Merge 'sverker/dist-handshake/OTP-16229' into master

6 files changed, 511 insertions, 182 deletions

diff --git a/lib/erl_interface/include/ei.h b/lib/erl_interface/include/ei.h
index 93c6b3dfa7..509fa444c4 100644
--- a/lib/erl_interface/include/ei.h
+++ b/lib/erl_interface/include/ei.h
@@ -362,7 +362,7 @@ typedef struct ei_cnode_s {
 /* Currently this_ipaddr isn't used */
 /*    struct in_addr this_ipaddr; */
     char ei_connect_cookie[EI_MAX_COOKIE_SIZE+1];
-    short creation;
+    unsigned int creation;
     erlang_pid self;
     ei_socket_callbacks *cbs;
     void *setup_context;
diff --git a/lib/erl_interface/src/connect/ei_connect.c b/lib/erl_interface/src/connect/ei_connect.c
index aab3043b9f..fee6927b95 100644
--- a/lib/erl_interface/src/connect/ei_connect.c
+++ b/lib/erl_interface/src/connect/ei_connect.c
@@ -106,7 +106,8 @@ int ei_tracelevel = 0;
     (offsetof(ei_socket_callbacks, get_fd)              \
      + sizeof(int (*)(void *)))
 
-/* FIXME why not macro? */
+typedef EI_ULONGLONG DistFlags;
+
 static char *null_cookie = "";
 
 static int get_cookie(char *buf, int len);
@@ -120,15 +121,17 @@ static int send_status(ei_socket_callbacks *cbs, void *ctx,
                        int pkt_sz, char *status, unsigned ms);
 static int recv_status(ei_socket_callbacks *cbs, void *ctx,
                        int pkt_sz, unsigned ms);
-static int send_challenge(ei_socket_callbacks *cbs, void *ctx, int pkt_sz,
-                          char *nodename, unsigned challenge,
-                          unsigned version, unsigned ms);
+static int send_challenge(ei_cnode *ec, void *ctx, int pkt_sz,
+                          unsigned challenge,
+                          DistFlags version, unsigned ms);
 static int recv_challenge(ei_socket_callbacks *cbs, void *ctx, int pkt_sz,
                           unsigned *challenge, unsigned *version,
-			  unsigned *flags, char *namebuf, unsigned ms);
+			  DistFlags *flags, char *namebuf, unsigned ms);
 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[], 
@@ -139,18 +142,20 @@ 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_socket_callbacks *cbs, void *ctx, int pkt_sz,
-                     char *nodename, unsigned version, 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 recv_name(ei_socket_callbacks *cbs, void *ctx, int pkt_sz,
-                     unsigned *version, unsigned *flags, char *namebuf,
-                     unsigned ms);
+                     char* send_name_tag, DistFlags *flags,
+                     char *namebuf, unsigned ms);
 static int ei_connect_helper(ei_cnode* ec,
                              Erl_IpAddr ip_addr,
                              char *alivename,
                              unsigned ms,
                              int rport,
-                             int dist);
+                             int epmd_says_version);
 
 static struct hostent*
 dyn_gethostbyname_r(const char *name, struct hostent *hostp, char **buffer_p,
@@ -956,12 +961,13 @@ static int ei_connect_helper(ei_cnode* ec,
                              char *alivename,
                              unsigned ms,
                              int rport,
-                             int dist)
+                             int epmd_says_version)
 {
     ei_socket_callbacks *cbs = ec->cbs;
     void *ctx;
     int sockd;
-    unsigned her_flags, her_version;
+    unsigned her_version;
+    DistFlags her_flags;
     unsigned our_challenge, her_challenge;
     unsigned char our_digest[16];
     int err;
@@ -979,8 +985,9 @@ static int ei_connect_helper(ei_cnode* ec,
                        rport);
     }
 
-    if (dist <= 4) {
-	EI_TRACE_ERR0("ei_xconnect","-> CONNECT remote version not compatible");
+    if (epmd_says_version < EI_DIST_LOW) {
+	EI_TRACE_ERR1("ei_xconnect","-> CONNECT remote version %d not compatible",
+                      epmd_says_version);
 	return ERL_ERROR;
     }
 
@@ -1020,21 +1027,24 @@ static int ei_connect_helper(ei_cnode* ec,
         goto error;
     }
         
