/***
This file is part of avahi.
avahi 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.
avahi 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 avahi; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA.
***/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <sys/param.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/wait.h>
#ifdef __FreeBSD__
#include <sys/sysctl.h>
#endif
#ifdef __linux__
#include <netpacket/packet.h>
#endif
#include <net/ethernet.h>
#include <net/if.h>
#ifdef __FreeBSD__
#include <net/if_dl.h>
#include <net/route.h>
#endif
#include <arpa/inet.h>
#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <signal.h>
#include <string.h>
#include <time.h>
#include <getopt.h>
#include <grp.h>
#include <poll.h>
#include <pwd.h>
#include <unistd.h>
#ifndef __linux__
#include <pcap.h>
/* Old versions of PCAP defined it as D_IN */
#ifndef PCAP_D_IN
#define PCAP_D_IN D_IN
#endif
#endif
#include "avahi-common/avahi-malloc.h"
#include <avahi-common/timeval.h>
#include <avahi-daemon/setproctitle.h>
#include <libdaemon/dfork.h>
#include <libdaemon/dsignal.h>
#include <libdaemon/dlog.h>
#include <libdaemon/dpid.h>
#include <libdaemon/dexec.h>
#include "main.h"
#include "iface.h"
/* An implementation of RFC 3927 */
/* Constants from the RFC */
#define PROBE_WAIT 1
#define PROBE_NUM 3
#define PROBE_MIN 1
#define PROBE_MAX 2
#define ANNOUNCE_WAIT 2
#define ANNOUNCE_NUM 2
#define ANNOUNCE_INTERVAL 2
#define MAX_CONFLICTS 10
#define RATE_LIMIT_INTERVAL 60
#define DEFEND_INTERVAL 10
#define IPV4LL_NETWORK 0xA9FE0000L
#define IPV4LL_NETMASK 0xFFFF0000L
#define IPV4LL_HOSTMASK 0x0000FFFFL
#define IPV4LL_BROADCAST 0xA9FEFFFFL
#define ETHER_ADDRLEN 6
#define ETHER_HDR_SIZE (2+2*ETHER_ADDRLEN)
#define ARP_PACKET_SIZE (8+4+4+2*ETHER_ADDRLEN)
typedef enum ArpOperation {
ARP_REQUEST = 1,
ARP_RESPONSE = 2
} ArpOperation;
typedef struct ArpPacketInfo {
ArpOperation operation;
uint32_t sender_ip_address, target_ip_address;
uint8_t sender_hw_address[ETHER_ADDRLEN], target_hw_address[ETHER_ADDRLEN];
} ArpPacketInfo;
typedef struct ArpPacket {
uint8_t *ether_header;
uint8_t *ether_payload;
} ArpPacket;
static State state = STATE_START;
static int n_iteration = 0;
static int n_conflict = 0;
static char *interface_name = NULL;
static char *pid_file_name = NULL;
static uint32_t start_address = 0;
static char *argv0 = NULL;
static int daemonize = 0;
static int wait_for_address = 0;
static int use_syslog = 0;
static int debug = 0;
static int modify_proc_title = 1;
static int force_bind = 0;
#ifdef HAVE_CHROOT
static int no_chroot = 0;
#endif
static int no_drop_root = 0;
static int wrote_pid_file = 0;
static char *action_script = NULL;
static enum {
DAEMON_RUN,
DAEMON_KILL,
DAEMON_REFRESH,
DAEMON_VERSION,
DAEMON_HELP,
DAEMON_CHECK
} command = DAEMON_RUN;
typedef enum CalloutEvent {
CALLOUT_BIND,
CALLOUT_CONFLICT,
CALLOUT_UNBIND,
CALLOUT_STOP,
CALLOUT_MAX
} CalloutEvent;
static const char * const callout_event_table[CALLOUT_MAX] = {
[CALLOUT_BIND] = "BIND",
[CALLOUT_CONFLICT] = "CONFLICT",
[CALLOUT_UNBIND] = "UNBIND",
[CALLOUT_STOP] = "STOP"
};
typedef struct CalloutEventInfo {
CalloutEvent event;
uint32_t address;
int ifindex;
} CalloutEventInfo;
#define RANDOM_DEVICE "/dev/urandom"
#define DEBUG(x) \
do { \
if (debug) { \
x; \
} \
} while (0)
static void init_rand_seed(void) {
int fd;
unsigned seed = 0;
/* Try to initialize seed from /dev/urandom, to make it a little
* less predictable, and to make sure that multiple machines
* booted at the same time choose different random seeds. */
if ((fd = open(RANDOM_DEVICE, O_RDONLY)) >= 0) {
read(fd, &seed, sizeof(seed));
close(fd);
}
/* If the initialization failed by some reason, we add the time to the seed */
seed ^= (unsigned) time(NULL);
srand(seed);
}
static uint32_t pick_addr(uint32_t old_addr) {
uint32_t addr;
do {
unsigned r = (unsigned) rand();
/* Reduce to 16 bits */
while (r > 0xFFFF)
r = (r >> 16) ^ (r & 0xFFFF);
addr = htonl(IPV4LL_NETWORK | (uint32_t) r);
} while (addr == old_addr || !is_ll_address(addr));
return addr;
}
static int load_address(const char *fn, uint32_t *addr) {
FILE *f;
unsigned a, b, c, d;
assert(fn);
assert(addr);
if (!(f = fopen(fn, "r"))) {
if (errno == ENOENT) {
*addr = 0;
return 0;
}
daemon_log(LOG_ERR, "fopen() failed: %s", strerror(errno));
goto fail;
}
if (fscanf(f, "%u.%u.%u.%u\n", &a, &b, &c, &d) != 4) {
daemon_log(LOG_ERR, "Parse failure");
goto fail;
}
fclose(f);
*addr = htonl((a << 24) | (b << 16) | (c << 8) | d);
return 0;
fail:
if (f)
fclose(f);
return -1;
}
static int save_address(const char *fn, uint32_t addr) {
FILE *f;
char buf[32];
mode_t u;
assert(fn);
u = umask(0033);
if (!(f = fopen(fn, "w"))) {
daemon_log(LOG_ERR, "fopen() failed: %s", strerror(errno));
goto fail;
}
umask(u);
fprintf(f, "%s\n", inet_ntop(AF_INET, &addr, buf, sizeof (buf)));
fclose(f);
return 0;
fail:
if (f)
fclose(f);
umask(u);
return -1;
}
/*
* Allocate a buffer with two pointers in front, one of which is
* guaranteed to point ETHER_HDR_SIZE bytes into it.
