static void answer(struct worker_info *w)
{
struct adns_answer a;
enum helper_exit_status r = read_pipe(w->afd, (unsigned char *)&a,
offsetof(struct adns_answer,
ans), sizeof(a));
if (r == HES_OK) {
/* unexpected EOF */
syslog(LOG_ERR, "unexpected EOF from worker");
exit(HES_IO_ERROR_IN);
} else if (r != HES_CONTINUE) {
exit(r);
} else if (a.amagic != ADNS_A_MAGIC) {
syslog(LOG_ERR, "Input from worker error: bad magic");
exit(HES_BAD_MAGIC);
} else if (a.continuation != w->continuation) {
/* answer doesn't match query */
syslog(LOG_ERR,
"Input from worker error: continuation mismatch");
exit(HES_SYNC);
} else {
/* pass the answer on to Pluto */
enum helper_exit_status rs =
write_pipe(PLUTO_AFD, (const unsigned char *) &a);
if (rs != HES_CONTINUE)
exit(rs);
w->busy = FALSE;
forward_query(w);
}
}
static void query(void)
{
struct query_list *q = free_queries;
enum helper_exit_status r;
/* find an unused queue entry */
if (q == NULL) {
q = malloc(sizeof(*q));
if (q == NULL) {
syslog(LOG_ERR, "malloc(3) failed");
exit(HES_MALLOC);
}
} else {
free_queries = q->next;
}
r = read_pipe(PLUTO_QFD, (unsigned char *)&q->aq,
sizeof(q->aq), sizeof(q->aq));
if (r == HES_OK) {
/* EOF: we're done, except for unanswered queries */
struct worker_info *w;
eof_from_pluto = TRUE;
q->next = free_queries;
free_queries = q;
/* Send bye-bye to unbusy processes.
* Note that if there are queued queries, there won't be
* any non-busy workers.
*/
for (w = wi; w != wi_roof; w++)
if (!w->busy)
send_eof(w);
} else if (r != HES_CONTINUE) {
exit(r);
} else if (q->aq.qmagic != ADNS_Q_MAGIC) {
syslog(LOG_ERR, "error in query from Pluto: bad magic");
exit(HES_BAD_MAGIC);
} else {
struct worker_info *w;
/* got a query */
/* add it to FIFO */
q->next = NULL;
if (oldest_query == NULL)
oldest_query = q;
else
newest_query->next = q;
newest_query = q;
/* See if any worker available */
for (w = wi;; w++) {
if (w == wi_roof) {
/* no free worker */
if (w == wi + MAX_WORKERS)
break; /* no more to be created */
/* make a new one */
if (!spawn_worker())
break; /* cannot create one at this time */
}
if (!w->busy) {
/* assign first to free worker */
forward_query(w);
break;
}
}
}
return;
}
int main (int argc, char **argv)
{
char *int_err_string;
int cachesize = CACHESIZ;
int port = NAMESERVER_PORT;
int query_port = 0;
unsigned long local_ttl = 0;
int logged_lease = 0, first_loop = 1;
unsigned int options;
char *runfile = RUNFILE;
time_t resolv_changed = 0;
time_t now, last = 0;
time_t lease_file_change = 0;
ino_t lease_file_inode = (ino_t)0;
struct irec *iface, *interfaces = NULL;
char *mxname = NULL;
char *mxtarget = NULL;
char *lease_file = NULL;
char *addn_hosts = NULL;
char *domain_suffix = NULL;
char *username = CHUSER;
char *groupname = CHGRP;
struct iname *if_names = NULL;
struct iname *if_addrs = NULL;
struct iname *if_except = NULL;
struct iname *if_tmp;
struct server *serv_addrs = NULL;
char *dnamebuff, *packet;
struct server *servers, *last_server;
struct resolvc default_resolv = { NULL, 1, 0, RESOLVFILE };
struct resolvc *resolv = &default_resolv;
struct bogus_addr *bogus_addr = NULL;
struct serverfd *serverfdp, *sfds = NULL;
sighup = 1; /* init cache the first time through */
sigusr1 = 0; /* but don't dump */
sigusr2 = 0; /* or rescan interfaces */
signal(SIGUSR1, sig_handler);
signal(SIGUSR2, sig_handler);
signal(SIGHUP, sig_handler);
/* These get allocated here to avoid overflowing the small stack
on embedded systems. dnamebuff is big enough to hold one
maximal sixed domain name and gets passed into all the processing
code. We manage to get away with one buffer. */
dnamebuff = safe_malloc(MAXDNAME);
/* Size: we check after adding each record, so there must be
memory for the largest packet, and the largest record */
packet = safe_malloc(PACKETSZ+MAXDNAME+RRFIXEDSZ);
options = read_opts(argc, argv, dnamebuff, &resolv, &mxname, &mxtarget, &lease_file,
&username, &groupname, &domain_suffix, &runfile,
&if_names, &if_addrs, &if_except, &bogus_addr,
&serv_addrs, &cachesize, &port, &query_port, &local_ttl, &addn_hosts);
int_err_string = enumerate_interfaces(&interfaces, if_names, if_addrs, if_except, port);
