routing: improve debug logging

Use standard logging (FIB_XX_LOG) across nhg code instead of using
 old-style DPRINTFs.
 Add debug object printer for nhgs (`nhgrp_print_buf`).

Example:

```
Jun 19 20:17:09 devel2 kernel: [nhgrp] inet.0 nhgrp_ctl_alloc_default: multipath init done
Jun 19 20:17:09 devel2 kernel: [nhg_ctl] inet.0 alloc_nhgrp: num_nhops: 2, compiled_nhop: 2

Jun 19 20:17:26 devel2 kernel: [nhg_ctl] inet.0 alloc_nhgrp: num_nhops: 3, compiled_nhop: 3
Jun 19 20:17:26 devel2 kernel: [nhg_ctl] inet.0 destroy_nhgrp: destroying nhg#0/sz=2:[#6:1,#5:1]
```

Differential Revision: https://reviews.freebsd.org/D35525
MFC after: 2 weeks

Author: AlexanderChernikov

sys/net/route/nhgrp.c

@@ -60,6 +60,11 @@
 #include <net/route/nhop_var.h>
 #include <net/route/nhgrp_var.h>
 
+#define	DEBUG_MOD_NAME	nhgrp
+#define	DEBUG_MAX_LEVEL	LOG_DEBUG
+#include <net/route/route_debug.h>
+_DECLARE_DEBUG(LOG_INFO);
+
 /*
  * This file contains data structures management logic for the nexthop
  * groups ("nhgrp") route subsystem.
@@ -163,7 +168,7 @@ link_nhgrp(struct nh_control *ctl, struct nhgrp_priv *grp_priv)
 
 	if (bitmask_alloc_idx(&ctl->nh_idx_head, &idx) != 0) {
 		NHOPS_WUNLOCK(ctl);
-		DPRINTF("Unable to allocate mpath index");
+		FIB_RH_LOG(LOG_INFO, ctl->ctl_rh, "Unable to allocate nhg index");
 		consider_resize(ctl, new_num_buckets, new_num_items);
 		return (0);
 	}
@@ -190,7 +195,7 @@ unlink_nhgrp(struct nh_control *ctl, struct nhgrp_priv *key)
 	CHT_SLIST_REMOVE(&ctl->gr_head, mpath, key, nhg_priv_ret);
 
 	if (nhg_priv_ret == NULL) {
-		DPRINTF("Unable to find nhop group!");
+		FIB_RH_LOG(LOG_DEBUG, ctl->ctl_rh, "Unable to find nhg");
 		NHOPS_WUNLOCK(ctl);
 		return (NULL);
 	}
@@ -233,7 +238,8 @@ consider_resize(struct nh_control *ctl, uint32_t new_gr_bucket, uint32_t new_idx
 		return;
 	}
 
-	DPRINTF("mp: going to resize: gr:[ptr:%p sz:%u] idx:[ptr:%p sz:%u]",
+	FIB_RH_LOG(LOG_DEBUG, ctl->ctl_rh,
+	    "going to resize nhg hash: [ptr:%p sz:%u] idx:[ptr:%p sz:%u]",
 	    gr_ptr, new_gr_bucket, gr_idx_ptr, new_idx_items);
 
 	old_idx_ptr = NULL;
@@ -271,7 +277,7 @@ nhgrp_ctl_alloc_default(struct nh_control *ctl, int malloc_flags)
 	cht_ptr = malloc(alloc_size, M_NHOP, malloc_flags);
 
 	if (cht_ptr == NULL) {
-		DPRINTF("mpath init failed");
+		FIB_RH_LOG(LOG_WARNING, ctl->ctl_rh, "multipath init failed");
 		return (false);
 	}
 
@@ -287,8 +293,7 @@ nhgrp_ctl_alloc_default(struct nh_control *ctl, int malloc_flags)
 		free(cht_ptr, M_NHOP);
 	}
 
-	DPRINTF("mpath init done for fib/af %d/%d", ctl->rh->rib_fibnum,
-	    ctl->rh->rib_family);
+	FIB_RH_LOG(LOG_DEBUG, ctl->ctl_rh, "multipath init done");
 
 	return (true);
 }
@@ -320,7 +325,11 @@ nhgrp_ctl_unlink_all(struct nh_control *ctl)
 	NHOPS_WLOCK_ASSERT(ctl);
 