*/
static ArpPacket* packet_new(size_t packet_len) {
ArpPacket *p;
uint8_t *b;
assert(packet_len > 0);
#ifdef __linux__
b = avahi_new0(uint8_t, sizeof(struct ArpPacket) + packet_len);
p = (ArpPacket*) b;
p->ether_header = NULL;
p->ether_payload = b + sizeof(struct ArpPacket);
#else
b = avahi_new0(uint8_t, sizeof(struct ArpPacket) + ETHER_HDR_SIZE + packet_len);
p = (ArpPacket*) b;
p->ether_header = b + sizeof(struct ArpPacket);
p->ether_payload = b + sizeof(struct ArpPacket) + ETHER_HDR_SIZE;
#endif
return p;
}
static ArpPacket* packet_new_with_info(const ArpPacketInfo *info, size_t *packet_len) {
ArpPacket *p = NULL;
uint8_t *r;
assert(info);
assert(info->operation == ARP_REQUEST || info->operation == ARP_RESPONSE);
assert(packet_len != NULL);
*packet_len = ARP_PACKET_SIZE;
p = packet_new(*packet_len);
r = p->ether_payload;
r[1] = 1; /* HTYPE */
r[2] = 8; /* PTYPE */
r[4] = ETHER_ADDRLEN; /* HLEN */
r[5] = 4; /* PLEN */
r[7] = (uint8_t) info->operation;
memcpy(r+8, info->sender_hw_address, ETHER_ADDRLEN);
memcpy(r+14, &info->sender_ip_address, 4);
memcpy(r+18, info->target_hw_address, ETHER_ADDRLEN);
memcpy(r+24, &info->target_ip_address, 4);
return p;
}
static ArpPacket *packet_new_probe(uint32_t ip_address, const uint8_t*hw_address, size_t *packet_len) {
ArpPacketInfo info;
memset(&info, 0, sizeof(info));
info.operation = ARP_REQUEST;
memcpy(info.sender_hw_address, hw_address, ETHER_ADDRLEN);
info.target_ip_address = ip_address;
return packet_new_with_info(&info, packet_len);
}
static ArpPacket *packet_new_announcement(uint32_t ip_address, const uint8_t* hw_address, size_t *packet_len) {
ArpPacketInfo info;
memset(&info, 0, sizeof(info));
info.operation = ARP_REQUEST;
memcpy(info.sender_hw_address, hw_address, ETHER_ADDRLEN);
info.target_ip_address = ip_address;
info.sender_ip_address = ip_address;
return packet_new_with_info(&info, packet_len);
}
static int packet_parse(const ArpPacket *packet, size_t packet_len, ArpPacketInfo *info) {
const uint8_t *p;
assert(packet);
p = (uint8_t *)packet->ether_payload;
assert(p);
if (packet_len < ARP_PACKET_SIZE)
return -1;
/* Check HTYPE and PTYPE */
if (p[0] != 0 || p[1] != 1 || p[2] != 8 || p[3] != 0)
return -1;
/* Check HLEN, PLEN, OPERATION */
if (p[4] != ETHER_ADDRLEN || p[5] != 4 || p[6] != 0 || (p[7] != 1 && p[7] != 2))
return -1;
info->operation = p[7];
memcpy(info->sender_hw_address, p+8, ETHER_ADDRLEN);
memcpy(&info->sender_ip_address, p+14, 4);
memcpy(info->target_hw_address, p+18, ETHER_ADDRLEN);
memcpy(&info->target_ip_address, p+24, 4);
return 0;
}
static void set_state(State st, int reset_counter, uint32_t address) {
static const char* const state_table[] = {
[STATE_START] = "START",
[STATE_WAITING_PROBE] = "WAITING_PROBE",
[STATE_PROBING] = "PROBING",
[STATE_WAITING_ANNOUNCE] = "WAITING_ANNOUNCE",
[STATE_ANNOUNCING] = "ANNOUNCING",
[STATE_RUNNING] = "RUNNING",
[STATE_SLEEPING] = "SLEEPING"
};
char buf[64];
assert(st < STATE_MAX);
if (st == state && !reset_counter) {
n_iteration++;
DEBUG(daemon_log(LOG_DEBUG, "State iteration %s-%i", state_table[state], n_iteration));
} else {
DEBUG(daemon_log(LOG_DEBUG, "State transition %s-%i -> %s-0", state_table[state], n_iteration, state_table[st]));
state = st;
n_iteration = 0;
}
if (state == STATE_SLEEPING)
avahi_set_proc_title(argv0, "%s: [%s] sleeping", argv0, interface_name);
else if (state == STATE_ANNOUNCING)
avahi_set_proc_title(argv0, "%s: [%s] announcing %s", argv0, interface_name, inet_ntop(AF_INET, &address, buf, sizeof(buf)));
else if (state == STATE_RUNNING)
avahi_set_proc_title(argv0, "%s: [%s] bound %s", argv0, interface_name, inet_ntop(AF_INET, &address, buf, sizeof(buf)));
else
avahi_set_proc_title(argv0, "%s: [%s] probing %s", argv0, interface_name, inet_ntop(AF_INET, &address, buf, sizeof(buf)));
}
static int interface_up(int iface) {
int fd = -1;
struct ifreq ifreq;
if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
daemon_log(LOG_ERR, "socket() failed: %s", strerror(errno));
goto fail;
}
memset(&ifreq, 0, sizeof(ifreq));
if (!if_indextoname(iface, ifreq.ifr_name)) {
daemon_log(LOG_ERR, "if_indextoname() failed: %s", strerror(errno));
goto fail;
}
if (ioctl(fd, SIOCGIFFLAGS, &ifreq) < 0) {
daemon_log(LOG_ERR, "SIOCGIFFLAGS failed: %s", strerror(errno));
goto fail;
}
ifreq.ifr_flags |= IFF_UP;
