Merge lp:~ptman/hipl/reload into lp:hipl

[Paul Tötterman]

Implement sane SIGHUP handling (reload configs)

Fixes #1132042 and #1189371

[Miika Komu (miika-iki)]

Tested, works. There's still some IOerror left (I'll report this separately), but I think you could fix it directly in the trunk.

review: Approve

[lp:~ptman/hipl/reload]

6425. By Paul Tötterman on 2013-08-11

Retry in case of EINTR

6426. By Paul Tötterman on 2013-08-11

Merge trunk

6427. By Paul Tötterman on 2013-08-12

Merged trunk

=== modified file 'debian/hipl-dnsproxy.install.in'
--- debian/hipl-dnsproxy.install.in	2011-02-08 17:55:52 +0000
+++ debian/hipl-dnsproxy.install.in	2013-08-12 13:20:15 +0000
@@ -3,3 +3,4 @@
 debian/tmp/@pythondir@/DNS @pythondir@
 debian/tmp/@pythondir@/hipdnskeyparse @pythondir@
 debian/tmp/@pythondir@/hipdnsproxy @pythondir@
+debian/resolvconf/hipdnsproxy etc/resolvconf/update.d
 
=== added directory 'debian/resolvconf'
=== added file 'debian/resolvconf/hipdnsproxy'
--- debian/resolvconf/hipdnsproxy	1970-01-01 00:00:00 +0000
+++ debian/resolvconf/hipdnsproxy	2013-08-12 13:20:15 +0000
@@ -0,0 +1,2 @@
+#!/bin/sh
+/bin/kill -HUP `/usr/bin/head -1 /var/run/hipdnsproxy.pid` > /dev/null 2>&1
 
=== modified file 'tools/hipdnsproxy/DNS/Type.py'
--- tools/hipdnsproxy/DNS/Type.py	2010-02-18 16:45:11 +0000
+++ tools/hipdnsproxy/DNS/Type.py	2013-08-12 13:20:15 +0000
@@ -28,6 +28,7 @@
 TXT = 16        # text strings
 AAAA = 28       # IPv6 AAAA records (RFC 1886)
 SRV = 33        # DNS RR for specifying the location of services (RFC 2782)
+HIP = 55        # Host Identity Protocol (RFC 5205)
 
 
 # Additional TYPE values from host.c source
 
=== modified file 'tools/hipdnsproxy/dnsproxy.py'
--- tools/hipdnsproxy/dnsproxy.py	2013-05-26 15:29:43 +0000
+++ tools/hipdnsproxy/dnsproxy.py	2013-08-12 13:20:15 +0000
@@ -82,7 +82,7 @@
 import hosts
 import resolvconf
 import util
-from DNS import Serialize, DeSerialize
+from DNS import Serialize, DeSerialize, Type
 
 
 DEFAULT_HOSTS = '/etc/hosts'
@@ -167,7 +167,6 @@
         self.server_port = server_port
 
         self.resolvconf = resolvconf.ResolvConf()
-        self.resolvconf.parse()
 
         if self.hostsnames is None:
             self.hostsnames = []
@@ -218,8 +217,6 @@
         env = os.environ
         if self.server_ip is None:
             self.server_ip = env.get('SERVER', None)
-        if self.server_ip is None:
-            self.server_ip = self.resolvconf.nameserver
         if self.server_port is None:
             server_port = env.get('SERVERPORT', None)
             if server_port is not None:
@@ -367,7 +364,7 @@
 