-    if (send_name(cbs, ctx, pkt_sz, ec->thisnodename, (unsigned) dist, tmo))
+    if (send_name(ec, ctx, pkt_sz, epmd_says_version, tmo))
         goto error;
     if (recv_status(cbs, ctx, pkt_sz, tmo))
         goto error;
-    if (recv_challenge(cbs, ctx, pkt_sz, &her_challenge,
-                       &her_version, &her_flags, NULL, tmo))
+    if (recv_challenge(cbs, ctx, pkt_sz, &her_challenge, &her_version,
+                       &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, dist, null_cookie, ec, cbs, ctx) != 0)
+    if (put_ei_socket_info(sockd, her_version, null_cookie, ec, cbs, ctx) != 0)
         goto error;
 
     if (cbs->connect_handshake_complete) {
@@ -1134,15 +1144,15 @@ int ei_connect_host_port(ei_cnode* ec, char *host, int port)
 
 int ei_xconnect_tmo(ei_cnode* ec, Erl_IpAddr ip_addr, char *alivename, unsigned ms)
 {
-    int dist = 0;
+    int epmd_says_version = 0;
     int port;
     unsigned tmo = ms == 0 ? EI_SCLBK_INF_TMO : ms;
-    if ((port = ei_epmd_port_tmo(ip_addr,alivename,&dist, tmo)) < 0) {
+    if ((port = ei_epmd_port_tmo(ip_addr,alivename,&epmd_says_version, tmo)) < 0) {
 	EI_TRACE_ERR0("ei_xconnect","-> CONNECT can't get remote port");
 	/* ei_epmd_port_tmo() has set erl_errno */
 	return ERL_NO_PORT;
     }
-    return ei_connect_helper(ec, ip_addr, alivename, ms, port, dist);
+    return ei_connect_helper(ec, ip_addr, alivename, ms, port, epmd_says_version);
 }
 
 int ei_xconnect(ei_cnode* ec, Erl_IpAddr ip_addr, char *alivename)
@@ -1152,7 +1162,7 @@ int ei_xconnect(ei_cnode* ec, Erl_IpAddr ip_addr, char *alivename)
 
 int ei_xconnect_host_port_tmo(ei_cnode* ec, Erl_IpAddr ip_addr, int port, unsigned ms)
 {
-    return ei_connect_helper(ec, ip_addr, NULL, ms, port, 5);
+    return ei_connect_helper(ec, ip_addr, NULL, ms, port, EI_DIST_LOW);
 }
 
 int ei_xconnect_host_port(ei_cnode* ec, Erl_IpAddr ip_addr, int port)
@@ -1275,8 +1285,9 @@ int ei_accept(ei_cnode* ec, int lfd, ErlConnect *conp)
 int ei_accept_tmo(ei_cnode* ec, int lfd, ErlConnect *conp, unsigned ms)
 {
     int fd;
-    unsigned her_version, her_flags;
+    DistFlags her_flags;
     char tmp_nodename[MAXNODELEN+1];
+    char send_name_tag;
     char *her_name;
     int pkt_sz, err;
     struct sockaddr_in addr;
@@ -1301,6 +1312,10 @@ int ei_accept_tmo(ei_cnode* ec, int lfd, ErlConnect *conp, unsigned ms)
         ctx = EI_FD_AS_CTX__(lfd);
     }
 
+    if (ec->cbs != cbs) {
+        EI_CONN_SAVE_ERRNO__(EINVAL);
+        return ERL_ERROR;
+    }
 
     EI_TRACE_CONN0("ei_accept","<- ACCEPT waiting for connection");
 
@@ -1347,16 +1362,14 @@ 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, &her_version, &her_flags, her_name, tmo)) {
+    if (recv_name(cbs, ctx, pkt_sz, &send_name_tag, &her_flags,
+                  her_name, tmo)) {
 	EI_TRACE_ERR0("ei_accept","<- ACCEPT initial ident failed");
 	goto error;
     }
     
-    if (her_version <= 4) {
-	EI_TRACE_ERR0("ei_accept","<- ACCEPT remote version not compatible");
-	goto error;
-    }
-    else {
+    {
+        unsigned her_version = (her_flags & DFLAG_HANDSHAKE_23) ? 6 : 5;
 	unsigned our_challenge;
 	unsigned her_challenge;
 	unsigned char our_digest[16];
@@ -1364,9 +1377,12 @@ int ei_accept_tmo(ei_cnode* ec, int lfd, ErlConnect *conp, unsigned ms)
 	if (send_status(cbs, ctx, pkt_sz, "ok", tmo))
 	    goto error;
 	our_challenge = gen_challenge();
-	if (send_challenge(cbs, ctx, pkt_sz, ec->thisnodename, 
-                           our_challenge, her_version, tmo))
+	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;
@@ -1912,26 +1928,50 @@ error:
     return -1;
 }
 