 	CHT_SLIST_FOREACH(&ctl->gr_head, mpath, nhg_priv) {
-		DPRINTF("Marking nhgrp %u unlinked", nhg_priv->nhg_idx);
+#if DEBUG_MAX_LEVEL >= LOG_DEBUG
+		char nhgbuf[NHOP_PRINT_BUFSIZE];
+		FIB_RH_LOG(LOG_DEBUG, ctl->ctl_rh, "marking %s unlinked",
+		    nhgrp_print_buf(nhg_priv->nhg, nhgbuf, sizeof(nhgbuf)));
+#endif
 		refcount_release(&nhg_priv->nhg_linked);
 	} CHT_SLIST_FOREACH_END;
 }

sys/net/route/nhgrp_ctl.c

@@ -58,6 +58,11 @@
 #include <net/route/nhop_var.h>
 #include <net/route/nhgrp_var.h>
 
+#define	DEBUG_MOD_NAME	nhgrp_ctl
+#define	DEBUG_MAX_LEVEL	LOG_DEBUG
+#include <net/route/route_debug.h>
+_DECLARE_DEBUG(LOG_INFO);
+
 /*
  * This file contains the supporting functions for creating multipath groups
  *  and compiling their dataplane parts.
@@ -222,7 +227,8 @@ compile_nhgrp(struct nhgrp_priv *dst_priv, const struct weightened_nhop *x,
 	for (i = 0; i < dst_priv->nhg_nh_count; i++)
 		remaining_sum += x[i].weight;
 	remaining_slots = num_slots;
-	DPRINTF("O: %u/%u", (uint32_t)remaining_sum, remaining_slots);
+	FIB_NH_LOG(LOG_DEBUG3, x[0].nh, "sum: %lu, slots: %d",
+	    remaining_sum, remaining_slots);
 	for (i = 0; i < dst_priv->nhg_nh_count; i++) {
 		/* Calculate number of slots for the current nexthop */
 		if (remaining_sum > 0) {
@@ -234,9 +240,9 @@ compile_nhgrp(struct nhgrp_priv *dst_priv, const struct weightened_nhop *x,
 		remaining_sum -= x[i].weight;
 		remaining_slots -= nh_slots;
 
-		DPRINTF(" OO[%d]: %u/%u curr=%d slot_idx=%d", i,
-		    (uint32_t)remaining_sum, remaining_slots,
-		    (int)nh_slots, slot_idx);
+		FIB_NH_LOG(LOG_DEBUG3, x[0].nh,
+		    " rem_sum: %lu, rem_slots: %d nh_slots: %d, slot_idx: %d",
+		    remaining_sum, remaining_slots, (int)nh_slots, slot_idx);
 
 		KASSERT((slot_idx + nh_slots <= num_slots),
 		    ("index overflow during nhg compilation"));
@@ -267,12 +273,14 @@ alloc_nhgrp(struct weightened_nhop *wn, int num_nhops)
 	size_t sz = get_nhgrp_alloc_size(nhgrp_size, num_nhops);
 	nhg = malloc(sz, M_NHOP, M_NOWAIT | M_ZERO);
 	if (nhg == NULL) {
+		FIB_NH_LOG(LOG_INFO, wn[0].nh,
+		    "unable to allocate group with num_nhops %d (compiled %u)",
+		    num_nhops, nhgrp_size);
 		return (NULL);
 	}
 
 	/* Has to be the first to make NHGRP_PRIV() work */
 	nhg->nhg_size = nhgrp_size;
-	DPRINTF("new mpath group: num_nhops: %u", (uint32_t)nhgrp_size);
 	nhg->nhg_flags = MPF_MULTIPATH;
 
 	nhg_priv = NHGRP_PRIV(nhg);
@@ -286,6 +294,9 @@ alloc_nhgrp(struct weightened_nhop *wn, int num_nhops)
 	memcpy(&nhg_priv->nhg_nh_weights[0], wn,
 	  num_nhops * sizeof(struct weightened_nhop));
 