if (ioctl(fd, SIOCSIFFLAGS, &ifreq) < 0) {
daemon_log(LOG_ERR, "SIOCSIFFLAGS failed: %s", strerror(errno));
goto fail;
}
close(fd);
return 0;
fail:
if (fd >= 0)
close(fd);
return -1;
}
#ifdef __linux__
/* Linux 'packet socket' specific implementation */
static int open_socket(int iface, uint8_t *hw_address) {
int fd = -1;
struct sockaddr_ll sa;
socklen_t sa_len;
if (interface_up(iface) < 0)
goto fail;
if ((fd = socket(PF_PACKET, SOCK_DGRAM, 0)) < 0) {
daemon_log(LOG_ERR, "socket() failed: %s", strerror(errno));
goto fail;
}
memset(&sa, 0, sizeof(sa));
sa.sll_family = AF_PACKET;
sa.sll_protocol = htons(ETH_P_ARP);
sa.sll_ifindex = iface;
if (bind(fd, (struct sockaddr*) &sa, sizeof(sa)) < 0) {
daemon_log(LOG_ERR, "bind() failed: %s", strerror(errno));
goto fail;
}
sa_len = sizeof(sa);
if (getsockname(fd, (struct sockaddr*) &sa, &sa_len) < 0) {
daemon_log(LOG_ERR, "getsockname() failed: %s", strerror(errno));
goto fail;
}
if (sa.sll_halen != ETHER_ADDRLEN) {
daemon_log(LOG_ERR, "getsockname() returned invalid hardware address.");
goto fail;
}
memcpy(hw_address, sa.sll_addr, ETHER_ADDRLEN);
return fd;
fail:
if (fd >= 0)
close(fd);
return -1;
}
static int send_packet(int fd, int iface, ArpPacket *packet, size_t packet_len) {
struct sockaddr_ll sa;
assert(fd >= 0);
assert(packet);
assert(packet_len > 0);
memset(&sa, 0, sizeof(sa));
sa.sll_family = AF_PACKET;
sa.sll_protocol = htons(ETH_P_ARP);
sa.sll_ifindex = iface;
sa.sll_halen = ETHER_ADDRLEN;
memset(sa.sll_addr, 0xFF, ETHER_ADDRLEN);
if (sendto(fd, packet->ether_payload, packet_len, 0, (struct sockaddr*) &sa, sizeof(sa)) < 0) {
daemon_log(LOG_ERR, "sendto() failed: %s", strerror(errno));
return -1;
}
return 0;
}
static int recv_packet(int fd, ArpPacket **packet, size_t *packet_len) {
int s;
struct sockaddr_ll sa;
socklen_t sa_len;
ssize_t r;
assert(fd >= 0);
assert(packet);
assert(packet_len);
*packet = NULL;
if (ioctl(fd, FIONREAD, &s) < 0) {
daemon_log(LOG_ERR, "FIONREAD failed: %s", strerror(errno));
goto fail;
}
if (s <= 0)
s = 4096;
*packet = packet_new(s);
sa_len = sizeof(sa);
if ((r = recvfrom(fd, (*packet)->ether_payload, s, 0, (struct sockaddr*) &sa, &sa_len)) < 0) {
daemon_log(LOG_ERR, "recvfrom() failed: %s", strerror(errno));
goto fail;
}
*packet_len = (size_t) r;
return 0;
fail:
if (*packet) {
avahi_free(*packet);
*packet = NULL;
}
return -1;
}
static void close_socket(int fd) {
close(fd);
}
#else /* !__linux__ */
/* PCAP-based implementation */
static pcap_t *__pp;
static char __pcap_errbuf[PCAP_ERRBUF_SIZE];
static uint8_t __lladdr[ETHER_ADDRLEN];
#ifndef elementsof
#define elementsof(array) (sizeof(array)/sizeof(array[0]))
#endif
static int __get_ether_addr(int ifindex, u_char *lladdr) {
int mib[6];
char *buf;
struct if_msghdr *ifm;
char *lim;
char *next;
struct sockaddr_dl *sdl;
size_t len;
mib[0] = CTL_NET;
mib[1] = PF_ROUTE;
mib[2] = 0;
mib[3] = 0;
mib[4] = NET_RT_IFLIST;
mib[5] = ifindex;
if (sysctl(mib, elementsof(mib), NULL, &len, NULL, 0) != 0) {
daemon_log(LOG_ERR, "sysctl(NET_RT_IFLIST): %s",
strerror(errno));
return -1;
}
buf = avahi_malloc(len);
if (sysctl(mib, elementsof(mib), buf, &len, NULL, 0) != 0) {
daemon_log(LOG_ERR, "sysctl(NET_RT_IFLIST): %s",
strerror(errno));
free(buf);
return -1;
}
lim = buf + len;
for (next = buf; next < lim; next += ifm->ifm_msglen) {
ifm = (struct if_msghdr *)next;
if (ifm->ifm_type == RTM_IFINFO) {
sdl = (struct sockaddr_dl *)(ifm + 1);
memcpy(lladdr, LLADDR(sdl), ETHER_ADDRLEN);
}
}
avahi_free(buf);
return 0;
}
#define PCAP_TIMEOUT 500 /* 0.5s */
static int open_socket(int iface, uint8_t *hw_address) {
struct bpf_program bpf;
char *filter;
char ifname[IFNAMSIZ];
pcap_t *pp;
int err;
int fd;
assert(__pp == NULL);
if (interface_up(iface) < 0)
return -1;
if (__get_ether_addr(iface, __lladdr) == -1)
return -1;
if (if_indextoname(iface, ifname) == NULL)
return -1;
/*
* Using a timeout for BPF is fairly portable across BSDs. On most
* modern versions, using the timeout/nonblock/poll method results in
* fairly sane behavior, with the timeout only coming into play during
* the next_ex() call itself (so, for us, that's only when there's
* data). On older versions, it may result in a PCAP_TIMEOUT busy-wait
* on some versions, though, as the poll() may terminate at the
* PCAP_TIMEOUT instead of the poll() timeout.
