[PATCH 0/4] Create DNS API and wire it to dhcp and libc DNS resolver

[Benoît Canet]

This patchset is written to close issue #9.
Tests can be done before/after the patchset with tst-dns-resolver.so

Best regards

Benoît

Benoît Canet (4):
dns: add core/dns API
dhcp: wire dhcp and DNS API together
libc: convert __dns.c to __dns.cc
dns: wire OSv DNS API and libc dns lookup code together.

build.mk | 1 +
core/dhcp.cc | 6 +++
core/dns.cc | 16 ++++++
include/dhcp.hh | 4 ++
include/dns.hh | 100 +++++++++++++++++++++++++++++++++++++
libc/network/{__dns.c => __dns.cc} | 60 ++++++++++++++++------
libc/network/{__dns.h => __dns.hh} | 8 +++
libc/network/__ipparse.c | 2 +-
libc/network/getaddrinfo.c | 2 +-
libc/network/getnameinfo.c | 2 +-
10 files changed, 183 insertions(+), 18 deletions(-)
create mode 100644 core/dns.cc
create mode 100644 include/dns.hh
rename libc/network/{__dns.c => __dns.cc} (79%)
rename libc/network/{__dns.h => __dns.hh} (85%)

--
1.8.1.2

[Benoît Canet]

This API will be used to glue the dhcp server with the libc dns lookup code.

Signed-off-by: Benoit Canet <ben...@irqsave.net>
---
build.mk | 1 +
core/dns.cc | 16 +++++++++
include/dns.hh | 100 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 117 insertions(+)

create mode 100644 core/dns.cc
create mode 100644 include/dns.hh

diff --git a/build.mk b/build.mk
index eaf5449..2010ecf 100644
--- a/build.mk
+++ b/build.mk
@@ -506,6 +506,7 @@ objects += core/percpu.o
objects += core/per-cpu-counter.o
objects += core/percpu-worker.o
objects += core/dhcp.o
+objects += core/dns.o

include $(src)/fs/build.mk
include $(src)/libc/build.mk
diff --git a/core/dns.cc b/core/dns.cc
new file mode 100644
index 0000000..cf98e49
--- /dev/null
+++ b/core/dns.cc
@@ -0,0 +1,16 @@
+/*
+ * Copyright (C) 2013 Nodalink, SARL.
+ *
+ * author: Benoît Canet <benoit...@irqsave.net>
+ *
+ * This work is open source software, licensed under the terms of the
+ * BSD license as described in the LICENSE file in the top-level directory.
+ */
+
+#include <dns.hh>
+
+namespace osv {
+
+dnsconfig* dnsconfig::_instance = nullptr;
+
+}
diff --git a/include/dns.hh b/include/dns.hh
new file mode 100644
index 0000000..ce57df5
--- /dev/null
+++ b/include/dns.hh
@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2013 Nodalink, SARL.
+ *
+ * author: Benoît Canet <benoit...@irqsave.net>
+ *
+ * This work is open source software, licensed under the terms of the
+ * BSD license as described in the LICENSE file in the top-level directory.
+ */
+
+#ifndef __OSV_CORE_DNS_HH__
+#define __OSV_CORE_DNS_HH__
+
+#include <algorithm>
+#include <iterator>
+#include <set>
+#include <string>
+#include <vector>
+
+#include <osv/mutex.h>
+
+#include <boost/asio/ip/address.hpp>
+
+#define dns_configuration (osv::dnsconfig::instance())
+
+namespace osv {
+
+template <class T> class config {
+public:
+ config() = default;
+
+ void clear() {
+ WITH_LOCK(_lock) {
+ _set.clear();
+ }
+ }
+
+ std::vector<T> get()
+ {
+ WITH_LOCK(_lock) {
+ std::vector<T> result(_set.begin(), _set.end());
+ return result;
+ }
+ }
+
+ void add(T x)
+ {
+ WITH_LOCK(_lock) {
+ _set.insert(x);
+ }
+ }
+
+ void remove(T x)
+ {
+ WITH_LOCK(_lock) {
+ _set.erase(x);
+ }
+ }
+
+ void update(std::vector<T> &remove, std::vector<T> &add)
+ {
+ WITH_LOCK(_lock) {
+ _erase(remove);
+ copy(add.begin(), add.end(), inserter(_set, _set.end()));
+ }
+ }
+
+private:
+ void _erase(std::vector<T> &vect)
+ {
+ // must be called under _lock
+ for(auto it = vect.begin(); it != vect.end(); ++it) {
+ _set.erase(*it);
+ }
+ }
+
+ mutex _lock;
+ std::set<T> _set;
+};
+
+class dnsconfig {
+public:
+ dnsconfig() = default;
+
+ static dnsconfig* instance() {
+ if (_instance == nullptr) {
+ _instance = new dnsconfig();
+ }
+ return (_instance);
+ }
+
+ config<boost::asio::ip::address> nameservers;
+ config<std::string> search_domains;
+
+private:
+ static dnsconfig* _instance;
+};
+
+}
+
+#endif //! __OSV_CORE_DNS_HH__
--
1.8.1.2

