fixed bootp packet adds up to 300 */
struct bpf_ev {
struct event ev;
uint8_t buf[BPFLEN];
};
struct iface {
LIST_ENTRY(iface) entries;
struct bpf_ev bpfev;
struct imsg_ifinfo ifinfo;
int send_discover;
uint32_t xid;
struct in_addr ciaddr;
struct in_addr requested_ip;
struct in_addr server_identifier;
struct in_addr dhcp_server;
int udpsock;
};
__dead void frontend_shutdown(void);
void frontend_sig_handler(int, short, void *);
void update_iface(struct if_msghdr *, struct sockaddr_dl *);
void frontend_startup(void);
void init_ifaces(void);
void route_receive(int, short, void *);
void handle_route_message(struct rt_msghdr *, struct sockaddr **);
void get_rtaddrs(int, struct sockaddr *, struct sockaddr **);
void bpf_receive(int, short, void *);
int get_flags(char *);
int get_xflags(char *);
struct iface *get_iface_by_id(uint32_t);
void remove_iface(uint32_t);
void set_bpfsock(int, uint32_t);
void iface_data_from_imsg(struct iface*, struct imsg_req_dhcp *);
ssize_t build_packet(uint8_t, char *, uint32_t, struct ether_addr *,
struct in_addr *, struct in_addr *, struct in_addr *);
void send_packet(uint8_t, struct iface *);
void bpf_send_packet(struct iface *, uint8_t *, ssize_t);
int udp_send_packet(struct iface *, uint8_t *, ssize_t);
#ifndef SMALL
int iface_conf_cmp(struct iface_conf *, struct iface_conf *);
#endif /* SMALL */
LIST_HEAD(, iface) interfaces;
struct dhcpleased_conf *frontend_conf;
static struct imsgev *iev_main;
static struct imsgev *iev_engine;
struct event ev_route;
int ioctlsock;
uint8_t dhcp_packet[1500];
void
frontend_sig_handler(int sig, short event, void *bula)
{
/*
* Normal signal handler rules don't apply because libevent
* decouples for us.
*/
switch (sig) {
case SIGINT:
case SIGTERM:
frontend_shutdown();
default:
fatalx("unexpected signal");
}
}
void
frontend(int debug, int verbose)
{
struct event ev_sigint, ev_sigterm;
struct passwd *pw;
#ifndef SMALL
frontend_conf = config_new_empty();
#endif /* SMALL */
log_init(debug, LOG_DAEMON);
log_setverbose(verbose);
if ((pw = getpwnam(DHCPLEASED_USER)) == NULL)
fatal("getpwnam");
if (chdir("/") == -1)
fatal("chdir(\"/\")");
if (unveil("/", "") == -1)
fatal("unveil /");
if (unveil(NULL, NULL) == -1)
fatal("unveil");
setproctitle("%s", "frontend");
log_procinit("frontend");
if ((ioctlsock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0)) == -1)
fatal("socket");
if (setgroups(1, &pw->pw_gid) ||
setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
fatal("can't drop privileges");
if (pledge("stdio unix recvfd route", NULL) == -1)
fatal("pledge");
event_init();
/* Setup signal handler. */
signal_set(&ev_sigint, SIGINT, frontend_sig_handler, NULL);
signal_set(&ev_sigterm, SIGTERM, frontend_sig_handler, NULL);
signal_add(&ev_sigint, NULL);
signal_add(&ev_sigterm, NULL);
signal(SIGPIPE, SIG_IGN);
signal(SIGHUP, SIG_IGN);
/* Setup pipe and event handler to the parent process. */
if ((iev_main = malloc(sizeof(struct imsgev))) == NULL)
fatal(NULL);
imsg_init(&iev_main->ibuf, 3);
iev_main->handler = frontend_dispatch_main;
iev_main->events = EV_READ;
event_set(&iev_main->ev, iev_main->ibuf.fd, iev_main->events,
iev_main->handler, iev_main);
event_add(&iev_main->ev, NULL);
LIST_INIT(&interfaces);
event_dispatch();
frontend_shutdown();
}
__dead void
frontend_shutdown(void)
{
/* Close pipes. */
msgbuf_write(&iev_engine->ibuf.w);
msgbuf_clear(&iev_engine->ibuf.w);
close(iev_engine->ibuf.fd);
msgbuf_write(&iev_main->ibuf.w);
msgbuf_clear(&iev_main->ibuf.w);
close(iev_main->ibuf.fd);
#ifndef SMALL
config_clear(frontend_conf);
#endif /* SMALL */
free(iev_engine);
free(iev_main);
log_info("frontend exiting");
exit(0);
}
int
frontend_imsg_compose_main(int type, pid_t pid, void *data,
uint16_t datalen)
{
return (imsg_compose_event(iev_main, type, 0, pid, -1, data,
datalen));
}
int
frontend_imsg_compose_engine(int type, uint32_t peerid, pid_t pid,
void *data, uint16_t datalen)
{
return (imsg_compose_event(iev_engine, type, peerid, pid, -1,
data, datalen));
}
void
frontend_dispatch_main(int fd, short event, void *bula)
{
static struct dhcpleased_conf *nconf;
static struct iface_conf *iface_conf;
struct imsg imsg;
struct imsgev *iev = bula;
struct imsgbuf *ibuf = &iev->ibuf;
struct iface *iface;
ssize_t n;
int shut = 0, bpfsock, if_index, udpsock;
if (event & EV_READ) {
if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
fatal("imsg_read error");
if (n == 0) /* Connection closed. */
shut = 1;
}
if (event & EV_WRITE) {
if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
fatal("msgbuf_write");
if (n == 0) /* Connection closed. */
shut = 1;
}
for (;;) {
if ((n = imsg_get(ibuf, &imsg)) == -1)
fatal("%s: imsg_get error", __func__);
if (n == 0) /* No more messages. */
break;
switch (imsg.hdr.type) {
case IMSG_SOCKET_IPC:
/*
* Setup pipe and event handler to the engine
* process.
