Merge #19628: net: change CNetAddr::ip to have flexible size

102867c587f5f7954232fb8ed8e85cda78bb4d32 net: change CNetAddr::ip to have flexible size (Vasil Dimov)
1ea57ad67406b3aaaef5254bc2fa7e4134f3a6df net: don't accept non-left-contiguous netmasks (Vasil Dimov)

Pull request description:

  (chopped off from #19031 to ease review)

  Before this change `CNetAddr::ip` was a fixed-size array of 16 bytes,
  not being able to store larger addresses (e.g. TORv3) and encoded
  smaller ones as 16-byte IPv6 addresses.

  Change its type to `prevector`, so that it can hold larger addresses and
  do not disguise non-IPv6 addresses as IPv6. So the IPv4 address
  `1.2.3.4` is now encoded as `01020304` instead of
  `00000000000000000000FFFF01020304`.

  Rename `CNetAddr::ip` to `CNetAddr::m_addr` because it is not an "IP" or
  "IP address" (TOR addresses are not IP addresses).

  In order to preserve backward compatibility with serialization (where
  e.g. `1.2.3.4` is serialized as `00000000000000000000FFFF01020304`)
  introduce `CNetAddr` dedicated legacy serialize/unserialize methods.

  Adjust `CSubNet` accordingly. Still use `CSubNet::netmask[]` of fixed 16
  bytes, but use the first 4 for IPv4 (not the last 4). Do not accept
  invalid netmasks that have 0-bits followed by 1-bits and only allow
  subnetting for IPv4 and IPv6.

  Co-authored-by: Carl Dong <contact@carldong.me>

ACKs for top commit:
  sipa:
    utACK 102867c587f5f7954232fb8ed8e85cda78bb4d32
  MarcoFalke:
    Concept ACK 102867c587f5f7954232fb8ed8e85cda78bb4d32
  ryanofsky:
    Code review ACK 102867c587f5f7954232fb8ed8e85cda78bb4d32. Just many suggested updates since last review. Thanks for following up on everything!
  jonatack:
    re-ACK 102867c587f5f7954232fb8ed8e85cda78bb4d32 diff review, code review, build/tests/running bitcoind with ipv4/ipv6/onion peers
  kallewoof:
    ACK 102867c587f5f7954232fb8ed8e85cda78bb4d32

Tree-SHA512: d60bf716cecf8d3e8146d2f90f897ebe956befb16f711a24cfe680024c5afc758fb9e4a0a22066b42f7630d52cf916318bedbcbc069ae07092d5250a11e8f762

1 files changed, 13 insertions, 4 deletions

diff --git a/src/test/netbase_tests.cpp b/src/test/netbase_tests.cpp
index 49073ea657..6681c92bb5 100644
--- a/src/test/netbase_tests.cpp
+++ b/src/test/netbase_tests.cpp
@@ -185,6 +185,7 @@ BOOST_AUTO_TEST_CASE(subnet_test)
     BOOST_CHECK(!ResolveSubNet("1.2.3.0/-1").IsValid());
     BOOST_CHECK(ResolveSubNet("1.2.3.0/32").IsValid());
     BOOST_CHECK(!ResolveSubNet("1.2.3.0/33").IsValid());
+    BOOST_CHECK(!ResolveSubNet("1.2.3.0/300").IsValid());
     BOOST_CHECK(ResolveSubNet("1:2:3:4:5:6:7:8/0").IsValid());
     BOOST_CHECK(ResolveSubNet("1:2:3:4:5:6:7:8/33").IsValid());
     BOOST_CHECK(!ResolveSubNet("1:2:3:4:5:6:7:8/-1").IsValid());
@@ -216,6 +217,11 @@ BOOST_AUTO_TEST_CASE(subnet_test)
     BOOST_CHECK(CSubNet(ResolveIP("1:2:3:4:5:6:7:8")).Match(ResolveIP("1:2:3:4:5:6:7:8")));
     BOOST_CHECK(!CSubNet(ResolveIP("1:2:3:4:5:6:7:8")).Match(ResolveIP("1:2:3:4:5:6:7:9")));
     BOOST_CHECK(CSubNet(ResolveIP("1:2:3:4:5:6:7:8")).ToString() == "1:2:3:4:5:6:7:8/128");
+    // IPv4 address with IPv6 netmask or the other way around.
+    BOOST_CHECK(!CSubNet(ResolveIP("1.1.1.1"), ResolveIP("ffff::")).IsValid());
+    BOOST_CHECK(!CSubNet(ResolveIP("::1"), ResolveIP("255.0.0.0")).IsValid());
+    // Can't subnet TOR (or any other non-IPv4 and non-IPv6 network).
+    BOOST_CHECK(!CSubNet(ResolveIP("5wyqrzbvrdsumnok.onion"), ResolveIP("255.0.0.0")).IsValid());
 
     subnet = ResolveSubNet("1.2.3.4/255.255.255.255");
     BOOST_CHECK_EQUAL(subnet.ToString(), "1.2.3.4/32");
@@ -290,11 +296,13 @@ BOOST_AUTO_TEST_CASE(subnet_test)
     BOOST_CHECK_EQUAL(subnet.ToString(), "1::/16");
     subnet = ResolveSubNet("1:2:3:4:5:6:7:8/0000:0000:0000:0000:0000:0000:0000:0000");
     BOOST_CHECK_EQUAL(subnet.ToString(), "::/0");
+    // Invalid netmasks (with 1-bits after 0-bits)
     subnet = ResolveSubNet("1.2.3.4/255.255.232.0");
-    BOOST_CHECK_EQUAL(subnet.ToString(), "1.2.0.0/255.255.232.0");
+    BOOST_CHECK(!subnet.IsValid());
+    subnet = ResolveSubNet("1.2.3.4/255.0.255.255");
+    BOOST_CHECK(!subnet.IsValid());
     subnet = ResolveSubNet("1:2:3:4:5:6:7:8/ffff:ffff:ffff:fffe:ffff:ffff:ffff:ff0f");
-    BOOST_CHECK_EQUAL(subnet.ToString(), "1:2:3:4:5:6:7:8/ffff:ffff:ffff:fffe:ffff:ffff:ffff:ff0f");
-
+    BOOST_CHECK(!subnet.IsValid());
 }
 
 BOOST_AUTO_TEST_CASE(netbase_getgroup)
@@ -428,7 +436,8 @@ BOOST_AUTO_TEST_CASE(netbase_dont_resolve_strings_with_embedded_nul_characters)
     BOOST_CHECK(!LookupSubNet(std::string("1.2.3.0/24\0", 11), ret));
     BOOST_CHECK(!LookupSubNet(std::string("1.2.3.0/24\0example.com", 22), ret));
     BOOST_CHECK(!LookupSubNet(std::string("1.2.3.0/24\0example.com\0", 23), ret));
-    BOOST_CHECK(LookupSubNet(std::string("5wyqrzbvrdsumnok.onion", 22), ret));
+    // We only do subnetting for IPv4 and IPv6
+    BOOST_CHECK(!LookupSubNet(std::string("5wyqrzbvrdsumnok.onion", 22), ret));
     BOOST_CHECK(!LookupSubNet(std::string("5wyqrzbvrdsumnok.onion\0", 23), ret));
     BOOST_CHECK(!LookupSubNet(std::string("5wyqrzbvrdsumnok.onion\0example.com", 34), ret));
     BOOST_CHECK(!LookupSubNet(std::string("5wyqrzbvrdsumnok.onion\0example.com\0", 35), ret));