*/
pp = pcap_open_live(ifname, 1500, 0, PCAP_TIMEOUT, __pcap_errbuf);
if (pp == NULL) {
return (-1);
}
err = pcap_set_datalink(pp, DLT_EN10MB);
if (err == -1) {
daemon_log(LOG_ERR, "pcap_set_datalink: %s", pcap_geterr(pp));
pcap_close(pp);
return (-1);
}
err = pcap_setdirection(pp, PCAP_D_IN);
if (err == -1) {
daemon_log(LOG_ERR, "pcap_setdirection: %s", pcap_geterr(pp));
pcap_close(pp);
return (-1);
}
fd = pcap_get_selectable_fd(pp);
if (fd == -1) {
pcap_close(pp);
return (-1);
}
/*
* Using setnonblock is a portability stop-gap. Using the timeout in
* combination with setnonblock will ensure on most BSDs that the
* next_ex call returns in a timely fashion.
*/
err = pcap_setnonblock(pp, 1, __pcap_errbuf);
if (err == -1) {
pcap_close(pp);
return (-1);
}
filter = avahi_strdup_printf("arp and (ether dst ff:ff:ff:ff:ff:ff or "
"%02x:%02x:%02x:%02x:%02x:%02x)",
__lladdr[0], __lladdr[1],
__lladdr[2], __lladdr[3],
__lladdr[4], __lladdr[5]);
DEBUG(daemon_log(LOG_DEBUG, "Using pcap filter '%s'", filter));
err = pcap_compile(pp, &bpf, filter, 1, 0);
avahi_free(filter);
if (err == -1) {
daemon_log(LOG_ERR, "pcap_compile: %s", pcap_geterr(pp));
pcap_close(pp);
return (-1);
}
err = pcap_setfilter(pp, &bpf);
if (err == -1) {
daemon_log(LOG_ERR, "pcap_setfilter: %s", pcap_geterr(pp));
pcap_close(pp);
return (-1);
}
pcap_freecode(&bpf);
/* Stash pcap-specific context away. */
memcpy(hw_address, __lladdr, ETHER_ADDRLEN);
__pp = pp;
return (fd);
}
static void close_socket(int fd AVAHI_GCC_UNUSED) {
assert(__pp != NULL);
pcap_close(__pp);
__pp = NULL;
}
/*
* We trick avahi into allocating sizeof(packet) + sizeof(ether_header),
* and prepend the required ethernet header information before sending.
*/
static int send_packet(int fd AVAHI_GCC_UNUSED, int iface AVAHI_GCC_UNUSED, ArpPacket *packet, size_t packet_len) {
struct ether_header *eh;
assert(__pp != NULL);
assert(packet != NULL);
eh = (struct ether_header *)packet->ether_header;
memset(eh->ether_dhost, 0xFF, ETHER_ADDRLEN);
memcpy(eh->ether_shost, __lladdr, ETHER_ADDRLEN);
eh->ether_type = htons(0x0806);
return (pcap_inject(__pp, (void *)eh, packet_len + sizeof(*eh)));
}
static int recv_packet(int fd AVAHI_GCC_UNUSED, ArpPacket **packet, size_t *packet_len) {
struct pcap_pkthdr *ph;
u_char *pd;
ArpPacket *ap;
int err;
int retval;
assert(__pp != NULL);
assert(packet != NULL);
assert(packet_len != NULL);
*packet = NULL;
*packet_len = 0;
retval = -1;
err = pcap_next_ex(__pp, &ph, (const u_char **)&pd);
if (err == 1 && ph->caplen <= ph->len) {
ap = packet_new(ph->caplen);
memcpy(ap->ether_header, pd, ph->caplen);
*packet = ap;
*packet_len = (ph->caplen - sizeof(struct ether_header));
retval = 0;
} else if (err >= 0) {
/*
* err == 1: Just drop bogus packets (>1500 for an arp packet!?)
* on the floor.
*
* err == 0: We might have had traffic on the pcap fd that
* didn't match the filter, in which case we'll get 0 packets.
*/
retval = 0;
} else
daemon_log(LOG_ERR, "pcap_next_ex(%d): %s",
err, pcap_geterr(__pp));
return (retval);
}
#endif /* __linux__ */
int is_ll_address(uint32_t addr) {
return
((ntohl(addr) & IPV4LL_NETMASK) == IPV4LL_NETWORK) &&
((ntohl(addr) & 0x0000FF00) != 0x0000) &&
((ntohl(addr) & 0x0000FF00) != 0xFF00);
}
static struct timeval *elapse_time(struct timeval *tv, unsigned msec, unsigned jitter) {
assert(tv);
gettimeofday(tv, NULL);
if (msec)
avahi_timeval_add(tv, (AvahiUsec) msec*1000);
if (jitter)
avahi_timeval_add(tv, (AvahiUsec) (jitter*1000.0*rand()/(RAND_MAX+1.0)));
return tv;
}
static FILE* fork_dispatcher(void) {
FILE *ret;
int fds[2];
pid_t pid;
if (pipe(fds) < 0) {
daemon_log(LOG_ERR, "pipe() failed: %s", strerror(errno));
goto fail;
}
if ((pid = fork()) < 0)
goto fail;
else if (pid == 0) {
FILE *f = NULL;
int r = 1;
/* Please note that the signal pipe is not closed at this
* point, signals will thus be dispatched in the main
* process. */
daemon_retval_done();
avahi_set_proc_title(argv0, "%s: [%s] callout dispatcher", argv0, interface_name);
close(fds[1]);
if (!(f = fdopen(fds[0], "r"))) {
daemon_log(LOG_ERR, "fdopen() failed: %s", strerror(errno));
goto dispatcher_fail;
}
for (;;) {
CalloutEventInfo info;
char name[IFNAMSIZ], buf[64];
int k;
if (fread(&info, sizeof(info), 1, f) != 1) {
if (feof(f))
break;
daemon_log(LOG_ERR, "fread() failed: %s", strerror(errno));
goto dispatcher_fail;
}
assert(info.event <= CALLOUT_MAX);
if (!if_indextoname(info.ifindex, name)) {
daemon_log(LOG_ERR, "if_indextoname() failed: %s", strerror(errno));
continue;
}
if (daemon_exec("/", &k,
action_script, action_script,
callout_event_table[info.event],
name,
