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dep-curl/tests/server/dnsd.c
Viktor Szakats bb406386d9
curlx_inet_ntop: return CURLcode, drop setting errno 
To simplify and to remove an exception where `errno` was reused to
return a socket error codes on Windows.

The error was used by one call site (`sockaddr2string()` in
`cf-socket.c`), but it was in practice always propagated as
`SOCKEAFNOSUPPORT` to callers.

Also:
- cf-socket: update 3 error messages to show `CURLcode` accordingly.
- if2ip: handle `curlx_inet_ntop()` error in `Curl_if2ip()`.
- dnsd: display `CURLcode` on two errors.

Follow-up to 39dec13ec0 #22170

Closes #22229
2026-08-17 18:41:31 +02:00

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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* SPDX-License-Identifier: curl
*
***************************************************************************/
#include "first.h"
#ifndef __AMIGA__
static int dnsd_wrotepidfile = 0;
static int dnsd_wroteportfile = 0;
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
static uint16_t get16bit(const unsigned char **pkt, size_t *size)
{
const unsigned char *p = *pkt;
(*pkt) += 2;
*size -= 2;
return (uint16_t)((p[0] << 8) | p[1]);
}
#define BLOB_MAX_LEN 4096
struct blob {
uint8_t data[BLOB_MAX_LEN];
size_t dlen;
};
static void blob_reset(struct blob *b)
{
memset(b->data, 0, sizeof(b->data));
b->dlen = 0;
}
static int blob_add(struct blob *b, uint8_t n)
{
if(b->dlen + 1 > BLOB_MAX_LEN)
return 1;
b->data[b->dlen] = n;
b->dlen += 1;
return 0;
}
static int blob_addn(struct blob *b, const uint8_t *data, size_t n)
{
if(b->dlen + n > BLOB_MAX_LEN)
return 1;
memcpy(&b->data[b->dlen], data, n);
b->dlen += n;
return 0;
}
static int blob_add_uint16(struct blob *b, uint16_t n)
{
if(b->dlen + 2 > BLOB_MAX_LEN)
return 1;
b->data[b->dlen] = (n >> 8) & 0xffU;
b->data[b->dlen + 1] = n & 0xffU;
b->dlen += 2;
return 0;
}
static int blob_addchars(struct blob *b, const char *data, size_t n)
{
return blob_addn(b, (const uint8_t *)data, n);
}
static int qname2str(const unsigned char **pkt, size_t *size,
char *name, size_t name_max)
{
unsigned char length;
size_t o = 0;
const unsigned char *p = *pkt;
do {
int i;
length = *p++;
if(*size < length)
/* too long */
return 1;
if(length && o)
name[o++] = '.';
if(o + length >= name_max - 1)
return 1;
for(i = 0; i < length; i++) {
name[o++] = *p++;
}
} while(length);
*size -= (p - *pkt);
*pkt = p;
name[o] = '\0';
return 0;
}
static int blob_add_qname_part(struct blob *b, struct Curl_str *str)
{
size_t dot, skip;
for(dot = 0; dot < str->len; ++dot) {
if(str->str[dot] == '.')
break;
}
if(!dot || (dot > 63)) /* RFC 1035, ch. 3.1 */
return 1;
if(blob_add(b, (uint8_t)dot) ||
(dot && blob_addchars(b, str->str, dot)))
return 1;
skip = dot;
if(dot < str->len)
skip += 1;
str->str += skip;
str->len -= skip;
return 0;
}
static int blob_add_qname(struct blob *b, const struct Curl_str *str)
{
struct Curl_str s = *str;
while(s.len) {
if(s.str[0] == '.') {
if(s.len != 1)
return 1;
break;
}
else {
if(blob_add_qname_part(b, &s))
return 1;
}
}
return blob_add(b, 0);
}
#define QTYPE_A 1
#define QTYPE_AAAA 28
#define QTYPE_HTTPS 0x41
#if 0
#define HTTPS_RR_CODE_MANDATORY 0x00
#endif
#define HTTPS_RR_CODE_ALPN 0x01
#define HTTPS_RR_CODE_NO_DEF_ALPN 0x02
#if 0
#define HTTPS_RR_CODE_PORT 0x03
#define HTTPS_RR_CODE_IPV4 0x04
#define HTTPS_RR_CODE_ECH 0x05
#define HTTPS_RR_CODE_IPV6 0x06
#endif
static const char *type2string(uint16_t qtype)
{
switch(qtype) {
case QTYPE_A:
return "A";
case QTYPE_AAAA:
return "AAAA";
case QTYPE_HTTPS:
return "HTTPS";
}
return "<unknown>";
}
/*
* Handle initial connection protocol.
*
* Return query (qname + type + class), type and id.