*/
if (iev_engine)
fatalx("%s: received unexpected imsg fd "
"to frontend", __func__);
if ((fd = imsg_get_fd(&imsg)) == -1)
fatalx("%s: expected to receive imsg fd to "
"frontend but didn't receive any",
__func__);
iev_engine = malloc(sizeof(struct imsgev));
if (iev_engine == NULL)
fatal(NULL);
imsg_init(&iev_engine->ibuf, fd);
iev_engine->handler = frontend_dispatch_engine;
iev_engine->events = EV_READ;
event_set(&iev_engine->ev, iev_engine->ibuf.fd,
iev_engine->events, iev_engine->handler, iev_engine);
event_add(&iev_engine->ev, NULL);
break;
case IMSG_BPFSOCK:
if ((bpfsock = imsg_get_fd(&imsg)) == -1)
fatalx("%s: expected to receive imsg "
"bpf fd but didn't receive any",
__func__);
if (IMSG_DATA_SIZE(imsg) != sizeof(if_index))
fatalx("%s: IMSG_BPFSOCK wrong length: "
"%lu", __func__, IMSG_DATA_SIZE(imsg));
memcpy(&if_index, imsg.data, sizeof(if_index));
set_bpfsock(bpfsock, if_index);
break;
case IMSG_UDPSOCK:
if ((udpsock = imsg_get_fd(&imsg)) == -1)
fatalx("%s: expected to receive imsg "
"udpsocket fd but didn't receive any",
__func__);
if (IMSG_DATA_SIZE(imsg) != sizeof(if_index))
fatalx("%s: IMSG_UDPSOCK wrong length: "
"%lu", __func__, IMSG_DATA_SIZE(imsg));
memcpy(&if_index, imsg.data, sizeof(if_index));
if ((iface = get_iface_by_id(if_index)) == NULL) {
close(fd);
break;
}
if (iface->udpsock != -1)
fatalx("%s: received unexpected udpsocket",
__func__);
iface->udpsock = udpsock;
break;
case IMSG_CLOSE_UDPSOCK:
if (IMSG_DATA_SIZE(imsg) != sizeof(if_index))
fatalx("%s: IMSG_UDPSOCK wrong length: "
"%lu", __func__, IMSG_DATA_SIZE(imsg));
memcpy(&if_index, imsg.data, sizeof(if_index));
if ((iface = get_iface_by_id(if_index)) != NULL &&
iface->udpsock != -1) {
close(iface->udpsock);
iface->udpsock = -1;
}
break;
case IMSG_ROUTESOCK:
if ((fd = imsg_get_fd(&imsg)) == -1)
fatalx("%s: expected to receive imsg "
"routesocket fd but didn't receive any",
__func__);
event_set(&ev_route, fd, EV_READ | EV_PERSIST,
route_receive, NULL);
break;
case IMSG_STARTUP:
frontend_startup();
break;
#ifndef SMALL
case IMSG_RECONF_CONF:
if (nconf != NULL)
fatalx("%s: IMSG_RECONF_CONF already in "
"progress", __func__);
if ((nconf = malloc(sizeof(struct dhcpleased_conf))) ==
NULL)
fatal(NULL);
SIMPLEQ_INIT(&nconf->iface_list);
break;
case IMSG_RECONF_IFACE:
if (IMSG_DATA_SIZE(imsg) != sizeof(struct
iface_conf))
fatalx("%s: IMSG_RECONF_IFACE wrong length: "
"%lu", __func__, IMSG_DATA_SIZE(imsg));
if ((iface_conf = malloc(sizeof(struct iface_conf)))
== NULL)
fatal(NULL);
memcpy(iface_conf, imsg.data, sizeof(struct
iface_conf));
iface_conf->vc_id = NULL;
iface_conf->vc_id_len = 0;
iface_conf->c_id = NULL;
iface_conf->c_id_len = 0;
iface_conf->h_name = NULL;
SIMPLEQ_INSERT_TAIL(&nconf->iface_list,
iface_conf, entry);
break;
case IMSG_RECONF_VC_ID:
if (iface_conf == NULL)
fatal("IMSG_RECONF_VC_ID without "
"IMSG_RECONF_IFACE");
if (IMSG_DATA_SIZE(imsg) > 255 + 2)
fatalx("%s: IMSG_RECONF_VC_ID wrong length: "
"%lu", __func__, IMSG_DATA_SIZE(imsg));
if ((iface_conf->vc_id = malloc(IMSG_DATA_SIZE(imsg)))
== NULL)
fatal(NULL);
memcpy(iface_conf->vc_id, imsg.data,
IMSG_DATA_SIZE(imsg));
iface_conf->vc_id_len = IMSG_DATA_SIZE(imsg);
break;
case IMSG_RECONF_C_ID:
if (iface_conf == NULL)
fatal("IMSG_RECONF_C_ID without "
"IMSG_RECONF_IFACE");
if (IMSG_DATA_SIZE(imsg) > 255 + 2)
fatalx("%s: IMSG_RECONF_C_ID wrong length: "
"%lu", __func__, IMSG_DATA_SIZE(imsg));
if ((iface_conf->c_id = malloc(IMSG_DATA_SIZE(imsg)))
== NULL)
fatal(NULL);
memcpy(iface_conf->c_id, imsg.data,
IMSG_DATA_SIZE(imsg));
iface_conf->c_id_len = IMSG_DATA_SIZE(imsg);
break;
