#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
static char rcsid[] = "$Id: res_send.c,v 1.6 2003/02/18 17:29:25 majka Exp $";
#endif
#define CHECK_SRVR_ADDR 1
#include <sys/param.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <ifaddrs.h>
#include <net/if.h>
#include <stdio.h>
#include <netdb.h>
#include <errno.h>
#include "nameser8_compat.h"
#include "resolv8_compat.h"
#if defined(BSD) && (BSD >= 199306)
# include <stdlib.h>
# include <string.h>
# include <unistd.h>
#else
# include "portability.h"
#endif
#if defined(USE_OPTIONS_H)
# include "options.h"
#endif
void _res_close __P((void));
static int s = -1;
static int connected = 0;
static int vc = 0;
#ifndef FD_SET
#define NFDBITS 32
#define FD_SETSIZE 32
#define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
#define FD_CLR(n, p) ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
#define FD_ISSET(n, p) ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
#define FD_ZERO(p) bzero((char *)(p), sizeof(*(p)))
#endif
#if (defined(BSD) && (BSD >= 199103)) || defined(linux)
# define CAN_RECONNECT 1
#else
# define CAN_RECONNECT 0
#endif
#ifndef DEBUG
# define Dprint(cond, args)
# define DprintQ(cond, args, query, size)
# define Aerror(file, string, error, address)
# define Perror(file, string, error)
#else
# define Dprint(cond, args) if (cond) {fprintf args;} else {}
# define DprintQ(cond, args, query, size) if (cond) {\
fprintf args;\
__fp_nquery(query, size, stdout);\
} else {}
static void
Aerror(file, string, error, address)
FILE *file;
char *string;
int error;
struct sockaddr_in address;
{
int save = errno;
if (_res.options & RES_DEBUG) {
fprintf(file, "res_send: %s ([%s].%u): %s\n",
string,
inet_ntoa(address.sin_addr),
ntohs(address.sin_port),
strerror(error));
}
errno = save;
}
static void
Perror(file, string, error)
FILE *file;
char *string;
int error;
{
int save = errno;
if (_res.options & RES_DEBUG) {
fprintf(file, "res_send: %s: %s\n",
string, strerror(error));
}
errno = save;
}
#endif
static res_send_qhook Qhook = NULL;
static res_send_rhook Rhook = NULL;
void
res_send_setqhook(hook)
res_send_qhook hook;
{
Qhook = hook;
}
void
res_send_setrhook(hook)
res_send_rhook hook;
{
Rhook = hook;
}
int
res_isourserver(inp)
const struct sockaddr_in *inp;
{
struct sockaddr_in ina;
register int ns, ret;
ina = *inp;
ret = 0;
for (ns = 0; ns < _res.nscount; ns++) {
register const struct sockaddr_in *srv = &_res.nsaddr_list[ns];
if (srv->sin_family == ina.sin_family &&
srv->sin_port == ina.sin_port &&
(srv->sin_addr.s_addr == INADDR_ANY ||
srv->sin_addr.s_addr == ina.sin_addr.s_addr)) {
ret++;
break;
}
}
return (ret);
}
int
res_nameinquery(name, type, class, buf, eom)
const char *name;
register int type, class;
const u_char *buf, *eom;
{
register const u_char *cp = buf + HFIXEDSZ;
int qdcount = ntohs(((HEADER*)buf)->qdcount);
while (qdcount-- > 0) {
char tname[MAXDNAME+1];
register int n, ttype, tclass;
n = dn_expand(buf, eom, cp, tname, sizeof tname);
if (n < 0)
return (-1);
cp += n;
ttype = _getshort(cp); cp += INT16SZ;
tclass = _getshort(cp); cp += INT16SZ;
if (ttype == type &&
tclass == class &&
strcasecmp(tname, name) == 0)
return (1);
}
return (0);
}
int
res_queriesmatch(buf1, eom1, buf2, eom2)
const u_char *buf1, *eom1;
