Module Name: src
Committed By: christos
Date: Fri May 3 19:31:13 UTC 2013
Modified Files:
src/lib/libc/net: getaddrinfo.c
Log Message:
PR/32373, PR/25827: Add SRV lookup in getaddrinfo(3)
Per DNS-SD (RFC 2782), but only enabled if AI_SRV is set.
To generate a diff of this commit:
cvs rdiff -u -r1.102 -r1.103 src/lib/libc/net/getaddrinfo.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libc/net/getaddrinfo.c
diff -u src/lib/libc/net/getaddrinfo.c:1.102 src/lib/libc/net/getaddrinfo.c:1.103
--- src/lib/libc/net/getaddrinfo.c:1.102 Fri May 3 15:24:52 2013
+++ src/lib/libc/net/getaddrinfo.c Fri May 3 15:31:13 2013
@@ -1,4 +1,4 @@
-/* $NetBSD: getaddrinfo.c,v 1.102 2013/05/03 19:24:52 christos Exp $ */
+/* $NetBSD: getaddrinfo.c,v 1.103 2013/05/03 19:31:13 christos Exp $ */
/* $KAME: getaddrinfo.c,v 1.29 2000/08/31 17:26:57 itojun Exp $ */
/*
@@ -55,7 +55,7 @@
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: getaddrinfo.c,v 1.102 2013/05/03 19:24:52 christos Exp $");
+__RCSID("$NetBSD: getaddrinfo.c,v 1.103 2013/05/03 19:31:13 christos Exp $");
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
@@ -191,6 +191,13 @@ struct res_target {
int n; /* result length */
};
+struct srvinfo {
+ struct srvinfo *next;
+ char name[MAXDNAME];
+ int port, pri, weight;
+};
+
+static int gai_srvok(const char *);
static int str2number(const char *);
static int explore_fqdn(const struct addrinfo *, const char *,
const char *, struct addrinfo **, struct servent_data *);
@@ -217,6 +224,12 @@ static int ip6_str2scopeid(char *, struc
static struct addrinfo *getanswer(const querybuf *, int, const char *, int,
const struct addrinfo *);
static void aisort(struct addrinfo *s, res_state res);
+static struct addrinfo * _dns_query(struct res_target *,
+ const struct addrinfo *, res_state, int);
+static struct addrinfo * _dns_srv_lookup(const char *, const char *,
+ const struct addrinfo *);
+static struct addrinfo * _dns_host_lookup(const char *,
+ const struct addrinfo *);
static int _dns_getaddrinfo(void *, void *, va_list);
static void _sethtent(FILE **);
static void _endhtent(FILE **);
@@ -319,6 +332,58 @@ freeaddrinfo(struct addrinfo *ai)
} while (ai);
}
+/*
+ * We don't want localization to affect us
+ */
+#define PERIOD '.'
+#define hyphenchar(c) ((c) == '-')
+#define periodchar(c) ((c) == PERIOD)
+#define underschar(c) ((c) == '_')
+#define alphachar(c) (((c) >= 'a' && (c) <= 'z') || ((c) >= 'A' && (c) <= 'Z'))
+#define digitchar(c) ((c) >= '0' && (c) <= '9')
+
+#define firstchar(c) (alphachar(c) || digitchar(c) || underschar(c))
+#define lastchar(c) (alphachar(c) || digitchar(c))
+#define middlechar(c) (lastchar(c) || hyphenchar(c))
+
+static int
+gai_srvok(const char *dn)
+{
+ int nch, pch, ch;
+
+ for (pch = PERIOD, nch = ch = *dn++; ch != '\0'; pch = ch, ch = nch) {
+ if (periodchar(ch))
+ continue;
+ if (periodchar(pch)) {
+ if (!firstchar(ch))
+ return 0;
+ } else if (periodchar(nch) || nch == '\0') {
+ if (!lastchar(ch))
+ return 0;
+ } else if (!middlechar(ch))
+ return 0;
+ }
+ return 1;
+}
+
+static in_port_t *
+getport(struct addrinfo *ai) {
+ static in_port_t p;
+
+ switch (ai->ai_family) {
+ case AF_INET:
+ return &((struct sockaddr_in *)(void *)ai->ai_addr)->sin_port;
+#ifdef INET6
+ case AF_INET6:
+ return &((struct sockaddr_in6 *)(void *)ai->ai_addr)->sin6_port;
+#endif
+ default:
+ p = 0;
