netdev - [iproute PATCH v2 7/7] ip/tcp_metrics: Simplify process

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Date:	Tue, 21 Jun 2016 18:18:41 +0200
From:	Phil Sutter <phil@....cc>
To:	Stephen Hemminger <shemming@...cade.com>
Cc:	Daniel Borkmann <daniel@...earbox.net>,
	David Ahern <dsa@...ulusnetworks.com>,
	Nicolas Dichtel <nicolas.dichtel@...nd.com>,
	Julien Floret <julien.floret@...nd.com>, netdev@...r.kernel.org
Subject: [iproute PATCH v2 7/7] ip/tcp_metrics: Simplify process_msg a bit

By combining the attribute extraction and check for existence, the
additional indentation level in the 'else' clause can be avoided.

In addition to that, common actions for 'daddr' are combined since the
function returns if neither of the branches are taken.

Signed-off-by: Phil Sutter <phil@....cc>
---
 ip/tcp_metrics.c | 45 ++++++++++++++++++---------------------------
 1 file changed, 18 insertions(+), 27 deletions(-)

diff --git a/ip/tcp_metrics.c b/ip/tcp_metrics.c
index f82604f458ada..899830c127bcb 100644
--- a/ip/tcp_metrics.c
+++ b/ip/tcp_metrics.c
@@ -112,47 +112,38 @@ static int process_msg(const struct sockaddr_nl *who, struct nlmsghdr *n,
 	parse_rtattr(attrs, TCP_METRICS_ATTR_MAX, (void *) ghdr + GENL_HDRLEN,
 		     len);
 
-	a = attrs[TCP_METRICS_ATTR_ADDR_IPV4];
-	if (a) {
+	if ((a = attrs[TCP_METRICS_ATTR_ADDR_IPV4])) {
 		if (f.daddr.family && f.daddr.family != AF_INET)
 			return 0;
-		memcpy(&daddr.data, RTA_DATA(a), 4);
 		daddr.bytelen = 4;
 		family = AF_INET;
 		atype = TCP_METRICS_ATTR_ADDR_IPV4;
-		dlen = RTA_PAYLOAD(a);
-	} else {
-		a = attrs[TCP_METRICS_ATTR_ADDR_IPV6];
-		if (a) {
-			if (f.daddr.family && f.daddr.family != AF_INET6)
-				return 0;
-			memcpy(&daddr.data, RTA_DATA(a), 16);
-			daddr.bytelen = 16;
-			family = AF_INET6;
-			atype = TCP_METRICS_ATTR_ADDR_IPV6;
-			dlen = RTA_PAYLOAD(a);
-		} else
+	} else if ((a = attrs[TCP_METRICS_ATTR_ADDR_IPV6])) {
+		if (f.daddr.family && f.daddr.family != AF_INET6)
 			return 0;
+		daddr.bytelen = 16;
+		family = AF_INET6;
+		atype = TCP_METRICS_ATTR_ADDR_IPV6;
+	} else {
+		return 0;
 	}
+	memcpy(&daddr.data, RTA_DATA(a), daddr.bytelen);
+	dlen = RTA_PAYLOAD(a);
 
-	a = attrs[TCP_METRICS_ATTR_SADDR_IPV4];
-	if (a) {
+	if ((a = attrs[TCP_METRICS_ATTR_SADDR_IPV4])) {
 		if (f.saddr.family && f.saddr.family != AF_INET)
 			return 0;
 		memcpy(&saddr.data, RTA_DATA(a), 4);
 		saddr.bytelen = 4;
 		stype = TCP_METRICS_ATTR_SADDR_IPV4;
 		slen = RTA_PAYLOAD(a);
-	} else {
-		a = attrs[TCP_METRICS_ATTR_SADDR_IPV6];
-		if (a) {
-			if (f.saddr.family && f.saddr.family != AF_INET6)
-				return 0;
-			memcpy(&saddr.data, RTA_DATA(a), 16);
-			saddr.bytelen = 16;
-			stype = TCP_METRICS_ATTR_SADDR_IPV6;
-			slen = RTA_PAYLOAD(a);
-		}
+	} else if ((a = attrs[TCP_METRICS_ATTR_SADDR_IPV6])) {
+		if (f.saddr.family && f.saddr.family != AF_INET6)
+			return 0;
+		memcpy(&saddr.data, RTA_DATA(a), 16);
+		saddr.bytelen = 16;
+		stype = TCP_METRICS_ATTR_SADDR_IPV6;
+		slen = RTA_PAYLOAD(a);
 	}
 
 	if (f.daddr.family && f.daddr.bitlen >= 0 &&
-- 
2.8.2