inet_ntop(AF_INET, &info.address, buf, sizeof(buf)), NULL) < 0) {
daemon_log(LOG_ERR, "Failed to run script: %s", strerror(errno));
continue;
}
if (k != 0)
daemon_log(LOG_WARNING, "Script execution failed with return value %i", k);
}
r = 0;
dispatcher_fail:
if (f)
fclose(f);
#ifdef HAVE_CHROOT
/* If the main process is trapped inside a chroot() we have to
* remove the PID file for it */
if (!no_chroot && wrote_pid_file)
daemon_pid_file_remove();
#endif
_exit(r);
}
/* parent */
close(fds[0]);
fds[0] = -1;
if (!(ret = fdopen(fds[1], "w"))) {
daemon_log(LOG_ERR, "fdopen() failed: %s", strerror(errno));
goto fail;
}
return ret;
fail:
if (fds[0] >= 0)
close(fds[0]);
if (fds[1] >= 0)
close(fds[1]);
return NULL;
}
static int do_callout(FILE *f, CalloutEvent event, int iface, uint32_t addr) {
CalloutEventInfo info;
char buf[64], ifname[IFNAMSIZ];
daemon_log(LOG_INFO, "Callout %s, address %s on interface %s",
callout_event_table[event],
inet_ntop(AF_INET, &addr, buf, sizeof(buf)),
if_indextoname(iface, ifname));
info.event = event;
info.ifindex = iface;
info.address = addr;
if (fwrite(&info, sizeof(info), 1, f) != 1 || fflush(f) != 0) {
daemon_log(LOG_ERR, "Failed to write callout event: %s", strerror(errno));
return -1;
}
return 0;
}
#define set_env(key, value) putenv(avahi_strdup_printf("%s=%s", (key), (value)))
static int drop_privs(void) {
struct passwd *pw;
struct group * gr;
int r;
mode_t u;
pw = NULL;
gr = NULL;
/* Get user/group ID */
if (!no_drop_root) {
if (!(pw = getpwnam(AVAHI_AUTOIPD_USER))) {
daemon_log(LOG_ERR, "Failed to find user '"AVAHI_AUTOIPD_USER"'.");
return -1;
}
if (!(gr = getgrnam(AVAHI_AUTOIPD_GROUP))) {
daemon_log(LOG_ERR, "Failed to find group '"AVAHI_AUTOIPD_GROUP"'.");
return -1;
}
daemon_log(LOG_INFO, "Found user '"AVAHI_AUTOIPD_USER"' (UID %lu) and group '"AVAHI_AUTOIPD_GROUP"' (GID %lu).", (unsigned long) pw->pw_uid, (unsigned long) gr->gr_gid);
}
/* Create directory */
u = umask(0000);
r = mkdir(AVAHI_IPDATA_DIR, 0755);
umask(u);
if (r < 0 && errno != EEXIST) {
daemon_log(LOG_ERR, "mkdir(\""AVAHI_IPDATA_DIR"\"): %s", strerror(errno));
return -1;
}
/* Convey working directory */
if (!no_drop_root) {
struct stat st;
chown(AVAHI_IPDATA_DIR, pw->pw_uid, gr->gr_gid);
if (stat(AVAHI_IPDATA_DIR, &st) < 0) {
daemon_log(LOG_ERR, "stat(): %s\n", strerror(errno));
return -1;
}
if (!S_ISDIR(st.st_mode) || st.st_uid != pw->pw_uid || st.st_gid != gr->gr_gid) {
daemon_log(LOG_ERR, "Failed to create runtime directory "AVAHI_IPDATA_DIR".");
return -1;
}
}
#ifdef HAVE_CHROOT
if (!no_chroot) {
if (chroot(AVAHI_IPDATA_DIR) < 0) {
daemon_log(LOG_ERR, "Failed to chroot(): %s", strerror(errno));
return -1;
}
daemon_log(LOG_INFO, "Successfully called chroot().");
chdir("/");
/* Since we are now trapped inside a chroot we cannot remove
* the pid file anymore, the helper process will do that for us. */
wrote_pid_file = 0;
}
#endif
if (!no_drop_root) {
if (initgroups(AVAHI_AUTOIPD_USER, gr->gr_gid) != 0) {
daemon_log(LOG_ERR, "Failed to change group list: %s", strerror(errno));
return -1;
}
#if defined(HAVE_SETRESGID)
r = setresgid(gr->gr_gid, gr->gr_gid, gr->gr_gid);
#elif defined(HAVE_SETEGID)
if ((r = setgid(gr->gr_gid)) >= 0)
r = setegid(gr->gr_gid);
#elif defined(HAVE_SETREGID)
r = setregid(gr->gr_gid, gr->gr_gid);
#else
#error "No API to drop privileges"
#endif
if (r < 0) {
daemon_log(LOG_ERR, "Failed to change GID: %s", strerror(errno));
return -1;
}
#if defined(HAVE_SETRESUID)
r = setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid);
#elif defined(HAVE_SETEUID)
if ((r = setuid(pw->pw_uid)) >= 0)
r = seteuid(pw->pw_uid);
#elif defined(HAVE_SETREUID)
r = setreuid(pw->pw_uid, pw->pw_uid);
#else
#error "No API to drop privileges"
#endif
if (r < 0) {
daemon_log(LOG_ERR, "Failed to change UID: %s", strerror(errno));
return -1;
}
set_env("USER", pw->pw_name);
set_env("LOGNAME", pw->pw_name);
set_env("HOME", pw->pw_dir);
daemon_log(LOG_INFO, "Successfully dropped root privileges.");
}
return 0;
}
static int loop(int iface, uint32_t addr) {
enum {
FD_ARP,
FD_IFACE,
FD_SIGNAL,
FD_MAX
};
int fd = -1, ret = -1;
struct timeval next_wakeup;
int next_wakeup_valid = 0;
char buf[64];
ArpPacket *in_packet = NULL;
size_t in_packet_len = 0;
ArpPacket *out_packet = NULL;
size_t out_packet_len;
uint8_t hw_address[ETHER_ADDRLEN];
struct pollfd pollfds[FD_MAX];
int iface_fd = -1;
Event event = EVENT_NULL;
int retval_sent = !daemonize;
State st;
FILE *dispatcher = NULL;
char *address_fn = NULL;
const char *p;
daemon_signal_init(SIGINT, SIGTERM, SIGCHLD, SIGHUP, 0);
if (!(dispatcher = fork_dispatcher()))