+ /* XXX: abort()? */
+ return &p;
+ }
+}
+
static int
str2number(const char *p)
{
@@ -589,7 +654,7 @@ explore_fqdn(const struct addrinfo *pai,
return 0;
switch (nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo",
- default_dns_files, hostname, pai)) {
+ default_dns_files, hostname, pai, servname)) {
case NS_TRYAGAIN:
error = EAI_AGAIN;
goto free;
@@ -602,6 +667,9 @@ explore_fqdn(const struct addrinfo *pai,
case NS_SUCCESS:
error = 0;
for (cur = result; cur; cur = cur->ai_next) {
+ /* Check for already filled port. */
+ if (*getport(cur))
+ continue;
GET_PORT(cur, servname, svd);
/* canonname should be filled already */
}
@@ -990,21 +1058,8 @@ get_port(const struct addrinfo *ai, cons
port = sp->s_port;
}
- if (!matchonly) {
- switch (ai->ai_family) {
- case AF_INET:
- ((struct sockaddr_in *)(void *)
- ai->ai_addr)->sin_port = port;
- break;
-#ifdef INET6
- case AF_INET6:
- ((struct sockaddr_in6 *)(void *)
- ai->ai_addr)->sin6_port = port;
- break;
-#endif
- }
- }
-
+ if (!matchonly)
+ *getport(__UNCONST(ai)) = port;
return 0;
}
@@ -1107,7 +1162,7 @@ getanswer(const querybuf *answer, int an
const struct addrinfo *pai)
{
struct addrinfo sentinel, *cur;
- struct addrinfo ai;
+ struct addrinfo ai, *aip;
const struct afd *afd;
char *canonname;
const HEADER *hp;
@@ -1120,6 +1175,8 @@ getanswer(const querybuf *answer, int an
char tbuf[MAXDNAME];
int (*name_ok) (const char *);
char hostbuf[8*1024];
+ int port, pri, weight;
+ struct srvinfo *srvlist, *srv, *csrv;
_DIAGASSERT(answer != NULL);
_DIAGASSERT(qname != NULL);
@@ -1136,6 +1193,9 @@ getanswer(const querybuf *answer, int an
case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/
name_ok = res_hnok;
break;
+ case T_SRV:
+ name_ok = gai_srvok;
+ break;
default:
return NULL; /* XXX should be abort(); */
}
@@ -1175,6 +1235,7 @@ getanswer(const querybuf *answer, int an
}
haveanswer = 0;
had_error = 0;
+ srvlist = NULL;
while (ancount-- > 0 && cp < eom && !had_error) {
n = dn_expand(answer->buf, eom, cp, bp, (int)(ep - bp));
if ((n < 0) || !(*name_ok)(bp)) {
@@ -1277,17 +1338,116 @@ getanswer(const querybuf *answer, int an
cur = cur->ai_next;
cp += n;
break;
+ case T_SRV:
+ /* Add to SRV list. Insertion sort on priority. */
+ pri = _getshort(cp);
+ cp += INT16SZ;
+ weight = _getshort(cp);
+ cp += INT16SZ;
+ port = _getshort(cp);
+ cp += INT16SZ;
+ n = dn_expand(answer->buf, eom, cp, tbuf,
+ (int)sizeof(tbuf));
+ if ((n < 0) || !res_hnok(tbuf)) {
+ had_error++;
+ continue;
+ }
+ cp += n;
+ if (strlen(tbuf) + 1 >= MAXDNAME) {
+ had_error++;
+ continue;
+ }
+ srv = malloc(sizeof(*srv));
+ if (!srv) {
+ had_error++;
+ continue;
+ }
+ strlcpy(srv->name, tbuf, sizeof(srv->name));
+ srv->pri = pri;
+ srv->weight = weight;
+ srv->port = port;
+ /* Weight 0 is sorted before other weights. */
+ if (!srvlist
+ || srv->pri < srvlist->pri
+ || (srv->pri == srvlist->pri &&
+ (!srv->weight || srvlist->weight))) {
+ srv->next = srvlist;
+ srvlist = srv;
+ } else {
+ for (csrv = srvlist;
+ csrv->next && csrv->next->pri <= srv->pri;
+ csrv = csrv->next) {
+ if (csrv->next->pri == srv->pri
+ && (!srv->weight ||
+ csrv->next->weight))
+ break;
+ }
+ srv->next = csrv->next;
+ csrv->next = srv;
+ }
+ continue; /* Don't add to haveanswer yet. */
default:
abort();
}
if (!had_error)
haveanswer++;
}
+
+ if (srvlist) {
+ res_state res;
+ /*
+ * Check for explicit rejection.
