mdns ipv6 fixes; now works on ie11/safari, not linux:

* subscribe/announce on LL only
* add NSEC records if 4/6-only

copyparty/mdns.py

@@ -19,6 +19,7 @@ from .stolen.dnslib import (
     QTYPE,
     A,
     AAAA,
+    NSEC,
     SRV,
     PTR,
     TXT,
@@ -41,11 +42,12 @@ class MDNS_Sck(MC_Sck):
         self,
         sck: socket.socket,
         idx: int,
+        name: str,
         grp: str,
         ip: str,
         net: Union[IPv4Network, IPv6Network],
     ):
-        super(MDNS_Sck, self).__init__(sck, idx, grp, ip, net)
+        super(MDNS_Sck, self).__init__(sck, idx, name, grp, ip, net)
 
         self.bp_probe = b""
         self.bp_ip = b""
@@ -143,6 +145,16 @@ class MDNS(MCast):
             sreply = DNSRecord(DNSHeader(0, 0x8400))
             bye = DNSRecord(DNSHeader(0, 0x8400))
 
+            have4 = have6 = False
+            for s2 in self.srv.values():
+                if srv.idx != s2.idx:
+                    continue
+
+                if s2.v6:
+                    have6 = True
+                else:
+                    have4 = True
+
             for ip in srv.ips:
                 if ":" in ip:
                     qt = QTYPE.AAAA
@@ -162,6 +174,12 @@ class MDNS(MCast):
                 sreply.add_answer(r120)
                 bye.add_answer(r0)
 
+            if not have4 or not have6:
+                ns = NSEC(self.hn, ["AAAA" if have4 else "A"])
+                r = RR(self.hn, QTYPE.NSEC, DC.F_IN, 120, ns)
+                areply.add_ar(r)
+                sreply.add_ar(r)
+
             for sclass, props in self.svcs.items():
                 sname = props["name"]
                 sport = props["port"]
@@ -255,13 +273,13 @@ class MDNS(MCast):
             rx: list[socket.socket] = rdy[0]  # type: ignore
             self.rx4.cln()
             self.rx6.cln()
-            for srv in rx:
+            for sck in rx:
-                buf, addr = srv.recvfrom(4096)
+                buf, addr = sck.recvfrom(4096)
                 try:
-                    self.eat(buf, addr)
+                    self.eat(buf, addr, sck)
                 except:
-                    t = "{} \033[33m|{}| {}\n{}".format(
+                    t = "{} {} \033[33m|{}| {}\n{}".format(
-                        addr, len(buf), repr(buf)[2:-1], min_ex()
+                        self.srv[sck].name, addr, len(buf), repr(buf)[2:-1], min_ex()
                     )
                     self.log(t, 6)
 
@@ -279,9 +297,11 @@ class MDNS(MCast):
             for srv in self.srv.values():
                 srv.sck.sendto(srv.bp_bye, (srv.grp, 5353))
 
-    def eat(self, buf: bytes, addr: tuple[str, int]):
+        self.srv = {}
+
+    def eat(self, buf: bytes, addr: tuple[str, int], sck: socket.socket):
         cip = addr[0]
-        if cip.startswith("fe80") or cip.startswith("169.254"):
+        if cip.startswith("169.254"):
             return
 
         v6 = ":" in cip
@@ -290,14 +310,15 @@ class MDNS(MCast):
             return
 
         cache.add(buf)
-        srv: Optional[MDNS_Sck] = self.map_client(cip)  # type: ignore
+        srv: Optional[MDNS_Sck] = self.srv[sck] if v6 else self.map_client(cip)  # type: ignore
         if not srv:
             return
 
         now = time.time()
 
         if self.args.zmv:
-            self.log("[{}] \033[36m{} \033[0m|{}|".format(srv.ip, cip, len(buf)), "90")
+            t = "{} [{}] \033[36m{} \033[0m|{}|"
+            self.log(t.format(srv.name, srv.ip, cip, len(buf)), "90")
 
         p = DNSRecord.parse(buf)
         if self.args.zmvv:
@@ -336,8 +357,8 @@ class MDNS(MCast):
             else:
                 t += "Emergency stop; hostname '{}' got stolen"
 
-            t += "! Use --name to set another hostname.\n\nName taken by {}\n\nYour IPs: {}\n"
+            t += " on {}! Use --name to set another hostname.\n\nName taken by {}\n\nYour IPs: {}\n"
-            self.log(t.format(self.args.name, cips, list(self.sips)), 1)
+            self.log(t.format(self.args.name, srv.name, cips, list(self.sips)), 1)
             self.stop(True)
             return
 
@@ -348,11 +369,17 @@ class MDNS(MCast):
 
             # gvfs keeps repeating itself
             found = False
+            unicast = False
             for r in p.rr:
                 rname = U(r.rname).lower()
-                if rname == self.hn and r.ttl > 60:
+                if rname == self.hn:
-                    found = True
+                    if r.ttl > 60:
-                    break
+                        found = True
+                    if r.rclass == DC.F_IN:
+                        unicast = True
+
+            if unicast:
+                srv.sck.sendto(srv.bp_ip, (cip, 5353))
 
             if not found:
                 self.q[cip] = (0, srv, srv.bp_ip)

copyparty/multicast.py

@@ -26,12 +26,14 @@ class MC_Sck(object):
         self,
         sck: socket.socket,
         idx: int,
+        name: str,
         grp: str,
         ip: str,
         net: Union[IPv4Network, IPv6Network],
     ):
         self.sck = sck
         self.idx = idx
+        self.name = name
         self.grp = grp
         self.mreq = b""
         self.ip = ip
@@ -55,7 +57,7 @@ class MCast(object):
         self.port = port
 
         self.srv: dict[socket.socket, MC_Sck] = {}  # listening sockets
-        self.sips: set[str] = set()  # all listening ips
+        self.sips: set[str] = set()  # all listening ips (including failed attempts)
         self.b2srv: dict[bytes, MC_Sck] = {}  # binary-ip -> server socket
         self.b4: list[bytes] = []  # sorted list of binary-ips
         self.b6: list[bytes] = []  # sorted list of binary-ips
@@ -82,6 +84,7 @@ class MCast(object):
 
         ips = [x for x in ips if x not in ("::1", "127.0.0.1")]
 
