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Implemented resolver to replace sock_srv_lookup()

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This commit is contained in:
Dmitry Podgorny
2015-10-14 18:48:55 +03:00
parent 714b2f9c03
commit b7e308d057
11 changed files with 910 additions and 699 deletions
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679
src/sock.c
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@@ -21,7 +21,6 @@
#ifdef _WIN32
#include <winsock2.h>
#include <ws2tcpip.h>
#include <windns.h>
#include <Iphlpapi.h>
#else
#include <errno.h>
@@ -30,11 +29,6 @@
#include <netinet/in.h>
#include <netdb.h>
#include <fcntl.h>
#include <arpa/nameser.h>
#ifdef HAVE_ARPA_NAMESER_COMPAT_H
#include <arpa/nameser_compat.h>
#endif
#include <resolv.h>
#endif
#include "sock.h"
@@ -73,7 +67,7 @@ static int _in_progress(int error)
#endif
}
sock_t sock_connect(const char * const host, const unsigned int port)
sock_t sock_connect(const char * const host, const unsigned short port)
{
sock_t sock;
char service[6];
@@ -205,674 +199,3 @@ int sock_connect_error(const sock_t sock)
return sock_error();
}
struct dnsquery_header
{
unsigned short id;
unsigned char qr;
unsigned char opcode;
unsigned char aa;
unsigned char tc;
unsigned char rd;
unsigned char ra;
unsigned char z;
unsigned char rcode;
unsigned short qdcount;
unsigned short ancount;
unsigned short nscount;
unsigned short arcount;
};
struct dnsquery_question
{
char qname[1024];
unsigned short qtype;
unsigned short qclass;
};
struct dnsquery_srvrdata
{
unsigned short priority;
unsigned short weight;
unsigned short port;
char target[1024];
};
struct dnsquery_resourcerecord
{
char name[1024];
unsigned short type;
unsigned short _class;
unsigned int ttl;
unsigned short rdlength;
struct dnsquery_srvrdata rdata;
};
static void netbuf_get_32bitnum(unsigned char *buf, int buflen, int *offset, unsigned int *num)
{
unsigned char *start = buf + *offset;
unsigned char *p = start;
*num = 0;
/* assuming big endian */
*num |= (*p++) << 24;
*num |= (*p++) << 16;
*num |= (*p++) << 8;
*num |= (*p++);
*offset += 4;
}
static void netbuf_get_16bitnum(unsigned char *buf, int buflen, int *offset, unsigned short *num)
{
unsigned char *start = buf + *offset;
unsigned char *p = start;
*num = 0;
/* assuming big endian */
*num |= (*p++) << 8;
*num |= (*p++);
*offset += 2;
}
static int netbuf_get_domain_name(unsigned char *buf, int buflen, int *offset, char *namebuf, int namebuflen)
{
unsigned char *start = buf + *offset;
unsigned char *p, *p2;
int *curroffset = offset;
int len = 0;
*namebuf = '\0';
/* measure length */
p = start;
while (*p)
{
if ((*p & 0xC0) == 0xC0)
{
int newoffset = 0;
newoffset |= (*p++ & 0x3F) << 8;
newoffset |= *p++;
p = buf + newoffset;
}
else
{
len += *p;
p += *p + 1;
}
}
if (namebuflen < len)
{
return len;
}
/* actually copy in name */
p = start;
p2 = (unsigned char *)namebuf;
while (*p)
{
if ((*p & 0xC0) == 0xC0)
{
int newoffset = 0;
newoffset |= (*p++ & 0x3F) << 8;
newoffset |= *p++;
if (curroffset)
{
*curroffset += (int)(p - start);
curroffset = NULL;
}
p = buf + newoffset;
}
else
{
int i, partlen;
if (*namebuf != '\0')
{
*p2++ = '.';
}
partlen = *p++;
for (i=0; i < partlen; i++)
{
*p2++ = *p++;
}
}
}
if (curroffset)
{
p++;
*curroffset += (int)(p - start);
curroffset = NULL;
}
*p2 = '\0';
return 0;
}
static void netbuf_get_dnsquery_header(unsigned char *buf, int buflen, int *offset, struct dnsquery_header *header)
{
unsigned char *p;
netbuf_get_16bitnum(buf, buflen, offset, &(header->id));
p = buf + *offset;
header->qr = (*p >> 7) & 0x01;
header->opcode = (*p >> 3) & 0x0F;
header->aa = (*p >> 2) & 0x01;
