fixes #287 remove NNG_OPT_DOMAIN, NNG_OPT_PROTOCOL, and NNG_OPT_TRANSPORT

While here we documented that certain options are not supported in the
compatibility layer.

5 files changed, 71 insertions, 31 deletions

diff --git a/docs/man/nng_compat.3compat.adoc b/docs/man/nng_compat.3compat.adoc
index cc6271f4..a0ac64c2 100644
--- a/docs/man/nng_compat.3compat.adoc
+++ b/docs/man/nng_compat.3compat.adoc
@@ -79,6 +79,51 @@ supplied here later.
 In the meantime it can be found online at the
 http://nanomsg.org[nanomsg site].
 
+There are a few caveats, that should be kept in mind.
+
+NOTE: Socket numbers can be quite large.
+The legacy _libnanomsg_ attempted to reuse socket numbers, like
+file descriptors in UNIX systems.
+The _nng_ library avoids this to prevent accidental reuse or
+collision after a descriptor is closed.
+Consequently, socket numbers can become quite large, and should
+probably not be used for array indices.
+
+NOTE: The following options (`nn_getsockopt`) are unsupported:
+`NN_PROTOCOL`, `NN_SNDPRIO`, `NN_RCVPRIO`, `NN_IPV4ONLY`.
+Some of these will probably be added back in the future when
+the relevant support is added to _nng_.
+
+NOTE: Statistics (`nn_get_statistic`) are unsupported.
+The plan is to support statistics in the native _nng_ API, but
+we think there is no need for this in a compatibility layer.
+Hence, this function returns `ENOTSUP`.
+
+NOTE: Some transports can support longer URLs than legacy _libnanomsg_ can.
+It is a good idea to use short pathnames in URLs if interoperability
+is a concern.
+
+NOTE: Some transports are unusable from this mode.
+In particular, this legacy API offers no way to configure
+TLS parameters that are required for use.
+
+NOTE: ABI versioning is not supported.
+We don't offer the `NN_VERSION_` macros.  Sorry.
+
+NOTE: Runtime symbol information is not implemented.
+Specifically, there is no `nn_symbol()` function yet.
+(This may be addressed later if there is a need.)
+
+IMPORTANT: The `nn_term()` function is destructive and should be avoided.
+This function closes down all sockets, and really there is no good
+reason to ever use it.
+Removal from existing code is advised.
+(Keep track of sockets and close them explicitly if necessary.)
+
+IMPORTANT: It *is* possible at present to intermix sockets between the new and
+the old APIs, but this is not a guaranteed feature, and should only
+be used temporarily to facilitate transitioning code to the new APIs.
+
 // === Common Functions
 //
 // The following common functions exist in _libnng_.
diff --git a/src/compat/nanomsg/nn.c b/src/compat/nanomsg/nn.c
index 1d5bcfbb..01b51503 100644
--- a/src/compat/nanomsg/nn.c
+++ b/src/compat/nanomsg/nn.c
@@ -613,7 +613,6 @@ static const struct {
 	{ NN_SOL_SOCKET, NN_MAXTTL, NNG_OPT_MAXTTL },
 	{ NN_SOL_SOCKET, NN_RCVTIMEO, NNG_OPT_RECVTIMEO },
 	{ NN_SOL_SOCKET, NN_SNDTIMEO, NNG_OPT_SENDTIMEO },
-	{ NN_SOL_SOCKET, NN_DOMAIN, NNG_OPT_DOMAIN },
 	{ NN_SOL_SOCKET, NN_SOCKET_NAME, NNG_OPT_SOCKNAME },
 	{ NN_REQ, NN_REQ_RESEND_IVL, NNG_OPT_REQ_RESENDTIME },
 	{ NN_SUB, NN_SUB_SUBSCRIBE, NNG_OPT_SUB_SUBSCRIBE },
@@ -622,6 +621,22 @@ static const struct {
 	// XXX: IPV4ONLY, SNDPRIO, RCVPRIO
 };
 
+static int
+nn_getdomain(int s, void *valp, size_t *szp)
+{
+	int i;
+	int rv;
+
+	if ((rv = nng_getopt_int((nng_socket) s, NNG_OPT_RAW, &i)) != 0) {
+		nn_seterror(rv);
+		return (-1);
+	}
+	i = i ? AF_SP_RAW : AF_SP;
+	memcpy(valp, &i, *szp < sizeof(int) ? *szp : sizeof(int));
+	*szp = sizeof(int);
+	return (0);
+}
+
 int
 nn_getsockopt(int s, int nnlevel, int nnopt, void *valp, size_t *szp)
 {
@@ -637,6 +652,10 @@ nn_getsockopt(int s, int nnlevel, int nnopt, void *valp, size_t *szp)
 	}
 