[Benoît Canet]

Signed-off-by: Benoit Canet <ben...@irqsave.net>
---

core/dhcp.cc | 6 ++++++
include/dhcp.hh | 4 ++++
2 files changed, 10 insertions(+)

diff --git a/core/dhcp.cc b/core/dhcp.cc
index 8800a17..06acf78 100644
--- a/core/dhcp.cc
+++ b/core/dhcp.cc
@@ -27,6 +27,7 @@

#include <debug.hh>
#include <dhcp.hh>
+#include <dns.hh>
#include <drivers/clock.hh>

using namespace boost::asio;
@@ -497,6 +498,11 @@ namespace dhcp {
"0.0.0.0",
dm.get_router_ip().to_string().c_str());

+ // Communicate DNS IPs to the DNS API
+ _old_dns_ips = _dns_ips;
+ _dns_ips = dm.get_dns_ips();
+ dns_configuration->nameservers.update(_old_dns_ips, _dns_ips);
+
// Send a DHCP Request
_state = DHCP_REQUEST;
dhcp_mbuf dm_req(false);
diff --git a/include/dhcp.hh b/include/dhcp.hh
index 827657f..4d74823 100644
--- a/include/dhcp.hh
+++ b/include/dhcp.hh
@@ -19,6 +19,7 @@
#include <osv/mutex.h>
#include <osv/debug.h>

+#include <boost/asio.hpp>
#include <boost/asio/ip/address.hpp>
#include <boost/asio/ip/address_v4.hpp>

@@ -222,6 +223,9 @@ namespace dhcp {
struct ifnet* _ifp;
dhcp_socket* _sock;

+ std::vector<boost::asio::ip::address> _dns_ips;
+ std::vector<boost::asio::ip::address> _old_dns_ips;
+
// Transaction id
u32 _xid;
};
--
1.8.1.2

[Benoît Canet]

This patch fixes issue #8 "Make Java InetAddress.getHostName() work".

Tests could be done with tst-dns-resolver.so.

Signed-off-by: Benoit Canet <ben...@irqsave.net>
---

libc/network/__dns.cc | 30 +++++++++++++++++++++++++++++-
1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/libc/network/__dns.cc b/libc/network/__dns.cc
index 8986077..9ca110e 100644
--- a/libc/network/__dns.cc
+++ b/libc/network/__dns.cc
@@ -14,6 +14,8 @@
#include "__dns.hh"
#include <stdio.h>

+#include <dns.hh>
+
#define TIMEOUT 5
#define RETRY 1000
#define PACKET_MAX 512
@@ -66,9 +68,35 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
clock_gettime(CLOCK_REALTIME, &ts);
id = (ts.tv_nsec + ts.tv_nsec/65536UL) & 0xffff;

+ /* Get nameservers from OSv first, fallback to resolv.conf */
+ auto dns_ips = dns_configuration->nameservers.get();
+ nns = 0;
+ for (auto it = dns_ips.begin(); nns < 3 && it != dns_ips.end(); ++it) {
+ auto ip = (*it);
+ if (ip.is_v4()) {
+ boost::asio::ip::address_v4::bytes_type bytes;
+ bytes = ip.to_v4().to_bytes();
+ memcpy(&ns[nns].sin.sin_addr.s_addr, &bytes,
+ sizeof(bytes));
+ ns[nns].sin.sin_family = family = AF_INET;
+ sl = sizeof sa.sin;
+ } else if (ip.is_v6()) {
+ boost::asio::ip::address_v6::bytes_type bytes;
+ bytes = ip.to_v6().to_bytes();
+ memcpy(&ns[nns].sin6.sin6_addr.s6_addr, &bytes,
+ sizeof(bytes));
+ ns[nns].sin6.sin6_family = family = AF_INET6;
+ sl = sizeof sa.sin6;
+ } else {
+ continue;
+ }
+ ns[nns].sin.sin_port = htons(53);
+ nns++;
+ }
+
/* Get nameservers from resolv.conf, fallback to localhost */
f = fopen("/etc/resolv.conf", "r");
- if (f) for (nns=0; nns<3 && fgets(line, sizeof line, f); ) {
+ if (f) for (;nns<3 && fgets(line, sizeof line, f); ) {
if (strncmp(line, "nameserver", 10) || !isspace(line[10]))
continue;
for (s=line+11; isspace(*s); s++);
--
1.8.1.2