*/
static int store_incoming(const char *source, int query_id,
const unsigned char *data, size_t datalen,
unsigned char *qbuf, size_t qbuflen, size_t *qlen,
uint16_t *qtype, uint16_t *idp)
{
FILE *server;
char dumpfile[256];
#if 0
size_t i;
#endif
uint16_t qd;
const uint8_t *qptr;
char name[256];
size_t qsize, size;
*qlen = 0;
*qtype = 0;
*idp = 0;
size = datalen;
if(datalen < 16) {
logmsg("query data size is too small: %ld", (long)datalen);
return -1;
}
snprintf(dumpfile, sizeof(dumpfile), "%s/dnsd.input", logdir);
/* Open request dump file. */
server = curlx_fopen(dumpfile, "ab");
if(!server) {
char errbuf[STRERROR_LEN];
int error = errno;
logmsg("fopen() failed with error (%d) %s",
error, curlx_strerror(error, errbuf, sizeof(errbuf)));
logmsg("[%s] Error opening file '%s'", source, dumpfile);
return -1;
}
/*
1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ID |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|QR| Opcode |AA|TC|RD|RA| Z | RCODE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| QDCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ANCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| NSCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ARCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
*/
*idp = get16bit(&data, &size);
data += 2; /* skip the next 16 bits */
size -= 2;
#if 0
fprintf(server, "[%s] QR: %x\n", source, (*idp & 0x8000) > 15);
fprintf(server, "[%s] OPCODE: %x\n", source, (*idp & 0x7800) >> 11);
fprintf(server, "[%s] TC: %x\n", source, (*idp & 0x200) >> 9);
fprintf(server, "[%s] RD: %x\n", source, (*idp & 0x100) >> 8);
fprintf(server, "[%s] Z: %x\n", source, (*idp & 0x70) >> 4);
fprintf(server, "[%s] RCODE: %x\n", source, (*idp & 0x0f));
#endif
(void)get16bit(&data, &size);
data += 6; /* skip ANCOUNT, NSCOUNT and ARCOUNT */
size -= 6;
/* store pointer and size at the QD point */
qsize = size;
qptr = data;
if(!qname2str(&data, &size, name, sizeof(name))) {
qd = get16bit(&data, &size);
fprintf(server, "QNAME %s QTYPE %s\n", name, type2string(qd));
*qtype = qd;
logmsg("[%d] [%s] Question for '%s' type %x / %s",
query_id, source, name, qd, type2string(qd));
(void)get16bit(&data, &size);
*qlen = qsize - size; /* total size of the query */
if(*qlen > qbuflen) {
logmsg("dnsd: query too large: %lu > %lu",
(unsigned long)*qlen, (unsigned long)qbuflen);
curlx_fclose(server);
return -1;
}
memcpy(qbuf, qptr, *qlen);
}
else
logmsg("Bad input qname");
#if 0
for(i = 0; i < size; i++) {
fprintf(server, "%02d", (unsigned int)data[i]);
}
fprintf(server, "\n");
#endif
curlx_fclose(server);
return 0;
}
static int add_answer(struct blob *body,
const unsigned char *a, size_t alen,
uint16_t qtype)
{
uint8_t prefix[10] = {
0xc0, 0x0c, /* points to the query at this fixed packet index */
0x00, 0x00,
0x00, 0x01, /* QCLASS IN */
0x00, 0x00,
0x0a, 0x14, /* TTL, Time to live: 2580 (43 minutes) */
};
/* QTYPE */
prefix[2] = (unsigned char)(qtype >> 8);
prefix[3] = (unsigned char)(qtype & 0xff);
if(blob_addn(body, prefix, sizeof(prefix)))
return 1;
if((alen > UINT16_MAX) || blob_add_uint16(body, (uint16_t)alen))
return 1;
return blob_addn(body, a, alen);
}
static void fdset_add_sock(fd_set *fds, curl_socket_t sock, int *pmaxfd)
{
FD_SET(sock, fds);
if((int)sock > *pmaxfd)
*pmaxfd = (int)sock;
}
static struct curltime now_plus(timediff_t delta_ms)
{
struct curltime ts = curlx_now();
if(delta_ms > 0) {
int usec = (int)((delta_ms % 1000) * 1000);
ts.tv_sec += (time_t)(delta_ms / 1000);
ts.tv_usec += usec;
if(ts.tv_usec >= 1000000) {
ts.tv_sec++;
ts.tv_usec -= 1000000;
}
}
return ts;
}
static int read_https_alpn_part(struct blob *b, struct Curl_str *str)
{
size_t i, skip;
for(i = 0; i < str->len; ++i) {
if(str->str[i] == ',')
break;
}
if(i >= 256)
return 1;
if(blob_add(b, (uint8_t)i) || blob_addchars(b, str->str, i))
return 1;
skip = i + ((i < str->len) ? 1 : 0);
str->str += skip;
str->len -= skip;
return 0;
}
#ifdef _WIN32
#define SENDTO3 int
#else
#define SENDTO3 size_t
#endif
#define INSTRUCTIONS "dnsd.cmd"
static curlx_struct_stat finfo_last;
static unsigned char ipv4_pref[4];
static unsigned char ipv6_pref[16];
static unsigned char ancount_a;
static unsigned char ancount_aaaa;
static timediff_t a_delay_ms;
static timediff_t aaaa_delay_ms;
static timediff_t https_delay_ms;
static unsigned char rcode_a;
static unsigned char rcode_aaaa;
static struct blob httpsrr;
static int read_https_alpn(struct blob *b, const char **ps)
{
struct Curl_str word;