-static int send_name_or_challenge(ei_socket_callbacks *cbs,
-                                  void *ctx,
-                                  int pkt_sz,
-                                  char *nodename,
-				  int f_chall,
-				  unsigned challenge,
-				  unsigned version,
-				  unsigned ms) 
+static DistFlags preferred_flags(void)
+{
+    DistFlags flags =
+        DFLAG_EXTENDED_REFERENCES
+        | DFLAG_DIST_MONITOR
+        | DFLAG_EXTENDED_PIDS_PORTS
+        | DFLAG_FUN_TAGS
+        | DFLAG_NEW_FUN_TAGS
+        | DFLAG_NEW_FLOATS
+        | DFLAG_SMALL_ATOM_TAGS
+        | DFLAG_UTF8_ATOMS
+        | DFLAG_MAP_TAG
+        | DFLAG_BIG_CREATION
+        | DFLAG_EXPORT_PTR_TAG
+        | DFLAG_BIT_BINARIES
+        | DFLAG_HANDSHAKE_23;
+    if (ei_internal_use_21_bitstr_expfun()) {
+        flags &= ~(DFLAG_EXPORT_PTR_TAG
+                   | DFLAG_BIT_BINARIES);
+    }
+    return flags;
+}
+
+static int send_name(ei_cnode *ec,
+                     void *ctx,
+                     int pkt_sz,
+                     unsigned version,
+                     unsigned ms)
 {
     char *buf;
     unsigned char *s;
     char dbuf[DEFBUF_SIZ];
-    int siz = pkt_sz + 1 + 2 + 4 + strlen(nodename);
-    const char* function[] = {"SEND_NAME", "SEND_CHALLENGE"};
+    const unsigned int nodename_len = strlen(ec->thisnodename);
+    int siz;
     int err;
     ssize_t len;
-    unsigned int flags;
+    DistFlags flags;
+    const char tag = (version == EI_DIST_5) ? 'n' : 'N';
+
+    if (tag == 'n')
+        siz = pkt_sz + 1 + 2 + 4 + nodename_len;
+    else
+        siz = pkt_sz + 1 + 8 + 4 + 2 + nodename_len;
 
-    if (f_chall)
-	siz += 4;
     buf = (siz > DEFBUF_SIZ) ? malloc(siz) : dbuf;
     if (!buf) {
 	erl_errno = ENOMEM;
@@ -1948,35 +1988,95 @@ static int send_name_or_challenge(ei_socket_callbacks *cbs,
     default:
         return -1;
     }
-    put8(s, 'n');
-    put16be(s, version);
-    flags = (DFLAG_EXTENDED_REFERENCES
-		| DFLAG_DIST_MONITOR
-		| DFLAG_EXTENDED_PIDS_PORTS
-		| DFLAG_FUN_TAGS
-		| DFLAG_NEW_FUN_TAGS
-                | DFLAG_NEW_FLOATS
-		| DFLAG_SMALL_ATOM_TAGS
-		| DFLAG_UTF8_ATOMS
-		| DFLAG_MAP_TAG
-		| DFLAG_BIG_CREATION
-                | DFLAG_EXPORT_PTR_TAG
-                | DFLAG_BIT_BINARIES);
-    if (ei_internal_use_21_bitstr_expfun()) {
-        flags &= ~(DFLAG_EXPORT_PTR_TAG
-                   | DFLAG_BIT_BINARIES);
+    flags = preferred_flags();
+
+    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, nodename_len);
     }
-    put32be(s, flags);
-    if (f_chall)
-	put32be(s, challenge);
-    memcpy(s, nodename, strlen(nodename));
+    memcpy(s, ec->thisnodename, nodename_len);
     len = (ssize_t) siz;
-    err = ei_write_fill_ctx_t__(cbs, ctx, buf, &len, ms);
+    err = ei_write_fill_ctx_t__(ec->cbs, ctx, buf, &len, ms);
     if (!err && len != (ssize_t) siz)
         err = EIO;
     if (err) {
-	EI_TRACE_ERR1("send_name_or_challenge",
-		      "-> %s socket write failed", function[f_chall]);
+	EI_TRACE_ERR0("send_name", "SEND_NAME -> socket write failed");
+	if (buf != dbuf)
+	    free(buf);
+        EI_CONN_SAVE_ERRNO__(err);
+	return -1;
+    }
+
+    if (buf != dbuf)
+	free(buf);
+    return 0;
+}
+
+static int send_challenge(ei_cnode *ec,
+                          void *ctx,
+                          int pkt_sz,
+                          unsigned challenge,
+                          DistFlags her_flags,
+                          unsigned ms)
+{
+    char *buf;
+    unsigned char *s;
+    char dbuf[DEFBUF_SIZ];
+    const unsigned int nodename_len = strlen(ec->thisnodename);
+    int siz;
+    int err;
+    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;
+
+    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:
+        return -1;
+    }
+
+    flags = preferred_flags();
+    put8(s, tag);
+    if (tag == 'n') {
+        put16be(s, EI_DIST_5);  /* choosen version */
+        put32be(s, flags);
+        put32be(s, challenge);
+    }
+    else {
+        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);
+    if (!err && len != (ssize_t) siz)
+        err = EIO;
+    if (err) {
+	EI_TRACE_ERR0("send_challenge", "-> SEND_CHALLENGE socket write failed");
 	if (buf != dbuf)
 	    free(buf);
         EI_CONN_SAVE_ERRNO__(err);
@@ -1990,13 +2090,13 @@ static int send_name_or_challenge(ei_socket_callbacks *cbs,
 
