Replace nng_pipe_get_addr, nng_stream_get_addr, and the NNG_OPT_REMADDR option.

More direct access methods are provided instead.

This results in much lower friction when using, and is a step on the path
to removing NNG_OPT_LOCADDR as well.

We need to figure a solution for NNG_OPT_LOCADDR for dialers; for
listeners there is little use in it either, and it will be removed.
(Dialers will probably get a new NNG_OPT_BIND_IP option.)

5 files changed, 54 insertions, 26 deletions

diff --git a/docs/ref/api/pipe.md b/docs/ref/api/pipe.md
index 4fae1d06..97540908 100644
--- a/docs/ref/api/pipe.md
+++ b/docs/ref/api/pipe.md
@@ -84,6 +84,16 @@ either [`nng_dialer_id`] or [`nng_listener_id`] for the returned object will ret
 > The socket, or the endpoint, returned by these functions may be in the process of closing,
 > and might not be further usable as a result. (Other functions will result in [`NNG_ECLOSED`].)
 
+## Pipe Socket Addresses
+
+```c
+nng_err nng_pipe_peer_addr(nng_pipe p, nng_sockaddr *sap);
+nng_err nng_pipe_self_addr(nng_pipe p, nng_sockaddr *sap);
+```
+
+The [`nng_sockaddr`] for the local (self) or remote (peer) of the pipe is available using these
+functions. The associated address will be stored in the location pointed to by _sap_.
+
 ## Pipe Options
 
 ```c
@@ -91,7 +101,6 @@ nng_err nng_pipe_get_bool(nng_pipe p, const char *opt, bool *valp);
 nng_err nng_pipe_get_int(nng_pipe p, const char *opt, int *valp);
 nng_err nng_pipe_get_ms(nng_pipe p, const char *opt, nng_duration *valp);
 nng_err nng_pipe_get_size(nng_pipe p, const char *opt, size_t *valp);
-nng_err nng_pipe_get_addr(nng_pipe p, const char *opt, nng_sockaddr *valp);
 nng_err nng_pipe_get_string(nng_pipe p, const char *opt, const char **valp);
 nng_err nng_pipe_get_strcpy(nng_pipe p, const char *opt, char *val, size_t len);
 nng_err nng_pipe_get_strdup(nng_pipe p, const char *opt, char **valp);
@@ -102,7 +111,6 @@ nng_err nng_pipe_get_strlen(nng_pipe p, const char *opt, size_t *lenp);
 {{hi:`nng_pipe_get_int`}}
 {{hi:`nng_pipe_get_ms`}}
 {{hi:`nng_pipe_get_size`}}
-{{hi:`nng_pipe_get_addr`}}
 {{hi:`nng_pipe_get_string`}}
 {{hi:`nng_pipe_get_strcpy`}}
 {{hi:`nng_pipe_get_strdup`}}
diff --git a/docs/ref/api/stream.md b/docs/ref/api/stream.md
index a2f29238..3bed7923 100644
--- a/docs/ref/api/stream.md
+++ b/docs/ref/api/stream.md
@@ -103,7 +103,6 @@ nng_err nng_stream_get_string(nng_stream *s, const char *opt, const char **valp)
 {{hi:`nng_stream_get_int`}}
 {{hi:`nng_stream_get_ms`}}
 {{hi:`nng_stream_get_size`}}
-{{hi:`nng_stream_get_addr`}}
 {{hi:`nng_stream_get_string`}}
 These functions are used to obtain value of an option named _opt_ from the stream _s_, and store it in the location
 referenced by _valp_.
@@ -114,10 +113,6 @@ are available, and which type they may be accessed using.
 In the case of `nng_stream_get_string`, the string pointer is only guaranteed to be valid while the
 stream exists. Callers should make a copy of the data if required before closing the stream.
 
-> [!NOTE]:
-> The `nng_stream_get_addr` function is deprecated and will be removed. Use the
-> [`nng_stream_peer_addr`] or [`nng_stream_self_addr`] functions instead.
-
 ## Stream Factories
 
 ```c
diff --git a/docs/ref/migrate/nng1.md b/docs/ref/migrate/nng1.md
index 52b786cc..6e0a1143 100644
--- a/docs/ref/migrate/nng1.md
+++ b/docs/ref/migrate/nng1.md
@@ -173,6 +173,13 @@ address separated by a semicolon. This was provided for legacy libnanomsg
 compatibility, and is no longer offered. The correct way to specify a
 local address is by setting `NNG_OPT_LOCADDR` on the dialer.
 
+## Support for Remote Address Options Removed
+
+The `NNG_OPT_REMADDR` option is removed. For streams and pipes, there are
+[`nng_stream_peer_addr`] and [`nng_pipe_peer_addr`] functions. For dialers
+and stream dialers, the application should track the relevant information
+used to configure the listener.
+
 ## IPC Option Type Changes
 
 The types of [`NNG_OPT_PEER_GID`], [`NNG_OPT_PEER_PID`], [`NNG_OPT_PEER_UID`], and [`NNG_OPT_PEER_ZONEID`]
@@ -247,6 +254,9 @@ such as one ending in a suffix like `_bool` (to access a `bool` typed option).
 
