Mirrors/libwebsockets
1
0
Fork 0
mirror of https://github.com/warmcat/libwebsockets.git synced 2025-03-30 00:00:16 +01:00
Code Issues Releases Wiki Activity

asyncdns: also consult system hosts file

Browse source 
We should also consult any system hosts file if available as part of the
async dns prep, same as we check for numeric IPs.
This commit is contained in:
Andy Green 2022-04-04 09:02:40 +01:00
parent 047fb7bb21
commit b43866ffeb
1 changed files with 94 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

107
lib/system/async-dns/async-dns.c
View file

@ -838,6 +838,91 @@ lws_async_dns_get_new_tid(struct lws_context *context, lws_adns_q_t *q)
return -1;
}
#if !defined(LWS_PLAT_OPTEE) && !defined(LWS_PLAT_FREERTOS)
/*
* Search /etc/hosts or similar for the DNS name
*/
int
lws_adns_scan_hostsfile(const char *name, uint8_t *ads, size_t adslen)
{
char had_ads = 0, buf[128], finalized = 0;
int fd, ret = 0, l = 0, ol = -1;
size_t nl = strlen(name);
struct lws_tokenize ts;
#if defined(WIN32)
int s;
fd = _open("C:\\Windows\\System32\\Drivers\\etc\\hosts", LWS_O_RDONLY);
#else
ssize_t s;
fd = open("/etc/hosts", LWS_O_RDONLY);
#endif
if (fd < 0)
return 0;
memset(&ts, 0, sizeof(ts));
ts.flags = LWS_TOKENIZE_F_EXPECT_MORE | LWS_TOKENIZE_F_MINUS_NONTERM |
LWS_TOKENIZE_F_DOT_NONTERM | LWS_TOKENIZE_F_NO_FLOATS |
LWS_TOKENIZE_F_NO_INTEGERS | LWS_TOKENIZE_F_HASH_COMMENT |
LWS_TOKENIZE_F_COLON_NONTERM;
do {
#if defined(WIN32)
s = _read(fd, buf, sizeof(buf) - 1);
#else
s = read(fd, buf, sizeof(buf) - 1);
#endif
if (s <= 0) {
finalized = 1;
ts.flags = (uint16_t)(ts.flags & (~LWS_TOKENIZE_F_EXPECT_MORE));
s = 0;
}
ts.start = (char *)buf;
ts.len = (size_t)s;
do {
ts.e = (int8_t)lws_tokenize(&ts);
if (ts.e == LWS_TOKZE_WANT_READ)
break;
if (ts.effline != ol) {
had_ads = 0;
ol = ts.effline;
}
if (ts.e == LWS_TOKZE_TOKEN && had_ads && l &&
nl == ts.token_len &&
!memcmp(name, ts.token, ts.token_len)) {
/* it's a hit */
ret = (int)l;
break;
}
if (ts.e == LWS_TOKZE_TOKEN && !had_ads && ts.token_len < 50) {
/* we're getting an ipv4 or ipv6 numads */
l = lws_parse_numeric_address(ts.token, ads, adslen);
had_ads = 1;
}
} while (ts.e > 0); /* no error yet */
} while (!ret && !finalized); /* no match yet */
#if defined(WIN32)
_close(fd);
#else
close(fd);
#endif
return ret;
}
#endif
uint16_t
lws_adns_get_tid(struct lws_adns_q *q)
@ -886,19 +971,6 @@ lws_async_dns_query(struct lws_context *context, int tsi, const char *name,
if (nlen >= DNS_MAX - 1)
goto failed;
/*
* we magically know 'localhost' and 'localhost6' if IPv6, this is a
* sort of canned /etc/hosts
*/
if (!strcmp(name, "localhost"))
name = "127.0.0.1";
#if defined(LWS_WITH_IPV6)
if (!strcmp(name, "localhost6"))
name = "::1";
#endif
if (wsi) {
if (!lws_dll2_is_detached(&wsi->adns)) {
lwsl_cx_err(context, "%s already bound to query %p",
@ -942,6 +1014,15 @@ lws_async_dns_query(struct lws_context *context, int tsi, const char *name,
*/
m = lws_parse_numeric_address(name, ads, sizeof(ads));
#if !defined(LWS_PLAT_OPTEE) && !defined(LWS_PLAT_FREERTOS)
if (m < 4)
/*
* Not directly numeric... look through /etc/hosts
*/
m = lws_adns_scan_hostsfile(name, ads, sizeof(ads));
#endif
if (m == 4
#if defined(LWS_WITH_IPV6)
|| m == 16