erl_interface: Remove old distribution handshake

5 files changed, 107 insertions, 383 deletions

diff --git a/lib/erl_interface/src/connect/ei_connect.c b/lib/erl_interface/src/connect/ei_connect.c
index 8cdb5a97ee..4280b8f62e 100644
--- a/lib/erl_interface/src/connect/ei_connect.c
+++ b/lib/erl_interface/src/connect/ei_connect.c
@@ -103,8 +103,6 @@ static int recv_challenge(ei_socket_callbacks *cbs, void *ctx, int pkt_sz,
 static int send_challenge_reply(ei_socket_callbacks *cbs, void *ctx,
                                 int pkt_sz, unsigned char digest[16], 
 				unsigned challenge, unsigned ms);
-static int recv_complement(ei_socket_callbacks *cbs, void *ctx,
-                           int pkt_sz, unsigned ms);
 static int recv_challenge_reply(ei_socket_callbacks *cbs, void *ctx,
                                 int pkt_sz, unsigned our_challenge,
 				char cookie[], 
@@ -115,13 +113,9 @@ static int send_challenge_ack(ei_socket_callbacks *cbs, void *ctx,
 static int recv_challenge_ack(ei_socket_callbacks *cbs, void *ctx, 
 			      int pkt_sz, unsigned our_challenge,
 			      char cookie[], unsigned ms);
-static int send_name(ei_cnode *ec, void *ctx, int pkt_sz,
-                     unsigned version, unsigned ms);
-static int send_complement(ei_cnode *ec, void *ctx, int pkt_sz,
-                            unsigned epmd_says_version, DistFlags her_flags,
-                            unsigned ms);
+static int send_name(ei_cnode *ec, void *ctx, int pkt_sz, unsigned ms);
 static int recv_name(ei_socket_callbacks *cbs, void *ctx, int pkt_sz,
-                     char* send_name_tag, DistFlags *flags,
+                     DistFlags *flags,
                      char *namebuf, unsigned ms);
 static int ei_connect_helper(ei_cnode* ec,
                              Erl_IpAddr ip_addr,
@@ -1220,7 +1214,6 @@ static int ei_connect_helper(ei_cnode* ec,
     ei_socket_callbacks *cbs = ec->cbs;
     void *ctx;
     int sockd;
-    unsigned her_version;
     DistFlags her_flags;
     unsigned our_challenge, her_challenge;
     unsigned char our_digest[16];
@@ -1245,12 +1238,6 @@ static int ei_connect_helper(ei_cnode* ec,
 	return ERL_ERROR;
     }
 
-    if (!ec->thisnodename[0] && epmd_says_version < EI_DIST_6) {
-        /* This is a dynamic node name. We have to use at least vsn 6
-           of the dist protocol for this to work. */
-        epmd_says_version = EI_DIST_6;
-    }
-
     err = ei_socket_ctx__(cbs, &ctx, ec->setup_context);
     if (err) {
         EI_TRACE_ERR2("ei_xconnect","-> SOCKET failed: %s (%d)",
@@ -1287,24 +1274,21 @@ static int ei_connect_helper(ei_cnode* ec,
         goto error;
     }
         
-    if (send_name(ec, ctx, pkt_sz, epmd_says_version, tmo))
+    if (send_name(ec, ctx, pkt_sz, tmo))
         goto error;
     if (recv_status(ec, ctx, pkt_sz, tmo))
         goto error;
     if (recv_challenge(cbs, ctx, pkt_sz, &her_challenge,
                        &her_flags, NULL, tmo))
         goto error;
-    her_version = (her_flags & DFLAG_HANDSHAKE_23) ? EI_DIST_6 : EI_DIST_5;
     our_challenge = gen_challenge();
     gen_digest(her_challenge, ec->ei_connect_cookie, our_digest);
-    if (send_complement(ec, ctx, pkt_sz, epmd_says_version, her_flags, tmo))
-        goto error;
     if (send_challenge_reply(cbs, ctx, pkt_sz, our_digest, our_challenge, tmo))
         goto error;
     if (recv_challenge_ack(cbs, ctx, pkt_sz, our_challenge, 
                            ec->ei_connect_cookie, tmo))
         goto error;
-    if (put_ei_socket_info(sockd, her_version, null_cookie, ec, cbs, ctx) != 0)
+    if (put_ei_socket_info(sockd, EI_DIST_6, null_cookie, ec, cbs, ctx) != 0)
         goto error;
 
     if (cbs->connect_handshake_complete) {
@@ -1547,7 +1531,6 @@ int ei_accept_tmo(ei_cnode* ec, int lfd, ErlConnect *conp, unsigned ms)
     int fd;
     DistFlags her_flags;
     char tmp_nodename[MAXNODELEN+1];
-    char send_name_tag;
     char *her_name;
     int pkt_sz, err;
     struct sockaddr_in addr;
@@ -1622,14 +1605,12 @@ int ei_accept_tmo(ei_cnode* ec, int lfd, ErlConnect *conp, unsigned ms)
     
     EI_TRACE_CONN0("ei_accept","<- ACCEPT connected to remote");
     