         # convert 1.2....1.0.0.1.0.0.2.ip6.arpa to a HIT and
         # map host name to address from cache
-        if qtype == 12:
+        if qtype == Type.PTR:
             lr_ptr = None
             addr_str = hosts.ptr_to_addr(qname)
             if (not self.disable_lsi and addr_str is not None and
@@ -387,19 +384,19 @@
                 add_hit_ip_map(lr_aaaa_hit[0], lr_a[0])
             if lr_aaaa is not None:
                 add_hit_ip_map(lr_aaaa_hit[0], lr_aaaa[0])
-            if qtype == 28:               # 28: AAAA
+            if qtype == Type.AAAA:
                 result = lr_aaaa_hit
-            elif qtype == 1 and not self.disable_lsi:  # 1: A
+            elif qtype == Type.A and not self.disable_lsi:
                 lsi = hit_to_lsi(lr_aaaa_hit[0])
                 if lsi is not None:
                     result = (lsi, lr_aaaa_hit[1])
         elif self.prefix and packet['questions'][0][0].startswith(self.prefix):
             result = None
-        elif qtype == 28:
+        elif qtype == Type.AAAA:
             result = lr_aaaa
-        elif qtype == 1:
+        elif qtype == Type.A:
             result = lr_a
-        elif qtype == 12 and lr_ptr is not None:  # 12: PTR
+        elif qtype == Type.PTR and lr_ptr is not None:
             result = (lr_ptr, self.hosts_ttl)
 
         if result is not None:
@@ -418,7 +415,7 @@
 
         dns_hit_found = False
         for answer in packet['answers']:
-            if answer[1] == 55:
+            if answer[1] == Type.HIP:
                 dns_hit_found = True
                 break
 
@@ -429,20 +426,20 @@
             lsi_ans = []
 
             for answer in packet['answers']:
-                if answer[1] != 55:
+                if answer[1] != Type.HIP:
                     continue
 
                 hit = socket.inet_ntop(socket.AF_INET6, answer[7])
-                hit_ans.append([qname, 28, 1, answer[3], hit])
+                hit_ans.append([qname, Type.AAAA, 1, answer[3], hit])
 
-                if qtype == 1 and not self.disable_lsi:
+                if qtype == Type.A and not self.disable_lsi:
                     lsi = hit_to_lsi(hit)
                     if lsi is not None:
                         lsi_ans.append([qname, 1, 1, self.hosts_ttl, lsi])
 
                 self.cache_name(qname, hit, answer[3])
 
-        if qtype == 28 and hit_found:
+        if qtype == Type.AAAA and hit_found:
             packet['answers'] = hit_ans
         elif lsi is not None:
             packet['answers'] = lsi_ans
@@ -459,10 +456,6 @@
 
         self.parameter_defaults()
 
-        if self.server_ip is None:
-            logging.critical('No upstream DNS server, exiting...')
-            return
-
         # Default virtual interface and address for dnsproxy to
         # avoid problems with other dns forwarders (e.g. dnsmasq)
         os.system('ifconfig lo:53 %s' % (self.bind_ip,))
@@ -475,7 +468,6 @@
                           self.bind_port)
             return
 
-        self.resolvconf.nameserver = self.bind_ip
 
         servsock.settimeout(self.app_timeout)
 
@@ -494,10 +486,20 @@
 
         query_id = 1
 
-        util.init_wantdown()
-        util.init_wantdown_int()  # Keyboard interrupts
+        util.init_wantdown()  # Initialize signal handler for shutdown
+        util.init_hup()  # Initialize signal handler for reload
 
         while not util.wantdown():
+            self.resolvconf.parse()
+
+            if self.server_ip is None:
+                self.server_ip = self.resolvconf.nameserver
+
+            if util.wanthup():
+                logging.info('Received SIGHUP. Picking %s as new upstream '
+                             'DNS server', self.server_ip)
+                util.wanthup(False)
+
             logging.info('Connecting to upstream DNS server...')
             if ':' not in self.server_ip:
                 server_family = socket.AF_INET
@@ -509,12 +511,13 @@
                 clisock.connect((self.server_ip, self.server_port))
                 connected = True
                 logging.debug('... connected!')
+                self.resolvconf.nameserver = self.bind_ip
             except socket.error:
                 logging.error('Connecting to upstream DNS server failed!')
                 time.sleep(3)
                 connected = False
 
