[DCCP]: Simplified conditions due to use of enum:8 states

This reaps the benefit of the earlier patch, which changed the type of
CCID 3 states to use enums, in that many conditions are now simplified
and the number of possible (unexpected) values is greatly reduced.

In a few instances, this also allowed to simplify pre-conditions; where
care has been taken to retain logical equivalence.

[DCCP]: Introduce a consistent BUG/WARN message scheme

This refines the existing set of DCCP messages so that
 * BUG(), BUG_ON(), WARN_ON() have meaningful DCCP-specific counterparts
 * DCCP_CRIT (for severe warnings) is not rate-limited
 * DCCP_WARN() is introduced as rate-limited wrapper

Using these allows a faster and cleaner transition to their original
counterparts once the code has matured into a full DCCP implementation.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

net/dccp/ackvec.c

@@ -461,9 +461,6 @@ int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
 	return 0;
 }
 
-static char dccp_ackvec_slab_msg[] __initdata =
-	KERN_CRIT "DCCP: Unable to create ack vectors slab caches\n";
-
 int __init dccp_ackvec_init(void)
 {
 	dccp_ackvec_slab = kmem_cache_create("dccp_ackvec",
@@ -485,7 +482,7 @@ int __init dccp_ackvec_init(void)
 	kmem_cache_destroy(dccp_ackvec_slab);
 	dccp_ackvec_slab = NULL;
 out_err:
-	printk(dccp_ackvec_slab_msg);
+	DCCP_CRIT("Unable to create Ack Vector slab cache");
 	return -ENOBUFS;
 }
 

net/dccp/ccids/ccid2.c

@@ -420,7 +420,7 @@ static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset,
 	return -1;
 
 out_invalid_option:
-	BUG_ON(1); /* should never happen... options were previously parsed ! */
+	DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
 	return -1;
 }
 

net/dccp/ccids/lib/loss_interval.c

@@ -13,7 +13,7 @@
 
 #include <linux/module.h>
 #include <net/sock.h>
-
+#include "../../dccp.h"
 #include "loss_interval.h"
 
 struct dccp_li_hist *dccp_li_hist_new(const char *name)
@@ -109,7 +109,7 @@ u32 dccp_li_hist_calc_i_mean(struct list_head *list)
 	i_tot = max(i_tot0, i_tot1);
 
 	if (!w_tot) {
-		LIMIT_NETDEBUG(KERN_WARNING "%s: w_tot = 0\n", __FUNCTION__);
+		DCCP_WARN("w_tot = 0\n");
 		return 1;
 	}
 
@@ -128,7 +128,7 @@ int dccp_li_hist_interval_new(struct dccp_li_hist *hist,
 		entry = dccp_li_hist_entry_new(hist, SLAB_ATOMIC);
 		if (entry == NULL) {
 			dccp_li_hist_purge(hist, list);
-			dump_stack();
+			DCCP_BUG("loss interval list entry is NULL");
 			return 0;
 		}
 		entry->dccplih_interval = ~0;

net/dccp/ccids/lib/tfrc_equation.c

@@ -13,9 +13,8 @@
  */
 
 #include <linux/module.h>
-
 #include <asm/div64.h>
-
+#include "../../dccp.h"
 #include "tfrc.h"
 
 #define TFRC_CALC_X_ARRSIZE 500
@@ -588,8 +587,10 @@ u32 tfrc_calc_x(u16 s, u32 R, u32 p)
 		/* p should be 0 unless there is a bug in my code */
 		index = 0;
 
-	if (R == 0)
+	if (R == 0) {
+		DCCP_WARN("RTT==0, setting to 1\n");
 		R = 1; /* RTT can't be zero or else divide by zero */
+	}
 
 	BUG_ON(index >= TFRC_CALC_X_ARRSIZE);
 

net/dccp/dccp.h

@@ -18,12 +18,17 @@
 #include <net/tcp.h>
 #include "ackvec.h"
 