-    if (recv_name(cbs, ctx, pkt_sz, &send_name_tag, &her_flags,
-                  her_name, tmo)) {
+    if (recv_name(cbs, ctx, pkt_sz, &her_flags, her_name, tmo)) {
 	EI_TRACE_ERR0("ei_accept","<- ACCEPT initial ident failed");
 	goto error;
     }
     
     {
-        unsigned her_version = (her_flags & DFLAG_HANDSHAKE_23) ? 6 : 5;
 	unsigned our_challenge;
 	unsigned her_challenge;
 	unsigned char our_digest[16];
@@ -1639,17 +1620,13 @@ int ei_accept_tmo(ei_cnode* ec, int lfd, ErlConnect *conp, unsigned ms)
 	our_challenge = gen_challenge();
 	if (send_challenge(ec, ctx, pkt_sz, our_challenge, her_flags, tmo))
 	    goto error;
-        if (send_name_tag == 'n' && (her_flags & DFLAG_HANDSHAKE_23)) {
-            if (recv_complement(cbs, ctx, pkt_sz, tmo))
-                goto error;
-        }
 	if (recv_challenge_reply(cbs, ctx, pkt_sz, our_challenge, 
                                  ec->ei_connect_cookie, &her_challenge, tmo))
 	    goto error;
 	gen_digest(her_challenge, ec->ei_connect_cookie, our_digest);
 	if (send_challenge_ack(cbs, ctx, pkt_sz, our_digest, tmo))
 	    goto error;
-	if (put_ei_socket_info(fd, her_version, null_cookie, ec, cbs, ctx) != 0)
+        if (put_ei_socket_info(fd, EI_DIST_6, null_cookie, ec, cbs, ctx) != 0)
             goto error;
     }
     if (conp) {
@@ -2285,7 +2262,6 @@ static DistFlags preferred_flags(void)
 static int send_name(ei_cnode *ec,
                      void *ctx,
                      int pkt_sz,
-                     unsigned version,
                      unsigned ms)
 {
     char *buf;
@@ -2297,25 +2273,18 @@ static int send_name(ei_cnode *ec,
     int err, ret;
     ssize_t len;
     DistFlags flags = preferred_flags();
-    char tag;
 
     if (ec->thisnodename[0]) {
         name_ptr = ec->thisnodename;
-        tag = (version == EI_DIST_5) ? 'n' : 'N';
     }
     else {
         /* dynamic node name */
         name_ptr = ec->thishostname;
-        tag = 'N'; /* presume ver 6 */
         flags |= DFLAG_NAME_ME;
     }
 
     name_len = strlen(name_ptr);
-
-    if (tag == 'n')
-        siz = pkt_sz + 1 + 2 + 4 + name_len;
-    else
-        siz = pkt_sz + 1 + 8 + 4 + 2 + name_len;
+    siz = pkt_sz + 1 + 8 + 4 + 2 + name_len;
 
     buf = (siz > DEFBUF_SIZ) ? malloc(siz) : dbuf;
     if (!buf) {
@@ -2335,16 +2304,10 @@ static int send_name(ei_cnode *ec,
         goto done;
     }
 
-    put8(s, tag);
-    if (tag == 'n') {
-        put16be(s, EI_DIST_5); /* some impl (jinterface) demand ver==5 */
-        put32be(s, flags);
-    }
-    else { /* tag == 'N' */
-        put64be(s, flags);
-        put32be(s, ec->creation);
-        put16be(s, name_len);
-    }
+    put8(s, 'N');
+    put64be(s, flags);
+    put32be(s, ec->creation);
+    put16be(s, name_len);
     memcpy(s, name_ptr, name_len);
     len = (ssize_t) siz;
     err = ei_write_fill_ctx_t__(ec->cbs, ctx, buf, &len, ms);
@@ -2379,12 +2342,8 @@ static int send_challenge(ei_cnode *ec,
     int err, ret;
     ssize_t len;
     DistFlags flags;
-    const char tag = (her_flags & DFLAG_HANDSHAKE_23) ? 'N' : 'n';
 
-    if (tag == 'n')
-        siz = pkt_sz + 1 + 2 + 4 + 4 + nodename_len;
-    else
-        siz = pkt_sz + 1 + 8 + 4 + 4 + 2 + nodename_len;
+    siz = pkt_sz + 1 + 8 + 4 + 4 + 2 + nodename_len;
 
     buf = (siz > DEFBUF_SIZ) ? malloc(siz) : dbuf;
     if (!buf) {
@@ -2405,18 +2364,11 @@ static int send_challenge(ei_cnode *ec,
     }
 