if (int_err_string)
die(int_err_string, NULL);
for (if_tmp = if_names; if_tmp; if_tmp = if_tmp->next)
if (if_tmp->name && !if_tmp->found)
die("unknown interface %s", if_tmp->name);
for (if_tmp = if_addrs; if_tmp; if_tmp = if_tmp->next)
if (!if_tmp->found)
{
char addrbuff[ADDRSTRLEN];
#ifdef HAVE_IPV6
if (if_tmp->addr.sa.sa_family == AF_INET)
inet_ntop(AF_INET, &if_tmp->addr.in.sin_addr,
addrbuff, ADDRSTRLEN);
else
inet_ntop(AF_INET6, &if_tmp->addr.in6.sin6_addr,
addrbuff, ADDRSTRLEN);
#else
strcpy(addrbuff, inet_ntoa(if_tmp->addr.in.sin_addr));
#endif
die("no interface with address %s", addrbuff);
}
forward_init(1);
cache_init(cachesize, options & OPT_LOG);
setbuf(stdout, NULL);
if (!(options & OPT_DEBUG))
{
FILE *pidfile;
struct passwd *ent_pw;
int i;
/* The following code "daemonizes" the process.
See Stevens section 12.4 */
#ifndef NO_FORK
if (fork() != 0 )
exit(0);
setsid();
if (fork() != 0)
exit(0);
#endif
chdir("/");
umask(022); /* make pidfile 0644 */
/* write pidfile _after_ forking ! */
if (runfile && (pidfile = fopen(runfile, "w")))
{
fprintf(pidfile, "%d\n", (int) getpid());
fclose(pidfile);
}
umask(0);
for (i=0; i<64; i++)
{
for (iface = interfaces; iface; iface = iface->next)
if (iface->fd == i)
break;
if (iface)
continue;
close(i);
}
/* Change uid and gid for security */
if (username && (ent_pw = getpwnam(username)))
{
gid_t dummy;
struct group *gp;
/* remove all supplimentary groups */
setgroups(0, &dummy);
/* change group for /etc/ppp/resolv.conf
otherwise get the group for "nobody" */
if ((groupname && (gp = getgrnam(groupname))) ||
(gp = getgrgid(ent_pw->pw_gid)))
setgid(gp->gr_gid);
/* finally drop root */
setuid(ent_pw->pw_uid);
}
}
openlog("dnsmasq",
DNSMASQ_LOG_OPT(options & OPT_DEBUG),
DNSMASQ_LOG_FAC(options & OPT_DEBUG));
if (cachesize)
syslog(LOG_INFO, "started, version %s cachesize %d", VERSION, cachesize);
else
syslog(LOG_INFO, "started, version %s cache disabled", VERSION);
if (options & OPT_LOCALMX)
syslog(LOG_INFO, "serving MX record for local hosts target %s", mxtarget);
else if (mxname)
syslog(LOG_INFO, "serving MX record for mailhost %s target %s",
mxname, mxtarget);
if (getuid() == 0 || geteuid() == 0)
syslog(LOG_WARNING, "failed to drop root privs");
servers = last_server = check_servers(serv_addrs, interfaces, &sfds);
while (1)
{
int ready, maxfd = 0;
fd_set rset;
HEADER *header;
struct stat statbuf;
if (first_loop)
/* do init stuff only first time round. */
{
first_loop = 0;
ready = 0;
}
else
{
FD_ZERO(&rset);
for (serverfdp = sfds; serverfdp; serverfdp = serverfdp->next)
{
FD_SET(serverfdp->fd, &rset);
if (serverfdp->fd > maxfd)
maxfd = serverfdp->fd;
}
for (iface = interfaces; iface; iface = iface->next)
{
FD_SET(iface->fd, &rset);
if (iface->fd > maxfd)
maxfd = iface->fd;
}
ready = select(maxfd+1, &rset, NULL, NULL, NULL);
if (ready == -1)
{
if (errno == EINTR)
ready = 0; /* do signal handlers */
else
continue;
}
}
if (sighup)
{
signal(SIGHUP, SIG_IGN);
cache_reload(options, dnamebuff, domain_suffix, addn_hosts);
if (resolv && (options & OPT_NO_POLL))
servers = last_server =
check_servers(reload_servers(resolv->name, dnamebuff, servers, query_port),
interfaces, &sfds);
sighup = 0;
signal(SIGHUP, sig_handler);
}
if (sigusr1)
{
signal(SIGUSR1, SIG_IGN);
dump_cache(options & (OPT_DEBUG | OPT_LOG), cachesize);
sigusr1 = 0;
signal(SIGUSR1, sig_handler);
}
if (sigusr2)
{
signal(SIGUSR2, SIG_IGN);
if (getuid() != 0 && port <= 1024)
syslog(LOG_ERR, "cannot re-scan interfaces unless --user=root");
else
{
syslog(LOG_INFO, "rescanning network interfaces");
int_err_string = enumerate_interfaces(&interfaces, if_names, if_addrs, if_except, port);
if (int_err_string)
syslog(LOG_ERR, int_err_string, strerror(errno));
}
sigusr2 = 0;
signal(SIGUSR2, sig_handler);
/* may be new file descriptors now, so redo select() */
ready = 0;
}
now = time(NULL);
/* Check for changes to resolv files and DHCP leases file once per second max. */
if (last == 0 || now > last)
{
last = now;
if (!(options & OPT_NO_POLL))
{
struct resolvc *res = resolv, *latest = NULL;
time_t last_change = 0;
/* There may be more than one possible file.