-#define DCCP_CRIT(fmt, a...) LIMIT_NETDEBUG(KERN_CRIT fmt " at %s:%d/%s()\n",  \
- 					 ##a, __FILE__, __LINE__, __FUNCTION__)
-#define DCCP_BUG(fmt, a...)  do { DCCP_CRIT(fmt, ##a); dump_stack(); } while (0)
-#define DCCP_BUG_ON(cond)    do { if (unlikely((cond) == 0))                   \
-					DCCP_BUG("BUG: condition \"%s\" fails",\
-						 __stringify((cond)));	       \
+/*
+ * 	DCCP - specific warning and debugging macros.
+ */
+#define DCCP_WARN(fmt, a...) LIMIT_NETDEBUG(KERN_WARNING "%s: " fmt,       \
+						        __FUNCTION__, ##a)
+#define DCCP_CRIT(fmt, a...) printk(KERN_CRIT fmt " at %s:%d/%s()\n", ##a, \
+					 __FILE__, __LINE__, __FUNCTION__)
+#define DCCP_BUG(a...)       do { DCCP_CRIT("BUG: " a); dump_stack(); } while(0)
+#define DCCP_BUG_ON(cond)    do { if (unlikely((cond) != 0))		   \
+				     DCCP_BUG("\"%s\" holds (exception!)", \
+					      __stringify(cond));          \
 			     } while (0)
 
 #ifdef MODULE

net/dccp/feat.c

@@ -25,11 +25,11 @@ int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
 	dccp_feat_debug(type, feature, *val);
 
 	if (!dccp_feat_is_valid_type(type)) {
-		pr_info("option type %d invalid in negotiation\n", type);
+		DCCP_WARN("option type %d invalid in negotiation\n", type);
 		return 1;
 	}
 	if (!dccp_feat_is_valid_length(type, feature, len)) {
-		pr_info("invalid length %d\n", len);
+		DCCP_WARN("invalid length %d\n", len);
 		return 1;
 	}
 	/* XXX add further sanity checks */
@@ -169,7 +169,8 @@ static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt,
 			break;
 
 		default:
-			WARN_ON(1); /* XXX implement res */
+			DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat);
+			/* XXX implement res */
 			return -EFAULT;
 		}
 
@@ -328,7 +329,7 @@ static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,
 	switch (type) {
 	case DCCPO_CHANGE_L: opt->dccpop_type = DCCPO_CONFIRM_R; break;
 	case DCCPO_CHANGE_R: opt->dccpop_type = DCCPO_CONFIRM_L; break;
-	default: 	     pr_info("invalid type %d\n", type); return;
+	default: 	     DCCP_WARN("invalid type %d\n", type); return;
 
 	}
 	opt->dccpop_feat = feature;
@@ -426,7 +427,7 @@ int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
 	switch (type) {
 	case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break;
 	case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break;
-	default: 	      pr_info("invalid type %d\n", type);
+	default: 	      DCCP_WARN("invalid type %d\n", type);
 			      return 1;
 
 	}

net/dccp/input.c

@@ -128,21 +128,18 @@ static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
 		     DCCP_PKT_WITHOUT_ACK_SEQ))
 			dp->dccps_gar = DCCP_SKB_CB(skb)->dccpd_ack_seq;
 	} else {
-		LIMIT_NETDEBUG(KERN_WARNING "DCCP: Step 6 failed for %s packet, "
-					    "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
-					    "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
-					    "sending SYNC...\n",
-			       dccp_packet_name(dh->dccph_type),
-			       (unsigned long long) lswl,
-			       (unsigned long long)
-			       DCCP_SKB_CB(skb)->dccpd_seq,
-			       (unsigned long long) dp->dccps_swh,
-			       (DCCP_SKB_CB(skb)->dccpd_ack_seq ==
+		DCCP_WARN("DCCP: Step 6 failed for %s packet, "
+			  "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
+			  "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
+			  "sending SYNC...\n",  dccp_packet_name(dh->dccph_type),
+			  (unsigned long long) lswl,
+			  (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq,
+			  (unsigned long long) dp->dccps_swh,
+			  (DCCP_SKB_CB(skb)->dccpd_ack_seq ==
 			        DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" : "exists",
-			       (unsigned long long) lawl,
-			       (unsigned long long)
-			       DCCP_SKB_CB(skb)->dccpd_ack_seq,
-			       (unsigned long long) dp->dccps_awh);
+			  (unsigned long long) lawl,
+			  (unsigned long long) DCCP_SKB_CB(skb)->dccpd_ack_seq,
+			  (unsigned long long) dp->dccps_awh);
 		dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
 		return -1;
 	}

