p2p, bugfix: use NetPermissions::HasFlag() in CConnman::Bind()

PF_NOBAN is a multi-flag that includes PF_DOWNLOAD, so the conditional
in CConnman::Bind() using a bitwise AND will return the same result
for both the "noban" status and the "download" status.

Example:

`PF_DOWNLOAD` is `0b1000000`
`PF_NOBAN`    is `0b1010000`

This makes a check like `flags & PF_NOBAN` return `true` even if `flags`
is equal to `PF_DOWNLOAD`.

If `-whitebind=download@1.1.1.1:8765` is specified, then `1.1.1.1:8765`
should be added to the list of local addresses. We only want to avoid
adding to local addresses (that are advertised) a whitebind that has a
`noban@` flag.

As a result of a mis-check in `CConnman::Bind()` we would not have added
`1.1.1.1:8765` to the local addresses in the example above.

Co-authored-by: Vasil Dimov <vd@FreeBSD.org>

Github-Pull: bitcoin/bitcoin#21644
Rebased-From: dde69f20a01acca64ac21cb13993c6e4f8709f23

1 files changed, 3 insertions, 2 deletions

diff --git a/src/net.cpp b/src/net.cpp
index 15e52de94d..e0e806d959 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -2405,8 +2405,9 @@ NodeId CConnman::GetNewNodeId()
 
 
 bool CConnman::Bind(const CService &addr, unsigned int flags, NetPermissionFlags permissions) {
-    if (!(flags & BF_EXPLICIT) && !IsReachable(addr))
+    if (!(flags & BF_EXPLICIT) && !IsReachable(addr)) {
         return false;
+    }
     bilingual_str strError;
     if (!BindListenPort(addr, strError, permissions)) {
         if ((flags & BF_REPORT_ERROR) && clientInterface) {
@@ -2415,7 +2416,7 @@ bool CConnman::Bind(const CService &addr, unsigned int flags, NetPermissionFlags
         return false;
     }
 
-    if (addr.IsRoutable() && fDiscover && !(flags & BF_DONT_ADVERTISE) && !(permissions & PF_NOBAN)) {
+    if (addr.IsRoutable() && fDiscover && !(flags & BF_DONT_ADVERTISE) && !NetPermissions::HasFlag(permissions, NetPermissionFlags::PF_NOBAN)) {
         AddLocal(addr, LOCAL_BIND);
     }