case IMSG_RECONF_H_NAME:
if (iface_conf == NULL)
fatal("IMSG_RECONF_H_NAME without "
"IMSG_RECONF_IFACE");
if (((char *)imsg.data)[IMSG_DATA_SIZE(imsg) - 1] !=
'\0')
fatalx("Invalid hostname");
if (IMSG_DATA_SIZE(imsg) > 256)
fatalx("Invalid hostname");
if ((iface_conf->h_name = strdup(imsg.data)) == NULL)
fatal(NULL);
break;
case IMSG_RECONF_END: {
int i;
int *ifaces;
char ifnamebuf[IF_NAMESIZE], *if_name;
if (nconf == NULL)
fatalx("%s: IMSG_RECONF_END without "
"IMSG_RECONF_CONF", __func__);
ifaces = changed_ifaces(frontend_conf, nconf);
merge_config(frontend_conf, nconf);
nconf = NULL;
for (i = 0; ifaces[i] != 0; i++) {
if_index = ifaces[i];
if_name = if_indextoname(if_index, ifnamebuf);
log_debug("changed iface: %s[%d]", if_name !=
NULL ? if_name : "<unknown>", if_index);
frontend_imsg_compose_engine(
IMSG_REQUEST_REBOOT, 0, 0, &if_index,
sizeof(if_index));
}
free(ifaces);
break;
}
case IMSG_CONTROLFD:
if ((fd = imsg_get_fd(&imsg)) == -1)
fatalx("%s: expected to receive imsg "
"control fd but didn't receive any",
__func__);
/* Listen on control socket. */
control_listen(fd);
break;
case IMSG_CTL_END:
control_imsg_relay(&imsg);
break;
#endif /* SMALL */
default:
log_debug("%s: error handling imsg %d", __func__,
imsg.hdr.type);
break;
}
imsg_free(&imsg);
}
if (!shut)
imsg_event_add(iev);
else {
/* This pipe is dead. Remove its event handler. */
event_del(&iev->ev);
event_loopexit(NULL);
}
}
void
frontend_dispatch_engine(int fd, short event, void *bula)
{
struct imsgev *iev = bula;
struct imsgbuf *ibuf = &iev->ibuf;
struct imsg imsg;
struct iface *iface;
ssize_t n;
int shut = 0;
if (event & EV_READ) {
if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
fatal("imsg_read error");
if (n == 0) /* Connection closed. */
shut = 1;
}
if (event & EV_WRITE) {
if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
fatal("msgbuf_write");
if (n == 0) /* Connection closed. */
shut = 1;
}
for (;;) {
if ((n = imsg_get(ibuf, &imsg)) == -1)
fatal("%s: imsg_get error", __func__);
if (n == 0) /* No more messages. */
break;
switch (imsg.hdr.type) {
#ifndef SMALL
case IMSG_CTL_END:
case IMSG_CTL_SHOW_INTERFACE_INFO:
control_imsg_relay(&imsg);
break;
#endif /* SMALL */
case IMSG_SEND_DISCOVER: {
struct imsg_req_dhcp imsg_req_dhcp;
if (IMSG_DATA_SIZE(imsg) != sizeof(imsg_req_dhcp))
fatalx("%s: IMSG_SEND_DISCOVER wrong "
"length: %lu", __func__,
IMSG_DATA_SIZE(imsg));
memcpy(&imsg_req_dhcp, imsg.data,
sizeof(imsg_req_dhcp));
iface = get_iface_by_id(imsg_req_dhcp.if_index);
if (iface == NULL)
break;
iface_data_from_imsg(iface, &imsg_req_dhcp);
send_packet(DHCPDISCOVER, iface);
break;
}
case IMSG_SEND_REQUEST: {
struct imsg_req_dhcp imsg_req_dhcp;
if (IMSG_DATA_SIZE(imsg) != sizeof(imsg_req_dhcp))
fatalx("%s: IMSG_SEND_REQUEST wrong "
"length: %lu", __func__,
IMSG_DATA_SIZE(imsg));
memcpy(&imsg_req_dhcp, imsg.data,
sizeof(imsg_req_dhcp));
iface = get_iface_by_id(imsg_req_dhcp.if_index);
if (iface == NULL)
break;
iface_data_from_imsg(iface, &imsg_req_dhcp);
send_packet(DHCPREQUEST, iface);
break;
}
default:
log_debug("%s: error handling imsg %d", __func__,
imsg.hdr.type);
break;
}
imsg_free(&imsg);
}
if (!shut)
imsg_event_add(iev);
else {
/* This pipe is dead. Remove its event handler. */
event_del(&iev->ev);
event_loopexit(NULL);
}
}
int
get_flags(char *if_name)
{
struct ifreq ifr;
strlcpy(ifr.ifr_name, if_name, sizeof(ifr.ifr_name));
if (ioctl(ioctlsock, SIOCGIFFLAGS, (caddr_t)&ifr) == -1) {
log_warn("SIOCGIFFLAGS");
return -1;
}
return ifr.ifr_flags;
}
int
get_xflags(char *if_name)
{
struct ifreq ifr;
strlcpy(ifr.ifr_name, if_name, sizeof(ifr.ifr_name));
