Merge pull request #14736 from opensourcerouting/transparent-sockunion

lib: create a transparent union `sockunion`
FRRouting · Nov 6, 2023 · b66dc09 · b66dc09
2 parents 23ebea3 + bf098b4
commit b66dc09
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Showing 4 changed files with 58 additions and 22 deletions.
diff --git a/lib/compiler.h b/lib/compiler.h
@@ -424,10 +424,10 @@ _Static_assert(sizeof(_uint64_t) == 8 && sizeof(_int64_t) == 8,
  * type.)
  */
 #ifndef __cplusplus
-#define prefixtype(uname, typename, fieldname) typename *fieldname;
+#define uniontype(uname, typename, fieldname) typename *fieldname;
 #define TRANSPARENT_UNION __attribute__((transparent_union))
 #else
-#define prefixtype(uname, typename, fieldname)                                 \
+#define uniontype(uname, typename, fieldname)                                  \
 	typename *fieldname;                                                   \
 	uname(typename *x)                                                     \
 	{                                                                      \

diff --git a/lib/prefix.h b/lib/prefix.h
@@ -286,23 +286,25 @@ struct prefix_sg {
 	struct in_addr grp;
 };
 
+/* clang-format off */
 union prefixptr {
-	prefixtype(prefixptr, struct prefix,      p)
-	prefixtype(prefixptr, struct prefix_ipv4, p4)
-	prefixtype(prefixptr, struct prefix_ipv6, p6)
-	prefixtype(prefixptr, struct prefix_evpn, evp)
-	prefixtype(prefixptr, struct prefix_fs,   fs)
-	prefixtype(prefixptr, struct prefix_rd,   rd)
+	uniontype(prefixptr, struct prefix,      p)
+	uniontype(prefixptr, struct prefix_ipv4, p4)
+	uniontype(prefixptr, struct prefix_ipv6, p6)
+	uniontype(prefixptr, struct prefix_evpn, evp)
+	uniontype(prefixptr, struct prefix_fs,   fs)
+	uniontype(prefixptr, struct prefix_rd,   rd)
 } TRANSPARENT_UNION;
 
 union prefixconstptr {
-	prefixtype(prefixconstptr, const struct prefix,      p)
-	prefixtype(prefixconstptr, const struct prefix_ipv4, p4)
-	prefixtype(prefixconstptr, const struct prefix_ipv6, p6)
-	prefixtype(prefixconstptr, const struct prefix_evpn, evp)
-	prefixtype(prefixconstptr, const struct prefix_fs,   fs)
-	prefixtype(prefixconstptr, const struct prefix_rd,   rd)
+	uniontype(prefixconstptr, const struct prefix,      p)
+	uniontype(prefixconstptr, const struct prefix_ipv4, p4)
+	uniontype(prefixconstptr, const struct prefix_ipv6, p6)
+	uniontype(prefixconstptr, const struct prefix_evpn, evp)
+	uniontype(prefixconstptr, const struct prefix_fs,   fs)
+	uniontype(prefixconstptr, const struct prefix_rd,   rd)
 } TRANSPARENT_UNION;
+/* clang-format on */
 
 #ifndef INET_ADDRSTRLEN
 #define INET_ADDRSTRLEN 16

diff --git a/lib/sockunion.h b/lib/sockunion.h
@@ -7,6 +7,8 @@
 #ifndef _ZEBRA_SOCKUNION_H
 #define _ZEBRA_SOCKUNION_H
 
+#include "compiler.h"
+
 #include "privs.h"
 #include "if.h"
 #include <sys/un.h>
@@ -27,8 +29,40 @@ union sockunion {
 	struct sockaddr_mpls smpls;
 	struct sockaddr_rtlabel rtlabel;
 #endif
+
+	/* sockaddr_storage is guaranteed to be larger than the others */
+	struct sockaddr_storage sa_storage;
 };
 
+/* clang-format off */
+/* for functions that want to accept any sockaddr pointer without casts */
+union sockaddrptr {
+	uniontype(sockaddrptr, union sockunion, su)
+	uniontype(sockaddrptr, struct sockaddr, sa)
+	uniontype(sockaddrptr, struct sockaddr_in, sin)
+	uniontype(sockaddrptr, struct sockaddr_in6, sin6)
+	uniontype(sockaddrptr, struct sockaddr_un, sun)
+#ifdef __OpenBSD__
+	uniontype(sockaddrptr, struct sockaddr_mpls, smpls)
+	uniontype(sockaddrptr, struct sockaddr_rtlabel, rtlabel)
+#endif
+	uniontype(sockaddrptr, struct sockaddr_storage, sa_storage)
+} TRANSPARENT_UNION;
+
+union sockaddrconstptr {
+	uniontype(sockaddrconstptr, const union sockunion, su)
+	uniontype(sockaddrconstptr, const struct sockaddr, sa)
+	uniontype(sockaddrconstptr, const struct sockaddr_in, sin)
+	uniontype(sockaddrconstptr, const struct sockaddr_in6, sin6)
+	uniontype(sockaddrconstptr, const struct sockaddr_un, sun)
+#ifdef __OpenBSD__
+	uniontype(sockaddrconstptr, const struct sockaddr_mpls, smpls)
+	uniontype(sockaddrconstptr, const struct sockaddr_rtlabel, rtlabel)
+#endif
+	uniontype(sockaddrconstptr, const struct sockaddr_storage, sa_storage)
+} TRANSPARENT_UNION;
+/* clang-format on */
+
 enum connect_result { connect_error, connect_success, connect_in_progress };
 
 /* Default address family. */

diff --git a/pimd/pim_addr.h b/pimd/pim_addr.h
@@ -33,13 +33,13 @@ typedef struct in_addr pim_addr;
 #define PIM_ADDR_FUNCNAME(name) ipv4_##name
 
 union pimprefixptr {
-	prefixtype(pimprefixptr, struct prefix,      p)
-	prefixtype(pimprefixptr, struct prefix_ipv4, p4)
+	uniontype(pimprefixptr, struct prefix,      p)
+	uniontype(pimprefixptr, struct prefix_ipv4, p4)
 } TRANSPARENT_UNION;
 
 union pimprefixconstptr {
-	prefixtype(pimprefixconstptr, const struct prefix,      p)
-	prefixtype(pimprefixconstptr, const struct prefix_ipv4, p4)
+	uniontype(pimprefixconstptr, const struct prefix,      p)
+	uniontype(pimprefixconstptr, const struct prefix_ipv4, p4)
 } TRANSPARENT_UNION;
 
 #else
@@ -63,13 +63,13 @@ typedef struct in6_addr pim_addr;
 #define PIM_ADDR_FUNCNAME(name) ipv6_##name
 
 union pimprefixptr {
-	prefixtype(pimprefixptr, struct prefix,      p)
-	prefixtype(pimprefixptr, struct prefix_ipv6, p6)
+	uniontype(pimprefixptr, struct prefix,      p)
+	uniontype(pimprefixptr, struct prefix_ipv6, p6)
 } TRANSPARENT_UNION;
 
 union pimprefixconstptr {
-	prefixtype(pimprefixconstptr, const struct prefix,      p)
-	prefixtype(pimprefixconstptr, const struct prefix_ipv6, p6)
+	uniontype(pimprefixconstptr, const struct prefix,      p)
+	uniontype(pimprefixconstptr, const struct prefix_ipv6, p6)
 } TRANSPARENT_UNION;
 #endif