Go through and find the one which changed _last_.
Warn of any which can't be read. */
while (res)
{
if (stat(res->name, &statbuf) == -1)
{
if (!res->logged)
syslog(LOG_WARNING, "failed to access %s: %m", res->name);
res->logged = 1;
}
else
{
res->logged = 0;
if (statbuf.st_mtime > last_change)
{
last_change = statbuf.st_mtime;
latest = res;
}
}
res = res->next;
}
if (latest && last_change > resolv_changed)
{
resolv_changed = last_change;
servers = last_server =
check_servers(reload_servers(latest->name, dnamebuff, servers, query_port),
interfaces, &sfds);
}
}
if (lease_file)
{
syslog(LOG_WARNING, "checking lease file %s", lease_file);
if (stat(lease_file, &statbuf) == -1)
{
if (!logged_lease)
syslog(LOG_WARNING, "failed to access %s: %m", lease_file);
logged_lease = 1;
}
else
{
logged_lease = 0;
if ((statbuf.st_mtime != lease_file_change) ||
(statbuf.st_ino != lease_file_inode))
{
lease_file_change = statbuf.st_mtime;
lease_file_inode = statbuf.st_ino;
load_dhcp(lease_file, domain_suffix, now, dnamebuff);
}
}
}
}
if (ready == 0)
continue; /* no sockets ready */
for (serverfdp = sfds; serverfdp; serverfdp = serverfdp->next)
if (FD_ISSET(serverfdp->fd, &rset))
last_server = reply_query(serverfdp->fd, options, packet, now,
dnamebuff, last_server, bogus_addr);
for (iface = interfaces; iface; iface = iface->next)
{
if (FD_ISSET(iface->fd, &rset))
{
/* request packet, deal with query */
union mysockaddr udpaddr;
socklen_t udplen = sizeof(udpaddr);
int m, n = recvfrom(iface->fd, packet, PACKETSZ, 0, &udpaddr.sa, &udplen);
udpaddr.sa.sa_family = iface->addr.sa.sa_family;
#ifdef HAVE_IPV6
if (udpaddr.sa.sa_family == AF_INET6)
udpaddr.in6.sin6_flowinfo = htonl(0);
#endif
header = (HEADER *)packet;
if (n >= (int)sizeof(HEADER) && !header->qr)
{
if (extract_request(header, (unsigned int)n, dnamebuff))
{
if (udpaddr.sa.sa_family == AF_INET)
log_query(F_QUERY | F_IPV4 | F_FORWARD, dnamebuff,
(struct all_addr *)&udpaddr.in.sin_addr);
#ifdef HAVE_IPV6
else
log_query(F_QUERY | F_IPV6 | F_FORWARD, dnamebuff,
(struct all_addr *)&udpaddr.in6.sin6_addr);
#endif
}
m = answer_request (header, ((char *) header) + PACKETSZ, (unsigned int)n,
mxname, mxtarget, options, now, local_ttl, dnamebuff);
if (m >= 1)
{
/* answered from cache, send reply */
sendto(iface->fd, (char *)header, m, 0,
&udpaddr.sa, sa_len(&udpaddr));
}
else
{
/* cannot answer from cache, send on to real nameserver */
last_server = forward_query(iface->fd, &udpaddr, header, n,
options, dnamebuff, servers,
last_server, now, local_ttl);
}
}
}
}
}
return 0;
}
void receive_query(struct listener *listen, time_t now)
{
HEADER *header = (HEADER *)daemon->packet;
union mysockaddr source_addr;
unsigned short type;
struct all_addr dst_addr;
struct in_addr netmask, dst_addr_4;
size_t m;
ssize_t n;
int if_index = 0;
struct iovec iov[1];
struct msghdr msg;
struct cmsghdr *cmptr;
union {
struct cmsghdr align; /* this ensures alignment */
#ifdef HAVE_IPV6
char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))];
#endif
#if defined(HAVE_LINUX_NETWORK)
char control[CMSG_SPACE(sizeof(struct in_pktinfo))];
#elif defined(IP_RECVDSTADDR)
char control[CMSG_SPACE(sizeof(struct in_addr)) +
CMSG_SPACE(sizeof(struct sockaddr_dl))];
#endif
} control_u;
/* packet buffer overwritten */
daemon->srv_save = NULL;
if (listen->family == AF_INET && (daemon->options & OPT_NOWILD))
{
dst_addr_4 = listen->iface->addr.in.sin_addr;
netmask = listen->iface->netmask;
}
else
{
dst_addr_4.s_addr = 0;
netmask.s_addr = 0;
}
iov[0].iov_base = daemon->packet;
iov[0].iov_len = daemon->edns_pktsz;
msg.msg_control = control_u.control;
msg.msg_controllen = sizeof(control_u);
