fixup! gnrc_sixlowpan_frag_sfr: provide CongURE support

RIOT-OS · Mar 19, 2021 · 208aeea · 208aeea
1 parent d48cc11
commit 208aeea
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Showing 2 changed files with 48 additions and 3 deletions.
diff --git a/sys/include/net/gnrc/sixlowpan/frag/sfr/congure.h b/sys/include/net/gnrc/sixlowpan/frag/sfr/congure.h
@@ -136,6 +136,9 @@ static inline void gnrc_sixlowpan_frag_sfr_congure_snd_setup(gnrc_sixlowpan_frag
         fb->sfr.congure = gnrc_sixlowpan_frag_sfr_congure_snd_get();
         assert(fb->sfr.congure);
         gnrc_sixlowpan_frag_sfr_congure_snd_init(fb);
+        if (fb->sfr.congure->cwnd > CONFIG_GNRC_SIXLOWPAN_SFR_MAX_WIN_SIZE) {
+            fb->sfr.congure->cwnd = CONFIG_GNRC_SIXLOWPAN_SFR_MAX_WIN_SIZE;
+        }
     }
 #else
     (void)fb;
@@ -372,6 +375,9 @@ static inline void gnrc_sixlowpan_frag_sfr_congure_snd_report_frag_acked(
     congure_snd_t *c = fb->sfr.congure;
 
     c->driver->report_msg_acked(c, frag, ack);
+    if (c->cwnd > CONFIG_GNRC_SIXLOWPAN_SFR_MAX_WIN_SIZE) {
+        c->cwnd = CONFIG_GNRC_SIXLOWPAN_SFR_MAX_WIN_SIZE;
+    }
 #else
     (void)fb;
     (void)frag;

diff --git a/sys/net/gnrc/network_layer/sixlowpan/frag/sfr/gnrc_sixlowpan_frag_sfr.c b/sys/net/gnrc/network_layer/sixlowpan/frag/sfr/gnrc_sixlowpan_frag_sfr.c
@@ -175,6 +175,15 @@ static bool _send_abort_frag(gnrc_pktsnip_t *pkt,
                              gnrc_sixlowpan_frag_fb_t *fbuf,
                              bool req_ack, unsigned page);
 
+/**
+ * @brief   Adapts currently sent number of fragments to current window size
+ *
+ * Balances `fbuf->sfr.window` with `fbuf->sfr.congure->cwnd`
+ *
+ * @param[in] fbuf          Fragmentation buffer to adapt window for
+ */
+static void _shrink_window(gnrc_sixlowpan_frag_fb_t *fbuf);
+
 /**
  * @brief   Re-send a fragment
  *
@@ -467,8 +476,7 @@ static int _report_non_ack_req_window_sent(clist_node_t *node, void *fbuf_ptr)
 void gnrc_sixlowpan_frag_sfr_arq_timeout(gnrc_sixlowpan_frag_fb_t *fbuf)
 {
     uint32_t now = xtimer_now_usec() / US_PER_MS;
-    _frag_desc_t * const head = (_frag_desc_t *)fbuf->sfr.window.next;
-    _frag_desc_t *frag_desc = head;
+    _frag_desc_t *frag_desc = (_frag_desc_t *)fbuf->sfr.window.next;
     uint32_t next_arq_offset = fbuf->sfr.arq_timeout;
     bool reschedule_arq_timeout = false;
     int error_no = ETIMEDOUT;   /* assume time out for fbuf->pkt */
@@ -479,9 +487,14 @@ void gnrc_sixlowpan_frag_sfr_arq_timeout(gnrc_sixlowpan_frag_fb_t *fbuf)
         /* time goes by ;-) */
         now -= (fbuf->sfr.arq_timeout * US_PER_MS) + 1;
     }
+    if (IS_USED(MODULE_GNRC_SIXLOWPAN_FRAG_SFR_CONGURE) && frag_desc) {
+        gnrc_sixlowpan_frag_sfr_congure_snd_report_frags_timeout(fbuf);
+        _shrink_window(fbuf);
+        frag_desc = (_frag_desc_t *)fbuf->sfr.window.next;
+    }
+    _frag_desc_t * const head = frag_desc;
     /* copying clist_foreach because we can't work just in function context */
     if (frag_desc) {
-        gnrc_sixlowpan_frag_sfr_congure_snd_report_frags_timeout(fbuf);
         do {
             uint32_t diff;
 
@@ -1249,6 +1262,7 @@ static void _check_failed_frags(sixlowpan_sfr_ack_t *ack,
             (congure_snd_msg_t *)&not_received
         );
         fbuf->sfr.window = not_received;
+        _shrink_window(fbuf);
         assert(fbuf->sfr.frags_sent == clist_count(&fbuf->sfr.window));
         /* use _resend_failed_frag here instead of loop above, so
          * _resend_frag can know if the fragment is the last in the window by
@@ -1429,6 +1443,31 @@ static bool _send_abort_frag(gnrc_pktsnip_t *pkt,
     return false;
 }
 
+static void _shrink_window(gnrc_sixlowpan_frag_fb_t *fbuf)
+{
+    if (!IS_USED(MODULE_GNRC_SIXLOWPAN_FRAG_SFR_CONGURE)) {
+        /* window does not shrink without congure */
+        return;
+    }
+    if (!gnrc_sixlowpan_frag_sfr_congure_snd_in_cwnd(fbuf)) {
+        clist_node_t new_window = { .next = NULL };
+        _frag_desc_t *last;
+
+        fbuf->sfr.frags_sent = 0;
+        while (gnrc_sixlowpan_frag_sfr_congure_snd_in_cwnd(fbuf)) {
+            clist_rpush(&new_window, clist_lpop(&fbuf->sfr.window));
+            fbuf->sfr.frags_sent++;
+        }
+        for (clist_node_t *node = clist_lpop(&fbuf->sfr.window);
+             node != NULL; node = clist_lpop(&fbuf->sfr.window)) {
+            clist_rpush(&_frag_descs_free, node);
+        }
+        fbuf->sfr.window.next = new_window.next;
+        last = (_frag_desc_t *)clist_rpeek(&fbuf->sfr.window);
+        fbuf->offset = last->offset + _frag_size(last);
+    }
+}
+
 static int _resend_frag(clist_node_t *node, void *fbuf_ptr)
 {
     _frag_desc_t *frag_desc = (_frag_desc_t *)node;