 ## Stream Options
 
+The `nng_stream_get_addr` function is removed.
+Use the new [`nng_stream_peer_addr`] or [`nng_stream_peer_self_addr`] instead.
+
 The ability to set options on streams after they have been created is no longer present.
 (It turns out that this was not very useful.) All functions `nng_stream_set_xxx` are removed.
 For tuning the `NNG_OPT_TCP_NODELAY` or similar properties, set the option on the listener
@@ -277,6 +287,10 @@ before bringing them into the socket itself.
 The `NNG_OPT_TCP_BOUND_PORT` port is renamed to just [`NNG_OPT_BOUND_PORT`],
 and is available for listeners using transports based on either TCP or UDP.
 
+The `nng_pipe_get_addr` function has been removed, and replaced with the new
+[`nng_pipe_peer_addr`] and [`nng_pipe_self_addr`] functions. These should be
+easier to use.
+
 ## Socket Options
 
 The `NNG_OPT_PROTO`, `NNG_OPT_PROTONAME`, `NNG_OPT_PEER`, and `NNG_OPT_PEERNAME` options
@@ -401,4 +415,18 @@ The Layer 2 special ZeroTier transport has been removed.
 It is possible to use NNG with ZeroTier using TCP/IP, and a future update
 is planned to provided coexistence between ZeroTier & the native stack's TCP/IP using lwIP.
 
+## Abstract Autobinding No Longer Supported
+
+As we have removed `NNG_OPT_LOCADDR` for listeners, it is no longer possible to meaningfully
+use autobinding with abstract sockets on Linux. This is trivially worked around by using a
+large (say 128-bit) random integer as the name.
+
+This can be done via using of [`nng_random`] combined with `sprintf`, as the following example demonstrates:
+
+```c
+char url[256];
+snprintf(url, sizeof (url), `abstract://my-app-%08x-%08x-%08x-%08x",
+    nni_random(), nni_random(), nni_random(), nni_random());
+```
+
 {{#include ../xref.md}}
diff --git a/docs/ref/tran/ipc.md b/docs/ref/tran/ipc.md
index 3d046ee5..e5838d11 100644
--- a/docs/ref/tran/ipc.md
+++ b/docs/ref/tran/ipc.md
@@ -24,7 +24,7 @@ name in the file system where the socket or named pipe should be created.
 
 > [!NOTE]
 > When using relative paths on POSIX systems, the address used and returned
-> in properties like [`NNG_OPT_LOCADDR`] will also be relative.
+> in functions such as [`nng_pipe_peer_addr`] will also be relative.
 > Consequently, they will only be interpreted the same by processes that have
 > the same working directory.
 > To ensure maximum portability and safety, absolute paths are recommended
@@ -50,10 +50,11 @@ Abstract sockets use a URI-encoded name after the {{i:`abstract://`}} scheme, wh
 in the path, including embedded `NUL` bytes.
 For example, the name `"a\0b"` would be represented as `abstract://a%00b`.
 
-> [!TIP]
-> An empty name may be used with a listener to request "auto bind" be used to select a name.
-> In this case the system will allocate a free name.
-> The name assigned may be retrieved using [`NNG_OPT_LOCADDR`].
+> [!NOTE]
+> _NNG_ no longer supports "auto binding" where the kernel allocates a random unused name.
+> A simple solution to this is to allocate a large random number, such as a random UUID
+> or a concatenation of four random values from [`nng_random`]. The chance of a collision
+> can be made arbitrarily small by appending additional random values.
 
 Abstract names do not include the leading `NUL` byte used in the low-level socket address.
 
@@ -76,16 +77,14 @@ except for abstract sockets, which use [`nng_sockaddr_abstract`].
 The following transport options are supported by this transport,
 where supported by the underlying platform.
 