 	if (name == NULL) {
+		if (nnlevel == NN_SOL_SOCKET && nnopt == NN_DOMAIN) {
+			return (nn_getdomain(s, valp, szp));
+		}
+
 		errno = ENOPROTOOPT;
 		return (-1);
 	}
diff --git a/src/core/socket.c b/src/core/socket.c
index bf97ef8d..440f1bbf 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -37,7 +37,6 @@ struct nni_socket {
 	nni_mtx       s_mx;
 	nni_cv        s_cv;
 	nni_cv        s_close_cv;
-	int           s_raw;
 
 	uint64_t s_id;
 	uint32_t s_flags;
@@ -249,12 +248,6 @@ nni_sock_setopt_sockname(nni_sock *s, const void *buf, size_t sz)
 	return (0);
 }
 
-static int
-nni_sock_getopt_domain(nni_sock *s, void *buf, size_t *szp)
-{
-	return (nni_getopt_int(s->s_raw + 1, buf, szp));
-}
-
 static const nni_socket_option nni_sock_options[] = {
 	{
 	    .so_name   = NNG_OPT_RECVTIMEO,
@@ -301,11 +294,6 @@ static const nni_socket_option nni_sock_options[] = {
 	    .so_getopt = nni_sock_getopt_sockname,
 	    .so_setopt = nni_sock_setopt_sockname,
 	},
-	{
-	    .so_name   = NNG_OPT_DOMAIN,
-	    .so_getopt = nni_sock_getopt_domain,
-	    .so_setopt = NULL,
-	},
 	// terminate list
 	{ NULL, NULL, NULL },
 };
@@ -886,11 +874,6 @@ nni_sock_setopt(nni_sock *s, const char *name, const void *val, size_t size)
 			return (NNG_EREADONLY);
 		}
 		rv = pso->pso_setopt(s->s_data, val, size);
-		if ((rv == 0) && (strcmp(name, NNG_OPT_RAW) == 0) &&
-		    (size >= sizeof(int))) {
-			// Save the raw option -- we use this for the DOMAIN.
-			memcpy(&s->s_raw, val, sizeof(int));
-		}
 		nni_mtx_unlock(&s->s_mx);
 		return (rv);
 	}
diff --git a/src/nng.h b/src/nng.h
index a581d434..84680dd1 100644
--- a/src/nng.h
+++ b/src/nng.h
@@ -408,7 +408,6 @@ enum nng_flag_enum {
 
 // Options.
 #define NNG_OPT_SOCKNAME "socket-name"
-#define NNG_OPT_DOMAIN "compat:domain" // legacy compat only
 #define NNG_OPT_RAW "raw"
 #define NNG_OPT_LINGER "linger"
 #define NNG_OPT_RECVBUF "recv-buffer"
@@ -421,8 +420,6 @@ enum nng_flag_enum {
 #define NNG_OPT_REMADDR "remote-address"
 #define NNG_OPT_URL "url"
 #define NNG_OPT_MAXTTL "ttl-max"
-#define NNG_OPT_PROTOCOL "protocol"
-#define NNG_OPT_TRANSPORT "transport"
 #define NNG_OPT_RECVMAXSZ "recv-size-max"
 #define NNG_OPT_RECONNMINT "reconnect-time-min"
 #define NNG_OPT_RECONNMAXT "reconnect-time-max"
diff --git a/tests/sock.c b/tests/sock.c
index 1f7567f8..f1570fd8 100644
--- a/tests/sock.c
+++ b/tests/sock.c
@@ -88,8 +88,6 @@ TestMain("Socket Operations", {
 				    NNG_EREADONLY);
 				So(nng_setopt(s1, NNG_OPT_LOCADDR, "a", 1) ==
 				    NNG_EREADONLY);
-				So(nng_setopt_int(s1, NNG_OPT_DOMAIN, 3) ==
-				    NNG_EREADONLY);
 			});
 
 			Convey("Sockname option works", {
@@ -121,15 +119,13 @@ TestMain("Socket Operations", {
 				So(strcmp(name, "hello") == 0);
 			});
 
-			Convey("Domain option works", {
-				int dom;
-				So(nng_getopt_int(s1, NNG_OPT_DOMAIN, &dom) ==
-				    0);
-				So(dom == 1); // NN_AF_SP
+			Convey("RAW option works", {
+				int raw;
+				So(nng_getopt_int(s1, NNG_OPT_RAW, &raw) == 0);
+				So(raw == 0);
 				So(nng_setopt_int(s1, NNG_OPT_RAW, 1) == 0);
-				So(nng_getopt_int(s1, NNG_OPT_DOMAIN, &dom) ==
-				    0);
-				So(dom == 2); // NN_AF_SP_RAW
+				So(nng_getopt_int(s1, NNG_OPT_RAW, &raw) == 0);
+				So(raw == 1);
 			});
 
 			Convey("URL option works", {