msg.msg_flags = 0;
msg.msg_name = &source_addr;
msg.msg_namelen = sizeof(source_addr);
msg.msg_iov = iov;
msg.msg_iovlen = 1;
if ((n = recvmsg(listen->fd, &msg, 0)) == -1)
return;
if (n < (int)sizeof(HEADER) ||
(msg.msg_flags & MSG_TRUNC) ||
header->qr)
return;
source_addr.sa.sa_family = listen->family;
#ifdef HAVE_IPV6
if (listen->family == AF_INET6)
source_addr.in6.sin6_flowinfo = 0;
#endif
if (!(daemon->options & OPT_NOWILD))
{
struct ifreq ifr;
if (msg.msg_controllen < sizeof(struct cmsghdr))
return;
#if defined(HAVE_LINUX_NETWORK)
if (listen->family == AF_INET)
for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
if (cmptr->cmsg_level == SOL_IP && cmptr->cmsg_type == IP_PKTINFO)
{
dst_addr_4 = dst_addr.addr.addr4 = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_spec_dst;
if_index = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_ifindex;
}
#elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF)
if (listen->family == AF_INET)
{
for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVDSTADDR)
dst_addr_4 = dst_addr.addr.addr4 = *((struct in_addr *)CMSG_DATA(cmptr));
else if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF)
if_index = ((struct sockaddr_dl *)CMSG_DATA(cmptr))->sdl_index;
}
#endif
#ifdef HAVE_IPV6
if (listen->family == AF_INET6)
{
for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
if (cmptr->cmsg_level == IPV6_LEVEL && cmptr->cmsg_type == IPV6_PKTINFO)
{
dst_addr.addr.addr6 = ((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_addr;
if_index =((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_ifindex;
}
}
#endif
/* enforce available interface configuration */
if (!indextoname(listen->fd, if_index, ifr.ifr_name) ||
!iface_check(listen->family, &dst_addr, ifr.ifr_name, &if_index))
return;
if (listen->family == AF_INET &&
(daemon->options & OPT_LOCALISE) &&
ioctl(listen->fd, SIOCGIFNETMASK, &ifr) == -1)
return;
netmask = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr;
}
if (extract_request(header, (size_t)n, daemon->namebuff, &type))
{
char types[20];
querystr(types, type);
if (listen->family == AF_INET)
log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff,
(struct all_addr *)&source_addr.in.sin_addr, types);
#ifdef HAVE_IPV6
else
log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff,
(struct all_addr *)&source_addr.in6.sin6_addr, types);
#endif
}
m = answer_request (header, ((char *) header) + PACKETSZ, (size_t)n,
dst_addr_4, netmask, now);
if (m >= 1)
{
send_from(listen->fd, daemon->options & OPT_NOWILD, (char *)header,
m, &source_addr, &dst_addr, if_index);
daemon->local_answer++;
}
else if (forward_query(listen->fd, &source_addr, &dst_addr, if_index,
header, (size_t)n, now, NULL))
daemon->queries_forwarded++;
else
daemon->local_answer++;
}
/* sets new last_server */
void reply_query(int fd, int family, time_t now)
{
/* packet from peer server, extract data for cache, and send to
original requester */
HEADER *header;
union mysockaddr serveraddr;
struct frec *forward;
socklen_t addrlen = sizeof(serveraddr);
ssize_t n = recvfrom(fd, daemon->packet, daemon->edns_pktsz, 0, &serveraddr.sa, &addrlen);
size_t nn;
struct server *server;
/* packet buffer overwritten */
daemon->srv_save = NULL;
/* Determine the address of the server replying so that we can mark that as good */
serveraddr.sa.sa_family = family;
#ifdef HAVE_IPV6
if (serveraddr.sa.sa_family == AF_INET6)
serveraddr.in6.sin6_flowinfo = 0;
#endif
/* spoof check: answer must come from known server, */
for (server = daemon->servers; server; server = server->next)
if (!(server->flags & (SERV_LITERAL_ADDRESS | SERV_NO_ADDR)) &&
