this is the third phase of the "resolver overhaul" project.
this commit removes all of the old dns code, and switches the
__lookup_name backend (used by getaddrinfo, etc.) and the getnameinfo
function to use the newly implemented __res_mkquery and __res_msend
interfaces. for parsing the results, a new callback-based __dns_parse
function, based on __dns_get_rr from the old dns code, is used.
+++ /dev/null
-#include <stdint.h>
-#include <netdb.h>
-#include <stdio.h>
-#include <fcntl.h>
-#include <limits.h>
-#include <string.h>
-#include <sys/socket.h>
-#include <poll.h>
-#include <netinet/in.h>
-#include <time.h>
-#include <ctype.h>
-#include <unistd.h>
-#include <pthread.h>
-#include <errno.h>
-#include "__dns.h"
-#include "stdio_impl.h"
-
-#define TIMEOUT 5
-#define RETRY 1000
-#define PACKET_MAX 512
-#define PTR_MAX (64 + sizeof ".in-addr.arpa")
-
-static void cleanup(void *p)
-{
- close((intptr_t)p);
-}
-
-int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
-{
- time_t t0 = time(0);
- int fd;
- FILE *f, _f;
- unsigned char _buf[256];
- char line[64], *s, *z;
- union {
- struct sockaddr_in sin;
- struct sockaddr_in6 sin6;
- } sa = {0}, ns[3] = {{0}};
- socklen_t sl = sizeof sa.sin;
- int nns = 0;
- int family = AF_INET;
- unsigned char q[280] = "", *r = dest;
- int ql;
- int rlen;
- int got = 0, failed = 0;
- int errcode = EAI_AGAIN;
- int i, j;
- struct timespec ts;
- struct pollfd pfd;
- int id;
- int cs;
-
- pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
-
- /* Construct query template - RR and ID will be filled later */
- if (strlen(name)-1 >= 254U) return EAI_NONAME;
- q[2] = q[5] = 1;
- strcpy((char *)q+13, name);
- for (i=13; q[i]; i=j+1) {
- for (j=i; q[j] && q[j] != '.'; j++);
- if (j-i-1u > 62u) return EAI_NONAME;
- q[i-1] = j-i;
- }
- q[i+3] = 1;
- ql = i+4;
-
- /* Make a reasonably unpredictable id */
- clock_gettime(CLOCK_REALTIME, &ts);
- id = ts.tv_nsec + ts.tv_nsec/65536UL & 0xffff;
-
- /* 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, "nameserver", 10) || !isspace(line[10]))
- continue;
- for (s=line+11; isspace(*s); s++);
- for (z=s; *z && !isspace(*z); z++);
- *z=0;
- if (__ipparse(ns+nns, AF_UNSPEC, s) < 0) continue;
- ns[nns].sin.sin_port = htons(53);
- if (ns[nns++].sin.sin_family == AF_INET6) {
- family = AF_INET6;
- sl = sizeof sa.sin6;
- }
- }
- if (f) __fclose_ca(f);
- if (!nns) {
- ns[0].sin.sin_family = family = AF_INET;
- ns[0].sin.sin_port = htons(53);
- ns[0].sin.sin_addr.s_addr = htonl(0x7f000001);
- nns=1;
- sl = sizeof sa.sin;
- }
-
- /* 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 && errno == EAFNOSUPPORT) {
- if (family != AF_INET6) return EAI_SYSTEM;
- fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
- family = AF_INET;
- }
- if (fd < 0) return EAI_SYSTEM;
-
- /* Convert any IPv4 addresses in a mixed environment to v4-mapped */
- if (family == AF_INET6) {
- setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &(int){0}, sizeof 0);
- for (i=0; i<nns; i++) {
- if (ns[i].sin.sin_family != AF_INET) continue;
- memcpy(ns[i].sin6.sin6_addr.s6_addr+12,
- &ns[i].sin.sin_addr, 4);
- memcpy(ns[i].sin6.sin6_addr.s6_addr,
- "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
- ns[i].sin6.sin6_family = AF_INET6;
- ns[i].sin6.sin6_flowinfo = 0;
- ns[i].sin6.sin6_scope_id = 0;
- }
- }
-
- pthread_cleanup_push(cleanup, (void *)(intptr_t)fd);
