ip/tcp_metrics: Simplify process_msg a bit

On Tue, Jun 21, 2016 at 06:18 PM CEST, Phil Sutter <phil@nwl.cc> wrote:
> 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@nwl.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])) {

Copy the pointer inside the branch?

Same gain on indentation while keeping checkpatch happy.

I only compile-tested the patch below.

Thanks,
Jakub

diff --git a/ip/tcp_metrics.c b/ip/tcp_metrics.c
index f82604f458ada2823a36c2dd0ece5609baeac215..ac2613a0a880e81b99c8dfe2f2f21f971ba43fcb 100644 (file)
--- a/ip/tcp_metrics.c
+++ b/ip/tcp_metrics.c
@@ -112,47 +112,44 @@ 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 (attrs[TCP_METRICS_ATTR_ADDR_IPV4]) {
                if (f.daddr.family && f.daddr.family != AF_INET)
                        return 0;
+               a = attrs[TCP_METRICS_ATTR_ADDR_IPV4];
                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 (attrs[TCP_METRICS_ATTR_ADDR_IPV6]) {
+               if (f.daddr.family && f.daddr.family != AF_INET6)
                        return 0;
+               a = attrs[TCP_METRICS_ATTR_ADDR_IPV6];
+               memcpy(&daddr.data, RTA_DATA(a), 16);
+               daddr.bytelen = 16;
+               family = AF_INET6;
+               atype = TCP_METRICS_ATTR_ADDR_IPV6;
+               dlen = RTA_PAYLOAD(a);
+       } else {
+               return 0;
        }
 
-       a = attrs[TCP_METRICS_ATTR_SADDR_IPV4];
-       if (a) {
+       if (attrs[TCP_METRICS_ATTR_SADDR_IPV4]) {
                if (f.saddr.family && f.saddr.family != AF_INET)
                        return 0;
+               a = attrs[TCP_METRICS_ATTR_SADDR_IPV4];
                memcpy(&saddr.data, RTA_DATA(a), 4);
                saddr.bytelen = 4;
                stype = TCP_METRICS_ATTR_SADDR_IPV4;
                slen = RTA_PAYLOAD(a);
-       } else {
+       } else if (attrs[TCP_METRICS_ATTR_SADDR_IPV6]) {
+               if (f.saddr.family && f.saddr.family != AF_INET6)
+                       return 0;
                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);
-               }
+               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 &&