if (ioctl(ioctlsock, SIOCGIFXFLAGS, (caddr_t)&ifr) == -1) {
log_warn("SIOCGIFXFLAGS");
return -1;
}
return ifr.ifr_flags;
}
void
update_iface(struct if_msghdr *ifm, struct sockaddr_dl *sdl)
{
struct iface *iface;
struct imsg_ifinfo ifinfo;
uint32_t if_index;
int flags, xflags;
char ifnamebuf[IF_NAMESIZE], *if_name;
if_index = ifm->ifm_index;
flags = ifm->ifm_flags;
xflags = ifm->ifm_xflags;
iface = get_iface_by_id(if_index);
if_name = if_indextoname(if_index, ifnamebuf);
if (if_name == NULL) {
if (iface != NULL) {
log_debug("interface with idx %d removed", if_index);
frontend_imsg_compose_engine(IMSG_REMOVE_IF, 0, 0,
&if_index, sizeof(if_index));
remove_iface(if_index);
}
return;
}
if (!(xflags & IFXF_AUTOCONF4)) {
if (iface != NULL) {
log_info("Removed autoconf flag from %s", if_name);
frontend_imsg_compose_engine(IMSG_REMOVE_IF, 0, 0,
&if_index, sizeof(if_index));
remove_iface(if_index);
}
return;
}
memset(&ifinfo, 0, sizeof(ifinfo));
ifinfo.if_index = if_index;
ifinfo.link_state = ifm->ifm_data.ifi_link_state;
ifinfo.rdomain = ifm->ifm_tableid;
ifinfo.running = (flags & (IFF_UP | IFF_RUNNING)) ==
(IFF_UP | IFF_RUNNING);
if (sdl != NULL && (sdl->sdl_type == IFT_ETHER ||
sdl->sdl_type == IFT_CARP) && sdl->sdl_alen == ETHER_ADDR_LEN)
memcpy(ifinfo.hw_address.ether_addr_octet, LLADDR(sdl),
ETHER_ADDR_LEN);
else if (iface == NULL) {
log_warnx("Could not find AF_LINK address for %s.", if_name);
return;
}
if (iface == NULL) {
if ((iface = calloc(1, sizeof(*iface))) == NULL)
fatal("calloc");
iface->udpsock = -1;
LIST_INSERT_HEAD(&interfaces, iface, entries);
frontend_imsg_compose_main(IMSG_OPEN_BPFSOCK, 0,
&if_index, sizeof(if_index));
} else {
if (iface->ifinfo.rdomain != ifinfo.rdomain &&
iface->udpsock != -1) {
close(iface->udpsock);
iface->udpsock = -1;
}
}
if (memcmp(&iface->ifinfo, &ifinfo, sizeof(iface->ifinfo)) != 0) {
memcpy(&iface->ifinfo, &ifinfo, sizeof(iface->ifinfo));
frontend_imsg_compose_main(IMSG_UPDATE_IF, 0, &iface->ifinfo,
sizeof(iface->ifinfo));
}
}
void
frontend_startup(void)
{
if (!event_initialized(&ev_route))
fatalx("%s: did not receive a route socket from the main "
"process", __func__);
init_ifaces();
if (pledge("stdio unix recvfd", NULL) == -1)
fatal("pledge");
event_add(&ev_route, NULL);
}
void
init_ifaces(void)
{
struct iface *iface;
struct imsg_ifinfo ifinfo;
struct if_nameindex *ifnidxp, *ifnidx;
struct ifaddrs *ifap, *ifa;
uint32_t if_index;
int flags, xflags;
char *if_name;
if ((ifnidxp = if_nameindex()) == NULL)
fatalx("if_nameindex");
if (getifaddrs(&ifap) != 0)
fatal("getifaddrs");
for (ifnidx = ifnidxp; ifnidx->if_index != 0 && ifnidx->if_name != NULL;
ifnidx++) {
if_index = ifnidx->if_index;
if_name = ifnidx->if_name;
if ((flags = get_flags(if_name)) == -1)
continue;
if ((xflags = get_xflags(if_name)) == -1)
continue;
if (!(xflags & IFXF_AUTOCONF4))
continue;
memset(&ifinfo, 0, sizeof(ifinfo));
ifinfo.if_index = if_index;
ifinfo.link_state = -1;
ifinfo.running = (flags & (IFF_UP | IFF_RUNNING)) ==
(IFF_UP | IFF_RUNNING);
for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
if (strcmp(if_name, ifa->ifa_name) != 0)
continue;
if (ifa->ifa_addr == NULL)
continue;
switch (ifa->ifa_addr->sa_family) {
case AF_LINK: {
struct if_data *if_data;
struct sockaddr_dl *sdl;
sdl = (struct sockaddr_dl *)ifa->ifa_addr;
if ((sdl->sdl_type != IFT_ETHER &&
sdl->sdl_type != IFT_CARP) ||
sdl->sdl_alen != ETHER_ADDR_LEN)
continue;
memcpy(ifinfo.hw_address.ether_addr_octet,
LLADDR(sdl), ETHER_ADDR_LEN);
if_data = (struct if_data *)ifa->ifa_data;
ifinfo.link_state = if_data->ifi_link_state;