+ */
+ if (!srvlist->next && !srvlist->name[0]) {
+ free(srvlist);
+ h_errno = HOST_NOT_FOUND;
+ return NULL;
+ }
+ res = __res_get_state();
+ if (res == NULL) {
+ h_errno = NETDB_INTERNAL;
+ return NULL;
+ }
+
+ while (srvlist) {
+ struct res_target q, q2;
+
+ srv = srvlist;
+ srvlist = srvlist->next;
+
+ /*
+ * Since res_* doesn't give the additional
+ * section, we always look up.
+ */
+ memset(&q, 0, sizeof(q));
+ memset(&q2, 0, sizeof(q2));
+
+ q.name = srv->name;
+ q.qclass = C_IN;
+ q.qtype = T_AAAA;
+ q.next = &q2;
+ q2.name = srv->name;
+ q2.qclass = C_IN;
+ q2.qtype = T_A;
+
+ aip = _dns_query(&q, pai, res, 0);
+
+ if (aip != NULL) {
+ cur->ai_next = aip;
+ while (cur && cur->ai_next) {
+ cur = cur->ai_next;
+ *getport(cur) = htons(srv->port);
+ haveanswer++;
+ }
+ }
+ free(srv);
+ }
+ __res_put_state(res);
+ }
if (haveanswer) {
- if (!canonname)
- (void)get_canonname(pai, sentinel.ai_next, qname);
- else
- (void)get_canonname(pai, sentinel.ai_next, canonname);
+ if (!sentinel.ai_next->ai_canonname)
+ (void)get_canonname(pai, sentinel.ai_next,
+ canonname ? canonname : qname);
h_errno = NETDB_SUCCESS;
return sentinel.ai_next;
}
@@ -1327,117 +1487,251 @@ aisort(struct addrinfo *s, res_state res
s->ai_next = head.ai_next;
}
+static struct addrinfo *
+_dns_query(struct res_target *q, const struct addrinfo *pai,
+ res_state res, int dosearch)
+{
+ struct res_target *q2 = q->next;
+ querybuf *buf, *buf2;
+ struct addrinfo sentinel, *cur, *ai;
+
+#ifdef DNS_DEBUG
+ struct res_target *iter;
+ for (iter = q; iter; iter = iter->next)
+ printf("Query type %d for %s\n", iter->qtype, iter->name);
+#endif
+
+ buf = malloc(sizeof(*buf));
+ if (buf == NULL) {
+ h_errno = NETDB_INTERNAL;
+ return NULL;
+ }
+ buf2 = malloc(sizeof(*buf2));
+ if (buf2 == NULL) {
+ free(buf);
+ h_errno = NETDB_INTERNAL;
+ return NULL;
+ }
+
+ memset(&sentinel, 0, sizeof(sentinel));
+ cur = &sentinel;
+
+ q->answer = buf->buf;
+ q->anslen = sizeof(buf->buf);
+ if (q2) {
+ q2->answer = buf2->buf;
+ q2->anslen = sizeof(buf2->buf);
+ }
+
+ if (dosearch) {
+ if (res_searchN(q->name, q, res) < 0)
+ goto out;
+ } else {
+ if (res_queryN(q->name, q, res) < 0)
+ goto out;
+ }
+
+ ai = getanswer(buf, q->n, q->name, q->qtype, pai);
+ if (ai) {
+ cur->ai_next = ai;
+ while (cur && cur->ai_next)
+ cur = cur->ai_next;
+ }
+ if (q2) {
+ ai = getanswer(buf2, q2->n, q2->name, q2->qtype, pai);
+ if (ai)
+ cur->ai_next = ai;
+ }
+ free(buf);
+ free(buf2);
+ return sentinel.ai_next;
+out:
+ free(buf);
+ free(buf2);
+ return NULL;
+}
+
/*ARGSUSED*/
-static int
-_dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
+static struct addrinfo *
+_dns_srv_lookup(const char *name, const char *servname,
+ const struct addrinfo *pai)
{
- struct addrinfo *ai;
- querybuf *buf, *buf2;