goto fail;
if ((fd = open_socket(iface, hw_address)) < 0)
goto fail;
if ((iface_fd = iface_init(iface)) < 0)
goto fail;
if (drop_privs() < 0)
goto fail;
if (force_bind)
st = STATE_START;
else if (iface_get_initial_state(&st) < 0)
goto fail;
#ifdef HAVE_CHROOT
if (!no_chroot)
p = "";
else
#endif
p = AVAHI_IPDATA_DIR;
address_fn = avahi_strdup_printf(
"%s/%02x:%02x:%02x:%02x:%02x:%02x", p,
hw_address[0], hw_address[1],
hw_address[2], hw_address[3],
hw_address[4], hw_address[5]);
if (!addr)
load_address(address_fn, &addr);
if (addr && !is_ll_address(addr)) {
daemon_log(LOG_WARNING, "Requested address %s is not from IPv4LL range 169.254/16 or a reserved address, ignoring.", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
addr = 0;
}
if (!addr) {
int i;
uint32_t a = 1;
for (i = 0; i < ETHER_ADDRLEN; i++)
a += hw_address[i]*i;
a = (a % 0xFE00) + 0x0100;
addr = htonl(IPV4LL_NETWORK | (uint32_t) a);
}
assert(is_ll_address(addr));
set_state(st, 1, addr);
daemon_log(LOG_INFO, "Starting with address %s", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
if (state == STATE_SLEEPING)
daemon_log(LOG_INFO, "Routable address already assigned, sleeping.");
if (!retval_sent && (!wait_for_address || state == STATE_SLEEPING)) {
daemon_retval_send(0);
retval_sent = 1;
}
memset(pollfds, 0, sizeof(pollfds));
pollfds[FD_ARP].fd = fd;
pollfds[FD_ARP].events = POLLIN;
pollfds[FD_IFACE].fd = iface_fd;
pollfds[FD_IFACE].events = POLLIN;
pollfds[FD_SIGNAL].fd = daemon_signal_fd();
pollfds[FD_SIGNAL].events = POLLIN;
for (;;) {
int r, timeout;
AvahiUsec usec;
if (state == STATE_START) {
/* First, wait a random time */
set_state(STATE_WAITING_PROBE, 1, addr);
elapse_time(&next_wakeup, 0, PROBE_WAIT*1000);
next_wakeup_valid = 1;
} else if ((state == STATE_WAITING_PROBE && event == EVENT_TIMEOUT) ||
(state == STATE_PROBING && event == EVENT_TIMEOUT && n_iteration < PROBE_NUM-2)) {
/* Send a probe */
out_packet = packet_new_probe(addr, hw_address, &out_packet_len);
set_state(STATE_PROBING, 0, addr);
elapse_time(&next_wakeup, PROBE_MIN*1000, (PROBE_MAX-PROBE_MIN)*1000);
next_wakeup_valid = 1;
} else if (state == STATE_PROBING && event == EVENT_TIMEOUT && n_iteration >= PROBE_NUM-2) {
/* Send the last probe */
out_packet = packet_new_probe(addr, hw_address, &out_packet_len);
set_state(STATE_WAITING_ANNOUNCE, 1, addr);
elapse_time(&next_wakeup, ANNOUNCE_WAIT*1000, 0);
next_wakeup_valid = 1;
} else if ((state == STATE_WAITING_ANNOUNCE && event == EVENT_TIMEOUT) ||
(state == STATE_ANNOUNCING && event == EVENT_TIMEOUT && n_iteration < ANNOUNCE_NUM-1)) {
/* Send announcement packet */
out_packet = packet_new_announcement(addr, hw_address, &out_packet_len);
set_state(STATE_ANNOUNCING, 0, addr);
elapse_time(&next_wakeup, ANNOUNCE_INTERVAL*1000, 0);
next_wakeup_valid = 1;
if (n_iteration == 0) {
if (do_callout(dispatcher, CALLOUT_BIND, iface, addr) < 0)
goto fail;
n_conflict = 0;
}
} else if ((state == STATE_ANNOUNCING && event == EVENT_TIMEOUT && n_iteration >= ANNOUNCE_NUM-1)) {
daemon_log(LOG_INFO, "Successfully claimed IP address %s", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
set_state(STATE_RUNNING, 0, addr);
next_wakeup_valid = 0;
save_address(address_fn, addr);
if (!retval_sent) {
daemon_retval_send(0);
retval_sent = 1;
}
} else if (event == EVENT_PACKET) {
ArpPacketInfo info;
assert(in_packet);
if (packet_parse(in_packet, in_packet_len, &info) < 0)
daemon_log(LOG_WARNING, "Failed to parse incoming ARP packet.");
else {
int conflict = 0;
if (info.sender_ip_address == addr) {
if (memcmp(hw_address, info.sender_hw_address, ETHER_ADDRLEN)) {
/* Normal conflict */
conflict = 1;
daemon_log(LOG_INFO, "Received conflicting normal ARP packet.");
} else
daemon_log(LOG_DEBUG, "Received ARP packet back on source interface. Ignoring.");
} else if (state == STATE_WAITING_PROBE || state == STATE_PROBING || state == STATE_WAITING_ANNOUNCE) {
/* Probe conflict */
conflict = info.target_ip_address == addr && memcmp(hw_address, info.sender_hw_address, ETHER_ADDRLEN);
if (conflict)
daemon_log(LOG_INFO, "Received conflicting probe ARP packet.");
}
if (conflict) {
if (state == STATE_RUNNING || state == STATE_ANNOUNCING)
if (do_callout(dispatcher, CALLOUT_CONFLICT, iface, addr) < 0)
goto fail;
/* Pick a new address */
addr = pick_addr(addr);
daemon_log(LOG_INFO, "Trying address %s", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
n_conflict++;
set_state(STATE_WAITING_PROBE, 1, addr);
if (n_conflict >= MAX_CONFLICTS) {
daemon_log(LOG_WARNING, "Got too many conflicts, rate limiting new probes.");
elapse_time(&next_wakeup, RATE_LIMIT_INTERVAL*1000, PROBE_WAIT*1000);