     flags = preferred_flags();
-    put8(s, tag);
-    if (tag == 'n') {
-        put16be(s, EI_DIST_5);  /* chosen version */
-        put32be(s, flags);
-        put32be(s, challenge);
-    }
-    else {
-        put64be(s, flags);
-        put32be(s, challenge);
-        put32be(s, ec->creation);
-        put16be(s, nodename_len);
-    }
+    put8(s, 'N');
+    put64be(s, flags);
+    put32be(s, challenge);
+    put32be(s, ec->creation);
+    put16be(s, nodename_len);
     memcpy(s, ec->thisnodename, nodename_len);
     len = (ssize_t) siz;
     err = ei_write_fill_ctx_t__(ec->cbs, ctx, buf, &len, ms);
@@ -2444,7 +2396,6 @@ static int recv_challenge(ei_socket_callbacks *cbs, void *ctx,
     int is_static = 1;
     int buflen = DEFBUF_SIZ;
     int rlen, nodename_len;
-    unsigned version;
     char *s;
     char tag;
     char tmp_nodename[MAXNODELEN+1];
@@ -2459,47 +2410,26 @@ static int recv_challenge(ei_socket_callbacks *cbs, void *ctx,
     }
     s = buf;
     tag = get8(s);
-    if (tag != 'n' && tag != 'N') {
+    if (tag != 'N') {
 	EI_TRACE_ERR2("recv_challenge",
 		      "<- RECV_CHALLENGE incorrect tag, "
-		      "expected 'n' or 'N', got '%c' (%u)",tag,tag);
+		      "expected 'N', got '%c' (%u)", tag, tag);
 	goto error;
     }
-    if (tag == 'n') { /* OLD */
-        if (rlen < 1+2+4+4) {
-            EI_TRACE_ERR1("recv_challenge","<- RECV_CHALLENGE 'n' packet too short (%d)",
-                          rlen)
-            goto error;
-        }
-
-        version = get16be(s);
-        if (version != EI_DIST_5) {
-            EI_TRACE_ERR1("recv_challenge",
-                          "<- RECV_CHALLENGE 'n' incorrect version=%d",
-                          version);
-            goto error;
-        }
-        *flags = get32be(s);
-        *challenge = get32be(s);
-        nodename_len = (buf + rlen) - s;
-    }
-    else { /* NEW */
-        if (rlen < 1+8+4+4+2) {
-            EI_TRACE_ERR1("recv_challenge","<- RECV_CHALLENGE 'N' packet too short (%d)",
-                          rlen)
-            goto error;
-        }
-        version = EI_DIST_6;
-        *flags = get64be(s);
-        *challenge = get32be(s);
-        s += 4; /* ignore peer 'creation' */
-        nodename_len = get16be(s);
-        if (nodename_len > (buf + rlen) - s) {
-            EI_TRACE_ERR1("recv_challenge",
-                          "<- RECV_CHALLENGE 'N' nodename too long (%d)",
-                          nodename_len);
-            goto error;
-        }
+    if (rlen < 1+8+4+4+2) {
+        EI_TRACE_ERR1("recv_challenge","<- RECV_CHALLENGE 'N' packet too short (%d)",
+                      rlen)
+        goto error;
+    }
+    *flags = get64be(s);
+    *challenge = get32be(s);
+    s += 4; /* ignore peer 'creation' */
+    nodename_len = get16be(s);
+    if (nodename_len > (buf + rlen) - s) {
+        EI_TRACE_ERR1("recv_challenge",
+                      "<- RECV_CHALLENGE 'N' nodename too long (%d)",
+                      nodename_len);
+        goto error;
     }
 
     if (nodename_len > MAXNODELEN) {
@@ -2526,12 +2456,10 @@ static int recv_challenge(ei_socket_callbacks *cbs, void *ctx,
     
     if (!is_static)
 	free(buf);
-    EI_TRACE_CONN4("recv_challenge","<- RECV_CHALLENGE (ok) node = %s, "
-	    "version = %u, "
+    EI_TRACE_CONN3("recv_challenge","<- RECV_CHALLENGE (ok) node = %s, "
 	    "flags = %u, "
 	    "challenge = %d",
 	    namebuf,
-	    version,
 	    *flags,
 	    *challenge
 	    );
@@ -2543,63 +2471,6 @@ error:
     return -1;
 }
 
-static int send_complement(ei_cnode *ec,
-                            void *ctx,
-                            int pkt_sz,
-                            unsigned epmd_says_version,
-                            DistFlags her_flags,
-                            unsigned ms)
-{
-    int ret = 0;
-    if (epmd_says_version == EI_DIST_5 && (her_flags & DFLAG_HANDSHAKE_23)) {
-        char *buf;
-        unsigned char *s;
-        char dbuf[DEFBUF_SIZ];
-        int err;
-        ssize_t len;
-        unsigned int flagsHigh;
-        const int siz = pkt_sz + 1 + 4 + 4;
-
-        buf = (siz > DEFBUF_SIZ) ? malloc(siz) : dbuf;
-        if (!buf) {
-            erl_errno = ENOMEM;
-            return -1;
-        }
-        s = (unsigned char *)buf;
-        switch (pkt_sz) {
-        case 2:
-            put16be(s,siz - 2);
-            break;
-        case 4:
-            put32be(s,siz - 4);
-            break;
-        default:
-            ret = -1;
-            goto done;
-        }
-        flagsHigh = preferred_flags() >> 32;
-
-        put8(s, 'c');
-        put32be(s, flagsHigh);
-        put32be(s, ec->creation);
-
-        len = (ssize_t) siz;
-        err = ei_write_fill_ctx_t__(ec->cbs, ctx, buf, &len, ms);
-        if (!err && len != (ssize_t) siz)
-            err = EIO;
-        if (err) {
-            EI_TRACE_ERR0("send_name", "SEND_NAME -> socket write failed");
-            EI_CONN_SAVE_ERRNO__(err);
-            ret = -1;
-        }
-    done:
-        if (buf != dbuf)
-            free(buf);
-    }
-    return ret;
-}
-
-
 static int send_challenge_reply(ei_socket_callbacks *cbs, void *ctx,
                                 int pkt_sz, unsigned char digest[16], 
 				unsigned challenge, unsigned ms) 
@@ -2646,54 +2517,6 @@ static int send_challenge_reply(ei_socket_callbacks *cbs, void *ctx,
     return 0;
 }
 
