From 5b5f109824b08619b9167cc82a8b56072a1ed477 Mon Sep 17 00:00:00 2001
From: defanor <defanor@uberspace.net>
Date: Mon, 30 Nov 2020 17:56:44 +0300
Subject: Reconnect on "reset" and "system-shutdown" stream errors

---
 README       |  6 +++---
 src/rexmpp.c | 25 +++++++++++++++++++------
 src/rexmpp.h |  4 +++-
 3 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/README b/README
index 61e39e6..5b4d422 100644
--- a/README
+++ b/README
@@ -23,8 +23,8 @@ A rough roadmap:
 
 - Basic protocol:
 
-[+] XMPP core (RFC 6120). A prototype is mostly ready, though it can
-    use more of error handling and refinement.
+[+] XMPP core (RFC 6120). Mostly ready, though would be nice to
+    review and refactor.
 
 
 - Reliable and predictable message delivery:
@@ -38,7 +38,7 @@ A rough roadmap:
 
 [+] "Happy Eyeballs" (RFC 8305).
 [+] XEP-0368 v1.1: SRV records for XMPP over TLS.
-[+] SOCKS5 (RFC 1928) support. Implemented, though can be improved.
+[+] SOCKS5 (RFC 1928) support. Implemented, though no authentication.
 [+] XEP-0199 v2.0: XMPP Ping.
 [.] Certificate verification using DANE (experimental).
 
diff --git a/src/rexmpp.c b/src/rexmpp.c
index 2594089..0857209 100644
--- a/src/rexmpp.c
+++ b/src/rexmpp.c
@@ -1091,9 +1091,12 @@ rexmpp_err_t rexmpp_recv (rexmpp_t *s) {
       }
       rexmpp_log(s, LOG_INFO, "TCP disconnected");
       rexmpp_cleanup(s);
-      s->tcp_state = REXMPP_TCP_CLOSED;
-      if (s->stream_state == REXMPP_STREAM_READY) {
+      if (s->stream_state == REXMPP_STREAM_READY ||
+          s->stream_state == REXMPP_STREAM_ERROR_RECONNECT) {
+        s->tcp_state = REXMPP_TCP_NONE;
         rexmpp_schedule_reconnect(s);
+      } else {
+        s->tcp_state = REXMPP_TCP_CLOSED;
       }
     } else {
       if (s->tls_state == REXMPP_TLS_ACTIVE) {
@@ -2054,9 +2057,18 @@ rexmpp_err_t rexmpp_process_element (rexmpp_t *s, xmlNodePtr elem) {
   /* Stream errors, https://tools.ietf.org/html/rfc6120#section-4.9 */
   if (rexmpp_xml_match(elem, "http://etherx.jabber.org/streams",
                        "error")) {
-    rexmpp_log(s, LOG_ERR, "stream error");
-    s->stream_state = REXMPP_STREAM_ERROR;
-    return REXMPP_E_STREAM;
+    if (rexmpp_xml_find_child(elem, "urn:ietf:params:xml:ns:xmpp-streams",
+                              "reset") != NULL ||
+        rexmpp_xml_find_child(elem, "urn:ietf:params:xml:ns:xmpp-streams",
+                              "system-shutdown") != NULL) {
+      rexmpp_log(s, LOG_WARNING, "Server reset or shutdown.");
+      s->stream_state = REXMPP_STREAM_ERROR_RECONNECT;
+      return REXMPP_E_AGAIN;
+    } else {
+      rexmpp_log(s, LOG_ERR, "Stream error");
+      s->stream_state = REXMPP_STREAM_ERROR;
+      return REXMPP_E_STREAM;
+    }
   }
 
   /* STARTTLS negotiation,
@@ -2503,7 +2515,8 @@ rexmpp_err_t rexmpp_run (rexmpp_t *s, fd_set *read_fds, fd_set *write_fds) {
     }
   }
 
-  if (s->tcp_state == REXMPP_TCP_CLOSED) {
+  if (s->tcp_state == REXMPP_TCP_CLOSED &&
+      s->stream_state != REXMPP_STREAM_ERROR_RECONNECT) {
     rexmpp_console_on_run(s, REXMPP_SUCCESS);
     return REXMPP_SUCCESS;
   } else {
diff --git a/src/rexmpp.h b/src/rexmpp.h
index bd6f8cb..2f21fce 100644
--- a/src/rexmpp.h
+++ b/src/rexmpp.h
@@ -112,7 +112,9 @@ enum stream_st {
   /** The server-to-client stream is closed. */
   REXMPP_STREAM_CLOSED,
   /** A stream error was detected in the server-to-client stream. */
-  REXMPP_STREAM_ERROR
+  REXMPP_STREAM_ERROR,
+  /** A stream error that should be fixed by a reconnect. */
+  REXMPP_STREAM_ERROR_RECONNECT
 };
 
 /** @brief TLS state */
-- 
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