 static int recv_challenge(ei_socket_callbacks *cbs, void *ctx,
                           int pkt_sz, unsigned *challenge, unsigned *version,
-			  unsigned *flags, char *namebuf, unsigned ms)
+			  DistFlags *flags, char *namebuf, unsigned ms)
 {
     char dbuf[DEFBUF_SIZ];
     char *buf = dbuf;
     int is_static = 1;
     int buflen = DEFBUF_SIZ;
-    int rlen;
+    int rlen, nodename_len;
     char *s;
     char tag;
     char tmp_nodename[MAXNODELEN+1];
@@ -2009,21 +2109,57 @@ static int recv_challenge(ei_socket_callbacks *cbs, void *ctx,
 		      "<- RECV_CHALLENGE socket read failed (%d)",rlen);
 	goto error;
     }
-    if ((rlen - 11) > MAXNODELEN) {
-	EI_TRACE_ERR1("recv_challenge",
-		      "<- RECV_CHALLENGE nodename too long (%d)",rlen - 11);
-	goto error;
-    }
     s = buf;
-    if ((tag = get8(s)) != 'n') {
+    tag = get8(s);
+    if (tag != 'n' && tag != 'N') {
 	EI_TRACE_ERR2("recv_challenge",
 		      "<- RECV_CHALLENGE incorrect tag, "
-		      "expected 'n' got '%c' (%u)",tag,tag);
+		      "expected 'n' or 'N', got '%c' (%u)",tag,tag);
 	goto error;
     }
-    *version = get16be(s);
-    *flags = get32be(s);
-    *challenge = get32be(s);
+    if (tag == 'n') { /* OLD */
+        unsigned int version;
+        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 (nodename_len > MAXNODELEN) {
+        EI_TRACE_ERR1("recv_challenge",
+                      "<- RECV_CHALLENGE nodename too long (%d)", nodename_len);
+        goto error;
+    }
 
     if (!(*flags & DFLAG_EXTENDED_REFERENCES)) {
 	EI_TRACE_ERR0("recv_challenge","<- RECV_CHALLENGE peer cannot "
@@ -2047,8 +2183,8 @@ static int recv_challenge(ei_socket_callbacks *cbs, void *ctx,
     if (!namebuf)
         namebuf = &tmp_nodename[0];
     
-    memcpy(namebuf, s, rlen - 11);
-    namebuf[rlen - 11] = '\0';
+    memcpy(namebuf, s, nodename_len);
+    namebuf[nodename_len] = '\0';
     
     if (!is_static)
 	free(buf);
@@ -2069,6 +2205,63 @@ error:
     return -1;
 }
 
+static int send_complement(ei_cnode *ec,
+                            void *ctx,
+                            int pkt_sz,
+                            unsigned epmd_says_version,
+                            DistFlags her_flags,
+                            unsigned ms)
+{
+    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:
+            return -1;
+        }
+        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");
+            if (buf != dbuf)
+                free(buf);
+            EI_CONN_SAVE_ERRNO__(err);
+            return -1;
+        }
+
+        if (buf != dbuf)
+            free(buf);
+    }
+    return 0;
+}
+
+
 static int send_challenge_reply(ei_socket_callbacks *cbs, void *ctx,
                                 int pkt_sz, unsigned char digest[16], 
 				unsigned challenge, unsigned ms) 
@@ -2115,6 +2308,54 @@ 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,
@@ -2270,30 +2511,16 @@ error:
     return -1;
 }
 