struct blob tmp;
blob_reset(&tmp);
if(curlx_str_word(ps, &word, UINT16_MAX))
return 1;
while(word.len) {
if(read_https_alpn_part(&tmp, &word))
return 1;
}
if(tmp.dlen > UINT16_MAX)
return 1;
if(blob_add_uint16(b, HTTPS_RR_CODE_ALPN) ||
blob_add_uint16(b, (uint16_t)tmp.dlen) ||
blob_addn(b, tmp.data, tmp.dlen))
return 1;
return 0;
}
static int read_https(struct blob *b, const char *s)
{
struct Curl_str word;
curl_off_t n;
blob_reset(b);
/* Parse a HTTPS textual representation inspired by RFC 9460 */
curlx_str_passblanks(&s);
if(curlx_str_number(&s, &n, UINT16_MAX))
return 1;
if(blob_add_uint16(b, (uint16_t)n))
return 1;
curlx_str_passblanks(&s);
if(curlx_str_word(&s, &word, UINT16_MAX)) {
logmsg("[CONFIG] https: unable to read target qname, input=%s", s);
return 1;
}
if(blob_add_qname(b, &word))
return 1;
while(*s) {
curlx_str_passblanks(&s);
if(!*s)
break;
if(!strncmp("alpn=", s, 5)) {
s += 5;
if(read_https_alpn(b, &s))
return 1;
}
else if(!strncmp("no-default-alpn", s, 15)) {
s += 15;
if(blob_add_uint16(b, HTTPS_RR_CODE_NO_DEF_ALPN) ||
blob_add_uint16(b, 0))
return 1;
}
else
return 1;
}
return 0;
}
static void read_instructions(void)
{
char file[256];
FILE *f;
curlx_struct_stat finfo;
snprintf(file, sizeof(file), "%s/" INSTRUCTIONS, logdir);
if((curlx_stat(file, &finfo) == 0) &&
(finfo.st_mtime == finfo_last.st_mtime) &&
(finfo.st_size == finfo_last.st_size)
#ifndef _WIN32
&& (finfo.st_ino == finfo_last.st_ino)
#endif
#ifdef __APPLE__
&& (finfo.st_mtimespec.tv_nsec == finfo_last.st_mtimespec.tv_nsec)
#elif defined(_POSIX_C_SOURCE)
#if _POSIX_C_SOURCE >= 200809L
&& (finfo.st_mtim.tv_nsec == finfo_last.st_mtim.tv_nsec)
#endif
#endif
) {
/* looks the same as before, skip reading it again */
return;
}
/* reset defaults */
a_delay_ms = aaaa_delay_ms = https_delay_ms = 0;
rcode_a = rcode_aaaa = 0;
blob_reset(&httpsrr);
finfo_last = finfo;
logmsg("[CONFIG] reading from %s", file);
f = curlx_fopen(file, FOPEN_READTEXT);
if(f) {
char buf[256];
ancount_aaaa = ancount_a = 0;
while(fgets(buf, sizeof(buf), f)) {
const char *rtype = NULL;
char *p = strchr(buf, '\n');
if(p) {
int rc;
*p = 0;
if(!strncmp("A: ", buf, 3)) {
rc = curlx_inet_pton(AF_INET, &buf[3], ipv4_pref);
ancount_a = (rc == 1);
rtype = "A";
}
else if(!strncmp("AAAA: ", buf, 6)) {
char *p6 = &buf[6];
if(*p6 == '[') {
char *pt = strchr(p6, ']');
if(pt)
*pt = 0;
p6++;
}
rc = curlx_inet_pton(AF_INET6, p6, ipv6_pref);
ancount_aaaa = (rc == 1);
rtype = "AAAA";
}
else if(!strncmp("HTTPS: ", buf, 7)) {
rc = read_https(&httpsrr, &buf[7]) ? 0 : 1;
rtype = "HTTPS";
}
else if(!strncmp("Delay-A: ", buf, 9)) {
curl_off_t ms;
const char *pms = &buf[9];
rc = 0;
if(!curlx_str_number(&pms, &ms, 100000)) {
a_delay_ms = (timediff_t)ms;
rc = 1;
}
}
else if(!strncmp("Delay-AAAA: ", buf, 12)) {
curl_off_t ms;
const char *pms = &buf[12];
rc = 0;
if(!curlx_str_number(&pms, &ms, 100000)) {
aaaa_delay_ms = (timediff_t)ms;
rc = 1;
}
}
else if(!strncmp("Delay-HTTPS: ", buf, 13)) {
curl_off_t ms;
const char *pms = &buf[13];
rc = 0;
if(!curlx_str_number(&pms, &ms, 100000)) {
https_delay_ms = (timediff_t)ms;
rc = 1;
}
}
else if(!strncmp("Rcode-A: ", buf, 9)) {
curl_off_t code;
const char *pc = &buf[9];
rc = 0;
if(!curlx_str_number(&pc, &code, 15)) {
rcode_a = (unsigned char)code;
rc = 1;
}
}
else if(!strncmp("Rcode-AAAA: ", buf, 12)) {
curl_off_t code;
const char *pc = &buf[12];
rc = 0;
if(!curlx_str_number(&pc, &code, 15)) {
rcode_aaaa = (unsigned char)code;
rc = 1;
}
}
else {
/* accept empty line */
rc = buf[0] ? 0 : 1;
}
if(rc != 1) {
logmsg("[CONFIG] Bad line in %s: '%s'", file, buf);
}
else if(rtype) {
logmsg("[CONFIG] added %s record via '%s'", rtype, buf);
}
}
}
logmsg("[CONFIG] set delays: A=%" FMT_TIMEDIFF_T "ms AAAA=%"
FMT_TIMEDIFF_T "ms HTTPS=%" FMT_TIMEDIFF_T "ms",
a_delay_ms, aaaa_delay_ms, https_delay_ms);
curlx_fclose(f);
}
else
logmsg("[CONFIG] Error opening file '%s'", file);
}
static int last_query_id = -1;
static int dnsd_make_answer(struct blob *blob, int query_id,
const uint8_t *qbuf, size_t qlen,
uint16_t qtype, uint16_t id,
timediff_t *pdelay_ms)
{
int a;
char addrbuf[128]; /* IP address buffer */
uint8_t header[12] = {
0x80, 0xea, /* ID, overwrite */
0x81, 0x80,
/* Flags: 0x8180 Standard query response, No error
1... .... .... .... = Response: Message is a response
.000 0... .... .... = Opcode: Standard query (0)
.... .0.. .... .... = Authoritative: Server is not an authority for
domain
.... ..0. .... .... = Truncated: Message is not truncated