ifinfo.rdomain = if_data->ifi_rdomain;
goto out;
}
default:
break;
}
}
out:
if (ifinfo.link_state == -1)
/* no AF_LINK found */
continue;
if ((iface = calloc(1, sizeof(*iface))) == NULL)
fatal("calloc");
iface->udpsock = -1;
memcpy(&iface->ifinfo, &ifinfo, sizeof(iface->ifinfo));
LIST_INSERT_HEAD(&interfaces, iface, entries);
frontend_imsg_compose_main(IMSG_OPEN_BPFSOCK, 0,
&if_index, sizeof(if_index));
frontend_imsg_compose_main(IMSG_UPDATE_IF, 0, &iface->ifinfo,
sizeof(iface->ifinfo));
}
freeifaddrs(ifap);
if_freenameindex(ifnidxp);
}
void
route_receive(int fd, short events, void *arg)
{
static uint8_t *buf;
struct rt_msghdr *rtm;
struct sockaddr *sa, *rti_info[RTAX_MAX];
ssize_t n;
if (buf == NULL) {
buf = malloc(ROUTE_SOCKET_BUF_SIZE);
if (buf == NULL)
fatal("malloc");
}
rtm = (struct rt_msghdr *)buf;
if ((n = read(fd, buf, ROUTE_SOCKET_BUF_SIZE)) == -1) {
if (errno == EAGAIN || errno == EINTR)
return;
log_warn("dispatch_rtmsg: read error");
return;
}
if (n == 0)
fatal("routing socket closed");
if (n < (ssize_t)sizeof(rtm->rtm_msglen) || n < rtm->rtm_msglen) {
log_warnx("partial rtm of %zd in buffer", n);
return;
}
if (rtm->rtm_version != RTM_VERSION)
return;
sa = (struct sockaddr *)(buf + rtm->rtm_hdrlen);
get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
handle_route_message(rtm, rti_info);
}
void
handle_route_message(struct rt_msghdr *rtm, struct sockaddr **rti_info)
{
struct sockaddr_dl *sdl = NULL;
struct if_announcemsghdr *ifan;
uint32_t if_index;
switch (rtm->rtm_type) {
case RTM_IFINFO:
if (rtm->rtm_addrs & RTA_IFP && rti_info[RTAX_IFP]->sa_family
== AF_LINK)
sdl = (struct sockaddr_dl *)rti_info[RTAX_IFP];
update_iface((struct if_msghdr *)rtm, sdl);
break;
case RTM_IFANNOUNCE:
ifan = (struct if_announcemsghdr *)rtm;
if_index = ifan->ifan_index;
if (ifan->ifan_what == IFAN_DEPARTURE) {
frontend_imsg_compose_engine(IMSG_REMOVE_IF, 0, 0,
&if_index, sizeof(if_index));
remove_iface(if_index);
}
break;
case RTM_PROPOSAL:
if (rtm->rtm_priority == RTP_PROPOSAL_SOLICIT) {
log_debug("RTP_PROPOSAL_SOLICIT");
frontend_imsg_compose_engine(IMSG_REPROPOSE_RDNS,
0, 0, NULL, 0);
}
#ifndef SMALL
else if (rtm->rtm_flags & RTF_PROTO3) {
char ifnamebuf[IF_NAMESIZE], *if_name;
if_index = rtm->rtm_index;
if_name = if_indextoname(if_index, ifnamebuf);
log_warnx("\"dhclient %s\" ran, requesting new lease",
if_name != NULL ? if_name : "(unknown)");
frontend_imsg_compose_engine(IMSG_REQUEST_REBOOT,
0, 0, &if_index, sizeof(if_index));
}
#endif /* SMALL */
break;
default:
log_debug("unexpected RTM: %d", rtm->rtm_type);
break;
}
}
#define ROUNDUP(a) \
((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
void
get_rtaddrs(int addrs, struct sockaddr *sa, struct sockaddr **rti_info)
{
int i;
for (i = 0; i < RTAX_MAX; i++) {
if (addrs & (1 << i)) {
rti_info[i] = sa;
sa = (struct sockaddr *)((char *)(sa) +
ROUNDUP(sa->sa_len));
} else
rti_info[i] = NULL;
}
}
void
bpf_receive(int fd, short events, void *arg)
{
struct bpf_hdr *hdr;
struct imsg_dhcp imsg_dhcp;
struct iface *iface;
ssize_t len, rem;
uint8_t *p;
iface = (struct iface *)arg;
if ((len = read(fd, iface->bpfev.buf, BPFLEN)) == -1) {
log_warn("%s: read", __func__);
return;
}
if (len == 0)
fatal("%s len == 0", __func__);
memset(&imsg_dhcp, 0, sizeof(imsg_dhcp));
imsg_dhcp.if_index = iface->ifinfo.if_index;
rem = len;
p = iface->bpfev.buf;
while (rem > 0) {
if ((size_t)rem < sizeof(*hdr)) {
log_warnx("packet too short");
return;
}
hdr = (struct bpf_hdr *)p;
if (hdr->bh_caplen != hdr->bh_datalen) {
log_warnx("skipping truncated packet");
goto cont;
}