const u_char *buf2, *eom2;
{
register const u_char *cp = buf1 + HFIXEDSZ;
int qdcount = ntohs(((HEADER*)buf1)->qdcount);
if (qdcount != ntohs(((HEADER*)buf2)->qdcount))
return (0);
while (qdcount-- > 0) {
char tname[MAXDNAME+1];
register int n, ttype, tclass;
n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
if (n < 0)
return (-1);
cp += n;
ttype = _getshort(cp); cp += INT16SZ;
tclass = _getshort(cp); cp += INT16SZ;
if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
return (0);
}
return (1);
}
static int dns_is_local_name(const u_int8_t *name)
{
const u_int8_t *d0 = NULL; const u_int8_t *d1 = NULL; const u_int8_t *d2 = NULL; const u_int8_t *d3 = NULL;
if (name == NULL || *name == 0) return 0;
while (*name)
{
d3 = d2;
d2 = d1;
d1 = d0;
d0 = name;
name += 1 + *name;
}
if (d0[0] == 5 && strncasecmp((char *)d0+1, "local", 5) == 0) return 1;
if (d1 && d1[0] == 5 && strncasecmp((char *)d1+1, "local", 5) == 0 &&
d0[0] == 4 && strncasecmp((char *)d0+1, "arpa", 4) == 0) return 1;
if (d1 && d1[0] == 5 && strncasecmp((char *)d1+1, "local", 5) == 0 &&
d0[0] == 3 && strncasecmp((char *)d0+1, "int", 3) == 0) return 1;
if (d3 && d3[0] == 3 && strncasecmp((char *)d3+1, "254", 3) == 0 &&
d2 && d2[0] == 3 && strncasecmp((char *)d2+1, "169", 3) == 0 &&
d1 && d1[0] == 7 && strncasecmp((char *)d1+1, "in-addr", 7) == 0 &&
d0[0] == 4 && strncasecmp((char *)d0+1, "arpa", 4) == 0) return 1;
return 0;
}
#define DNS_LOCAL_DOMAIN_SERVICE_PORT 5353
#define DNS_HEADER_SIZE 12
static const struct sockaddr_in mDNS_addr =
{
sizeof(mDNS_addr),
AF_INET,
htons(DNS_LOCAL_DOMAIN_SERVICE_PORT),
{htonl(0xE00000FB)}
};
int
res_send(buf, buflen, ans, anssiz)
const u_char *buf;
int buflen;
u_char *ans;
int anssiz;
{
HEADER *hp = (HEADER *) buf;
HEADER *anhp = (HEADER *) ans;
int gotsomewhere, connreset, terrno, try, v_circuit, resplen, ns;
register int n;
u_int badns;
int multicast;
if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
return (-1);
}
DprintQ((_res.options & RES_DEBUG) || (_res.pfcode & RES_PRF_QUERY),
(stdout, ";; res_send()\n"), buf, buflen);
v_circuit = (_res.options & RES_USEVC) || buflen > PACKETSZ;
gotsomewhere = 0;
connreset = 0;
terrno = ETIMEDOUT;
badns = 0;
if (dns_is_local_name((u_int8_t*)(buf + DNS_HEADER_SIZE))) {
multicast = 1;
v_circuit = 0;
} else {
multicast = 0;
}
for (try = 0; try < _res.retry; try++) {
for (ns = 0; (multicast == 0 && ns < _res.nscount) ||
(multicast == 1 && ns < 1) ; ns++) {
struct sockaddr_in *nsap;
if (multicast == 0)
nsap = &_res.nsaddr_list[ns];
else
nsap = (struct sockaddr_in*)&mDNS_addr;
same_ns:
if (badns & (1 << ns)) {
_res_close();
goto next_ns;
}
if (Qhook) {
int done = 0, loops = 0;
do {
res_sendhookact act;
act = (*Qhook)(&nsap, &buf, &buflen,
ans, anssiz, &resplen);
switch (act) {
case res_goahead:
done = 1;
break;
case res_nextns:
_res_close();
goto next_ns;
case res_done:
return (resplen);
case res_modified:
if (++loops < 42)
break;
case res_error:
default:
return (-1);
}
} while (!done);
}
Dprint(_res.options & RES_DEBUG,
(stdout, ";; Querying server (# %d) address = %s\n",
ns + 1, inet_ntoa(nsap->sin_addr)));
if (v_circuit) {
int truncated;
struct iovec iov[2];
u_short len;
u_char *cp;
try = _res.retry;
truncated = 0;
if ((s < 0) || (!vc)) {
if (s >= 0)
