static void cleanup(void *p)
{
- __syscall(SYS_close, (intptr_t)p);
+ struct pollfd *pfd = p;
+ for (int i=0; pfd[i].fd >= -1; i++)
+ if (pfd[i].fd >= 0) __syscall(SYS_close, pfd[i].fd);
}
static unsigned long mtime()
+ ts.tv_nsec / 1000000;
}
-int __res_msend(int nqueries, const unsigned char *const *queries,
- const int *qlens, unsigned char *const *answers, int *alens, int asize)
+int __res_msend_rc(int nqueries, const unsigned char *const *queries,
+ const int *qlens, unsigned char *const *answers, int *alens, int asize,
+ const struct resolvconf *conf)
{
int fd;
- FILE *f, _f;
- unsigned char _buf[256];
- char line[64], *s, *z;
- int timeout = 5000, attempts = 2, retry_interval;
+ int timeout, attempts, retry_interval, servfail_retry;
union {
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
- } sa = {0}, ns[3] = {{0}};
+ } sa = {0}, ns[MAXNS] = {{0}};
socklen_t sl = sizeof sa.sin;
int nns = 0;
int family = AF_INET;
int next;
int i, j;
int cs;
- struct pollfd pfd;
+ struct pollfd pfd[nqueries+2];
unsigned long t0, t1, t2;
- struct address iplit;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
- /* Get nameservers from resolv.conf, fallback to localhost */
- f = __fopen_rb_ca("/etc/resolv.conf", &_f, _buf, sizeof _buf);
- if (f) for (nns=0; nns<3 && fgets(line, sizeof line, f); ) {
- if (!strncmp(line, "options", 7) && isspace(line[7])) {
- unsigned long x;
- char *p, *z;
- p = strstr(line, "timeout:");
- if (p && isdigit(p[8])) {
- p += 8;
- x = strtoul(p, &z, 10);
- if (z != p) timeout = x < 30 ? x*1000 : 30000;
- }
- p = strstr(line, "attempts:");
- if (p && isdigit(p[9])) {
- p += 9;
- x = strtoul(p, &z, 10);
- if (z != p) attempts = x < 10 ? x : 10;
- if (!attempts) attempts = 1;
- }
- }
- if (strncmp(line, "nameserver", 10) || !isspace(line[10]))
- continue;
- for (s=line+11; isspace(*s); s++);
- for (z=s; *z && !isspace(*z); z++);
- *z=0;
-
- if (__lookup_ipliteral(&iplit, s, AF_UNSPEC)>0) {
- if (iplit.family == AF_INET) {
- memcpy(&ns[nns].sin.sin_addr, iplit.addr, 4);
- ns[nns].sin.sin_port = htons(53);
- ns[nns++].sin.sin_family = AF_INET;
- } else {
- sl = sizeof sa.sin6;
- memcpy(&ns[nns].sin6.sin6_addr, iplit.addr, 16);
- ns[nns].sin6.sin6_port = htons(53);
- ns[nns].sin6.sin6_scope_id = iplit.scopeid;
- ns[nns++].sin6.sin6_family = family = AF_INET6;
- }
+ timeout = 1000*conf->timeout;
+ attempts = conf->attempts;
+
+ for (nns=0; nns<conf->nns; nns++) {
+ const struct address *iplit = &conf->ns[nns];
+ if (iplit->family == AF_INET) {
+ memcpy(&ns[nns].sin.sin_addr, iplit->addr, 4);
+ ns[nns].sin.sin_port = htons(53);
+ ns[nns].sin.sin_family = AF_INET;
+ } else {
+ sl = sizeof sa.sin6;
+ memcpy(&ns[nns].sin6.sin6_addr, iplit->addr, 16);
+ ns[nns].sin6.sin6_port = htons(53);
+ ns[nns].sin6.sin6_scope_id = iplit->scopeid;
+ ns[nns].sin6.sin6_family = family = AF_INET6;
}
}
- if (f) __fclose_ca(f);
- if (!nns) {
- ns[0].sin.sin_family = AF_INET;
- ns[0].sin.sin_port = htons(53);
- ns[0].sin.sin_addr.s_addr = htonl(0x7f000001);
- nns=1;
- }
