Page MenuHomeFreeBSD
Files F143876895

D21669.diff
No OneTemporary
Actions

D21669.diff
View Options

Index: sys/netinet/ip_options.c
===================================================================
--- sys/netinet/ip_options.c
+++ sys/netinet/ip_options.c
@@ -101,7 +101,7 @@
int
ip_dooptions(struct mbuf *m, int pass)
{
- struct ip *ip = mtod(m, struct ip *);
+ struct ip *ip = mtod(m);
u_char *cp;
struct in_ifaddr *ia;
int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
@@ -453,7 +453,7 @@
* First, save first hop for return route.
*/
p = &(opts->ip_srcrt.route[opts->ip_nhops - 1]);
- *(mtod(m, struct in_addr *)) = *p--;
+ *((struct in_addr *)mtod(m)) = *p--;
/*
* Copy option fields and padding (nop) to mbuf.
@@ -486,7 +486,7 @@
void
ip_stripoptions(struct mbuf *m)
{
- struct ip *ip = mtod(m, struct ip *);
+ struct ip *ip = mtod(m);
int olen;
olen = (ip->ip_hl << 2) - sizeof(struct ip);
@@ -510,9 +510,9 @@
struct mbuf *
ip_insertoptions(struct mbuf *m, struct mbuf *opt, int *phlen)
{
- struct ipoption *p = mtod(opt, struct ipoption *);
+ struct ipoption *p = mtod(opt);
struct mbuf *n;
- struct ip *ip = mtod(m, struct ip *);
+ struct ip *ip = mtod(m);
unsigned optlen;
optlen = opt->m_len - sizeof(p->ipopt_dst);
@@ -537,14 +537,14 @@
m = n;
m->m_len = optlen + sizeof(struct ip);
m->m_data += max_linkhdr;
- bcopy(ip, mtod(m, void *), sizeof(struct ip));
+ bcopy(ip, mtod(m), sizeof(struct ip));
} else {
m->m_data -= optlen;
m->m_len += optlen;
m->m_pkthdr.len += optlen;
- bcopy(ip, mtod(m, void *), sizeof(struct ip));
+ bcopy(ip, mtod(m), sizeof(struct ip));
}
- ip = mtod(m, struct ip *);
+ ip = (struct ip *)mtod(m);
bcopy(p->ipopt_list, ip + 1, optlen);
*phlen = sizeof(struct ip) + optlen;
ip->ip_v = IPVERSION;
@@ -636,9 +636,9 @@
goto bad;
cnt = m->m_len;
m->m_len += sizeof(struct in_addr);
- cp = mtod(m, u_char *) + sizeof(struct in_addr);
- bcopy(mtod(m, void *), cp, (unsigned)cnt);
- bzero(mtod(m, void *), sizeof(struct in_addr));
+ cp = (u_char *)mtod(m) + sizeof(struct in_addr);
+ bcopy(mtod(m), cp, (unsigned)cnt);
+ bzero(mtod(m), sizeof(struct in_addr));
for (; cnt > 0; cnt -= optlen, cp += optlen) {
opt = cp[IPOPT_OPTVAL];
@@ -722,7 +722,7 @@
int
ip_checkrouteralert(struct mbuf *m)
{
- struct ip *ip = mtod(m, struct ip *);
+ struct ip *ip = mtod(m);
u_char *cp;
int opt, optlen, cnt, found_ra;
Index: sys/sys/mbuf.h
===================================================================
--- sys/sys/mbuf.h
+++ sys/sys/mbuf.h
@@ -103,13 +103,45 @@
#ifdef _KERNEL
/*-
- * Macro for type conversion: convert mbuf pointer to data pointer of correct
- * type:
+ * Convert mbuf pointers into various possible pointers to mbuf data.
*
- * mtod(m, t) -- Convert mbuf pointer to data pointer of correct type.
- * mtodo(m, o) -- Same as above but with offset 'o' into data.
+ * mtod(m) -- Convert mbuf pointer to void pointer of correct const.
+ * mtod(m, t) -- Convert mbuf pointer to pointer of type t (legacy)
+ * mtodo(m, o) -- Convert mbuf pointer to void pointer at offset 'o'.
*/
-#define mtod(m, t) ((t)((m)->m_data))
+#if __STDC_VERSION__ >= 201112L
+#define __mtod_1(m) \
+ _Generic((m), \
+ const struct mbuf *: (const void *)(m)->m_data, \
+ struct mbuf *: (void *)(m)->m_data \
+ )
+#else /* < C11 */
+#define __mtod_1(m) __DECONST(void *, (m)->m_data)
+#endif
+
+#define __mtod_2(m, t) ((t)((m)->m_data))
+
+/*
+ * Ugliness starting here encapsulates an mtod() macro that takes either one or
+ * two parameters.
+ *
+ * This first bit counts the number of variadic arguments in '...'. That is,
+ * __mtod_narg() returns either 1 or 2.
+ */
+#define __mtod_arg_n(_1, _2, N, ...) N
+#define __mtod_narg_(...) __mtod_arg_n(__VA_ARGS__)
+#define __mtod_narg(...) __mtod_narg_(__VA_ARGS__, 2, 1)
+
+/*
+ * Given the number of arguments counted by __mtod_narg(), __mtod()
+ * concatenates the number to a prefix to select the correct version of the
+ * macro.
+ */
+#define __mtod(N, ...) __CONCAT(__mtod_, N)(__VA_ARGS__)
+
+#define mtod(...) __mtod(__mtod_narg(__VA_ARGS__), __VA_ARGS__)
+/* End of mtod(m [, t]) ugliness. */
+
#define mtodo(m, o) ((void *)(((m)->m_data) + (o)))
/*
Index: tools/coccinelle/convert_mtod_2_to_1_arg.cocci
===================================================================
--- /dev/null
+++ tools/coccinelle/convert_mtod_2_to_1_arg.cocci
@@ -0,0 +1,36 @@
+// Convert mtod() macro to a typeless version, leaving explicit casts
+// for now in case people rely on them for legibility in large
+// functions.
+
+// Drop explicit casts to void* and const void*, as those cannot possibly
+// inform about the resulting data type.
+
+// Also drop casts when mtod() is used during declaration (bad style, but it
+// exists in the codebase).
+
+@r1@
+expression m;
+type t;
+identifier i;
+@@
+
+-t i = mtod(m, t);
++t i = mtod(m);
+
+
+@r2@
+expression m;
+type t;
+identifier i;
+@@
+
+(
+-mtod(m, void *)
++mtod(m)
+|
+-mtod(m, const void *)
++mtod(m)
+|
+-mtod(m, t)
++(t)mtod(m)
+)

File Metadata

Mime Type
text/plain
Expires
Mon, Feb 2, 9:38 AM (38 m, 37 s)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
28411957
Default Alt Text
D21669.diff (4 KB)

Event Timeline