net/dccp/ipv4.c

@@ -747,7 +747,7 @@ int dccp_invalid_packet(struct sk_buff *skb)
 
 	/* If the packet is shorter than 12 bytes, drop packet and return */
 	if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
-		LIMIT_NETDEBUG(KERN_WARNING "DCCP: pskb_may_pull failed\n");
+		DCCP_WARN("pskb_may_pull failed\n");
 		return 1;
 	}
 
@@ -755,7 +755,7 @@ int dccp_invalid_packet(struct sk_buff *skb)
 
 	/* If P.type is not understood, drop packet and return */
 	if (dh->dccph_type >= DCCP_PKT_INVALID) {
-		LIMIT_NETDEBUG(KERN_WARNING "DCCP: invalid packet type\n");
+		DCCP_WARN("invalid packet type\n");
 		return 1;
 	}
 
@@ -763,16 +763,14 @@ int dccp_invalid_packet(struct sk_buff *skb)
 	 * If P.Data Offset is too small for packet type, drop packet and return
 	 */
 	if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
-		LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
-					    "too small\n", dh->dccph_doff);
+		DCCP_WARN("P.Data Offset(%u) too small\n", dh->dccph_doff);
 		return 1;
 	}
 	/*
 	 * If P.Data Offset is too too large for packet, drop packet and return
 	 */
 	if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
-		LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
-					    "too large\n", dh->dccph_doff);
+		DCCP_WARN("P.Data Offset(%u) too large\n", dh->dccph_doff);
 		return 1;
 	}
 
@@ -782,9 +780,8 @@ int dccp_invalid_packet(struct sk_buff *skb)
 	 */
 	if (dh->dccph_type >= DCCP_PKT_DATA    &&
 	    dh->dccph_type <= DCCP_PKT_DATAACK && dh->dccph_x == 0)  {
-		LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.type (%s) not Data||Ack||"
-					    "DataAck, while P.X == 0\n",
-			       dccp_packet_name(dh->dccph_type));
+		DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
+			  dccp_packet_name(dh->dccph_type));
 		return 1;
 	}
 
@@ -794,9 +791,8 @@ int dccp_invalid_packet(struct sk_buff *skb)
 	 */
 	cscov = dccp_csum_coverage(skb);
 	if (cscov > skb->len) {
-		LIMIT_NETDEBUG(KERN_WARNING
-			       "DCCP: P.CsCov %u exceeds packet length %d\n",
-			       dh->dccph_cscov, skb->len);
+		DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
+			  dh->dccph_cscov, skb->len);
 		return 1;
 	}
 
@@ -823,9 +819,7 @@ static int dccp_v4_rcv(struct sk_buff *skb)
 
 	/* Step 1: If header checksum is incorrect, drop packet and return */
 	if (dccp_v4_csum_finish(skb, skb->nh.iph->saddr, skb->nh.iph->daddr)) {
-		LIMIT_NETDEBUG(KERN_WARNING
-			       "%s: dropped packet with invalid checksum\n",
-			       __FUNCTION__);
+		DCCP_WARN("dropped packet with invalid checksum\n");
 		goto discard_it;
 	}
 

net/dccp/ipv6.c

@@ -828,9 +828,7 @@ static int dccp_v6_rcv(struct sk_buff **pskb)
 	/* Step 1: If header checksum is incorrect, drop packet and return. */
 	if (dccp_v6_csum_finish(skb, &skb->nh.ipv6h->saddr,
 				     &skb->nh.ipv6h->daddr)) {
-		LIMIT_NETDEBUG(KERN_WARNING
-			       "%s: dropped packet with invalid checksum\n",
-			       __FUNCTION__);
+		DCCP_WARN("dropped packet with invalid checksum\n");
 		goto discard_it;
 	}
 