-static int recv_complement(ei_socket_callbacks *cbs,
-                           void *ctx,
-                           int pkt_sz,
-                           unsigned ms)
-{
-    char dbuf[DEFBUF_SIZ];
-    char *buf = dbuf;
-    int is_static = 1;
-    int buflen = DEFBUF_SIZ;
-    int rlen;
-    char *s;
-    char tag;
-    unsigned int creation;
-
-    erl_errno = EIO;		/* Default */
-
-    if ((rlen = read_hs_package(cbs, ctx, pkt_sz, &buf, &buflen, &is_static, ms)) != 21) {
-	EI_TRACE_ERR1("recv_complement",
-		      "<- RECV_COMPLEMENT socket read failed (%d)",rlen);
-	goto error;
-    }
-
-    s = buf;
-    if ((tag = get8(s)) != 'c') {
-	EI_TRACE_ERR2("recv_complement",
-		      "<- RECV_COMPLEMENT incorrect tag, "
-		      "expected 'c' got '%c' (%u)",tag,tag);
-	goto error;
-    }
-    creation = get32be(s);
-    if (!is_static)
-	free(buf);
-
-    if (ei_tracelevel >= 3) {
-        EI_TRACE_CONN1("recv_complement",
-                       "<- RECV_COMPLEMENT (ok) creation = %u",
-                       creation);
-    }
-    /* We don't have any use for 'creation' of other node, so we drop it */
-    erl_errno = 0;
-    return 0;
-
-error:
-    if (!is_static)
-	free(buf);
-    return -1;
-}
-
 static int recv_challenge_reply(ei_socket_callbacks *cbs,
                                 void *ctx,
                                 int pkt_sz,
@@ -2850,7 +2673,7 @@ error:
 }
 
 static int recv_name(ei_socket_callbacks *cbs, void *ctx,
-                     int pkt_sz, char *send_name_tag,
+                     int pkt_sz,
                      DistFlags *flags, char *namebuf, unsigned ms)
 {
     char dbuf[DEFBUF_SIZ];
@@ -2872,38 +2695,19 @@ static int recv_name(ei_socket_callbacks *cbs, void *ctx,
     }
     s = buf;
     tag = get8(s);
-    *send_name_tag = tag;
-    if (tag != 'n' && tag != 'N') {
+    if (tag != 'N') {
 	EI_TRACE_ERR2("recv_name","<- RECV_NAME incorrect tag, "
-		      "expected 'n' or 'N', got '%c' (%u)",tag,tag);
+		      "expected 'N', got '%c' (%u)",tag,tag);
 	goto error;
     }
-    if (tag == 'n') {
-        unsigned int version;
-        if (rlen < 1+2+4) {
-            EI_TRACE_ERR1("recv_name","<- RECV_NAME 'n' packet too short (%d)",
-                          rlen)
-            goto error;
-        }
-        version = get16be(s);
-        if (version < EI_DIST_5) {
-            EI_TRACE_ERR1("recv_name","<- RECV_NAME 'n' invalid version=%d",
-                          version)
-            goto error;
-        }
-        *flags = get32be(s);
-        namelen = rlen - (1+2+4);
-    }
-    else { /* tag == 'N' */
-        if (rlen < 1+8+4+2) {
-            EI_TRACE_ERR1("recv_name","<- RECV_NAME 'N' packet too short (%d)",
-                          rlen)
-            goto error;
-        }
-        *flags = get64be(s);
-        s += 4; /* ignore peer 'creation' */
-        namelen = get16be(s);
+    if (rlen < 1+8+4+2) {
+        EI_TRACE_ERR1("recv_name","<- RECV_NAME 'N' packet too short (%d)",
+                      rlen)
+        goto error;
     }
+    *flags = get64be(s);
+    s += 4; /* ignore peer 'creation' */
+    namelen = get16be(s);
 
     if (*flags & DFLAG_MANDATORY_25_DIGEST) {
         *flags |= DFLAG_DIST_MANDATORY_25;
@@ -2920,8 +2724,8 @@ static int recv_name(ei_socket_callbacks *cbs, void *ctx,
         namebuf = &tmp_nodename[0];
     
     if (namelen > MAXNODELEN || s+namelen > buf+rlen) {
-        EI_TRACE_ERR2("recv_name","<- RECV_NAME '%c' nodename too long (%d)",
-                      tag, namelen);
+        EI_TRACE_ERR1("recv_name","<- RECV_NAME nodename too long (%d)",
+                      namelen);
         goto error;
     }
 