if (rem < hdr->bh_hdrlen + hdr->bh_caplen)
/* we are done */
break;
if (hdr->bh_caplen > sizeof(imsg_dhcp.packet)) {
log_warn("packet too big");
goto cont;
}
memcpy(&imsg_dhcp.packet, p + hdr->bh_hdrlen, hdr->bh_caplen);
imsg_dhcp.len = hdr->bh_caplen;
imsg_dhcp.csumflags = hdr->bh_csumflags;
frontend_imsg_compose_engine(IMSG_DHCP, 0, 0, &imsg_dhcp,
sizeof(imsg_dhcp));
cont:
p += BPF_WORDALIGN(hdr->bh_hdrlen + hdr->bh_caplen);
rem -= BPF_WORDALIGN(hdr->bh_hdrlen + hdr->bh_caplen);
}
}
void
iface_data_from_imsg(struct iface* iface, struct imsg_req_dhcp *imsg)
{
iface->xid = imsg->xid;
iface->ciaddr = imsg->ciaddr;
iface->requested_ip = imsg->requested_ip;
iface->server_identifier = imsg->server_identifier;
iface->dhcp_server = imsg->dhcp_server;
}
ssize_t
build_packet(uint8_t message_type, char *if_name, uint32_t xid,
struct ether_addr *hw_address, struct in_addr *ciaddr, struct in_addr
*requested_ip, struct in_addr *server_identifier)
{
static uint8_t dhcp_cookie[] = DHCP_COOKIE;
static uint8_t dhcp_message_type[] = {DHO_DHCP_MESSAGE_TYPE, 1,
DHCPDISCOVER};
static uint8_t dhcp_hostname[255 + 2] = {DHO_HOST_NAME, 0 /*, ... */};
static uint8_t dhcp_client_id[] = {DHO_DHCP_CLIENT_IDENTIFIER, 7,
HTYPE_ETHER, 0, 0, 0, 0, 0, 0};
static uint8_t dhcp_req_list[] = {DHO_DHCP_PARAMETER_REQUEST_LIST,
8, DHO_SUBNET_MASK, DHO_ROUTERS, DHO_DOMAIN_NAME_SERVERS,
DHO_HOST_NAME, DHO_DOMAIN_NAME, DHO_BROADCAST_ADDRESS,
DHO_DOMAIN_SEARCH, DHO_CLASSLESS_STATIC_ROUTES};
static uint8_t dhcp_req_list_v6[] = {DHO_DHCP_PARAMETER_REQUEST_LIST,
9, DHO_SUBNET_MASK, DHO_ROUTERS, DHO_DOMAIN_NAME_SERVERS,
DHO_HOST_NAME, DHO_DOMAIN_NAME, DHO_BROADCAST_ADDRESS,
DHO_DOMAIN_SEARCH, DHO_CLASSLESS_STATIC_ROUTES,
DHO_IPV6_ONLY_PREFERRED};
static uint8_t dhcp_requested_address[] = {DHO_DHCP_REQUESTED_ADDRESS,
4, 0, 0, 0, 0};
static uint8_t dhcp_server_identifier[] = {DHO_DHCP_SERVER_IDENTIFIER,
4, 0, 0, 0, 0};
#ifndef SMALL
struct iface_conf *iface_conf;
#endif /* SMALL */
struct dhcp_hdr *hdr;
ssize_t len;
uint8_t *p;
char *c;
#ifndef SMALL
iface_conf = find_iface_conf(&frontend_conf->iface_list, if_name);
#endif /* SMALL */
memset(dhcp_packet, 0, sizeof(dhcp_packet));
dhcp_message_type[2] = message_type;
p = dhcp_packet;
hdr = (struct dhcp_hdr *)p;
hdr->op = DHCP_BOOTREQUEST;
hdr->htype = HTYPE_ETHER;
hdr->hlen = 6;
hdr->hops = 0;
hdr->xid = htonl(xid);
hdr->secs = 0;
hdr->ciaddr = *ciaddr;
memcpy(hdr->chaddr, hw_address, sizeof(*hw_address));
p += sizeof(struct dhcp_hdr);
memcpy(p, dhcp_cookie, sizeof(dhcp_cookie));
p += sizeof(dhcp_cookie);
memcpy(p, dhcp_message_type, sizeof(dhcp_message_type));
p += sizeof(dhcp_message_type);
#ifndef SMALL
if (iface_conf != NULL && iface_conf->h_name != NULL) {
if (iface_conf->h_name[0] != '\0') {
dhcp_hostname[1] = strlen(iface_conf->h_name);
memcpy(dhcp_hostname + 2, iface_conf->h_name,
strlen(iface_conf->h_name));
memcpy(p, dhcp_hostname, dhcp_hostname[1] + 2);
p += dhcp_hostname[1] + 2;
}
} else
#endif /* SMALL */
{
if (gethostname(dhcp_hostname + 2,
sizeof(dhcp_hostname) - 2) == 0 &&
dhcp_hostname[2] != '\0') {
if ((c = strchr(dhcp_hostname + 2, '.')) != NULL)
*c = '\0';
dhcp_hostname[1] = strlen(dhcp_hostname + 2);
memcpy(p, dhcp_hostname, dhcp_hostname[1] + 2);
p += dhcp_hostname[1] + 2;
}
}
#ifndef SMALL
if (iface_conf != NULL) {
if (iface_conf->c_id_len > 0) {
/* XXX check space */
memcpy(p, iface_conf->c_id, iface_conf->c_id_len);
p += iface_conf->c_id_len;
} else {
memcpy(dhcp_client_id + 3, hw_address, sizeof(*hw_address));
memcpy(p, dhcp_client_id, sizeof(dhcp_client_id));
p += sizeof(dhcp_client_id);
}