-static int send_name(ei_socket_callbacks *cbs, void *ctx, int pkt_sz,
-                     char *nodename, unsigned version, unsigned ms) 
-{
-    return send_name_or_challenge(cbs, ctx, pkt_sz, nodename, 0,
-                                  0, version, ms);
-}
-
-static int send_challenge(ei_socket_callbacks *cbs, void *ctx, int pkt_sz,
-                          char *nodename, unsigned challenge, unsigned version,
-                          unsigned ms)
-{
-    return send_name_or_challenge(cbs, ctx, pkt_sz, nodename, 1,
-                                  challenge, version, ms);
-}
-
 static int recv_name(ei_socket_callbacks *cbs, void *ctx,
-                     int pkt_sz, unsigned *version,
-		     unsigned *flags, char *namebuf, unsigned ms)
+                     int pkt_sz, char *send_name_tag,
+                     DistFlags *flags, char *namebuf, unsigned ms)
 {
     char dbuf[DEFBUF_SIZ];
     char *buf = dbuf;
     int is_static = 1;
     int buflen = DEFBUF_SIZ;
     int rlen;
+    unsigned int namelen;
     char *s;
     char tmp_nodename[MAXNODELEN+1];
     char tag;
@@ -2305,19 +2532,40 @@ static int recv_name(ei_socket_callbacks *cbs, void *ctx,
 	EI_TRACE_ERR1("recv_name","<- RECV_NAME socket read failed (%d)",rlen);
 	goto error;
     }
-    if ((rlen - 7) > MAXNODELEN) {
-	EI_TRACE_ERR1("recv_name","<- RECV_NAME nodename too long (%d)",rlen-7);
-	goto error;
-    }
     s = buf;
     tag = get8(s);
-    if (tag != 'n') {
+    *send_name_tag = tag;
+    if (tag != 'n' && tag != 'N') {
 	EI_TRACE_ERR2("recv_name","<- RECV_NAME incorrect tag, "
-		      "expected 'n' got '%c' (%u)",tag,tag);
+		      "expected 'n' or 'N', got '%c' (%u)",tag,tag);
 	goto error;
     }
-    *version = get16be(s);
-    *flags = get32be(s);
+    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 (!(*flags & DFLAG_EXTENDED_REFERENCES)) {
 	EI_TRACE_ERR0("recv_name","<- RECV_NAME peer cannot handle"
@@ -2335,14 +2583,20 @@ static int recv_name(ei_socket_callbacks *cbs, void *ctx,
     if (!namebuf)
         namebuf = &tmp_nodename[0];
     
-    memcpy(namebuf, s, rlen - 7);
-    namebuf[rlen - 7] = '\0';
+    if (namelen > MAXNODELEN || s+namelen > buf+rlen) {
+        EI_TRACE_ERR2("recv_name","<- RECV_NAME '%c' nodename too long (%d)",
+                      tag, namelen);
+        goto error;
+    }
+
+    memcpy(namebuf, s, namelen);
+    namebuf[namelen] = '\0';
 
     if (!is_static)
 	free(buf);
     EI_TRACE_CONN3("recv_name",
-		   "<- RECV_NAME (ok) node = %s, version = %u, flags = %u",
-		   namebuf,*version,*flags);
+		   "<- RECV_NAME (ok) node = %s, tag = %c, flags = %u",
+		   namebuf,tag,*flags);
     erl_errno = 0;
     return 0;
     
diff --git a/lib/erl_interface/src/connect/ei_connect_int.h b/lib/erl_interface/src/connect/ei_connect_int.h
index b41a5f2b23..428713e015 100644
--- a/lib/erl_interface/src/connect/ei_connect_int.h
+++ b/lib/erl_interface/src/connect/ei_connect_int.h
@@ -109,6 +109,8 @@ extern int h_errno;
 #define DFLAG_UTF8_ATOMS          0x10000
 #define DFLAG_MAP_TAG             0x20000
 #define DFLAG_BIG_CREATION        0x40000
+#define DFLAG_HANDSHAKE_23       0x1000000
+#define DFLAG_HANDSHAKE_XX      0xfe000000 /* bits reserved for handshake changes */
 
 ei_cnode   *ei_fd_to_cnode(int fd);
 int         ei_distversion(int fd);
diff --git a/lib/erl_interface/src/epmd/ei_epmd.h b/lib/erl_interface/src/epmd/ei_epmd.h
index 597a955676..e3cb041dc9 100644
--- a/lib/erl_interface/src/epmd/ei_epmd.h
+++ b/lib/erl_interface/src/epmd/ei_epmd.h
@@ -24,9 +24,12 @@
 #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 6 /* OTP 23 and later */
-#define EI_DIST_LOW  5 /* OTP R4 - 22 */
+#define EI_DIST_HIGH EI_DIST_6
+#define EI_DIST_LOW  EI_DIST_5
 #endif
 