@@ -2930,9 +2734,9 @@ static int recv_name(ei_socket_callbacks *cbs, void *ctx,
 
     if (!is_static)
 	free(buf);
-    EI_TRACE_CONN3("recv_name",
-		   "<- RECV_NAME (ok) node = %s, tag = %c, flags = %u",
-		   namebuf,tag,*flags);
+    EI_TRACE_CONN2("recv_name",
+		   "<- RECV_NAME (ok) node = %s, flags = %u",
+		   namebuf, *flags);
     erl_errno = 0;
     return 0;
     
diff --git a/lib/erl_interface/src/epmd/ei_epmd.h b/lib/erl_interface/src/epmd/ei_epmd.h
index 6a274b606a..1b234fb34d 100644
--- a/lib/erl_interface/src/epmd/ei_epmd.h
+++ b/lib/erl_interface/src/epmd/ei_epmd.h
@@ -24,12 +24,11 @@
 #define INADDR_LOOPBACK ((u_long) 0x7F000001)
 #endif
 
-#define EI_DIST_5 5 /* OTP R4 - 22 */
 #define EI_DIST_6 6 /* OTP 23 and later */
 
 #ifndef EI_DIST_HIGH
 #define EI_DIST_HIGH EI_DIST_6
-#define EI_DIST_LOW  EI_DIST_5
+#define EI_DIST_LOW  EI_DIST_6
 #endif
 
 #ifndef EPMD_PORT
diff --git a/lib/erl_interface/src/epmd/epmd_publish.c b/lib/erl_interface/src/epmd/epmd_publish.c
index 3e251d6a64..ff7f3f5323 100644
--- a/lib/erl_interface/src/epmd/epmd_publish.c
+++ b/lib/erl_interface/src/epmd/epmd_publish.c
@@ -76,8 +76,8 @@ static int ei_epmd_r4_publish (int port, const char *alive, unsigned ms)
   put16be(s,port); /* port number */
   put8(s,'h');            /* h = r4 hidden node */
   put8(s, EI_MYPROTO);      /* protocol 0 ?? */
-  put16be(s,EI_DIST_HIGH);   /* highest understood version: 1 = R4 */
-  put16be(s,EI_DIST_LOW);    /* lowest:  0 = R3 */
+  put16be(s,EI_DIST_HIGH);   /* highest understood version */
+  put16be(s,EI_DIST_LOW);    /* lowest */
   put16be(s,nlen);        /* length of alivename */
   strcpy(s, alive);
   s += nlen;
diff --git a/lib/erl_interface/test/ei_tmo_SUITE.erl b/lib/erl_interface/test/ei_tmo_SUITE.erl
index 49e889bdf3..964ec121f4 100644
--- a/lib/erl_interface/test/ei_tmo_SUITE.erl
+++ b/lib/erl_interface/test/ei_tmo_SUITE.erl
@@ -95,7 +95,8 @@ end_per_testcase(_Case, _Config) ->
              ?DFLAG_NEW_FLOATS bor
              ?DFLAG_MAP_TAG bor
              ?DFLAG_EXPORT_PTR_TAG bor
-             ?DFLAG_BIT_BINARIES)).
+             ?DFLAG_BIT_BINARIES bor
+             ?DFLAG_HANDSHAKE_23)).
 
 %% Check the framework.
 framework_check(Config) when is_list(Config) ->
@@ -142,7 +143,7 @@ do_one_recv_failure(Config,CNode) ->
     true = (Ret < 0),
     runner:recv_eot(P1).
 
--define(EI_DIST_LOW, 5).
+-define(EI_DIST_LOW, 6).
 -define(EI_DIST_HIGH, 6).
 
 %% Check send with timeouts.
@@ -176,15 +177,11 @@ do_one_send(Config,From,CNode) ->
 
 ei_send_failure_tmo(Config) when is_list(Config) ->
     register(ei_send_tmo_1,self()),
-    [begin
-         io:format("Test dist version ~p\n", [Ver]),
-         do_one_send_failure(Config,self(),cccc1,c_nod_send_tmo_3, Ver),
-         do_one_send_failure(Config,ei_send_tmo_1,cccc2,c_nod_send_tmo_4, Ver)
-     end
-     || Ver <- lists:seq(?EI_DIST_LOW, ?EI_DIST_HIGH)],
+    do_one_send_failure(Config,self(),cccc1,c_nod_send_tmo_3),
+    do_one_send_failure(Config,ei_send_tmo_1,cccc2,c_nod_send_tmo_4),
     ok.
 
-do_one_send_failure(Config,From,FakeName,CName, OurVer) ->
+do_one_send_failure(Config,From,FakeName,CName) ->
     {_,Host} = split(node()),
     OurName = join(FakeName,Host),
     Node = join(CName,Host),
@@ -194,7 +191,7 @@ do_one_send_failure(Config,From,FakeName,CName, OurVer) ->
                   Else ->
                       exit(Else)
               end,
-    EpmdSocket = epmd_register(OurName, LSocket, OurVer),
+    EpmdSocket = epmd_register(OurName, LSocket),
     P3 = runner:start(Config, ?send_tmo),
     Cookie = kaksmula_som_ingen_bryr_sig_om,
     runner:send_term(P3,{CName,
@@ -207,10 +204,10 @@ do_one_send_failure(Config,From,FakeName,CName, OurVer) ->
                   Else2 ->
                       exit(Else2)
               end,
-    {hidden,Node} = recv_name(SocketB, OurVer),  % See 1)
+    {hidden,Node} = recv_name(SocketB),  % See 1)
     send_status(SocketB, ok),
     MyChallengeB = gen_challenge(),
-    send_challenge(SocketB, OurName, MyChallengeB, OurVer),
+    send_challenge(SocketB, OurName, MyChallengeB),
     HisChallengeB = recv_challenge_reply(SocketB,
                                          MyChallengeB,
                                          Cookie),
@@ -256,18 +253,6 @@ ei_connect_unreachable_tmo(Config) when is_list(Config) ->
     ok.
 