.... ...1 .... .... = Recursion desired: Do query recursively
.... .... 1... .... = Recursion available: Server can do recursive
queries
.... .... .0.. .... = Z: reserved (0)
.... .... ..0. .... = Answer authenticated: Answer/authority portion
was not authenticated by the server
.... .... ...0 .... = Non-authenticated data: Unacceptable
.... .... .... 0000 = Reply code: No error (0)
*/
0x0, 0x1, /* QDCOUNT a single question */
0x0, 0x0, /* ANCOUNT number of answers */
0x0, 0x0, /* NSCOUNT */
0x0, 0x0 /* ARCOUNT */
};
uint16_t ancount = 0;
unsigned char rcode = 0;
CURLcode result;
/* read once per incoming query, which is probably more than one
per test case */
read_instructions();
switch(qtype) {
case QTYPE_A:
ancount = ancount_a;
*pdelay_ms = a_delay_ms;
rcode = rcode_a;
break;
case QTYPE_AAAA:
ancount = ancount_aaaa;
*pdelay_ms = aaaa_delay_ms;
rcode = rcode_aaaa;
break;
case QTYPE_HTTPS:
if(httpsrr.dlen)
ancount = 1;
*pdelay_ms = https_delay_ms;
break;
default:
*pdelay_ms = 0;
}
if(rcode)
ancount = 0;
header[0] = (uint8_t)(id >> 8);
header[1] = (uint8_t)(id & 0xff);
if(rcode) {
header[3] = (uint8_t)((header[3] & 0xf0) | (rcode & 0x0f));
logmsg("[%d] response rcode %u", query_id, (unsigned int)rcode);
}
header[6] = (uint8_t)(ancount >> 8);
header[7] = (uint8_t)(ancount & 0xff);
if(blob_addn(blob, header, sizeof(header)))
return 1;
if(blob_addn(blob, qbuf, qlen)) {
logmsg("unable to handle query of length %zu", qlen);
return 1;
}
switch(qtype) {
case QTYPE_A:
for(a = 0; !rcode && (a < ancount_a); a++) {
const unsigned char *store = ipv4_pref;
if(add_answer(blob, store, sizeof(ipv4_pref), QTYPE_A))
return 1;
result = curlx_inet_ntop(AF_INET, store, addrbuf, sizeof(addrbuf));
logmsg("[%d] response A (%x) '%s' (%d)", query_id,
(unsigned int)QTYPE_A, result ? "?" : addrbuf, (int)result);
}
if(!ancount_a)
logmsg("[%d] response A empty", query_id);
break;
case QTYPE_AAAA:
for(a = 0; !rcode && (a < ancount_aaaa); a++) {
const unsigned char *store = ipv6_pref;
if(add_answer(blob, store, sizeof(ipv6_pref), QTYPE_AAAA))
return 1;
result = curlx_inet_ntop(AF_INET6, store, addrbuf, sizeof(addrbuf));
logmsg("[%d] response AAAA (%x) '%s' (%d)", query_id,
(unsigned int)QTYPE_AAAA, result ? "?" : addrbuf, (int)result);
}
if(!ancount_aaaa)
logmsg("[%d] response AAAA empty", query_id);
break;
case QTYPE_HTTPS:
if(httpsrr.dlen) {
if(add_answer(blob, httpsrr.data, httpsrr.dlen, QTYPE_HTTPS)) {
logmsg("[%d] error adding https %zu response bytes", query_id,
httpsrr.dlen);
return 1;
}
logmsg("[%d] response HTTPS (%x), %zu bytes", query_id,
(unsigned int)QTYPE_HTTPS, httpsrr.dlen);
}
else
logmsg("[%d] response HTTPS, no record", query_id);
break;
}
return 0;
}
struct udp_resp {
struct udp_resp *next;
int query_id;
struct curltime send_ts;
struct sockaddr addr;
curl_socklen_t addrlen;
struct blob body;
};
static struct udp_resp *udp_resp_queue;
static CURLcode send_udp_resp(curl_socket_t sock, struct udp_resp *resp)
{
ssize_t rc;
int sockerr = 0;
do {
rc = sendto(sock, (const void *)resp->body.data, (SENDTO3)resp->body.dlen,
0, &resp->addr, resp->addrlen);
} while((rc < 0) && ((sockerr = SOCKERRNO) == SOCKEINTR));
if(rc < 0) {
char errbuf[STRERROR_LEN];
logmsg("[%d-UDP] failed sending %zu bytes, error: (%d) %s",
resp->query_id, resp->body.dlen,
sockerr, curlx_strerror(sockerr, errbuf, sizeof(errbuf)));
return CURLE_SEND_ERROR;
}
else if(rc != (ssize_t)resp->body.dlen) {
logmsg("[%d-UDP] failed sending %zu bytes, sent: %zd",
resp->query_id, resp->body.dlen, rc);
return CURLE_SEND_ERROR;
}
logmsg("[%d-UDP] sent response", resp->query_id);
return CURLE_OK;
}
static void queue_udp_resp(struct udp_resp *resp)
{
struct udp_resp **panchor = &udp_resp_queue;
while(*panchor) {
timediff_t ms = curlx_ptimediff_ms(&(*panchor)->send_ts, &resp->send_ts);
if(ms > 0) /* resp is to be sent before *panchor */
break;
panchor = &(*panchor)->next;
}
resp->next = *panchor;
*panchor = resp;
}
static timediff_t queue_udp_next_ms(struct curltime *pnow)
{
timediff_t next_ms = 1000;
struct udp_resp *r;
for(r = udp_resp_queue; r; r = r->next) {
timediff_t ms = curlx_ptimediff_ms(&r->send_ts, pnow);
if((ms > 0) && (ms < next_ms))
next_ms = ms;
else if(ms <= 0)
return 0;
}
return next_ms;
}
static void queue_udp_send(curl_socket_t sock, struct curltime *pnow)
{
struct udp_resp **panchor = &udp_resp_queue;
while(*panchor) {
struct udp_resp *resp = *panchor;
timediff_t ms = curlx_ptimediff_ms(&resp->send_ts, pnow);
