[libc-commits] [libc] 12d4889 - [libc] Add `IN6_IS_ADDR_MC*` (#172643)

[via libc-commits]

Author: Connector Switch
Date: 2025-12-18T23:11:35+08:00
New Revision: 12d4889a0aa5ff816db818ca43f2bbb71610a0b2

URL: https://github.com/llvm/llvm-project/commit/12d4889a0aa5ff816db818ca43f2bbb71610a0b2
DIFF: https://github.com/llvm/llvm-project/commit/12d4889a0aa5ff816db818ca43f2bbb71610a0b2.diff

LOG: [libc] Add `IN6_IS_ADDR_MC*` (#172643)

This patch adds the `IN6_IS_ADDR_MC*` macro, which checks whether an
address is multicast node-local address, multicast link-local address,
multicast site-local address, multicast organization-local address and
multicast global address.

Added: 
    

Modified: 
    libc/include/llvm-libc-macros/netinet-in-macros.h
    libc/test/include/netinet_in_test.cpp

Removed: 
    


################################################################################
diff  --git a/libc/include/llvm-libc-macros/netinet-in-macros.h b/libc/include/llvm-libc-macros/netinet-in-macros.h
index 863ff8759e446..88ffe92756b16 100644
--- a/libc/include/llvm-libc-macros/netinet-in-macros.h
+++ b/libc/include/llvm-libc-macros/netinet-in-macros.h
@@ -64,4 +64,24 @@
   ((__LLVM_LIBC_CAST(reinterpret_cast, uint8_t *, a)[0]) == 0xfe &&            \
    (__LLVM_LIBC_CAST(reinterpret_cast, uint8_t *, a)[1] & 0xc0) == 0xc0)
 
+#define IN6_IS_ADDR_MC_NODELOCAL(a)                                            \
+  (IN6_IS_ADDR_MULTICAST(a) &&                                                 \
+   (__LLVM_LIBC_CAST(reinterpret_cast, uint8_t *, a)[1] & 0xf) == 0x1)
+
+#define IN6_IS_ADDR_MC_LINKLOCAL(a)                                            \
+  (IN6_IS_ADDR_MULTICAST(a) &&                                                 \
+   (__LLVM_LIBC_CAST(reinterpret_cast, uint8_t *, a)[1] & 0xf) == 0x2)
+
+#define IN6_IS_ADDR_MC_SITELOCAL(a)                                            \
+  (IN6_IS_ADDR_MULTICAST(a) &&                                                 \
+   (__LLVM_LIBC_CAST(reinterpret_cast, uint8_t *, a)[1] & 0xf) == 0x5)
+
+#define IN6_IS_ADDR_MC_ORGLOCAL(a)                                             \
+  (IN6_IS_ADDR_MULTICAST(a) &&                                                 \
+   (__LLVM_LIBC_CAST(reinterpret_cast, uint8_t *, a)[1] & 0xf) == 0x8)
+
+#define IN6_IS_ADDR_MC_GLOBAL(a)                                               \
+  (IN6_IS_ADDR_MULTICAST(a) &&                                                 \
+   (__LLVM_LIBC_CAST(reinterpret_cast, uint8_t *, a)[1] & 0xf) == 0xe)
+
 #endif // LLVM_LIBC_MACROS_NETINET_IN_MACROS_H

diff  --git a/libc/test/include/netinet_in_test.cpp b/libc/test/include/netinet_in_test.cpp
index e8cb8e48ff4b4..72500c4d51438 100644
--- a/libc/test/include/netinet_in_test.cpp
+++ b/libc/test/include/netinet_in_test.cpp
@@ -42,4 +42,18 @@ TEST(LlvmLibcNetinetInTest, IN6Macro) {
   buff[0] = 0xff;
   buff[1] = 0x80;
   EXPECT_FALSE(IN6_IS_ADDR_SITELOCAL(buff));
+
+  buff[0] = 0xff;
+  buff[1] = 0x1;
+  EXPECT_TRUE(IN6_IS_ADDR_MC_NODELOCAL(buff));
+  buff[1] = 0x2;
+  EXPECT_TRUE(IN6_IS_ADDR_MC_LINKLOCAL(buff));
+  buff[1] = 0x5;
+  EXPECT_TRUE(IN6_IS_ADDR_MC_SITELOCAL(buff));
+  buff[1] = 0x8;
+  EXPECT_TRUE(IN6_IS_ADDR_MC_ORGLOCAL(buff));
+  buff[1] = 0xe;
+  EXPECT_TRUE(IN6_IS_ADDR_MC_GLOBAL(buff));
+  buff[1] = 0;
+  buff[0] = 0;
 }