-            while connected and (not util.wantdown()):
+            while connected and (not util.wantdown()) and (not util.wanthup()):
                 try:
                     self.hosts_recheck()
 
@@ -532,7 +535,7 @@
 
                         sent_answer = False
 
-                        if qtype in (1, 28, 12):
+                        if qtype in (Type.A, Type.AAAA, Type.PTR):
                             if self.hip_cache_lookup(packet):
                                 try:
                                     outbuf = Serialize(packet).get_packet()
@@ -563,21 +566,22 @@
                             query_id = (query_id % 65535) + 1
                             pckt = copy.copy(packet)
                             pckt['id'] = query_id
-                            if ((qtype == 28 or
-                                 (qtype == 1 and not self.disable_lsi)) and not
-                                is_reverse_hit_query(
+                            if ((qtype == Type.AAAA or
+                                 (qtype == Type.A and
+                                  not self.disable_lsi)) and
+                                not is_reverse_hit_query(
                                     packet['questions'][0][0])):
 
                                 if not self.prefix:
-                                    pckt['questions'][0][1] = 55
+                                    pckt['questions'][0][1] = Type.HIP
                                 if (self.prefix and
                                     pckt['questions'][0][0].startswith(
                                         self.prefix)):
                                     pckt['questions'][0][0] = pckt[
                                         'questions'][0][0][len(self.prefix):]
-                                    pckt['questions'][0][1] = 55
+                                    pckt['questions'][0][1] = Type.HIP
 
-                            if qtype == 12 and not self.disable_lsi:
+                            if qtype == Type.PTR and not self.disable_lsi:
                                 qname = packet['questions'][0][0]
                                 addr_str = hosts.ptr_to_addr(qname)
                                 if (addr_str is not None and
@@ -616,7 +620,8 @@
                             # Replace with the original query id
                             packet['id'] = packet_o['id']
 
-                            if qtype == 55 and query_o[3] in (1, 28):
+                            if qtype == Type.HIP and query_o[3] in (Type.A,
+                                                                    Type.AAAA):
                                 # Restore qtype
                                 packet['questions'][0][1] = query_o[3]
                                 self.hip_lookup(packet)
@@ -634,18 +639,18 @@
                                     for answer in packet['answers']:
                                         answer[0] = self.prefix + answer[0]
 
-                            elif qtype in (1, 28):
+                            elif qtype in (Type.A, Type.AAAA):
                                 hit = self.getaaaa_hit(qname)
                                 ip6 = self.getaaaa(qname)
                                 ip4 = self.geta(qname)
                                 for answer in packet['answers']:
-                                    if answer[1] in (1, 28):
+                                    if answer[1] in (Type.A, Type.AAAA):
                                         self.cache_name(qname, answer[4],
                                                         answer[3])
                                 if hit is not None:
                                     for answer in packet['answers']:
-                                        if (answer[1] == 1 or
-                                            (answer[1] == 28 and not
+                                        if (answer[1] == Type.A or
+                                            (answer[1] == Type.AAAA and not
                                              hosts.valid_hit(answer[4]))):
                                             add_hit_ip_map(hit[0], answer[4])
                                     # Reply with HIT/LSI once it's been mapped
@@ -675,14 +680,15 @@
                                     # IP was queried for cache only
                                     send_reply = False
 
-                            elif qtype == 12 and isinstance(query_o[3], str):
+                            elif qtype == Type.PTR and isinstance(query_o[3],
+                                                                  str):
                                 packet['questions'][0][0] = query_o[3]
                                 for answer in packet['answers']:
                                     answer[0] = query_o[3]
 
                             if query_again:
                                 if hit_found:
-                                    qtypes = [28, 1]
+                                    qtypes = [Type.AAAA, Type.A]
                                     pckt = copy.deepcopy(packet)
                                 else:
                                     qtypes = [query_o[3]]
 
