ip: IP cmsg cleanup

Move the IP_CMSG_* constants from ip_sockglue.c to inet_sock.h so that
they can be referenced in other source files.

Restructure ip_cmsg_recv to not go through flags using shift, check
for flags by 'and'. This eliminates both the shift and a conditional
per flag check.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 47 insertions, 28 deletions

diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 360b110b3e36..605ca421d5ab 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -16,7 +16,7 @@
 #ifndef _INET_SOCK_H
 #define _INET_SOCK_H
 
-
+#include <linux/bitops.h>
 #include <linux/kmemcheck.h>
 #include <linux/string.h>
 #include <linux/types.h>
@@ -195,6 +195,15 @@ struct inet_sock {
 #define IPCORK_OPT      1       /* ip-options has been held in ipcork.opt */
 #define IPCORK_ALLFRAG  2       /* always fragment (for ipv6 for now) */
 
+/* cmsg flags for inet */
+#define IP_CMSG_PKTINFO         BIT(0)
+#define IP_CMSG_TTL             BIT(1)
+#define IP_CMSG_TOS             BIT(2)
+#define IP_CMSG_RECVOPTS        BIT(3)
+#define IP_CMSG_RETOPTS         BIT(4)
+#define IP_CMSG_PASSSEC         BIT(5)
+#define IP_CMSG_ORIGDSTADDR     BIT(6)
+
 static inline struct inet_sock *inet_sk(const struct sock *sk)
 {
         return (struct inet_sock *)sk;
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 8a89c738b7a3..80f78565b41b 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -45,14 +45,6 @@
 #include <linux/errqueue.h>
 #include <asm/uaccess.h>
 
-#define IP_CMSG_PKTINFO         1
-#define IP_CMSG_TTL             2
-#define IP_CMSG_TOS             4
-#define IP_CMSG_RECVOPTS        8
-#define IP_CMSG_RETOPTS         16
-#define IP_CMSG_PASSSEC         32
-#define IP_CMSG_ORIGDSTADDR     64
-
 /*
  *      SOL_IP control messages.
  */
@@ -150,37 +142,55 @@ void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
         unsigned int flags = inet->cmsg_flags;
 
         /* Ordered by supposed usage frequency */
-        if (flags & 1)
+        if (flags & IP_CMSG_PKTINFO) {
                 ip_cmsg_recv_pktinfo(msg, skb);
-        if ((flags >>= 1) == 0)
-                return;
 
-        if (flags & 1)
+                flags &= ~IP_CMSG_PKTINFO;
+                if (!flags)
+                        return;
+        }
+
+        if (flags & IP_CMSG_TTL) {
                 ip_cmsg_recv_ttl(msg, skb);
-        if ((flags >>= 1) == 0)
-                return;
 
-        if (flags & 1)
+                flags &= ~IP_CMSG_TTL;
+                if (!flags)
+                        return;
+        }
+
+        if (flags & IP_CMSG_TOS) {
                 ip_cmsg_recv_tos(msg, skb);
-        if ((flags >>= 1) == 0)
-                return;
 
-        if (flags & 1)
+                flags &= ~IP_CMSG_TOS;
+                if (!flags)
+                        return;
+        }
+
+        if (flags & IP_CMSG_RECVOPTS) {
                 ip_cmsg_recv_opts(msg, skb);
-        if ((flags >>= 1) == 0)
-                return;
 
-        if (flags & 1)
+                flags &= ~IP_CMSG_RECVOPTS;
+                if (!flags)
+                        return;
+        }
+
+        if (flags & IP_CMSG_RETOPTS) {
                 ip_cmsg_recv_retopts(msg, skb);
-        if ((flags >>= 1) == 0)
-                return;
 
-        if (flags & 1)
+                flags &= ~IP_CMSG_RETOPTS;
+                if (!flags)
+                        return;
+        }
+
+        if (flags & IP_CMSG_PASSSEC) {
                 ip_cmsg_recv_security(msg, skb);
 
-        if ((flags >>= 1) == 0)
-                return;
-        if (flags & 1)
+                flags &= ~IP_CMSG_PASSSEC;
+                if (!flags)
+                        return;
+        }
+
+        if (flags & IP_CMSG_ORIGDSTADDR)
                 ip_cmsg_recv_dstaddr(msg, skb);
 
 }