} else
elapse_time(&next_wakeup, 0, PROBE_WAIT*1000);
next_wakeup_valid = 1;
} else
DEBUG(daemon_log(LOG_DEBUG, "Ignoring irrelevant ARP packet."));
}
} else if (event == EVENT_ROUTABLE_ADDR_CONFIGURED && !force_bind) {
daemon_log(LOG_INFO, "A routable address has been configured.");
if (state == STATE_RUNNING || state == STATE_ANNOUNCING)
if (do_callout(dispatcher, CALLOUT_UNBIND, iface, addr) < 0)
goto fail;
if (!retval_sent) {
daemon_retval_send(0);
retval_sent = 1;
}
set_state(STATE_SLEEPING, 1, addr);
next_wakeup_valid = 0;
} else if (event == EVENT_ROUTABLE_ADDR_UNCONFIGURED && state == STATE_SLEEPING && !force_bind) {
daemon_log(LOG_INFO, "No longer a routable address configured, restarting probe process.");
set_state(STATE_WAITING_PROBE, 1, addr);
elapse_time(&next_wakeup, 0, PROBE_WAIT*1000);
next_wakeup_valid = 1;
} else if (event == EVENT_REFRESH_REQUEST && state == STATE_RUNNING) {
/* The user requested a reannouncing of the address by a SIGHUP */
daemon_log(LOG_INFO, "Reannouncing address.");
/* Send announcement packet */
out_packet = packet_new_announcement(addr, hw_address, &out_packet_len);
set_state(STATE_ANNOUNCING, 1, addr);
elapse_time(&next_wakeup, ANNOUNCE_INTERVAL*1000, 0);
next_wakeup_valid = 1;
}
if (out_packet) {
DEBUG(daemon_log(LOG_DEBUG, "sending..."));
if (send_packet(fd, iface, out_packet, out_packet_len) < 0)
goto fail;
avahi_free(out_packet);
out_packet = NULL;
}
if (in_packet) {
avahi_free(in_packet);
in_packet = NULL;
}
event = EVENT_NULL;
timeout = -1;
if (next_wakeup_valid) {
usec = avahi_age(&next_wakeup);
timeout = usec < 0 ? (int) (-usec/1000) : 0;
}
DEBUG(daemon_log(LOG_DEBUG, "sleeping %ims", timeout));
while ((r = poll(pollfds, FD_MAX, timeout)) < 0 && errno == EINTR)
;
if (r < 0) {
daemon_log(LOG_ERR, "poll() failed: %s", strerror(r));
goto fail;
} else if (r == 0) {
event = EVENT_TIMEOUT;
next_wakeup_valid = 0;
} else {
if (pollfds[FD_ARP].revents) {
if (pollfds[FD_ARP].revents == POLLERR) {
/* The interface is probably down, let's recreate our socket */
close_socket(fd);
if ((fd = open_socket(iface, hw_address)) < 0)
goto fail;
pollfds[FD_ARP].fd = fd;
} else {
assert(pollfds[FD_ARP].revents == POLLIN);
if (recv_packet(fd, &in_packet, &in_packet_len) < 0)
goto fail;
if (in_packet)
event = EVENT_PACKET;
}
}
if (event == EVENT_NULL &&
pollfds[FD_IFACE].revents) {
assert(pollfds[FD_IFACE].revents == POLLIN);
if (iface_process(&event) < 0)
goto fail;
}
if (event == EVENT_NULL &&
pollfds[FD_SIGNAL].revents) {
int sig;
assert(pollfds[FD_SIGNAL].revents == POLLIN);
if ((sig = daemon_signal_next()) <= 0) {
daemon_log(LOG_ERR, "daemon_signal_next() failed");
goto fail;
}
switch(sig) {
case SIGINT:
case SIGTERM:
daemon_log(LOG_INFO, "Got %s, quitting.", sig == SIGINT ? "SIGINT" : "SIGTERM");
ret = 0;
goto fail;
case SIGCHLD:
waitpid(-1, NULL, WNOHANG);
break;
case SIGHUP:
event = EVENT_REFRESH_REQUEST;
break;
}
}
}
}
ret = 0;
fail:
if (state == STATE_RUNNING || state == STATE_ANNOUNCING)
do_callout(dispatcher, CALLOUT_STOP, iface, addr);
avahi_free(out_packet);
avahi_free(in_packet);
if (fd >= 0)
close_socket(fd);
if (iface_fd >= 0)
iface_done();
if (daemonize && !retval_sent)
daemon_retval_send(ret);
if (dispatcher)
fclose(dispatcher);
if (address_fn)
avahi_free(address_fn);
return ret;
}
static void help(FILE *f, const char *a0) {
fprintf(f,
"%s [options] INTERFACE\n"
" -h --help Show this help\n"
" -D --daemonize Daemonize after startup\n"
" -s --syslog Write log messages to syslog(3) instead of STDERR\n"
" -k --kill Kill a running daemon\n"
" -r --refresh Request a running daemon refresh its IP address\n"
" -c --check Return 0 if a daemon is already running\n"
" -V --version Show version\n"
" -S --start=ADDRESS Start with this address from the IPv4LL range\n"
" 169.254.0.0/16\n"
" -t --script=script Action script to run (defaults to\n"
" "AVAHI_IPCONF_SCRIPT")\n"
" -w --wait Wait until an address has been acquired before\n"
" daemonizing\n"
" --force-bind Assign an IPv4LL address even if a routable address\n"
" is already assigned\n"
" --no-drop-root Don't drop privileges\n"
#ifdef HAVE_CHROOT
" --no-chroot Don't chroot()\n"
#endif
" --no-proc-title Don't modify process title\n"
" --debug Increase verbosity\n",
a0);
}
static int parse_command_line(int argc, char *argv[]) {
int c;
enum {
OPTION_NO_PROC_TITLE = 256,
OPTION_FORCE_BIND,
OPTION_DEBUG,
OPTION_NO_DROP_ROOT,
#ifdef HAVE_CHROOT
OPTION_NO_CHROOT
#endif
};
static const struct option long_options[] = {
{ "help", no_argument, NULL, 'h' },
{ "daemonize", no_argument, NULL, 'D' },