_res_close();
s = socket(PF_INET, SOCK_STREAM, 0);
if (s < 0) {
terrno = errno;
Perror(stderr, "socket(vc)", errno);
return (-1);
}
errno = 0;
if (connect(s, (struct sockaddr *)nsap,
sizeof(struct sockaddr)) < 0) {
terrno = errno;
Aerror(stderr, "connect/vc",
errno, *nsap);
badns |= (1 << ns);
_res_close();
goto next_ns;
}
vc = 1;
}
putshort((u_short)buflen, (u_char*)&len);
iov[0].iov_base = (caddr_t)&len;
iov[0].iov_len = INT16SZ;
iov[1].iov_base = (caddr_t)buf;
iov[1].iov_len = buflen;
if (writev(s, iov, 2) != (INT16SZ + buflen)) {
terrno = errno;
Perror(stderr, "write failed", errno);
badns |= (1 << ns);
_res_close();
goto next_ns;
}
cp = ans;
len = INT16SZ;
while ((n = read(s, (char *)cp, (int)len)) > 0) {
cp += n;
if ((len -= n) <= 0)
break;
}
if (n <= 0) {
terrno = errno;
Perror(stderr, "read failed", errno);
_res_close();
if (terrno == ECONNRESET && !connreset) {
connreset = 1;
_res_close();
goto same_ns;
}
_res_close();
goto next_ns;
}
resplen = _getshort(ans);
if (resplen > anssiz) {
Dprint(_res.options & RES_DEBUG,
(stdout, ";; response truncated\n")
);
truncated = 1;
len = anssiz;
} else
len = resplen;
cp = ans;
while (len != 0 &&
(n = read(s, (char *)cp, (int)len)) > 0) {
cp += n;
len -= n;
}
if (n <= 0) {
terrno = errno;
Perror(stderr, "read(vc)", errno);
_res_close();
goto next_ns;
}
if (truncated) {
anhp->tc = 1;
len = resplen - anssiz;
while (len != 0) {
char junk[PACKETSZ];
n = (len > sizeof(junk)
? sizeof(junk)
: len);
if ((n = read(s, junk, n)) > 0)
len -= n;
else
break;
}
}
} else {
struct timeval timeout;
fd_set dsmask;
struct sockaddr_in from;
unsigned int fromlen;
if ((s < 0) || vc) {
if (vc)
_res_close();
s = socket(PF_INET, SOCK_DGRAM, 0);
if (s < 0) {
#if !CAN_RECONNECT
bad_dg_sock:
#endif
terrno = errno;
Perror(stderr, "socket(dg)", errno);
return (-1);
}
connected = 0;
}
if ((_res.nscount == 1 || (try == 0 && ns == 0)) && multicast == 0) {
if (!connected) {
if (connect(s, (struct sockaddr *)nsap,
sizeof(struct sockaddr)
) < 0) {
Aerror(stderr,
"connect(dg)",
errno, *nsap);
badns |= (1 << ns);
_res_close();
goto next_ns;
}
connected = 1;
}
if (send(s, (char*)buf, buflen, 0) != buflen) {
Perror(stderr, "send", errno);
badns |= (1 << ns);
_res_close();
goto next_ns;
}
} else {
if (connected) {
#if CAN_RECONNECT
struct sockaddr_in no_addr;
no_addr.sin_family = AF_INET;
no_addr.sin_addr.s_addr = INADDR_ANY;
no_addr.sin_port = 0;
(void) connect(s,
(struct sockaddr *)
&no_addr,
sizeof(no_addr));
#else
int s1 = socket(PF_INET, SOCK_DGRAM,0);
if (s1 < 0)
goto bad_dg_sock;
(void) dup2(s1, s);
(void) close(s1);
Dprint(_res.options & RES_DEBUG,
(stdout, ";; new DG socket\n"))
#endif
connected = 0;
errno = 0;
}
if (multicast) {
struct ifaddrs* addrs;
struct ifaddrs* curAddr;
const int twofivefive = 255;
if(setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL, &twofivefive, sizeof(twofivefive))) {
Perror(stderr, "setsocketopt - IP_MULTICAST_TTL", errno);
_res_close();
return (0);
}
if (getifaddrs(&addrs) != 0)
{
Perror(stderr, "getifaddrs", errno);
_res_close();
return (0);
}
for (curAddr = addrs; curAddr != NULL; curAddr = curAddr->ifa_next) {
if ((curAddr->ifa_addr->sa_family) == AF_INET &&
(curAddr->ifa_flags & IFF_MULTICAST) != 0 &&
(curAddr->ifa_flags & IFF_POINTOPOINT) == 0) {