- pthread_setcancelstate(cs, 0);
-
- if (bind(fd, (void *)&sa, sl) < 0) {
- errcode = EAI_SYSTEM;
- goto out;
- }
-
- pfd.fd = fd;
- pfd.events = POLLIN;
-
- /* Loop until we timeout; break early on success */
- for (; time(0)-t0 < TIMEOUT; ) {
-
- /* Query all configured namservers in parallel */
- for (i=0; i<rrcnt; i++) if (rr[i]) for (j=0; j<nns; j++) {
- q[0] = id+i >> 8;
- q[1] = id+i;
- q[ql-3] = rr[i];
- sendto(fd, q, ql, MSG_NOSIGNAL, (void *)&ns[j], sl);
- }
-
- /* Wait for a response, or until time to retry */
- if (poll(&pfd, 1, RETRY) <= 0) continue;
-
- /* Process any and all replies */
- while (got+failed < rrcnt && (rlen = recvfrom(fd, r, 512, 0,
- (void *)&sa, (socklen_t[1]){sl})) >= 2)
- {
- /* Ignore replies from addresses we didn't send to */
- for (i=0; i<nns; i++) if (!memcmp(ns+i, &sa, sl)) break;
- if (i==nns) continue;
-
- /* Compute index of the query from id */
- i = r[0]*256+r[1] - id & 0xffff;
- if ((unsigned)i >= rrcnt || !rr[i]) continue;
-
- /* Interpret the result code */
- switch (r[3] & 15) {
- case 0:
- got++;
- break;
- case 3:
- if (1) errcode = EAI_NONAME; else
- default:
- errcode = EAI_FAIL;
- failed++;
- }
-
- /* Mark this record as answered */
- rr[i] = 0;
- r += 512;
- }
-
- /* Check to see if we have answers to all queries */
- if (got+failed == rrcnt) break;
- }
-out:
- pthread_cleanup_pop(1);
-
- /* Return the number of results, or an error code if none */
- if (got) return got;
- return errcode;
-}
-
-static void mkptr4(char *s, const unsigned char *ip)
-{
- sprintf(s, "%d.%d.%d.%d.in-addr.arpa",
- ip[3], ip[2], ip[1], ip[0]);
-}
-
-static void mkptr6(char *s, const unsigned char *ip)
-{
- static const char xdigits[] = "0123456789abcdef";
- int i;
- for (i=15; i>=0; i--) {
- *s++ = xdigits[ip[i]&15]; *s++ = '.';
- *s++ = xdigits[ip[i]>>4]; *s++ = '.';
- }
- strcpy(s, "ip6.arpa");
-}
-
-int __dns_query(unsigned char *r, const void *a, int family, int ptr)
-{
- char buf[PTR_MAX];
- int rr[2], rrcnt = 1;
-
- if (ptr) {
- if (family == AF_INET6) mkptr6(buf, a);
- else mkptr4(buf, a);
- rr[0] = RR_PTR;
- a = buf;
- } else if (family == AF_INET6) {
- rr[0] = RR_AAAA;
- } else {
- rr[0] = RR_A;
- if (family != AF_INET) rr[rrcnt++] = RR_AAAA;
- }
-
- return __dns_doqueries(r, a, rr, rrcnt);
-}
-
-int __dn_expand(const unsigned char *, const unsigned char *, const unsigned char *, char *, int);
-
-int __dns_get_rr(void *dest, size_t stride, size_t maxlen, size_t limit, const unsigned char *r, int rr, int dec)
-{
- int qdcount, ancount;
- const unsigned char *p;
- char tmp[256];
- int found = 0;
- int len;
-
- if ((r[3]&15)) return 0;
- p = r+12;
- qdcount = r[4]*256 + r[5];
- ancount = r[6]*256 + r[7];
- if (qdcount+ancount > 64) return -1;
- while (qdcount--) {
- while (p-r < 512 && *p-1U < 127) p++;
- if (*p>193 || (*p==193 && p[1]>254) || p>r+506)
- return -1;
- p += 5 + !!*p;
- }
- while (ancount--) {
- while (p-r < 512 && *p-1U < 127) p++;
- if (*p>193 || (*p==193 && p[1]>254) || p>r+506)
- return -1;
- p += 1 + !!*p;
- len = p[8]*256 + p[9];
- if (p+len > r+512) return -1;
- if (p[1]==rr && len <= maxlen) {
- if (dec && __dn_expand(r, r+512, p+10, tmp, sizeof tmp)<0)
- return -1;
- if (dest && limit) {
- if (dec) strcpy(dest, tmp);
- else memcpy(dest, p+10, len);
- dest = (char *)dest + stride;
- limit--;
- }
- found++;
- }
- p += 10 + len;
- }