[Benoît Canet]

Also convert it's header and change it's caller includes.

This patch is done so the libc resolver will be able to retrieve the dns from
OSv dns API.

Signed-off-by: Benoit Canet <ben...@irqsave.net>
---

libc/network/{__dns.c => __dns.cc} | 30 ++++++++++++++++--------------
libc/network/{__dns.h => __dns.hh} | 8 ++++++++

libc/network/__ipparse.c | 2 +-
libc/network/getaddrinfo.c | 2 +-
libc/network/getnameinfo.c | 2 +-

5 files changed, 27 insertions(+), 17 deletions(-)
rename libc/network/{__dns.c => __dns.cc} (90%)

rename libc/network/{__dns.h => __dns.hh} (85%)

diff --git a/libc/network/__dns.c b/libc/network/__dns.cc
similarity index 90%
rename from libc/network/__dns.c
rename to libc/network/__dns.cc
index 68ef63c..8986077 100644
--- a/libc/network/__dns.c
+++ b/libc/network/__dns.cc
@@ -11,7 +11,7 @@
#include <ctype.h>
#include <unistd.h>
#include <pthread.h>
-#include "__dns.h"
+#include "__dns.hh"
#include <stdio.h>

#define TIMEOUT 5
@@ -33,7 +33,7 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
union {
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
- } sa = {0}, ns[3] = {{0}};
+ } sa = {{0}}, ns[3] = {{{0}}};
socklen_t sl = 0;
int nns = 0;
int family = AF_UNSPEC;
@@ -64,7 +64,7 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)

/* Make a reasonably unpredictable id */
clock_gettime(CLOCK_REALTIME, &ts);
- id = ts.tv_nsec + ts.tv_nsec/65536UL & 0xffff;
+ id = (ts.tv_nsec + ts.tv_nsec/65536UL) & 0xffff;

/* Get nameservers from resolv.conf, fallback to localhost */
f = fopen("/etc/resolv.conf", "r");

@@ -95,7 +95,7 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
//pthread_cleanup_push(cleanup, (void *)(intptr_t)fd);
//pthread_setcancelstate(cs, 0);

- if (bind(fd, (void *)&sa, sl) < 0) {
+ if (bind(fd, (const sockaddr*)&sa, sl) < 0) {
errcode = EAI_SYSTEM;
goto out;
}
@@ -108,10 +108,11 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)

/* Query all configured namservers in parallel */
for (i=0; i<rrcnt; i++) if (rr[i]) for (j=0; j<nns; j++) {
- q[0] = id+i >> 8;
+ q[0] = (id+i) >> 8;
q[1] = id+i;
q[ql-3] = rr[i];
- sendto(fd, q, ql, MSG_NOSIGNAL, (void *)&ns[j], sl);
+ sendto(fd, q, ql, MSG_NOSIGNAL,
+ (const sockaddr*)&ns[j], sl);
}

/* Wait for a response, or until time to retry */
@@ -119,15 +120,16 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)

/* Process any and all replies */
while (got+failed < rrcnt && (rlen = recvfrom(fd, r, 512, 0,
- (void *)&sa, (socklen_t[1]){sl})) >= 2)
+ (sockaddr*)&sa, (socklen_t *)&sl)) >= 2)
{
/* Ignore replies from addresses we didn't send to */
for (i=0; i<nns; i++) if (!memcmp(ns+i, &sa, sl)) break;
if (i==nns) continue;

/* Compute index of the query from id */
- i = r[0]*256+r[1] - id & 0xffff;
- if ((unsigned)i >= rrcnt || !rr[i]) continue;
+ i = (r[0]*256+r[1] - id) & 0xffff;
+ if ((unsigned int)i >= (unsigned int) rrcnt || !rr[i])
+ continue;