 ei_connect_tmo(Config) when is_list(Config) ->
-    [begin
-         io:format("Test dist version ~p published as ~p\n",
-                   [OurVer,OurEpmdVer]),
-         do_ei_connect_tmo(Config, OurVer, OurEpmdVer)
-     end
-     || OurVer <- lists:seq(?EI_DIST_LOW, ?EI_DIST_HIGH),
-        OurEpmdVer <- lists:seq(?EI_DIST_LOW, ?EI_DIST_HIGH),
-        OurVer >= OurEpmdVer],
-
-    ok.
-
-do_ei_connect_tmo(Config, OurVer, OurEpmdVer) ->
     Flags = ?COMPULSORY_DFLAGS bor ?DFLAG_MANDATORY_25_DIGEST,
 
     P2 = runner:start(Config, ?connect_tmo),
@@ -289,7 +274,7 @@ do_ei_connect_tmo(Config, OurVer, OurEpmdVer) ->
                   Else ->
                       exit(Else)
               end,
-    EpmdSocket = epmd_register(OurName, LSocket, OurEpmdVer),
+    EpmdSocket = epmd_register(OurName, LSocket),
     P3 = runner:start(Config, ?connect_tmo),
     Cookie = kaksmula_som_ingen_bryr_sig_om,
     runner:send_term(P3,{c_nod_connect_tmo_3,
@@ -302,11 +287,10 @@ do_ei_connect_tmo(Config, OurVer, OurEpmdVer) ->
                   Else2 ->
                       exit(Else2)
               end,
-    {hidden,Node} = recv_name(SocketB, OurEpmdVer),  % See 1)
+    {hidden,Node} = recv_name(SocketB),  % See 1)
     send_status(SocketB, ok),
     MyChallengeB = gen_challenge(),
-    send_challenge(SocketB, OurName, MyChallengeB, OurVer, Flags),
-    recv_complement(SocketB, OurVer, OurEpmdVer),
+    send_challenge(SocketB, OurName, MyChallengeB, Flags),
     _HisChallengeB = recv_challenge_reply(SocketB,
                                           MyChallengeB,
                                           Cookie),
@@ -319,17 +303,6 @@ do_ei_connect_tmo(Config, OurVer, OurEpmdVer) ->
 
 %% Check accept with timeouts.
 ei_accept_tmo(Config) when is_list(Config) ->
-    [begin
-         io:format("Test our dist ver=~p and assumed ver=~p\n",
-                   [OurVer, AssumedVer]),
-         do_ei_accept_tmo(Config, OurVer, AssumedVer)
-     end
-     || OurVer <- lists:seq(?EI_DIST_LOW, ?EI_DIST_HIGH),
-        AssumedVer <- lists:seq(?EI_DIST_LOW, ?EI_DIST_HIGH),
-        OurVer >= AssumedVer],
-    ok.
-
-do_ei_accept_tmo(Config, OurVer, AssumedVer) ->
     Flags = ?COMPULSORY_DFLAGS bor ?DFLAG_MANDATORY_25_DIGEST,
 
     P = runner:start(Config, ?accept_tmo),
@@ -350,11 +323,11 @@ do_ei_accept_tmo(Config, OurVer, AssumedVer) ->
     runner:recv_eot(P2),
     true = is_integer(X),
 
-    normal_accept(Config, OurVer, AssumedVer, Flags),
+    normal_accept(Config, Flags),
 
     ok.
 
-normal_accept(Config, OurVer, AssumedVer, Flags) ->
+normal_accept(Config, Flags) ->
     P = runner:start(Config, ?accept_tmo),
     runner:send_term(P,{c_nod_som_vi_kontaktar_2,
                          erlang:get_cookie(),
@@ -368,9 +341,9 @@ normal_accept(Config, OurVer, AssumedVer, Flags) ->
     {ok, SocketA} = gen_tcp:connect(atom_to_list(NB),PortNo,
                                     [{active,false},
                                      {packet,2}]),
-    send_name(SocketA, OurName, OurVer, AssumedVer, Flags),
+    send_name(SocketA, OurName, Flags),
     ok = recv_status(SocketA),
-    {hidden,_Node,HisChallengeA} = recv_challenge(SocketA,OurVer), % See 1)
+    {hidden,_Node,HisChallengeA} = recv_challenge(SocketA), % See 1)
     _OurChallengeA = gen_challenge(),
     _OurDigestA = gen_digest(HisChallengeA, erlang:get_cookie()),
     %% Dont do the last two steps of the connection setup...
@@ -380,7 +353,7 @@ normal_accept(Config, OurVer, AssumedVer, Flags) ->
     runner:recv_eot(P),
     gen_tcp:close(SocketA).
 