 #ifndef EPMD_PORT
diff --git a/lib/erl_interface/test/ei_accept_SUITE.erl b/lib/erl_interface/test/ei_accept_SUITE.erl
index ceb1e401ff..c49b8a358a 100644
--- a/lib/erl_interface/test/ei_accept_SUITE.erl
+++ b/lib/erl_interface/test/ei_accept_SUITE.erl
@@ -75,7 +75,8 @@ ei_accept_do(Config, CompatRel, SockImpl) ->
     {ok, ListenFd} = ei_publish(P, Port),
     {any, EINode} ! TermToSend,
 
-    {ok, Fd, _Node} = ei_accept(P, ListenFd),
+    {ok, Fd, Node} = ei_accept(P, ListenFd),
+    Node = node(),
     Got1 = ei_receive(P, Fd),
 
     %% Send again, now without auto-connect
diff --git a/lib/erl_interface/test/ei_tmo_SUITE.erl b/lib/erl_interface/test/ei_tmo_SUITE.erl
index cbb3f2cf30..8d8776949c 100644
--- a/lib/erl_interface/test/ei_tmo_SUITE.erl
+++ b/lib/erl_interface/test/ei_tmo_SUITE.erl
@@ -106,6 +106,8 @@ do_one_recv_failure(Config,CNode) ->
     true = (Ret < 0),
     runner:recv_eot(P1).
 
+-define(EI_DIST_LOW, 5).
+-define(EI_DIST_HIGH, 6).
 
 %% Check send with timeouts.
 ei_send_tmo(Config) when is_list(Config) ->
@@ -138,11 +140,15 @@ do_one_send(Config,From,CNode) ->
 
 ei_send_failure_tmo(Config) when is_list(Config) ->
     register(ei_send_tmo_1,self()),
-    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),
+    [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)],
     ok.
 
-do_one_send_failure(Config,From,FakeName,CName) ->
+do_one_send_failure(Config,From,FakeName,CName, OurVer) ->
     {_,Host} = split(node()),
     OurName = join(FakeName,Host),
     Node = join(CName,Host),
@@ -152,7 +158,7 @@ do_one_send_failure(Config,From,FakeName,CName) ->
                   Else ->
                       exit(Else)
               end,
-    EpmdSocket = register(OurName, LSocket, 1, 5),
+    EpmdSocket = epmd_register(OurName, LSocket, OurVer),
     P3 = runner:start(Config, ?send_tmo),
     Cookie = kaksmula_som_ingen_bryr_sig_om,
     runner:send_term(P3,{CName,
@@ -165,10 +171,10 @@ do_one_send_failure(Config,From,FakeName,CName) ->
                   Else2 ->
                       exit(Else2)
               end,
-    {hidden,Node,5} = recv_name(SocketB),  % See 1)
+    {hidden,Node} = recv_name(SocketB, OurVer),  % See 1)
     send_status(SocketB, ok),
     MyChallengeB = gen_challenge(),
-    send_challenge(SocketB, OurName, MyChallengeB, 5),
+    send_challenge(SocketB, OurName, MyChallengeB, OurVer),
     HisChallengeB = recv_challenge_reply(SocketB,
                                          MyChallengeB,
                                          Cookie),
@@ -214,6 +220,15 @@ 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].
+
+do_ei_connect_tmo(Config, OurVer, OurEpmdVer) ->
     P2 = runner:start(Config, ?connect_tmo),
     runner:send_term(P2,{c_nod_connect_tmo_2,
                          erlang:get_cookie(),
@@ -232,7 +247,7 @@ ei_connect_tmo(Config) when is_list(Config) ->
                   Else ->
                       exit(Else)
               end,
-    EpmdSocket = register(OurName, LSocket, 1, 5),
+    EpmdSocket = epmd_register(OurName, LSocket, OurEpmdVer),
     P3 = runner:start(Config, ?connect_tmo),
     Cookie = kaksmula_som_ingen_bryr_sig_om,
     runner:send_term(P3,{c_nod_connect_tmo_3,
@@ -245,10 +260,11 @@ ei_connect_tmo(Config) when is_list(Config) ->
                   Else2 ->
                       exit(Else2)
               end,
-    {hidden,Node,5} = recv_name(SocketB),  % See 1)
+    {hidden,Node} = recv_name(SocketB, OurEpmdVer),  % See 1)
     send_status(SocketB, ok),
     MyChallengeB = gen_challenge(),
-    send_challenge(SocketB, OurName, MyChallengeB, 5),
+    send_challenge(SocketB, OurName, MyChallengeB, OurVer),
+    recv_complement(SocketB, OurVer, OurEpmdVer),
     _HisChallengeB = recv_challenge_reply(SocketB,
                                           MyChallengeB,
                                           Cookie),
@@ -261,8 +277,17 @@ ei_connect_tmo(Config) when is_list(Config) ->
 