+	FIB_NH_LOG(LOG_DEBUG, wn[0].nh, "num_nhops: %d, compiled_nhop: %u",
+	    num_nhops, nhgrp_size);
+
 	compile_nhgrp(nhg_priv, wn, nhg->nhg_size);
 
 	return (nhg_priv);
@@ -345,7 +356,8 @@ nhgrp_free(struct nhgrp_object *nhg)
 		ctl = nhg_priv->nh_control;
 		if (unlink_nhgrp(ctl, nhg_priv) == NULL) {
 			/* Do not try to reclaim */
-			DPRINTF("Failed to unlink nexhop group %p", nhg_priv);
+			RT_LOG(LOG_INFO, "Failed to unlink nexhop group %p",
+			    nhg_priv);
 			NET_EPOCH_EXIT(et);
 			return;
 		}
@@ -371,13 +383,16 @@ destroy_nhgrp(struct nhgrp_priv *nhg_priv)
 {
 
 	KASSERT((nhg_priv->nhg_refcount == 0), ("nhg_refcount != 0"));
-
-	DPRINTF("DEL MPATH %p", nhg_priv);
-
 	KASSERT((nhg_priv->nhg_idx == 0), ("gr_idx != 0"));
 
-	free_nhgrp_nhops(nhg_priv);
+#if DEBUG_MAX_LEVEL >= LOG_DEBUG
+	char nhgbuf[NHOP_PRINT_BUFSIZE];
+	FIB_NH_LOG(LOG_DEBUG, nhg_priv->nhg_nh_weights[0].nh,
+	    "destroying %s", nhgrp_print_buf(nhg_priv->nhg,
+	    nhgbuf, sizeof(nhgbuf)));
+#endif
 
+	free_nhgrp_nhops(nhg_priv);
 	destroy_nhgrp_int(nhg_priv);
 }
 
@@ -695,6 +710,37 @@ nhgrp_get_nhops(struct nhgrp_object *nhg, uint32_t *pnum_nhops)
 	return (nhg_priv->nhg_nh_weights);
 }
 
+/*
+ * Prints nexhop group @nhg data in the provided @buf.
+ * Example: nhg#33/sz=3:[#1:100,#2:100,#3:100]
+ * Example: nhg#33/sz=5:[#1:100,#2:100,..]
+ */
+char *
+nhgrp_print_buf(const struct nhgrp_object *nhg, char *buf, size_t bufsize)
+{
+	const struct nhgrp_priv *nhg_priv = NHGRP_PRIV_CONST(nhg);
+
+	int off = snprintf(buf, bufsize, "nhg#%u/sz=%u:[", nhg_priv->nhg_idx,
+	    nhg_priv->nhg_nh_count);
+
+	for (int i = 0; i < nhg_priv->nhg_nh_count; i++) {
+		const struct weightened_nhop *wn = &nhg_priv->nhg_nh_weights[i];
+		int len = snprintf(&buf[off], bufsize - off, "#%u:%u,",
+		    wn->nh->nh_priv->nh_idx, wn->weight);
+		if (len + off + 3 >= bufsize) {
+			int len = snprintf(&buf[off], bufsize - off, "...");
+			off += len;
+			break;
+		}
+		off += len;
+	}
+	if (off > 0)
+		off--; // remove last ","
+	if (off + 1 < bufsize)
+		snprintf(&buf[off], bufsize - off, "]");
+	return buf;
+}
+
 __noinline static int
 dump_nhgrp_entry(struct rib_head *rh, const struct nhgrp_priv *nhg_priv,
     char *buffer, size_t buffer_size, struct sysctl_req *w)

sys/net/route/nhop_ctl.c

@@ -584,7 +584,7 @@ finalize_nhop(struct nh_control *ctl, struct rt_addrinfo *info,
 		 *  the epoch end, as nexthop is not used
 		 *  and return.
 		 */
-		char nhbuf[48];
+		char nhbuf[NHOP_PRINT_BUFSIZE];
 		FIB_NH_LOG(LOG_WARNING, nh, "failed to link %s",
 		    nhop_print_buf(nh, nhbuf, sizeof(nhbuf)));
 		destroy_nhop(nh_priv);
@@ -593,7 +593,7 @@ finalize_nhop(struct nh_control *ctl, struct rt_addrinfo *info,
 	}
 