if (iface_conf->vc_id_len > 0) {
/* XXX check space */
memcpy(p, iface_conf->vc_id, iface_conf->vc_id_len);
p += iface_conf->vc_id_len;
}
if (iface_conf->prefer_ipv6) {
memcpy(p, dhcp_req_list_v6, sizeof(dhcp_req_list_v6));
p += sizeof(dhcp_req_list_v6);
} else {
memcpy(p, dhcp_req_list, sizeof(dhcp_req_list));
p += sizeof(dhcp_req_list);
}
} else
#endif /* SMALL */
{
memcpy(dhcp_client_id + 3, hw_address, sizeof(*hw_address));
memcpy(p, dhcp_client_id, sizeof(dhcp_client_id));
p += sizeof(dhcp_client_id);
memcpy(p, dhcp_req_list, sizeof(dhcp_req_list));
p += sizeof(dhcp_req_list);
}
if (requested_ip->s_addr != INADDR_ANY) {
memcpy(dhcp_requested_address + 2, requested_ip,
sizeof(*requested_ip));
memcpy(p, dhcp_requested_address,
sizeof(dhcp_requested_address));
p += sizeof(dhcp_requested_address);
}
if (server_identifier->s_addr != INADDR_ANY) {
memcpy(dhcp_server_identifier + 2, server_identifier,
sizeof(*server_identifier));
memcpy(p, dhcp_server_identifier,
sizeof(dhcp_server_identifier));
p += sizeof(dhcp_server_identifier);
}
*p = DHO_END;
p += 1;
len = p - dhcp_packet;
/* dhcp_packet is initialized with DHO_PADs */
if (len < BOOTP_MIN_LEN)
len = BOOTP_MIN_LEN;
return (len);
}
void
send_packet(uint8_t message_type, struct iface *iface)
{
ssize_t pkt_len;
char ifnamebuf[IF_NAMESIZE], *if_name;
if (!event_initialized(&iface->bpfev.ev)) {
iface->send_discover = 1;
return;
}
iface->send_discover = 0;
if ((if_name = if_indextoname(iface->ifinfo.if_index, ifnamebuf)) == NULL)
return; /* iface went away, nothing to do */
log_debug("%s on %s", message_type == DHCPDISCOVER ? "DHCPDISCOVER" :
"DHCPREQUEST", if_name);
pkt_len = build_packet(message_type, if_name, iface->xid,
&iface->ifinfo.hw_address, &iface->ciaddr, &iface->requested_ip,
&iface->server_identifier);
if (iface->dhcp_server.s_addr != INADDR_ANY) {
if (udp_send_packet(iface, dhcp_packet, pkt_len) == -1)
bpf_send_packet(iface, dhcp_packet, pkt_len);
} else
bpf_send_packet(iface, dhcp_packet, pkt_len);
}
int
udp_send_packet(struct iface *iface, uint8_t *packet, ssize_t len)
{
struct sockaddr_in to;
memset(&to, 0, sizeof(to));
to.sin_family = AF_INET;
to.sin_len = sizeof(to);
to.sin_addr = iface->dhcp_server;
to.sin_port = ntohs(SERVER_PORT);
if (sendto(iface->udpsock, packet, len, 0, (struct sockaddr *)&to,
sizeof(to)) == -1) {
log_warn("sendto");
return -1;
}
return 0;
}
void
bpf_send_packet(struct iface *iface, uint8_t *packet, ssize_t len)
{
struct iovec iov[4];
struct ether_header eh;
struct ip ip;
struct udphdr udp;
ssize_t total, result;
int iovcnt = 0, i;
memset(eh.ether_dhost, 0xff, sizeof(eh.ether_dhost));
memcpy(eh.ether_shost, &iface->ifinfo.hw_address,
sizeof(eh.ether_dhost));
eh.ether_type = htons(ETHERTYPE_IP);
iov[0].iov_base = &eh;
iov[0].iov_len = sizeof(eh);
iovcnt++;
ip.ip_v = 4;
ip.ip_hl = 5;
ip.ip_tos = IPTOS_LOWDELAY;
ip.ip_len = htons(sizeof(ip) + sizeof(udp) + len);
ip.ip_id = 0;
ip.ip_off = 0;
ip.ip_ttl = 128;
ip.ip_p = IPPROTO_UDP;
ip.ip_sum = 0;
ip.ip_src.s_addr = INADDR_ANY;
ip.ip_dst.s_addr = INADDR_BROADCAST;
ip.ip_sum = wrapsum(checksum((unsigned char *)&ip, sizeof(ip), 0));
iov[iovcnt].iov_base = &ip;
iov[iovcnt].iov_len = sizeof(ip);
iovcnt++;
udp.uh_sport = htons(CLIENT_PORT);
udp.uh_dport = htons(SERVER_PORT);
udp.uh_ulen = htons(sizeof(udp) + len);
udp.uh_sum = 0;
udp.uh_sum = wrapsum(checksum((unsigned char *)&udp, sizeof(udp),
checksum((unsigned char *)packet, len,
checksum((unsigned char *)&ip.ip_src,
2 * sizeof(ip.ip_src),
IPPROTO_UDP + (uint32_t)ntohs(udp.uh_ulen)))));
iov[iovcnt].iov_base = &udp;
iov[iovcnt].iov_len = sizeof(udp);
