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-rw-r--r--src/network/lookup.h11
-rw-r--r--src/network/res_msend.c82
-rw-r--r--src/network/resolvconf.c93
3 files changed, 126 insertions, 60 deletions
diff --git a/src/network/lookup.h b/src/network/lookup.h
index 69419115..0468edbc 100644
--- a/src/network/lookup.h
+++ b/src/network/lookup.h
@@ -2,6 +2,7 @@
#define LOOKUP_H
#include <stdint.h>
+#include <stddef.h>
struct address {
int family;
@@ -15,6 +16,14 @@ struct service {
unsigned char proto, socktype;
};
+#define MAXNS 3
+
+struct resolvconf {
+ struct address ns[MAXNS];
+ unsigned nns, attempts, ndots;
+ unsigned timeout;
+};
+
/* The limit of 48 results is a non-sharp bound on the number of addresses
* that can fit in one 512-byte DNS packet full of v4 results and a second
* packet full of v6 results. Due to headers, the actual limit is lower. */
@@ -25,4 +34,6 @@ int __lookup_serv(struct service buf[static MAXSERVS], const char *name, int pro
int __lookup_name(struct address buf[static MAXADDRS], char canon[static 256], const char *name, int family, int flags);
int __lookup_ipliteral(struct address buf[static 1], const char *name, int family);
+int __get_resolv_conf(struct resolvconf *, char *, size_t);
+
#endif
diff --git a/src/network/res_msend.c b/src/network/res_msend.c
index d0e8e481..0ee914d4 100644
--- a/src/network/res_msend.c
+++ b/src/network/res_msend.c
@@ -31,14 +31,11 @@ int __res_msend(int nqueries, const unsigned char *const *queries,
const int *qlens, unsigned char *const *answers, int *alens, int asize)
{
int fd;
- FILE *f, _f;
- unsigned char _buf[256];
- char line[64], *s, *z;
- int timeout = 5000, attempts = 2, retry_interval, servfail_retry;
+ 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;
@@ -48,65 +45,30 @@ int __res_msend(int nqueries, const unsigned char *const *queries,
int cs;
struct pollfd pfd;
unsigned long t0, t1, t2;
- struct address iplit;
+ struct resolvconf conf;
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) switch (errno) {
- case ENOENT:
- case ENOTDIR:
- case EACCES:
- goto no_resolv_conf;
- default:
- return -1;
- }
- 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;
- }
+ /* Get nameservers & timeout/retry settings from resolv.conf */
+ if (__get_resolv_conf(&conf, 0, 0) < 0) return -1;
+
+ timeout = 1000*conf.timeout;
+ attempts = conf.attempts;
+
+ nns = conf.nns;
+ for (nns=0; nns<conf.nns; nns++) {
+ 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 (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;
- }
- }
- }
- __fclose_ca(f);
-no_resolv_conf:
- 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 */
diff --git a/src/network/resolvconf.c b/src/network/resolvconf.c
new file mode 100644
index 00000000..0743a88f
--- /dev/null
+++ b/src/network/resolvconf.c
@@ -0,0 +1,93 @@
+#include "lookup.h"
+#include "stdio_impl.h"
+#include <ctype.h>
+#include <errno.h>
+#include <string.h>
+#include <netinet/in.h>
+
+int __get_resolv_conf(struct resolvconf *conf, char *search, size_t search_sz)
+{
+ char line[256];
+ unsigned char _buf[256];
+ FILE *f, _f;
+ int nns;
+
+ conf->ndots = 1;
+ conf->timeout = 5;
+ conf->attempts = 2;
+ if (search) *search = 0;
+
+ f = __fopen_rb_ca("/etc/resolv.conf", &_f, _buf, sizeof _buf);
+ if (!f) switch (errno) {
+ case ENOENT:
+ case ENOTDIR:
+ case EACCES:
+ goto no_resolv_conf;
+ default:
+ return -1;
+ }
+
+ while (fgets(line, sizeof line, f)) {
+ char *p, *z;
+ if (!strchr(line, '\n') && !feof(f)) {
+ /* Ignore lines that get truncated rather than
+ * potentially misinterpreting them. */
+ int c;
+ do c = getc(f);
+ while (c != '\n' && c != EOF);
+ continue;
+ }
+ if (!strncmp(line, "options", 7) && isspace(line[7])) {
+ p = strstr(line, "ndots:");
+ if (p && isdigit(p[6])) {
+ p += 6;
+ unsigned long x = strtoul(p, &z, 10);
+ if (z != p) conf->ndots = x > 15 ? 15 : x;
+ }
+ p = strstr(line, "attempts:");
+ if (p && isdigit(p[6])) {
+ p += 6;
+ unsigned long x = strtoul(p, &z, 10);
+ if (z != p) conf->attempts = x > 10 ? 10 : x;
+ }
+ p = strstr(line, "timeout:");
+ if (p && (isdigit(p[8]) || p[8]=='.')) {
+ p += 8;
+ unsigned long x = strtoul(p, &z, 10);
+ if (z != p) conf->timeout = x > 60 ? 60 : x;
+ }
+ continue;
+ }
+ if (!strncmp(line, "nameserver", 10) && isspace(line[10])) {
+ if (nns >= MAXNS) continue;
+ for (p=line+11; isspace(*p); p++);
+ for (z=p; *z && !isspace(*z); z++);
+ *z=0;
+ if (__lookup_ipliteral(conf->ns+nns, p, AF_UNSPEC) > 0)
+ nns++;
+ continue;
+ }
+
+ if (!search) continue;
+ if (strncmp(line, "domain", 6) || strncmp(line, "search", 6)
+ || !isspace(line[6]))
+ continue;
+ for (p=line+7; isspace(*p); p++);
+ size_t l = strlen(p);
+ /* This can never happen anyway with chosen buffer sizes. */
+ if (l >= search_sz) continue;
+ memcpy(search, p, l+1);
+ }
+
+ __fclose_ca(f);
+
+no_resolv_conf:
+ if (!nns) {
+ __lookup_ipliteral(conf->ns, "127.0.0.1", AF_UNSPEC);
+ nns = 1;
+ }
+
+ conf->nns = nns;
+
+ return 0;
+}
generated by cgit v1.2.1 (git 2.18.0) at 2025-10-31 01:07:52 +0000