sockaddr_isequal(&server->addr, &serveraddr))
break;
header = (HEADER *)daemon->packet;
if (!server ||
n < (int)sizeof(HEADER) || !header->qr ||
!(forward = lookup_frec(ntohs(header->id), questions_crc(header, n, daemon->namebuff))))
return;
server = forward->sentto;
if ((header->rcode == SERVFAIL || header->rcode == REFUSED) &&
!(daemon->options & OPT_ORDER) &&
forward->forwardall == 0)
/* for broken servers, attempt to send to another one. */
{
unsigned char *pheader;
size_t plen;
int is_sign;
/* recreate query from reply */
pheader = find_pseudoheader(header, (size_t)n, &plen, NULL, &is_sign);
if (!is_sign)
{
header->ancount = htons(0);
header->nscount = htons(0);
header->arcount = htons(0);
if ((nn = resize_packet(header, (size_t)n, pheader, plen)))
{
header->qr = 0;
header->tc = 0;
forward_query(-1, NULL, NULL, 0, header, nn, now, forward);
return;
}
}
}
if ((forward->sentto->flags & SERV_TYPE) == 0)
{
if (header->rcode == SERVFAIL || header->rcode == REFUSED)
server = NULL;
else
{
struct server *last_server;
/* find good server by address if possible, otherwise assume the last one we sent to */
for (last_server = daemon->servers; last_server; last_server = last_server->next)
if (!(last_server->flags & (SERV_LITERAL_ADDRESS | SERV_HAS_DOMAIN | SERV_FOR_NODOTS | SERV_NO_ADDR)) &&
sockaddr_isequal(&last_server->addr, &serveraddr))
{
server = last_server;
break;
}
}
if (!(daemon->options & OPT_ALL_SERVERS))
daemon->last_server = server;
}
/* If the answer is an error, keep the forward record in place in case
we get a good reply from another server. Kill it when we've
had replies from all to avoid filling the forwarding table when
everything is broken */
if (forward->forwardall == 0 || --forward->forwardall == 1 ||
(header->rcode != REFUSED && header->rcode != SERVFAIL))
{
if ((nn = process_reply(header, now, server, (size_t)n)))
{
header->id = htons(forward->orig_id);
header->ra = 1; /* recursion if available */
send_from(forward->fd, daemon->options & OPT_NOWILD, daemon->packet, nn,
&forward->source, &forward->dest, forward->iface);
}
free_frec(forward); /* cancel */
}
}
void receive_query(struct listener *listen, time_t now)
{
struct dns_header *header = (struct dns_header *)daemon->packet;
union mysockaddr source_addr;
unsigned short type;
struct all_addr dst_addr;
struct in_addr netmask, dst_addr_4;
size_t m;
ssize_t n;
int if_index = 0;
struct iovec iov[1];
struct msghdr msg;
struct cmsghdr *cmptr;
union {
struct cmsghdr align; /* this ensures alignment */
#ifdef HAVE_IPV6
char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))];
#endif
#if defined(HAVE_LINUX_NETWORK)
char control[CMSG_SPACE(sizeof(struct in_pktinfo))];
#elif defined(IP_RECVDSTADDR) && defined(HAVE_SOLARIS_NETWORK)
char control[CMSG_SPACE(sizeof(struct in_addr)) +
CMSG_SPACE(sizeof(unsigned int))];
#elif defined(IP_RECVDSTADDR)
char control[CMSG_SPACE(sizeof(struct in_addr)) +
CMSG_SPACE(sizeof(struct sockaddr_dl))];
#endif
} control_u;
/* packet buffer overwritten */
daemon->srv_save = NULL;
if (listen->iface && listen->family == AF_INET && option_bool(OPT_NOWILD))
{
dst_addr_4 = listen->iface->addr.in.sin_addr;
netmask = listen->iface->netmask;
}
else
{
dst_addr_4.s_addr = 0;
netmask.s_addr = 0;
}
iov[0].iov_base = daemon->packet;
iov[0].iov_len = daemon->edns_pktsz;
msg.msg_control = control_u.control;
msg.msg_controllen = sizeof(control_u);
msg.msg_flags = 0;
msg.msg_name = &source_addr;
msg.msg_namelen = sizeof(source_addr);
msg.msg_iov = iov;
msg.msg_iovlen = 1;
if ((n = recvmsg(listen->fd, &msg, 0)) == -1)
return;
if (n < (int)sizeof(struct dns_header) ||