iovcnt++;
iov[iovcnt].iov_base = packet;
iov[iovcnt].iov_len = len;
iovcnt++;
total = 0;
for (i = 0; i < iovcnt; i++)
total += iov[i].iov_len;
result = writev(EVENT_FD(&iface->bpfev.ev), iov, iovcnt);
if (result == -1)
log_warn("%s: writev", __func__);
else if (result < total) {
log_warnx("%s, writev: %zd of %zd bytes", __func__, result,
total);
}
}
struct iface*
get_iface_by_id(uint32_t if_index)
{
struct iface *iface;
LIST_FOREACH (iface, &interfaces, entries) {
if (iface->ifinfo.if_index == if_index)
return (iface);
}
return (NULL);
}
void
remove_iface(uint32_t if_index)
{
struct iface *iface;
iface = get_iface_by_id(if_index);
if (iface == NULL)
return;
LIST_REMOVE(iface, entries);
if (event_initialized(&iface->bpfev.ev)) {
event_del(&iface->bpfev.ev);
close(EVENT_FD(&iface->bpfev.ev));
}
if (iface->udpsock != -1)
close(iface->udpsock);
free(iface);
}
void
set_bpfsock(int bpfsock, uint32_t if_index)
{
struct iface *iface;
iface = get_iface_by_id(if_index);
if (iface == NULL) {
/*
* The interface disappeared while we were waiting for the
* parent process to open the bpf socket.
*/
close(bpfsock);
} else if (event_initialized(&iface->bpfev.ev)) {
/*
* The autoconf flag is flapping and we have multiple bpf sockets in
* flight. We don't need this one because we already got one.
*/
close(bpfsock);
} else {
event_set(&iface->bpfev.ev, bpfsock, EV_READ |
EV_PERSIST, bpf_receive, iface);
event_add(&iface->bpfev.ev, NULL);
if (iface->send_discover)
send_packet(DHCPDISCOVER, iface);
}
}
#ifndef SMALL
struct iface_conf*
find_iface_conf(struct iface_conf_head *head, char *if_name)
{
struct iface_conf *iface_conf;
if (if_name == NULL)
return (NULL);
SIMPLEQ_FOREACH(iface_conf, head, entry) {
if (strcmp(iface_conf->name, if_name) == 0)
return iface_conf;
}
return (NULL);
}
int*
changed_ifaces(struct dhcpleased_conf *oconf, struct dhcpleased_conf *nconf)
{
struct iface_conf *iface_conf, *oiface_conf;
int *ret, if_index, count = 0, i = 0;
/*
* Worst case: All old interfaces replaced with new interfaces.
* This should still be a small number
*/
SIMPLEQ_FOREACH(iface_conf, &oconf->iface_list, entry)
count++;
SIMPLEQ_FOREACH(iface_conf, &nconf->iface_list, entry)
count++;
ret = calloc(count + 1, sizeof(int));
SIMPLEQ_FOREACH(iface_conf, &nconf->iface_list, entry) {
if ((if_index = if_nametoindex(iface_conf->name)) == 0)
continue;
oiface_conf = find_iface_conf(&oconf->iface_list,
iface_conf->name);
if (oiface_conf == NULL) {
/* new interface added to config */
ret[i++] = if_index;
} else if (iface_conf_cmp(iface_conf, oiface_conf) != 0) {
/* interface conf changed */
ret[i++] = if_index;
}
}
SIMPLEQ_FOREACH(oiface_conf, &oconf->iface_list, entry) {
if ((if_index = if_nametoindex(oiface_conf->name)) == 0)
continue;
if (find_iface_conf(&nconf->iface_list, oiface_conf->name) ==
NULL) {
/* interface removed from config */
ret[i++] = if_index;
}
}
return ret;
}
int
iface_conf_cmp(struct iface_conf *a, struct iface_conf *b)
{
if (a->vc_id_len != b->vc_id_len)
return 1;
if (memcmp(a->vc_id, b->vc_id, a->vc_id_len) != 0)
return 1;
if (a->c_id_len != b->c_id_len)
return 1;
if (memcmp(a->c_id, b->c_id, a->c_id_len) != 0)
return 1;
if (a->h_name == NULL || b->h_name == NULL)
return 1;
if (strcmp(a->h_name, b->h_name) != 0)
return 1;
if (a->ignore != b->ignore)
return 1;
if (a->ignore_servers_len != b->ignore_servers_len)
return 1;
if (memcmp(a->ignore_servers, b->ignore_servers,
a->ignore_servers_len * sizeof (struct in_addr)) != 0)
return 1;
return 0;
}
#endif /* SMALL */
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