/* if not due yet, break as response queue is time sorted */
if(ms > 0)
break;
*panchor = resp->next;
send_udp_resp(sock, resp);
curlx_free(resp);
}
}
static void queue_udp_clear(void)
{
while(udp_resp_queue) {
struct udp_resp *resp = udp_resp_queue;
udp_resp_queue = resp->next;
curlx_free(resp);
}
}
/* this is an answer to a question */
static struct udp_resp *udp_resp_create(int query_id,
const struct sockaddr *addr,
curl_socklen_t addrlen,
const unsigned char *qbuf, size_t qlen,
uint16_t qtype, uint16_t id)
{
struct udp_resp *resp;
timediff_t delay_ms = 0;
resp = curlx_calloc(1, sizeof(*resp));
if(!resp)
goto error;
resp->query_id = query_id;
/* on some platforms `curl_socklen_t` is an `int`. Casting might
* wrap this, but then it still has to fit our record size. */
if((size_t)addrlen > sizeof(resp->addr)) {
logmsg("[%d-UDP] unable to handle addrlen of %zu",
query_id, (size_t)addrlen);
goto error;
}
memcpy(&resp->addr, CURL_UNCONST(addr), addrlen);
resp->addrlen = addrlen;
if(dnsd_make_answer(&resp->body, query_id, qbuf, qlen, qtype, id, &delay_ms))
goto error;
resp->send_ts = now_plus(delay_ms);
if(delay_ms > 0)
logmsg("[%d-UDP] delay response by %" FMT_TIMEDIFF_T "ms",
query_id, delay_ms);
return resp;
error:
logmsg("[%d-UDP] failed to create response", query_id);
curlx_free(resp);
return NULL;
}
static int udp_recv_req(curl_socket_t sock)
{
srvr_sockaddr_union_t from;
curl_socklen_t fromlen;
uint8_t inbuffer[1500];
uint8_t qbuf[256]; /* query storage */
size_t qlen = 0; /* query size */
struct udp_resp *resp;
uint16_t qtype = 0, id;
ssize_t n;
int result = 0;
fromlen = sizeof(from);
#ifdef USE_IPV6
if(socket_domain == AF_INET6)
fromlen = sizeof(from.sa6);
else
#endif
fromlen = sizeof(from.sa4);
n = (ssize_t)recvfrom(sock, (char *)inbuffer, sizeof(inbuffer), 0,
&from.sa, &fromlen);
if(got_exit_signal)
goto out;
if(n < 0) {
logmsg("UDP, recvfrom error");
result = 3;
goto out;
}
++last_query_id;
store_incoming("UDP", last_query_id, inbuffer, n,
qbuf, sizeof(qbuf), &qlen, &qtype, &id);
set_advisor_read_lock(loglockfile);
serverlogslocked = 1;
resp = udp_resp_create(last_query_id, &from.sa, fromlen, qbuf,
qlen, qtype, id);
if(!resp)
logmsg("[%d-UDP] error creating response", last_query_id);
else
queue_udp_resp(resp);
out:
return result;
}
#define MAX_DOH_CONNS 512
#define MAX_DOH_INBUF_LEN (8 * 1024)
#define MAX_DOH_OUTBUF_LEN (8 * 1024)
struct doh_conn {
curl_socket_t sock;
int index;
int query_id;
char inbuf[MAX_DOH_INBUF_LEN];
size_t inblen;
size_t inbody_offset;
size_t inbody_len;
char outbuf[MAX_DOH_OUTBUF_LEN];
size_t outblen;
struct curltime send_ts;
BIT(want_recv);
BIT(want_send);
BIT(close_pending);
};
static struct doh_conn doh_conns[MAX_DOH_CONNS];
static void doh_conns_init(void)
{
int i;
for(i = 0; i < MAX_DOH_CONNS; ++i) {
doh_conns[i].sock = CURL_SOCKET_BAD;
doh_conns[i].index = i;
}
}
static int doh_conns_add(curl_socket_t sock)
{
int i;
for(i = 0; i < MAX_DOH_CONNS; ++i) {
if(doh_conns[i].sock == CURL_SOCKET_BAD) {
doh_conns[i].sock = sock;
doh_conns[i].want_recv = TRUE;
logmsg("[x-%d-DOH] accepted new connection, fd=%ld", i, (long)sock);
return 0;
}
}
logmsg("Too many open DoH connections, closing incoming.");
sclose(sock);
return 1;
}
static void doh_conn_close(size_t i)
{
if(i >= MAX_DOH_CONNS)
return;
if(doh_conns[i].sock != CURL_SOCKET_BAD)
sclose(doh_conns[i].sock);
doh_conns[i].sock = CURL_SOCKET_BAD;
doh_conns[i].want_recv = FALSE;
doh_conns[i].want_send = FALSE;
logmsg("[x-%d-DOH] connection closed", (int)i);
}
static void doh_conns_close_all(void)
{
size_t i;
for(i = 0; i < MAX_DOH_CONNS; ++i) {
doh_conn_close(i);
}
}
static void doh_conns_fdsets(fd_set *readfds, fd_set *writefds,
struct curltime *pnow,
int *pmaxfd,
timediff_t *ptimeout_ms)
{
size_t i;
for(i = 0; i < MAX_DOH_CONNS; ++i) {
struct doh_conn *c = &doh_conns[i];
if((c->sock != CURL_SOCKET_BAD)) {
if(!c->want_send && c->outblen) { /* check delayed send */
timediff_t ms = curlx_ptimediff_ms(&c->send_ts, pnow);
if(ms <= 0)
c->want_send = TRUE;
else if((ms < *ptimeout_ms) || !*ptimeout_ms)
*ptimeout_ms = ms;
}
if(c->want_send)
FD_SET(c->sock, writefds);
if(c->want_recv)
FD_SET(c->sock, readfds);
if((FD_ISSET(c->sock, readfds) || FD_ISSET(c->sock, writefds)) &&
(int)c->sock > *pmaxfd)
*pmaxfd = (int)c->sock;
}
}
}
static int doh_conn_send(struct doh_conn *c, struct curltime *pnow)
{
char errbuf[STRERROR_LEN];
ssize_t rc;
int sockerr;
if(c->outblen) {