(msg.msg_flags & MSG_TRUNC) ||
(header->hb3 & HB3_QR))
return;
source_addr.sa.sa_family = listen->family;
#ifdef HAVE_IPV6
if (listen->family == AF_INET6)
source_addr.in6.sin6_flowinfo = 0;
#endif
if (!option_bool(OPT_NOWILD))
{
struct ifreq ifr;
if (msg.msg_controllen < sizeof(struct cmsghdr))
return;
#if defined(HAVE_LINUX_NETWORK)
if (listen->family == AF_INET)
for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_PKTINFO)
{
union {
unsigned char *c;
struct in_pktinfo *p;
} p;
p.c = CMSG_DATA(cmptr);
dst_addr_4 = dst_addr.addr.addr4 = p.p->ipi_spec_dst;
if_index = p.p->ipi_ifindex;
}
#elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF)
if (listen->family == AF_INET)
{
for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
{
union {
unsigned char *c;
unsigned int *i;
struct in_addr *a;
#ifndef HAVE_SOLARIS_NETWORK
struct sockaddr_dl *s;
#endif
} p;
p.c = CMSG_DATA(cmptr);
if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVDSTADDR)
dst_addr_4 = dst_addr.addr.addr4 = *(p.a);
else if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF)
#ifdef HAVE_SOLARIS_NETWORK
if_index = *(p.i);
#else
if_index = p.s->sdl_index;
#endif
}
}
#endif
#ifdef HAVE_IPV6
if (listen->family == AF_INET6)
{
for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
if (cmptr->cmsg_level == IPPROTO_IPV6 && cmptr->cmsg_type == daemon->v6pktinfo)
{
union {
unsigned char *c;
struct in6_pktinfo *p;
} p;
p.c = CMSG_DATA(cmptr);
dst_addr.addr.addr6 = p.p->ipi6_addr;
if_index = p.p->ipi6_ifindex;
}
}
#endif
/* enforce available interface configuration */
if (!indextoname(listen->fd, if_index, ifr.ifr_name) ||
!iface_check(listen->family, &dst_addr, ifr.ifr_name))
return;
if (listen->family == AF_INET && option_bool(OPT_LOCALISE))
{
struct irec *iface;
/* get the netmask of the interface whch has the address we were sent to.
This is no neccessarily the interface we arrived on. */
for (iface = daemon->interfaces; iface; iface = iface->next)
if (iface->addr.sa.sa_family == AF_INET &&
iface->addr.in.sin_addr.s_addr == dst_addr_4.s_addr)
break;
/* interface may be new */
if (!iface)
enumerate_interfaces();
for (iface = daemon->interfaces; iface; iface = iface->next)
if (iface->addr.sa.sa_family == AF_INET &&
iface->addr.in.sin_addr.s_addr == dst_addr_4.s_addr)
break;
/* If we failed, abandon localisation */
if (iface)
netmask = iface->netmask;
else
dst_addr_4.s_addr = 0;
}
}
if (extract_request(header, (size_t)n, daemon->namebuff, &type))
{
char types[20];
querystr(types, type);
if (listen->family == AF_INET)
log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff,
(struct all_addr *)&source_addr.in.sin_addr, types);
#ifdef HAVE_IPV6
else
log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff,
(struct all_addr *)&source_addr.in6.sin6_addr, types);
#endif
}
m = answer_request (header, ((char *) header) + PACKETSZ, (size_t)n,
dst_addr_4, netmask, now);
if (m >= 1)
{
send_from(listen->fd, option_bool(OPT_NOWILD), (char *)header,
m, &source_addr, &dst_addr, if_index);
daemon->local_answer++;
}
else if (forward_query(listen->fd, &source_addr, &dst_addr, if_index,
header, (size_t)n, now, NULL))
daemon->queries_forwarded++;
else
daemon->local_answer++;
}
int main (int argc, char **argv)
{
int i;
int cachesize = CACHESIZ;
int port = NAMESERVER_PORT;
unsigned int options;
int first_loop = 1;
#ifdef HAVE_FILE_SYSTEM
int logged_resolv = 0, logged_lease = 0;
char *resolv = RESOLVFILE;
char *runfile = RUNFILE;
time_t resolv_changed = 0;
char *lease_file = NULL;
off_t lease_file_size = (off_t)0;
ino_t lease_file_inode = (ino_t)0;
#endif
struct irec *iface;
int peerfd, peerfd6;
struct irec *interfaces = NULL;