net/dccp/minisocks.c

@@ -84,8 +84,7 @@ void dccp_time_wait(struct sock *sk, int state, int timeo)
 		 * socket up.  We've got bigger problems than
 		 * non-graceful socket closings.
 		 */
-		LIMIT_NETDEBUG(KERN_INFO "DCCP: time wait bucket "
-					 "table overflow\n");
+		DCCP_WARN("time wait bucket table overflow\n");
 	}
 
 	dccp_done(sk);
@@ -289,9 +288,7 @@ EXPORT_SYMBOL_GPL(dccp_child_process);
 
 void dccp_reqsk_send_ack(struct sk_buff *skb, struct request_sock *rsk)
 {
-	pr_info(KERN_WARNING "DCCP: ACK packets are never sent in "
-			     "LISTEN/RESPOND state\n");
-	dump_stack();
+	DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
 }
 
 EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);

net/dccp/options.c

@@ -238,9 +238,8 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
 		}
 			break;
 		default:
-			pr_info("DCCP(%p): option %d(len=%d) not "
-				"implemented, ignoring\n",
-				sk, opt, len);
+			DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
+				  "implemented, ignoring", sk, opt, len);
 			break;
 	        }
 
@@ -257,7 +256,7 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
 out_invalid_option:
 	DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
 	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
-	pr_info("DCCP(%p): invalid option %d, len=%d\n", sk, opt, len);
+	DCCP_WARN("DCCP(%p): invalid option %d, len=%d", sk, opt, len);
 	return -1;
 }
 
@@ -447,8 +446,7 @@ static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat,
 	u8 *to;
 
 	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) {
-		LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small"
-			       " to insert feature %d option!\n", feat);
+		DCCP_WARN("packet too small for feature %d option!\n", feat);
 		return -1;
 	}
 

net/dccp/output.c

@@ -257,11 +257,8 @@ void dccp_write_xmit(struct sock *sk, int block)
 				err = dccp_wait_for_ccid(sk, skb, &timeo);
 				timeo = DCCP_XMIT_TIMEO;
 			}
-			if (err) {
-				printk(KERN_CRIT "%s:err at dccp_wait_for_ccid"
-						 " %d\n", __FUNCTION__, err);
-				dump_stack();
-			}
+			if (err)
+				DCCP_BUG("err=%d after dccp_wait_for_ccid", err);
 		}
 
 		skb_dequeue(&sk->sk_write_queue);
@@ -283,12 +280,9 @@ void dccp_write_xmit(struct sock *sk, int block)
 
 			err = dccp_transmit_skb(sk, skb);
 			ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
-			if (err) {
-				printk(KERN_CRIT "%s:err from "
-					         "ccid_hc_tx_packet_sent %d\n",
-					         __FUNCTION__, err);
-				dump_stack();
-			}
+			if (err)
+				DCCP_BUG("err=%d after ccid_hc_tx_packet_sent",
+					 err);
 		} else
 			kfree(skb);
 	}

net/dccp/proto.c

@@ -1033,8 +1033,7 @@ static int __init dccp_init(void)
 	} while (!dccp_hashinfo.ehash && --ehash_order > 0);
 
 	if (!dccp_hashinfo.ehash) {
-		printk(KERN_CRIT "Failed to allocate DCCP "
-				 "established hash table\n");
+		DCCP_CRIT("Failed to allocate DCCP established hash table");
 		goto out_free_bind_bucket_cachep;
 	}
 
@@ -1056,7 +1055,7 @@ static int __init dccp_init(void)
 	} while (!dccp_hashinfo.bhash && --bhash_order >= 0);
 
 	if (!dccp_hashinfo.bhash) {
-		printk(KERN_CRIT "Failed to allocate DCCP bind hash table\n");
+		DCCP_CRIT("Failed to allocate DCCP bind hash table");
 		goto out_free_dccp_ehash;
 	}