Use glibc structure for __cmsg_nxthdr.

Bug: 13418328
Change-Id: I7e656b373e53e80d708325321e48dcedacf5086d
diff --git a/libc/Android.mk b/libc/Android.mk
index 44bf388..1008082 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -119,6 +119,7 @@
     bionic/chown.cpp \
     bionic/clock.cpp \
     bionic/clone.cpp \
+    bionic/cmsg_nxthdr.cpp \
     bionic/dirent.cpp \
     bionic/dup2.cpp \
     bionic/epoll_create.cpp \
diff --git a/libc/bionic/cmsg_nxthdr.cpp b/libc/bionic/cmsg_nxthdr.cpp
new file mode 100644
index 0000000..6f0a47c
--- /dev/null
+++ b/libc/bionic/cmsg_nxthdr.cpp
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/socket.h>
+
+cmsghdr* cmsg_nxthdr(msghdr* msg, cmsghdr* cmsg) {
+  cmsghdr* ptr;
+  ptr = reinterpret_cast<cmsghdr*>(reinterpret_cast<char*>(cmsg) + CMSG_ALIGN(cmsg->cmsg_len));
+  size_t len = reinterpret_cast<char*>(ptr+1) - reinterpret_cast<char*>(msg->msg_control);
+  if (len > msg->msg_controllen) {
+    return NULL;
+  }
+  return ptr;
+}
diff --git a/libc/include/sys/socket.h b/libc/include/sys/socket.h
index 86fd3cf..7edaac9 100644
--- a/libc/include/sys/socket.h
+++ b/libc/include/sys/socket.h
@@ -107,7 +107,7 @@
   int cmsg_type;
 };
 
-#define CMSG_NXTHDR(mhdr, cmsg) __cmsg_nxthdr((mhdr)->msg_control, (mhdr)->msg_controllen, (cmsg))
+#define CMSG_NXTHDR(mhdr, cmsg) cmsg_nxthdr((mhdr), (cmsg))
 #define CMSG_ALIGN(len) ( ((len)+sizeof(long)-1) & ~(sizeof(long)-1) )
 #define CMSG_DATA(cmsg) ((void*)((char*)(cmsg) + CMSG_ALIGN(sizeof(struct cmsghdr))))
 #define CMSG_SPACE(len) (CMSG_ALIGN(sizeof(struct cmsghdr)) + CMSG_ALIGN(len))
@@ -117,22 +117,7 @@
    ? (struct cmsghdr*) (msg)->msg_control : (struct cmsghdr*) NULL)
 #define CMSG_OK(mhdr, cmsg) ((cmsg)->cmsg_len >= sizeof(struct cmsghdr) &&   (cmsg)->cmsg_len <= (unsigned long)   ((mhdr)->msg_controllen -   ((char*)(cmsg) - (char*)(mhdr)->msg_control)))
 
-#ifdef __GNUC__
-#define __KINLINE static __inline__
-#elif defined(__cplusplus)
-#define __KINLINE static inline
-#else
-#define __KINLINE static
-#endif
-
-__KINLINE struct cmsghdr* __cmsg_nxthdr(void* __ctl, size_t __size, struct cmsghdr* __cmsg) {
-  struct cmsghdr* __ptr;
-  __ptr = (struct cmsghdr*)(((unsigned char*) __cmsg) + CMSG_ALIGN(__cmsg->cmsg_len));
-  if ((unsigned long)((char*)(__ptr+1) - (char*) __ctl) > __size) {
-    return NULL;
-  }
-  return __ptr;
-}
+struct cmsghdr* cmsg_nxthdr(struct msghdr*, struct cmsghdr*);
 
 #define SCM_RIGHTS 0x01
 #define SCM_CREDENTIALS 0x02