header->tc = (*p >> 1) & 0x01;
header->rd = (*p) & 0x01;
p++;
header->ra = (*p >> 7) & 0x01;
header->z = (*p >> 4) & 0x07;
header->rcode = (*p) & 0x0F;
p++;
*offset += 2;
netbuf_get_16bitnum(buf, buflen, offset, &(header->qdcount));
netbuf_get_16bitnum(buf, buflen, offset, &(header->ancount));
netbuf_get_16bitnum(buf, buflen, offset, &(header->nscount));
netbuf_get_16bitnum(buf, buflen, offset, &(header->arcount));
}
static void netbuf_get_dnsquery_question(unsigned char *buf, int buflen, int *offset, struct dnsquery_question *question)
{
netbuf_get_domain_name(buf, buflen, offset, question->qname, 1024);
netbuf_get_16bitnum(buf, buflen, offset, &(question->qtype));
netbuf_get_16bitnum(buf, buflen, offset, &(question->qclass));
}
static void netbuf_get_dnsquery_srvrdata(unsigned char *buf, int buflen, int *offset, struct dnsquery_srvrdata *srvrdata)
{
netbuf_get_16bitnum(buf, buflen, offset, &(srvrdata->priority));
netbuf_get_16bitnum(buf, buflen, offset, &(srvrdata->weight));
netbuf_get_16bitnum(buf, buflen, offset, &(srvrdata->port));
netbuf_get_domain_name(buf, buflen, offset, srvrdata->target, 1024);
}
static void netbuf_get_dnsquery_resourcerecord(unsigned char *buf, int buflen, int *offset, struct dnsquery_resourcerecord *rr)
{
netbuf_get_domain_name(buf, buflen, offset, rr->name, 1024);
netbuf_get_16bitnum(buf, buflen, offset, &(rr->type));
netbuf_get_16bitnum(buf, buflen, offset, &(rr->_class));
netbuf_get_32bitnum(buf, buflen, offset, &(rr->ttl));
netbuf_get_16bitnum(buf, buflen, offset, &(rr->rdlength));
if (rr->type == 33) /* SRV */
{
int newoffset = *offset;
netbuf_get_dnsquery_srvrdata(buf, buflen, &newoffset, &(rr->rdata));
}
*offset += rr->rdlength;
}
#ifdef _WIN32
static void netbuf_add_16bitnum(unsigned char *buf, int buflen, int *offset, unsigned short num)
{
unsigned char *start = buf + *offset;
unsigned char *p = start;
/* assuming big endian */
*p++ = (num >> 8) & 0xff;
*p++ = (num) & 0xff;
*offset += 2;
}
static void netbuf_add_domain_name(unsigned char *buf, int buflen, int *offset,
char *name)
{
unsigned char *start = buf + *offset;
unsigned char *p = start;
unsigned char *wordstart, *wordend;
wordstart = (unsigned char *)name;
while (*wordstart)
{
int len;
wordend = wordstart;
while (*wordend && *wordend != '.')
{
wordend++;
}
len = (int)(wordend - wordstart);
if (len > 0x3F)
{
len = 0x3F;
}
*p++ = len;
while (wordstart != wordend)
{
*p++ = *wordstart++;
}
if (*wordstart == '.')
{
wordstart++;
}
}
*p++ = '\0';
*offset += p - start;
}
static void netbuf_add_dnsquery_header(unsigned char *buf, int buflen, int *offset, struct dnsquery_header *header)
{
unsigned char *p;
netbuf_add_16bitnum(buf, buflen, offset, header->id);
p = buf + *offset;
*p++ = ((header->qr & 0x01) << 7)
| ((header->opcode & 0x0F) << 3)
| ((header->aa & 0x01) << 2)
| ((header->tc & 0x01) << 1)
| ((header->rd & 0x01));
*p++ = ((header->ra & 0x01) << 7)
| ((header->z & 0x07) << 4)
| ((header->rcode & 0x0F));
*offset += 2;
netbuf_add_16bitnum(buf, buflen, offset, header->qdcount);
netbuf_add_16bitnum(buf, buflen, offset, header->ancount);
netbuf_add_16bitnum(buf, buflen, offset, header->nscount);
netbuf_add_16bitnum(buf, buflen, offset, header->arcount);
}
static void netbuf_add_dnsquery_question(unsigned char *buf, int buflen, int *offset, struct dnsquery_question *question)
{
netbuf_add_domain_name(buf, buflen, offset, question->qname);
netbuf_add_16bitnum(buf, buflen, offset, question->qtype);
netbuf_add_16bitnum(buf, buflen, offset, question->qclass);
}
#endif /* _WIN32 */
int sock_srv_lookup(const char *service, const char *proto,
const char *domain, char *resulttarget,