- return found;
-}
-
-int __dns_count_addrs(const unsigned char *r, int cnt)
-{
- int found=0, res, i;
- static const int p[2][2] = { { 4, RR_A }, { 16, RR_AAAA } };
-
- while (cnt--) {
- for (i=0; i<2; i++) {
- res = __dns_get_rr(0, 0, p[i][0], -1, r, p[i][1], 0);
- if (res < 0) return res;
- found += res;
- }
- r += 512;
- }
- return found;
-}
--- /dev/null
+#include <string.h>
+
+int __dns_parse(const unsigned char *r, int rlen, int (*callback)(void *, int, const void *, int, const void *), void *ctx)
+{
+ int qdcount, ancount;
+ const unsigned char *p;
+ int len;
+
+ if ((r[3]&15)) return 0;
+ p = r+12;
+ qdcount = r[4]*256 + r[5];
+ ancount = r[6]*256 + r[7];
+ if (qdcount+ancount > 64) return -1;
+ while (qdcount--) {
+ while (p-r < rlen && *p-1U < 127) p++;
+ if (*p>193 || (*p==193 && p[1]>254) || p>r+506)
+ return -1;
+ p += 5 + !!*p;
+ }
+ while (ancount--) {
+ while (p-r < rlen && *p-1U < 127) p++;
+ if (*p>193 || (*p==193 && p[1]>254) || p>r+506)
+ return -1;
+ p += 1 + !!*p;
+ len = p[8]*256 + p[9];
+ if (p+len > r+rlen) return -1;
+ if (callback(ctx, p[1], p+10, len, r) < 0) return -1;
+ p += 10 + len;
+ }
+ return 0;
+}
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
-#include "__dns.h"
+
+int __dns_parse(const unsigned char *, int, int (*)(void *, int, const void *, int, const void *), void *);
+int __dn_expand(const unsigned char *, const unsigned char *, const unsigned char *, char *, int);
+int __res_mkquery(int, const char *, int, int, const unsigned char *, int, const unsigned char*, unsigned char *, int);
+int __res_send(const unsigned char *, int, unsigned char *, int);
+
+#define PTR_MAX (64 + sizeof ".in-addr.arpa")
+#define RR_PTR 12
+
+static void mkptr4(char *s, const unsigned char *ip)
+{
+ sprintf(s, "%d.%d.%d.%d.in-addr.arpa",
+ ip[3], ip[2], ip[1], ip[0]);
+}
+
+static void mkptr6(char *s, const unsigned char *ip)
+{
+ static const char xdigits[] = "0123456789abcdef";
+ int i;
+ for (i=15; i>=0; i--) {
+ *s++ = xdigits[ip[i]&15]; *s++ = '.';
+ *s++ = xdigits[ip[i]>>4]; *s++ = '.';
+ }
+ strcpy(s, "ip6.arpa");
+}
+
+static int dns_parse_callback(void *c, int rr, const void *data, int len, const void *packet)
+{
+ char tmp[256];
+ if (rr != RR_PTR) return 0;
+ if (__dn_expand(packet, (const unsigned char *)packet + 512,
+ data, tmp, sizeof tmp) > 0)
+ strcpy(c, tmp);
+ return 0;
+
+}
int getnameinfo(const struct sockaddr *restrict sa, socklen_t sl,
char *restrict node, socklen_t nodelen,
char *restrict serv, socklen_t servlen,
int flags)
{
+ char ptr[PTR_MAX];
char buf[256];
- unsigned char reply[512];
int af = sa->sa_family;
unsigned char *a;
case AF_INET:
a = (void *)&((struct sockaddr_in *)sa)->sin_addr;
if (sl != sizeof(struct sockaddr_in)) return EAI_FAMILY;
+ mkptr4(ptr, a);
break;
case AF_INET6:
a = (void *)&((struct sockaddr_in6 *)sa)->sin6_addr;
if (sl != sizeof(struct sockaddr_in6)) return EAI_FAMILY;
+ if (memcmp(a, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12))
+ mkptr6(ptr, a);
+ else
+ mkptr4(ptr, a+12);
break;
default:
return EAI_FAMILY;
}
if (node && nodelen) {
- if ((flags & NI_NUMERICHOST)
- || __dns_query(reply, a, af, 1) <= 0
- || __dns_get_rr(buf, 0, 256, 1, reply, RR_PTR, 1) <= 0)
- {
+ buf[0] = 0;
+ if (!(flags & NI_NUMERICHOST)) {
+ unsigned char query[18+PTR_MAX], reply[512];
+ int qlen = __res_mkquery(0, ptr, 1, RR_PTR,