=== modified file 'tools/hipdnsproxy/resolvconf.py'
--- tools/hipdnsproxy/resolvconf.py	2013-05-26 15:28:42 +0000
+++ tools/hipdnsproxy/resolvconf.py	2013-08-12 13:20:15 +0000
@@ -26,6 +26,7 @@
 """Handler for resolv.conf, including resolvconf(8)."""
 
 import collections
+import errno
 import logging
 import os
 import subprocess
@@ -112,16 +113,25 @@
 
     @classmethod
     def fragments(cls):
-        proc = subprocess.Popen([ResolvConf.LIST_RECORDS],
-                cwd=ResolvConf.FRAGMENT_DIR, stdout=subprocess.PIPE)
-
-        out = proc.stdout.readlines()
-        proc.communicate()
-        proc.wait()
-
-        frags = [x.strip() for x in out]
-
-        return [os.path.join(ResolvConf.FRAGMENT_DIR, x) for x in frags]
+        """Return list of resolvconf fragments."""
+        retries = 3
+        while retries > 0:
+            try:
+                proc = subprocess.Popen([ResolvConf.LIST_RECORDS],
+                        cwd=ResolvConf.FRAGMENT_DIR, stdout=subprocess.PIPE)
+
+                out = proc.stdout.readlines()
+                proc.communicate()
+                proc.wait()
+
+                frags = [x.strip() for x in out]
+
+                return [os.path.join(ResolvConf.FRAGMENT_DIR, x) for x in frags]
+            except IOError, ioe:
+                if ioe.errno != errno.EINTR:
+                    raise
+                retries -= 1
+
 
     @classmethod
     def resolvconf_add(cls, ifile):
 
=== modified file 'tools/hipdnsproxy/util.py'
--- tools/hipdnsproxy/util.py	2013-02-22 15:16:12 +0000
+++ tools/hipdnsproxy/util.py	2013-08-12 13:20:15 +0000
@@ -32,8 +32,7 @@
 import struct
 import sys
 
-__FLAGS = {'down': False,
-           'alarm': False}
+__FLAGS = {'down': False, 'hup': False}
 
 
 class Random:
@@ -67,42 +66,35 @@
 
 def sighandler(signum, unused_frame):
     """A signal handler that toggles flags about received signals."""
-    if signum == signal.SIGTERM:
-        __FLAGS['down'] = True
-    if signum == signal.SIGINT:
-        __FLAGS['down'] = True
-    if signum == signal.SIGALRM:
-        __FLAGS['alarm'] = True
+    if signum in (signal.SIGTERM, signal.SIGINT):
+        __FLAGS['down'] = True
+    if signum == signal.SIGHUP:
+        __FLAGS['hup'] = True
 
 
 def init_wantdown():
     """Hook signal handler to SIGTERM."""
     signal.signal(signal.SIGTERM, sighandler)
-
-
-def init_wantdown_int():
-    """Hook signal handler to SIGINT."""
     signal.signal(signal.SIGINT, sighandler)
 
 
-def init_wantalarm():
-    """Hook signal handler to SIGALRM."""
-    signal.signal(signal.SIGALRM, sighandler)
+def init_hup():
+    """Hook signal handler to SIGHUP."""
+    signal.signal(signal.SIGHUP, sighandler)
 
 
 def wantdown():
     """Check if SIGINT or SIGTERM has been received."""
-    previous = __FLAGS['down']
-    __FLAGS['down'] = False
-    return previous
-
-
-def wantalarm():
-    """Check if SIGALRM has been received."""
-    previous = __FLAGS['alarm']
-    __FLAGS['alarm'] = False
-    return previous
-
+    return __FLAGS['down']
+
+def wanthup(reset=None):
+    """Check if SIGHUP has been received."""
+    previous = __FLAGS['hup']
+
+    if reset is not None:
+        __FLAGS['hup'] = reset
+
+    return previous
 
 TMULT = (
     (re.compile('^(?P<tval>-?\d+(\.\d*))(s|)$', re.I), float, 1),