 #if DEBUG_MAX_LEVEL >= LOG_DEBUG
-	char nhbuf[48];
+	char nhbuf[NHOP_PRINT_BUFSIZE];
 	FIB_NH_LOG(LOG_DEBUG, nh, "finalized: %s", nhop_print_buf(nh, nhbuf, sizeof(nhbuf)));
 #endif
 
@@ -655,7 +655,7 @@ nhop_free(struct nhop_object *nh)
 		return;
 
 #if DEBUG_MAX_LEVEL >= LOG_DEBUG
-	char nhbuf[48];
+	char nhbuf[NHOP_PRINT_BUFSIZE];
 	FIB_NH_LOG(LOG_DEBUG, nh, "deleting %s", nhop_print_buf(nh, nhbuf, sizeof(nhbuf)));
 #endif
 
@@ -683,7 +683,7 @@ nhop_free(struct nhop_object *nh)
 		ctl = nh_priv->nh_control;
 		if (unlink_nhop(ctl, nh_priv) == NULL) {
 			/* Do not try to reclaim */
-			char nhbuf[48];
+			char nhbuf[NHOP_PRINT_BUFSIZE];
 			FIB_NH_LOG(LOG_WARNING, nh, "failed to unlink %s",
 			    nhop_print_buf(nh, nhbuf, sizeof(nhbuf)));
 			NET_EPOCH_EXIT(et);
@@ -864,6 +864,17 @@ nhop_print_buf(const struct nhop_object *nh, char *buf, size_t bufsize)
 	return (buf);
 }
 
+char *
+nhop_print_buf_any(const struct nhop_object *nh, char *buf, size_t bufsize)
+{
+#ifdef ROUTE_MPATH
+	if (NH_IS_NHGRP(nh))
+		return (nhgrp_print_buf((const struct nhgrp_object *)nh, buf, bufsize));
+	else
+#endif
+		return (nhop_print_buf(nh, buf, bufsize));
+}
+
 /*
  * Dumps a single entry to sysctl buffer.
  *

sys/net/route/route_debug.h

@@ -76,6 +76,8 @@
 
 /* Same as FIB_LOG, but uses nhop to get fib and family */
 #define FIB_NH_LOG(_l, _nh, _fmt, ...)  FIB_LOG_##_l(_l, nhop_get_fibnum(_nh), nhop_get_upper_family(_nh), _fmt, ## __VA_ARGS__)
+/* Same as FIB_LOG, but uses rib_head to get fib and family */
+#define FIB_RH_LOG(_l, _rh, _fmt, ...)  FIB_LOG_##_l(_l, (_rh)->rib_fibnum, (_rh)->rib_family, _fmt, ## __VA_ARGS__)
 
 /*
  * Generic logging for routing subsystem
@@ -90,7 +92,7 @@
 /*
  * Wrapper logic to avoid compiling high levels of debugging messages for production systems.
  */
-#if DEBUG_MAX_LEVEL>=LOG_DEBUG2
+#if DEBUG_MAX_LEVEL>=LOG_DEBUG3
 #define	FIB_LOG_LOG_DEBUG3	_FIB_LOG
 #define	RT_LOG_LOG_DEBUG3	_RT_LOG
 #else
@@ -129,10 +131,14 @@
 
 /* Helpers for fancy-printing various objects */
 struct nhop_object;
+struct nhgrp_object;
 struct llentry;
 struct nhop_neigh;
 
+#define	NHOP_PRINT_BUFSIZE	48
 char *nhop_print_buf(const struct nhop_object *nh, char *buf, size_t bufsize);
+char *nhop_print_buf_any(const struct nhop_object *nh, char *buf, size_t bufsize);
+char *nhgrp_print_buf(const struct nhgrp_object *nhg, char *buf, size_t bufsize);
 char *llentry_print_buf(const struct llentry *lle, struct ifnet *ifp, int family, char *buf,
     size_t bufsize);
 char *llentry_print_buf_lltable(const struct llentry *lle, char *buf, size_t bufsize);