int resulttargetlength, int *resultport)
{
int set = 0;
char fulldomain[2048];
xmpp_snprintf(fulldomain, sizeof(fulldomain),
"_%s._%s.%s", service, proto, domain);
#ifdef _WIN32
/* try using dnsapi first */
if (!set)
{
HINSTANCE hdnsapi = NULL;
DNS_STATUS (WINAPI * pDnsQuery_A)(PCSTR, WORD, DWORD, PIP4_ARRAY, PDNS_RECORD*, PVOID*);
void (WINAPI * pDnsRecordListFree)(PDNS_RECORD, DNS_FREE_TYPE);
if (hdnsapi = LoadLibrary("dnsapi.dll")) {
pDnsQuery_A = (void *)GetProcAddress(hdnsapi, "DnsQuery_A");
pDnsRecordListFree = (void *)GetProcAddress(hdnsapi, "DnsRecordListFree");
if (pDnsQuery_A && pDnsRecordListFree) {
PDNS_RECORD dnsrecords = NULL;
DNS_STATUS error;
error = pDnsQuery_A(fulldomain, DNS_TYPE_SRV, DNS_QUERY_STANDARD, NULL, &dnsrecords, NULL);
if (error == 0) {
PDNS_RECORD current = dnsrecords;
while (current) {
if (current->wType == DNS_TYPE_SRV) {
xmpp_snprintf(resulttarget, resulttargetlength, "%s", current->Data.Srv.pNameTarget);
*resultport = current->Data.Srv.wPort;
set = 1;
current = NULL;
} else {
current = current->pNext;
}
}
}
pDnsRecordListFree(dnsrecords, DnsFreeRecordList);
}
FreeLibrary(hdnsapi);
}
}
/* if dnsapi didn't work/isn't there, try querying the dns server manually */
if (!set)
{
unsigned char buf[65536];
struct dnsquery_header header;
struct dnsquery_question question;
int offset = 0;
int addrlen;
sock_t sock;
struct sockaddr_in dnsaddr;
char dnsserverips[16][256];
int numdnsservers = 0;
int j;
/* Try getting the DNS server ips from GetNetworkParams() in iphlpapi first */
if (!numdnsservers)
{
HINSTANCE hiphlpapi = NULL;
DWORD (WINAPI * pGetNetworkParams)(PFIXED_INFO, PULONG);
if (hiphlpapi = LoadLibrary("Iphlpapi.dll"))
{
pGetNetworkParams = (void *)GetProcAddress(hiphlpapi, "GetNetworkParams");
if (pGetNetworkParams)
{
FIXED_INFO *fi;
ULONG len;
DWORD error;
char buffer[65535];
len = 65535;
fi = buffer;
if ((error = pGetNetworkParams(fi, &len)) == ERROR_SUCCESS)
{
IP_ADDR_STRING *pias = &(fi->DnsServerList);
while (pias && numdnsservers < 16)
{
strcpy(dnsserverips[numdnsservers++], pias->IpAddress.String);
pias = pias->Next;
}
}
}
}
FreeLibrary(hiphlpapi);
}
/* Next, try getting the DNS server ips from the registry */
if (!numdnsservers)
{
HKEY search;
LONG error;
error = RegOpenKeyEx(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters", 0, KEY_READ, &search);
if (error != ERROR_SUCCESS)
{
error = RegOpenKeyEx(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\Services\\VxD\\MSTCP", 0, KEY_READ, &search);
}
if (error == ERROR_SUCCESS)
{
char name[512];
DWORD len = 512;
error = RegQueryValueEx(search, "NameServer", NULL, NULL, (LPBYTE)name, &len);
if (error != ERROR_SUCCESS)
{
error = RegQueryValueEx(search, "DhcpNameServer", NULL, NULL, (LPBYTE)name, &len);
}
if (error == ERROR_SUCCESS)
{
char *parse = "0123456789.", *start, *end;
start = name;
end = name;
name[len] = '\0';
while (*start && numdnsservers < 16)
{
while (strchr(parse, *end))
{
end++;
}
strncpy(dnsserverips[numdnsservers++], start, end - start);
while (*end && !strchr(parse, *end))
{
end++;
}
start = end;
}
}
}
RegCloseKey(search);
}
if (!numdnsservers)
{
HKEY searchlist;
LONG error;
error = RegOpenKeyEx(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters\\Interfaces", 0, KEY_READ, &searchlist);
if (error == ERROR_SUCCESS)
{
unsigned int i;
DWORD numinterfaces = 0;
RegQueryInfoKey(searchlist, NULL, NULL, NULL, &numinterfaces, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
for (i = 0; i < numinterfaces; i++)
{
char name[512];
DWORD len = 512;
HKEY searchentry;
RegEnumKeyEx(searchlist, i, (LPTSTR)name, &len, NULL, NULL, NULL, NULL);