{ "syslog", no_argument, NULL, 's' },
{ "kill", no_argument, NULL, 'k' },
{ "refresh", no_argument, NULL, 'r' },
{ "check", no_argument, NULL, 'c' },
{ "version", no_argument, NULL, 'V' },
{ "start", required_argument, NULL, 'S' },
{ "script", required_argument, NULL, 't' },
{ "wait", no_argument, NULL, 'w' },
{ "force-bind", no_argument, NULL, OPTION_FORCE_BIND },
{ "no-drop-root", no_argument, NULL, OPTION_NO_DROP_ROOT },
#ifdef HAVE_CHROOT
{ "no-chroot", no_argument, NULL, OPTION_NO_CHROOT },
#endif
{ "no-proc-title", no_argument, NULL, OPTION_NO_PROC_TITLE },
{ "debug", no_argument, NULL, OPTION_DEBUG },
{ NULL, 0, NULL, 0 }
};
while ((c = getopt_long(argc, argv, "hDskrcVS:t:w", long_options, NULL)) >= 0) {
switch(c) {
case 's':
use_syslog = 1;
break;
case 'h':
command = DAEMON_HELP;
break;
case 'D':
daemonize = 1;
break;
case 'k':
command = DAEMON_KILL;
break;
case 'V':
command = DAEMON_VERSION;
break;
case 'r':
command = DAEMON_REFRESH;
break;
case 'c':
command = DAEMON_CHECK;
break;
case 'S':
if ((start_address = inet_addr(optarg)) == (uint32_t) -1) {
fprintf(stderr, "Failed to parse IP address '%s'.", optarg);
return -1;
}
break;
case 't':
avahi_free(action_script);
action_script = avahi_strdup(optarg);
break;
case 'w':
wait_for_address = 1;
break;
case OPTION_NO_PROC_TITLE:
modify_proc_title = 0;
break;
case OPTION_DEBUG:
debug = 1;
break;
case OPTION_FORCE_BIND:
force_bind = 1;
break;
case OPTION_NO_DROP_ROOT:
no_drop_root = 1;
break;
#ifdef HAVE_CHROOT
case OPTION_NO_CHROOT:
no_chroot = 1;
break;
#endif
default:
return -1;
}
}
if (command == DAEMON_RUN ||
command == DAEMON_KILL ||
command == DAEMON_REFRESH ||
command == DAEMON_CHECK) {
if (optind >= argc) {
fprintf(stderr, "Missing interface name.\n");
return -1;
}
interface_name = avahi_strdup(argv[optind++]);
}
if (optind != argc) {
fprintf(stderr, "Too many arguments\n");
return -1;
}
if (!action_script)
action_script = avahi_strdup(AVAHI_IPCONF_SCRIPT);
return 0;
}
static const char* pid_file_proc(void) {
return pid_file_name;
}
int main(int argc, char*argv[]) {
int r = 1;
char *log_ident = NULL;
signal(SIGPIPE, SIG_IGN);
if ((argv0 = strrchr(argv[0], '/')))
argv0 = avahi_strdup(argv0 + 1);
else
argv0 = avahi_strdup(argv[0]);
daemon_log_ident = argv0;
if (parse_command_line(argc, argv) < 0)
goto finish;
if (modify_proc_title)
avahi_init_proc_title(argc, argv);
daemon_log_ident = log_ident = avahi_strdup_printf("%s(%s)", argv0, interface_name);
daemon_pid_file_proc = pid_file_proc;
pid_file_name = avahi_strdup_printf(AVAHI_RUNTIME_DIR"/avahi-autoipd.%s.pid", interface_name);
if (command == DAEMON_RUN) {
pid_t pid;
int ifindex;
init_rand_seed();
if ((ifindex = if_nametoindex(interface_name)) <= 0) {
daemon_log(LOG_ERR, "Failed to get index for interface name '%s': %s", interface_name, strerror(errno));
goto finish;
}
if (getuid() != 0) {
daemon_log(LOG_ERR, "This program is intended to be run as root.");
goto finish;
}
if ((pid = daemon_pid_file_is_running()) >= 0) {
daemon_log(LOG_ERR, "Daemon already running on PID %u", pid);
goto finish;
}
if (daemonize) {
daemon_retval_init();
if ((pid = daemon_fork()) < 0)
goto finish;
else if (pid != 0) {
int ret;
/** Parent **/
if ((ret = daemon_retval_wait(20)) < 0) {
daemon_log(LOG_ERR, "Could not receive return value from daemon process.");
goto finish;
}
r = ret;
goto finish;
}
/* Child */
}
if (use_syslog || daemonize)
daemon_log_use = DAEMON_LOG_SYSLOG;
chdir("/");
if (daemon_pid_file_create() < 0) {
daemon_log(LOG_ERR, "Failed to create PID file: %s", strerror(errno));
if (daemonize)
daemon_retval_send(1);
goto finish;
} else
wrote_pid_file = 1;
avahi_set_proc_title(argv0, "%s: [%s] starting up", argv0, interface_name);
if (loop(ifindex, start_address) < 0)
goto finish;
r = 0;
} else if (command == DAEMON_HELP) {
help(stdout, argv0);
r = 0;
} else if (command == DAEMON_VERSION) {
printf("%s "PACKAGE_VERSION"\n", argv0);
r = 0;
} else if (command == DAEMON_KILL) {
if (daemon_pid_file_kill_wait(SIGTERM, 5) < 0) {
daemon_log(LOG_WARNING, "Failed to kill daemon: %s", strerror(errno));
goto finish;
}
r = 0;
} else if (command == DAEMON_REFRESH) {
if (daemon_pid_file_kill(SIGHUP) < 0) {
daemon_log(LOG_WARNING, "Failed to kill daemon: %s", strerror(errno));
goto finish;
}
r = 0;
} else if (command == DAEMON_CHECK)
r = (daemon_pid_file_is_running() >= 0) ? 0 : 1;
finish:
if (daemonize)
daemon_retval_done();
if (wrote_pid_file)
daemon_pid_file_remove();
avahi_free(log_ident);
avahi_free(pid_file_name);
avahi_free(argv0);
avahi_free(interface_name);
avahi_free(action_script);
return r;
}