char *mxname = NULL;
char *mxtarget = NULL;
char *domain_suffix = NULL;
char *username = CHUSER;
struct iname *if_names = NULL;
struct iname *if_addrs = NULL;
struct server *serv_addrs = NULL;
char *dnamebuff, *packet;
struct server *servers, *last_server;
sighup = 1; /* init cache the first time through */
sigusr1 = 0; /* but don't dump */
signal(SIGUSR1, sig_handler);
signal(SIGHUP, sig_handler);
/* These get allocated here to avoid overflowing the small stack
on embedded systems. dnamebuff is big enough to hold one
maximal sixed domain name and gets passed into all the processing
code. We manage to get away with one buffer. */
dnamebuff = safe_malloc(MAXDNAME);
/* Size: we check after adding each record, so there must be
memory for the largest packet, and the largest record */
packet = safe_malloc(PACKETSZ+MAXDNAME+RRFIXEDSZ);
#ifdef HAVE_FILE_SYSTEM
options = read_opts(argc, argv, dnamebuff, &resolv, &mxname, &mxtarget, &lease_file,
&username, &domain_suffix, &runfile, &if_names, &if_addrs,
&serv_addrs, &cachesize, &port) ;
#else
options = read_opts(argc, argv, dnamebuff, NULL, &mxname, &mxtarget, NULL,
&username, &domain_suffix, NULL, &if_names, &if_addrs,
&serv_addrs, &cachesize, &port) ;
#endif
/* peerfd is not bound to a low port
so that we can send queries out on it without them getting
blocked at firewalls */
if ((peerfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1 &&
errno != EAFNOSUPPORT &&
errno != EINVAL)
die("dnsmasq: cannot create socket: %s", NULL);
#ifdef HAVE_IPV6
if ((peerfd6 = socket(AF_INET6, SOCK_DGRAM, 0)) == -1 &&
errno != EAFNOSUPPORT &&
errno != EINVAL)
die("dnsmasq: cannot create IPv6 socket: %s", NULL);
#else
peerfd6 = -1;
#endif
if (peerfd == -1 && peerfd6 == -1)
die("dnsmasq: no kernel support for IPv4 _or_ IPv6.", NULL);
interfaces = find_all_interfaces(if_names, if_addrs, port);
/* open a socket bound to NS port on each local interface.
this is necessary to ensure that our replies originate from
the address they were sent to. See Stevens page 531 */
for (iface = interfaces; iface; iface = iface->next)
{
if ((iface->fd = socket(iface->addr.sa.sa_family, SOCK_DGRAM, 0)) == -1)
die("cannot create socket: %s", NULL);
if (bind(iface->fd, &iface->addr.sa, sa_len(&iface->addr)))
die("bind failed: %s", NULL);
}
forward_init(1);
cache_init(cachesize, options & OPT_LOG);
setbuf(stdout, NULL);
#ifdef HAVE_FILE_SYSTEM
if (!(options & OPT_DEBUG))
{
FILE *pidfile;
struct passwd *ent_pw;
/* The following code "daemonizes" the process.
See Stevens section 12.4 */
#ifdef HAVE_FORK
if (fork() != 0 )
exit(0);
setsid();
if (fork() != 0)
exit(0);
#endif
chdir("/");
umask(022); /* make pidfile 0644 */
/* write pidfile _after_ forking ! */
if (runfile && (pidfile = fopen(runfile, "w")))
{
fprintf(pidfile, "%d\n", (int) getpid());
fclose(pidfile);
}
umask(0);
for (i=0; i<64; i++)
{
if (i == peerfd || i == peerfd6)
continue;
for (iface = interfaces; iface; iface = iface->next)
if (iface->fd == i)
break;
if (!iface)
close(i);
}
/* Change uid and gid for security */
if (username && (ent_pw = getpwnam(username)))
{
gid_t dummy;
struct group *gp;
/* remove all supplimentary groups */
setgroups(0, &dummy);
/* change group to "dip" if it exists, for /etc/ppp/resolv.conf
otherwise get the group for "nobody" */
if ((gp = getgrnam("dip")) || (gp = getgrgid(ent_pw->pw_gid)))
setgid(gp->gr_gid);
/* finally drop root */
setuid(ent_pw->pw_uid);
}
}
#else
#endif
/* In debug mode, log to stderr too and cut the prefix crap. */
openlog("dnsmasq", options & OPT_DEBUG ? LOG_PERROR : LOG_PID, LOG_DAEMON);
if (cachesize)