/* Interpret the result code */
switch (r[3] & 15) {
@@ -181,8 +183,8 @@ int __dns_query(unsigned char *r, const void *a, int family, int ptr)
int rr[2], rrcnt = 1;

if (ptr) {
- if (family == AF_INET6) mkptr6(buf, a);
- else mkptr4(buf, a);
+ if (family == AF_INET6) mkptr6(buf, (unsigned char *) a);
+ else mkptr4(buf, (unsigned char *) a);
rr[0] = RR_PTR;
a = buf;
} else if (family == AF_INET6) {
@@ -192,7 +194,7 @@ int __dns_query(unsigned char *r, const void *a, int family, int ptr)
if (family != AF_INET) rr[rrcnt++] = RR_AAAA;
}

- return __dns_doqueries(r, a, rr, rrcnt);
+ return __dns_doqueries(r, (const char *)a, rr, rrcnt);
}


@@ -248,10 +250,10 @@ int __dns_get_rr(void *dest, size_t stride, size_t maxlen, size_t limit, const u
p += 1 + !!*p;
len = p[8]*256 + p[9];
if (p+len > r+512) return -1;
- if (p[1]==rr && len <= maxlen) {
+ if (p[1]==rr && (size_t)len <= maxlen) {
if (dec && decname(tmp, r, p+10)<0) return -1;
if (dest && limit) {
- if (dec) strcpy(dest, tmp);
+ if (dec) strcpy((char *)dest, tmp);
else memcpy(dest, p+10, len);
dest = (char *)dest + stride;
limit--;
diff --git a/libc/network/__dns.h b/libc/network/__dns.hh
similarity index 85%
rename from libc/network/__dns.h
rename to libc/network/__dns.hh
index 9a3f740..b9b3945 100644
--- a/libc/network/__dns.h
+++ b/libc/network/__dns.hh
@@ -5,6 +5,10 @@
#define RR_PTR 12
#define RR_AAAA 28

+#ifdef __cplusplus
+extern "C" {
+#endif
+
int __dns_count_addrs(const unsigned char *, int);
int __dns_get_rr(void *, size_t, size_t, size_t, const unsigned char *, int, int);

@@ -12,3 +16,7 @@ int __dns_query(unsigned char *, const void *, int, int);
int __ipparse(void *, int, const char *);

int __dns_doqueries(unsigned char *, const char *, int *, int);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/libc/network/__ipparse.c b/libc/network/__ipparse.c
index b0647aa..0e3c0a4 100644
--- a/libc/network/__ipparse.c
+++ b/libc/network/__ipparse.c
@@ -3,7 +3,7 @@
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
-#include "__dns.h"
+#include "__dns.hh"
#include <stdio.h>

int __ipparse(void *dest, int family, const char *s0)
diff --git a/libc/network/getaddrinfo.c b/libc/network/getaddrinfo.c
index 749b60f..b0d10e0 100644
--- a/libc/network/getaddrinfo.c
+++ b/libc/network/getaddrinfo.c
@@ -6,7 +6,7 @@
#include <unistd.h>
#include <string.h>
#include <ctype.h>
-#include "__dns.h"
+#include "__dns.hh"
#include <stdio.h>

static int is_valid(const char *host)
diff --git a/libc/network/getnameinfo.c b/libc/network/getnameinfo.c
index b756e6e..fc5acf6 100644
--- a/libc/network/getnameinfo.c
+++ b/libc/network/getnameinfo.c
@@ -8,7 +8,7 @@
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
-#include "__dns.h"
+#include "__dns.hh"

int getnameinfo(const struct sockaddr *restrict sa, socklen_t sl,
char *restrict node, socklen_t nodelen,
--
1.8.1.2

[Avi Kivity]

On 10/06/2013 02:01 PM, Benoît Canet wrote:
> This API will be used to glue the dhcp server with the libc dns lookup code.
>

This is too heavyweight IMO. A simple set_dns_config(vector<ip::address>
nameservers, vector<string> search_domains) is easier to use. Also, you
can put it straight in __dns.cc, no need for a third party. This way you
don't need a public read API, just write.