/* Get local address and open/bind a socket */
- sa.sin.sin_family = family;
fd = socket(family, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
/* Handle case where system lacks IPv6 support */
if (fd < 0 && family == AF_INET6 && errno == EAFNOSUPPORT) {
+ for (i=0; i<nns && conf->ns[nns].family == AF_INET6; i++);
+ if (i==nns) {
+ pthread_setcancelstate(cs, 0);
+ return -1;
+ }
fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
family = AF_INET;
+ sl = sizeof sa.sin;
+ }
+ sa.sin.sin_family = family;
+ if (fd < 0 || bind(fd, (void *)&sa, sl) < 0) {
+ if (fd >= 0) close(fd);
+ pthread_setcancelstate(cs, 0);
+ return -1;
}
- if (fd < 0 || bind(fd, (void *)&sa, sl) < 0) return -1;
/* Past this point, there are no errors. Each individual query will
* yield either no reply (indicated by zero length) or an answer
* packet which is up to the caller to interpret. */
- pthread_cleanup_push(cleanup, (void *)(intptr_t)fd);
+ for (i=0; i<nqueries; i++) pfd[i].fd = -1;
+ pfd[nqueries].fd = fd;
+ pfd[nqueries].events = POLLIN;
+ pfd[nqueries+1].fd = -2;
+
+ pthread_cleanup_push(cleanup, pfd);
pthread_setcancelstate(cs, 0);
/* Convert any IPv4 addresses in a mixed environment to v4-mapped */
memset(alens, 0, sizeof *alens * nqueries);
- pfd.fd = fd;
- pfd.events = POLLIN;
retry_interval = timeout / attempts;
next = 0;
t0 = t2 = mtime();
qlens[i], MSG_NOSIGNAL,
(void *)&ns[j], sl);
t1 = t2;
+ servfail_retry = 2 * nqueries;
}
/* Wait for a response, or until time to retry */
- if (poll(&pfd, 1, t1+retry_interval-t2) <= 0) continue;
+ if (poll(pfd, nqueries+1, t1+retry_interval-t2) <= 0) continue;
while ((rlen = recvfrom(fd, answers[next], asize, 0,
(void *)&sa, (socklen_t[1]){sl})) >= 0) {
- /* Ignore non-identifiable packets (no query id) */
- if (rlen < 2) continue;
+ /* Ignore non-identifiable packets */
+ if (rlen < 4) continue;
/* Ignore replies from addresses we didn't send to */
- for (i=0; i<nns && memcmp(ns+i, &sa, sl); i++);
- if (i==nns) continue;
+ for (j=0; j<nns && memcmp(ns+j, &sa, sl); j++);
+ if (j==nns) continue;
/* Find which query this answer goes with, if any */
for (i=next; i<nqueries && (
if (i==nqueries) continue;
if (alens[i]) continue;
+ /* Only accept positive or negative responses;
+ * retry immediately on server failure, and ignore
+ * all other codes such as refusal. */
+ switch (answers[next][3] & 15) {
+ case 0:
+ case 3:
+ break;
+ case 2:
+ if (servfail_retry && servfail_retry--)
+ sendto(fd, queries[i],
+ qlens[i], MSG_NOSIGNAL,
+ (void *)&ns[j], sl);
+ default:
+ continue;
+ }
+
/* Store answer in the right slot, or update next
* available temp slot if it's already in place. */
alens[i] = rlen;
return 0;
}
+
+int __res_msend(int nqueries, const unsigned char *const *queries,
+ const int *qlens, unsigned char *const *answers, int *alens, int asize)
+{
+ struct resolvconf conf;
+ if (__get_resolv_conf(&conf, 0, 0) < 0) return -1;
+ return __res_msend_rc(nqueries, queries, qlens, answers, alens, asize, &conf);
+}
projects / musl / blobdiff