timediff_t ms = curlx_ptimediff_ms(&c->send_ts, pnow);
size_t n;
if(ms > 0) { /* not due yet */
c->want_send = FALSE;
goto out;
}
rc = swrite(c->sock, c->outbuf, c->outblen);
if(rc < 0) {
sockerr = SOCKERRNO;
if((sockerr == SOCKEINPROGRESS) || SOCK_EAGAIN(sockerr))
return 0;
sockerr = SOCKERRNO;
logmsg("[%d-%d-DOH] swrite(%ld) failed with error (%d) %s",
c->query_id, c->index, (long)c->sock,
sockerr, curlx_strerror(sockerr, errbuf, sizeof(errbuf)));
return 1;
}
n = (size_t)rc;
if(n >= c->outblen) { /* all sent */
c->outblen = 0;
logmsg("[%d-%d-DOH] last response byte sent", c->query_id, c->index);
}
else {
c->outblen -= n;
memmove(c->outbuf, c->outbuf + n, c->outblen);
}
}
out:
if(!c->outblen) {
c->want_send = FALSE;
if(c->close_pending)
return 1;
else {
logmsg("[x-%d-DOH] switching to recv", c->index);
c->want_recv = TRUE;
}
}
return 0;
}
static const char *http_status_descr(int http_status)
{
switch(http_status) {
case 200:
return "Ok";
case 400:
return "Bad Request";
case 404:
return "Not Found";
case 405:
return "Method Not Allowed";
default:
if(http_status < 100)
return "This is wrong";
if(http_status < 200)
return "Just Kidding";
if(http_status < 300)
return "Lgtm";
if(http_status < 400)
return "Follow Me For More Requests";
if(http_status < 500)
return "You were wrong";
return "We did something wrong";
}
}
static int doh_conn_send_err(struct doh_conn *c, int http_status)
{
c->inblen = 0;
c->close_pending = TRUE;
c->want_recv = FALSE;
if(c->outblen) {
logmsg("[%d-%d-DOH] error sending response with %zu bytes still outgoing",
c->query_id, c->index, c->outblen);
return 1;
}
memset(c->outbuf, 0, sizeof(c->outbuf));
snprintf(c->outbuf, sizeof(c->outbuf) - 1,
"HTTP/1.1 %d %s\r\n"
"Content-Length: 0\r\n"
"Connection: close\r\n"
"\r\n",
http_status, http_status_descr(http_status));
c->outblen = strlen(c->outbuf);
c->want_send = TRUE;
logmsg("[%d-%d-DOH] sending HTTP response %d",
c->query_id, c->index, http_status);
return 0;
}
static int doh_conn_send_answer(struct doh_conn *c, struct blob *body,
timediff_t delay_ms)
{
if(c->outblen) { /* Should not happen */
logmsg("[%d-%d-DOH] trying to send an answer with outbuf still having "
"%zu bytes", c->query_id, c->index, c->outblen);
return 1;
}
memset(c->outbuf, 0, sizeof(c->outbuf));
snprintf(c->outbuf, sizeof(c->outbuf) - 1,
"HTTP/1.1 200 %s\r\n"
"Server: curl/test-dnsd\r\n"
"Date: Thu, 06 Aug 2026 08:42:00 GMT\r\n"
"Content-Type: application/dns-message\r\n"
"Content-Length: %ld\r\n"
"\r\n",
http_status_descr(200), (long)body->dlen);
c->outblen = strlen(c->outbuf);
if((c->outblen + body->dlen) > sizeof(c->outbuf)) {
logmsg("[%d-%d-DOH] response size of %zu too large for outbuf",
c->query_id, c->index, c->outblen + body->dlen);
c->outblen = 0;
return 1;
}
memcpy(c->outbuf + c->outblen, body->data, body->dlen);
c->outblen += body->dlen;
c->send_ts = now_plus(delay_ms);
if(delay_ms > 0)
logmsg("[%d-%d-DOH] delay response by %" FMT_TIMEDIFF_T "ms",
c->query_id, c->index, delay_ms);
else
c->want_send = TRUE;
c->want_recv = FALSE;
logmsg("[%d-%d-DOH] sending HTTP response 200",
c->query_id, c->index);
return 0;
}
static int doh_req_parse_headers(const char **pstr,
size_t *pcontent_length,
bool *pcomplete)
{
static const struct Curl_str HD_content_length = {
STRCONST("Content-Length:")
};
static const struct Curl_str HD_content_type = {
STRCONST("Content-Type:")
};
static const struct Curl_str HD_wanted_type = {
STRCONST("application/dns-message")
};
const char *p = *pstr;
bool ct_ok = FALSE;
bool cl_ok = FALSE;
bool eoh = FALSE;
*pcomplete = FALSE;
*pcontent_length = 0;
while(p[0]) {
const char *nl, *start = p;
struct Curl_str hd_name, hd_val;
if((p[0] == '\r') && (p[1] == '\n')) {
p += 2;
eoh = TRUE;
break;
}
nl = strchr(p, '\n');
if(!nl) /* incomplete */
break;
if(curlx_str_word(&p, &hd_name, 1024) ||
curlx_str_singlespace(&p) ||
curlx_str_untilnl(&p, &hd_val, 1024) ||
curlx_str_newline(&p) ||
curlx_str_newline(&p)) {
logmsg("unrecognized request header '%.*s'",
(int)(nl - start), start);
return 1;
}
if(curlx_str_case_equal(&HD_content_type, &hd_name)) {
if(!curlx_str_case_equal(&HD_wanted_type, &hd_val)) {
logmsg("wrong content-type: '%.*s'", (int)hd_val.len, hd_val.str);
return 1;
}
ct_ok = TRUE;
}
else if(curlx_str_case_equal(&HD_content_length, &hd_name)) {
const char *s = hd_val.str;
curl_off_t offt;
if(curlx_str_number(&s, &offt, 4096)) {
logmsg("wrong content-length: '%.*s'", (int)hd_val.len, hd_val.str);
return 1;
}