- const char *name;
- const struct addrinfo *pai;
- struct addrinfo sentinel, *cur;
- struct res_target q, q2;
+ static const char * const srvprotos[] = { "tcp", "udp" };
+ static const int srvnottype[] = { SOCK_DGRAM, SOCK_STREAM };
+ static const int nsrvprotos = 2;
+ struct addrinfo sentinel, *cur, *ai;
+ struct servent *serv, sv;
+ struct servent_data svd;
+ struct res_target q;
res_state res;
+ char *tname;
+ int i;
- name = va_arg(ap, char *);
- pai = va_arg(ap, const struct addrinfo *);
+ res = __res_get_state();
+ if (res == NULL)
+ return NULL;
- memset(&q, 0, sizeof(q));
- memset(&q2, 0, sizeof(q2));
+ memset(&svd, 0, sizeof(svd));
memset(&sentinel, 0, sizeof(sentinel));
cur = &sentinel;
- buf = malloc(sizeof(*buf));
- if (buf == NULL) {
- h_errno = NETDB_INTERNAL;
- return NS_NOTFOUND;
- }
- buf2 = malloc(sizeof(*buf2));
- if (buf2 == NULL) {
- free(buf);
- h_errno = NETDB_INTERNAL;
- return NS_NOTFOUND;
+ /*
+ * Iterate over supported SRV protocols.
+ * (currently UDP and TCP only)
+ */
+ for (i = 0; i < nsrvprotos; i++) {
+ /*
+ * Check that the caller didn't specify a hint
+ * which precludes this protocol.
+ */
+ if (pai->ai_socktype == srvnottype[i])
+ continue;
+ /*
+ * If the caller specified a port,
+ * then lookup the database for the
+ * official service name.
+ */
+ serv = getservbyname_r(servname, srvprotos[i], &sv, &svd);
+ if (serv == NULL)
+ continue;
+
+ /*
+ * Construct service DNS name.
+ */
+ if (asprintf(&tname, "_%s._%s.%s", serv->s_name, serv->s_proto,
+ name) < 0)
+ continue;
+
+ memset(&q, 0, sizeof(q));
+ q.name = tname;
+ q.qclass = C_IN;
+ q.qtype = T_SRV;
+
+ /*
+ * Do SRV query.
+ */
+ ai = _dns_query(&q, pai, res, 1);
+ if (ai) {
+ cur->ai_next = ai;
+ while (cur && cur->ai_next)
+ cur = cur->ai_next;
+ }
+ free(tname);
}
+ if (res->nsort)
+ aisort(&sentinel, res);
+
+ __res_put_state(res);
+
+ return sentinel.ai_next;
+}
+
+/*ARGSUSED*/
+static struct addrinfo *
+_dns_host_lookup(const char *name, const struct addrinfo *pai)
+{
+ struct res_target q, q2;
+ struct addrinfo sentinel, *ai;
+ res_state res;
+
+ res = __res_get_state();
+ if (res == NULL)
+ return NULL;
+
+ memset(&q, 0, sizeof(q2));
+ memset(&q2, 0, sizeof(q2));
+
switch (pai->ai_family) {
case AF_UNSPEC:
/* prefer IPv6 */
q.name = name;
q.qclass = C_IN;
q.qtype = T_AAAA;
- q.answer = buf->buf;
- q.anslen = sizeof(buf->buf);
q.next = &q2;
q2.name = name;
q2.qclass = C_IN;
q2.qtype = T_A;
- q2.answer = buf2->buf;
- q2.anslen = sizeof(buf2->buf);
break;
case AF_INET:
q.name = name;
q.qclass = C_IN;
q.qtype = T_A;
- q.answer = buf->buf;
- q.anslen = sizeof(buf->buf);
break;
case AF_INET6:
q.name = name;
q.qclass = C_IN;
q.qtype = T_AAAA;
- q.answer = buf->buf;
- q.anslen = sizeof(buf->buf);
break;
default:
- free(buf);
- free(buf2);
- return NS_UNAVAIL;