-normal_connect(Config, OurVer, Flags) ->
+normal_connect(Config, Flags) ->
     {_,Host} = split(node()),
     OurName = join(cccc,Host),
     Node = join(c_nod_connect_tmo_3,Host),
@@ -390,7 +363,7 @@ normal_connect(Config, OurVer, Flags) ->
                   Else ->
                       exit(Else)
               end,
-    EpmdSocket = epmd_register(OurName, LSocket, OurVer),
+    EpmdSocket = epmd_register(OurName, LSocket),
     P3 = runner:start(Config, ?connect_tmo),
     Cookie = kaksmula_som_ingen_bryr_sig_om,
     runner:send_term(P3, {c_nod_connect_tmo_3,
@@ -403,11 +376,10 @@ normal_connect(Config, OurVer, Flags) ->
                   Else2 ->
                       exit(Else2)
               end,
-    {hidden,Node} = recv_name(SocketB, OurVer),
+    {hidden,Node} = recv_name(SocketB),
     send_status(SocketB, ok),
     MyChallengeB = gen_challenge(),
-    send_challenge(SocketB, OurName, MyChallengeB, OurVer, Flags),
-    recv_complement(SocketB, OurVer, OurVer),
+    send_challenge(SocketB, OurName, MyChallengeB, Flags),
     gen_tcp:close(SocketB),
     gen_tcp:close(EpmdSocket),
     ok.
@@ -429,20 +401,13 @@ make_and_check_dummy() ->
 
 %% Test that erl_interface sets the appropriate distributions flags.
 ei_dflags(Config) ->
-    AssumedVer = 5,
-    OurVer = 6,
-
     %% Test compatibility with OTP 24 and earlier.
-    normal_connect(Config, AssumedVer, ?COMPULSORY_DFLAGS),
-    normal_connect(Config, OurVer, ?COMPULSORY_DFLAGS),
-    normal_accept(Config, OurVer, AssumedVer, ?COMPULSORY_DFLAGS),
-    normal_accept(Config, OurVer, OurVer, ?COMPULSORY_DFLAGS),
+    normal_connect(Config, ?COMPULSORY_DFLAGS),
+    normal_accept(Config, ?COMPULSORY_DFLAGS),
 
     %% Test compatibility with future versions.
-    normal_connect(Config, AssumedVer, ?DFLAG_MANDATORY_25_DIGEST),
-    normal_connect(Config, OurVer, ?DFLAG_MANDATORY_25_DIGEST),
-    normal_accept(Config, OurVer, AssumedVer, ?DFLAG_MANDATORY_25_DIGEST),
-    normal_accept(Config, OurVer, OurVer, ?DFLAG_MANDATORY_25_DIGEST),
+    normal_connect(Config, ?DFLAG_MANDATORY_25_DIGEST),
+    normal_accept(Config, ?DFLAG_MANDATORY_25_DIGEST),
 
     ok.
 
@@ -518,40 +483,25 @@ recv_status(Socket) ->
             exit(Bad)
     end.
 
-send_challenge(Socket, Node, Challenge, OurVer) ->
+send_challenge(Socket, Node, Challenge) ->
     DefaultFlags = ?COMPULSORY_DFLAGS bor ?DFLAG_MANDATORY_25_DIGEST,
-    send_challenge(Socket, Node, Challenge, OurVer, DefaultFlags).
-
-send_challenge(Socket, Node, Challenge, OurVer, Flags) ->
-    if OurVer =:= 5 ->
-            ?to_port(Socket, [$n, ?int16(OurVer), ?int32(Flags),
-                              ?int32(Challenge), atom_to_list(Node)]);
-       OurVer >= 6 ->
-            NodeName = atom_to_binary(Node, latin1),
-            NameLen = byte_size(NodeName),
-            Creation = erts_internal:get_creation(),
-            ?to_port(Socket, [$N,
-                              <<(Flags bor ?DFLAG_HANDSHAKE_23):64,
-                                Challenge:32,
-                                Creation:32,
-                                NameLen:16>>,
-                              NodeName])
-    end.       
-
-recv_challenge(Socket, OurVer) ->
+    send_challenge(Socket, Node, Challenge, DefaultFlags).
+
+send_challenge(Socket, Node, Challenge, Flags) ->
+    NodeName = atom_to_binary(Node, latin1),
+    NameLen = byte_size(NodeName),
+    Creation = erts_internal:get_creation(),
+    ?to_port(Socket, [$N,
+                      << Flags:64,
+                         Challenge:32,
+                         Creation:32,
+                         NameLen:16>>,
+                      NodeName]).
+
+recv_challenge(Socket) ->
     case gen_tcp:recv(Socket, 0) of
-        {ok,[$n,V1,V0,Fl1,Fl2,Fl3,Fl4,CA3,CA2,CA1,CA0 | Ns]} ->
-            5 = OurVer,
-            Flags = ?u32(Fl1,Fl2,Fl3,Fl4),
-            Type = flags_to_type(Flags),
-            Node =list_to_atom(Ns),
-            OurVer = ?u16(V1,V0),  % echoed back
-            Challenge = ?u32(CA3,CA2,CA1,CA0),
-            {Type,Node,Challenge};
-
         {ok,[$N, F7,F6,F5,F4,F3,F2,F1,F0, CA3,CA2,CA1,CA0,
              _Cr3,_Cr2,_Cr1,_Cr0, NL1,NL0 | Rest]} ->
-            true = (OurVer >= 6),
             <<Flags:64>> = <<F7,F6,F5,F4,F3,F2,F1,F0>>,
             verify_flags(Flags),
             Type = flags_to_type(Flags),
@@ -608,34 +558,18 @@ send_challenge_ack(Socket, Digest) ->
 %            ?shutdown(bad_challenge_ack)
 %    end.
 