-| Option                    | Type             | Description                                                                                                        |
-| ------------------------- | ---------------- | ------------------------------------------------------------------------------------------------------------------ |
-| `NNG_OPT_IPC_PERMISSIONS` | `int`            | Settable on listeners before they start, this is the UNIX file mode used when creating the socket.                 |
-| `NNG_OPT_LOCADDR`         | [`nng_sockaddr`] | Local socket address, either [`nng_sockaddr_ipc`] or [`nng_sockaddr_abstract`].                                    |
-| `NNG_OPT_REMADDR`         | [`nng_sockaddr`] | Remote socket address, either [`nng_sockaddr_ipc`] or [`nng_sockaddr_abstract`].                                   |
-| `NNG_OPT_PEER_GID`        | `int`            | Read only option, returns the group ID of the process at the other end of the socket, if platform supports it.     |
-| `NNG_OPT_PEER_PID`        | `int`            | Read only option, returns the processed ID of the process at the other end of the socket, if platform supports it. |
-| `NNG_OPT_PEER_UID`        | `int`            | Read only option, returns the user ID of the process at the other end of the socket, if platform supports it.      |
-| `NNG_OPT_PEER_ZONEID`     | `int`            | Read only option, returns the zone ID of the process at the other end of the socket, if platform supports it.      |
-| [`NNG_OPT_LISTEN_FD`]     | `int`            | Write only for listeners before they start, use the named socket for accepting (for use with socket activation).   |
+| Option                    | Type  | Description                                                                                                        |
+| ------------------------- | ----- | ------------------------------------------------------------------------------------------------------------------ |
+| `NNG_OPT_IPC_PERMISSIONS` | `int` | Settable on listeners before they start, this is the UNIX file mode used when creating the socket.                 |
+| `NNG_OPT_PEER_GID`        | `int` | Read only option, returns the group ID of the process at the other end of the socket, if platform supports it.     |
+| `NNG_OPT_PEER_PID`        | `int` | Read only option, returns the processed ID of the process at the other end of the socket, if platform supports it. |
+| `NNG_OPT_PEER_UID`        | `int` | Read only option, returns the user ID of the process at the other end of the socket, if platform supports it.      |
+| `NNG_OPT_PEER_ZONEID`     | `int` | Read only option, returns the zone ID of the process at the other end of the socket, if platform supports it.      |
+| [`NNG_OPT_LISTEN_FD`]     | `int` | Write only for listeners before they start, use the named socket for accepting (for use with socket activation).   |
 
 ### Other Configuration Parameters
 
diff --git a/docs/ref/xref.md b/docs/ref/xref.md
index d64840cb..80a3d1b7 100644
--- a/docs/ref/xref.md
+++ b/docs/ref/xref.md
@@ -125,7 +125,6 @@
 [`nng_stream_get_int`]: ../api/stream.md#getting-stream-options
 [`nng_stream_get_ms`]: ../api/stream.md#getting-stream-options
 [`nng_stream_get_size`]: ../api/stream.md#getting-stream-options
-[`nng_stream_get_addr`]: ../api/stream.md#getting-stream-options
 [`nng_stream_get_string`]: ../api/stream.md#getting-stream-options
 [`nng_stream_dialer`]: ../api/stream.md#stream-factories
 [`nng_stream_listener`]: ../api/stream.md#stream-factories
@@ -162,7 +161,6 @@
 [`nng_stream_listener_get_int`]: ../api/stream.md#stream-factory-options
 [`nng_stream_listener_get_ms`]: ../api/stream.md#stream-factory-options
 [`nng_stream_listener_get_size`]: ../api/stream.md#stream-factory-options
-[`nng_stream_listener_get_addr`]: ../api/stream.md#stream-factory-options
 [`nng_stream_listener_get_string`]: ../api/stream.md#stream-factory-options
 [`nng_stream_listener_set_bool`]: ../api/stream.md#stream-factory-options
 [`nng_stream_listener_set_int`]: ../api/stream.md#stream-factory-options
@@ -257,9 +255,10 @@
 [`nng_pipe_get_int`]: ../api/pipe.md#pipe-options
 [`nng_pipe_get_ms`]: ../api/pipe.md#pipe-options
 [`nng_pipe_get_size`]: ../api/pipe.md#pipe-options
-[`nng_pipe_get_addr`]: ../api/pipe.md#pipe-options
 [`nng_pipe_get_string`]: ../api/pipe.md#pipe-options
 [`nng_pipe_notify`]: ../api/pipe.md#pipe-notifications
+[`nng_pipe_peer_addr`]: ../api/pipe.md#pipe-socket-addresses
+[`nng_pipe_self_addr`]: ../api/pipe.md#pipe-socket-addresses
 [`nng_sockaddr`]: ../TODO.md
 [`nng_sockaddr_in`]: ../TODO.md
 [`nng_sockaddr_in6`]: ../TODO.md
@@ -451,7 +450,6 @@
 [`NNG_OPT_RECVBUF`]: ../api/sock.md#NNG_OPT_RECVBUF
 [`NNG_OPT_RECVMAXSZ`]: ../api/sock.md#NNG_OPT_RECVMAXSZ
 [`NNG_OPT_LOCADDR`]: ../api/sock.md#NNG_OPT_LOCADDR
-[`NNG_OPT_REMADDR`]: ../api/sock.md#NNG_OPT_REMADDR
 [`NNG_OPT_PEER_UID`]: ../tran/ipc.md#NNG_OPT_PEER_UID
 [`NNG_OPT_PEER_GID`]: ../tran/ipc.md#NNG_OPT_PEER_GID
 [`NNG_OPT_PEER_PID`]: ../tran/ipc.md#NNG_OPT_PEER_PID