*pcontent_length = (size_t)offt;
cl_ok = TRUE;
}
else {
/* ignore this header */
}
}
*pstr = p;
if(!eoh)
return 0; /* need more */
if(!ct_ok) {
logmsg("request missing Content-Type");
return 1;
}
if(!cl_ok) {
logmsg("request missing Content-Length");
return 1;
}
*pcomplete = TRUE;
return 0;
}
static int doh_conn_do_req(struct doh_conn *c, bool eos)
{
static const struct Curl_str DOH_PROTO = { STRCONST("HTTP/1.1") };
static const struct Curl_str DOH_METHOD = { STRCONST("POST") };
static const struct Curl_str DOH_PATH = { STRCONST("/") };
const char *first_nl;
bool complete = FALSE;
if(!c->inblen && eos)
return 1;
if(!c->inbody_offset) {
first_nl = strchr(c->inbuf, '\n');
if(first_nl) {
/* This is a poor man's HTTP/1.1 parser and we should rather have
* one in curlx that we can share. */
const char *p = c->inbuf;
struct Curl_str method, path, proto;
if(curlx_str_word(&p, &method, 1024) || curlx_str_singlespace(&p)) {
logmsg("[x-%d-DOH] unrecognized first request line method '%.*s'",
c->index, (int)(first_nl - c->inbuf), c->inbuf);
return 1;
}
if(curlx_str_word(&p, &path, 1024) || curlx_str_singlespace(&p)) {
logmsg("[x-%d-DOH] unrecognized first request line path '%.*s'",
c->index, (int)(first_nl - c->inbuf), c->inbuf);
return 1;
}
if(curlx_str_untilnl(&p, &proto, 1024) ||
curlx_str_newline(&p) ||
curlx_str_newline(&p)) {
logmsg("[x-%d-DOH] unrecognized first request line proto '%.*s'",
c->index, (int)(first_nl - c->inbuf), c->inbuf);
return 1;
}
if(!curlx_str_case_equal(&DOH_PROTO, &proto)) {
logmsg("[x-%d-DOH] unrecognized request protocol '%.*s'",
c->index, (int)proto.len, proto.str);
return 1;
}
if(!curlx_str_case_equal(&DOH_METHOD, &method)) {
logmsg("[x-%d-DOH] unsupported request method '%.*s'",
c->index, (int)method.len, method.str);
return doh_conn_send_err(c, 405);
}
if(!curlx_str_case_equal(&DOH_PATH, &path)) {
logmsg("[x-%d-DOH] request path not fond '%.*s'",
c->index, (int)path.len, path.str);
return doh_conn_send_err(c, 404);
}
if(doh_req_parse_headers(&p, &c->inbody_len, &complete)) {
return doh_conn_send_err(c, 400);
}
/* Looks ok, remember the start of the body bytes */
c->inbody_offset = (p - c->inbuf);
}
if(!complete)
return eos ? 1 : 0; /* want more, error if client close */
}
if(c->inblen >= (c->inbody_offset + c->inbody_len)) {
/* We have all bytes for processing the request */
uint8_t qbuf[256]; /* query storage */
size_t qlen = 0; /* query size */
size_t rlen = c->inbody_offset + c->inbody_len; /* request size */
uint16_t qtype = 0, id;
struct blob blob;
timediff_t delay_ms;
c->query_id = ++last_query_id;
if(store_incoming("DoH", c->query_id, (const uint8_t *)c->inbuf +
c->inbody_offset, c->inbody_len,
qbuf, sizeof(qbuf), &qlen, &qtype, &id)) {
logmsg("[%d-%d-DOH] error storing incoming request",
c->query_id, c->index);
return doh_conn_send_err(c, 400);
}
/* remove handled request from inbuf */
if(rlen >= c->inblen)
c->inblen = 0;
else {
memmove(c->inbuf, c->inbuf + rlen, c->inblen - rlen);
c->inblen -= rlen;
}
c->inbody_len = c->inbody_offset = 0;
memset(&blob, 0, sizeof(blob));
if(dnsd_make_answer(&blob, c->query_id, qbuf, qlen, qtype, id,
&delay_ms)) {
return doh_conn_send_err(c, 500);
}
return doh_conn_send_answer(c, &blob, delay_ms);
}
return 0;
}
static int doh_conn_recv(struct doh_conn *c)
{
char errbuf[STRERROR_LEN];
ssize_t n;
int sockerr;
n = sread(c->sock, c->inbuf + c->inblen, sizeof(c->inbuf) - 1 - c->inblen);
if(n < 0) {
sockerr = SOCKERRNO;
if((sockerr == SOCKEINPROGRESS) || SOCK_EAGAIN(sockerr))
return 0;
sockerr = SOCKERRNO;
logmsg("[x-%d-DOH] sread() failed with error (%d) %s", c->index,
sockerr, curlx_strerror(sockerr, errbuf, sizeof(errbuf)));
return 1;
}
else if(n == 0) {
logmsg("[x-%d-DOH] sread() == 0, client closed connection", c->index);
return doh_conn_do_req(c, TRUE);
}
else {
c->inblen += (size_t)n;
c->inbuf[c->inblen] = 0;
logmsg("[x-%d-DOH] sread() == %zu, processing", c->index, (size_t)n);
return doh_conn_do_req(c, FALSE);
}
}
static int doh_conns_serve(fd_set *readfds, fd_set *writefds)
{
struct curltime now;
size_t i;
for(i = 0; i < MAX_DOH_CONNS; ++i) {
struct doh_conn *c = &doh_conns[i];
if(c->sock != CURL_SOCKET_BAD) {
if(c->want_send && FD_ISSET(c->sock, writefds)) {
now = curlx_now();
if(doh_conn_send(c, &now)) {
doh_conn_close(i);
continue;
}
}
if(c->want_recv && FD_ISSET(c->sock, readfds)) {
if(doh_conn_recv(c)) {
doh_conn_close(i);
continue;
}
}
}
}
return 0;
}
static int test_dnsd(int argc, const char **argv)
{
int arg = 1;