[Benoît Canet]

Le Sunday 06 Oct 2013 � 15:11:13 (+0300), Avi Kivity a �crit :

> On 10/06/2013 02:01 PM, Beno�t Canet wrote:
> >This API will be used to glue the dhcp server with the libc dns lookup code.
> >
> >@@ -0,0 +1,16 @@
> >+/*
> >+ * Copyright (C) 2013 Nodalink, SARL.
> >+ *

> >+ * author: Beno�t Canet <benoit...@irqsave.net>

> >+ *
> >+ * This work is open source software, licensed under the terms of the
> >+ * BSD license as described in the LICENSE file in the top-level directory.
> >+ */
> >+
> >+#include <dns.hh>
> >+
> >+namespace osv {
> >+
> >+dnsconfig* dnsconfig::_instance = nullptr;
> >+
> >+}
> >diff --git a/include/dns.hh b/include/dns.hh
> >new file mode 100644
> >index 0000000..ce57df5
> >--- /dev/null
> >+++ b/include/dns.hh
> >@@ -0,0 +1,100 @@
> >+/*
> >+ * Copyright (C) 2013 Nodalink, SARL.
> >+ *

> >+ * author: Beno�t Canet <benoit...@irqsave.net>

There is still the need to arbitrate between dhcpv4,dhcpv6 and the cli.

What do you think about it ?

Best regards

Beno�t

[Avi Kivity]

On 10/06/2013 03:19 PM, Beno�t Canet wrote:
> This is too heavyweight IMO. A simple
> set_dns_config(vector<ip::address> nameservers, vector<string>
> search_domains) is easier to use. Also, you can put it straight in
> __dns.cc, no need for a third party. This way you don't need a
> public read API, just write.
>
> There is still the need to arbitrate between dhcpv4,dhcpv6 and the cli.
>
> What do you think about it ?
>

Is it meaningful to have dhcpv4 and dhcpv6 (or SLAAC) at the same time
giving different results?

Note that

+ // Communicate DNS IPs to the DNS API
+ _old_dns_ips = _dns_ips;
+ _dns_ips = dm.get_dns_ips();
+ dns_configuration->nameservers.update(_old_dns_ips, _dns_ips);
+

fails if _dns_ips match something from a different source. So let's stick with single updater for now, when we have actual problems we can investigate the best API.

You are right about the CLI; so we need a reader API as well. But I think vector<> get_nameserver() is sufficient.

[Commit Bot]

From: Benoît Canet <ben...@irqsave.net>

libc: convert __dns.c to __dns.cc

Also convert it's header and change it's caller includes.

This patch is done so the libc resolver will be able to retrieve the dns
from
OSv dns API.

Signed-off-by: Benoit Canet <ben...@irqsave.net>

Signed-off-by: Avi Kivity <a...@cloudius-systems.com>

---
diff --git a/libc/network/__dns.cc b/libc/network/__dns.cc
--- a/libc/network/__dns.cc

limit--;diff --git a/libc/network/__dns.hh b/libc/network/__dns.hh
--- a/libc/network/__dns.hh

+++ b/libc/network/__dns.hh
@@ -5,6 +5,10 @@
#define RR_PTR 12
#define RR_AAAA 28

+#ifdef __cplusplus
+extern "C" {
+#endif
+
int __dns_count_addrs(const unsigned char *, int);
int __dns_get_rr(void *, size_t, size_t, size_t, const unsigned char *,
int, int);

@@ -12,3 +16,7 @@

int __ipparse(void *, int, const char *);

int __dns_doqueries(unsigned char *, const char *, int *, int);
+
+#ifdef __cplusplus
+}
+#endifdiff --git a/libc/network/__ipparse.c b/libc/network/__ipparse.c

--- a/libc/network/__ipparse.c
+++ b/libc/network/__ipparse.c
@@ -3,7 +3,7 @@
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
-#include "__dns.h"
+#include "__dns.hh"
#include <stdio.h>

int __ipparse(void *dest, int family, const char *s0)diff --git
a/libc/network/getaddrinfo.c b/libc/network/getaddrinfo.c

--- a/libc/network/getaddrinfo.c
+++ b/libc/network/getaddrinfo.c
@@ -6,7 +6,7 @@
#include <unistd.h>
#include <string.h>
#include <ctype.h>
-#include "__dns.h"
+#include "__dns.hh"
#include <stdio.h>

static int is_valid(const char *host)diff --git
a/libc/network/getnameinfo.c b/libc/network/getnameinfo.c