 %% Check accept with timeouts.
 ei_accept_tmo(Config) when is_list(Config) ->
-    %%dbg:tracer(),
-    %%dbg:p(self()),
+    [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) ->
     P = runner:start(Config, ?accept_tmo),
     runner:send_term(P,{c_nod_som_ingen_kontaktar_1,
                         kaksmula_som_ingen_bryr_sig_om,
@@ -288,13 +313,13 @@ ei_accept_tmo(Config) when is_list(Config) ->
     {NA,NB} = split(CNode2),
     {_,Host} = split(node()),
     OurName = join(ccc,Host),
-    {port,PortNo,_} = erl_epmd:port_please(NA,NB),
+    {port,PortNo,?EI_DIST_HIGH} = erl_epmd:port_please(NA,NB),
     {ok, SocketA} = gen_tcp:connect(atom_to_list(NB),PortNo,
                                     [{active,false},
                                      {packet,2}]),
-    send_name(SocketA,OurName,5),
+    send_name(SocketA,OurName,OurVer,AssumedVer),
     ok = recv_status(SocketA),
-    {hidden,_Node,5,HisChallengeA} = recv_challenge(SocketA), % See 1)
+    {hidden,_Node,HisChallengeA} = recv_challenge(SocketA,OurVer), % See 1)
     _OurChallengeA = gen_challenge(),
     _OurDigestA = gen_digest(HisChallengeA, erlang:get_cookie()),
     %% Dont do the last two steps of the connection setup...
@@ -340,6 +365,7 @@ make_and_check_dummy() ->
 -define(DFLAG_EXTENDED_PIDS_PORTS,16#100).
 -define(DFLAG_NEW_FLOATS,16#800).
 -define(DFLAG_DIST_MONITOR,8).
+-define(DFLAG_HANDSHAKE_23,16#1000000).
 
 %% From R9 and forward extended references is compulsory
 %% From 14 and forward new float is compulsory
@@ -403,31 +429,61 @@ recv_status(Socket) ->
             exit(Bad)
     end.
 
-send_challenge(Socket, Node, Challenge, Version) ->
-    send_challenge(Socket, Node, Challenge, Version, ?COMPULSORY_DFLAGS).
-send_challenge(Socket, Node, Challenge, Version, Flags) ->
-    {ok, {{_Ip1,_Ip2,_Ip3,_Ip4}, _}} = inet:sockname(Socket),
-    ?to_port(Socket, [$n,?int16(Version),?int32(Flags),
-                      ?int32(Challenge), atom_to_list(Node)]).
-
-recv_challenge(Socket) ->
+send_challenge(Socket, Node, Challenge, OurVer) ->
+    send_challenge(Socket, Node, Challenge, OurVer, ?COMPULSORY_DFLAGS).
+
+send_challenge(Socket, Node, Challenge, OurVer, Flags) ->
+    if OurVer =:= 5 ->
+            ?to_port(Socket, [$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, [$N,
+                              <<(Flags bor ?DFLAG_HANDSHAKE_23):64,
+                                Challenge:32,
+                                Creation:32,
+                                NameLen:16>>,
+                              NodeName])
+    end.       
+
+recv_challenge(Socket, OurVer) ->
     case gen_tcp:recv(Socket, 0) of
         {ok,[$n,V1,V0,Fl1,Fl2,Fl3,Fl4,CA3,CA2,CA1,CA0 | Ns]} ->
+            5 = OurVer,
             Flags = ?u32(Fl1,Fl2,Fl3,Fl4),
-            Type = case Flags band ?DFLAG_PUBLISHED of
-                       0 ->
-                           hidden;
-                       _ ->
-                           normal
-                   end,
+            Type = flags_to_type(Flags),
             Node =list_to_atom(Ns),
-            Version = ?u16(V1,V0),
+            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>>,
+            Type = flags_to_type(Flags),
+            NameLen = ?u16(NL1,NL0),
+            {NodeName,_} = lists:split(NameLen, Rest),
+            Node = list_to_atom(NodeName),
             Challenge = ?u32(CA3,CA2,CA1,CA0),
-            {Type,Node,Version,Challenge};
+            %%Creation = ?u32(Cr3,Cr2,Cr1,Cr0),
+            %%true = (Creation =/= 0),
+            {Type,Node,Challenge};
+
         _ ->
             ?shutdown(no_node)
     end.
 
+flags_to_type(Flags) ->
+    case Flags band ?DFLAG_PUBLISHED of
+        0 ->
+            hidden;
+        _ ->
+            normal
+    end.
+
 %send_challenge_reply(Socket, Challenge, Digest) ->
 %    ?to_port(Socket, [$r,?int32(Challenge),Digest]).
 