-send_name(Socket, MyNode, OurVer, AssumedVer, Flags0) ->
-    Flags = Flags0 bor case OurVer of
-                           5 -> 0;
-                           6 -> ?DFLAG_HANDSHAKE_23
-                       end,
+send_name(Socket, MyNode, Flags) ->
     NodeName = atom_to_binary(MyNode, latin1),
-    if AssumedVer =:= 5 ->
-            ?to_port(Socket, [$n,?int16(OurVer),?int32(Flags),NodeName]);
-       AssumedVer >= 6 ->
-            Creation = erts_internal:get_creation(),
-            ?to_port(Socket, [$N,
-                              <<Flags:64,
-                                Creation:32,
-                                (byte_size(NodeName)):16>>,
-                              NodeName])
-    end.
-
-recv_name(Socket, OurEpmdVer) ->
+    Creation = erts_internal:get_creation(),
+    ?to_port(Socket, [$N,
+                      <<Flags:64,
+                        Creation:32,
+                        (byte_size(NodeName)):16>>,
+                      NodeName]).
+
+recv_name(Socket) ->
     case gen_tcp:recv(Socket, 0) of
-        {ok,[$n, V1,V0, F3,F2,F1,F0 | OtherNode]} ->
-            5 = OurEpmdVer,
-            5 = ?u16(V1,V0),
-            Flags = ?u32(F3, F2, F1, F0),
-            verify_flags(Flags),
-            Type = flags_to_type(Flags),
-            {Type, list_to_atom(OtherNode)};
         {ok,[$N, F7,F6,F5,F4,F3,F2,F1,F0, _Cr3,_Cr2,_Cr1,_Cr0, NL1, NL0 | Rest]} ->
-            true = (OurEpmdVer >= 6),
             {OtherNode, _Residue} = lists:split(?u16(NL1,NL0), Rest),
             <<Flags:64>> = <<F7,F6,F5,F4,F3,F2,F1,F0>>,
             verify_flags(Flags),
@@ -645,17 +579,6 @@ recv_name(Socket, OurEpmdVer) ->
             ?shutdown({no_node,Res})
     end.
 
-recv_complement(Socket, OurVer, 5) when OurVer > 5 ->
-    case gen_tcp:recv(Socket, 0) of
-        {ok,[$c, _F7,_F6,_F5,_F4, _Cr3,_Cr2,_Cr1,_Cr0]} ->
-            ok;
-        Res ->
-            ?shutdown({no_node,Res})
-    end;
-recv_complement(_, _OurVer, _OurEpmdVer) ->
-    ok.
-
-
 %%
 %% tell_name is for old handshake
 %%
@@ -667,7 +590,7 @@ recv_complement(_, _OurVer, _OurEpmdVer) ->
 %%
 %% The communication with EPMD follows
 %%
-do_register_node(NodeName, TcpPort, VLow, VHigh) ->
+do_register_node(NodeName, TcpPort) ->
     case gen_tcp:connect({127,0,0,1}, get_epmd_port(), []) of
         {ok, Socket} ->
             {N0,_} = split(NodeName),
@@ -679,8 +602,8 @@ do_register_node(NodeName, TcpPort, VLow, VHigh) ->
                                   ?int16(TcpPort),
                                   $M,
                                   0,
-                                  ?int16(VHigh),
-                                  ?int16(VLow),
+                                  ?int16(?EI_DIST_HIGH),
+                                  ?int16(?EI_DIST_LOW),
                                   ?int16(length(Name)),
                                   Name,
                                   ?int16(Elen),
@@ -716,9 +639,9 @@ wait_for_reg_reply(Socket, SoFar) ->
     end.
 
 
-epmd_register(NodeName, ListenSocket, OurVer) ->
+epmd_register(NodeName, ListenSocket) ->
     {ok,{_,TcpPort}} = inet:sockname(ListenSocket),
-    case do_register_node(NodeName, TcpPort, ?EI_DIST_LOW, OurVer) of
+    case do_register_node(NodeName, TcpPort) of
         {alive, Socket, _Creation} ->
             Socket;
         Other ->
diff --git a/lib/kernel/include/dist.hrl b/lib/kernel/include/dist.hrl
index 3c2d6323e3..2cd2dd1fb4 100644
--- a/lib/kernel/include/dist.hrl
+++ b/lib/kernel/include/dist.hrl
@@ -75,11 +75,9 @@
 %% Also update dflag2str() in ../src/dist_util.erl
 %% when adding flags...
 
+-define(ERL_DIST_VER_6, 6).  % OTP-23 at least
 
--define(ERL_DIST_VER_5, 5).  % OTP-22 or (much) older
--define(ERL_DIST_VER_6, 6).  % OTP-23 (or maybe newer?)
-
--define(ERL_DIST_VER_LOW, ?ERL_DIST_VER_5).
+-define(ERL_DIST_VER_LOW, ?ERL_DIST_VER_6).
 -define(ERL_DIST_VER_HIGH, ?ERL_DIST_VER_6).
 
 %%%