curl_socket_t sock_udp = CURL_SOCKET_BAD;
curl_socket_t sock_tcp_listen = CURL_SOCKET_BAD;
char errbuf[STRERROR_LEN];
int rc, sockerr;
int result = 0;
pidname = ".dnsd.pid";
serverlogfile = "log/dnsd.log";
serverlogslocked = 0;
server_port = 9123; /* UDP */
socket_domain = AF_INET;
while(argc > arg) {
const char *opt;
curl_off_t num;
if(!strcmp("--verbose", argv[arg])) {
arg++;
/* nothing yet */
}
else if(!strcmp("--version", argv[arg])) {
printf("dnsd IPv4%s\n",
#ifdef USE_IPV6
"/IPv6"
#else
""
#endif
);
return 0;
}
else if(!strcmp("--pidfile", argv[arg])) {
arg++;
if(argc > arg)
pidname = argv[arg++];
}
else if(!strcmp("--portfile", argv[arg])) {
arg++;
if(argc > arg)
portname = argv[arg++];
}
else if(!strcmp("--logfile", argv[arg])) {
arg++;
if(argc > arg)
serverlogfile = argv[arg++];
}
else if(!strcmp("--logdir", argv[arg])) {
arg++;
if(argc > arg)
logdir = argv[arg++];
}
else if(!strcmp("--ipv4", argv[arg])) {
socket_type = "IPv4";
socket_domain = AF_INET;
arg++;
}
else if(!strcmp("--ipv6", argv[arg])) {
#ifdef USE_IPV6
socket_type = "IPv6";
socket_domain = AF_INET6;
#endif
arg++;
}
else if(!strcmp("--port", argv[arg])) {
arg++;
if(argc > arg) {
opt = argv[arg];
if(!curlx_str_number(&opt, &num, 0xffff))
server_port = (uint16_t)num;
arg++;
}
}
else {
if(argv[arg])
fprintf(stderr, "unknown option: %s\n", argv[arg]);
puts("Usage: dnsd [option]\n"
" --version\n"
" --logfile [file]\n"
" --logdir [directory]\n"
" --pidfile [file]\n"
" --portfile [file]\n"
" --ipv4\n"
" --ipv6\n"
" --port [port]\n");
return 0;
}
}
snprintf(loglockfile, sizeof(loglockfile), "%s/%s/dnsd-%s.lock",
logdir, SERVERLOGS_LOCKDIR, socket_type);
install_signal_handlers(FALSE);
result = open_stream_sock(&sock_tcp_listen, &server_port);
if(result)
goto dnsd_cleanup;
doh_conns_init();
result = open_udp_sock(&sock_udp, &server_port);
if(result)
goto dnsd_cleanup;
dnsd_wrotepidfile = write_pidfile(pidname);
if(!dnsd_wrotepidfile) {
result = 1;
goto dnsd_cleanup;
}
if(portname) {
dnsd_wroteportfile = write_portfile(portname, server_port);
if(!dnsd_wroteportfile) {
result = 1;
goto dnsd_cleanup;
}
}
/* start accepting connections */
if(listen(sock_tcp_listen, 50)) {
sockerr = SOCKERRNO;
logmsg("listen() failed with error (%d) %s",
sockerr, curlx_strerror(sockerr, errbuf, sizeof(errbuf)));
result = 1;
goto dnsd_cleanup;
}
logmsg("Running %s on port UDP+TCP/%u", socket_type, server_port);
curlx_nonblock(sock_udp, TRUE);
curlx_nonblock(sock_tcp_listen, TRUE);
for(;;) {
timediff_t timeout_ms = 0;
fd_set readfds, writefds;
struct timeval tv;
int maxfd = 0;
struct curltime now = curlx_now();
FD_ZERO(&readfds);
fdset_add_sock(&readfds, sock_udp, &maxfd);
fdset_add_sock(&readfds, sock_tcp_listen, &maxfd);
FD_ZERO(&writefds);
timeout_ms = queue_udp_next_ms(&now);
if(!timeout_ms)
fdset_add_sock(&writefds, sock_udp, &maxfd);
doh_conns_fdsets(&readfds, &writefds, &now, &maxfd, &timeout_ms);
if(!timeout_ms || (timeout_ms > 100))
timeout_ms = 100;
rc = select(maxfd + 1, &readfds, &writefds, NULL,
curlx_mstotv(&tv, timeout_ms));
if(rc == -1) {
logmsg("error %d returned by select()", SOCKERRNO);
}
else if(!rc) { /* timeout */
continue;
}
if(FD_ISSET(sock_udp, &writefds)) {
now = curlx_now();
queue_udp_send(sock_udp, &now);
}
if(FD_ISSET(sock_udp, &readfds)) {
result = udp_recv_req(sock_udp);
if(result)
break;
}
result = doh_conns_serve(&readfds, &writefds);
if(result)
break;
if(FD_ISSET(sock_tcp_listen, &readfds)) {
/* Service all queued connections */
curl_socket_t sock_conn;
while(TRUE) {
sock_conn = accept_connection(sock_tcp_listen);
if(!sock_conn) /* no more connections to accept */
break;
if(sock_conn == CURL_SOCKET_BAD)
goto dnsd_cleanup;
doh_conns_add(sock_conn);
}
}
if(got_exit_signal)
break;
if(serverlogslocked) {
serverlogslocked = 0;
clear_advisor_read_lock(loglockfile);
}
}
dnsd_cleanup:
if(sock_udp != CURL_SOCKET_BAD)
sclose(sock_udp);
if(sock_tcp_listen != CURL_SOCKET_BAD)
sclose(sock_tcp_listen);
doh_conns_close_all();
if(got_exit_signal)
logmsg("signalled to die");
if(dnsd_wrotepidfile)
unlink(pidname);
if(dnsd_wroteportfile)
unlink(portname);
if(serverlogslocked) {
serverlogslocked = 0;
clear_advisor_read_lock(loglockfile);
}
queue_udp_clear();
restore_signal_handlers(FALSE);
return result;
}
#else
static int test_dnsd(int argc, const char **argv)
{
(void)argc;
(void)argv;
fprintf(stderr, "dnsd on AmigaOS is unsupported\n");
return 1;
}
#endif
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