+ 0, 0, 0, query, sizeof query);
+ int rlen = __res_send(query, qlen, reply, sizeof reply);
+ buf[0] = 0;
+ if (rlen > 0)
+ __dns_parse(reply, rlen, dns_parse_callback, buf);
+ }
+ if (!*buf) {
if (flags & NI_NAMEREQD) return EAI_NONAME;
inet_ntop(af, a, buf, sizeof buf);
}
#include "lookup.h"
#include "stdio_impl.h"
#include "syscall.h"
-#include "__dns.h"
static int is_valid_hostname(const char *host)
{
return cnt;
}
-static int name_from_dns(struct address buf[static MAXADDRS], char canon[static 256], const char *name, int family)
+struct dpc_ctx {
+ struct address *addrs;
+ char *canon;
+ int cnt;
+};
+
+int __dns_parse(const unsigned char *, int, int (*)(void *, int, const void *, int, const void *), void *);
+int __dn_expand(const unsigned char *, const unsigned char *, const unsigned char *, char *, int);
+int __res_mkquery(int, const char *, int, int, const unsigned char *, int, const unsigned char*, unsigned char *, int);
+int __res_msend(int, const unsigned char *const *, const int *, unsigned char *const *, int *, int);
+
+#define RR_A 1
+#define RR_CNAME 5
+#define RR_AAAA 28
+
+static int dns_parse_callback(void *c, int rr, const void *data, int len, const void *packet)
{
- unsigned char reply[1024] = { 0 }, *p = reply;
char tmp[256];
- int i, cnt = 0;
-
- /* Perform one or more DNS queries for host */
- int result = __dns_query(reply, name, family, 0);
- if (result < 0) return result;
+ struct dpc_ctx *ctx = c;
+ switch (rr) {
+ case RR_A:
+ if (len != 4) return -1;
+ ctx->addrs[ctx->cnt].family = AF_INET;
+ memcpy(ctx->addrs[ctx->cnt++].addr, data, 4);
+ break;
+ case RR_AAAA:
+ if (len != 16) return -1;
+ ctx->addrs[ctx->cnt].family = AF_INET6;
+ memcpy(ctx->addrs[ctx->cnt++].addr, data, 16);
+ break;
+ case RR_CNAME:
+ if (__dn_expand(packet, (const unsigned char *)packet + 512,
+ data, tmp, sizeof tmp) > 0 && is_valid_hostname(tmp))
+ strcpy(ctx->canon, tmp);
+ break;
+ }
+ return 0;
+}
- for (i=0; i<result; i++) {
- if (family != AF_INET6) {
- int j = __dns_get_rr(&buf[cnt].addr, sizeof *buf, 4, MAXADDRS-cnt, p, RR_A, 0);
- while (j--) buf[cnt++].family = AF_INET;
- }
- if (family != AF_INET) {
- int j = __dns_get_rr(&buf[cnt].addr, sizeof *buf, 16, MAXADDRS-cnt, p, RR_AAAA, 0);
- while (j--) buf[cnt++].family = AF_INET6;
- }
- p += 512;
+static int name_from_dns(struct address buf[static MAXADDRS], char canon[static 256], const char *name, int family)
+{
+ unsigned char qbuf[2][280], abuf[2][512];
+ const unsigned char *qp[2] = { qbuf[0], qbuf[1] };
+ unsigned char *ap[2] = { abuf[0], abuf[1] };
+ int qlens[2], alens[2];
+ int i, nq = 0;
+ struct dpc_ctx ctx = { .addrs = buf, .canon = canon };
+
+ if (family != AF_INET6) {
+ qlens[nq] = __res_mkquery(0, name, 1, RR_A, 0, 0, 0,
+ qbuf[nq], sizeof *qbuf);
+ nq++;
}
- __dns_get_rr(tmp, 0, 256, 1, reply, RR_CNAME, 1);
- if (is_valid_hostname(tmp)) strcpy(canon, tmp);
- return cnt;
+ if (family != AF_INET) {
+ qlens[nq] = __res_mkquery(0, name, 1, RR_AAAA, 0, 0, 0,
+ qbuf[nq], sizeof *qbuf);
+ nq++;
+ }
+
+ if (__res_msend(nq, qp, qlens, ap, alens, sizeof *abuf) < 0) return EAI_SYSTEM;
+
+ for (i=0; i<nq; i++)
+ __dns_parse(abuf[i], alens[i], dns_parse_callback, &ctx);
+
+ return ctx.cnt;
}
int __lookup_name(struct address buf[static MAXADDRS], char canon[static 256], const char *name, int family, int flags)
projects / musl / commitdiff