+ h_errno = NETDB_INTERNAL;
+ return NULL;
}
- res = __res_get_state();
- if (res == NULL) {
- free(buf);
- free(buf2);
- return NS_NOTFOUND;
- }
+ ai = _dns_query(&q, pai, res, 1);
- if (res_searchN(name, &q, res) < 0) {
- __res_put_state(res);
- free(buf);
- free(buf2);
- return NS_NOTFOUND;
- }
- ai = getanswer(buf, q.n, q.name, q.qtype, pai);
- if (ai) {
- cur->ai_next = ai;
- while (cur && cur->ai_next)
- cur = cur->ai_next;
- }
- if (q.next) {
- ai = getanswer(buf2, q2.n, q2.name, q2.qtype, pai);
- if (ai)
- cur->ai_next = ai;
- }
- free(buf);
- free(buf2);
- if (sentinel.ai_next == NULL) {
- __res_put_state(res);
- switch (h_errno) {
- case HOST_NOT_FOUND:
- return NS_NOTFOUND;
- case TRY_AGAIN:
- return NS_TRYAGAIN;
- default:
- return NS_UNAVAIL;
- }
- }
+ memset(&sentinel, 0, sizeof(sentinel));
+ sentinel.ai_next = ai;
- if (res->nsort)
+ if (ai != NULL && res->nsort)
aisort(&sentinel, res);
__res_put_state(res);
- *((struct addrinfo **)rv) = sentinel.ai_next;
+ return sentinel.ai_next;
+}
+
+/*ARGSUSED*/
+static int
+_dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
+{
+ struct addrinfo *ai = NULL;
+ const char *name, *servname;
+ const struct addrinfo *pai;
+
+ name = va_arg(ap, char *);
+ pai = va_arg(ap, const struct addrinfo *);
+ servname = va_arg(ap, char *);
+
+ /*
+ * Try doing SRV lookup on service first.
+ */
+ if (servname
+#ifdef AI_SRV
+ && (pai->ai_flags & AI_SRV)
+#endif
+ && !(pai->ai_flags & AI_NUMERICSERV)
+ && str2number(servname) == -1) {
+
+#ifdef DNS_DEBUG
+ printf("%s: try SRV lookup\n", __func__);
+#endif
+ ai = _dns_srv_lookup(name, servname, pai);
+ }
+
+ /*
+ * Do lookup on name.
+ */
+ if (ai == NULL) {
+
+#ifdef DNS_DEBUG
+ printf("%s: try HOST lookup\n", __func__);
+#endif
+ ai = _dns_host_lookup(name, pai);
+
+ if (ai == NULL) {
+ switch (h_errno) {
+ case HOST_NOT_FOUND:
+ return NS_NOTFOUND;
+ case TRY_AGAIN:
+ return NS_TRYAGAIN;
+ default:
+ return NS_UNAVAIL;
+ }
+ }
+ }
+
+ *((struct addrinfo **)rv) = ai;
return NS_SUCCESS;
}
@@ -1996,3 +2290,33 @@ res_querydomainN(const char *name, const
}
return res_queryN(longname, target, res);
}
+
+#ifdef TEST
+int
+main(int argc, char *argv[]) {
+ struct addrinfo *ai, *sai;
+ int i, e;
+ char buf[1024];
+
+ for (i = 1; i < argc; i++) {
+ if ((e = getaddrinfo(argv[i], NULL, NULL, &sai)) != 0)
+ warnx("%s: %s", argv[i], gai_strerror(e));
+ for (ai = sai; ai; ai = ai->ai_next) {
+ sockaddr_snprintf(buf, sizeof(buf), "%a", ai->ai_addr);
+ printf("flags=0x%x family=%d socktype=%d protocol=%d "
+ "addrlen=%zu addr=%s canonname=%s next=%p\n",
+ ai->ai_flags,
+ ai->ai_family,
+ ai->ai_socktype,
+ ai->ai_protocol,
+ (size_t)ai->ai_addrlen,
+ buf,
+ ai->ai_canonname,
+ ai->ai_next);
+ }
+ if (sai)
+ freeaddrinfo(sai);
+ }
+ return 0;
+}
+#endif