if (RegOpenKeyEx(searchlist, name, 0, KEY_READ, &searchentry) == ERROR_SUCCESS)
{
if (RegQueryValueEx(searchentry, "DhcpNameServer", NULL, NULL, (LPBYTE)name, &len) == ERROR_SUCCESS)
{
char *parse = "0123456789.", *start, *end;
start = name;
end = name;
name[len] = '\0';
while (*start && numdnsservers < 16)
{
while (strchr(parse, *end))
{
end++;
}
strncpy(dnsserverips[numdnsservers++], start, end - start);
while (*end && !strchr(parse, *end))
{
end++;
}
start = end;
}
}
else if (RegQueryValueEx(searchentry, "NameServer", NULL, NULL, (LPBYTE)name, &len) == ERROR_SUCCESS)
{
char *parse = "0123456789.", *start, *end;
start = name;
end = name;
name[len] = '\0';
while (*start && numdnsservers < 16)
{
while (strchr(parse, *end))
{
end++;
}
strncpy(dnsserverips[numdnsservers++], start, end - start);
while (*end && !strchr(parse, *end))
{
end++;
}
start = end;
}
}
RegCloseKey(searchentry);
}
}
RegCloseKey(searchlist);
}
}
/* If we have a DNS server, use it */
if (numdnsservers)
{
ULONG nonblocking = 1;
int i;
int insize;
memset(&header, 0, sizeof(header));
header.id = 12345; /* FIXME: Get a better id here */
header.rd = 1;
header.qdcount = 1;
netbuf_add_dnsquery_header(buf, 65536, &offset, &header);
memset(&question, 0, sizeof(question));
strncpy(question.qname, fulldomain, 1024);
question.qtype = 33; /* SRV */
question.qclass = 1; /* INTERNET! */
netbuf_add_dnsquery_question(buf, 65536, &offset, &question);
insize = 0;
for (i = 0; i < numdnsservers && insize <= 0; i++)
{
sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
ioctlsocket(sock, FIONBIO, &nonblocking);
memset(&dnsaddr, 0, sizeof(dnsaddr));
dnsaddr.sin_family = AF_INET;
dnsaddr.sin_port = htons(53);
dnsaddr.sin_addr.s_addr = inet_addr(dnsserverips[i]);
addrlen = sizeof(dnsaddr);
sendto(sock, (char *)buf, offset, 0, (struct sockaddr *)&dnsaddr, addrlen);
for (j = 0; j < 50; j++)
{
insize = recvfrom(sock, (char *)buf, 65536, 0, (struct sockaddr *)&dnsaddr, &addrlen);
if (insize == SOCKET_ERROR)
{
if (sock_error() == WSAEWOULDBLOCK)
{
Sleep(100);
}
else
{
break;
}
}
else
{
break;
}
}
closesocket(sock);
}
offset = insize;
if (offset > 0)
{
int len = offset;
int i;
struct dnsquery_header header;
struct dnsquery_question question;
struct dnsquery_resourcerecord rr;
offset = 0;
netbuf_get_dnsquery_header(buf, 65536, &offset, &header);
for (i = 0; i < header.qdcount; i++)
{
netbuf_get_dnsquery_question(buf, 65536, &offset, &question);
}
for (i = 0; i < header.ancount; i++)
{
netbuf_get_dnsquery_resourcerecord(buf, 65536, &offset, &rr);
if (rr.type == 33)
{
struct dnsquery_srvrdata *srvrdata = &(rr.rdata);
xmpp_snprintf(resulttarget, resulttargetlength, "%s", srvrdata->target);
*resultport = srvrdata->port;
set = 1;
}
}
for (i = 0; i < header.ancount; i++)
{
netbuf_get_dnsquery_resourcerecord(buf, 65536, &offset, &rr);
}
}
}
}
#else
if (!set) {
unsigned char buf[65535];
unsigned short min;
int len;
if ((len = res_query(fulldomain, C_IN, T_SRV, buf, 65535)) > 0) {
int offset;
int i;
struct dnsquery_header header;
struct dnsquery_question question;
struct dnsquery_resourcerecord rr;
offset = 0;
netbuf_get_dnsquery_header(buf, 65536, &offset, &header);
for (i = 0; i < header.qdcount; i++) {
netbuf_get_dnsquery_question(buf, 65536, &offset, &question);
}
min = 65535;
for (i = 0; i < header.ancount; i++) {
netbuf_get_dnsquery_resourcerecord(buf, 65536, &offset, &rr);
if (rr.type == 33) {
struct dnsquery_srvrdata *srvrdata = &(rr.rdata);
if (srvrdata->priority < min || !set) {
xmpp_snprintf(resulttarget, resulttargetlength, "%s",
srvrdata->target);
*resultport = srvrdata->port;
set = 1;
min = srvrdata->priority;
}
}
}
}
}
#endif
return set;
}