+        # ip -> ip/prefix
         ips = [
             [x for x in self.hub.tcpsrv.netdevs if x.startswith(y + "/")][0]
             for y in ips
@@ -93,6 +96,10 @@ class MCast(object):
         if not self.grp6:
             ips = [x for x in ips if ":" not in x]
 
+        # discard non-linklocal ipv6
+        all_selected = ips[:]
+        ips = [x for x in ips if ":" not in x or x.startswith("fe80")]
+
         if not ips:
             raise Exception("no server IP matches the mdns config")
 
@@ -117,16 +124,39 @@ class MCast(object):
             except:
                 pass
 
+            # most ipv6 clients expect multicast on linklocal ip only;
+            # add a/aaaa records for the other nic IPs
+            other_ips: set[str] = set()
+            if v6 and netdev not in ("?", ""):
+                for oip, onic in self.hub.tcpsrv.netdevs.items():
+                    if (
+                        onic.split(",")[0] == netdev
+                        and oip in all_selected
+                        and ":" in oip
+                    ):
+                        other_ips.add(oip)
+
             net = ipaddress.ip_network(ip, False)
             ip = ip.split("/")[0]
-            srv = self.Srv(sck, idx, self.grp6 if ":" in ip else self.grp4, ip, net)
+            srv = self.Srv(
+                sck, idx, netdev, self.grp6 if ":" in ip else self.grp4, ip, net
+            )
+            for oth_ip in other_ips:
+                srv.ips[oth_ip.split("/")[0]] = ipaddress.ip_network(oth_ip, False)
+
+            # gvfs breaks if a linklocal ip appears in a dns reply
+            srv.ips = {k: v for k, v in srv.ips.items() if not k.startswith("fe80")}
+            if not srv.ips:
+                self.log("no routable IPs on {}; skipping [{}]".format(netdev, ip), 3)
+                continue
 
             try:
                 self.setup_socket(srv)
                 self.srv[sck] = srv
                 bound.append(ip)
             except:
-                self.log("announce failed on [{}]:\n{}".format(ip, min_ex()))
+                t = "announce failed on {} [{}]:\n{}"
+                self.log(t.format(netdev, ip, min_ex()), 3)
 
         if self.args.zm_msub:
             for s1 in self.srv.values():
@@ -145,18 +175,22 @@ class MCast(object):
                             if net1 == net2 and ip1 != ip2:
                                 s1.ips[ip2] = net2
 
-        self.sips = set([x.ip for x in self.srv.values()])
+        self.sips = set([x.split("/")[0] for x in all_selected])
+        for srv in self.srv.values():
+            assert srv.ip in self.sips
+
         return bound
 
     def setup_socket(self, srv: MC_Sck) -> None:
         sck = srv.sck
         if srv.v6:
             if self.args.zmv:
-                self.log("v6({}) idx({})".format(srv.ip, srv.idx), 6)
+                self.log("v6({}) idx({}) {}".format(srv.ip, srv.idx, srv.ips), 6)
 
-            bip = socket.inet_pton(socket.AF_INET6, srv.ip)
+            for ip in srv.ips:
-            self.b2srv[bip] = srv
+                bip = socket.inet_pton(socket.AF_INET6, ip)
-            self.b6.append(bip)
+                self.b2srv[bip] = srv
+                self.b6.append(bip)
 
             sck.bind((self.grp6 if srv.idx else "", self.port, 0, srv.idx))
             bgrp = socket.inet_pton(socket.AF_INET6, self.grp6)

copyparty/stolen/dnslib/dns.py

@@ -764,7 +764,7 @@ class NSEC(RD):
     label = property(get_label, set_label)
 
     def pack(self, buffer):
-        buffer.encode_name_nocompress(self.label)
+        buffer.encode_name(self.label)
         buffer.append(encode_type_bitmap(self.rrlist))
 
     def __repr__(self):

copyparty/tcpsrv.py

@@ -397,7 +397,7 @@ class TcpSrv(object):
             for nip in nic.ips:
                 ipa = nip.ip[0] if ":" in str(nip.ip) else nip.ip
                 sip = "{}/{}".format(ipa, nip.network_prefix)
-                if sip.startswith("fe80") or sip.startswith("169.254"):
+                if sip.startswith("169.254"):
                     # browsers dont impl linklocal
                     continue
 

docs/lics.txt

@@ -16,6 +16,10 @@ https://github.com/paulc/dnslib/
 C: 2010-2017 Paul Chakravarti
 L: BSD 2-Clause
 
+https://github.com/pydron/ifaddr/
+C: 2014 Stefan C. Mueller
+L: BSD-2-Clause
+
 https://github.com/giampaolo/pyftpdlib/
 C: 2007 Giampaolo Rodola
 L: MIT

scripts/sfx.ls

@@ -19,6 +19,7 @@ copyparty/httpconn.py,
 copyparty/httpsrv.py,
 copyparty/ico.py,
 copyparty/mdns.py,
+copyparty/multicast.py,
 copyparty/mtag.py,
 copyparty/res,
 copyparty/res/COPYING.txt,