syslog(LOG_INFO, "started, version %s cachesize %d", VERSION, cachesize);
else
syslog(LOG_INFO, "started, version %s cache disabled", VERSION);
if (mxname)
syslog(LOG_INFO, "serving MX record for mailhost %s target %s",
mxname, mxtarget);
if (getuid() == 0 || geteuid() == 0)
syslog(LOG_WARNING, "failed to drop root privs");
serv_addrs = servers = last_server = check_servers(serv_addrs, interfaces, peerfd, peerfd6);
while (1)
{
int ready, maxfd = peerfd > peerfd6 ? peerfd : peerfd6;
fd_set rset;
HEADER *header;
#ifdef HAVE_FILE_SYSTEM
struct stat statbuf;
#endif
if (first_loop)
/* do init stuff only first time round. */
{
first_loop = 0;
ready = 0;
}
else
{
FD_ZERO(&rset);
if (peerfd != -1)
FD_SET(peerfd, &rset);
if (peerfd6 != -1)
FD_SET(peerfd6, &rset);
for (iface = interfaces; iface; iface = iface->next)
{
FD_SET(iface->fd, &rset);
if (iface->fd > maxfd)
maxfd = iface->fd;
}
ready = select(maxfd+1, &rset, NULL, NULL, NULL);
if (ready == -1)
{
if (errno == EINTR)
ready = 0; /* do signal handlers */
else
continue;
}
}
#ifdef HAVE_FILE_SYSTEM
if (sighup)
{
signal(SIGHUP, SIG_IGN);
cache_reload(options & OPT_NO_HOSTS, dnamebuff);
if (resolv && (options & OPT_NO_POLL))
servers = last_server =
check_servers(reload_servers(resolv, dnamebuff, servers),
interfaces, peerfd, peerfd6);
sighup = 0;
signal(SIGHUP, sig_handler);
}
if (sigusr1)
{
signal(SIGUSR1, SIG_IGN);
dump_cache(options & (OPT_DEBUG | OPT_LOG), cachesize);
sigusr1 = 0;
signal(SIGUSR1, sig_handler);
}
if (resolv && !(options & OPT_NO_POLL))
{
if (stat(resolv, &statbuf) == -1)
{
if (!logged_resolv)
syslog(LOG_WARNING, "failed to access %s: %m", resolv);
logged_resolv = 1;
}
else
{
logged_resolv = 0;
if ((statbuf.st_mtime > resolv_changed) &&
(statbuf.st_mtime < time(NULL) || resolv_changed == 0))
{
resolv_changed = statbuf.st_mtime;
servers = last_server =
check_servers(reload_servers(resolv, dnamebuff, servers),
interfaces, peerfd, peerfd6);
}
}
}
#else
#endif
#ifdef HAVE_FILE_SYSTEM
if (lease_file)
{
if (stat(lease_file, &statbuf) == -1)
{
if (!logged_lease)
syslog(LOG_WARNING, "failed to access %s: %m", lease_file);
logged_lease = 1;
}
else
{
logged_lease = 0;
if ((lease_file_size == (off_t)0) ||
(statbuf.st_size > lease_file_size) ||
(statbuf.st_ino != lease_file_inode))
{
lease_file_size = statbuf.st_size;
lease_file_inode = statbuf.st_ino;
load_dhcp(lease_file, domain_suffix, time(NULL), dnamebuff);
}
}
}
#else
#endif
if (ready == 0)
continue; /* no sockets ready */
if (peerfd != -1 && FD_ISSET(peerfd, &rset))
last_server = reply_query(peerfd, packet, dnamebuff, last_server);
if (peerfd6 != -1 && FD_ISSET(peerfd6, &rset))
last_server = reply_query(peerfd6, packet, dnamebuff, last_server);
for (iface = interfaces; iface; iface = iface->next)
{
if (FD_ISSET(iface->fd, &rset))
{
/* request packet, deal with query */
union mysockaddr udpaddr;
socklen_t udplen = sizeof(udpaddr);
int m, n = recvfrom(iface->fd, packet, PACKETSZ, 0, &udpaddr.sa, &udplen);
udpaddr.sa.sa_family = iface->addr.sa.sa_family;
#ifdef HAVE_IPV6
if (udpaddr.sa.sa_family == AF_INET6)
udpaddr.in6.sin6_flowinfo = htonl(0);
#endif
header = (HEADER *)packet;
if (n >= (int)sizeof(HEADER) && !header->qr)
{
m = answer_request (header, ((char *) header) + PACKETSZ, (unsigned int)n,
mxname, mxtarget, options, dnamebuff);
if (m >= 1)
{
/* answered from cache, send reply */
sendto(iface->fd, (char *)header, m, 0,
&udpaddr.sa, sa_len(&udpaddr));
}
else
{
/* cannot answer from cache, send on to real nameserver */
last_server = forward_query(iface->fd, peerfd, peerfd6, &udpaddr, header, n,
options && OPT_ORDER, dnamebuff,
servers, last_server);
}
}
}
}
}
return 0;
}