struct in_addr* if_ip_addr = &((struct sockaddr_in*)curAddr->ifa_addr)->sin_addr;
if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF,
if_ip_addr, sizeof(*if_ip_addr)) != 0) {
freeifaddrs(addrs);
Perror(stderr, "setsocketopt - IP_MULTICAST_IF", errno);
_res_close();
return (0);
}
if (sendto(s, (char*)buf, buflen, 0,
(struct sockaddr *)nsap, sizeof *nsap) != buflen)
{
freeifaddrs(addrs);
Aerror(stderr, "sendto", errno, *nsap);
_res_close();
return (0);
}
}
}
freeifaddrs(addrs);
} else {
if (sendto(s, (char*)buf, buflen, 0,
(struct sockaddr *)nsap,
sizeof(struct sockaddr))
!= buflen) {
Aerror(stderr, "sendto", errno, *nsap);
badns |= (1 << ns);
_res_close();
goto next_ns;
}
}
}
timeout.tv_sec = (_res.retrans << try);
if (try > 0)
timeout.tv_sec /= _res.nscount;
if ((long) timeout.tv_sec <= 0 || multicast)
timeout.tv_sec = 1;
timeout.tv_usec = 0;
wait:
FD_ZERO(&dsmask);
FD_SET(s, &dsmask);
n = select(s+1, &dsmask, (fd_set *)NULL,
(fd_set *)NULL, &timeout);
if (n < 0) {
Perror(stderr, "select", errno);
_res_close();
goto next_ns;
}
if (n == 0) {
Dprint(_res.options & RES_DEBUG,
(stdout, ";; timeout\n"));
gotsomewhere = 1;
_res_close();
goto next_ns;
}
errno = 0;
fromlen = sizeof(struct sockaddr_in);
resplen = recvfrom(s, (char*)ans, anssiz, 0,
(struct sockaddr *)&from, &fromlen);
if (resplen <= 0) {
Perror(stderr, "recvfrom", errno);
_res_close();
goto next_ns;
}
gotsomewhere = 1;
if (hp->id != anhp->id) {
DprintQ((_res.options & RES_DEBUG) ||
(_res.pfcode & RES_PRF_REPLY),
(stdout, ";; old answer:\n"),
ans, resplen);
goto wait;
}
#if CHECK_SRVR_ADDR
if (!(_res.options & RES_INSECURE1) &&
multicast == 0 && !res_isourserver(&from)) {
DprintQ((_res.options & RES_DEBUG) ||
(_res.pfcode & RES_PRF_REPLY),
(stdout, ";; not our server:\n"),
ans, resplen);
goto wait;
}
#endif
if (!(_res.options & RES_INSECURE2) &&
!res_queriesmatch(buf, buf + buflen,
ans, ans + anssiz)) {
DprintQ((_res.options & RES_DEBUG) ||
(_res.pfcode & RES_PRF_REPLY),
(stdout, ";; wrong query name:\n"),
ans, resplen);
goto wait;
}
if (anhp->rcode == SERVFAIL ||
anhp->rcode == NOTIMP ||
anhp->rcode == REFUSED) {
DprintQ(_res.options & RES_DEBUG,
(stdout, "server rejected query:\n"),
ans, resplen);
badns |= (1 << ns);
_res_close();
if (!_res.pfcode)
goto next_ns;
}
if (!(_res.options & RES_IGNTC) && anhp->tc) {
Dprint(_res.options & RES_DEBUG,
(stdout, ";; truncated answer\n"));
v_circuit = 1;
_res_close();
goto same_ns;
}
}
DprintQ((_res.options & RES_DEBUG) ||
(_res.pfcode & RES_PRF_REPLY),
(stdout, ";; got answer:\n"),
ans, resplen);
if ((v_circuit && (!(_res.options & RES_USEVC) || ns != 0)) ||
!(_res.options & RES_STAYOPEN)) {
_res_close();
}
if (Rhook) {
int done = 0, loops = 0;
do {
res_sendhookact act;
act = (*Rhook)(nsap, buf, buflen,
ans, anssiz, &resplen);
switch (act) {
case res_goahead:
case res_done:
done = 1;
break;
case res_nextns:
_res_close();
goto next_ns;
case res_modified:
if (++loops < 42)
break;
case res_error:
default:
return (-1);
}
} while (!done);
}
return (resplen);
next_ns: ;
}
}
_res_close();
if (!v_circuit)
if (!gotsomewhere)
errno = ECONNREFUSED;
else
errno = ETIMEDOUT;
else
errno = terrno;
return (-1);
}
void
_res_close()
{
if (s >= 0) {
(void) close(s);
s = -1;
connected = 0;
vc = 0;
}
}