@@ -441,8 +497,8 @@ recv_challenge_reply(Socket, ChallengeA, Cookie) ->
                true ->
                    ?shutdown(bad_challenge_reply)
             end;
-        _ ->
-            ?shutdown(no_node)
+        Other ->
+            ?shutdown({recv_challenge_reply,Other})
     end.
 
 send_challenge_ack(Socket, Digest) ->
@@ -461,37 +517,53 @@ send_challenge_ack(Socket, Digest) ->
 %            ?shutdown(bad_challenge_ack)
 %    end.
 
-send_name(Socket, MyNode0, Version) ->
-    send_name(Socket, MyNode0, Version, ?COMPULSORY_DFLAGS).
-send_name(Socket, MyNode0, Version, Flags) ->
-    MyNode = atom_to_list(MyNode0),
-    ?to_port(Socket, [$n,?int16(Version),?int32(Flags)] ++ 
-             MyNode).
+send_name(Socket, MyNode, OurVer, AssumedVer) ->
+    Flags = ?COMPULSORY_DFLAGS bor (case OurVer of
+                                        5 -> 0;
+                                        6 -> ?DFLAG_HANDSHAKE_23
+                                    end),
+    send_name(Socket, MyNode, OurVer, AssumedVer, Flags).
+
+send_name(Socket, MyNode, OurVer, AssumedVer, Flags) ->
+    NodeName = atom_to_binary(MyNode, latin1),
+    if AssumedVer =:= 5 ->
+            ?to_port(Socket, [$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 is common for both old and new handshake.
-%%
-recv_name(Socket) ->
+recv_name(Socket, OurEpmdVer) ->
     case gen_tcp:recv(Socket, 0) of
-        {ok,Data} ->
-            get_name(Data);
+        {ok,[$n, V1,V0, F3,F2,F1,F0 | OtherNode]} ->
+            5 = OurEpmdVer,
+            5 = ?u16(V1,V0),
+            Type = flags_to_type(?u32(F3,F2,F1,F0)),
+            {Type, list_to_atom(OtherNode)};
+        {ok,[$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>>,
+            Type = flags_to_type(Flags),
+            {Type, list_to_atom(OtherNode)};
         Res ->
             ?shutdown({no_node,Res})
     end.
 
-get_name([$m,VersionA,VersionB,_Ip1,_Ip2,_Ip3,_Ip4|OtherNode]) ->
-    {normal, list_to_atom(OtherNode), ?u16(VersionA,VersionB)};
-get_name([$h,VersionA,VersionB,_Ip1,_Ip2,_Ip3,_Ip4|OtherNode]) ->
-    {hidden, list_to_atom(OtherNode), ?u16(VersionA,VersionB)};
-get_name([$n,VersionA, VersionB, Flag1, Flag2, Flag3, Flag4 | OtherNode]) ->
-    Type = case ?u32(Flag1, Flag2, Flag3, Flag4) band ?DFLAG_PUBLISHED of
-               0 -> hidden;
-               _ -> normal
-           end,
-    {Type, list_to_atom(OtherNode), 
-     ?u16(VersionA,VersionB)};
-get_name(Data) ->
-    ?shutdown(Data).
+recv_complement(Socket, OurVer, 5) when OurVer > 5 ->
+    case gen_tcp:recv(Socket, 0) of
+        {ok,[$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
@@ -536,13 +608,10 @@ wait_for_reg_reply(Socket, SoFar) ->
     receive
         {tcp, Socket, Data0} ->
             case SoFar ++ Data0 of
-                [$y, Result, A, B] ->
-                    case Result of
-                        0 ->
-                            {alive, Socket, ?u16(A, B)};
-                        _ ->
-                            {error, duplicate_name}
-                    end;
+                [$y, 0, Cr1,Cr0] ->
+                    {alive, Socket, ?u16(Cr1,Cr0)};
+                [$v, 0, Cr3,Cr2,Cr1,Cr0] ->
+                    {alive, Socket, ?u32(Cr3,Cr2,Cr1,Cr0)};
                 Data when length(Data) < 4 ->
                     wait_for_reg_reply(Socket, Data);
                 Garbage ->
@@ -556,9 +625,9 @@ wait_for_reg_reply(Socket, SoFar) ->
     end.
 
 
-register(NodeName, ListenSocket, VLow, VHigh) ->
+epmd_register(NodeName, ListenSocket, OurVer) ->
     {ok,{_,TcpPort}} = inet:sockname(ListenSocket),
-    case do_register_node(NodeName, TcpPort, VLow, VHigh) of
+    case do_register_node(NodeName, TcpPort, ?EI_DIST_LOW, OurVer) of
         {alive, Socket, _Creation} ->
             Socket;
         Other ->